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Sample records for contact time ph

  1. Adhesion of alkane as a functional group on muscovite and quartz: dependence on pH and contact time.

    Science.gov (United States)

    Juhl, K M S; Pedersen, C S; Bovet, N; Dalby, K N; Hassenkam, T; Andersson, M P; Okhrimenko, D; Stipp, S L S

    2014-12-09

    The interactions between mineral surfaces and organic molecules in water control many processes in nature and in the production of modern materials. To improve the understanding of fluid-surface interactions, we investigated the interface behavior of quartz and muscovite, a model for clay minerals, in aqueous solutions where the pH and composition were controlled. We used atomic force microscopy (AFM) in chemical force mapping (CFM) mode to measure adhesion using tips functionalized with alkyl, -CH3. By combining adhesion forces measured as a function of pH, with data from streaming potential experiments and DLVO calculations, we were able to determine the surface charge density. We observed increased adhesion between the mineral surface and the hydrophobic tips as the contact time increased from 7 ms to ∼2 s. The diffusion of dissolved ions takes time, and density functional theory (DFT) calculations did not indicate a strong hydration of the mineral surfaces. Therefore, we interpret that the loss of ions from the confined space between the tip and sample is a likely explanation of the correlation between the dwell time and adhesion. The maximum adhesion increase with dwell time for muscovite, i.e., 400 ± 77 pN, was considerably larger than for quartz, 84 ± 15 pN, which fits with the different surface structure and composition of the two minerals. We propose two mechanisms to explain these results: (1) cations that are structured in the solution and on the surface remain associated at the tip-sample interface initially but diffuse away during extended contact time and (2) adventitious carbon, the organic material that comes spontaneously from air and solution, can diffuse to the tip-sample interface during contact. This material decreases the surface energy by aggregating near the alkyl tip and increases adhesion between the tip and sample.

  2. Simultaneous removal of As, Cd, Cr, Cu, Ni and Zn from stormwater using high-efficiency industrial sorbents: Effect of pH, contact time and humic acid

    DEFF Research Database (Denmark)

    Genc-Fuhrman, Hülya; Mikkelsen, Peter Steen; Ledin, Anna

    2016-01-01

    The effect of contact time, solution pH, and the presence of humic acid (HA) on the combined removal of As, Cd, Cr, Cu, Ni and Zn is investigated in batch tests using alumina, granulated activated carbon (GAC), and bauxsol coated sand (BCS) as sorbents. It is found that the equilibrium time for Cd...

  3. Reaction rate of NaOCl in contact with bovine dentine: effect of activation, exposure time, concentration and pH.

    NARCIS (Netherlands)

    de Macedo, R.G.; Wesselink, P.R.; Zaccheo, F.; Fanali, D.; van der Sluis, L.W.M.

    2010-01-01

    Aim  To determine the influence of activation method (ultrasound or laser), concentration, pH and exposure time on the reaction rate (RR) of NaOCl when in contact with dentinal walls. Methodology  The walls from standardized root canals in bovine incisors were exposed to a standardized volume of sod

  4. ATR-FTIR spectroscopy study of the influence of pH and contact time on the adhesion of Shewanella putrefaciens bacterial cells to the surface of hematite.

    Science.gov (United States)

    Elzinga, Evert J; Huang, Jen-How; Chorover, Jon; Kretzschmar, Ruben

    2012-12-04

    Attachment of live cells of Shewanella putrefaciens strain CN-32 to the surface of hematite (α-Fe(2)O(3)) was studied with in situ ATR-FTIR spectroscopy at variable pH (4.5-7.7) and contact times up to 24 h. The IR spectra indicate that phosphate based functional groups on the cell wall play an important role in mediating adhesion through formation of inner-sphere coordinative bonds to hematite surface sites. The inner-sphere attachment mode of microbial P groups varies with pH, involving either a change in protonation or in coordination to hematite surface sites as pH is modified. At all pH values, spectra collected during the early stages of adhesion show intense IR bands associated with reactive P-groups, suggestive of preferential coordination of P-moieties at the hematite surface. Spectra collected after longer sorption times show distinct frequencies from cell wall protein and carboxyl groups, indicating that bacterial adhesion occurring over longer time scales is to a lesser degree associated with preferential attachment of P-based bacterial functional groups to the hematite surface. The results of this study demonstrate that pH and reaction time influence cell-mineral interactions, implying that these parameters play an important role in determining cell mobility and biofilm formation in aqueous geochemical environments.

  5. Sorption properties of Th(IV) on the raw diatomite--effects of contact time, pH, ionic strength and temperature.

    Science.gov (United States)

    Sheng, Guodong; Hu, Jun; Wang, Xiangke

    2008-10-01

    Diatomite has a number of unique physicochemical properties and has diversified industrial uses. Natural diatomite has been tested as a potential sorbent for the removal of Th(IV) from aqueous solutions. The results indicate that sorption of Th(IV) is strongly dependent on ionic strength at pH3. Outer-sphere complexation or ion exchange may be the main sorption mechanism of Th(IV) to diatomite at low pH values, whereas the sorption of Th(IV) at pH>3 is mainly dominated by inner-sphere complexation or precipitation. The competition for Th(IV) between aqueous or surface adsorbed anions (e.g., herein ClO(4)(-), NO(3)(-) and Cl(-)) and surface functional groups of diatomite is important for Th(IV) sorption. The thermodynamic data (DeltaH(0), DeltaS(0), DeltaG(0)) are calculated from the temperature-dependent sorption isotherms. The results suggest that sorption process of Th(IV) on diatomite is spontaneous and endothermic.

  6. Water soluble drug releasing soft contact lens in response to pH of tears

    Science.gov (United States)

    Kim, G.; Noh, H.

    2016-06-01

    Human tear characteristics including pH and compositions can vary significantly depending on physical and environmental factors. Contact lenses directly contact with human tears can be swelled or de-swelled depending on the pH of the solution due to the nature of the hydrogel. For examples, anionic hydrogels, when the solution's pH is low, is shrunken due to the electric attraction force within the hydrogel network; the opposite phenomenon appears when the solution is basic. The purpose of this study was to evaluate the extent of water soluble drug, hydroxyl propyl methyl cellulose, released from contact lens according to the pH of the artificial tears. Artificial tears are prepared by mixing lysozyme, albumin, sodium chloride, potassium chloride, and calcium chloride following physiological concentrations. Hydrogel contact lens was thermally polymerized using HEMA, EGDMA, and AIBN. The prepared hydrogel lens was immersed in drug for 3 hours and the eluted drug mass was measured as a function of the time. As a result, the drug was released from the lens for 12 hours in all the pH of artificial tears. At the lower pH of artificial tears (pH 5.8), the total amount of dye emitted from the lens was increased than the total amount of dye emitted at the basic tear (pH 8.4). Also, initial burst at acidic tears was increased within 1 hour. Release pattern of water-soluble drug from hydrogel lens turned out to be different depending on the pH of the artificial tears. When designing drug releasing contact lens, physiological pH of tears should be considered.

  7. Close Contact Fluctuations: Time of Contact

    CERN Document Server

    Bush, Daniel R

    2014-01-01

    The letter resolves the long standing debate as to the proper time scale ($$) of the onset of the immunological synapse (IS) bond, the non-covalent chemical bond defining the immune pathways involving T-cells and antigen presenting cells (APC). Results from our model calculations show $$ to be of the order of seconds instead of minutes. Close to the linearly stable regime, we show that in between the two critical spatial thresholds defined by the integrin:ligand pair ($\\Delta_2\\sim$ 40-45 nm) and the T cell receptor (TCR):pMHC bond ($\\Delta_1\\sim$ 14-15 nm), $$ grows monotonically with increasing co-receptor bond length separation $\\delta$ (= $\\Delta_2-\\Delta_1\\sim$ 26-30 nm) while $$ decays with $\\Delta_1$ for fixed $\\Delta_2$. The non-universal $\\delta$-dependent power-law structure of the probability density function (PDF) further explains why only the TCR:pMHC bond is a likely candidate to form a stable synapse.

  8. A noise-resistant ADSA-PH algorithm for superhydrophobic surface's static contact angle evaluation

    Science.gov (United States)

    Xu, Z. N.

    2017-03-01

    The blur around the contact points significantly decreases the evaluated static contact angle for superhydrophobic surface which is clearly presented in the paper. To improve the accuracy in the evaluated static contact angle for superhydrophobic surface, an accurate static contact angle algorithm, namely ADSA-PH (axisymmetric drop shape analysis-profile and height), is proposed. It discards the extracted drop edge points close to the contact points and makes use of the residual points and the drop height to determine the static contact angle. The contact angle errors caused by the blur close to the contact points are significantly reduced. The classical ADSA-P algorithm, the modified selected-plane method and the proposed algorithm are used to evaluate static contact angle. The results validate the proposed algorithm. The accuracy in the evaluated contact angle increases with increasing image resolution. To reduce the error caused by a limitation of image resolution, the minimum allowable image resolutions are presented.

  9. Space time manifolds and contact structures

    Directory of Open Access Journals (Sweden)

    K. L. Duggal

    1990-01-01

    Full Text Available A new class of contact manifolds (carring a global non-vanishing timelike vector field is introduced to establish a relation between spacetime manifolds and contact structures. We show that odd dimensional strongly causal (in particular, globally hyperbolic spacetimes can carry a regular contact structure. As examples, we present a causal spacetime with a non regular contact structure and a physical model [Gödel Universe] of Homogeneous contact manifold. Finally, we construct a model of 4-dimensional spacetime of general relativity as a contact CR-submanifold.

  10. Time dependence of the pH of rain

    Science.gov (United States)

    John A. Kadlecek; Volkar A. Mohnen

    1976-01-01

    Standard procedures for determining the pH of rain samples usually involve substantial delays from the time of rainfall to the time of analysis. This assumes that no change in pH occurs during the storage period. We have found that this is not always true. We have determined that individual rain water samples possess a time dependent pH which can be correlated with the...

  11. Effects of pH value and coagulant dosage on contact filtration of humic substances

    Institute of Scientific and Technical Information of China (English)

    蒋绍阶; 刘宗源; 梁建军

    2009-01-01

    Humic substances (especially fulvic acid (FA)) are the major components of natural organic matter (NOM) that widely exist in drinking water source. Due to their potential effects on public health,the removal of FA was one of the main concerns during the water treatment. Therefore,the contact filtration of FA by using aluminum sulfate as coagulant on the basis of jar tests was carried out. The effects of pH and coagulant dosage on the FA removal and the development of head loss were investigated. The results show that the range of pH value during the FA contact filtration can be effectively influenced by the dosage of aluminum sulfate,and the high aluminum sulfate dosage is an important factor that can result in early filter breakthrough. The FA filtration by deep-bed filtration or by membrane filtration is sometimes disparate under the same coagulation conditions. The choice of aluminum sulfate dosage by the method of membrane filtration,i.e. the "true color measurement",may result in inappropriate filter run,whereas it can be determined with simple jar tests by observing the formation of micro flocs. Considering the effects of pH on aluminum sulfate dosage and FA removal,the optimal pH range of 5.5?6.0 is suggested.

  12. Adhesion of Pathogenic Bacteria to Food Contact Surfaces: Influence of pH of Culture

    Directory of Open Access Journals (Sweden)

    Akier Assanta Mafu

    2011-01-01

    Full Text Available The adhesion of Aeromonas hydrophila, Escherichia coli O157:H7, Salmonella Enteritidis, and Staphylococcus aureus to hydrophobic and hydrophilic surfaces in cultures with different pHs (6, 7, and 8 was studied. The results indicated that the type of material had no effect on the attachment capacity of microorganisms, while environmental pH influenced the adhesion of A. hydrophila, E. coli, and S. aureus to both solid substrates. The attachment of S. Enteritidis (P>.05 was not affected by the type of substrate or the culture pH, whereas E. coli displayed the weakest affinity for both polystyrene and glass surfaces. No correlation was established between the physicochemical properties of the materials, or the bacterial and the rate of bacterial adhesion, except for S. aureus. Photomicrographs have shown that surfaces were contaminated by small clusters of S. Enteritidis while S. aureus invaded the food contact surfaces in the form of small chains or cell aggregates.

  13. Wettability and Contact Time on a Biomimetic Superhydrophobic Surface

    Directory of Open Access Journals (Sweden)

    Yunhong Liang

    2017-03-01

    Full Text Available Inspired by the array microstructure of natural superhydrophobic surfaces (lotus leaf and cicada wing, an array microstructure was successfully constructed by high speed wire electrical discharge machining (HS-WEDM on the surfaces of a 7075 aluminum alloy without any chemical treatment. The artificial surfaces had a high apparent contact angle of 153° ± 1° with a contact angle hysteresis less than 5° and showed a good superhydrophobic property. Wettability, contact time, and the corresponding superhydrophobic mechanism of artificial superhydrophobic surface were investigated. The results indicated that the micro-scale array microstructure was an important factor for the superhydrophobic surface, while different array microstructures exhibited different effects on the wettability and contact time of the artificial superhydrophobic surface. The length (L, interval (S, and height (H of the array microstructure are the main influential factors on the wettability and contact time. The order of importance of these factors is H > S > L for increasing the apparent contact angle and reducing the contact time. The method, using HS-WEDM to fabricate superhydrophobic surface, is simple, low-cost, and environmentally friendly and can easily control the wettability and contact time on the artificial surfaces by changing the array microstructure.

  14. Time course of pH change in plant epidermis using microscopic pH imaging system

    Science.gov (United States)

    Dan, Risako; Shimizu, Megumi; Kazama, Haruko; Sakaue, Hirotaka

    2010-11-01

    We established a microscopic pH imaging system to track the time course of pH change in plant epidermis in vivo. In the previous research, we have found out that anthocyanin containing cells have higher pH. However, it was not clear whether the anthocyanin increased the pH or anthocyanin was synthesized result from the higher pH. Therefore, we further investigated the relationship between anthocyanin and pH change. To track the time course of pH change in plant epidermis, we established a system using luminescent imaging technique. We used HPTS (8-Hydroxypyrene-1,3,6-Trisulfonate) as pH indicator and applied excitation ratio imaging method. Luminescent image was converted to a pH distribution by obtained in vitro calibration using known pH solution. Cellular level observation was enabled by merging microscopic color picture of the same region to the pH change image. The established system was applied to epidermal cells of red-tip leaf lettuce, Lactuca Sativa L. and the time course was tracked in the growth process. We would discuss about the relationship between anthocyanin and pH change in plant epidermis.

  15. Bilateral contact ground reaction forces and contact times during plyometric drop jumping.

    Science.gov (United States)

    Ball, Nick B; Stock, Christopher G; Scurr, Joanna C

    2010-10-01

    Drop jumping (DJ) is used in training programs aimed to improve lower extremity explosive power. When performing double-leg drop jumps, it is important to provide an equal stimulus to both legs to ensure balanced development of the lower legs. The aim of this study was to bilaterally analyze the ground reactions forces and temporal components of drop jumping from 3 heights. Ten recreationally active male subjects completed 3 bounce-drop jumps from 3 starting heights (0.2, 0.4, and 0.6 m). Two linked force platforms were used to record left- and right-leg peak vertical force, time to peak force, average force, ground contact time, impulse and time differential. Between-height and between-leg comparisons for each variable were made using a multivariate analysis of variance with post hoc Wilcoxon tests (p vertical forces and temporal components occur; however, shorter contact times were found at the lower heights.

  16. Mechatronic modeling of real-time wheel-rail contact

    CERN Document Server

    Bosso, Nicola; Gugliotta, Antonio; Somà, Aurelio

    2013-01-01

    Real-time simulations of the behaviour of a rail vehicle require realistic solutions of the wheel-rail contact problem which can work in a real-time mode. Examples of such solutions for the online mode have been well known and are implemented within standard and commercial tools for the simulation codes for rail vehicle dynamics. This book is the result of the research activities carried out by the Railway Technology Lab of the Department of Mechanical and Aerospace Engineering at Politecnico di Torino. This book presents work on the project for the development of a real-time wheel-rail contact model and provides the simulation results obtained with dSpace real-time hardware. Besides this, the implementation of the contact model for the development of a real-time model for the complex mechatronic system of a scaled test rig is presented in this book and may be useful for the further validation of the real-time contact model with experiments on a full scale test rig.

  17. Extinction time for the contact process on general graphs

    OpenAIRE

    Schapira, Bruno; Valesin, Daniel

    2015-01-01

    We consider the contact process on finite and connected graphs and study the behavior of the extinction time, that is, the amount of time that it takes for the infection to disappear in the process started from full occupancy. We prove, without any restriction on the graph $G$, that if the infection rate $\\lambda$ is larger than the critical rate of the one-dimensional process, then the extinction time grows faster than $\\exp\\{|G|/(\\log|G|)^\\kappa\\}$ for any constant $\\kappa > 1$, where $|G|$...

  18. Attributes for NHDPlus Catchments (Version 1.1)for the Conterminous United States: Contact Time, 2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the average contact time, in units of days, compiled for every catchment of NHDPlus for the conterminous United States. Contact time, as...

  19. Unifying time to contact estimation and collision avoidance across species.

    Directory of Open Access Journals (Sweden)

    Matthias S Keil

    Full Text Available The τ-function and the η-function are phenomenological models that are widely used in the context of timing interceptive actions and collision avoidance, respectively. Both models were previously considered to be unrelated to each other: τ is a decreasing function that provides an estimation of time-to-contact (ttc in the early phase of an object approach; in contrast, g has a maximum before ttc. Furthermore, it is not clear how both functions could be implemented at the neuronal level in a biophysically plausible fashion. Here we propose a new framework--the corrected modified Tau function--capable of predicting both τ-type ("τ(cm" and g-type ("t(mod" responses. The outstanding property of our new framework is its resilience to noise. We show that t(mod can be derived from a firing rate equation, and, as g, serves to describe the response curves of collision sensitive neurons. Furthermore, we show that tcm predicts the psychophysical performance of subjects determining ttc. Our new framework is thus validated successfully against published and novel experimental data. Within the framework, links between τ-type and η-type neurons are established. Therefore, it could possibly serve as a model for explaining the co-occurrence of such neurons in the brain.

  20. Dynamic behavior of polymer surface and the time dependence of contact angle

    Institute of Scientific and Technical Information of China (English)

    WANG Xinping; CHEN Zhifang; SHEN Zhiquan

    2005-01-01

    Time-dependent contact angles were measured by depositing sessile drops of water on the polymer surfaces and monitoring the drop shape as a function of time. It was found that contact angles decreased sharply with contact time and the equilibrium contact angle was finally attained after a certain time. Values of starting (θs) and equilibrium contact angles (θe) obtained by the sessile drop method depend on polymer properties. The Wilhelmy plate technique was used to measure advancing and receding contact angles. The variations of starting (θs) and equilibrium contact angles (θe), advancing (θa) and receding contact angles (θr) have been studied on the oxidized surface of polymers containing polybutadiene block to explore the cause of time-dependence in contact angle measurement and the meaning of θs and θe. The results showed the linear relationships between starting (θs) and advancing contact angles (θa), the equilibrium (θe) and receding contact angles (θr). The similar relationship was also established between the contact angle hysteresis (θa-θr) and differences (θs-θe) in starting contact angles and equilibrium contact angles. Therefore, time-dependence in contact angle measurement was mainly attributed to the surface reconstruction when water drops were deposited on polymer surfaces. The starting contact angle was contributed by the hydrophobic component on polymer surface and the equilibrium contact angle mainly by the hydrophilic component of polymer. These results not only demonstrated the interdependency between two contact angle measurements, the sessile drop method and the Wilhelmy plate technique, but also provided the experimental evidence to explain the cause of time-dependent contact angle. This may also provide a new method to study dynamic behavior of polymer surface.

  1. Supporting Quality Timely PhD Completions: Delivering Research Outcomes

    Science.gov (United States)

    Gasson, Susan

    2015-01-01

    The case study used a three-phase organising process to explain how design and implementation of an accessible and interactive electronic thesis submission form streamlined quality assurance of theses and their timely dissemination via an online thesis repository. The quality of the theses submitted is assured by key academics in their final sign…

  2. Sorption and precipitation of Mn2+ by viable and autoclaved Shewanella putrefaciens: Effect of contact time

    Science.gov (United States)

    Chubar, Natalia; Visser, Tom; Avramut, Cristina; de Waard, Helen

    2013-01-01

    The sorption of Mn(II) by viable and inactivated cells of Shewanella putrefaciens, a non-pathogenic, facultative anaerobic, gram-negative bacterium characterised as a Mn(IV) and Fe(III) reducer, was studied under aerobic conditions, as a function of pH, bacterial density and metal loading. During a short contact time (3-24 h), the adsorptive behaviour of live and dead bacteria toward Mn(II) was sufficiently similar, an observation that was reflected in the studies on adsorption kinetics at various metal loadings, effects of pH, bacteria density, isotherms and drifting of pH during adsorption. Continuing the experiment for an additional 2-30 days demonstrated that the Mn(II) sorption by suspensions of viable and autoclaved cells differed significantly from one another. The sorption to dead cells was characterised by a rapid equilibration and was described by an isotherm. In contrast, the sorption (uptake) to live bacteria exhibited a complex time-dependent uptake. This uptake began as adsorption and ion exchange processes followed by bioprecipitation, and it was accompanied by the formation of polymeric sugars (EPS) and the release of dissolved organic substances. FTIR, EXAFS/XANES and XPS demonstrated that manganese(II) phosphate was the main precipitate formed in 125 ml batches, which is the first evidence of the ability of microbes to synthesise manganese phosphates. XPS and XANES spectra did not detect Mn(II) oxidation. Although the release of protein-like compounds by the viable bacteria increased in the presence of Mn2+ (and, by contrast, the release of carbohydrates did not change), electrochemical analyses did not indicate any aqueous complexation of Mn(II) by the organic ligands.

  3. Sorption and precipitation of Mn2+ by viable and autoclaved Shewanella putrefaciens: Effect of contact time

    KAUST Repository

    Chubar, Natalia

    2013-01-01

    The sorption of Mn(II) by viable and inactivated cells of Shewanella putrefaciens, a non-pathogenic, facultative anaerobic, gram-negative bacterium characterised as a Mn(IV) and Fe(III) reducer, was studied under aerobic conditions, as a function of pH, bacterial density and metal loading. During a short contact time (3-24h), the adsorptive behaviour of live and dead bacteria toward Mn(II) was sufficiently similar, an observation that was reflected in the studies on adsorption kinetics at various metal loadings, effects of pH, bacteria density, isotherms and drifting of pH during adsorption. Continuing the experiment for an additional 2-30days demonstrated that the Mn(II) sorption by suspensions of viable and autoclaved cells differed significantly from one another. The sorption to dead cells was characterised by a rapid equilibration and was described by an isotherm. In contrast, the sorption (uptake) to live bacteria exhibited a complex time-dependent uptake. This uptake began as adsorption and ion exchange processes followed by bioprecipitation, and it was accompanied by the formation of polymeric sugars (EPS) and the release of dissolved organic substances. FTIR, EXAFS/XANES and XPS demonstrated that manganese(II) phosphate was the main precipitate formed in 125ml batches, which is the first evidence of the ability of microbes to synthesise manganese phosphates. XPS and XANES spectra did not detect Mn(II) oxidation. Although the release of protein-like compounds by the viable bacteria increased in the presence of Mn2+ (and, by contrast, the release of carbohydrates did not change), electrochemical analyses did not indicate any aqueous complexation of Mn(II) by the organic ligands. © 2012 Elsevier Ltd.

  4. Self-efficacy is related to PhD completion time: possible tool for interventions

    NARCIS (Netherlands)

    Bouma, Esther

    2015-01-01

    Every two years the University of Groningen evaluates PhD' satisfaction concerning education and working environment. The goal is to create an environment in which PhD's can develop the necessary research skills for their projects as well as finish these projects in time. At Dutch universities most

  5. The effect of pH and time on the extractability and speciation of uranium(VI) sorbed to SiO2.

    Science.gov (United States)

    Ilton, Eugene S; Wang, Zheming; Boily, Jean-François; Qafoku, Odeta; Rosso, Kevin M; Smith, Steven C

    2012-06-19

    The effect of pH and contact time on uranium extractability from quartz surfaces was investigated using either acidic or carbonate (CARB) extraction solutions, time-delayed spikes of different U isotopes ((238)U and (233)U), and liquid helium temperature time-resolved laser-induced fluorescence spectroscopy (TRLFS). Quartz powders were reacted with (238)U(VI) bearing solutions equilibrated with atmospheric CO(2) at pH 6, 7, and 8. After 42 days, the suspensions were spiked with (233)U(VI) and reacted for an additional 7 days. Sorbed U was then extracted with either dilute nitric acid or CARB. For the CARB, but not the acid, extraction there was a systematic decrease in extraction efficiency for both isotopes from pH 6 to 8, which was mimicked by less desorption of (238)U, after the (233)U spike, from pH 6 to 8. The efficiency of (233)U extraction was consistently greater than that of (238)U, indicating a strong temporal component to the strength of U association with the surface that was accentuated with increasing pH. TRLFS revealed a strong correlation between CARB extraction efficiency and sorbed U speciation as a function of pH and time. Collectively, the observations show that aging and pH are critical factors in determining the form and strength of uranium-silica interactions.

  6. Time-domain fluorescence methods as applied to pH sensing

    Science.gov (United States)

    Lippitsch, Max E.; Draxler, Sonja; Leiner, Marc J. P.

    1993-04-01

    Sensors based on luminescence suffer from the fact that during the operating time of the instrument changes in source intensity, light throughput, detector sensitivity, indicator quantum yield, and indicator concentration are inevitable and have to be overcome by extensive referencing and recalibration procedures. Sensors based on luminescence decay time should not suffer from these drawbacks. Decay-time sensing has relied so far on dynamic quenching, which is not well suited for pH measurements. Several other mechanisms are described in this contribution. The conditions necessary for an indicator to be useful in a decay time based pH sensing scheme are clarified and the suitability of this scheme is demonstrated.

  7. Pre-chlorination contact time and the removal and control of Microcystis aeroginosa in coagulation

    Science.gov (United States)

    Lapsongpon, T.; Leungprasert, S.; Yoshimura, C.

    2017-05-01

    The use of pre-oxidation is known to improve algae removal by coagulation and control the growth of algae. The contact time between oxidants and algae in pre-oxidation stage has been found as important parameter. This study investigated the effect of pre-chlorination contact time on the control and removal of cyanobacteria Microcystis aeruginosa by coagulation. The results showed that when the alum dose was sufficient, increasing contact time showed an improvement in algae removal by coagulation in case of high chlorine dose. The algae removal ratio at high chlorine dose, 3 mg L-1 increased when contact time increased and it decreased after 30 minutes of contact time. In contrast, the result from chlorine dose, 2 mg L-1, showed an unclear trend when contact time increased. Adding 2 mg L-1 of pre-chlorination with 10 minutes of contact time was enough to control the regrowth of M. aeruginosa. In addition, dissolve organic carbon (DOC) and UV absorbance at 254 nm, which particulary indicates aromatic compounds, tended to increase when the contact time increased. The increased of DOC and UV 254 indicated the release of intracellular organic matter (IOM) from M. aeruginosa. High level of DOC, 0.68 mg L-1 in this study showed negative effect on M. aeruginosa removal by coagulation and could not be removed by coagulation process.

  8. Real-time visualization of dynamic particle contact failures

    Energy Technology Data Exchange (ETDEWEB)

    Parab, Niranjan D.; Hudspeth, M.; Claus, Benjamin; Guo, Zherui; Sun, Tao; Fezzaa, Kamel; Chen, Weinong W.

    2017-01-01

    Granular materials are widely used to resist impact and blast. Under these dynamic loadings, the constituent particles in the granular system fracture. To study the fracture mechanisms in brittle particles under dynamic compressive loading, a high speed X-ray phase contrast imaging setup was synchronized with a Kolsky bar apparatus. Controlled compressive loading was applied on two contacting particles using the Kolsky bar apparatus and fracture process was captured using the high speed X-ray imaging setup. Five different particles were investigated: soda-lime glass, polycrystalline silica (silicon dioxide), polycrystalline silicon, barium titanate glass, and yttrium stabilized zirconia. For both soda lime glass and polycrystalline silica particles, one of the particles fragmented explosively, thus breaking into many small pieces. For Silicon and barium titanate glass particles, a finite number of cracks were observed in one of the particles causing it to fracture. For yttrium stabilized zirconia particles, a single meridonial crack developed in one of the particles, breaking it into two parts.

  9. Effect of moisture equilibration time and medium on contact angles of bacterial spores.

    Science.gov (United States)

    Eschlbeck, Elisabeth; Kulozik, Ulrich

    2017-04-01

    Contact angle measurement of microorganisms is often described in literature, either to investigate their hydrophobic characteristic or the adhesion behavior of cells. However, in some key aspects the preparation methods differ. Thus, it is difficult to compare results and to choose a procedure for repetition of measurements. The aim of this paper is to point out some critical points during microorganism film preparation that can alter the resulting contact angles. Depending on the moisturizing medium and equilibration time, contact angles differ significantly.

  10. Automated Rain Sampler for Real time pH and Conductivity Measurements

    CERN Document Server

    Weerasinghe, R; Jayananda, M K; Sonnadara, D U J

    2015-01-01

    To monitor the acidity of rain water in real time, a rain water sampling system was developed. The rain sampler detects the initial rain after a dry spell and collects a water sample. Before performing the measurements, the pH probe is calibrated using a standard buffer solution whereas the conductivity probe is calibrated using deionized water. After calibrating the probes the pH and the conductivity of the collected rain water sample are measured using the pH and the conductivity probe. Weather parameters such as air temperature, humidity and pressure are also recorded simultaneously. The pH and conductivity measurement data including weather parameters are transmitted to central station using a GSM modem for further analysis. The collected rain water sample is preserved at the remote monitoring station for post chemical analysis. A programmable logic controller controls the entire process.

  11. Intracerebral pH affects the T2 relaxation time of brain tissue

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, A.M.; Blankenburg, F.B.; Bernarding, J.; Heidenreich, J.O.; Wolf, K.J. [Department of Radiology, University Hospital Benjamin Franklin, Free University Berlin, Hindenburgdamm 30, 12200 Berlin (Germany)

    2002-12-01

    Signal changes in activated brain areas are detectable by MRI and MR spectroscopy (MRS). Shifts in pH occur during brain activation. Our aim was to investigate the relationship between changes in pH and T2 relaxation times. T2 was determined in vitro at 24 MHz in various liquids at different pH using a Carr-Purcell-Meiboom-Gill (CPMG) spin-echo sequence. We also studied five Fisher rats were studied at 2.4 tesla with a double-tuneable surface coil. After baseline measurements, potassium cyanide was injected, producing intracerebral acidosis. Alternating series of 1H CPMG spin-echo sequences and 31P spectra were acquired. True T2 relaxation times were calculated from a CPMG multi-echo train. Changes in intracellular pH determined from 31P spectra. In vitro measurements demonstrated a correlation between T2 and pH that could be described by a quadratic fit curve. Depending on the initial pH, changes of 0.2 induced changes in T2 of up to 150 ms. In vivo measurements confirmed these findings. After intraperitoneal injection of a sublethal dose of cyanide, T2 decreased by about 5% in four cases, followed by recovery after 2 h. The in vitro measurements demonstrated that changes in pH can lead to significant signal change on T2- or T2*- weighted images. The dependence of T2 on pH in vitro was confirmed in vivo; it may contribute to signal change in activated brain areas. (orig.)

  12. The effect of pH, temperature and heating time on inulin chemical stability

    Directory of Open Access Journals (Sweden)

    Paweł Glibowski

    2011-06-01

    Full Text Available Background. Inulin is a storage carbohydrate found in many plants especially in chicory root, Jerusalem artichoke and dahlia tuber. It is a prebiotic with many functional properties. In earlier research concerning chemical stability of inulin, the effect of pH on rheological properties of inulin gels was mainly analysed. In these studies, the effect of time, temperature and pH on inulin chemical stability was not analysed profoundly especially considering the inulin concentrations unable to form gel structure. Thus, the aim of this work was to study the effect of the above mentioned factors on inulin chemical stability in water solution. Material and methods. 5% (w/w inulin solutions at pH 1-12 were heated at 20, 40, 60, 80 and 100°C for 5-60 min. After the neutralisation the content of reducing sugar was analysed according to Miller’s method (1959 with 3,5-dinitrosalicylic acid. Results. The conducted studies showed that inulin chemical stability at pH £ 4 decreased with an increase of heating time and temperature. In a neutral and basic environment inulin was chemically stable regardless of heating time and temperature. Conclusions. Inulin application in food systems may be limited in acidic products especially when heated above 60°C during the production process. However, in products at pH ≥ 5, the degradation of this fructan does not occur even at thermal processing.

  13. Real-time feedback control of pH within microfluidics using integrated sensing and actuation.

    Science.gov (United States)

    Welch, David; Christen, Jennifer Blain

    2014-03-21

    We demonstrate a microfluidic system which applies engineering feedback principles to control the pH of a solution with a high degree of precision. The system utilizes an extended-gate ion-sensitive field-effect transistor (ISFET) along with an integrated pseudo-reference electrode to monitor pH values within a microfluidic reaction chamber. The monitored reaction chamber has an approximate volume of 90 nL. The pH value is controlled by adjusting the flow through two input channels using a pulse-width modulated signal applied to on-chip integrated valves. We demonstrate real-time control of pH through the feedback-controlled stepping of 0.14 pH increments in both the increasing and decreasing direction. The system converges to the pH setpoint within approximately 20 seconds of a step change. The integration of feedback theory into a microfluidic environment is a necessary step for achieving complete control over the microenvironment.

  14. Phosphoproteomics analysis of postmortem porcine muscle with pH decline rate and time difference

    DEFF Research Database (Denmark)

    Huang, Honggang; Larsen, Martin R; Karlsson, Anders H

    2012-01-01

    The aim of this study was to characterize the protein phosphorylation in postmortem (PM) muscle and reveal the change during meat quality development. The gel-based phosphoproteomic analysis of PM porcine muscle was performed in three pig groups with different pH decline rates from PM 1h to 24 h...... the reverse case. The phosphorylation level of 12 bands in sarcoplasmic fraction and 3 bands in myofibrillar fraction were significantly affected by the synergy effects of pH and time (pproteins were identified. The phosphorylation patterns of pyruvate kinase, triosephosphate isomerase-1......, tropomyosin and myosin regulatory light chain 2 showed to be related to PM muscle pH decline rate and time. Our work sheds light on the potential role of protein phosphorylation on regulation of meat quality development....

  15. Time-domain measurement of fluorescence lifetime variation with pH

    Science.gov (United States)

    Ryder, Alan G.; Power, Sarah; Glynn, Thomas J.; Morrison, John J.

    2001-07-01

    Advances in the design and miniaturization of the lasers and electronics required for Time Correlated Single Photon Counting (TCSPC) measurement of fluorescence lifetime have simplified the use of the time domain method. We have assembled a compact portable system that is capable of measuring lifetimes down to approximately 200 ps (with deconvolution) and that can operate at a range of excitation and emission wavelengths. The excitation sources are pulsed LEDs and laser diodes with a maximum pulse rate of 40 MHz and are easily interchanged. Furthermore, the development of violet and blue GaN LEDs and laser diodes is expanding the range of fluorophores available for fluorescence lifetime measurement of ion concentrations. pH sensitive fluorophores have a wide range of biological and clinical applications. The use of fluorescence lifetime rather than intensity to measure pH has a number of advantages including the reduction of effects due to the photobleaching, scattering, and intensity variations in the excitation source. Using our compact TCSPC instrumentation we have measured the dependence of fluorescence lifetimes on pH for a range of dyes in phosphate buffer over the physiologically important range of 6.0 to 8.0. Most dyes exhibit only a small variation in lifetime (pH range; however, acridine exhibits a large variation in lifetime and hence shows promise as a pH indicator.

  16. Predicting the "graduate on time (GOT)" of PhD students using binary logistics regression model

    Science.gov (United States)

    Shariff, S. Sarifah Radiah; Rodzi, Nur Atiqah Mohd; Rahman, Kahartini Abdul; Zahari, Siti Meriam; Deni, Sayang Mohd

    2016-10-01

    Malaysian government has recently set a new goal to produce 60,000 Malaysian PhD holders by the year 2023. As a Malaysia's largest institution of higher learning in terms of size and population which offers more than 500 academic programmes in a conducive and vibrant environment, UiTM has taken several initiatives to fill up the gap. Strategies to increase the numbers of graduates with PhD are a process that is challenging. In many occasions, many have already identified that the struggle to get into the target set is even more daunting, and that implementation is far too ideal. This has further being progressing slowly as the attrition rate increases. This study aims to apply the proposed models that incorporates several factors in predicting the number PhD students that will complete their PhD studies on time. Binary Logistic Regression model is proposed and used on the set of data to determine the number. The results show that only 6.8% of the 2014 PhD students are predicted to graduate on time and the results are compared wih the actual number for validation purpose.

  17. Workers' compensation loss prevention representative contact and risk of lost-time injury in construction policyholders.

    Science.gov (United States)

    Schofield, Katherine E; Alexander, Bruce H; Gerberich, Susan G; MacLehose, Richard F

    2017-09-01

    Insurance loss prevention (LP) representatives have access and contact with businesses and employees to provide targeted safety and health resources. Construction firms, especially those smaller in size, are a high-risk population. This research evaluated the association between LP rep contact and risk for lost-time injuries in construction policyholders. Workers' compensation data were utilized to track LP rep contact with policyholders and incidence of lost-time injury over time. Survival analysis with repeated events modeling calculated hazard ratios (HR) and 95% confidence intervals (CI). Compared no LP contact, one contact was associated with a 27% reduction of risk (HR=0.73, CI=0.65-0.82), two with a 41% (HR=0.59, CI=0.51-0.68), and three or more contacts with a 28% reduction of risk (HR=0.72, CI=0.65-0.81). LP reps appear to be a valuable partner in efforts to reduce injury burden. Their presence or contact with policyholders is consistent with reduction in overall incidence of lost-time injuries. Reduction in lost-time injuries, resulting in reduced workers' compensation costs for policyholders and insurance companies, builds a business-case for safety and injury prevention. LP reps are often a low or no-cost benefit for insurance policyholders and may be an important injury prevention resource for small firms and/or those with lack of safety resources and staff. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Factors Affecting Timely Completion of a PhD: A Complex Systems Approach

    Science.gov (United States)

    Pitchforth, Jegar; Beames, Stephanie; Thomas, Aleysha; Falk, Matthew; Farr, Charisse; Gasson, Susan; Thamrin, Sri Astuti; Mengersen, Kerrie

    2012-01-01

    Completing a PhD on time is a complex process, influenced by many interacting factors. In this paper we take a Bayesian Network approach to analyzing the factors perceived to be important in achieving this aim. Focusing on a single research group in Mathematical Sciences, we develop a conceptual model to describe the factors considered to be…

  19. Contact frequency, travel time, and travel costs for patients with rheumatoid arthritis

    DEFF Research Database (Denmark)

    Sørensen, Jan; Linde, Louise; Hetland, Merete Lund

    2014-01-01

    across Denmark recruited patients to the study. Data collected included frequency, travel time and travel costs for contacts at rheumatology outpatient clinics, other outpatient clinics, general practitioners, privately practicing medical specialists, inpatient hospitals and accident and emergency...

  20. Micro Electrochemical pH Sensor Applicable for Real-Time Ratiometric Monitoring of pH Values in Rat Brains.

    Science.gov (United States)

    Zhou, Jie; Zhang, Limin; Tian, Yang

    2016-02-16

    To develop in vivo monitoring meter for pH measurements is still the bottleneck for understanding the role of pH plays in the brain diseases. In this work, a selective and sensitive electrochemical pH meter was developed for real-time ratiometric monitoring of pH in different regions of rat brains upon ischemia. First, 1,2-naphthoquinone (1,2-NQ) was employed and optimized as a selective pH recognition element to establish a 2H(+)/2e(-) approach over a wide range of pH from 5.8 to 8.0. The pH meter demonstrated remarkable selectivity toward pH detection against metal ions, amino acids, reactive oxygen species, and other biological species in the brain. Meanwhile, an inner reference, 6-(ferrocenyl)hexanethiol (FcHT), was selected as a built-in correction to avoid the environmental effect through coimmobilization with 1,2-NQ. In addition, three-dimensional gold nanoleaves were electrodeposited onto the electrode surface to amplify the signal by ∼4.0-fold and the measurement was achieved down to 0.07 pH. Finally, combined with the microelectrode technique, the microelectrochemical pH meter was directly implanted into brain regions including the striatum, hippocampus, and cortex and successfully applied in real-time monitoring of pH values in these regions of brain followed by global cerebral ischemia. The results demonstrated that pH values were estimated to 7.21 ± 0.05, 7.13 ± 0.09, and 7.27 ± 0.06 in the striatum, hippocampus, and cortex in the rat brains, respectively, in normal conditions. However, pH decreased to 6.75 ± 0.07 and 6.52 ± 0.03 in the striatum and hippocampus, upon global cerebral ischemia, while a negligible pH change was obtained in the cortex.

  1. The Effect of pH and Time on The Stability of Superparamagnetic Maghemite Nanoparticle Suspensions

    Directory of Open Access Journals (Sweden)

    Nurdin Irwan

    2016-01-01

    Full Text Available Maghemite (γ-Fe2O3 nanoparticles have been synthesized using a chemical co-precipitation method. The morphology and particle size is characterized using Transmission Electron Microscopy (TEM, and magnetic characterization using Alternating Gradient Magnetometry (AGM. The stability of the maghemite nanoparticles suspension were studied at different pH and time of storage. Dynamic Light Scattering (DLS and Zeta Potential were conducted to determine the stability of the suspensions. TEM observation showed that the particles size is 9.6 nm and have spherical morphology. The particles showed superparamagnetic behavior with saturation magnetization 25.5 emu/g. The suspensions are stable in the acidic condition at pH 4 and alkaline condition at pH 10. The suspensions remain stable after 4 weeks of storage.

  2. Time dependent FTIR spectra of mineral waters after contact with air

    CERN Document Server

    Kondyurin, Alexey

    2010-01-01

    FTIR spectra of mineral waters of Slavyanovskaya, Aqua Montana, Bad Harzburger and Christinen with time from first contact of water with open air were analysed. The kinetic of spectral changes of Slavyanovskaya mineral water in the regions of stretch, deformation and intermolecular vibrations was measured. The spectral changes do not correlate with chemical contamination of mineral water and degassing process. The observed spectral changes could be due to different structure of mineral water in liquid state, which is destroyed after air contact. The observed spectral behaviour of Slavyanovskaya is correlated with the catalytic activity of mineral water, which was saved without contact with air. The characteristic time of spectral dependence (669 seconds) is close to the characteristic time of catalytic activity loss (600 seconds) of mineral water at air contact. The spectra results support the medical studies that show the activity of mineral water near spring, and the loosing activity of water after long tim...

  3. Relationship between Wetting Hysteresis and Contact Time of a Bouncing Droplet on Hydrophobic Surfaces.

    Science.gov (United States)

    Shen, Yizhou; Tao, Jie; Tao, Haijun; Chen, Shanlong; Pan, Lei; Wang, Tao

    2015-09-23

    The contact time of impacting water droplets on superhydrophobic surfaces directly reflects the extent of thermal and energy conversions between the water droplet and the surface, which is also considered to be crucial to the practical applications. The purpose of this study was to reveal the relationship between the contact time and the wetting hysteresis. We designed and fabricated six classes of surfaces with different extent of hydrophobicity through modifying the microscale/nanoscale hierarchical textured titanium surfaces with 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, and we filmed the contact process of the water droplet impacting on these surfaces using a high-speed camera. It can be concluded that wetting hysteresis played a significant role in determining how long the impacting water droplet can bounce off the surface, based on the interfacial wetting mechanism and the work done against the resistance force generated by contact angle hysteresis during the dynamic process.

  4. Inactivation of Mold Spores from Moist Carpet Using Steam Vapor: Contact Time and Temperature.

    Science.gov (United States)

    Ong, Kee-Hean; Emo, Brett; Lewis, Roger D; Kennedy, Jason; Thummalakunta, Laxmi N A; Elliott, Michael

    2015-01-01

    Steam vapor has been shown to reduce viable mold spores in carpet, but the minimal effective temperature and contact time has not been established. This study evaluated the effectiveness of steam vapor in reducing the number of viable mold spores in carpet as a function of temperature and contact time. Seventy carpet samples were inoculated with a liquid suspension of Cladosporium sphaerospermum and incubated over a water-saturated foam carpet pad for 24 hr. Steam was applied to the samples as the temperature was measured from the carpet backing. Contact time was closely monitored over seven time intervals: 0, 2, 4, 8, 12, 16, and 20 sec. Following steam vapor treatment, mold spores were extracted from the carpet samples and the extract was plated on DG-18 plates at 1:1, 1:10, 1:100 dilutions followed by one week of incubation. Raw colony forming units were determined using an automated colony counter and adjusted based on dilution factor, extraction volume, and plated volume. Analysis of variance and linear regression were used to test for statistically significant relationships. Steam contact time exhibited a linear relationship to observed temperature of carpet backing (F = 90.176, R(2) = 0.609). Observed temperature of carpet backing had a positive relationship to percent reduction of mold (F = 76.605, R(2) = 0.569). Twelve seconds of steam vapor contact time was needed to achieve over 90% mold reduction on moist carpet.

  5. Time reversal invariance for a one-dimensional model of contact acoustic nonlinearity

    Science.gov (United States)

    Blanloeuil, Philippe; Francis Rose, L. R.; Veidt, Martin; Wang, Chun H.

    2017-04-01

    The interaction of a one-dimensional (1D) wave packet with a contact interface characterized by a unilateral contact law is investigated analytically and through a finite difference model. It is shown that this interaction leads to the generation of higher harmonic, sub-harmonic and zero-frequency components in the reflected wave, resulting in a pulse distortion that is attributable to contact acoustic nonlinearity. However, the results also show that the re-emission of a time reversed version of this distorted first reflection results in a healing of the distortions and a perfect recovery of the original pulse shape, thereby demonstrating time reversal invariance for this type of contact acoustic nonlinearity. A step-by-step analysis of the contact interaction provides insights into both the distortion arising from the first interaction and the subsequent healing during the second interaction. These findings suggest that time reversal invariance should also apply more generally for scatterers exhibiting non-dissipative contact acoustic nonlinearity.

  6. Doubly Exponential Solution for Randomized Load Balancing Models with Markovian Arrival Processes and PH Service Times

    CERN Document Server

    Li, Quan-Lin

    2010-01-01

    In this paper, we provide a novel matrix-analytic approach for studying doubly exponential solution of randomized load balancing models (also known as the supermarket models) with Markovian arrival processes (MAPs) and PH service times. We describe the supermarket model as a system of differential vector equations, and obtain a close-form solution: doubly exponential structure, for the fixed point of the system of differential vector equations. Based on this, we show that the fixed point is decomposited into two groups of information under a product form: the arrival information and the service information, and indicate that the doubly exponential solution to the fixed point is not always unique for more general supermarket models. Furthermore, we analyze the exponential convergence of the current location of the supermarket model to its fixed point, and study the Lipschitz condition in the Kurtz Theorem under MAP arrivals and PH service times. This paper gains a new understanding how the workload probing can...

  7. Doubly Exponential Solution for Randomized Load Balancing Models with Markovian Arrival Processes and PH Service Times

    OpenAIRE

    Li,Quan-Lin; Lui, John C. S.

    2010-01-01

    In this paper, we provide a novel matrix-analytic approach for studying doubly exponential solutions of randomized load balancing models (also known as supermarket models) with Markovian arrival processes (MAPs) and phase-type (PH) service times. We describe the supermarket model as a system of differential vector equations by means of density dependent jump Markov processes, and obtain a closed-form solution with a doubly exponential structure to the fixed point of the system of differential...

  8. Doubly Exponential Solution for Randomized Load Balancing Models with Markovian Arrival Processes and PH Service Times

    OpenAIRE

    Li, Quan-Lin; Lui, John C. S.

    2010-01-01

    In this paper, we provide a novel matrix-analytic approach for studying doubly exponential solutions of randomized load balancing models (also known as supermarket models) with Markovian arrival processes (MAPs) and phase-type (PH) service times. We describe the supermarket model as a system of differential vector equations by means of density dependent jump Markov processes, and obtain a closed-form solution with a doubly exponential structure to the fixed point of the system of differential...

  9. Effect of Contact Time Between Silicone Impression Materials and Stone on Dimensional Stability of Resultant Cast

    Directory of Open Access Journals (Sweden)

    Heidari

    2013-06-01

    Full Text Available Background Numerous factors have an effect on the accuracy of an impression and resultant cast, and these include: impression material, impression technique, tray selection, impression disinfection, storage time of impression before pouring, stone type used for fabrication of cast. Up to now, there has been little research conducted on the effect of contact time of a cast with an impression, on the dimensional stability of a cast. Objectives The purpose of this study was to evaluate the effect of the contact time of silicone impression materials with stone casts, on the dimensional stability of resultant casts. Materials and Methods A total of 44 impressions were made from a stainless steel master model, with each one of two silicone impression materials (Elite HD+ and Speedex, and poured with Elite Master Type IV. The thickness of the light-body material (1 mm was provided by using four copings. The resulting casts from each material were placed in four groups(n = 11 after each contact time with the impression (1 hour, 24 hours, 48 hours, 1 week. Distance between anterior and posterior abutments was measured for the casts and master model. Data were analyzed by two-way analysis of variance and a Tukey test. Results The relationship between the dimensional stability of the casts and the simultaneous effect of the impression material and contact time of the cast with the impression was not statistically significant (P = 0.099. Type of impression material on the dimensional stability of the cast had no significant effect (P = 0.163. Increased contact time of the cast with the impression resulted in increased dimensional change (P < 0.001. Conclusions Dimensional stability of the casts after different contact time with the impression was acceptable. The best time to separate the cast from the impression was one hour after pouring the impression.

  10. Does the contact time of alginate with plaster cast influence its properties?

    Directory of Open Access Journals (Sweden)

    Mariana Marquezan

    2012-06-01

    Full Text Available The aim of this study was to verify the influence of the time of contact between alginate and gypsum after the modeling procedure on the properties of the plaster cast, such as surface detail, dimensional stability and microhardness. Thirty cylindrical specimens of orthodontic gypsum Type III were made by means of impressions of a stainless steel master model which had five reference lines in the upper surface. The samples were divided into two groups: Group 1 (G1 - with time of contact of 1 hour; and Group 2 (G2 - 12 hours of contact. All the specimens were stored up to 48 hours until they underwent laboratory testing. Surface detail and dimensional stability were tested by one calibrated examiner using a visual analysis and a profilometer (Profile Projector Nikon model 6C, Nikon Corporation, Tokyo, Japan, respectively, to evaluate the quality of reproduction of the lines and the distances between them. The microhardness was determined for each sample by making six indentations with a Vickers diamond pyramid indenter (Buehler, Lake Bluff, USA under a load of 100 gF for 15 s. The results showed significant difference (P £ 0.05 between groups in two of the three properties examined: surface detail and microhardness, which decreased as the time of contact rose. The 12-hour time of contact between alginate and the plaster cast is not recommended because it influences the quality of the plaster cast.

  11. Does the contact time of alginate with plaster cast influence its properties?

    Directory of Open Access Journals (Sweden)

    Mariana Marquezan

    Full Text Available The aim of this study was to verify the influence of the time of contact between alginate and gypsum after the modeling procedure on the properties of the plaster cast, such as surface detail, dimensional stability and microhardness. Thirty cylindrical specimens of orthodontic gypsum Type III were made by means of impressions of a stainless steel master model which had five reference lines in the upper surface. The samples were divided into two groups: Group 1 (G1 - with time of contact of 1 hour; and Group 2 (G2 - 12 hours of contact. All the specimens were stored up to 48 hours until they underwent laboratory testing. Surface detail and dimensional stability were tested by one calibrated examiner using a visual analysis and a profilometer (Profile Projector Nikon model 6C, Nikon Corporation, Tokyo, Japan, respectively, to evaluate the quality of reproduction of the lines and the distances between them. The microhardness was determined for each sample by making six indentations with a Vickers diamond pyramid indenter (Buehler, Lake Bluff, USA under a load of 100 gF for 15 s. The results showed significant difference (P £ 0.05 between groups in two of the three properties examined: surface detail and microhardness, which decreased as the time of contact rose. The 12-hour time of contact between alginate and the plaster cast is not recommended because it influences the quality of the plaster cast.

  12. Time-related contact angle measurements with human plasma on biomaterial surfaces

    NARCIS (Netherlands)

    Rakhorst, G; Van der Mei, HC; Van Oeveren, W; Spijker, HT; Busscher, HJ

    1999-01-01

    Axisymmetric drop shape analysis by profile (ADSA-P) was used to assess in time contact angle changes of human plasma drops placed on four different biomaterials. Results were related with conventional blood compatibility measurements: albumin adsorption, fibrinogen adsorption and platelet adhesion.

  13. Monitoring anaerobic sequential batch reactors via fractal analysis of pH time series.

    Science.gov (United States)

    Méndez-Acosta, H O; Hernandez-Martinez, E; Jáuregui-Jáuregui, J A; Alvarez-Ramirez, J; Puebla, H

    2013-08-01

    Efficient monitoring and control schemes are mandatory in the current operation of biological wastewater treatment plants because they must accomplish more demanding environmental policies. This fact is of particular interest in anaerobic digestion processes where the availability of accurate, inexpensive, and suitable sensors for the on-line monitoring of key process variables remains an open problem nowadays. In particular, this problem is more challenging when dealing with batch processes where the monitoring strategy has to be performed in finite time, which limits the application of current advanced monitoring schemes as those based in the proposal of nonlinear observers (i.e., software sensors). In this article, a fractal time series analysis of pH fluctuations in an anaerobic sequential batch reactor (AnSBR) used for the treatment of tequila vinasses is presented. Results indicated that conventional on-line pH measurements can be correlated with off-line determined key process variables, such as COD, VFA and biogas production via some fractality indexes.

  14. Design and Modeling of a Flexible Contact-Mode Piezoresistive Detector for Time-Based Acceleration Sensing

    NARCIS (Netherlands)

    Rajaraman, V.; Hau, B.S.; Rocha, L.A.; French, P.J.; Makinwa, K.A.A.

    2010-01-01

    This work reports on the design and modeling of a new flexible contact-mode 1-DOF piezoresistive contact force and impacttime detector used for acceleration sensing in the time domain. The key advantages of the contact-mode detection mechanism are the use of simple readout circuitry, compactness,

  15. Design and Modeling of a Flexible Contact-Mode Piezoresistive Detector for Time-Based Acceleration Sensing

    NARCIS (Netherlands)

    Rajaraman, V.; Hau, B.S.; Rocha, L.A.; French, P.J.; Makinwa, K.A.A.

    2010-01-01

    This work reports on the design and modeling of a new flexible contact-mode 1-DOF piezoresistive contact force and impacttime detector used for acceleration sensing in the time domain. The key advantages of the contact-mode detection mechanism are the use of simple readout circuitry, compactness, go

  16. Real-time measurement and interpretation of the conductivity and pH of precipitation samples

    Energy Technology Data Exchange (ETDEWEB)

    Beverland, I.J.; Heal, M.R.; Crowther, J.M.; Srinivas, M.S.N. [University of Edinburgh, Edinburgh (United Kingdom). Dept. of Public Health Sciences

    1997-09-01

    A microprocessor-based acid mine monitor was used to make real-time measurements of conductivity and pH of rainwater within individual storms. The automated measurements were compared with laboratory analyses of a subset of the samples taken. The laboratory measurements tended to overestimate the pH because of temperature induced changes in dissociation and Henry`s Law constants affecting ionic compounds in the rainwater. The measurement artefact due to these effects may result in average hydrogen ion concentrations being underestimated by approximately 10 to 15% at UK sites. The greatest systematic discrepancies would be anticipated at highly polluted sites and during low temperatures acidic episodes. The concept of a rainwater acid fraction was investigated and found to useful for quality control and interpretative purposes. The field measurement of conductivity of low ionic strength samples was slightly lower than the corresponding laboratory measurement, possibly caused by limited resolution of the conductivity probe or dissolution of fine particulate material. 38 refs., 8 figs., 1 tab.

  17. Subjective well-being and time use of brazilian PhD professors

    Directory of Open Access Journals (Sweden)

    Maiana Farias Oliveira Nunes

    2014-12-01

    Full Text Available The university professor suffers high pressure to achieve productivity and performs under work conditions that are not always satisfactory. This study seeks to analyze the subjective well-being, the time-use strategies, and the satisfaction with their use of time of PhD-holding professors with and without productivity grants from the National Council for Scientific and Technological Development (CNPq. A total of 83 professors participated in the study (48 with productivity grants, with an average age of 50 years. A total of 89% of participants were from public institutions. The majority of the participants exhibited high levels of negative affect and low-average levels of satisfaction with their use of time. There was no difference in the subjective well-being or in the satisfaction with the use of time when comparing professors who had received a CNPq grant with professors who had not received a CNPq grant. The most important reason for dissatisfaction with the use of time was an excess of work, whereas peer recognition was the primary achievement obtained with the work. How work demands and conditions influence the well-being of the professors is discussed in this study.

  18. Participant observation of time allocation, direct patient contact and simultaneous activities in hospital physicians

    Directory of Open Access Journals (Sweden)

    Zupanc Andrea

    2009-06-01

    Full Text Available Abstract Background Hospital physicians' time is a critical resource in medical care. Two aspects are of interest. First, the time spent in direct patient contact – a key principle of effective medical care. Second, simultaneous task performance ('multitasking' which may contribute to medical error, impaired safety behaviour, and stress. There is a call for instruments to assess these aspects. A preliminary study to gain insight into activity patterns, time allocation and simultaneous activities of hospital physicians was carried out. Therefore an observation instrument for time-motion-studies in hospital settings was developed and tested. Methods 35 participant observations of internists and surgeons of a German municipal 300-bed hospital were conducted. Complete day shifts of hospital physicians on wards, emergency ward, intensive care unit, and operating room were continuously observed. Assessed variables of interest were time allocation, share of direct patient contact, and simultaneous activities. Inter-rater agreement of Kappa = .71 points to good reliability of the instrument. Results Hospital physicians spent 25.5% of their time at work in direct contact with patients. Most time was allocated to documentation and conversation with colleagues and nursing staff. Physicians performed parallel simultaneous activities for 17–20% of their work time. Communication with patients, documentation, and conversation with colleagues and nursing staff were the most frequently observed simultaneous activities. Applying logit-linear analyses, specific primary activities increase the probability of particular simultaneous activities. Conclusion Patient-related working time in hospitals is limited. The potential detrimental effects of frequently observed simultaneous activities on performance outcomes need further consideration.

  19. Immunization strategies for epidemic processes in time-varying contact networks

    CERN Document Server

    Starnini, Michele; Cattuto, Ciro; Barrat, Alain; Satorras, Romualdo Pastor

    2013-01-01

    Spreading processes represent a very efficient tool to investigate the structural properties of networks and the relative importance of their constituents, and have been widely used to this aim in static networks. Here we consider simple disease spreading processes on empirical time-varying networks of contacts between individuals, and compare the effect of several immunization strategies on these processes. An immunization strategy is defined as the choice of a set of nodes (individuals) who cannot catch nor transmit the disease. This choice is performed according to a certain ranking of the nodes of the contact network. We consider various ranking strategies, focusing in particular on the role of the training window during which the nodes' properties are measured in the time-varying network: longer training windows correspond to a larger amount of information collected and could be expected to result in better performances of the immunization strategies. We find instead an unexpected saturation in the effic...

  20. Finite-time singularities in the dynamical evolution of contact lines

    CERN Document Server

    Pelinovsky, D E

    2013-01-01

    We study finite-time singularities in the linear advection-diffusion equation with a variable speed on a semi-infinite line. The variable speed is determined by an additional condition at the boundary, which models the dynamics of a contact line of a hydrodynamic flow at a 180 contact angle. Using apriori energy estimates, we derive conditions on variable speed that guarantee that a sufficiently smooth solution of the linear advection--diffusion equation blows up in a finite time. Using the class of self-similar solutions to the linear advection-diffusion equation, we find the blow-up rate of singularity formation. This blow-up rate does not agree with previous numerical simulations of the model problem.

  1. Inhibitory Concentration and Minimum Contact Time Gambir Extract (Uncaria gambier Roxb Against Bacterial Growth Enterococcus faecalis

    Directory of Open Access Journals (Sweden)

    Hafsah Katu

    2016-06-01

    Full Text Available Enterococcus faecalis (E.Faecalis gram-positive bacteria commonly found in endodontic retreatment cases. Extract Gambir, a type of dried sap from the leaves and young stems of plants gambier (Uncaria gambier Roxb contains catechins, which are potent antibacterial and anti fungal with minimal side effects. This study aimed to determine the inhibitory concentrations and minimal contact time Gambir extract on the growth of the bacteria E. faecalis. Research applied a design with lab experiments, conducted on May 30-June 16, 2011 at the Laboratory of Pharmacognosy-Phytochemicals Faculty of Pharmacy and Laboratory of Microbiology, Faculty of Medicine, University of Hasanuddin. Materials and methods; 600 gr Gambir which has been crushed, extracted with reflux and rotary method. Minimal Inhibitory Concentration is determined with 5 ml of 5.25% NaOCl as a positive control and sterile distilled water negative control. Antibacterial activity is determined based on the time zone diameter hambat.Analisis contact and SPSS version 16.0 for windows with One-way ANOVA test and LSD on (p <0.05. Results indicated that Statistical analysis showed a 1% concentration and contact time of 24 hours, effectively inhibits the growth of bacteria E.faecalis. in conclusion, Gambir extract effectively inhibits the growth of bacteria E. faecalis.

  2. Blink patterns and lid-contact times in dry-eye and normal subjects

    Directory of Open Access Journals (Sweden)

    Ousler GW 3rd

    2014-05-01

    Full Text Available George W Ousler 3rd,1 Mark B Abelson,1,2 Patrick R Johnston,1 John Rodriguez,1 Keith Lane,1 Lisa M Smith11Ora, Andover, MA, USA; 2Department of Ophthalmology, Harvard Medical School, Boston, MA, USAPurpose: To classify blinks in dry eye and normal subjects into six subtypes, and to define the blink rate and duration within each type of blink, as well as the total lid-contact time/minute.Materials and methods: This was a single-centered, prospective, double-blind study of eleven dry-eye and ten normal subjects. Predefined subjects watched a video while blinks were recorded for 10 minutes. Partial blinks were classified by percentage closure of maximal palpebral fissure opening: 25%, 50%, 75%. Complete blinks were characterized as full (>0 seconds, extended (>0.1 seconds, or superextended (>0.5 seconds. The mean duration of each type of blink was determined and standardized per minute as total lid-contact time.Results: Total blinks observed were 4,990 (1,414 normal, 3,756 dry eye: 1,809 (50.59% partial and 1,767 (49.41% complete blinks among dry-eye subjects versus 741 (52.90% partial and 673 (47.60% complete blinks among normal subjects. Only superextended blinks of ≥0.5-second duration were significantly more frequent in dry-eye subjects than normals (2.3% versus 0.2%, respectively; P=0.023. Total contact time was seven times higher in dry-eye subjects than normals (0.565 versus 0.080 seconds, respectively; P<0.001. Isolating only extended blinks (>0.1 second, the average contact time (seconds was four times longer in dry-eye versus normal subjects (2.459 in dry eye, 0.575 in normals; P=0.003. Isolating only superextended blinks (>0.5 seconds, average contact time was also significantly different (7.134 in dry eye, 1.589 in normals; P<0.001. The contact rate for all full closures was 6.4 times longer in dry-eye (0.045 versus 0.007, P<0.001 than normal subjects.Conclusion: Dry-eye subjects spent 4.5% of a

  3. Aging of nickel added to soils as predicted by soil pH and time.

    Science.gov (United States)

    Ma, Yibing; Lombi, Enzo; McLaughlin, Mike J; Oliver, Ian W; Nolan, Annette L; Oorts, Koen; Smolders, Erik

    2013-08-01

    Although aging processes are important in risk assessment for metals in soils, the aging of Ni added to soils has not been studied in detail. In this study, after addition of water soluble Ni to soils, the changes over time in isotopic exchangeability, total concentrations and free Ni(2+) activity in soil pore water, were investigated in 16 European soils incubated outdoors for 18 months. The results showed that after Ni addition, concentrations of Ni in soil pore water and isotopic exchangeability of Ni in soils initially decreased rapidly. This phase was followed by further decreases in the parameters measured but these occurred at slower rates. Increasing soil pH increased the rate and extent of aging reactions. Semi-mechanistic models, based on Ni precipitation/nucleation on soil surfaces and micropore diffusion, were developed and calibrated. The initial fast processes, which were attributed to precipitation/nucleation, occurred over a short time (e.g. 1h), afterwards the slow processes were most likely controlled by micropore diffusion processes. The models were validated by comparing predicted and measured Ni aging in three additional, widely differing soils aged outdoors for periods up to 15 months in different conditions. These models could be used to scale ecotoxicological data generated in short-term studies to longer aging times.

  4. Surface contact stimulates the just-in-time deployment of bacterial adhesins.

    Science.gov (United States)

    Li, Guanglai; Brown, Pamela J B; Tang, Jay X; Xu, Jing; Quardokus, Ellen M; Fuqua, Clay; Brun, Yves V

    2012-01-01

    The attachment of bacteria to surfaces provides advantages such as increasing nutrient access and resistance to environmental stress. Attachment begins with a reversible phase, often mediated by surface structures such as flagella and pili, followed by a transition to irreversible attachment, typically mediated by polysaccharides. Here we show that the interplay between pili and flagellum rotation stimulates the rapid transition between reversible and polysaccharide-mediated irreversible attachment. We found that reversible attachment of Caulobacter crescentus cells is mediated by motile cells bearing pili and that their contact with a surface results in the rapid pili-dependent arrest of flagellum rotation and concurrent stimulation of polar holdfast adhesive polysaccharide. Similar stimulation of polar adhesin production by surface contact occurs in Asticcacaulis biprosthecum and Agrobacterium tumefaciens. Therefore, single bacterial cells respond to their initial contact with surfaces by triggering just-in-time adhesin production. This mechanism restricts stable attachment to intimate surface interactions, thereby maximizing surface attachment, discouraging non-productive self-adherence, and preventing curing of the adhesive.

  5. Application of RANS Simulations for Contact Time Predictions in Turbulent Reactor Tanks for Water Purification Process

    Science.gov (United States)

    Nickles, Cassandra; Goodman, Matthew; Saez, Jose; Issakhanian, Emin

    2016-11-01

    California's current drought has renewed public interest in recycled water from Water Reclamation Plants (WRPs). It is critical that the recycled water meets public health standards. This project consists of simulating the transport of an instantaneous conservative tracer through the WRP chlorine contact tanks. Local recycled water regulations stipulate a minimum 90-minute modal contact time during disinfection at peak dry weather design flow. In-situ testing is extremely difficult given flowrate dependence on real world sewage line supply and recycled water demand. Given as-built drawings and operation parameters, the chlorine contact tanks are modeled to simulate extreme situations, which may not meet regulatory standards. The turbulent flow solutions are used as the basis to model the transport of a turbulently diffusing conservative tracer added instantaneously to the inlet of the reactors. This tracer simulates the transport through advection and dispersion of chlorine in the WRPs. Previous work validated the models against experimental data. The current work shows the predictive value of the simulations.

  6. Time-to-Fatigue and Intramuscular pH measured via NIRS during Handgrip Exercise in Trained and Sedentary Individuals

    Science.gov (United States)

    Everett, M. E.; Lee, S. M. C.; Stroud, L.; Scott, P.; Hagan, R. D.; Soller, B.R.

    2009-01-01

    In exercising muscles force production and muscular endurance are impaired by a decrease in intramuscular pH. The effects of aerobic training (AT) on preventing acidosis and prolonging exercise time in muscles not specifically targeted by the training are unknown. Purpose: To compare interstitial pH, measured non-invasively with near infrared spectroscopy (NIRS), in the flexor digitorum profundus (FDP) during rhythmic handgrip exercise in sedentary subjects and those who participate in AT activities that target the lower body. Methods: Maximal isometric force (MIF) was measured on three separate days in AT (n=5) and sedentary (n=8) subjects using a handgrip dynamometer (HGD). Isometric muscular endurance (IME) was measured during five trials, each separated by at least 48 hrs. For each IME trial subjects rhythmically squeezed (4 sec at 40% of MVC) and relaxed (2 sec) to fatigue or failure to reach the target force in three consecutive contractions or four non-consecutive contractions. Interstitial pH was derived from spectra collected using a NIRS sensor adhered to the skin over the FDP. The first four IME trials served to familiarize subjects with the protocol; the fifth trial was used for analysis. NIRS-derived pH was averaged in 30 sec increments. Between group differences in MIF and exercise time were tested using paired t-tests. A repeated measures ANOVA was used to analyze effects of AT and exercise time on pH. Results: MIF was not different between groups (mean SD; aerobic=415.6 95.4 N vs. sedentary =505.1 107.4 N). Time to fatigue was greater in the AT than in the sedentary group (mean SD: 611 173 sec vs. 377 162 sec, p<0.05). pH was not different between groups at any time point. Average pH decreased (p<0.05) in both groups from rest (pH=7.4) through 90 sec of exercise (pH=6.9), but did not decrease further throughout the remainder of exercise. Conclusion: Although between group differences in pH were not detected, differences during the onset of exercise

  7. CMOS time-resolved, contact, and multispectral fluorescence imaging for DNA molecular diagnostics.

    Science.gov (United States)

    Guo, Nan; Cheung, Kawai; Wong, Hiu Tong; Ho, Derek

    2014-10-31

    Instrumental limitations such as bulkiness and high cost prevent the fluorescence technique from becoming ubiquitous for point-of-care deoxyribonucleic acid (DNA) detection and other in-field molecular diagnostics applications. The complimentary metal-oxide-semiconductor (CMOS) technology, as benefited from process scaling, provides several advanced capabilities such as high integration density, high-resolution signal processing, and low power consumption, enabling sensitive, integrated, and low-cost fluorescence analytical platforms. In this paper, CMOS time-resolved, contact, and multispectral imaging are reviewed. Recently reported CMOS fluorescence analysis microsystem prototypes are surveyed to highlight the present state of the art.

  8. CMOS Time-Resolved, Contact, and Multispectral Fluorescence Imaging for DNA Molecular Diagnostics

    Directory of Open Access Journals (Sweden)

    Nan Guo

    2014-10-01

    Full Text Available Instrumental limitations such as bulkiness and high cost prevent the fluorescence technique from becoming ubiquitous for point-of-care deoxyribonucleic acid (DNA detection and other in-field molecular diagnostics applications. The complimentary metal-oxide-semiconductor (CMOS technology, as benefited from process scaling, provides several advanced capabilities such as high integration density, high-resolution signal processing, and low power consumption, enabling sensitive, integrated, and low-cost fluorescence analytical platforms. In this paper, CMOS time-resolved, contact, and multispectral imaging are reviewed. Recently reported CMOS fluorescence analysis microsystem prototypes are surveyed to highlight the present state of the art.

  9. Cosymplectic and contact structures for time-dependent and dissipative Hamiltonian systems

    Science.gov (United States)

    de León, M.; Sardón, C.

    2017-06-01

    In this paper, we apply the geometric Hamilton-Jacobi theory to obtain solutions of classical hamiltonian systems that are either compatible with a cosymplectic or a contact structure. As it is well known, the first structure plays a central role in the theory of time-dependent hamiltonians, whilst the second is here used to treat classical hamiltonians including dissipation terms. The interest of a geometric Hamilton-Jacobi equation is the primordial observation that if a hamiltonian vector field X H can be projected into a configuration manifold by means of a 1-form dW , then the integral curves of the projected vector field X_HdW can be transformed into integral curves of X H provided that W is a solution of the Hamilton-Jacobi equation. In this way, we use the geometric Hamilton-Jacobi theory to derive solutions of physical systems with a time-dependent hamiltonian formulation or including dissipative terms. Explicit, new expressions for a geometric Hamilton-Jacobi equation are obtained on a cosymplectic and a contact manifold. These equations are later used to solve physical examples containing explicit time dependence, as it is the case of a unidimensional trigonometric system, and two dimensional nonlinear oscillators as Winternitz-Smorodinsky oscillators and for explicit dissipative behavior, we solve the example of a unidimensional damped oscillator.

  10. On the control of bistability in non-contact mode AFM using modulated time delay

    Directory of Open Access Journals (Sweden)

    Kirrou I.

    2014-01-01

    Full Text Available We study the control of bistability in non-contact mode AFM using time delay with modulated feedback gain. We consider that the tip-sample interaction force is described by Lennard-Jones potential and the equation of motion is modeled by single degree of freedom system. Perturbation analysis is performed to obtain the modulation equations of the slow dynamic. The influence of the modulated time delay on the nonlinear characteristic of the frequency response is analyzed and the evolution of the bistability region in the modulated time delay parameter plan is examined. Results show that modulation of the feedback gain can be used to reduce the amplitude of the microcanteliver response and to suppress the bistability regime in large region of the modulated delay parameter space. The analytical predictions are compared to numerical simulations for validation.

  11. Longer Contact Times Increase Cross-Contamination of Enterobacter aerogenes from Surfaces to Food.

    Science.gov (United States)

    Miranda, Robyn C; Schaffner, Donald W

    2016-11-01

    Bacterial cross-contamination from surfaces to food can contribute to foodborne disease. The cross-contamination rate of Enterobacter aerogenes on household surfaces was evaluated by using scenarios that differed by surface type, food type, contact time (<1, 5, 30, and 300 s), and inoculum matrix (tryptic soy broth or peptone buffer). The surfaces used were stainless steel, tile, wood, and carpet. The food types were watermelon, bread, bread with butter, and gummy candy. Surfaces (25 cm(2)) were spot inoculated with 1 ml of inoculum and allowed to dry for 5 h, yielding an approximate concentration of 10(7) CFU/surface. Foods (with a 16-cm(2) contact area) were dropped onto the surfaces from a height of 12.5 cm and left to rest as appropriate. Posttransfer, surfaces and foods were placed in sterile filter bags and homogenized or massaged, diluted, and plated on tryptic soy agar. The transfer rate was quantified as the log percent transfer from the surface to the food. Contact time, food, and surface type all had highly significant effects (P < 0.000001) on the log percent transfer of bacteria. The inoculum matrix (tryptic soy broth or peptone buffer) also had a significant effect on transfer (P = 0.013), and most interaction terms were significant. More bacteria transferred to watermelon (∼0.2 to 97%) than to any other food, while the least bacteria transferred to gummy candy (∼0.1 to 62%). Transfer of bacteria to bread (∼0.02 to 94%) was similar to transfer of bacteria to bread with butter (∼0.02 to 82%), and these transfer rates under a given set of conditions were more variable than with watermelon and gummy candy.

  12. Characterization of Time-Dependent Contact Angles for Oleic Acid Mixed Sands with Different Particle Size Fractions

    DEFF Research Database (Denmark)

    Wijewardana, Y. N. S.; Kawamoto, Ken; Komatsu, Toshiko

    2014-01-01

    ) mixed sands representing four different particle size fractions ranging from 0.105 to 0.84 mm. Initial soil-water contact angle (αi), and the time dependence of contact angle were measured by the sessile drop method. Results showed that the αi value for fine and middle sand fractions increased rapidly...

  13. The effect of inter-particle contact time in granular flows -- A network theory

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D.Z.; Rauenzahn, R.M.

    1996-12-31

    In a kinetic theory, it is usually assumed that the time duration of particle collision is vanishingly small and only binary collisions are considered. The validity of these assumptions depends on the ratio of collision time to mean free flight time. If this ratio is small, the kinetic theory description is appropriate. In a dense system, however, this ratio is usually large, and the dynamics of the multi-particle interactions have to be considered. For instance, during a collision, the contacting pair usually has a relative tangential velocity that causes a change in the direction of rebound. This implies a dependence of the granular stress on the vorticity of the mean flows field. Due to the inherent energy dissipation in a particle collision, and the consistent rearrangement of particles, there are relaxation times associated with them. In a binary collision, this energy dissipation is represented by coefficient of restitution. In a dense granular system, multi-particle interactions occur frequently. The energy dissipation and system relaxation have to be studied by the consideration of the dynamics in the duration of particle interaction and cannot be represented by a single coefficient of restitution. In this case, the relaxation times must be introduced explicitly. By modification of the network theory for rubber material, a constitutive model for dense granular material is developed based on the dynamics of multi-particle interaction. The finite particle interaction time and system relaxation times are considered.

  14. Development of time and pH dependent controlled release colon specific delivery of tinidazole

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available Purpose: Tinidazole is used in treatment of amoebiasis and other protozoal infections in doses of 2.0 g/ day (60 mg/kg for three days. In the present paper, controlled release formulation of tinidazole was developed with an objective to achieve colon specific drug delivery with reduced frequency of dosing, to minimize gastric side effects and thus to increase patient compliance. Methods: Matrix systems of tinidazole (500 mg were prepared by using swellable and pH dependent polymers like hydroxypropyl methylcellulose (HPMC K4M and K15M and eudragit (eudragit L-100 and S-100. Prepared tablets were enteric coated in order to overcome variability in gastric emptying time and delay in the release, to reduce gastric side effects and to provide prolonged localized action in colon. Process of manufacture was optimized during the scale up studies. Bioavailability study (using parallel group design was carried of on conventional marketed, developed uncoated and enteric coated tablets in healthy human volunteers. Results: Bioavailability study showed that greater portion of tinidazole was released in the large intestine and drug level in plasma was above 4 mg/mL in blood for 24 hours. Conclusion: From the results of this study it appears that, the proposed single enteric coated tinidazole (500 mg tablet per day could be used in place of 3-4 doses of 500 mg tinidazole conventional tablet with better control of drug release for targeted drug delivery. In addition developed colon-specific drug delivery system (CDDS was relatively inexpensive and easy to manufacture using conventional pharmaceutical coating technique.

  15. An engineering time-domain model for curve squeal: Tangential point-contact model and Green's functions approach

    Science.gov (United States)

    Zenzerovic, I.; Kropp, W.; Pieringer, A.

    2016-08-01

    Curve squeal is a strong tonal sound that may arise when a railway vehicle negotiates a tight curve. In contrast to frequency-domain models, time-domain models are able to capture the nonlinear and transient nature of curve squeal. However, these models are computationally expensive due to requirements for fine spatial and time discretization. In this paper, a computationally efficient engineering model for curve squeal in the time-domain is proposed. It is based on a steady-state point-contact model for the tangential wheel/rail contact and a Green's functions approach for wheel and rail dynamics. The squeal model also includes a simple model of sound radiation from the railway wheel from the literature. A validation of the tangential point-contact model against Kalker's transient variational contact model reveals that the point-contact model performs well within the squeal model up to at least 5 kHz. The proposed squeal model is applied to investigate the influence of lateral creepage, friction and wheel/rail contact position on squeal occurrence and amplitude. The study indicates a significant influence of the wheel/rail contact position on squeal frequencies and amplitudes. Friction and lateral creepage show an influence on squeal occurrence and amplitudes, but this is only secondary to the influence of the contact position.

  16. Neonatal non-contact respiratory monitoring based on real-time infrared thermography

    Science.gov (United States)

    2011-01-01

    Background Monitoring of vital parameters is an important topic in neonatal daily care. Progress in computational intelligence and medical sensors has facilitated the development of smart bedside monitors that can integrate multiple parameters into a single monitoring system. This paper describes non-contact monitoring of neonatal vital signals based on infrared thermography as a new biomedical engineering application. One signal of clinical interest is the spontaneous respiration rate of the neonate. It will be shown that the respiration rate of neonates can be monitored based on analysis of the anterior naris (nostrils) temperature profile associated with the inspiration and expiration phases successively. Objective The aim of this study is to develop and investigate a new non-contact respiration monitoring modality for neonatal intensive care unit (NICU) using infrared thermography imaging. This development includes subsequent image processing (region of interest (ROI) detection) and optimization. Moreover, it includes further optimization of this non-contact respiration monitoring to be considered as physiological measurement inside NICU wards. Results Continuous wavelet transformation based on Debauches wavelet function was applied to detect the breathing signal within an image stream. Respiration was successfully monitored based on a 0.3°C to 0.5°C temperature difference between the inspiration and expiration phases. Conclusions Although this method has been applied to adults before, this is the first time it was used in a newborn infant population inside the neonatal intensive care unit (NICU). The promising results suggest to include this technology into advanced NICU monitors. PMID:22243660

  17. Neonatal non-contact respiratory monitoring based on real-time infrared thermography

    Directory of Open Access Journals (Sweden)

    Abbas Abbas K

    2011-10-01

    Full Text Available Abstract Background Monitoring of vital parameters is an important topic in neonatal daily care. Progress in computational intelligence and medical sensors has facilitated the development of smart bedside monitors that can integrate multiple parameters into a single monitoring system. This paper describes non-contact monitoring of neonatal vital signals based on infrared thermography as a new biomedical engineering application. One signal of clinical interest is the spontaneous respiration rate of the neonate. It will be shown that the respiration rate of neonates can be monitored based on analysis of the anterior naris (nostrils temperature profile associated with the inspiration and expiration phases successively. Objective The aim of this study is to develop and investigate a new non-contact respiration monitoring modality for neonatal intensive care unit (NICU using infrared thermography imaging. This development includes subsequent image processing (region of interest (ROI detection and optimization. Moreover, it includes further optimization of this non-contact respiration monitoring to be considered as physiological measurement inside NICU wards. Results Continuous wavelet transformation based on Debauches wavelet function was applied to detect the breathing signal within an image stream. Respiration was successfully monitored based on a 0.3°C to 0.5°C temperature difference between the inspiration and expiration phases. Conclusions Although this method has been applied to adults before, this is the first time it was used in a newborn infant population inside the neonatal intensive care unit (NICU. The promising results suggest to include this technology into advanced NICU monitors.

  18. Medium initial pH and carbon source stimulate differential alkaline cellulase time course production in Stachybotrys microspora.

    Science.gov (United States)

    Ben Hmad, Ines; Abdeljalil, Salma; Saibi, Walid; Amouri, Bahia; Gargouri, Ali

    2014-03-01

    The production profile of cellulases of the mutant strain A19 from the filamentous fungus Stachybotrys microspora was studied in the presence of various carbon sources (glucose, lactose, cellulose, carboxymethylcellulose (CMC), and wheat bran) and a range of medium initial pH (5, 7, and 8). Two extracellular cellulases from the Stachybotrys strain (endoglucanases and β-glucosidases) were monitored by enzymatic assay, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and zymogram analysis. Glucose and lactose repressed CMCase time course production while they permitted a strong β-glucosidase one. On Avicel cellulose, CMC, and wheat bran, both activities were highly produced. Wheat bran (WB) is the best carbon source with an optimum of production at days 5 and 6. The production kinetics of both activities were shown to depend on the medium initial pH, with a preference for neutral or alkaline pH in the majority of conditions. The exception concerned the β-glucosidase which was much more produced at acidic pH, on glucose and cellulose. Most interestingly, a constitutive and conditional expression of an alkaline endoglucanase was revealed on the glucose-based medium at an initial pH of 8 units. The zymogram analysis confirmed such conclusions and highlighted that carbon sources and the pH of the culture medium directed a differential induction of various endoglucanases and β-glucosidases.

  19. Observational study to determine predictors of rheumatology clinic visit provider contact time

    Science.gov (United States)

    Davis, Lisa A.; Larson, Molly M.; Caplan, Liron

    2014-01-01

    Objective To address perceived inefficiencies in an academic rheumatology practice, a timing/work-flow evaluation was initiated to determine the factors that predict the Provider Contact Time (PCT)—the amount of time that attending physicians spend with patients during an outpatient encounter. Methods This prospective observational study was conducted at the University of Colorado Hospital rheumatology clinic for return patient visits in early 2008. Each patient encounter was subdivided into components and the time for each component was recorded. Up to 20 return visit encounters per provider were randomly selected for inclusion. Multivariate linear regression was used to predict the time, in minutes, that providers spend with patients and logistic regression was used to determine the time intervals associated with patients' perception that the visit ran on time. Results Variables associated with increased PCT were whether a procedure was performed in the clinic (p=0.037) and whether the visit occurred in the afternoon (p<0.025). For every minute a provider was late in beginning to see a patient, the PCT decreased by 0.32 minutes (C.I. 0.15-0.49). Variables associated with patient's perception that the visit ran on time include the Check In-To-Vital Delay (O.R. 0.95, C.I. 0.92-0.99) and the Provider Delay (O.R. 0.92, 95% CI 0.86-0.99). Conclusion Patients' punctuality and the presence of a resident were not significantly associated with the time that a provider spent with a patient. However, the degree to which the provider ran late was associated with decreased PCT and diminished the patient's perception that the visit ran on time. PMID:20583104

  20. The Varying Light Curve and Timings of the Ultra-short Period Contact Binary KIC 9532219

    CERN Document Server

    Lee, Jae Woo; Koo, Jae-Rim; Park, Jang-Ho

    2016-01-01

    KIC 9532219 is a W UMa-type eclipsing binary with an orbital period of 0.1981549 d that is below the short-period limit ($\\sim$0.22 d) of the period distribution for contact binaries. The {\\it Kepler} light curve of the system exhibits striking light changes in both eclipse depths and light maxima. Applying third-body and spot effects, the light-curve synthesis indicates that the eclipsing pair is currently in a marginal contact stage with a mass ratio of $q$=1.20, an orbital inclination of $i$=66.0 deg, a temperature difference of $\\Delta$ ($T_{1}$--$T_{2}$)=172 K, and a third light of $l_3$=75.9 \\%. To understand the light variations with time, we divided up the light curve into 312 segments and separately analyzed them. The results reveal that variation of eclipse depth is primarily caused by changing amounts of contamination due to the nearby star KIC9532228 between the {\\it Kepler} Quarters and that the variable O'Connell effect originates from the starspot activity on the less massive primary component....

  1. THE VARYING LIGHT CURVE AND TIMINGS OF THE ULTRASHORT-PERIOD CONTACT BINARY KIC 9532219

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Woo; Hong, Kyeongsoo; Koo, Jae-Rim; Park, Jang-Ho, E-mail: jwlee@kasi.re.kr, E-mail: kshong@kasi.re.kr, E-mail: koojr@kasi.re.kr, E-mail: pooh107162@kasi.re.kr [Korea Astronomy and Space Science Institute, Daejeon 34055 (Korea, Republic of)

    2016-03-20

    KIC 9532219 is a W UMa-type eclipsing binary with an orbital period of 0.1981549 days that is below the short-period limit (∼0.22 days) of the period distribution for contact binaries. The Kepler light curve of the system exhibits striking changes in both eclipse depths and light maxima. Applying third-body and spot effects, the light-curve synthesis indicates that the eclipsing pair is currently in a marginal contact stage with a mass ratio of q = 1.20, an orbital inclination of i = 66.°0, a temperature difference of T{sub 1}–T{sub 2} = 172 K, and a third light of l{sub 3} = 75.9%. To understand the light variations with time, we divided up the light curve into 312 segments and analyzed them separately. The results reveal that variation of eclipse depth is primarily caused by changing amounts of contamination due to the nearby star KIC 9532228 between the Kepler Quarters and that the variable O’Connell effect originates from the starspot activity on the less massive primary component. Based on our light-curve timings, a period study of KIC 9532219 indicates that the orbital period has varied as a combination of a downward parabola and a light-travel-time (LTT) effect due to a third body, which has a period of 1196 days and a minimum mass of 0.0892 M{sub ⊙} in an orbit of eccentricity 0.150. The parabolic variation could be a small part of a second LTT orbit due to a fourth component in a wider orbit, instead of either mass transfer or angular momentum loss.

  2. Real time optimization of solar powered direct contact membrane distillation based on multivariable extremum seeking

    KAUST Repository

    Karam, Ayman M.

    2015-09-21

    This paper presents a real time optimization scheme for a solar powered direct contact membrane distillation (DCMD) water desalination system. The sun and weather conditions vary and are inconsistent throughout the day. Therefore, the solar powered DCMD feed inlet temperature is never constant, which influences the distilled water flux. The problem of DCMD process optimization has not been studied enough. In this work, the response of the process under various feed inlet temperatures is investigated, which demonstrates the need for an optimal controller. To address this issue, we propose a multivariable Newton-based extremum seeking controller which optimizes the inlet feed and permeate mass flow rates as the feed inlet temperature varies. Results are presented and discussed for a realistic temperature profile.

  3. The leaching of major and trace elements from MSWI bottom ash as a function of pH and time

    NARCIS (Netherlands)

    Dijkstra, J.J.; Sloot, van der H.A.; Comans, R.N.J.

    2006-01-01

    In this paper, the leaching behaviour of major components (Al, Ca, SO4, Mg, Si, Fe, Na and DOC) and trace elements (Ni, Zn, Cd, Cu, Pb, Mo and Sb) from MSWI bottom ash is studied as a function of time over a wide range of pH, under pH-controlled conditions. Equilibrium geochemical modelling using th

  4. The Marginal Distributions of a Crossing Time and Renewal Numbers Related with Two Poisson Processes are as Ph-Distributions

    Directory of Open Access Journals (Sweden)

    Mir G. H. Talpur

    2006-01-01

    Full Text Available In this paper we consider, how to find the marginal distributions of crossing time and renewal numbers related with two poisson processes by using probability arguments. The obtained results show that the one-dimension marginal distributions are N+1 order PH-distributions.

  5. The Near-contact Binary RZ Draconis with Two Possible Light-time Orbits

    Science.gov (United States)

    Yang, Y.-G.; Li, H.-L.; Dai, H.-F.; Zhang, L.-Y.

    2010-12-01

    We present new multicolor photometry for RZ Draconis, observed in 2009 at the Xinglong Station of the National Astronomical Observatories of China. By using the updated version of the Wilson-Devinney Code, the photometric-spectroscopic elements were deduced from new photometric observations and published radial velocity data. The mass ratio and orbital inclination are q = 0.375(±0.002) and i = 84fdg60(±0fdg13), respectively. The fill-out factor of the primary is f = 98.3%, implying that RZ Dra is an Algol-like near-contact binary. Based on 683 light minimum times from 1907 to 2009, the orbital period change was investigated in detail. From the O - C curve, it is discovered that two quasi-sinusoidal variations may exist (i.e., P 3 = 75.62(±2.20) yr and P 4 = 27.59(±0.10) yr), which likely result from light-time effects via the presence of two additional bodies. In a coplanar orbit with the binary system, the third and fourth bodies may be low-mass drafts (i.e., M 3 = 0.175 M sun and M 4 = 0.074 M sun). If this is true, RZ Dra may be a quadruple star. The additional body could extract angular momentum from the binary system, which may cause the orbit to shrink. With the orbit shrinking, the primary may fill its Roche lobe and RZ Dra evolves into a contact configuration.

  6. The time course of the transcriptomic response of Sinorhizobium meliloti 1021 following a shift to acidic pH

    Directory of Open Access Journals (Sweden)

    Pühler Alfred

    2009-02-01

    Full Text Available Abstract Background The symbiotic soil bacterium Sinorhizobium meliloti often has to face low pH in its natural habitats. To identify genes responding to pH stress a global transcriptional analysis of S. meliloti strain 1021 following a pH shift from pH 7.0 to pH 5.75 was carried out. In detail, oligo-based whole genome microarrays were used in a time course experiment. The monitoring period covered a time span of about one hour after the pH shift. The obtained microarray data was filtered and grouped by K-means clustering in order to obtain groups of genes behaving similarly concerning their expression levels throughout the time course. Results The results display a versatile response of S. meliloti 1021 represented by distinct expression profiles of subsets of genes with functional relation. The eight generated clusters could be subdivided into a group of four clusters containing genes that were up-regulated and another group of four clusters containing genes that were down-regulated in response to the acidic pH shift. The respective mean expression progression of the four up-regulated clusters could be described as (i permanently and strong, (ii permanently and intermediate, (iii permanently and progressive, and (iv transiently up-regulated. The expression profile of the four down-regulated clusters could be characterized as (i permanently, (ii permanently and progressive, (iii transiently, and (iv ultra short down-regulated. Genes coding for proteins with functional relation were mostly cumulated in the same cluster, pointing to a characteristic expression profile for distinct cellular functions. Among the strongest up-regulated genes lpiA, degP1, cah, exoV and exoH were found. The most striking functional groups responding to the shift to acidic pH were genes of the exopolysaccharide I biosynthesis as well as flagellar and chemotaxis genes. While the genes of the exopolysaccharide I biosynthesis (exoY, exoQ, exoW, exoV, exoT, exoH, exoK exo

  7. Prioritized Contact Transport Stream

    Science.gov (United States)

    Hunt, Walter Lee, Jr. (Inventor)

    2015-01-01

    A detection process, contact recognition process, classification process, and identification process are applied to raw sensor data to produce an identified contact record set containing one or more identified contact records. A prioritization process is applied to the identified contact record set to assign a contact priority to each contact record in the identified contact record set. Data are removed from the contact records in the identified contact record set based on the contact priorities assigned to those contact records. A first contact stream is produced from the resulting contact records. The first contact stream is streamed in a contact transport stream. The contact transport stream may include and stream additional contact streams. The contact transport stream may be varied dynamically over time based on parameters such as available bandwidth, contact priority, presence/absence of contacts, system state, and configuration parameters.

  8. Adaptive method for real-time gait phase detection based on ground contact forces.

    Science.gov (United States)

    Yu, Lie; Zheng, Jianbin; Wang, Yang; Song, Zhengge; Zhan, Enqi

    2015-01-01

    A novel method is presented to detect real-time gait phases based on ground contact forces (GCFs) measured by force sensitive resistors (FSRs). The traditional threshold method (TM) sets a threshold to divide the GCFs into on-ground and off-ground statuses. However, TM is neither an adaptive nor real-time method. The threshold setting is based on body weight or the maximum and minimum GCFs in the gait cycles, resulting in different thresholds needed for different walking conditions. Additionally, the maximum and minimum GCFs are only obtainable after data processing. Therefore, this paper proposes a proportion method (PM) that calculates the sums and proportions of GCFs wherein the GCFs are obtained from FSRs. A gait analysis is then implemented by the proposed gait phase detection algorithm (GPDA). Finally, the PM reliability is determined by comparing the detection results between PM and TM. Experimental results demonstrate that the proposed PM is highly reliable in all walking conditions. In addition, PM could be utilized to analyze gait phases in real time. Finally, PM exhibits strong adaptability to different walking conditions.

  9. Development of a ratiometric time-resolved luminescence sensor for pH based on lanthanide complexes

    Energy Technology Data Exchange (ETDEWEB)

    Liu Mingjing [State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024 (China); Ye Zhiqiang, E-mail: zhiqiangye2001@yahoo.com.cn [State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024 (China); Xin Chenglong [State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024 (China); Yuan Jingli, E-mail: jingliyuan@yahoo.com.cn [State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024 (China)

    2013-01-25

    Highlights: Black-Right-Pointing-Pointer A lanthanide complex-based ratiometric luminescent pH sensor was developed. Black-Right-Pointing-Pointer The sensor can luminously respond to pH in weakly acidic to neutral media. Black-Right-Pointing-Pointer The sensor can be used for monitoring pH with time-resolved luminescence mode. Black-Right-Pointing-Pointer The sensor can be also used for monitoring pH with absorbance mode. Black-Right-Pointing-Pointer The utility of the sensor for the luminescent cell imaging was demonstrated. - Abstract: Time-resolved luminescence bioassay technique using lanthanide complexes as luminescent probes/sensors has shown great utilities in clinical diagnostics and biotechnology discoveries. In this work, a novel terpyridine polyacid derivative that can form highly stable complexes with lanthanide ions in aqueous media, (4 Prime -hydroxy-2,2 Prime :6 Prime ,2 Prime Prime -terpyridine-6,6 Prime Prime -diyl) bis(methylenenitrilo) tetrakis(acetic acid) (HTTA), was designed and synthesized for developing time-resolved luminescence pH sensors based on its Eu{sup 3+} and Tb{sup 3+} complexes. The luminescence characterization results reveal that the luminescence intensity of HTTA-Eu{sup 3+} is strongly dependent on the pH values in weakly acidic to neutral media (pK{sub a} = 5.8, pH 4.8-7.5), while that of HTTA-Tb{sup 3+} is pH-independent. This unique luminescence response allows the mixture of HTTA-Eu{sup 3+} and HTTA-Tb{sup 3+} (the HTTA-Eu{sup 3+}/Tb{sup 3+} mixture) to be used as a ratiometric luminescence sensor for the time-resolved luminescence detection of pH with the intensity ratio of its Tb{sup 3+} emission at 540 nm to its Eu{sup 3+} emission at 610 nm, I{sub 540nm}/I{sub 610nm}, as a signal. Moreover, the UV absorption spectrum changes of the HTTA-Eu{sup 3+}/Tb{sup 3+} mixture at different pHs (pH 4.0-7.0) also display a ratiometric response to the pH changes with the ratio of absorbance at 290 nm to that at 325 nm, A{sub 290nm

  10. Time-to-Fatigue and Intramuscular pH measured via NIRS during Handgrip Exercise in Trained and Sedentary Individuals

    Science.gov (United States)

    Everett, M. E.; Lee, S. M. C.; Stroud, L.; Scott, P.; Hagan, R. D.; Soller, B.R.

    2009-01-01

    In exercising muscles force production and muscular endurance are impaired by a decrease in intramuscular pH. The effects of aerobic training (AT) on preventing acidosis and prolonging exercise time in muscles not specifically targeted by the training are unknown. Purpose: To compare interstitial pH, measured non-invasively with near infrared spectroscopy (NIRS), in the flexor digitorum profundus (FDP) during rhythmic handgrip exercise in sedentary subjects and those who participate in AT activities that target the lower body. Methods: Maximal isometric force (MIF) was measured on three separate days in AT (n=5) and sedentary (n=8) subjects using a handgrip dynamometer (HGD). Isometric muscular endurance (IME) was measured during five trials, each separated by at least 48 hrs. For each IME trial subjects rhythmically squeezed (4 sec at 40% of MVC) and relaxed (2 sec) to fatigue or failure to reach the target force in three consecutive contractions or four non-consecutive contractions. Interstitial pH was derived from spectra collected using a NIRS sensor adhered to the skin over the FDP. The first four IME trials served to familiarize subjects with the protocol; the fifth trial was used for analysis. NIRS-derived pH was averaged in 30 sec increments. Between group differences in MIF and exercise time were tested using paired t-tests. A repeated measures ANOVA was used to analyze effects of AT and exercise time on pH. Results: MIF was not different between groups (mean SD; aerobic=415.6 95.4 N vs. sedentary =505.1 107.4 N). Time to fatigue was greater in the AT than in the sedentary group (mean SD: 611 173 sec vs. 377 162 sec, pmuscular work, possibly due to psychological familiarization to muscular fatigue and/or systemic physiological benefits.

  11. Biofeedback for Gait Retraining Based on Real-Time Estimation of Tibiofemoral Joint Contact Forces.

    Science.gov (United States)

    Pizzolato, Claudio; Reggiani, Monica; Saxby, David J; Ceseracciu, Elena; Modenese, Luca; Lloyd, David G

    2017-09-01

    Biofeedback assisted rehabilitation and intervention technologies have the potential to modify clinically relevant biomechanics. Gait retraining has been used to reduce the knee adduction moment, a surrogate of medial tibiofemoral joint loading often used in knee osteoarthritis research. In this paper, we present an electromyogram-driven neuromusculoskeletal model of the lower-limb to estimate, in real-time, the tibiofemoral joint loads. The model included 34 musculotendon units spanning the hip, knee, and ankle joints. Full-body inverse kinematics, inverse dynamics, and musculotendon kinematics were solved in real-time from motion capture and force plate data to estimate the knee medial tibiofemoral contact force (MTFF). We analyzed five healthy subjects while they were walking on an instrumented treadmill with visual biofeedback of their MTFF. Each subject was asked to modify their gait in order to vary the magnitude of their MTFF. All subjects were able to increase their MTFF, whereas only three subjects could decrease it, and only after receiving verbal suggestions about possible gait modification strategies. Results indicate the important role of knee muscle activation patterns in modulating the MTFF. While this paper focused on the knee, the technology can be extended to examine the musculoskeletal tissue loads at different sites of the human body.

  12. Terahertz time domain interferometry of a SIS tunnel junction and a quantum point contact

    Energy Technology Data Exchange (ETDEWEB)

    Karadi, Chandu [Univ. of California, Berkeley, CA (United States). Dept. of Physics

    1995-09-01

    The author has applied the Terahertz Time Domain Interferometric (THz-TDI) technique to probe the ultrafast dynamic response of a Superconducting-Insulating-Superconducting (SIS) tunnel junction and a Quantum Point Contact (QPC). The THz-TDI technique involves monitoring changes in the dc current induced by interfering two picosecond electrical pulses on the junction as a function of time delay between them. Measurements of the response of the Nb/AlOxNb SIS tunnel junction from 75--200 GHz are in full agreement with the linear theory for photon-assisted tunneling. Likewise, measurements of the induced current in a QPC as a function of source-drain voltage, gate voltage, frequency, and magnetic field also show strong evidence for photon-assisted transport. These experiments together demonstrate the general applicability of the THz-TDI technique to the characterization of the dynamic response of any micron or nanometer scale device that exhibits a non-linear I-V characteristic.

  13. Nonlinear time-series analysis of current signal in cathodic contact glow discharge electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Allagui, Anis, E-mail: aallagui@sharjah.ac.ae; Abdelkareem, Mohammad Ali [Department of Sustainable and Renewable Energy Engineering, University of Sharjah, PO Box 27272, Sharjah (United Arab Emirates); Rojas, Andrea Espinel [Institut de Recherche en Communications et Cybernétique de Nantes, Ecole Centrale de Nantes, 44300 Nantes (France); Bonny, Talal; Elwakil, Ahmed S. [Department of Electrical and Computer Engineering, University of Sharjah, PO Box 27272, Sharjah (United Arab Emirates)

    2016-05-28

    In the standard two-electrode configuration employed in electrolytic process, when the control dc voltage is brought to a critical value, the system undergoes a transition from conventional electrolysis to contact glow discharge electrolysis (CGDE), which has also been referred to as liquid-submerged micro-plasma, glow discharge plasma electrolysis, electrode effect, electrolytic plasma, etc. The light-emitting process is associated with the development of an irregular and erratic current time-series which has been arbitrarily labelled as “random,” and thus dissuaded further research in this direction. Here, we examine the current time-series signals measured in cathodic CGDE configuration in a concentrated KOH solution at different dc bias voltages greater than the critical voltage. We show that the signals are, in fact, not random according to the NIST SP. 800-22 test suite definition. We also demonstrate that post-processing low-pass filtered sequences requires less time than the native as-measured sequences, suggesting a superposition of low frequency chaotic fluctuations and high frequency behaviors (which may be produced by more than one possible source of entropy). Using an array of nonlinear time-series analyses for dynamical systems, i.e., the computation of largest Lyapunov exponents and correlation dimensions, and re-construction of phase portraits, we found that low-pass filtered datasets undergo a transition from quasi-periodic to chaotic to quasi-hyper-chaotic behavior, and back again to chaos when the voltage controlling-parameter is increased. The high frequency part of the signals is discussed in terms of highly nonlinear turbulent motion developed around the working electrode.

  14. Demineralization of root canal dentine with EDTA and citric acid in different concentrations, pH and application times

    Directory of Open Access Journals (Sweden)

    Mr.Sc. Nexhmije Ajeti

    2011-12-01

    Full Text Available Abstract The aims of the study are: 1. Determination of the amount of extracted Ca ions from den-tine using 17% and 10% EDTA, at pH 7 and pH 9. 2. Determination of the amount of extracted Ca ions from  den-tine using citric acid 5% and 1%, at pH 7 and pH 9.  Methodology 30 extracted, single rooted, human teeth were tested. Their crowns were sectioned at CEJ using diamond disks. The root canals were manually prepared with K-files #50-60. After each instrument 2.5 ml of 5.25% NaOCl was used and 0.9 NaCl as final irrigation. All teeth were longitudinally sectioned and 8 samples of dentine taken from each sample. EDTA 10% and 17 % and citric acid 1% and 5% in neutral and alkaline pH were used.  Each sample was immersed in acid and then exposure time was evaluated after 1, 5, 10, 15 and 25 min. The release rate of calcium ions from root dentine was evaluated by atomic absorption spectrometer.  Results There were significant differences in the amount of extracted Ca by citric acid 1% and 5% or EDTA 10% and 17% in human teeth.  Conclusions It may be concluded that EDTA is a better chelating agent than citric acid. The decalcifying activity of these solutions is related to the duration of exposure, pH and their concentrations.

  15. RTEMIS: Real-time Tumoroid and Environment Monitoring Using Impedance Spectroscopy and pH Sensing

    Science.gov (United States)

    Alexander, Frank A., Jr.

    This research utilizes Electrical Impedance Spectroscopy, a technique classically used for electrochemical analysis and material characterization, as the basis for a non-destructive, label-free assay platform for three dimensional (3D) cellular spheroids. In this work, a linear array of microelectrodes is optimized to rapidly respond to changes located within a 3D multicellular model. In addition, this technique is coupled with an on chip micro-pH sensor for monitoring the environment around the cells. Finally, the responses of both impedance and pH are correlated with physical changes within the cellular model. The impedance analysis system realized through this work provides a foundation for the development of high-throughput drug screening systems that utilize multiple parallel sensing modalities including pH and impedance sensing in order to quickly assess the efficacy of specific drug candidates. The slow development of new drugs is mainly attributed to poor predictability of current chemosensitivity and resistivity assays, as well as genetic differences between the animal models used for tests and humans. In addition, monolayer cultures used in early experimentation are fundamentally different from the complex structure of organs in vivo. This requires the study of smaller 3D models (spheroids) that more efficiently replicate the conditions within the body. The main objective of this research was to develop a microfluidic system on a chip that is capable of deducing viability and morphology of 3D tumor spheroids by monitoring both the impedance of the cellular model and the pH of their local environment. This would provide a fast and reliable method for screening pharmaceutical compounds in a high-throughput system.

  16. Characterization of PEBBLEs as a Tool for Real-Time Measurement of Dictyostelium discoideum Endosomal pH

    Directory of Open Access Journals (Sweden)

    Everett Moding

    2009-01-01

    Full Text Available The measurement of intracellular ion concentration change is important for understanding the cellular mechanisms for communication. Recently developed nanosensors, (Photonic Explorers for Biomedical use with Biologically Localized Embedding PEBBLEs, have a number of advantages for measuring ions in cells over established methods using microelectrodes, unbound fluorescent dyes, or NMR. PEBBLE sensors have been shown to work in principle for measuring dynamic ion changes, but few in vivo applications have been demonstrated. We modified the protocol for the fabrication of pH sensing PEBBLEs and developed a protocol for the utilization of these sensors for the monitoring of dynamic pH changes in the endosomes of slime mold Dictyostelium discoideum (D. discoideum. Oregon Green 514-CdSe Quantum Dot PEBBLEs were used to measure real-time pH inside D. discoideum endosomes during cAMP stimulation. Endosomal pH was shown to decrease during cAMP signaling, demonstrating a movement of protons into the endosomes of D. discoideum amoebae.

  17. Assessment of bacterial biodetoxification of herbicide atrazine using Aliivibrio fischeri cytotoxicity assay with prolonged contact time.

    Science.gov (United States)

    Háhn, Judit; Szoboszlay, Sándor; Tóth, Gergő; Kriszt, Balázs

    2017-07-01

    In our study, we determined and compared the atrazine-biodetoxification ability of 41 bacterial strains and 21 consortia created of those with over 50% degradation rate in pure cultures. Biodegradation capacity was measured with GC-MS. Detoxification was assessed based on the cytotoxic effect of end-products to Aliivibrio fischeri in chronic bioluminescence inhibition assay with 25 h contact time. Chronic A. fischeri assay adapted to a microplate, which is suitable for examine numerous residues simultaneously, also appeared to be significantly more sensitive to atrazine compared to the standard acute (30 min) test. Due to its sensitivity, the chronic assay could be a valuable tool to provide a more comprehensive view of the ecological risks of atrazine and other chemicals. Thirteen strains were able to degrade more than 50% of 50 ppm atrazine. Four of these belong to Rhodococcus aetherivorans, R. qingshengii, Serratia fonticola and Olivibacter oleidegradans which species' atrazine degrading ability has never been reported before. Four consortia degrading ability was more effective than that of the creating individual strains; moreover, their residues did not show cytotoxic effects to A. fischeri. However, in several cases, the degradation products of sole strains and consortia resulted in significant bioluminescence inhibition. Thus high biodegradation (>90%) does not certainly mean the reduction or cessation of toxicity highlighting the importance of the evaluation of biological effects of degradation residues to improve the efficiency and abate the ecological risks of bioremediation techniques.

  18. Between-day reliability of time-to-contact measures used to assess postural stability.

    Science.gov (United States)

    Wheat, Jonathan S; Haddad, Jeffrey M; Scaife, Robert

    2012-02-01

    Traditional measures of postural stability consider movement of the center of pressure (COP) or the center of mass (COM) without regard to the boundary of support (BOS). A potentially more appropriate measure is postural time-to-contact (TtC) which defines the spatio-temporal proximity of the COM or COP to the BOS. Given the increasing popularity of TtC measures, it is important to determine their reliability. Therefore, the purpose of this study was to determine the effects of the number of trials and trial duration on the reliability of postural TtC measures. COP data were collected (100 Hz) in 16 young healthy participants during 10 trials (60-s duration) of quiet standing with eyes open on two occasions - seven days apart. Postural TtC of each trial was calculated using two different methods. The intersession reliability of the TtC measures was assessed by calculating between session intraclass correlation coefficients (ICC(2,1)) using different combinations of the number of trials (1-10) and trial duration (10, 20, 30, 40, 50 and 60s). Both TtC methods were very reliable. Additionally, both measures of TtC were more reliable than the standard deviation of the anterior-posterior COP and slightly more reliable than path length. This difference was most pronounced when fewer and shorter trials were used.

  19. Application of time-dependent sessile drop contact angles on compacts to characterise the surface energetics of sulfathiazole crystals.

    Science.gov (United States)

    Muster, Tim H; Prestidge, Clive A

    2002-03-02

    The time-dependent wetting of sulfathiazole compacts with sessile water drops was evaluated using video microscopy. The influence of sulfathiazole crystalline form, particle size, pre-saturation with water, humidity and compaction pressure on the droplet spreading kinetics and contact angles are reported. The rate and extent of droplet spreading decreased for compact surfaces of high microscopic roughness; this was determined by atomic force microscopy (AFM). Pre-saturation of powder compacts with water (pre-saturated with sulfathiazole) enhanced droplet spreading and enabled pseudo-equilibrium contact angles to be determined for up to 10 min. Sessile-drop contact angles on both sulfathiazole powder compacts and single crystals are compared with particle contact angles determined by liquid penetration. This study has led to an improved understanding of the influence of physical heterogeneities and the face-specific surface chemistry of individual crystals on the wetting characteristics of pharmaceutical compacts.

  20. Predictors of full-time faculty appointment among MD–PhD program graduates: a national cohort study

    Directory of Open Access Journals (Sweden)

    Dorothy A. Andriole

    2016-05-01

    Full Text Available Purpose: The authors sought to identify variables associated with MD–PhD program graduates’ academic medicine careers. Methods: We analyzed data for a national cohort of MD–PhD program graduates from 2000 to 2005, using multivariable logistic regression to identify independent predictors of full-time academic medicine faculty appointment through 2013. Results: Of 1,860 MD–PhD program graduates in 2000–2005, we included 1,846 (99.2% who had completed residency training before 2014. Of these 1,846 graduates, 968 (52.4% held full-time faculty appointments. Graduates who attended schools with Medical Scientist Training Program (MSTP funding (vs. no MSTP funding; adjusted odds ratio [aOR], 1.41; 95% confidence interval [CI], 1.14–1.74 and participated in ≥1 year of research during residency (vs. no documented research year; aOR, 1.85; 95% CI, 1.50–2.28 were more likely to have held full-time faculty appointments. Asian/Pacific Islander (aOR, 0.74; 95% CI, 0.60–0.93 and under-represented minority (URM; aOR, 0.68; 95% CI, 0.48–0.98 graduates (each vs. white graduates, graduates who reported total debt of ≥$100,000 (vs. no debt at graduation (aOR, 0.58; 95% CI, 0.39–0.88, and graduates in surgical practice (aOR, 0.64; 95% CI, 0.48–0.84 and other practice (aOR, 0.66, 95% CI, 0.54–0.81 specialties (each vs. ‘medicine, pediatrics, pathology, or neurology’ were less likely to have held full-time faculty appointments. Gender was not independently associated with likelihood of full-time faculty appointment. Conclusions: Over half of all MD–PhD program graduates in our study had full-time faculty appointments. Our findings regarding variables independently associated with full-time faculty appointments can inform the design of strategies to promote academic medicine career choice among MD–PhD program graduates. Further research is warranted to identify other factors amenable to intervention, in addition to those included in

  1. Time esophageal pH < 4 overestimates the prevalence of pathologic esophageal reflux in subjects with gastroesophageal reflux disease treated with proton pump inhibitors

    Directory of Open Access Journals (Sweden)

    Sloan Sheldon

    2008-05-01

    Full Text Available Abstract Background A Stanford University study reported that in asymptomatic GERD patients who were being treated with a proton pump inhibitor (PPI, 50% had pathologic esophageal acid exposure. Aim We considered the possibility that the high prevalence of pathologic esophageal reflux might simply have resulted from calculating acidity as time pH Methods We calculated integrated acidity and time pH Results The prevalence of pathologic 24-hour esophageal reflux in both studies was significantly higher when measured as time pH Conclusion In GERD subjects treated with a PPI, measuring time esophageal pH

  2. Time-dep endent Calculations for Two-proton Decay Width with Schematic Density-dependent Contact Pairing Interaction

    Institute of Scientific and Technical Information of China (English)

    Oishi Tomohiro

    2016-01-01

    We calculate the two-proton decay width of the 6 Be nucleus employing the schematic density-dependent contact potential for the proton-proton pairing interaction. The decay width is calculated with a time-dependent method, in which the two-proton emission is described as a time-evolution of a three-body meta-stable state. Model-dependence of the two-proton decay width has been shown by comparing the results obtained with the two different pairing models, schematic density-dependent contact and Minnesota interactions, which have zero and finite ranges, respectively.

  3. Investigation of Eu(III) immobilization on γ-Al2O3 surfaces by combining batch technique and EXAFS analyses: Role of contact time and humic acid

    Science.gov (United States)

    Yang, Shitong; Sheng, Guodong; Montavon, Gilles; Guo, Zhiqiang; Tan, Xiaoli; Grambow, Bernd; Wang, Xiangke

    2013-11-01

    Aluminum (hydr)oxides play an important role in the regulation of the composition of soil/water, sediment/water and other natural water systems. In this study, the interactions among Eu(III), humic acid (HA) and γ-Al2O3 were investigated using a combination of batch and extended X-ray absorption fine structure (EXAFS) techniques. Experiments were performed with varying contact times (2, 15, 60 and 180 d) at a pH of 6.5 for both the binary γ-Al2O3/Eu(III) and the ternary γ-Al2O3/HA/Eu(III) systems. In addition, two representative pH values (pH 6.5 for a near-neutral condition and pH 8.5 for an alkalescence condition) were selected to determine the sequestration mechanisms of Eu(III) in the ternary γ-Al2O3/HA/Eu(III) systems. To verify the specific binding modes and corresponding chemical species, a coordination geometry calculation and a quantitative comparison between the HA binding site concentration and the initial Eu(III) concentration were conducted along with EXAFS data analysis. The microstructure and thermodynamic stability of the formed Eu(III) species were dependent on various environmental parameters. For the binary γ-Al2O3/Eu(III) systems, quantitative analysis results of EXAFS spectra suggested the presence of two Eu(III) species within a contact time of 15 d. Using a coordination geometry calculation, the REu-Al values at ∼3.28 Å and ∼3.99 Å corresponded to the formation of edge-shared and corner-shared surface complexes, respectively. For samples reacted longer than 15 d, the appearance of an additional Eu-Eu shell at ∼3.50 Å was indicative of a structural rearrangement process, leading to the formation of thermodynamically stable surface polynuclear complexes. For the ternary γ-Al2O3/HA/Eu(III) systems, the EXAFS-derived structural parameters indicated the formation of 1:1 type B ternary complexes and binary corner-shared complexes at pH 6.5 after 2 d. In contrast, the Eu(III) sequestration mechanisms at pH 8.5 were mainly attributed

  4. Influences of pH and hydraulic retention time on anaerobes converting beer processing wastes into hydrogen.

    Science.gov (United States)

    Lay, J J; Tsai, C J; Huang, C C; Chang, J J; Chou, C H; Fan, K S; Chang, J I; Hsu, P C

    2005-01-01

    To convert high-solids organic wastes (3% w./w.) to high-value hydrogen, a full factorial experimental design was employed in planning the experiments for learning the effects of pH and hydraulic retention time (HRT) on the hydrogen production in a chemostat reactor using waste yeast obtained from beer processing wastes. For determining which experimental variable settings affect hydrogen production, predictive polynomial quadratic equation and response surface methodology were employed to determine and explain the conditions required for high-value hydrogen production. Experimental results indicate that a maximum hydrogen production rate of 460 mL/gVSS/d was obtained at pH = 5.8 and HRT = 32 hours. Moreover, hydrogenase targeted RT-PCR results indicate that Clostridium thermocellum and Klebsiella pneumoniae predominated.

  5. Leaching of boron, arsenic and selenium from sedimentary rocks: I. Effects of contact time, mixing speed and liquid-to-solid ratio.

    Science.gov (United States)

    Tabelin, Carlito Baltazar; Hashimoto, Ayaka; Igarashi, Toshifumi; Yoneda, Tetsuro

    2014-02-15

    Sedimentary rocks of marine origin excavated in tunnel projects were recently identified as potentially hazardous because they could release significant amounts of toxic trace elements when exposed to the environment. This study investigated the leaching characteristics of B, As, Se and the major coexisting ions under various conditions to identify the factors and processes controlling their evolution in the leachate. In addition, we evaluated whether the parameters of the currently used leachability test for excavated rocks were adequate. Although the leachabilities of B, As and Se similarly increased at longer contact times, only those of B and As were influenced by the mixing speed and/or liquid-to-solid ratio (L/S). The majority of trace elements dissolved in the leachate originated from the dissolution of soluble salts formed from seawater of the Cretaceous trapped during the formation of the sedimentary rocks. Moreover, the alkaline pH of the leachates could be attributed to the simultaneous dissolutions at varying degrees of the mineral components of the rocks as well as the precipitation of clay minerals. In the leaching test of excavated rocks for regulatory purposes, the best values of contact time and mixing speed should represent conditions of the highest trace element extractabilities, which in this study were found at longer contact times (>48 h) and the fastest mixing speed (200 rpm). The most appropriate L/S for the leaching test is 10 because it was around this L/S that the extractabilities and leaching concentrations of the trace elements were simultaneously observed at their highest values. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Influence of different sanitizers on food contaminant bacteria: effect of exposure temperature, contact time, and product concentration

    Directory of Open Access Journals (Sweden)

    Cezar Augusto Beltrame

    2012-06-01

    Full Text Available The efficiency of four Sanitizers - peracetic acid, chlorhexidine, quaternary ammonium, and organic acids - was tested in this work using different bacteria recognized as a problem to meat industry, Salmonella sp., S. aureus, E. coli and L. monocytogenes. The effects of sanitizer concentration (0.2, 0.5, 0.6, 1.0, 1.1 and 1.4%, at different temperatures (10 and 45 °C and contact time (2, 10, 15, 18 and 25 minutes were evaluated. Tests in an industrial plant were also carried out considering previously obtained results. In a general way, peracetic acid presented higher efficiencies using low concentration (0.2% and contact time (2 minutes at 10 °C. The tests performed in industrial scale showed that peracetic acid presented a good performance in concentration and contact time lower than that suggested by the suppliers. The use of chlorhexidine and quaternary ammonium led to reasonable results at the indicated conditions, and organic acids were ineffective under concentration and contact time higher than those indicated by the suppliers in relation to Staphylococcus aureus. The results, in general, show that the choice for the most adequate sanitizer depends on the microorganism contaminant, the time available for sanitizer application, and also on the process cost.

  7. Logarithmic contact time dependence of adhesion force and its dominant role among the effects of AFM experimental parameters under low humidity

    Science.gov (United States)

    Lai, Tianmao; Meng, Yonggang

    2017-10-01

    The influences of contact time, normal load, piezo velocity, and measurement number of times on the adhesion force between two silicon surfaces were studied with an atomic force microscope (AFM) at low humidity (17-15%). Results show that the adhesion force is time-dependent and increases logarithmically with contact time until saturation is reached, which is related with the growing size of a water bridge between them. The contact time plays a dominant role among these parameters. The adhesion forces with different normal loads and piezo velocities can be quantitatively obtained just by figuring out the length of contact time, provided that the contact time dependence is known. The time-dependent adhesion force with repeated contacts at one location usually increases first sharply and then slowly with measurement number of times until saturation is reached, which is in accordance with the contact time dependence. The behavior of the adhesion force with repeated contacts can be adjusted by the lengths of contact time and non-contact time. These results may help facilitate the anti-adhesion design of silicon-based microscale systems working under low humidity.

  8. Comparison of chlorination and chloramination in carbonaceous and nitrogenous disinfection byproduct formation potentials with prolonged contact time.

    Science.gov (United States)

    Sakai, Hiroshi; Tokuhara, Shunsuke; Murakami, Michio; Kosaka, Koji; Oguma, Kumiko; Takizawa, Satoshi

    2016-01-01

    Due to decreasing water demands in Japan, hydraulic retention times of water in piped supply systems has been extended, resulting in a longer contact time with disinfectants. However, the effects of extended contact time on the formation of various disinfection byproducts (DBPs), including carbonaceous DBPs such as trihalomethane (THM) and haloacetic acid (HAA), and nitrogenous DBPs such as nitrosodimethylamine (NDMA) and nitrosomorpholine (NMor), have not yet been investigated in detail. Herein, we compared the formation of these DBPs by chlorination and chloramination for five water samples collected from rivers and a dam in Japan, all of which represent municipal water supply sources. Water samples were treated by either filtration or a combination of coagulation and filtration. Treated samples were subjected to a DBP formation potential test by either chlorine or chloramine for contact times of 1 day or 4 days. Four THM species, nine HAA species, NDMA, and NMor were measured by GC-ECD or UPLC-MS/MS. Lifetime cancer risk was calculated based on the Integrated Risk Information System unit risk information. The experiment and analysis focused on (i) prolonged contact time from 1 day to 4 days, (ii) reduction efficiency by conventional treatment, (iii) correlations between DBP formation potentials and water quality parameters, and (iv) the contribution of each species to total risk. With an increased contact time from 1 day to 4 days, THM formation increased to 420% by chloramination. Coagulation-filtration treatment showed that brominated species in THMs are less likely to be reduced. With the highest unit risk among THM species, dibromochloromethane (DBCM) showed a high correlation with bromine, but not with organic matter parameters. NDMA contributed to lifetime cancer risk. The THM formation pathway should be revisited in terms of chloramination and bromine incorporation. It is also recommended to investigate nitrosamine formation potential by

  9. [Relationship between the users' contact time in educational programs on diabetes mellitus and self-care skills and knowledge].

    Science.gov (United States)

    Maia, Mariana Almeida; Reis, Ilka Afonso; Torres, Heloísa de Carvalho

    2016-02-01

    Check the relationship between the users' contact time in educational programs and self-care and knowledge variables in diabetes mellitus. A longitudinal study with a quantitative approach with the participation, in the initial phase, of 263 users linked to Basic Health Units in Belo Horizonte, Brazil during the years 2012 and 2013. The data were collected with respect to the total contact time of the users' participation in the educational program as regards knowledge and self-care in acquired diabetes mellitus. The data were analyzed using the Student t-test for comparison of means, considering a 0.05 significance level. The final sample included 151 users. The analysis showed that the improvement in self-care scores was statistically higher during an educational intervention of eight hours or more (p-value knowledge, there was a statistically significant improvement at the end of the educational program. It was not possible to identify a value for the contact time from which there was an increase in mean scores for the ability of knowledge. To improve the effectiveness of the promotion of skills related to knowledge and self-care in diabetes mellitus, it is necessary to consider the contact time as a relevant factor of the educational program.

  10. Colon-targeted delivery of budesonide using dual pH- and time-dependent polymeric nanoparticles for colitis therapy

    Directory of Open Access Journals (Sweden)

    Naeem M

    2015-07-01

    Full Text Available Muhammad Naeem,1 Moonjeong Choi,1 Jiafu Cao,1 Yujeong Lee,1 Muhammad Ikram,2 Sik Yoon,2 Jaewon Lee,1 Hyung Ryong Moon,1 Min-Soo Kim,1 Yunjin Jung,1 Jin-Wook Yoo11College of Pharmacy, Pusan National University, Busan, 2Pusan National University School of Medicine, Yangsan, South KoreaAbstract: Single pH-dependent drug delivery systems have been widely used for colon-targeted delivery, but their efficiency is often hampered by the variation in gut pH. To overcome the limitation of single pH-dependent delivery systems, in this study, we developed and evaluated the therapeutic potential of budesonide-loaded dual pH/time-dependent nanoparticles (NPs for the treatment of colitis. Eudragit FS30D was used as a pH-dependent polymer, and Eudragit RS100 as a time-dependent controlled release polymer. Single pH-dependent NPs (pH_NPs, single time-dependent NPs (Time_NPs, and dual pH/time-dependent NPs (pH/Time_NPs were prepared using the oil-in-water emulsion method. The physicochemical properties and drug release profiles of these NPs in gastrointestinal (GI tract conditions were investigated. The therapeutic potential and in vivo distribution of the NPs were evaluated in a dextran sulfate sodium (DSS-induced colitis mice model. The pH/Time_NPs prevented a burst drug release in acidic pH conditions and showed sustained release at a colonic pH. The in vivo distribution study in the mice GI tract demonstrated that pH/Time_NPs were more efficiently delivered to the inflamed colon than pH_NPs were. Compared to the single pH_NPs-treated group, the pH/Time_NPs-treated group showed increased body weight and colon length and markedly decreased disease activity index, colon weight/length ratios, histological damage, and inflammatory cell infiltration in colon tissue. Our results demonstrate that the dual pH/time-dependent NPs are an effective oral colon-targeted delivery system for colitis therapy.Keywords: colon-specific delivery, dual-sensitive delivery

  11. Leaching of boron, arsenic and selenium from sedimentary rocks: I. Effects of contact time, mixing speed and liquid-to-solid ratio

    Energy Technology Data Exchange (ETDEWEB)

    Tabelin, Carlito Baltazar, E-mail: carlito@trans-er.eng.hokudai.ac.jp [Laboratory of Soil Environment Engineering, Faculty of Engineering, Hokkaido University, Sapporo (Japan); Hashimoto, Ayaka, E-mail: a.hashimoto@diaconsult.co.jp [DIA Consultants Co. Ltd., Sapporo (Japan); Igarashi, Toshifumi, E-mail: tosifumi@eng.hokudai.ac.jp [Laboratory of Groundwater and Mass Transport, Faculty of Engineering, Hokkaido University, Sapporo (Japan); Yoneda, Tetsuro, E-mail: yonet@eng.hokudai.ac.jp [Laboratory of Soil Environment Engineering, Faculty of Engineering, Hokkaido University, Sapporo (Japan)

    2014-02-01

    Sedimentary rocks of marine origin excavated in tunnel projects were recently identified as potentially hazardous because they could release significant amounts of toxic trace elements when exposed to the environment. This study investigated the leaching characteristics of B, As, Se and the major coexisting ions under various conditions to identify the factors and processes controlling their evolution in the leachate. In addition, we evaluated whether the parameters of the currently used leachability test for excavated rocks were adequate. Although the leachabilities of B, As and Se similarly increased at longer contact times, only those of B and As were influenced by the mixing speed and/or liquid-to-solid ratio (L/S). The majority of trace elements dissolved in the leachate originated from the dissolution of soluble salts formed from seawater of the Cretaceous trapped during the formation of the sedimentary rocks. Moreover, the alkaline pH of the leachates could be attributed to the simultaneous dissolutions at varying degrees of the mineral components of the rocks as well as the precipitation of clay minerals. In the leaching test of excavated rocks for regulatory purposes, the best values of contact time and mixing speed should represent conditions of the highest trace element extractabilities, which in this study were found at longer contact times ( > 48 h) and the fastest mixing speed (200 rpm). The most appropriate L/S for the leaching test is 10 because it was around this L/S that the extractabilities and leaching concentrations of the trace elements were simultaneously observed at their highest values. - Highlights: • B, As and Se leaching increased with time reaching equilibrium after ca. 48 h. • Effect of L/S on B and As leaching was strong but not that much on Se. • All leachates were alkaline regardless of the contact time, mixing speed and L/S. • Na{sup +}–SO{sub 4}{sup 2−} and Na{sup +}–HCO{sub 3}{sup −} type leachates were produced

  12. Sorption and precipitation of Mn2+ by viable and autoclaved Shewanella putrefaciens: Effect of contact time

    NARCIS (Netherlands)

    Chubar, N.; Visser, T.; Avramut, C.; de Waard, H.C.

    2013-01-01

    The sorption of Mn(II) by viable and inactivated cells of Shewanella putrefaciens, a non-pathogenic, facultative anaerobic, gram-negative bacterium characterised as a Mn(IV) and Fe(III) reducer, was studied under aerobic conditions, as a function of pH, bacterial density and metal loading. During

  13. Dual Time Stepping Algorithms With the High Order Harmonic Balance Method for Contact Interfaces With Fretting-Wear

    CERN Document Server

    Salles, Loic; Gouskov, Alexandre; Jean, Pierrick; Thouverez, Fabrice

    2014-01-01

    Contact interfaces with dry friction are frequently used in turbomachinery. Dry friction damping produced by the sliding surfaces of these interfaces reduces the amplitude of bladed-disk vibration. The relative displacements at these interfaces lead to fretting-wear which reduces the average life expectancy of the structure. Frequency response functions are calculated numerically by using the multi-harmonic balance method (mHBM). The dynamic Lagrangian frequency-time method is used to calculate contact forces in the frequency domain. A new strategy for solving nonlinear systems based on dual time stepping is applied. This method is faster than using Newton solvers. It was used successfully for solving Nonlinear CFD equations in the frequency domain. This new approach allows identifying the steady state of worn systems by integrating wear rate equations a on dual time scale. The dual time equations are integrated by an implicit scheme. Of the different orders tested, the first order scheme provided the best re...

  14. Stability and Relative Stability of Linear Systems with Many Constant Time Delays. Ph.D. Thesis

    Science.gov (United States)

    Barker, Larry Keith

    1976-01-01

    A method of determining the stability of linear systems with many constant time delays is developed. This technique, an extension of the tau-decomposition method, is used to examine not only the stability but also the relative stability of retarded systems with many delays and a class of neutral equations with one delay. Analytical equations are derived for partitioning the delay space of a retarded system with two time delays. The stability of the system in each of the regions defined by the partitioning curves in the parameter plane is determined using the extended tau-decomposition method. In addition, relative stability boundaries are defined using the extended tau-decompositon method in association with parameter plane techniques. Several applications of the extended tau-decomposition method are presented and compared with stability results obtained from other analyses. In all cases the results obtained using the method outlined herein coincide with and extend those of previous investigations. The extended tau-decomposition method applied to systems with time delays requires less computational effort and yields more complete stability analyses than previous techniques.

  15. A PERISHABLE INVENTORY SYSTEM WITH SERVICE FACILITIES, MAP ARRIVALS AND PH - SERVICE TIMES

    Institute of Scientific and Technical Information of China (English)

    Paul MANUEL; B.SIVAKUMAR; G.ARIVARIGNAN

    2007-01-01

    We consider a continuous review perishable (s,S) inventory system with a service facility consisting of a waiting hall of finite capacity and a single server.We assume two types of customers,ordinary and negative,arrive according to a Markovian Arrival Process (MAP).An ordinary customer joins the queue and a negative customer instead of joining the queue removes one ordinary customer from the queue.The removal rule adopted in this paper is RCE (removal of a customer from the end).The individual customer's unit demand is satisfied after a random time of service which is assumed to have a phase-type distribution.The life time of each item and the lead time of the reorders have been assumed to be independent exponential distributions.The joint probability distribution of the number of customers in the system and the inventory level is obtained for the steady state case.Various stationary system performance measures are computed and the total expected cost rate is calculated.The results are illustrated numerically.

  16. Exploring the physiologic role of human gastroesophageal reflux by analyzing time-series data from 24-h gastric and esophageal pH recordings.

    Science.gov (United States)

    Lu, Luo; Mu, John C; Sloan, Sheldon; Miner, Philip B; Gardner, Jerry D

    2014-07-16

    Our previous finding of a fractal pattern for gastric pH and esophageal pH plus the statistical association of sequential pH values for up to 2 h led to our hypothesis that the fractal pattern encodes information regarding gastric acidity and that depending on the value of gastric acidity, the esophagus can signal the stomach to alter gastric acidity by influencing gastric secretion of acid or bicarbonate. Under our hypothesis values of gastric pH should provide information regarding values of esophageal pH and vice versa. We used vector autoregression, a theory-free set of inter-related linear regressions used to measure relationships that can change over time, to analyze data from 24-h recordings of gastric pH and esophageal pH. We found that in pH records from normal subjects, as well as from subjects with gastroesophageal reflux disease alone and after treatment with a proton pump inhibitor, gastric pH values provided important information regarding subsequent values of esophageal pH and values of esophageal pH provided important information regarding subsequent values of gastric pH. The ability of gastric pH and esophageal pH to provide information regarding subsequent values of each other was reduced in subjects with gastroesophageal reflux disease compared to normal subjects. Our findings are consistent with the hypothesis that depending on the value of gastric acidity, the esophagus can signal the stomach to alter gastric acidity, and that this ability is impaired in subjects with gastroesophageal reflux disease.

  17. Tenderness, pH and Water Activity (Aw of Spices Dried Meat on Various Concentrate of Ginger Extract (Zingiber Officinale Roscoe and Different Soaking Time

    Directory of Open Access Journals (Sweden)

    Akhadiyah Afrila

    2012-09-01

    Full Text Available The objectives of current research were to find out the concentrate of Ginger extract (Zingiber officinale Roscoe and different soaking time of to tenderness, pH, and water activity (Aw, microbial count and sensory evaluation of spices dried meat. The result showed that higher the ginger extract (Zingiber officinale Roscoe concentrate and longer the soaking time, it would give more tenderness, pH, and water activity (Aw to spices dried meat with 15% ginger extract (Zingiber officinale Roscoe extract and 20 minutes length of soaking time. Key Words : Dendeng, ginger, soaking time, tenderness, pH and Aw

  18. Time trends of contact allergy to the European baseline series in Lithuania.

    Science.gov (United States)

    Linauskienė, Kotryna; Malinauskienė, Laura; Blažienė, Audra

    2017-06-01

    Monitoring trends of positive patch test reactions is useful for epidemiological surveillance and contact allergy prevention, and has not previously been reported in Lithuania. To examine and compare changes in the prevalence of contact allergy to European baseline series allergens in adults with suspected contact dermatitis during a 9-year period. In this retrospective study, patch test results of 297 consecutive patients, tested with the European baseline series in 2014-2015, were analysed and compared with the data published earlier in Lithuania. The most common allergens were nickel sulfate (30.6%), methylisothiazolinone (MI) (13.5%), methylchloroisothiazolinone (MCI)/MI (7.4%), potassium dichromate (6.1%), cobalt chloride (6.1%), Myroxylon pereirae resin (5.4%), p-phenylenediamine (5.4%), fragrance mix I (4.7%), formaldehyde (4.4%), and methyldibromo glutaronitrile (3.7%). Increases in the prevalence of sensitization to MCI/MI (2.3% in 2006-2008 and 7.4% in 2014-2015; p < 0.0001) and nickel sulfate (16.4% in 2006-2008 and 30.6% in 2014-2015; p < 0.0001) and decreases in the prevalence of sensitization to paraben mix (3.2% in 2006-2008 and 0.3% in 2014-2015; p = 0.006) were observed. Prevalences for the other allergens remained stable or showed a decreasing trend (Myroxylon pereirae resin; p = 0.06). This study provides current information on the prevalence of contact allergy in Lithuania. Changing trends in sensitivity to some allergens probably reflect changes in exposure. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Time Domain Modeling and Analysis of Dynamic Gear Contact Force in a Wind Turbine Gearbox with Respect to Fatigue Assessment

    Directory of Open Access Journals (Sweden)

    Torgeir Moan

    2012-11-01

    Full Text Available The gearbox is one of the most expensive components of the wind turbine system. In order to refine the design and hence increase the long-term reliability, there has been increasing interest in utilizing time domain simulations in the prediction of gearbox design loads. In this study, three problems in time domain based gear contact fatigue analysis under dynamic conditions are discussed: (1 the torque reversal problem under low wind speed conditions, (2 statistical uncertainty effects due to time domain simulations and (3 simplified long term contact fatigue analysis of the gear tooth under dynamic conditions. Several recommendations to deal with these issues are proposed based on analyses of the National Renewable Energy Laboratory’s 750 kW land-based Gearbox Reliability Collaborative wind turbine.

  20. Time-Transient Characteristics of a Point-Contact-Type Peltier Device

    Science.gov (United States)

    Anzai, Toru; Yamaguchi, Shigeo

    We proposed a new type of Peltier device, and succeeded in the fabrication of the device, which we call a point-contact-type sandwich-structure (PCS). A micro-object can be cooled or heated using our fabricated device. The tip was cooled through the Peltier effect, and a tip temperature of -36.3°C was achieved at a current of 28 A. When current was reversed, the tip was heated and the maximum tip temperature was 251.5°C at a current of 20 A. The PCS Peltier device can be useful in medical treatment and bioelectronics.

  1. Characterizing time-dependent contact angles for sands hydrophobized with oleic and stearic acids

    DEFF Research Database (Denmark)

    Subedi, S; Kawamoto, K; Jayarathna, L

    2012-01-01

    -frequency precipitation. A potential solution is to alter soil grain surfaces to become water repellent by mixing or coating the soil cover material with hydrophobic agents (HAs). In this study, hydrophobic CBs comprised of sands mixed with environmentally friendly HAs (oleic acid [OA] and stearic acid [SA]) were studied....... Water repellency (WR) characteristics for hydrophobized sand samples with different HA contents and representing different coating methods (mixing in and solvent aided) were measured. Initial contact angles (αi) for OA-coated samples sharply increased with increasing HA content and reached peak values...

  2. Determination of time-varying contact length, friction force, torque and forces at the bearings in a helical gear system

    Science.gov (United States)

    Kar, Chinmaya; Mohanty, A. R.

    2008-01-01

    This paper deals with determining various time-varying parameters that are instrumental in introducing noise and vibration in a helical gear system. The most important parameter is the contact line variation, which subsequently induces friction force variation, frictional torque variation and variation in the forces at the bearings. The contact line variation will also give rise to gear mesh stiffness and damping variations. All these parameters are simulated for a defect-free and two defective cases of a helical gear system. The defective cases include one tooth missing and two teeth missing in the helical gear. The algorithm formulated in this paper is found to be simple and effective in determining the time-varying parameters.

  3. Time-to-Credit Gender Inequities of First-Year PhD Students in the Biological Sciences

    Science.gov (United States)

    Feldon, David F.; Peugh, James; Maher, Michelle A.; Roksa, Josipa; Tofel-Grehl, Colby

    2017-01-01

    Equitable gender representation is an important aspect of scientific workforce development to secure a sufficient number of individuals and a diversity of perspectives. Biology is the most gender equitable of all scientific fields by the marker of degree attainment, with 52.5% of PhDs awarded to women. However, equitable rates of degree completion do not translate into equitable attainment of faculty or postdoctoral positions, suggesting continued existence of gender inequalities. In a national cohort of 336 first-year PhD students in the biological sciences (i.e., microbiology, cellular biology, molecular biology, developmental biology, and genetics) from 53 research institutions, female participants logged significantly more research hours than males and were significantly more likely than males to attribute their work hours to the demands of their assigned projects over the course of the academic year. Despite this, males were 15% more likely to be listed as authors on published journal articles, indicating inequality in the ratio of time to credit. Given the cumulative advantage that accrues for students who publish early in their graduate careers and the central role that scholarly productivity plays in academic hiring decisions, these findings collectively point to a major potential source of persisting underrepresentation of women on university faculties in these fields. PMID:28130271

  4. Time-To-Treatment of Acute Coronary Syndrome and Unit of First Contact in the ERICO Study

    Science.gov (United States)

    dos Santos, Rafael Caire de Oliveira; Goulart, Alessandra Carvalho; Kisukuri, Alan Loureiro Xavier; Brandão, Rodrigo Martins; Sitnik, Debora; Staniak, Henrique Lane; Bittencourt, Marcio Sommer; Lotufo, Paulo Andrade; Bensenor, Isabela Martins; Santos, Itamar de Souza

    2016-01-01

    Background To the best of our knowledge, there are no studies evaluating the influence of the unit of the first contact on the frequency and time of pharmacological treatment during an acute coronary syndrome (ACS) event. Objectives The main objective was to investigate if the unit of first contact influenced the frequency and time of aspirin treatment in the Strategy of Registry of Acute Coronary Syndrome (ERICO) study. Methods We analyzed the pharmacological treatment time in 830 ERICO participants - 700 individuals for whom the hospital was the unit of first contact and 130 who initially sought primary care units. We built logistic regression models to study whether the unit of first contact was associated with a treatment time of less than three hours. Results Individuals who went to primary care units received the first aspirin dose in those units in 75.6% of the cases. The remaining 24.4% received aspirin at the hospital. Despite this finding, individuals from primary care still had aspirin administered within three hours more frequently than those who went to the hospital (76.8% vs 52.6%; p<0.001 and 100% vs. 70.7%; p=0.001 for non ST-elevation ACS and ST-elevation myocardial infarction, respectively). In adjusted models, individuals coming from primary care were more likely to receive aspirin more quickly (odds ratio: 3.66; 95% confidence interval: 2.06-6.51). Conclusions In our setting, individuals from primary care were more likely to receive aspirin earlier. Enhancing the ability of primary care units to provide early treatment and safe transportation may be beneficial in similar settings. PMID:27849262

  5. Benzalkonium chloride and sulfamethoxazole adsorption onto natural clinoptilolite: effect of time, ionic strength, pH and temperature.

    Science.gov (United States)

    Farías, Tania; de Ménorval, Louis Charles; Zajac, Jerzy; Rivera, Aramis

    2011-11-15

    The influence of different physical factors on the adsorption of the cationic surfactant benzalkonium chloride (BC) and the model drug sulfamethoxazole by a purified natural clinoptilolite (NZ) has been studied in order to employ zeolite-surfactant-drug composites as drug deliverer. It has been demonstrated that the adsorption of BC and sulfamethoxazole onto NZ depends of the time, the temperature, the ionic strength and the pH of the aqueous medium. The optimal conditions for the preparation of the zeolite-surfactant and zeolite-surfactant-drug composite materials are established. The results of the composite characterization support the presence of BC and sulfamethoxazole, as well as the structural stability of NZ during the treatments performed. The release experiments in acid medium demonstrate that the adsorption of sulfamethoxazole is reversible. It is also confirmed that the drug release profile corresponds to a diffusion or zero-order mechanism as a function of the compression pressure.

  6. Gel-based phosphoproteomics analysis of sarcoplasmic proteins in postmortem porcine muscle with pH decline rate and time differences

    DEFF Research Database (Denmark)

    Huang, Honggang; Larsen, Martin Røssel; Karlsson, Anders H

    2011-01-01

    Meat quality development is highly influenced by the pH decline caused by the postmortem (PM) glycolysis. Protein phosphorylation is an important mechanism in regulating the activity of glycometabolic enzymes. Here, a gel-based phosphoproteomic study was performed to analyze the protein...... phosphorylation in sarcoplasmic proteins from three groups of pigs with different pH decline rates from PM 1 to 24¿h. Globally, the fast pH decline group had the highest phosphorylation level at PM 1¿h, but lowest at 24¿h, whereas the slow pH decline group showed the reverse case. The same pattern was also...... observed in most individual bands in 1-DE. The protein phosphorylation levels of 12 bands were significantly affected by the synergy effects of pH and time (p...

  7. Time-to-Credit Gender Inequities of First-Year PhD Students in the Biological Sciences.

    Science.gov (United States)

    Feldon, David F; Peugh, James; Maher, Michelle A; Roksa, Josipa; Tofel-Grehl, Colby

    2017-01-01

    Equitable gender representation is an important aspect of scientific workforce development to secure a sufficient number of individuals and a diversity of perspectives. Biology is the most gender equitable of all scientific fields by the marker of degree attainment, with 52.5% of PhDs awarded to women. However, equitable rates of degree completion do not translate into equitable attainment of faculty or postdoctoral positions, suggesting continued existence of gender inequalities. In a national cohort of 336 first-year PhD students in the biological sciences (i.e., microbiology, cellular biology, molecular biology, developmental biology, and genetics) from 53 research institutions, female participants logged significantly more research hours than males and were significantly more likely than males to attribute their work hours to the demands of their assigned projects over the course of the academic year. Despite this, males were 15% more likely to be listed as authors on published journal articles, indicating inequality in the ratio of time to credit. Given the cumulative advantage that accrues for students who publish early in their graduate careers and the central role that scholarly productivity plays in academic hiring decisions, these findings collectively point to a major potential source of persisting underrepresentation of women on university faculties in these fields. © 2017 D. F. Feldon et al. CBE—Life Sciences Education © 2017 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  8. Gene expression time course in the human skin during elicitation of allergic contact dermatitis

    DEFF Research Database (Denmark)

    Pedersen, Malene; Skov, Lone; Menné, Torkil

    2007-01-01

    and activator of transcription and small/mothers against decepentaplegic (SMAD) transcription factors in the late time-point gene expression patterns. Concerning specific genes, the homeostatic chemokine CCL19 was unexpectedly found to be highly expressed in cells scattered in the deep dermis of the late time...

  9. Effect of the gastrointestinal environment on pH homeostasis of Lactobacillus plantarum and Lactobacillus brevis cells as measured by real-time fluorescence ratio-imaging microscopy.

    Science.gov (United States)

    Ramos, Cíntia Lacerda; Thorsen, Line; Ryssel, Mia; Nielsen, Dennis S; Siegumfeldt, Henrik; Schwan, Rosane Freitas; Jespersen, Lene

    2014-04-01

    In the present work, an in vitro model of the gastrointestinal tract (GIT) was developed to obtain real-time observations of the pH homeostasis of single cells of probiotic Lactobacillus spp. strains as a measure of their physiological state. Changes in the intracellular pH (pHi) were determined using fluorescence ratio imaging microscopy (FRIM) for potential probiotic strains of Lactobacillus plantarum UFLA CH3 and Lactobacillus brevis UFLA FFC199. Heterogeneous populations were observed, with pHi values ranging from 6.5 to 7.5, 3.5 to 5.6 and 6.5 to 8.0 or higher during passage of saliva (pH 6.4), gastric (pH 3.5) and intestinal juices (pH 6.4), respectively. When nutrients were added to gastric juice, the isolate L. brevis significantly decreased its pH(i) closer to the extracellular pH (pH(ex)) than in gastric juice without nutrients. This was not the case for L. plantarum. This study is the first to produce an in vitro GIT model enabling real-time monitoring of pH homeostasis of single cells in response to the wide range of pH(ex) of the GIT. Furthermore, it was possible to observe the heterogeneous response of single cells. The technique can be used to determine the survival and physiological conditions of potential probiotics and other microorganisms during passage through the GIT.

  10. Oxytocin increases eye contact during a real-time, naturalistic social interaction in males with and without autism.

    Science.gov (United States)

    Auyeung, B; Lombardo, M V; Heinrichs, M; Chakrabarti, B; Sule, A; Deakin, J B; Bethlehem, R A I; Dickens, L; Mooney, N; Sipple, J A N; Thiemann, P; Baron-Cohen, S

    2015-02-10

    Autism spectrum conditions (autism) affect ~1% of the population and are characterized by deficits in social communication. Oxytocin has been widely reported to affect social-communicative function and its neural underpinnings. Here we report the first evidence that intranasal oxytocin administration improves a core problem that individuals with autism have in using eye contact appropriately in real-world social settings. A randomized double-blind, placebo-controlled, within-subjects design is used to examine how intranasal administration of 24 IU of oxytocin affects gaze behavior for 32 adult males with autism and 34 controls in a real-time interaction with a researcher. This interactive paradigm bypasses many of the limitations encountered with conventional static or computer-based stimuli. Eye movements are recorded using eye tracking, providing an objective measurement of looking patterns. The measure is shown to be sensitive to the reduced eye contact commonly reported in autism, with the autism group spending less time looking to the eye region of the face than controls. Oxytocin administration selectively enhanced gaze to the eyes in both the autism and control groups (transformed mean eye-fixation difference per second=0.082; 95% CI:0.025-0.14, P=0.006). Within the autism group, oxytocin has the most effect on fixation duration in individuals with impaired levels of eye contact at baseline (Cohen's d=0.86). These findings demonstrate that the potential benefits of oxytocin in autism extend to a real-time interaction, providing evidence of a therapeutic effect in a key aspect of social communication.

  11. Live Fast, Die Young: Optimizing Retention Times in High-Rate Contact Stabilization for Maximal Recovery of Organics from Wastewater.

    Science.gov (United States)

    Meerburg, Francis A; Boon, Nico; Van Winckel, Tim; Pauwels, Koen T G; Vlaeminck, Siegfried E

    2016-09-01

    Wastewater is typically treated by the conventional activated sludge process, which suffers from an inefficient overall energy balance. The high-rate contact stabilization (HiCS) has been proposed as a promising primary treatment technology with which to maximize redirection of organics to sludge for subsequent energy recovery. It utilizes a feast-famine cycle to select for bioflocculation, intracellular storage, or both. We optimized the HiCS process for organics recovery and characterized different biological pathways of organics removal and recovery. A total of eight HiCS reactors were operated at 15 °C at short solids retention times (SRT; 0.24-2.8 days), hydraulic contact times (tc; 8 and 15 min), and stabilization times (ts; 15 and 40 min). At an optimal SRT between 0.5 and 1.3 days and tc of 15 min and ts of 40 min, the HiCS system oxidized only 10% of influent chemical oxygen demand (COD) and recovered up to 55% of incoming organic matter into sludge. Storage played a minor role in the overall COD removal, which was likely dominated by aerobic biomass growth, bioflocculation onto extracellular polymeric substances, and settling. The HiCS process recovers enough organics to potentially produce 28 kWh of electricity per population equivalent per year by anaerobic digestion and electricity generation. This inspires new possibilities for energy-neutral wastewater treatment.

  12. Real-time image processing for non-contact monitoring of dynamic displacements using smartphone technologies

    Science.gov (United States)

    Min, Jae-Hong; Gelo, Nikolas J.; Jo, Hongki

    2016-04-01

    The newly developed smartphone application, named RINO, in this study allows measuring absolute dynamic displacements and processing them in real time using state-of-the-art smartphone technologies, such as high-performance graphics processing unit (GPU), in addition to already powerful CPU and memories, embedded high-speed/ resolution camera, and open-source computer vision libraries. A carefully designed color-patterned target and user-adjustable crop filter enable accurate and fast image processing, allowing up to 240fps for complete displacement calculation and real-time display. The performances of the developed smartphone application are experimentally validated, showing comparable accuracy with those of conventional laser displacement sensor.

  13. Photometric Investigation and Possible Light-Time Effect in the Orbital Period of a Marginal Contact System, CW Cassiopeiae

    Science.gov (United States)

    Jiang, Tian-Yu; Li, Li-Fang; Han, Zhan-Wen; Jiang, Deng-Kai

    2010-04-01

    The first complete charge-coupled device (CCD) light curves in B and V passbands of a neglected contact binary system, CW Cassiopeiae (CW Cas), are presented. They were analyzed simultaneously by using the Wilson and Devinney (WD) code (1971, ApJ, 166, 605). The photometric solution indicates that CW Cas is a W-type W UMa system with a mass ratio of m2/m1 2.234, and that it is in a marginal contact state with a contact degree of ˜6.5% and a relatively large temperature difference of ˜327K between its two components. Based on the minimum times collected from the literature, together with the new ones obtained in this study, the orbital period changes of CW Cas were investigated in detail. It was found that a periodical variation overlaps with a secular period decrease in its orbital period. The long-term period decrease with a rate of dP/dt = -3.44 × 10-8d yr-1 can be interpreted either by mass transfer from the more-massive component to the less-massive with a rate of dm2/dt = -3.6 × 10-8M⊙ yr-1, or by mass and angular-momentum losses through magnetic braking due to a magnetic stellar wind. A low-amplitude cyclic variation with a period of T = 63.7 yr might be caused by the light-time effect due to the presence of a third body.

  14. The time-dose-response relationship for elicitation of contact dermatitis in isoeugenol allergic individuals

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Johansen, Jeanne Duus; Bruze, M

    2001-01-01

    and was 15 days for the 0.05% solution. There was a highly significant correlation between the patients' patch test threshold and the number of days until a positive ROAT. In conclusion, the time until an isoeugenol allergic individual reacts in a ROAT depends on the individual sensitivity as well...

  15. Effects of Different Distributions of Training Time on the Acquisition of Contact Flying Skills

    Science.gov (United States)

    1981-07-01

    Alexandria, VA: U.S. Army Research TF-1tute for the Behavioral and Social Sciences, September 1978. Seltzer, L. Z. A study of the effect of time on the...CO4PLIES WITH MESSAGES WHILE (w PERFORtHING OTHER TASKS COMMINTS : C-48 SECURING AIRPLANE PROCEDURES SECURING AIRPLANE PROCEDURES CORRECT PARKING BRAKE

  16. Interaction of quinine sulfate with anionic micelles of sodium dodecylsulfate: A time-resolved fluorescence spectroscopy at different pH

    Science.gov (United States)

    Joshi, Sunita; Pant, Debi D.

    2015-09-01

    Photophysical behavior and rotational relaxation dynamics of quinine sulfate (QS) in anionic surfactant, sodium dodecylsulfate (SDS) at different pH have been studied using steady state and time resolved fluorescence spectroscopy. It has been observed that the cationic form of quinine sulfate (at pH 2) forms a fluorescent ion pair complex with the surfactant molecules at lower concentrations of surfactant. However, for higher concentrations of SDS, the probe molecules bind strongly with the micelles and reside at the water-micelle interface. At pH 7, QS is singly protonated in bulk aqueous solution. At lower concentrations of SDS aggregation between probe and surfactant molecules has been observed. However, for higher concentrations of SDS, an additional fluorescence peak corresponding to dicationic form of QS appears and this has been attributed to double protonation of the QS molecule in micellar solution. At pH 7, in the presence of SDS micelles, the photophysical properties of QS showed substantial changes compared to that in the bulk water solution. At pH 12, an increase in fluorescence intensity and lifetime has been observed and this has been attributed to the increase in radiative rate due to the incorporation of QS at the micelle-water interface. The local pH at micellar surface has been found different from the pH of bulk solution.

  17. Accuracy of PARTwear Inertial Sensor and Optojump Optical Measurement System for Measuring Ground Contact Time During Running.

    Science.gov (United States)

    Ammann, Rahel; Taube, Wolfgang; Wyss, Thomas

    2016-07-01

    Ammann, R, Taube, W, and Wyss, T. Accuracy of PARTwear inertial sensor and Optojump optical measurement system for measuring ground contact time during running. J Strength Cond Res 30(7): 2057-2063, 2016-The aim of this study was to validate the detection of ground contact time (GCT) during running in 2 differently working systems: a small inertial measurement sensor, PARTwear (PW), worn on the shoe laces, and the optical measurement system, Optojump (OJ), placed on the track. Twelve well-trained subjects performed 12 runs each on an indoor track at speeds ranging from 3.0 to 9.0 m·s. GCT of one step per run (total 144) was simultaneously obtained by the PW, the OJ, and a high-speed video camera (HSC), whereby the latter served as reference system. The sampling rate was 1,000 Hz for all methods. Compared with the HSC, the PW and the OJ systems underestimated GCT by -1.3 ± 6.1% and -16.5 ± 6.7% (p-values ≤ 0.05), respectively. The intraclass correlation coefficients between PW and HSC and between OJ and HSC were 0.984 and 0.853 (p-values measurement systems.

  18. Bravo capsule system optimizes intragastric pH monitoring over prolonged time: Effects of ghrelin on gastric acid and hormone secretion in the rat

    Institute of Scientific and Technical Information of China (English)

    Tobias Rudholm; Per Mikael Hellstrom; Elvar Theodorsson; Colin Allan Campbell; Peter Geoffrey McLean; Erik Naslund

    2008-01-01

    AIM: To evaluate measurements of intragastric pH with the Bravo capsule system over a prolonged time. METHODS: A Bravo capsule was placed inside the rat gastric body and pH was studied for periods up to five consecutive days. For comparison, a gastric fistula model was used. Effects of ghrelin and esomeprazole, with or without pentagastrin, on gastric pH were studied. In addition, effects of esomeprazole on plasma ghrelin, gastrin and somatostatin were analyzed. RESULTS: All rats recovered after surgery. The average 24-h pH during free feeding was 2.3±0.1 (η = 20) with a variation of 18%±6% over 5 d. Ghrelin, 2400 pmol/kg, t.i.d, increased pH from 1.7± 0.1 to 3.1±0.3 (P<0.01) as recorded with the Bravo system. After esomeprazole (1 mg/kg, 3 mg/kg and 5 mg/kg) there was a dose-dependent pH increase of maximally 3.4±0.1, with day-to-day variation over the entire period of 8%±3%. The fistula and pH studies generated similar results. Acid inhibition with esomeprazole increased plasma ghrelin from 10±2 pmol/L to 65±26 pmol/L (P<0.001), and somatostatin from 10±2 pmol/L to 67±18 pmol/L (P <0.001). CONCLUSION: pH measurements with the Bravo capsule are reliable, and comparable to those of the gastric fistula model. The Bravo system optimizes accurate intragastric pH monitoring over prolonged periods and allows both short- and long-term evaluation of effects of drugs and hormones.

  19. Photoinduced superhydrophilicity: a kinetic study of time dependent photoinduced contact angle changes on TiO2 surfaces.

    Science.gov (United States)

    Foran, Philip S; Boxall, Colin; Denison, Kieth R

    2012-12-21

    Transparent TiO(2) thin films were prepared on quartz substrates via a reverse micelle, sol-gel, spin-coating technique. The time dependence of the TiO(2) film photoinduced superhydrophilicity (PISH) was measured by goniometric observation of the contact angle, θ, of sessile water drops at the film surfaces. In these measurements, the TiO(2) substrate was illuminated by 315 nm light and drops were sequentially applied at a range of illumination times. Using a model for the wetting of heterogeneous surfaces derived by Israelachvili and Gee, these measurements were used to calculate the time dependence of f(2), the fractional surface coverage of the TiO(2) surface by adventitious contaminating organics (Israelachvili, J. N.; Gee, M. L. Contact angles on chemically heterogeneous surfaces. Langmuir 1989, 5, 288). Extending this model to include a Langmuir-Hinshelwood based kinetic analysis of f(2) as a function of time allowed for calculation of an expected value for θ immediately prior to illumination, that is, at illumination time t = 0. Such expected values of θ at t = 0 were calculated using two possible values of θ(1), the contact angle on a pristine unilluminated homogeneous TiO(2) surface: (i) θ(1) = 4° as suggested by, inter alia, Zubkov et al. (Zubkov, T.; Stahl, D.; Thompson, T. L.; Panayotov, D.; Diwald, O.; Yates, J. T. Ultraviolet Light-Induced Hydrophilicity Effect on TiO(2)(110)(1 × 1). Dominant Role of the Photooxidation of Adsorbed Hydrocarbons Causing Wetting by Water Droplets. J. Phys. Chem. B2005, 109, 15454); and (ii) where θ(1) = 25°, as suggested by Fujishima et al., representative of a more hydrophobic homogeneous TiO(2) surface that reconstructs upon exposure to ultraband gap illumination into a hydrophilic surface where θ(1) → 0° (Fujishima, A.; Zhang, X.; Tryk, D. A. TiO(2) photocatalysis and related surface phenomena Surf. Sci. Rep.2008, 63, 515). Analysis of data from our experiments and from selected literature sources

  20. Corrosion studies with high burnup light water reactor fuel. Release of nuclides into simulated groundwater during accumulated contact time of up to two years

    Energy Technology Data Exchange (ETDEWEB)

    Zwicky, Hans-Urs (Zwicky Consulting GmbH, Remigen (Switzerland)); Low, Jeanett; Ekeroth, Ella (Studsvik Nuclear AB, Nykoeping (Sweden))

    2011-03-15

    period, water samples are taken for different analyses and for pH and carbonate determination. The fuel sample is placed in a new flask with fresh synthetic groundwater for the next contact period. Release fractions are calculated by dividing the total amount of a nuclide of concern in the analysed solution by the total amount in the corroded fuel sample. Cumulative release fractions are the sum of release fractions up to a certain cumulative contact time. Release rates are calculated by dividing release fractions by the length of the contact period of concern. Caesium and rubidium were released to a significantly larger extent in the high burnup samples, compared to the Series 11 experiments. This is probably more a consequence of different operating conditions than of burnup

  1. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... like a suction cup." Halloween is a popular time for people to use colored contact lenses to ... wear costume contact lenses for Halloween or any time of year, follow these guidelines: Get an eye ...

  2. SHORT CONTACT TIME DIRECT COAL LIQUEFACTION USING A NOVEL BATCH REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    Michael T. Klein; William H. Calkins

    1997-10-29

    The overall goal of this research is to develop an understanding of the Direct Coal Liquefaction process at the molecular level. Many approaches have been used to study this process including kinetic studies, study of the liquefaction products, study of the effect of reaction variables, such as temperature, solvent type and composition, the changing nature and composition of the coal during liquefaction, and the distribution in the liquefaction products of the hydrogen consumed. While all these studies have contributed to our growing knowledge of the liquefaction process, an adequate understanding of direct liquefaction still eludes us. This is due to many reasons including: the complexity and variable nature of coal itself and the many different chemical reactions which are occurring simultaneously during direct coal liquefaction. We believe that a study of the liquefaction process at the very early stages will avoid the complexities of secondary reactions associated with free radical high temperature processes that are clearly involved in direct coal liquefaction. This prompted us to devise a reactor system which avoids long heat up and cool-down times associated with previous kinetic studies, and allows kinetic measurements even at as short as the first few seconds of the liquefaction reaction.

  3. Operating envelope of a short contact time fuel reformer for propane catalytic partial oxidation

    Science.gov (United States)

    Waller, Michael G.; Walluk, Mark R.; Trabold, Thomas A.

    2015-01-01

    Fuel cell technology has yet to realize widespread deployment, in part because of the hydrogen fuel infrastructure required for proton exchange membrane systems. One option to overcome this barrier is to produce hydrogen by reforming propane, which has existing widespread infrastructure, is widely used by the general public, easily transported, and has a high energy density. The present work combines thermodynamic modeling of propane catalytic partial oxidation (cPOx) and experimental performance of a Precision Combustion Inc. (PCI) Microlith® reactor with real-time soot measurement. Much of the reforming research using Microlith-based reactors has focused on fuels such as natural gas, JP-8, diesel, and gasoline, but little research on propane reforming with Microlith-based catalysts can be found in literature. The aim of this study was to determine the optimal operating parameters for the reformer that maximizes efficiency and minimizes solid carbon formation. The primary parameters evaluated were reformate composition, carbon concentration in the effluent, and reforming efficiency as a function of catalyst temperature and O2/C ratio. Including the lower heating values for product hydrogen and carbon monoxide, efficiency of 84% was achieved at an O2/C ratio of 0.53 and a catalyst temperature of 940 °C, resulting in near equilibrium performance. Significant solid carbon formation was observed at much lower catalyst temperatures, and carbon concentration in the effluent was determined to have a negative linear relationship at T reactor displayed good stability during more than 80 experiments with temperature cycling from 360 to 1050 °C.

  4. Contact dermatitis

    Science.gov (United States)

    Dermatitis - contact; Allergic dermatitis; Dermatitis - allergic; Irritant contact dermatitis; Skin rash - contact dermatitis ... There are 2 types of contact dermatitis. Irritant dermatitis: This ... with acids, alkaline materials such as soaps and detergents , ...

  5. Local activation time sampling density for atrial tachycardia contact mapping: how much is enough?

    Science.gov (United States)

    Williams, Steven E; Harrison, James L; Chubb, Henry; Whitaker, John; Kiedrowicz, Radek; Rinaldi, Christopher A; Cooklin, Michael; Wright, Matthew; Niederer, Steven; O'Neill, Mark D

    2017-04-03

    Local activation time (LAT) mapping forms the cornerstone of atrial tachycardia diagnosis. Although anatomic and positional accuracy of electroanatomic mapping (EAM) systems have been validated, the effect of electrode sampling density on LAT map reconstruction is not known. Here, we study the effect of chamber geometry and activation complexity on optimal LAT sampling density using a combined in silico and in vivo approach. In vivo 21 atrial tachycardia maps were studied in three groups: (1) focal activation, (2) macro-re-entry, and (3) localized re-entry. In silico activation was simulated on a 4×4cm atrial monolayer, sampled randomly at 0.25-10 points/cm2 and used to re-interpolate LAT maps. Activation patterns were studied in the geometrically simple porcine right atrium (RA) and complex human left atrium (LA). Activation complexity was introduced into the porcine RA by incomplete inter-caval linear ablation. In all cases, optimal sampling density was defined as the highest density resulting in minimal further error reduction in the re-interpolated maps. Optimal sampling densities for LA tachycardias were 0.67 ± 0.17 points/cm2 (focal activation), 1.05 ± 0.32 points/cm2 (macro-re-entry) and 1.23 ± 0.26 points/cm2 (localized re-entry), P = 0.0031. Increasing activation complexity was associated with increased optimal sampling density both in silico (focal activation 1.09 ± 0.14 points/cm2; re-entry 1.44 ± 0.49 points/cm2; spiral-wave 1.50 ± 0.34 points/cm2, P density (0.61 ± 0.22 points/cm2 vs. 1.0 ± 0.34 points/cm2, P = 0.0015). Optimal sampling densities can be identified to maximize diagnostic yield of LAT maps. Greater sampling density is required to correctly reveal complex activation and represent activation across complex geometries. Overall, the optimal sampling density for LAT map interpolation defined in this study was ∼1.0-1.5 points/cm2.

  6. Real-time UV imaging identifies the role of pH in insulin dissolution behavior in hydrogel-based subcutaneous tissue surrogate

    DEFF Research Database (Denmark)

    Jensen, Sabrine S; Jensen, Henrik; Cornett, Claus;

    2015-01-01

    in the development of new protein drug formulations. Using insulin as a model compound, the aim of this work was to develop a UV imaging-based method to study the real-time dissolution and diffusion behavior of solid protein drugs under stagnant conditions in a hydrogel matrix mimicking the subcutaneous tissue....... Dissolution of proteins and peptides is a complex phenomenon as it may be coupled to the complicated acid base properties of these substances. UV imaging allowed the real-time dissolution and diffusion processes of insulin at different pH values and of different insulins to be studied. Dissolution rates were...... obtained, and the quantitative performance of the developed UV imaging method was verified. It was shown that the UV imaging dissolution method was able to differentiate between the behavior of different insulins and that human insulin dissolution was highly dependent on pH. pH effects...

  7. Over Time, How Do Post-Ph.D. Scientists Locate Teaching and Supervision within Their Academic Practice?

    Science.gov (United States)

    McAlpine, Lynn

    2014-01-01

    While building a strong research profile is usually seen as key for those seeking a traditional academic position, teaching is also understood as central to academic practice. Still, we know little of how post-Ph.D. researchers seeking academic posts locate teaching and supervision in their academic practice, nor how their views may shift as they…

  8. Time-to-Credit Gender Inequities of First-Year PhD Students in the Biological Sciences

    Science.gov (United States)

    Feldon, David F.; Peugh, James; Maher, Michelle A.; Roksa, Josipa; Tofel-Grehl, Colby

    2017-01-01

    Equitable gender representation is an important aspect of scientific workforce development to secure a sufficient number of individuals and a diversity of perspectives. Biology is the most gender equitable of all scientific fields by the marker of degree attainment, with 52.5% of PhDs awarded to women. However, equitable rates of degree completion…

  9. Time-to-Credit Gender Inequities of First-Year PhD Students in the Biological Sciences

    Science.gov (United States)

    Feldon, David F.; Peugh, James; Maher, Michelle A.; Roksa, Josipa; Tofel-Grehl, Colby

    2017-01-01

    Equitable gender representation is an important aspect of scientific workforce development to secure a sufficient number of individuals and a diversity of perspectives. Biology is the most gender equitable of all scientific fields by the marker of degree attainment, with 52.5% of PhDs awarded to women. However, equitable rates of degree completion…

  10. Effects of pH and storage time on the adhesive and rheological properties of cottonseed meal-based products

    Science.gov (United States)

    Adhesive bonding is a key factor for efficiently utilizing timber and other lignocellulosic resources. To increase the basic knowledge of cottonseed meal-based adhesives and optimize the operational parameters for practical applications, in this study, we investigated the effects of pH and storage t...

  11. Time resolved calorimetry of photo-induced folding in horse heart cytochrome c at high pH.

    Science.gov (United States)

    Word, Tarah A; Larsen, Randy W

    2017-02-01

    Here the molar volume and enthalpy changes associated with the early events in the folding of ferrocytochrome c (Cc) at high pH have been examined using time resolved photoacoustic calorimetry (PAC). The data reveal an overall volume change of 1.3 ± 0.3 mL mol(-1) and an enthalpy change of 13 ± 7 kcal mol (-1) occurring subsequent to photodissociation of the unfolded CO bound Cc species in <∼20 ns. Two additional kinetic phases are observed that are associated with non-native His binding (ΔH and ΔV of 2 ± 4 kcal mol(-1) and -0.5 mL mol(-1), τ ∼ 2.5 μs ) and Met binding (ΔH and ΔV -0.4 ± 2 kcal mol(-1) and -0.1 ± 0.1 mL mol(-1), τ∼ 660 ns). Considering only protein conformational changes (excluding volume and enthalpies associated with heme ligation events) the initial conformational event exhibits a ΔH and ΔV of 6 ± 3 kcal mol(-1) and -3±0.1 mL mol(-1), respectively, that are attributed to a small contraction of the unfolded protein. The corresponding enthalpy associated with both native and non-native ligand binding are found to be -5±4 kcal mol(-1) (Fe-Met) and +20 ± 4 kcal mol(-1) (Fe-His) with the change in volume for both phases being essential negligible. This would indicate that non-native ligand binding likely occurs from an already collapsed conformation. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Influence of 2% chlorhexidine on pH, calcium release and setting time of a resinous MTA-based root-end filling material.

    Science.gov (United States)

    Jacinto, Rogério Castilho; Linhares-Farina, Giane; Sposito, Otávio da Silva; Zanchi, César Henrique; Cenci, Maximiliano Sérgio

    2015-01-01

    The addition of chlorhexidine (CHX) to a resinous experimental Mineral Trioxide Aggregate (E-MTA) based root-end filling material is an alternative to boost its antimicrobial activity. However, the influence of chlorhexidine on the properties of this material is unclear. The aim of this study was to evaluate the influence of 2% chlorhexidine on the pH, calcium ion release and setting time of a Bisphenol A Ethoxylate Dimethacrylate/Mineral Trioxide Aggregate (Bis-EMA/MTA) based dual-cure experimental root-end filling material (E-MTA), in comparison with E-MTA without the addition of CHX and with conventional white MTA (W-MTA). The materials were placed in polyethylene tubes, and immersed in deionized water to determine pH (digital pH meter) and calcium ion release (atomic absorption spectrometry technique). The setting time of each material was analyzed using Gilmore needles. The data were statistically analyzed at a significance level of 5%. E-MTA + CHX showed an alkaline pH in the 3 h period of evaluation, the alkalinity of which decreased but remained as such for 15 days. The pH of E-MTA + CHX was higher than the other two materials after 7 days, and lower after 30 days (p MTA to levels statistically similar to W-MTA. E-MTA showed shorter initial and final setting time, compared with W-MTA (p MTA prevented setting of the material. The addition of CHX to E-MTA increased its pH and calcium ion release. However, it also prevented setting of the material.

  13. Effect of Annealing Time Process on the pH Sensitivity of Spin-coated TiO2/ ZnO Bilayer Film

    Science.gov (United States)

    Rahman, R. A.; Zulkefle, M. A.; Yusof, K. A.; Abdullah, W. F. H.; Rusop, M.; Herman, S. H.

    2015-11-01

    This paper presents an investigation on titanium dioxide (TiO2) and zinc oxide (ZnO) bilayer film, which is used as sensing membrane for extended-gate field effect transistor (EGFET) for pH sensing application. TiO2/ZnO thin films were deposited using sol-gel spin coating method on indium tin oxide (ITO) substrates. After the deposition, the bilayer films were annealed at constant temperatures which is 400 °C for 15, 30, 40 and 60 minutes. The sensitivity of the TiO2 thin film towards pH buffer solution was measured by dipping the sensing membrane in pH4, pH7 and pH10 buffer solution. By varying the annealing time, we found that the TiO2/ZnO thin film annealed at 400°C for 15 minutes gave the highest sensitivity compared to other annealing conditions, with the value of 64.87 mV/pH.

  14. Effect of the gastrointestinal environment on pH homeostasis of Lactobacillus plantarum and Lactobacillus brevis cells as measured by real-time fluorescence ratio-imaging microscopy

    DEFF Research Database (Denmark)

    Ramos, Cíntia Lacerda; Thorsen, Line; Ryssel, Mia;

    2014-01-01

    using fluorescence ratio imaging microscopy (FRIM) for potential probiotic strains of Lactobacillus plantarum UFLA CH3 and Lactobacillus brevis UFLA FFC199. Heterogeneous populations were observed, with pHi values ranging from 6.5 to 7.5, 3.5 to 5.6 and 6.5 to 8.0 or higher during passage of saliva (p......In the present work, an in vitro model of the gastrointestinal tract (GIT) was developed to obtain real-time observations of the pH homeostasis of single cells of probiotic Lactobacillus spp. strains as a measure of their physiological state. Changes in the intracellular pH (pHi) were determined......H 6.4), gastric (pH 3.5) and intestinal juices (pH 6.4), respectively. When nutrients were added to gastric juice, the isolate L. brevis significantly decreased its pHi closer to the extracellular pH (pHex) than in gastric juice without nutrients. This was not the case for L. plantarum. This study...

  15. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... popping touch. But colored contact lenses are popular year-round, not just at Halloween. But few know ... contact lenses for Halloween or any time of year, follow these guidelines: Get an eye exam from ...

  16. THE EFFECT OF CONCENTRATION OF CARRIER, pH AND TIME OF EXTRACTION ON SEPARATION'S FACTOR OF PENICILLIN G - PHENYL ACETATE BY REACTIVE EXTRACTION

    Directory of Open Access Journals (Sweden)

    Imam Santoso

    2010-06-01

    Full Text Available The aim of this research is to study the effect of concentration carrier, pH and time of extraction on separation's factor of penicillin g - phenyl acetate by reactive extraction technique. The 10 mL  aqueous  solution with variation of  pH : 5, 6 contains 0.001 M penicillin G and 0.001 M phenyl acetate has been extracted with 10 mL n-butyl acetate contains dioctylamine as carrier. Variation concentration  of carrier were 0.000; 0.002; 0.004; 0.006 and 0.008 M. Variation time of extraction were 1, 5, 10, 15 and 20 min. The penicillin G and phenyl acetate that dissolved in organic phase ha been  reextracted with 10 mL aqueous with variation of pH : 7, 8. The optimum condition obtained as follow : concentration dioctylamine was 0.002M ; pH the first phase water was 5 and the second phase water was 8 ; and the time of extraction was 10 min.   Keywords: Separation factor, Reactive extraction

  17. Early warning smartphone diagnostics for water security and analysis using real-time pH mapping

    Science.gov (United States)

    Hossain, Md. Arafat; Canning, John; Ast, Sandra; Rutledge, Peter J.; Jamalipour, Abbas

    2015-12-01

    Early detection of environmental disruption, unintentional or otherwise, is increasingly desired to ensure hazard minimization in many settings. Here, using a field-portable, smartphone fluorimeter to assess water quality based on the pH response of a designer probe, a map of pH of public tap water sites has been obtained. A custom designed Android application digitally processed and mapped the results utilizing the global positioning system (GPS) service of the smartphone. The map generated indicates no disruption in pH for all sites measured, and all the data are assessed to fall inside the upper limit of local government regulations, consistent with authority reported measurements. This implementation demonstrates a new security concept: network environmental forensics utilizing the potential of novel smartgrid analysis with wireless sensors for the detection of potential disruption to water quality at any point in the city. This concept is applicable across all smartgrid strategies within the next generation of the Internet of Things and can be extended on national and global scales to address a range of target analytes, both chemical and biological.

  18. Influences of pH and hydraulic retention time on anaerobes converting beer processing wastes into hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Lay, J.J; Tsai, C.J.; Chau, C.H.; Fan, K.S.; Chang, J.I.; Hsu, P.C. [National Kaohsiung First Univ. of Science and Technology, Kaohsiung, Taiwan (China). Energy Research Centre; Huang, C.C.; Chang, J.J. [National Hsing Univ., Taichung, Taiwan (China). Dept. of Life Sciences

    2004-07-01

    Hydrogen is considered a viable renewable energy source that may come to replace fossil fuels. Although 98 per cent of current hydrogen production is from fossil fuels, research has begun to produce hydrogen from fermentation of organic wastes. Only when this is economically achieved will the hydrogen economy become viable. Hydrogen from dark fermentation is carried out using species of the genus Clostridium. Previous studies of producing hydrogen from organic wastes indicate that the control of pH is essential. Moreover, HRT is also an important variable. In this investigation, a set of experiments with yeast obtained from beer processing wastes was performed to illuminate the effect of pH and HRT on hydrogen production. A predictive quadratic equation and response surface methodology were developed to optimize the hydrogen production rate. A pH of 5.8 and HRT of 32 hours were found optimum. The key species involved were found to be Clostridium thermocellum and Klebsiella pneumoniae. 11 refs., 2 tabs., 4 figs.

  19. Language Contact.

    Science.gov (United States)

    Nelde, Peter Hans

    1995-01-01

    Examines the phenomenon of language contact and recent trends in linguistic contact research, which focuses on language use, language users, and language spheres. Also discusses the role of linguistic and cultural conflicts in language contact situations. (13 references) (MDM)

  20. Effects of pH and sugar concentration in Zygosaccharomyces rouxii growth and time for spoilage in concentrated grape juice at isothermal and non-isothermal conditions.

    Science.gov (United States)

    Rojo, M C; Arroyo López, F N; Lerena, M C; Mercado, L; Torres, A; Combina, M

    2014-04-01

    The effect of pH (1.7-3.2) and sugar concentration (64-68 °Brix) on the growth of Zygosaccharomyces rouxii MC9 using response surface methodology was studied. Experiments were carried out in concentrated grape juice inoculated with Z. rouxii at isothermal conditions (23 °C) for 60 days. pH was the variable with the highest effect on growth parameters (potential maximum growth rate and lag phase duration), although the effect of sugar concentration were also significant. In a second experiment, the time for spoilage by this microorganism in concentrated grape juice was evaluated at isothermal (23 °C) and non-isothermal conditions, in an effort to reproduce standard storage and overseas shipping temperature conditions, respectively. Results show that pH was again the environmental factor with the highest impact on delaying the spoilage of the product. Thereby, a pH value below 2.0 was enough to increase the shelf life of the product for more than 60 days in both isothermal and non-isothermal conditions. The information obtained in the present work could be used by producers and buyers to predict the growth and time for spoilage of Z. rouxii in concentrated grape juice.

  1. Effects of quantity, quality, and contact time of dissolved organic matter on bioconcentration of benzo[a]pyrene in the nematode Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Haitzer, M.; Hoess, S. [Ludwig Maximilians Univ. Muenchen (Germany). Zoologisches Inst.]|[Inst. fuer Gewaesseroekologie und Binnenfischerei, Berlin (Germany); Burnison, B.K. [Environment Canada, Burlington, Ontario (Canada). National Water Research Inst.; Traunspurger, W. [Ludwig Maximilians Univ. Muenchen (Germany). Zoologisches Inst.; Steinberg, C.E.W. [Inst. fuer Gewaesseroekologie und Binnenfischerei, Berlin (Germany)

    1999-03-01

    Quantity and quality of dissolved organic matter (DOM) and the time allowed for DOM to interact with organic contaminants can influence their bioavailability. The authors studied the effect of natural aquatic DOM that had been in contact with benzo[a]pyrene (B[a]P) for 1 to 12 d on the bioconcentration of B[a]P in the nematode Caenorhabditis elegans. Dissolved organic matter quality and quantity was varied by using DOM from three different sources, each in three different concentrations. A model, based on the assumption that only freely dissolved B[a]P is bioavailable, was employed to estimate biologically determined partition coefficients [K{sub p}(biol.)]. Expressing the data for each combination of DOM source and contact time in a single K{sub p} (biol.) value allowed a direct comparison of the effects of different DOM qualities and contact times. The results show that the effect of DOM from a specific source was dependent on DOM quantity, but they also observed a distinct effect of DOM quality (represented by different sampling locations) on the bioconcentration of B[a]P. Contact time had no significant influence for the effects of two DOM sources on the bioconcentration of B[a]P. However, the third DOM source was significantly more effective with increased contact time, leading to lower B[a]P bioconcentration in the nematodes.

  2. Polydisperse methyl β-cyclodextrin–epichlorohydrin polymers: variable contact time 13C CP-MAS solid-state NMR characterization

    Science.gov (United States)

    Mallard, Isabelle; Baudelet, Davy; Castiglione, Franca; Ferro, Monica; Panzeri, Walter; Ragg, Enzio

    2015-01-01

    Summary The polymerization of partially methylated β-cyclodextrin (CRYSMEB) with epichlorohydrin was carried out in the presence of a known amount of toluene as imprinting agent. Three different preparations (D1, D2 and D3) of imprinted polymers were obtained and characterized by solid-state 13C NMR spectroscopy under cross-polarization magic angle spinning (CP-MAS) conditions. The polymers were prepared by using the same synthetic conditions but with different molar ratios of imprinting agent/monomer, leading to morphologically equivalent materials but with different absorption properties. The main purpose of the work was to find a suitable spectroscopic descriptor accounting for the different imprinting process in three homogeneous polymeric networks. The polymers were characterized by studying the kinetics of the cross-polarization process. This approach is based on variable contact time CP-MAS spectra, referred to as VCP-MAS. The analysis of the VCP-MAS spectra provided two relaxation parameters: T CH (the CP time constant) and T 1ρ (the proton spin-lattice relaxation time in the rotating frame). The results and the analysis presented in the paper pointed out that T CH is sensitive to the imprinting process, showing variations related to the toluene/cyclodextrin molar ratio used for the preparation of the materials. Conversely, the observed values of T 1ρ did not show dramatic variations with the imprinting protocol, but rather confirmed that the three polymers are morphologically similar. Thus the combined use of T CH and T 1ρ can be helpful for the characterization and fine tuning of imprinted polymeric matrices. PMID:26877800

  3. Polydisperse methyl β-cyclodextrin–epichlorohydrin polymers: variable contact time 13C CP-MAS solid-state NMR characterization

    Directory of Open Access Journals (Sweden)

    Isabelle Mallard

    2015-12-01

    Full Text Available The polymerization of partially methylated β-cyclodextrin (CRYSMEB with epichlorohydrin was carried out in the presence of a known amount of toluene as imprinting agent. Three different preparations (D1, D2 and D3 of imprinted polymers were obtained and characterized by solid-state 13C NMR spectroscopy under cross-polarization magic angle spinning (CP-MAS conditions. The polymers were prepared by using the same synthetic conditions but with different molar ratios of imprinting agent/monomer, leading to morphologically equivalent materials but with different absorption properties. The main purpose of the work was to find a suitable spectroscopic descriptor accounting for the different imprinting process in three homogeneous polymeric networks. The polymers were characterized by studying the kinetics of the cross-polarization process. This approach is based on variable contact time CP-MAS spectra, referred to as VCP-MAS. The analysis of the VCP-MAS spectra provided two relaxation parameters: TCH (the CP time constant and T1ρ (the proton spin-lattice relaxation time in the rotating frame. The results and the analysis presented in the paper pointed out that TCH is sensitive to the imprinting process, showing variations related to the toluene/cyclodextrin molar ratio used for the preparation of the materials. Conversely, the observed values of T1ρ did not show dramatic variations with the imprinting protocol, but rather confirmed that the three polymers are morphologically similar. Thus the combined use of TCH and T1ρ can be helpful for the characterization and fine tuning of imprinted polymeric matrices.

  4. Time-resolved non-contact fluorescence diffuse optical tomography measurements with ultra-fast time-correlated single photon counting avalanche photodiodes

    Science.gov (United States)

    Bérubé-Lauzière, Yves; Robichaud, Vincent; Lapointe, Éric

    2007-07-01

    The design and fabrication of time-correlated single photon counting (TCSPC) avalanche photodiodes (APDs) and associated quenching circuits have made significant progresses in recent years. APDs with temporal resolutions comparable to microchannel plate photomultiplier tubes (MCP-PMTs) are now available. MCP-PMTs were until these progresses the best TCSPC detectors with timing resolutions down to 30ps. APDs can now achieve these resolutions at a fraction of the cost. Work is under way to make the manufacturing of TCSPC APDs compatible with standard electronics fabrication practices. This should allow to further reduce their cost and render them easier to integrate in complex multi-channel TCSPC electronics, as needed in diffuse optical tomography (DOT) systems. Even if their sensitive area is much smaller than that of the ubiquitous PMT used in TCSPC, we show that with appropriate selection of optical components, TCSPC APDs can be used in time-domain DOT. To support this, we present experimental data and calculations clearly demonstrating that comparable measurements can be obtained with APDs and PMTs. We are, to our knowledge, the first group using APDs in TD DOT, in particular in non-contact TD fluorescence DOT.

  5. Validation of a Torso-Mounted Accelerometer for Measures of Vertical Oscillation and Ground Contact Time During Treadmill Running.

    Science.gov (United States)

    Watari, Ricky; Hettinga, Blayne; Osis, Sean; Ferber, Reed

    2016-06-01

    The purpose of this study was to validate measures of vertical oscillation (VO) and ground contact time (GCT) derived from a commercially-available, torso-mounted accelerometer compared with single marker kinematics and kinetic ground reaction force (GRF) data. Twenty-two semi-elite runners ran on an instrumented treadmill while GRF data (1000 Hz) and three-dimensional kinematics (200 Hz) were collected for 60 s across 5 different running speeds ranging from 2.7 to 3.9 m/s. Measurement agreement was assessed by Bland-Altman plots with 95% limits of agreement and by concordance correlation coefficient (CCC). The accelerometer had excellent CCC agreement (> 0.97) with marker kinematics, but only moderate agreement, and overestimated measures between 16.27 mm to 17.56 mm compared with GRF VO measures. The GCT measures from the accelerometer had very good CCC agreement with GRF data, with less than 6 ms of mean bias at higher speeds. These results indicate a torso-mounted accelerometer provides valid and accurate measures of torso-segment VO, but both a marker placed on the torso and the accelerometer yield systematic overestimations of center of mass VO. Measures of GCT from the accelerometer are valid when compared with GRF data, particularly at faster running speeds.

  6. A Time-Frequency Respiration Tracking System using Non-Contact Bed Sensors with Harmonic Artifact Rejection

    Science.gov (United States)

    Beattie, Zachary T.; Jacobs, Peter G.; Riley, Thomas C.; Hagen, Chad C.

    2015-01-01

    Sleep apnea is a serious health condition that affects many individuals and has been associated with serious health conditions such as cardiovascular disease. Clinical diagnosis of sleep apnea requires that a patient spend the night in a sleep clinic while being wired up to numerous obtrusive sensors. We are developing a system that utilizes respiration rate and breathing amplitude inferred from non-contact bed sensors (i.e. load cells placed under bed supports) to detect sleep apnea. Multi-harmonic artifacts generated either biologically or as a result of the impulse response of the bed have made it challenging to track respiration rate and amplitude with high resolution in time. In this paper, we present an algorithm that can accurately track respiration on a second-by-second basis while removing noise harmonics. The algorithm is tested using data collected from 5 patients during overnight sleep studies. Respiration rate is compared with polysomnography estimations of respiration rate estimated by a technician following clinical standards. Results indicate that certain subjects exhibit a large harmonic component of their breathing signal that can be removed by our algorithm. When compared with technician transcribed respiration rates using polysomnography signals, we demonstrate improved accuracy of respiration rate tracking using harmonic artifact rejection (mean error: 0.18 breaths/minute) over tracking not using harmonic artifact rejection (mean error: −2.74 breaths/minute). PMID:26738176

  7. Effect of Contact Time and Gas Component on Interfacial Tension of CO2/Crude Oil System by Pendant Drop Method

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2015-01-01

    Full Text Available Pendant drop method has been used to measure the equilibrium interfacial tension and dynamic interfacial tension of CO2/crude oil system under the simulated-formation condition, in which the temperature is 355.65 K and pressure ranges from 0 MPa to 30 MPa. The test results indicated that the equilibrium interfacial tension of CO2/crude oil systems decreased with the increase of the systematic pressure. The dynamic interfacial tension of CO2/original oil, CO2/remaining oil, and CO2/produced oil systems is large at the initial contact and decreases gradually after that, and then finally it reaches dynamic balance. In addition, the higher the pressure is, the larger the magnitude of changing of CO2/crude oil interfacial tension with time will reduce. Moreover, by PVT phase experiment, gas-oil ratio, gas composition, and well fluid composition have been got, and different contents of light components in three oil samples under reservoir conditions have also been calculated. The relationship between equilibrium interfacial tensions and pressures of three different components of crude oil and CO2 system was studied, and the higher C1 is, the lower C2–C10 will be, and the equilibrium interfacial tension will get higher. Therefore, the effect of light weight fractions on interfacial tension under formation conditions was studied.

  8. Gastrointestinal pH and Transit Time Profiling in Healthy Volunteers Using the IntelliCap System Confirms Ileo-Colonic Release of ColoPulse Tablets.

    Directory of Open Access Journals (Sweden)

    Jacoba M Maurer

    Full Text Available ColoPulse tablets are an innovative development in the field of oral dosage forms characterized by a distal ileum and colon-specific release. Previous studies in humans showed release in the ileo-colonic region, but the relationship between gastrointestinal pH and release was not experimentally proven in vivo. This information will complete the in vivo release-profile of ColoPulse tablets.Release from ColoPulse tablets was studied in 16 healthy volunteers using the dual label isotope strategy. To determine gastrointestinal pH profiles and transit times the IntelliCap system was used. A ColoPulse tablet containing 13C-urea and an uncoated, immediate release tablet containing 15N2-urea were taken simultaneously followed by a standardized breakfast after three hours. Five minutes after intake of the tablets the IntelliCap capsule was swallowed and pH was measured until excretion in the feces. Breath and urine samples were collected for isotope analysis.Full analysis could be performed in 12 subjects. Median bioavailability of 13C -urea was 82% (95% CI 74-94%, range 61-114%. The median lag time (5% release of 13C was 5:42 h (95% CI 5:18-6:18 h, range 2:36-6:36 h, There was no statistically significant difference between lag time based on isotope signal and colon arrival time (CAT based on pH (median 5:42 vs 5:31 h p = 0.903. In all subjects an intestinal pH value of 7.0 was reached before release of 13C from the ColoPulse tablet occurred.From the combined data from the IntelliCap system and the 13C -isotope signal it can be concluded that release from a ColoPulse tablet in vivo is not related to transit times but occurs in the ileo-colonic region after pH 7.0 is reached. This supports our earlier findings and confirms that the ColoPulse system is a promising delivery system for targeting the distal ileum and colon.ISRCTN Registry 18301880.

  9. Large natural pH, CO2 and O2 fluctuations in a temperate tidal salt marsh on diel, seasonal, and interannual time scales

    Science.gov (United States)

    Baumann, Hannes; Wallace, Ryan; Tagliaferri, Tristen N.; Gobler, Christopher J.

    2014-01-01

    Coastal marine organisms experience dynamic pH and dissolved oxygen (DO) conditions in their natural habitats, which may impact their susceptibility to long-term anthropogenic changes. Robust characterizations of all temporal scales of natural pH and DO fluctuations in different marine habitats are needed; however, appropriate time series of pH and DO are still scarce. We used multiyear (2008–2012), high-frequency (6 min) monitoring data to quantify diel, seasonal, and interannual scales of pH and DO variability in a productive, temperate tidal salt marsh (Flax Pond, Long Island, US). pHNBS and DO showed strong and similar seasonal patterns, with average (minimum) conditions declining from 8.2 (8.1) and 12.5 (11.4) mg l−1 at the end of winter to 7.6 (7.2) and 6.3 (2.8) mg l−1 in late summer, respectively. Concomitantly, average diel fluctuations increased from 0.22 and 2.2 mg l−1 (February) to 0.74 and 6.5 mg l−1 (August), respectively. Diel patterns were modulated by tides and time of day, eliciting the most extreme minima when low tides aligned with the end of the night. Simultaneous in situ pCO2 measurements showed striking fluctuations between ∼330 and ∼1,200 (early May), ∼2,200 (mid June), and ∼4,000 μatm (end of July) within single tidal cycles. These patterns also indicate that the marsh’s strong net heterotrophy influences its adjacent estuary by ‘outwelling’ acidified and hypoxic water during ebb tides. Our analyses emphasize the coupled and fluctuating nature of pH and DO conditions in productive coastal and estuarine environments, which have yet to be adequately represented by experiments.

  10. Effect of gel firmness at cutting time, pH, and temperature on rennet coagulation and syneresis: an in situ 1H NMR relaxation study.

    Science.gov (United States)

    Hansen, Christian Lyndgaard; Rinnan, Asmund; Engelsen, Søren Balling; Janhøj, Thomas; Micklander, Elisabeth; Andersen, Ulf; van den Berg, Frans

    2010-01-13

    The objective of this study was to monitor rennet-induced milk gel formation and mechanically induced gel syneresis in situ by low-field NMR. pH, temperature, and gel firmness at cutting time were varied in a factorial design. The new curve-fitting method Doubleslicing revealed that during coagulation two proton populations with distinct transverse relaxation times (T2,1=181, T2,2=465 ms) were present in fractions (f1=98.9%, f2=1.1%). Mechanical cutting of the gel in the NMR tube induced macrosyneresis, which led to the appearance of an additional proton population (T2,3=1500-2200 ms) identified as whey. On the basis of NMR quantification of whey water the syneresis rate was calculated and found to be significantly dependent on pH and temperature.

  11. Effects of pH, hydraulic retention time and organic loading rate on biohydrogen production from the anaerobic fermentation of agri-food wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Won, S.; Lau, A. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Chemical and Biological Engineering

    2009-07-01

    This presentation reported on an experimental study in which biohydrogen was produced via anaerobic fermentation of dairy wastewater using a 6 L sequencing batch reactor. Tests were performed at ambient temperature and varying pH, hydraulic retention time (HRT) and organic loading rate (OLR). The seed sludge was not pretreated. The tests showed that methanogenic activity could be suppressed via short HRT and large OLR changes. However, the maximum hydrogen production rate was only 0.08 L/L per day without pH control. The rate of hydrogen production increased considerably when sucrose-rich synthetic wastewater was used as the substrate, and when pH was controlled. When HRT was reduced from 2.5 days to 1.25 days, observed hydrogen yield and hydrogen production rate reached 73 per cent and 4.38 L/L per day, respectively, for an optimal pH of 4.0. Volatile fatty acid was analyzed in order to determine the microbial metabolic pathway that favours increased hydrogen production. It was concluded that the co-fermentation of agri-food wastewater could improve the utilization of animal wastewater for the production of biohydrogen.

  12. Nanoparticle-electrode collision processes: Investigating the contact time required for the diffusion-controlled monolayer underpotential deposition on impacting nanoparticles

    Science.gov (United States)

    Cutress, Ian J.; Rees, Neil V.; Zhou, Yi-Ge; Compton, Richard G.

    2011-09-01

    Recent work on faradaic processes occurring during thermal nanoparticle-electrode collisions contrasts significantly from analogous research using ultrasonically-driven microparticles, where no faradaic signals were found. It is suggested that this might be explained by the differences in both particle size and contact time. To investigate this, we present results from adapted Monte Carlo random walk simulations. Using the underpotential deposition of thallium onto silver nanoparticles as a model system, it is found that an estimated minimum contact time of ca. 10-4 s is required to deposit a complete monolayer (from a 10 mM solution) onto a nanoparticle of radius 45 nm.

  13. Application of Response Surface Methodology to Study the Combined Effect of Temperature, Time and pH on Antioxidant Activity of Cherry (Prunus avium Honey

    Directory of Open Access Journals (Sweden)

    Nayik Gulzar Ahmad

    2016-12-01

    Full Text Available Response surface methodology (RSM was employed to analyze the effect of independent variables viz. temperature, time and pH on antioxidant properties of cherry honey. Seventeen runs including five replicates were used to study the combined effect of temperature (60–80°C, time (10–15 min and pH (3 to 6 on the antioxidant properties [radical scavenging activity (DPPH-RSA, total phenolic content (TPC and total flavonoid content (TFC] of cherry honey. Statistical analysis revealed that process variables significantly affected all the responses. All the three parameters viz. DPPH-RSA, TPC and TFC increased with increase in time and temperature. The antioxidant properties of cherry honey were significantly decreased with increase in pH from 3 to 6. The thermal treatment of honey at 80°C was found to be more effective than at 70 and 60°C. The results demonstrated that antioxidant activity significantly increased with formation of browning pigments.

  14. Effect of Temperature, pH, Enzyme to Substrate Ratio, Substrate Concentration and Time on the Antioxidative Activity of Hydrolysates from Goat Milk Casein by Alcalase

    Directory of Open Access Journals (Sweden)

    Shu Guowei

    2016-12-01

    Full Text Available The effect of hydrolysis temperature (45, 50, 55, 60 and 65°C, pH (7.0, 7.5, 8.0, 8.5 and 9.0, enzyme to substrate (E/S ratio (1.0, 1.5, 2.0, 2.5 and 3.0%, substrate concentration (2, 3, 4, 5 and 6% and hydrolysis time (30-240min on antioxidant peptides hydrolysated from goat’s milk casein by Alcalase was investigated using single factor experiment. In order to obtain high DPPH radical-scavenging activity, metal-chelating activity and superoxide radical scavenging activity, the optimal conditions were hydrolysis time of 150 min, temperature of 50°C, pH 8.0, E/S ratio of 2.0% and substrate concentration of 4.0%. The hydrolysis time, hydrolysis temperature, pH, E/S ratio and substrate concentration had a significant influence on degree of hydrolysis, metal-chelating activity, DPPH and superoxide radical scavenging activity on casein hydrolysate of goat milk by Alcalase, the results were beneficial for further provide theoretical basis for production of antioxidant peptides.

  15. Effects of the addition of nanoparticulate calcium carbonate on setting time, dimensional change, compressive strength, solubility and pH of MTA.

    Science.gov (United States)

    Bernardi, A; Bortoluzzi, E A; Felippe, W T; Felippe, M C S; Wan, W S; Teixeira, C S

    2017-01-01

    To evaluate nanoparticulate calcium carbonate (NPCC) using transmission electron microscopy and the effects of NPCC addition to MTA in regard to the setting time, dimensional change, compressive strength, solubility and pH. The experimental groups were G1 (MTA), G2 (MTA with 5% NPCC) and G3 (MTA with 10% NPCC). The tests followed ISO and ADA standards. The specimens in the dimensional change and compressive strength tests were measured immediately after setting, after 24 h and after 30 days. In the solubility test, rings filled with cement were weighed after setting and after 30 days. The pH was measured after 24 h and 30 days. The data were analysed with the ANOVA, Tukey's and Kruskal-Wallis tests (α = 5%). The setting time was reduced (P  G2 > G3). The solubility test revealed a difference amongst the groups when the specimens were hydrated: G2 > G1 > G3 and dehydrated: G3 > G2 > G1. The pH of the groups was similar at 24 h with higher values in each group after 30 days (P MTA accelerated the setting time, decreased compressive strength and, after 30 days, resulted in lower dimensional change (G2), higher solubility and a higher pH. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  16. Characterization of a time-resolved non-contact scanning diffuse optical imaging system exploiting fast-gated single-photon avalanche diode detection

    Energy Technology Data Exchange (ETDEWEB)

    Di Sieno, Laura, E-mail: laura.disieno@polimi.it; Dalla Mora, Alberto; Contini, Davide [Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo Da Vinci 32, 20133 Milano (Italy); Wabnitz, Heidrun; Macdonald, Rainer [Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin (Germany); Pifferi, Antonio [Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo Da Vinci 32, 20133 Milano (Italy); Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Mazurenka, Mikhail [Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin (Germany); Hannoversches Zentrum für Optische Technologien, Nienburger Str. 17, 30167 Hannover (Germany); Hoshi, Yoko [Department of Biomedical Optics, Medical Photonics Research Center, Hamamatsu University School of Medicine, Hamamatsu 431-3192 (Japan); Boso, Gianluca; Tosi, Alberto [Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Piazza Leonardo Da Vinci 32, 20133 Milano (Italy); Becker, Wolfgang [Becker and Hickl GmbH, Nahmitzer Damm 30, 12277 Berlin (Germany); Martelli, Fabrizio [Dipartimento di Fisica e Astronomia dell’Università degli Studi di Firenze, Via G. Sansone 1, Sesto Fiorentino, Firenze 50019 (Italy)

    2016-03-15

    We present a system for non-contact time-resolved diffuse reflectance imaging, based on small source-detector distance and high dynamic range measurements utilizing a fast-gated single-photon avalanche diode. The system is suitable for imaging of diffusive media without any contact with the sample and with a spatial resolution of about 1 cm at 1 cm depth. In order to objectively assess its performances, we adopted two standardized protocols developed for time-domain brain imagers. The related tests included the recording of the instrument response function of the setup and the responsivity of its detection system. Moreover, by using liquid turbid phantoms with absorbing inclusions, depth-dependent contrast and contrast-to-noise ratio as well as lateral spatial resolution were measured. To illustrate the potentialities of the novel approach, the characteristics of the non-contact system are discussed and compared to those of a fiber-based brain imager.

  17. Quantifying the combined effects of the heating time, the temperature and the recovery medium pH on the regrowth lag time of Bacillus cereus spores after a heat treatment.

    Science.gov (United States)

    Gaillard, S; Leguérinel, I; Savy, N; Mafart, P

    2005-11-15

    The purpose of this study was to quantify the lag time of re-growth of heated spores of Bacillus cereus as a function of the conditions of the heat treatment: temperature, duration and pH of the recovery medium. For a given heating temperature, curves plotting lag times versus time of heating show more or less complex patterns. However, under a heating time corresponding to a decrease of 2 decimal logarithms of the surviving populations of spores, a linear relationship between the lag time of growth and the time of the previous heat treatment can be observed. The slope of this linear relationship followed itself a Bigelow type linear relationship, the slope of which yielded a zeta-value very close to the observed conventional z-value. It was then concluded that the slope of the regrowth lag time versus the heating time followed a linear relationship with the sterilisation value reached in the course of the previous heat treatment. A sharp effect of the pH of the medium which could be described by a simple "secondary" model was observed. As expected, the observed intercept of the linear relationship between lag time and heating time (lag without previous heating) was dependent on only the pH of the medium and not on the heating temperature.

  18. (31)P-MRS of healthy human brain: ATP synthesis, metabolite concentrations, pH, and T1 relaxation times.

    Science.gov (United States)

    Ren, Jimin; Sherry, A Dean; Malloy, Craig R

    2015-11-01

    The conventional method for measuring brain ATP synthesis is (31)P saturation transfer (ST), a technique typically dependent on prolonged pre-saturation with γ-ATP. In this study, ATP synthesis rate in resting human brain is evaluated using EBIT (exchange kinetics by band inversion transfer), a technique based on slow recovery of γ-ATP magnetization in the absence of B1 field following co-inversion of PCr and ATP resonances with a short adiabatic pulse. The unidirectional rate constant for the Pi → γ-ATP reaction is 0.21 ± 0.04 s(-1) and the ATP synthesis rate is 9.9 ± 2.1 mmol min(-1)  kg(-1) in human brain (n = 12 subjects), consistent with the results by ST. Therefore, EBIT could be a useful alternative to ST in studying brain energy metabolism in normal physiology and under pathological conditions. In addition to ATP synthesis, all detectable (31)P signals are analyzed to determine the brain concentration of phosphorus metabolites, including UDPG at around 10 ppm, a previously reported resonance in liver tissues and now confirmed in human brain. Inversion recovery measurements indicate that UDPG, like its diphosphate analogue NAD, has apparent T1 shorter than that of monophosphates (Pi, PMEs, and PDEs) but longer than that of triphosphate ATP, highlighting the significance of the (31)P-(31)P dipolar mechanism in T1 relaxation of polyphosphates. Another interesting finding is the observation of approximately 40% shorter T1 for intracellular Pi relative to extracellular Pi, attributed to the modulation by the intracellular phosphoryl exchange reaction Pi ↔ γ-ATP. The sufficiently separated intra- and extracellular Pi signals also permit the distinction of pH between intra- and extracellular environments (pH 7.0 versus pH 7.4). In summary, quantitative (31)P MRS in combination with ATP synthesis, pH, and T1 relaxation measurements may offer a promising tool to detect biochemical alterations at early stages of brain dysfunctions and diseases.

  19. Start up partial nitrification at low temperature with a real-time control strategy based on blower frequency and pH.

    Science.gov (United States)

    Gu, Shengbo; Wang, Shuying; Yang, Qing; Yang, Pei; Peng, Yongzhen

    2012-05-01

    In this study, the performance of partial nitrification via nitrite at low temperature was investigated in a pilot-scale sequencing batch reactor (SBR) with a working volume of 7.0m(3). A novel real-time control strategy, based on blower frequency (BF) and pH, was designed and evaluated. The nitrogen break point (NBP) in the BF curve and the nitrate/nitrite apex point (NAP) in the pH curve were used to identify the endpoint of the aerobic and anoxic phases, respectively. The nitrite accumulation rate (NAR) rapidly increased from 19.8% to 90%. Partial nitrification was achieved at low temperature (11-16°C) in 40 days and was stably maintained for as long as 140 days by applying a real-time control strategy based on pH and BF. Fluorescence in situ hybirdization (FISH) results demonstrated that ammonia oxidation bacteria (AOB) had developed into the dominant nitrifying bacteria compared to nitrite oxidation bacteria (NOB) in the system.

  20. The influence of pH and reaction time on the formation of FeSe{sub 2} upon selenite reduction by nano-sized pyrite-greigite

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Mingliang [Sun Yat-sen Univ., Zhuhai (China). Sino-French Institute of Nuclear Engineering and Technology; Bardelli, Fabrizio; Ma, Bin; Charlet, Laurent [Grenoble Univ. (France). Environmental Geochemistry Group; Chen, Fanrong; Yang, Yongqiang [Chinese Academy of Sciences, Guangzhou (China). Key Laboratory of Mineralogy and Metallogeny; Chinese Academy of Sciences, Guangzhou (China). Guangdong Provincial Key Laboratory of Mineral Physics and Materials

    2016-11-01

    The influence of pH and reaction time on the formation of FeSe{sub 2} by reductive precipitation of Se(IV) with nano-sized pyrite-greigite was investigated. Reductive precipitation is an effective method of attenuating the mobility of {sup 79}Se, which is foreseen to be a dangerous radioisotope for the geological disposal of high-level radioactive waste (HLW). The results indicated that Se(0)was formed at pH <4.05, whereas, at pH > 6.07, considerable amount of FeSe{sub 2} was formed along with Se(0). These observations are in agreement with the thermodynamic predictions reported in this work. Furthermore, the formation of FeSe{sub 2} was found to continue by increasing the reaction time, indicating that the Se(0) formed in the early reaction stage is gradually transformed to FeSe{sub 2} upon the depletion of aqueous Se(IV). Since FeSe{sub 2} has a stronger reactivity than pyrite, it was proposed that greigite, rather than pyrite, was responsible for the formation of FeSe{sub 2}. The findings in this study are of interest for key geochemical processes governing the mobility of toxic {sup 79}Se in the environment in presence of iron sulfides.

  1. Attributes for MRB_E2RF1 Catchments in Selected Major River Basins of the Conterminous United States: Contact Time, 2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This tabular data set represents the average contact time, in units of days, compiled for every MRB_E2RF1 catchment of Major River Basins (MRBs, Crawford and others,...

  2. A surface-micromachining-based inertial micro-switch with compliant cantilever beam as movable electrode for enduring high shock and prolonging contact time

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Qiu [National Key Laboratory of Science and Technology on Micro/Nano Fabrication, School of Electronics Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 (China); Yang, Zhuoqing, E-mail: yzhuoqing@sjtu.edu.cn [National Key Laboratory of Science and Technology on Micro/Nano Fabrication, School of Electronics Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 (China); Fu, Bo; Li, Jianhua; Wu, Hao [Huaihai Industrial Group Co., Ltd., Changzhi, Shanxi Province, 046012 (China); Zhang, Qihuan; Sun, Yunna; Ding, Guifu; Zhao, Xiaolin [National Key Laboratory of Science and Technology on Micro/Nano Fabrication, School of Electronics Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 (China)

    2016-11-30

    Highlights: • The designed cantilever beam attached to the proof mass can endure a larger shock acceleration (∼1000 g order of magnitude) compared to those traditional designs (∼100 g order of magnitude). • Effect of the pulse width on the threshold acceleration, the response time and the contact time is investigated. • A constraint sleeve structure is introduced to lower the off-axis sensitivity. - Abstract: A novel laterally-driven inertial micro-switch with two L-shaped elastic cantilever beams as the movable electrode, which is attached to the proof mass, is proposed in this paper. The advantage of this design is that the contact time of the inertial micro-switch can be prolonged. Meanwhile, the micro-switch can withstand a higher shock than the traditional designs whose cantilever beams are attached to the fixed electrode. The designed inertial micro-switch was simulated and optimized with ANSYS software and fabricated on a quartz substrate by surface micromachining technology. The simulated result demonstrates that the threshold acceleration (a{sub ths}) under stable switch-on state is about 288 g and the contact time is about 198 μs when the pulse width of acceleration loads is 1 ms. At the same time, it indicates that the threshold acceleration, the response time and the contact time of designed micro-switch all increase with the pulse width of acceleration loads. The simulation of impact process in non-sensitive direction shows that the introduced constraint sleeve structure in the novel inertial micro-switch can lower the off-axis sensitivity. The fabricated micro-switch prototype has been tested by a standard dropping hammer system under shock accelerations with various amplitudes and pulse widths. The experimental measurements show that the contact time is about 150 μs when the threshold acceleration is about 288 g. It also indicates that the response time and the contact time both increase with the pulse width, which is consistent with the

  3. DBP formation in hot and cold water across a simulated distribution system: effect of incubation time, heating time, pH, chlorine dose, and incubation temperature.

    Science.gov (United States)

    Liu, Boning; Reckhow, David A

    2013-10-15

    This paper demonstrates that disinfection byproducts (DBP) concentration profiles in heated water were quite different from the DBP concentrations in the cold tap water. Chloroform concentrations in the heated water remained constant or even decreased slightly with increasing distribution system water age. The amount of dichloroacetic acid (DCAA) was much higher in the heated water than in the cold water; however, the maximum levels in heated water with different distribution system water ages did not differ substantially. The levels of trichloroacetic acid (TCAA) in the heated water were similar to the TCAA levels in the tap water, and a slight reduction was observed after the tap water was heated for 24 h. Regardless of water age, significant reductions of nonregulated DBPs were observed after the tap water was heated for 24 h. For tap water with lower water ages, there were significant increases in dichloroacetonitrile (DCAN), chloropicrin (CP), and 1,1-dichloropropane (1,1-DCP) after a short period of heating. Heating of the tap water with low pH led to a more significant increase of chloroform and a more significant short-term increase of DCAN. High pH accelerated the loss of the nonregulated DBPs in the heated water. The results indicated that as the chlorine doses increased, levels of chloroform and DCAA in the heated water increased significantly. However, for TCAA, the thermally induced increase in concentration was only notable for the chlorinated water with very high chlorine dose. Finally, heating may lead to higher DBP concentrations in chlorinated water with lower distribution system temperatures.

  4. Eberhard Widmann (Stefan Meyer Institute, Vienna) and Silke Federmann (Ph.D. Student from Vienna in the CERN-Austrian Ph.D. program) together with a microwave cavity developed by Silke at CERN. The cavity will be used for the first time to look for spin-flip transitions of antihydrogen atoms later this year.

    CERN Multimedia

    Maximilien Brice

    2011-01-01

    Eberhard Widmann (Stefan Meyer Institute, Vienna) and Silke Federmann (Ph.D. Student from Vienna in the CERN-Austrian Ph.D. program) together with a microwave cavity developed by Silke at CERN. The cavity will be used for the first time to look for spin-flip transitions of antihydrogen atoms later this year.

  5. Time/space pattern contacting contaminated water in specific rural areas%乡村居民疫水接触时空规律研究

    Institute of Scientific and Technical Information of China (English)

    袁宜; 赵安

    2014-01-01

    基于农村居民疫水接触的空间行为及作息时间的地理调查,了解乡村居民的血吸虫病疫水接触时空规律,对43个行政村的疫水接触人数、方式、天数、接触季节和时间段进行调查。农村居民疫水接触方式有种田、捕鱼、游泳、抗洪、挖沙、打藜蒿、放牛、养鸭和洗衣服洗菜一共9种方式,接触方式多、时间长,感染血吸虫病危险性较大。%Survey of spatial behavior and routine schedule in some rural residences is carried to obtain the time and space patter how the rural people contact the contaminated water .A questionnaire is conducted in 43 administrative villages ,which includes the number of people ,contacting way ,days , seasons and daytime section .The result show that there are 9 contacting ways including farming , fishing ,swimming ,fighting flood ,dredging ,picking quinoa artemisia ,cattling ,duck breeding and washing .The more the contacting way and time are ,the more the risk to get the schistosomiasis .

  6. Transformation of deoxynivalenol and its acetylated derivatives in Chinese steamed bread making, as affected by pH, yeast, and steaming time.

    Science.gov (United States)

    Wu, Li; Wang, Bujun

    2016-07-01

    We hereby report the transformation of deoxynivalenol (DON) and its acetylated derivatives (3-ADON and 15-ADON) by spiking targeted mycotoxins to Fusarium mycotoxin-free flour in the process of making Chinese steamed bread (CSB). The impacts of pH, yeast level, and steaming time on the transformation of 3-ADON to DON were investigated. DON, 3-ADON, and 15-ADON were analyzed by UPLC-MS/MS. Spiked DON was stable throughout the CSB making process. Spiked 3-ADON and 15-ADON were partially deacetylated and transformed to DON during kneading (54.1-60.0% and 59.3-77.5%, respectively), fermentation (64.0-76.9% and 78.2-91.6%, respectively), and steaming (47.2-52.7% and 52.4-61.9%, respectively). The ADONs level increased after steaming compared with their level in the previous step. The pH level and steaming duration significantly (Pprocess. Briefly, alkaline conditions and short steaming times favored the deacetylation of 3-ADON. The level of yeast did not remarkably (Ptransformation between ADONs and DON.

  7. Nutrient leaching, soil pH and changes in microbial community increase with time in lead-contaminated boreal forest soil at a shooting range area.

    Science.gov (United States)

    Selonen, Salla; Setälä, Heikki

    2017-02-01

    Despite the known toxicity of lead (Pb), Pb pellets are widely used at shotgun shooting ranges over the world. However, the impacts of Pb on soil nutrients and soil microbes, playing a crucial role in nutrient cycling, are poorly understood. Furthermore, it is unknown whether these impacts change with time after the cessation of shooting. To shed light on these issues, three study sites in the same coniferous forest in a shooting range area were studied: an uncontaminated control site and an active and an abandoned shooting range, both sharing a similar Pb pellet load in the soil, but the latter with a 20-year longer contamination history. Soil pH and nitrate concentration increased, whilst soil phosphate concentration and fungal phospholipid fatty acid (PLFA) decreased due to Pb contamination. Our results imply that shooting-derived Pb can influence soil nutrients and microbes not only directly but also indirectly by increasing soil pH. However, these mechanisms cannot be differentiated here. Many of the Pb-induced changes were most pronounced at the abandoned range, and nutrient leaching was increased only at that site. These results suggest that Pb disturbs the structure and functions of the soil system and impairs a crucial ecosystem service, the ability to retain nutrients. Furthermore, the risks of shooting-derived Pb to the environment increase with time.

  8. Probing the General Time Scale Question of Boronic Acid Binding with Sugars in Aqueous Solution at Physiological pH

    Science.gov (United States)

    Ni, Nanting; Laughlin, Sarah; Wang, Yingji; Feng, You; Zheng, Yujun

    2012-01-01

    The boronic acid group is widely used in chemosensor design due to its ability to reversibly bind diol-containing compounds. The thermodynamic properties of the boronic acid-diol binding process have been investigated extensively. However, there are few studies of the kinetic properties of such binding processes. In this report, stopped-flow method was used for the first time to study the kinetic properties of the binding between three model arylboronic acids, 4-, 5-, and 8-isoquinolinylboronic acids, and various sugars. With all the boronic acid-diol pair sexamined, reactions were complete within seconds. The kon values with various sugars follow the order of D-fructose >D-tagatose>D-mannose >D-glucose. This trend tracks the thermodynamic binding affinities for these sugars and demonstrates that the “on” rate is the key factor determining the binding constant. PMID:22464680

  9. Influence of ammonium sulphate feeding time on fed-batch Arthrospira (Spirulina) platensis cultivation and biomass composition with and without pH control.

    Science.gov (United States)

    Rodrigues, Mayla Santos; Ferreira, Lívia Seno; Converti, Attilio; Sato, Sunao; de Carvalho, João Carlos Monteiro

    2011-06-01

    Previous work demonstrated that a mixture of NH(4)Cl and KNO(3) as nitrogen source was beneficial to fed-batch Arthrospira (Spirulina) platensis cultivation, in terms of either lower costs or higher cell concentration. On the basis of those results, this study focused on the use of a cheaper nitrogen source mixture, namely (NH(4))(2)SO(4) plus NaNO(3), varying the ammonium feeding time (T=7-15 days), either controlling the pH by CO(2) addition or not. A. platensis was cultivated in mini-tanks at 30°C, 156 μmol photons m(-2) s(-1), and starting cell concentration of 400 mg L(-1), on a modified Schlösser medium. T=13 days under pH control were selected as optimum conditions, ensuring the best results in terms of biomass production (maximum cell concentration of 2911 mg L(-1), cell productivity of 179 mg L(-1)d(-1) and specific growth rate of 0.77 d(-1)) and satisfactory protein and lipid contents (around 30% each).

  10. Comparison of probabilistic and deterministic predictions of time to growth of Listeria monocytogenes as affected by pH and temperature in food.

    Science.gov (United States)

    Guevara, Leymaya; Martínez, Antonio; Fernández, Pablo S; Muñoz-Cuevas, Marina

    2011-01-01

    Stochastic models are useful for estimating the risk of foodborne illness and they can be integrated, besides other sources of variability, into microbial risk assessment. A stochastic approach to evaluate growth of two strains of Listeria monocytogenes influenced by different factors affecting microbial growth (pH and storage temperature) was performed. An individual-based approach of growth through optical density measurements was used. From results obtained, histograms of the lag phase were generated and distributions were fitted. Histograms presented increased variation when the factors applied were suboptimal for L. monocytogenes and they were combined. The extreme value distribution was ranked as the best one in most cases, whereas normal was the poorest fitting distribution. To evaluate the influence of pH and storage temperature on L. monocytogenes CECT 5672 in real food, commercial samples of courgette and carrot soup were inoculated with this pathogen. It was able to grow in both soups at storage temperatures from 4°C to 20°C. Using the distributions adjusted, predictions of time to growth (10² cfu/g) of L. monocytogenes were established by Monte Carlo simulation and they were compared with deterministic predictions and observations in foods.

  11. Probabilistic model for the spoilage wine yeast Dekkera bruxellensis as a function of pH, ethanol and free SO2 using time as a dummy variable.

    Science.gov (United States)

    Sturm, M E; Arroyo-López, F N; Garrido-Fernández, A; Querol, A; Mercado, L A; Ramirez, M L; Combina, M

    2014-01-17

    The present study uses a probabilistic model to determine the growth/no growth interfaces of the spoilage wine yeast Dekkera bruxellensis CH29 as a function of ethanol (10-15%, v/v), pH (3.4-4.0) and free SO2 (0-50 mg/l) using time (7, 14, 21 and 30 days) as a dummy variable. The model, built with a total of 756 growth/no growth data obtained in a simile wine medium, could have application in the winery industry to determine the wine conditions needed to inhibit the growth of this species. Thereby, at 12.5% of ethanol and pH 3.7 for a growth probability of 0.01, it is necessary to add 30 mg/l of free SO2 to inhibit yeast growth for 7 days. However, the concentration of free SO2 should be raised to 48 mg/l to achieve a probability of no growth of 0.99 for 30 days under the same wine conditions. Other combinations of environmental variables can also be determined using the mathematical model depending on the needs of the industry. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. PENENTUAN WAKTU KONTAK DAN pH OPTIMUM PENYERAPAN METILEN BIRU MENGGUNAKAN ABU SEKAM PADI

    Directory of Open Access Journals (Sweden)

    Anung Riapanitra

    2006-11-01

    Full Text Available Dyes are widely used for colouring in textile industries, significant losses occur during the manufacture and processing of the product, and these lost chemical are discharged in surrounding effluent. Adsorption of dyes is an effective technology for treatment of wastewater contaminated by the mismanaged of different types of dyes. In this research, we investigated the potential of rice husk ash for removal of methylene blue dyeing agent in aqueous system. The aim of this research is to find out the optimum contact time and pH on the adsorption of methylene blue using rice husk ash. Batch kinetics studies were carried out under varying experimental condition of contact time and pH. An adsorption equilibrium condition was reached within 10 minutes and the optimum condition for adsorption was at pH 3. The adsorption of methylene blue was decreasing with decreasing the solution pH value.

  13. A multi-view time-domain non-contact diffuse optical tomography scanner with dual wavelength detection for intrinsic and fluorescence small animal imaging.

    Science.gov (United States)

    Lapointe, Eric; Pichette, Julien; Bérubé-Lauzière, Yves

    2012-06-01

    We present a non-contact diffuse optical tomography (DOT) scanner with multi-view detection (over 360°) for localizing fluorescent markers in scattering and absorbing media, in particular small animals. It relies on time-domain detection after short pulse laser excitation. Ultrafast time-correlated single photon counting and photomultiplier tubes are used for time-domain measurements. For light collection, seven free-space optics non-contact dual wavelength detection channels comprising 14 detectors overall are placed around the subject, allowing the measurement of time point-spread functions at both excitation and fluorescence wavelengths. The scanner is endowed with a stereo camera pair for measuring the outer shape of the subject in 3D. Surface and DOT measurements are acquired simultaneously with the same laser beam. The hardware and software architecture of the scanner are discussed. Phantoms are used to validate the instrument. Results on the localization of fluorescent point-like inclusions immersed in a scattering and absorbing object are presented. The localization algorithm relies on distance ranging based on the measurement of early photons arrival times at different positions around the subject. This requires exquisite timing accuracy from the scanner. Further exploiting this capability, we show results on the effect of a scattering hetereogenity on the arrival time of early photons. These results demonstrate that our scanner provides all that is necessary for reconstructing images of small animals using full tomographic reconstruction algorithms, which will be the next step. Through its free-space optics design and the short pulse laser used, our scanner shows unprecedented timing resolution compared to other multi-view time-domain scanners.

  14. Assessing the acidity and total sugar content of four different commercially available beverages commonly consumed by children and its time-dependent effect on plaque and salivary pH

    Directory of Open Access Journals (Sweden)

    Abhishek Jha

    2015-01-01

    Full Text Available Introduction: Sugared beverages such as cola, packaged juice, are known for cariogenicity their intake leads to the immediate drop in plaque and salivary pH, which can be an etiologic factor for dental caries. Objective: The objective was to assess the endogenous acidity and total sugar content of four commercially available beverages commonly consumed by children in India and its effect on salivary and plaque pH. Materials and Methods: A crossover controlled trial was conducted. 60 randomly selected school children from school at south Bangalore, who were meeting the inclusion criteria, were asked to refrain from oral hygiene practices for 24 h till the sample collection. Children were divided into four groups and for each group test drink was given. Plaque and salivary sample were collected at the time of 2, 5, 10, 20, and 30 min and were sent for pH estimation. 7 days of washout time was given for each cross-over and 3 such cross-over was done during the study and the drinks were interchanged. Results: Sweet lassi was found to be having maximum total sugar content of and Coca-Cola had the lowest pH 5.3. Milk showed least sugar content and highest pH (6.7. Study showed a significant drop in pH after consumption of all the test drinks (P = 0. 05. Carbonated beverage, that is, Coca-Cola Showed the maximum drop of pH, followed by Pulpy orange in both the plaque as well as saliva. Coca-Cola showed the drop of plaque pH below the critical level, 5.44 (0.134. Conclusion: Sweet lassi showed the maximum inherent total sugar content, lowest inherent pH and maximum fall in plaque and salivary pH, was found with Coca-Cola.

  15. Plant Habitat (PH)

    Science.gov (United States)

    Onate, Bryan

    2016-01-01

    The International Space Station (ISS) will soon have a platform for conducting fundamental research of Large Plants. Plant Habitat (PH) is designed to be a fully controllable environment for high-quality plant physiological research. PH will control light quality, level, and timing, temperature, CO2, relative humidity, and irrigation, while scrubbing ethylene. Additional capabilities include leaf temperature and root zone moisture and oxygen sensing. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs. There will be several internal cameras (visible and IR) to monitor and record plant growth and operations.

  16. Introduction of a new model for time-continuous and non-contact investigations of in-vitro thrombolysis under physiological flow conditions

    Directory of Open Access Journals (Sweden)

    Trillenberg Peter

    2011-05-01

    Full Text Available Abstract Background Thrombolysis is a dynamic and time-dependent process influenced by the haemodynamic conditions. Currently there is no model that allows for time-continuous, non-contact measurements under physiological flow conditions. The aim of this work was to introduce such a model. Methods The model is based on a computer-controlled pump providing variable constant or pulsatile flows in a tube system filled with blood substitute. Clots can be fixed in a custom-built clot carrier within the tube system. The pressure decline at the clot carrier is measured as a novel way to measure lysis of the clot. With different experiments the hydrodynamic properties and reliability of the model were analyzed. Finally, the lysis rate of clots generated from human platelet rich plasma (PRP was measured during a one hour combined application of diagnostic ultrasound (2 MHz, 0.179 W/cm2 and a thrombolytic agent (rt-PA as it is commonly used for clinical sonothrombolysis treatments. Results All hydrodynamic parameters can be adjusted and measured with high accuracy. First experiments with sonothrombolysis demonstrated the feasibility of the model despite low lysis rates. Conclusions The model allows to adjust accurately all hydrodynamic parameters affecting thrombolysis under physiological flow conditions and for non-contact, time-continuous measurements. Low lysis rates of first sonothrombolysis experiments are primarily attributable to the high stability of the used PRP-clots.

  17. A moving boundary solution for solidification of lava lake and magma intrusion in the presence of time-varying contact temperature

    Indian Academy of Sciences (India)

    Ajay Manglik

    2005-04-01

    During the solidification of a lava lake heat is released convectively from the top surface as well as conductively into the country rock from the base, leading to non-uniform solidification. The upper solidified layer grows at a faster rate than the lower solidified layer. Similarly, solidification of magma intrusion within the crust is also non-uniform due to the presence of thermal gradient in the crust. Available analytical solution for solidification of a melt layer assumes only symmetric cooling about the centre of the layer. In the present work a moving boundary solution for thermal evolution and non-uniform solidification of a melt layer incorporating time-varying contact temperature conditions at both of its boundaries is developed. The solution is obtained by using the Fourier spectral approach in the space domain and a modified finite difference scheme in the time domain, and is validated with available analytical solutions for simple cases and a semi-analytical solution for the case involving temperature gradient in the country rock. This solution can be used to analyse solidification of lava lakes and magma intrusions experiencing time-dependent temperature variation at their contacts with the country rock.

  18. Relationship of breast fillet deboning time to shear force, pH, cooking loss and color in broilers stunned by high electrical current

    Directory of Open Access Journals (Sweden)

    P. PAPINAHO

    2008-12-01

    Full Text Available Experiments were conducted to determine the relationships between deboning time and broiler breast meat quality, as determined by objective meat tenderness, pH, color and cooking loss. All birds were processed in a European commercial processing plant using a high current, constant voltage stunning system and air chilling. According to a modified Mitscherlich response equation, p11 values reached their ultimate value by 5.77 h post-mortem, with an asymptotic 95 % confidence interval of 5.72 h-5.81 h post-mortem. The shear force data, which were analyzed using a logistic model, suggested that broiler breast fillets should be aged intact on the carcass for 10.58 h, 5.94 h or 2.28 h to guarantee that over 95 % of the fillets reach Allo-Kramer shear forces of 8.0, 9.0 or 11.0 kg/g, respectively. Since acceptable meat tenderness values vary with country, geographical area, or consumer groups, acceptable ranges should be determined according to potential market demands. No relationships between deboning time and fresh meat color or cooking loss was found.;

  19. Malairajan Singanan", M.Sc.,Ph.D, Singanan Vinodhini“, M.Sc

    African Journals Online (AJOL)

    Removal of Cadmium from Industrial Wastewater Malairajan Set al 59. ORIGIV,4 L 4 RTICLE ... contact time, effect of adsorbent dose, control of pH and temperature. Cadmium ion – ... metąls arrive in soil from atmospheric deposition, although ...

  20. Influence of pH on wetting kinetics of a pine forest soil

    Science.gov (United States)

    Amer, Ahmad; Schaumann, Gabriele; Diehl, Dörte

    2014-05-01

    Water repellent properties of organic matter significantly alter soil water dynamics. Various environmental factors control appearance and breakup of repellency in soil. Beside water content and temperature also pH exerts an influence on soil water repellency although investigations achieved partly ambiguous results; some found increasing repellency with increasing pH (Terashima et al. 2004; Duval et al. 2005), other with decreasing pH (Karnok et al. 1993; Roper 2005) and some found repellency maxima at intermediate pH and an increase with decreasing and with increasing pH (Bayer and Schaumann 2007; Diehl et al. 2010). The breakup of repellency may be observed via the time dependent sessile drop contact angle (TISED). With water contact time, soil-water contact angle decreases until complete wetting is reached. Diehl and Schaumann (2007) calculated the activation energy of the wetting process from the rate of sessile drop wetting obtained at different temperatures and draw conclusions on chemical or physical nature of repellency. The present study aims at the influence of pH on the wetting kinetics of soil. Therefore, TISED of soil was determined as a function of pH and temperature. We used upper soil samples (0 - 10 cm) from a pine forest in the southwest of Germany (Rheinland-Pfalz). Samples were air-dried, sieved Contact Angle Meter (Dataphysics, Germany) on three replications for each soil sample. Apparent work of adhesion was calculated, plotted vs. time and mathematically fitted using double exponential function. Rate constants of wetting were used to determine the activation energy by Arrhenius equation. First results indicated that despite comparable initial contact angles, pH alteration strongly changed the wetting rate suggesting maximum wetting resistance at the natural pH of 4.3 and decreasing wetting resistance at lower and at higher pH. The poster will present further current results of the ongoing study and discuss the activation energy of the

  1. Numerical analysis of a coupled problem: Time evolution of a tokamak plasma in contact with a conducting wall

    Energy Technology Data Exchange (ETDEWEB)

    Albanese, R.; Formisano, A.; Fresa, R.; Martone, R.; Rubinacci, G.; Villone, F. [Univ. degli Studi di Napoli Federico II (Italy). Dipt. di Ingegneria Elettrica

    1996-05-01

    In this paper the authors analyze the time evolution of a tokamak plasma after the failure of the vertical control system. In this case, the plasma eventually touches the conducting wall and gives rise to currents which flow partly in the wall, partly in the plasma. They show how, under simplifying assumptions, the problem can be analyzed by means of pure electromagnetic formulations. After a brief review of the state of the art in the analysis of this phenomenon, they propose and discuss three alternative Eulerian approaches: an evolutionary equilibrium formulation, a convection-diffusion model and a 3D error-based approach.

  2. Synthesis of Nanocrystalline SnOx (x = 1–2 Thin Film Using a Chemical Bath Deposition Method with Improved Deposition Time, Temperature and pH

    Directory of Open Access Journals (Sweden)

    Zulkarnain Zainal

    2011-09-01

    Full Text Available Nanocrystalline SnOx (x = 1–2 thin films were prepared on glass substrates by a simple chemical bath deposition method. Triethanolamine was used as complexing agent to decrease time and temperature of deposition and shift the pH of the solution to the noncorrosive region. The films were characterized for composition, surface morphology, structure and optical properties. X-ray diffraction analysis confirms that SnOx thin films consist of a polycrystalline structure with an average grain size of 36 nm. Atomic force microscopy studies show a uniform grain distribution without pinholes. The elemental composition was evaluated by energy dispersive X-ray spectroscopy. The average O/Sn atomic percentage ratio is 1.72. Band gap energy and optical transition were determined from optical absorbance data. The film was found to exhibit direct and indirect transitions in the visible spectrum with band gap values of about 3.9 and 3.7 eV, respectively. The optical transmittance in the visible region is 82%. The SnOx nanocrystals exhibit an ultraviolet emission band centered at 392 nm in the vicinity of the band edge, which is attributed to the well-known exciton transition in SnOx. Photosensitivity was detected in the positive region under illumination with white light.

  3. INFLUENCE OF “ANTE-MORTEM” RESTING TIME AND MOLASSES DIET UPON pH LEVELS OF EQUINES MEAT (Equus caballus INFLUÊNCIA DO TEMPO DE DESCANÇO "ANTE-MORTEM" E DIETA DE MELAÇO NOS ÍNDICES DE pH DA CARNE DE EQÜINOS (Equus caballus

    Directory of Open Access Journals (Sweden)

    César Augusto Garcia

    2007-09-01

    Full Text Available

    Influence of “ante-mortem” resting time and molasses diet upon pH levels of equines meat (Equus caballus were studied. It was measured the pH of triceps brachial and biceps femoral muscles in twenty four adults and hybrids equines with approximately  the same weights. The animals were divided, before death, in six groups with ";ante-mortem"; resting time of zero, six, fourteen, eighteen and twenty-four hours, respectively. The animals groups with eighteen hours of rest were divided in two sub-groups and one received water solution with 5% of molasses. The pH was measured using pH meter micronal with zero, six, twelve, eighteen, twenty-four and thirty hours after death. The group with smaller pH levels was the group with twenty-four hours of “ante-mortem” resting. Differences in pH levels were not observed between the group fed with water solution with 5% of molasses and the group not fed, but with the same time of rest.

    Foram mensuradas as concentrações de pH de 24 eqüinos adultos, machos e de pesos aproximadamente iguais. Dividiu-se os animais em 5 lotes com 4 animais cada um, com exceção do lote no 4 que foi subdividido em sublote 4A e sublote 4B com 4 animais cada um deles. Todos os animais receberam jejum e dieta hídrica, com exceção do lote no 4B que recebeu solução aquosa a 5% de melaço, para observar se influiria nas concentrações de pH. Cada lote foi submetido a um tempo de descanso ante-mortem diferente, sendo zero hora de descanso para o lote no 1, seis horas de descanso para o lote no 2, quatorze, dezoito e vinte e quatro horas de descanso ante mortem para os lotes No 3, 4A, 4B e 5, respectivamente. Os menores valores de pH foram observados no lote que descansou por 24 horas. Não foram observadas diferenças nos valores de pH entre o lote de animais que recebeu dieta de melaço e

  4. Measuring The Contact Resistances Of Photovoltaic Cells

    Science.gov (United States)

    Burger, D. R.

    1985-01-01

    Simple method devised to measure contact resistances of photovoltaic solar cells. Method uses readily available equipment and applicable at any time during life of cell. Enables evaluation of cell contact resistance, contact-end resistance, contact resistivity, sheet resistivity, and sheet resistivity under contact.

  5. QGIS TimeManager and how the QGIS community helped me make a great leap forward in visualizing tracking data for my PhD project

    DEFF Research Database (Denmark)

    Nielsen, Søren Zebitz

    2015-01-01

    This blog post is the story how collaboration with the QGIS developer community made me able to produce some much needed visualizations of pedestrian tracking data for my ongoing PhD project.......This blog post is the story how collaboration with the QGIS developer community made me able to produce some much needed visualizations of pedestrian tracking data for my ongoing PhD project....

  6. Ice nucleation properties of mineral dust particles: determination of onset RHi, IN active fraction, nucleation time-lag, and the effect of active sites on contact angles

    Directory of Open Access Journals (Sweden)

    S. Dobbie

    2010-01-01

    Full Text Available A newly developed ice nucleation experimental set up was used to investigate the heterogeneous ice nucleation properties of three Saharan and one Spanish dust particle samples. It was observed that the spread in the onset relative humidities with respect to ice (RHi for Saharan dust particles varied from 104% to 110%, whereas for the Spanish dust from 106% to 110%. The elemental composition analysis shows a prominent Ca feature in the Spanish dust sample which could potentially explain the differences in nucleation threshold. Although the spread in the onset RHi for the three Saharan dust samples were in agreement, the active fractions and nucleation time-lags calculated at various temperature and RHi conditions were found to differ. This could be due to the subtle variation in the elemental composition of the dust samples, and surface irregularities like steps, cracks, cavities etc. A combination of classical nucleation theory and active site theory is used to understand the importance of these surface irregularities on the nucleability parameter, contact angle that is widely used in ice cloud modeling. These calculations show that the surface irregularities can reduce the contact angle by approximately 10 degrees.

  7. Elastic recoil detection using time-of-flight for analysis of TiN/AlSiCu/TiN/Ti contact metallization structures

    Science.gov (United States)

    Gujrathi, S. C.; Gagnon, G.; Fortin, V.; Caron, M.; Currie, J. F.; Ouellet, L.; Tremblay, Y.

    1998-03-01

    The ability of elastic recoil detection (ERD) with time-of-flight (TOF) to quantify multilayer TiN/AlSiCu/TiN/Ti contact metallization structures on Si and SiO 2 has been demonstrated. In the technique a single microchannel plate (MCP) detector assembly and a silicon surface barrier detector (SSBD) were used. Technically high quality multilayer structures that have important applications in VLSI/ULSI devices were produced in a commercial Varian M2000 cluster tool by sputtering techniques. Several device process parameters such as annealing temperature (450°C, 500°C and 550°C), TiN oxidation, TiN ARC layer, TiN diffusion barrier thickness (50 and 90 nm) and types of substrate (Si and SiO 2) have important consequences on the performance of the product. The effect of changes in the above mentioned parameters on the elemental composition have been reliably studied by ERD. All the elements from H to Cu including substrate Si of a contact structure have been quantitatively and simultaneously profiled in a single experiment. The reproducibility of the major concentrations (N, O, Al, Si and Ti) in a multilayer test sample in every batch was within ±5%. Grazing angle X-ray diffraction (XRD) and the analyses of the ternary and quaternary phase diagrams complemented by the ERD investigations have been used to identify various phases in the layers. These results were then correlated with the measured electrical properties.

  8. Ultra-fast time-correlated single photon counting avalanche photodiodes for time-domain non-contact fluorescence diffuse optical tomography

    Science.gov (United States)

    Robichaud, Vincent; Lapointe, Éric; Bérubé-Lauzière, Yves

    2007-06-01

    Recent advances in the design and fabrication of avalanche photodiodes (APDs) and quenching circuits for timecorrelated single photon counting (TCSPC) have made available detectors with timing resolutions comparable to microchannel plate photomultiplier tubes (MCP-PMTs). The latter, were until recently the best TCSPC detectors in terms of temporal resolution (standard electronics fabrication processes in a near future. This will contribute to further decrease their price and ease their integration in complex multi-channel detection systems, as required in diuse optical imaging (DOI) and tomography (DOT). We present, to our knowledge for the first time, results which demonstrate that, despite their small sensitive area, TCSPC APDs can be used in time-domain (TD) DOT and more generally in TD DOI. With appropriate optical design of the detection channel, our experiments show that it is possible to obtain comparable measurements with APDs as with PMTs.

  9. Potential method for gas production: high temperature co-pyrolysis of lignite and sewage sludge with vacuum reactor and long contact time.

    Science.gov (United States)

    Yang, Xiao; Yuan, Chengyong; Xu, Jiao; Zhang, Weijiang

    2015-03-01

    Lignite and sewage sludge were co-pyrolyzed in a vacuum reactor with high temperature (900°C) and long contact time (more than 2h). Beneficial synergetic effect on gas yield was clearly observed. Gas yield of blend fuel was evidently higher than that of both parent fuels. The gas volume yield, gas lower heating value (LHV), fixed carbon conversion and H2/CO ratio were 1.42 Nm(3)/kg(blend fuel), 10.57 MJ/Nm(3), 96.64% and 0.88% respectively, which indicated this new method a feasible one for gas production. It was possible that sewage sludge acted as gasification agents (CO2 and H2O) and catalyst (alkali and alkaline earth metals) provider during co-pyrolysis, promoting CO2-char and H2O-char gasification which, as a result, invited the improvement of gas volume yield, gas lower heating value and fixed carbon conversion.

  10. Colour Evaluation, Bioactive Compound Content, Phenolic Acid Profiles and in Vitro Biological Activity of Passerina del Frusinate White Wines: Influence of Pre-Fermentative Skin Contact Times.

    Science.gov (United States)

    Carbone, Katya; Fiordiponti, Luciano

    2016-07-22

    Passerina del Frusinate is an autochthonous wine grape variety, which grows in the Lazio region that is currently being evaluated by local wine producers. In this study, colour properties (CIELab coordinates), bioactive compounds (total polyphenols and flavan-3-ols), HPLC-DAD phenolic acid profiles and in vitro biological activity of monovarietal Passerina del Frusinate white wines and the effect of different maceration times (0, 18 and 24 h) were evaluated based on these parameters. Results highlighted statistically significant differences for almost all analysed parameters due to a strong influence of the pre-fermentative skin contact time. The flavan content of macerated wines was six times higher than that of the control, while total polyphenols were 1.5 times higher. According to their phytochemical content, macerated wines showed the highest antiradical capacity tested by means of DPPH(•) and ABTS(+•) assays. Besides, prolonged maceration resulted in a reduction of CIELab coordinates as well as of the content of phenolic substances and antiradical capacity. Among the phenolic acids analysed, the most abundant were vanillic acid and caffeic acid; the latter proved to be the most susceptible to degradation as a result of prolonged maceration. Passerina del Frusinate appears as a phenol-rich white wine with a strong antioxidant potential similar to that of red wines.

  11. Colour Evaluation, Bioactive Compound Content, Phenolic Acid Profiles and in Vitro Biological Activity of Passerina del Frusinate White Wines: Influence of Pre-Fermentative Skin Contact Times

    Directory of Open Access Journals (Sweden)

    Katya Carbone

    2016-07-01

    Full Text Available Passerina del Frusinate is an autochthonous wine grape variety, which grows in the Lazio region that is currently being evaluated by local wine producers. In this study, colour properties (CIELab coordinates, bioactive compounds (total polyphenols and flavan-3-ols, HPLC-DAD phenolic acid profiles and in vitro biological activity of monovarietal Passerina del Frusinate white wines and the effect of different maceration times (0, 18 and 24 h were evaluated based on these parameters. Results highlighted statistically significant differences for almost all analysed parameters due to a strong influence of the pre-fermentative skin contact time. The flavan content of macerated wines was six times higher than that of the control, while total polyphenols were 1.5 times higher. According to their phytochemical content, macerated wines showed the highest antiradical capacity tested by means of DPPH• and ABTS+• assays. Besides, prolonged maceration resulted in a reduction of CIELab coordinates as well as of the content of phenolic substances and antiradical capacity. Among the phenolic acids analysed, the most abundant were vanillic acid and caffeic acid; the latter proved to be the most susceptible to degradation as a result of prolonged maceration. Passerina del Frusinate appears as a phenol-rich white wine with a strong antioxidant potential similar to that of red wines.

  12. Formation of manganese phosphate and manganese carbonate during long-term sorption of Mn(2+) by viable Shewanella putrefaciens: effects of contact time and temperature.

    Science.gov (United States)

    Chubar, Natalia; Avramut, Cristina; Visser, Tom

    2015-04-01

    The influence of temperature (5, 10, 22 and 30 °C) on the long-term (30 days) sorption of Mn(2+) by viable Shewanella putrefaciens was studied by FTIR and EXAFS. The additional Mn-removal capacity of these bacteria was found to result from the surface precipitation of Mn-containing inorganic phases. The chemical composition of the Mn-containing precipitates is temperature and contact-time dependent. Mn(ii) phosphate and Mn(ii) carbonate were the two major precipitates formed in 1000 mL batches at 10, 22 and 30 °C. The ratio of Mn(ii) phosphate to Mn(ii) carbonate was a function of the contact time. After 30 days, MnCO3 was the dominant phase in the precipitates at 10, 22 and 30 °C; however, MnCO3 did not form at 5 °C. Mn(ii) phosphate was the only precipitate formed at 5 °C over 30 days. The biosynthesis of Extracellular Polymeric Substances (EPS) was much greater at the lowest temperature (5 °C); however, these polymeric sugars did not contribute to the additional removal of Mn(ii) under the experimental conditions. This work is one of the first reports demonstrating the ability of microbes to bioprecipitate manganese phosphate and manganese carbonate. Because of the focus on interfacial processes, this is the first report showing a molecular-level mechanism for manganese carbonate formation (in contrast to the traditionally studied aged minerals).

  13. Effects of pH and hydraulic retention time on hydrogen production versus methanogenesis during anaerobic fermentation of organic household solid waste under extreme-thermophilic temperature (70 degrees C).

    Science.gov (United States)

    Liu, Dawei; Zeng, Raymond J; Angelidaki, Irini

    2008-08-15

    Two continuously stirred tank reactors were operated with household solid waste at 70 degrees C, for hydrogen and methane production. The individual effect of hydraulic retention time (HRT as 1, 2, 3, 4, and 6 days) at pH 7 or pH (5, 5.5, 6, 6.5, 7) at 3-day HRT was investigated on the hydrogen production versus methanogenesis. It was found that at pH 7, the maximum hydrogen yield was 107 mL-H(2)/g VS(added) (volatile solid added) but no stable hydrogen production was obtained as after some time methanogenesis was initiated at all tested HRTs. This demonstrated that sludge retention time alone was not enough for washing out the methanogens at pH 7 under extreme-thermophilic conditions. Oppositely, we showed that keeping the pH level at 5.5 was enough to inhibit methane and produce hydrogen stably at 3-day HRT. However, the maximum stable hydrogen yield was low at 21 mL-H(2)/g VS(added).

  14. Effects of pH and hydraulic retention time on hydrogen production versus methanogenesis during anaerobic fermentation of organic household solid waste under extreme-thermophilic temperature (70ºC)

    DEFF Research Database (Denmark)

    Liu, Dawei; Zeng, Raymond Jianxiong; Angelidaki, Irini

    2008-01-01

    Two continuously stirred tank reactors were operated with household solid waste at 70°C, for hydrogen and methane production. The individual effect of hydraulic retention time (HRT as 1, 2, 3, 4, and 6 days) at pH 7 or pH (5, 5.5, 6, 6.5, 7) at 3-day HRT was investigated on the hydrogen production...... versus methanogenesis. It was found that at pH 7, the maximum hydrogen yield was 107 mL-H2/g VSadded (volatile solid added) but no stable hydrogen production was obtained as after some time methanogenesis was initiated at all tested HRTs. This demonstrated that sludge retention time alone was not enough...... for washing out the methanogens at pH 7 under extreme-thermophilic conditions. Oppositely, we showed that keeping the pH level at 5.5 was enough to inhibit methane and produce hydrogen stably at 3-day HRT. However, the maximum stable hydrogen yield was low at 21 mL-H2/g VSadded. Biotechnol. Bioeng. 2008...

  15. "Meet and Greet and Then Treat" is No Fun: Is It Time To Reinvent No-Touch Greetings For Contact Precautions? A Personal Perspective

    Directory of Open Access Journals (Sweden)

    Deepak Gupta

    2015-03-01

    Full Text Available Cleanliness in general and in healthcare settings in particular as advocated by Centers for Disease Control and Prevention (CDC with hand-hygiene standards-guidelines bring forth the importance of culprit hands and how to take care of them. There is an unexplored (and potentially overlooked arena/avenue wherein neither you can strictly/religiously adhere to hand-hygiene (often given amiss by our natural prude psyche nor you can avoid thinking about it despite human being a social animal (how to else-greet without having to self-treat. Not only should oneself not waste time in prolonged civilities or greetings as advocated but also one should not allow those greetings lingering on to them through the exchanged visible or invisible fluids therein. What does this all may mean is that for example, hand-shaking may be easily replaced with hand-waving so that your mind does not immediately race to hand-washing; and hugging may be easily replaced with bowing so that you are not bowing to the contracted illnesses due to the contacted bodies. Finally what to say about kissing that may be avoided altogether when greeting strangers or may be limited for only those people whom you love so much that you are ready to get sick with them. In summary, general population with societal assent can re-invent No-Touch Greetings for contact precautions in regular livelihoods because meeting and greeting and then rushing for treating self is never fun.

  16. 离散时间 SM[K]/PH[K]/1/FCFS 排队系统的年龄过程改进分析%Analysis and Improvement of the Age Process in a Queuing System of Discrete Time SM[K]/PH[K]/1/FCFS

    Institute of Scientific and Technical Information of China (English)

    高卓; 徐德举

    2015-01-01

    We studied a discrete time queuing system with multiple types of customers and a first-come-first-served (FCFS) service discipline. Customers arrive according to a semi-Markov arrival process and the service times of individual customers have PH-distributions. We studied SM[K]/PH[K]/1/FCFS queue and analyzed its generalized age process particularly. We introduced some auxiliary variables to construct a Markov chain associated with ag(t) and obtained the transition probability matrix of this Markov chain.%基于一个离散时间的排队系统:顾客有着多种类型,成批到达,到达过程是一个半马尔可夫过程,按照先来先服务的准则,并且每一个顾客的服务时间服从各自的 PH 分布。对这个离散时间 SM[K]/PH[K]/1/FCFS 排队系统年龄过程进行了详细分析,引进一些附加变量构造一个关于年龄过程的马尔可夫链,从而计算出年龄过程的转移矩阵。

  17. Ph3CCOOSnPh3.Ph3PO AND Ph3CCOOSnPh3.Ph3AsO: SYNTHESIS AND INFRARED STUDY

    Directory of Open Access Journals (Sweden)

    ABDOU MBAYE

    2014-08-01

    Full Text Available The mixture of ethanolic solutions of Ph3CCOOSnPh3 and Ph3PO or Ph3AsO gives Ph3CCOOSnPh3.Ph3PO and Ph3CCOOSnPh3.Ph3AsO adducts which have been characterized by infrared spectroscopy. A discrete structure is suggested for both, the environment around the tin centre being trigonal bipyramidal, the triphenylacetate anion behaving as a mondentate ligand.

  18. Effects of forage neutral detergent fibre and time after feeding on medial and ventral rumen pH and volatile fatty acids concentration in heifers fed highly digestible grass/clover silages

    DEFF Research Database (Denmark)

    Schulze, A.K.S.; Storm, Adam Christian; Weisbjerg, Martin Riis

    2016-01-01

    -lactic acid, and ammonia to assess ruminal chemical gradient. Reticular contractions were continuously recorded by a pressure transducer. Time relative to feeding affected rumen parameters as pH was generally lower and VFA content greater in medial compared with ventral rumen fluid. Greater NDF content...... of the silage caused lower VFA concentration and higher pH in the rumen mat, and therefore the gradient diminished at greater NDF content in the silages; an effect probably caused by reduced organic matter digestibility rather than digesta NDF properties. This study therefore suggests that VFA production...

  19. When "In Your Face" Is Not Out of Place: The Effect of Timing of Disclosure of a Same-Sex Dating Partner under Conditions of Contact.

    Science.gov (United States)

    Dane, Sharon K; Masser, Barbara M; MacDonald, Geoff; Duck, Julie M

    2015-01-01

    In a series of experiments we examined heterosexuals' reactions to the timing of disclosure of a gender-matched confederate's same-sex dating partner. Disclosure occurred in a naturalistic context-that is, it occurred when meeting, or expecting to soon meet, a same-sex attracted individual, who voluntarily shared this information with the participant as a natural part of a broader topic of discussion. The confederate, when disclosing early rather than later, was approached more closely (Prestudy) and liked more (Studies 1-2). Those experiencing early disclosure, compared with later, were less drawn to topics of lower intimacy (Study 1), were happier and more excited about meeting the confederate, and more likely to choose to be alone with the confederate for a one-on-one discussion (Study 2). Further, women experiencing early disclosure were more willing to introduce the same-gender confederate to their friends (Study 2). The benefits of knowing sooner, rather than later, continued to apply even when participants were given further time to process the disclosure. To explore the underlying reasons for the more favorable experiences of upfront disclosure, we examined participants' memory of the information shared by the confederate (Study 3). Results revealed that those who experienced delayed disclosure were more likely to incorrectly recall and negatively embellish information related to the confederate's sexual orientation, suggesting that early disclosure resulted in a reduced tendency to focus on the confederate's sexuality as a defining feature. These positive findings for early timing are discussed in light of previous studies that have found benefits for delayed disclosure and those that have failed to investigate the effects of timing of 'coming out' under conditions of contact.

  20. When "In Your Face" Is Not Out of Place: The Effect of Timing of Disclosure of a Same-Sex Dating Partner under Conditions of Contact.

    Directory of Open Access Journals (Sweden)

    Sharon K Dane

    Full Text Available In a series of experiments we examined heterosexuals' reactions to the timing of disclosure of a gender-matched confederate's same-sex dating partner. Disclosure occurred in a naturalistic context-that is, it occurred when meeting, or expecting to soon meet, a same-sex attracted individual, who voluntarily shared this information with the participant as a natural part of a broader topic of discussion. The confederate, when disclosing early rather than later, was approached more closely (Prestudy and liked more (Studies 1-2. Those experiencing early disclosure, compared with later, were less drawn to topics of lower intimacy (Study 1, were happier and more excited about meeting the confederate, and more likely to choose to be alone with the confederate for a one-on-one discussion (Study 2. Further, women experiencing early disclosure were more willing to introduce the same-gender confederate to their friends (Study 2. The benefits of knowing sooner, rather than later, continued to apply even when participants were given further time to process the disclosure. To explore the underlying reasons for the more favorable experiences of upfront disclosure, we examined participants' memory of the information shared by the confederate (Study 3. Results revealed that those who experienced delayed disclosure were more likely to incorrectly recall and negatively embellish information related to the confederate's sexual orientation, suggesting that early disclosure resulted in a reduced tendency to focus on the confederate's sexuality as a defining feature. These positive findings for early timing are discussed in light of previous studies that have found benefits for delayed disclosure and those that have failed to investigate the effects of timing of 'coming out' under conditions of contact.

  1. A Self-Powered Triboelectric Nanosensor for PH Detection

    Directory of Open Access Journals (Sweden)

    Ying Wu

    2016-01-01

    Full Text Available A self-powered, sliding electrification based triboelectric sensor was developed for detecting PH value from a periodic contact/separation motion. This innovative, cost-effective, simply designed sensor is composed of a fluorinated ethylene propylene thin film and an array of electrodes underneath. The operation of the TENG (triboelectric nanogenerator sensor relies on a repetitive emerging-submerging process with traveling solution waves, in which the coupling between triboelectrification and electrostatic induction gives rise to alternating flows of electrons between electrodes. On the basis of coupling effect between triboelectrification and electrostatic induction, the sensor generates electric output signals which are associated with PH value. Experimental results show that the output voltage of the TENG sensor increases with the increasing PH value, which indicate that the PH value of different solution can be real-time monitored. This work not only demonstrates a new principle in the field of PH value measurement but also greatly expands the applicability of triboelectric nanogenerator (TENG as self-powered sensors.

  2. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... to drive for eight weeks," she said. "I now live with a corneal scar, vision damage and a drooping eyelid." To safely wear costume contact lenses for Halloween or any time of year, follow these guidelines: Get an eye ...

  3. Relaxation of the MCL after an Open-Wedge High Tibial Osteotomy results in decreasing contact pressures of the knee over time.

    Science.gov (United States)

    van Egmond, N; Hannink, G; Janssen, D; Vrancken, A C; Verdonschot, N; van Kampen, A

    2017-03-01

    The objective of this study was to investigate the effect of a medial open-wedge osteotomy (OWO) and the release of the superficial medial collateral ligament (MCL) on the tibiofemoral cartilage pressure, the MCL tension and the valgus laxity of the knee. Seven fresh-frozen, human cadaveric knees were used. Medial and lateral mean contact pressure (CP), peak contact pressure (peakCP), and contact area (CA) were measured using a pressure-sensitive film (I-Scan; Tekscan, Boston, MA). The MCL tension was measured using a custom-made device. These measurements were continuously recorded for 5 min after an OWO of 10°. After the osteotomy, the valgus laxity was measured with a handheld Newtonmeter. For one knee, the measurements were continued for 24 h. At the end, a complete release of the superficial MCL was performed and the measurements were repeated at 10°. There was relaxation of the MCL after the osteotomy; the tension dropped in 5 min with 10.7% (mean difference 20.5 N (95% CI 16.1-24.9)), and in 24 h, the tension decreased by 24.2% (absolute difference 38.8 N) (one knee). After the osteotomy, the mean CP, peakCP and CA increased in the medial compartment (absolute difference 0.17 MPa (95% CI 0.14-0.20), 0.27 MPa (95% CI 0.24-0.30), 132.9mm(2) (95% CI 67.7-198.2), respectively), and decreased in the lateral compartment (absolute difference 0.02 MPa (95% CI 0.03 -0.01), 0.08 MPa (95% CI 0.11 - 0.04), 47.0 mm(2) (95% CI -105.8 to 11.8), respectively). Only after a release of the superficial MCL, the mean CP, peak CP and CA significantly decreased in the medial compartment (absolute difference 0.17, 0.27 MPa, 119.8 mm(2), respectively), and increased in the lateral compartment (absolute difference 0.02, 0.11 MPa, 52.4 mm(2), respectively). After the release of the superficial MCL, a mean increase of 7.9° [mean difference - 0.1° (95% CI -1.9 to 1.6)] of the valgus laxity was found. A release of the superficial MCL helps achieve the goal of

  4. Metal-ion pillared clays as hydrocracking catalysts (II): effect of contact time on products from coal extracts and petroleum distillation residues

    Energy Technology Data Exchange (ETDEWEB)

    S.D. Bodman; W.R. McWhinnie; V. Begon; M. Millan; I. Suelves; M.-J. Lazaro; A.A. Herod; R. Kandiyoti [Aston University, Birmingham (United Kingdom). Department of Chemical Engineering and Applied Chemistry

    2003-11-01

    Novel catalysts have been prepared, based on montmorillonite (a natural clay) and laponite (a synthetic clay) pillared with tin, chromium and aluminium pillars as well as layered double hydroxides based on polyoxo-vanadate and -molybdate as previously described. These novel catalysts were compared initially with a standard Ni/Mo catalyst supported on alumina and a dispersed catalyst, Mo(CO){sub 6} in hydrocracking a coal extract for a short contact time of 10 min at 440{sup o}C in a microbomb reactor with tetralin solvent and hydrogen at a pressure of 190 bar. In the present work, the best of the novel catalysts, chromium montmorillonite calcined at 500{sup o}C and tin laponite, have been compared with the supported catalyst and a dispersed catalyst (Mo(CO){sub 6}) in the repeated hydrocracking of fresh coal extract over three sequential periods of 1 h. Also, the chromium montmorillonite calcined at 500{sup o}C has been used in the hydrocracking of primary coal extracts, prepared in the flowing solvent liquefaction rig from Pittsburgh No. 8 and Illinois No. 6 coals, for reaction times of 10 min and 2 h. Further, the chromium montmorillonite calcined at 500{sup o}C and tin laponite, have been compared with the supported catalyst and in the absence of a catalyst, in the hydrocracking of a petroleum distillation residue with 10 min and 2 h reaction times. Results were compared by size exclusion chromatography in NMP solvent and by UV-fluorescence and evaluated by the extent of the shift of the SEC profile to small molecules and by the shift of the synchronous UV-fluorescence profiles to shorter wavelengths. The performances of both catalysts at short, long or repeated reaction times are seen to be better than that of the conventional NiMo catalyst for the hydrocracking of coal-derived materials and a petroleum residue. Trials on a longer time scale are necessary in the next level of evaluation. 37 refs., 14 figs., 1 tab.

  5. Time-Varying Total Stiffness Matrix of a Rigid Machine Spindle-Angular Contact Ball Bearings Assembly: Theory and Analytical/Experimental Verifications

    Directory of Open Access Journals (Sweden)

    Fawzi M.A. El-Saeidy

    2011-01-01

    Full Text Available A lagrangian formulation is presented for the total dynamic stiffness and damping matrices of a rigid rotor carrying noncentral rigid disk and supported on angular contact ball bearings (ACBBs. The bearing dynamic stiffness/damping marix is derived in terms of the bearing motions (displacements/rotations and then the principal of virtual work is used to transfer it from the bearing location to the rotor mass center to obtain the total dynamic stiffness/damping matrix. The bearing analyses take into account the bearing nonlinearities, cage rotation and bearing axial preload. The coefficients of these time-dependent matrices are presented analytically. The equations of motion of a rigid rotor-ACBBs assembly are derived using Lagrange's equation. The proposed analyses on deriving the bearing stiffness matrix are verified against existing bearing analyses of SKF researchers that, in turn, were verified using both SKF softwares/experiments and we obtained typical agreements. The presented total stiffness matrix is applied to a typical grinding machine spindle studied experimentally by other researchers and excellent agreements are obtained between our analytical eigenvalues and the experimental ones. The effect of using the total full stiffness matrix versus using the total diagonal stiffness matrix on the natural frequencies and dynamic response of the rigid rotor-bearings system is studied. It is found that using the diagonal matrix affects natural frequencies values (except the axial frequency and response amplitudes and pattern and causes important vibration tones to be missig from the response spectrum. Therefore it is recommended to use the full total stiffness matrix and not the diagonal matrix in the design/vibration analysis of these rotating machines. For a machine spindle-ACBBs assembly under mass unbalnce and a horizontal force at the spindle cutting nose when the bearing time-varying stiffness matrix (bearing cage rotation is considered

  6. ALLERGIC CONTACT DERMATITIS

    Directory of Open Access Journals (Sweden)

    Trisna Yuliharti Tersinanda

    2013-07-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Allergic contact dermatitis is an immunologic reaction that tends to involve the surrounding skin and may even spread beyond affected sites. This skin disease is one of the more frequent, and costly dermatologic problems. Recent data from United Kingdom and United States suggest that the percentage of occupational contact dermatitis due to allergy may be much higher, thus raising the economic impact of occupational allergic contact dermatitis. There is not enough data about the epidemiology of allergic contact dermatitis in Indonesia, however based on research that include beautician in Denpasar, about 27,6 percent had side effect of cosmetics, which is 25,4 percent of it manifested as allergic contact dermatitis. Diagnosis of allergic contact dermatitis is based on anamnesis, physical examination, patch test, and this disease should be distinguished from other eczematous skin disease. The management is prevention of allergen exposure, symptomatic treatment, and physicochemical barrier /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  7. Effect of contact time and the use of hydroxypropyl-β-cyclodextrin in the removal of fluorene and fluoranthene from contaminated soils.

    Science.gov (United States)

    Morillo, E; Sánchez-Trujillo, M A; Villaverde, J; Madrid, F; Undabeytia, T

    2014-10-15

    Sorption-desorption experiments of fluorene (FLU) and fluoranthene (FLT) in soils were carried out and correlated to their removal from aged contaminated soils using aqueous solutions in the absence and in the presence of hydroxypropyl-β-cyclodextrin (HPBCD) as the extraction agent. FLU became more resistant to extraction in aged contaminated soils due to its initial adsorption onto the mineral and amorphous soil organic matter (SOM) domains, sites of lower binding energy from which, due to its small size, it could spread towards the condensed SOM as the contact time increased. Therefore, FLU will not be easily desorbed from aged contaminated soils due to physical entrapment mechanisms, even when using HPBCD as extractant, presenting FLU low risks to the environment. On the contrary, FLT was extracted from aged soils in the presence of HPBCD in solutions to a much greater extent than in its absence. Due to its more hydrophobic character FLT sorption in soils was relatively quicker, remaining more or less fixed on hydrophobic sites of the organic matter (OM) with different energies, and therefore the amount of FLT extracted was almost constant for different ageing times. During extraction experiments, the influence of the OM quality of the soils was also highlighted because an inverse proportionality between OM content of soil and extractability of sorbed FLT was observed. It was concluded that soils with lower OM content that had more diagenetically processed OM could block the extraction of FLT more effectively than soils with higher OM content that are less humified. This indicates the need to use not only adsorption-desorption data in contaminant fate and transport models, but also extraction studies in aged contaminated soils and other complementary analytical approaches when assessing soil contamination-related risks. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Lipstick Induced Contact Leucoderma

    OpenAIRE

    Gupta Lalit Kumar; Jain Suresh Kumar; Khare Ashok Kumar

    2001-01-01

    Lipstick is a commonly used cosmetic. Its use may sometimes lead to contact dermatitis. Contact leucoderma to lipsticks however, is not common. We report a patient developing contact leucoderma to lipstick in association with contact dermatitis.

  9. Lipstick Induced Contact Leucoderma

    Directory of Open Access Journals (Sweden)

    Gupta Lalit Kumar

    2001-01-01

    Full Text Available Lipstick is a commonly used cosmetic. Its use may sometimes lead to contact dermatitis. Contact leucoderma to lipsticks however, is not common. We report a patient developing contact leucoderma to lipstick in association with contact dermatitis.

  10. The complementary power of pH and lake-water organic carbon reconstructions for discerning the influences on surface waters across decadal to millennial time scales

    Directory of Open Access Journals (Sweden)

    P. Rosén

    2011-09-01

    Full Text Available Lysevatten, a lake in southwest Sweden, has experienced both acidification and recent changes in the amount of lake-water organic carbon (TOC, both causing concern across Europe and North America. A range of paleolimnological tools – diatom-inferred pH, inferred lake-water TOC from visible-near-infrared spectroscopy (VNIRS, multi-element geochemistry and pollen analysis, combined with geochemical modeling were used to reconstruct the lake's chemistry and surroundings back to the most recent deglaciation 12 500 years ago. The results reveal that the recent anthropogenic impacts are similar in magnitude to the long-term variation driven by natural catchment changes and early agricultural land use occurring over centuries and millennia. The combined reconstruction of both lake-water TOC and lithogenic element delivery can explain the major changes in lake-water pH and modeled acid neutralizing capacity during the past 12 500 years. The results raise important questions regarding what precisely comprises "reference" conditions (i.e., free from human impacts as defined in the European Water Framework Directive.

  11. EDITORIAL: Close contact Close contact

    Science.gov (United States)

    Demming, Anna

    2010-07-01

    The development of scanning probe techniques, such as scanning tunnelling microscopy [1], has often been touted as the catalyst for the surge in activity and progress in nanoscale science and technology. Images of nanoscale structural detail have served as an invaluable investigative resource and continue to fascinate with the fantastical reality of an intricate nether world existing all around us, but hidden from view of the naked eye by a disparity in scale. As is so often the case, the invention of the scanning tunnelling microscope heralded far more than just a useful new apparatus, it demonstrated the scope for exploiting the subtleties of electronic contact. The shrinking of electronic devices has been a driving force for research into molecular electronics, in which an understanding of the nature of electronic contact at junctions is crucial. In response, the number of experimental techniques in molecular electronics has increased rapidly in recent years. Scanning tunnelling microscopes have been used to study electron transfer through molecular films on a conducting substrate, and the need to monitor the contact force of scanning tunnelling electrodes led to the use of atomic force microscopy probes coated in a conducting layer as studied by Cui and colleagues in Arizona [2]. In this issue a collaboration of researchers at Delft University and Leiden University in the Netherlands report a new device architecture for the independent mechanical and electrostatic tuning of nanoscale charge transport, which will enable thorough studies of molecular transport in the future [3]. Scanning probes can also be used to pattern surfaces, such as through spatially-localized Suzuki and Heck reactions in chemical scanning probe lithography. Mechanistic aspects of spatially confined Suzuki and Heck chemistry are also reported in this issue by researchers in Oxford [4]. All these developments in molecular electronics fabrication and characterization provide alternative

  12. Hysteresis during contact angles measurement.

    Science.gov (United States)

    Diaz, M Elena; Fuentes, Javier; Cerro, Ramon L; Savage, Michael D

    2010-03-15

    A theory, based on the presence of an adsorbed film in the vicinity of the triple contact line, provides a molecular interpretation of intrinsic hysteresis during the measurement of static contact angles. Static contact angles are measured by placing a sessile drop on top of a flat solid surface. If the solid surface has not been previously in contact with a vapor phase saturated with the molecules of the liquid phase, the solid surface is free of adsorbed liquid molecules. In the absence of an adsorbed film, molecular forces configure an advancing contact angle larger than the static contact angle. After some time, due to an evaporation/adsorption process, the interface of the drop coexists with an adsorbed film of liquid molecules as part of the equilibrium configuration, denoted as the static contact angle. This equilibrium configuration is metastable because the droplet has a larger vapor pressure than the surrounding flat film. As the drop evaporates, the vapor/liquid interface contracts and the apparent contact line moves towards the center of the drop. During this process, the film left behind is thicker than the adsorbed film and molecular attraction results in a receding contact angle, smaller than the equilibrium contact angle.

  13. Hydrogen production with short contact time. Catalytic partial oxidation of hydrocarbons and oxygenated compounds: Recent advances in pilot- and bench-scale testing and process design

    Energy Technology Data Exchange (ETDEWEB)

    Guarinoni, A.; Ponzo, R.; Basini, L. [ENI Refining and Marketing Div., San Donato Milanese (Italy)

    2010-12-30

    ENI R and D has been active for fifteen years in the development of Short Contact Time - Catalytic Partial Oxidation (SCT-CPO) technologies for producing Hydrogen/Synthesis Gas. From the beginning the experimental work addressed either at defining the fundamental principles or the technical and economical potential of the technology. Good experimental responses, technical solutions' simplicity and flexibility, favourable techno-economical evaluations promoted the progressive widening of the field of the investigations. From Natural Gas (NG) the range of ''processable'' Hydrocarbons extended to Liquefied Petroleum Gas (LPG) and Gasoils, including those characterised by high levels of unsaturated and sulphurated molecules and, lately, to other compounds with biological origin. The extensive work led to the definition of different technological solutions, grouped as follows: Technology 1: Air Blown SCT-CPO of Gaseous Hydrocarbons and/or Light Compounds with biological origin Technology 2: Enriched Air/Oxygen Blown SCT-CPO of Gaseous Hydrocarbons and/or Light Compounds with biological origin Technology 3: Enriched Air/Oxygen Blown SCT-CPO of Liquid Hydrocarbons and/or Compounds with biological origin Recently, the licence rights on a non-exclusive basis for the commercialisation of SCT-CPO based processes for H{sub 2}/Synthesis gas production from light hydrocarbons with production capacity lower than 5,000 Nm{sup 3}/h of H{sub 2} or 7,500 Nm3/h of syngas have been assigned to two external companies. In parallel, development of medium- and large-scale plant solutions is progressing within the ENI group framework. These last activities are addressed to the utilisation of SCT-CPO for matching the variable Hydrogen demand in several contexts of oil refining operation. This paper will report on the current status of SCT-CPO with a focus on experimental results obtained, either at pilot- and bench- scale level. (orig.)

  14. Contact Graph Routing

    Science.gov (United States)

    Burleigh, Scott C.

    2011-01-01

    Contact Graph Routing (CGR) is a dynamic routing system that computes routes through a time-varying topology of scheduled communication contacts in a network based on the DTN (Delay-Tolerant Networking) architecture. It is designed to enable dynamic selection of data transmission routes in a space network based on DTN. This dynamic responsiveness in route computation should be significantly more effective and less expensive than static routing, increasing total data return while at the same time reducing mission operations cost and risk. The basic strategy of CGR is to take advantage of the fact that, since flight mission communication operations are planned in detail, the communication routes between any pair of bundle agents in a population of nodes that have all been informed of one another's plans can be inferred from those plans rather than discovered via dialogue (which is impractical over long one-way-light-time space links). Messages that convey this planning information are used to construct contact graphs (time-varying models of network connectivity) from which CGR automatically computes efficient routes for bundles. Automatic route selection increases the flexibility and resilience of the space network, simplifying cross-support and reducing mission management costs. Note that there are no routing tables in Contact Graph Routing. The best route for a bundle destined for a given node may routinely be different from the best route for a different bundle destined for the same node, depending on bundle priority, bundle expiration time, and changes in the current lengths of transmission queues for neighboring nodes; routes must be computed individually for each bundle, from the Bundle Protocol agent's current network connectivity model for the bundle s destination node (the contact graph). Clearly this places a premium on optimizing the implementation of the route computation algorithm. The scalability of CGR to very large networks remains a research topic

  15. Highly Sensitive and Wide-Dynamic-Range Multichannel Optical-Fiber pH Sensor Based on PWM Technique.

    Science.gov (United States)

    Khan, Md Rajibur Rahaman; Kang, Shin-Won

    2016-11-09

    In this study, we propose a highly sensitive multichannel pH sensor that is based on an optical-fiber pulse width modulation (PWM) technique. According to the optical-fiber PWM method, the received sensing signal's pulse width changes when the optical-fiber pH sensing-element of the array comes into contact with pH buffer solutions. The proposed optical-fiber PWM pH-sensing system offers a linear sensing response over a wide range of pH values from 2 to 12, with a high pH-sensing ability. The sensitivity of the proposed pH sensor is 0.46 µs/pH, and the correlation coefficient R² is approximately 0.997. Additional advantages of the proposed optical-fiber PWM pH sensor include a short/fast response-time of about 8 s, good reproducibility properties with a relative standard deviation (RSD) of about 0.019, easy fabrication, low cost, small size, reusability of the optical-fiber sensing-element, and the capability of remote sensing. Finally, the performance of the proposed PWM pH sensor was compared with that of potentiometric, optical-fiber modal interferometer, and optical-fiber Fabry-Perot interferometer pH sensors with respect to dynamic range width, linearity as well as response and recovery times. We observed that the proposed sensing systems have better sensing abilities than the above-mentioned pH sensors.

  16. 非接触动态实时视线跟踪技术%Non-Contact Dynamic Real-Time Eye Tracking Technology

    Institute of Scientific and Technical Information of China (English)

    王向军; 蔡方方; 刘峰; 李洋

    2015-01-01

    The eye tracking is the key technology of intelligent eye movement operating system, which is also the basis that enables eye movement operating system to be the advanced human-machine interactive applications. This paper gives a more comprehensive vision of the development of non-contact eye tracking technology, and introduces the non-contact eye gaze tracking technology that enables to achieve real-time dynamic eye tracking or gaze point estimation, including 2D eye tracking methods, 3D eye tracking methods and model-based 3D methods. Comparing and analyzing new development of the existing methods mentioned above, this paper illustrates the scientific prob-lems that eye tracking technology currently faces, and presents a novel head-mounted free space eye tracking method based on binocular stereo vision. The conclusion is that eye tracking technology should meet intelligent human-machine interactive approach based on eye movement operating system expands to free space. The eye tracking technology develops towards high-precision, easy to configure and wider range of sight in free space measurement.%视线跟踪技术是智能眼动操作系统的关键技术,是实现先进眼动操作系统作为高级人机交互应用的基础和前提。较为完整地阐述了非接触式视线跟踪技术的发展历程,并详细介绍了现有的实现视线或注视点实时动态跟踪测量的非接触视线跟踪技术,包括2D视线跟踪方法、3D视线跟踪方法和基于3D模型的视线跟踪方法。通过分析和比较现有的三类方法的最新进展,介绍了视线跟踪技术目前面临的科学问题,提出了基于双目立体视觉的头戴式自由空间视线跟踪测量方法,指出了视线跟踪技术应满足基于眼动操作系统的智能人机交互方法向自由空间操作发展的需求,朝着高精度、易配置、更大视线活动范围的自由空间视线测量方向发展。

  17. Contact: Releasing the news

    Science.gov (United States)

    Pinotti, Roberto

    The problem of mass behavior after man's future contacts with other intelligences in the universe is not only a challenge for social scientists and political leaders all over the world, but also a cultural time bomb as well. In fact, since the impact of CETI (Contact with Extraterrestrial Intelligence) on human civilization, with its different cultures, might cause a serious socio-anthropological shock, a common and predetermined worldwide strategy is necessary in releasing the news after the contact, in order to keep possible manifestations of fear, panic and hysteria under control. An analysis of past studies in this field and of parallel historical situations as analogs suggests a definite "authority crisis" in the public as a direct consequence of an unexpected release of the news, involving a devastating "chain reaction" process (from both the psychological and sociological viewpoints) of anomie and maybe the collapse of today's society. The only way to prevent all this is to prepare the world's public opinion concerning contact before releasing the news, and to develop a long-term strategy through the combined efforts of scientists, political leaders, intelligence agencies and the mass media, in order to create the cultural conditions in which a confrontation with ETI won't affect mankind in a traumatic way. Definite roles and tasks in this multi-level model are suggested.

  18. Anaerobic digestion of the vinasses from the fermentation of Agave tequilana Weber to tequila: The effect of pH, temperature and hydraulic retention time on the production of hydrogen and methane

    Energy Technology Data Exchange (ETDEWEB)

    Espinoza-Escalante, Froylan M.; Pelayo-Ortiz, Carlos; Navarro-Corona, Jose; Gonzalez-Garcia, Yolanda [Department of Chemical Engineering, University of Guadalajara, Blvd. M. Garcia Barragan No. 1421, Guadalajara CP 44430 (Mexico); Bories, Andre [INRA-Unite Experimentale de Pech-Rouge, 11430 Gruissan (France); Gutierrez-Pulido, Humberto [Department of Mathematics, University of Guadalajara, Blvd. M. Garcia Barragan No. 1421, Guadalajara CP 44430 (Mexico)

    2009-01-15

    The objective of this work was to study the effect of three operational parameters (pH, hydraulic retention time (HRT) and growing temperature) on a semi-continuous bioreactor treating Tequila's vinasses by anaerobic digestion (AD). The response was measured through four response variables: total reducing sugars (TRS) consumption, VFA's, hydrogen and methane production. Trials were done according to a factorial design. The experimental results were studied through a multiple response optimization (MRO) analysis to find single and multiple optimums for the above-mentioned variables. Mathematical models that can describe the effect of the operational parameters on each response variable were found. In this study it is shown that hydrogen production is favored at thermophilic growth (55 C), operating the reactor at a slight acidic pH range and at the higher HRT in the boundaries of the experimental region. (author)

  19. Association between Contact allergy and Psoriasis

    DEFF Research Database (Denmark)

    Bangsgaard, Nannie

    2011-01-01

    6. SUMMERY 6.1 Summery in English Allergic contact dermatitis (ACD) and psoriasis are the two most prevalent skin diseases in the western world. ACD is the clinical manifestation of contact allergy. Contact allergy and psoriasis are both due to inflammatory mechanisms involving the innate...... and adaptive immune system. Psoriasis is conceived to be an autoimmune disease. Recent studies have suggested an inverse relation between contact allergy and autoimmune diseases. The association between contact allergy and psoriasis could reveal mechanistic insights into both inflammatory processes....... The overall aim of this PhD study was to investigate the association between contact allergy and autoimmune disease, with focus on psoriasis. The work was done in three study parts. Part I Epidemiological studies. Part II Sensitization study and Part III Experimental studies. In part I the association between...

  20. Temperature and pH dual-responsive POEGMA-based coatings for protein adsorption.

    Science.gov (United States)

    Stetsyshyn, Yurij; Fornal, Katarzyna; Raczkowska, Joanna; Zemla, Joanna; Kostruba, Andrij; Ohar, Halyna; Ohar, Mariya; Donchak, Volodymyr; Harhay, Khrystyna; Awsiuk, Kamil; Rysz, Jakub; Bernasik, Andrzej; Budkowski, Andrzej

    2013-12-01

    Poly(oligo(ethylene glycol)ethyl ether methacrylate (POEGMA246) coatings were successfully fabricated using novel approach via polymerization from oligoperoxide grafted to premodified glass substrate. Wettability, content and composition of coatings fabricated with different polymerization times were determined using contact angle measurements, ellipsometry and Time of Flight-Secondary Ion Mass Spectrometry (TOF-SIMS). Thermo- and pH-responsive properties of POEGMA246 coatings were found to depend significantly on concentration of the grafted POEGMA246. Coatings fabricated with polymerization time 30 h exhibit not only temperature- but also pH-dependence of wettability. Thermal response of wettability, measured between 20 and 32°C, was prominent at pH 9 and 7 and diminished or was absent at pH 5 and 3, indicating a transition between hydrated loose coils and hydrophobic collapsed chains, blocked at low pH. Protein adsorption, observed by fluorescence microscopy and analyzed semi-quantitatively using integral geometry approach, decreased dramatically for model protein (lentil lectin labeled with fluorescein isothiocyanate) at transition from pH 5 to pH 9, showing only very weak thermal-dependence. Strong protein adsorption response to pH and very weak one to temperature was confirmed by TOF-SIMS and Principal Component Analysis. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. The effect of reuterin on the lag time of single cells of Listeria innocua grown on a solid agar surface at different pH and NaCl concentrations

    DEFF Research Database (Denmark)

    Rasch, Maria; Metris, A.; Baranyi, J.

    2007-01-01

    The lag time of single cells of Listeria innocua grown on the surface of Brain Heart Infusion Agar was studied by microscopy and image analysis. An experimental set-up that enabled relocation of the cells on the agar surface was developed and used to collect data from 50 to 100 individual cells...... at a time. Reuterin was added at different concentrations (0-10[no-break space]AU/ml) and it was observed that it increased both the lag time of the cells and its variance. Furthermore, for a large proportion of cells, reuterin completely prevented the cell division within the time of observation. Reuterin...... in combination with low pH inhibited the cell division even more efficiently. A similar effect was observed for the combination of reuterin and sodium chloride. Our experimental set-up provides a good model system for generating data on the lag time of single cells on solid surfaces, which can improve...

  2. Dynamic behavior of the water droplet impact on a textured hydrophobic/superhydrophobic surface: the effect of the remaining liquid film arising on the pillars' tops on the contact time.

    Science.gov (United States)

    Li, Xiying; Ma, Xuehu; Lan, Zhong

    2010-04-06

    We have fabricated a series of textured silicon surfaces decorated by square arrays of pillars whose radius and pitch can be adjusted independently. These surfaces possessed a hydrophobic/superhydrophobic property after silanization. The dynamic behavior of water droplets impacting these structured surfaces was examined using a high-speed camera. Experimental results validated that the remaining liquid film on the pillars' tops gave rise to a wet surface instead of a dry surface as the water droplet began to recede away from the textured surfaces. Also, experimental results demonstrated that the difference in the contact time was subjected to the solid fraction referred to as the ratio of the actual area contacting with the liquid to its projected area on the textured surface. Because the mechanism by which the residual liquid film emerges on the pillars' tops can essentially be ascribed to the pinch-off of the liquid threads, we further addressed the changes in the contact time in terms of the characteristic time of pinch-off of an imaginary liquid cylinder whose radius is related to the solid fraction and the maximum contact area. The match of the theoretical analysis and the experimental results substantiates the assumption aforementioned.

  3. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Vision and Daily Eye Drops After One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume Contacts May Contain Chemicals ...

  4. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses ...

  5. Expression patterns of WT-1 and Bcr-Abl measured by TaqMan quantitative real-time RT-PCR during follow-up of leukemia patients with the Ph chromosome

    Institute of Scientific and Technical Information of China (English)

    CHEN Zi-xing陈子兴; Jaspal Kaeda; Sue Saunders; John M Goldman

    2004-01-01

    Background This study was designed to quantitatively measure WT-1 expression levels in patients with chronic myelogenous leukemia (CML) and acute lymphoblastic leukemia (ALL) during follow-up and to clarify the value of WT-1 as a molecular marker in minimal residual disease monitoring.Methods The TaqMan quantitative real-time RT-PCR method was established by using cloned WT-1 cDNA or synthesized oligonucleotides resembling WT-1 cDNA fragments in limit dilution as template until a stable and reliable standard curve was obtained. In a 25-month follow-up, the transcriptional levels of WT-1, Bcr-Abl, and Abl gene, were quantitatively measured in bone marrow cells from 25 CML or acute lymphoblastic leukemia (ALL) patients with the Ph chromosome. In addition, the expression of these genes in 40 samples of normal peripheral blood was also examined using the same method. The ratios of WT-1/Abl and Bcr-Abl/Abl were both plotted, and the two expression patterns were compared as well as their clinical significance.Results The levels of WT-1 expression in normal peripheral blood were detectable. In CML and Ph positive ALL patients, WT-1 expression levels changed in parallel with the Bcr-Abl expression pattern as the disease progressed or responded to effective treatment.Conclusion WT-1 expression provides a novel molecular marker in addition to Bcr-Abl for monitoring minimal residual disease (MRD) and targeting therapy in Ph chromosome-positive leukemia patients.

  6. Aspects of tests and assessment of filtering materials used for respiratory protection against bioaerosols. Part I: type of active substance, contact time, microorganism species.

    Science.gov (United States)

    Majchrzycka, Katarzyna; Gutarowska, Beata; Brochocka, Agnieszka

    2010-01-01

    This paper presents the results of a study on antimicrobial activity of polymer filter nonwovens produced by needle-punching or melt-blowing with an addition of disinfecting agents. The first part of the paper discusses how the biocidal activity of nonwovens is a function of the active agent added to the nonwovens, the duration of the contact of microorganisms with nonwovens and the type of microorganisms. The types of fibres and disinfecting agents had a considerable effect on the biocidal activity of nonwovens. The biocidal effect of nonwovens increased with the duration of their contact with microorganisms. Fibre activity differed considerably depending on the species of the microorganism. The microorganisms most sensitive to biocidal activity of the active filter nonwoven were S. aureus, M. flavus and E. coli. There were no biocidal effects on spore-forming bacterium B. subtilis.

  7. Fabricating customized hydrogel contact lens

    Science.gov (United States)

    Childs, Andre; Li, Hao; Lewittes, Daniella M.; Dong, Biqin; Liu, Wenzhong; Shu, Xiao; Sun, Cheng; Zhang, Hao F.

    2016-10-01

    Contact lenses are increasingly used in laboratories for in vivo animal retinal imaging and pre-clinical studies. The lens shapes often need modification to optimally fit corneas of individual test subjects. However, the choices from commercially available contact lenses are rather limited. Here, we report a flexible method to fabricate customized hydrogel contact lenses. We showed that the fabricated hydrogel is highly transparent, with refractive indices ranging from 1.42 to 1.45 in the spectra range from 400 nm to 800 nm. The Young’s modulus (1.47 MPa) and hydrophobicity (with a sessile drop contact angle of 40.5°) have also been characterized experimentally. Retinal imaging using optical coherence tomography in rats wearing our customized contact lenses has the quality comparable to the control case without the contact lens. Our method could significantly reduce the cost and the lead time for fabricating soft contact lenses with customized shapes, and benefit the laboratorial-used contact lenses in pre-clinical studies.

  8. Hidrólise da uréia em latossolos: efeito da concentração de uréia, temperatura, pH, armazenamento e tempo de incubação Urea hydrolysis in oxisols: effects of substrate concentration, temperature, pH, incubation time and storage conditions

    Directory of Open Access Journals (Sweden)

    Regina Marcia Longo

    2005-07-01

    Full Text Available Este trabalho objetivou estudar a velocidade de hidrólise da uréia em dois diferentes solos brasileiros (Latossolo Vermelho Aluminoférrico típico e Latossolo Vermelho distrófico típico onde foram realizados ensaios sobre o efeito do tempo e condições de armazenamento, concentração do substrato (uréia, temperatura, pH e tempo de incubação sobre a atividade da urease. As melhores condições de armazenamento foram em temperatura ambiente ou 5 ºC, após secagem ao ar, por um período de até 7 dias; para as condições estudadas, o melhor tempo de incubação foi de uma hora a 25-30 ºC, sem a utilização de tampão para acertar o pH, e a concentração de uréia suficiente foi de 3,30 g L-1, para o Latossolo Vermelho Aluminoférrico típico, e de 2,5 g L-1, para o Latossolo Vermelho distrófico típico para obter a velocidade máxima da enzima.This study evaluated the kinetics of urease hydrolysis in two different Brazilian soils (Rhodic Oxisols: a typic alumino-ferric Red Latossol and a typic distrophic Red Latosol. The trials were carried out to study the effects of air drying, soil sampling, storage conditions and temperature, pH, time of incubation, and substrate concentration on the urease activity. Results showed that best conditions for soil sample storage after air-drying for a 7-day period were at room temperature or at a temperature of 5 ºC. For the studied conditions the best incubation time was one hour at 25-30 ºC, without pH buffering. The ideal urea concentration suggested for the detection of the maximum velocity was 3.3 g L-1 for the typic alumino-ferric Red Latossol and 2.5 g L-1 for the typic distrophic Red Latosol.

  9. Microscopic monitoring of extracellular pH in dental biofilms

    DEFF Research Database (Denmark)

    Schlafer, Sebastian; Garcia, Javier; Greve, Matilde

    pH in dental biofilm is a key virulence factor for the development of caries lesions. The complex three-dimensional architecture of dental biofilms leads to steep gradients of nutrients and metabolites, including organic acids, across the biofilm. For decades, measuring pH in dental biofilm has...... been limited to monitoring bulk pH with electrodes. Although pH microelectrodes with a better spatial resolution have been developed, they do not permit to monitor horizontal pH gradients in real-time. Quantitative fluorescent microscopic techniques, such as fluorescence lifetime imaging or pH...... ratiometry, can be employed to map the pH landscape in dental biofilm with more detail. However, when pH sensitive fluorescent probes are used to visualize pH in biofilms, it is crucial to differentiate between extracellular and intracellular pH. Intracellular microbial pH and pH in the extracellular matrix...

  10. Early real-time estimation of the basic reproduction number of emerging or reemerging infectious diseases in a community with heterogeneous contact pattern: Using data from Hong Kong 2009 H1N1 Pandemic Influenza as an illustrative example.

    Directory of Open Access Journals (Sweden)

    Kin On Kwok

    Full Text Available Emerging and re-emerging infections such as SARS (2003 and pandemic H1N1 (2009 have caused concern for public health researchers and policy makers due to the increased burden of these diseases on health care systems. This concern has prompted the use of mathematical models to evaluate strategies to control disease spread, making these models invaluable tools to identify optimal intervention strategies. A particularly important quantity in infectious disease epidemiology is the basic reproduction number, R0. Estimation of this quantity is crucial for effective control responses in the early phase of an epidemic. In our previous study, an approach for estimating the basic reproduction number in real time was developed. This approach uses case notification data and the structure of potential transmission contacts to accurately estimate R0 from the limited amount of information available at the early stage of an outbreak. Based on this approach, we extend the existing methodology; the most recent method features intra- and inter-age groups contact heterogeneity. Given the number of newly reported cases at the early stage of the outbreak, with parsimony assumptions on removal distribution and infectivity profile of the diseases, experiments to estimate real time R0 under different levels of intra- and inter-group contact heterogeneity using two age groups are presented. We show that the new method converges more quickly to the actual value of R0 than the previous one, in particular when there is high-level intra-group and inter-group contact heterogeneity. With the age specific contact patterns, number of newly reported cases, removal distribution, and information about the natural history of the 2009 pandemic influenza in Hong Kong, we also use the extended model to estimate R0 and age-specific R0.

  11. Contact process in a wedge

    CERN Document Server

    Cox, J Theodore; Schinazi, Rinaldo B

    2009-01-01

    We prove that the supercritical one-dimensional contact process survives in certain wedge-like space-time regions, and that when it survives it couples with the unrestricted contact process started from its upper invariant measure. As an application we show that a type of weak coexistence is possible in the nearest-neighbor ``grass-bushes-trees'' successional model introduced in Durrett and Swindle (1991).

  12. Contact Dermatitis in Pediatrics.

    Science.gov (United States)

    Pelletier, Janice L; Perez, Caroline; Jacob, Sharon E

    2016-08-01

    Contact dermatitis is an umbrella term that describes the skin's reaction to contacted noxious or allergenic substances. The two main categories of contact dermatitis are irritant type and allergic type. This review discusses the signs, symptoms, causes, and complications of contact dermatitis. It addresses the testing, treatment, and prevention of contact dermatitis. Proper management of contact dermatitis includes avoidance measures for susceptible children. Implementation of a nickel directive (regulating the use of nickel in jewelry and other products that come into contact with the skin) could further reduce exposure to the most common allergens in the pediatric population. [Pediatr Ann. 2016;45(8):e287-e292.].

  13. The pH induced sol-gel transition in skim milk revisited. A detailed study using time-resolved light and x-ray scattering experiments.

    Science.gov (United States)

    Moitzi, Christian; Menzel, Andreas; Schurtenberger, Peter; Stradner, Anna

    2011-03-15

    We present a detailed study of the evolution of the size, structure and stability of casein micelles upon acidification of skim milk typically applied in yogurt-making processes using a combination of time-resolved light and small-angle X-ray scattering experiments. While most of the available light scattering studies on casein acidification have been restricted to transparent and therefore highly diluted samples, we now profit from a newly developed multiangle 3D light scattering instrument, which allows for time-resolved measurements in highly turbid samples. Our experiments clearly demonstrate the presence of two parallel pH-dependent processes, micellar reassembly and aggregation. Using a systematic investigation of the effect of casein concentration, acidification rate, and ionic strength, we are able to decouple these two processes and obtain detailed information about the pH-induced restructuration of the casein micelle structure that occurs prior to destabilization. Moreover, our experiments also unambiguously demonstrate that these micellar reassembly processes are highly concentration dependent, and that typical light scattering studies conducted under highly diluted conditions are resulting in findings that may not be relevant for the situation encountered in industrial processes at higher concentrations. Experiments conducted with covalently cross-linked micelles, where the pH-induced reassembly has been suppressed, further confirm our findings.

  14. Adhesion in hydrogel contacts

    Science.gov (United States)

    Torres, J. R.; Jay, G. D.; Kim, K.-S.; Bothun, G. D.

    2016-05-01

    A generalized thermomechanical model for adhesion was developed to elucidate the mechanisms of dissipation within the viscoelastic bulk of a hyperelastic hydrogel. Results show that in addition to the expected energy release rate of interface formation, as well as the viscous flow dissipation, the bulk composition exhibits dissipation due to phase inhomogeneity morphological changes. The mixing thermodynamics of the matrix and solvent determines the dynamics of the phase inhomogeneities, which can enhance or disrupt adhesion. The model also accounts for the time-dependent behaviour. A parameter is proposed to discern the dominant dissipation mechanism in hydrogel contact detachment.

  15. PH og modernismen

    DEFF Research Database (Denmark)

    Ahnfeldt-Mollerup, Merete

    2012-01-01

    Artiklen kaster et kritisk blik på Poul Henningsens samfundsanalyse og dennes sammenhæng med hans design. PH ses i en bredere national og international sammenhæng. Diskussion af designmetoder, æstetik og Bauhaus.......Artiklen kaster et kritisk blik på Poul Henningsens samfundsanalyse og dennes sammenhæng med hans design. PH ses i en bredere national og international sammenhæng. Diskussion af designmetoder, æstetik og Bauhaus....

  16. Human serum transferrin: a tale of two lobes. Urea gel and steady state fluorescence analysis of recombinant transferrins as a function of pH, time, and the soluble portion of the transferrin receptor.

    Science.gov (United States)

    Byrne, Shaina L; Mason, Anne B

    2009-06-01

    Iron release from human serum transferrin (hTF) has been studied extensively; however, the molecular details of the mechanism(s) remain incomplete. This is in part due to the complexity of this process, which is influenced by lobe-lobe interactions, the transferrin receptor (TFR), the salt effect, the presence of a chelator, and acidification within the endosome, resulting in iron release. The present work brings together many of the concepts and assertions derived from previous studies in a methodical, uniform, and visual manner. Examination of earlier work reveals some uncertainty due to sample and technical limitations. We have used a combination of steady-state fluorescence and urea gels to evaluate the effect of conformation, pH, time, and the soluble portion of the TFR (sTFR) on iron release from each lobe of hTF. The use of authentic recombinant monoferric and locked species removes any possibility of cross-contamination by acquisition of iron. Elimination of detergent by use of the sTFR provides a further technical advantage. We find that iron release from the N-lobe is very sensitive to the conformation of the C-lobe, but is insensitive to the presence of the sTFR or to changes in pH (between 5.6 and 6.4). Specifically, when the cleft of the C-lobe is locked, the urea gels indicate that only about half of the iron is completely removed from the cleft of the N-lobe. Iron release from the C-lobe is most affected by the presence of the sTFR and changes in pH, but is unaffected by the conformation of the N-lobe. A model for iron release from diferric hTF is provided to delineate our findings.

  17. Fingertip contact influences human postural control

    Science.gov (United States)

    Jeka, J. J.; Lackner, J. R.

    1994-01-01

    Touch and pressure stimulation of the body surface can strongly influence apparent body orientation, as well as the maintenance of upright posture during quiet stance. In the present study, we investigated the relationship between postural sway and contact forces at the fingertip while subjects touched a rigid metal bar. Subjects were tested in the tandem Romberg stance with eyes open or closed under three conditions of fingertip contact: no contact, touch contact (postural sway when compared to the no contact, eyes closed condition. Body sway and fingertip forces were essentially in phase with force contact, suggesting that fingertip contact forces are physically counteracting body sway. Time delays between body sway and fingertip forces were much larger with light touch contact, suggesting that the fingertip is providing information that allows anticipatory innervation of musculature to reduce body sway. The results are related to observations on precision grip as well as the somatosensory, proprioceptive, and motor mechanisms involved in the reduction of body sway.

  18. Performance and model of a novel multi-sparger multi-stage airlift loop membrane bioreactor to treat high-strength 7-ACA pharmaceutical wastewater: effect of hydraulic retention time, temperature and pH.

    Science.gov (United States)

    Chen, Zhao-bo; He, Zhang-wei; Tang, Cong-cong; Hu, Dong-xue; Cui, Yu-bo; Wang, Ai-jie; Zhang, Ying; Yan, Li-long; Ren, Nan-qi

    2014-09-01

    In this study, three novel multi-sparger multi-stage airlift loop membrane bioreactors (Ms(2)ALMBRs) were set up in parallel for treating synthetic high-strength 7-ACA pharmaceutical wastewater under different HRTs, temperatures and pHs, respectively. During the 200-day operating time, average COD removal efficiencies were 94.96%, 96.05% and 93.9%. While average 7-ACA removal efficiencies were 66.44%, 59.04% and 59.60%, respectively. The optimal conditions were 10h, 15-35°C and 7-9 for HRT, temperature and pH, respectively. Moreover, the sludge characteristics and microorganism drug-resistances were explored. Results showed that different temperatures and pHs influenced contaminant removals by affecting MLSS concentration and β-lactamase activity significantly. In addition, mathematical statistical models, built on the polynomial and linear regression techniques, were developed for exploring the inner relationships between HRT, temperature and pH changes and MLSS concentrations, β-lactamase activities and contaminant removals of the Ms(2)ALMBR system.

  19. Fe{sub 2}O{sub 3}-Bi{sub 2}O{sub 3}-B{sub 2}O{sub 3} glasses as lithium-free nonsilicate pH responsive glasses – Compatibility between pH responsivity and hydrophobicity

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Tadanori, E-mail: hasimoto@chem.mie-u.ac.jp [Department of Chemistry for Materials, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-Cho, Tsu, Mie, 514-8507 (Japan); Hamajima, Mitsuaki; Ohta, Honami; Nasu, Hiroyuki; Ishihara, Atsushi [Department of Chemistry for Materials, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-Cho, Tsu, Mie, 514-8507 (Japan); Nishio, Yuji [HORIBA, Ltd., 2 Miyanohigasi, Kisshoin, Minami-Ku, Kyoto, 601-8510 (Japan)

    2014-02-01

    Highlights: • Fe{sub 2}O{sub 3}-rich FeBiB glasses show high pH sensitivity and short pH response time. • Bi{sub 2}O{sub 3}-rich FeBiB glasses show relatively high contact angle for water. • FeBiB glasses are lithium-free nonsilicate pH responsive ones. • pH responsivity and hydrophobicity are obtained for optimum glass compositions. - Abstract: Lithium silicate-based glasses have widely been used as commercially available pH glass electrodes. It was revealed that Ti{sup 3+}-containing titanophosphate (TiO{sub 2}-P{sub 2}O{sub 5}, TP) glasses are pH responsive as lithium-free nonsilicate glasses for the first time. TP glasses with the compatibility between pH responsivity and self-cleaning property were obtained by the sequential post-annealing (oxidation and reduction) of as-prepared glasses. Bi{sub 2}O{sub 3}-B{sub 2}O{sub 3} (BiB) glasses are relatively hydrophobic and are expected to show anti-fouling effect. They are unsuitable for pH responsive glasses, because they have high electrical resistivity. In the present study, xFe{sub 2}O{sub 3}·yBi{sub 2}O{sub 3}·(100 − x − y)B{sub 2}O{sub 3} glasses (xFeyBiB, x = 0–20 mol%, y = 20–80 mol%) glasses were selected as new pH responsive glasses with hydrophobicity, because Fe{sub 2}O{sub 3} is a representative component for causing hopping conduction to the glasses. BiB glass did not show pH responsivity, whereas xFeyBiB glasses showed good pH responsivity. xFeyBiB glasses are lithium-free nonsilicate pH responsive ones as well as TP glasses. The electrical resistivity and pH response time decreased with increasing Fe{sub 2}O{sub 3} content. The pH repeatability for standard solutions increased with increasing Bi{sub 2}O{sub 3} content. Silicate glass (20Fe70BiSi) showed better pH responsivity but lower contact angle than those of borate glass (20Fe70BiB). pH sensitivity increased in order of TP glasses (about 80%), xFeyBiB glasses (about 90%) and commercial pH responsive glass (about 100%). x

  20. Effect of soy and bovine milks on the dental plaque pH

    Directory of Open Access Journals (Sweden)

    Peyvand Moeiny

    2016-11-01

    (P<0.05. Conclusion: Bovine milk in none of frequent timing dropped its pH below basic pH but also significantly increased the plaque pH above the critical pH. The maximum pH drop for soy milk was in 2minutes after consumption but it never reached below the critical pH.

  1. Contact Angle Goniometer

    Data.gov (United States)

    Federal Laboratory Consortium — Description:The FTA32 goniometer provides video-based contact angle and surface tension measurement. Contact angles are measured by fitting a mathematical expression...

  2. Corporate Consumer Contact API

    Data.gov (United States)

    General Services Administration — The data in the Corporate Consumer Contact API is based on the content you can find in the Corporate Consumer Contact listing in the Consumer Action Handbook (PDF)....

  3. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... lenses without a prescription in the United States. All contact lenses are medical devices that require a ... no such thing as a "one size fits all" contact lens. Lenses that are not properly fitted ...

  4. Dermatitis, contact (image)

    Science.gov (United States)

    This picture shows a skin inflammation (dermatitis) caused by contact with a material that causes an allergic reaction in this person. Contact dermatitis is a relatively common condition, and can be caused ...

  5. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her ...

  6. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Contact Lenses Without a Prescription Sep. 26, 2013 It started as an impulsive buy from a souvenir ... Can Ruin Vision Eye Makeup Safety In fact, it is illegal to sell colored contact lenses without ...

  7. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ...

  8. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... glow-in-the-dark lizard lenses, costume contacts can certainly add a spooky, eye-popping touch. But ... consideration as a standard contact lens because they can be purchased over-the-counter or on the ...

  9. Contact Us about Asbestos

    Science.gov (United States)

    How to contact EPA for more information on asbestos, including state and regional contacts, EPA’s Asbestos Abatement/Management Ombudsman and the Toxic Substances Control Act (TSCA) Assistance Information Service (TSCA Hotline).

  10. Contact lens in keratoconus

    OpenAIRE

    Varsha M Rathi; Preeji S Mandathara; Srikanth Dumpati

    2013-01-01

    Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the En...

  11. Coral contact dermatitis

    OpenAIRE

    Jefferson, Julie; Thompson, Curtis; Hinshaw, Molly; Rich, Phoebe

    2015-01-01

    Corals can elicit both toxic and allergic reactions upon contact with the skin. Clinical presentations vary depending on whether the reaction is acute, delayed, or chronic. Literature concerning cutaneous reactions to corals and other Cnidarians is scarce. Herein we report a case of delayed contact hypersensitivity reaction to coral and review the clinical and histopathological features of coral contact dermatitis.

  12. Coral contact dermatitis.

    Science.gov (United States)

    Jefferson, Julie; Thompson, Curtis; Hinshaw, Molly; Rich, Phoebe

    2015-04-16

    Corals can elicit both toxic and allergic reactions upon contact with the skin. Clinical presentations vary depending on whether the reaction is acute, delayed, or chronic. Literature concerning cutaneous reactions to corals and other Cnidarians is scarce. Herein we report a case of delayed contact hypersensitivity reaction to coral and review the clinical and histopathological features of coral contact dermatitis.

  13. Contact urticaria : Present scenario

    Directory of Open Access Journals (Sweden)

    Bhatia Ruchi

    2009-01-01

    Full Text Available Immunological contact urticaria is a hypersensitivity reaction that appears on the skin following contact with an eliciting substance. Recent advances in our understanding of the molecular mechanism and pathogenesis of this reaction have altered its classification, diagnosis, and treatment. We discuss classification, epidemiology, diagnosis, testing, and treatment options that are available to patients with contact urticaria.

  14. Types of Contact Lenses

    Science.gov (United States)

    ... back to top ] Rigid Gas Permeable (RGP) Contact Lenses Rigid gas permeable contact lenses (RGPs) are more durable ... Ortho-K) Orthokeratology, or Ortho-K, is a lens fitting procedure that uses specially designed rigid gas permeable (RGP) contact lenses to change the ...

  15. Mixed lubricated line contacts

    OpenAIRE

    Faraon, Irinel Cosmin

    2005-01-01

    The present work deals with friction in mixed lubricated line contacts. Components in systems are becoming smaller and due to, for instance power transmitted, partial contact may occur. In industrial applications, friction between the moving contacting surfaces cannot be avoided, therefore it is essential that an engineer is able to predict friction.

  16. New Cosmetic Contact Allergens

    Directory of Open Access Journals (Sweden)

    An Goossens

    2015-02-01

    Full Text Available Allergic and photo-allergic contact dermatitis, and immunologic contact urticaria are potential immune-mediated adverse effects from cosmetics. Fragrance components and preservatives are certainly the most frequently observed allergens; however, all ingredients must be considered when investigating for contact allergy.

  17. Quantum Transport with Three Time Dependent Quantum Point Contacts%含三个含时点接触的量子输运

    Institute of Scientific and Technical Information of China (English)

    程芳

    2016-01-01

    拓扑绝缘体的材料可大大提高计算机芯片的运行速度和工作效率,甚至可能会成为以自旋电子学为基础的下一代全新计算机技术的基石。拓扑绝缘体的边缘态展现出奇特的性质,电子在表面自由流动,不损耗任何能量。使用玻色化,重整化群,格林函数的方法从理论上研究了三个含时点接触存在对拓扑边缘态输运性质的影响。得到电流随偏压和温度变化的解析表达式,以及依赖于电子间相互作用幂指数变化规律。该理论提供了一种调控纳米结构中输运性质的手段。%The novel topological insulator material has provided the physical foundation for the dissipationless spin transport, possibly constructed the brand-new spintronic devices. The edge state of the topological insulator shows unusual helical feature due to the electron spin-momentum locking. Using the Luttinger liquid theory and nonequilibium Green function, the quantum transport in a quantum spin Hall bar with three quantum point contacts ( QPCs) was studied. The currents display very different pump frequency dependence for weak and strong e-e inter-action. These unique properties were induced by the helical feature of the edge states, and therefore can be used to detect and control edge state transport.

  18. Contact lens in keratoconus

    Directory of Open Access Journals (Sweden)

    Varsha M Rathi

    2013-01-01

    Full Text Available Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP lenses, soft and soft toric lenses, piggy back contact lenses (PBCL, hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL.

  19. Client Contact versus Paperwork: A Student Perspective.

    Science.gov (United States)

    Strohmer, Douglas C.; And Others

    1979-01-01

    Surveys master's level rehabilitation counseling students and examines percentage of time students spend involved in client contact and paperwork during their internship. Time spent in client contact was nearly double that spent doing paperwork for this group. Data from a number of settings are discussed. (Author)

  20. pH Basics

    Science.gov (United States)

    Lunelli, Bruno; Scagnolari, Francesco

    2009-01-01

    The exposition of the pervasive concept of pH, of its foundations and implementation as a meaningful quantitative measurement, in nonspecialist university texts is often not easy to follow because too many of its theoretical and operative underpinnings are neglected. To help the inquiring student we provide a concise introduction to the depth just…

  1. Modeling Thermal Contact Resistance

    Science.gov (United States)

    Kittel, Peter; Sperans, Joel (Technical Monitor)

    1994-01-01

    One difficulty in using cryocoolers is making good thermal contact between the cooler and the instrument being cooled. The connection is often made through a bolted joint. The temperature drop associated with this joint has been the subject of many experimental and theoretical studies. The low temperature behavior of dry joints have shown some anomalous dependence on the surface condition of the mating parts. There is also some doubts on how well one can extrapolate from the test samples to predicting the performance of a real system. Both finite element and analytic models of a simple contact system have been developed. The model assumes (a) the contact is dry (contact limited to a small portion of the total available area and the spaces in-between the actual contact patches are perfect insulators), (b) contacts are clean (conductivity of the actual contact is the same as the bulk), (c) small temperature gradients (the bulk conductance may be assumed to be temperature independent), (d) the absolute temperature is low (thermal radiation effects are ignored), and (e) the dimensions of the nominal contact area are small compared to the thickness of the bulk material (the contact effects are localized near the contact). The models show that in the limit of actual contact area much less than the nominal area (a much less than A), that the excess temperature drop due to a single point of contact scales as a(exp -1/2). This disturbance only extends a distance approx. A(exp 1/2) into the bulk material. A group of identical contacts will result in an excess temperature drop that scales as n(exp -1/2), where n is the number of contacts and n dot a is constant. This implies that flat rough surfaces will have a lower excess temperature drop than flat polished surfaces.

  2. Improvement of GaN light-emitting diodes with surface-treated Al-doped ZnO transparent Ohmic contacts by holographic photonic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Yang, W.F. [Xiamen University, Department of Physics, Xiamen (China); National University of Singapore, Department of Materials Science and Engineering, Singapore (Singapore); Liu, Z.G.; Xie, Y.N.; Cai, J.F.; Liu, S.; Wu, Z.Y. [Xiamen University, Department of Physics, Xiamen (China); Gong, H. [National University of Singapore, Department of Materials Science and Engineering, Singapore (Singapore)

    2012-06-15

    This letter presents a holographic photonic crystal (H-PhC) Al-doped ZnO (AZO) transparent Ohmic contact layer on p-GaN to increase the light output of GaN-based LEDs without destroying the p-GaN. The operating voltage of the PhC LEDs at 20 mA was almost the same as that of the typical planar AZO LEDs. While the resultant PhC LED devices exhibited significant improvements in light extraction, up to 1.22 times that of planar AZO LEDs without PhC integration. Temperature dependence of the integrated photoluminescence intensity indicates that this improvement can be attributed to the increased extraction efficiency due to the surface modification. These results demonstrate that the surface-treated AZO layer by H-PhCs is suitable for fabricating high-brightness GaN-based LEDs. (orig.)

  3. The effect of pH modification on wetting kinetics of a naturally water repellent coniferous soil

    Science.gov (United States)

    Amer, Ahmad; Diehl, Dörte; Schaumann, Gabriele

    2017-04-01

    The interfacial dynamics of soil-water interactions are significantly affected by the hydrophobic properties of organic matter. The underlying mechanisms responsible for the development of soil water repellency (SWR) are still under discussion. Various environmental factors control the appearance and degree of SWR. The wetting of soil greatly depends on the physicochemical characteristics of soil surfaces which in turn depends on pH. In this contribution, we propose a mechanism for the change in SWR that is observed upon the artificial change in soil pH. Wetting kinetics were studied by the time dependent sessile drop measurements (TISED) of the contact angle, the work of spreading and the drop base diameter as time elapsed under controlled relative humidity. Modification of pH strongly affected the wetting kinetics, suggesting maximum wetting resistance at the control pH (3.60) and with decreased wetting resistance as pH was changed in either direction. The enhancement of the wetting kinetics by artificial modification of soil pH can be attributed to the chemical modification in organic materials coating soil particles based on the magnitude of spreading activation energy and the hydrophilic/hydrophobic moieties ratio of treated soil samples measured by (XPS & MIR spectroscopy). On the basis of our current state of knowledge, we propose that acid and base catalyzed hydrolysis-condensation reactions as dominant processes responsible for the chemical nature of SWR.

  4. Coupled Chemical and Thermal Processes During Contact Metamorphism: Constraining Rates and Duration with Time-Dependent 3-D Heat and Mass Transport Modeling of Fluid-Rock Systems

    Science.gov (United States)

    Dutrow, B. L.; Henry, D.; Gable, C. W.; Heydari, E.; Travis, B. J.

    2016-12-01

    Hydrothermal, metamorphic and metasomatic rocks develop through a complex set of coupled thermal, chemical and mechanical processes that contain non-linear feedbacks. The integrated outcome results in a mineral assemblage with a specific texture that records the rates, magnitude and duration of the controlling processes. However, it is often difficult to extract this coupled information from the rock record due to the competing and time-integrated nature of the final product. A particularly problematic case arises when advective metasomatism accompanies thermal energy transport. Advective transport of reactive components by thermally driven flowing fluids can dramatically alter the original bulk rock chemistry. In some instances, these chemical transformations are slow but in others, these alterations can occur over short time scales (yrs). To facilitate investigations of coupled, complex systems and to constrain the rates, duration and relative importance of governing processes during a thermal event, high-resolution 3-D time dependent computational modeling is used. An example of the integrated effects of thermal and chemical transport is found in subsurface Louisiana. Here, an 11m alkali igneous dike intruded Late Jurassic sandy limestones transforming these into new mineral assemblages rich in alkali, alkaline earth elements and F; hydrogrossular, diopside, pectolite (pct), apophyllite, fluorite, and feldspars. Increased temperatures (Ts) and significant mass transport of components from the dike into the host rocks are required. A series of coupled heat and mass transport calculations constrain the rates and duration of the thermal pulse and provide insights into the time-scale of mass transport within this system. For example, calculations incorporating silica transport indicate that at the pct zone (1.5m), thermal conditions remained above 150oC for 2.8 yrs assuming anisotropic permeability (K) and 4.2 yrs (layered K) reaching Tmax at 0.36 (aniso) or 0.53 yr

  5. Improvements To Micro Contact Performance And Reliability

    Science.gov (United States)

    2016-12-22

    Wafer Purpose Masks Process Print Date Wafer ID µ-contacts Anchor/ Bump Anchor & Bump 8/16/2016 Init. Process... Wafer Purpose Masks Process Print Date Wafer ID µ-contacts Anchor/ Bump Anchor & Bump 8/16/2016 Init. Process Step Notes Date Time Process...B _______________ Wafer Purpose Masks Process Print Date Wafer ID µ-contacts Anchor/ Bump Anchor & Bump 8/16/2016 Init. Process

  6. Highly Sensitive and Wide-Dynamic-Range Multichannel Optical-Fiber pH Sensor Based on PWM Technique

    Directory of Open Access Journals (Sweden)

    Md. Rajibur Rahaman Khan

    2016-11-01

    Full Text Available In this study, we propose a highly sensitive multichannel pH sensor that is based on an optical-fiber pulse width modulation (PWM technique. According to the optical-fiber PWM method, the received sensing signal’s pulse width changes when the optical-fiber pH sensing-element of the array comes into contact with pH buffer solutions. The proposed optical-fiber PWM pH-sensing system offers a linear sensing response over a wide range of pH values from 2 to 12, with a high pH-sensing ability. The sensitivity of the proposed pH sensor is 0.46 µs/pH, and the correlation coefficient R2 is approximately 0.997. Additional advantages of the proposed optical-fiber PWM pH sensor include a short/fast response-time of about 8 s, good reproducibility properties with a relative standard deviation (RSD of about 0.019, easy fabrication, low cost, small size, reusability of the optical-fiber sensing-element, and the capability of remote sensing. Finally, the performance of the proposed PWM pH sensor was compared with that of potentiometric, optical-fiber modal interferometer, and optical-fiber Fabry–Perot interferometer pH sensors with respect to dynamic range width, linearity as well as response and recovery times. We observed that the proposed sensing systems have better sensing abilities than the above-mentioned pH sensors.

  7. Contact angle hysteresis explained.

    Science.gov (United States)

    Gao, Lichao; McCarthy, Thomas J

    2006-07-04

    A view of contact angle hysteresis from the perspectives of the three-phase contact line and of the kinetics of contact line motion is given. Arguments are made that advancing and receding are discrete events that have different activation energies. That hysteresis can be quantified as an activation energy by the changes in interfacial area is argued. That this is an appropriate way of viewing hysteresis is demonstrated with examples.

  8. Introduction to contact mechanics

    CERN Document Server

    Fischer-Cripps, Anthony C

    2000-01-01

    Contact mechanics deals with the elastic or plastic contact between two solid objects, and is thus intimately connected with such topics as fracture, hardness, and elasticity.This text, intended for advanced undergraduates, begins with an introduction to the mechanical properties of materials, general fracture mechanics, and fractures in brittle solids.This is followed by a detailed discussion of stresses and the nature of elastic and elastic-plastic contact.

  9. Non-contact test set-up for aeroelasticity in a rotating turbomachine combining a novel acoustic excitation system with tip-timing

    Science.gov (United States)

    Freund, O.; Montgomery, M.; Mittelbach, M.; Seume, J. R.

    2014-03-01

    Due to trends in aero-design, aeroelasticity becomes increasingly important in modern turbomachines. Design requirements of turbomachines lead to the development of high aspect ratio blades and blade integral disc designs (blisks), which are especially prone to complex modes of vibration. Therefore, experimental investigations yielding high quality data are required for improving the understanding of aeroelastic effects in turbomachines. One possibility to achieve high quality data is to excite and measure blade vibrations in turbomachines. The major requirement for blade excitation and blade vibration measurements is to minimize interference with the aeroelastic effects to be investigated. Thus in this paper, a non-contact—and thus low interference—experimental set-up for exciting and measuring blade vibrations is proposed and shown to work. A novel acoustic system excites rotor blade vibrations, which are measured with an optical tip-timing system. By performing measurements in an axial compressor, the potential of the acoustic excitation method for investigating aeroelastic effects is explored. The basic principle of this method is described and proven through the analysis of blade responses at different acoustic excitation frequencies and at different rotational speeds. To verify the accuracy of the tip-timing system, amplitudes measured by tip-timing are compared with strain gage measurements. They are found to agree well. Two approaches to vary the nodal diameter (ND) of the excited vibration mode by controlling the acoustic excitation are presented. By combining the different excitable acoustic modes with a phase-lag control, each ND of the investigated 30 blade rotor can be excited individually. This feature of the present acoustic excitation system is of great benefit to aeroelastic investigations and represents one of the main advantages over other excitation methods proposed in the past. In future studies, the acoustic excitation method will be used

  10. Allergic Contact Dermatitis

    Directory of Open Access Journals (Sweden)

    Meltem Önder

    2009-03-01

    Full Text Available Allergic contact dermatitis is the delayed type hypersensitivity reaction to exogenous agents. Allergic contact dermatitis may clinically present acutely after allergen exposure and initial sensitization in a previously sensitized individual. Acute phase is characterized by erythematous, scaly plaques. In severe cases vesiculation and bullae in exposed areas are very characteristic. Repeated or continuous exposure of sensitized individual with allergen result in chronic dermatitis. Lichenification, erythematous plaques, hyperkeratosis and fissuring may develop in chronic patients. Allergic contact dermatitis is very common dermatologic problem in dermatology daily practice. A diagnosis of contact dermatitis requires the careful consideration of patient history, physical examination and patch testing. The knowledge of the clinical features of the skin reactions to various contactans is important to make a correct diagnosis of contact dermatitis. It can be seen in every age, in children textile product, accessories and touch products are common allergens, while in adults allergic contact dermatitis may be related with topical medicaments. The contact pattern of contact dermatitis depends on fashion and local traditions as well. The localization of allergic reaction should be evaluated and patients’ occupation and hobbies should be asked. The purpose of this review is to introduce to our collaques up dated allergic contact dermatitis literatures both in Turkey and in the World.

  11. Contact Quality in Participation

    DEFF Research Database (Denmark)

    Simonsen, Jesper; Jensen, Olav Storm

    2016-01-01

    We investigate the concept of participation from the perspective of quality of the contact in the communicative interactions between participants. We argue for the need for an academic-personal competence that qualifies the human contact central in all Participatory Design (PD) activities as a way...... to contribute to “an era of participation.” We describe a contact perspective in PD developed through a collaboration with body-oriented psychotherapeutic research that have specialized experiences in investigating open-minded contact and authentic meetings as body-related experiences....

  12. Colors and contact dermatitis.

    Science.gov (United States)

    Bonamonte, Domenico; Foti, Caterina; Romita, Paolo; Vestita, Michelangelo; Angelini, Gianni

    2014-01-01

    The diagnosis of skin diseases relies on several clinical signs, among which color is of paramount importance. In this review, we consider certain clinical presentations of both eczematous and noneczematous contact dermatitis in which color plays a peculiar role orientating toward the right diagnosis. The conditions that will be discussed include specific clinical-morphologic subtypes of eczematous contact dermatitis, primary melanocytic, and nonmelanocytic contact hyperchromia, black dermographism, contact chemical leukoderma, and others. Based on the physical, chemical, and biologic factors underlying a healthy skin color, the various skin shades drawing a disease picture are thoroughly debated, stressing their etiopathogenic origins and histopathologic aspects.

  13. Study on the Rumen VFA and pH with the Time Changing in Cows under the Condition of TMR Feeding%TMR饲养条件下奶牛瘤胃VFA、pH变化规律的研究

    Institute of Scientific and Technical Information of China (English)

    盛东峰; 武安泉

    2012-01-01

    为探究全混合日粮(TMR)饲养条件下奶牛瘤胃发酵参数的变化规律,以3头装有永久性瘤胃瘘管的中国荷斯坦奶牛为试验动物,采用TMR饲养,测定了瘤胃24h挥发性脂肪酸(VFA)浓度及pH值.结果表明:在TMR条件下,试验奶牛瘤胃液pH值的变化范围为5.86~6.51,各时间点之间差异不显著(P>0.05);乙酸浓度、丙酸浓度、丁酸浓度变动范围分别为69.62~85.71mmol/L、19.33~25.91mmol/L、10.44~14.02mmol/L,且3种VFA出现最高浓度和最低浓度的时间点均为20:00和08:00;乙酸/丙酸值的变动范围为3.31~3.61,且在20.00比值最小,在8:00比值最大.综合分析显示,TMR技术有利于奶牛瘤胃丙酸型发酵,提高生产效益.%A total of three China Hostain cow fitted with ruminal fistula were used to determine the vary law in 24 h of the ruminal internal environment parameters under the Total Mixed Ration (TMR) technology. The results showed that the rumen pH value changed over time and the aver-age pH was 5. 86-6. 51 but no significant changes were observed at each time point. The average concentration of acetic acid,third acid and butyric acid was 69. 62-85. 71 mrnol/L, 19. 33 - 25. 91 mmol/L and 10. 44-14. 02 mmol/L, respectively. The maximum and lowest concentrations of three VFA appeared at 20:00 and 08:00. The average of acetic acid/propionic acid varied from 3.31 to 3. 61, with the minimum and maximum levels appearing at 20; 00 and 8; 00 respectively. Comprehensive analysis showed that the TMR technology was conductive to rumen propionic acid type fermentation to improve production efficiency of cow.

  14. 17-4 PH and 15-5 PH

    Science.gov (United States)

    Johnson, Howard T.

    1995-01-01

    17-4 PH and 15-5 PH are extremely useful and versatile precipitation-hardening stainless steels. Armco 17-4 PH is well suited for the magnetic particle inspection requirements of Aerospace Material Specification. Armco 15-5 PH and 17-4 PH are produced in billet, plate, bar, and wire. Also, 15-5 PH is able to meet the stringent mechanical properties required in the aerospace and nuclear industries. Both products are easy to heat treat and machine, making them very useful in many applications.

  15. Sutures and contact homology I

    CERN Document Server

    Colin, Vincent; Honda, Ko; Hutchings, Michael

    2010-01-01

    We define a relative version of contact homology for contact manifolds with convex boundary, and prove basic properties of this relative contact homology. Similar considerations also hold for embedded contact homology.

  16. An Optical Sensor with Polyaniline-Gold Hybrid Nanostructures for Monitoring pH in Saliva

    Directory of Open Access Journals (Sweden)

    Chongdai Luo

    2017-03-01

    Full Text Available Saliva contains important personal physiological information that is related to some diseases, and it is a valuable source of biochemical information that can be collected rapidly, frequently, and without stress. In this article, we reported a new and simple localized surface plasmon resonance (LSPR substrate composed of polyaniline (PANI-gold hybrid nanostructures as an optical sensor for monitoring the pH of saliva samples. The overall appearance and topography of the substrates, the composition, and the wettability of the LSPR surfaces were characterized by optical and scanning electron microscope (SEM images, infrared spectra, and contact angles measurement, respectively. The PANI-gold hybrid substrate readily responded to the pH. The response time was very short, which was 3.5 s when the pH switched from 2 to 7, and 4.5 s from 7 to 2. The changes of visible-near-infrared (NIR spectra of this sensor upon varying pH in solution showed that—for the absorption at given wavelengths of 665 nm and 785 nm—the sensitivities were 0.0299 a.u./pH (a.u. = arbitrary unit with a linear range of pH = 5–8 and 0.0234 a.u./pH with linear range of pH = 2–8, respectively. By using this new sensor, the pH of a real saliva sample was monitored and was consistent with the parallel measurements with a standard laboratory method. The results suggest that this novel LSPR sensor shows great potential in the field of mobile healthcare and home medical devices, and could also be modified by different sensitive materials to detect various molecules or ions in the future.

  17. A Model for Contact Binary Systems

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A model for contact binary systems is presented, which incorporates the following special features: a) The energy exchange between the components is based on the understanding that the energy exchange is due to the release of potential, kinetic and thermal energies of the exchanged mass. b) A special form of mass and angular momentum loss occurring in contact binaries is losses via the outer Lagrangian point. c) The effects of spin, orbital rotation and tidal action on the stellar structure as well as the effect of meridian circulation on the mixing of the chemical elements are considered. d) The model is valid not only for low-mass contact binaries but also for high-mass contact binaries. For illustration, we used the model to trace the evolution of a massive binary system consisting of one 12M⊙ and one 5M⊙ star. The result shows that the start and end of the contact stage fall within the semi-detached phase during which the primary continually transfers mass to the secondary. The time span of the contact stage is short and the mass transfer rate is very large. Therefore, the contact stage can be regarded as a special part of the semi-detached phase with a large mass transfer rate. Both mass loss through the outer Lagrangian point and oscillation between contact and semi-contact states can occur during the contact phase, and the effective temperatures of the primary and the secondary are almost equal.

  18. Time-dependent Wave Packet Quantum Scattering Study of Reaction S(3p)+H2→HS+H on a New ab initio Potential Energy Surface 3A'

    Institute of Scientific and Technical Information of China (English)

    Shuang-jiang Lv; Pei-yu Zhang; Guo-zhong He

    2012-01-01

    A new potential energy surface is presented for the triplet state 3A' of the chemical reaction S(3P)+H2 from a set of accurate ab initio data.The single point energies are computed using highly correlated complete active space self-consistent-field and multi-reference configuration interaction wave functions with a basis set of aug-cc-pV5Z.We have fitted the full set of energy values using many-body expansion method with an Aguado-Paniagua function.Based on the new potential energy surface,we carry out the time-dependent wave packet scattering calculations over the collision energy range of 0.8-2.2 eV.Both the centrifugalsudden approximation and Coriolis Coupling cross sections are obtained.In addition,the total reaction probabilities are calculated for the reactant H2 initially in the vibrational states v=0-3 (j=0).It is found that initial vibrational excitation enhances the title reaction.

  19. Screw bondgraph contact dynamics

    NARCIS (Netherlands)

    Visser, Martijn; Stramigioli, Stefano; Heemskerk, Cock

    2002-01-01

    This paper presents an elegant contact dynamics model in screw bondgraph form. It can model the contact between any two objects of finite curvature. It does so by defining a Gauss frame on the surfaces of both objects in the points that are closest to each other. Then it describes how the Gauss fram

  20. Contact dermatitis. A review

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Benezra, C; Burrows, D;

    1987-01-01

    In recent years, there has been a dramatic rise in our understanding of contact dermatitis. This paper is a review of our knowledge of the mechanisms involved in contact dermatitis and related phenomena, the investigation of these events and the emergence of significant new allergens during...

  1. Allergic Contact Dermatitis

    OpenAIRE

    Meltem Önder

    2009-01-01

    Allergic contact dermatitis is the delayed type hypersensitivity reaction to exogenous agents. Allergic contact dermatitis may clinically present acutely after allergen exposure and initial sensitization in a previously sensitized individual. Acute phase is characterized by erythematous, scaly plaques. In severe cases vesiculation and bullae in exposed areas are very characteristic. Repeated or continuous exposure of sensitized individual with allergen result in chronic dermatitis. Lichenific...

  2. Critical Points of Contact

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Morelli, Nicola

    2011-01-01

    where the networks meet and establish contact. Thus we argue for the usefulness of the notion of Critical Point of Contact (CPC) to deepen our understanding of the actual life within networks. En route to this notion we draw upon theories within as diverse realms such as interaction design, service...

  3. Contact Hamiltonian mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Bravetti, Alessandro, E-mail: alessandro.bravetti@iimas.unam.mx [Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, A. P. 70543, México, DF 04510 (Mexico); Cruz, Hans, E-mail: hans@ciencias.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, A. P. 70543, México, DF 04510 (Mexico); Tapias, Diego, E-mail: diego.tapias@nucleares.unam.mx [Facultad de Ciencias, Universidad Nacional Autónoma de México, A.P. 70543, México, DF 04510 (Mexico)

    2017-01-15

    In this work we introduce contact Hamiltonian mechanics, an extension of symplectic Hamiltonian mechanics, and show that it is a natural candidate for a geometric description of non-dissipative and dissipative systems. For this purpose we review in detail the major features of standard symplectic Hamiltonian dynamics and show that all of them can be generalized to the contact case.

  4. Six-Channel Spectrophotometers (PH) Onboard JEM-GLIMS

    Science.gov (United States)

    Sato, Mitsuteru; Takahashi, Yukihiro; Suzuki, Makoto; Yamazaki, Atsushi; Ushio, Tomoo

    Six-channel spectrophotometers (PH) are the science instruments of JEM-GLIMS to measure absolute intensity of the emission originated from lightning discharges and upper atmospheric transient luminous events (TLEs). PH unit-1 (PH-U1) consists of four spectrophotometer channels named from PH1 to PH4, while PH unit-2 (PH-U2) two spectrophotometer channels named PH5 and PH6. Optical filters of these spectrophotometers are selected to detect TLE emission lines of N2 1PG, N2 2PG, N2+ 1NG, and N2 LBH. Since the bandwidth of the optical filter of PH2, 3, 5, and 6 is 10 nm and since PH1 measures NUV emission, photomultiplier tubes with high-voltage converters are used as a photon detector. To the contrary, PH4 uses a photodiode as a photon detector because the pass-band of the optical filter is enough wide to detect transient optical emission. Though PH does not equip spatial resolution, it can acquire light curve data with a high time resolution of 50 μs with a 12-bit resolution. Thus, the combinational analysis of PH data and Lightning and Sprite Imager (LSI) data, it is possible to clarify the relationship between TLEs and their parent lightning discharges, the occurrence condition of TLEs, and the energy of the electrons which excite TLE emission.

  5. pH matters

    DEFF Research Database (Denmark)

    Inaba, Masanori; Quinson, Jonathan; Arenz, Matthias

    2017-01-01

    We investigated the influence of the ink properties of proton exchange membrane fuel cell (PEMFC) catalysts on the oxygen reduction reaction (ORR) activity determined in thin film rotating disk electrode (TF-RDE) measurements. It was found that the adaption of a previously reported ink recipe...... to home-made catalysts does not lead to satisfying results, although reported work could be reproduced using commercial catalyst samples. It is demonstrated that the pH of the catalyst ink, which has not been addressed in previous TF-RDE studies, is an important parameter that needs to be carefully...

  6. Effect of Notched Strings on Tennis Racket Spin Performance: Ultrahigh-Speed Video Analysis of Spin Rate, Contact Time, and Post-Impact Ball Velocity

    Science.gov (United States)

    Kawazoe, Yoshihiko; Takeda, Yukihiro; Nakagawa, Masamichi

    While some tennis racket strings have more grip than others do, this does not guarantee that they will impart more spin to a tennis ball. Experiments with hand-held rackets are required to determine the longstanding question of how players can discern that different strings behave differently when laboratory tests indicate that they should play the same. In a previous study, we clarified the top-spin mechanism of a tennis racket by using high-speed video analysis on a tennis court for the first time. Furthermore, we improved it by using lubricated notched nylon strings. These experiments revealed that the more the main strings stretch and bend laterally, the more spin is imparted to the ball. This is due to the restoring force being parallel to the string face when the main strings spring back and the ball is released from the strings. Notched strings reduce the spin rate, but this can be effectively counteracted by employing lubricants. Furthermore, we found that imparting more spin reduces shock vibrations on the wrist during impact. The present study revealed that a ball has a 40% lower spin rate when hit with a racket with notched strings than with one with unnotched strings in the case of nylon (it had to be determined whether new strings or lubricated used strings give more spin). The experiments also showed that 30% more spin is imparted to a ball when the string intersections are lubricated by oil than when notched used nylon strings are used. Furthermore, we found that used natural gut notched strings reduced the spin rate by 70% compared to when new natural gut unnotched strings are used. We also investigated different top-spin behaviors obtained when professional and amateur tennis players hit a ball.

  7. Contact patterns among high school students

    CERN Document Server

    Fournet, Julie

    2014-01-01

    Face-to-face contacts between individuals contribute to shape social networks and play an important role in determining how infectious diseases can spread within a population. It is thus important to obtain accurate and reliable descriptions of human contact patterns occurring in various day-to-day life contexts. Recent technological advances and the development of wearable sensors able to sense proximity patterns have made it possible to gather data giving access to time-varying contact networks of individuals in specific environments. Here we present and analyze two such data sets describing with high temporal resolution the contact patterns of students in a high school. We define contact matrices describing the contact patterns between students of different classes and show the importance of the class structure. We take advantage of the fact that the two data sets were collected in the same setting during several days in two successive years to perform a longitudinal analysis on two very different timescal...

  8. Contact materials for nanoelectronics

    KAUST Repository

    Alshareef, Husam N.

    2011-02-01

    In this article, we review current research activities in contact material development for electronic and nanoelectronic devices. A fundamental issue in contact materials research is to understand and control interfacial reactions and phenomena that modify the expected device performance. These reactions have become more challenging and more difficult to control as new materials have been introduced and as device sizes have entered the deep nanoscale. To provide an overview of this field of inquiry, this issue of MRS Bulletin includes articles on gate and contact materials for Si-based devices, junction contact materials for Si-based devices, and contact materials for alternate channel substrates (Ge and III-V), nanodevices. © 2011 Materials Research Society.

  9. 基于时间序列分析的雾滴叶面动态接触角预测与建模%Dynamic Contact Angle Forecasting and Modeling for Drop-Leaf Interface Based on Time Series Analysis

    Institute of Scientific and Technical Information of China (English)

    陆军; 张红涛; 魏德云; 胡玉霞

    2013-01-01

    A prediction and modeling method for dynamic contact angle of spraying agricultural drop on cucumber leaf surface based on image data collected was presented with combination of time series analysis and applying spatial trends theory. The dynamic contact angle 9 of different mass fraction of glyphosate additives (EF8108-B) aqueous solution range from 16.08% to 82. 14% on the cucumber leaf surface were measured by applying high-speed digital camera technology. Experimental results showed that the contact angle declined rapidly within the first 2 s, and then decreased slowly and gradually to reach its stabilized in the following 8 s. The contact angle didn ' t show increase of a downward trend with increasing EF8108 - B solution concentration. The self-relevant and self-regress ion model (AR(2) ) , the mobile average model (MA(3) ) and exponential smoothing model (ES(6) ) were established according to time series analysis, respectively. Moreover, the spatial distribution of spreading diameter, drop height, drop area and drop volume were simulated by applying trend surface theory, then the 3-D dynamic contact angle trend surface model were constructed. The numerical simulation and experimental verification results indicated that the goodness of fit was up to 94. 72% .%提出了一种基于图像数据采集的时间序列分析与空间趋势面相结合的雾滴叶面动态接触角预测和建模方法.利用CCD数字摄像技术,测定了质量分数为16.08% ~82.14%的8种草甘膦助剂(EF8108-B)水溶液液滴在黄瓜叶面上的动态接触角θ.实验结果表明,接触角在0~2s内急剧下降,2~10s内下降平缓并渐趋于稳定;各质量分数EF8108-B液滴在黄瓜叶面的接触角没有随着质量分数的增大呈现接触角降幅增加的趋势.采用时间序列分析建立了黄瓜叶片界面2 s内液滴的动态接触角二阶自回归模型AR(2)、动态液滴尺寸滑动平均模型MA(3)以及动态液

  10. Allergic contact dermatitis.

    Science.gov (United States)

    Becker, Detlef

    2013-07-01

    Allergic contact dermatitis is a frequent inflammatory skin disease. The suspected diagnosis is based on clinical symptoms, a plausible contact to allergens and a suitable history of dermatitis. Differential diagnoses should be considered only after careful exclusion of any causal contact sensitization. Hence, careful diagnosis by patch testing is of great importance. Modifications of the standardized test procedure are the strip patch test and the repeated open application test. The interpretation of the SLS (sodium lauryl sulfate) patch test as well as testing with the patients' own products and working materials are potential sources of error. Accurate patch test reading is affected in particular by the experience and individual factors of the examiner. Therefore, a high degree of standardization and continuous quality control is necessary and may be supported by use of an online patch test reading course made available by the German Contact Dermatitis Research Group. A critical relevance assessment of allergic patch test reactions helps to avoid relapses and the consideration of differential diagnoses. Any allergic test reaction should be documented in an allergy ID card including the INCI name, if appropriate. The diagnostics of allergic contact dermatitis is endangered by a seriously reduced financing of patch testing by the German statutory health insurances. Restrictive regulations by the German Drug Law block the approval of new contact allergens for routine patch testing. Beside the consistent avoidance of allergen contact, temporary use of systemic and topical corticosteroids is the therapy of first choice.

  11. Laryngopharyngeal pH measurement

    OpenAIRE

    Spurrier, E; Clancy, M; Deakin, C

    2004-01-01

    Methods: Cohorts of unconscious adult ED and elective surgical patients were recruited. The posterior pharyngeal wall pH was measured immediately before and after intubation. Pharyngeal pH was used to indicate risk of aspiration, and pH change to assess the efficacy of cricoid pressure.

  12. Almost contact metric 3-submersions

    Directory of Open Access Journals (Sweden)

    Bill Watson

    1984-01-01

    Full Text Available An almost contact metric 3-submersion is a Riemannian submersion, π from an almost contact metric manifold (M4m+3,(φi,ξi,ηii=13,g onto an almost quaternionic manifold (N4n,(Jii=13,h which commutes with the structure tensors of type (1,1;i.e., π*φi=Jiπ*, for i=1,2,3. For various restrictions on ∇φi, (e.g., M is 3-Sasakian, we show corresponding limitations on the second fundamental form of the fibres and on the complete integrability of the horizontal distribution. Concommitantly, relations are derived between the Betti numbers of a compact total space and the base space. For instance, if M is 3-quasi-Saskian (dΦ=0, then b1(N≤b1(M. The respective φi-holomorphic sectional and bisectional curvature tensors are studied and several unexpected results are obtained. As an example, if X and Y are orthogonal horizontal vector fields on the 3-contact (a relatively weak structure total space of such a submersion, then the respective holomorphic bisectional curvatures satisfy: Bφi(X,Y=B′J′i(X*,Y*−2. Applications to the real differential geometry of Yarg-Milis field equations are indicated based on the fact that a principal SU(2-bundle over a compactified realized space-time can be given the structure of an almost contact metric 3-submersion.

  13. Barrier/Cu contact resistivity

    Energy Technology Data Exchange (ETDEWEB)

    Reid, J.S.; Nicolet, M.A. [California Inst. of Tech., Pasadena, CA (United States); Angyal, M.S.; Lilienfeld, D.; Shacham-Diamand, Y. [Cornell Univ., Ithaca, NY (United States); Smith, P.M. [Sandia National Labs., Albuquerque, NM (United States)

    1995-10-17

    The specific contact resistivity of Cu with ({alpha} + {beta})-Ta, TiN, {alpha}-W, and amorphous-Ta{sub 36}Si{sub 14}N{sub 50} barrier films is measured using a novel four-point-probe approach. Geometrically, the test structures consist of colinear sets of W-plugs to act as current and voltage probes that contact the bottom of a planar Cu/barrier/Cu stack. Underlying Al interconnects link the plugs to the current source and voltmeter. The center-to-center distance of the probes ranges from 3 to 200 {micro}m. Using a relation developed by Vu et al., a contact resistivity of roughly 7 {times} 10{sup {minus}9} {Omega} cm{sup 2} is obtained for all tested barrier/Cu combinations. By reflective-mode small-angle X-ray scattering, the similarity in contact resistivity among the barrier films may be related to interfacial impurities absorbed from the deposition process.

  14. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... about the members of the eye-care team . Consumer warning about the improper use of colored contact ... About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of ...

  15. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Patient Stories Español Eye Health / News Halloween Hazard: The Hidden Dangers of Buying Decorative Contact Lenses Without ... been properly fitted by an eye care professional, the lenses stuck to my eye like a suction ...

  16. Tomato contact dermatitis

    DEFF Research Database (Denmark)

    Paulsen, Evy; Christensen, Lars P; Andersen, Klaus Ejner

    2012-01-01

    The tomato plant (Solanum lycopersicum) is an important crop worldwide. Whereas immediate-type reactions to tomato fruits are well known, contact dermatitis caused by tomatoes or tomato plants is rarely reported. The aims of this study were to present new data on contact sensitization to tomato...... plants and review the literature on contact dermatitis caused by both plants and fruits. An ether extract of tomato plants made as the original oleoresin plant extracts, was used in aimed patch testing, and between 2005 and 2011. 8 of 93 patients (9%) tested positive to the oleoresin extracts....... This prevalence is in accordance with the older literature that reports tomato plants as occasional sensitizers. The same applies to tomato fruits, which, in addition, may cause protein contact dermatitis. The allergens of the plant are unknown, but both heat-stable and heat-labile constituents seem...

  17. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her with a corneal abrasion. ... Studies Look at Effects of Marijuana on Vision FEB ...

  18. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... lentes de contacto de color Sep. 26, 2013 It started as an impulsive buy from a souvenir ... Can Ruin Vision Eye Makeup Safety In fact, it is illegal to sell colored contact lenses without ...

  19. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms ...

  20. Contact Lens Risks

    Science.gov (United States)

    ... Tap and distilled water have been associated with Acanthamoeba keratitis, a corneal infection that is resistant to ... to: Advice for Patients With Soft Contact Lenses: Acanthamoeba Keratitis Infections Related to Complete® MoisturePlus Multi Purpose ...

  1. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses you are ... from dry eye now have a completely new, drug-free alternative to lubricating eye drops and topical ...

  2. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... shop, but 10 hours after she first put in a pair of colored contact lenses, Laura Butler of Parkersburg, W.Va., had "extreme pain in both eyes," she said. "Because I had not ...

  3. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ... ask for a prescription. There is no such thing as a "one size fits all" contact lens. ...

  4. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... also available in Spanish . Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical ...

  5. Fragrance allergic contact dermatitis.

    Science.gov (United States)

    Cheng, Judy; Zug, Kathryn A

    2014-01-01

    Fragrances are a common cause of allergic contact dermatitis in Europe and in North America. They can affect individuals at any age and elicit a spectrum of reactions from contact urticaria to systemic contact dermatitis. Growing recognition of the widespread use of fragrances in modern society has fueled attempts to prevent sensitization through improved allergen identification, labeling, and consumer education. This review provides an overview and update on fragrance allergy. Part 1 discusses the epidemiology and evaluation of suspected fragrance allergy. Part 2 reviews screening methods, emerging fragrance allergens, and management of patients with fragrance contact allergy. This review concludes by examining recent legislation on fragrances and suggesting potential additions to screening series to help prevent and detect fragrance allergy.

  6. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology ...

  7. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... 2016 More Eye Health News Studies Look at Effects of Marijuana on Vision FEB 28, 2017 By ...

  8. Colored Contact Lens Dangers

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    Full Text Available ... Contact Lens-Related Eye Infections Mar 01, 2017 New Technology Helps the Legally Blind Be More Independent ... Worse? May 16, 2016 More Eye Health News New Dry Eye Treatment is a Tear-Jerker JUL ...

  9. Colored Contact Lens Dangers

    Science.gov (United States)

    ... Prevention News Ask an Ophthalmologist Patient Stories Español Eye Health / News Halloween Hazard: The Hidden Dangers of Buying Decorative Contact Lenses Without a Prescription Sep. 26, 2013 It started ...

  10. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Hidden Dangers of Buying Decorative Contact Lenses Without a Prescription Leer en Español: Peligros asociados con los ... contacto de color Sep. 26, 2013 It started as an impulsive buy from a souvenir shop, but ...

  11. Colored Contact Lens Dangers

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    Full Text Available ... Healthy Contact Lens Use May 31, 2016 Is El Niño Making Your Allergies Worse? May 16, 2016 ... Number: * Email: * Enter code: * Message: Thank you Your feedback has been sent.

  12. Colored Contact Lens Dangers

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    Full Text Available ... Patient Stories Español Eye Health / News Halloween Hazard: The Hidden Dangers of Buying Decorative Contact Lenses Without ... been properly fitted by an eye care professional, the lenses stuck to my eye like a suction ...

  13. Pediatric contact dermatitis

    OpenAIRE

    Sharma Vinod; Asati Dinesh

    2010-01-01

    Allergic contact dermatitis (ACD) in children, until recently, was considered rare. ACD was considered as a disorder of the adult population and children were thought to be spared due to a lack of exposure to potential allergens and an immature immune system. Prevalence of ACD to even the most common allergens in children, like poison ivy and parthenium, is relatively rare as compared to adults. However, there is now growing evidence of contact sensitization of the pediatric population, and i...

  14. Contact air abrasion.

    Science.gov (United States)

    Porth, R

    1999-05-01

    The advantages of contact air abrasion techniques are readily apparent. The first, of course, is the greatly increased ease of use. Working with contact also tends to speed the learning curve by giving the process a more natural dental feel. In addition, as one becomes familiar with working with a dust stream, the potential for misdirecting the air flow is decreased. The future use of air abrasion for deep decay removal will make this the treatment of choice for the next millennium.

  15. Contact angle hysteresis on fluoropolymer surfaces.

    Science.gov (United States)

    Tavana, H; Jehnichen, D; Grundke, K; Hair, M L; Neumann, A W

    2007-10-31

    Contact angle hysteresis of liquids with different molecular and geometrical properties on high quality films of four fluoropolymers was studied. A number of different causes are identified for hysteresis. With n-alkanes as probe liquids, contact angle hysteresis is found to be strongly related to the configuration of polymer chains. The largest hysteresis is obtained with amorphous polymers whereas the smallest hysteresis occurs for polymers with ordered molecular chains. This is explained in terms of sorption of liquid by the solid and penetration of liquid into the polymer film. Correlation of contact angle hysteresis with the size of n-alkane molecules supports this conclusion. On the films of two amorphous fluoropolymers with different molecular configurations, contact angle hysteresis of one and the same liquid with "bulky" molecules is shown to be quite different. On the surfaces of Teflon AF 1600, with stiff molecular chains, the receding angles of the probe liquids are independent of contact time between solid and liquid and similar hysteresis is obtained for all the liquids. Retention of liquid molecules on the solid surface is proposed as the most likely cause of hysteresis in these systems. On the other hand, with EGC-1700 films that consist of flexible chains, the receding angles are strongly time-dependent and the hysteresis is large. Contact angle hysteresis increases even further when liquids with strong dipolar intermolecular forces are used. In this case, major reorganization of EGC-1700 chains due to contact with the test liquids is suggested as the cause. The effect of rate of motion of the three-phase line on the advancing and receding contact angles, and therefore contact angle hysteresis, is investigated. For low viscous liquids, contact angles are independent of the drop front velocity up to approximately 10 mm/min. This agrees with the results of an earlier study that showed that the rate-dependence of the contact angles is an issue only

  16. Multibody dynamic simulation of knee contact mechanics.

    Science.gov (United States)

    Bei, Yanhong; Fregly, Benjamin J

    2004-11-01

    Multibody dynamic musculoskeletal models capable of predicting muscle forces and joint contact pressures simultaneously would be valuable for studying clinical issues related to knee joint degeneration and restoration. Current three-dimensional multibody knee models are either quasi-static with deformable contact or dynamic with rigid contact. This study proposes a computationally efficient methodology for combining multibody dynamic simulation methods with a deformable contact knee model. The methodology requires preparation of the articular surface geometry, development of efficient methods to calculate distances between contact surfaces, implementation of an efficient contact solver that accounts for the unique characteristics of human joints, and specification of an application programming interface for integration with any multibody dynamic simulation environment. The current implementation accommodates natural or artificial tibiofemoral joint models, small or large strain contact models, and linear or nonlinear material models. Applications are presented for static analysis (via dynamic simulation) of a natural knee model created from MRI and CT data and dynamic simulation of an artificial knee model produced from manufacturer's CAD data. Small and large strain natural knee static analyses required 1 min of CPU time and predicted similar contact conditions except for peak pressure, which was higher for the large strain model. Linear and nonlinear artificial knee dynamic simulations required 10 min of CPU time and predicted similar contact force and torque but different contact pressures, which were lower for the nonlinear model due to increased contact area. This methodology provides an important step toward the realization of dynamic musculoskeletal models that can predict in vivo knee joint motion and loading simultaneously.

  17. Double pendulum contact problem

    Directory of Open Access Journals (Sweden)

    Špička J.

    2014-06-01

    Full Text Available The work concerns contact problems focused on biomechanical systems modelled by a multibody approach. The example is modelling of impact between a body and an infrastructure. The paper firstly presents algorithm for minimum distance calculation. An analytical approach using a tangential plain perpendicular to an initial one is applied. Contact force generated during impact is compared by three different continuous force models, namely the Hertz’s model, the spring-dashpot model and the non-linear damping model. In order to identify contact parameters of these particular models, the method of numerical optimization is used. Purpose of this method is to find the most corresponding results of numerical simulation to the original experiment. Numerical optimization principle is put upon a bouncing ball example for the purpose of evaluation of desirable contact force parameters. The contact modelling is applied to a double pendulum problem. The equation of motion of the double pendulum system is derived using Lagrange equation of the second kind with multipliers, respecting the contact phenomena. Applications in biomechanical research are hinted at arm gravity motion and a double pendulum impact example.

  18. Patients with multiple contact allergies

    DEFF Research Database (Denmark)

    Carlsen, Berit Christina; Andersen, Klaus Ejner; Menné, Torkil;

    2008-01-01

    Patients with multiple contact allergies, also referred to as polysensitized, are more frequent than predicted from prevalence of single sensitivities. The understanding of why some people develop multiple contact allergies, and characterization of patients with multiple contact allergies...... of developing multiple contact allergies. Evidence of allergen clusters among polysensitized individuals is also reviewed. The literature supports the idea that patients with multiple contact allergies constitute a special entity within the field of contact allergy. There is no generally accepted definition...... of patients with multiple contact allergies. We suggest that contact allergy to 3 or more allergens are defined as multiple contact allergies....

  19. Surrogate Modeling of Deformable Joint Contact using Artificial Neural Networks

    Science.gov (United States)

    Eskinazi, Ilan; Fregly, Benjamin J.

    2016-01-01

    Deformable joint contact models can be used to estimate loading conditions for cartilage-cartilage, implant-implant, human-orthotic, and foot-ground interactions. However, contact evaluations are often so expensive computationally that they can be prohibitive for simulations or optimizations requiring thousands or even millions of contact evaluations. To overcome this limitation, we developed a novel surrogate contact modeling method based on artificial neural networks (ANNs). The method uses special sampling techniques to gather input-output data points from an original (slow) contact model in multiple domains of input space, where each domain represents a different physical situation likely to be encountered. For each contact force and torque output by the original contact model, a multi-layer feed-forward ANN is defined, trained, and incorporated into a surrogate contact model. As an evaluation problem, we created an ANN-based surrogate contact model of an artificial tibiofemoral joint using over 75,000 evaluations of a fine-grid elastic foundation (EF) contact model. The surrogate contact model computed contact forces and torques about 1000 times faster than a less accurate coarse grid EF contact model. Furthermore, the surrogate contact model was seven times more accurate than the coarse grid EF contact model within the input domain of a walking motion. For larger input domains, the surrogate contact model showed the expected trend of increasing error with increasing domain size. In addition, the surrogate contact model was able to identify out-of-contact situations with high accuracy. Computational contact models created using our proposed ANN approach may remove an important computational bottleneck from musculoskeletal simulations or optimizations incorporating deformable joint contact models. PMID:26220591

  20. What PhD students really want

    CERN Document Server

    Mao, Minnie

    2010-01-01

    The road to becoming an astronomer is exciting, but often fraught with danger and conflicting messages. A PhD student is inundated with catch-phrases such as "publish or perish" and "it's not about the quantity, but the quality of work". How do we know which advice to follow? How can we publish copious amounts of quality work in only three years so as to maximize our success in the future? How do we even know what "good quality" really is? With only a short time to prepare ourselves for the big wide world of Astronomy, what is the best way for a PhD student to maximize their research and ultimately maximize their success as a real astronomer? The PhD students of today are the astronomers of tomorrow, but their journey depends on a positive work environment in which they can thrive and improve. Here I present the results of a survey of current PhD students on how they believe they can maximize their success in science. I find that PhD students in Australia expect to write more papers during their PhD than is e...

  1. 断路器触头温度场实时监测系统设计%Design of temperature real-time monitoring system for circuit breaker contact

    Institute of Scientific and Technical Information of China (English)

    伍珊珊; 罗日成; 张正; 黄辉虎

    2012-01-01

    SF6断路器触头温度场的实时监测是电气设备绝缘检测领域长期存在的技术难题,设计一种新型的单端口SAW谐振器构成的无源无线温度传感装置,构建断路器温度监测系统.分析并设计低功耗发射器电路和接收电路,对其性能参数进行计算;研究SAW传感器发射和接收天线的辐射电阻、损耗电阻和电感等参数的取值问题,并根据这些参数设计匹配网络,从而提高通讯距离及通讯的可靠性.该装置经测试,可以满足现场对SF6断路器触头温度的实时监测要求.%Temperature real-time monitoring for circuit breaker contact is a technical problem of e-lectric equipment insulation monitoring. In order to solve the problem, a SAW temperature sensor based passive wireless monitor system was designed in this paper. A temperature measuring system was built to test the performance of the sensor. The low power transmission and receiving circuits were designed. The transmission and radiation resistance characteristics of the receiving antenna, the loss resistance and the inductance were analyzed with network matching to improve the reliability and stability of the wireless communication. This system has the advantage of easily control, high accuracy, high reliability, and it can achieve the function of SF6 circuit breaker contact temperature measurement.

  2. 基于稀土铕离子配合物的时间分辨荧光pH 探针的合成及应用%The Synthesis and Application of Time-Resolved Fluorescence pH Probe Based on Rare Earth Europium Ion Complex

    Institute of Scientific and Technical Information of China (English)

    黄大伟; 邴永鑫; 洪伟; 崔恺; 虢清伟

    2016-01-01

    A rare earth ternary europium ion complex with fluorescent lifetime of 0.544 0 ms was synthesized by using 4,7-diphenyl-1,10-phenanthroline and 2-thenoyltrifluoroacetone as synergic agents andβ-diketone ligands. The complex was used as fluorescent probe for pH determination of environmental water samples by time-resolved fluorescence analysis.The fluorescent probe showed the maximum and stable time-resolved fluorescence intensity when the pH ranged from 7.00 to 8.95,while the time-resolved fluorescence intensity changed obviously in acidic (pH 8.95 )conditions.The time-resolved fluorescence quenching of the fluorescent probe showed linear response toward pH in the range of 2.50-7.00 or 9.91 -14.00.The prepared fluorescent probe was insensitive to dissolved oxygen and ionic strength.The prepared fluorescent probe was used to determine pH of real water samples,giving results in consistent with those obtained by glass electrode and RSDs (n=8)in the range of 4.3%-8.1%.%以4,7-二苯基-1,10-菲啉(母体)和2-噻吩甲酰三氟丙酮为协同剂和β-二酮配体,合成了一种稀土三元铕离子配合物,其荧光寿命为0.5440 ms,并以其为荧光探针对水环境的 pH 进行时间分辨荧光测定。荧光探针的时间分辨荧光强度在 pH 7.00~8.95时达到最大值并保持较好的稳定性;在 pH 小于7.00和 pH 大于8.95时,荧光探针的时间分辨荧光强度随着 pH 变化而变化;在 pH 2.50~7.00和 pH 9.91~14.00时,荧光探针的时间分辨荧光猝灭率与 pH 呈线性关系。溶解氧浓度和离子强度变化对 pH 测定结果无影响。采用荧光探针测定实际水样的 pH,结果与玻璃电极的测定结果相符,测定值的相对标准偏差(n=8)在4.3%~8.1%之间。

  3. MANUFACTURE OF FIBER OPTIC SENSORS TO MEASURE THE PH WATER

    Directory of Open Access Journals (Sweden)

    Bushra R. Mahdi

    2016-07-01

    Full Text Available A fiber-optic pH sensor based on evanescent wave penetration is presented. Evanescent wave penetration is generated by removing the clad and contact the core with the solution. Testing samples were perpetrated by add a strong acid (HCL or a strong base (NaOH at distilled water to produce different value of pH (from 4 to 13. To determine the absorption or transmission of the evanescent waves, that generate after where obtained on appropriate calibration curve to determine a wide range of pH, by using pH indicators. Where using methyl red, by add fixed amounts of this dyes to the water samples were obtained on samples with colors vary with pH values. Calculate the transmission and absorption with draw a relationship between the transmissions or absorption with the pH values, to obtain on suitable curves, considered as calibration curves. Calibration curve for methyl red is best, where extends (from 4 to 12 for pH value. Can calculate the pH value for any water sample to tested, by the add the same ratios of the organic dyes it used.

  4. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2003-12-01

    Full Text Available Report of PhD Dissertations. Guido Antonioli Conservator pacis et iustitie. La signoria di Taddeo Pepoli a Bologna (1337-1347, Tesi di dottorato di ricerca in Filologia romanza e cultura medievale (XIII ciclo, Università degli Studi di Bologna, 2001   Elisabetta Filippini «In vassallatico episcopi permanere debent». Rapporti vassallatici e concessioni beneficiali dei vescovi di Cremona fra X e XIII secolo, Tesi di dottorato di Ricerca in Storia Medievale (XV ciclo, Università Cattolica del Sacro Cuore di Milano, 2003   Marco Meschini, Innocenzo III e il "negotium pacis et fidei" in Linguadoca tra il 1198 e il 1215, Tesi di dottorato di ricerca in Storia medievale, Università Cattolica del Sacro Cuore, 2003   Fabrizio Ricciardelli The Politics of Exclusion in Florence (1215-1434, thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in History, University of Warwick, Department of History, April 2003 Renata Salvarani Baptizare pueros et decimas dare. Cura delle anime, strutturazione ecclesiastica e organizzazione delle campagne in area gardesana fra VIII e XIII secolo (diocesi di Brescia, Verona, Mantova e Trento, Tesi di dottorato in Storia medievale (XV ciclo, Università Cattolica del Sacro Cuore di Milano, 2002-2003   Vito Sibilio Le parole della prima crociata, Tesi di dottorato di ricerca in Storia dei centri delle vie e della cultura dei pellegrinaggi nel medioevo euromediterraneo, Università degli studi di Lecce, 2003

  5. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2000-06-01

    Full Text Available Report of PhD Dissertations.   Miguel Calleja Puerta El conde Suero Vermúdez, su parentela y su entorno social. La aristocracia leonesa en los siglos XI y XII, Tesis de doctorado en Historia, Universidad de Oviedo (España, 2000   Adele Cilento Potere e monachesimo nella Calabria bizantina: relazioni e interferenze (secc. IX-XI, Tesi di dottorato di ricerca in Storia medievale (X ciclo, Università degli Studi di Torino, 2000   Amedeo De Vincentiis Firenze e i signori. Sperimentazioni istituzionali e modelli di regime nelle signorie fiorentine degli Angioini (fine XIII - metà XIV secolo, Tesi di dottorato di ricerca in Storia medioevale (XI ciclo, Università degli Studi di Milano, 1999   Marco Folin Il sistema politico di un antico Stato italiano: i ducati estensi nella prima Età moderna (1452-1598, Tesi di dottorato di ricerca in Storia, Scuola Normale superiore di Pisa, 2000   Barbara Frale Guardiani del Santuario. Le radici orientali del processo contro l’ordine del Tempio (1128 - 1314, Tesi di dottorato di ricerca in Storia sociale d’Europa (XI ciclo, Università "Ca’ Foscari" di Venezia, 2000

  6. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2003-06-01

    Full Text Available Reporto of PhD Dissertations.   Mario Dalle Carbonare Società, potere e clientele nell’Irlanda altomedievale (secoli V-IX, Tesi di dottorato di ricerca in Storia sociale europea, Università "Ca' Foscari" di Venezia, 2003 Vieri Mazzoni La legislazione antighibellina e la politica oligarchica della Parte Guelfa di Firenze nel secondo Trecento (1347-1378, Tesi di dottorato di ricerca in Storia Medievale (ciclo XII, Università degli Studi di Firenze   Alma Poloni Pisa dalle origini del movimento popolare alla discesa di Ludovico il Bavaro. I gruppi dirigenti cittadini tra continuità e trasformazione, Tesi di dottorato di ricerca in Storia dell'Europa nel medioevo, Università degli studi di Pisa, 2003   Andrea Puglia Potere marchionale, amministrazione del territorio, società locali dalla morte di Ugo di Tuscia a Guelfo VI di Baviera (1001-1160, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Milano, 2003

  7. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2010-06-01

    Full Text Available Report of PhD dissertations. Andrea Brugnoli Una storia locale: l’organizzazione del territorio veronese nel medioevo: trasformazioni della realtà e schemi notarili (IX-metà XII secolo, Tesi di dottorato di ricerca in Scienze Storiche e Antropologiche (XXII ciclo, Università degli Studi di Verona, 2010   Luca Filangieri Famiglie e gruppi dirigenti a Genova (secoli XII-metà XIII, Tesi di dottorato di ricerca in Storia medievale (XXII ciclo, Università degli Studi di Firenze, 2010   Jakub Kujawi ski Wernakularna kolekcja historiograficzna z rękopisu francuskiego nr 688 z Biblioteki Narodowej w Paryżu. Studium źródłoznawcze (La raccolta dei volgarizzamenti delle opere storiografiche nel manoscritto francese 688 della Biblioteca Nazionale di Parigi, Tesi di dottorato, Università “Adam Mickiewicz”, Facoltà di Storia, Pozna, a.a. 2009/2010   Marta Longhi I signori “de Radicata”. Strategie di affermazione familiare e patrimoniale nel Piemonte dei secoli XII-XIV, Tesi di dottorato di ricerca in Istituzioni, Società, Religioni dal Tardo Antico alla fine del Medioevo (XX ciclo, Università di Torino, 2008

  8. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2004-06-01

    Full Text Available Report of PhD Dissertations. Francesco Barone Istituzioni, società ed economia a Catania nel tardo medioevo (XIV-XV secolo, Tesi di dottorato in Storia medievale (XVI ciclo, Università degli Studi di Firenze, 2004   Laura Berti Ceroni Il territorio e le strutture di Cesarea e Classe tra tarda antichità e alto medioevo in rapporto con Ravenna, Tesi di dottorato di ricerca in Storia e Informatica, Università degli studi di Bologna, 2002-2003.   Marco Bicchierai Poppi dalla signoria dei conti Guidi al vicariato del Casentino (1360-1480, Tesi di dottorato in Storia medievale (XIV ciclo, Università degli Studi di Firenze, 2004   Emanuela Garimberti Spatiosa ad habitandum loca. Luoghi e identità nella Historia Langobardorum di Paolo Diacono, Tesi di dottorato in Storia medievale (XV ciclo, Università degli Studi di Bologna, 2004   Lorenzo Tanzini Sistemi normativi e pratiche istituzionali a Firenze dalla fine del XIII all’inizio del XV secolo, Tesi di dottorato di ricerca in Storia medievale (XVI ciclo, Università degli Studi di Firenze, 2004   Stefania Tarquini Pellegrinaggio e asseto urbano di Roma, Tesi di dottorato di ricerca in Storia dei centri, delle vie e della cultura dei pellegrinaggi nel Medioevo euro mediterraneo (XV ciclo, Università degli studi di Lecce, 2003

  9. ON?THE?ERROR?ESTIMATE?OF?LINEAR?FINITE?ELEMENT?APPROXIMATION?TO?THE?ELASTIC?CONTACT?PROBLEM? WITH?CURVED?CONTACT?BOUNDARY

    Institute of Scientific and Technical Information of China (English)

    Lie-heng Wang

    2000-01-01

    In this paper, the linear finite element approximation to the elastic contact problem with curved contact boundary is considered. The error bound O(h1-2) is obtained with requirements of two times continuously differentiable for contact boundary and the usual regular triangulation, while I.Hlavacek et. al. obtained the error bound O(h ) with requirements of three times continuously differentiable for contact boundary and extra regularities of triangulation (c.f. [2]).

  10. A Perturbation Result for Dynamical Contact Problems

    Institute of Scientific and Technical Information of China (English)

    Corinna Klapproth; Peter Deuflhard; Anton Schiela

    2009-01-01

    This paper is intended to be a first step towards the continuous dependence of dynamical contact problems on the initial data as well as the uniqueness of a solution. Moreover, it provides the basis for a proof of the convergence of popular time integration schemes as the Newmark method. We study a frictionless dynamical contact problem between both linearly elastic and viscoelastic bodies which is formulated via the Signorini contact conditions. For viscoelastic materials fulfilling the Kelvin-Voigt constitutive law, we find a characterization of the class of problems which satisfy a perturbation result in a non-trivial mix of norms in function space. This characterization is given in the form of a stability condition on the contact stresses at the contact boundaries. Furthermore, we present perturbation results for two well-established approximations of the classical Signorini condition: The Signorini condition formulated in velocities and the model of normal compliance, both satisfying even a sharper version of our stability condition.

  11. Experimental study on biopsy sampling using new flexible cryoprobes: influence of activation time, probe size, tissue consistency, and contact pressure of the probe on the size of the biopsy specimen.

    Science.gov (United States)

    Franke, Karl-Josef; Szyrach, Mara; Nilius, Georg; Hetzel, Jürgen; Hetzel, Martin; Ruehle, Karl-Heinz; Enderle, Markus D

    2009-08-01

    Cryoextraction is a procedure for recanalization of obstructed airways caused by exophytic growing tumors. Biopsy samples obtained with this method can be used for histological diagnosis. The objective of this study was to evaluate the parameters influencing the size of cryobiopsies in an in vitro animal model. New flexible cryoprobes with different diameters were used to extract biopsies from lung tissue. These biopsies were compared with forceps biopsy (gold standard) in terms of the biopsy size. Tissue dependency of the biopsy size was analyzed by comparing biopsies taken from the lung, the liver, and gastric mucosa. The effect of contact pressure exerted by the tip of the cryoprobe on the tissue was analyzed on liver tissue separately. Biopsy size was estimated by measuring the weight and the diameter. Weight and diameter of cryobiopsies correlated positively with longer activation times and larger diameters of the cryoprobe. The weight of the biopsies was tissue dependent: lung biopsy diameter. The biopsy size increased when the probe was pressed on the tissue during cooling. Cryobiopsies can be taken from different tissue types with flexible cryoprobes. The size of the samples depends on tissue type, probe diameter, application time, and pressure exerted by the probe on the tissue. Even the cryoprobe with the smallest diameter can provide larger biopsies than a forceps biopsy in lung. It can be expected that the same parameters influence the sample size of biopsies in vivo.

  12. Elastohydrodynamics of contact in adherent sheets

    CERN Document Server

    Carlson, Andreas; Mahadevan, L

    2015-01-01

    Adhesive contact between a thin elastic sheet and a substrate in a liquid environment arises in a range of biological, physical and technological applications. By considering the dynamics of this process that naturally couples fluid flow, long wavelength elastic deformations and microscopic adhesion, and solving the resulting partial differential equation numerically, we uncover the short-time dynamics of the onset of adhesion and the long-time dynamics of a steady propagating adhesion front. Simple scaling laws corroborate our results for characteristic waiting-time for adhesive contact, as well as the speed of the adhesion front. A similarity analysis of the governing partial differential equation further allows us to determine the shape of a fluid filled bump ahead of the adhesion zone. Finally, our analysis yields the boundary conditions for the apparent elastohydrodynamic contact line, generalizing the well known conditions for static elastic contact while highlighting how microscale physics regularizes ...

  13. Contact process with temporal disorder

    Science.gov (United States)

    Barghathi, Hatem; Vojta, Thomas; Hoyos, José A.

    2016-08-01

    We investigate the influence of time-varying environmental noise, i.e., temporal disorder, on the nonequilibrium phase transition of the contact process. Combining a real-time renormalization group, scaling theory, and large scale Monte-Carlo simulations in one and two dimensions, we show that the temporal disorder gives rise to an exotic critical point. At criticality, the effective noise amplitude diverges with increasing time scale, and the probability distribution of the density becomes infinitely broad, even on a logarithmic scale. Moreover, the average density and survival probability decay only logarithmically with time. This infinite-noise critical behavior can be understood as the temporal counterpart of infinite-randomness critical behavior in spatially disordered systems, but with exchanged roles of space and time. We also analyze the generality of our results, and we discuss potential experiments.

  14. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2005-06-01

    Full Text Available Report of PhD Dissertations. Federica Cengarle Le investiture feudali di Filippo Maria Visconti (1412-1447, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Milano, 2005 Silvia Coazzin Liberi domini totius castri. L'aristocrazia rurale "minore" nel Senese e nella Toscana meridionale. Forme di egemonia, assetto sociale e patrimoniale di lignaggi, famiglie e gruppi consortili di castello (secc. XI-XIV, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 Maria Elena Cortese Signori e castelli. Famiglie aristocratiche, dominati signorili e trasformazioni insediative nel comitatus fiorentino (fine X-metà XII secolo, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 Patrizia Meli Gabriele Malaspina marchese di Fosdinovo: il condottiero ed il politico, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 Federica Pessotto La Morea franca. Economia e istituzioni tra Oriente e Occidente nei secoli XIII e XIV, Tesi di dottorato di ricerca in Istituzioni, Società e Religioni dal Tardoantico alla fine del Medioevo, Università degli studi di Torino, 2003 Lorenzo Pubblici Dal Caucaso al Mar d’Azov. L’impatto dell’invasione mongola nella Caucasia fra nomadismo e civiltà sedentaria (1204-1395, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 [01/05] Riccardo Rao "Comunia". Risorse collettive e patrimoniali dei maggiori comuni subalpini (secoli XII - inizio XIV, Tesi di dottorato di ricerca in Storia medioevale, Università degli Studi di Milano, 2005 Alessandro Soddu Feudalesimo e potere signorile in Sardegna nei secoli XI-XIV.  La signoria territoriale dei Malaspina, Tesi di dottorato di ricerca in Storia, Università "Pompeu Fabra" di Barcellona, 2004

  15. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2002-06-01

    Full Text Available Report of PhD dissertation. Laura Baietto Una politica per le città. Rapporti fra papato, vescovi e comuni nell'Italia centro-settentrionale da Innocenzo III a Gregorio IX, Tesi di dottorato di ricerca in Storia Medievale, Università degli Studi di Torino, 2002   Giuseppe Banfo Compresenze e sovrapposizioni di poteri territoriali di qualità diversa tra X e XIII: il caso del basso Monferrato, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Torino, 2002   Francesca Dell'Acqua La vetrata tra l'età tardo imperiale e l'altomedioevo: le fonti, l'archeologia, Tesi di Perfezionamento in Storia dell'Arte Medievale, Scuola Normale Superiore di Pisa, 2001   Primo Giovanni Embriaco I vescovi di Albenga e gli sviluppi signorili nella Liguria occidentale (secoli XI-XIII, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Torino, 2001   Antonella Ghignoli Documenti e proprietà altomedievali. Fondamenti e problemi dell'esegesi storica delle fonti documentarie nello specchio della tradizione delle carte pisane dei secoli VIII-XI, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Firenze, 2002   Vito Loré Espansione monastica e mutamenti politici. La Trinità di Cava nei suoi rapporti con i sovrani longobardi e normanni e con l'aristocrazia territoriale. Secoli XI-XII, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Firenze, 2002   Rosaria Stracuzzi Messina nel '400, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Palermo, 2001   Stefania Tamburini Le "portate" ecclesiastiche nel piviere di San Giovanni in Firenze nel 1427. Spunti per una riflessione sul patrimonio ecclesiastico della diocesi fiorentina,Tesi di dottorato di ricerca in Storia e informatica, Università degli Studi di Bologna, 2001

  16. Achromobacter xylosoxidans keratitis after contact lens usage.

    Science.gov (United States)

    Park, Jung Hyun; Song, Nang Hee; Koh, Jae Woong

    2012-02-01

    To report on Achromobacter xylosoxidans keratitis in two healthy patients who had worn contact lenses foran extended period of time. A 36-year-old female and a 21-year-old female visited our hospital with ocular pain and blurred vision. Both patients had a history of wearing soft contact lenses for over fve years with occasional overnight wear. At the initial presentation, a slit lamp examination revealed corneal stromal infiltrations and epithelial defects with peripheral neovascularization in both patients. Microbiological examinations were performed from samples of corneal scrapings, contact lenses, contact lens cases, and solution. The culture resulting from the samples taken from the contact lenses, contact lens cases, and solution were all positive for Achromobacter xylosoxidans. Confrming that the direct cause of the keratitis was the contact lenses, the frst patient was prescribed ceftazidime and amikacin drops sensitive to Achromobacter xylosoxidans. The second patient was treated with 0.3% gatifoxacin and fortifed tobramycin drops. After treatment, the corneal epithelial defects were completely healed, and subepithelial corneal opacity was observed. Two cases of Achromobacter xylosoxidans keratitis were reported in healthy young females who wore soft contact lenses. Achromobacter xylosoxidans should be considered a rare but potentially harmful pathogen for lens-induced keratitis in healthy hosts.

  17. Rough Surface Contact

    Directory of Open Access Journals (Sweden)

    T Nguyen

    2017-06-01

    Full Text Available This paper studies the contact of general rough curved surfaces having nearly identical geometries, assuming the contact at each differential area obeys the model proposed by Greenwood and Williamson. In order to account for the most general gross geometry, principles of differential geometry of surface are applied. This method while requires more rigorous mathematical manipulations, the fact that it preserves the original surface geometries thus makes the modeling procedure much more intuitive. For subsequent use, differential geometry of axis-symmetric surface is considered instead of general surface (although this “general case” can be done as well in Chapter 3.1. The final formulas for contact area, load, and frictional torque are derived in Chapter 3.2.

  18. Acrylate Systemic Contact Dermatitis.

    Science.gov (United States)

    Sauder, Maxwell B; Pratt, Melanie D

    2015-01-01

    Acrylates, the 2012 American Contact Dermatitis Society allergen of the year, are found in a range of products including the absorbent materials within feminine hygiene pads. When fully polymerized, acrylates are nonimmunogenic; however, if not completely cured, the monomers can be potent allergens.A 28-year-old woman is presented, who had her teeth varnished with Isodan (Septodont, Saint-Maur-des-Fossés, France) containing HEMA (2-hydroxyethyl methacrylate) with no initial reaction. Approximately 1 month later, the patient developed a genital dermatitis secondary to her feminine hygiene pads. The initial reaction resolved, but 5 months later, the patient developed a systemic contact dermatitis after receiving a second varnishing.The patient was dramatically patch test positive to many acrylates. This case demonstrates a reaction to likely unpolymerized acrylates within a feminine hygiene pad, as well as broad cross-reactivity or cosensitivity to acrylates, and possibly a systemic contact dermatitis with systemic re-exposure to unpolymerized acrylates.

  19. Shoe allergic contact dermatitis.

    Science.gov (United States)

    Matthys, Erin; Zahir, Amir; Ehrlich, Alison

    2014-01-01

    Foot dermatitis is a widespread condition, affecting men and women of all ages. Because of the location, this condition may present as a debilitating problem to those who have it. Allergic contact dermatitis involving the feet is frequently due to shoes or socks. The allergens that cause shoe dermatitis can be found in any constituent of footwear, including rubber, adhesives, leather, dyes, metals, and medicaments. The goal of treatment is to identify and minimize contact with the offending allergen(s). The lack of product information released from shoe manufacturers and the continually changing trends in footwear present a challenge in treating this condition. The aim of this study is to review the current literature on allergic contact shoe dermatitis; clinical presentation, allergens, patch testing, and management will be discussed. PubMed and MEDLINE databases were used for the search, with a focus on literature updates from the last 15 years.

  20. Effect of inoculum size, bacterial species, type of surfaces and contact time to the transfer of foodborne pathogens from inoculated to non-inoculated beef fillets via food processing surfaces.

    Science.gov (United States)

    Gkana, E; Chorianopoulos, N; Grounta, A; Koutsoumanis, K; Nychas, G-J E

    2017-04-01

    The objective of the present study was to determine the factors affecting the transfer of foodborne pathogens from inoculated beef fillets to non-inoculated ones, through food processing surfaces. Three different levels of inoculation of beef fillets surface were prepared: a high one of approximately 10(7) CFU/cm(2), a medium one of 10(5) CFU/cm(2) and a low one of 10(3) CFU/cm(2), using mixed-strains of Listeria monocytogenes, or Salmonella enterica Typhimurium, or Escherichia coli O157:H7. The inoculated fillets were then placed on 3 different types of surfaces (stainless steel-SS, polyethylene-PE and wood-WD), for 1 or 15 min. Subsequently, these fillets were removed from the cutting boards and six sequential non-inoculated fillets were placed on the same surfaces for the same period of time. All non-inoculated fillets were contaminated with a progressive reduction trend of each pathogen's population level from the inoculated fillets to the sixth non-inoculated ones that got in contact with the surfaces, and regardless the initial inoculum, a reduction of approximately 2 log CFU/g between inoculated and 1st non-inoculated fillet was observed. S. Typhimurium was transferred at lower mean population (2.39 log CFU/g) to contaminated fillets than E. coli O157:H7 (2.93 log CFU/g), followed by L. monocytogenes (3.12 log CFU/g; P CFU/g) enhanced the transfer of bacteria to subsequent fillets compared to other materials (2.66 log CFU/g for SS and PE; P < 0.05). Cross-contamination between meat and surfaces is a multifactorial process strongly depended on the species, initial contamination level, kind of surface, contact time and the number of subsequent fillet, according to analysis of variance. Thus, quantifying the cross-contamination risk associated with various steps of meat processing and food establishments or households can provide a scientific basis for risk management of such products.

  1. What My Ph.D. Taught Me

    Science.gov (United States)

    Levenstein, Jessica

    2013-01-01

    The author started in the Ph.D. program in comparative literature at Princeton in 1992, a year after she graduated from college. She fell in love with mythology and the classical traditions and find herself teaching literature. In the remainder of her time at Princeton, she precepted for four or five more classes, got the chance to join the…

  2. The Cambridge Bachelor of Medicine (MB)/Doctor of Philosophy (PhD): graduate outcomes of the first MB/PhD programme in the UK.

    Science.gov (United States)

    Cox, Timothy M; Brimicombe, James; Wood, Diana F; Peters, D Keith

    2012-12-01

    We reviewed outcomes of the Cambridge Bachelor of Medicine (MB)/Doctor of Philosophy (PhD) programme for the period 1989-2010. Of the 90 alumni contacted, 80 (89%; 24 women) completed an anonymous questionnaire. Thirty were academic staff and 35 were in general professional (core) or higher medical training. Of the latter, 11 were specialty registrars, six were academic clinical fellows and three held academic foundation year posts. Eight alumni were overseas, including five in North America. Most (95%) respondents considered that their academic career goals were facilitated by the programme. Sixty-eight of the 80 alumni had conducted further research, 63 (79%) were active in research, and 90% had explicit plans for further full-time research. Twelve graduates had further substantive research support (six clinician scientist awards and three senior fellowships) and two were Wellcome Trust postdoctoral MB/PhD fellows. Alumni included two full university professors, one reader, six senior lecturers, two assistant professors and nine university clinical lecturers. MB/PhD programmes offer an alternative training pathway for clinician-scientists in UK medical schools: the Cambridge programme promotes scientific discovery and sustained academic development within the context of contemporary medicine and clinical practice.

  3. Allergic contact dermatitis.

    Science.gov (United States)

    Gober, Michael D; Gaspari, Anthony A

    2008-01-01

    Allergic contact dermatitis is a classic example of a cell mediated hypersensitivity reaction in the skin. This occurs as a result of xenobiotic chemicals penetrating into the skin, chemically reacting with self proteins, eventually resulting in a hapten-specific immune response. It is precisely because of this localized immune response that allergic signs and symptoms occur (redness, edema, warmth and pruritus). It has been known for years that conventional T-cells (CD4+ or CD8+ T-cells that express a T-cell receptor alpha/Beta) are critical effectors for this reaction. There is emerging evidence that innate immune lymphocytes such as invariant Natural killer T-cells and even Natural killer cells may play important role. Other T-cell types such as Tregulatory cells and the IL-10 secreting Tregulatory cells type I are likely to be important in the control (resolution) of allergic contact dermatitis. Other cell types that may contribute include B-cells and hapten-specific IgM. Additionally, epidermal Langerhans cells have been ascribed an indispensable role as an antigen presenting cell to educate T-cells of the skin immune system. Studies of mice that lack this cell type suggest that Langerhans cells may be dispensible, and may even play a regulatory role in allergic contact dermatitis. The identity of the antigen presenting cells that complement Langerhans cells has yet to be identified. Lastly, Keratinocytes play a role in all phases of allergic contact dermatitis, from the early initiation phase with the elaboration of inflammatory cytokines, that plays a role in Langerhans cell migration, and T-cell trafficking, through the height of the inflammatory phase with direct interactions with epidermotrophic T-cells, through the resolution phase of allergic contact dermatitis with the production of anti-inflammatory cytokines and tolerogenic antigen presentation to effector T-cells. As the understanding of allergic contact dermatitis continues to improve, this will

  4. Psoriasis and Contact Sensitivitiy

    Directory of Open Access Journals (Sweden)

    Deniz Arlı

    2013-03-01

    Full Text Available Objective: The aim of this study was to investigate the frequency of contact sensitivity in patients with psoriasis, whether there was an association between clinical types and contact sensitivity, whether patch test is a factor that causes Koebner reaction and frequency of contact sensitivity against commonly used topical corticosteroids. Methods: Fifty patients with psoriasis and 50 healthy volunteers were included in this study and ‘European standard series' and test units of active ingredients of some corticosteroids were performed on their upper back. The patches were read on hours 24, 48 and on day 7 in order to detect delayed allergic reactions and also Koebner reaction. The results of both groups were compared by using chi-square test. Results: At the end of the patch test allergic reaction was observed in 7 of 50 (14% patients with psoriasis and 12 of 50 (24% healthy volunteers. There was no statistically significant difference between allergic reaction of study group and healthy volunteers. There was no statistically significant difference between the clinical types of psoriasis and allergic contact sensitivity. The frequency of reaction increased in individuals having a positive sensitivity history to any substance in both patient and control groups. Reaction to topical steroids was not seen in any patients. Koebner phenomenon due to patch test was also not seen in any patients. Conclusion: We did not show any association between psoriasis and contact sensitivity in this study. We believe that contact allergens should be determined by using patch test in psoriatic patients with a positive history to any substance.

  5. (AJST) THE INFLUENCE OF PH AND ADSORBENT ...

    African Journals Online (AJOL)

    Lead readily bioaccumulates in the human-rich surface layer of the soils due to its ... soil and its surface chemistry affects the distribution of ..... the metal loading concentrations or volume, the contact time and ... reaction (30) rather than diffusion process. There is a ..... and in measurement of specific surface areas of solids”.

  6. Six challenges in measuring contact networks for use in modelling

    Directory of Open Access Journals (Sweden)

    K. Eames

    2015-03-01

    Full Text Available Contact networks are playing an increasingly important role in epidemiology. A contact network represents individuals in a host population as nodes and the interactions among them that may lead to the transmission of infection as edges. New avenues for data collection in recent years have afforded us the opportunity to collect individual- and population-scale information to empirically describe the patterns of contact within host populations. Here, we present some of the current challenges in measuring empirical contact networks. We address fundamental questions such as defining contact; measurement of non-trivial contact properties; practical issues of bounding measurement of contact networks in space, time and scope; exploiting proxy information about contacts; dealing with missing data. Finally, we consider the privacy and ethical issues surrounding the collection of contact network data.

  7. Critical Points of Contact

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Morelli, Nicola

    2011-01-01

    where the networks meet and establish contact. Thus we argue for the usefulness of the notion of Critical Point of Contact (CPC) to deepen our understanding of the actual life within networks. En route to this notion we draw upon theories within as diverse realms such as interaction design, service...... design, geography, and mobility studies. After the introduction in section we develop and define the notion of CPC based upon a broad set of disciplines and theories. We illustrate the usefulness of the notion within the field of mobility in the network city and within the field of service design...

  8. Contact angle of unset elastomeric impression materials.

    Science.gov (United States)

    Menees, Timothy S; Radhakrishnan, Rashmi; Ramp, Lance C; Burgess, John O; Lawson, Nathaniel C

    2015-10-01

    Some elastomeric impression materials are hydrophobic, and it is often necessary to take definitive impressions of teeth coated with some saliva. New hydrophilic materials have been developed. The purpose of this in vitro study was to compare contact angles of water and saliva on 7 unset elastomeric impression materials at 5 time points from the start of mixing. Two traditional polyvinyl siloxane (PVS) (Aquasil, Take 1), 2 modified PVS (Imprint 4, Panasil), a polyether (Impregum), and 2 hybrid (Identium, EXA'lence) materials were compared. Each material was flattened to 2 mm and a 5 μL drop of distilled water or saliva was dropped on the surface at 25 seconds (t0) after the start of mix. Contact angle measurements were made with a digital microscope at initial contact (t0), t1=2 seconds, t2=5 seconds, t3=50% working time, and t4=95% working time. Data were analyzed with a generalized linear mixed model analysis, and individual 1-way ANOVA and Tukey HSD post hoc tests (α=.05). For water, materials grouped into 3 categories at all time-points: the modified PVS and one hybrid material (Identium) produced the lowest contact angles, the polyether material was intermediate, and the traditional PVS materials and the other hybrid (EXA'lence) produced the highest contact angles. For saliva, Identium, Impregum, and Imprint 4 were in the group with the lowest contact angle at most time points. Modified PVS materials and one of the hybrid materials are more hydrophilic than traditional PVS materials when measured with water. Saliva behaves differently than water in contact angle measurement on unset impression material and produces a lower contact angle on polyether based materials. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  9. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2004-12-01

    Full Text Available Report of PhD Dissertations. Massimo Della Misericordia Divenire comunità. Comuni rurali, poteri signorili, identità sociali in Valtellina e nella montagna lombarda nel tardo medioevo, Tesi di dottorato in Storia medievale (XIV ciclo, Università degli Studi di Torino, 2003   Mariano Dell’Omo Il monastero di S. Liberatore alla Maiella centro dell’irradiazione di Montecassino nell’Abruzzo medievale e moderno. Contributo alla storia dell’organizzazione patrimoniale e della civiltà monastica cassinese nell’Italia centrale attraverso i documenti di S. Liberatore conservati nell’Archivio di Montecassino. Introduzione storica, paleografica e archivistica. Edizione dei documenti più antichi (†798-1000 e regesti di quelli posteriori (1005-1735, Tesi di dottorato in Storia Ecclesiastica, Facoltà di Storia Ecclesiastica, Pontificia Università Gregoriana di Roma,  2004   Giulia Lorenzoni Conquistare e governare la città. Forme di potere e istituzioni nel primo anno della signoria viscontea a Bologna (ottobre 1350-novembre 1351, Tesi di dottorato in Storia medievale (XVI ciclo, Università degli Studi di Bologna, 2004   Federica Monteleone Il viaggio di Carlo Magno in Terra Santa. Un’esperienza di pellegrinaggio nella tradizione europea occidentale, Tesi di dottorato di ricerca in Storia dei centri, delle vie e della cultura dei pellegrinaggi nel Medioevo euro mediterraneo (XV ciclo   Francesca Pucci Donati Fra teorie mediche e pratica quotidiana: i calendari dietetici dell’Occidente latino altomedievale (secoli IX-XI, Tesi di dottorato di ricerca in Storia medievale (XV ciclo, Università degli studi di Bologna, 2004 Alberto Ricciardi L’Epistolario di Lupo di Ferrières come fonte per la storia degli intellettuali nell’età di Carlo il Calvo, Tesi di dottorato in Storia medievale (XV ciclo, Università degli Studi di Bologna, 2004   Francesco Paolo Terlizzi I trattati dell'Anonimo Normanno: ricerche di ecclesiologia, Tesi

  10. Non-Contact Conductivity Measurement for Automated Sample Processing Systems

    Science.gov (United States)

    Beegle, Luther W.; Kirby, James P.

    2012-01-01

    A new method has been developed for monitoring and control of automated sample processing and preparation especially focusing on desalting of samples before analytical analysis (described in more detail in Automated Desalting Apparatus, (NPO-45428), NASA Tech Briefs, Vol. 34, No. 8 (August 2010), page 44). The use of non-contact conductivity probes, one at the inlet and one at the outlet of the solid phase sample preparation media, allows monitoring of the process, and acts as a trigger for the start of the next step in the sequence (see figure). At each step of the muti-step process, the system is flushed with low-conductivity water, which sets the system back to an overall low-conductivity state. This measurement then triggers the next stage of sample processing protocols, and greatly minimizes use of consumables. In the case of amino acid sample preparation for desalting, the conductivity measurement will define three key conditions for the sample preparation process. First, when the system is neutralized (low conductivity, by washing with excess de-ionized water); second, when the system is acidified, by washing with a strong acid (high conductivity); and third, when the system is at a basic condition of high pH (high conductivity). Taken together, this non-contact conductivity measurement for monitoring sample preparation will not only facilitate automation of the sample preparation and processing, but will also act as a way to optimize the operational time and use of consumables

  11. Quantitative analysis of methacycline hydrochloride by direct potentiometry using the internal solid contact sensor.

    Science.gov (United States)

    Sun, Xian Xiang; Aboul-Enein, Hassan Y

    2007-02-01

    An internal solid contact sensor (ISCS) for the determination of methacycline hydrochloride (MC.Cl), Pt/PPy/PVC(MC-PT), is described, based on the use of conducting poly(pyrrole) (PPy) as solid contact material and MC-phosphotungstate (PT) as the ion exchanger and dibutyl phthalate (DBP) as the plasticizer. A direct potentiometric method for the quantitative analysis of MC.Cl is also described. Under the condition of pH 2.7, the linear concentration range, slope (25 degrees C) and detection limit of the sensor are 6.4 x 1.0(-6) - 3.0 x 1.0(-3) M, 52.4 +/- 0.2 mV/decade and 4.4 x 1.0(-6) M, respectively. The response time is potentiometry. The average recovery and relative standard deviation are 100.1 and 0.7% (n = 4), respectively.

  12. Treatment of linear alkylbenzene sulfonate (LAS) wastewater by internal electrolysis--biological contact oxidation process.

    Science.gov (United States)

    Cao, X Z; Li, Y M

    2011-01-01

    Surfactant wastewater is usually difficult to treat due to its toxicity and poor biodegradability. A separate physico-chemical or biochemical treatment method achieves a satisfactory effect with difficulty. In this study, treatment of the wastewater collected from a daily chemical plant by the combination processes of Fe/C internal electrolysis and biological contact oxidation was investigated. For the internal electrolysis process, the optimal conditions were: pH = 4-5, Fe/C = (10-15):1, air-water ratio = (10-20):1 and hydraulic retention time (HRT)= 2 h. For the biological contact oxidation process, the optimal conditions were: HRT = 12 h, DO = 4.0-5.0 mg/L. Treated by the above combined processes, the effluent could meet the I-grade criteria specified in Integrated Wastewater Discharge Standard of China (GB 8978-1996). The results provide valuable information for full-scale linear alkylbenzene sulfonate wastewater treatment.

  13. ANALYSIS OF POINT CONTACTS SUBJECTED TO A CONCENTRATED NORMAL FORCES

    Directory of Open Access Journals (Sweden)

    Stefan GHIMIȘI

    2016-12-01

    Full Text Available To "non-compliant" contacts in which deformations are sufficiently small compared to the size of bodies, elasticity theory applies to closed contact defined by the contact area. Stresses and displacements in elastic semispaces can cause tractions of the surface, being deducted for the first time by Boussinesq (1885 and Cerruti (1882

  14. Pattern recognition of ocean pH

    Science.gov (United States)

    Parker, Albert

    2016-09-01

    The manuscript shows how the few, scattered, latest measurements of ocean pH lacking a proper spatial and time coverage do not permit a meaningful computation of global trends, as the ocean pH is strongly variable in latitude, longitude and depth and very likely is subject to the multi-decadal oscillations that have been identified in the atmospheric and ocean systems. The proposed mathematical model is based on the assumption that the monthly averaged ocean pH may be described by the superposition of a linear trend and inter-annual, decadal and multi-decadal oscillations, with linear and sinusoidal regression coefficients requiring data that are presently unavailable.

  15. Atmospheric pressure gas chromatography coupled to quadrupole-time of flight mass spectrometry as a tool for identification of volatile migrants from autoadhesive labels used for direct food contact.

    Science.gov (United States)

    Canellas, Elena; Vera, Paula; Nerín, Cristina

    2014-11-01

    Pressure-sensitive adhesives (PSA) are used to manufacture labels that are applied directly on the food. These adhesives could contain not only intentionally added compounds (IAS) to the adhesive formula but also non-intentionally added substances (NIAS), due to the impurities from the raw materials used, decomposition of the initial components or from chemical interactions between them. These compounds could migrate to the food and contaminate it. In this study, gas chromatography coupled with mass spectrometry (GC-MS/Q) and atmospheric pressure gas chromatography coupled to a quadrupole hyphenated to a time of flight mass spectrometer (APGC-MS/Q-TOF) have been used for identification of unknown compounds and NIAS coming from a PSA. Seven compounds were identified by GC-MS/Q, and other eight compounds remained initially unknown. The structure of these eight new compounds was elucidated by working with the spectra obtained by APGC-MS/Q-TOF. Finally, two different migration studies were carried out. The first one with Tenax as solid food simulant in contact with the paper label containing the adhesive and the second one with isooctane filled in a natural pork intestine where the label containing the adhesive was applied on the external side. The results are shown and discussed.

  16. Colored Contact Lens Dangers

    Science.gov (United States)

    ... Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology Job Center © American Academy of ...

  17. Lubrication Of Nonconformal Contacts

    Science.gov (United States)

    Jeng, Yeau-Ren

    1991-01-01

    Report discusses advances in knowledge of lubrication of nonconformal contacts in bearings and other machine elements. Reviews previous developments in theory of lubrication, presents advances in theory of lubrication to determine minimum film thickness, and describes experiments designed to investigate one of regimes of lubrication for ball bearings.

  18. [Contact allergies in musicians].

    Science.gov (United States)

    Gasenzer, E R; Neugebauer, E A M

    2012-12-01

    During the last years, the problem of allergic diseases has increased. Allergies are errant immune responses to a normally harmless substance. In musicians the allergic contact dermatitis to exotic woods is a special problem. Exotic rosewood contains new flavonoids, which trigger an allergic reaction after permanent contact with the instrument. High quality woodwind instruments such as baroque flute or clarinets are made in ebony or palisander because of its great sound. Today instruments for non-professional players are also made in these exotic materials and non-professionals may have the risk to develop contact dermatitis, too. Brass-player has the risk of an allergic reaction to the different metals contained in the metal sheets of modern flutes and brass instruments. Specially nickel and brass alloys are used to product flute tubes or brass instruments. Special problem arises in children: patients who are allergic to plants or foods have a high risk to develop contact dermatitis. Parents don't know the materials of low-priced instruments for beginners. Often unknown cheap woods from exotic areas are used. Low-priced brass instruments contain high amount of brass and other cheap metals. Physicians should advice musician-patients or parents about the risks of the different materials and look for the reason of eczema on mouth, face, or hands.

  19. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Tips & Prevention News Ask an Ophthalmologist Patient Stories Español Eye Health / News Halloween Hazard: The Hidden Dangers ... Decorative Contact Lenses Without a Prescription Leer en Español: Peligros asociados con los lentes de contacto de ...

  20. Irritant contact dermatitis.

    Science.gov (United States)

    Ale, Iris S; Maibach, Howard I

    2014-01-01

    Irritant contact dermatitis (ICD) is the most common form of contact dermatitis. It represents the cutaneous response to the toxic/physical effects of a wide variety of environmental agents. Nowadays, it is recognized that irritancy does not represent a single monomorphous entity but rather a complex biologic syndrome with diverse pathophysiology and clinical manifestations. The clinical presentation is highly variable depending on several factors, including properties and strength of the irritant, dose, duration and frequency of exposure, environmental factors, and skin susceptibility. The pathophysiological mechanism depends on activation of the innate immune system and involves skin barrier disruption, cellular changes, and release of proinflammatory mediators that directly recruit and activate T lymphocytes. The diagnosis of irritant contact dermatitis is often clinical, and involves a comprehensive history and examination, as well as the exclusion of allergic contact dermatitis with patch testing. Recent advances in understanding the pathogenesis as well as better awareness of the clinical significance of ICD will lead to a improved care for our patients.

  1. Lettuce contact allergy

    DEFF Research Database (Denmark)

    Paulsen, Evy; Andersen, Klaus E

    2016-01-01

    Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present...

  2. [Current contact allergens].

    Science.gov (United States)

    Geier, J; Uter, W; Lessmann, H; Schnuch, A

    2011-10-01

    Ever-changing exposure to contact allergens, partly due to statutory directives (e.g. nickel, chromate, methyldibromo glutaronitrile) or recommendations from industrial associations (e.g. hydroxyisohexyl 3-cyclohexene carboxaldehyde), requires on-going epidemiologic surveillance of contact allergy. In this paper, the current state with special focus in fragrances and preservatives is described on the basis of data of the Information Network of Departments of Dermatology (IVDK) of the year 2010. In 2010, 12,574 patients were patch tested in the dermatology departments belonging to the IVDK. Nickel is still the most frequent contact allergen. However the continuously improved EU nickel directive already has some beneficial effect; sensitization frequency in young women is dropping. In Germany, chromate-reduced cement has been in use now for several years, leading to a decline in chromate sensitization in brick-layers. Two fragrance mixes are part of the German baseline series; they are still relevant. The most important fragrances in these mixes still are oak moss absolute and hydroxyisohexyl 3-cyclohexene carboxaldehyde. However, in relation to these leading allergens, sensitization frequency to other fragrances contained in the mixes seems to be increasing. Among the preservatives, MCI/MI has not lost its importance as contact allergen, in contrast to MDBGN. Sources of MCI/MI sensitization obviously are increasingly found in occupational context. Methylisothiazolinone is a significant allergen in occupational settings, and less frequently in body care products.

  3. The Nuclear Contact Exists

    CERN Document Server

    Hen, O; Piasetzky, E; Miller, G A; Sargsian, M M

    2014-01-01

    Many-body systems of strongly interacting Fermions are ubiquitous in nature, ranging from High-Tc superconductors and ultra-cold atomic gases to atomic nuclei and neutron stars. Theoretical predictions, recently verified by measurements on ultra-cold atomic gases, show that under certain conditions the universal behavior of systems composed of two kinds of fermions can be described using a single parameter, simply called the contact, which is a measure of the number of different-fermion pairs in close proximity. This paper discusses the relevance of the contact for very different systems: atomic nuclei, made of strongly-interacting neutrons and protons. Here we show that the high-momentum distributions of protons and neutrons in nuclei, dominated by correlated proton-neutron pairs mainly in a spin-triplet state, have the same momentum dependence as those of cold atoms, with a strength described by the contact. We use high-energy electron scattering data to extract a value for the nuclear contact consistent wi...

  4. Thermal Contact Conductance

    Science.gov (United States)

    Salerno, Louis J.; Kittel, Peter

    1997-01-01

    The performance of cryogenic instruments is often a function of their operating temperature. Thus, designers of cryogenic instruments often are required to predict the operating temperature of each instrument they design. This requires accurate thermal models of cryogenic components which include the properties of the materials and assembly techniques used. When components are bolted or otherwise pressed together, a knowledge of the thermal performance of such joints are also needed. In some cases, the temperature drop across these joints represents a significant fraction of the total temperature difference between the instrument and its cooler. While extensive databases exist on the thermal properties of bulk materials, similar databases for pressed contacts do not. This has often lead to instrument designs that avoid pressed contacts or to the over-design of such joints at unnecessary expense. Although many people have made measurements of contact conductances at cryogenic temperatures, this data is often very narrow in scope and even more often it has not been published in an easily retrievable fashion, if published at all. This paper presents a summary of the limited pressed contact data available in the literature.

  5. Language Contact and Bilingualism

    NARCIS (Netherlands)

    Appel, René; Muysken, Pieter

    2006-01-01

    What happens - sociologically, linguistically, educationally, politically - when more than one language is in regular use in a community? How do speakers handle these languages simultaneously, and what influence does this language contact have on the languages involved? Although most people in the w

  6. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... person. Get follow up exams with your eye care provider. If you notice redness, swelling, excessive discharge, pain or discomfort from wearing contact lenses, remove the lenses and seek immediate medical attention from an ophthalmologist. Related resources: Learn how ...

  7. Contact allergy to cosmetics

    DEFF Research Database (Denmark)

    Held, E; Johansen, J D; Agner, T

    1999-01-01

    .4%) had doubtfully positive reaction(s) and 31 (5.8%) had irritant reaction(s). Skin-care products were tested most frequently and were also found to cause most positive, doubtfully positive and irritant reactions, 80% of the patients with positive reactions to their own products had no history of contact...

  8. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... EyeSmart videos on your website . Printable posters . Promotional materials for eye health observances. EyeSmart resources are also available in Spanish . Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs ...

  9. [Contact allergies in medical occupations].

    Science.gov (United States)

    Rustemeyer, T; Pilz, B; Frosch, P J

    1994-12-01

    Based on reports in the literature, data from the information network of German dermatology centres (Informationsverbund Dermatologischer Kliniken) and the authors own findings, a review is presented on prevalence, clinical picture and causative agents of contact allergic dermatoses in health care professions. In 1991 the proportion of suspected occupational diseases in the health care professions (including hairdressers) represented by cases of dermatitis, as reported to the responsible insurance institution, reached 72% of the total for the year (7287 out of 10127). Every 20th to 40th case was recognized as an occupational dermatosis according to German law. Accurate figures on incidence are scarce; for dentists an incidence of 0.11% has been calculated. The risk of developing occupational hand eczema has been shown to be at least three times higher for nurses than for other so-called dry professions. For persons engaged in the personal care of the ill and the elderly, relevant occupational allergens were found to be benzalkonium chloride and aldehydes in disinfectants, as well as rubber accelerators such as thiuram mix. Latex contact urticaria has increasing significance for medical personnel, with prevalence rates of sensitization between 4.5% and 10.7%. Among physicians, contact allergies to thiuram mix were found to be dominant (12.9%). For surgeons and orthopaedic surgeons, methyl methacrylate as a constituent of bone cement is of great importance. Various esters of acrylic acid and methacrylic acid are important sensitizers in the dental professions, particularly in heavily exposed dental laboratory technicians. Only a few gloves protect against these types of sensitizers. Sensitizations by medicaments can be avoided in most cases by reducing direct skin contact, as practiced with penicillin or ispaghula powder. Strategies of prevention include information of atopics regarding the increase in occupational dermatitis, the regular use of barrier creams

  10. Duality based contact shape optimization

    DEFF Research Database (Denmark)

    Vondrák, Vít; Dostal, Zdenek; Rasmussen, John

    2001-01-01

    An implementation of semi-analytic method for the sensitivity analysis in contact shape optimization without friction is described. This method is then applied to the contact shape optimization.......An implementation of semi-analytic method for the sensitivity analysis in contact shape optimization without friction is described. This method is then applied to the contact shape optimization....

  11. Electroless Nickel Deposition: An Alternative for Graphene Contacting.

    Science.gov (United States)

    Popescu, Sinziana M; Barlow, Anders J; Ramadan, Sami; Ganti, Srinivas; Ghosh, Biswajit; Hedley, John

    2016-11-16

    We report the first investigation into the potential of electroless nickel deposition to form ohmic contacts on single layer graphene. To minimize the contact resistance on graphene, a statistical model was used to improve metal purity, surface roughness, and coverage of the deposited film by controlling the nickel bath parameters (pH and temperature). The metalized graphene layers were patterned using photolithography and contacts deposited at temperatures as low as 60 °C. The contact resistance was 215 ± 23 Ω over a contact area of 200 μm × 200 μm, which improved upon rapid annealing to 107 ± 9 Ω. This method shows promise toward low-cost and large-scale graphene integration into functional devices such as flexible sensors and printed electronics.

  12. Contact angle hysteresis at the nanometer scale.

    Science.gov (United States)

    Delmas, Mathieu; Monthioux, Marc; Ondarçuhu, Thierry

    2011-04-01

    Using atomic force microscopy with nonconventional carbon tips, the pinning of a liquid contact line on individual nanometric defects was studied. This mechanism is responsible for the occurrence of the contact angle hysteresis. The presence of weak defects which do not contribute to the hysteresis is evidenced for the first time. The dissipated energy associated with strong defects is also measured down to values in the range of kT, which correspond to defect sizes in the order of 1 nm.

  13. Modelling of time resolved and long contact time dissolution studies of spent nuclear fuel in 10 mM carbonate solution - A comparison between two different models and experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Eriksen, Trygve E. [School of Chemical Science and Engineering, Nuclear Chemistry, Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Jonsson, Mats [School of Chemical Science and Engineering, Nuclear Chemistry, Royal Institute of Technology, SE-100 44 Stockholm (Sweden)], E-mail: matsj@nuchem.kth.se; Merino, Juan [Enviros Spain S.L., Pg. de Rubi' , 29-31, E-08197 Valldoreix (Spain)

    2008-04-30

    Using two different models, radiation induced dissolution of spent UO{sub 2} fuel has been simulated. One of the models is conventional homogeneous radiolysis simulations where two different geometrical constraints were used and the second model is the recently developed steady-state model. The results of the simulations are compared to each other and to experimental results from spent fuel leaching experiments performed in carbonate containing aqueous solution under Ar-atmosphere. The influence of radiolytically produced H{sub 2} is incorporated (on the basis of a recently suggested mechanism) in both models and this reproduces the experimentally observed inhibition of spent fuel dissolution fairly well. The conventional radiolysis model reproduces the experimental concentrations of the radiolysis products H{sub 2} and O{sub 2} very well while it fails to reproduce the experimental H{sub 2}O{sub 2} concentration. The reasons for this are discussed. The general trend in uranium concentration as a function of time is reproduced by both the conventional radiolysis model and the steady-state model. The conventional radiolysis model (in which the radiation dose is homogeneously distributed in the whole liquid volume) underestimates the uranium concentration while the steady-state model, which represents the worst case scenario, overestimates the concentrations to some extent. When applying the conventional radiolysis model, assuming that all the radiation energy is deposited within 40 {mu}m from the fuel surface, the uranium concentrations during the initial part of the experiments are reproduced quantitatively. The differences between the models and the applicability of the models are discussed in some detail.

  14. Modelling of time resolved and long contact time dissolution studies of spent nuclear fuel in 10 mM carbonate solution A comparison between two different models and experimental data

    Science.gov (United States)

    Eriksen, Trygve E.; Jonsson, Mats; Merino, Juan

    2008-04-01

    Using two different models, radiation induced dissolution of spent UO 2 fuel has been simulated. One of the models is conventional homogeneous radiolysis simulations where two different geometrical constraints were used and the second model is the recently developed steady-state model. The results of the simulations are compared to each other and to experimental results from spent fuel leaching experiments performed in carbonate containing aqueous solution under Ar-atmosphere. The influence of radiolytically produced H 2 is incorporated (on the basis of a recently suggested mechanism) in both models and this reproduces the experimentally observed inhibition of spent fuel dissolution fairly well. The conventional radiolysis model reproduces the experimental concentrations of the radiolysis products H 2 and O 2 very well while it fails to reproduce the experimental H 2O 2 concentration. The reasons for this are discussed. The general trend in uranium concentration as a function of time is reproduced by both the conventional radiolysis model and the steady-state model. The conventional radiolysis model (in which the radiation dose is homogeneously distributed in the whole liquid volume) underestimates the uranium concentration while the steady-state model, which represents the worst case scenario, overestimates the concentrations to some extent. When applying the conventional radiolysis model, assuming that all the radiation energy is deposited within 40 μm from the fuel surface, the uranium concentrations during the initial part of the experiments are reproduced quantitatively. The differences between the models and the applicability of the models are discussed in some detail.

  15. Dynamic Model of Contact Interface between Stator and Rotor

    OpenAIRE

    Zhao, Zenghui; Wang, Yuping; Yuan, YiKun; Zhao, Xiangdong

    2013-01-01

    Based on the equivalent principle, a linear spring contact model was established for the friction layer between stator and rotor. Different contact conditions were described by a distance index δ. Detailed analysis of the nonlinear contact behavior especially the static and dynamic slipping was carried on using a space-time equation. A contact deflection angle was proposed to quantitatively express the influence of friction force on the output performance. A more precision simulation model wa...

  16. Broadband electrical characterization of multiwalled carbon nanotubes and contacts.

    Science.gov (United States)

    Rice, Paul; Wallis, T Mitch; Russek, Stephen E; Kabos, Pavel

    2007-04-01

    The electrical response of an individual multiwalled carbon nanotube (MWNT) and its contacts, welded to a coplanar waveguide (CPW), was measured up to 24 GHz using a technique that removes environment effects. This is the first time MWNT contact effects have been systematically isolated from the CPW. Each contact response was quite different and also showed a pronounced sensitivity to ambient light. Adding more contact material clearly changed the high-frequency electrical response and the sensitivity to light.

  17. Electrical contacts principles and applications

    CERN Document Server

    Slade, Paul G

    2013-01-01

    Covering the theory, application, and testing of contact materials, Electrical Contacts: Principles and Applications, Second Edition introduces a thorough discussion on making electric contact and contact interface conduction; presents a general outline of, and measurement techniques for, important corrosion mechanisms; considers the results of contact wear when plug-in connections are made and broken; investigates the effect of thin noble metal plating on electronic connections; and relates crucial considerations for making high- and low-power contact joints. It examines contact use in switch

  18. The impact of national-level interventions to improve hygiene on the incidence of irritant contact dermatitis in healthcare workers: changes in incidence from 1996 to 2012 and interrupted times series analysis.

    Science.gov (United States)

    Stocks, S J; McNamee, R; Turner, S; Carder, M; Agius, R M

    2015-07-01

    Reducing healthcare-associated infections (HCAI) has been a priority in the U.K. over recent decades and this has been reflected in interventions focusing on improving hygiene procedures. To evaluate whether these interventions coincided with an increased incidence of work-related irritant contact dermatitis (ICD) attributed to hand hygiene or/and other hygiene measures in healthcare workers (HCWs). A quasi-experimental (interrupted time series) design was used to compare trends in incidence of ICD in HCWs attributed to hygiene before and after interventions to reduce HCAI with trends in the same periods in control groups (ICD in other workers). Cases of ICD reported to a U.K. surveillance scheme from 1996 to 2012 were analysed. The time periods compared were defined objectively based on the dates of the publication of national evidence-based guidelines, the U.K. Health Act 2006 and the Cleanyourhands campaign. The reported incidence of ICD in HCWs attributed to hygiene has increased steadily from 1996 to 2012 [annual incidence rate ratio (95% confidence interval): hand hygiene only 1.10 (1.07-1.12); all hygiene 1.05 (1.03-1.07)], whereas the incidence in other workers is declining. An increase in incidence of ICD in HCWs attributed to hand hygiene was observed at the beginning of the Cleanyourhands campaign. The increasing incidence of ICD in HCWs combined with the popularity of interventions to reduce HCAI warrants increased efforts towards identifying products and implementing practices posing the least risk of ICD. © 2015 British Association of Dermatologists.

  19. Allergic contact dermatitis in children.

    Science.gov (United States)

    Fontana, E; Belloni Fortina, A

    2014-12-01

    Allergic contact dermatitis is an inflammatory skin disease (delayed type hypersensitivity reaction) that accounts for up to 20% of all childhood dermatitis. Allergic contact dermatitis represents a clinical manifestation of contact sensitization and usually occurs at skin sites that have come into contact with the allergen. The clinical features of allergic contact dermatitis are itchy eczematous lesions. Prevalence of contact sensitization varies between 27% and 96% of children with suspected contact dermatitis. The relationship between contact sensitization and atopic dermatitis has been widely discussed but only conflicting data have been reported. Epicutaneous patch testing is the gold standard for the diagnosis of allergic contact dermatitis. The most common allergens detected in children are: metals, topical medicaments, fragrances, and preservatives. The first line management of allergic contact dermatitis in children is to avoid the offending allergens identified with the patch test and a topical corticosteroid therapy.

  20. Nonlinear dynamics of incommensurately contacting surfaces : a model study

    NARCIS (Netherlands)

    Consoli, Luca

    2002-01-01

    This PhD thesis is about the nonlinear dynamics of contacting surfaces. More specifically, it deals with the problem of modelling at the microscopic level some of the contributions that lead to the macroscopic effect of dry sliding friction. In chapter 1, we try to give an overview of the physical q

  1. [Contact dermatitis from Agave americana].

    Science.gov (United States)

    de la Cueva, Pablo; González-Carrascosa, Mateo; Campos, Minia; Leis, Vicente; Suárez, Ricardo; Lázaro, Pablo

    2005-10-01

    Numerous plant species and their derivatives can cause skin reactions through a variety of mechanisms: irritative contact dermatitis, allergic contact dermatitis, contact urticaria and photodermatitis. We present a case of irritative contact dermatitis after exposure to the sap of Agave americana. The skin symptoms in this case have only been described on rare occasions; although this condition usually presents with a papulovesicular rash, in this patient it appeared as purpuric lesions in the contact area.

  2. Kinetic study of time-dependent fixation of U{sup VI} on biochar

    Energy Technology Data Exchange (ETDEWEB)

    Ashry, A. [Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, Leicestershire LE12 5RD (United Kingdom); Radiation Protection Department, Nuclear Research Centre, Egyptian Atomic Energy Authority, Cairo (Egypt); Bailey, E.H., E-mail: liz.bailey@nottingham.ac.uk [Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, Leicestershire LE12 5RD (United Kingdom); Chenery, S.R.N. [British Geological Survey, Nicker Hill, Keyworth, Nottingham NG12 5GG (United Kingdom); Young, S.D. [Division of Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, Leicestershire LE12 5RD (United Kingdom)

    2016-12-15

    Biochar, a by-product from the production of biofuel and syngas by gasification, was tested as a material for adsorption and fixation of U{sup VI} from aqueous solutions. A batch experiment was conducted to study the factors that influence the adsorption and time-dependent fixation on biochar at 20 °C, including pH, initial concentration of U{sup VI} and contact time. Uranium (U{sup VI}) adsorption was highly dependent on pH but adsorption on biochar was high over a wide range of pH values, from 4.5 to 9.0, and adsorption strength was time-dependent over several days. The experimental data for pH > 7 were most effectively modelled using a Freundlich adsorption isotherm coupled to a reversible first order kinetic equation to describe the time-dependent fixation of U{sup VI} within the biochar structure. Desorption experiments showed that U{sup VI} was only sparingly desorbable from the biochar with time and isotopic dilution with {sup 233}U{sup VI} confirmed the low, or time-dependent, lability of adsorbed {sup 238}U{sup VI}. Below pH 7 the adsorption isotherm trend suggested precipitation, rather than true adsorption, may occur. However, across all pH values (4.5-9) measured saturation indices suggested precipitation was possible: autunite below pH 6.5 and either swartzite, liebigite or bayleyite above pH 6.5.

  3. Contact of surfaces and contact characteristics of offset surfaces

    Institute of Scientific and Technical Information of China (English)

    Lixin CAO; Hu GONG; Jian LIU

    2008-01-01

    Based on differential geometry, the contact problems of two surfaces are discussed in this paper. The relationship between the contact status of two sur-faces and that of offset surfaces are also analyzed. For a 5-axis NC machining, some research such as optimization of cutter location and calculation of the geometrical cusp height are important. The research results indicate that the relative normal curvature is an important geometrical invariant for describing the contact state of two surfaces. For point contact two surfaces, the calculation equation for the second order remained error is given. For line contact two surfaces, the condition of the second order line contact is that the principal directions and curvatures of the two surfaces are the same along the contact curve. If two surfaces keep the second order line contact, their two offset surfaces will also keep the second order line contact, and their third order remained errors are also uniform with that of the two offset surfaces.

  4. Resistivity of Rotated Graphite-Graphene Contacts.

    Science.gov (United States)

    Chari, Tarun; Ribeiro-Palau, Rebeca; Dean, Cory R; Shepard, Kenneth

    2016-07-13

    Robust electrical contact of bulk conductors to two-dimensional (2D) material, such as graphene, is critical to the use of these 2D materials in practical electronic devices. Typical metallic contacts to graphene, whether edge or areal, yield a resistivity of no better than 100 Ω μm but are typically >10 kΩ μm. In this Letter, we employ single-crystal graphite for the bulk contact to graphene instead of conventional metals. The graphite contacts exhibit a transfer length up to four-times longer than in conventional metallic contacts. Furthermore, we are able to drive the contact resistivity to as little as 6.6 Ω μm(2) by tuning the relative orientation of the graphite and graphene crystals. We find that the contact resistivity exhibits a 60° periodicity corresponding to crystal symmetry with additional sharp decreases around 22° and 39°, which are among the commensurate angles of twisted bilayer graphene.

  5. PREFACE: Non-contact AFM Non-contact AFM

    Science.gov (United States)

    Giessibl, Franz J.; Morita, Seizo

    2012-02-01

    This special issue is focussed on high resolution non-contact atomic force microscopy (AFM). Non-contact atomic force microscopy was established approximately 15 years ago as a tool to image conducting and insulating surfaces with atomic resolution. Since 1998, an annual international conference has taken place, and although the proceedings of these conferences are a useful source of information, several key developments warrant devoting a special issue to this subject. In the theoretic field, the possibility of supplementing established techniques such as scanning tunneling microscopy (STM) and Kelvin probe microscopy with atomically resolved force micrsoscopy poses many challenges in the calculation of contrast and contrast reversal. The surface science of insulators, self-assembled monolayers and adsorbates on insulators is a fruitful field for the application of non-contact AFM: several articles in this issue are devoted to these subjects. Atomic imaging and manipulation have been pioneered using STM, but because AFM allows the measurement of forces, AFM has had a profound impact in this field as well. Three-dimensional force spectroscopy has allowed many important insights into surface science. In this issue a combined 3D tunneling and force microscopy is introduced. Non-contact AFM typically uses frequency modulation to measure force gradients and was initially used mainly in a vacuum. As can be seen in this issue, frequency modulation is now also used in ambient conditions, allowing better spatial and force resolution. We thank all of the contributors for their time and efforts in making this special issue possible. We are also very grateful to the staff of IOP Publishing for handling the administrative aspects and for steering the refereeing process. Non-contact AFM contents Relation between the chemical force and the tunnelling current in atomic point contacts: a simple model Pavel Jelínek, Martin Ondrácek and Fernando Flores Theoretical simulation of

  6. /Au Back Contacts

    Science.gov (United States)

    Paudel, Naba R.; Compaan, Alvin D.; Yan, Yanfa

    2014-08-01

    We report on the fabrication and characterization of CdTe thin-film solar cells with Cu-free MoO3- x /Au back contacts. CdTe solar cells with sputtered CdTe absorbers of thicknesses from 0.5 to 1.75 μm were fabricated on Pilkington SnO2:F/SnO2-coated soda-lime glasses coated with a 60- to 80-nm sputtered CdS layer. The MoO3- x /Au back contact layers were deposited by thermal evaporation. The incorporation of MoO3- x layer was found to improve the open circuit voltage ( V OC) but reduce the fill factor of the ultrathin CdTe cells. The V OC was found to increase as the CdTe thickness increased.

  7. Neuronal pH regulation

    DEFF Research Database (Denmark)

    Vorstrup, S; Jensen, K E; Thomsen, C

    1989-01-01

    The intracellular pH in the brain was studied in six healthy volunteers before and immediately after the administration of 2 g of acetazolamide. Phosphorus-31 nuclear magnetic resonance spectroscopy by a 1.5 tesla whole-body scanner was used. The chemical shift between the inorganic phosphate...... and the phosphocreatine resonance frequencies was used for indirect assessment of the intracellular pH. The mean baseline intracellular pH was 7.05 +/- 0.04 (SD). The mean pH changes obtained at 15-min intervals within the first hour of acetazolamide administration were -0.03 +/- 0.04 (SD), -0.02 +/- 0.03 (SD), and 0.......00 +/- 0.04 (SD), i.e., no statistically significant pH decrease was observed during the period where extracellular pH is known to drop markedly. Although several factors contribute to the lack of change of the intraneuronal pH, we will discuss that this observation in addition might suggest a direct...

  8. Contact stress sensor

    Science.gov (United States)

    Kotovsky, Jack [Oakland, CA

    2012-02-07

    A contact stress sensor includes one or more MEMS fabricated sensor elements, where each sensor element of includes a thin non-recessed portion, a recessed portion and a pressure sensitive element adjacent to the recessed portion. An electric circuit is connected to the pressure sensitive element. The circuit includes a thermal compensator and a pressure signal circuit element configured to provide a signal upon movement of the pressure sensitive element.

  9. Occupational protein contact dermatitis.

    Science.gov (United States)

    Barbaud, Annick; Poreaux, Claire; Penven, Emmanuelle; Waton, Julie

    2015-01-01

    Occupational contact dermatitis is generally caused by haptens but can also be induced by proteins causing mainly immunological contact urticaria (ICU); chronic hand eczema in the context of protein contact dermatitis (PCD). In a monocentric retrospective study, from our database, only 31 (0.41%) of patients with contact dermatitis had positive skin tests with proteins: 22 had occupational PCD, 3 had non-occupational PCD, 5 occupational ICU and 1 cook had a neutrophilic fixed food eruption (NFFE) due to fish. From these results and analysis of literature, the characteristics of PCD can be summarized as follows. It is a chronic eczematous dermatitis, possibly exacerbated by work, suggestive if associated with inflammatory perionyxix and immediate erythema with pruritis, to be investigated when the patient resumes work after a period of interruption. Prick tests with the suspected protein-containing material are essential, as patch tests have negative results. In case of multisensitisation revealed by prick tests, it is advisable to analyse IgE against recombinant allergens. A history of atopy, found in 56 to 68% of the patients, has to be checked for. Most of the cases are observed among food-handlers but PCD can also be due to non-edible plants, latex, hydrolysed proteins or animal proteins. Occupational exposure to proteins can thus lead to the development of ICU. Reflecting hypersensitivity to very low concentrations of allergens, investigating ICU therefore requires caution and prick tests should be performed with a diluted form of the causative protein-containing product. Causes are food, especially fruit peel, non-edible plants, cosmetic products, latex, animals.

  10. Contact stress sensor

    Science.gov (United States)

    Kotovsky, Jack

    2014-02-11

    A method for producing a contact stress sensor that includes one or more MEMS fabricated sensor elements, where each sensor element of includes a thin non-recessed portion, a recessed portion and a pressure sensitive element adjacent to the recessed portion. An electric circuit is connected to the pressure sensitive element. The circuit includes a pressure signal circuit element configured to provide a signal upon movement of the pressure sensitive element.

  11. Pediatric contact dermatitis.

    Science.gov (United States)

    Sharma, Vinod K; Asati, Dinesh P

    2010-01-01

    Allergic contact dermatitis (ACD) in children, until recently, was considered rare. ACD was considered as a disorder of the adult population and children were thought to be spared due to a lack of exposure to potential allergens and an immature immune system. Prevalence of ACD to even the most common allergens in children, like poison ivy and parthenium, is relatively rare as compared to adults. However, there is now growing evidence of contact sensitization of the pediatric population, and it begins right from early childhood, including 1-week-old neonates. Vaccinations, piercing, topical medicaments and cosmetics in younger patients are potential exposures for sensitization. Nickel is the most common sensitizer in almost all studies pertaining to pediatric contact dermatitis. Other common allergens reported are cobalt, fragrance mix, rubber, lanolin, thiomersol, neomycin, gold, mercapto mix, balsum of Peru and colophony. Different factors like age, sex, atopy, social and cultural practices, habit of parents and caregivers and geographic changes affect the patterns of ACD and their variable clinical presentation. Patch testing should be considered not only in children with lesions of a morphology suggestive of ACD, but in any child with dermatitis that is difficult to control.

  12. Pediatric contact dermatitis

    Directory of Open Access Journals (Sweden)

    Sharma Vinod

    2010-01-01

    Full Text Available Allergic contact dermatitis (ACD in children, until recently, was considered rare. ACD was considered as a disorder of the adult population and children were thought to be spared due to a lack of exposure to potential allergens and an immature immune system. Prevalence of ACD to even the most common allergens in children, like poison ivy and parthenium, is relatively rare as compared to adults. However, there is now growing evidence of contact sensitization of the pediatric population, and it begins right from early childhood, including 1-week-old neonates. Vaccinations, piercing, topical medicaments and cosmetics in younger patients are potential exposures for sensitization. Nickel is the most common sensitizer in almost all studies pertaining to pediatric contact dermatitis. Other common allergens reported are cobalt, fragrance mix, rubber, lanolin, thiomersol, neomycin, gold, mercapto mix, balsum of Peru and colophony. Different factors like age, sex, atopy, social and cultural practices, habit of parents and caregivers and geographic changes affect the patterns of ACD and their variable clinical presentation. Patch testing should be considered not only in children with lesions of a morphology suggestive of ACD, but in any child with dermatitis that is difficult to control.

  13. Dual contact pogo pin assembly

    Energy Technology Data Exchange (ETDEWEB)

    Hatch, Stephen McGarry

    2016-06-21

    A contact assembly includes a base and a pair of electrical contacts supported by the base. A first end of the first electrical contact corresponds to a first end of the base and is configured to engage a first external conductive circuit element. A first end of the second electrical contact also corresponds to the first end of the base and is configured to engage a second external conductive circuit element. The first contact and the second contact are electrically isolated from one another and configured to compress when engaging an external connector element. The base includes an aperture positioned on a second end of the base outboard of a second end of the first and second electrical contacts. The aperture presents a narrowing shape with a wide mouth distal the electrical contacts and a narrow internal through-hole proximate the electrical contacts.

  14. Mechanical Contact Experiments and Simulations

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Martins, P; Zhang, W.

    2011-01-01

    geometries and different materials are analyzed including contact between dissimilar materials. The numerical implementation is performed with a finite element computer program based on the irreducible flow formulation, and contact between deformable objects is modelled by applying the penalty method....... The overall investigation serves for testing and validating the numerical implementation of the mechanical contact, which is one of the main contributions to a system intended for 3D simulation of resistance welding. Correct modelling of contact between parts to be welded, as well as contact with electrodes......, is crucial for satisfactory modelling of the resistance welding process. The resistance heating at the contact interfaces depends on both contact area and pressure, and as the contact areas develop dynamically, the presented tests are relevant for assessing the validity and accuracy of the mechanical contact...

  15. Exploring the Nature of Contact Freezing

    Science.gov (United States)

    Kiselev, A. A.; Hoffmann, N.; Duft, D.; Leisner, T.

    2012-12-01

    The freezing of supercooled water droplets upon contact with aerosol particles (contact nucleation of ice) is the least understood mechanism of ice formation in atmospheric clouds. Although experimental evidences suggest that some aerosols can be better IN in the contact than in the immersion mode (that is, triggering ice nucleation at higher temperature), no final explanation of this phenomena currently exists. On the other hand, the contact freezing is believed to be responsible for the enhanced rate of secondary ice formation occasionally observed in LIDAR measurements in the cold mixed phase clouds. Recently we have been able to show that the freezing of supercooled droplets electrodynamically levitated in the laminar flow containing mineral dust particles (kaolinite) is a process solely governed by a rate of collisions between the supercooled droplet and the aerosol particles. We have shown that the probability of droplet freezing on a single contact with aerosol particle may differ over an order of magnitude for kaolinite particles having different genesis and morphology. In this presentation we extend the study of contact nucleation of ice and compare the IN efficiency measured for DMA-selected kaolinite, illite and hematite particles. We show that the freezing probability increases towards unity as the temperature decreases and discuss the functional form of this temperature dependence. We explore the size dependence of the contact freezing probability and show that it scales with the surface area of the particles, thus resembling the immersion freezing behavior. However, for all minerals investigated so far, the contact freezing has been shown to dominate over immersion freezing on the short experimental time scales. Finally, based on the combined ESEM and electron microprobe analysis, we discuss the significance of particle morphology and variability of chemical composition on its IN efficiency in contact mode.

  16. Sorption of Am(Ⅲ) on Na-bentonite: Effect of pH, ionic strength,temperature and humic acid

    Institute of Scientific and Technical Information of China (English)

    Tao Yu; Wang Suo Wu; Qiao Hui Fan

    2012-01-01

    Sorption of Am(Ⅲ) on Na-bentonite as a function of contact time,pH,ionic strength,humic acid (HA) and temperature was investigated under ambient conditions.The results showed that the sorption was strongly dependent on pH and ionic strength.Am(Ⅲ) sorption can be described well by pseudo-second-order model.The presence of HA takes a positive effect at low pH; but a negative influence under high pH range.Enthalpy,entropy and Gibbs free energy (i.e.,AH0,AS0 and AG0) calculated from sorption isotherms suggested that sorption process of Am(Ⅲ) was spontaneous and endothermic.

  17. Modeling the mobility of uranium from NORM-rich bedrock using multivariate statistical techniques - The mobility of uranium from U-containing bedrock materials as a function of pH: Implications for tunnel construction

    Energy Technology Data Exchange (ETDEWEB)

    Helmers, Tari; Fjermestad, Halldis; Salbu, Brit; Skipperud, Lindis [Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas (Norway); Meland, Sondre; Hagelia, Per [Norwegian Public Roads Administration, P.O. Box 8142, 0033 Oslo (Norway)

    2014-07-01

    According to amendments made to the Norwegian Pollution Control Act in 2011, naturally occurring radioactive material is now to be considered as an environmental contaminant, in addition to organic pollutants and trace metals. Environmental contamination is strongly correlated with the mobility and bioavailability of metals and radionuclides in natural systems. In order to determine the risk of environmental contamination from e.g. uranium (U) in alum shale areas, it is of particular importance to determine the mobility of U and trace metals found in the rock materials and their binding mechanisms. By determining the speciation and mobility of uranium and trace metals, better predictions can be made on the transport of contaminants in the environment from intervention like road and tunnel construction. The substrate media analyzed in this work was collected from a future tunnel construction site that is being built in the Gran municipality on National road Rv4 in Norway. The bedrock in the Gran municipality is rich in U-bearing minerals. Therefore, there is high potential for environmental contamination from the rock material removed for tunnel construction purposes. The present work focuses upon the effects of pH and the contact time (substrate media: solution) on the mobility of uranium. In order to identify the effects of pH and contact time on mobility, sample cores collected from an area rich in alum shale were subjected to an extended leaching experiment. In this experiment, the substrate materials were treated with five different pH solutions and were analyzed for different contact times. In addition, the results were compared to data from a sequential extraction experiment. In the leaching experiment, the mobilization of uranium in all of the substrate material was affected by the pH of solution. All of the samples were capable of quickly buffering pH solutions with a pH as low as 4 to neutral-alkaline conditions, attributed to the carbonate minerals

  18. In vitro synthesis and purification of PhIP-deoxyguanosine and PhIP-DNA oligomer covalent complexes

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, J.

    1994-12-01

    2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a heterocyclic amine compound formed when meats are cooked at high temperatures. PhIP damages DNA by forming covalent complexes with DNA carcinogen. In an effort to understand how the binding of PhIP to DNA may cause cancer, it is important to characterize the structures of PhIP-damaged DNA molecules. Our HPLC data support fluorescence and {sup 32}P Post-labeling studies which indicate the formation of several species of 2{prime}deoxyguanosine-(dG) or oligodeoxynucleotide-PhIP adducts. The reaction of PhIP with dG resulted in a reddish precipitate that was likely the major adduct, N-(deoxyguanosin-8-yl)-PhIP (dG-C8-PhIP) adduct, with a more polar adduct fraction remaining in the supernatant. Reversed-phase HPLC analysis of the adducts in the supernatant revealed the existence of species of much shorter retention times than the dG-C8-PhIP adduct, confirming that these species are more polar than dG-C8-PhIP. At least four adducts were formed in the reaction of PhIP with DNA oligomer. HPLC analysis of the PhIP-DNA oligomer supernatant after butanol extractions revealed four unresolved peaks which spectra had maximum wavelengths between 340 and 360 nm. Though adduct peaks were not completely resolved, there was {approximately}3 minutes interval between the DNA oligomer peak and the adduct peaks. Furthermore, fluorescence emission data of the DNA oligomer-PhIP adduct solution show heterogeneous binding. The more polar PhIP adducts were fraction-collected and their structures will be solved by nuclear magnetic resonance or x-ray crystallography.

  19. Theory of reciprocating contact for viscoelastic solids

    Science.gov (United States)

    Putignano, Carmine; Carbone, Giuseppe; Dini, Daniele

    2016-04-01

    A theory of reciprocating contacts for linear viscoelastic materials is presented. Results are discussed for the case of a rigid sphere sinusoidally driven in sliding contact with a viscoelastic half-space. Depending on the size of the contact, the frequency and amplitude of the reciprocating motion, and on the relaxation time of the viscoelastic body, we establish that the contact behavior may range from the steady-state viscoelastic solution, in which traction forces always oppose the direction of the sliding rigid punch, to a more elaborate trend, which is due to the strong interaction between different regions of the path covered during the reciprocating motion. Practical implications span a number of applications, ranging from seismic engineering to biotechnology.

  20. Contact laser vaporization of the prostate for benign prostatic hypertrophy

    Science.gov (United States)

    Gomella, Leonard G.; Lotfi, M. A.; Milam, Douglas F.; Albala, David; Reagan, Gary

    1994-05-01

    The contact laser applications for the removal of the enlarged prostate are distinctly different than the majority of non-contact Nd:YAG lasers that rely on coagulation necrosis and delayed sloughing. Contact Nd:YAG laser allows cutting, coagulation and vaporization of tissue with minimal penetration beyond the contact surface. Using the contact laser prostatectomy technique, the contact laser probe directly touches and immediately vaporizes the prostatic tissue under the probe. The net result is the immediate removal of the obstructing tissue, in a manner similar to the standard electrosurgical TURP. This immediate removal of tissue offers the patient treated with the contact laser the potential for decreased catheter time and a more rapid resolution of symptoms. Our initial experience suggests that the contact technique may be better suited for the smaller prostate gland (i.e. less than 30 gm). The contact laser may also be used for a procedure termed the `laser assisted TURP': a standard electrosurgical TURP is performed and the contact laser is used for hemostasis. Several investigators have reported non-randomized results of the contact technique with good outcomes. A prospective randomized trial of the contact laser prostatectomy vrs the electrosurgical TURP is underway. The contact laser vaporization of the prostate holds great promise for the treatment of symptomatic benign prostatic hypertrophy: it is virtually bloodless and allows immediate visualization of the TUR defect.

  1. Estimating the relative weights of visual and auditory tau versus heuristic-based cues for time-to-contact judgments in realistic, familiar scenes by older and younger adults.

    Science.gov (United States)

    Keshavarz, Behrang; Campos, Jennifer L; DeLucia, Patricia R; Oberfeld, Daniel

    2017-04-01

    Estimating time to contact (TTC) involves multiple sensory systems, including vision and audition. Previous findings suggested that the ratio of an object's instantaneous optical size/sound intensity to its instantaneous rate of change in optical size/sound intensity (τ) drives TTC judgments. Other evidence has shown that heuristic-based cues are used, including final optical size or final sound pressure level. Most previous studies have used decontextualized and unfamiliar stimuli (e.g., geometric shapes on a blank background). Here we evaluated TTC estimates by using a traffic scene with an approaching vehicle to evaluate the weights of visual and auditory TTC cues under more realistic conditions. Younger (18-39 years) and older (65+ years) participants made TTC estimates in three sensory conditions: visual-only, auditory-only, and audio-visual. Stimuli were presented within an immersive virtual-reality environment, and cue weights were calculated for both visual cues (e.g., visual τ, final optical size) and auditory cues (e.g., auditory τ, final sound pressure level). The results demonstrated the use of visual τ as well as heuristic cues in the visual-only condition. TTC estimates in the auditory-only condition, however, were primarily based on an auditory heuristic cue (final sound pressure level), rather than on auditory τ. In the audio-visual condition, the visual cues dominated overall, with the highest weight being assigned to visual τ by younger adults, and a more equal weighting of visual τ and heuristic cues in older adults. Overall, better characterizing the effects of combined sensory inputs, stimulus characteristics, and age on the cues used to estimate TTC will provide important insights into how these factors may affect everyday behavior.

  2. Total alkalinity, pH, dissolved oxygen, and other variables collected from time series observations using alkalinity titrator, pH electrode, oxygen optode and other instruments in a shallow back reef on Ofu, American Samoa from 2011-11-12 to 2012-03-27 (NCEI Accession 0127952)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package consists of time series of physical and biogeochemical data from 8 locations (8 tubes) in Pool 100 as well as temperature time series from Pool...

  3. pH jump induced α-helix folding.

    Directory of Open Access Journals (Sweden)

    Donten M. L.

    2013-03-01

    Full Text Available pH can be used to impact the folding equilibrium of peptides and proteins. This fact is utilized, similarly to temperature jumps, in pH jump experiments employing laser time-resolved spectroscopy to study the function and structural dynamics of these molecules. Here the application of pH jumps in folding experiments was investigated. Experiments with poly-L-glutamic acid alpha-helix formation shown the critical aspects of pH jump experiments and yielded direct information about the folding kinetics monitored with the amide I IR band.

  4. Tracking the PhD Students' Daily Computer Use

    Science.gov (United States)

    Sim, Kwong Nui; van der Meer, Jacques

    2015-01-01

    This study investigated PhD students' computer activities in their daily research practice. Software that tracks computer usage (Manic Time) was installed on the computers of nine PhD students, who were at their early, mid and final stage in doing their doctoral research in four different discipline areas (Commerce, Humanities, Health Sciences and…

  5. Contextualizing Intergroup Contact: Do Political Party Cues Enhance Contact Effects?

    DEFF Research Database (Denmark)

    Sønderskov, Kim Mannemar; Thomsen, Jens Peter Frølund

    2015-01-01

    political parties on us-them categorizations heightens the awareness of group memberships. This focus in turn enhances the positive intergroup contact effect by stimulating majority members to perceive contacted persons as prototypical outgroup members. A multilevel analysis of 22 countries and almost 37......,000 individuals confirms that the ability of intergroup contact to reduce antiforeigner sentiment increases when political parties focus intensively on immigration issues and cultural differences. Specifically, both workplace contact and interethnic friendship become more effective in reducing antiforeigner...

  6. PhEDEx Data Service

    Science.gov (United States)

    Egeland, Ricky; Wildish, Tony; Huang, Chih-Hao

    2010-04-01

    The PhEDEx Data Service provides access to information from the central PhEDEx database, as well as certificate-authenticated managerial operations such as requesting the transfer or deletion of data. The Data Service is integrated with the "SiteDB" service for fine-grained access control, providing a safe and secure environment for operations. A plug-in architecture allows server-side modules to be developed rapidly and easily by anyone familiar with the schema, and can automatically return the data in a variety of formats for use by different client technologies. Using HTTP access via the Data Service instead of direct database connections makes it possible to build monitoring web-pages with complex drill-down operations, suitable for debugging or presentation from many aspects. This will form the basis of the new PhEDEx website in the near future, as well as providing access to PhEDEx information and certificate-authenticated services for other CMS dataflow and workflow management tools such as CRAB, WMCore, DBS and the dashboard. A PhEDEx command-line client tool provides one-stop access to all the functions of the PhEDEx Data Service interactively, for use in simple scripts that do not access the service directly. The client tool provides certificate-authenticated access to managerial functions, so all the functions of the PhEDEx Data Service are available to it. The tool can be expanded by plug-ins which can combine or extend the client-side manipulation of data from the Data Service, providing a powerful environment for manipulating data within PhEDEx.

  7. Programmable pH buffers

    Energy Technology Data Exchange (ETDEWEB)

    Gough, Dara Van; Huber, Dale L.; Bunker, Bruce C.; Roberts, Mark E.

    2017-01-24

    A programmable pH buffer comprises a copolymer that changes pK.sub.a at a lower critical solution temperature (LCST) in water. The copolymer comprises a thermally programmable polymer that undergoes a hydrophobic-to-hydrophilic phase change at the LCST and an electrolytic polymer that exhibits acid-base properties that are responsive to the phase change. The programmable pH buffer can be used to sequester CO.sub.2 into water.

  8. PhEDEx Data Service

    Energy Technology Data Exchange (ETDEWEB)

    Egeland, Ricky [University of Minnesota, Twin Cities (United States); Wildish, Tony [Princeton University (United States); Huang, Chih-Hao [Fermi National Accelerator Laboratory (United States)

    2010-04-01

    The PhEDEx Data Service provides access to information from the central PhEDEx database, as well as certificate-authenticated managerial operations such as requesting the transfer or deletion of data. The Data Service is integrated with the 'SiteDB' service for fine-grained access control, providing a safe and secure environment for operations. A plug-in architecture allows server-side modules to be developed rapidly and easily by anyone familiar with the schema, and can automatically return the data in a variety of formats for use by different client technologies. Using HTTP access via the Data Service instead of direct database connections makes it possible to build monitoring web-pages with complex drill-down operations, suitable for debugging or presentation from many aspects. This will form the basis of the new PhEDEx website in the near future, as well as providing access to PhEDEx information and certificate-authenticated services for other CMS dataflow and workflow management tools such as CRAB, WMCore, DBS and the dashboard. A PhEDEx command-line client tool provides one-stop access to all the functions of the PhEDEx Data Service interactively, for use in simple scripts that do not access the service directly. The client tool provides certificate-authenticated access to managerial functions, so all the functions of the PhEDEx Data Service are available to it. The tool can be expanded by plug-ins which can combine or extend the client-side manipulation of data from the Data Service, providing a powerful environment for manipulating data within PhEDEx.

  9. A fast impulsive contact suite for rigid body simulation.

    Science.gov (United States)

    Schmidl, Harald; Milenkovic, Victor J

    2004-01-01

    A suite of algorithms is presented for contact resolution in rigid body simulation under the Coulomb friction model: Given a set of rigid bodies with many contacts among them, resolve dynamic contacts (collisions) and static (persistent) contacts. The suite consists of four algorithms: 1) partial sequential collision resolution, 2) final resolution of collisions through the solution of a single convex QP (positive semidefinite quadratic program), 3) resolution of static contacts through the solution of a single convex QP, 4) freezing of "stationary" bodies. This suite can generate realistic-looking results for simple examples yet, for the first time, can also tractably resolve contacts for a simulation as large as 1,000 cubes in an "hourglass." Freezing speeds up this simulation by more than 25 times. Thanks to excellent commercial QP technology, the contact resolution suite is simple to implement and can be "plugged into" any simulation algorithm to provide fast and realistic-looking animations of rigid bodies.

  10. Contact and contagion: Probability of transmission given contact varies with demographic state in bighorn sheep

    Science.gov (United States)

    Manlove, Kezia R.; Cassirer, E. Frances; Plowright, Raina K.; Cross, Paul C.; Hudson, Peter J.

    2017-01-01

    Understanding both contact and probability of transmission given contact are key to managing wildlife disease. However, wildlife disease research tends to focus on contact heterogeneity, in part because the probability of transmission given contact is notoriously difficult to measure. Here, we present a first step towards empirically investigating the probability of transmission given contact in free-ranging wildlife.We used measured contact networks to test whether bighorn sheep demographic states vary systematically in infectiousness or susceptibility to Mycoplasma ovipneumoniae, an agent responsible for bighorn sheep pneumonia.We built covariates using contact network metrics, demographic information and infection status, and used logistic regression to relate those covariates to lamb survival. The covariate set contained degree, a classic network metric describing node centrality, but also included covariates breaking the network metrics into subsets that differentiated between contacts with yearlings, ewes with lambs, and ewes without lambs, and animals with and without active infections.Yearlings, ewes with lambs, and ewes without lambs showed similar group membership patterns, but direct interactions involving touch occurred at a rate two orders of magnitude higher between lambs and reproductive ewes than between any classes of adults or yearlings, and one order of magnitude higher than direct interactions between multiple lambs.Although yearlings and non-reproductive bighorn ewes regularly carried M. ovipneumoniae, our models suggest that a contact with an infected reproductive ewe had approximately five times the odds of producing a lamb mortality event of an identical contact with an infected dry ewe or yearling. Consequently, management actions targeting infected animals might lead to unnecessary removal of young animals that carry pathogens but rarely transmit.This analysis demonstrates a simple logistic regression approach for testing

  11. Ratiometric Imaging of Extracellular pH in Dental Biofilms.

    Science.gov (United States)

    Schlafer, Sebastian; Dige, Irene

    2016-03-09

    The pH in bacterial biofilms on teeth is of central importance for dental caries, a disease with a high worldwide prevalence. Nutrients and metabolites are not distributed evenly in dental biofilms. A complex interplay of sorption to and reaction with organic matter in the biofilm reduces the diffusion paths of solutes and creates steep gradients of reactive molecules, including organic acids, across the biofilm. Quantitative fluorescent microscopic methods, such as fluorescence life time imaging or pH ratiometry, can be employed to visualize pH in different microenvironments of dental biofilms. pH ratiometry exploits a pH-dependent shift in the fluorescent emission of pH-sensitive dyes. Calculation of the emission ratio at two different wavelengths allows determining local pH in microscopic images, irrespective of the concentration of the dye. Contrary to microelectrodes the technique allows monitoring both vertical and horizontal pH gradients in real-time without mechanically disturbing the biofilm. However, care must be taken to differentiate accurately between extra- and intracellular compartments of the biofilm. Here, the ratiometric dye, seminaphthorhodafluor-4F 5-(and-6) carboxylic acid (C-SNARF-4) is employed to monitor extracellular pH in in vivo grown dental biofilms of unknown species composition. Upon exposure to glucose the dye is up-concentrated inside all bacterial cells in the biofilms; it is thus used both as a universal bacterial stain and as a marker of extracellular pH. After confocal microscopic image acquisition, the bacterial biomass is removed from all pictures using digital image analysis software, which permits to exclusively calculate extracellular pH. pH ratiometry with the ratiometric dye is well-suited to study extracellular pH in thin biofilms of up to 75 µm thickness, but is limited to the pH range between 4.5 and 7.0.

  12. Sequential dual Kalman filtering approach for non-contact temperature measurement in real-time PCR instrument%串联双卡尔曼滤波器在PCR非接触测温中的应用

    Institute of Scientific and Technical Information of China (English)

    陈旭海; 杜民

    2011-01-01

    传统PCR仪对试剂样品进行接触式测温时,存在测量迟滞大、无法直接测量试剂温度以及只能测量局部点温度的缺点,采用红外温度传感器对样品进行非接触测量可以克服以上局限.但红外温度传感器测量噪声较大,为此提出一种串联式双卡尔曼滤波算法来对红外温度传感器采集到的温度数据进行实时滤波.滤波过程中迭代卡尔曼滤波器(IEKF)与线性卡尔曼滤波器(KF)顺序运行,前者利用少量观测数据对热交换模型中的参数进行在线辨识,后者利用辨识后的系统对采样数据进行实时滤波,该算法结合了IEKF非线性估计收敛快与KF计算简单、实时性高的优点.最后建立平滑度、偏差度和准确度指标来评价该算法与KF、EKF、FIR数字滤波器的滤波效果.实验表明,该算法与其他滤波器输出具有相当的平滑度,且偏差度为0.510 6,远小于其他滤波器,准确度指标也由滤波估计前6.8711提高到0.1502.%Traditionally, PCR instrument detects the temperature of reagent by contact measurement, which has several limitations such as thermal hysteresis, reagent contamination and point- measurement. Thus the infra red thermometer is applied to non-contact measure the temperature of reagent. But the infra red thermometer has the defect of relatively high measurement noise. Therefore, we propose a sequential dual Kalman Filters (Seq-DKF), which consists of an Iterated Extended Kalman Filter (IEKF) and a linear Kalman Filter (KF), to remove the measurement noise from infra red thermometer signals in real-time. In this algorithm, IEKF and KF executes sequentially. The former filter rapidly identifies the parameter of heat exchange model by using a small number of observations. The latter filters the temperature signal based on the identified model. After specifying the heat exchange model and the Seq-DKF, we apply, the algorithm to the PCR instrument for testing. Finally, The other

  13. OCCUPATIONAL CONTACT DERMATITIS IN HAIRDRESSERS

    Directory of Open Access Journals (Sweden)

    Komang Ayu Kristiana Dewi K

    2013-07-01

    Full Text Available Occupational skin disease is a skin disease caused or aggravated by work. Occupational skin disease experienced by most hairdressers are contact dermatitis, both irritant and allergic. Some examples of materials that can cause contact dermatitis in hairdressers are nickel, formaldehyde, ammonium thioglycolate, and p-phenylenediaminz. Diagnosis of contact dermatitis in hairdressers enforced through anamnesa, physical examination, and additional tests that are relevant include patch test. The most important treatment is to avoid exposure to irritants and eliminate factors that aggravate. Where appropriate, to address the inflammation can be given topical corticosteroids, such as hydrocortisone. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  14. Dancing in the 'Contact Zone'

    Directory of Open Access Journals (Sweden)

    Monica Wulff

    2006-09-01

    Full Text Available In October 2002 I performed and exhibited Troppo Obscura: A Peepshow of Historical Perversity at the Performance Space as part of the multicultural Arts festival, Carnivale, in Sydney, Australia. Troppo Obscura is a multimedia installation that explores some aspects of the complex relationships between the West and Asia. The work looks at a large range of possibilities, from the colonial gaze through to personal relationships forged through artistic endeavor. This paper—the first of two extended mediations on the topic—focuses on one such personal relationship addressed in the installation, namely that between traditional master mask dancer Ibu Sawitri from Cirebon on the West coast of Java, Indonesia and myself, a Sydney based contemporary dancer and performance artist. Between 1992 and 1999, the year Ibu Sawitri passed away, I spent many long-term visits learning dance and living in Ibu Sawitri’s house in Losari. This essay focuses on Ibu Sawitri’s family and dance background and how she, the younger generation of dancers, the dance context, and the dance itself, have been transformed over time as a result of rapidly changing socio-historical conditions. In the second half of this paper I move the discussion to the broader issues of cross-cultural encounters in what Pratt terms the ‘contact zone’ (1992. This includes looking at dance as an embodied practice and its function in the ‘contact zone’ as well as dealing with Spivak’s debates about the subaltern voice in reference to my telling of Ibu Sawitri’s story, both in the installation and in text. A closer analysis of the dynamics of my dance with Ibu Sawitri in the ‘contact zone’ is addressed here.

  15. Designing pH induced fold switch in proteins

    Science.gov (United States)

    Baruah, Anupaul; Biswas, Parbati

    2015-05-01

    This work investigates the computational design of a pH induced protein fold switch based on a self-consistent mean-field approach by identifying the ensemble averaged characteristics of sequences that encode a fold switch. The primary challenge to balance the alternative sets of interactions present in both target structures is overcome by simultaneously optimizing two foldability criteria corresponding to two target structures. The change in pH is modeled by altering the residual charge on the amino acids. The energy landscape of the fold switch protein is found to be double funneled. The fold switch sequences stabilize the interactions of the sites with similar relative surface accessibility in both target structures. Fold switch sequences have low sequence complexity and hence lower sequence entropy. The pH induced fold switch is mediated by attractive electrostatic interactions rather than hydrophobic-hydrophobic contacts. This study may provide valuable insights to the design of fold switch proteins.

  16. Contact dermatitis in Nigeria.

    Science.gov (United States)

    Olumide, Y M

    1985-05-01

    Nickel is the most important sensitizer in Lagos, with an incidence of 12.3% of 453 patients tested. There was no sex difference, as the wearing of necklaces and bracelets was equally fashionable among both sexes. Housewife eczema is not common, probably because of hardening. Dermatitis from additives in the processing of leather and rubber footwear was the next most common. Chromate sensitivity comes usually from leather or cement. Cultural and climatic factors are mainly responsible for differences in the incidence of contact dermatitis found in Lagos from other countries.

  17. Contact Control, Version 1

    Energy Technology Data Exchange (ETDEWEB)

    2016-07-21

    The contact control code is a generalized force control scheme meant to interface with a robotic arm being controlled using the Robot Operating System (ROS). The code allows the user to specify a control scheme for each control dimension in a way that many different control task controllers could be built from the same generalized controller. The input to the code includes maximum velocity, maximum force, maximum displacement, and a control law assigned to each direction and the output is a 6 degree of freedom velocity command that is sent to the robot controller.

  18. Thermal contact conductance

    CERN Document Server

    Madhusudana, Chakravarti V

    2013-01-01

    The work covers both theoretical and practical aspects of thermal contact conductance. The theoretical discussion focuses on heat transfer through spots, joints, and surfaces, as well as the role of interstitial materials (both planned and inadvertent). The practical discussion includes formulae and data that can be used in designing heat-transfer equipment for a variety of joints, including special geometries and configurations. All of the material has been updated to reflect the latest advances in the field.

  19. Contact dermatitis to methylisothiazolinone*

    Science.gov (United States)

    Scherrer, Maria Antonieta Rios; Rocha, Vanessa Barreto; Andrade, Ana Regina Coelho

    2015-01-01

    Methylisothiazolinone (MI) is a preservative found in cosmetic and industrial products. Contact dermatitis caused by either methylchloroisothiazolinone/methylisothiazolinone (MCI/MI or Kathon CG) or MI has shown increasing frequency. The latter is preferably detected through epicutaneous testing with aqueous MI 2000 ppm, which is not included in the Brazilian standard tray. We describe a series of 23 patients tested using it and our standard tray. A case with negative reaction to MCI/MI and positive to MI is emphasized. PMID:26734880

  20. Contact engineering in organic field-effect transistors

    Directory of Open Access Journals (Sweden)

    Chuan Liu

    2015-03-01

    Full Text Available Organic field-effect transistors (OFETs are promising for numerous potential applications but suffer from poor charge injection, such that their performance is severely limited. Recent efforts in lowering contact resistance have led to significantly improved field-effect mobility of OFETs, up to 100 times higher, as the results of careful choice of contact materials and/or chemical treatment of contact electrodes. Here we review the innovative developments of contact engineering and focus on the mechanisms behind them. Further improvement toward Ohmic contact can be expected along with the rapid advance in material research, which will also benefit other organic and electronic devices.

  1. Gram negative bacteria and contact lens induced acute red eye

    Directory of Open Access Journals (Sweden)

    Sankaridurg Padmaja

    1996-01-01

    Full Text Available Two patients using hydrogel contact lenses on a daily wear schedule slept overnight with the lenses and woke up with a Contact Lens Induced Acute Red Eye (CLARE. The contact lenses recovered aseptically at the time of the event grew significant colonies of Pseudomonas aeruginosa and Aeromonas hydrophila in patient A and Pseudomonas aeruginosa and Serratia liquefaciens from patient B. Similar organisams from the contact lenses were recovered from the lens case and lens care solutions of patient B. In both the patients the condition resolved on discontinuation of lens wear. Patient compliance as a requirement for successful contact lens wear is highlighted with the illustration of these cases.

  2. Allergic contact dermatitis from octylisothiazolinone

    DEFF Research Database (Denmark)

    Mose, Anja Pahlow; Frost, Simon; Ohlund, Ulf;

    2013-01-01

    Octylisothiazolinone is a biocide that has been reported as a moderate, but rare contact allergen.......Octylisothiazolinone is a biocide that has been reported as a moderate, but rare contact allergen....

  3. Contact Center Manager Administration (CCMA)

    Data.gov (United States)

    Social Security Administration — CCMA is the server that provides a browser-based tool for contact center administrators and supervisors. It is used to manage and configure contact center resources...

  4. Optimal contact definition for reconstruction of Contact Maps

    Directory of Open Access Journals (Sweden)

    Stehr Henning

    2010-05-01

    Full Text Available Abstract Background Contact maps have been extensively used as a simplified representation of protein structures. They capture most important features of a protein's fold, being preferred by a number of researchers for the description and study of protein structures. Inspired by the model's simplicity many groups have dedicated a considerable amount of effort towards contact prediction as a proxy for protein structure prediction. However a contact map's biological interest is subject to the availability of reliable methods for the 3-dimensional reconstruction of the structure. Results We use an implementation of the well-known distance geometry protocol to build realistic protein 3-dimensional models from contact maps, performing an extensive exploration of many of the parameters involved in the reconstruction process. We try to address the questions: a to what accuracy does a contact map represent its corresponding 3D structure, b what is the best contact map representation with regard to reconstructability and c what is the effect of partial or inaccurate contact information on the 3D structure recovery. Our results suggest that contact maps derived from the application of a distance cutoff of 9 to 11Å around the Cβ atoms constitute the most accurate representation of the 3D structure. The reconstruction process does not provide a single solution to the problem but rather an ensemble of conformations that are within 2Å RMSD of the crystal structure and with lower values for the pairwise average ensemble RMSD. Interestingly it is still possible to recover a structure with partial contact information, although wrong contacts can lead to dramatic loss in reconstruction fidelity. Conclusions Thus contact maps represent a valid approximation to the structures with an accuracy comparable to that of experimental methods. The optimal contact definitions constitute key guidelines for methods based on contact maps such as structure prediction through

  5. Dynamics of the Molten Contact Line

    Science.gov (United States)

    Sonin, Ain A.; Duthaler, Gregg; Liu, Michael; Torresola, Javier; Qiu, Taiqing

    1999-01-01

    The purpose of this program is to develop a basic understanding of how a molten material front spreads over a solid that is below its melting point, arrests, and freezes. Our hope is that the work will contribute toward a scientific knowledge base for certain new applications involving molten droplet deposition, including the "printing" of arbitrary three-dimensional objects by precise deposition of individual molten microdrops that solidify after impact. Little information is available at this time on the capillarity-driven motion and arrest of molten contact line regions. Schiaffino and Sonin investigated the arrest of the contact line of a molten microcrystalline wax spreading over a subcooled solid "target" of the same material. They found that contact line arrest takes place at an apparent liquid contact angle that depends primarily on the Stefan number S=c(T(sub f) -T(sub t)/L based on the temperature difference between the fusion point and the target temperature, and proposed that contact line arrest occurs when the liquid's dynamic contact angle approaches the angle of attack of the solidification front just behind the contact line. They also showed, however, that the conventional continuum equations and boundary conditions have no meaningful solution for this angle. The solidification front angle is determined by the heat flux just behind the contact line, and the heat flux is singular at that point. By comparing experiments with numerical computations, Schiaffino and Sonin estimated that the conventional solidification model must break down within a distance of order 0.1 - 1 microns of the contact line. The physical mechanism for this breakdown is as yet undetermined, and no first-principles theory exists for the contact angle at arrest. Schiaffino and Sonin also presented a framework for understanding how to moderate Weber number molten droplet deposition in terms of similarity laws and experimentation. The study is based on experiments with three molten

  6. Systemic contact dermatitis

    Directory of Open Access Journals (Sweden)

    Daria Nowak

    2016-02-01

    Full Text Available Systemic contact dermatitis (SCD is a skin inflammation occurring in a patient after systemic administration of a hapten, which previously caused an allergic contact skin reaction in the same person. Most frequently, hypersensitivity reactions typical for SCD occur after absorption of haptens with food or inhalation. Haptens occur mainly in the forms of metals and compounds present in natural resins, preservatives, food thickeners, flavorings and medicines. For many years, several studies have been conducted on understanding the pathogenesis of SCD in which both delayed type hypersensitivity (type IV and immediate type I are observed. Components of the complement system are also suspected to attend there. Helper T cells (Th (Th1 and Th2, cytotoxic T lymphocytes (Tc, and NK cells play a crucial role in the pathogenesis of SCD. They secrete a number of pro-inflammatory cytokines. In addition, regulatory T cells (Tregs have an important role. They control and inhibit activity of the immune system during inflammation. Tregs release suppressor cytokines and interact directly with a target cell through presentation of immunosuppressive particles at the cell surface. Diagnostic methods are generally the patch test, oral provocation test, elimination diet and lymphocyte stimulation test. There are many kinds of inflammatory skin reactions caused by systemic haptens’ distribution. They are manifested in a variety of clinical phenotypes of the disease.

  7. [Systemic contact dermatitis].

    Science.gov (United States)

    Nowak, Daria; Gomułka, Krzysztof; Dziemieszonek, Paulina; Panaszek, Bernard

    2016-02-25

    Systemic contact dermatitis (SCD) is a skin inflammation occurring in a patient after systemic administration of a hapten, which previously caused an allergic contact skin reaction in the same person. Most frequently, hypersensitivity reactions typical for SCD occur after absorption of haptens with food or inhalation. Haptens occur mainly in the forms of metals and compounds present in natural resins, preservatives, food thickeners, flavorings and medicines. For many years, several studies have been conducted on understanding the pathogenesis of SCD in which both delayed type hypersensitivity (type IV) and immediate type I are observed. Components of the complement system are also suspected to attend there. Helper T cells (Th) (Th1 and Th2), cytotoxic T lymphocytes (Tc), and NK cells play a crucial role in the pathogenesis of SCD. They secrete a number of pro-inflammatory cytokines. In addition, regulatory T cells (Tregs) have an important role. They control and inhibit activity of the immune system during inflammation. Tregs release suppressor cytokines and interact directly with a target cell through presentation of immunosuppressive particles at the cell surface. Diagnostic methods are generally the patch test, oral provocation test, elimination diet and lymphocyte stimulation test. There are many kinds of inflammatory skin reactions caused by systemic haptens' distribution. They are manifested in a variety of clinical phenotypes of the disease.

  8. Systemic contact dermatitis

    Directory of Open Access Journals (Sweden)

    Daria Nowak

    2016-02-01

    Full Text Available Systemic contact dermatitis (SCD is a skin inflammation occurring in a patient after systemic administration of a hapten, which previously caused an allergic contact skin reaction in the same person. Most frequently, hypersensitivity reactions typical for SCD occur after absorption of haptens with food or inhalation. Haptens occur mainly in the forms of metals and compounds present in natural resins, preservatives, food thickeners, flavorings and medicines. For many years, several studies have been conducted on understanding the pathogenesis of SCD in which both delayed type hypersensitivity (type IV and immediate type I are observed. Components of the complement system are also suspected to attend there. Helper T cells (Th (Th1 and Th2, cytotoxic T lymphocytes (Tc, and NK cells play a crucial role in the pathogenesis of SCD. They secrete a number of pro-inflammatory cytokines. In addition, regulatory T cells (Tregs have an important role. They control and inhibit activity of the immune system during inflammation. Tregs release suppressor cytokines and interact directly with a target cell through presentation of immunosuppressive particles at the cell surface. Diagnostic methods are generally the patch test, oral provocation test, elimination diet and lymphocyte stimulation test. There are many kinds of inflammatory skin reactions caused by systemic haptens’ distribution. They are manifested in a variety of clinical phenotypes of the disease.

  9. Dynamic contact angle analysis of silicone hydrogel contact lenses.

    Science.gov (United States)

    Read, Michael Leonard; Morgan, Philip Bruce; Kelly, Jeremiah Michael; Maldonado-Codina, Carole

    2011-07-01

    Contact angle measurements are used to infer the clinical wetting characteristics of contact lenses. Such characterization has become more commonplace since the introduction of silicone hydrogel contact lens materials, which have been associated with reduced in vivo wetting due to the inclusion of siloxane-containing components. Using consistent methodology and a single investigator, advancing and receding contact angles were measured for 11 commercially available silicone hydrogel contact lens types with a dynamic captive bubble technique employing customized, fully automated image analysis. Advancing contact angles were found to range between 20° and 72° with the lenses falling into six statistically discrete groupings. Receding contact angles fell within a narrower range, between 17° and 22°, with the lenses segregated into three groups. The relationship between these laboratory measurements and the clinical performance of the lenses requires further investigation.

  10. Testing and Modeling of Contact Problems in Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

    As a part of the efforts towards a professional and reliable numerical tool for resistance welding engineers, this Ph.D. project is dedicated to refining the numerical models related to the interface behavior. An FE algorithm for the contact problems in resistance welding has been developed...... together two or three cylindrical parts as well as disc-ring pairs of dissimilar metals. The tests have demonstrated the effectiveness of the model. A theoretical and experimental study is performed on the contact resistance aiming at a more reliable model for numerical simulation of resistance welding....... The model currently employed is evaluated. It is found that the model may underestimate the constriction resistance because it is based on the assumption of continual contact area. A new model is proposed on the constriction resistance in resistance welding. A parametric study is performed on the contact...

  11. Complications and treatment in early time of posterior chamber phakic intraocular contact lens implantation%有晶体眼后房型人工晶体植入术早期并发症观察及其处理

    Institute of Scientific and Technical Information of China (English)

    吴燕; 罗涛; 蒋炜; 邱敏

    2014-01-01

    目的:观察有晶体眼后房型人工晶体( ICL)植入治疗高度近视早期的并发症及处理情况,并探讨其原因。方法观察在我院行ICL/TICL植入术的患者46例(92眼),在虹膜周切手术和ICL植入手术中及术后半年出现的并发症,记录并发症处理方法以及处理后的情况。结果无1例瞳孔阻滞性青光眼发生,术前虹膜周切后有8眼眼压升高,ICL植入术后有7眼眼压升高,均未超过28 mmHg,未做特殊处理;术前 YAG 激光虹膜周切组虹膜出血及色素播散的发生率明显高于手术虹膜周切组(P<0.05),术中晶体损伤2眼,1眼行透明晶体摘除及人工晶体植入;术后TICL旋转2眼,术后视觉干扰主要表现阴影及眩光各1例,术后视觉心理改变1例。结论 ICL植入治疗高度近视早期并发症少,基本可预防和控制,术后患者满意度极高,该手术方式值得大力推广。%Objective To investigate the complications and outcomes of the treatments in the early time of posterior chamber phakic in-traocular contact lens ( ICL) implantation for the treatment of high myopia, and to analyze the causes. Methods Forty-six patients ( 92 eyes) who underwent ICL/TICL implantations were enrolled in this study. The intraoperative and the postoperative complications in 6 months were observed,at the same time also the treatments and the outcomes were observed. Results None of the patients had a pupillary block. Only 8 eyes in all the patients had an elevated IOP after peripheral iridectomy ( PI) ,and 7 eyes after the ICL implantation,the highest IOP in which was 28 mmHg. No medication was given for treatment. In the YAG PI group,the incidence rate of iris bleeding and pigment dispersion were all higher than that in the YAG PI group (P<0. 05);2 crystalline lens of different patient were damaged intraoperation. Rotation of TICL was observed in 2 eyes. Only 2 individuals of all the patients in this study had complained visual disturbances,which was

  12. Local scale invariances in the bosonic contact and pair-contact processes

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, Florian [Institut fuer Theoretische Physik I, Universitaet Erlangen-Nuernberg, Staudtstrasse 7B3, D-91058 Erlangen (Germany); Laboratoire de Physique des Materiaux , Universite Henri Poincare Nancy I, BP 239, F-54506 Vandoeuvre les Nancy Cedex (France); Stoimenov, Stoimen [Laboratoire de Physique des Materiaux , Universite Henri Poincare Nancy I, BP 239, F-54506 Vandoeuvre les Nancy Cedex (France); Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 1784 Sofia (Bulgaria); Henkel, Malte [Laboratoire de Physique des Materiaux , Universite Henri Poincare Nancy I, BP 239, F-54506 Vandoeuvre les Nancy Cedex (France); Isaac Newton Institute of Mathematical Sciences, 20 Clarkson Road, Cambridge CB3 0EH (United Kingdom)

    2006-04-21

    Local scale invariance for ageing systems without detailed balance is tested through studying the dynamical symmetries of the critical bosonic contact process and the critical bosonic pair-contact process. Their field-theoretical actions can be split into a Schroedinger-invariant term and a pure noise term. It is shown that the two-time response and correlation functions are reducible to certain multipoint response functions which depend only on the Schroedinger-invariant part of the action. For the bosonic contact process, the representation of the Schroedinger group can be derived from the free diffusion equation, whereas for the bosonic pair-contact process, a new representation of the Schroedinger group related to a nonlinear Schroedinger equation with dimensionful couplings is constructed. The resulting predictions of local scale invariance for the two-time responses and correlators are completely consistent with the exactly-known results in both models.

  13. 双断点塑壳断路器触头固有分断时间等计算分析与优化设计%Analysis and Optimization of Inherent Breaking Time for Two-Breakers Molded Case Circuit Breakers Contacts

    Institute of Scientific and Technical Information of China (English)

    周光照

    2016-01-01

    通过对双断点塑壳断路器触头机构的动作过程的受力与运动的详尽分析,应用SolidWorks软件创建了符合实际情况的物理模型与动力学模型,然后应用MATLAB软件,以双断点断路器触头机构相关参数如杠杆弹簧刚度、下连杆长度、动触头质量等多种参数的变化为实例进行优化设计,计算出对应的触头分断速度、固有分断时间、超行程等断路器关键技术数据,同时得到相应情况下的触点P的运动曲线图,为双断点断路器触头机构的优化设计或逆向工程提供依据和参考。%Through a detailed analysis of the force and motion of action about contact mechanism of the two-breakers molded case circuit breaker, creating a kinetic model in line with the actual situation using SolidWorks software, and then using MATLAB software, two-breakers circuit breaker contacts with institutions spring stiffness related parameters such as leverage, changes in the length of the lower link, the movable contact quality and other parameters to optimize the design for instance, calculate the corresponding contact breaking speed, inherent breaking time, travel and other ultra-breaker key technical data, at the same time the corresponding case of contact P of motion graph provide references for optimizing the design or reverse engineering double-break circuit breaker contacts institutions.

  14. The Road to Become a Legitimate Scholar: A Case Study of International PhD Students in Science and Engineering

    Directory of Open Access Journals (Sweden)

    Pia Bøgelund

    2015-11-01

    Full Text Available The purpose of the doctoral education process is to create and legitimize scholarly researchers. This transformation, from student to scholar, is widely discussed in the literature. However, recent rapid changes in university culture have resulted in less time for supervision, stricter completion deadlines, and a greater focus on efficiency and productivity. This has had an impact on this transition process, and this impact has not been widely studied. The aim of this article is to understand the consequences of the current trends for PhD students and the education of PhD students in general. The article is based on interviews with 14 international students from two different research programs at the Faculty of Engineering and Science at Aalborg University in Denmark. The case of international PhD students in a western setting is singled out as a challenging case for becoming a legitimate scholar, since they face the additional challenge of becoming socialised into their new foreign setting. Overall, the study concludes that the transition process of doctoral students is affected by the way different supervisors deal with current university trends and how PhD students fit or do not fit into their knowledge production practices. The study identifies matches or mismatches in a knowledge production perspective, quality of contact, and degree of independence of the PhD student as factors that influence whether a transition process can be marked as sound, troublesome, or lacking. Finally, the study identifies an overall risk of neglecting the more interdependent types of international PhD students. Suggestions are given as how to address this risk.

  15. Equilibrium contact angle or the most-stable contact angle?

    Science.gov (United States)

    Montes Ruiz-Cabello, F J; Rodríguez-Valverde, M A; Cabrerizo-Vílchez, M A

    2014-04-01

    It is well-established that the equilibrium contact angle in a thermodynamic framework is an "unattainable" contact angle. Instead, the most-stable contact angle obtained from mechanical stimuli of the system is indeed experimentally accessible. Monitoring the susceptibility of a sessile drop to a mechanical stimulus enables to identify the most stable drop configuration within the practical range of contact angle hysteresis. Two different stimuli may be used with sessile drops: mechanical vibration and tilting. The most stable drop against vibration should reveal the changeless contact angle but against the gravity force, it should reveal the highest resistance to slide down. After the corresponding mechanical stimulus, once the excited drop configuration is examined, the focus will be on the contact angle of the initial drop configuration. This methodology needs to map significantly the static drop configurations with different stable contact angles. The most-stable contact angle, together with the advancing and receding contact angles, completes the description of physically realizable configurations of a solid-liquid system. Since the most-stable contact angle is energetically significant, it may be used in the Wenzel, Cassie or Cassie-Baxter equations accordingly or for the surface energy evaluation.

  16. Contact and Non-contact Measurements of Grinding Pins

    Directory of Open Access Journals (Sweden)

    Magdziak Marek

    2015-01-01

    Full Text Available The paper presents the results of contact and non-contact measurements of external profiles of selected grinding pins. The measurements were conducted in order to choose the appropriate measuring technique in the case of the considered measurement task. In the case of contact measurements the coordinate measuring machine ACCURA II was applied. The used coordinate measuring machine was equipped with the contact scanning probe VAST XT and the Calypso inspection software. Contact coordinate measurements were performed by using of different measurement strategies. The applied strategies included different scanning velocities and distances between measured points. Non-contact measurements were conducted by means of the tool presetter produced by the Mahr company. On the basis of gained results the guidelines concerning measurements of grinding pins were formulated. The measurements of analyzed grinding pins performed by means of the non-contact measuring system are characterized by higher reproducibility than the contact measurements. The low reproducibility of contact measurements may be connected with the inaccuracy of the selected coordinate measuring machine and the measuring probe, the measurement parameters and environmental conditions in the laboratory where the coordinate measuring machine is located. Moreover, the paper presents the possible application of results of conducted investigations. The results of non-contact measurements can be used in the simulation studies of grinding processes. The simulations may reduce the costs of machining processes.

  17. Reducing contact resistance in graphene devices through contact area patterning.

    Science.gov (United States)

    Smith, Joshua T; Franklin, Aaron D; Farmer, Damon B; Dimitrakopoulos, Christos D

    2013-04-23

    Performance of graphene electronics is limited by contact resistance associated with the metal-graphene (M-G) interface, where unique transport challenges arise as carriers are injected from a 3D metal into a 2D-graphene sheet. In this work, enhanced carrier injection is experimentally achieved in graphene devices by forming cuts in the graphene within the contact regions. These cuts are oriented normal to the channel and facilitate bonding between the contact metal and carbon atoms at the graphene cut edges, reproducibly maximizing "edge-contacted" injection. Despite the reduction in M-G contact area caused by these cuts, we find that a 32% reduction in contact resistance results in Cu-contacted, two-terminal devices, while a 22% reduction is achieved for top-gated graphene transistors with Pd contacts as compared to conventionally fabricated devices. The crucial role of contact annealing to facilitate this improvement is also elucidated. This simple approach provides a reliable and reproducible means of lowering contact resistance in graphene devices to bolster performance. Importantly, this enhancement requires no additional processing steps.

  18. Contact angle and local wetting at contact line.

    Science.gov (United States)

    Li, Ri; Shan, Yanguang

    2012-11-06

    This theoretical study was motivated by recent experiments and theoretical work that had suggested the dependence of the static contact angle on the local wetting at the triple-phase contact line. We revisit this topic because the static contact angle as a local wetting parameter is still not widely understood and clearly known. To further clarify the relationship of the static contact angle with wetting, two approaches are applied to derive a general equation for the static contact angle of a droplet on a composite surface composed of heterogeneous components. A global approach based on the free surface energy of a thermodynamic system containing the droplet and solid surface shows the static contact angle as a function of local surface chemistry and local wetting state at the contact line. A local approach, in which only local forces acting on the contact line are considered, results in the same equation. The fact that the local approach agrees with the global approach further demonstrates the static contact angle as a local wetting parameter. Additionally, the study also suggests that the wetting described by the Wenzel and Cassie equations is also the local wetting of the contact line rather than the global wetting of the droplet.

  19. Mechanical Contact Experiments and Simulations

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Martins, P; Zhang, W.

    2011-01-01

    Mechanical contact is studied under dynamic development by means of a combined numerical and experimental investigation. The experiments are designed to allow dynamical development of non-planar contact areas with significant expansion in all three directions as the load is increased. Different...... geometries and different materials are analyzed including contact between dissimilar materials. The numerical implementation is performed with a finite element computer program based on the irreducible flow formulation, and contact between deformable objects is modelled by applying the penalty method....... The overall investigation serves for testing and validating the numerical implementation of the mechanical contact, which is one of the main contributions to a system intended for 3D simulation of resistance welding. Correct modelling of contact between parts to be welded, as well as contact with electrodes...

  20. Point contacts in encapsulated graphene

    Energy Technology Data Exchange (ETDEWEB)

    Handschin, Clevin [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Swiss Nanoscience Institute, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Fülöp, Bálint; Csonka, Szabolcs [Department of Physics, Budapest University of Technology and Economics and Condensed Matter Research Group of the Hungarian Academy of Sciences, Budafoki ut 8, 1111 Budapest (Hungary); Makk, Péter; Blanter, Sofya; Weiss, Markus; Schönenberger, Christian, E-mail: Christian.Schoenenberger@unibas.ch [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Watanabe, Kenji; Taniguchi, Takashi [National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044 (Japan)

    2015-11-02

    We present a method to establish inner point contacts with dimensions as small as 100 nm on hexagonal boron nitride (hBN) encapsulated graphene heterostructures by pre-patterning the top-hBN in a separate step prior to dry-stacking. 2- and 4-terminal field effect measurements between different lead combinations are in qualitative agreement with an electrostatic model assuming point-like contacts. The measured contact resistances are 0.5–1.5 kΩ per contact, which is quite low for such small contacts. By applying a perpendicular magnetic field, an insulating behaviour in the quantum Hall regime was observed, as expected for inner contacts. The fabricated contacts are compatible with high mobility graphene structures and open up the field for the realization of several electron optical proposals.

  1. Hair dye contact allergy

    DEFF Research Database (Denmark)

    Søsted, Heidi; Rastogi, Suresh Chandra; Andersen, Klaus Ejner

    2004-01-01

    Colouring of hair can cause severe allergic contact dermatitis. The most frequently reported hair dye allergens are p-phenylenediamine (PPD) and toluene-2,5-diamine, which are included in, respectively, the patch test standard series and the hairdressers series. The aim of the present study...... was to identify dye precursors and couplers in hair dyeing products causing clinical hair dye dermatitis and to compare the data with the contents of these compounds in a randomly selected set of similar products. The patient material comprised 9 cases of characteristic clinical allergic hair dye reaction, where...... exposure history and patch testing had identified a specific hair dye product as the cause of the reaction. The 9 products used by the patients were subjected to chemical analysis. 8 hair dye products contained toluene-2,5-diamine (0.18 to 0.98%). PPD (0.27%) was found in 1 product, and m-aminophenol (0...

  2. Contact dermatitis to Alstroemeria.

    Science.gov (United States)

    Santucci, B; Picardo, M; Iavarone, C; Trogolo, C

    1985-04-01

    A study was carried out on 50 workers in a floriculture centre to evaluate the incidence of contact dermatitis to Alstroemeria. 3 subjects gave positive reactions to aqueous and ethanolic extracts of cut flowers, stems and leaves. By column chromatography, the allergen was isolated and its chemical structure identified as 6-tuliposide A by proton magnetic resonance and carbon-13 magnetic resonance. Only 6-tuliposide A was isolated from cut flowers, and this gave positive reactions when patch tested at 0.01%; a-methylene-gamma-butyrolactone at 10(-5) (v/v) was positive in the same 3 subjects. Other lactones (gamma-methylene-gamma-butyrolactone, alantolactone, isoalantolactone) were negative at all concentrations used.

  3. Fragrance contact allergy

    DEFF Research Database (Denmark)

    Johansen, Jeanne D

    2003-01-01

    in the same products. This means that it is difficult to avoid exposure, as products labelled as 'fragrance free' have also been shown to contain fragrance ingredients, either because of the use of fragrance ingredients as preservatives or masking perfumes, or the use of botanicals. About 2500 different...... typically have a history of rash to a fine fragrance or scented deodorants. Chemical analysis has revealed that well known allergens from the fragrance mix are present in 15-100% of cosmetic products, including deodorants and fine fragrances, and most often in combinations of three to four allergens...... fragrance ingredients are currently used in the composition of perfumes and at least 100 of these are known contact allergens. Therefore, it is advisable to supplement standard patch testing with the patient's own stay-on cosmetic products, as well as the fragrance chemical hydroxyisohexyl-3-cyclohexane...

  4. Fragrance contact allergy

    DEFF Research Database (Denmark)

    Johansen, Jeanne D

    2003-01-01

    typically have a history of rash to a fine fragrance or scented deodorants. Chemical analysis has revealed that well known allergens from the fragrance mix are present in 15-100% of cosmetic products, including deodorants and fine fragrances, and most often in combinations of three to four allergens...... in the same products. This means that it is difficult to avoid exposure, as products labelled as 'fragrance free' have also been shown to contain fragrance ingredients, either because of the use of fragrance ingredients as preservatives or masking perfumes, or the use of botanicals. About 2500 different...... fragrance ingredients are currently used in the composition of perfumes and at least 100 of these are known contact allergens. Therefore, it is advisable to supplement standard patch testing with the patient's own stay-on cosmetic products, as well as the fragrance chemical hydroxyisohexyl-3-cyclohexane...

  5. Cosmetic Contact Allergens

    Directory of Open Access Journals (Sweden)

    An Goossens

    2016-02-01

    Full Text Available This article presents trends in the frequency of cosmetics as causal factors of allergic contact dermatitis during a 26-year period in 14,911 patients patch-tested between 1990 and 2014, and discusses the cosmetic allergens identified during the last six years (2010–2015 in 603 patients out of 3105 tested. The data were retrieved from, and evaluated with, a patient database developed in-house. The results show the increasing importance of cosmetic allergies, up to 25% of the patients tested during the last five-year period. As expected, fragrance materials, preservatives, and hair dyes were the most frequent culprits, but a great variety of other allergenic ingredients were involved as well. This underlines the need of additional and extensive patch testing with the patient’s products used and their ingredients.

  6. Mechanoluminescent Contact Type Sensor

    Directory of Open Access Journals (Sweden)

    A. K. Yefremov

    2017-01-01

    Full Text Available Mechanoluminescent sensing elements convert mechanical stress into optical radiation. Advantages of such sensors are the ability to generate an optical signal, solid-state, simple structure, and resistance to electromagnetic interference. Mechanoluminescent sensor implementations can possess the concentrated and distributed sensitivity, thereby allowing us to detect the field of mechanical stresses distributed across the area and in volume. Most modern semiconductor photo-detectors can detect mechanoluminescent radiation, so there are no difficulties to provide its detection when designing the mechanoluminescent sensing devices. Mechanoluminescent substances have especial sensitivity to shock loads, and this effect can be used to create a fuse the structure of which includes a target contact type sensor with a photosensitive actuator. The paper briefly describes the theoretical basics of mechanoluminiscence: a light signal emerges from the interaction of crystalline phosphor luminescence centers with electrically charged dislocations, moving due to the deformation of the crystal. A mathematical model of the mechanoluminescent conversion is represented as a functional interaction between parameters of the mechanical shock excitation and the sensor light emission. Examples of computing the optical mechanoluminescent output signal depending on the duration and peak level of impulse load are given. It is shown that the luminous flux, generated by mechanoluminescent sensing element when there is an ammunition-target collision causes the current emerging in photo-detector (photodiode that is sufficient for a typical actuator of the fuse train to operate. The potential possibility to create a contact target type sensor based on the light-sensitive mechanoluminescent sensor was proved by the calculation and simulation results.

  7. Can dynamic contact angle be measured using molecular modeling?

    Science.gov (United States)

    Malani, Ateeque; Raghavanpillai, Anilkumar; Wysong, Ernest B; Rutledge, Gregory C

    2012-11-02

    A method is presented for determining the dynamic contact angle at the three-phase contact between a solid, a liquid, and a vapor under an applied force, using molecular simulation. The method is demonstrated using a Lennard-Jones fluid in contact with a cylindrical shell of the fcc Lennard-Jones solid. Advancing and receding contact angles and the contact angle hysteresis are reported for the first time by this approach. The increase in force required to wet fully an array of solid cylinders (robustness) with decreasing separation distance between cylinders is evaluated. The dynamic contact angle is characterized by partial slipping of the three phase contact line when a force is applied.

  8. International rigid contact lens prescribing.

    Science.gov (United States)

    Efron, Nathan; Morgan, Philip B; Helland, Magne; Itoi, Motozumi; Jones, Deborah; Nichols, Jason J; van der Worp, Eef; Woods, Craig A

    2010-06-01

    Rigid lenses have been fitted less since the introduction of soft lenses nearly 40 years ago. Data that we have gathered from annual contact lens fitting surveys conducted in Australia, Canada, Japan, the Netherlands, Norway, the UK and the USA between 2000 and 2008 facilitate an accurate characterization of the pattern of the decline of rigid lens fitting during the first decade of this century. There is a trend for rigid lenses to be utilized primarily for refitting those patients who are already successful rigid lens wearers-most typically older females being refit with higher Dk materials. Rigid lenses are generally fitted on a full-time basis (four or more days of wear per week) without a planned replacement schedule. Orthokeratology is especially popular in the Netherlands, but is seldom prescribed in the other countries surveyed.

  9. [Measurement of intracellular pH].

    Science.gov (United States)

    Hanaoka, K; Imai, M; Yoshitomi, K

    1992-09-01

    Since various cellular processes depend on changes in pH, the regulation of intracellular pH (pHi) is important both for the individual cell and for the organism. The mechanisms of the regulation of pHi can be investigated by monitoring pHi. In this report, we discuss the four major techniques available for measuring pHi, which are 1) Distribution of weak acids and bases, 2) pH-sensitive microelectrodes, 3) pH-sensitive dyes, and 4) Nuclear magnetic resonance. Among four techniques, the advantage of the microelectrode approach is that it can monitor membrane potential at the same time and be applied to a single cell. The dye technique is a relative new developing technique, which has lots of advantages. It is easy to use, and is capable of monitoring rapid pHi changes, and being applied to a smaller cell, or a single cell.

  10. Interfacial pH during mussel adhesive plaque formation.

    Science.gov (United States)

    Martinez Rodriguez, Nadine R; Das, Saurabh; Kaufman, Yair; Israelachvili, Jacob N; Waite, J Herbert

    2015-01-01

    Mussel (Mytilus californianus) adhesion to marine surfaces involves an intricate and adaptive synergy of molecules and spatio-temporal processes. Although the molecules, such as mussel foot proteins (mfps), are well characterized, deposition details remain vague and speculative. Developing methods for the precise surveillance of conditions that apply during mfp deposition would aid both in understanding mussel adhesion and translating this adhesion into useful technologies. To probe the interfacial pH at which mussels buffer the local environment during mfp deposition, a lipid bilayer with tethered pH-sensitive fluorochromes was assembled on mica. The interfacial pH during foot contact with modified mica ranged from 2.2 to 3.3, which is well below the seawater pH of ~ 8. The acidic pH serves multiple functions: it limits mfp-Dopa oxidation, thereby enabling the catecholic functionalities to adsorb to surface oxides by H-bonding and metal ion coordination, and provides a solubility switch for mfps, most of which aggregate at pH ≥ 7-8.

  11. Immobilized pH gradients (IPG) simulator--an additional step in pH gradient engineering: I. Linear pH gradients.

    Science.gov (United States)

    Tonani, C; Righetti, P G

    1991-12-01

    A new computer program, called immobilized pH gradients (IPG) simulator, is proposed for calculating and optimizing any recipe for use in isoelectric focusing in immobilized pH gradients. Unlike our previous monoprotic electrolyte gradient simulation (MGS) and polyelectrolyte gradient simulation (PGS) programs, based on minimizing CV(beta), the present program has a target function the minimization of the quadratic moment around zero of the residuals (mu 2). With this algorithm it is possible to formulate IPG recipes which have deviations from linearity well below 1% of the given pH interval (a limit set with the previous MGS and PGS programs), in fact, as small as 0.1-0.2% (in pH units). The new simulator performs 2-3 times better than the previous ones in the pH 4-10 range, and is absolutely necessary when working outside this range, at extreme pH values, where CV(beta) cannot work against the buffering power of bulk water, thus generating pH recipes with huge deviations from linearity. In the latter cases, mu 2 performs 10 times better than CV(beta). When utilizing strong titrants for extended pH intervals, the "all or none" rule has been discovered: such titrants should always be used in tandem, since omission of one of the two at either the acidic or basic extremes produces strongly distorted pH profiles. Our new, most powerful simulator also contains equations for creating nonlinear gradients, notably: concave and convex exponentials and sigmoidal (see the companion paper: Righetti, P. G. and Tonani, C., Electrophoresis 1991, 12, 1021-1027).

  12. Determination of efficiencies, loss mechanisms, and performance degradation factors in chopper controlled dc vehical motors. Section 2: The time dependent finite element modeling of the electromagnetic field in electrical machines: Methods and applications. Ph.D. Thesis

    Science.gov (United States)

    Hamilton, H. B.; Strangas, E.

    1980-01-01

    The time dependent solution of the magnetic field is introduced as a method for accounting for the variation, in time, of the machine parameters in predicting and analyzing the performance of the electrical machines. The method of time dependent finite element was used in combination with an also time dependent construction of a grid for the air gap region. The Maxwell stress tensor was used to calculate the airgap torque from the magnetic vector potential distribution. Incremental inductances were defined and calculated as functions of time, depending on eddy currents and saturation. The currents in all the machine circuits were calculated in the time domain based on these inductances, which were continuously updated. The method was applied to a chopper controlled DC series motor used for electric vehicle drive, and to a salient pole sychronous motor with damper bars. Simulation results were compared to experimentally obtained ones.

  13. A CONTACT SEARCHING ALGORITHM FOR CONTACT-IMPACT PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    Wang Fujun; Cheng Jiangang; Yao Zhenhan

    2000-01-01

    A new contact searching algorithm for contact-impact systems is proposed in this paper. In terms of the cell structure and the linked-list, this algorithm solves the problem of sorting and searching contacts in three dimensions by transforming it to a retrieving process from two one-dimensional arrays, and binary searching is no longer required. Using this algorithm, the cost of contact searching is reduced to the order of O(N) instead of O(Nlog2N) for traditional ones, where N is the node number in the system. Moreover, this algorithm can handle contact systems with arbitrary mesh layouts. Due to the simplicity of this algorithm it can be easily implemented in a dynamic explicit finite element Program. Our numerical experimental result shows that this algorithm is reliable and efficient for contact searching of three dimensional systems.

  14. Media planning by optimizing contact frequencies

    NARCIS (Netherlands)

    N. Piersma (Nanda); S. Kapsenberg; P. Kloprogge; A.P.M. Wagelmans (Albert)

    1998-01-01

    textabstractIn this paper we study a model to estimate the probability that a target group of an advertising campaign is reached by a commercial message a given number of times. This contact frequency distribution is known to be computationally difficult to calculate because of dependence between

  15. Contact dermatitis caused by dimethylfumarate in Argentina.

    Science.gov (United States)

    Lo Balbo, A; Gotelli, M J; Mac Cormack, W P; Kogan, N; Gotelli, C

    2011-07-01

    For the first time in Argentina, we describe an outbreak of contact dermatitis. New pairs of shoes caused intense pruritus, pain, and eruption, followed by edema, blisters, and a severe negative impact on the epidermal barrier of the feet. We identify dimethylfumarate as the causal agent and suggest an analytical method for its fast identification.

  16. Robust Algorithms for Contact Problems with Constitutive Contact Laws

    OpenAIRE

    2016-01-01

    This thesis is concerned with the solution of contact problems with advanced Coulomb friction in the 3D case using the finite element method. A Lagrange multiplier method modelling the contact traction is employed and the contact conditions are enforced in a weak sense leading to a surface-to-surface discretization. Here more precisely the dual mortar method is used allowing for a static condensation of the additional variables in the system before solving without loosing the optimality of...

  17. PhEDEx Data Service

    CERN Document Server

    Egeland, Ricky; Huang, Chih-Hao

    2009-01-01

    The PhEDEx Data Service provides access to information from the central PhEDEx database, as well as certificate-authenticated managerial operations such as requesting the transfer or deletion of data. The Data Service is integrated with the SiteDB service for fine-grained access control, providing a safe and secure environment for operations. A plug-in architecture allows server-side modules to be developed rapidly and easily by anyone familiar with the schema, and can automatically return the data in a variety of formats for use by different client technologies. Using HTTP access via the Data Service instead of direct database connections makes it possible to build monitoring web-pages with complex drill-down operations, suitable for debugging or presentation from many aspects. This will form the basis of the new PhEDEx website in the near future, as well as providing access to PhEDEx information and certificate-authenticated services for other CMS dataflow and workflow management tools such as CRAB, WMCore,...

  18. pH in Action

    NARCIS (Netherlands)

    Tijskens, L.M.M.; Biekman, E.S.A.

    2001-01-01

    Based on fundamental chemical relations, well-established in chemical engineering and chemical technology over almost a century, the effects of pH in food and agricultural products will be deduced for different situations and processes. Based on simple equilibria and dissociation of water, salts, ac

  19. Universal contact-line dynamics at the nanoscale.

    Science.gov (United States)

    Rivetti, Marco; Salez, Thomas; Benzaquen, Michael; Raphaël, Elie; Bäumchen, Oliver

    2015-12-28

    The relaxation dynamics of the contact angle between a viscous liquid and a smooth substrate is studied at the nanoscale. Through atomic force microscopy measurements of polystyrene nanostripes we simultaneously monitor both the temporal evolution of the liquid-air interface and the position of the contact line. The initial configuration exhibits high curvature gradients and a non-equilibrium contact angle that drive liquid flow. Both these conditions are relaxed to achieve the final state, leading to three successive regimes in time: (i) stationary contact line levelling; (ii) receding contact line dewetting; (iii) collapse of the two fronts. For the first regime, we reveal the existence of a self-similar evolution of the liquid interface, which is in excellent agreement with numerical calculations from a lubrication model. For different liquid viscosities and film thicknesses we provide evidence for a transition to dewetting featuring a universal critical contact angle and dimensionless time.

  20. Ratiometric Imaging of Extracellular pH in Dental Biofilms

    DEFF Research Database (Denmark)

    Schlafer, Sebastian; Dige, Irene

    2016-01-01

    The pH in bacterial biofilms on teeth is of central importance for dental caries, a disease with a high worldwide prevalence. Nutrients and metabolites are not distributed evenly in dental biofilms. A complex interplay of sorption to and reaction with organic matter in the biofilm reduces...... the diffusion paths of solutes and creates steep gradients of reactive molecules, including organic acids, across the biofilm. Quantitative fluorescent microscopic methods, such as fluorescence life time imaging or pH ratiometry, can be employed to visualize pH in different microenvironments of dental biofilms....... pH ratiometry exploits a pH-dependent shift in the fluorescent emission of pH-sensitive dyes. Calculation of the emission ratio at two different wavelengths allows determining local pH in microscopic images, irrespective of the concentration of the dye. Contrary to microelectrodes the technique...

  1. Investigation of Delivery Mode and Measuring Time on Neonatal Umbilical Arterial Blood pH Value%分娩方式及测量时间对新生儿脐动脉血pH值影响的探讨

    Institute of Scientific and Technical Information of China (English)

    卢德梅; 柳青叶; 尤小燕; 邹锁芳; 肖乐梅

    2012-01-01

      目的:探讨不同分娩方式不同分析时间对脐血pH值的影响,并研究两者之间的交互作用.方法:严格按照纳入标准选择研究对象,留取3份脐血,每份1 ml,分别于10 min、30 min、50 min时采用ABL77血气分析仪分析剖宫产和顺产产妇的脐血pH值,重复测量设计方差分析判定结果有无差异.结果:剖宫产产妇的脐血pH值高于顺产产妇,差异具有统计学意义(P<0.05).血气分析时间对脐血pH值影响较小.分娩方式和分析时间对脐血pH值影响不存在交互作用.结论:区别对待两种分娩方式的pH值是正确判定新生儿有无宫内窒息的重要前提.%  Objective:To assess whether delivery mode and analysis time can affect cord blood pH values which measured by umbilical cord blood gas analysis and further analyzed if there is interaction between these two factors on pH values.Method:Selected the participants according to the inclusion criteria strictly.Then collected 3 umbilical cord blood for analysis.Analysis of variance by repeated measurement design was used for analyze the differences between different groups.Result:The cord blood pH value for cesarean section pregnant women was higher than spontaneous labor pregnant women(significant at 0.05 level). The analysis time affect cord blood pH value weekly. There was no interaction between delivery mode and analysis time on pH value.Conclusion:It is necessary to distinguish their delivery mode before apply cord blood gas analysis result to diagnose neonatal asphyxia.

  2. Adsorption behavior of methyl orange onto wheat bran: Role of surface and pH

    Directory of Open Access Journals (Sweden)

    Atef S. Alzaydien

    2015-06-01

    Full Text Available This paper deals with the application of wheat bran (WB, an agricultural by-product, for the adsorption of methyl orange (MO from aqueous solution. The characteristics of WS surface, such as surface functional groups, zero of point charge and conductivity were obtained. The removal of MO onto WB from aqueous solution was investigated by using parameters, such as pH, temperature, adsorbent dose and contact time. A spectrophotometer technique was used for measuring the extent of adsorption. The extent of dye removal decreased with increasing adsorbent dosage and also increased with increasing contact time and temperature. The results revealed that the sorption capacity increases from 12.34 to 19.85 mg/g when the temperature increased from 25 to 55 ﻩC. This suggests that the sorption of MO dye onto WB is endothermic and activated process indicating that the higher temperature is more favorable for the dye sorption. Optimum pH value for dye adsorption was determined to be 4.0. strong pH-dependence of MO adsorption onto WB together with FTIR results indicate to possible involvement of physical forces such as hydrogen bonding, Vander Waals and covalent chemical bonds in the adsorption process. In addition, the adsorption data of MO by WB were applied to Lagergren,s pseudo first-order, pseudo second-order and the rate constants of first-order adsorption (k1 = 1.34x102 min-1 the rate constants of second-order adsorption (k2 = 2.93x10-3 g/mgmin were calculated, respectively.. The results indicate that WB could be employed as a low-cost alternative to other adsorbents in the removal of MO from aqueous solution.

  3. pH induced contrast in viscoelasticity imaging of biopolymers

    Science.gov (United States)

    Yapp, R D; Insana, M F

    2009-01-01

    Understanding contrast mechanisms and identifying discriminating features is at the heart of diagnostic imaging development. This report focuses on how pH influences the viscoelastic properties of biopolymers to better understand the effects of extracellular pH on breast tumour elasticity imaging. Extracellular pH is known to decrease as much as 1 pH unit in breast tumours, thus creating a dangerous environment that increases cellular mutatation rates and therapeutic resistance. We used a gelatin hydrogel phantom to isolate the effects of pH on a polymer network with similarities to the extracellular matrix in breast stroma. Using compressive unconfined creep and stress relaxation measurements, we systematically measured the viscoelastic features sensitive to pH by way of time domain models and complex modulus analysis. These results are used to determine the sensitivity of quasi-static ultrasonic elasticity imaging to pH. We found a strong elastic response of the polymer network to pH, such that the matrix stiffness decreases as pH was reduced, however the viscous response of the medium to pH was negligible. While physiological features of breast stroma such as proteoglycans and vascular networks are not included in our hydrogel model, observations in this study provide insight into viscoelastic features specific to pH changes in the collagenous stromal network. These observations suggest that the large contrast common in breast tumours with desmoplasia may be reduced under acidic conditions, and that viscoelastic features are unlikely to improve discriminability. PMID:19174599

  4. Application of microfluidic chip to realize controllable pH gradient

    Institute of Scientific and Technical Information of China (English)

    LUO Chunxiong; SUN Manhui; XU Luping; ZHANG Zhiling; C. Crozatier; CHEN Yong; JI Hang

    2005-01-01

    A kind of PH gradient microfluidic chips through soft-lithography microfabrication for isoelectric focusing (IEF) and high performance liquid chromatography (HPLC) is introduced here. These pH gradient chips have the advantages such as easy fabrication, controllable pH range and precision, isoelectric focusing and separation at the same time, low voltage for isoelectric focusing, and time stable pH gradient. This method has potential application to sample preparation, separation and analysis of microfluidic chips.

  5. Biohydrogen generation from jackfruit peel using anaerobic contact filter

    Energy Technology Data Exchange (ETDEWEB)

    Vijayaraghavan, Krishnan; Ahmad, Desa; Khairil Bin Ibrahim, Mohd [Department of Biological and Agricultural Engineering, Faculty of Engineering, UPM, 43400 Serdang, Selangor (Malaysia)

    2006-04-15

    A novel method of anaerobic digestion using contact filter was adopted for treating solid waste generated from the fruit processing industry, namely jackfruit, with the intention of generating energy free from greenhouse gases. A new source of microflora was isolated from cow dung by subjecting it to pH adjustment at 5+/-0.2 coupled with heat treatment at 105 deg C for 1h, and not less than three consecutive periods of heat treatment. The isolated microflora exhibited their capability to generate hydrogen while treating solid waste consisting of jackfruit peel. The biogas generation was found to be 0.72l/g VS (jackfruit peel) destroyed. The hydrogen content in the biogas was found to be consistent resulting in 55+/-2%, while the biogas was free from methane content. The effect of hydraulic retention time (HRT) on volatile solids destruction efficiency was investigated for an influent volatile solids content of 33g/l at an HRT of 7 and 12d. The results showed a volatile solids destruction efficiency of 22% and 50%, respectively, for the above said conditions. The efficiency of anaerobic digestion was also investigated for varying influent volatile solids content viz: 22.5, 17.1 and 11.3g/d at 12d HRT. The anaerobically digested jackfruit peel waste having an initial volatile solid content of 22.5g/d was subjected to filtration test at 15psi for a period of 1.3h. The sludge resulting from the filtration test had a solids content of 12%, whereas the filtrate had the following characteristics viz: pH 5.3+/-0.2, COD 1700mg/l, BOD 1175mg/l and TKN 120mg/l. (author)

  6. Electric Field and Humidity Trigger Contact Electrification

    Directory of Open Access Journals (Sweden)

    Yanzhen Zhang

    2015-01-01

    Full Text Available Here, we study the old problem of why identical insulators can charge one another on contact. We perform several experiments showing that, if driven by a preexisting electric field, charge is transferred between contacting insulators. This transfer happens because the insulator surfaces adsorb small amounts of water from a humid atmosphere. We believe the electric field then separates positively from negatively charged ions prevailing within the water, which we believe to be hydronium and hydroxide ions, such that at the point of contact, positive ions of one insulator neutralize negative ions of the other one, charging both of them. This mechanism can explain for the first time the observation made four decades ago that wind-blown sand discharges in sparks if and only if a thunderstorm is nearby.

  7. Improvement in nanoscale contact resistance of alumina

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Manjima; Chakraborty, Riya; Mandal, Ashok Kumar [CSIR - Central Glass and Ceramic Research Institute, Kolkata (India); Dey, Arjun [CSIR - Central Glass and Ceramic Research Institute, Kolkata (India); ISRO Satellite Centre, Thermal Systems Group, Bangalore (India); Mukhopadhyay, Anoop Kumar [CSIR - Central Glass and Ceramic Research Institute, Kolkata (India); Central Glass and Ceramic Research Institute, Kolkata 32 (India)

    2012-06-15

    In all contact-related applications such as the wear-resistant inserts, biomedical implants, high strain rate impact-resistant plates, etc., nanohardness, i.e. the intrinsic contact resistance at the nano scale, plays a major role. In spite of the wealth of literature, the studies on nanohardness of dense, coarse-grain alumina ceramics which represent many commercial varieties; have reasonably good hardness at the macro scale and characteristically exhibit R-curve behaviour, are far from significant. Here, to the best of our knowledge, we report for the first time the experimental observations of the increase in intrinsic contact resistance at the nano scale with the loading rate applied to a high-density ({proportional_to}95 % of theoretical) coarse-grain ({proportional_to}20 {mu}m) alumina ceramics. These observations were explained in terms of the initiation of nanoscale plasticity and maximum shear stress generated just underneath the nanoindenter. (orig.)

  8. Rhythm and Randomness in Human Contact

    CERN Document Server

    Freeman, Mervyn P; Yoneki, Eiko; Crowcroft, Jon

    2010-01-01

    There is substantial interest in the effect of human mobility patterns on opportunistic communications. Inspired by recent work revisiting some of the early evidence for a L\\'evy flight foraging strategy in animals, we analyse datasets on human contact from real world traces. By analysing the distribution of inter-contact times on different time scales and using different graphical forms, we find not only the highly skewed distributions of waiting times highlighted in previous studies but also clear circadian rhythm. The relative visibility of these two components depends strongly on which graphical form is adopted and the range of time scales. We use a simple model to reconstruct the observed behaviour and discuss the implications of this for forwarding efficiency.

  9. Contact sport and osteoarthritis.

    LENUS (Irish Health Repository)

    Molloy, Michael G

    2011-04-01

    Osteoarthritis (OA) is the most common joint disease in the world and the single largest cause of disability for those over 18 years. It affects more than twice as many people as does cardiac disease, and increases in incidence and prevalence with age. Animal and human studies have shown no evidence of increased risk of hip or knee OA with moderate exercise and in the absence of traumatic injury, sporting activity has a protective effect. One age-matched case control study found recreational runners who ran 12-14 miles per week for up to 40 years had no increase in radiological or symptomatic hip or knee OA. However, higher rates of hip OA occur in contact sports than in age-matched controls, with the highest rate in professional players. Soccer players with torn anterior cruciate ligaments (ACL) are more likely to develop knee OA than those with intact ACL. Early ACL repair reduces the risk of knee OA, but does not prevent it. Established injury prevention programmes have been refined to prevent injuries such as ACL rupture.

  10. Contact engineering for nano-scale CMOS

    KAUST Repository

    Hussain, Muhammad Mustafa

    2012-09-10

    High performance computation with longer battery lifetime is an essential component in our today\\'s digital electronics oriented life. To achieve these goals, field effect transistors based complementary metal oxide semiconductor play the key role. One of the critical requirements of transistor structure and fabrication is efficient contact engineering. To catch up with high performance information processing, transistors are going through continuous scaling process. However, it also imposes new challenges to integrate good contact materials in a small area. This can be counterproductive as smaller area results in higher contact resistance thus reduced performance for the transistor itself. At the same time, discovery of new one or two-dimensional materials like nanowire, nanotube, or atomic crystal structure materials, introduces new set of challenges and opportunities. In this paper, we are reviewing them in a synchronized fashion: fundamentals of contact engineering, evolution into non-planar field effect transistors, opportunities and challenges with one and two-dimensional materials and a new opportunity of contact engineering from device architecture perspective. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Ion-selective electrodes with solid contact for heavy metals determination

    Directory of Open Access Journals (Sweden)

    Wardak C.

    2013-04-01

    Full Text Available Potentiometric properties of ion-selective electrodes with solid contact for lead, cadmium and zinc determination were investigated. The ionic liquids (ILs alkyl methyl imidazolium chlorides are used as lipophilic ionic additive to the membrane phase and as transducer media. The basic analytical parameters of the studied electrodes, such as the slope characteristic, the detection limit, response time, lifetime, selectivity coefficients against various inorganic cations as well as the dependence of the electrodes potential on pH were determined. The obtained electrode are characterized by good analytical parameters: theoretical characteristic slope, low detection limit, short response time and very long lifetime. The electrodes was successfully applied to the direct determination of lead, cadmium and zinc ions in waste water samples. The results obtained indicate that the electrodes provide a good alternative for the determination of these heavy metals in real samples.

  12. Noise of sliding rough contact

    Science.gov (United States)

    Le Bot, Alain

    2017-01-01

    This article is a discussion about the origin of friction noise produced when rubbing solids having rough surfaces. We show that noise emerges from numerous impacts into the contact between antagonist asperities of surfaces. Prediction of sound sources reduces to a statistical problem of contact mechanics. On the other hand, contact is also responsible of dissipation of vibration. This leads to the paradoxical result that the noise may not be proportional to the number of sources.

  13. Molecular Dynamics Simulations Capture the Misfolding of the Bovine Prion Protein at Acidic pH

    Directory of Open Access Journals (Sweden)

    Chin Jung Cheng

    2014-02-01

    Full Text Available Bovine spongiform encephalopathy (BSE, or mad cow disease, is a fatal neurodegenerative disease that is transmissible to humans and that is currently incurable. BSE is caused by the prion protein (PrP, which adopts two conformers; PrPC is the native innocuous form, which is α-helix rich; and PrPSc is the β-sheet rich misfolded form, which is infectious and forms neurotoxic species. Acidic pH induces the conversion of PrPC to PrPSc. We have performed molecular dynamics simulations of bovine PrP at various pH regimes. An acidic pH environment induced conformational changes that were not observed in neutral pH simulations. Putative misfolded structures, with nonnative β-strands formed in the flexible N-terminal domain, were found in acidic pH simulations. Two distinct pathways were observed for the formation of nonnative β-strands: at low pH, hydrophobic contacts with M129 nucleated the nonnative β-strand; at mid-pH, polar contacts involving Q168 and D178 facilitated the formation of a hairpin at the flexible N-terminus. These mid- and low pH simulations capture the process of nonnative β-strand formation, thereby improving our understanding of how PrPC misfolds into the β-sheet rich PrPSc and how pH factors into the process.

  14. Elastohydrodynamics of contact in adherent sheets

    OpenAIRE

    Carlson, Andreas; Mandre, Shreyas; Mahadevan, L

    2015-01-01

    Adhesive contact between a thin elastic sheet and a substrate in a liquid environment arises in a range of biological, physical and technological applications. By considering the dynamics of this process that naturally couples fluid flow, long wavelength elastic deformations and microscopic adhesion, and solving the resulting partial differential equation numerically, we uncover the short-time dynamics of the onset of adhesion and the long-time dynamics of a steady propagating adhesion front....

  15. A novel methodology based on contact angle hysteresis approach for surface changes monitoring in model PMMA-Corega Tabs system

    Science.gov (United States)

    Pogorzelski, Stanisław J.; Berezowski, Zdzisław; Rochowski, Paweł; Szurkowski, Janusz

    2012-02-01

    The aim of the paper is to propose a quantitative description of dental surface modifications, resulting from application of Corega and oral cavity liquids, with several surface parameters derived from liquid/solid contact angle measurements. In particular, to predict the long-term effectiveness of denture cleansers in prosthetics, it is necessary to determine surface wettability variations for model dental materials/probe liquid systems related to the contamination effect caused by substances found in the oral cavity. A novel simple low-cost methodology, based on liquid drop contact angle hysteresis CAH approach developed by Chibowski, was adopted to trace solid surface free energy changes in the model PMMA-Corega Tabs interfacial layer. Contact angle and its hysteresis were studied with a sessile drop-inclined plate method in contact with a cleanser (Corega Tabs) and model liquids found in the oral cavity. The apparent solid surface free energy, adsorptive film pressure, work of adhesion and spreading were derived from contact angle hysteresis data for both model solid surfaces (reference) and samples affected by different reactive liquids for a certain time. A time-dependent surface wettability changes of dentures were expressed quantitatively in terms of the corresponding variations of the surface energy parameters which turned out to be unequivocally related to the cleanser exposure time and polarity of the liquids applied to the dental material. The novel methodology appeared to be a useful tool for long term surface characterization of dental materials treated with surfactants-containing liquids capable of forming adhesive layers. The time of optimal use and effectiveness of cleansers are also reflected dynamically in the corresponding variations of the surface wettability parameters. Further studies on a large group of dental surface-probe liquid systems are required to specify the role played by other important factors (liquid polarity, pH and temperature).

  16. Ion Implanted Passivated Contacts for Interdigitated Back Contacted Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Young, David L.; Nemeth, William; LaSalvia, Vincenzo; Reedy, Robert; Bateman, Nicholas; Stradins, Pauls

    2015-06-14

    We describe work towards an interdigitated back contacted (IBC) solar cell utilizing ion implanted, passivated contacts. Formation of electron and hole passivated contacts to n-type CZ wafers using tunneling SiO2 and ion implanted amorphous silicon (a-Si) are described. P and B were ion implanted into intrinsic amorphous Si films at several doses and energies. A series of post-implant anneals showed that the passivation quality improved with increasing annealing temperatures up to 900 degrees C. The recombination parameter, Jo, as measured by a Sinton lifetime tester, was Jo ~ 14 fA/cm2 for Si:P, and Jo ~ 56 fA/cm2 for Si:B contacts. The contact resistivity for the passivated contacts, as measured by TLM patterns, was 14 milliohm-cm2 for the n-type contact and 0.6 milliohm-cm2 for the p-type contact. These Jo and pcontact values are encouraging for forming IBC cells using ion implantation to spatially define dopants.

  17. Contextualizing Intergroup Contact: Do Political Party Cues Enhance Contact Effects?

    DEFF Research Database (Denmark)

    Sønderskov, Kim Mannemar; Thomsen, Jens Peter Frølund

    2015-01-01

    This article examines intergroup contact effects in different political contexts. We expand on previous efforts of social psychologists by incorporating the messages of political parties as a contextual trigger of group membership awareness in contact situations. We argue that the focus among...

  18. Study of the advancing and receding contact angles: liquid sorption as a cause of contact angle hysteresis.

    Science.gov (United States)

    Lam, C N C; Wu, R; Li, D; Hair, M L; Neumann, A W

    2002-02-25

    Two types of experiments were used to study the behavior of both advancing and receding contact angles, namely the dynamic one-cycle contact angle (DOCA) and the dynamic cycling contact angle (DCCA) experiments. For the preliminary study, DOCA measurements of different liquids on different solids were performed using an automated axisymmetric drop shape analysis-profile (ADSA-P). From these experimental results, four patterns of receding contact angle were observed: (1) time-dependent receding contact angle; (2) constant receding contact angle; (3) 'stick/slip'; (4) no receding contact angle. For the purpose of illustration, results from four different solid surfaces are shown. These solids are: FC-732-coated surface; poly(methyl methacrylate/n-butyl methacrylate) [P(MMA/nBMA)]; poly(lactic acid) (DL-PLA); and poly(lactic/glycolic acid) 50/50 (DL-PLGA 50/50). Since most of the surfaces in our studies exhibit time dependence in the receding contact angle, a more extended study was conducted using only FC-732-coated surfaces to better understand the possible causes of decreasing receding contact angle and contact angle hysteresis. Contact angle measurements of 21 liquids from two homologous series (i.e. n-alkanes and 1-alcohols) and octamethylcyclotetrasiloxane (OCMTS) on FC-732-coated surfaces were performed. It is apparent that the contact angle hysteresis decreases with the chain length of the liquid. It was found that the receding contact angle equals the advancing angle when the alkane molecules are infinitely large. These results strongly suggest that the chain length and size of the liquid molecule could contribute to contact angle hysteresis phenomena. Furthermore, DCCA measurements of six liquids from the two homologous series on FC-732-coated surfaces were performed. With these experimental results, one can construe that the time dependence of contact angle hysteresis on relatively smooth and homogeneous surfaces is mainly caused by liquid retention

  19. Industrial PhD report: Sustainable Innovation

    DEFF Research Database (Denmark)

    Olesen, Gitte Gylling Hammershøj

    2011-01-01

    Erhvervs PhD rapport udarbejdet i tilknytning til Erhvervs PhD kurset der er obligatorisk for Erhvervs PhD studerende. Rapporten omhandler relationer melllem den akademiske verden og industrien i sammenhæng med PhD projektet, betragtet og analyseret gennem teori om bæredygtig innovation....

  20. Industrial PhD report: Sustainable Innovation

    DEFF Research Database (Denmark)

    Olesen, Gitte Gylling Hammershøj

    2011-01-01

    Erhvervs PhD rapport udarbejdet i tilknytning til Erhvervs PhD kurset der er obligatorisk for Erhvervs PhD studerende. Rapporten omhandler relationer melllem den akademiske verden og industrien i sammenhæng med PhD projektet, betragtet og analyseret gennem teori om bæredygtig innovation....