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Sample records for factors water contact

  1. Factor XII Contact Activation.

    PubMed

    Naudin, Clément; Burillo, Elena; Blankenberg, Stefan; Butler, Lynn; Renné, Thomas

    2017-03-27

    Contact activation is the surface-induced conversion of factor XII (FXII) zymogen to the serine protease FXIIa. Blood-circulating FXII binds to negatively charged surfaces and this contact to surfaces triggers a conformational change in the zymogen inducing autoactivation. Several surfaces that have the capacity for initiating FXII contact activation have been identified, including misfolded protein aggregates, collagen, nucleic acids, and platelet and microbial polyphosphate. Activated FXII initiates the proinflammatory kallikrein-kinin system and the intrinsic coagulation pathway, leading to formation of bradykinin and thrombin, respectively. FXII contact activation is well characterized in vitro and provides the mechanistic basis for the diagnostic clotting assay, activated partial thromboplastin time. However, only in the past decade has the critical role of FXII contact activation in pathological thrombosis been appreciated. While defective FXII contact activation provides thromboprotection, excess activation underlies the swelling disorder hereditary angioedema type III. This review provides an overview of the molecular basis of FXII contact activation and FXII contact activation-associated disease states.

  2. Contact Freezing of Water by Salts.

    PubMed

    Niehaus, Joseph; Cantrell, Will

    2015-09-03

    Water is unlikely to crystallize homogeneously at temperatures greater than -34 °C. Freezing at higher temperatures is heterogeneous-catalyzed by the presence of a second substance. If that substance is at an air-water interface, then the mode is called contact freezing, and it typically will trigger nucleation at a higher temperature than if the substance were wholly immersed within the liquid. We find that the impact of salt particles initiates freezing in experiments using water droplets at supercoolings of 9 to 16 °C. These results show that contact freezing nuclei need not be effective as immersion mode nuclei. We discuss our results in the context of proposed mechanisms of contact freezing. Finally, we use the time scales for diffusion of heat and of ions and the propagation of a sound wave through the droplet to estimate that contact freezing occurs within 10 ns of impact.

  3. Picoliter water contact angle measurement on polymers.

    PubMed

    Taylor, Michael; Urquhart, Andrew J; Zelzer, Mischa; Davies, Martyn C; Alexander, Morgan R

    2007-06-19

    Water contact angle measurement is the most common method for determining a material's wettability, and the sessile drop approach is the most frequently used. However, the method is generally limited to macroscopic measurements because the base diameter of the droplet is usually greater than 1 mm. Here we report for the first time on a dosing system to dispense smaller individual droplets with control of the position and investigate whether water contact angles determined from picoliter volume water droplets are comparable with those obtained from the conventional microliter volume water droplets. This investigation was conducted on a group of commonly used polymers. To demonstrate the higher spatial resolution of wettability that can be achieved using picoliter volume water droplets, the wettability of a radial plasma polymer gradient was mapped using a 250 microm interval grid.

  4. Pion form factor from a contact interaction

    SciTech Connect

    Gutierrez-Guerrero, L. X.; Bashir, A.; Cloeet, I. C.; Roberts, C. D.

    2010-06-15

    In a Poincare-covariant vector-boson-exchange theory, the pion possesses components of pseudovector origin, which materially influence its observable properties. For a range of such quantities, we explore the consequences of a momentum-independent interaction, regularized in a symmetry-preserving manner. The contact interaction, while capable of describing pion static properties, produces a form factor whose evolution for Q{sup 2}>0.17 GeV{sup 2} disagrees markedly with experiment and whose asymptotic power-law behavior conflicts strongly with perturbative QCD.

  5. Factors influencing the prescribing of hydrogel contact lenses.

    PubMed

    Efron, Nathan; Morgan, Philip B

    2009-12-01

    Despite the current market popularity of silicone hydrogel contact lenses, conventional hydrogel lenses still represent a significant proportion of the overall contact lens market. Data gathered from annual UK contact lens fitting surveys over the past 13 years indicate that 64% of hydrogel lenses prescribed during this period were of low/medium water content (< or =60% water). Whereas, in the past, practitioners would choose the water content of a hydrogel lens to meet specific clinical needs, this choice appears today to be largely governed by product availability.

  6. Health Risks of Limited-Contact Water Recreation

    PubMed Central

    Pratap, Preethi; Wroblewski, Meredith; Hryhorczuk, Daniel O.; Li, Hong; Liu, Li C.; Scheff, Peter A.

    2011-01-01

    Background: Wastewater-impacted waters that do not support swimming are often used for boating, canoeing, fishing, kayaking, and rowing. Little is known about the health risks of these limited-contact water recreation activities. Objectives: We evaluated the incidence of illness, severity of illness, associations between water exposure and illness, and risk of illness attributable to limited-contact water recreation on waters dominated by wastewater effluent and on waters approved for general use recreation (such as swimming). Methods: The Chicago Health, Environmental Exposure, and Recreation Study was a prospective cohort study that evaluated five health outcomes among three groups of people: those who engaged in limited-contact water recreation on effluent-dominated waters, those who engaged in limited-contact recreation on general-use waters, and those who engaged in non–water recreation. Data analysis included survival analysis, logistic regression, and estimates of risk for counterfactual exposure scenarios using G-computation. Results: Telephone follow-up data were available for 11,297 participants. With non–water recreation as the reference group, we found that limited-contact water recreation was associated with the development of acute gastrointestinal illness in the first 3 days after water recreation at both effluent-dominated waters [adjusted odds ratio (AOR) 1.46; 95% confidence interval (CI): 1.08, 1.96] and general-use waters (1.50; 95% CI: 1.09, 2.07). For every 1,000 recreators, 13.7 (95% CI: 3.1, 24.9) and 15.1 (95% CI: 2.6, 25.7) cases of gastrointestinal illness were attributable to limited-contact recreation at effluent-dominated waters and general-use waters, respectively. Eye symptoms were associated with use of effluent-dominated waters only (AOR 1.50; 95% CI: 1.10, 2.06). Among water recreators, our results indicate that illness was associated with the amount of water exposure. Conclusions: Limited-contact recreation, both on effluent

  7. The Danger of Using Tap Water with Contact Lenses

    EPA Pesticide Factsheets

    Acanthamoeba is a microbe that is very common in tap water. It has two forms: the trophozoite and the cyst. These trophozoites and cysts can stick to the surface of your contact lenses and then infect your eye.

  8. Drinking Water Program Contacts | Drinking Water in New ...

    EPA Pesticide Factsheets

    2017-07-06

    Information on Drinking Water in New England. Major Topics covered include: Conservation, Private Wells, Preventing Contamination, Drinking Water Sources, Consumer Confidence Reports, and Drinking Water Awards.

  9. Dynamic contact angle of water-based titanium oxide nanofluid.

    PubMed

    Radiom, Milad; Yang, Chun; Chan, Weng Kong

    2013-06-11

    This paper presents an investigation into spreading dynamics and dynamic contact angle of TiO2-deionized water nanofluids. Two mechanisms of energy dissipation, (1) contact line friction and (2) wedge film viscosity, govern the dynamics of contact line motion. The primary stage of spreading has the contact line friction as the dominant dissipative mechanism. At the secondary stage of spreading, the wedge film viscosity is the dominant dissipative mechanism. A theoretical model based on combination of molecular kinetic theory and hydrodynamic theory which incorporates non-Newtonian viscosity of solutions is used. The model agreement with experimental data is reasonable. Complex interparticle interactions, local pinning of the contact line, and variations in solid-liquid interfacial tension are attributed to errors.

  10. Dynamic contact angle of water-based titanium oxide nanofluid

    PubMed Central

    2013-01-01

    This paper presents an investigation into spreading dynamics and dynamic contact angle of TiO2-deionized water nanofluids. Two mechanisms of energy dissipation, (1) contact line friction and (2) wedge film viscosity, govern the dynamics of contact line motion. The primary stage of spreading has the contact line friction as the dominant dissipative mechanism. At the secondary stage of spreading, the wedge film viscosity is the dominant dissipative mechanism. A theoretical model based on combination of molecular kinetic theory and hydrodynamic theory which incorporates non-Newtonian viscosity of solutions is used. The model agreement with experimental data is reasonable. Complex interparticle interactions, local pinning of the contact line, and variations in solid–liquid interfacial tension are attributed to errors. PMID:23759071

  11. Risk factors with contact lens related suppurative keratitis.

    PubMed

    Stapleton, F; Dart, J K; Minassian, D

    1993-10-01

    Risk factors in contact lens related suppurative keratitis were investigated. Over 12 months, sixty contact lens wearers presented with presumed microbial keratitis and 147 presented with presumed sterile keratitis. The control group consisted of contact lens wearers without lens related disorders (n = 507). The relative risk of microbial keratitis for extended wear soft contact lens users were 36.8 times (12.6-107.6) that of rigid gas permeable (RGP) contact lens users; while the relative risk of sterile keratitis among extended wear soft lens users was 4.6 times (2.2-9.9) that of RGP lens users. For daily wear soft contact lens users, the relative risk of microbial keratitis was 4.2 times (1.1-16.0) that of RGP lens wearers; for sterile keratitis the relative risk was 2.3 times (1.3-4.3) greater than RGP contact lens users. A multivariable logistic regression analysis was used to examine associated risk factors for daily and extended wear soft lens users. The type of disinfection system and its frequency of use were associated with both microbial keratitis and sterile keratitis in daily wear users. Duration of overnight wear and gender were associated with microbial keratitis, while a patient's age and socioeconomic class were associated with sterile keratitis. Different relative risks and risk factors for microbial keratitis and sterile keratitis support the use of a clinical definition to differentiate the diseases.

  12. Factor XI and Contact Activation as Targets for Antithrombotic Therapy

    PubMed Central

    Gailani, David; Bane, Charles E.; Gruber, Andras

    2015-01-01

    Summary The most commonly used anticoagulants produce therapeutic antithrombotic effects either by inhibiting thrombin or factor Xa, or by lowering the plasma levels of the precursors of these key enzymes, prothrombin and factor X. These drugs do not distinguish between thrombin generation contributing to thrombosis from thrombin generation required for hemostasis. Thus, anticoagulants increase bleeding risk, and many patients who would benefit from therapy go untreated because of comorbidities that place them at unacceptable risk for hemorrhage. Studies in animals demonstrate that components of the plasma contact activation system contribute to experimentally-induced thrombosis, despite playing little or no role in hemostasis. Attention has focused on factor XII, the zymogen of a protease (factor XIIa) that initiates contact activation when blood is exposed to foreign surfaces; and factor XI, the zymogen of the protease factor XIa, which links contact activation to the thrombin generation mechanism. In the case of factor XI, epidemiologic data indicate this protein contributes to stroke and venous thromboembolism, and perhaps myocardial infarction, in humans. A phase 2 trial showing that reduction of factor XI may be more effective than low-molecular-weight heparin at preventing venous thrombosis during knee replacement surgery provides proof of concept for the premise that an antithrombotic effect can be uncoupled from an anticoagulant effect in humans by targeting components of contact activation. Here we review data on the role of factor XI and factor XII in thrombosis, and results of pre-clinical and human trials for therapies targeting these proteins. PMID:25976012

  13. Tastes associated with products in contact with drinking water.

    PubMed

    Marchesan, M; Morran, J

    2004-01-01

    Over the past 9 years the Australian Water Quality Centre (AWQC) has conducted testing in accordance with Australian and New Zealand Standard AS/NZS 4020--"Products for use in contact with drinking water" (1999). A test included as part of this standard is taste of water extracts. This test assesses the ability of products to impart discernible taste to drinking water using panellists trained in accordance with Standard Methods for the Examination of Water and Wastewater--Flavour Profile Analysis 2170 B (1999). Over 1000 products from companies worldwide, have been assessed at the AWQC in accordance with AS/NZS 4020 including pipes, valves, tap fittings and numerous other products used in contact with water. The products must not impart any discernible taste to obtain compliance and be deemed suitable for use in contact with drinking water. This study compiles the products assessed and the types of tastes obtained from both chlorinated and non-chlorinated extracts. In particular the study focuses on taste associated with polyethylene pipes, coatings and valves, which in some instances have been problematic. Analysis revealed that most taste problems occur when chlorinated water has been used in extraction experiments and this is in line with consumer complaints regarding taste imparted by plumbing products. The collation of this data provides a valuable assessment for manufacturers, the water industry and consumers.

  14. Acanthamoeba keratitis associated with tap water use during contact lens cleaning: manufacturer guidelines need to change.

    PubMed

    Legarreta, John E; Nau, Amy C; Dhaliwal, Deepinder K

    2013-03-01

    Contact lens-associated Acanthamoeba keratitis continues to be a significant cause of visual morbidity in the United States. Although exposure to water sources while wearing lenses has been a known risk factor for infection for decades, this behavior in several contact lens hygiene protocols continues to prevail. In this review, we surveyed the currently available contact lens cleaning solutions for both soft and rigid gas-permeable contact lenses and reviewed the cleaning instructions of the available solutions. Discrepancies between clinician recommendations and written instructions on a solution packages continues to persist, and we advocate a revision in current manufacturer guidelines to include explicit warnings against use of tap or distilled water sources for cleaning contact lenses or their storage cases.

  15. Dynamic contact angle and three-phase contact line of water drop on copper surface

    NASA Astrophysics Data System (ADS)

    Orlova, E. G.; Feoktistov, D. V.; Batishcheva, K. A.

    2015-10-01

    Nowadays there is a lack of experimental data describing the physical process of drop spreading on a solid metal surface for developing wetting and spreading theory. The experimental data obtained by using the high speed video-recording will allow to identify unknown previously spreading modes as well as the change of the dynamic contact angle and the three-phase contact line. The purpose of the work is to determine the effect of the drop growth rate and the copper substrate surface roughness on the dynamic contact angle and the three-phase contact line speed at distilled water drop spreading. Shadow and Schlieren methods are used to obtain experimental data. Three drop spreading modes on the rough surfaces were identified. Time dependences of the dynamic contact angle and contact line speed were obtained. Experimental results can be used for assessing the validity of the developed mathematical models of wetting and spreading processes in the field of micro- and nanoelectronics, ink jet printing, thin-film coatings, spray cooling, and optoelectronics.

  16. Water contact angles and hysteresis of polyamide surfaces.

    PubMed

    Extrand, C W

    2002-04-01

    The wetting behavior of a series of aliphatic polyamides (PAs) has been examined. PAs with varying amide content and polyethylene (PE) were molded against glass to produce surfaces with similar roughness. After cleaning, chemical composition of the surfaces was verified with X-ray photoelectron spectroscopy. Advancing and receding contact angles were measured from small sessile water drops. Contact angles decreased with amide content while hysteresis increased. Hysteresis arose primarily from molecular interactions between the contact liquid and the solid substrates, rather than moisture absorption, variations in crystallinity, surface deformation, roughness, reorientation of amide groups, or surface contamination. Free energies of hysteresis were calculated from contact angles. For PE, which is composed entirely of nonpolar methylene groups, free energies were equivalent to the strength of dispersive van der Waals bonds. For PAs, free energies corresponded to fractional contributions from the dispersive methylene groups and polar amide groups.

  17. What is the contact angle of water on graphene?

    PubMed

    Taherian, Fereshte; Marcon, Valentina; van der Vegt, Nico F A; Leroy, Frédéric

    2013-02-05

    Although experimental and theoretical studies have addressed the question of the wetting properties of graphene, the actual value of the contact angle of water on an isolated graphene monolayer remains unknown. While recent experimental literature indicates that the contact angle of water on graphite is in the range 90-95°, it has been suggested that the contact angle on graphene may either be as high as 127° or moderately enhanced in comparison with graphite. With the support of classical molecular dynamics simulations using empirical force-fields, we develop an argumentation to show that the value of 127° is an unrealistic estimate and that a value of the order of 95-100° should be expected. Our study establishes a connection between the variation of the work of adhesion of water on graphene-based surfaces and the interaction potential between individual water molecules and these surfaces. We show that a variation of the contact angle from 90° on graphite to 127° on graphene would imply that both of the first two carbon layers of graphite contribute approximately the same interaction energy with water. Such a situation is incompatible with the short-range nature of the interaction between water and this substrate. We also show that the interaction potential energy between water and the graphene-based substrates is the main contribution to the work of adhesion of water with a relative magnitude that is independent of the number of graphene layers. We introduce the idea that the remaining contribution is entropic in nature and is connected to the fluctuations in the water-substrate interaction energy.

  18. Contact angles of wetting and water stability of soil structure

    NASA Astrophysics Data System (ADS)

    Kholodov, V. A.; Yaroslavtseva, N. V.; Yashin, M. A.; Frid, A. S.; Lazarev, V. I.; Tyugai, Z. N.; Milanovskiy, E. Yu.

    2015-06-01

    From the soddy-podzolic soils and typical chernozems of different texture and land use, dry 3-1 mm aggregates were isolated and sieved in water. As a result, water-stable aggregates and water-unstable particles composing dry 3-1 mm aggregates were obtained. These preparations were ground, and contact angles of wetting were determined by the static sessile drop method. The angles varied from 11° to 85°. In most cases, the values of the angles for the water-stable aggregates significantly exceeded those for the water-unstable components. In terms of carbon content in structural units, there was no correlation between these parameters. When analyzing the soil varieties separately, the significant positive correlation between the carbon content and contact angle of aggregates was revealed only for the loamy-clayey typical chernozem. Based on the multivariate analysis of variance, the value of contact wetting angle was shown to be determined by the structural units belonging to water-stable or water-unstable components of macroaggregates and by the land use type. In addition, along with these parameters, the texture has an indirect effect.

  19. Investigation of factors affecting electrical contacts on single germanium nanowires

    NASA Astrophysics Data System (ADS)

    Sett, Shaili; Das, K.; Raychaudhuri, A. K.

    2017-03-01

    We report an experimental investigation of the quality of electrical contacts made on single Germanium nanowires (grown using Au catalyst from vapor) using Cr/Au contact pads. The nanowires are single crystalline and have a thin layer of oxide on them. We find that a low specific contact resistivity of 10-6 Ω cm2 can be obtained in nanowires with low resistance and the contact resistance enhances almost linearly with the nanowire resistivity. The metal semiconductor junction shows an ideality factor close to unity. A low barrier height of 0.15 eV can be obtained in nanowires of lower resistivities which increase to nearly 0.3 eV for nanowires of higher resistivity. The experiments were carried down to 10 K, and junction characteristics as a function of temperature were evaluated. The specific contact resistance increases on cooling but the barrier shows suppression as the nanowire is cooled, along with an enhancement of the ideality factor. We analyze the temperature dependence of these parameters using a model that assumes a Gaussian distribution of barrier heights in the contact region. The temperature dependence predicted by the model was observed, and the relevant parameters were obtained from the data.

  20. Effect of contact angle and contact angle hysteresis on the floatability of spheres at the air-water interface.

    PubMed

    Feng, Dong-Xia; Nguyen, Anh V

    2017-10-01

    The floatability of solid particles on the water surface governs many natural phenomena and industrial processes including film flotation and froth flotation separation of coal and valuable minerals. For many years, the contact angle (CA) has been postulated as the key factor in determining the particle floatability. Indeed, the maximum force (tenacity) supporting the flotation of fine spheres was conjectured to occur when the apical angle of the contact circle is equal to the contact angle. In this paper, the model predictions are reviewed and compared with experimental results. It is shown that CA can be affected by many physical and chemical factors such as surface roughness and chemical heterogeneity and can have a range of values known as the CA hysteresis. This multiple-valued CA invalidates the available theories on the floatability of spheres. Even the intuitive replacement of CA by the advancing (maximum) CA in the classical theories can be wrong. A few new examples are also reviewed and analyzed to demonstrate the significance of CA variation in controlling the particle floatability. They include the pinning of the contact line at the sharp edge, known as the Gibbs inequality condition, and the nearby interaction among floating particles, known as lateral inter-particle interaction. It is concluded that our quantitative understanding of the floatability of real particles being irregular and heterogeneous both morphologically and chemically is still far from being satisfactory. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Tear Film, Contact Lens, and Patient Factors Associated with Corneal Staining

    PubMed Central

    Sinnott, Loraine T.

    2011-01-01

    Purpose. The purpose of this study was to examine ocular surface and tear film, contact lens, care solution, medical, and patient-related factors that are associated with corneal staining in contact lens wearers. Methods. In this cross-sectional/nested case–control study, in addition to the assessment of corneal staining with fluorescein, a variety of tear film and ocular surface, contact lens, and patient-related factors were examined. Poisson regression models were used to examine the relation between corneal staining and these factors. Results. Data from 413 patients were eligible for the analyses described. The average age was 30.6 ± 11.1 years, and 277 (67.1%) of the patients were women. Several factors were shown to be related to increased corneal staining in multivariate modeling, including increased daily wearing times (P = 0.0006), lower income (P = 0.0008), lissamine green conjunctival staining (P = 0.002), contact lens deposition (P = 0.007), increased tear meniscus height (P = 0.007), and decreased hydrogel nominal water content (P = 0.02). The wearing of silicone hydrogels (as opposed to hydrogels) was protective against corneal staining (P = 0.0004). Notably, neither contact lens care solutions nor disinfectants were associated with corneal staining. Conclusions. Corneal staining in contact lens wearers continues to be a frequent, but not well understood, outcome. These data suggest that contact lens factors (water content, material, wearing time, and deposition) are more generally associated with corneal staining than are contact lens care solutions or other ocular surface and tear film, demographic, or medical factors. PMID:21087960

  2. The change in contact angle at unsaturated CO2-water conditions: Implication on geological carbon dioxide sequestration

    NASA Astrophysics Data System (ADS)

    Jafari, Mohammad; Jung, Jongwon

    2016-10-01

    The performance of a geologic carbon storage site strongly depends on the capillary pressure of sealing rock and formations. While wettability of minerals is a key factor in capillary pressure, published contact angles are inconsistent. This study explores the discrepancy of published contact angles in order to reduce the uncertainty of measured laboratory contact angles, and understand the variation of contact angles at unsaturated CO2-water conditions. A ratio of droplet dimension and triple line (or contact line) are used to explain the observed wide range of contact angles and the variation of contact angle at unsaturated conditions. Results show that the shape factor has a good agreement with contact angle change during CO2 dissolution in water. Silica substrate has clear two pinned and slip stages of triple line during CO2 droplet dissolution, which cause contact angle on silica substrate to increase from 34.5° to 42.1°. However, mica substrate has the repeated pinned and slip stages due to the heterogeneity of mica surface, which cause contact angle to increase dramatically from 25.4° to 68.1°. Thus, both the impact of the unsaturated CO2-water conditions on the wide range of contact angle and the heterogeneity of mineral surface should be considered when one estimates capillary pressure based on contact angle in geological CO2 sequestration.

  3. Pyrite in contact with supercritical water: the desolation of steam.

    PubMed

    Stirling, András; Rozgonyi, Tamás; Krack, Matthias; Bernasconi, Marco

    2015-07-14

    The supercritical water-pyrite interface has been studied by ab initio molecular dynamics simulation. Extreme conditions are relevant in the iron-sulfur world (ISW) theory where prebiotic chemical reactions are postulated to occur at the mineral-water interface. We have investigated the properties of this interface under such conditions. We have come to the conclusion that hot-pressurized water on pyrite leads to an interface where a dry pyrite surface is in contact with the nearby SC water without significant chemical interactions. This picture is markedly different from that under ambient conditions where the surface is fully covered with adsorbed water molecules which is of relevance for the surface reactions of the ISW hypothesis.

  4. The contribution of water contact behavior to the high Schistosoma mansoni Infection rates observed in the Senegal River Basin.

    PubMed

    Sow, Seydou; de Vlas, Sake J; Stelma, Foekje; Vereecken, Kim; Gryseels, Bruno; Polman, Katja

    2011-07-18

    Northern Senegal. Comparison with fecal egg counts in the respective age and sex groups further revealed that water contact levels did not unambiguously correspond with infection levels, indicating that factors other than exposure also play a role in determining intensity of infection.

  5. Exposure to Schistosoma mansoni infection in a rural area of Brazil. I: water contact.

    PubMed

    Gazzinelli, A; Bethony, J; Fraga, L A; LoVerde, P T; Correa-Oliveira, R; Kloos, H

    2001-02-01

    The study of water contact patterns in rural Brazil presents unique challenges due to widely dispersed settlement patterns, the ubiquity of water contact sites, and the privatization of water resources. This study addresses these challenges by comparing the two most widely used methods of assessing water contact behaviour: direct observation and survey. The results of a 7-day direct observation of water contact were compared with water contact surveys administered 1 week after and then 1 year after the direct observation study. The direct observation study recorded a water contact rate higher than reported by other investigators (3.2 contacts per person per day); however, 75% of these contacts were for females and consisted mainly of domestic activities occurring around the household. A comparison of the frequency of water contact activities between the direct observation and the two surveys revealed several important points. First, no significant differences were found between methods for routine water contact activities (e.g. bathing), indicating that participants were able to accurately self-report some types of water contact activities. Second, significant differences were found in the recording of water contact activities that took place outside the observation area, indicating that direct observation may under-report water contact activities in areas where contact sites are dispersed widely. Third, significant differences between the direct observation and the survey method were more common for males than for females, indicating that the combination of widespread water contact sites and gender-specific division of labour may result in under-reporting of male contacts by direct observation methods. In short, despite the limitations in the recording of duration and body exposure, the survey method may more accurately record the frequency of water contact activities than direct observation methods in areas of widely dispersed water contact sites. Hence, surveys

  6. Risk factors and common contact allergens in facial allergic contact dermatitis patients.

    PubMed

    Kasemsarn, Pranee; Iamphonrat, Thanawan; Boonchai, Waranya

    2016-04-01

    Facial dermatitis is commonly encountered in dermatologic practice. It is sometimes difficult to manage because its causative factors may be multiple and difficult to diagnose. This study was designed to identify the characteristics, patch test results, and final diagnoses of facial dermatitis patients who were referred to a contact dermatitis clinic and to identify factors associated with facial allergic contact dermatitis (ACD). We retrospectively reviewed case records of facial dermatitis patients who underwent patch testing at the clinic during the period from July 2006 to June 2011. Of the 891 patients patch-tested, 244 (27.4%) had facial dermatitis. Female patients were 9.1 times more predominant than male patients. The mean ± standard deviation age of patients was 37.3 ± 14.8 years. A total of 199 (81.6%) patients demonstrated at least one positive reaction to a patch test, 66.7% of which were clinically relevant. Allergic contact dermatitis was diagnosed in 45.5% of patients. Independent factors predisposing towards facial dermatitis were female sex, having a previous history of cosmetic allergy, a positive patch test reaction to hairdressing product-related allergens, and a positive allergic reaction to preservative allergens. The prevalence of facial dermatitis was 27.4%. Almost half of all patients with facial dermatitis demonstrated ACD. Factors associated with facial ACD were female gender, a history of cosmetic allergy, and positive patch test reactions to hairdressing product-related allergens and preservatives. © 2015 The International Society of Dermatology.

  7. Contact-angle of water drop on a sloped water repellent soil

    NASA Astrophysics Data System (ADS)

    Arye, Gilboa; Bachmann, Jörg

    2015-04-01

    Soil water repellency is a well-known phenomenon worldwide and currently well documented in the scientific literature. Most methods used to characterize the magnitude and/or persistency of soil water repellency is directly or indirectly related to the initial advancing contact angle at the solid-liquid-vapor interface. These methods are commonly involved by placing a water (or solution) drops on horizontal surface of water repellent soil (WRS)particles attached to a plane surface. Under natural conditions, however, a soil surface layer is mostly sloped due to micro and/or macro topography. Therefore, the formation of advancing contact angle (downhill) and receding contact angle (uphill) should be considered, rather than a unique value of the contact angle. The difference between the advancing and receding contact angle values is defined as the contact angle hysteresis, commonly attributed to surface roughness and/or chemical heterogeneities. For a given tilt angle, a water drop exceeding a critical volume will slide downhill. Alternatively, for a given drop volume, a critical sliding angle can be defined. Measurements of advancing, receding and sliding angles on sloped WRS is indispensable for our understanding on water adhesion due to hysteresis and may provide critical values for predicting the initiation of water runoff in sloped landscapes on the micro and macro scales of WRS. Accordingly, the main objective of this study was to measure the advancing and receding contact angles on a sloped WRS as a function of: i) water drop volume, ii) particle size distribution and iii) surface slope. The measurements of contact angles on sloped WRS were taken with an advanced goniometer microscope (OCA20, DataPhysics) with external tilting device and SCA20 software for analyzing contact angles highly resolved with respect to time and spatial scales. The results obtained will be presented and the rolling-drop-criteria will be discussed.

  8. Renewable Water: Direct Contact Membrane Distillation Coupled With Solar Ponds

    NASA Astrophysics Data System (ADS)

    Suarez, F. I.; Tyler, S. W.; Childress, A. E.

    2010-12-01

    The exponential population growth and the accelerated increase in the standard of living have increased significantly the global consumption of two precious resources: water and energy. These resources are intrinsically linked and are required to allow a high quality of human life. With sufficient energy, water may be harvested from aquifers, treated for potable reuse, or desalinated from brackish and seawater supplies. Even though the costs of desalination have declined significantly, traditional desalination systems still require large quantities of energy, typically from fossil fuels that will not allow these systems to produce water in a sustainable way. Recent advances in direct contact membrane distillation can take advantage of low-quality or renewable heat to desalinate brackish water, seawater or wastewater. Direct contact membrane distillation operates at low pressures and can use small temperature differences between the feed and permeate water to achieve a significant freshwater production. Therefore, a much broader selection of energy sources can be considered to drive thermal desalination. A promising method for providing renewable source of heat for direct contact membrane distillation is a solar pond, which is an artificially stratified water body that captures solar radiation and stores it as thermal energy at the bottom of the pond. In this work, a direct contact membrane distillation/solar pond coupled system is modeled and tested using a laboratory-scale system. Freshwater production rates on the order of 2 L day-1 per m2 of solar pond (1 L hr-1 per m2 of membrane area) can easily be achieved with minimal operating costs and under low pressures. While these rates are modest, they are six times larger than those produced by other solar pond-powered desalination systems - and they are likely to be increased if heat losses in the laboratory-scale system are reduced. Even more, this system operates at much lower costs than traditional desalination

  9. 40 CFR 463.10 - Applicability; description of the contact cooling and heating water subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... processes in the contact cooling and heating water subcategory to waters of the United States and the introduction of such pollutants into publicly owned treatment works. Processes in the contact cooling and heating water subcategory are processes where process water comes in contact with plastic materials or...

  10. Contact sponge water absorption test implemented for in situ measures

    NASA Astrophysics Data System (ADS)

    Gaggero, Laura; Scrivano, Simona

    2016-04-01

    The contact sponge method is a non-destructive in-situ methodology used to estimate a water uptake coefficient. The procedure, unlike other in-situ measurement was proven to be directly comparable to the water uptake laboratory measurements, and was registered as UNI 11432:2011. The UNI Normal procedure requires to use a sponge with known density, soaked in water, weighed, placed on the material for 1 minute (UNI 11432, 2011; Pardini & Tiano, 2004), then weighed again. Difficulties arise in operating on test samples or on materials with porosity varied for decay. While carrying on the test, fluctuations in the bearing of the environmental parameters were negligible, but not the pressure applied to the surface, that induced the release of different water amounts towards the material. For this reason we designed a metal piece of the same diameter of the plate carrying the sponge, to be screwed at the tip of a pocket penetrometer. With this instrument the sponge was kept in contact with the surface for 1 minute applying two different loads, at first pushed with 0.3 kg/cm2 in order to press the sponge, but not its holder, against the surface. Then, a load of 1.1 kg/ cm2 was applied, still avoiding deviating the load to the sponge holder. We applied both the current and our implemented method to determine the water absorption by contact sponge on 5 fresh rock types (4 limestones: Fine - and Coarse grained Pietra di Vicenza, Rosso Verona, Breccia Aurora, and the silicoclastic Macigno sandstone). The results show that 1) the current methodology imply manual skill and experience to produce a coherent set of data; the variable involved are in fact not only the imposed pressure but also the compression mechanics. 2) The control on the applied pressure allowed reproducible measurements. Moreover, 3) the use of a thicker sponge enabled to apply the method even on rougher surfaces, as the device holding the sponge is not in contact with the tested object. Finally, 4) the

  11. Factor XI and contact activation as targets for antithrombotic therapy.

    PubMed

    Gailani, D; Bane, C E; Gruber, A

    2015-08-01

    The most commonly used anticoagulants produce therapeutic antithrombotic effects either by inhibiting thrombin or factor Xa (FXa) or by lowering the plasma levels of the precursors of these key enzymes, prothrombin and FX. These drugs do not distinguish between thrombin generation contributing to thrombosis from thrombin generation required for hemostasis. Thus, anticoagulants increase bleeding risk, and many patients who would benefit from therapy go untreated because of comorbidities that place them at unacceptable risk for hemorrhage. Studies in animals demonstrate that components of the plasma contact activation system contribute to experimentally induced thrombosis, despite playing little or no role in hemostasis. Attention has focused on FXII, the zymogen of a protease (FXIIa) that initiates contact activation when blood is exposed to foreign surfaces, and FXI, the zymogen of the protease FXIa, which links contact activation to the thrombin generation mechanism. In the case of FXI, epidemiologic data indicate this protein contributes to stroke and venous thromboembolism, and perhaps myocardial infarction, in humans. A phase 2 trial showing that reduction of FXI may be more effective than low molecular weight heparin at preventing venous thrombosis during knee replacement surgery provides proof of concept for the premise that an antithrombotic effect can be uncoupled from an anticoagulant effect in humans by targeting components of contact activation. Here, we review data on the role of FXI and FXII in thrombosis and results of preclinical and human trials for therapies targeting these proteins.

  12. Water slippage versus contact angle: a quasiuniversal relationship.

    PubMed

    Huang, David M; Sendner, Christian; Horinek, Dominik; Netz, Roland R; Bocquet, Lydéric

    2008-11-28

    Using molecular dynamics simulations of an atomistic water model, we study the interfacial hydrodynamic slippage of water at various hydrophobic surfaces, both organic (silane monolayers) and inorganic (diamondlike and Lennard-Jones models). The measured slip lengths range from nanometers to tens of nanometers. Slip lengths on different surfaces are found to collapse nearly onto a single curve as a function of the static contact angle characterizing the surface wettability, thereby suggesting a quasiuniversal relationship. This dependence is rationalized on the basis of a simple scaling description of the fluid-solid friction at the microscopic level. The link between slippage and water depletion at hydrophobic surfaces is clarified. These results shed light on the controversy over experimental measurements of the slip length at smooth hydrophobic surfaces.

  13. 40 CFR 463.10 - Applicability; description of the contact cooling and heating water subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... contact cooling and heating water subcategory. 463.10 Section 463.10 Protection of Environment... FORMING POINT SOURCE CATEGORY Contact Cooling and Heating Water Subcategory § 463.10 Applicability; description of the contact cooling and heating water subcategory. This subpart applies to discharges...

  14. 40 CFR 463.10 - Applicability; description of the contact cooling and heating water subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... contact cooling and heating water subcategory. 463.10 Section 463.10 Protection of Environment... FORMING POINT SOURCE CATEGORY Contact Cooling and Heating Water Subcategory § 463.10 Applicability; description of the contact cooling and heating water subcategory. This subpart applies to discharges...

  15. Integrins in point contacts mediate cell spreading: factors that regulate integrin accumulation in point contacts vs. focal contacts

    PubMed Central

    1993-01-01

    We have studied the function and distribution of the alpha 1 beta 1, alpha 5 beta 1 and alpha 6 beta 1 heterodimers on type-1 astrocytes with antibodies specific for integrin subunits (alpha 1, alpha 5, alpha 6, and beta 1). The alpha 1 beta 1 heterodimer mediates adhesion to laminin and collagen, the alpha 5 beta 1 to fibronectin in an RGD- dependent manner. The alpha 5 beta 1 integrin is found in focal contacts in long-term cultures of well-spread astrocytes colocalizing with vinculin and the termini of actin stress fibers. alpha 1 beta 1 heterodimers can occasionally be found as small aggregates within focal contacts but they do not accumulate there. Instead, alpha 1 beta 1 integrins are found in punctate deposits called point contacts which are distributed over the upper and the lower cell surfaces whether laminin, collagen, fibronectin or polylysine is used as a substratum. Unlike focal contacts, point contacts contain clathrin but rarely codistribute with actin or vinculin. Two observations indicate that these point contacts are functional. First, mAb 3A3, directed against the rat alpha 1 subunit, inhibits the attachment of astrocytes to laminin and collagen. Second, during the spreading of astrocytes, a band of point contacts forms around the cell perimeter at a time when no focal contacts are visible. While alpha 1 beta 1 integrins are found only in point contacts in astrocytes, the alpha 6 beta 1 integrin, another laminin receptor, is localized within focal contacts. Moreover, alpha 1 beta 1 heterodimers accumulate in focal contacts in fibroblasts. Thus, the alpha subunit contributes, independent of its ligand, to functional integrin heterodimer accumulation in focal contacts or in point contacts. This accumulation varies among different cell types with apparently identical heterodimers as well as with the motile state (spreading vs. flattened) of the same cells. PMID:8416993

  16. Non-contact ACL Injuries: Mechanisms and Risk Factors

    PubMed Central

    Boden, Barry P.; Sheehan, Frances T.; Torg, Joseph S.; Hewett, Timothy E.

    2013-01-01

    Significant advances have recently been made in understanding the mechanisms involved in noncontact anterior cruciate ligament (ACL) injury. Most ACL injuries involve minimal to no contact. Female athletes sustain a two- to eightfold greater rate of injury than do their male counterparts. Recent videotape analyses demonstrate significant differences in average leg and trunk positions during injury compared with control subjects. These findings as well as those of cadaveric and MRI studies indicate that axial compressive forces are a critical component in noncontact ACL injury. A complete understanding of the forces and risk factors associated with noncontact ACL injury should lead to the development of improved preventive strategiess for this devastating injury. PMID:20810933

  17. Risk Factors for Contact Lens Bacterial Contamination During Continuous Wear

    PubMed Central

    Szczotka-Flynn, Loretta B.; Bajaksouzian, Saralee; Jacobs, Michael R.; Rimm, Alfred

    2009-01-01

    Purpose Microbial contamination of contact lenses is associated with corneal infection and inflammation. This study determined which microbiological, clinical and demographic factors are associated with bacterial contamination of a silicone hydrogel contact lens when worn for continuous wear. Methods Two hundred five normal subjects were enrolled in the Longitudinal Analysis of Silicone Hydrogel (LASH) Contact Lens Study and were fitted with lotrafilcon A lenses for monthly continuous wear and followed for 1 year. Lenses were aseptically removed after 1 week and 4 months of wear and cultured using an agar sandwich technique. Lids and conjunctiva were routinely cultured at baseline, and after 1 week and 4 months of continuous wear. Lenses and ocular sites were considered to have substantial microbial bioburden when they harbored pathogenic organisms or high levels of commensal organisms. Univariate and multivariate logistic regression analyses were conducted to examine whether substantial conjunctival or lid bioburden, subject demographics, lens wearing history, symptoms, and biomicroscopic signs were associated with lens bioburden. Results About one-third (32.4%) of subjects had substantial bacterial bioburden in either eye across multiple visits. Over half (53.2%) and about one-tenth (11.7%) of subjects had substantial lid and conjunctival bioburden, respectively, and 11.2% discontinued due to discomfort. The adjusted odds ratios (and 95% confidence intervals) for presence of substantial lens bioburden were 2.49 (1.17–5.30), 4.24 (1.45–12.40), and 4.11 (1.17–14.46) for substantial lid bioburden, substantial conjunctival bioburden, and lens discomfort, respectively. Conclusions Bacterial contamination of silicone hydrogel contact lenses is common during continuous wear. Substantial lens bioburden is associated with discomfort precluding successful continuous wear. The presence of substantial lid and conjunctival bioburden are associated with a 2.5 fold and

  18. [Preservatives as important etiologic factors of allergic contact dermatitis].

    PubMed

    Kręcisz, Beata; Chomiczewska-Skóra, Dorota; Kieć-Świerczyńska, Marta

    2015-01-01

    Preservatives present in cosmetics and other industrial products can cause allergic contact dermatitis. The aim of the study was to assess the frequency of allergy to selected preservatives in consecutive patients examined due to contact dermatitis in the Nofer Institute of Occupational Medicine, Łódź, and to establish whether individuals sensitized to formaldehyde react simultaneously to formaldehyde releasers. A group of 405 patients (308 females and 97 males) was examined in 2011-2013. In all participants patch tests with a series of 13 preservatives (paraben mix, formaldehyde, Quaternium 15, chloromethylisothiazolinone/methylisothiazolinone mix, methyldibromoglutaronitrile, diazolidinyl urea, imidazolidinyl urea, DMDM hydantoin, 2-bromo-2-nitropropane-1,3-diol, iodopropynyl butylcarbamate, benzalkonium chloride, sodium metabisulfite, produced by Chemotechnique Diagnostics, Sweden) were performed. Of the 405 patients 74 (including 52 females) showed positive results of patch tests. Contact allergy to at least 1 preservative was noted in 47 (11.6%) patients, including 34 (11%) females and 13 (13.4%) males. Methylisothiazolinone proved to be the most frequent sensitizer--4.7% (5.2% females, 3.1% males) while parabens, 2-bromo-2-nitropropane-1,3-diol and imidazolidinyl urea (0.2%) were found to be the least frequent. Fourteen (3.4%) participants, 10 women and 4 men, were allergic to formaldehyde and/or formaldehyde releasers. In 11 (78.6%) of them monovalent hypersensitivity was observed. In 13 (3.2% of the examined group) patients allergy to preservatives might have been of occupational origin. Preservatives, particularly isothiazolinones, are significant causal factors of allergic contact dermatitis, including occupational cases. Individuals sensitized to formaldehyde may react simultaneously to formaldehyde releasers, however, such reactions are relatively rare. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  19. Contacts between the factor TUF and RPG sequences.

    PubMed

    Vignais, M L; Huet, J; Buhler, J M; Sentenac, A

    1990-08-25

    The yeast TUF factor binds specifically to RPG-like sequences involved in multiple functions at enhancers, silencers, and telomeres. We have characterized the interaction of TUF with its optimal binding sequence, rpg-1 (1-ACACCCATACATTT-14), using a gel DNA-binding assay in combination with methylation protection and mutagenesis experiments. As many as 10 base pairs appear to be engaged in factor binding. Analysis of a collection of 30 different RPG mutants demonstrated the importance of 8 base pairs at position 2, 3, 4, 5, 6, 7, 10, and 12 and the critical role of the central GC pair at position 5. Methylation protection data on four different natural sites confirmed a close contact at positions 4, 5, 6, and 10 and suggested additional contacts at base pairs 8, 12, and 13. The derived consensus sequence was RCAAYCCRYNCAYY. A quantitative band shift analysis was used to determine the equilibrium dissociation constant for the complex of TUF and its optimal binding site rpg-1. The specific dissociation constant (K8) was found to be 1.3 x 10(-11) M. The comparison of the K8 value with the dissociation constant obtained for nonspecific DNA sites (Kn8 = 8.7 x 10(-6) M) shows the high binding selectivity of TUF for its specific RPG target.

  20. Treatment, Material, Care, and Patient-Factors in Contact Lens-Related Dry Eye

    PubMed Central

    Ramamoorthy, Padmapriya; Sinnott, Loraine T.; Nichols, Jason J.

    2009-01-01

    PURPOSE To examine the effect of general contact lens and material characteristics, care solutions, treatment and patient-related factors on contact lens-related dry eye. METHODS The data were derived from the Contact Lens and Dry Eye Study, designed as a cross-sectional and nested case-control study including 360 subjects. In separate statistical models, logistic regression was used to examine general contact lens characteristics, specific hydrogel lens materials, care solutions, and patient-related factors associated with dry eye status (controlled for age, gender, and current treatments). RESULTS Several factors were significantly associated with dry eye, including treatment factors such as a recent contact lens refitting (OR = 5.75, 95% CI = 2.14 to 15.46) and use of artificial tears/rewetting drops (OR = 1.09, 95% CI = 1.02 to 1.16), and currently worn materials including FDA group II (OR = 2.98, 95% CI = 1.14 to 6.19) and IV (OR = 1.87, 95% CI = 1.08 to 3.24). Significant patient-related factors included decreased overall satisfaction (OR = 3.57, 95% CI = 2.08 to 5.88,), dry eye in the absence of contact lens wear (OR = 6.54, 95% CI = 2.57 to 16.62), reduced daily lens wear duration (OR = 1.16, 95% CI = 1.06 to 1.26), and reduced ability to wear lenses as long as desired (OR = 2.44, 95% CI = 1.30 to 4.54). Care solutions were not significant. CONCLUSIONS The strong association of common treatment factors with dry eye status in contact lens wearers suggests that these treatments are not entirely effective. The use of high water content materials was strongly related to dry eye in lens wearers, while care solutions were not. Contact lens-related dry eye was also associated with several patient-related factors such as greater ocular discomfort (without lenses), dissatisfaction, and inability to wear lenses for desired durations. PMID:18677240

  1. Exposure to Schistosoma mansoni infection in a rural area in Brazil. Part III: household aggregation of water-contact behaviour.

    PubMed

    Bethony, Jeffrey; Williams, Jeff T; Brooker, Simon; Gazzinelli, Andrea; Gazzinelli, Maria F; LoVerde, Philip T; Corrêa-Oliveira, Rodrigo; Kloos, Helmut

    2004-03-01

    Much research points to the importance of the household in the study of water-borne diseases such as schistosomiasis. An important aspect of the household is the clustering of domestic activities associated with water collection, storage and usage. Such activities can result in the sharing of water-contact sites and water-contact behaviour, which expose household members to similar risks of infection. In previous studies, we determined that shared residence accounted for 28% of the variance in Schistosoma faecal egg excretion rates. We now quantify the effect of shared residence on the variation in water-related health behaviours. We found that shared residence accounted for 30% of the variation in total water contacts per week. It also accounted for a large proportion of the variation in individual water-contact behaviour: e.g. agricultural contacts (63%), washing limbs (56%) or bathing (41%). These results implicate the household as an important composite measure of the complex relationships between socioeconomic, environmental and behavioural factors that influence water-contact behaviour and, therefore, the transmission of schistosomiasis. Our results also support a focus on the household in the implementation of schistosomiasis prevention and control efforts.

  2. All-atom contact model for understanding protein dynamics from crystallographic B-factors.

    PubMed

    Li, Da-Wei; Brüschweiler, Rafael

    2009-04-22

    An all-atom local contact model is described that can be used to predict protein motions underlying isotropic crystallographic B-factors. It uses a mean-field approximation to represent the motion of an atom in a harmonic potential generated by the surrounding atoms resting at their equilibrium positions. Based on a 400-ns molecular dynamics simulation of ubiquitin in explicit water, it is found that each surrounding atom stiffens the spring constant by a term that on average scales exponentially with the interatomic distance. This model combines features of the local density model by Halle and the local contact model by Zhang and Brüschweiler. When applied to a nonredundant set of 98 ultra-high resolution protein structures, an average correlation coefficient of 0.75 is obtained for all atoms. The systematic inclusion of crystal contact contributions and fraying effects is found to enhance the performance substantially. Because the computational cost of the local contact model scales linearly with the number of protein atoms, it is applicable to proteins of any size for the prediction of B-factors of both backbone and side-chain atoms. The model performs as well as or better than several other models tested, such as rigid-body motional models, the local density model, and various forms of the elastic network model. It is concluded that at the currently achievable level of accuracy, collective intramolecular motions are not essential for the interpretation of B-factors.

  3. Superhydrophobic polyethylcyanoacrylate coatings. Contact area with water measured by Raman spectral images, contact angle and Cassie-Baxter model.

    PubMed

    Bonugli, L O; dos Santos, M V Puydinger; de Souza, E F; Teschke, O

    2012-12-15

    Apolar fibers wired into a mesh-like microstructure forming a coating with a contact angle larger than 160° and fabricated by polycyanoacrylate polymerization are described. Interconnected fibers with diameters measuring approximately 5 μm are formed by texturized linear or folded nanowires. The structure forming the deposited film occupies ~1.5% of the coating's top geometric area. This value agrees with the water/coating contact area given by the Cassie-Baxter contact-angle model (~1.5%). The spatial distribution of the surface in contact with water was determined by Raman spectral imaging (~1.5%) using the polycyanoacrylate lines and by scanning electron microscopy (~2.0%).

  4. Static and dynamic contact angles of water droplet on a solid surface using molecular dynamics simulation.

    PubMed

    Hong, Seung Do; Ha, Man Yeong; Balachandar, S

    2009-11-01

    The present study investigates the variation of static contact angle of a water droplet in equilibrium with a solid surface in the absence of a body force and the dynamic contact angles of water droplet moving on a solid surface for different characteristic energies using the molecular dynamics simulation. With increasing characteristic energy, the static contact angle in equilibrium with a solid surface in the absence of a body force decreases because the hydrophobic surface changes its characteristics to the hydrophilic surface. In order to consider the effect of moving water droplet on the dynamic contact angles, we apply the constant acceleration to an individual oxygen and hydrogen atom. In the presence of a body force, the water droplet changes its shape with larger advancing contact angle than the receding angle. The dynamic contact angles are compared with the static contact angle in order to see the effect of the presence of a body force.

  5. Interdomain contacts control folding of transcription factor RfaH

    PubMed Central

    Tomar, Sushil Kumar; Knauer, Stefan H.; NandyMazumdar, Monali; Rösch, Paul; Artsimovitch, Irina

    2013-01-01

    Escherichia coli RfaH activates gene expression by tethering the elongating RNA polymerase to the ribosome. This bridging action requires a complete refolding of the RfaH C-terminal domain (CTD) from an α-helical hairpin, which binds to the N-terminal domain (NTD) in the free protein, to a β-barrel, which interacts with the ribosomal protein S10 following RfaH recruitment to its target operons. The CTD forms a β-barrel when expressed alone or proteolytically separated from the NTD, indicating that the α-helical state is trapped by the NTD, perhaps co-translationally. Alternatively, the interdomain contacts may be sufficient to drive the formation of the α-helical form. Here, we use functional and NMR analyses to show that the denatured RfaH refolds into the native state and that RfaH in which the order of the domains is reversed is fully functional in vitro and in vivo. Our results indicate that all information necessary to determine its fold is encoded within RfaH itself, whereas accessory factors or sequential folding of NTD and CTD during translation are dispensable. These findings suggest that universally conserved RfaH homologs may change folds to accommodate diverse interaction partners and that context-dependent protein refolding may be widespread in nature. PMID:23990324

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

    NASA Astrophysics Data System (ADS)

    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. Contact resonance atomic force microscopy imaging in air and water using photothermal excitation

    SciTech Connect

    Kocun, Marta; Labuda, Aleksander; Gannepalli, Anil; Proksch, Roger

    2015-08-15

    Contact Resonance Force Microscopy (CR-FM) is a leading atomic force microscopy technique for measuring viscoelastic nano-mechanical properties. Conventional piezo-excited CR-FM measurements have been limited to imaging in air, since the “forest of peaks” frequency response associated with acoustic excitation methods effectively masks the true cantilever resonance. Using photothermal excitation results in clean contact, resonance spectra that closely match the ideal frequency response of the cantilever, allowing unambiguous and simple resonance frequency and quality factor measurements in air and liquids alike. This extends the capabilities of CR-FM to biologically relevant and other soft samples in liquid environments. We demonstrate CR-FM in air and water on both stiff silicon/titanium samples and softer polystyrene-polyethylene-polypropylene polymer samples with the quantitative moduli having very good agreement between expected and measured values.

  8. Contact resonance atomic force microscopy imaging in air and water using photothermal excitation.

    PubMed

    Kocun, Marta; Labuda, Aleksander; Gannepalli, Anil; Proksch, Roger

    2015-08-01

    Contact Resonance Force Microscopy (CR-FM) is a leading atomic force microscopy technique for measuring viscoelastic nano-mechanical properties. Conventional piezo-excited CR-FM measurements have been limited to imaging in air, since the "forest of peaks" frequency response associated with acoustic excitation methods effectively masks the true cantilever resonance. Using photothermal excitation results in clean contact, resonance spectra that closely match the ideal frequency response of the cantilever, allowing unambiguous and simple resonance frequency and quality factor measurements in air and liquids alike. This extends the capabilities of CR-FM to biologically relevant and other soft samples in liquid environments. We demonstrate CR-FM in air and water on both stiff silicon/titanium samples and softer polystyrene-polyethylene-polypropylene polymer samples with the quantitative moduli having very good agreement between expected and measured values.

  9. Investigating How Contact Angle Effects the Interaction between Water and a Hydrophobic Surface

    NASA Astrophysics Data System (ADS)

    Poynor, Adele; Neidig, Caitlyn

    2012-02-01

    By definition hydrophobic substances hate water. What happens when water is forced into contact with a hydrophobic surface? One theory is that an ultra-thin low-density region forms near the surface. Contact angle is a measure of how hydrophobic a surface is. We have employed an automated home-built Surface Plasmon Resonance (SPR) apparatus to investigate the effect of varying the contact angle on the depletion layer

  10. Risk factors for tuberculosis in contact investigations in Rotterdam, the Netherlands

    PubMed Central

    Verdier, Jesse Eduard; Jan de Vlas, Sake; Kidgell-Koppelaar, Inge D.; Richardus, Jan Hendrik

    2012-01-01

    Contact investigations around tuberculosis patients enable early detection of infection and disease, and prevention of secondary tuberculosis cases. We aim to identify risk factors for M. tuberculosis transmission to contacts of tuberculosis patients, based on unique data from routine contact investigations by the Public Health Service in Rotterdam, the Netherlands, collected between 2001 and 2006. Through logistic regression analysis, we determined the effect of various risk factors on the chance of finding a latent tuberculosis (TB) infection or overt tuberculosis case among contacts. A total of 1165 index patients with active tuberculosis were registered and at least one contact was investigated in 731, resulting in 21,540 contacts overall. Altogether, the contact investigations led to 91 cases of active tuberculosis. Of the 12,698 contacts eligible for screening by tuberculin skin test, 1091 (9%) were diagnosed with latent tuberculosis infections. Risk factors were old age of the contact, old age of the index patient, and the relationship to the index. A larger fraction of infected close contacts was strongly associated with infections among more distant contacts. Our findings emphasize the importance of including these personal and interpersonal risk factors in decision making in contact investigations. PMID:24470940

  11. Discovery and assessment of water soluble coumarins as inhibitors of the coagulation contact pathway.

    PubMed

    Bouckaert, Charlotte; Zhu, Shu; Govers-Riemslag, José W P; Depoorter, Maxime; Diamond, Scott L; Pochet, Lionel

    2017-09-01

    Over the last decade, the coagulation factor XIIa (FXIIa) has seen renewed interest as a therapeutic target. Indeed, its inhibition could offer a protection against thrombosis without increasing the risk of bleeding. Moreover, it could answer the need for a safe prevention of blood-contacting medical devices-related thrombosis. Among the FXII and FXIIa inhibitors already described in literature, organic small-molecular-weight inhibitors are rather left behind. In this study, we were focused on the discovery and assessment of water soluble small molecules. First, a search within our library of compounds flagged two promising hits. Indeed, enzymes and plasma assays suggested they have a greater activity on the contact factors (FXIa, plasma kallikrein and FXIIa) than on the TF pathway. Then, simple pharmacomodulations were undertaken with the aim to design more selective FXIIa inhibitors. This afforded compounds having different degrees of selectivity. All compounds were finally screened in whole blood using an 8-channel microfluidic model and thromboelastometry measurements. Interestingly, all molecules interfered with the thrombus formation and one of them could be considered as a small organic contact inhibitor. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Importance of Water Content of the Stratum Corneum in Mouse Models for Contact Hypersensitivity.

    PubMed

    Doi, Takaaki; Mizukawa, Yoshiko; Shimoda, Yurie; Yamazaki, Yoshimi; Shiohara, Tetsuo

    2017-01-01

    Although a marked rise in the prevalence of allergic diseases over the past few decades may be related to environmental factors in industrialized countries, evidence for the protective effect of humidity on the barrier function of the skin is still awaited. We asked whether an increase in the water content of stratum corneum at the site of hapten application had a strong impact on the magnitude of contact hypersensitivity (CHS). The magnitude of CHS, induced by either lipid-soluble or water-soluble hapten, was inversely correlated with the water content of stratum corneum at the hapten application site in the elicitation phase. An increase in the water content induced by exposure to high humidity for 6 hours was sufficient to ameliorate the magnitude of CHS even in mice with the genetic defect in attenuating the CHS responses, such as flaky tail mice. The reduced CHS was associated with downregulation of IL-1α, IL-4, and IFN-γ mRNA expression. Epicutaneously applied hapten can penetrate more readily through the stratum corneum with lower water content than that with higher water content, even after tape-stripping. These findings indicate that increased levels of water in the stratum corneum serve to ameliorate the CHS beyond the genetic effects. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Recreational Water Contact and Fish Consumption Assessment to Inform Risk Estimates and Evaluate Ecosystem Services

    EPA Science Inventory

    Background: Surface waters provide invaluable ecosystem services, including drinking water, food, waste water disposal, and recreation. The nature and frequency of recreational contact with surface waters is a critical consideration in evaluating benefits to human well-being (e.g...

  14. Recreational Water Contact and Fish Consumption Assessment to Inform Risk Estimates and Evaluate Ecosystem Services

    EPA Science Inventory

    Background: Surface waters provide invaluable ecosystem services, including drinking water, food, waste water disposal, and recreation. The nature and frequency of recreational contact with surface waters is a critical consideration in evaluating benefits to human well-being (e.g...

  15. Analysis of long-term durability of superhydrophobic properties under continuous contact with water.

    PubMed

    Boinovich, Ludmila; Emelyanenko, Alexandre M; Pashinin, Andrei S

    2010-06-01

    In view of more and more extending areas of application of hydrophobic and superhydrophobic materials and coatings, the problem of degradation of superhydrophobic state becomes extremely important. In this paper, the results of studies of time evolution of water contact angle on some siloxane-based hydrophobic and superhydrophobic surfaces in the conditions of long-term continuous contact with water are presented. Different mechanisms responsible for reversible and nonreversible deterioration of contact angle values were discussed and experimentally verified. We noted that evolution of water contact angle in time in the conditions of continuous contact with water needs to be considered when studying the durability of superhydrophobic coating because of its high sensitivity to the state of the coating and the details of its chemical structure.

  16. Research on Outer Factor Affecting the Freezing of Supercooled Water

    NASA Astrophysics Data System (ADS)

    Saito, Akio; Okawa, Seiji; Une, Hiroshi; Tanogashira, Ken'ichi; Tojiki, Akira

    In relation to the problem of supercooling for ice storage devices, various kinds of experiments were carried out to find some factors which control the supercooling phenomenon. Convection due to rotating solid in water, stirring, vibration, shock, rubbing glass with glass in water and collision of solid in water were selected as outer factors. It was found that factors such as convection, stirring, vibration, non-contacting shock have no effect on freezing supercooled water. They seem to be just adding some positive energy to water. On the other hand, collision or rubbing between solids or solid and liquid surface helps supercooled water to freeze. We believe that making water molecules closer to each other, whose motion were restricted by solid or liquid surface, induce the growth of ice embryo.

  17. Humidity-conditioned gravimetric method to measure the water content of hydrogel contact lens materials.

    PubMed

    Galas, S L; Enns, J B

    1993-07-01

    A method to determine the humidity-conditioned gravimetric water content of hydrogel contact lens materials has been developed, in which errors due to blotting have been eliminated by conditioning the lens in a series of relative humidity (RH) environments before measuring the water content gravimetrically, and then extrapolating the water content to 100% RH. This method has been used to determine the water contents of representative materials from each of the four FDA lens groups, which were compared with their labeled values, as well as with values obtained from refractive index measurements. The deviation of the water content of soft contact lenses as measured by refractive index from that obtained gravimetrically increased as the water content decreased. The humidity-conditioned gravimetric method to determine water content of hydrophilic contact lenses is being proposed as an International Organization for Standardization (ISO) standard, as an improvement over the gravimetric and refractive index methods.

  18. Back contacted and small form factor GAAS solar cell.

    SciTech Connect

    Clews, Peggy Jane; Wanlass, Mark W.; Sanchez, Carlos A.; Pluym, Tammy; Cruz-Campa, Jose Luis; Okandan, Murat; Gupta, Vipin P.; Nielson, Gregory N.; Resnick, Paul James

    2010-06-01

    We present a newly developed microsystem enabled, back-contacted, shade-free GaAs solar cell. Using microsystem tools, we created sturdy 3 {micro}m thick devices with lateral dimensions of 250 {micro}m, 500 {micro}m, 1 mm, and 2 mm. The fabrication procedure and the results of characterization tests are discussed. The highest efficiency cell had a lateral size of 500 {micro}m and a conversion efficiency of 10%, open circuit voltage of 0.9 V and a current density of 14.9 mA/cm{sup 2} under one-sun illumination.

  19. Water flow in soil and plants: the importance of good contacts

    NASA Astrophysics Data System (ADS)

    Carminati, A.

    2009-04-01

    Water flow in unsaturated porous media is controlled by the continuity of the liquid phase through the pore system. In many cases, the pore system is composed of regions with different material properties separated by interfaces containing macro-pores or gaps that are easily drained. When these gaps are drained the continuity of the liquid flow path may break, with a consequent decrease in the conductivity of the medium. We present two examples demonstrating the controlling role of interfaces on water flow. The first example describes an aggregated soil. Due to the aggregate roughness, the inter-aggregate contacts contain macro-pores which are rapidly drained. The hydraulic behavior of contacts varies from highly conductive when water fills the contact to a bottle-neck to flow as water pressure drops and contact asperities rapidly drained. The conductivity of the system is determined by the water-filled contact area between aggregates, rather then by the average volumetric water content. The second example refers to the contacts between soil and roots. By means of X-ray tomography we showed that during periods of drought, roots shrink and may lose contact with the soil, with a consequent reduction in water uptake. When the soil is irrigated again, roots swell partially refilling the gaps. Opening and closing of gaps may help plant to optimize water use, to prevent water loss when soil dries, and to restore the soil-root continuity after irrigation. Additionally, soil-root continuity is improved by root exudates and root hairs, which make the soil-root interface a complex and dynamic biomaterial with specific and unique properties. These two examples show that interfaces between heterogeneous media can have a big impact on water flow in porous media and demonstrate that volumetric averaging for predicting transport properties can lead to wrong results. An approach based on flow cross sections and interfacial properties may be the way to a deeper understanding and

  20. Dissolution-induced contact angle modification in dense nonaqueous phase liquid/water systems.

    PubMed

    Mohammad, Orphius I; Kibbey, Tohren C G

    2005-03-15

    The contact angle between DNAPL, water, and aquifer material interfaces influences the spatial distribution of DNAPLs as they infiltrate into the aquifer, and may ultimately influence their remediation. The objective of this work was to evaluate the effects of dissolution on contact angle. Just as physically retracting a sessile drop reduces its contact angle with a surface, it was speculated that dissolution could cause contact angles to be reduced. Long-term dissolution experiments were conducted over the course of days to weeks, examining the dissolution of sessile drops of two DNAPLs, trichloroethylene (TCE) and tetrachloroethylene (PCE), in water and low concentration surfactant solutions, on glass surfaces. Experiments found that dissolution led to a continuous decrease of contact angle measured through the DNAPL drop, in most cases to near 0 degrees, far lower than angles achievable through measurements of receding contact angles for the same systems. Pinning of drop contact diameter was observed in most experiments. A model developed on the basis of the Bashforth-Adams equation to predict the effect of dissolution on contact angle for drops with a pinned contact diameter showed very good agreement with experimental observations.

  1. [Hygienic requirements on materials in contact with drinking water].

    PubMed

    Schlosser, F-U; Schuster, R; Rapp, T

    2007-03-01

    In Germany the hygienic requirements on materials used to supply drinking water are a part of the technical standards. These regulations have to ensure that legal requirements on drinking water are met at the tap. The hygienic harmlessness is assured by requirements on the composition of materials and by test procedures including parametric limits. Historically, the requirements on different types of materials are a part of different technical standards.

  2. The rose petal effect and the role of advancing water contact angles for drop confinement

    NASA Astrophysics Data System (ADS)

    Kofoed Mandsberg, Nikolaj; Taboryski, Rafael

    2017-06-01

    We studied the role of advancing water contact angles on superhydrophobic surfaces that exhibited strong pinning effects as known in nature from rose petals. Textured surfaces were engineered in silicon by lithographical techniques. The textures were comprised of hexagonal microstructures superimposed with randomly distributed nanospikes and were coated with a hydrophobic fluorocarbon agent. A step in the advancing water contact angle bounding specific areas was obtained by engineering a corresponding topographic step in the hexagonal micro-texture. This enabled a surface texture design confining drops to areas with a lower advancing contact angle.

  3. The role of domestic tap water on Acanthamoeba keratitis in non-contact lens wearers and validation of laboratory methods.

    PubMed

    Koltas, Ismail Soner; Eroglu, Fadime; Erdem, Elif; Yagmur, Meltem; Tanır, Ferdi

    2015-09-01

    Acanthamoeba is increasingly recognized as an important cause of keratitis in non-contact lens wearers while contact lens wear is the leading risk factor for Acanthamoeba keratitis (AK). It is unlikely that the Acanthamoeba colonization is a feature which is effective only in patient's homes with infectious keratitis since the organism has been isolated from domestic tap water. Two hundred and thirty-one (231) corneal scrapings were taken from infectious keratitis cases, and four contact lens solutions and domestic tap waters were taken from 22 out of 44 AK-diagnosed patient's homes. Microscopic examination, culture, PCR, real-time PCR and DNA sequencing analyses were used for AK-diagnosed samples. The real-time PCR was the most sensitive (100 %) one among the methods used in diagnosis of AK. The 44 (19.0 %) out of 231 corneal scrapings, 4/4 (100 %) contact lens solution and 11/22 (50 %) of domestic tap water samples were found to be positive by real-time PCR for Acanthamoeba. A. griffini (T3), A. castellanii (T4) and A. jacobsi (T15) genotypes were obtained from corneal scrapings, contact lens solutions and domestic tap water samples taken from the patient's homes diagnosed with AK. The isolation of Acanthamoeba containing 6/22 (27.3 %) A. griffini (T3), 14/22 (63.6 %) A. castellanii (T4) and 2/22 (9.1 %) A. jacobsi (T15) from the domestic tap water outlets of 22 of 44 (50 %) of patient's homes revealed that is a significant source of these organisms. A. griffini (T3) and A. jacobsi (T15) genotypes have not been determined from AK cases in Turkey previously. Thus, we conclude that Acanthamoeba keratitis is associated with exposition of patients who has ocular trauma or ocular surface disease to domestic tap water in endemic or potentially endemic countries.

  4. [Water contacts in dracunculiasis-infected patients in Mali: transmission risk activities].

    PubMed

    Etard, J F; Kodio, B; Traoré, S; Audibert, M

    2002-11-01

    The aim of this study lies in the identification of human activities responsible for the transmission of the Guinea worm in an endemic village in Diema Region in Mali. Human water contacts observations started after a census followed by the implementation of a bi-monthly notification system, carried out from May to November 1993. Water contacts were noticed and observed from the mid-July to the end of November of the same year. The first case of dracunculiasis observed was randomly drawn out of a list of the families with obvious cases. The patent case activities involving either surface water, traditional wells or bore-hole water were recorded for 10 consecutive days. During this observation period, contacts made by other patients with the same water sources were also recorded. After 14 days, the case list was updated and a new case selected out of families previously selected. This cycle was repeated until the end of the study period. A "contact at risk for transmission" was defined by a close correspondence between the location of the worm's emergence and the surface of the skin exposed to water, within two weeks following emergence. Contacts were described according to water sources, activities in relation to water, date, gender and age. Observations were made on 103 patients who had 2506 activities in relation with a water body: 1132 of these activities implied a skin contact with the water. Only 133 (9%) of these water contacts were at risk for transmission, 75% took place during the months of August and September, 80% were related to surface waters and 20% to traditional wells. Woman household activities and boys games were the major activities at risk, in contrast to economic activities (watering cattle). The low proportion of "at risk activities" evaluated in this study suggests that a small number of water contacts is sufficient to maintain the transmission. The case implications of the current eradication strategy might not be sufficient alone to break

  5. Fractional Wetting and Contact Angle Dynamics in Water Repellent Soils

    NASA Astrophysics Data System (ADS)

    Beatty, S. M.; Smith, J. E.

    2009-12-01

    Soil water repellency is a vadose zone phenomenon most often associated with reduced or impeded infiltration for some time. Even if only short-lived, problems caused by soil water repellency are numerous and significant. In recent years, a substantial interdisciplinary research effort has advanced our knowledge of soil water behavior in these highly complex and non-linear hydrologic systems. However, fundamental understanding of the interdependent relationship between static conditions and dynamic processes is still largely undeveloped. In this study we used Axisymmetric Drop Shape Analysis (ADSA) and instrumented infiltration experiments to systematically measure and quantify static controls and dynamic processes in hydrophobic media. Using natural materials collected from a wildfire site approximately 1.5 years post-fire, we show that infiltration processes within these materials are largely governed by the spatial and temporal variation of wettable and non-wettable fractions. The approach taken 1) facilitated the development of our understanding of the interdependent nature of static and dynamic variables on soil water behavior in these materials and 2) indicates that the dynamic nature of these hydrophobic materials is well expressed empirically over centimeter spatial scales and temporal scales on the order of 10’s of minutes to hours.

  6. Contact-line dynamics for water waves and high-Re flows

    NASA Astrophysics Data System (ADS)

    Jiang, Lei; Liu, Ziyuan; Perlin, Marc; Schultz, William W.

    1997-11-01

    An appropriate contact-line model at the gas/liquid/solid trijunction is critical to the prediction of both low-Re flows and high-Re flows such as occur with water waves. Contact-line condition for water waves was proposed by Hocking (1987) and later by Miles (1991) based on Navier's slip relation. However, Cocciaro et al. (1993) and Ting & Perlin (1995) showed that strongly nonlinear contact-line dynamics are present experimentally, and that these dynamics are more complex than Hocking and Miles' models. We present results on the frequency and damping of Faraday water waves in various wave tanks and under different wetting conditions. The surface-elevation decay is analyzed with a complex demodulation technique. Frequency detuning and contact-line damping are found to obey power laws in the wave amplitude. The power-law exponent depends on the wetting condition and the material of which the tank is constructed. A preliminary analysis suggests that an averaged contact-line condition similar to the Tanner's law gives the correct amplitude dependence in frequency and damping. This condition also agrees qualitatively with contact-line data from Ting & Perlin. Preliminary analysis of the boundary layer structure near a moving contact line is carried out in the large-Re limit. Influence of corner flow and some implications from the self-similar Falkner-Skan equation are presented. This research is supported by ONR and NASA Microgravity Fluid Physics Program.

  7. Contact angle measurement - a reliable supportive method for screening water-resistance of ultraviolet-protecting products in vivo.

    PubMed

    Hagens, R; Mann, T; Schreiner, V; Barlag, H G; Wenck, H; Wittern, K-P; Mei, W

    2007-08-01

    Substantivity of sunscreen formulations is affected by the wash-out rate of ultraviolet-absorber and -reflector compounds in water. Water-resistance of sunscreen formulations is currently determined according to a standardized European Cosmetic Toiletry and Perfumery Association (COLIPA) protocol, encompassing the determination of a minimal erythemal dose before and after a defined immersion step in water. It can be supposed that the higher the wettability of a treated skin area, the higher is the wash-out rate of sunscreen compounds. This present report addresses the validity of determining the wettability of treated skin alone as a measure for the water-resistance of sunscreen products. The report addresses the robustness, accuracy and congruence of a recently developed wettability test, based on the measurement of the contact angle (CA) of a sessile water drop on treated skin areas. Contact angle data of 66 sunscreen formulations are compared with the corresponding results of 81 water-resistance tests, using the sun protection factor (SPF)/immersion/SPF method. Sunscreen products tested by the CA method were applied to the skin of the volar forearm of test subjects at a defined dose and drying-time, using a standardized application and recording device. Contact angles between a sessile water drop and skin were recorded by a Charge-Coupled Device (CCD) camera and subjected to automatic contour analysis. Taking the SPF/immersion/SPF method as gold standard, accuracy parameters of the CA method were determined. By using an appropriate cut-off level of CAs, the CA method has a specificity and positive-predictive value of 100%, and turns out to be a reliable screening method to identify water-resistant formulations. Based on our findings, those formulations that give CAs above 30 degrees may be categorized water-proof without further testing by the COLIPA water-resistance method.

  8. 40 CFR 463.10 - Applicability; description of the contact cooling and heating water subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) PLASTICS MOLDING AND... cooling and heating water subcategory are processes where process water comes in contact with plastic materials or plastic products for the purpose of heat transfer during plastics molding and forming....

  9. 40 CFR 463.10 - Applicability; description of the contact cooling and heating water subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS PLASTICS MOLDING AND FORMING POINT... heating water subcategory are processes where process water comes in contact with plastic materials or plastic products for the purpose of heat transfer during plastics molding and forming....

  10. Water in Contact with a Cationic Lipid Exhibits Bulklike Vibrational Dynamics.

    PubMed

    Livingstone, Ruth A; Zhang, Zhen; Piatkowski, Lukasz; Bakker, Huib J; Hunger, Johannes; Bonn, Mischa; Backus, Ellen H G

    2016-09-16

    Water in contact with lipids is an important aspect of most biological systems and has been termed "biological water". We used time-resolved infrared spectroscopy to investigate the vibrational dynamics of lipid-bound water molecules, to shed more light on the properties of these important molecules. We studied water in contact with a positively charged lipid monolayer using surface-specific two-dimensional sum frequency generation vibrational spectroscopy with subpicosecond time resolution. The dynamics of the O-D stretch vibration was measured for both pure D2O and isotopically diluted D2O under a monolayer of 1,2-dipalmitoyl-3-trimethylammonium-propane. It was found that the lifetime of the stretch vibration depends on the excitation frequency and that efficient energy transfer occurs between the interfacial water molecules. The spectral diffusion and vibrational relaxation of the stretch vibration were successfully explained with a simple model, taking into account the Förster transfer between stretch vibrations and vibrational relaxation via the bend overtone. These observations are very similar to those made for bulk water and as such lead us to conclude that water at a positively charged lipid interface behaves similarly to bulk water. This contrasts the behavior of water in contact with negative or zwitterionic lipids and can be understood by noting that for cationic lipids the charge-induced alignment of water molecules results in interfacial water molecules with O-D groups pointing toward the bulk.

  11. What Governs Friction of Silicon Oxide in Humid Environment: Contact Area between Solids, Water Meniscus around the Contact, or Water Layer Structure?

    PubMed

    Chen, Lei; Xiao, Chen; Yu, Bingjun; Kim, Seong H; Qian, Linmao

    2017-09-26

    In order to understand the interfacial parameters governing the friction force (Ft) between silicon oxide surfaces in humid environment, the sliding speed (v) and relative humidity (RH) dependences of Ft were measured for a silica sphere (1 μm radius) sliding on a silicon oxide (SiOx) surface, using atomic force microscopy (AFM), and analyzed with a mathematical model describing interfacial contacts under a dynamic condition. Generally, Ft decreases logarithmically with increasing v to a cutoff value below which its dependence on interfacial chemistry and sliding condition is relatively weak. Above the cutoff value, the logarithmic v dependence could be divided into two regimes: (i) when RH is lower than 50%, Ft is a function of both v and RH; (ii) in contrast, at RH ≥ 50%, Ft is a function of v only, but not RH. These complicated v and RH dependences were hypothesized to originate from the structure of the water layer adsorbed on the surface and the water meniscus around the annulus of the contact area. This hypothesis was tested by analyzing Ft as a function of the water meniscus area (Am) and volume (Vm) estimated from a thermally activated water-bridge formation model. Surprisingly, it was found that Ft varies linearly with Vm and correlates poorly with Am at RH < 50%; and then its Vm dependence becomes weaker as RH increases above 50%. Comparing the friction data with the attenuated total reflection infrared (ATR-IR) spectroscopy analysis result of the adsorbed water layer, it appeared that the solidlike water layer structure formed on the silica surface plays a critical role in friction at RH < 50% and its contribution diminishes at RH ≥ 50%. These findings give a deeper insight into the role of water condensation in friction of the silicon oxide single asperity contact under ambient conditions.

  12. Interpreting contact angle results under air, water and oil for the same surfaces

    NASA Astrophysics Data System (ADS)

    Ozkan, Orkun; Yildirim Erbil, H.

    2017-06-01

    Under-water and under-oil superhydropobicity and superhydrophilicity have gained significant attention over the last few years. In this study, contact angles on five flat surfaces (polypropylene, poly(methyl methacrylate), polycarbonate, TEFLON-FEP and glass slide) were measured in water drop-in-air, air bubble-under-water, oil drop-in-air, air bubble-under-oil, oil drop-under-water and water drop-under-oil conditions. Heptane, octane, nonane, decane, dodecane, and hexadecane hydrocarbons were used as oils. Immiscible water/oil pairs were previously mutually saturated to provide thermodynamical equilibrium conditions and their surface and interfacial tensions were determined experimentally. These pairs were used in the two-liquid contact angle measurements. Surface free energies of the solid surfaces in air were determined independently by using the van Oss-Good method, using the contact angle results of pure water, ethylene glycol, formamide, methylene iodide and α-bromonaphalene. In addition, Zisman’s ‘critical surface tension’ values were also determined for comparison. In theory, the summation of contact angle results in a complementary case would give a total of 180° for ideal surfaces. However, it was determined that there are large deviations from this rule in practical cases and these deviations depend on surface free energies of solids. Three complementary cases of (water-in-air with air bubble-under-water); (oil-in-air with air bubble-under-oil); and (oil-under-water with water-under-oil) were investigated in particular to determine the deviations from ideality. A novel approach, named ‘complementary hysteresis’ [γ WA(cosθ 1  -  cosθ 2) and γ OW(cosθ 6  -  cosθ 5)] was developed where γ WA and γ OW represent the interfacial tensions of water/air and oil/water, and θ 1, θ 2, θ 5, and θ 6 were the contact angles of water/air, air bubble/water, oil/water and water/oil respectively. It was experimentally determined that

  13. Do the factors associated with successful contact tracing of patients with gonorrhoea and Chlamydia differ?

    PubMed Central

    Ross, J. D.; Sukthankar, A.; Radcliffe, K. W.; Andre, J.

    1999-01-01

    OBJECTIVE: To assess and compare factors which may be associated with successful contact tracing in patients with gonorrhoea and chlamydia. STUDY DESIGN: Prospective observational study of patients attending a genitourinary medicine clinic with a diagnosis of gonorrhoea or chlamydia. Multivariate analysis model including demographic, socioeconomic, and behavioural variables. RESULTS: The attendance of at least one sexual contact was associated with naming more contacts for patients with gonorrhoea (OR 1.44, 95% CI 1.04-2.01). A history of gonorrhoea was associated with successful contact tracing for patients with chlamydia (OR 1.46, 95% CI 1.12-1.9). Successful contact tracing, as defined by at least one confirmed contact attendance after the index case, was not associated with age, sex, sexual orientation, history of chlamydia, use of condoms, marital status, ethnicity, or socioeconomic status for either gonorrhoea or chlamydia. CONCLUSIONS: Differences in the composition of the core groups infected with gonorrhoea and chlamydia are not explained by differences in contact tracing success. In the clinic setting studied, the outcome of contact tracing was not associated with a variety of demographic, socioeconomic, and behaviour factors. 


 PMID:10448364

  14. Estimating the Relative Role of Various Subcategories of Food, Water, and Animal Contact Transmission of 28 Enteric Diseases in Canada

    PubMed Central

    Butler, Ainslie J.; Thomas, M. Kate

    2016-01-01

    Abstract Objective: Enteric illness represents a significant burden of illness in Canada and internationally. Building on previous research, an expert elicitation was undertaken to explore the routes of transmission for 28 pathogens involved in enteric illness in Canada. This article considers the subcategories of foodborne, waterborne, and animal contact transmission. Methods: As part of an expert elicitation, 31 experts were asked to provide estimates of source attribution for subcategories of foodborne (n = 15), waterborne (n = 10), and animal contact (n = 3) transmission. The results from an online survey were combined using triangular probability distributions, and median and 90% credible intervals were produced. The total proportion and estimated number of cases of enteric illness attributable to each type of food commodity, water source, and animal exposure route were calculated using results from the larger elicitation survey and from a recent Canadian foodborne burden of illness study (Thomas et al., 2013). Results: Thirty experts provided foodborne subcategory estimates for 15/28 pathogens, waterborne subcategory estimates for 14/28 pathogens and animal contact subcategory estimates for 5/28. The elicitation identified raw produce, recreational water, and farm animal contact as important risk factors for enteric illness. These results also highlighted the complexity of transmission, with greater uncertainty for certain pathogens and routes of transmission. Conclusions: This study is the first of its kind to explore subcategories of foodborne, waterborne, and animal contact transmission across such a range of enteric pathogens. Despite inherent uncertainty, these estimates present an important quantitative synthesis of the roles of foodborne commodities, water sources, and pathways of animal contact in the transmission of enteric illness in Canada. PMID:26863428

  15. Estimating the Relative Role of Various Subcategories of Food, Water, and Animal Contact Transmission of 28 Enteric Diseases in Canada.

    PubMed

    Butler, Ainslie J; Pintar, Katarina D M; Thomas, M Kate

    2016-02-01

    Enteric illness represents a significant burden of illness in Canada and internationally. Building on previous research, an expert elicitation was undertaken to explore the routes of transmission for 28 pathogens involved in enteric illness in Canada. This article considers the subcategories of foodborne, waterborne, and animal contact transmission. As part of an expert elicitation, 31 experts were asked to provide estimates of source attribution for subcategories of foodborne (n = 15), waterborne (n = 10), and animal contact (n = 3) transmission. The results from an online survey were combined using triangular probability distributions, and median and 90% credible intervals were produced. The total proportion and estimated number of cases of enteric illness attributable to each type of food commodity, water source, and animal exposure route were calculated using results from the larger elicitation survey and from a recent Canadian foodborne burden of illness study (Thomas et al., 2013). Thirty experts provided foodborne subcategory estimates for 15/28 pathogens, waterborne subcategory estimates for 14/28 pathogens and animal contact subcategory estimates for 5/28. The elicitation identified raw produce, recreational water, and farm animal contact as important risk factors for enteric illness. These results also highlighted the complexity of transmission, with greater uncertainty for certain pathogens and routes of transmission. This study is the first of its kind to explore subcategories of foodborne, waterborne, and animal contact transmission across such a range of enteric pathogens. Despite inherent uncertainty, these estimates present an important quantitative synthesis of the roles of foodborne commodities, water sources, and pathways of animal contact in the transmission of enteric illness in Canada.

  16. Wettability Control of Gold Surfaces Modified with Benzenethiol Derivatives: Water Contact Angle and Thermal Stability.

    PubMed

    Tatara, Shingo; Kuzumoto, Yasutaka; Kitamura, Masatoshi

    2016-04-01

    The water wettability of Au surfaces has been controlled using various benzenethiol derivatives including 4-methylbenzenethiol, pentafluorobenzenethiol, 4-flubrobenzenethiol, 4-methoxy-benzenethiol, 4-nitrobenzenethiol, and 4-hydroxybenzenethiol. The water contact angle of the Au surface modified with the benzenethiol derivative was found to vary in the wide range of 30.9° to 88.3°. The contact angle of the modified Au films annealed was also measured in order to investigate their thermal stability. The change in the contact angle indicated that the modified surface is stable at temperatures below about 400 K. Meanwhile, the activation energy of desorption from the modified surface was estimated from the change in the contact angle. The modified Au surface was also examined using X-ray photoelectron spectroscopy.

  17. Assessment of spray application of Saint GERVAIS water effects on skin wettability by contact angle measurement comparison with bidistilled water.

    PubMed

    Elkhyat, Ahmed; Courderot-Masuyer, Carol; Mac-Mary, Sophie; Courau, Stéphanie; Gharbi, Tijani; Humbert, Philippe

    2004-11-01

    The skin is responsible for protecting the body from physical, chemical and microbial injuries. The stratum corneum is the top layer of the epidermis and it plays a key role in helping to contain moisture. When the skin becomes damaged, its ability to perform these functions is compromised. Dry skin is a common form of skin damage. Contact angle 0 between a surface and water is a good indicator of hydrophobic or hydrophilic tendency of surfaces. To quantify the influence of spray application of an isotonic mineral water (Saint GERVAIS water) on the hydrophobic tendency of dry skin and to compare spreading of both types of water on the skin through 0 measurement of each water drop on the skin before and after mineral spray application. Contact angles theta between skin surface and the two types of water (bidistilled and mineral water) were measured before and after application of mineral water by a system allowing the measurement of theta in vivo and in vitro. The cutaneous hydration, the temperature and pH were also measured before and after mineral water application. As for the application of mineral water, the cutaneous pH significantly increased so the strong skin acidity decreased. The cutaneous temperature was modified (a decrease of 2 degrees C was noted) and the cutaneous hydration was also increased (+47AU). The hydro-phobic tendency of the dry skin tested in this study was strongly decreased after mineral water application. This parameter was illustrated by a decrease of contact angle theta value. Saint GERVAIS water application allowed a regulation of skin pH, a fresh sensation on the skin and an increase in the cutaneous hydration. Moreover, the contact angle measurement with bidistilled water illustrated the increased wettability of the skin.

  18. Factors influencing health care workers' implementation of tuberculosis contact tracing in Kweneng, Botswana.

    PubMed

    Tlale, Lebapotswe; Frasso, Rosemary; Kgosiesele, Onalenna; Selemogo, Mpho; Mothei, Quirk; Habte, Dereje; Steenhoff, Andrew

    2016-01-01

    TB contact tracing rates remain low in high burden settings and reasons for this are not well known. We describe factors that influence health care workers' (HCW) implementation of TB contact tracing (CT) in a high TB burden district of Botswana. Data were collected using questionnaires and in-depth interviews in 31 of the 52 health facilities in Kweneng East Health District. Responses were summarized using summary statistics and comparisons between HCW groups were done using parametric or non-parametric tests as per normality of the data distribution. One hundred and four HCWs completed questionnaires. Factors that influenced HCW TB contact tracing were their knowledge, attitudes and practices as well as personal factors including decreased motivation and lack of commitment. Patient factors included living further away from the clinic, unknown residential address and high rates of migration and mobility. Administrative factors included staff shortages, lack of transport, poor reporting of TB cases and poor medical infrastructure e.g. suboptimal laboratory services. A national HCW strike and a restructuring of the health system emerged as additional factors during in-depth interviews of TB coordinators. Multiple factors lead to poor TB contact tracing in this district. Interventions to increase TB contact tracing will be informed by these findings.

  19. Factors influencing health care workers’ implementation of tuberculosis contact tracing in Kweneng, Botswana

    PubMed Central

    Tlale, Lebapotswe; Frasso, Rosemary; Kgosiesele, Onalenna; Selemogo, Mpho; Mothei, Quirk; Habte, Dereje; Steenhoff, Andrew

    2016-01-01

    Introduction TB contact tracing rates remain low in high burden settings and reasons for this are not well known. We describe factors that influence health care workers' (HCW) implementation of TB contact tracing (CT) in a high TB burden district of Botswana. Methods Data were collected using questionnaires and in-depth interviews in 31 of the 52 health facilities in Kweneng East Health District. Responses were summarized using summary statistics and comparisons between HCW groups were done using parametric or non-parametric tests as per normality of the data distribution. Results One hundred and four HCWs completed questionnaires. Factors that influenced HCW TB contact tracing were their knowledge, attitudes and practices as well as personal factors including decreased motivation and lack of commitment. Patient factors included living further away from the clinic, unknown residential address and high rates of migration and mobility. Administrative factors included staff shortages, lack of transport, poor reporting of TB cases and poor medical infrastructure e.g. suboptimal laboratory services. A national HCW strike and a restructuring of the health system emerged as additional factors during in-depth interviews of TB coordinators. Conclusion Multiple factors lead to poor TB contact tracing in this district. Interventions to increase TB contact tracing will be informed by these findings. PMID:27800084

  20. Thin insulating tunneling contacts for efficient and water-resistant perovskite solar cells

    DOE PAGES

    Wang, Qi; Dong, Qingfeng; Li, Tao; ...

    2016-05-17

    Here, we demonstrated that inserting a tunneling layer between perovskite and electron transport layer could significantly increase device performance by suppressing carrier recombination at the cathode contact. The tunneling layer can also serve as an encapsulation layer to prevent perovskite film from damage caused by water or moisture. This method is simple because it does not need lattice matching between the buffer layer and perovskite. The low temperature solution process makes it compatible with many types of perovskite materials, and may be applied for anode contact as well. The freedom to choose any insulating layer for contact enables more devicemore » designs and manufacturing.« less

  1. Thin insulating tunneling contacts for efficient and water-resistant perovskite solar cells

    SciTech Connect

    Wang, Qi; Dong, Qingfeng; Li, Tao; Gruverman, Alexei; Huang, Jinsong

    2016-05-17

    Here, we demonstrated that inserting a tunneling layer between perovskite and electron transport layer could significantly increase device performance by suppressing carrier recombination at the cathode contact. The tunneling layer can also serve as an encapsulation layer to prevent perovskite film from damage caused by water or moisture. This method is simple because it does not need lattice matching between the buffer layer and perovskite. The low temperature solution process makes it compatible with many types of perovskite materials, and may be applied for anode contact as well. The freedom to choose any insulating layer for contact enables more device designs and manufacturing.

  2. Thin insulating tunneling contacts for efficient and water-resistant perovskite solar cells

    SciTech Connect

    Wang, Qi; Dong, Qingfeng; Li, Tao; Gruverman, Alexei; Huang, Jinsong

    2016-05-17

    Here, we demonstrated that inserting a tunneling layer between perovskite and electron transport layer could significantly increase device performance by suppressing carrier recombination at the cathode contact. The tunneling layer can also serve as an encapsulation layer to prevent perovskite film from damage caused by water or moisture. This method is simple because it does not need lattice matching between the buffer layer and perovskite. The low temperature solution process makes it compatible with many types of perovskite materials, and may be applied for anode contact as well. The freedom to choose any insulating layer for contact enables more device designs and manufacturing.

  3. A review of factors that affect contact angle and implications for flotation practice.

    PubMed

    Chau, T T; Bruckard, W J; Koh, P T L; Nguyen, A V

    2009-09-30

    Contact angle and the wetting behaviour of solid particles are influenced by many physical and chemical factors such as surface roughness and heterogeneity as well as particle shape and size. A significant amount of effort has been invested in order to probe the correlation between these factors and surface wettability. Some of the key investigations reported in the literature are reviewed here. It is clear from the papers reviewed that, depending on many experimental conditions such as the size of the surface heterogeneities and asperities, surface cleanliness, and the resolution of measuring equipment and data interpretation, obtaining meaningful contact angle values is extremely difficult and such values are reliant on careful experimental control. Surface wetting behaviour depends on not only surface texture (roughness and particle shape), and surface chemistry (heterogeneity) but also on hydrodynamic conditions in the preparation route. The inability to distinguish the effects of each factor may be due to the interplay and/or overlap of two or more factors in each system. From this review, it was concluded that: Surface geometry (and surface roughness of different scales) can be used to tune the contact angle; with increasing surface roughness the apparent contact angle decreases for hydrophilic materials and increases for hydrophobic materials. For non-ideal surfaces, such as mineral surfaces in the flotation process, kinetics plays a more important role than thermodynamics in dictating wettability. Particle size encountered in flotation (10-200 microm) showed no significant effect on contact angle but has a strong effect on flotation rate constant. There is a lack of a rigid quantitative correlation between factors affecting wetting, wetting behaviour and contact angle on minerals; and hence their implication for flotation process. Specifically, universal correlation of contact angle to flotation recovery is still difficult to predict from first principles

  4. Effect of capillary-condensed water on the dynamic friction force at nanoasperity contacts

    NASA Astrophysics Data System (ADS)

    Sirghi, L.

    2003-05-01

    A single nanoasperity contact in ambient air is usually wetted by capillary condensation of water vapor and is surrounded by a water meniscus. This phenomenon strongly affects the contact friction, not only by the effect of meniscus loading force (superficial tension and capillary forces), but also by a friction force that accounts for the energy loss in the meniscus movement along with the sliding contact. Occurrence of the water-meniscus-generated friction is experimentally proved by atomic force microscopy measurements of the tip-sample friction force at minimum possible external load (before pull-off). A qualitative explanation for the observed dependence of the friction force on air humidity and solid surface wettability is proposed.

  5. Involvement of the transcription factor FoxM1 in contact inhibition

    SciTech Connect

    Faust, Dagmar; Al-Butmeh, Firas; Linz, Berenike; Dietrich, Cornelia

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer The transcription factor FoxM1 is downregulated upon contact inhibition. Black-Right-Pointing-Pointer The decrease in FoxM1 levels occurs very likely due to inhibition of ERK activity. Black-Right-Pointing-Pointer The decrease in FoxM1 is not sufficient, but required for contact inhibition. Black-Right-Pointing-Pointer We propose a new model of contact inhibition involving pRB/E2F and FoxM1. -- Abstract: Contact inhibition is a crucial mechanism regulating proliferation in vitro and in vivo. Although it is generally accepted that contact inhibition plays a pivotal role in maintaining tissue homeostasis, the molecular mechanisms of contact inhibition are still not fully understood. FoxM1 is known as a proliferation-associated transcription factor and is upregulated in many cancer types. Vice versa, anti-proliferative signals, such as TGF-{beta} and differentiation signals decrease FoxM1 expression. Here we investigated the role of FoxM1 in contact inhibition in fibroblasts. We show that protein expression of FoxM1 is severely and rapidly downregulated upon contact inhibition, probably by inhibition of ERK activity, which then leads to decreased expression of cyclin A and polo-like kinase 1. Vice versa, ectopic expression of FoxM1 prevents the decrease in cyclin A and polo-like kinase 1 and causes a two-fold increase in saturation density indicating loss of contact inhibition. Hence, we show that downregulation of FoxM1 is required for contact inhibition by regulating expression of cyclin A and polo-like kinase 1.

  6. US FDA's revised consumption factor for polystyrene used in food-contact applications.

    PubMed

    Cassidy, K; Elyashiv-Barad, S

    2007-09-01

    US FDA's continual effort to evaluate the safety of food-contact materials includes periodically re-examining our established packaging factors, such as consumption and food-type distribution factors. The use of polystyrene in food-contact and disposable food-packaging applications has expanded and is expected to continue to increase in the future. Therefore, it is important to revise the polystyrene consumption factor to account for increases in consumer exposure to substances migrating from styrenic food packaging. The currently used consumption factor for polystyrene is 0.1, which is based on market data collected around 1980. US FDA has revised the polystyrene consumption factor utilizing three different sources of market data. Using consumption and population data, US FDA calculated a new consumption factor of 0.14 for polystyrene. This consumption factor has been further subdivided to allow for the refinement of exposure estimates for uses limited to specific subcategories of polystyrene packaging.

  7. Layered Double Hydroxide Nanoplatelets with Excellent Tribological Properties under High Contact Pressure as Water-Based Lubricant Additives

    NASA Astrophysics Data System (ADS)

    Wang, Hongdong; Liu, Yuhong; Chen, Zhe; Wu, Bibo; Xu, Sailong; Luo, Jianbin

    2016-03-01

    High efficient and sustainable utilization of water-based lubricant is essential for saving energy. In this paper, a kind of layered double hydroxide (LDH) nanoplatelets is synthesized and well dispersed in water due to the surface modification with oleylamine. The excellent tribological properties of the oleylamine-modified Ni-Al LDH (NiAl-LDH/OAm) nanoplatelets as water-based lubricant additives are evaluated by the tribological tests in an aqueous environment. The modified LDH nanoplatelets are found to not only reduce the friction but also enhance the wear resistance, compared with the water-based cutting fluid and lubricants containing other particle additives. By adding 0.5 wt% LDH nanoplatelets, under 1.5 GPa initial contact pressure, the friction coefficient, scar diameter, depth and width of the wear track dramatically decrease by 83.1%, 43.2%, 88.5% and 59.5%, respectively. It is considered that the sufficiently small size and the excellent dispersion of NiAl-LDH/OAm nanoplatelets in water are the key factors, so as to make them enter the contact area, form a lubricating film and prevent direct collision of asperity peaks. Our investigations demonstrate that the LDH nanoplatelet as a water-based lubricant additive has a great potential value in industrial application.

  8. Layered Double Hydroxide Nanoplatelets with Excellent Tribological Properties under High Contact Pressure as Water-Based Lubricant Additives

    PubMed Central

    Wang, Hongdong; Liu, Yuhong; Chen, Zhe; Wu, Bibo; Xu, Sailong; Luo, Jianbin

    2016-01-01

    High efficient and sustainable utilization of water-based lubricant is essential for saving energy. In this paper, a kind of layered double hydroxide (LDH) nanoplatelets is synthesized and well dispersed in water due to the surface modification with oleylamine. The excellent tribological properties of the oleylamine-modified Ni-Al LDH (NiAl-LDH/OAm) nanoplatelets as water-based lubricant additives are evaluated by the tribological tests in an aqueous environment. The modified LDH nanoplatelets are found to not only reduce the friction but also enhance the wear resistance, compared with the water-based cutting fluid and lubricants containing other particle additives. By adding 0.5 wt% LDH nanoplatelets, under 1.5 GPa initial contact pressure, the friction coefficient, scar diameter, depth and width of the wear track dramatically decrease by 83.1%, 43.2%, 88.5% and 59.5%, respectively. It is considered that the sufficiently small size and the excellent dispersion of NiAl-LDH/OAm nanoplatelets in water are the key factors, so as to make them enter the contact area, form a lubricating film and prevent direct collision of asperity peaks. Our investigations demonstrate that the LDH nanoplatelet as a water-based lubricant additive has a great potential value in industrial application. PMID:26951794

  9. Apparent Contact Angle Calculated from a Water Repellent Model with Pinning Effect.

    PubMed

    Suzuki, Shojiro; Ueno, Kazuyuki

    2017-01-10

    A set of new theoretical equations for apparent contact angles is proposed. The equations are derived from an equilibrium of interfacial tensions of a three-phase contact line pinned at the edges of a fine structure. These equations are validated by comparison with contact-angle measurement results for 2 μL water droplets on poly(methyl methacrylate) microstructured samples with square pillars or holes. The equilibrium contact angles predicted by the new equations reasonably agree with the experimental results. In contrast, the values predicted by the Cassie-Baxter equation or the Wenzel equation do not qualitatively agree with the experimental results in pillar pattern cases because the Cassie-Baxter equation and the Wenzel equation do not account for the pinning effect.

  10. Steady-State Diffusion of Water through Soft-Contact LensMaterials

    SciTech Connect

    Fornasiero, Francesco; Krull, Florian; Radke, Clayton J.; Prausnitz, JohnM.

    2005-01-31

    Water transport through soft contact lenses (SCL) is important for acceptable performance on the human eye. Chemical-potential gradient-driven diffusion rates of water through soft-contact-lens materials are measured with an evaporation-cell technique. Water is evaporated from the bottom surface of a lens membrane by impinging air at controlled flow rate and humidity. The resulting weight loss of a water reservoir covering the top surface of the contact-lens material is recorded as a function of time. New results are reported for a conventional hydrogel material (SofLens{trademark} One Day, hilafilcon A, water content at saturation W{sub 10} = 70 weight %) and a silicone hydrogel material (PureVision{trademark}, balafilcon A, W{sub 10} = 36 %), with and without surface oxygen plasma treatment. Also, previously reported data for a conventional HEMA-SCL (W{sub 10} = 38 %) hydrogel are reexamined and compared with those for SofLens{trademark} One Day and PureVision{trademark} hydrogels. Measured steady-state water fluxes are largest for SofLens{trademark} One Day, followed by PureVision{trademark} and HEMA. In some cases, the measured steady-state water fluxes increase with rising relative air humidity. This increase, due to an apparent mass-transfer resistance at the surface (trapping skinning), is associated with formation of a glassy skin at the air/membrane interface when the relative humidity is below 55-75%. Steady-state water-fluxes are interpreted through an extended Maxwell-Stefan diffusion model for a mixture of species starkly different in size. Thermodynamic nonideality is considered through Flory-Rehner polymer-solution theory. Shrinking/swelling is self-consistently modeled by conservation of the total polymer mass. Fitted Maxwell-Stefan diffusivities increase significantly with water concentration in the contact lens.

  11. Water Contact Angle Dependence with Hydroxyl Functional Groups on Silica Surfaces under CO2 Sequestration Conditions.

    PubMed

    Chen, Cong; Zhang, Ning; Li, Weizhong; Song, Yongchen

    2015-12-15

    Functional groups on silica surfaces under CO2 sequestration conditions are complex due to reactions among supercritical CO2, brine and silica. Molecular dynamics simulations have been performed to investigate the effects of hydroxyl functional groups on wettability. It has been found that wettability shows a strong dependence on functional groups on silica surfaces: silanol number density, space distribution, and deprotonation/protonation degree. For neutral silica surfaces with crystalline structure (Q(3), Q(3)/Q(4), Q(4)), as silanol number density decreases, contact angle increases from 33.5° to 146.7° at 10.5 MPa and 318 K. When Q(3) surface changes to an amorphous structure, water contact angle increases 20°. Water contact angle decreases about 12° when 9% of silanol groups on Q(3) surface are deprotonated. When the deprotonation degree increases to 50%, water contact angle decreases to 0. The dependence of wettability on silica surface functional groups was used to analyze contact angle measurement ambiguity in literature. The composition of silica surfaces is complicated under CO2 sequestration conditions, the results found in this study may help to better understand wettability of CO2/brine/silica system.

  12. Wetting and scanning force microscopy on rough polymer surfaces: Wenzel's roughness factor and the thermodynamic contact angle

    NASA Astrophysics Data System (ADS)

    Kamusewitz, H.; Possart, W.

    The influence of the surface roughness of polypropylene on the contact angle hysteresis is investigated by means of ethylene glycol drops in order to estimate the true Young's equilibrium contact angle. A new relationship between the contact angle hysteresis and Wenzel's contact angle is derived. In addition, the determination of Wenzel's roughness factor by means of scanning force microscopy opens an alternative way to obtaining Young's equilibrium contact angle without any surface manipulation. The experimental results presented verify this new approach.

  13. Imaging of oil layers, curvature and contact angle in a mixed-wet and a water-wet carbonate rock

    NASA Astrophysics Data System (ADS)

    Singh, Kamaljit; Bijeljic, Branko; Blunt, Martin J.

    2016-03-01

    We have investigated the effect of wettability of carbonate rocks on the morphologies of remaining oil after sequential oil and brine injection in a capillary-dominated flow regime at elevated pressure. The wettability of Ketton limestone was altered in situ using an oil phase doped with fatty acid which produced mixed-wet conditions (the contact angle where oil contacted the solid surface, measured directly from the images, θ=180°, while brine-filled regions remained water-wet), whereas the untreated rock (without doped oil) was weakly water-wet (θ=47 ± 9°). Using X-ray micro-tomography, we show that the brine displaces oil in larger pores during brine injection in the mixed-wet system, leaving oil layers in the pore corners or sandwiched between two brine interfaces. These oil layers, with an average thickness of 47 ± 17 µm, may provide a conductive flow path for slow oil drainage. In contrast, the oil fragments into isolated oil clusters/ganglia during brine injection under water-wet conditions. Although the remaining oil saturation in a water-wet system is about a factor of two larger than that obtained in the mixed-wet rock, the measured brine-oil interfacial area of the disconnected ganglia is a factor of three smaller than that of oil layers.

  14. Risk factors for contact lens-related microbial keratitis in Singapore

    PubMed Central

    Lim, C H L; Carnt, N A; Farook, M; Lam, J; Tan, D T; Mehta, J S; Stapleton, F

    2016-01-01

    Purpose: To investigate independent risk factors for contact lens-related microbial keratitis in Singapore and estimate their impact on disease load. Methods: Cases were contact lens wearers presenting to Singapore National Eye Centre with microbial keratitis between 2008 and 2010. Community contact lens wearers were recruited as controls. All wearers completed a previously validated questionnaire describing contact lens wear history, hygiene and compliance habits, and demographics. Risk factors significant in univariate analysis (P<0.2) were evaluated in a multivariate model. Results: In all, 58 cases of microbial keratitis and 152 contemporaneous controls were identified. When controlling for other variables, Chinese had a 7 × lower risk compared with other races (95% CI: 2.3–21.3, P=0.001). Those aged between 25 and 44 years were at 3 × increased risk compared with younger wearers (95% CI: 1.1–9.6, P=0.04). Occasional overnight contact lens wear (less often than one night per week) was associated with a 4 × higher risk (95% CI: 1.2–15.4, P=0.03) compared with daily use. Not washing hands before handling was associated with a 13 × increased risk (95% CI: 1.9–84.8, P=0.008). Use of multipurpose solution A carried a 16 × higher risk compared with hydrogen peroxide (95% CI: 1.5–174.0, P=0.02). The combined PAR% for modifiable risk factors (occasional overnight wear, not washing of hands, and MPS A) was 82%. Conclusions: Consistent with previous findings, independent risk factors for contact lens-related microbial keratitis include poor hand hygiene, occasional overnight wear, and type of lens care solution. Prolonged overnight or extended contact lens use was infrequent in this population. PMID:26634710

  15. Barriers to Predicting the Mechanisms and Risk Factors of Non-Contact Anterior Cruciate Ligament Injury

    PubMed Central

    Ali, Nicholas; Rouhi, Gholamreza

    2010-01-01

    High incidences of non-contact anterior cruciate ligament (ACL) injury, frequent requirements for ACL reconstruction, and limited understanding of ACL mechanics have engendered considerable interest in quantifying the ACL loading mechanisms. Although some progress has been made to better understand non-contact ACL injuries, information on how and why non-contact ACL injuries occur is still largely unavailable. In other words, research is yet to yield consensus on injury mechanisms and risk factors. Biomechanics, video analysis, and related study approaches have elucidated to some extent how ACL injuries occur. However, these approaches are limited because they provide estimates, rather than precise measurements of knee - and more specifically ACL - kinematics at the time of injury. These study approaches are also limited in their inability to simultaneously capture many of the contributing factors to injury. This paper aims at elucidating and summarizing the key challenges that confound our understanding in predicting the mechanisms and subsequently identifying risk factors of non-contact ACL injury. This work also appraise the methodological rigor of existing study approaches, review testing protocols employed in published studies, as well as presents a possible coupled approach to better understand injury mechanisms and risk factors of non-contact ACL injury. Three comprehensive electronic databases and hand search of journal papers, covering numerous full text published English articles were utilized to find studies on the association between ACL and injury mechanisms, ACL and risk factors, as well as, ACL and investigative approaches. This review unveils that new research modalities and/or coupled research methods are required to better understand how and why the ACL gets injured. Only by achieving a better understanding of ACL loading mechanisms and the associated contributing factors, one will be able to develop robust prevention strategies and exercise

  16. Contact angle assessment of hydrophobic silica nanoparticles related to the mechanisms of dry water formation.

    PubMed

    Forny, Laurent; Saleh, Khashayar; Denoyel, Renaud; Pezron, Isabelle

    2010-02-16

    Dry water is a very convenient way of encapsulating a high amount of aqueous solutions in a powder form made of hydrophobic silica nanoparticles. It was demonstrated in previous studies that both solid and liquid interfacial properties influence the quality of the final product resulting occasionally in mousse formation. To explain this behavior, contact angles of silica nanoparticles have been measured for water and water/ethanol solution by means of liquid intrusion experiments. It was found that the quality of the final product correlates with the contact angle, i.e., contact angle close to 105 degrees leads to mousse formation whereas a slightly higher value of approximately 118 degrees allows dry water formation. The proposed explanation was based on the energy of immersion and adhesion defined as the energy needed for a spherical particle to respectively penetrate into the liquid or attach at the liquid/air interface. Significantly lower energy of immersion calculated for lower contact angle might account for particle penetration into the liquid phase during processing, leading to continuous network aggregation, air entrapment, and finally mousse formation.

  17. Non-contact measurements of water jet spreading width with a laser instrument

    NASA Astrophysics Data System (ADS)

    Funami, Yuki; Hasuya, Ryo; Tanabe, Kotaro; Nakanishi, Yuji

    2016-08-01

    Jet spreading width is one of the important characteristics of water jets discharging into the air. Many researchers have dealt with measuring this width, and contact measuring methods on the water jet surface were employed in a lot of the cases. In order to avoid undesirable effects caused by the contact on the jet surface, we introduce non-contact measuring methods with a laser instrument to the measurements of jet spreading width. In measurements, a transmitter emits sheet-like laser beam to a receiver. The water jet between the transmitter and the receiver interrupts the laser beam and makes a shadow. The minimum and maximum values of the shadow width are measured. In addition, pictures of the water jet are taken with a scale, and the shadow width is measured from the pictures. The experiments on various needle strokes were performed. Three kinds of width consistent with the jet structure were obtained. In the results, it can be concluded that our non-contact measuring methods are feasible. The data of jet spreading widths and jet taper were obtained and are useful for future applications.

  18. Influence of temperature and pressure on quartz-water-CO₂ contact angle and CO₂-water interfacial tension.

    PubMed

    Sarmadivaleh, Mohammad; Al-Yaseri, Ahmed Z; Iglauer, Stefan

    2015-03-01

    We measured water-CO2 contact angles on a smooth quartz surface (RMS surface roughness ∼40 nm) as a function of pressure and temperature. The advancing water contact angle θ was 0° at 0.1 MPa CO2 pressure and all temperatures tested (296-343 K); θ increased significantly with increasing pressure and temperature (θ=35° at 296 K and θ=56° at 343 K at 20 MPa). A larger θ implies less structural and residual trapping and thus lower CO2 storage capacities at higher pressures and temperatures. Furthermore we did not identify any significant influence of CO2-water equilibration on θ. Moreover, we measured the CO2-water interfacial tension γ and found that γ strongly decreased with increasing pressure up to ∼10 MPa, and then decreased with a smaller slope with further increasing pressure. γ also increased with increasing temperature.

  19. Elimination of undesirable water layers in solid contact polymeric ion-selective electrodes

    PubMed Central

    Veder, Jean-Pierre; De Marco, Roland; Clarke, Graeme; Chester, Ryan; Nelson, Andrew; Prince, Kathryn; Pretsch, Ernö; Bakker, Eric

    2008-01-01

    This study aims to develop a novel approach for the production of analytically robust and miniaturized polymeric ion sensors that are vitally important in modern analytical chemistry (e.g., clinical chemistry using single blood droplets, modern biosensors measuring clouds of ions released from nanoparticle tagged biomolecules, lab-on-a-chip applications, etc.). This research has shown that the use of a water repellent polymethyl methacrylate/polydecyl methacrylate (PMMA/PDMA) copolymer as the ion sensing membrane, along with a hydrophobic poly(3-octylthiophene 2,5-diyl) (POT) solid-contact as the ion-to-electron transducer, is an excellent strategy for avoiding the detrimental water layer formed at the buried interface of solid-contact ISEs. Accordingly, it has been necessary to implement a rigorous surface analysis scheme employing electrochemical impedance spectroscopy (EIS), in-situ neutron reflectometry/EIS (NR/EIS), secondary ion mass spectrometry (SIMS) and small angle neutron scattering (SANS) to probe structurally the solid-contact/membrane interface, so as to identify the conditions that eliminate the undesirable water layer in all solid-state polymeric ion sensors. In this work, we provide the first experimental evidence that the PMMA/PDMA copolymer system is susceptible to water “pooling” at the interface in areas surrounding physical imperfections in the solid-contact, with the exposure time for such an event in a PMMA/PDMA copolymer ISE taking nearly twenty times longer than that for a plasticized polyvinyl chloride (PVC) ISE, and the simultaneous use of a hydrophobic POT solid-contact with a PMMA/PDMA membrane can eliminate totally this water layer problem. PMID:18671410

  20. Elimination of undesirable water layers in solid-contact polymeric ion-selective electrodes.

    PubMed

    Veder, Jean-Pierre; De Marco, Roland; Clarke, Graeme; Chester, Ryan; Nelson, Andrew; Prince, Kathryn; Pretsch, Ernö; Bakker, Eric

    2008-09-01

    This study aimed to develop a novel approach for the production of analytically robust and miniaturized polymeric ion sensors that are vitally important in modern analytical chemistry (e.g., clinical chemistry using single blood droplets, modern biosensors measuring clouds of ions released from nanoparticle-tagged biomolecules, laboratory-on-a-chip applications, etc.). This research has shown that the use of a water-repellent poly(methyl methacrylate)/poly(decyl methacrylate) (PMMA/PDMA) copolymer as the ion-sensing membrane, along with a hydrophobic poly(3-octylthiophene 2,5-diyl) (POT) solid contact as the ion-to-electron transducer, is an excellent strategy for avoiding the detrimental water layer formed at the buried interface of solid-contact ion-selective electrodes (ISEs). Accordingly, it has been necessary to implement a rigorous surface analysis scheme employing electrochemical impedance spectroscopy (EIS), in situ neutron reflectometry/EIS (NR/EIS), secondary ion mass spectrometry (SIMS), and small-angle neutron scattering (SANS) to probe structurally the solid-contact/membrane interface, so as to identify the conditions that eliminate the undesirable water layer in all solid-state polymeric ion sensors. In this work, we provide the first experimental evidence that the PMMA/PDMA copolymer system is susceptible to water "pooling" at the interface in areas surrounding physical imperfections in the solid contact, with the exposure time for such an event in a PMMA/PDMA copolymer ISE taking nearly 20 times longer than that for a plasticized poly(vinyl chloride) (PVC) ISE, and the simultaneous use of a hydrophobic POT solid contact with a PMMA/PDMA membrane can eliminate totally this water layer problem.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. The reaction on a float bottom when making contact with water at high speeds

    NASA Technical Reports Server (NTRS)

    Richardson, H C

    1928-01-01

    Tests were conducted to investigate the possibility of a serious accident arising from unintentional contact with the water in substantially horizontal flight at high speed. Referring to vector diagrams on Figure 2, it will be seen that a very dangerous condition may arise if the float be allowed to come in contact with the water at high speeds as, for example, when flying at high speed just above the water. The initial diving moment due to suction and drag combined may be great enough to cause the seaplane to nose under before the pilot is able to control the motion. The same test data indicate clearly the existence of forces and moments tending to produce the phenomenon observed by Mr. Carroll (Technical Note No. 287) when the maneuver is carried out at lower speeds, as in a landing.

  3. Oxygen, water, and sodium chloride transport in soft contact lenses materials.

    PubMed

    Gavara, Rafael; Compañ, Vicente

    2017-11-01

    Oxygen permeability, diffusion coefficient of the sodium ions and water flux and permeability in different conventional hydrogel (Hy) and silicone-hydrogel (Si-Hy) contact lenses have been measured experimentally. The results showed that oxygen permeability and transmissibility requirements of the lens have been addressed through the use of siloxane containing hydrogels. In general, oxygen and sodium chloride permeability values increased with the water content of the lens but there was a percolation phenomenon from a given value of water uptake mainly in the Si-Hy lenses which appeared to be related with the differences between free water and bound water contents. The increase of ion permeability with water content did not follow a unique trend indicating a possible dependence of the chemical structure of the polymer and character ionic and non-ionic of the lens. Indeed, the salt permeability values for silicone hydrogel contact lenses were one order of magnitude below those of conventional hydrogel contact lenses, which can be explained by a diffusion of sodium ions occurring only through the hydrophilic channels. The increase of the ionic permeability in Si-Hy materials may be due to the confinement of ions in nanoscale water channels involving possible decreased degrees of freedom for diffusion of both water and ions. In general, ionic lenses presented values of ionic permeability and diffusivity higher than most non-ionic lenses. The tortuosity of the ionic lenses is lower than the non-ionic Si-Hy lenses. Frequency 55 and PureVision exhibited the highest water permeability and flux values and, these parameters were greater for ionic Si-Hy lenses than for ionic conventional hydrogel lenses. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2218-2231, 2017. © 2016 Wiley Periodicals, Inc.

  4. Steady-state diffusion of water through soft-contact-lens materials.

    PubMed

    Fornasiero, Francesco; Krull, Florian; Prausnitz, John M; Radke, Clayton J

    2005-10-01

    Water transport through soft contact lenses (SCL) is important for acceptable performance on the human eye. Chemical-potential gradient-driven diffusion rates of water through SCL materials are measured with an evaporation-cell technique. Water is evaporated from the bottom surface of a lens membrane by impinging air at controlled flow rate and humidity. The resulting weight loss of a water reservoir covering the top surface of the contact-lens material is recorded as a function of time. New results are reported for a conventional hydrogel material (SofLens One Day, hilafilcon A, water content at saturation w10 = 70 weight %) and a silicone hydrogel material (PureVision, balafilcon A, w10 = 36%), with and without surface oxygen plasma treatment. Also, previously reported data for a conventional 2-hydroxyethyl methacrylate (HEMA)-SCL (w10 = 38%) hydrogel are reexamined and compared with those for SofLens One Day and PureVision hydrogels. Measured steady-state water fluxes are largest for SofLens One Day, followed by PureVision and HEMA. In some cases, the measured steady-state water fluxes increase with rising relative air humidity. This increase, due to an apparent mass-transfer resistance at the surface (trapping skinning), is associated with formation of a glassy skin at the air/membrane interface when the relative humidity is below 55-75%. Steady-state water fluxes are interpreted through an extended Maxwell-Stefan diffusion model for a mixture of species starkly different in size. Thermodynamic nonideality is considered through Flory-Rehner polymer-solution theory. Shrinking/swelling is self-consistently modeled by conservation of the total polymer mass. Fitted Maxwell-Stefan diffusivities increase significantly with water concentration in the contact lens.

  5. Dehumidification of Moist Air by Direct Contact Heat and Mass Transfer in Cold Water Solution

    NASA Astrophysics Data System (ADS)

    Inaba, Hideo; Horibe, Akihiko; Haruki, Naoto; Ishioka, Tohru; Takeuchi, Yoshiyuki

    This paper has dealt with the direct contact heat and mass transfer characteristics of dehumidification of flowing moist air bubbles in a cold water solution (propylene glycoI). The saturated water-vapor humidity of propylene glycol water solution was measured under some conditions of temperature and mass concentration of the water solution. Experiments on dehumidification of air bubbles were performed by ascending air bubbles in the water absorbing solution for various parameters of air temperature, humidity and flow rate etc. The experimental data of air bubble diameter, dehumidification rate and apparent heat transfer coefficient were correlated by means of some experimental parameters such as air temperature, humidity, flow rate and height of water solution layer.

  6. Water-mediated contacts in the trp-repressor operator complex recognition process.

    PubMed

    Wibowo, Fajar R; Rauch, Christine; Trieb, Michael; Wellenzohn, Bernd; Liedl, Klaus R

    2004-04-15

    Water-mediated contacts are known as an important recognition tool in trp-repressor operator systems. One of these contacts involves two conserved base pairs (G(6).C(-6) and A(5). T(-5)) and three amino acids (Lys 72, Ile 79, and Ala 80). To investigate the nature of these contacts, we analyzed the X-ray structure (PDB code: 1TRO) of the trp-repressor operator complex by means of molecular dynamics simulations. This X-ray structure contains two dimers that exhibit structural differences. From these two different starting structures, two 10 ns molecular dynamics simulations have been performed. Both of our simulations show an increase of water molecules in the major groove at one side of the dimer, while the other side remains unchanged compared to the X-ray structure. Though the maximum residence time of the concerned water molecules decreases with an increase of solvent at the interface, these water molecules continue to play an important role in mediating DNA-protein contacts. This is shown by new stable amino acids-DNA distances and a long water residence time compared to free DNA simulation. To maintain stability of the new contacts, the preferential water binding site on O6(G6) is extended. This extension agrees with mutation experiment data on A5 and G6, which shows different relative affinity due to mutation on these bases [A. Joachimiak, T. E. Haran, P. B. Sigler, EMBO Journal 1994, Vol. 13, No. (2) pp. 367-372]. Due to the rearrangements in the system, the phosphate of the base G6 is able to interconvert to the B(II) substate, which is not observed on the other half side of the complex. The decrease of the number of hydrogen bonds between protein and DNA backbone could be the initial step of the dissociation process of the complex, or in other words an intermediate complex conformation of the association process. Thus, we surmise that these features show the importance of water-mediated contacts in the trp-repressor operator recognition process.

  7. A hitherto undescribed plasma factor acting at the contact phase of blood coagulation (Flaujeac factor): case report and coagulation studies.

    PubMed

    Lacombe, M J; Varet, B; Levy, J P

    1975-11-01

    This paper reports an asymptomatic coagulation defect responsible for an abnormality at the contact phase of blood coagulation in vitro, distinct from Hageman factor and Fletcher factor deficiencies. Coagulation studies in a 50-yr-old French woman without bleeding tendency revealed the following results: whole-blood clotting time in glass tubes and activated partial thromboplastin time with kaolin and ellagic acid were greatly prolonged; one-stage prothrombin was normal; no circulating anticoagulant was detected, and the infusion of normal plasma corrected the coagulation defect with an estimated half-life of 6.5 days; the levels of factor VIII, IX, XI, and XII were normal; mutual correction was obtained with a Fletcher factor-deficient plasma; the level of whole complement was normal. Studies of the contact phase of blood coagulation and contact-induced fibrinolysis showed the same abnormalities as in Hageman factor- and Fletcher-deficient plasmas. These results indicate that the patient's plasma is deficient in a previously undescribed coagulation factor, which participates in the initial stage of the blood coagulation process in vitro. Family studies revealed consanguinity in the propositus' parents. The assay of this newly described factor in the propositus' children revealed a partial defect, compatible with a heterozygous state, in three of the four tested children. This indicates a recessive inheritance of this new blood coagulation defect.

  8. Do cool water or physiologic saline compresses enhance resolution of experimentally-induced irritant contact dermatitis?

    PubMed

    Levin, C Y; Maibach, H I

    2001-09-01

    Acute irritant contact dermatitis (ICD) is frequently treated with cool water or saline compresses. While presumed effective, little quantitative evaluation documents the treatment's benefit. This study sought to determine the efficacy of both distilled water and physiologic saline compresses on experimentally-induced ICD. 24-h application of both the lipophilic nonanoic acid (NAA) and the hydrophilic sodium lauryl sulfate (SLS) were used to induce irritant contact dermatitis in 9 healthy volunteers. Following irritation, compresses were applied 0.5 h 2x daily for 4 consecutive days. Transepidermal water loss (TEWL), laser Doppler flowmetry (LDF), chromametry and visual scoring were used to quantify results. Cool compresses of both water and saline significantly reduced TEWL and LDF, with no statistically significant difference between the efficacy of the saline or water compresses. Chromametry and visual scoring did not detect a significant effect with either the water or saline compresses. The results suggest an improvement with 2x-daily application of either water or physiologic saline compresses in the treatment of acute ICD, though true clinical benefit will be elucidated through further experimentation. Certainly, the current recommendation regarding the use of cool compresses for treating ICD should not be discarded.

  9. Visualization of the contact line during the water exit of flat plates

    NASA Astrophysics Data System (ADS)

    Tassin, A.; Breton, T.; Forest, B.; Ohana, J.; Chalony, S.; Le Roux, D.; Tancray, A.

    2017-08-01

    We investigate experimentally the time evolution of the wetted surface during the lifting of a body initially floating at the water surface. This phenomenon is referred to as the water exit problem. The water exit experiments were conducted with transparent (PMMA) mock-ups of two different shapes: a circular disc and a square flat plate. Two different lighting systems were used to diffuse light in the mock-up material: a central high-power LED light normal to the surface and an edge-lighting system featuring an array of LED lights. These setups make it possible to illuminate the contact line, which delimits the surface of contact between the mock-up and the water. The characteristic size of the mock-ups is about 20 cm and the acceleration of the mock-up oscillates between 0 and 25 m/s^2. We show that the central light setup gives satisfactory results for the circular disc and that the edge lighting technique makes it possible to follow a contact line with a time-evolving complex shape (strong changes of convexity) up to 1000 fps. The observations presented in the paper support the possibility of extending this promising technique to more general three-dimensional bodies with arbitrary motion (e.g., including pitch motion).

  10. Characterization of the Intrinsic Water Wettability of Graphite Using Contact Angle Measurements: Effect of Defects on Static and Dynamic Contact Angles.

    PubMed

    Kozbial, Andrew; Trouba, Charlie; Liu, Haitao; Li, Lei

    2017-01-31

    Elucidating the intrinsic water wettability of the graphitic surface has increasingly attracted research interests, triggered by the recent finding that the well-established hydrophobicity of graphitic surfaces actually results from airborne hydrocarbon contamination. Currently, static water contact angle (WCA) is often used to characterize the intrinsic water wettability of graphitic surfaces. In the current paper, we show that because of the existence of defects, static WCA does not necessarily characterize the intrinsic water wettability. Freshly exfoliated graphite of varying qualities, characterized using atomic force microscopy and Raman spectroscopy, was studied using static, advancing, and receding WCA measurements. The results showed that graphite of different qualities (i.e., defect density) always has a similar advancing WCA, but it could have very different static and receding WCAs. This finding indicates that defects play an important role in contact angle measurements, and the static contact angle does not always represent the intrinsic water wettability of pristine graphite. On the basis of the experimental results, a qualitative model is proposed to explain the effect of defects on static, advancing, and receding contact angles. The model suggests that the advancing WCA reflects the intrinsic water wettability of pristine (defect-free) graphite. Our results showed that the advancing WCA for pristine graphite is 68.6°, which indicates that graphitic carbon is intrinsically mildly hydrophilic.

  11. Risk Factors for Non-Contact Injury in Adolescent Cricket Pace Bowlers: A Systematic Review.

    PubMed

    Forrest, Mitchell R L; Hebert, Jeffrey J; Scott, Brendan R; Brini, Stefano; Dempsey, Alasdair R

    2017-09-06

    Adolescent cricket pace bowlers are prone to injury. Recognising the risk factors for non-contact injury in this population will aid future injury prevention strategies. To identify the risk factors for non-contact injury in adolescent cricket pace bowlers. We systematically searched PubMed, Cochrane Library, PEDro, SPORTDiscus, Embase, and the South African Journal of Sports Medicine to identify all experimental and observational studies reporting risk factors for non-contact injuries in pace bowlers (aged 12-19 years). The search syntax included terms relevant to cricket bowling, injury, and known risk factors for injury. The Newcastle-Ottawa Quality Assessment Scale and a modified Newcastle-Ottawa Quality Assessment Scale were used to assess the risk of bias in the cohort and cross-sectional studies, respectively. Sixteen studies (five cross-sectional studies, 11 cohort studies) comprising 687 participants (96% male, 75% playing cricket in Australia) met the selection criteria and were included for qualitative synthesis. Three cross-sectional studies were rated as high risk of bias and two as very high risk of bias. For the cohort studies, three were rated as low risk of bias, and eight as high risk of bias. Injury was associated with bowling biomechanics (excessive lateral trunk flexion and pelvis/hip kinematics), reduced trunk endurance, poor lumbo-pelvic-hip movement control, and early signs of lumbar bone stress. Conflicting results were found by studies examining the mixed technique, bowling workload and quadratus lumborum asymmetry. The current systematic review identified a number bowling biomechanics and various neuromuscular deficiencies as risk factors for non-contact injury in adolescent pace bowlers. These factors may provide a useful target for future interventional research aiming to prevent injury in this population. Future studies should utilise prospective cohort designs, and ensure that participants are injury-free at baseline, confounding

  12. Effect of Adsorption on the Contact Angle: Water-Glass System

    NASA Astrophysics Data System (ADS)

    Keshavarz, Ali; Ward, Charles A.

    2002-03-01

    The contact angle at the line formed by the intersection of solid, liquid and vapor phases is usually assumed to be only a function of temperature. This amounts to neglecting the effects of vapor adsorption. However recent experimental observations made during a Space Shuttle flight raised questions about this view. To explain the observations, it was hypothesized that in the limit of the pressure approaching the saturation vapour pressure, adsorption effects can gave rise to an approximately 20° increase in the contact angle. In a ground-based laboratory, this hypothesis examined. Nine cylinders, each with a different diameters has been partially filled with water, sealed and the miniscule height measured under isothermal conditions. By determining the interface shape from the Laplace equation that has the measured meniscus height, the value of the contact angle and pressure at the three-phase line can be inferred. An equilibrium adsorption isotherm relation is derived using a model of the adsorbate that was previously introduced by Hill. The adsorption isotherm relation this obtained contains three temperature-dependent parameters, and when used with the Gibbs adsorption equation, an expression for the contact angle in terms of these parameters is obtained. Their values at each of 5 different temperatures were determined by fitting theoretical relation to the measured contact angles. This permits the amount adsorbed in the limit of the pressure approaching the saturation vapour pressure to be calculated—a parameter range not previously explored. It also permits one to show that the contact angles measured on the Space Shuttle are completely consistent with those measured in a ground-based larboratory provided one takes adsorption into account. The results suggest the contact angle depends strongly on the pressure and that its pressure-dependence can not be neglected when the pressure at the three phase line is near the saturation vapor pressure.

  13. Increased quality factor in superconducting microstrip resonators by selective removal of the gold contact layer

    NASA Astrophysics Data System (ADS)

    Schneider, R.; Zaitsev, A. G.; Geerk, J.; Linker, G.; Ratzel, F.; Smithey, R.

    2002-02-01

    We present measurements of the unloaded quality factor of superconducting microstrip resonators at 77 K and 3.86 GHz. The resonators were made of 0.3 μm thick YBa2Cu3O7 films with a transition temperature of 90 K on both sides of ceria-buffered 3 inch sapphire wafers. In particular, we investigated the effect of a 0.3 μm thick gold contact layer on the resonator performance. It was found that the gold layer decreases the quality factor by a factor of almost 5. This result is due to an additional microwave loss in the gold film which can be quantitatively described by the impedance transformation rules for transmission lines. On the basis of the quantitative analysis, we suggest a selective removal of the contact layer by appropriate patterning in order to eliminate the extra loss without deterioration of the low-ohmic galvanic contact to the microwave housing. The experimental results demonstrate the usefulness of the proposed method. Their comparison with the calculated surface current density in the ground plane shows that the contact layer has to be in an area where the current is zero. Furthermore, the results reveal that the surface current density distribution in the ground plane and microstrip depends on the microwave power.

  14. Contact angles at the water-air interface of hydrocarbon-contaminated soils and clay minerals

    NASA Astrophysics Data System (ADS)

    Sofinskaya, O. A.; Kosterin, A. V.; Kosterina, E. A.

    2016-12-01

    Contact angles at the water-air interface have been measured for triturated preparations of clays and soils in order to assess changes in their hydrophobic properties under the effect of oil hydrocarbons. Tasks have been to determine the dynamics of contact angle under soil wetting conditions and to reveal the effect of chemical removal of organic matter from soils on the hydrophilicity of preparations. The potentialities of static and dynamic drop tests for assessing the hydrophilic-hydrophobic properties of soils have been estimated. Clays (kaolinite, gumbrine, and argillite) have been investigated, as well as plow horizons of soils from the Republic of Tatarstan: heavy loamy leached chernozem, medium loamy dark gray forest soil, and light loamy soddy-calcareous soil. The soils have been contaminated with raw oil and kerosene at rates of 0.1-3 wt %. In the uncontaminated and contaminated chernozem, capillary water capacity has been maintained for 250 days. The contact angles have been found to depend on the degree of dispersion of powdered preparation, the main type of clay minerals in the soil, the presence and amount of oxidation-resistant soil organic matter, and the soil-water contact time. Characteristic parameters of mathematical models for drop behavior on triturated preparations have been calculated. Contamination with hydrocarbons has resulted in a reliable increase in the contact angles of soil preparations. The hydrophobization of soil surface in chernozem is more active than in soils poorer in organic matter. The complete restoration of the hydrophilic properties of soils after hydrocarbon contamination is due to the oxidation of easily oxidizable organic matter at the low content of humus, or to wetting during several months in the absence of the mazut fraction.

  15. Changes in water contact angles during the first phase of setting of dental impression materials.

    PubMed

    Mondon, Matthias; Ziegler, Christiane

    2003-01-01

    The purpose of this investigation was to examine the changes in wettability of dental impression materials during setting. This study compared the properties of the initial water contact of two different dental impression materials and their subsequent development during polymerization. Two dental impression materials (Impregum Penta Soft and Aquasil) with different chemical compositions (polyether and polyvinyl siloxane, respectively) were investigated with respect to their changing wetting properties by time-resolved static contact angle measurements. Ten sets of measurements each were taken over a period of 400 seconds with 150 points of data each; the first pictures were used for further characterization of the initial interaction. With 73 degrees, Impregum Penta Soft exhibited a significantly lower contact angle, which stayed lower during the process of setting, compared to the silicone-based material. The initial interaction of the droplet showed a repulsive interaction of Aquasil with the water droplet. Impregum Penta Soft showed a more hydrophilic behavior during the process of setting compared to Aquasil and can therefore be expected to exhibit better flow properties. The method of time-resolved static contact angle measurements is a well-suited analytic instrument to monitor temporally changing wetting phenomena.

  16. Contact-dependent regulation of a Tannerella forsythia virulence factor, BspA, in biofilms.

    PubMed

    Inagaki, Satoru; Kuramitsu, Howard K; Sharma, Ashu

    2005-08-15

    Tannerella forsythia is one of the periodontal organisms implicated in the development of periodontal diseases. The surface associated and secreted protein, BspA (encoded by the bspA gene), of this bacterium is an important virulence factor. The present study was carried out to examine the regulation of the bspA gene during biofilm growth and contact stimuli encountered in interbacterial interactions. The expression levels of the bspA transcript were determined by real-time RT-PCR approach. The levels of bspA transcript were found to be significantly reduced as a result of contact stimulus and in biofilm cells relative to planktonic cells. The results of our study suggest that the likely downregulation of the BspA protein in biofilms and following contact may have implications in pathogenesis as a plausible mechanism of evasion of host immune responses.

  17. [Investigation of susceptibility of materials contacting with drinking water for microbial growth].

    PubMed

    Szczotko, Maciej; Krogulska, Bozena; Krogulski, Adam

    2009-01-01

    Main purpose of this paper was to confirm of results obtained by new method based on bioluminescence technique for determination of susceptibility of materials contacting with drinking water were repeatable. Investigation was conducted during 8 weeks in dynamic conditions using continuous flow reactor UPE. Every week swabbes from tested materials were collected and level of ATP was examined. The results obtained from the surface of tested materials were repeatable and clearly approximate to those obtained from the surface of negative control material (stainless steel, low susceptibility for microbial growth). The level of the ATP on the surface of positive control material (paraffin, large susceptibility for microbial growth) was fifty times higher than that observed on other materials. Presented investigation was the main part of validation process, which in short time will serve to initiate system of complete assessment for materials contacting with drinking water according to Council Directives 89/106/EEC and 98/83/EC requirements.

  18. Wetting and interfacial properties of water nanodroplets in contact with graphene and monolayer boron-nitride sheets.

    PubMed

    Li, Hui; Zeng, Xiao Cheng

    2012-03-27

    Born-Oppenheim quantum molecular dynamics (QMD) simulations are performed to investigate wetting, diffusive, and interfacial properties of water nanodroplets in contact with a graphene sheet or a monolayer boron-nitride (BN) sheet. Contact angles of the water nanodroplets on the two sheets are computed for the first time using QMD simulations. Structural and dynamic properties of the water droplets near the graphene or BN sheet are also studied to gain insights into the interfacial interaction between the water droplet and the substrate. QMD simulation results are compared with those from previous classic MD simulations and with the experimental measurements. The QMD simulations show that the graphene sheet yields a contact angle of 87°, while the monolayer BN sheet gives rise to a contact angle of 86°. Hence, like graphene, the monolayer BN sheet is also weakly hydrophobic, even though the BN bonds entail a large local dipole moment. QMD simulations also show that the interfacial water can induce net positive charges on the contacting surface of the graphene and monolayer BN sheets, and such charge induction may affect electronic structure of the contacting graphene in view that graphene is a semimetal. Contact angles of nanodroplets of water in a supercooled state on the graphene are also computed. It is found that under the supercooled condition, water nanodroplets exhibit an appreciably larger contact angle than under the ambient condition.

  19. Allergic contact dermatitis in children: which factors are relevant? (review of the literature).

    PubMed

    de Waard-van der Spek, Flora B; Andersen, Klaus E; Darsow, Ulf; Mortz, Charlotte G; Orton, David; Worm, Margitta; Muraro, Antonella; Schmid-Grendelmeier, Peter; Grimalt, Ramon; Spiewak, Radoslaw; Rudzeviciene, Odilija; Flohr, Carsten; Halken, Susanne; Fiocchi, Alessandro; Borrego, Luis M; Oranje, Arnold P

    2013-06-01

    Allergic contact dermatitis (ACD) in children is increasing. Sensitization to contact allergens can start in early infancy. The epidermal barrier is crucial for the development of sensitization and elicitation of ACD. Factors that may influence the onset of sensitization in children are atopic dermatitis, skin barrier defects and intense or repetitive contact with allergens. Topical treatment of ACD is associated with cutaneous sensitization, although the prevalence is not high. ACD because of haptens in shoes or shin guards should be considered in cases of persistent foot eruptions or sharply defined dermatitis on the lower legs. Clinical polymorphism of contact dermatitis to clothing may cause difficulties in diagnosing textile dermatitis. Toys are another potentially source of hapten exposure in children, especially from toy-cosmetic products such as perfumes, lipstick and eye shadow. The most frequent contact allergens in children are metals, fragrances, preservatives, neomycin, rubber chemicals and more recently also colourings. It is very important to remember that ACD in young children is not rare, and should always be considered when children with recalcitrant eczema are encountered. Children should be patch-tested with a selection of allergens having the highest proportion of positive, relevant patch test reactions. The allergen exposure pattern differs between age groups and adolescents may also be exposed to occupational allergens. The purpose of this review is to alert the paediatrician and dermatologist of the frequency of ACD in young children and of the importance of performing patch tests in every case of chronic recurrent or therapy-resistant eczema in children.

  20. A Facile All-Solution-Processed Surface with High Water Contact Angle and High Water Adhesive Force.

    PubMed

    Chen, Mei; Hu, Wei; Liang, Xiao; Zou, Cheng; Li, Fasheng; Zhang, Lanying; Chen, Feiwu; Yang, Huai

    2017-07-12

    A series of sticky superhydrophobicity surfaces with high water contact angle and high water adhesive force is facilely prepared via an all-solution-processed method based on polymerization-induced phase separation between liquid crystals (LCs) and epoxy resin, which produces layers of epoxy microspheres (EMSs) with nanofolds on the surface of a substrate. The morphologies and size distributions of EMSs are confirmed by scanning electron microscopy. Results reveal that the obtained EMS coated-surface exhibits high apparent contact angle of 152.0° and high water adhesive force up to 117.6 μN. By varying the composition of the sample or preparing conditions, the sizes of the produced EMSs can be artificially regulated and, thus, control the wetting properties and water adhesive behaviors. Also, the sticky superhydrophobic surface exhibits excellent chemical stability, as well as long-term durability. Water droplet transportation experiments further prove that the as-made surface can be effectively used as a mechanical hand for water transportation applications. Based on this, it is believed that the simple method proposed in this paper will pave a new way for producing a sticky superhydrophobic surface and obtain a wide range of use.

  1. Use of Atomic Oxygen for Increased Water Contact Angles of Various Polymers for Biomedical Applications

    NASA Technical Reports Server (NTRS)

    Beger, Lauren; Roberts, Lily; deGroh, Kim; Banks, Bruce

    2007-01-01

    In the low Earth orbit (LEO) space environment, spacecraft surfaces can be altered during atomic oxygen exposure through oxidation and erosion. There can be terrestrial benefits of such interactions, such as the modification of hydrophobic or hydrophilic properties of polymers due to chemical modification and texturing. Such modification of the surface may be useful for biomedical applications. For example, atomic oxygen texturing may increase the hydrophilicity of polymers, such as chlorotrifluoroethylene (Aclar), thus allowing increased adhesion and spreading of cells on textured Petri dishes. The purpose of this study was to determine the effect of atomic oxygen exposure on the hydrophilicity of nine different polymers. To determine whether hydrophilicity remains static after atomic oxygen exposure or changes with exposure, the contact angles between the polymer and a water droplet placed on the polymer s surface were measured. The polymers were exposed to atomic oxygen in a radio frequency (RF) plasma asher. Atomic oxygen plasma treatment was found to significantly alter the hydrophilicity of non-fluorinated polymers. Significant decreases in the water contact angle occurred with atomic oxygen exposure. Fluorinated polymers were found to be less sensitive to changes in hydrophilicity for equivalent atomic oxygen exposures, and two of the fluorinated polymers became more hydrophobic. The majority of change in water contact angle of the non-fluorinated polymers was found to occur with very low fluence exposures, indicating potential cell culturing benefit with short treatment time.

  2. Effects of water chemistry and surface contact on the toxicity of silver nanoparticles to Bacillus subtilis.

    PubMed

    Yi, Jun; Cheng, Jinping

    2017-07-01

    The growing use of silver nanoparticles (AgNPs) has created concerns about its potential impacts on natural microbial communities. In this study, the physicochemical properties of AgNPs and its toxicity on natural bacteria Bacillus subtilis (B. subtilis) were investigated in aqueous conditions. The characterization data showed that AgNPs highly aggregated in aqueous conditions, and the hydrodynamic diameter of AgNPs in aqueous conditions was larger than its primary size. The studied AgNPs was less toxic to B. subtilis in estuarine water as compared to that in Milli-Q water and artificial seawater, which might be due to the observed enhanced aggregation of AgNPs in estuarine water. The toxicity of AgNPs to B. subtilis was greatly reduced when their surface contact was blocked by a dialysis membrane. Scanning electron microscope images showed that exposure contact to AgNPs resulted in damage of the microbial cell wall and enhanced formation of fibrillar structures. These results suggest that particle-cell contact is largely responsible for the observed toxicity of AgNPs in B. subtilis. This study can help to understand the potential impacts of AgNPs to natural microbes, especially in the complex aquatic environments.

  3. Water Exposure is a Common Risk Behavior Among Soft and Gas-Permeable Contact Lens Wearers

    PubMed Central

    Richdale, Kathryn; Mitchell, Gladys Lynn; Kinoshita, Beth T.; Lam, Dawn Y.; Wagner, Heidi; Sorbara, Luigina; Chalmers, Robin L.; Collier, Sarah A.; Cope, Jennifer R.; Rao, Maya M.; Beach, Michael J.; Yoder, Jonathan S.

    2017-01-01

    Purpose: To understand soft contact lens (SCL) and gas-permeable (GP) lens wearers' behaviors and knowledge regarding exposure of lenses to water. Methods: The Contact Lens Risk Survey (CLRS) and health behavior questions were completed online by a convenience sample of 1056 SCL and 85 GP lens wearers aged 20 to 76 years. Participants were asked about exposing their lenses to water and their understanding of risks associated with these behaviors. Chi-square analyses examined relationships between patient behaviors and perceptions. Results: GP lens wearers were more likely than SCL wearers to ever rinse or store lenses in water (rinsing: 91% GP, 31% SCL, P < 0.001; storing: 33% GP, 15% SCL P < 0.001). Among SCL wearers, men were more likely to store (24% vs. 13%, P = 0.003) or rinse (41% vs. 29%, P = 0.012) their lenses in water. Showering while wearing lenses was more common in SCL wearers (86%) than GP lens wearers (67%) (P < 0.0001). Swimming while wearing lenses was reported by 62% of SCL wearers and 48% of GP lens wearers (P = 0.027). Wearers who rinsed (SCL; P < 0.0001, GP; P = 0.11) or stored lenses in water (SCL; P < 0.0001, GP P = 0.007) reported that this behavior had little or no effect on their infection risk, compared with those who did not. Both SCL (P < 0.0001) and GP lens wearers (P < 0.0001) perceived that distilled water was safer than tap water for storing or rinsing lenses. Conclusions: Despite previously published evidence of Acanthamoeba keratitis' association with water exposure, most SCL, and nearly all GP lens wearers, regularly expose their lenses to water, with many unaware of the risk. PMID:28410356

  4. Energetics of the contact minimum configuration of two hard spheres in water

    NASA Astrophysics Data System (ADS)

    Graziano, Giuseppe

    2017-10-01

    Changes in thermodynamic functions for the formation of the contact minimum, cm, configuration of two hard spheres (i.e., two cavities) are calculated by means of a physically-based geometric approach over a large temperature range. The decrease in water accessible surface area due to cm formation causes a gain in translational entropy of water molecules, driving the process. This produces a negative Gibbs energy change, whose magnitude slightly increases with temperature. The process is exothermic due to the decrease in hydration shell size, but this enthalpy change is entirely compensated by a corresponding entropy contribution.

  5. Effect of water desorption on the rheology and dynamic response of human hair to a non-contact impact.

    PubMed

    Jamart, J; Djaghloul, M; Bergheau, J M; Zahouani, H

    2015-06-01

    Human hair is a non-homogeneous complex material made of keratin fibers oriented along the longitudinal axis which offer anisotropic mechanical properties. Nowadays, it is possible to measure the mechanical properties of hairs with the classical tests, but most often, these tests are destructive and make hard to measure the influence of some external factors or treatments on the behavior of a same hair fiber. In the current paper, vibrations induced by a non-contact impact have been utilized as a representative response of the mechanical behavior of hair. The characteristics of the vibratory response allow measuring the variation in the mechanical properties and the instantaneous effect of an external factor on the properties of a same sample. First, load relaxation tests have been performed on hair samples after moisturization and for different times of an air-drying process in order to characterize the change in the visco-elastic behavior of hair during the water desorption. Other hair samples have been tested with our non-contact impact and vibration technique in order to observe the change in the vibratory response during the water desorption. The vibratory response has then been correlated to the mechanical properties of the hair fiber. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Movement and evaporation of water droplets under conditions typical for heat-exchange chambers of contact water heaters

    NASA Astrophysics Data System (ADS)

    Volkov, R. S.; Kuznetsov, G. V.; Strizhak, P. A.

    2016-09-01

    The macroscopic regularities and integrated characteristics of the motion and evaporation of sprayed water droplets in the field of high-temperature (1100 K) combustion products under the conditions typical for water heaters of contact type (economizers) were studied using a cross-correlation complex working on the basis of panoramic optical methods (particle image velocimetry, particle tracking velocimetry, shadow photography) and high-speed (105 fps) Phantom video cameras. High-speed video recording devices with specialized software were used for continuously monitoring the motion and evaporation of droplets. Titanium dioxide nanopowder tracer particles were introduced to determine the rate of high-temperature gases. The characteristic distances covered by water droplets before their full retardation in the counter-flow of high-temperature combustion products were determined. The integrated dependences were obtained, and the main characteristics of evaporation were determined, which allow one to predict the intensity of the phase transformations of droplets (with sizes of 0.05-0.5 mm) and the distances covered by them before they completely turn in the opposite direction under the conditions corresponding to the heat-exchange chambers of contact water heaters: the vapor-droplet rate 1-5 m/s, gas flow rate 0.5-2 m/s, and gas temperature ~1100 K. Approximating expressions were derived to predict the characteristics of the processes. The performance of the economizers under study can be significantly increased by using the obtained experimental dependences, the corresponding approximating expressions, and the resulting conclusions. Conditions were determined under which the influence of phase transformations on retardation exceeds the contribution of the counter-motion and active retardation and evaporation of water droplets occur in the heat-exchange chambers of contact water heaters of typical sizes.

  7. Breakpoint chlorination and free-chlorine contact time: implications for drinking water N-nitrosodimethylamine concentrations.

    PubMed

    Charrois, Jeffrey W A; Hrudey, Steve E

    2007-02-01

    North American drinking water utilities are increasingly incorporating alternative disinfectants, such as chloramines, in order to comply with disinfection by-product (DBP) regulations. N-Nitrosodimethylamine (NDMA) is a non-halogenated DBP, associated with chloramination, having a drinking water unit risk two to three orders of magnitude greater than currently regulated halogenated DBPs. We quantified NDMA from two full-scale chloraminating water treatment plants in Alberta between 2003 and 2005 as well as conducted bench-scale chloramination/breakpoint experiments to assess NDMA formation. Distribution system NDMA concentrations varied and tended to increase with increasing distribution residence time. Bench-scale disinfection experiments resulted in peak NDMA production near the theoretical monochloramine maximum in the sub-breakpoint region of the disinfection curve. Breakpoints for the raw and partially treated waters tested ranged from 1.9:1 to 2.4:1 (Cl(2):total NH(3)-N, M:M). Bench-scale experiments with free-chlorine contact (2h) before chloramination resulted in significant reductions in NDMA formation (up to 93%) compared to no free-chlorine contact time. Risk-tradeoff issues involving alternative disinfection methods and unregulated DBPs, such as NDMA, are emerging as a major water quality and public health information gap.

  8. Is the wear factor in total joint replacements dependent on the nominal contact stress in ultra-high molecular weight polyethylene contacts?

    PubMed

    Vassiliou, K; Unsworth, A

    2004-01-01

    The exact dependence of wear factor on contact stress, load and apparent contact area is much disputed in the literature. This study attempts to solve this dispute. Pin-on-plate studies of ultra high molecular weight polyethylene against stainless steel were conducted under different combinations of load (33-250 N), nominal stress (0.56-12.73 MPa) and face diameter, as well as two tests where both stress and load were kept constant, while the diameter was changed. For these tests the centre of the pin face was bored out to create four different average pin diameters with similar face areas. Diameter and load were found to have no significant effect on the wear factor, while the wear factor decreased with increasing contact stress according to the relation K = 2 x 10(-6) sigma(-0.84).

  9. Proteolytic properties of single-chain factor XII: a mechanism for triggering contact activation.

    PubMed

    Ivanov, Ivan; Matafonov, Anton; Sun, Mao-Fu; Cheng, Qiufang; Dickeson, S Kent; Verhamme, Ingrid M; Emsley, Jonas; Gailani, David

    2017-03-16

    When blood is exposed to variety of artificial surfaces and biologic substances, the plasma proteins factor XII (FXII) and prekallikrein undergo reciprocal proteolytic conversion to the proteases αFXIIa and α-kallikrein by a process called contact activation. These enzymes contribute to host-defense responses including coagulation, inflammation, and fibrinolysis. The initiating event in contact activation is debated. To test the hypothesis that single-chain FXII expresses activity that could initiate contact activation, we prepared human FXII variants lacking the Arg353 cleavage site required for conversion to αFXIIa (FXII-R353A), or lacking the 3 known cleavage sites at Arg334, Arg343, and Arg353 (FXII-T, for "triple" mutant), and compared their properties to wild-type αFXIIa. In the absence of a surface, FXII-R353A and FXII-T activate prekallikrein and cleave the tripeptide S-2302, demonstrating proteolytic activity. The activity is several orders of magnitude weaker than that of αFXIIa. Polyphosphate, an inducer of contact activation, enhances PK activation by FXII-T, and facilitates FXII-T activation of FXII and FXI. In plasma, FXII-T and FXII-R353A, but not FXII lacking the active site serine residue (FXII-S544A), shortened the clotting time of FXII-deficient plasma and enhanced thrombin generation in a surface-dependent manner. The effect was not as strong as for wild-type FXII. Our results support a model for induction of contact activation in which activity intrinsic to single-chain FXII initiates αFXIIa and α-kallikrein formation on a surface. αFXIIa, with support from α-kallikrein, subsequently accelerates contact activation and is responsible for the full procoagulant activity of FXII.

  10. The use of contact lenses during water-polo play: a 20-year study of Japanese college players.

    PubMed

    Komori, Yasuka; Kobayashi, Daisuke; Murase, Yosuke; Enomoto, Itaru; Takagi, Hideki; Kono, Ichiro

    2013-01-01

    This study investigated the extent of contact-lens use in Japanese college water-polo male players over 20 years (1991-2011, once every five years). Information about the use of contact lenses during play and the types of contact lens was obtained through a self-report questionnaire. The proportion of contact lens use among the players while playing water polo differed from 1991 to 2011 (χ2(4) = 25.28, P < 0.001, Cohen's d = 0.63). Fifty-four per cent of the players used contact lenses while playing in 1991 (P < 0.001); more than 74% in 1996; 89% in 2001; 84% in 2006; and 86% in 2011. While 96% of the contact lenses used by the players in 1991 were the soft type, 74%, 92%, 86%, and 88% of the contact lenses used in 1996, 2001, 2006, and 2011, respectively, were the disposable type. These findings indicated a high percentage of players were using contact lenses while playing water polo between 1996 and 2011. This could be because the majority of players used disposable lenses. The results suggest that increasing use of contact lenses by water-polo players is beneficial.

  11. Acanthamoeba keratitis in noncompliant soft contact lenses users: Genotyping and risk factors, a study from Cairo, Egypt.

    PubMed

    Taher, Eman E; Méabed, Eman M H; Abdallah, Islam; Abdel Wahed, Wafaa Y

    2017-09-28

    Acanthamoeba keratitis (AK) is a severe corneal infection that may occur as a serious outcome of improper use of contact lenses (CL). The study aimed to diagnose AK in soft CL users presenting with infectious keratitis, and to identify the prevalent genotypes isolated from different cases. Another aim was to determine the CL hygiene-related risk behaviors, and to explore the risk of water exposure for developing AK. A cross sectional study was performed. A questionnaire was carried out including 260 clinically diagnosed cases as infectious keratitis (170 females and 90 males); all of them were soft CL users for the suspected risk factors. Corneal scrapes from the affected eyes were cultured to diagnose bacterial and AK. PCR was performed and the amplified products were sequenced and compared with GenBank data. The parasite was positively amplified from 32 samples (12.3%). Acanthamoeba T4 genotype was identified in 27/32 (84.4%) of isolates. Other detected genotypes belonged to T5 and T3 genotypes at rates of 9.4%, and 6.25%, respectively. The most important risk factors associated with development of AK were female sex, sleeping while wearing CL, and exposure to water resources through different practices. These practices included rinsing the CL case in tap water, swimming and/or showering while wearing CL, using multipurpose solution for cleaning the lenses, using water from over-building tanks. Rubbing the eyes due to discomfort when applying CL was an additional important risk factor associated with AK. The protective factor was regular hand washing before using CL. CL users were more exposed to AK and should gain enough health education regarding proper lens hygiene and dangers of tap water exposure. Copyright © 2017. Published by Elsevier Ltd.

  12. Disposable contact lens use as a risk factor for microbial keratitis

    PubMed Central

    Radford, C.; Minassian, D.; Dart, J.

    1998-01-01

    AIMS—A case-control study was performed to evaluate soft contact lens (SCL) wear modality as a risk factor for microbial keratitis.
METHODS—Contact lens wearers presenting as new patients to Moorfields Eye Hospital accident and emergency department during a 12 month period completed a self administered questionnaire detailing demographic data and contact lens use habits. Cases were patients with a clinical diagnosis of SCL related microbial keratitis. Controls were SCL users attending with disorders unrelated to contact lens wear. Odds ratios (estimates of relative risks) and 95% confidence limits (CL) were calculated through multivariable logistic regression analysis.
RESULTS—There were 89 cases and 566 controls. A substantially increased risk with 1-4 weekly disposable SCL compared with non-disposable SCL was identified among both daily wear (DW) (odds ratio =3.51, 95% CL 1.60-7.66, p=0.002) and extended wear (odds ratio 4.76, 95% CL 1.52-14.87, p=0.007) users after adjustment for demographic, lens use and hygiene variables. Other significant factors among DW users were "occasional" overnight use, use of chlorine based (as opposed to other chemical) systems in combination with poor storage case hygiene, and irregular disinfection.
CONCLUSION—Properties of some disposable SCL may be partly responsible for these excess risks. It is also possible, however, that this finding is largely a reflection of widespread complacency among patients and practitioners with respect to disposable SCL fitting and use.

 Keywords: microbial keratitis; disposable contact lenses PMID:9924331

  13. Contact factor deficiencies and cardiopulmonary bypass surgery: detection of the defect and monitoring of heparin.

    PubMed

    van Veen, Joost Jair; Laidlaw, Stuart; Swanevelder, Justin; Harvey, Nicholas; Watson, Chris; Kitchen, Steve; Makris, Mike

    2009-03-01

    Contact factor pathway deficiencies do not cause surgical bleeding but make heparin monitoring by the activated partial thromboplastin time (APTT) and activated clotting time (ACT) unreliable. Heparin monitoring during cardiopulmonary bypass (CPB) surgery in these patients is particularly challenging. Here we describe heparin monitoring during CPB using the chromogenic anti Xa assay in two patients with severe factor XII deficiency (FXII < 0.01 U/mL) and one patient with severe prekallikrein (PK) deficiency (PK < 0.01 U/mL). Anti Xa levels of the three patients during CPB varied between 3.8 and 4.8 U/mL in keeping with a control group (mean anti Xa 4.5 U/mL and ACT > 480 s). There were no bleeding or thrombotic complications. We also found that detection of severe PK deficiency by the APTT in the PK deficient patient was dependent on the reagent used and discuss the sensitivity of different APTT reagents for contact factor deficiencies. We conclude that the sensitivity of APTT methods for contact pathway deficiencies is highly variable and although insensitivity is not a clinical problem in terms of bleeding, it can be a cause of discrepancy between different APTT reagents and the ACT. This can lead to confusion about a possible haemorrhagic tendency and delays in surgery. If these patients need to undergo cardiac surgery requiring high dose heparin treatment, monitoring by chromogenic anti Xa assay is a good alternative.

  14. Factors Affecting Atrazine Concentration and Quantitative Determination in Chlorinated Water

    EPA Science Inventory

    Although the herbicide atrazine has been reported to not react measurably with free chlorine during drinking water treatment, this work demonstrates that at contact times consistent with drinking water distribution system residence times, a transformation of atrazine can be obser...

  15. Factors Affecting Atrazine Concentration and Quantitative Determination in Chlorinated Water

    EPA Science Inventory

    Although the herbicide atrazine has been reported to not react measurably with free chlorine during drinking water treatment, this work demonstrates that at contact times consistent with drinking water distribution system residence times, a transformation of atrazine can be obser...

  16. Urban schistosomiasis: morbidity, sociodemographic characteristics and water contact patterns predictive of infection.

    PubMed

    Firmo, J O; Lima Costa, M F; Guerra, H L; Rocha, R S

    1996-12-01

    Schistosomiasis (Schistosoma mansoni) is classically described as a rural disease that occurs in areas with poor sanitary conditions. This cross-sectional study was undertaken in a suburban area of a large industrialized city in Brazil (Belo Horizonte), aiming at examining epidemiological characteristics of schistosomiasis in an urban setting. A simple random sample of 658/1896 dwellings was selected and 3049/3290 (92.7%) residents were submitted to stool examination. Of 518 eligible infected cases and 518 uninfected controls, 87.1% and 89.9% participated in the study, respectively. The prevalence of S. mansoni infection was 20%, predominantly low egg counts in stools; no cases of splenomegaly were found. Signs and symptoms associated with infection were bloody stools (odds ratio [OR] = 8.0) and hardened palpable liver at the middle clavicular and at the middle sternal life (OR = 5.5 and 8.0 respectively). Sociodemographic variables and water contacts predictive of infection were age (10-19 and > or = 20 yrs; OR = 7.1 and 3.3, respectively), gender (male; OR = 3.1), contacts for swimming and/or playing (twice a month or less and more than twice a month; OR = 2.2 and 3.0, respectively) and residence in Belo Horizonte (born in the City; OR = 2.5). Ninety per cent of dwellings had a piped water supply; no association between water supply and infection was found. Our results emphasize the need for schistosomiasis control measures focusing on water contacts for leisure purposes in this industrialized urban area.

  17. Water-vapor effects on friction of magnetic tape in contact with nickel-zinc ferrite

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1984-01-01

    The effects of humidity of moist nitrogen on the friction and deformation behavior of magnetic tape in contact with a nickel-zinc ferrite spherical pin were studied. The results indicate that the coefficient of friction is markedly dependent on the ambient relative humidity. Although the coefficient of friction remains low below 40-percent relative humidity, it increases rapidly with increasing relative humidity above 40 percent. The general ambient environment of the tape does not have any effect on the friction behavior if the area where the tape is in sliding contact with the ferrite pin is flooded with controlled nitrogen. The response time for the friction of the tape to humidity changes is about 10 sec. The effect of friction as a function of relative humidity on dehumidifying is very similar to that on humidifying. A surface softening of the tape due to water vapor increases the friction of the tape.

  18. In vitro adhesion of Acanthamoeba castellanii to soft contact lenses depends on water content and disinfection procedure.

    PubMed

    Reverey, Julia F; Fromme, Roland; Leippe, Matthias; Selhuber-Unkel, Christine

    2014-08-01

    To compare the potential of different soft contact lenses to be contaminated with Acanthamoeba castellanii as a function of material parameters and cleaning procedures. Different unworn soft hydrogel and silicone hydrogel contact lenses were incubated with human pathogenic A. castellanii. The adhesion of the acanthamoebae was investigated on the contact lenses and put into relation to their material parameters. The efficacy of a recommended contact lens cleaning procedure in reducing A. castellanii adhesion was investigated. We found that material parameters such as elastic modulus, silicone content, ionic properties and swelling do not influence the adhesion of acanthamoebae to soft contact lenses. A material parameter that influenced adhesion significantly was the water content of the lens. With increasing water content, the adhesion of acanthamoebae increased. By following the cleaning instructions of the manufacturer the contamination of the lenses with A. castellanii could be reduced to a minimum, as shown both on contact lenses and in control experiments. With this study we show that for the tested lenses, the adhesion of A. castellanii to contact lenses is independent of the silicone content of the lens, but depends nonlinearly on the water content of the lens. Furthermore, we demonstrate that applying proper lens cleaning procedures minimizes the risk of acanthamoebae adhesion to contact lenses. Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  19. The Water-Wheel IR (WIR): A Contact Survey Experiment for Water and Carbonates on Mars

    NASA Technical Reports Server (NTRS)

    Wang, Alian; Haskin, Larry A.; Freeman, John; Dong, Edward X.; Kuebler, Karla E.

    2004-01-01

    Minimum requirements for life include water and accessible carbon. Mars has both in its polar caps and atmosphere. Water (or water-equivalent hydrogen) is present at shallow depths (approx. 10-20 cm) at latitudes =60 and is heterogeneously distributed in other parts of Mars [1]. Mars may have once had surface water that could plausibly have produced carbonate deposits [2-5]. Mars shows signs of hydrothermal activity [6-8] that may have affected soil composition [9, 10]. The Thermal Emission Spectrometer on the Mars Global Surveyor found large and small patches of hematite that may have been water-borne or water-derived [11, 12]. Current orbiting spacecraft (MGS & Odyssey) have not found massive carbonate deposits, however [13]. Shales and limestones, which we associate with moist and benign environments on Earth, are apparently not abundant on Mars. Both carbonate and organic carbon occur as alteration products in Martian meteorites of igneous origin [14]. One study of MGS-TES data suggests 2-5 wt% carbonates (mainly MgCO3) in surface dust, but found no concentrated source [15]. Carbonates and H2O/OH bearing minerals will be sought by the mini-TES and Mossbauer experiments on the Mars Exploration Rovers, one of which landed successfully on Mars on January 3.

  20. The Water-Wheel IR (WIR): A Contact Survey Experiment for Water and Carbonates on Mars

    NASA Technical Reports Server (NTRS)

    Wang, Alian; Haskin, Larry A.; Freeman, John; Dong, Edward X.; Kuebler, Karla E.

    2004-01-01

    Minimum requirements for life include water and accessible carbon. Mars has both in its polar caps and atmosphere. Water (or water-equivalent hydrogen) is present at shallow depths (approx. 10-20 cm) at latitudes =60 and is heterogeneously distributed in other parts of Mars [1]. Mars may have once had surface water that could plausibly have produced carbonate deposits [2-5]. Mars shows signs of hydrothermal activity [6-8] that may have affected soil composition [9, 10]. The Thermal Emission Spectrometer on the Mars Global Surveyor found large and small patches of hematite that may have been water-borne or water-derived [11, 12]. Current orbiting spacecraft (MGS & Odyssey) have not found massive carbonate deposits, however [13]. Shales and limestones, which we associate with moist and benign environments on Earth, are apparently not abundant on Mars. Both carbonate and organic carbon occur as alteration products in Martian meteorites of igneous origin [14]. One study of MGS-TES data suggests 2-5 wt% carbonates (mainly MgCO3) in surface dust, but found no concentrated source [15]. Carbonates and H2O/OH bearing minerals will be sought by the mini-TES and Mossbauer experiments on the Mars Exploration Rovers, one of which landed successfully on Mars on January 3.

  1. Prognostic factors for prediction of follow-up outcome of contact granuloma.

    PubMed

    Jin, Young Ju; Lee, Sun Joo; Lee, Won Yong; Jeong, Woo-Jin; Ahn, Soon-Hyun

    2014-07-01

    Although the frequent spontaneous resolution of contact granuloma is reported, the prognostic factor that can predict the possibility of resolution is not clear. We retrospectively analyzed the hospital records and laryngoscopic photos of 52 patients who were diagnosed with contact granuloma between May 2003 and June 2012. The reflux finding score and the shape of the granuloma were analyzed based on the initial laryngoscopy images; additionally, age, gender, chief complaint, and the side afflicted were also analyzed. Of the 52 patients, 40 who were treated conservatively were analyzed. Their mean age was 57.6 years and the mean follow-up period was 28.6 weeks. There was male predominance (87.5%), and the left side was more commonly afflicted (60.0%). Factors significantly associated with resolution included width/height ratio (P = 0.012) and gender (P = 0.048), but not reflux finding score (P = 0.713) or etiology (P = 0.382). So with this data, resolution of contact granuloma is highly probable in cases where the granuloma has a narrow base and the gender is female.

  2. Factors associated with dog ownership and contact with dogs in a UK community

    PubMed Central

    Westgarth, Carri; Pinchbeck, Gina L; Bradshaw, John WS; Dawson, Susan; Gaskell, Rosalind M; Christley, Robert M

    2007-01-01

    Background Dogs are popular pets in many countries. Identifying differences between those who own dogs or have contact with dogs, and those who do not, is useful to those interested in the human-animal bond, human health and for provision of veterinary services. This census-based, epidemiological study aimed to investigate factors associated with dog ownership and contact with dogs, in a semi-rural community of 1278 households in Cheshire, UK. Results Twenty-four percent of households were identified as dog-owning and 52% owned a pet of some type. Multivariable logistic regression suggested that households were more likely to own a dog if they had more occupants (five or more); if they had an adult female household member; or if they owned a horse. The age structure of the households was also associated with dog ownership, with households containing older children (between six and 19 years of age) and young adults (between 20 and 29 years of age), more likely to own dogs. We also found that dog owning households were more likely to be multi-dog households than single-dog if they also owned a cat or a bird, or if the household contained a person of 20–29 years old. Dog owners reported increased contact with dogs, other than their own, compared to those that did not own dogs and this contact appeared to be mainly through walking. Conclusion Some household types are more likely to own a dog than others. This study supports the suggestion that dogs are more common in families who have older children (6–19 years), as has been generally observed in other countries. Dog owners are also more likely to have contact with dogs other than their own, compared with those not owning a dog. PMID:17407583

  3. [Risk factors for contact lens-related microbial keratitis: A multicenter case-control study].

    PubMed

    Becmeur, P H; Abry, F; Bourcier, T; Meyer, N; Sauer, A

    2017-03-01

    Currently, the most feared complication by ophthalmologists of contact lens (CL) wear is microbial keratitis (MK), even though its incidence remains low. It is also a significant financial burden for society. This study aimed to identify the risk factors for CL-related MK especially with regard to hygiene and pattern of use, in a large, prospective, multicenter, case-control study. A multicenter retrospective case-control study was designed. The CL-related MK subpopulation (case) was compared with healthy CL wearers (control) using a 52-item anonymous questionnaire designed to determine subject demographics, lens wear history, lens type and disinfection solution, fitting, patient education, hygiene and maintenance of contact lenses, and patient history. Univariate logistic regression analysis was performed to compare both groups. The study included 497 cases and 364 controls. The risk factors associated with the greatest increased odds of CL-related MK were as follows: extended wear (OR=2.96 [1.65-5.33], P<0.001), occasional overnight lens use (OR=6.37 [4,55-8.90], P<0.001), fitting by an optician (OR=1.97 [1.38-2.83], P<0.001), absence of ophthalmologic exam (OR=6.56 [2-22], P<0.01) or no training in handling the contact lens (OR=4.47 [2.27-8.77], P<0.01), use of optician's disinfection solution (OR=5.55 [3.12-9.85], P<0.001), mixing solutions ("topping off") (OR=4.68 [2.73-8.04], P<0.001), no case replacement (OR=3.95 [2.28-6.82] P<0.01), no compliance with hygiene rules and smoking (OR=2.29 [1.67-3.14], P<0.01). The protective factors associated with the greatest reduction in OR were female gender (OR=0.49 [0.36-0.66], P<0.01), hypermetropia (OR=0.28 [0.16-0.48], P=0.01), rigid contact lens wear, fitting by an ophthalmologist, written and verbal instruction, and daily case maintenance. The knowledge of these risks factors incentivizes action at all levels to reduce the incidence of MK, from the prescriber to the patient, including the type of CL, case and

  4. Diarrhoea in close contacts as a risk factor for childhood haemolytic uraemic syndrome. The CPKDRC co-investigators.

    PubMed Central

    Rowe, P. C.; Orrbine, E.; Lior, H.; Wells, G. A.; McLaine, P. N.

    1993-01-01

    To determine whether the risk factors for childhood haemolytic uraemic syndrome (HUS) are similar to risk factors previously reported for Escherichia coli O 157. H7 gastroenteritis, we conducted a case-control study at eight paediatric hospitals in the summer of 1990. Thirty-four consecutive children with HUS were prospectively enrolled; all had diarrhoea and 88% had laboratory evidence of exposure to verotoxin-producing E. coli (VTEC). The 102 controls were otherwise healthy children with minor acute injuries. Parents of all subjects responded to a questionnaire about each child's exposure to various foods, methods of food preparation, sources of water, travel, and individuals with diarrhoea. Children with HUS were significantly more likely than controls to have had close contact with an individual with diarrhoea in the 2 weeks before the onset of illness (74 v. 29%, P < 0.00001; odds ratio 7.0, 95% CI 2.7-18.5). The onset of diarrhoea in the contacts occurred a median of 6 days (range, 1- > 14 days) before the onset of diarrhoea in the HUS patients. Exposure to undercooked ground meat was not significantly more common in the patients with HUS (15 v. 8%; P = 0.05). These data provide evidence consistent with person-to-person transmission of VTEC in a substantial proportion of episodes of childhood HUS. PMID:8432328

  5. Microbiological Water Quality in Relation to Water-Contact Recreation, Cuyahoga River, Cuyahoga Valley National Park, Ohio, 2000 and 2002

    USGS Publications Warehouse

    Bushon, Rebecca N.; Koltun, G.F.

    2004-01-01

    The microbiological water quality of a 23-mile segment of the Cuyahoga River within the Cuyahoga Valley National Park was examined in this study. This segment of the river receives discharges of contaminated water from stormwater, combined-sewer overflows, and incompletely disinfected wastewater. Frequent exceedances of Ohio microbiological water-quality standards result in a health risk to the public who use the river for water-contact recreation. Water samples were collected during the recreational season of May through October at four sites on the Cuyahoga River in 2000, at three sites on the river in 2002, and from the effluent of the Akron Water Pollution Control Station (WPCS) both years. The samples were collected over a similar range in streamflow in 2000 and 2002. Samples were analyzed for physical and chemical constituents, as well as the following microbiological indicators and pathogenic organisms: Escherichia coli (E. coli), Salmonella, F-specific and somatic coliphage, enterovirus, infectious enterovirus, hepatitis A virus, Clostridium perfringens (C. perfringens), Cryptosporidium, and Giardia. The relations of the microorganisms to each other and to selected water-quality measures were examined. All microorganisms analyzed for, except Cryptosporidium, were detected at least once at each sampling site. Concentrations of E. coli exceeded the Ohio primary-contact recreational standard (298 colonies per 100 milliliters) in approximately 87 percent of the river samples and generally were higher in the river samples than in the effluent samples. C. perfringens concentrations were positively and significantly correlated with E. coli concentrations in the river samples and generally were higher in the effluent samples than in the river samples. Several of the river samples that met the Ohio E. coli secondary-contact recreational standard (576 colonies per 100 milliliters) had detections of enterovirus, infectious enterovirus, hepatitis A virus, and

  6. Linking fractional wettability and contact angle dynamics in water repellent soils

    NASA Astrophysics Data System (ADS)

    Beatty, Sarah; Smith, James

    2016-04-01

    Dynamic soil water repellency has become a highly documented soil phenomenon across a range of environmental conditions and investigated within a range of disciplines. With global climate change at the environmental science fore, there is growing concern and need for accurate quantification of fundamental soil hydraulic properties and model parameterization. In the presence of soil water repellency, however, substantial unknowns remain in terms of characterizing repellency and drawing linkages to fundamental hydraulic parameters. This is often related to the complexity of investigating soil water repellency, which is often a challenging environment because of its spatially and temporally variable nature. To help bridge this gap, this work reports on different approaches using various technologies to explore opportunities that yield greater quantification and parametrization of soil water repellency in natural hydrologic systems at different scales. These approaches include X-ray microtomography (μXCT), Axisymmetric Drop Shape Analysis (ADSA), Drop Penetration tests (MED/WDPT), and Tension Infiltrometry. This work has shown the strength of conceptually linking contact angle dynamics and fractional wettability as a means to understand the nature of infiltration in water repellent soils and provide a mechanistic foundation upon which repellency can be quantified and related to fundamental hydraulic properties. Contact angle dynamics and fractional wettability are complimentary terminology that appear in the multiphase flow and soil physics literature, but have largely/essentially only been applied in synthetic systems. Their utility in natural environments is potentially significant and conceptually useful since they can readily incorporate existing characterizations while providing greater opportunity for articulating and defining specific behaviours in systems with high spatial and temporal heterogeneity.

  7. Patterns of intestinal schistosomiasis among mothers and young children from Lake Albert, Uganda: water contact and social networks inferred from wearable global positioning system dataloggers.

    PubMed

    Seto, Edmund Y W; Sousa-Figueiredo, José C; Betson, Martha; Byalero, Chris; Kabatereine, Narcis B; Stothard, J Russell

    2012-11-01

    The establishment of a national control programme (NCP) in Uganda has led to routine treatment of intestinal schistosomiasis with praziquantel in the communities along Lake Albert. However, because regular water contact remains a way of life for these populations, re-infection continues to mitigate the sustainability of the chemotherapy-based programme. A six-month longitudinal study was conducted in one Lake Albert community with the aim of characterizing water contact exposure and infection among mothers and their young preschool-aged children as the latter are not yet formally included within the NCP. At baseline the cohort of 37 mothers, 36 preschool-aged children had infection prevalences of 62% and 67%, respectively, which diminished to 20% and 29%, respectively, at the 6-month post-treatment follow-up. The subjects wore global positioning system (GPS) datalogging devices over a 3-day period shortly after baseline, allowing for the estimation of time spent at the lakeshore as an exposure metric, which was found to be associated with prevalence at follow-up (OR = 2.1, P = 0.01 for both mothers and young children and odds ratio (OR) = 4.4, P = 0.01 for young children alone). A social network of interpersonal interactions was also derived from the GPS data, and the exposures were positively associated both with the number and duration of peer interaction, suggesting the importance of socio-cultural factors associated with water contact behaviour. The findings illustrate reduction in both prevalence and intensity of infection in this community after treatment as well as remarkably high rates of water contact exposure and re-infection, particularly among younger children. We believe that this should now be formally considered within NCP, which may benefit from more in-depth ethnographic exploration of factors related to water contact as this should provide new opportunities for sustaining control.

  8. [Latent tuberculosis infection and associated risk factors among the tuberculosis contacts in one of district in Shanghai].

    PubMed

    Xie, X; Tang, L H; Huang, X X; Wu, Y; Su, H L

    2016-12-12

    Objective: To investigate the prevalence of latent tuberculosis infection(LTBI) and associated risk factors among the tuberculosis(TB) contacts in Minhang District of Shanghai. Methods: A self-designed questionnaire was used to acquire socio-demographic information and to assess the degree of exposure to index cases. LTBI screening was performed by T-SPOT.TB assay. Pearson chi-square test and Logistic regression analyses were used to identify the risk factors associated with LTBI among the TB contacts. Results: A total of 137 contacts from 59 mycobacterial (culture) positive pulmonary TB patients were enrolled in this study. In these contacts, there were 54 men and 83 women, with the average age of 42. LTBI was identified in 20% (27/137) of these contacts. Several risk factors were found by logistic analyses in this study. The worse the ventilation in the exposure location was, the more likely to develop LTBI. Contacts aged more than 60 (42.1%) were 3.9 times more likely to develop LTBI than those aged less than 60 (16.1%). Individuals in contact with TB patients for more than 40 h/week(25.8%) had a 4.2 times risk of LTBI as compared to those for less than 40 h/week(6.8%). Conclusion: The prevalence of LTBI was 20% among the TB contacts in this study, highlighting the need of TB screening and intervention among TB contacts.

  9. Water graphene contact surface investigated by pairwise potentials from force-matching PAW-PBE with dispersion correction.

    PubMed

    Li, Jicun; Wang, Feng

    2017-02-07

    A pairwise additive atomistic potential was developed for modeling liquid water on graphene. The graphene-water interaction terms were fit to map the PAW-PBE-D3 potential energy surface using the adaptive force matching method. Through condensed phase force matching, the potential developed implicitly considers the many-body effects of water. With this potential, the graphene-water contact angle was determined to be 86° in good agreement with a recent experimental measurement of 85° ± 5° on fully suspended graphene. Furthermore, the PAW-PBE-D3 based model was used to study contact line hysteresis. It was found that the advancing and receding contact angles of water do agree on pristine graphene, however a long simulation time was required to reach the equilibrium contact angle. For water on suspended graphene, sharp peaks in the water density profile disappear when the flexibility of graphene was explicitly considered. The water droplet induces graphene to wrap around it leading to a slightly concave contact interface.

  10. Water films at grain-grain contacts: Debye-Hückel, osmotic model of stress, salinity, and mineralogy dependence

    NASA Astrophysics Data System (ADS)

    Renard, François; Ortoleva, Peter

    1997-05-01

    Water film diffusion is one of the mechanisms proposed to explain the deformation of rocks by pressure-solution during geological processes in the upper crust. This mechanism assumes that matter is dissolved inside the contact between two grains. The resulting solutes are transported in the pore fluid through diffusion in an adsorbed water film. The main problem of this theory is that it requires the presence of a water film that is believed to be stable under large deviatoric stresses inside the contact between two grains. In this paper, we show that the electrically charged surface of a mineral can attract counter-ions from the pore and, by the related change of osmotic pressure, keep water within the contact. This is due to the counter ions in the water film that increase the salinity in the film relative to that in the pore. This lowers the free energy of water in the contact zone to a degree that balances the increase in free energy of water due to the elevated pressure in the film. These notions are made more precise by combining the theory of the Debye-Hückle double layer with equations of osmotic pressure. The resulting D-H/O theory predicts the dependence of the water film thickness on stress across the contact, composition of the pore fluid, and the identity of the minerals involved.

  11. Water graphene contact surface investigated by pairwise potentials from force-matching PAW-PBE with dispersion correction

    NASA Astrophysics Data System (ADS)

    Li, Jicun; Wang, Feng

    2017-02-01

    A pairwise additive atomistic potential was developed for modeling liquid water on graphene. The graphene-water interaction terms were fit to map the PAW-PBE-D3 potential energy surface using the adaptive force matching method. Through condensed phase force matching, the potential developed implicitly considers the many-body effects of water. With this potential, the graphene-water contact angle was determined to be 86° in good agreement with a recent experimental measurement of 85° ± 5° on fully suspended graphene. Furthermore, the PAW-PBE-D3 based model was used to study contact line hysteresis. It was found that the advancing and receding contact angles of water do agree on pristine graphene, however a long simulation time was required to reach the equilibrium contact angle. For water on suspended graphene, sharp peaks in the water density profile disappear when the flexibility of graphene was explicitly considered. The water droplet induces graphene to wrap around it leading to a slightly concave contact interface.

  12. Soil-water contact angle of some soils of the Russian Plane

    NASA Astrophysics Data System (ADS)

    Bykova, Galina; Tyugai, Zemfira; Milanovskiy, Evgeny; Shein, Evgeny

    2016-04-01

    INTRODUCTION Soil wettability affects the aggregate water resistance, the movement of moisture and dissolved substances, preferential flows, etc. There are many factors affecting the soil's wettability (the content of organic matter (OM), soil's mineralogical composition, particle size distribution), so it can reflect changes in the soil, including results of human impact. The quantitative characteristic of soil wettability is a contact angle (CA), its measurement is a new and difficult problem because of the complexity, heterogeneity and polydispersity of the object of investigation. The aim of this work is to study soil-water CA of some soils of the Russian Plane. MATERIALS AND METHODS The objects of study were sod-podzolic (Umbric Albeluvisols Abruptic, Eutric Podzoluvisols), grey forest non-podzolised (Greyic Phaeozems Albic, Haplic Greyzems), typical Chernozems (Voronic Chernozems pachic, Haplic Chernozems) - profiles under the forest and the arable land, and the chestnut (Haplic Kastanozems Chromic, Haplic Kastanozems) soils. The CA's determination was performed by a Drop Shape Analyzer DSA100 by the static sessile drop method. For all samples was determined the content of total and organic carbon (OC and TC) by dry combustion in oxygen flow. RESULTS AND DISCUSSION There is CA increasing from 85,1° (5 cm) to 40-45° (deeper, than 45 cm) in the sod-podzolic soil; OC content is changed at the same depths from 1,44 to 0.22%. We can see the similar picture in profiles of chernozems. In the forest profile the highest OC content and CA value are achieved on the surface of profile (6,41% and 78,1°), and by 90 cm these values are 1.9% and 50.2°. In the chernozem under the arable land the OC content is almost two times less and the profile is more wettable (from 50° to 19° at 5 and 100 cm). Corresponding with the OC content, the curve describing changes of CA in the profile of grey forest soil is S-shaped with peaks at 20 and 150 cm (81,3° and 70° respectively

  13. Immunology and genetics of tumour necrosis factor in allergic contact dermatitis.

    PubMed

    Dittmar, Daan; Schuttelaar, Marie L

    2017-05-01

    During the sensitization phase of allergic contact dermatitis, the proinflammatory cytokine tumour necrosis factor (TNF) plays an important role by promoting epidermal Langerhans cell migration to draining lymph nodes. It also plays a role during the elicitation phase. The TNF gene (TNF) is located within the major histocompatibility complex region. Many single-nucleotide variants exist in the promoter region of TNF, and these may either increase or decrease mRNA transcription and therefore lead to higher or lower levels of TNF. The most extensively studied single-nucleotide variant of TNF is a base pair substitution in the promoter region at location -308 relative to the transcription start site (rs1800629, TNF -308G>A), which is believed to increase transcription and lead to higher TNF levels. The role of TNF in allergic contact dermatitis and the functionality of TNF -308G>A are reviewed in this article. The association between genetic variants and disease can be studied in a case-control design. Only a few case-control studies investigating the association between TNF -308G>A and allergic contact dermatitis have been published, with contradictory results. These are reviewed critically, and suggestions for future case-control studies on this topic are made.

  14. Field evaluation of interfacial and partitioning tracers for characterization of effective NAPL-water contact areas

    SciTech Connect

    Annable, M.D.; Jawitz, J.W.; Rao, P.S.C.; Dai, D.P.; Kim, H.; Wood, A.L.

    1998-05-01

    The use of surface-active tracers for measuring the interfacial area between nonaqueous phase liquids (NAPLs) and water was evaluated in a hydraulically isolated test cell installed in a surficial aquifer located at Hill Air Force Base (AFB), Utah. Interfacial tracers were developed at the University of Florida for quantifying immiscible fluid-fluid interfaces (air-water or NAPL-water) in porous media. Sodium dodecyl benzene sulfonate (SDBS) was used as the interfacial tracer to measure the effective NAPL-water interfacial area (a{sub Nw}), while 2,2-dimethyl-3-pentanol (DMP) was used as the partitioning tracer to estimate the NAPL saturation (S{sub N}). The observed retardation of SDBS and DMP when compared to a nonreactive tracer (bromide or methanol) at eight multi-level sampling locations and one extraction well, was used to quantify the a{sub Nw} and S{sub N} values averaged over the interval between the injection wells and each monitoring point. The NAPL morphology index, defined here as H{sub N} = a{sub Nw}/{psi}S{sub N} ({psi} = porosity), varied significantly within the test cell. In locations where the magnitude of H{sub N} was large, the NAPL was assumed to be more or less uniformly spread, providing good contact with the mobile fluid. In contrast, regions with low H{sub N} values were assumed to have NAPL that was more heterogeneously distributed as isolated patches providing poor contact with the mobile fluid. The index H{sub N}, provided by the combined use of interfacial and partitioning tracers, has important implications for NAPL source region remediation employing in situ flushing technologies.

  15. Risk factors for acanthamoeba keratitis in contact lens users: a case-control study.

    PubMed Central

    Radford, C. F.; Bacon, A. S.; Dart, J. K.; Minassian, D. C.

    1995-01-01

    OBJECTIVE--To investigate reasons for an increase in cases of Acanthamoeba keratitis related to contact lenses. DESIGN--Case-control study. Cases were contact lens related acanthamoeba keratitis patients treated between 1 September 1989 and 31 August 1992. Controls were lens users without lens related disease who presented as new patients to the casualty department from 1 March 1992 to 31 August 1992. All subjects completed a questionnaire detailing lens use and hygiene practices. SETTING--Eye hospital. SUBJECTS--35 cases with acanthamoeba keratitis and 378 controls. MAIN OUTCOME MEASURES--Relative risks comparing different contact lens types, socioeconomic classification, age, sex, lens use, lens wearing experience, hygiene compliance, and hygiene systems. RESULTS--The crude relative risk for developing acanthamoeba keratitis with the use of daily wear disposable lenses was 49.45 (95% confidence interval 6.53 to 2227; P < 0.001) compared with conventional soft lenses (the referent). Multivariable analysis showed that this increased risk could be largely attributed to lack of disinfection (relative risk 55.86 (10 to 302); P < 0.001) and use of chlorine based disinfection (14.63 (2.8 to 76); P = 0.001) compared with other chemical systems (the referent). None of the other outcome measures showed a significant association. CONCLUSIONS--Both failure to disinfect daily wear soft contact lenses and the use of chlorine release lens disinfection systems, which have little protective effect against the organism, are major risk factors for acanthamoeba keratitis. These risks have been particularly common in disposable lens use. Over 80% of acanthamoeba keratitis could be avoided by the use of lens disinfection systems that are effective against the organism. PMID:7787645

  16. Immobilized transition metals stimulate contact activation and drive factor XII-mediated coagulation

    PubMed Central

    Mutch, N.J.; Waters, E.K.; Morrissey, J. H.

    2012-01-01

    Summary Background Upon contact with an appropriate surface, factor XII (FXII) undergoes autoactivation or cleavage by kallikrein. Zn2+ is known to facilitate binding of FXII and the cofactor, high molecular weight kininogen (HK), to anionic surfaces. Objectives To investigate whether transition metals immobilized on liposome surfaces can initiate coagulation via the contact pathway. Methods & Results Liposomes containing a metal ion-chelating lipid (DOGS-NTA) were prepared by membrane extrusion (20% DOGS-NTA, 40% phosphatidylcholine, 10% phosphatidylserine, and 30% phosphatidylethanolamine). Ni2+ immobilized on such liposomes accelerated clotting in normal, but not FXI- or FXII-deficient plasma. Results were comparable to a commercial aPTT reagent. Charging such liposomes with other transition metals revealed differences in their procoagulant capacity, with Ni2+> Cu2+> Co2+ and Zn2+. Plasma could be depleted of FXI, FXII and HK by adsorption with Ni2+-containing beads, resulting in delayed clot times. Consistent with this, FXI, FXII and HK bound to immobilized Ni2+ or Cu2+ with high affinity as determined by surface plasmon resonance. In the presence of Ni2+-bearing liposomes, Km and kcat values derived for autoactivation of FXII and prekallikrein, as well as for activation of FXII by kallikrein or prekallikrein by FXIIa, were similar to literature values in the presence of dextran sulfate. Conclusions Immobilized Ni2+ and Cu2+ bind FXII, FXI and HK with high affinity and stimulate activation of the contact pathway, driving FXII-mediated coagulation. Activation of the contact system by immobilized transition metals may have implications during pathogenic infection or in individuals exposed to high levels of pollution. PMID:22905925

  17. Contact Lens Risks

    MedlinePlus

    ... contact lenses to any water: tap, bottled, distilled, lake or ocean water. Never use non-sterile water ( ... from bacteria in swimming pool water, hot tubs, lakes and the ocean Replace your contact lens storage ...

  18. Origin of the contact angle hysteresis of water on chemisorbed and physisorbed self-assembled monolayers.

    PubMed

    Belman, Nataly; Jin, Kejia; Golan, Yuval; Israelachvili, Jacob N; Pesika, Noshir S

    2012-10-16

    Self-assembled monolayers (SAMs) are known to form on a variety of substrates either via chemisorption (i.e., through chemical interactions such as a covalent bond) or physisorption (i.e., through physical interactions such as van der Waals forces or "ionic" bonds). We have studied the behavior and effects of water on the structures and surface energies of both chemisorbed octadecanethiol and physisorbed octadecylamine SAMs on GaAs using a number of complementary techniques including "dynamic" contact angle measurements (with important time and rate-dependent effects), AFM, and electron microscopy. We conclude that both molecular overturning and submolecular structural changes occur over different time scales when such SAMs are exposed to water. These results provide new insights into the time-dependent interactions between surfaces and colloids functionalized with SAMs when synthesized in or exposed to high humidity or bulk water or wetted by water. The study has implications for a wide array of phenomena and applications such as adhesion, friction/lubrication and wear (tribology), surfactant-solid surface interactions, the organization of surfactant-coated nanoparticles, etc.

  19. Nanometer Contact Physics of Water Ice in Protoplanetary Disks, Breakup, Twisting and Rolling

    NASA Astrophysics Data System (ADS)

    Aumatell, Guillem; Wurm, Gerhard

    2013-07-01

    The formation of planetary bodies is not yet fully understood. Beyond the snow line in protplanetary disks, volatile components like water condense to solid state. The interaction between these solid particles can cause the formation of larger objects due to aggregation at low velocities, or sometimes -depending on the conditions- their own destruction [1,2] . Water ice has been detected in protoplanetary disks [3,4] and in order to understand its role in the formation of icy bodies like icy planets, asteroids and comets, we carried out laboratory experiments. Water ice aggregates have been formed from frozen liquid water droplets at ~ 190 K. Droplets are smaller than 20 μm in radius and show a well defined size distribution. At pressure between 0.1 - 1 mbar and temperatures about 200 K, several effects like sublimation, twisting, rolling and breakup have been observed and measured. By the quantification of parameters like mass, acceleration after breakup and aggregate size and structure, the adhesion force that exist in the contact area between the aggregates' monomers, and other parameters, can be determined

  20. Hepatitis E virus seroprevalence and risk factors for individuals in working contact with animals.

    PubMed

    Chaussade, Hélène; Rigaud, Emma; Allix, Aurore; Carpentier, Audrey; Touzé, Antoine; Delzescaux, Didier; Choutet, Patrick; Garcia-Bonnet, Nathalie; Coursaget, Pierre

    2013-11-01

    In industrial countries genotypes 3 and 4 of HEV are detected in swine, wild boar, deer and rabbits, and they are associated with autochthonous infections suggesting the existence of zoonotic HEV infections, compatible with the putative involvement of undercooked pork and big game products as a source of infection. To evaluate the prevalence of anti-HEV antibodies in different population groups in contact with animals and to investigate risk factors for HEV infection. Serum samples were collected from 859 healthy French subjects, including pig farm workers, forestry workers and individuals without working contact with animals (control group). In addition, 58 swine veterinarians were included in the study. Subjects were interviewed using a structured questionnaire, and anti-HEV antibodies were investigated using a sensitive and specific sandwich ELISA. Anti-Hepatitis E virus (HEV) antibodies were detected in 26% of control population, and in 36% and 44% of forestry and pig farm workers, respectively. In addition, an increase in seroprevalence from the north to the south of France was observed (30.2% versus 40.7%). Consumption of pork liver sausage (AOR 4.4, p < 10(-4)), occupational contact with animals (AOR 1.58, p = 0.038 for forestry workers and AOR 2.51, p < 10(-4) for pig farm workers), and living in southern France (AOR 1.47, p = 0.02), were independent risk factors. Wearing working gloves and boots might reduce HEV infection. Occupational exposure to animals and consuming raw or undercooked pork liver sausage or pork liver play a significant role in HEV transmission in industrial countries. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  1. Risk factors for interruption to soft contact lens wear in children and young adults.

    PubMed

    Wagner, Heidi; Chalmers, Robin L; Mitchell, G Lynn; Jansen, Meredith E; Kinoshita, Beth T; Lam, Dawn Y; McMahon, Timothy T; Richdale, Kathryn; Sorbara, Luigina

    2011-08-01

    The purpose of this study was to describe age and other risk factors for ocular events that interrupt soft contact lens (SCL) wear in youth. A retrospective chart review of SCL wearers aged 8 to 33 years at the first observed visit was conducted at six academic eye care centers in North America. Data were extracted from all visits during the observation period (>3 years). Clinical records that documented conditions resulting in an interruption of SCL wear "events" were scanned, masked for age and SCL parameters, and then adjudicated to consensus diagnosis. Generalized estimating equations were used to examine the effect of selected covariates, including age, on the risk of an event. Chart review of 3549 SCL wearers yielded 522 events among 426 wearers (12%). The risk of an event increased from ages 8 to 18 years, showed modest increases between ages 19 and 25 years, and then began to decline after age 25 years. New lens wearers (<1 year) were less likely to experience events (p = 0.001). Lens replacement schedule and material were also predictive of interruptions to SCL wear with the lowest risk in daily replacement and hydrogel lens wearers (both p < 0.0001). These results suggest that the risk of events that interrupt SCL wear peaks in late adolescence and early adulthood and reflects risk factors identified in prospective contact lens studies. Relative to older teens and young adults, patients younger than 14 years presented with significantly fewer events resulting in interrupted lens wear.

  2. Activation of contact-dependent antibacterial tRNase toxins by translation elongation factors.

    PubMed

    Jones, Allison M; Garza-Sánchez, Fernando; So, Jaime; Hayes, Christopher S; Low, David A

    2017-03-07

    Contact-dependent growth inhibition (CDI) is a mechanism by which bacteria exchange toxins via direct cell-to-cell contact. CDI systems are distributed widely among Gram-negative pathogens and are thought to mediate interstrain competition. Here, we describe tsf mutations that alter the coiled-coil domain of elongation factor Ts (EF-Ts) and confer resistance to the CdiA-CT(EC869) tRNase toxin from enterohemorrhagic Escherichia coli EC869. Although EF-Ts is required for toxicity in vivo, our results indicate that it is dispensable for tRNase activity in vitro. We find that CdiA-CT(EC869) binds to elongation factor Tu (EF-Tu) with high affinity and this interaction is critical for nuclease activity. Moreover, in vitro tRNase activity is GTP-dependent, suggesting that CdiA-CT(EC869) only cleaves tRNA in the context of translationally active GTP·EF-Tu·tRNA ternary complexes. We propose that EF-Ts promotes the formation of GTP·EF-Tu·tRNA ternary complexes, thereby accelerating substrate turnover for rapid depletion of target-cell tRNA.

  3. Quantized Conductance and Large g-Factor Anisotropy in InSb Quantum Point Contacts.

    PubMed

    Qu, Fanming; van Veen, Jasper; de Vries, Folkert K; Beukman, Arjan J A; Wimmer, Michael; Yi, Wei; Kiselev, Andrey A; Nguyen, Binh-Minh; Sokolich, Marko; Manfra, Michael J; Nichele, Fabrizio; Marcus, Charles M; Kouwenhoven, Leo P

    2016-12-14

    Because of a strong spin-orbit interaction and a large Landé g-factor, InSb plays an important role in research on Majorana fermions. To further explore novel properties of Majorana fermions, hybrid devices based on quantum wells are conceived as an alternative approach to nanowires. In this work, we report a pronounced conductance quantization of quantum point contact devices in InSb/InAlSb quantum wells. Using a rotating magnetic field, we observe a large in-plane (|g1| = 26) and out-of-plane (|g1| = 52) g-factor anisotropy. Additionally, we investigate crossings of subbands with opposite spins and extract the electron effective mass from magnetic depopulation of one-dimensional subbands.

  4. Teeth contacting habit as a contributing factor to chronic pain in patients with temporomandibular disorders.

    PubMed

    Sato, Fumiaki; Kino, Koji; Sugisaki, Masashi; Haketa, Tadasu; Amemori, Yoko; Ishikawa, Takayuki; Shibuya, Toshihisa; Amagasa, Teruo; Shibuya, Tomoaki; Tanabe, Haruyasu; Yoda, Tetsuya; Sakamoto, Ichiro; Omura, Ken; Miyaoka, Hitoshi

    2006-06-01

    Many different factors are known to cause and perpetuate the symptoms of temporomandibular disorders (TMD). However, the roles of parafunctional factors have not been clearly elucidated. We found one of these habits in the clinical setting. This parafunctional habit involves daily light touching of the upper and lower teeth, when the mouth is closed. We named this habit Teeth Contacting Habit (TCH). [OBJECTIVES] To investigate the following hypotheses: 1) TCH is associated with perpetuation of chronic pain of TMD patients; 2) TCH is associated with other behavioral factors. [METHODS] Two hundred and twenty-nine TMD outpatients with chronic pain were analyzed with multivariate logistic regression models. [RESULTS] TCH was found in 52.4% of patients. Patients with TCH and pain lasting for more than four months were less likely to experience improvements in pain at the first visit (OR = 1.944, p = 0.043). Other factors associated with TCH were as follows: unilateral chewing (OR = 2.802) and involvement in a precision job (OR = 2.195). [CONCLUSION] TCH can prolong TMD pain and is associated with other behavioral factors.

  5. Recovery of water and acid from leach solutions using direct contact membrane distillation.

    PubMed

    Kesieme, Uchenna K; Milne, Nicholas; Cheng, Chu Yong; Aral, Hal; Duke, Mikel

    2014-01-01

    This paper describes for the first time the use of direct contact membrane distillation (DCMD) for acid and water recovery from a real leach solution generated by a hydrometallurgical plant. The leach solutions considered contained H2SO4 or HCl. In all tests the temperature of the feed solution was kept at 60 °C. The test work showed that fluxes were within the range of 18-33 kg/m(2)/h and 15-35 kg/m(2)/h for the H2SO4 and HCl systems, respectively. In the H2SO4 leach system, the final concentration of free acid in the sample solution increased on the concentrate side of the DCMD system from 1.04 M up to 4.60 M. The sulfate separation efficiency was over 99.9% and overall water recovery exceeded 80%. In the HCl leach system, HCl vapour passed through the membrane from the feed side to the permeate. The concentration of HCl captured in the permeate was about 1.10 M leaving behind only 0.41 M in the feed from the initial concentration of 2.13 M. In all the experiments, salt rejection was >99.9%. DCMD is clearly viable for high recovery of high quality water and concentrated H2SO4 from spent sulfuric acid leach solution where solvent extraction could then be applied to recover the sulfuric acid and metals. While HCl can be recovered for reuse using only DCMD.

  6. In vivo optical investigation of short term skin water contact and moisturizer application using NIR spectroscopy.

    PubMed

    Qassem, M; Kyriacou, P A

    2013-01-01

    Nowadays, a number of noninvasive methods and instruments are available to inspect the biophysical properties and effects of various applicants on human skin, providing quantitative measurements and more details regarding the interactions between skin and various products. Such methods include Near Infrared Spectroscopy (NIRS), a technique which over the years, has gained quite a reputation in being able to accurately determine moisture levels and water contents due to its sensitivity to hydrogen bonding. This paper reports preliminary results of an in vivo study carried out on the skin of a small number of human participants, investigating the optical response of human skin after direct short-term contact with water followed by application of a moisturizer, using a highly advanced spectrophotometer in the region of 900-2100 nm, and equipped with a reflectance fibre optic probe. Results obtained here certainly raise some questions regarding the optical characteristics of different skin types and the influence of frequent moisturizer use, as well as the varying response between different water bands in the NIR region. Future work will focus on gaining more knowledge about these, in order to further improve optical skin measurements, and hopefully support the design and development of a portable and/or miniaturized optical device that could provide reliable, accurate and fast skin hydration readings in real time.

  7. Atrial natriuretic factor and body water distribution.

    PubMed

    Vidal, N A; Arranz, C T; Mones Sias, M C; Herrmann, A P; Martinez Seeber, A

    1987-11-01

    In the rat, the effects of an atrial natriuretic factor (ANF) (Rat, 8-33 Peninsula Lab) on body water distribution have been evaluated. The ANF administration to nephrectomized animals produced a decrease in plasma volume and a slight increase in haematocrit and in plasma albumin concentration. No modifications were observed in total and intracellular water. The fluid efflux from the capillaries appeared to be located in the interstitial space. These results suggest that ANF could regulate plasma volume and systemic blood pressure, concurrently with its other known effects.

  8. Contact Activation of Blood Plasma and Factor XII by Ion-exchange Resins

    PubMed Central

    Yeh, Chyi-Huey Josh; Dimachkie, Ziad O.; Golas, Avantika; Cheng, Alice; Parhi, Purnendu; Vogler, Erwin A.

    2011-01-01

    Sepharose ion-exchange particles bearing strong Lewis acid/base functional groups (sulfopropyl, carboxymethyl, quarternary ammonium, dimethyl aminoethyl, and iminodiacetic acid) exhibiting high plasma protein adsorbent capacities are shown to be more efficient activators of blood factor XII in neat-buffer solution than either hydrophilic clean-glass particles or hydrophobic octyl sepharose particles ( FXII→surfaceactivatorFXIIa; a.k.a autoactivation, where FXII is the zymogen and FXIIa is a procoagulant protease). In sharp contrast to the clean-glass standard of comparison, ion-exchange activators are shown to be inefficient activators of blood plasma coagulation. These contrasting activation properties are proposed to be due to the moderating effect of plasma-protein adsorption on plasma coagulation. Efficient adsorption of blood plasma proteins unrelated to the coagulation cascade impedes FXII contacts with ion-exchange particles immersed in plasma, reducing autoactivation, and causing sluggish plasma coagulation. By contrast, plasma proteins do not adsorb to hydrophilic clean glass and efficient autoactivation leads directly to efficient activation of plasma coagulation. It is also shown that competitive-protein adsorption can displace FXIIa adsorbed to the surface of ion-exchange resins. As a consequence of highly-efficient autoactivation and FXIIa displacement by plasma proteins, ion-exchange particles are slightly more efficient activators of plasma coagulation than hydrophobic octyl sepharose particles that do not bear strong Lewis acid/base surface functionalities but to which plasma proteins adsorb efficiently. Plasma proteins thus play a dual role in moderating contact activation of the plasma coagulation cascade. The principal role is impeding FXII contact with activating surfaces but this same effect can displace FXIIa from an activating surface into solution where the protease can potentiate subsequent steps of the plasma coagulation cascade. PMID

  9. Effects of water-vapor on friction and deformation of polymeric magnetic media in contact with a ceramic oxide

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1984-01-01

    The effects of humidity (water-vapor) in nitrogen on the friction and deformation behavior of magnetic tape in contact with a Ni-Zn ferrite spherical pin were studied. The coefficient of friction is markedly dependent on the ambient relative humidity. In elastic contacts the coefficient of friction increased linearly with increasing humidity; it decreased linearly when humidity was lowered. This effect is the result of changes in the chemistry and interaction of tape materials such as degradation of the lubricant. In plastic contacts there was no effect of humidity on friction below 40 percent relative humidity. There is no effect on friction associated with the breakthrough of the adsorbed water-vapor film at the interface of the tape and Ni-Zn ferrite. The coefficient of friction, however, increased rapidly with increasing relative humidity above 40 percent in plastic contacts.

  10. Estimating drinking-water ingestion and dermal contact with water in a French population of pregnant women: the EDDS cohort study.

    PubMed

    Albouy-Llaty, Marion; Dupuis, Antoine; Grignon, Claire; Strezlec, Sylvie; Pierre, Fabrice; Rabouan, Sylvie; Migeot, Virginie

    2015-05-01

    The aim of the present study, a part of the Endocrine Disruptor Deux-Sèvres (EDDS) cohort study, was to estimate water-use habits of pregnant French women. The study population consisted of 132 pregnant women living in Deux-Sèvres (France) in 2012-2013, in areas where drinking water is exclusively produced by surface water. Drinking-water data included ingested water (tap, bottled and filtered) and ingestion place (home, work and elsewhere). Dermal contact with water included showering, bathing, swimming, spa use, hand-washing and other water activities. Data were collected through face-to-face interviews at second and third trimesters of pregnancy with a 1-day-recall questionnaire. Intertrimestral differences in water-use habits were assessed. Predictors of water ingestion and duration of dermal contact with water were assessed with multiple linear regressions. At the second trimester of pregnancy, the mean total drinking-water ingestion was 1.8±0.6 l per day (mean and SD), 71% of which was tap water. Total drinking-water ingestion was not different between both trimesters but ingestion place differed. Dermal contact with water estimate was 188±118 and 173±92 min/week at second and third trimesters, respectively. Smoking increased water ingestion 777 ml/day 95% CI (171-1384). Duration of dermal contact in spring was 30 min/week 95% CI (13-48) higher than in winter. Obese women spend 26 min/week 95% CI (2-50) more showering than women with recommended weight. Our estimates of pregnant French women's exposure to water will help researchers to better assess water pollutant risks.

  11. Use of Atomic Oxygen for Increased Water Contact Angles of Various Polymers for Biomedical Applications

    NASA Technical Reports Server (NTRS)

    deGroh, Kim; Berger, Lauren; Roberts, Lily

    2009-01-01

    The purpose of this study was to determine the effect of atomic oxygen (AO) exposure on the hydrophilicity of nine different polymers for biomedical applications. Atomic oxygen treatment can alter the chemistry and morphology of polymer surfaces, which may increase the adhesion and spreading of cells on Petri dishes and enhance implant growth. Therefore, nine different polymers were exposed to atomic oxygen and water-contact angle, or hydrophilicity, was measured after exposure. To determine whether hydrophilicity remains static after initial atomic oxygen exposure, or changes with higher fluence exposures, the contact angles between the polymer and water droplet placed on the polymer s surface were measured versus AO fluence. The polymers were exposed to atomic oxygen in a 100-W, 13.56-MHz radio frequency (RF) plasma asher, and the treatment was found to significantly alter the hydrophilicity of non-fluorinated polymers. Pristine samples were compared with samples that had been exposed to AO at various fluence levels. Minimum and maximum fluences for the ashing trials were set based on the effective AO erosion of a Kapton witness coupon in the asher. The time intervals for ashing were determined by finding the logarithmic values of the minimum and maximum fluences. The difference of these two values was divided by the desired number of intervals (ideally 10). The initial desired fluence was then multiplied by this result (2.37), as was each subsequent desired fluence. The flux in the asher was determined to be approximately 3.0 x 10(exp 15) atoms/sq cm/sec, and each polymer was exposed to a maximum fluence of 5.16 x 10(exp 20) atoms/sq cm.

  12. Fabrication of a silica aerogel and examination of its hydrophobic properties via contact angle and 3M water repellency tests

    NASA Astrophysics Data System (ADS)

    Mazrouei-Sebdani, Z.; Javazmi, L.; Khoddami, A.; Shams-Ghahfarokhi, F.; Low, T.

    2017-05-01

    Aerogels are dry gels with a very high specific pore volume. Aerogels with increased hydrophobicity have significant potential to expand their use as lightweight materials. Considering its special nanostructure and exceptional properties, this paper focuses on the synthesis and hydrophobic evaluation of a silica aerogel. The structural properties were investigated by measuring density, SEM micrographs, and BET analyses. Also, the hydrophobic evaluation was carried out by measuring 3M water repellency and water/alcohol contact angle. The BET analysis showed successful synthesis of the nanoporous silica aerogel with a pore size of 24 nm and porosity of 89%. The synthesized aerogel showed 3M water repellency of 3 and water contact angle of 129.6°. Also, it is worth-mentioning that as the alcohol content of the drops in 3M water repellency test is increased, the drop contact angle is decreased due to its lower surface tension. Thus, the contact angle reaches the zero at 3M water repellency test number of 4 (water/alcohol 60/40).

  13. Molecular structure of an alkyl-side-chain polymer-water interface: origins of contact angle hysteresis.

    PubMed

    Rangwalla, Hasnain; Schwab, Alexander D; Yurdumakan, Betül; Yablon, Dalia G; Yeganeh, Mohsen S; Dhinojwala, Ali

    2004-09-28

    A new and direct approach to verify surface heterogeneity as the microscopic origin of contact-angle hysteresis is demonstrated. IR-visible sum-frequency-generation spectroscopy (SFG) was used to selectively probe the molecules at the interface of an alkyl-side-chain polymer [poly(vinyl n-octadecyl carbamate-co-vinyl acetate)] with water. The spectra indicate that in contact with water, the polymer surface is heterogeneous (having areas of differing surface energies). This evidence of surface heterogeneity supports the hysteresis observed in the advancing and receding contact angles of the polymer surface with water. The same measurements made for the chemically and structurally similar surface of an octadecyltrichlorosilane self-assembled monolayer indicates a homogeneous surface at the water interface. In this case, contact-angle hysteresis measurements implicate surface roughness as the cause of hysteresis. Atomic force microscopy measurements of roughness for these surfaces further support our conclusions. The polymer-water interface was probed using SFG at above-ambient temperatures, and an order-to-disorder transition (ODT) of alkyl side chains at the interface was observed, which closely follows the melting of crystalline side chains in the bulk. This transition explains the increased wettability of the polymer, by water, when the temperature is raised above the bulk melting temperature. Furthermore, the irreversibility of this ODT suggests that the disordered polymer-water interface is the thermodynamic equilibrium state, whereas the before-heating structure of this interface is a kinetically hindered metastable state.

  14. Acanthamoeba spp. in domestic tap water in houses of contact lens wearers in the metropolitan area of Mexico City.

    PubMed

    Bonilla-Lemus, Patricia; Ramírez-Bautista, Gerardo A; Zamora-Muñoz, Claudia; Ibarra-Montes, María Del Rocío; Ramírez-Flores, Elizabeth; Hernández-Martínez, María Dolores

    2010-09-01

    A survey was carried out in the metropolitan area of Mexico City to determine the presence of Acanthamoeba in the tap water of houses of contact lens wearers. Water samples were taken from the mains water entry, bathroom sinks and storage containers (roof tanks, cisterns) of 27 houses; and from the solution contained in the contact lens cases. Samples were filtered and cultured onto NNE medium. The isolates were identified based on their morphological features and pathogenicity. Total and fecal coliforms, water temperature, pH, dissolved oxygen and residual free-chlorine were measured by standard methods. Forty five isolates of Acanthamoeba from 200 water samples were obtained. The highest number of amoebae was isolated from cisterns and roof tanks. Most Acanthamoeba isolates were non-pathogenic, however, their presence in tap water is a potential hazard since some species can cause Acanthamoeba keratitis and granulomatous amoebic encephalitis. Copyright 2010 Elsevier Inc. All rights reserved.

  15. ηc elastic and transition form factors: Contact interaction and algebraic model

    NASA Astrophysics Data System (ADS)

    Bedolla, Marco A.; Raya, Khépani; Cobos-Martínez, J. J.; Bashir, Adnan

    2016-05-01

    For the flavor-singlet heavy-quark system of charmonia in the pseudoscalar [ηc(1 S ) ] channel, we calculate the elastic (EFF) and transition form factors (TFFs) [ηc(1 S )→γ γ* ] for a wide range of photon momentum transfer squared (Q2). The framework for this analysis is provided by a symmetry-preserving Schwinger-Dyson equation and Bethe-Salpeter equation treatment of a vector×vector contact interaction. We also employ an algebraic model, developed earlier to describe the light-quark systems. It correctly correlates infrared and ultraviolet dynamics of quantum chromodynamics (QCD). The contact interaction results agree with the lattice data for low Q2. For Q2≥Q02 , the results start deviating from the lattice results by more than 20%. Q02≈2.5 GeV2 for the EFF, and ≈25 GeV2 for the TFF. We also present the results for the EFF, TFF, and ηc(1 S ) parton distribution amplitude for the algebraic model. Wherever the comparison is possible, these results are in excellent agreement with the lattice, perturbative QCD, results obtained through a Schwinger-Dyson equation-Bethe-Salpeter equation study, employing refined truncations, and the experimental findings of the BABAR experiment.

  16. Prevalence and risk factors of contact dermatitis among clothing manufacturing employees in Beijing

    PubMed Central

    Chen, Yu-Xin; Cheng, Hai-Yan; Li, Lin-Feng

    2017-01-01

    Abstract Little is known about the epidemiology of contact dermatitis (CD) in the Chinese clothing industry. This study aimed to investigate the prevalence and some risk factors of contact dermatitis among clothing manufacturing employees in Beijing. This cross-sectional study was conducted by interview using self-administered questionnaires and skin examination between May and August in 2016. Five-hundred twenty-nine employees who had worked at sewing, ironing, and as managers at 12 clothing manufacturing factories were studied. The overall 1-year prevalence of CD among the clothing employees was 28.5% (151/529 employees), with significantly higher prevalence among ironing workers (50%) and sewers (31.7%) compared with managers (12.7%; P < 0.001, n = 529). A significant association was noticed between the 1-year prevalence of CD and types of occupation (sewers and ironing workers versus managers, respectively), exposure to garment materials (leather and feather), dry skin, allergic rhinitis, age, and smoking. Among employees in Chinese clothing industry, sewers and ironing workers had a higher 1-year prevalence of CD than managers. It is noteworthy that exposure to leather and feather materials and the types of manual work are associated with CD, as well as dry skin and allergic rhinitis. PMID:28328819

  17. In vitro water wettability of silicone hydrogel contact lenses determined using the sessile drop and captive bubble techniques.

    PubMed

    Maldonado-Codina, Carole; Morgan, Philip B

    2007-11-01

    This study investigated the water contact angles of five commercially available silicone hydrogel contact lenses (Acuvue Advance, Acuvue Oasys, Focus Night & Day, O2 Optix, and PureVision) using sessile drop and captive bubble techniques. The only lens type that showed a significant difference in water contact angle when measured by sessile drop direct from the blister compared with after 48 h of soaking/washing in saline was the Acuvue Advance lens (from 66 degrees to 96 degrees, respectively) (p=0.0002), presumably because of surface active agents within the blister solution. The water contact angle data split the lenses into two distinct groups (pContact angle analysis of hydrogel lens surfaces is highly methodologically dependent and may be able to predict the clinical performance of contact lenses in vivo. Copyright (c) 2007 Wiley Periodicals, Inc.

  18. Characterization of a dielectric barrier discharge in contact with liquid and producing a plasma activated water

    NASA Astrophysics Data System (ADS)

    Neretti, G.; Taglioli, M.; Colonna, G.; Borghi, C. A.

    2017-01-01

    In this work a low-temperature plasma source for the generation of plasma activated water (PAW) is developed and characterized. The plasma reactor was operated by means of an atmospheric-pressure air dielectric barrier discharge (DBD). The plasma generated is in contact with the water surface and is able to chemically activate the liquid medium. Electrodes were supplied by both sinusoidal and nanosecond-pulsed voltage waveforms. Treatment times were varied from 2 to 12 min to increase the energy dose released to the water by the DBD plasma. The physics of the discharge was studied by means of electrical, spectroscopic and imaging diagnostics. The interaction between the plasma and the liquid was investigated as well. Temperature and composition of the treated water were detected. Images of the discharges showed a filamentary behaviour in the sinusoidal case and a more homogeneous behaviour in the nanosecond-pulsed one. The images and the electrical measurements allowed to evaluate an average electron number density of about 4  ×  1019 and 6  ×  1017 m-3 for the sinusoidal and nanosecond-pulsed discharges respectively. Electron temperatures in the range of 2.1÷2.6 eV were measured by using spectroscopic diagnostics. Rotational temperatures in the range of 318-475 K were estimated by fitting synthetic spectra with the measured ones. Water temperature and pH level did not change significantly after the exposure to the DBD plasma. The production of ozone and hydrogen peroxide within the water was enhanced by increasing the plasma treatment time and the energy dose. Numerical simulations of the nanosecond-pulsed discharge were performed by using a self-consistent coupling of state-to-state kinetics of the air mixture with the Boltzmann equation of free electron kinetics. Temporal evolution of the electron energy distribution function shows departure from the Maxwellian distribution especially during the afterglow phase of the discharge. When

  19. Mechanisms for Strong Anisotropy of In-Plane g -Factors in Hole Based Quantum Point Contacts

    NASA Astrophysics Data System (ADS)

    Miserev, D. S.; Srinivasan, A.; Tkachenko, O. A.; Tkachenko, V. A.; Farrer, I.; Ritchie, D. A.; Hamilton, A. R.; Sushkov, O. P.

    2017-09-01

    In-plane hole g factors measured in quantum point contacts based on p -type heterostructures strongly depend on the orientation of the magnetic field with respect to the electric current. This effect, first reported a decade ago and confirmed in a number of publications, has remained an open problem. In this work, we present systematic experimental studies to disentangle different mechanisms contributing to the effect and develop the theory which describes it successfully. We show that there is a new mechanism for the anisotropy related to the existence of an additional B+k-4σ+ effective Zeeman interaction for holes, which is kinematically different from the standard single Zeeman term B-k-2σ+ considered until now.

  20. Short-term organic carbon migration from polymeric materials in contact with chlorinated drinking water.

    PubMed

    Mao, Guannan; Wang, Yingying; Hammes, Frederik

    2017-09-24

    Polymeric materials are widely used in drinking water distribution systems. These materials could release organic carbon that supports bacterial growth. To date, the available migration assays for polymeric materials have not included the potential influence of chlorination on organic carbon migration behavior. Hence, we established a migration and growth potential protocol specifically for analysis of carbon migration from materials in contact with chlorinated drinking water. Four different materials were tested, including ethylene propylene dienemethylene (EPDM), poly-ethylene (PEX b and PEX c) and poly-butylene (PB). Chlorine consumption rates decreased gradually over time for EPDM, PEXc and PB. In contrast, no free chlorine was detected for PEXb at any time during the 7 migration cycles. Total organic carbon (TOC) and assimilable organic carbon (AOC) was evaluated in both chlorinated and non-chlorinated migrations. TOC concentrations for EPDM and PEXb in chlorinated migrations were significantly higher than non-chlorinated migrations. The AOC results showed pronounced differences among tested materials. AOC concentrations from chlorinated migration waters of EPDM and PB were higher compared to non-chlorinated migrations, whereas the opposite trend was observed for PEXb and PEXc. There was also a considerable difference between tested materials with regards to bacterial growth potential. The results revealed that the materials exposed to chlorine-influenced migration still exhibited a strong biofilm formation potential. The overall results suggested that the choice in material would make a considerable difference in chlorine consumption and carbon migration behavior in drinking water distribution systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Factor XI Deficiency Alters the Cytokine Response and Activation of Contact Proteases during Polymicrobial Sepsis in Mice.

    PubMed

    Bane, Charles E; Ivanov, Ivan; Matafonov, Anton; Boyd, Kelli L; Cheng, Qiufang; Sherwood, Edward R; Tucker, Erik I; Smiley, Stephen T; McCarty, Owen J T; Gruber, Andras; Gailani, David

    2016-01-01

    Sepsis, a systemic inflammatory response to infection, is often accompanied by abnormalities of blood coagulation. Prior work with a mouse model of sepsis induced by cecal ligation and puncture (CLP) suggested that the protease factor XIa contributed to disseminated intravascular coagulation (DIC) and to the cytokine response during sepsis. We investigated the importance of factor XI to cytokine and coagulation responses during the first 24 hours after CLP. Compared to wild type littermates, factor XI-deficient (FXI-/-) mice had a survival advantage after CLP, with smaller increases in plasma levels of TNF-α and IL-10 and delayed IL-1β and IL-6 responses. Plasma levels of serum amyloid P, an acute phase protein, were increased in wild type mice 24 hours post-CLP, but not in FXI-/- mice, supporting the impression of a reduced inflammatory response in the absence of factor XI. Surprisingly, there was little evidence of DIC in mice of either genotype. Plasma levels of the contact factors factor XII and prekallikrein were reduced in WT mice after CLP, consistent with induction of contact activation. However, factor XII and PK levels were not reduced in FXI-/- animals, indicating factor XI deficiency blunted contact activation. Intravenous infusion of polyphosphate into WT mice also induced changes in factor XII, but had much less effect in FXI deficient mice. In vitro analysis revealed that factor XIa activates factor XII, and that this reaction is enhanced by polyanions such polyphosphate and nucleic acids. These data suggest that factor XI deficiency confers a survival advantage in the CLP sepsis model by altering the cytokine response to infection and blunting activation of the contact (kallikrein-kinin) system. The findings support the hypothesis that factor XI functions as a bidirectional interface between contact activation and thrombin generation, allowing the two processes to influence each other.

  2. Solid-Contact pH Sensor without CO2 Interference with a Superhydrophobic PEDOT-C14 as Solid Contact: The Ultimate "Water Layer" Test.

    PubMed

    Guzinski, Marcin; Jarvis, Jennifer M; D'Orazio, Paul; Izadyar, Anahita; Pendley, Bradford D; Lindner, Ernő

    2017-08-15

    The aim of this study was to find a conducting polymer-based solid contact (SC) for ion-selective electrodes (ISEs) that could become the ultimate, generally applicable SC, which in combination with all kinds of ion-selective membranes (ISMs) would match the performance characteristics of conventional ISEs. We present data collected with electrodes utilizing PEDOT-C14, a highly hydrophobic derivative of poly(3,4-ethylenedioxythiophene), PEDOT, as SC and compare its performance characteristics with PEDOT-based SC ISEs. PEDOT-C14 has not been used in SC ISEs previously. The PEDOT-C14-based solid contact (SC) ion-selective electrodes (ISEs) (H(+), K(+), and Na(+)) have outstanding performance characteristics (theoretical response slope, short equilibration time, excellent potential stability, etc.). Most importantly, PEDOT-C14-based SC pH sensors have no CO2 interference, an essential pH sensors property when aimed for whole-blood analysis. The superhydrophobic properties (water contact angle: 136 ± 5°) of the PEDOT-C14 SC prevent the detachment of the ion-selective membrane (ISM) from its SC and the accumulation of an aqueous film between the ISM and the SC. The accumulation of an aqueous film between the ISM and its SC has a detrimental effect on the sensor performance. Although there is a test for the presence of an undesirable water layer, if the conditions for this test are not selected properly, it does not provide an unambiguous answer. On the other hand, recording the potential drifts of SC electrodes with pH-sensitive membranes in samples with different CO2 levels can effectively prove the presence or absence of a water layer in a short time period.

  3. The impact of educational videotapes on water contact behaviour of primary school students in the Dongting Lakes region, China.

    PubMed

    Yuan, L; Manderson, L; Tempongko, M S; Wei, W; Aiguo, P

    2000-08-01

    Multimedia has become increasingly important in educational programmes in schools in all societies, and has potential value for health education. We developed a video and a comic book on the transmission and prevention of schistosomiasis for use in primary schools in endemic areas of China. The material was designed to increase children's knowledge of schistosomiasis as an environmental disease and to encourage them to reduce their contact with unsafe water sources. To test the effectiveness of the video and booklet, a quasi-experimental study was conducted among 1,739 children in 50 primary schools in the Dongting Lake region. A self-administered questionnaire pre- and post-intervention showed a significant increase in knowledge about schistosomiasis in the intervention schools. Significantly, this change was associated with a decrease in contact with unsafe water sources, as established from water contact observations. This behavioural change suggests the value of short, targeted educational interventions to decrease risk of infection.

  4. Hazards of Healthy Living: Bottled Water and Salad Vegetables as Risk Factors for Campylobacter Infection

    PubMed Central

    Ribeiro, C. Donald; Salmon, Roland L.

    2003-01-01

    Campylobacter is the most common cause of bacterial gastroenteritis worldwide, yet the etiology of this infection remains only partly explained. In a retrospective cohort study, we compared 213 sporadic campylobacter case-patients with 1,144 patients with negative fecal samples. Information was obtained on food history, animal contact, foreign travel, leisure activities, medical conditions, and medication use. Eating chicken, eating food from a fried chicken outlet, eating salad vegetables, drinking bottled water, and direct contact with cows or calves were all independently associated with infection. The population-attributable fractions for these risk factors explained nearly 70% of sporadic campylobacter infections. Eating chicken is a well-established risk factor, but consuming salad and bottled water are not. The association with salad may be explained by cross-contamination of food within the home, but the possibility that natural mineral water is a risk factor for campylobacter infection could have wide public health implications. PMID:14609455

  5. Risk Factors for Contact Lens-Related Microbial Keratitis: A Case-Control Multicenter Study.

    PubMed

    Sauer, Arnaud; Meyer, Nicolas; Bourcier, Tristan

    2016-05-01

    The most feared complication of contact lens (CL) wear is microbial keratitis (MK), even though its incidence remains low. This study aimed to identify the risk factors of CL-related MK in a large, prospective, multicenter case-control study. A multicenter case-control study was designed. The CL-related MK subpopulation (Case) was compared with healthy CL wearers (Control) using a 52-item anonymous questionnaire designed to determine subject demographics and lens wear history. Univariate and multivariate logistic regression analyses were performed to compare both groups. The study enrolled 499 cases and 508 controls. The risk factors associated with the greatest increased odds of CL-related MK were as follows: using disinfecting solution more than 3 months (odds ratio [OR]=1.94), cosmetic CL wear and use of multipurpose disinfection solution (1.37 each), overnight wear, and soft lens use (OR=1.24 each). The protective factors associated with the greatest reduction in OR were fitting by an ophthalmologist (OR=0.73) and hyperopia versus myopia (OR=0.75). The infectious determinants were linked to the type of lenses, hygiene routine, CL handling, disinfecting solution, and storage case. This study aimed to highlight the increasingly CL-related MK, which likely occurs because of lack of patient information regarding basic rules of hygiene and CL care and handling.

  6. Destruction of 4-phenolsulfonic acid in water by anodic contact glow discharge electrolysis.

    PubMed

    Yang, Haiming; An, Baigang; Wang, Shaoyan; Li, Lixiang; Jin, Wenjie; Li, Lihua

    2013-06-01

    Destruction of 4-phenolsulfonic acid (4-PSA) in water was carried out using anodic contact glow discharge electrolysis. Accompanying the decay of 4-PSA, the amount of total organic carbon (TOC) in water correspondingly decreased, while the sulfonate group of 4-PSA was released as sulfate ion. Oxalate and formate were obtained as minor by-products. Additionally, phenol, 1,4-hydroquinone, hydroxyquinol and 1,4-benzoquinone were detected as primary intermediates in the initial stages of decomposition of 4-PSA. A reaction pathway involving successive attacks of hydroxyl and hydrogen radicals was assumed on the basis of the observed products and kinetics. It was revealed that the decay of both 4-PSA and TOC obeyed a first-order rate law. The effects of different Fe ions and initial concentrations of 4-PSA on the degradation rate were investigated. It was found that the presence of Fe ions could increase the degradation rate of 4-PSA, while initial concentrations lower than 80 mmol/L had no significant effect on kinetic behaviour. The disappearance rate of 4-PSA was significantly affected by pH.

  7. Computational prediction of octanol-water partition coefficient based on the extended solvent-contact model.

    PubMed

    Kim, Taeho; Park, Hwangseo

    2015-07-01

    The logarithm of 1-octanol/water partition coefficient (LogP) is one of the most important molecular design parameters in drug discovery. Assuming that LogP can be calculated from the difference between the solvation free energy of a molecule in water and that in 1-octanol, we propose a method for predicting the molecular LogP values based on the extended solvent-contact model. To obtain the molecular solvation free energy data for the two solvents, a proper potential energy function was defined for each solvent with respect to atomic distributions and three kinds of atomic parameters. Total 205 atomic parameters were optimized with the standard genetic algorithm using the training set consisting of 139 organic molecules with varying shapes and functional groups. The LogP values estimated with the two optimized solvation free energy functions compared reasonably well with the experimental results with the associated squared correlation coefficient and root mean square error of 0.824 and 0.697, respectively. Besides the prediction accuracy, the present method has the merit in practical applications because molecular LogP values can be computed straightforwardly from the simple potential energy functions without the need to calculate various molecular descriptors. The methods for enhancing the accuracy of the present prediction model are also discussed.

  8. Transmission of Infectious Vibrio cholerae through Drinking Water among the Household Contacts of Cholera Patients (CHoBI7 Trial)

    PubMed Central

    Rafique, Raisa; Rashid, Mahamud-ur; Monira, Shirajum; Rahman, Zillur; Mahmud, Md. Toslim; Mustafiz, Munshi; Saif-Ur-Rahman, K. M.; Johura, Fatema-Tuz; Islam, Saiful; Parvin, Tahmina; Bhuyian, Md. Sazzadul I.; Sharif, Mohsena B.; Rahman, Sabita R.; Sack, David A.; Sack, R. Bradley; George, Christine M.; Alam, Munirul

    2016-01-01

    Recurrent cholera causes significant morbidity and mortality among the growing population of Dhaka, the capital city of Bangladesh. Previous studies have demonstrated that household contacts of cholera patients are at >100 times higher risk of cholera during the week after the presentation of the index patient. Our prospective study investigated the mode of transmission of Vibrio cholerae, the cause of cholera, in the households of cholera patients in Dhaka city. Out of the total 420 rectal swab samples analyzed from 84 household contacts and 330 water samples collected from 33 households, V. cholerae was isolated from 20%(17/84) of household contacts, 18%(6/33) of stored drinking water, and 27%(9/33) of source water samples. Phenotypic and molecular analyses results confirmed the V. cholerae isolates to be toxigenic and belonging to serogroup O1 biotype El Tor (ET) possessing cholera toxin of classical biotype (altered ET). Phylogenetic analysis by pulsed-field gel electrophoresis (PFGE) showed the V. cholerae isolates to be clonally linked, as >95% similarity was confirmed by sub-clustering patterns in the PFGE (NotI)-based dendrogram. Mapping results showed cholera patients to be widely distributed across 25 police stations. The data suggesting the transmission of infectious V. cholerae within the household contacts of cholera patients through drinking water underscores the need for safe water to prevent spread of cholera and related deaths in Dhaka city. PMID:27803695

  9. Transmission of Infectious Vibrio cholerae through Drinking Water among the Household Contacts of Cholera Patients (CHoBI7 Trial).

    PubMed

    Rafique, Raisa; Rashid, Mahamud-Ur; Monira, Shirajum; Rahman, Zillur; Mahmud, Md Toslim; Mustafiz, Munshi; Saif-Ur-Rahman, K M; Johura, Fatema-Tuz; Islam, Saiful; Parvin, Tahmina; Bhuyian, Md Sazzadul I; Sharif, Mohsena B; Rahman, Sabita R; Sack, David A; Sack, R Bradley; George, Christine M; Alam, Munirul

    2016-01-01

    Recurrent cholera causes significant morbidity and mortality among the growing population of Dhaka, the capital city of Bangladesh. Previous studies have demonstrated that household contacts of cholera patients are at >100 times higher risk of cholera during the week after the presentation of the index patient. Our prospective study investigated the mode of transmission of Vibrio cholerae, the cause of cholera, in the households of cholera patients in Dhaka city. Out of the total 420 rectal swab samples analyzed from 84 household contacts and 330 water samples collected from 33 households, V. cholerae was isolated from 20%(17/84) of household contacts, 18%(6/33) of stored drinking water, and 27%(9/33) of source water samples. Phenotypic and molecular analyses results confirmed the V. cholerae isolates to be toxigenic and belonging to serogroup O1 biotype El Tor (ET) possessing cholera toxin of classical biotype (altered ET). Phylogenetic analysis by pulsed-field gel electrophoresis (PFGE) showed the V. cholerae isolates to be clonally linked, as >95% similarity was confirmed by sub-clustering patterns in the PFGE (NotI)-based dendrogram. Mapping results showed cholera patients to be widely distributed across 25 police stations. The data suggesting the transmission of infectious V. cholerae within the household contacts of cholera patients through drinking water underscores the need for safe water to prevent spread of cholera and related deaths in Dhaka city.

  10. [Elaboration of the method for assessment of susceptibility to microbial growth of materials contacting with drinking water].

    PubMed

    Szczotko, Maciej; Krogulska, Bozena; Krogulski, Adam

    2008-01-01

    Initial methodological study was conducted to determine the susceptibility to microbial growth of different materials applied in contact with drinking water. The purpose of this assay was to elaborate the method for determining the ability of different materials contacting with drinking water to promote microbial growth and to determine possible correlation of results obtained by two analytic methods: inoculation of microorganisms swabbed from materials surface into a medium and ATP level examination. The assay was conducted during 16 weeks in dynamic conditions using continuous flow reactor. Every two weeks swabbes from examinated materials were collected and the total number of microorganisms was determined after incubation in 22 degrees C for 72 hours and in 37 degrees C for 48 hours respectively. Determination of microorganisms number and ATP level were both examinated in water inlet. Difference in susceptibility to microbial growth of different materials used in contact with drinking water was observed. This was confirmed by both analytic methods. Microbial growth on the surface of negative control materials (glass, poliethylene and stainless steel) was several time less intensive than on positive control material (floor finish not destined for contact with drinking water). Correlation between the quantity of microorganisms and ATP level on the surface of the same kind of materials was confirmed. Usefulness of continous flow reactor was confirmed.

  11. Factors associated with seropositivity for APGL-Iamong household contacts of leprosy patients.

    PubMed

    Wambier, Carlos Gustavo; Wambier, Sarah Perillo de Farias; Furini, Renata Bazan; Simão, João Carlos Lopes; Frade, Marco Andrey Cipriani; Foss, Norma Tiraboschi

    2016-02-01

    Leprosy is mainly transmitted among family members who share genetic and ambient factors. The clinical form of leprosy in the index case and kinship could be risk factors for leprosy transmission. High antibody levels in household contacts (HC) in the absence of neural or skin lesions may characterize latent infection. This study aimed to evaluate the association between seropositivity for anti-phenolic glycolipid-I immunoglobulin M antibodies (APGL-I) in HC and the clinical classification of the index case and to analyze the association between APGL-I positivity with other factors such as age, kinship, and gender. We performed a survey among 320 HC of 120 leprosy patients who were evaluated and followed-up in a leprosy outpatient clinic of a university hospital. All HC underwent complete skin examination, peripheral nerve palpation, skin sensory tests, and serologic tests for the detection and quantification of APGL-I. The overall seropositivity rate was 20%, and was greatly affected by kinship. APGL-I seropositivity was higher in siblings (41%), followed by parents (28%), spouses (26%), other (19%), and offspring (14%). Independent risk factors for seropositivity were being siblings (OR 3.3) and being a HC of an index case with indeterminate leprosy (OR 5.3). APGL-I seropositivity was associated with index cases with a bacillary index of 4 (88%; p<.001). Seropositivity among HC was not significantly associated with their gender and age. There was no statistical difference in the seropositivity rates of HC of index patients with paucibacillary and multibacillary leprosy. Strict evaluation and follow-up of HC with positive results for APGL-I is recommended. Special attention should be paid during the screening of siblings of the index cases, HC of patients with a high bacillary index, and HC of patients with indeterminate leprosy.

  12. Risk factors for acquisition of OXA-48-producing Klebsiella pneumonia among contact patients: a multicentre study.

    PubMed

    Hilliquin, D; Le Guern, R; Thepot Seegers, V; Neulier, C; Lomont, A; Marie, V; Legeay, C; Merrer, J; Lepelletier, D; Rogues, A M; Grandbastien, B; Lucet, J C; Zahar, J R

    2017-09-04

    Cohorting carbapenemase-producing Enterobacteriaceae (CPE) carriers during hospitalization limits in-hospital spreading. To identify risk factors for CPE acquisition among contacts of an index patient in non-cohorted populations. A multicentre retrospective matched case-control study was conducted in five hospitals. Each contact patient (case) who acquired Klebsiella pneumoniae (KP)-OXA-48 from an index patient was compared to three contact (controls) with the same index patients matched with hospitalization in the same unit and similar exposure times. Fifty-one secondary cases and 131 controls were included. By univariate analysis, exposure time (odds ratio: 1.06; 95% confidence interval: 1.02-1.1; P = 0.006), concomitant infection at admission (3.23; 1.42-7.35; P = 0.005), antimicrobial therapy within the last month before hospitalization (2.88; 1.34-6.2; P = 0.007), antimicrobial therapy during the exposure time (5.36; 2.28-12.6; P < 0.001), use of at least one invasive procedure (2.99; 1.25-7.15; P = 0.014), number of invasive procedures (1.52; 1.05-2.19; P = 0.025), and geographical proximity (2.84; 1.15-7.00; P = 0.023) were associated with CPE acquisition. By multivariate analysis, antimicrobial therapy during the exposure time (odds ratio: 6.36; 95% confidence interval: 2.46-16.44; P < 0.001), at least one invasive procedure (2.92; 1.04-8.17; P = 0.041), and geographical proximity (3.69; 1.15-11.86; P = 0.028) were associated with acquisition. In this study, geographical proximity, invasive procedure, and antimicrobial therapy during exposure time were significantly associated with KP-OXA-48 acquisition. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  13. Evaluation of occupational allergic contact dermatitis and its related factors in Iran.

    PubMed

    Nassiri-Kashani, Mansour; Nassiri-Kashani, Mohammad Hassan; Ghafari, Mostafa

    2016-01-01

    Background: Occupational contact dermatitis, especially in hand, is one of the most common occupational disorders. The present study aimed at evaluating patients with occupational allergic contact dermatitis (ACD) caused by common allergens based on occupation type and disease history. Methods: This cross-sectional study aimed at evaluating the data of the patients with probable diagnosis of ACD in Center for Research and Training in Skin Diseases and Leprosy (CRTSDL) in Iran. In the present study, 946 patients were assessed from different regions of Iran. One hundred fifty-one cases with positive patch test and relevant exposure were entered into the study; data related to their occupation and disease activity history were evaluated and recorded. Then, factors related to disease activity history were assessed considering the occupational groups and common exposures. Results: Nickel sulphate was the most common allergen in the 151 patients. Disease activity was constant in 29.8% of the patients; it increased in 27.8%, and decreased just before doing the patch test in 42.4%. Of the patients, 52.3% were getting worse during the working days. Occupational groups were significantly different in age and gender. Disease duration was also different in the occupational groups (p=0.001). The least disease duration was observed in healthcare workers, and the most in service workers. Lesions in the foot were related to period of employment. In administrative work group, (teachers, technicians and housewives) disease activity was decreased in the most cases, while it was increased in most patients of service workers (p=0.086). Conclusion: The present study, similar to previous reports, revealed that nickel sulphate is the most common allergen in ACD cases. Moreover, it was found that the symptoms of disease activity remained constant or increased in a significant proportion of the cases during the working days. Therefore, these workers should seriously follow up on this matter

  14. Activation of clotting factor XI without detectable contact activation in experimental human endotoxemia.

    PubMed

    Minnema, M C; Pajkrt, D; Wuillemin, W A; Roem, D; Bleeker, W K; Levi, M; van Deventer, S J; Hack, C E; ten Cate, H

    1998-11-01

    Evidence of factor XI (FXI) activation in vivo is scarce. In addition, it remains uncertain whether thrombin, factor XIIa (FXIIa), or perhaps another protease is responsible for FXI conversion. We investigated the activation of FXI in eight healthy volunteers after infusion of a low dose of endotoxin (4 ng/kg of body weight). Activation of prekallikrein FXII, FXI, and prothrombin was measured with sensitive enzyme-linked immunosorbent assays (ELISAs), and FXI activation was measured with a novel enzyme capture assay that detects noncomplexed FXIa. Activation of FXI was apparent with a significant plasma peak level of noncomplexed FXIa of 10 to 11 pmol/L at 1 and 2 hours after endotoxin infusion, followed by a gradual increase in FXIa-FXIa inhibitor complexes, measured in the ELISAs, with a summit of 11 to 15 pmol/L at 6 and 24 hours, respectively. In accordance with previous studies, thrombin generation was detected 1 hour after endotoxin infusion to become maximal after 3 to 4 hours. In contrast, we did not find any evidence of contact activation, because markers of activation of prekallikrein and FXII remained undetectable. From the FXIa data a theoretical model was constructed which suggested that inhibition of FXIa does not take place in the plasma compartment, but is localized on a surface. These data provide the first evidence for FXI activation in low-grade endotoxemia and suggest that FXI is activated independently of FXII. Copyright 1998 by The American Society of Hematology

  15. Mental Health and Substance Use Factors Associated with Unwanted Sexual Contact among U.S. Active Duty Service Women

    PubMed Central

    Stahlman, Shauna; Javanbakht, Marjan; Cochran, Susan; Hamilton, Alison B.; Shoptaw, Steven; Gorbach, Pamina M.

    2015-01-01

    Many U.S. military women are exposed to unwanted sexual contact during military service, which can have important implications for mental health. Using data from the 2008 Department of Defense Survey of Health Related Behaviors, we employed multiple logistic regression methods to examine whether unwanted sexual contact was associated with stress, screening positive for mental disorders, or substance use, among active duty service women. The sample included 7,415 female military personnel, of whom 13.4% reported unwanted sexual contact (including any touching of genitals) since entering the military. After adjusting for potentially confounding variables, factors independently associated with unwanted sexual contact included military-related stress (Adjusted Odds Ratio [AOR] = 2.44), family/personal life-related stress (AOR = 1.78), and gender-related stress (AOR = 1.98) in the past 12 months. In addition, screening positive for depression, anxiety, posttraumatic stress disorder, psychological distress, and suicidal ideation or attempt were associated with unwanted sexual contact (AOR = 1.57–2.11). For drug/alcohol use, only misuse of tranquilizers/muscle relaxers (past 12 months) was associated with report of unwanted sexual contact (AOR = 1.35). Given the prevalence of unwanted sexual contact and corresponding adverse health outcomes in this sample of active duty women, strategies to create military structural/cultural changes and reduce gender-related stress and sexism are needed. PMID:25976935

  16. Evaluation of surface water characteristics of novel daily disposable contact lens materials, using refractive index shifts after wear

    PubMed Central

    Schafer, Jeffery; Steffen, Robert; Reindel, William; Chinn, Joseph

    2015-01-01

    Purpose Contact lens wearers today spend much time using digital display devices. Contact lens manufacturers are challenged to develop products that account for longer periods of time where blink rate is reduced and tear-film evaporation rate is increased, affecting both visual acuity and comfort. Two manufacturers recently introduced novel daily disposable contact lenses with high surface water content. The objective of the present study was to compare surface water characteristics before and after initial wear of recently introduced nesofilcon A and delefilcon A high surface water lenses with those of etafilcon A lenses. Patients and methods Twenty healthy subjects wore each of the three lens types studied in a randomly determined order for 15 minutes. After each wearing, lenses were removed and the surface refractive index (RI) of each lens was immediately measured. Results The mean RI of the unworn delefilcon A lens was 1.34, consistent with water content in excess of 80%. After 15 minutes of wear, the surface RI shifted to 1.43, consistent with its reported 33% bulk water content. In contrast, the mean surface RI of the nesofilcon A lens was 1.38, both initially and after 15 minutes of wear, and that of the etafilcon A lens was 1.41 initially and 1.42 after 15 minutes of wear. Conclusion The surface of the delefilcon A lens behaves like a high water hydrogel upon insertion but quickly dehydrates to behave like its low-water silicone-hydrogel bulk material with respect to surface water content during wear, while both nesofilcon A and etafilcon A lenses maintain their water content during initial wear. The nesofilcon A lens appears unique among high water lenses in maintaining high surface and bulk water content during wear. This is important because changes in surface RI due to dehydration are reported to lead to visual aberration affecting user experience. PMID:26543349

  17. Non-contact assessment of COD and turbidity concentrations in water using diffuse reflectance UV-Vis spectroscopy.

    PubMed

    Agustsson, Jon; Akermann, Oliver; Barry, D Andrew; Rossi, Luca

    2014-08-01

    Water contamination is an important environmental concern underlining the need for reliable real-time information on contaminant concentrations in natural waters. Here, a new non-contact UV-Vis spectroscopic approach for monitoring contaminants in water, and especially wastewater, is proposed. Diffuse reflectance UV-Vis spectroscopy was applied to measure simultaneously the chemical oxygen demand (COD) and turbidity (TUR) concentrations in water. The measurements were carried out in the wavelength range from 200-1100 nm. The measured spectra were analysed using partial-least-squares (PLS) regression. The correlation coefficient between the measured and the reference concentrations of COD and TUR in the water samples were R(2) = 0.85 and 0.96, respectively. These results highlight the potential of non-contact UV-Vis spectroscopy for the assessment of water contamination. A system built on the concept would be able to monitor wastewater pollution continuously, without the need for laborious sample collection and subsequent laboratory analysis. Furthermore, since no parts of the system are in contact with the wastewater stream the need for maintenance is minimised.

  18. Hand-to-mouth contacts result in greater ingestion of feces than dietary water consumption in Tanzania: a quantitative fecal exposure assessment model.

    PubMed

    Mattioli, Mia Catharine M; Davis, Jennifer; Boehm, Alexandria B

    2015-02-03

    Diarrheal diseases kill 1800 children under the age of five die each day, and nearly half of these deaths occur in sub-Saharan Africa. Contaminated drinking water and hands are two important environmental transmission routes of diarrhea-causing pathogens to young children in low-income countries. The objective of this research is to evaluate the relative contribution of these two major exposure pathways in a low-income country setting. A Monte Carlo simulation was used to model the amount of human feces ingested by children under five years old from exposure via hand-to-mouth contacts and stored drinking water ingestion in Bagamoyo, Tanzania. Child specific exposure data were obtained from the USEPA 2011 Exposure Factors Handbook, and fecal contamination was estimated using hand rinse and stored water fecal indicator bacteria concentrations from over 1200 Tanzanian households. The model outcome is a distribution of a child's daily dose of feces via each exposure route. The model results show that Tanzanian children ingest a significantly greater amount of feces each day from hand-to-mouth contacts than from drinking water, which may help elucidate why interventions focused on water without also addressing hygiene often see little to no effect on reported incidence of diarrhea.

  19. The role of water in the molecular structure and properties of soft contact lenses and surface interactions

    NASA Astrophysics Data System (ADS)

    Monti, Patrizia; Simoni, Rosa

    1992-06-01

    The role played by water in the molecular structure and properties of commercial soft contact lenses (hydrogels) based on poly 2-hydroxyethyl methacrylate (PHEMA) or poly vinylpyrrolidone (PVP) was investigated by means of vibrational spectroscopy and thermal analyses. The results of this study show that the materials having the greatest water percentage have elastic properties closer to those of the ocular tissues with which they come into contact. Water interacts by hydrogen bonding with the hydrophilic groups present in the polymers, and the strength of this interaction depends on the type of hydrophilic group involved. Moreover, in the case of PVP materials, water also modifies the conformation of the hydrophobic groups. The arrangement of surface water molecules can explain the different adhesion capability of Staphilococcus aureus on this type of lens depending on the water content. In connection with this, a simple model is presented. The water molecules present in the hydrogel structures completely exchange with those of the biological environment. A quantitative analytical method for evaluating the amount of water in commercial lenses by means of Raman spectroscopy is reported.

  20. Human water contacts patterns in Schistosoma mansoni epidemic foci in northern Senegal change according to age, sex and place of residence, but are not related to intensity of infection.

    PubMed

    Scott, J T; Diakhaté, M; Vereecken, K; Fall, A; Diop, M; Ly, A; De Clercq, D; de Vlas, S J; Berkvens, D; Kestens, L; Gryseels, B

    2003-02-01

    In an epidemic focus in northern Senegal, adults had lower intensities of infection than adolescents, a phenomenon that could not be attributed to immunity acquired over the previous 10-15 years of exposure to the parasite because all age groups had had the same number of years' experience of the worm. This article considers whether this pattern could have been because of higher levels of exposure to the parasite in younger age groups. Personal contact with infected water was recorded using a questionnaire in Schistosoma mansoni foci not more than 3 years old and in another, 10-year-old focus. Many aspects of contact (e.g. frequency, duration or time of day of contact) may contribute to the number of encounters with infective cercariae (true exposure), so various assumptions regarding the relationship between water contact and true exposure were tested resulting in a range of exposure indices. People reported a mean of 4.4 separate contacts, and spent a median of 57 min per day in water. Patterns of water contact differed depending on the exposure index used, e.g. considering duration, males spent a longer time in water than females (P < 0.001). But using frequency, females had more contacts with water than males in most villages (P < 0.001). Generally, exposure levels dropped as people become aged (P < 0.001) and residents of the older focus were more exposed than residents of other foci (P < 0.002). Intensity of (re)infection was not related to exposure either alone or in models incorporating age, sex and/or village irrespective of the index used. There is therefore evidence that age, sex and place of residence determine exposure but none to suggest that exposure had an influence on the relationship between these factors and intensity of infection. We propose therefore that in this population other factors have principal importance in determining intensity of infection.

  1. Spontaneous changes in contact angle of water and oil on novel flip-flop-type hydrophobic multilayer coatings

    NASA Astrophysics Data System (ADS)

    Kawamura, Go; Ema, Tomoyuki; Sakamoto, Hisatoshi; Wei, Xing; Muto, Hiroyuki; Matsuda, Atsunori

    2014-04-01

    Multilayer structures composed of poly(allylamine hydrochloride) (PAH) and Nafion were fabricated on glass substrates by layer-by-layer assembly. Some of the multilayers demonstrated spontaneous changes in contact angle of water and oil due to flip-flop movements of free sulfo groups in the Nafion layer, and the multilayers eventually possessed water repellency in air and oil repellency in water. The repellencies were enhanced by applying primer layers that were formed using SiO2 fine particles to increase surface roughness. Compared to typical hydrophobic and oleophobic surfaces, the multilayers showed practical levels for a use as soil release coatings.

  2. Wettability of supercritical carbon dioxide/water/quartz systems: simultaneous measurement of contact angle and interfacial tension at reservoir conditions.

    PubMed

    Saraji, Soheil; Goual, Lamia; Piri, Mohammad; Plancher, Henry

    2013-06-11

    Injection of carbon dioxide in deep saline aquifers is considered as a method of carbon sequestration. The efficiency of this process is dependent on the fluid-fluid and rock-fluid interactions inside the porous media. For instance, the final storage capacity and total amount of capillary-trapped CO2 inside an aquifer are affected by the interfacial tension between the fluids and the contact angle between the fluids and the rock mineral surface. A thorough study of these parameters and their variations with temperature and pressure will provide a better understanding of the carbon sequestration process and thus improve predictions of the sequestration efficiency. In this study, the controversial concept of wettability alteration of quartz surfaces in the presence of supercritical carbon dioxide (sc-CO2) was investigated. A novel apparatus for measuring interfacial tension and contact angle at high temperatures and pressures based on Axisymmetric Drop Shape Analysis with no-Apex (ADSA-NA) method was developed and validated with a simple system. Densities, interfacial tensions, and dynamic contact angles of CO2/water/quartz systems were determined for a wide range of pressures and temperatures relevant to geological sequestration of CO2 in the subcritical and supercritical states. Image analysis was performed with ADSA-NA method that allows the determination of both interfacial tensions and contact angles with high accuracy. The results show that supercritical CO2 alters the wettability of quartz surface toward less water-wet conditions compared to subcritical CO2. Also we observed an increase in the water advancing contact angles with increasing temperature indicating less water-wet quartz surfaces at higher temperatures.

  3. Enzymatic surface modification and functionalization of PET: a water contact angle, FTIR, and fluorescence spectroscopy study.

    PubMed

    Donelli, Ilaria; Taddei, Paola; Smet, Philippe F; Poelman, Dirk; Nierstrasz, Vincent A; Freddi, Giuliano

    2009-08-01

    The purpose of this study was to investigate the changes induced by a lypolytic enzyme on the surface properties of polyethylene terephthalate (PET). Changes in surface hydrophilicity were monitored by means of water contact angle (WCA) measurements. Fourier Transform Infrared spectroscopy (FTIR) in the Attenuated Total Reflectance mode (ATR) was used to investigate the structural and conformational changes of the ethylene glycol and benzene moieties of PET. Amorphous and crystalline PET membranes were used as substrate. The lipolytic enzyme displayed higher hydrolytic activity towards the amorphous PET substrate, as demonstrated by the decrease of the WCA values. Minor changes were observed on the crystalline PET membrane. The effect of enzyme adhesion was addressed by applying a protease after-treatment which was able to remove the residual enzyme protein adhering to the surface of PET, as demonstrated by the behavior of WCA values. Significant spectral changes were observed by FTIR-ATR analysis in the spectral regions characteristic of the crystalline and amorphous PET domains. The intensity of the crystalline marker bands increased while that of the amorphous ones decreased. Accordingly, the crystallinity indexes calculated as band intensity ratios (1,341/1,410 cm(-1) and 1,120/1,100 cm(-1)) increased. Finally, the free carboxyl groups formed at the surface of PET by enzyme hydrolysis were esterified with a fluorescent alkyl bromide, 2-(bromomethyl)naphthalene (BrNP). WCA measurements confirmed that the reaction proceeded effectively. The fluorescence results indicate that the enzymatically treated PET films are more reactive towards BrNP. FTIR analysis showed that the surface of BrNP-modified PET acquired a more crystalline character.

  4. Effect of Annealing Temperature on the Water Contact Angle of PVD Hard Coatings

    PubMed Central

    Yang, Yu-Sen; Cho, Ting-Pin

    2013-01-01

    Various PVD (physical vapor deposition) hard coatings including nitrides and metal-doped diamond-like carbons (Me-DLC) were applied in plastic injection and die-casting molds to improve wear resistance and reduce sticking. In this study, nitrides hcp-AlN (hexagonal close-packed AlN), Cr2N, (CrAl)2N) and Me-DLC (Si-DLC and Cr-DLC) coatings were prepared using a closed field unbalanced magnetron reactive sputtering system. The coatings were annealed in air for 2 h at various temperatures, after which the anti-sticking properties were assessed using water contact angle (WCA) measurements. The as-deposited hcp-AlN, Cr2N and (CrAl)2N coatings exhibit hydrophobic behavior and exhibit respective WCAs of 119°, 106° and 101°. The as-deposited Si-DLC and Cr-DLC coatings exhibit hydrophilic behavior and exhibit respective WCAs of 74° and 88°. The annealed Cr2N and (CrAl)2N coatings exhibit hydrophobic behavior with higher WCAs, while the annealed hcp-AlN, Si-DLC and Cr-DLC coatings are hydrophilic. The increased WCA of the annealed Cr2N and (CrAl)2N coatings is related to their crystal structure and increased roughness. The decreased WCA of the annealed hcp-AlN, Si-DLC and Cr-DLC coatings is related to their crystal structures and has little correlation with roughness. PMID:28811440

  5. Factors that trigger emergency physicians to contact a poison centre: findings from a Swiss study.

    PubMed

    Schurter, David; Rauber-Lüthy, Christine; Jahns, Maximilian; Haberkern, Monika; Kupferschmidt, Hugo; Exadaktylos, Aristomenis; Eriksson, Urs; Ceschi, Alessandro

    2014-03-01

    Poison centres offer rapid and comprehensive support for emergency physicians managing poisoned patients. This study investigates institutional, case-specific and poisoning-specific factors which influence the decision of emergency physicians to contact a poison centre. Retrospective, consecutive review of all poisoning-related admissions to the emergency departments (EDs) of a primary care hospital and a university hospital-based tertiary referral centre during 2007. Corresponding poison centre consultations were extracted from the poison centre database. Data were matched and analysed by logistic regression and generalised linear mixed models. 545 poisonings were treated in the participating EDs (350 (64.2%) in the tertiary care centre, 195 (35.8%) in the primary care hospital). The poison centre was consulted in 62 (11.4%) cases (38 (61.3%) by the tertiary care centre and 24 (38.7%) by the primary care hospital). Factors significantly associated with poison centre consultation included gender (female vs male) (OR 2.99; 95% CI 1.69 to 5.29; p<0.001), number of ingested substances (>1 vs 1) (OR 2.84; 95% CI 1.65 to 4.9; p<0.001) and situation (accidental vs intentional) (OR 2.76; 95% CI 1.05 to 7.25; p=0.039). In contrast, age, medical history and hospital size did not influence poison centre consultation. Poison centre consultation was significantly higher during the week, and significantly less during night shifts. The poison centre was consulted significantly more when patients were admitted to intensive care units (OR 5.81; 95% CI 3.25 to 10.37; p<0.001). Asymptomatic and severe versus mild cases were associated with more frequent consultation (OR 4.48; 95% CI 1.78 to 11.26; p=0.001 and OR 2.76; 95% CI 1.42 to 5.38; p=0.003). We found low rates of poison centre consultation by emergency physicians. It appears that intensive care unit admission and other factors reflecting either complexity or uncertainty of the clinical situation are the strongest predictors

  6. Novel method for determining hydrogel and silicone hydrogel contact lens transmission curves and their spatially specific ultraviolet radiation protection factors.

    PubMed

    Walsh, James E; Koehler, Laura V; Fleming, David P; Bergmanson, Jan P G

    2007-03-01

    Anterior ocular tissues exposed to high levels of toxic ultraviolet (UV) radiation may undergo physiologic changes leading to diseases that can alter the ocular surface, particularly in the stem cell-rich limbal region. UV radiation-blocking hydrogel contact lenses provide protection across the ocular surface, which varies according to the lens thickness. A novel fiber optic spectrophotometer front-end system has been developed to measure lens transmission curves at test points across lens surfaces to determine optical properties based on the Beer-Lambert law. Factors determining the transmission curves include the hydrogel lens used, its refractive index, whether a UV radiation-blocking dopant is incorporated, the water content, and the thickness of the lens. Test lenses of equal power were placed over a detecting fiber optic and illuminated by a deuterium source, and transmission spectra were recorded. The small optical sampling size allowed the spectral transmission profile to be determined across the lens surface, and comparisons were made with different lenses. Transmission curves across the lenses showed greater UV radiation-blocking capacity at the thicker peripheral region, with the 50% cutoff wavelength moving toward the visible spectrum by 10 nm from the center to the periphery. In addition, the ability to determine the spatially specific absorption coefficient and the related UV radiation protection factor was demonstrated. The system measures spatial variation in lens transmission and comparing different lens types while overcoming many of the handling limitations of cuvette-based spectrophotometer methods. The data show good agreement with published transmission curves and allow intralens and interlens comparisons.

  7. Identification of a target cell permissive factor required for contact-dependent growth inhibition (CDI)

    PubMed Central

    Diner, Elie J.; Beck, Christina M.; Webb, Julia S.; Low, David A.; Hayes, Christopher S.

    2012-01-01

    Bacterial contact-dependent growth inhibition (CDI) is mediated by the CdiB/CdiA family of two-partner secretion proteins. CdiA effector proteins are exported onto the surface of CDI+ inhibitor cells, where they interact with susceptible bacteria and deliver effectors/toxins derived from their C-terminal regions (CdiA-CT). CDI+ cells also produce an immunity protein that binds the CdiA-CT and blocks its activity to prevent autoinhibition. Here, we show that the CdiA-CT from uropathogenic Escherichia coli strain 536 (UPEC536) is a latent tRNase that requires activation by the biosynthetic enzyme CysK (O-acetylserine sulfhydrylase A). UPEC536 CdiA-CT exhibits no nuclease activity in vitro, but cleaves within transfer RNA (tRNA) anti-codon loops when purified CysK is added. CysK and CdiA-CT form a stable complex, and their binding interaction appears to mimic that of the CysK/CysE cysteine synthase complex. CdiA-CT activation is also required for growth inhibition. Synthesis of CdiA-CT in E. coli cysK+ cells arrests cell growth, whereas the growth of ΔcysK mutants is unaffected by the toxin. Moreover, E. coli ΔcysK cells are completely resistant to inhibitor cells expressing UPEC536 CdiA, indicating that CysK is required to activate the tRNase during CDI. Thus, CysK acts as a permissive factor for CDI, providing a potential mechanism to modulate growth inhibition in target cells. PMID:22333533

  8. Risk factors for corneal infiltrative events during continuous wear of silicone hydrogel contact lenses.

    PubMed

    Szczotka-Flynn, Loretta; Lass, Jonathan H; Sethi, Ajay; Debanne, Sara; Benetz, Beth Ann; Albright, Matthew; Gillespie, Beth; Kuo, Jana; Jacobs, Michael R; Rimm, Alfred

    2010-11-01

    This study determined which microbiologic, clinical, demographic, and behavioral factors are associated with corneal infiltrative events (CIEs) during continuous wear of silicone hydrogel (SH) contact lenses. Subjects (n = 205) were fitted with lotrafilcon A lenses for continuous wear and observed for 1 year. The main exposures of interest were corneal staining and bacterial lens contamination. Kaplan-Meier (KM) plots were used to estimate the cumulative unadjusted probability of remaining CIE free, and Cox proportional hazards regression was used to model the hazard of having a CIE, as a function of key predictor variables. The KM-unadjusted cumulative probability of remaining CIE free was 73.3%. Approximately 53% of subjects had repeated episodes of corneal staining (mild or greater), and 11.3% had repeated episodes of moderate or greater corneal staining. Corneal staining was not associated with the development of a CIE. The frequency of substantial bacterial bioburden on worn lenses at the time of a CIE was 64.7%, compared with only 12.2% during uncomplicated wear. The presence of substantial lens bacterial bioburden was associated with the development of a CIE (adjusted hazards ratio [HR], 8.66; 95% confidence interval [CI], 2.88-26.01). Smoking was also associated with a CIE (adjusted HR, 4.13; 95% CI, 1.27-13.45). Corneal staining is common during continuous wear of SH lenses, but it is not associated with the development of a CIE. Smoking and substantial lens bacterial bioburden pose prominent risks of a CIE. In this study, more than 70% of the total risk of CIE in those with substantial lens bioburden is attributable to this exposure. (ClinicalTrials.gov number, NCT00727402).

  9. Risk Factors for Corneal Infiltrative Events during Continuous Wear of Silicone Hydrogel Contact Lenses

    PubMed Central

    Lass, Jonathan H.; Sethi, Ajay; Debanne, Sara; Benetz, Beth Ann; Albright, Matthew; Gillespie, Beth; Kuo, Jana; Jacobs, Michael R.; Rimm, Alfred

    2010-01-01

    Purpose. This study determined which microbiologic, clinical, demographic, and behavioral factors are associated with corneal infiltrative events (CIEs) during continuous wear of silicone hydrogel (SH) contact lenses. Methods. Subjects (n = 205) were fitted with lotrafilcon A lenses for continuous wear and observed for 1 year. The main exposures of interest were corneal staining and bacterial lens contamination. Kaplan-Meier (KM) plots were used to estimate the cumulative unadjusted probability of remaining CIE free, and Cox proportional hazards regression was used to model the hazard of having a CIE, as a function of key predictor variables. Results. The KM-unadjusted cumulative probability of remaining CIE free was 73.3%. Approximately 53% of subjects had repeated episodes of corneal staining (mild or greater), and 11.3% had repeated episodes of moderate or greater corneal staining. Corneal staining was not associated with the development of a CIE. The frequency of substantial bacterial bioburden on worn lenses at the time of a CIE was 64.7%, compared with only 12.2% during uncomplicated wear. The presence of substantial lens bacterial bioburden was associated with the development of a CIE (adjusted hazards ratio [HR], 8.66; 95% confidence interval [CI], 2.88–26.01). Smoking was also associated with a CIE (adjusted HR, 4.13; 95% CI, 1.27–13.45). Conclusions. Corneal staining is common during continuous wear of SH lenses, but it is not associated with the development of a CIE. Smoking and substantial lens bacterial bioburden pose prominent risks of a CIE. In this study, more than 70% of the total risk of CIE in those with substantial lens bioburden is attributable to this exposure. (ClinicalTrials.gov number, NCT00727402). PMID:20538985

  10. Effects of hysteresis of static contact angle (HSCA) and boundary slip on the hydrodynamics of water striders

    NASA Astrophysics Data System (ADS)

    Zheng, J.; Wang, B. S.; Chen, W. Q.; Han, X. Y.; Li, C. F.; Zhang, J. Z.; Yu, K. P.

    2016-11-01

    It is known that contact lines keep relatively still on solids until static contact angles exceed an interval of hysteresis of static contact angle (HSCA), and contact angles keep changing as contact lines relatively slide on the solid. Here, the effects of HSCA and boundary slip were first distinguished on the micro-curvature force (MCF) on the seta. Hence, the total MCF is partitioned into static and dynamic MCFs correspondingly. The static MCF was found proportional to the HSCA and related with the asymmetry of the micro-meniscus near the seta. The dynamic MCF, exerting on the relatively sliding contact line, is aroused by the boundary slip. Based on the Blake-Haynes mechanism, the dynamic MCF was proved important for water walking insects with legs slower than the minimum wave speed 23 c}\\cdot s^{-1} . As insects brush the water by laterally swinging legs backwards, setae on the front side of the leg are pulled and the ones on the back side are pushed to cooperatively propel bodies forward. If they pierce the water surface by vertically swinging legs downwards, setae on the upside of the legs are pulled, and the ones on the downside are pushed to cooperatively obtain a jumping force. Based on the dependency between the slip length and shear rate, the dynamic MCF was found correlated with the leg speed U, as F˜ C1U+C2 U^{2+ɛ} , where C1 and C2 are determined by the dimple depth. Discrete points on this curve could give fitted relations as F˜ Ub (Suter et al., J. Exp. Biol. 200, 2523-2538, 1997). Finally, the axial torque on the inclined and partially submerged seta was found determined by the surface tension, contact angle, HSCA, seta width, and tilt angle. The torque direction coincides with the orientation of the spiral grooves of the seta, which encourages us to surmise it is a mechanical incentive for the formation of the spiral morphology of the setae of water striders.

  11. Effects of hysteresis of static contact angle (HSCA) and boundary slip on the hydrodynamics of water striders

    NASA Astrophysics Data System (ADS)

    Zheng, J.; Wang, B. S.; Chen, W. Q.; Han, X. Y.; Li, C. F.; Zhang, J. Z.; Yu, K. P.

    2017-02-01

    It is known that contact lines keep relatively still on solids until static contact angles exceed an interval of hysteresis of static contact angle (HSCA), and contact angles keep changing as contact lines relatively slide on the solid. Here, the effects of HSCA and boundary slip were first distinguished on the micro-curvature force (MCF) on the seta. Hence, the total MCF is partitioned into static and dynamic MCFs correspondingly. The static MCF was found proportional to the HSCA and related with the asymmetry of the micro-meniscus near the seta. The dynamic MCF, exerting on the relatively sliding contact line, is aroused by the boundary slip. Based on the Blake-Haynes mechanism, the dynamic MCF was proved important for water walking insects with legs slower than the minimum wave speed 23 cm\\cdot s^{-1}. As insects brush the water by laterally swinging legs backwards, setae on the front side of the leg are pulled and the ones on the back side are pushed to cooperatively propel bodies forward. If they pierce the water surface by vertically swinging legs downwards, setae on the upside of the legs are pulled, and the ones on the downside are pushed to cooperatively obtain a jumping force. Based on the dependency between the slip length and shear rate, the dynamic MCF was found correlated with the leg speed U, as F˜ C1U+C2 U^{2+ɛ}, where C1 and C2 are determined by the dimple depth. Discrete points on this curve could give fitted relations as F˜ Ub (Suter et al., J. Exp. Biol. 200, 2523-2538, 1997). Finally, the axial torque on the inclined and partially submerged seta was found determined by the surface tension, contact angle, HSCA, seta width, and tilt angle. The torque direction coincides with the orientation of the spiral grooves of the seta, which encourages us to surmise it is a mechanical incentive for the formation of the spiral morphology of the setae of water striders.

  12. Contact isolation is a risk factor for venous thromboembolism in trauma patients.

    PubMed

    Reed, Christopher R; Ferguson, Robert A; Peng, Yiming; Collier, Bryan R; Bradburn, Eric H; Toms, Alice R; Fogel, Sandy L; Baker, Christopher C; Hamill, Mark E

    2015-11-01

    Contact isolation (CI) is a series of precautions used to prevent the transmission of medically significant infectious pathogens in the health care setting. Our institution's implementation of CI includes limiting patient movement to the assigned room. Our objective was to define the association between CI and venous thromboembolism (VTE) at our Level I trauma center. Our institution's prospective trauma database was retrospectively queried for all patients admitted to the trauma service between January 1, 2011, and December 31, 2012. Data including demographics, Injury Severity Score (ISS), preexisting medical conditions, injury type, and VTE development were collected. CI status data were obtained from our institution's infection control database. χ2 was used to examine the unadjusted relationship between CI status and VTE. As the groups were not equivalent, logistic regression was then used to examine the relationship between CI and VTE while adjusting for relevant covariates including sex, age, ISS, and comorbidities. Of the 4,423 trauma patients admitted during the study period, 4,318 (97.6%) had complete records and were included in subsequent analyses. A total of 249 (5.8%) of the patients were on CI. VTE occurred in 44 patients (17.7%) on CI versus 141 patients (3.5%) who were not isolated (p < 0.0001; odds ratio, 6.0; 95% confidence interval, 4.1-8.6). With the use of lasso [least absolute shrinkage and selection operator] regression to adjust for patient risk factors, this relationship remained highly significant (p < 0.0001; odds ratio, 2.61; 95% confidence interval, 1.7-4.0). CI, ISS, hospital length of stay, and cardiac comorbidity were associated with VTE. After adjustment for other risk factors, CI remained most strongly associated with VTE. Although any medical intervention may come with unintended consequences, the risks and benefits of CI in this population need to be reevaluated. Further study is planned to identify opportunities to mitigate

  13. On the uniqueness of the receding contact angle: effects of substrate roughness and humidity on evaporation of water drops.

    PubMed

    Pittoni, Paola G; Lin, Chia-Hui; Yu, Teng-Shiang; Lin, Shi-Yow

    2014-08-12

    Could a unique receding contact angle be indicated for describing the wetting properties of a real gas-liquid-solid system? Could a receding contact angle be defined if the triple line of a sessile drop is not moving at all during the whole measurement process? To what extent is the receding contact angle influenced by the intrinsic properties of the system or the measurement procedures? In order to answer these questions, a systematic investigation was conducted in this study on the effects of substrate roughness and relative humidity on the behavior of pure water drops spreading and evaporating on polycarbonate (PC) surfaces characterized by different morphologies. Dynamic, advancing, and receding contact angles were found to be strongly affected by substrate roughness. Specifically, a receding contact angle could not be measured at all for drops evaporating on the more rugged PC surfaces, since the drops were observed strongly pinning to the substrate almost until their complete disappearance. Substrate roughness and system relative humidity were also found responsible for drastic changes in the depinning time (from ∼10 to ∼60 min). Thus, for measurement observations not sufficiently long, no movement of the triple line could be noted, with, again, the failure to find a receding contact angle. Therefore, to keep using concepts such as the receding contact angle as meaningful specifications of a given gas-liquid-solid system, the imperative to carefully investigate and report the inner characteristics of the system (substrate roughness, topography, impurities, defects, chemical properties, etc.) is pointed out in this study. The necessity of establishing methodological standards (drop size, measurement method, system history, observation interval, relative humidity, etc.) is also suggested.

  14. A Long Term Study of the Water Content Changes in Three Types of Hydrogel Contact Lenses.

    DTIC Science & Technology

    1987-05-01

    in visual acuity , keratometric readings, and post-lens removal refractions? Appropriate statistical analysis of the data would be used to determine the...study. Visual acuities had to be correctable to 20/20 or better in each eye by both spectacles and contact lens. Participation in this study required...eye. This was done before and after lens removal. 4. Distant Snellen visual acuity --measured through contact lenses with a • -: Meanco projector and an

  15. Participation in contact or collision sports in athletes with epilepsy, genetic risk factors, structural brain lesions, or history of craniotomy.

    PubMed

    Miele, Vincent J; Bailes, Julian E; Martin, Neil A

    2006-10-15

    Despite a plethora of guidelines for return to play following mild head injury, a discussion of when and if an athlete should be allowed to participate in contact or collision sports if he or she sustains a structural brain lesion or after a head injury requiring craniotomy is lacking. The structural lesions discussed include arachnoid cyst, Chiari malformation Type I, cavum septum pellucidum, and the presence of ventriculoperitoneal shunts. Issues unique to this population with respect to the possibility of increased risk of head injury are addressed. The population of athletes with epilepsy and certain genetic risk factors is also discussed. Finally, the ability of athletes to participate in contact or collision sports after undergoing craniotomies for traumatic or congenital abnormalities is evaluated. Several known instances of athletes returning to contact sports following craniotomy are also reviewed.

  16. Photometric analysis of Kepler contact binaries with large fill-out factors: KIC 3221207 and KIC 6677225

    NASA Astrophysics Data System (ADS)

    Aliçavuş, Fahri; Soydugan, Faruk

    2017-02-01

    Contact binary stars have an important role to understand how the binary stars evolve to a single star and explain to the physical processes of star merges. Hence, understanding of different type of contact binaries is valuable to explore some physical processes such as angular momentum loses, mass and heat transfers between components. In this study, we present the photometric analysis of two Kepler binary stars KIC 3221207 and KIC 6677225. As a result, it was found that both eclipsing binaries have large amount of common envelopes. The fill-out factors of stars were determined to be 79 and 89 percent for KIC 3221207 and KIC 6677225, respectively. Furthermore, both systems show parabolic orbital period variations, while the third light contribution was found for KIC 3221207. In the result, we compare the target systems with similar, well-known contact binaries.

  17. Parametric Limits of Efficient Use of a Centrifugal Water Atomizer in Contact Waste-Gas Heat-Utilization Units

    NASA Astrophysics Data System (ADS)

    Bezrodnyi, M. K.; Rachinskii, A. Yu.; Barabash, P. A.; Goliyad, N. N.

    2016-07-01

    The relation for the limiting temperature of water heating in a contact gas-droplet-type apparatus with a centrifugal atomizer has been determined experimentally in relation to the conditions of utilization of heat of power plant waste-gases. Investigations were carried out in the range of excess water pressures in front of the atomizer 0.2-0.6 MPa and of the volume fraction of steam in the vapor-gas mixture at the inlet of the apparatus from 0.02 to 0.45. The possibility of using the obtained dependence for calculating the limiting values of the vapor-gas flow parameters that limit the range of efficient operation of the contact apparatus with steam condensation and in the absence of heated liquid droplet evaporation is shown.

  18. Assessment of microbial growth on the surface of materials in contact with water intended for human consumption using ATP method.

    PubMed

    Szczotko, Maciej; Krogulski, Adam

    2010-01-01

    Elaboration of an assessment method for plumbing materials contacting drinking water was the main purpose of this study. The investigation was conducted in 8 week cycles in dynamic conditions using a continuous flow reactor. Microbial growth was measured indirectly by a bioluminescence technique (ATP assay). Every week swabs from the surface of tested materials (polypropylene and different types of polyethylene), from the domestic market were collected and the level of bioluminescence was examined. The results obtained from the surface of tested materials were repeatable and clearly approximated those obtained from the surface of a negative control (stainless steel, low susceptibility for microbial growth). The level of bioluminescence (ATP) on the surface of positive control (paraffin, high susceptibility for microbial growth) was many times higher than that observed on other materials. The presented investigation was the main part of a validation process, which in short time will serve to initiate a complete assessment system for organic materials contacting drinking water.

  19. In vivo tissue engineering: mimicry of homing factors for self-endothelialization of blood-contacting materials.

    PubMed

    Avci-Adali, Meltem; Stoll, Heidi; Wilhelm, Nadja; Perle, Nadja; Schlensak, Christian; Wendel, Hans P

    2013-01-01

    Thrombogenicity of foreign surfaces is the major obstacle in cardiovascular interventions. Despite enormous advances in biomaterials research, the hemocompatibility of blood-contacting materials is still not satisfactory and the native endothelium still represents the ideal surface for blood contact. Circulating adult endothelial progenitor cells (EPCs) in the human blood provide an excellent source of autologous stem cells for the in vivo self-endothelialization of blood-contacting materials. For this purpose, material surfaces can be coated with capture molecules mimicking natural homing factors to attract circulating EPCs. Hitherto, several ligands, such as aptamers, monoclonal antibodies, peptides, selectins and their ligands, or magnetic molecules, are used to biofunctionalize surfaces for the capturing of EPCs directly from patient's bloodstream onto blood-contacting materials. Subsequently, attracted EPCs can differentiate into endothelial cells and generate an autologous endothelium. The in vivo self-endothelialization of blood-contacting materials prevents the recognition of them as a foreign body; this opens up revolutionary new prospects for future clinical stem-cell and tissue engineering strategies. Copyright © 2013 S. Karger AG, Basel.

  20. Physicochemical factors influencing bacterial transfer from contact lenses to surfaces with different roughness and wettability.

    PubMed

    Vermeltfoort, Pit B J; van der Mei, Henny C; Busscher, Henk J; Hooymans, Johanna M M; Bruinsma, Gerda M

    2004-11-15

    The aim of this study was to determine the transfer of Pseudomonas aeruginosa No. 3 and Staphylococcus aureus 835 from contact lenses to surfaces with different hydrophobicity and roughness. Bacteria were allowed to adhere to contact lenses (Surevue, PureVision, or Focus Night & Day) by incubating the lenses in a bacterial suspension for 30 min. The contaminated lenses were put on a glass, poly(methylmethacrylate), or silicone rubber substratum, shaped to mimic the eye. After 2 and 16 h, lenses were separated from the substrata and bacteria were swabbed off from the respective surfaces and resuspended in saline. Appropriate serial dilutions of these suspensions were made, from which aliquots were plated on agar for enumeration. Bacterial transfer varied between 4 and 60%, depending on the combination of strain, contact time, contact lens, and substratum surface. For P. aeruginosa No. 3, transfer was significantly higher after 16 h than after 2 h, whereas less increase with time was seen for S. aureus 835. Bacterial transfer from all tested contact lenses was least to silicone rubber, the most hydrophobic and roughest substratum surface included.

  1. Factors associated with textile pattern dermatitis caused by contact allergy to dyes, finishes, foams, and preservatives.

    PubMed

    Brookstein, David S

    2009-07-01

    From as early as 1869, textile dyes and subsequently finishes have been reported to cause various manifestations of contact dermatitis, from mild to severe and debilitating. The European Union, through Directive (2002/61/EC) to restrict the marketing and use of certain dangerous substances and preparations (azo colorants) in textile and leather products, has taken the worldwide lead in restricting some dyes as a result of their carcinogenic nature. Given the recent discovery of the new route to contact dermatitis, it is important to continue to be vigilant for new and unexpected sources of allergens from textile, apparel, and furniture items.

  2. Theory of the effect of the change in the pH of water upon contact with the surface of finely dispersed solids (flint)

    SciTech Connect

    Olodovskii, P.P.

    1995-10-01

    Based on estimates of the parameters of the structure of water in a water-flint powder system and the structure of water adsorbed on the surface of the flint, an explanation is given for the effect of the increase in the pH of water in contact with the flint.

  3. The association of drinking water treatment and distribution network disturbances with Health Call Centre contacts for gastrointestinal illness symptoms.

    PubMed

    Malm, Annika; Axelsson, Gösta; Barregard, Lars; Ljungqvist, Jakob; Forsberg, Bertil; Bergstedt, Olof; Pettersson, Thomas J R

    2013-09-01

    There are relatively few studies on the association between disturbances in drinking water services and symptoms of gastrointestinal (GI) illness. Health Call Centres data concerning GI illness may be a useful source of information. This study investigates if there is an increased frequency of contacts with the Health Call Centre (HCC) concerning gastrointestinal symptoms at times when there is a risk of impaired water quality due to disturbances at water works or the distribution network. The study was conducted in Gothenburg, a Swedish city with 0.5 million inhabitants with a surface water source of drinking water and two water works. All HCC contacts due to GI symptoms (diarrhoea, vomiting or abdominal pain) were recorded for a three-year period, including also sex, age, and geocoded location of residence. The number of contacts with the HCC in the affected geographical areas were recorded during eight periods of disturbances in the water works (e.g. short stops of chlorine dosing), six periods of large disturbances in the distribution network (e.g. pumping station failure or pipe breaks with major consequences), and 818 pipe break and leak repairs over a three-year period. For each period of disturbance the observed number of calls was compared with the number of calls during a control period without disturbances in the same geographical area. In total about 55, 000 calls to the HCC due to GI symptoms were recorded over the three-year period, 35 per 1000 inhabitants and year, but much higher (>200) for children <3 yrs of age. There was no statistically significant increase in calls due to GI illness during or after disturbances at the water works or in the distribution network. Our results indicate that GI symptoms due to disturbances in water works or the distribution network are rare. The number of serious failures was, however limited, and further studies are needed to be able to assess the risk of GI illness in such cases. The technique of using geocoded

  4. Predictive factors of delay in contact with a psychiatrist in depressive disorders: a sample of Iranian patients.

    PubMed

    Hosseini, Seyedeh Sahar; Rejali, Mehri; Kheirabadi, Gholam Reza; Aliyari, Roqayeh

    2014-03-01

    The different duration of delay to first contact with a psychiatrist in depressive disordered patients has been observed in western and non western cultures. This study aimed to examine the duration and predictive factors of delay in contact with a psychiatrist in depressive patients in Isfahan city of Iran. In This cross sectional study 156 depressive patients were recruited from various outpatient clinics in Isfahan city between January 2013 and February 2013. We used the Anderson Socio-Behavioral Model (ASBM) for examine the role of various factors influencing delay in help seeking. In this models there were three categories variables (predisposing, enabling and need factors). Quintile regression model was used to study the predictors. The median duration between symptom onset and first contact with a psychiatrist was 1 year. In the first step (predisposing model), age at onset of depressive symptoms and never married were negative predictors for delay, but widowed or divorced statues was positive predictors for delay. In the enabling model past contact with health provider was positively associated with duration of delay. In the need model, neither variable had a significant effect on duration of delay. In the full model, younger age at onset, widowed or divorced statues and past contact with health provider increased duration of delay. More delay of help seeking by children and adolescence and probability of maladaptive coping style such as substance use and complicating of situation need to earlier diagnosis of depression in young group and earlier treatment for decrease DALLY for MDD, Therefore we suggest the mental health awareness programs for adolescent in school, and more ever for the influenced roles of parent and other family members and teachers on teen and young person's life, the education for families and teachers on adolescent mental health problems can be effective. First help seeking contact with non-psychiatric medical professionals enhance the

  5. Sensory aspects and water quality impacts of chlorinated and chloraminated drinking water in contact with HDPE and cPVC pipe.

    PubMed

    Heim, Timothy H; Dietrich, Andrea M

    2007-02-01

    Pipes constructed with high-density polyethylene (HDPE) or chlorinated polyvinyl chloride (cPVC) are commonly used in drinking water distribution systems and premise plumbing. In this comprehensive investigation, the effects on odor, organic chemical release, trihalomethane (THM) formation, free chlorine demand and monochloramine demand were determined for water exposed to HDPE and cPVC pipes. The study was conducted in accordance with the Utility Quick Test (UQT), a migration/leaching protocol for analysis of materials in contact with drinking water. The sensory panel consistently attributed a weak to moderate intensity of a "waxy/plastic/citrus" odor to the water from the HDPE pipes but not the cPVC-contacted water samples. The odor intensity generated by the HDPE pipe remained relatively constant for multiple water flushes, and the odor descriptors were affected by disinfectant type. Water samples stored in both types of pipe showed a significant increase in the leaching of organic compounds when compared to glass controls, with HDPE producing 0.14 microgTOC/cm(2) pipe surface, which was significantly greater than the TOC release from cPVC. Water stored in both types of pipe showed disinfectant demands of 0.1-0.9 microg disinfectant/cm(2) pipe surface, with HDPE exerting more demand than cPVC. No THMs were detected in chlorinated water exposed to the pipes. The results demonstrate the impact that synthetic plumbing materials can have on sensory and chemical water quality, as well as the significant variations in drinking water quality generated from different materials.

  6. Piercing the water surface with a blade: Singularities of the contact line

    SciTech Connect

    Alimov, Mars M.; Kornev, Konstantin G.

    2016-01-15

    An external meniscus on a narrow blade with a slit-like cross section is studied using the hodograph formulation of the Laplace nonlinear equation of capillarity. On narrow blades, the menisci are mostly shaped by the wetting and capillary forces; gravity plays a secondary role. To describe a meniscus in this asymptotic case, the model of Alimov and Kornev [“Meniscus on a shaped fibre: Singularities and hodograph formulation,” Proc. R. Soc. A 470, 20140113 (2014)] has been employed. It is shown that at the sharp edges of the blade, the contact line makes a jump. In the wetting case, the contact line sitting at each side of the blade is lifted above the points where the meniscus first meets the blade edges. In the non-wetting case, the contact line is lowered below these points. The contours of the constant height emanating from the blade edges generate unusual singularities with infinite curvatures at some points at the blade edges. The meniscus forms a unique surface made of two mirror-symmetric sheets fused together. Each sheet is supported by the contact line sitting at each side of the blade.

  7. Piercing the water surface with a blade: Singularities of the contact line

    NASA Astrophysics Data System (ADS)

    Alimov, Mars M.; Kornev, Konstantin G.

    2016-01-01

    An external meniscus on a narrow blade with a slit-like cross section is studied using the hodograph formulation of the Laplace nonlinear equation of capillarity. On narrow blades, the menisci are mostly shaped by the wetting and capillary forces; gravity plays a secondary role. To describe a meniscus in this asymptotic case, the model of Alimov and Kornev ["Meniscus on a shaped fibre: Singularities and hodograph formulation," Proc. R. Soc. A 470, 20140113 (2014)] has been employed. It is shown that at the sharp edges of the blade, the contact line makes a jump. In the wetting case, the contact line sitting at each side of the blade is lifted above the points where the meniscus first meets the blade edges. In the non-wetting case, the contact line is lowered below these points. The contours of the constant height emanating from the blade edges generate unusual singularities with infinite curvatures at some points at the blade edges. The meniscus forms a unique surface made of two mirror-symmetric sheets fused together. Each sheet is supported by the contact line sitting at each side of the blade.

  8. Competitive adsorption of surfactants and hydrophilic silica particles at the oil-water interface: interfacial tension and contact angle studies.

    PubMed

    Pichot, R; Spyropoulos, F; Norton, I T

    2012-07-01

    The effect of surfactants' type and concentration on the interfacial tension and contact angle in the presence of hydrophilic silica particles was investigated. Silica particles have been shown to have an antagonistic effect on interfacial tension and contact angle in the presence of both W/O and O/W surfactants. Silica particles, combined with W/O surfactant, have no effect on interfacial tension, which is only dictated by the surfactant concentration, while they strongly affect interfacial tension when combined with O/W surfactants. At low O/W surfactant, both particles and surfactant are adsorbed at the interface, modifying the interface structure. At higher concentration, interfacial tension is only dictated by the surfactant. By increasing the surfactant concentration, the contact angle that a drop of aqueous phase assumes on a glass substrate placed in oil media decreases or increases depending on whether the surfactant is of W/O or O/W type, respectively. This is due to the modification of the wettability of the glass by the oil or water induced by the surfactants. Regardless of the surfactant's type, the contact angle profile was dictated by both particles and surfactant at low surfactant concentration, whereas it is dictated by the surfactant only at high concentration.

  9. Association of Urogenital Symptoms with History of Water Contact in Young Women in Areas Endemic for S. haematobium. A Cross-Sectional Study in Rural South Africa

    PubMed Central

    Galappaththi-Arachchige, Hashini Nilushika; Amlie Hegertun, Ingrid Elise; Holmen, Sigve; Qvigstad, Erik; Kleppa, Elisabeth; Sebitloane, Motshedisi; Ndhlovu, Patricia Doris; Vennervald, Birgitte Jyding; Gundersen, Svein Gunnar; Taylor, Myra; Kjetland, Eyrun Floerecke

    2016-01-01

    Female genital schistosomiasis is a neglected tropical disease caused by Schistosoma haematobium. Infected females may suffer from symptoms mimicking sexually transmitted infections. We explored if self-reported history of unsafe water contact could be used as a simple predictor of genital schistosomiasis. In a cross-sectional study in rural South Africa, 883 sexually active women aged 16–22 years were included. Questions were asked about urogenital symptoms and water contact history. Urine samples were tested for S. haematobium ova. A score based on self-reported water contact was calculated and the association with symptoms was explored while adjusting for other genital infections using multivariable logistic regression analyses. S. haematobium ova were detected in the urine of 30.5% of subjects. Having ova in the urine was associated with the water contact score (p < 0.001). Symptoms that were associated with water contact included burning sensation in the genitals (p = 0.005), spot bleeding (p = 0.012), abnormal discharge smell (p = 0.018), bloody discharge (p = 0.020), genital ulcer (p = 0.038), red urine (p < 0.001), stress incontinence (p = 0.001) and lower abdominal pain (p = 0.028). In S. haematobium endemic areas, self-reported water contact was strongly associated with urogenital symptoms. In low-resource settings, a simple history including risk of water contact behaviour can serve as an indicator of urogenital schistosomiasis. PMID:27854250

  10. Quantifying crop water stress factors from soil water measurements in a limited irrigation experiment

    USDA-ARS?s Scientific Manuscript database

    Quantifying crop water stress factors from soil water measurements in a limited irrigation experiment. A correct simulation of crop responses to water stress is essential for a system model. In this study, we investigated three methods of quantifying water deficit stresses based on soil water meas...

  11. Factors influencing early health facility contact and low default rate among new sputum smear positive tuberculosis patients, India.

    PubMed

    Bhardwaj, Ashok Kumar; Kashyap, Surender; Bansal, Pradeep; Kumar, Dinesh; Raina, Sunil Kumar; Chander, Vishav; Sharma, Sushant

    2014-01-01

    Early case identification and prompt treatment of new sputum smear positive case are important to reduce the spread of tuberculosis (TB). Present study was planned to study the associated factors for duration to contact the health facility since appearance of symptoms and treatment default. Methodology. It was prospective cohort study of TB patients already registered for treatment in randomly selected TB units (TUs) in Himachal Pradesh, India. Relative risk (RR) was calculated as risk estimate to find out the explanatory variables for early contact and default. Results. Total 1607 patients were recruited and 25 (1.5%) defaulted treatment. Patients from nuclear family (aRR: 1.37; 1.09-1.73), ashamed of TB (aRR: 1.32; 1.03-1.70), wishing to disclose disease status (aRR: 1.79; 1.43-2.24), but aware of curable nature (aRR: 1.67; 1.17-2.39) and preventable (aRR: 1.35; 1.07-1.70) nature of disease, contacted health facility early since appearance of symptoms. Conclusion. Better awareness and less misconceptions about disease influences the early contact of health facility and low default rate in North India.

  12. Membrane contacts between endosomes and ER provide sites for PTP1B-epidermal growth factor receptor interaction.

    PubMed

    Eden, Emily R; White, Ian J; Tsapara, Anna; Futter, Clare E

    2010-03-01

    The epidermal growth factor receptor (EGFR) is a critical determinator of cell fate. Signalling from this receptor tyrosine kinase is spatially regulated by progression through the endocytic pathway, governing receptor half-life and accessibility to signalling proteins and phosphatases. Endocytosis of EGFR is required for interaction with the protein tyrosine phosphatase PTP1B (ref. 1), which localizes to the cytoplasmic face of the endoplasmic reticulum (ER), raising the question of how PTP1B comes into contact with endosomal EGFR. We show that EGFR-PTP1B interaction occurs by means of direct membrane contacts between the perimeter membrane of multivesicular bodies (MVBs) and the ER. The population of EGFR interacting with PTP1B is the same population that undergo ESCRT-mediated (endosomal sorting complex required for transport) sorting within MVBs, and PTP1B activity promotes the sequestration of EGFR on to MVB internal vesicles. Membrane contacts between endosomes and the ER form in both the presence and absence of stimulation by EGF. Thus membrane contacts between endosomes and the ER may represent a global mechanism for direct interaction between proteins on these two organelles.

  13. The design of contact lens based ocular drug delivery systems for single-day use: Part (I) Structural factors, surrogate ophthalmic dyes and passive diffusion studies.

    PubMed

    Mahomed, Anisa; Tighe, Brian J

    2014-09-01

    The poor retention and efficacy of instilled drops as a means of delivering drugs to the ophthalmic environment is well-recognised. The potential value of contact lenses as a means of ophthalmic drug delivery, and consequent improvement of pre-corneal retention is one obvious route to the development of a more effective ocular delivery system. Furthermore, the increasing availability and clinical use of daily disposable contact lenses provides the platform for the development of viable single-day use drug delivery devices based on existing materials and lenses. In order to provide a basis for the effective design of such devices, a systematic understanding of the factors affecting the interaction of individual drugs with the lens matrix is required. Because a large number of potential structural variables are involved, it is necessary to achieve some rationalisation of the parameters and physicochemical properties (such as molecular weight, charge, partition coefficients) that influence drug interactions. Ophthalmic dyes and structurally related compounds based on the same core structure were used to investigate these various factors and the way in which they can be used in concert to design effective release systems for structurally different drugs. Initial studies of passive diffusional release form a necessary precursor to the investigation of the features of the ocular environment that over-ride this simple behaviour. Commercially available contact lenses of differing structural classifications were used to study factors affecting the uptake of the surrogate actives and their release under 'passive' conditions. The interaction between active and lens material shows considerable and complex structure dependence, which is not simply related to equilibrium water content. The structure of the polymer matrix itself was found to have the dominant controlling influence on active uptake; hydrophobic interaction with the ophthalmic dye playing a major role. © The

  14. Skill qualities as risk factors for contact injury in professional rugby league players.

    PubMed

    Gabbett, Tim J; Ullah, Shahid; Jenkins, David; Abernethy, Bruce

    2012-01-01

    We investigated the relationship between skill qualities and contact injury risk in professional rugby league players. Sixty-six professional rugby league players aged 23 ± 4 years (mean ± s) participated in this three-year prospective study. Players underwent assessments of tackling proficiency, dual-task draw-and-pass proficiency, reactive agility, pattern recall, and pattern prediction. The frailty model was applied to calculate the adjusted risk ratios of injury. When the players' age and playing position were adjusted in the frailty model, the risk ratios showed that reactive agility was a predictor for the risk of injury. Players with reactive agility decision times of >80 ms had a lower incidence (relative risk = 0.68, 95% CI 0.47-0.98, P = 0.04) of injuries than players with reactive agility decision times of ≤ 80 ms. Although there was no relationship between injury and the majority of skill qualities (P = 0.47-0.93), players with poor reactive agility performances (specifically longer decision times) had a lower risk of injury, suggesting that poor perceptual skill is protective against contact injuries in professional rugby league players. These players might inadvertently avoid the heavy collisions that result in injury, or at best result in partial contact that does not result in exposure to the full force of a tackle.

  15. [Isothiazolinones as causal factors of contact allergy epidemics in the 20th and 21st centuries].

    PubMed

    Chomiczewska-Skóra, Dorota; Kręcisz, Beata; Kieć-Świerczyńska, Marta

    2014-01-01

    Chloromethylisothiazolinone (MCI) and methylisothiazolinone (MI) have been widely used as preservatives in cosmetics, household products and industrial products since the late 1970s. First cases of contact allergy to the MCI/MI combination were noted in 1980-1982 in Sweden. Then, a significant increase in the frequency of sensitization to these compounds was observed in many European centers. The increase has been stopped by the introduction of legislation on their maximum concentrations in consumer and industrial products in Europe and in some non-European countries. But approval of the use of MI alone without limits in industrial products (from 2000) and at a maximum concentration of 100 ppm in cosmetics (from 2005) resulted in an unprecedented increase in the number of individuals sensitized to this compound. Allergic contact dermatitis due to MI occurs in both adults and children. It is often manifested by severe symptoms, which may be also induced by airborne exposure. The most important sources of sensitization include cosmetic products and paints. To counteract the increasing problem of contact allergy epidemic to MI, the recommendations have been developed, suggesting the ban on the use of MI in "leave-on" cosmetics and maximum concentration of 15 ppm in "rinse-off" products. The recommendations are likely to be implemented in 2014.

  16. Molecular Dynamics Study of the Effect of Interaction Parameters on the Contact Angle and Interface Thermal Transport between Water and Aluminum (Preprint)

    DTIC Science & Technology

    2015-10-15

    AFRL-RX-WP-JA-2016-0324 MOLECULAR DYNAMICS STUDY OF THE EFFECT OF INTERACTION PARAMETERS ON THE CONTACT ANGLE AND INTERFACE THERMAL...INTERACTION PARAMETERS ON THE CONTACT ANGLE AND INTERFACE THERMAL TRANSPORT BETWEEN WATER AND ALUMINUM (PREPRINT) 5a. CONTRACT NUMBER FA8650-11-D-5401...Molecular dynamics simulations are utilized to predict the effect of Al-O interaction parameter on the contact angle and thermal interface

  17. The effect of physical and chemical properties of swimming pool water and its close environment on the development of contact dermatitis in hydrotherapists.

    PubMed

    Pardo, A; Nevo, K; Vigiser, D; Lazarov, A

    2007-02-01

    The association between physical and chemical parameters in swimming pool water and the incidence of contact dermatitis (CD) in hydrotherapists was studied. Chemical and physical parameters characterizing the water and air environment of swimming pools conducting hydrotherapy program were recorded. Differences between the values of these parameters associated with affected and non-affected hydrotherapists employed in 39 pools were tested statistically. No significant difference was found between the means of each of the physical and chemical parameters associated with the affected and the non-affected group of hydrotherapists. The prevalence ratio of the incidence of CD in pools chlorinated by gaseous chlorine was significantly higher than that in pools disinfected by other forms of chlorine compounds (PR = 1.49, CI = 1.17-1.89, P = 0.017). Dosing the water with larger amounts of gaseous chlorine compared to other disinfectants and a subsequent temporary decrease in the pH of the water may produce a more aggressive environment. It is suggested that combined effect of the various factors concomitantly with the irritating effect of prolonged exposure to water may trigger CD in pools treated with other chlorine-based compounds.

  18. A Comparative Study Between an Oil-in-Water Emulsion and Nonlipid Eye Drops Used for Rewetting Contact Lenses.

    PubMed

    Guthrie, Sarah E; Jones, Lyndon; Blackie, Caroline A; Korb, Donald R

    2015-11-01

    The purpose of this study was to determine the clinical impact of using SYSTANE BALANCE Lubricant Eye Drops (Alcon, Fort Worth, TX), an oil-in-water emulsion, as a rewetting eye drop in symptomatic contact lens wearers. Subjects who had previously experienced contact lens discomfort (CLD), with a mean lens wearing history of 18.6±12.8 years, were randomly assigned to use a Test (SYSTANE BALANCE Lubricant Eye Drops; n=76) or control (habitual nonlipid contact lens rewetting eye drop; n=30) drop over their contact lenses within 5 min of lens insertion and then subsequently at 2 hr intervals up to a maximum of 4 drops per eye daily for a 1-month period. Assessments of subjective comfort, comfortable wearing time, lid wiper epitheliopathy (LWE), and corneal staining were conducted at baseline and after 1 month, after 6 hr of lens wear. Comfort, wearing time, LWE, and corneal staining all showed statistically significant improvements in the test group using SYSTANE BALANCE Lubricant Eye Drops at the 1-month visit compared with baseline data (all P<0.01) and compared with the control group at the 1-month visit (P<0.01, P=0.01, P<0.01, and P=0.03, respectively). The use of SYSTANE BALANCE Lubricant Eye Drops as a rewetting drop in a group of wearers who experienced symptoms of CLD improved subjective comfort scores, increased comfortable wearing time, and reduced signs of LWE and corneal staining, when compared with the use of non-lipid-containing contact lens rewetting eye drops.

  19. Back-contacted and small form factor GaAs solar cell.

    SciTech Connect

    Clews, Peggy Jane; Wanlass, Mark W.; Sanchez, Carlos A.; Pluym, Tammy; Cruz-Campa, Jose Luis; Okandan, Murat; Gupta, Vipin P.; Nielson, Gregory N.; Resnick, Paul James

    2010-07-01

    We present a newly developed microsystem enabled, back-contacted, shade-free GaAs solar cell. Using microsystem tools, we created sturdy 3 {micro}m thick devices with lateral dimensions of 250 {micro}m, 500 {micro}m, 1 mm, and 2 mm. The fabrication procedure and the results of characterization tests are discussed. The highest efficiency cell had a lateral size of 500 {micro}m and a conversion efficiency of 10%, open circuit voltage of 0.9 V and a current density of 14.9 mA/cm{sup 2} under one-sun illumination.

  20. Patch testing for allergic contact dermatitis to cigarettes: smoked/unsmoked components and formaldehyde factors.

    PubMed

    Carew, Benjamin; Muir, Jim

    2014-08-01

    A patient with hand dermatitis reported that switching her smoking hand resulted in reduced symptoms. When allergy to cigarettes is suspected the literature supports standard allergy testing as well as testing the individual components of cigarettes. Initial standard patch testing revealed an allergy to formaldehyde and the formaldehyde releasing agent, quaternium-15. The patient did not react to her usual roll-your-own cigarette components but reacted to the smoked filter paper of a particular brand of cigarette she frequently borrowed from a friend. Possible explanations include either a variation of ingredients between cigarettes that alters the formaldehyde concentration or another unidentified allergen in the branded cigarette causing allergic contact dermatitis.

  1. Elucidation of eukaryotic elongation factor-2 contact sites within the catalytic domain of Pseudomonas aeruginosa exotoxin A.

    PubMed Central

    Yates, Susan P; Merrill, Allan R

    2004-01-01

    Pseudomonas aeruginosa produces the virulence factor, ETA (exotoxin A), which catalyses an ADP-ribosyltransferase reaction of its target protein, eEF2 (eukaryotic elongation factor-2). Currently, this protein-protein interaction is poorly characterized and this study was aimed at identifying the contact sites between eEF2 and the catalytic domain of ETA (PE24H, an ETA from P. aeruginosa, a 24 kDa C-terminal fragment containing a His6 tag). Single-cysteine residues were introduced into the toxin at 21 defined surface-exposed sites and labelled with the fluorophore, IAEDANS [5-(2-iodoacetylaminoethylamino)-1-napthalenesulphonic acid]. Fluorescence quenching studies using acrylamide, and fluorescence lifetime and wavelength emission maxima analyses were conducted in the presence and absence of eEF2. Large changes in the microenvironment of the AEDANS [5-(2-aminoethylamino)-1-naphthalenesulphonic acid] probe after eEF2 binding were not observed as dictated by both fluorescence lifetime and wavelength emission maxima values. This supported the proposed minimal contact model, which suggests that only small, discrete contacts occur between these proteins. As dictated by the bimolecular quenching constant (k(q)) for acrylamide, binding of eEF2 with toxin caused the greatest change in acrylamide accessibility (>50%) when the fluorescence label was near the active site or was located within a known catalytic loop. All mutant proteins showed a decrease in accessibility to acrylamide once eEF2 bound, although the relative change varied for each labelled protein. From these data, a low-resolution model of the toxin-eEF2 complex was constructed based on the minimal contact model with the intention of enhancing our knowledge on the mode of inactivation of the ribosome translocase by the Pseudomonas toxin. PMID:14733615

  2. Efficacy of Detergent and Water Versus Bleach for the Disinfection of Direct Contact Ophthalmic Lenses

    PubMed Central

    Abbey, Ashkan M.; Gregori, Ninel Z.; Surapaneni, Krishna; Miller, Darlene

    2014-01-01

    Purpose While manufacturers recommend cleaning ophthalmic lenses with detergent and water and then a specific disinfectant, disinfectants are rarely used in ophthalmic practices. The aim of this pilot study was to evaluate the efficacy of detergent and water versus bleach, a recommended disinfectant, to eliminate common ocular bacteria and viruses from ophthalmic lenses. Methods Three bacterial strains (Staphylococcus epidermidis, Corynebacterium straitum, and methicillin-resistant Staphylococcus aureus (MRSA) and two viral strains (adenovirus and herpes simplex virus (HSV) type-1) were individually inoculated to 20 gonioscopy and laser lenses. Lenses were washed with detergent and water and then disinfected with 10% bleach. All lenses were cultured after inoculation, after detergent and water, and after the bleach. Bacterial cultures in thioglycollate broth were observed for 3 weeks and viral cultures for 2 weeks. The presence of viruses was also detected by multiplex polymerase chain reaction (PCR). Results All 20 lenses inoculated with Staphylococcus epidermidis, Corynebacterium straitum, adenovirus, and HSV-1 showed growth after inoculation, but no growth after detergent/water and after the bleach. All lenses showed positive HSV and adenovirus PCR after inoculation and negative PCR after detergent/water and after bleach. All MRSA contaminated lenses showed growth after inoculation and no growth after detergent and water. However, one lens showed positive growth after bleach. Conclusions Cleaning with detergent and water appeared to effectively eliminate bacteria and viruses from the surface of contaminated ophthalmic lenses. Further studies are warranted to design practical disinfection protocols that minimize lens damage. PMID:24747806

  3. Soil Surface Structure: A key factor for the degree of soil water repellency

    NASA Astrophysics Data System (ADS)

    Ahn, S.; Doerr, S. H.; Douglas, P.; Bryant, R.; Hamlett, C.; McHale, G.; Newton, M.; Shirtcliffe, N.

    2012-04-01

    Despite of considerable efforts, the degree of water repellency has not always been fully explained by chemical property of soil (termed hydrophobicity). That might be because the structure of a soil surface was not considered properly, which is another main factor determining the severity of soil water repellency. Surface structure has only recently been considered in soil science, whilst it has been paid attention for several decades in materials science due to its relevance to industrial applications. In this contribution, comparison of critical contact angles measured on different surface structures (made with glass beads, glass shards and beach sands) is presented and the effect of surface structure on manifestation of soil water repellency is discussed in terms of several different variables such as the individual particles shape, and areal and structural factors of the actual surface.

  4. Hysteretic memory in pH-response of water contact angle on poly(acrylic acid) brushes.

    PubMed

    Yadav, Vivek; Harkin, Adrienne V; Robertson, Megan L; Conrad, Jacinta C

    2016-04-21

    We investigated the pH-dependent response of flat polyacid brushes of varying length and dispersity in the extended brush regime. Our model system consisted of poly(acrylic acid) brushes, which change from hydrophobic and neutral at low pH to hydrophilic and negatively charged at high pH, synthesized on silicon substrates using a grafting-from approach at constant grafting density. We observed three trends in the pH-response: first, the dry brush thickness increased as the pH was increased for brushes above a critical length, and this effect was magnified as the dispersity increased; second, the water contact angle measured at low pH was larger for brushes of greater dispersity; and third, brushes of sufficient dispersity exhibited hysteretic memory behavior in the pH-dependence of the contact angle, in which the contact angle upon increasing and decreasing pH differed. As a consequence, the pKa of the brushes measured upon increasing pH was consistently higher than that measured upon decreasing pH. The observed pH response is consistent with proposed changes in the conformation and charge distribution of the polyelectrolyte brushes that depend on the direction of pH change and the dispersity of the brushes.

  5. Potential risk factors associated with contact dermatitis, lameness, negative emotional state, and fear of humans in broiler chicken flocks.

    PubMed

    Bassler, A W; Arnould, C; Butterworth, A; Colin, L; De Jong, I C; Ferrante, V; Ferrari, P; Haslam, S; Wemelsfelder, F; Blokhuis, H J

    2013-11-01

    The objectives of this study were to 1) identify determinants of poor welfare in commercial broiler chicken flocks by studying the associations between selected resource-based measures (RBM, potential risk factors), such as litter quality and dark period, and animal-based welfare indicators (ABM), such as foot pad dermatitis and lameness, and 2) establish the breadth of effect of a risk factor by determining the range of animal welfare indicators associated with each of the risk factors (i.e., the number of ABM related to a specific RBM). Eighty-nine broiler flocks were inspected in 4 European countries (France, Italy, the United Kingdom, and the Netherlands) in a cross-sectional study. The ABM were contact dermatitis (measured using scores of foot-pad dermatitis and hock burn, respectively), lameness (measured as gait score), fear of humans (measured by the avoidance distance test and the touch test), and negative emotional state (measured using qualitative behavior assessment, QBA). In a first step, risk factors were identified by building a multiple linear regression model for each ABM. Litter quality was identified as a risk factor for contact dermatitis. Length of dark period at 3 wk old (DARK3) was a risk factor for the touch test result. DARK3 and flock age were risk factors for lameness, and the number of different stockmen and DARK3 were risk factors for QBA results. Next, the ABM were grouped according to risk factor and counted. Then, in a second step, associations between the ABM were investigated using common factor analysis. The breadth of a risk factor's effect was judged by combining the number (count) of ABM related to this factor and the strength of association between these ABM. Flock age and DARK3 appeared to affect several weakly correlated ABM, thus indicating a broad range of effects. Our findings suggest that manipulation of the predominant risk factors identified in this study (DARK3, litter quality, and slaughter age) could generate

  6. Contact dermatitis

    MedlinePlus

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

  7. Efficacy of detergent and water versus bleach for disinfection of direct contact ophthalmic lenses.

    PubMed

    Abbey, Ashkan M; Gregori, Ninel Z; Surapaneni, Krishna; Miller, Darlene

    2014-06-01

    Although manufacturers recommend cleaning ophthalmic lenses with detergent and water and then with a specific disinfectant, disinfectants are rarely used in ophthalmic practices. The aim of this pilot study was to evaluate the efficacy of detergent and water versus that of bleach, a recommended disinfectant, to eliminate common ocular bacteria and viruses from ophthalmic lenses. Three bacterial strains (Staphylococcus epidermidis, Corynebacterium straitum, and methicillin-resistant Staphylococcus aureus and 2 viral strains (adenovirus and herpes simplex virus [HSV] type-1) were individually inoculated onto 20 gonioscopy and laser lenses. The lenses were washed with detergent and water and then disinfected with 10% bleach. All the lenses were cultured after inoculation, after washing with detergent and water, and after disinfecting with the bleach. Bacterial cultures in thioglycollate broth were observed for 3 weeks, and viral cultures were observed for 2 weeks. The presence of viruses was also detected by multiplex polymerase chain reaction (PCR). All 20 lenses inoculated with S. epidermidis, C. straitum, adenovirus, and HSV-1 showed growth after inoculation but no growth after washing with detergent/water and after disinfecting with the bleach. All lenses showed positive HSV and adenovirus PCR results after inoculation and negative PCR results after washing with detergent/water and after disinfecting with bleach. All methicillin-resistant S. aureus-contaminated lenses showed growth after inoculation and no growth after washing with detergent and water. However, 1 lens showed positive growth after disinfecting with bleach. Cleaning with detergent and water seemed to effectively eliminate bacteria and viruses from the surface of contaminated ophthalmic lenses. Further studies are warranted to design practical disinfection protocols that minimize lens damage.

  8. Asymmetric Receptor Contact is Required for Tyrosine Autophosphorylation of Fibroblast Growth Factor Receptor in Living Cells

    SciTech Connect

    Bae, J.; Boggon, T; Tomé, F; Mandiyan, V; Lax, I; Schlessinge, J

    2010-01-01

    Tyrosine autophosphorylation of receptor tyrosine kinases plays a critical role in regulation of kinase activity and in recruitment and activation of intracellular signaling pathways. Autophosphorylation is mediated by a sequential and precisely ordered intermolecular (trans) reaction. In this report we present structural and biochemical experiments demonstrating that formation of an asymmetric dimer between activated FGFR1 kinase domains is required for transphosphorylation of FGFR1 in FGF-stimulated cells. Transphosphorylation is mediated by specific asymmetric contacts between the N-lobe of one kinase molecule, which serves as an active enzyme, and specific docking sites on the C-lobe of a second kinase molecule, which serves a substrate. Pathological loss-of-function mutations or oncogenic activating mutations in this interface may hinder or facilitate asymmetric dimer formation and transphosphorylation, respectively. The experiments presented in this report provide the molecular basis underlying the control of transphosphorylation of FGF receptors and other receptor tyrosine kinases.

  9. Activation of the factor XII-driven contact system in Alzheimer’s disease patient and mouse model plasma

    PubMed Central

    Zamolodchikov, Daria; Chen, Zu-Lin; Conti, Brooke A.; Renné, Thomas; Strickland, Sidney

    2015-01-01

    Alzheimer’s disease (AD) is characterized by accumulation of the β-amyloid peptide (Aβ), which likely contributes to disease via multiple mechanisms. Increasing evidence implicates inflammation in AD, the origins of which are not completely understood. We investigated whether circulating Aβ could initiate inflammation in AD via the plasma contact activation system. This proteolytic cascade is triggered by the activation of the plasma protein factor XII (FXII) and leads to kallikrein-mediated cleavage of high molecular-weight kininogen (HK) and release of proinflammatory bradykinin. Aβ has been shown to promote FXII-dependent cleavage of HK in vitro. In addition, increased cleavage of HK has been found in the cerebrospinal fluid of patients with AD. Here, we show increased activation of FXII, kallikrein activity, and HK cleavage in AD patient plasma. Increased contact system activation is also observed in AD mouse model plasma and in plasma from wild-type mice i.v. injected with Aβ42. Our results demonstrate that Aβ42-mediated contact system activation can occur in the AD circulation and suggest new pathogenic mechanisms, diagnostic tests, and therapies for AD. PMID:25775543

  10. Questionnaires in the screening for Schistosoma mansoni infection: a study of socio demographic and water contact variables in four communities in Brazil.

    PubMed

    Lima e Costa, M F; Rocha, R S; Firmo, J O; Guerra, H L; Passos, V A; Katz, N

    1998-01-01

    The use of questionnaires has been recommended for identifying, at a lower cost, individuals at risk for schistosomiasis. In this study, validity of information obtained by questionnaire in the screening for Schistosoma mansoni infection was assessed in four communities in the State of Minas Gerais, Brazil. Explanatory variables were water contact activities, sociodemographic characteristics and previous treatment for schistosomiasis. From 677, 1474, 766 and 3290 individuals eligible for stool examination in the communities, 89 to 97% participated in the study. The estimated probability of individuals to be infected, if they have all characteristics identified as independently associated with S.mansoni infection, varied from 15% in Canabrava, to 42% in Belo Horizonte, 48% in Comercinho and 80% in São José do Acácio. Our results do not support the hypothesis that a same questionnaire on risk factors could be used in screening for S.mansoni infection in different communities.

  11. Risk factors associated with the choice to drink bottled water and tap water in rural Saskatchewan.

    PubMed

    McLeod, Lianne; Bharadwaj, Lalita; Waldner, Cheryl

    2014-01-30

    A cross-sectional study investigated risk factors associated with choices to drink bottled water and tap water in rural Saskatchewan. Of 7,500 anonymous postal questionnaires mailed out, 2,065 responses were analyzed using generalized linear mixed models. Those who reported a water advisory (p < 0.001) or living in the area for £10 years (p = 0.01) were more likely to choose bottled water. Those who reported tap water was not safe to drink were more likely to choose bottled water, an effect greater for those who had no aesthetic complaints (p ≤ 0.001), while those with aesthetic complaints were more likely to choose bottled water if they believed the water was safe (p < 0.001). Respondents who treated their water and did not use a community supply were more likely to choose bottled water (p < 0.001), while those who did not treat their water were more likely to choose bottled water regardless of whether a community supply was used (p < 0.001). A similar pattern of risk factors was associated with a decreased likelihood of consuming tap water daily; however, the use of a community water supply was not significant. Understanding the factors involved in drinking water choices could inform public health education efforts regarding water management in rural areas.

  12. Risk Factors Associated with the Choice to Drink Bottled Water and Tap Water in Rural Saskatchewan

    PubMed Central

    McLeod, Lianne; Bharadwaj, Lalita; Waldner, Cheryl

    2014-01-01

    A cross-sectional study investigated risk factors associated with choices to drink bottled water and tap water in rural Saskatchewan. Of 7,500 anonymous postal questionnaires mailed out, 2,065 responses were analyzed using generalized linear mixed models. Those who reported a water advisory (p < 0.001) or living in the area for ≤10 years (p = 0.01) were more likely to choose bottled water. Those who reported tap water was not safe to drink were more likely to choose bottled water, an effect greater for those who had no aesthetic complaints (p ≤ 0.001), while those with aesthetic complaints were more likely to choose bottled water if they believed the water was safe (p < 0.001). Respondents who treated their water and did not use a community supply were more likely to choose bottled water (p < 0.001), while those who did not treat their water were more likely to choose bottled water regardless of whether a community supply was used (p < 0.001). A similar pattern of risk factors was associated with a decreased likelihood of consuming tap water daily; however, the use of a community water supply was not significant. Understanding the factors involved in drinking water choices could inform public health education efforts regarding water management in rural areas. PMID:24487453

  13. Calculation of the Q factor for case 2 waters

    NASA Astrophysics Data System (ADS)

    Shimwell, Susan J.; Wernand, Marcel R.; Boxall, Simon R.

    1997-02-01

    An intensive data collection campaign has been conducted in the coastal waters of the southern North Sea during which a variety of marine optical parameters have ben measured. This has enabled the angular distribution factor of spectral radiance or Q factor to be calculated from in situ measurements. The Q factor relates upwelled spectral radiance to upwelled spectral irradiance and its precise determination is of importance in ocean color remote sensing. Previous modeling studies, often based on the optical properties of case I waters, have proposed a value of 5 for Q. However, this study suggest that more turbid coastal waters may approach the Lambertian case of Q close to (pi) .

  14. Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges

    PubMed Central

    Prest, Emmanuelle I.; Hammes, Frederik; van Loosdrecht, Mark C. M.; Vrouwenvelder, Johannes S.

    2016-01-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order

  15. Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges.

    PubMed

    Prest, Emmanuelle I; Hammes, Frederik; van Loosdrecht, Mark C M; Vrouwenvelder, Johannes S

    2016-01-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order

  16. Predisposing Risk Factors for Non-Contact ACL Injuries in Military Subjects

    DTIC Science & Technology

    2011-01-01

    Purpose The goal of this study was to document the incidence of anterior cruciate ligament (ACL) tears and possible risk factors for these injuries in a...III. Keywords Knee ACL Notch width Notch width index BMI Introduction Anterior cruciate ligament (ACL) tears are extremely common in...NOTES 14. ABSTRACT Purpose The goal of this study was to document the incidence of anterior cruciate ligament (ACL) tears and possible risk factors

  17. Polymer Electrolyte Fuel Cells Membrane Hydration by Direct Liquid Water Contact

    SciTech Connect

    Wilson, M.S.; Zawodzinski, C.; Gottesfeld, S.

    1998-11-01

    An effective means of providing direct liquid hydration of the membrane tends to improve performance particularly of cells with thicker membranes or at elevated temperatures. Supplying the water to the membrane from the anode flow-field through the anode backing via wicks would appear to have advantages over delivering the water through the thickness of the membrane with regards to the uniformity and stability of the supply and the use of off-the-shelf membranes or MEAs. In addition to improving cell performance, an important contribution of direct liquid hydration approaches may be that the overall fuel cell system becomes simpler and more effective. The next steps in the evolution of this approach are a demonstration of the effectiveness of this technique with larger active area cells as well as the implementation of an internal flow-field water reservoir (to eliminate the injection method). Scale-up to larger cell sizes and the use of separate water channels within the anode flow-field is described.

  18. Geomorphic and biophysical factors affecting water tracks in northern Alaska

    NASA Astrophysics Data System (ADS)

    Trochim, E. D.; Jorgenson, M. T.; Prakash, A.; Kane, D. L.

    2016-03-01

    A better understanding of water movement on hillslopes in Arctic environments is necessary for evaluating the effects of climate variability. Drainage networks include a range of features that vary in transport capacity from rills to water tracks to rivers. This research focuses on describing and classifying water tracks, which are saturated linear-curvilinear stripes that act as first-order pathways for transporting water off of hillslopes into valley bottoms and streams. Multiple factor analysis was used to develop five water tracks classes based on their geomorphic, soil, and vegetation characteristics. The water track classes were then validated using conditional inference trees, to verify that the classes were repeatable. Analysis of the classes and their characteristics indicate that water tracks cover a broad spectrum of patterns and processes primarily driven by surficial geology. This research demonstrates an improved approach to quantifying water track characteristics for specific areas, which is a major step toward understanding hydrological processes and feedbacks within a region.

  19. Sediment contact tests as a tool for the assessment of sediment quality in German waters.

    PubMed

    Feiler, Ute; Höss, Sebastian; Ahlf, Wolfgang; Gilberg, Daniel; Hammers-Wirtz, Monika; Hollert, Henner; Meller, Michael; Neumann-Hensel, Helga; Ottermanns, Richard; Seiler, Thomas-Benjamin; Spira, Denise; Heininger, Peter

    2013-01-01

    A sediment contact test (SCT) battery consisting of five ecotoxicological test systems was applied to 21 native freshwater sediments characterized by a broad variety of geochemical properties and anthropogenic contamination. Higher plants (Myriophyllum aquaticum), nematodes (Caenorhabditis elegans), oligochaetes (Lumbriculus variegatus), zebrafish embryos (Danio rerio), and bacteria (Arthrobacter globiformis), representing various trophic levels and exposure pathways, were used as test organisms. The test battery detected sediment toxicity caused by anthropogenic pollution, whereas the various tests provided site-specific, nonredundant information to the overall toxicity assessment. Based on the toxicity pattern derived from the test battery, the sediments were classified according to a newly proposed classification system for sediment toxicity assessment. The SCT-derived classification generally agreed well with the application of consensus-based sediment quality guidelines (SQGs), especially with regard to sediments with high toxic potential. For sediments with low to medium toxic potential, the SQGs often underestimated the toxicity that was detected by the SCTs, underpinning the need for toxicity tests in sediment quality assessment. Copyright © 2012 SETAC.

  20. Evaluation of susceptibility of polymer and rubber materials intended into contact with drinking water on biofilm formation

    PubMed

    Szczotko, Maciej; Stankiewicz, Agnieszka; Jamsheer-Bratkowska, Małgorzata

    Plumbing materials in water distribution networks and indoor installations are constantly evolving. The application of new, more economical solutions with plastic materials eliminates the corrosion problems, however, do not fully protect the consumer against secondary microbial contamination of water intended for human consumption caused by the presence of a biofilm on the inner surface of materials applied. National Institute of Public Health - National Institute of Hygiene conducts research aimed at a comprehensive assessment of this type of materials, resulting their further marketing authorization in Poland. Evaluation and comparison of polymer and rubber materials intended to contact with water for the susceptibility to biofilm formation. Plastic materials (polyethylene, polypropylene, polyvinyl chloride) and rubber compounds (EPDM, NBR), from different manufacturers were evaluated. The study was carried out on 37 samples, which were divided into groups according to the material of which they were made. The testing was conducted according to the method based on conditions of dynamic flow of tap water. The level of bioluminescence in swabs taken from the surface of the tested materials was investigated with a luminometer. Evaluation of plastic materials does not show major objections in terms of hygienic assessment. All materials met the evaluation criteria established for methodology used. In case of rubber compounds, a substantial part clearly exceeded the limit values, which resulted in their negative assessment and elimination of these materials from domestic market. High susceptibility to the formation of biofilm in the group of products made of rubber compounds has been demonstrated. Examined plastic materials, except for several cases, do not revealed susceptibility to biofilm formation, but application of plastics for distribution of water intended for human consumption does not fully protect water from secondary, microbiological contamination. Complete

  1. Vancomycin-resistant enterococcus (VRE) transmission and risk factors in contacts of VRE carriers.

    PubMed

    Kaki, Reham; Yu, Yang; O'Neill, Cindy; Lee, Christine; Mertz, Dominik

    2014-07-01

    During a 2-year period, the vancomycin-resistant enterococcus (VRE) acquisition rate was 10.9% (40/368) in patients who had shared a room with a newly detected VRE carrier. Exposure to vancomycin and to anti-anaerobic antibiotics were identified as independent risk factors for VRE acquisition. Sensitivity of the first rectal VRE screening was less than 50%.

  2. Which Extrinsic and Intrinsic Factors are Associated with Non-Contact Injuries in Adult Cricket Fast Bowlers?

    PubMed

    Olivier, Benita; Taljaard, Tracy; Burger, Elaine; Brukner, Peter; Orchard, John; Gray, Janine; Botha, Nadine; Stewart, Aimee; Mckinon, Warrick

    2016-01-01

    The high prevalence of injury amongst cricket fast bowlers exposes a great need for research into the risk factors associated with injury. Both extrinsic (environment-related) and intrinsic (person-related) risk factors are likely to be implicated within the high prevalence of non-contact injury amongst fast bowlers in cricket. Identifying and defining the relative importance of these risk factors is necessary in order to optimize injury prevention efforts. The objective of this review was to assess and summarize the scientific literature related to the extrinsic and intrinsic factors associated with non-contact injury inherent to adult cricket fast bowlers. A systematic review was performed in compliance with the PRISMA guidelines. This review considered both experimental and epidemiological study designs. Studies that included male cricket fast bowlers aged 18 years or above, from all levels of play, evaluating the association between extrinsic/intrinsic factors and injury in fast bowlers were considered for inclusion. The three-step search strategy aimed at finding both published and unpublished studies from all languages. The searched databases included MEDLINE via PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Cochrane Controlled Trials Register in the Cochrane Library, Physiotherapy Evidence Database (PEDro), ProQuest 5000 International, ProQuest Health and Medical Complete, EBSCO MegaFile Premier, Science Direct, SPORTDiscus with Full Text and SCOPUS (prior to 28 April 2015). Initial keywords used were 'cricket', 'pace', 'fast', 'bowler', and 'injury'. Papers which fitted the inclusion criteria were assessed by two independent reviewers for methodological validity prior to inclusion in the review using standardized critical appraisal instruments from the Joanna Briggs Institute Meta Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI). A total of 16 studies were determined to be suitable for inclusion in this

  3. Investigating Factors that Affect Dissolved Oxygen Concentration in Water

    ERIC Educational Resources Information Center

    Jantzen, Paul G.

    1978-01-01

    Describes activities that demonstrate the effects of factors such as wind velocity, water temperature, convection currents, intensity of light, rate of photosynthesis, atmospheric pressure, humidity, numbers of decomposers, presence of oxidizable ions, and respiration by plants and animals on the dissolved oxygen concentration in water. (MA)

  4. Investigating Factors that Affect Dissolved Oxygen Concentration in Water

    ERIC Educational Resources Information Center

    Jantzen, Paul G.

    1978-01-01

    Describes activities that demonstrate the effects of factors such as wind velocity, water temperature, convection currents, intensity of light, rate of photosynthesis, atmospheric pressure, humidity, numbers of decomposers, presence of oxidizable ions, and respiration by plants and animals on the dissolved oxygen concentration in water. (MA)

  5. Extrinsic and intrinsic factors associated with non-contact injury in adult pace bowlers: a systematic review protocol.

    PubMed

    Olivier, Benita; Stewart, Aimee; Taljaard, Tracy; Burger, Elaine; Brukner, Peter; Orchard, John; Gray, Janine; Botha, Nadine; Mckinon, Warrick

    2015-01-01

    Review question: which extrinsic and intrinsic factors are associated with non-contact injury in adult cricket pace bowlers?Review objective: the objective of this review is to determine the extrinsic and intrinsic factors associated with non-contact injury in adult pace bowlers. Cricket is generally considered to be a sport of low injury risk compared to other sports. In cricket, the pace bowler strives towards the adoption of a bowling technique with a relatively low injury threat that will, at the same time, allow for a fast (>120km/hr) and accurate delivery to the opposing batsman. However, of all the various roles of the cricket player, the pace bowler has the highest risk of injury, especially for low back and lower limb (lower quarter) injury. The reason for this high risk of injury is due to the inherent, high-load biomechanical nature of the pace bowling action. The high prevalence of injury amongst pace bowlers highlights the great need for research into factors associated with injury.Both extrinsic and intrinsic factors work in combination to predispose the bowler to injury. Extrinsic or environment-related factors include bowling workload (the numbers of overs a bowler bowls), player position (first, second or third change) and time of play (morning or afternoon). A high bowling workload has been linked with a higher risk of injury in pace bowlers. Foster et al. found in an observational study that bowling too many overs in a single spell or bowling too many spells may increase the pace bowler's risk of sustaining a low back injury. In another observational study, Dennis et al. found that an exceptionally high bowling workload as well as an uncommonly low bowling workload is associated with injury risk. The major extrinsic factors for bowling injury identified by Orchard et al. are a high number of match overs bowled in the previous week, number of days of play and bowling second (batting first) in a match. Extrinsic factors are known to make the bowler

  6. The Denudation Of Oahu, Hawaii USA By Ground And Surface Waters: The Effects Of Climate, Soil Thickness, And Water Contact Times On Ocean Island Erosion

    NASA Astrophysics Data System (ADS)

    Nelson, S. T.; Tingey, D. G.

    2011-12-01

    Access, size, basalt as the dominant bedrock, and climate variation (rainfall varies by 10x) make Oahu, Hawaii, USA an ideal locality for investigating chemical weathering driven denudation rates. New and compiled surface and groundwater solute data permit calculation of mass balances for solutes from Oahu, revealing that groundwater solute fluxes dominate surface water by a factor of 3 to 12, neglecting if biogenic silica removal by streams. Weathering reactions consistent with the observed mineralogy of Oahu soils and the calculated mineralogy of shield-forming tholeiitic basalts permit denudation rates to be partitioned between dissolved and suspended loads where long term erosion via streams and soil formation rates are assumed to be in a steady state. Aerially averaged denudation rates, indexed to the leaching of SiO2, vary from 0.016 to 0.063 m/ka, with about 70% of denudation due to dissolved fluxes. Thus, groundwater appears to be the single most important source of mass flux to the ocean from ocean islands. Dry regions of Oahu have distinctly lower denudation rates, and areas with thick soil profiles have suppressed solute loads in streams because laterites and subjacent saprolites have already been largely depleted in mobile elements. However, systematic differences also exist due to different contact times between groundwater and aquifer materials. The short, shallow circulation of stream base flows permits less extensive reaction with basalt resulting in lower solute loads even in areas where thick soils are largely absent. In addition to larger total water fluxes, deep groundwaters exhibit elevated solute loads across Oahu. Indexing denudation in basaltic terranes to dissolved SiO2, a minor component in seawater, rather than other solutes leads to improved estimates of weathering rates in ocean islands. Other approaches require correction for the atmospheric depositions of sea salts based on Cl- abundances in waters that are assumed to derive solely

  7. Risk factors and prevention strategies of non-contact anterior cruciate ligament injuries.

    PubMed

    Laible, Catherine; Sherman, Orrin H

    2014-01-01

    In recent years, the number of women playing sports has increased significantly. The passage of Title IX in 1972 had a significant effect in encouraging female participation in sports. This increase in women's sports participation also led to a rise in noncontact anterior cruciate ligament (ACL) injuries. As ACL injuries in young female athletes have be- come a public health issue, much research has been done on risk factors and prevention strategies.

  8. Drag Moderation by the Melting of an Ice Surface in Contact with Water

    NASA Astrophysics Data System (ADS)

    Vakarelski, Ivan U.; Chan, Derek Y. C.; Thoroddsen, Sigurdur T.

    2015-07-01

    We report measurements of the effects of a melting ice surface on the hydrodynamic drag of ice-shell-metal-core spheres free falling in water at a Reynolds of number Re ˜2 ×104- 3 ×105 and demonstrate that the melting surface induces the early onset of the drag crisis, thus reducing the hydrodynamic drag by more than 50%. Direct visualization of the flow pattern demonstrates the key role of surface melting. Our observations support the hypothesis that the drag reduction is due to the disturbance of the viscous boundary layer by the mass transfer from the melting ice surface.

  9. Drag Moderation by the Melting of an Ice Surface in Contact with Water.

    PubMed

    Vakarelski, Ivan U; Chan, Derek Y C; Thoroddsen, Sigurdur T

    2015-07-24

    We report measurements of the effects of a melting ice surface on the hydrodynamic drag of ice-shell-metal-core spheres free falling in water at a Reynolds of number Re~2×10^{4}-3×10^{5} and demonstrate that the melting surface induces the early onset of the drag crisis, thus reducing the hydrodynamic drag by more than 50%. Direct visualization of the flow pattern demonstrates the key role of surface melting. Our observations support the hypothesis that the drag reduction is due to the disturbance of the viscous boundary layer by the mass transfer from the melting ice surface.

  10. Real-time Non-contact Millimeter Wave Characterization of Water-Freezing and Ice-Melting Dynamics

    SciTech Connect

    Sundaram, S. K.; Woskov, Paul P.

    2008-11-12

    We applied millimeter wave radiometry for the first time to monitor water-freezing and ice-melting dynamics in real-time non-contact. The measurements were completed at a frequency of 137 GHz. Small amounts (about 2 mL) of freshwater or saltwater were frozen over a Peltier cooler and the freezing and melting sequence was recorded. Saltwater was prepared in the laboratory that contained 3.5% of table salt to simulate the ocean water. The dynamics of freezing-melting was observed by measuring the millimeter wave temperature as well as the changes in the ice or water surface reflectivity and position. This was repeated using large amounts of freshwater and saltwater (800 mL) mimicking glaciers. Millimeter wave surface level fluctuations indicated as the top surface melted, the light ice below floated up indicating lower surface temperature until the ice completely melted. Our results are useful for remote sensing and tracking temperature for potentially large-scale environmental applications, e.g., global warming.

  11. Chemical characterization of blue stains in domestic fixtures in contact with drinking water.

    PubMed

    Letelier, María V; Lagos, Gustavo E; Reyes, Arturo

    2008-04-01

    Bluish green staining in domestic fixtures was observed in three to 9-year-old houses in the city of Talca, located 256 km. south of Santiago, the capital of Chile. The houses contained copper pipes which were exposed to soft well water, with low pH and low buffer capacity. The aim of this paper is to establish the chemical composition of the stains and to determine the conditions by which they were formed. X-ray diffraction analysis of the stains revealed the presence of malachite, a copper compound that caused green coloring in kettles and water boilers. Dioptase, which is deep green in coloring, was identified in a bathtub tile. In one house, where blue stains were found in a toilet bowl, the presence of chrysocolla was suggested by means of X-ray fluorescence. In the field conditions studied it was concluded that the bluish green stains in bathroom home appliances were generated by the precipitation of copper compounds in places were leakages occur.

  12. Contact Forces between TiO2 Nanoparticles Governed by an Interplay of Adsorbed Water Layers and Roughness.

    PubMed

    Laube, Jens; Salameh, Samir; Kappl, Michael; Mädler, Lutz; Colombi Ciacchi, Lucio

    2015-10-20

    Interparticle forces govern the mechanical behavior of granular matter and direct the hierarchical assembling of nanoparticles into supramolecular structures. Understanding how these forces change under different ambient conditions would directly benefit industrial-scale nanoparticle processing units such as filtering and fluidization. Here we rationalize and quantify the contributions of dispersion, capillary, and solvation forces between hydrophilic TiO2 nanoparticles with sub-10 nm diameter and show that the humidity dependence of the interparticle forces is governed by a delicate interplay between the structure of adsorbed water layers and the surface roughness. All-atom molecular dynamics modeling supported by force-spectroscopy experiments reveals an unexpected decrease in the contact forces at increasing humidity for nearly spherical particles, while the forces between rough particles are insensitive to strong humidity changes. Our results also frame the limits of applicability of discrete solvation and continuum capillary theories in a regime where interparticle forces are dominated by the molecular nature of surface adsorbates.

  13. Direct-contact condensers for open-cycle OTEC applications: Model validation with fresh water experiments for structured packings

    SciTech Connect

    Bharathan, D.; Parsons, B.K.; Althof, J.A.

    1988-10-01

    The objective of the reported work was to develop analytical methods for evaluating the design and performance of advanced high-performance heat exchangers for use in open-cycle thermal energy conversion (OC-OTEC) systems. This report describes the progress made on validating a one-dimensional, steady-state analytical computer of fresh water experiments. The condenser model represents the state of the art in direct-contact heat exchange for condensation for OC-OTEC applications. This is expected to provide a basis for optimizing OC-OTEC plant configurations. Using the model, we examined two condenser geometries, a cocurrent and a countercurrent configuration. This report provides detailed validation results for important condenser parameters for cocurrent and countercurrent flows. Based on the comparisons and uncertainty overlap between the experimental data and predictions, the model is shown to predict critical condenser performance parameters with an uncertainty acceptable for general engineering design and performance evaluations. 33 refs., 69 figs., 38 tabs.

  14. Direct-contact condensers for open-cycle OTEC applications: Model validation with fresh water experiments for structured packings

    NASA Astrophysics Data System (ADS)

    Bharathan, D.; Parsons, B. K.; Althof, J. A.

    1988-10-01

    The objective of the reported work was to develop analytical methods for evaluating the design and performance of advanced high-performance heat exchangers for use in open-cycle thermal energy conversion (OC-OTEC) systems. This report describes the progress made on validating a one-dimensional, steady-state analytical computer of fresh water experiments. The condenser model represents the state of the art in direct-contact heat exchange for condensation for OC-OTEC applications. This is expected to provide a basis for optimizing OC-OTEC plant configurations. Using the model, we examined two condenser geometries, a cocurrent and a countercurrent configuration. This report provides detailed validation results for important condenser parameters for cocurrent and countercurrent flows. Based on the comparisons and uncertainty overlap between the experimental data and predictions, the model is shown to predict critical condenser performance parameters with an uncertainty acceptable for general engineering design and performance evaluations.

  15. The Process and Reason of the Change of Oil-Water Contact of Shahejie Formation in BZ25-1 Oilfield

    NASA Astrophysics Data System (ADS)

    Cong, F.; Liu, J.

    2015-12-01

    Due to the influence of Neo-tectonic movement, the Shahejie reservoirs in Bohai Bay Basin has undergone late-stage transformation and adjustment, causing the oil-water contact to change. Through studying the changing history of oil-water contact, we can better restore petroleum accumulation process and analyze oil distribution pattern. Based on reservoir geochemistry theory and drilling and logging data, grains with oil inclusion was analyzed, and oil-bearing property, organic extracts and biomarkers was used to determine the present and paleo-oil water contact of Shahejie formation in BZ25-1 oilfield. It suggested that the paleo and present oil-water contact in Shahejie formation locates in different depth, and that Shahejie formation has gone through three petroleum charging stages and has also undergone reservoir adjustment. The POWC(paleo-oil-water contact) of E2S2 reservoirs in BZ25-1-5 well and E2S2 reservoirs in BZ25-1-3 well is lower than OWC(present oil-water contact) at least for 9m and at most for 400m, but the POWC of E2S3 reservoirs in BZ25-1-5 well is higher than OWC at least for 20m and at most for 27.5m. The petroleum accumulation process and the reason for oil-water contact adjustment were studied based on burial history, petroleum generation history, fault re-activation rate and petroleum charging history. It suggested that the three petroleum charging stages are Mid-Miocene(11.5Ma), Late Miocene-Pliocene(6.5-3.5Ma) and Quaternary(2.5Ma-present), among which the second~third charging episode is seen as the major petroleum accumulation stage. The re-activeted faults in several different periods not only served as preferential path for petroleum vertical migration, but also caused petroleum leakage through faults. The petroleum leakage mainly occurred in Neo-tectonic movement period(after 3.5Ma), during which petroleum vertically leaked through re-activated faults and migrated to shallow reservoirs or spilled over surface, meanwhile due to constant

  16. Factors affecting sustainability of rural water schemes in Swaziland

    NASA Astrophysics Data System (ADS)

    Peter, Graciana; Nkambule, Sizwe E.

    The Millennium Development Goal (MDG) target to reduce the proportion of people without sustainable access to safe drinking water by the year 2015 has been met as of 2010, but huge disparities exist. Some regions, particularly Sub-Saharan Africa are lagging behind it is also in this region where up to 30% of the rural schemes are not functional at any given time. There is need for more studies on factors affecting sustainability and necessary measures which when implemented will improve the sustainability of rural water schemes. The main objective of this study was to assess the main factors affecting the sustainability of rural water schemes in Swaziland using a Multi-Criteria Analysis Approach. The main factors considered were: financial, social, technical, environmental and institutional. The study was done in Lubombo region. Fifteen functional water schemes in 11 communities were studied. Data was collected using questionnaires, checklist and focused group discussion guide. A total of 174 heads of households were interviewed. Statistical Package for Social Sciences (SPSS) was used to analyse the data and to calculate sustainability scores for water schemes. SPSS was also used to classify sustainability scores according to sustainability categories: sustainable, partially sustainable and non-sustainable. The averages of the ratings for the different sub-factors studied and the results on the sustainability scores for the sustainable, partially sustainable and non-sustainable schemes were then computed and compared to establish the main factors influencing sustainability of the water schemes. The results indicated technical and social factors as most critical while financial and institutional, although important, played a lesser role. Factors which contributed to the sustainability of water schemes were: functionality; design flow; water fetching time; ability to meet additional demand; use by population; equity; participation in decision making on operation and

  17. The contact system contributes to hypotension but not disseminated intravascular coagulation in lethal bacteremia. In vivo use of a monoclonal anti-factor XII antibody to block contact activation in baboons.

    PubMed Central

    Pixley, R A; De La Cadena, R; Page, J D; Kaufman, N; Wyshock, E G; Chang, A; Taylor, F B; Colman, R W

    1993-01-01

    The hypotension and disseminated intravascular coagulation (DIC) in bacteremia is thought to be mediated by the combined actions of cytokines, prostaglandins, and complement. The contact system, via the release of bradykinin and the activation of Factor XI, has been postulated to be contributing to the observed hypotension and DIC. Using a mAb to Factor XII (C6B7), we blocked the activation of the contact system in an established experimental baboon model in which Escherichia coli was infused to produce lethal bacteremia with hypotension. The untreated group (n = 5) displayed contact activation, manifested by a significant decrease in high molecular weight kininogen (HK) and a significant increase in alpha 2 macroglobulin-kallikrein complexes (alpha 2M-Kal). The C6B7-treated group (n = 5) showed an inactivation of Factor XII and the changes in HK and alpha 2M-Kal complexes were prevented. Both groups developed DIC manifested by a decrease in platelet, fibrinogen, and Factor V levels. The untreated group developed irreversible hypotension. The treated group experienced an initial hypotension that was reversed and extended the life of the animals. This study suggests that irreversible hypotension correlates with prolonged activation of the contact system, and specific antibody therapy can modulate both the pathophysiological and biochemical changes. Images PMID:7678610

  18. AFM Study of Surface Nanobubbles on Binary Self-Assembled Monolayers on Ultraflat Gold with Identical Macroscopic Static Water Contact Angles and Different Terminal Functional Groups.

    PubMed

    Song, Bo; Chen, Kun; Schmittel, Michael; Schönherr, Holger

    2016-11-01

    All experimental findings related to surface nanobubbles, such as their pronounced stability and the striking differences of macroscopic and apparent nanoscopic contact angles, need to be addressed in any theory or model of surface nanobubbles. In this work we critically test a recent explanation of surface nanobubble stability and their consequences and contrast this with previously proposed models. In particular, we elucidated the effect of surface chemical composition of well-controlled solid-aqueous interfaces of identical roughness and defect density on the apparent nanoscopic contact angles. Expanding on a previous atomic force microscopy (AFM) study on the systematic variation of the macroscopic wettability using binary self-assembled monolayers (SAMs) on ultraflat template stripped gold (TSG), we assessed here the effect of different surface chemical composition for macroscopically identical static water contact angles. SAMs on TSG with a constant macroscopic water contact angle of 81 ± 2° were obtained by coadsorption of a methyl-terminated thiol and a second thiol with different terminal functional groups, including hydroxy, amino, and carboxylic acid groups. In addition, surface nanobubbles formed by entrainment of air on SAMs of a bromoisobutyrate-terminated thiol were analyzed by AFM. Despite the widely differing surface potentials and different functionality, such as hydrogen bond acceptor or donor, and different dipole moments and polarizability, the nanoscopic contact angles (measured through the condensed phase and corrected for AFM tip broadening effects) were found to be 145 ± 10° for all surfaces. Hence, different chemical functionalities at identical macroscopic static water contact angle do not noticeably influence the apparent nanoscopic contact angle of surface nanobubbles. This universal contact angle is in agreement with recent models that rely on contact line pinning and the equilibrium of gas outflux due to the Laplace pressure and

  19. Antimicrobial Contact-Active Oligo(2-oxazoline)s-Grafted Surfaces for Fast Water Disinfection at the Point-of-Use.

    PubMed

    Correia, Vanessa G; Ferraria, Ana M; Pinho, Mariana G; Aguiar-Ricardo, Ana

    2015-12-14

    Water is one of the most valuable resources today and its purity is crucial to health and society well-being. The access to safe drinking water is decreasing in the world, which can have a huge socio-economic impact especially in developing countries, more prone to water-associated diseases. The goal of this work was to develop an innovative, fast, and cost-effective 3D material capable of decontaminating water. We have used an eco-friendly strategy, combining plasma surface activation and supercritical fluid technology to produce, for the first time, a 2-oxazoline-grafted 3D surface with broad-spectrum contact-active antimicrobial properties. Oligo(2-methyl-2-oxazoline) quaternized with N,N-dimethyldodecylamine and grafted to a chitosan (CHT) scaffold (CHT-OMetOx-DDA) efficiently and quickly (<3 min) killed >99.999% of Staphylococcus aureus and Escherichia coli cells upon direct contact and avoided bacterial adhesion to the materials surface, which is important for the prevention of biofilm formation. As a proof of concept, CHT-OMetOx-DDA scaffold was demonstrated to be suitable for water purification efficiently killing the microorganisms present in different water samples within minutes of contact and without leaching to the water. Additionally, we report for the first time a new method to clearly distinguish two mechanisms of action of bioactive surfaces: contact-active and releasing systems.

  20. Intrinsic risk factors of non-contact quadriceps and hamstring strains in soccer: a prospective study of 100 professional players.

    PubMed

    Fousekis, Konstantinos; Tsepis, Elias; Poulmedis, Peter; Athanasopoulos, Spyros; Vagenas, George

    2011-07-01

    To identify the intrinsic risk factors of non-contact strains in the hamstrings and quadriceps muscles of professional soccer players via a cohort prospective design. A total of 100 professional soccer players (aged 19.4-27.8 years) from four professional teams underwent a composite musculoskeletal assessment at preseason. Intrinsic risk factors included dichotomies of asymmetries in muscle strength, flexibility, proprioception, anthropometry and knee joint stability, and of previous injuries. Muscle strains were prospectively monitored during the subsequent season using questionnaires. The data were analysed via binary logistic regression. Thirty-eight percent of the players sustained one or more lower-extremity muscle strains. Sixteen (42.1 %) and seven (18.4 %) of them were clinically diagnosed as having non-contact muscle strains at their hamstrings and quadriceps, respectively. Players with eccentric hamstring strength asymmetries (OR=3.88; 95% CI 1.13 to 13.23), functional leg length asymmetries (OR=3.80; 95% CI 1.08 to 13.33) and no previous hamstrings injuries (OR=0.15; 95% CI 0.029 to 0.79) were at greater risk of sustaining a hamstring muscle strain. Players with eccentric strength (OR=5.01; 95% CI 0.92 to 27.14) and flexibility asymmetries (OR=4.98; 95% CI 0.78 to 31.80) in their quadriceps as well as heavier (OR=10.70; 95% CI 0.73 to 156.37) and shorter players (OR=0.08; 95% CI 0.00 to 1.35) were at greater risk of sustaining a strain in this muscle group. Professional soccer players with functional asymmetries possess a higher risk of sustaining hamstring strains. Previous injury seems not to constitute a risk factor. The systematic isokinetic evaluation of the lower extremities during the preseason period can provide therapists and trainers with valuable data regarding the predictive elements of non-contact hamstring strains in professional soccer players.

  1. Application of factor analysis to the water quality in reservoirs

    NASA Astrophysics Data System (ADS)

    Silva, Eliana Costa e.; Lopes, Isabel Cristina; Correia, Aldina; Gonçalves, A. Manuela

    2017-06-01

    In this work we present a Factor Analysis of chemical and environmental variables of the water column and hydro-morphological features of several Portuguese reservoirs. The objective is to reduce the initial number of variables, keeping their common characteristics. Using the Factor Analysis, the environmental variables measured in the epilimnion and in the hypolimnion, together with the hydromorphological characteristics of the dams were reduced from 63 variables to only 13 factors, which explained a total of 83.348% of the variance in the original data. After performing rotation using the Varimax method, the relations between the factors and the original variables got clearer and more explainable, which provided a Factor Analysis model for these environmental variables using 13 varifactors: Water quality and distance to the source, Hypolimnion chemical composition, Sulfite-reducing bacteria and nutrients, Coliforms and faecal streptococci, Reservoir depth, Temperature, Location, among other factors.

  2. Factors affecting water quality in the releases from hydropower reservoirs

    SciTech Connect

    Ruane, R.J.; Hauser, G.E. )

    1990-01-01

    Typical water quality concerns with releases from hydropower reservoirs include low dissolved oxygen, inappropriate temperature for downstream uses, supersaturation of total dissolved gases, and water quality constituents associated with low dissolved oxygen. Except for supersaturation of total dissolved gases, which is usually caused by by-passing turbines and spilling water, all of these concerns are related to the limnology of the upstream reservoir. Various limnological factors affect water quality, particularly dissolved oxygen (DO) in turbine releases. This paper describes three groups of reservoirs, thermal stratification characteristics for each group, DO effects for each group, the main factors that affect DO in TVA turbine releases, and other water quality constituents that are related to low DO.

  3. Identification and assessment of potential water quality impact factors for drinking-water reservoirs.

    PubMed

    Gu, Qing; Deng, Jinsong; Wang, Ke; Lin, Yi; Li, Jun; Gan, Muye; Ma, Ligang; Hong, Yang

    2014-06-10

    Various reservoirs have been serving as the most important drinking water sources in Zhejiang Province, China, due to the uneven distribution of precipitation and severe river pollution. Unfortunately, rapid urbanization and industrialization have been continuously challenging the water quality of the drinking-water reservoirs. The identification and assessment of potential impacts is indispensable in water resource management and protection. This study investigates the drinking water reservoirs in Zhejiang Province to better understand the potential impact on water quality. Altogether seventy-three typical drinking reservoirs in Zhejiang Province encompassing various water storage levels were selected and evaluated. Using fifty-two reservoirs as training samples, the classification and regression tree (CART) method and sixteen comprehensive variables, including six sub-sets (land use, population, socio-economy, geographical features, inherent characteristics, and climate), were adopted to establish a decision-making model for identifying and assessing their potential impacts on drinking-water quality. The water quality class of the remaining twenty-one reservoirs was then predicted and tested based on the decision-making model, resulting in a water quality class attribution accuracy of 81.0%. Based on the decision rules and quantitative importance of the independent variables, industrial emissions was identified as the most important factor influencing the water quality of reservoirs; land use and human habitation also had a substantial impact on water quality. The results of this study provide insights into the factors impacting the water quality of reservoirs as well as basic information for protecting reservoir water resources.

  4. Evaluating the reliability of equilibrium dissolution assumption from residual gasoline in contact with water saturated sands

    NASA Astrophysics Data System (ADS)

    Lekmine, Greg; Sookhak Lari, Kaveh; Johnston, Colin D.; Bastow, Trevor P.; Rayner, John L.; Davis, Greg B.

    2017-01-01

    Understanding dissolution dynamics of hazardous compounds from complex gasoline mixtures is a key to long-term predictions of groundwater risks. The aim of this study was to investigate if the local equilibrium assumption for BTEX and TMBs (trimethylbenzenes) dissolution was valid under variable saturation in two dimensional flow conditions and evaluate the impact of local heterogeneities when equilibrium is verified at the scale of investigation. An initial residual gasoline saturation was established over the upper two-thirds of a water saturated sand pack. A constant horizontal pore velocity was maintained and water samples were recovered across 38 sampling ports over 141 days. Inside the residual NAPL zone, BTEX and TMBs dissolution curves were in agreement with the TMVOC model based on the local equilibrium assumption. Results compared to previous numerical studies suggest the presence of small scale dissolution fingering created perpendicular to the horizontal dissolution front, mainly triggered by heterogeneities in the medium structure and the local NAPL residual saturation. In the transition zone, TMVOC was able to represent a range of behaviours exhibited by the data, confirming equilibrium or near-equilibrium dissolution at the scale of investigation. The model locally showed discrepancies with the most soluble compounds, i.e. benzene and toluene, due to local heterogeneities exhibiting that at lower scale flow bypassing and channelling may have occurred. In these conditions mass transfer rates were still high enough to fall under the equilibrium assumption in TMVOC at the scale of investigation. Comparisons with other models involving upscaled mass transfer rates demonstrated that such approximations with TMVOC could lead to overestimate BTEX dissolution rates and underestimate the total remediation time.

  5. Evaluating the reliability of equilibrium dissolution assumption from residual gasoline in contact with water saturated sands.

    PubMed

    Lekmine, Greg; Sookhak Lari, Kaveh; Johnston, Colin D; Bastow, Trevor P; Rayner, John L; Davis, Greg B

    2017-01-01

    Understanding dissolution dynamics of hazardous compounds from complex gasoline mixtures is a key to long-term predictions of groundwater risks. The aim of this study was to investigate if the local equilibrium assumption for BTEX and TMBs (trimethylbenzenes) dissolution was valid under variable saturation in two dimensional flow conditions and evaluate the impact of local heterogeneities when equilibrium is verified at the scale of investigation. An initial residual gasoline saturation was established over the upper two-thirds of a water saturated sand pack. A constant horizontal pore velocity was maintained and water samples were recovered across 38 sampling ports over 141days. Inside the residual NAPL zone, BTEX and TMBs dissolution curves were in agreement with the TMVOC model based on the local equilibrium assumption. Results compared to previous numerical studies suggest the presence of small scale dissolution fingering created perpendicular to the horizontal dissolution front, mainly triggered by heterogeneities in the medium structure and the local NAPL residual saturation. In the transition zone, TMVOC was able to represent a range of behaviours exhibited by the data, confirming equilibrium or near-equilibrium dissolution at the scale of investigation. The model locally showed discrepancies with the most soluble compounds, i.e. benzene and toluene, due to local heterogeneities exhibiting that at lower scale flow bypassing and channelling may have occurred. In these conditions mass transfer rates were still high enough to fall under the equilibrium assumption in TMVOC at the scale of investigation. Comparisons with other models involving upscaled mass transfer rates demonstrated that such approximations with TMVOC could lead to overestimate BTEX dissolution rates and underestimate the total remediation time.

  6. Prevalence and risk factors of contact dermatitis among clothing manufacturing employees in Beijing: A cross-sectional study.

    PubMed

    Chen, Yu-Xin; Cheng, Hai-Yan; Li, Lin-Feng

    2017-03-01

    Little is known about the epidemiology of contact dermatitis (CD) in the Chinese clothing industry. This study aimed to investigate the prevalence and some risk factors of contact dermatitis among clothing manufacturing employees in Beijing.This cross-sectional study was conducted by interview using self-administered questionnaires and skin examination between May and August in 2016. Five-hundred twenty-nine employees who had worked at sewing, ironing, and as managers at 12 clothing manufacturing factories were studied.The overall 1-year prevalence of CD among the clothing employees was 28.5% (151/529 employees), with significantly higher prevalence among ironing workers (50%) and sewers (31.7%) compared with managers (12.7%; P < 0.001, n = 529). A significant association was noticed between the 1-year prevalence of CD and types of occupation (sewers and ironing workers versus managers, respectively), exposure to garment materials (leather and feather), dry skin, allergic rhinitis, age, and smoking.Among employees in Chinese clothing industry, sewers and ironing workers had a higher 1-year prevalence of CD than managers. It is noteworthy that exposure to leather and feather materials and the types of manual work are associated with CD, as well as dry skin and allergic rhinitis.

  7. Platelet-activating Factor Receptor Initiates Contact of Acinetobacter baumannii Expressing Phosphorylcholine with Host Cells

    PubMed Central

    Smani, Younes; Docobo-Pérez, Fernando; López-Rojas, Rafael; Domínguez-Herrera, Juan; Ibáñez-Martínez, José; Pachón, Jerónimo

    2012-01-01

    Adhesion is an initial and important step in Acinetobacter baumannii causing infections. However, the exact molecular mechanism of such a step between A. baumannii and the host cells remains unclear. Here, we demonstrated that the phosphorylcholine (ChoP)-containing outer membrane protein of A. baumannii binds to A549 cells through platelet-activating factor receptor (PAFR), resulting in activation of G protein and intracellular calcium. Upon A. baumannii expressing ChoP binding to PAFR, clathrin and β-arrestins, proteins involved in the direction of the vacuolar movement, are activated during invasion of A. baumannii. PAFR antagonism restricts the dissemination of A. baumannii in the pneumonia model. These results define a role for PAFR in A. baumannii interaction with host cells and suggest a mechanism for the entry of A. baumannii into the cytoplasm of host cells. PMID:22689572

  8. Deriving uncertainty factors for threshold chemical contaminants in drinking water.

    PubMed

    Ritter, Leonard; Totman, Céline; Krishnan, Kannan; Carrier, Richard; Vézina, Anne; Morisset, Véronique

    2007-10-01

    Uncertainty factors are used in the development of drinking-water guidelines to account for uncertainties in the database, including extrapolations of toxicity from animal studies and variability within humans, which result in some uncertainty about risk. The application of uncertainty factors is entrenched in toxicological risk assessment worldwide, but is not applied consistently. This report, prepared in collaboration with Health Canada, provides an assessment of the derivation of the uncertainty factor assumptions used in developing drinking-water quality guidelines for chemical contaminants. Assumptions used by Health Canada in the development of guidelines were compared to several other major regulatory jurisdictions. This assessment has revealed that uncertainty factor assumptions have been substantially influenced by historical practice. While the application of specific uncertainty factors appears to be well entrenched in regulatory practice, a well-documented and disciplined basis for the selection of these factors was not apparent in any of the literature supporting the default assumptions of Canada, the United States, Australia, or the World Health Organization. While there is a basic scheme used in most cases in developing drinking-water quality guidelines for nonthreshold contaminants by the jurisdictions included in this report, additional factors are sometimes included to account for other areas of uncertainty. These factors may include extrapolating subchronic data to anticipated chronic exposure, or use of a LOAEL instead of a NOAEL. The default value attributed to each uncertainty factor is generally a factor of 3 or 10; however, again, no comprehensive guidance to develop and apply these additional uncertainty factors was evident from the literature reviewed. A decision tree has been developed to provide guidance for selection of appropriate uncertainty factors, to account for the range of uncertainty encountered in the risk assessment process

  9. Non‐Thermal Plasma in Contact with Water: The Origin of Species

    PubMed Central

    Gorbanev, Yury

    2016-01-01

    Abstract Non‐thermal atmospheric pressure plasma has attracted considerable attention in recent years due to its potential for biomedical applications. Determining the mechanism of the formation of reactive species in liquid treated with plasma is thus of paramount importance for both fundamental and applied research. In this work, the origin of reactive species in plasma‐treated aqueous solutions was investigated by using spin‐trapping, hydrogen and oxygen isotopic labelling and electron paramagnetic resonance (EPR) spectroscopy. The species originating from molecules in the liquid phase and those introduced with the feed gas were differentiated by EPR and 1H NMR analysis of liquid samples. The effects of water vapour and oxygen admixtures in the feed gas were investigated. All the reactive species detected in the liquid samples were shown to be formed largely in the plasma gas phase. It is suggested that hydrogen peroxide (determined by UV/Vis analysis) is formed primarily in the plasma tube, whereas the radical species ⋅OOH, ⋅OH and ⋅H are proposed to originate from the region between the plasma nozzle and the liquid sample. PMID:26833560

  10. Characterization factors for water footprint considering the scarcity of green and blue water sources

    NASA Astrophysics Data System (ADS)

    Oki, T.; Kondo, T.; Pokhrel, Y. N.; Hanasaki, N.

    2011-12-01

    The original concept of virtual water trade was invented to illustrate how much water demand can be reduced by importing food products (Allan 1996), and expanded for meat products and industrial products (Oki and Kanae, 2004). However, there was a confusion between "virtual trade of water" (original) and "trade of virtual water" (misinterpretation but widely accepted), and "virtual water" has been recognized as how much water was used to produce the commodity. Then, the concept has some analogy to carbon footprint (CFP) which is an indicator of total emission of greenhouse gases, and nowadays called water footprint (WFP, Hoekstra, 2004). However, WFP itself is just an inventory of water usages under the framework of life cycle assessment (LCA), and the volume of WFP does not necessary reflect the environmental impacts of water usages because consumptive water use of 100 liter from ground water in arid regions just before rainy season would have more environmental impacts than consumptive water use of 100 liter from rain water in humid regions during snow melt season. In the case of CFP, the emissions of five greenhouse gases except for CO2 were converted into CO2 equivalent volumes by considering the sensitivity for the global warming potential, and summed up into CFP. Here, we propose a new idea objectively determining the weights (characterization factors) for blue water usages, such as from river and ground water, to be converted into green water equivalent in each region and time. The weights are inversely proportional to the area required to obtain the same amount of green water, and water balance model can provide the basic information. The new concept was applied to the WFP of Japan through the imports of major crops. As an inventory, WFP was 15.5 km3/y of rain water, 2.2 km3/y of river water, and 2.0 km3/y of non-renewable and non-local water (NRNL water) for year 2000, however, considering the proposed characterization factors in each region (0.5 x 0

  11. Evaluation of Electrolytically-Generated Hypochlorous Acid ('Electrolyzed Water') for Sanitation of Meat and Meat-Contact Surfaces.

    PubMed

    Veasey, Shawnna; Muriana, Peter M

    2016-06-13

    'Electrolyzed water' generators are readily available in the food industry as a renewable source of hypochlorous acid that eliminates the need for workers to handle hazardous hypochlorite concentrates. We applied electrolyzed water (EW) directly to multi-strain cocktails of Listeria monocytogenes, E. coli O157:H7, and Salmonella sp. at 250 ppm free available chlorine (FAC) and achieved greater than 6-log reductions in 2 min. Lower EW values were examined as antimicrobial interventions for fresh meat (beef carcasses), processed meats (frankfurters), and food contact surfaces (slicing blades). Little or no reduction relative to controls was observed when generic E. coli-inoculated beef carcasses or L. monocytogenes-inoculated frankfurters were showered with EW. Spray application of EW (25 and 250-ppm FAC) onto L. monocytogenes-inoculated slicing blades showed that greater reductions were obtained with 'clean' (3.6 and 5.7-log reduction) vs. 'dirty' (0.6 and 3.3-log reduction) slicing blades, respectively. Trials with L. monocytogenes-inoculated protein-EW solutions demonstrated that protein content as low as 0.1% is capable of eliminating FAC, reducing antimicrobial activity against L. monocytogenes. EW appears better positioned as a surface sanitizer with minimal organic material that can otherwise act as an effective reducing agent to the oxidizing solution rendering it ineffective.

  12. Risk Factors for Carbapenemase-Producing Carbapenem-Resistant Enterobacteriaceae (CP-CRE) Acquisition Among Contacts of Newly Diagnosed CP-CRE Patients.

    PubMed

    Schwartz-Neiderman, Anat; Braun, Tali; Fallach, Noga; Schwartz, David; Carmeli, Yehuda; Schechner, Vered

    2016-10-01

    OBJECTIVE Carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) are extremely drug-resistant pathogens. Screening of contacts of newly identified CP-CRE patients is an important step to limit further transmission. We aimed to determine the risk factors for CP-CRE acquisition among patients exposed to a CP-CRE index patient. METHODS A matched case-control study was performed in a tertiary care hospital in Israel. The study population was comprised of patients who underwent rectal screening for CP-CRE following close contact with a newly identified CP-CRE index patient. Cases were defined as positive tests for CP-CRE. For each case patient, 2 matched controls were randomly selected from the pool of contacts who tested negative for CP-CRE following exposure to the same index case. Bivariate and multivariate analyses were conducted using conditional logistic regression. RESULTS In total, 53 positive contacts were identified in 40 unique investigations (896 tests performed on 735 contacts) between October 6, 2008, and June 7, 2012. bla KPC was the only carbapenemase identified. In multivariate analysis, risk factors for CP-CRE acquisition among contacts were (1) contact with an index patient for ≥3 days (odds ratio [OR], 9.8; 95% confidence interval [CI], 2.0-48.9), (2) mechanical ventilation (OR, 4.1; 95% CI, 1.4-11.9), and (3) carriage or infection with another multidrug-resistant organism (MDRO; OR, 2.6; 95% CI, 1.0-7.1). Among patients who received antibiotics, cephalosporins were associated with a lower risk of acquisition. CONCLUSIONS Patient characteristics (ventilation and carriage of another MDRO) as well as duration of contact are risk factors for CP-CRE acquisition among contacts. The role of cephalosporins requires further study. Infect Control Hosp Epidemiol 2016;1-7.

  13. Dynamic factor analysis for estimating ground water arsenic trends.

    PubMed

    Kuo, Yi-Ming; Chang, Fi-John

    2010-01-01

    Drinking ground water containing high arsenic (As) concentrations has been associated with blackfoot disease and the occurrence of cancer along the southwestern coast of Taiwan. As a result, 28 ground water observation wells were installed to monitor the ground water quality in this area. Dynamic factor analysis (DFA) is used to identify common trends that represent unexplained variability in ground water As concentrations of decommissioned wells and to investigate whether explanatory variables (total organic carbon [TOC], As, alkalinity, ground water elevation, and rainfall) affect the temporal variation in ground water As concentration. The results of the DFA show that rainfall dilutes As concentration in areas under aquacultural and agricultural use. Different combinations of geochemical variables (As, alkalinity, and TOC) of nearby monitoring wells affected the As concentrations of the most decommissioned wells. Model performance was acceptable for 11 wells (coefficient of efficiency >0.50), which represents 52% (11/21) of the decommissioned wells. Based on DFA results, we infer that surface water recharge may be effective for diluting the As concentration, especially in the areas that are relatively far from the coastline. We demonstrate that DFA can effectively identify the important factors and common effects representing unexplained variability common to decommissioned wells on As variation in ground water and extrapolate information from existing monitoring wells to the nearby decommissioned wells.

  14. Studies on kinetics of water quality factors to establish water transparency model in Neijiang River, China.

    PubMed

    Li, Ronghui; Pan, Wei; Guo, Jinchuan; Pang, Yong; Wu, Jianqiang; Li, Yiping; Pan, Baozhu; Ji, Yong; Ding, Ling

    2014-05-01

    The basis for submerged plant restoration in surface water is to research the complicated dynamic mechanism of water transparency. In this paper, through the impact factor analysis of water transparency, the suspended sediment, dissolved organic matter, algae were determined as three main impactfactors for water transparency of Neijiang River in Eastern China. And the multiple regression equation of water transparency and sediment concentration, permanganate index, chlorophyll-a concentration was developed. Considering the complicated transport and transformation of suspended sediment, dissolved organic matter and algae, numerical model of them were developed respectively for simulating the dynamic process. Water transparency numerical model was finally developed by coupling the sediment, water quality, and algae model. These results showed that suspended sediment was a key factor influencing water transparency of Neijiang River, the influence of water quality indicated by chemical oxygen demand and algal concentration indicated by chlorophyll a were indeterminate when their concentrations were lower, the influence was more obvious when high concentrations are available, such three factors showed direct influence on water transparency.

  15. Factors stimulating propagation of legionellae in cooling tower water

    SciTech Connect

    Yamamoto, Hiroyuki; Sugiura, Minoru; Kusunoki, Shinji; Ezaki, Takayuki; Ikedo, Masanari; Yabuuchi, Eiko )

    1992-04-01

    The authors survey of cooling tower water demonstrated that the highest density of legionellae, {ge}10{sup 4} CFU/100 ml, appeared in water containing protozoa, {ge}10{sup 2} MPN/100 ml, and heterotrophic bacteria, {ge}10{sup 6} CFU/100 ml, at water temperatures between 25 and 35C. Viable counts of legionellae were detected even in the winter samples, and propagation, up to 10{sup 5} CFU/100 ml, occurs in summer. The counts of legionellae correlated positively with increases in water temperature, pH, and protozoan counts, but not with heterotrophic bacterial counts. The water temperature of cooling towers may promote increases in the viable counts of legionellae, and certain microbes, e.g., protozoa or some heterotrophic bacteria, may be a factor stimulating the propagation of legionellae.

  16. Arsenic in Drinking Water in Bangladesh: Factors Affecting Child Health

    PubMed Central

    Aziz, Sonia N.; Aziz, Khwaja M. S.; Boyle, Kevin J.

    2014-01-01

    The focus of this paper is to present an empirical model of factors affecting child health by observing actions households take to avoid exposure to arsenic in drinking water. Millions of Bangladeshis face multiple health hazards from high levels of arsenic in drinking water. Safe water sources are either expensive or difficult to access, affecting people’s individuals’ time available for work and ultimately affecting the health of household members. Since children are particularly susceptible and live with parents who are primary decision makers for sustenance, parental actions linking child health outcomes is used in the empirical model. Empirical results suggest that child health is significantly affected by the age and gender of the household water procurer. Adults with a high degree of concern for children’s health risk from arsenic contamination, and who actively mitigate their arsenic contaminated water have a positive effect on child health. PMID:24982854

  17. Arsenic in drinking water in bangladesh: factors affecting child health.

    PubMed

    Aziz, Sonia N; Aziz, Khwaja M S; Boyle, Kevin J

    2014-01-01

    The focus of this paper is to present an empirical model of factors affecting child health by observing actions households take to avoid exposure to arsenic in drinking water. Millions of Bangladeshis face multiple health hazards from high levels of arsenic in drinking water. Safe water sources are either expensive or difficult to access, affecting people's individuals' time available for work and ultimately affecting the health of household members. Since children are particularly susceptible and live with parents who are primary decision makers for sustenance, parental actions linking child health outcomes is used in the empirical model. Empirical results suggest that child health is significantly affected by the age and gender of the household water procurer. Adults with a high degree of concern for children's health risk from arsenic contamination, and who actively mitigate their arsenic contaminated water have a positive effect on child health.

  18. High and low contact frequency cardiac rehabilitation programmes elicit similar improvements in cardiorespiratory fitness and cardiovascular risk factors.

    PubMed

    LaHaye, Stephen A; Lacombe, Shawn P; Koppikar, Sahil; Lun, Grace; Parsons, Trisha L; Hopkins-Rosseel, Diana

    2014-12-01

    Cardiac rehabilitation (CR) is a proven intervention that substantially improves physical health and decreases death and disability following a cardiovascular event. Traditional CR typically involves 36 on-site exercise sessions spanning a 12-week period. To date, the optimal dose of CR has yet to be determined. This study compared a high contact frequency CR programme (HCF, 34 on-site sessions) with a low contact frequency CR programme (LCF, eight on-site sessions) of equal duration (4 months). A total of 961 low-risk cardiac patients (RARE score <4) self-selected either a HCF (n = 469) or LCF (n = 492) CR programme. Cardiorespiratory fitness and cardiovascular risk factors were measured on admission and discharge. Similar proportions of patients completed HCF (n = 346) and LCF (n = 351) (p = 0.398). Patients who were less fit (<8 METs) were more likely to drop out of the LCF group, while younger patients (<60 years) were more likely to drop out of the HCF group. Both groups experienced similar reductions in weight (-2.3 vs. -2.4 kg; p = 0.779) and improvements in cardiorespiratory fitness (+1.5 vs. +1.4 METs; p = 0.418). Patients in the LCF programme achieved equivalent results to those in the HCF programme. Certain subgroups of patients, however, may benefit from participation in a HCF programme, including those patients who are predisposed to prematurely discontinuing the programme and those patients who would benefit from increased monitoring. The LCF model can be employed as an alternative option to widen access and participation for patients who are unable to attend HCF programmes due to distance or time limitations. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  19. Identification and Assessment of Potential Water Quality Impact Factors for Drinking-Water Reservoirs

    PubMed Central

    Gu, Qing; Deng, Jinsong; Wang, Ke; Lin, Yi; Li, Jun; Gan, Muye; Ma, Ligang; Hong, Yang

    2014-01-01

    Various reservoirs have been serving as the most important drinking water sources in Zhejiang Province, China, due to the uneven distribution of precipitation and severe river pollution. Unfortunately, rapid urbanization and industrialization have been continuously challenging the water quality of the drinking-water reservoirs. The identification and assessment of potential impacts is indispensable in water resource management and protection. This study investigates the drinking water reservoirs in Zhejiang Province to better understand the potential impact on water quality. Altogether seventy-three typical drinking reservoirs in Zhejiang Province encompassing various water storage levels were selected and evaluated. Using fifty-two reservoirs as training samples, the classification and regression tree (CART) method and sixteen comprehensive variables, including six sub-sets (land use, population, socio-economy, geographical features, inherent characteristics, and climate), were adopted to establish a decision-making model for identifying and assessing their potential impacts on drinking-water quality. The water quality class of the remaining twenty-one reservoirs was then predicted and tested based on the decision-making model, resulting in a water quality class attribution accuracy of 81.0%. Based on the decision rules and quantitative importance of the independent variables, industrial emissions was identified as the most important factor influencing the water quality of reservoirs; land use and human habitation also had a substantial impact on water quality. The results of this study provide insights into the factors impacting the water quality of reservoirs as well as basic information for protecting reservoir water resources. PMID:24919129

  20. Effect of the hot water extract of Artocarpus camansi leaves on 2,4,6-trinitrochlorobenzene (TNCB)-induced contact hypersensitivity in mice.

    PubMed

    Salonga, Reginald Bayani; Hisaka, Shinsuke; Nose, Mitsuhiko

    2014-01-01

    Medicinal plants with reported anti-inflammatory activity could have the potential use as anti-allergens and inhibitors of allergic contact dermatitis reactions produced by allergens and chemicals. Some species from the genus Artocarpus were reported to have anti-inflammatory activity. In the Philippines one local source is Artocarpus camansi BLANCO (Moraceae), which is utilized as an ingredient of their cuisine, and decoction of leaves is used for diabetes and baths of people with rheumatism. The objective of this study was to evaluate the effect of the hot water extract of A. camansi leaves on contact hypersensitivity (CHS) in mice. Contact hypersensitivity was induced using 2,4,6-trinitrochlorobenzene (TNCB). The results showed that the A. camansi hot water extract exhibited significant activity against the swelling produced during 24 h and 48 h post-challenge. The same responses were observed from the mice that received the kamansi ethanol-precipitate (KEP) and kamansi ethanol precipitate water-soluble (KEPWS) fractions. Since the high molecular mass fraction showed the significant activity, we therefore speculate that the compound responsible might be a polysaccharide and/or glycoprotein. In conclusion, our results suggest that the hot water extract of A. camansi leaves might be an effective natural product to treat allergic contact dermatitis. However, further investigations are required to understand the mechanisms involved.

  1. Biosurfactant as an Enhancer of Geologic Carbon Storage: Microbial Modification of Interfacial Tension and Contact Angle in Carbon dioxide/Water/Quartz Systems

    PubMed Central

    Park, Taehyung; Joo, Hyun-Woo; Kim, Gyeong-Yeong; Kim, Seunghee; Yoon, Sukhwan; Kwon, Tae-Hyuk

    2017-01-01

    Injecting and storing of carbon dioxide (CO2) in deep geologic formations is considered as one of the promising approaches for geologic carbon storage. Microbial wettability alteration of injected CO2 is expected to occur naturally by microorganisms indigenous to the geologic formation or microorganisms intentionally introduced to increase CO2 storage capacity in the target reservoirs. The question as to the extent of microbial CO2 wettability alteration under reservoir conditions still warrants further investigation. This study investigated the effect of a lipopeptide biosurfactant—surfactin, on interfacial tension (IFT) reduction and contact angle alteration in CO2/water/quartz systems under a laboratory setup simulating in situ reservoir conditions. The temporal shifts in the IFT and the contact angle among CO2, brine, and quartz were monitored for different CO2 phases (3 MPa, 30°C for gaseous CO2; 10 MPa, 28°C for liquid CO2; 10 MPa, 37°C for supercritical CO2) upon cultivation of Bacillus subtilis strain ATCC6633 with induced surfactin secretion activity. Due to the secreted surfactin, the IFT between CO2 and brine decreased: from 49.5 to 30 mN/m, by ∼39% for gaseous CO2; from 28.5 to 13 mN/m, by 54% for liquid CO2; and from 32.5 to 18.5 mN/m, by ∼43% for supercritical CO2, respectively. The contact angle of a CO2 droplet on a quartz disk in brine increased: from 20.5° to 23.2°, by 1.16 times for gaseous CO2; from 18.4° to 61.8°, by 3.36 times for liquid CO2; and from 35.5° to 47.7°, by 1.34 times for supercritical CO2, respectively. With the microbially altered CO2 wettability, improvement in sweep efficiency of injected and displaced CO2 was evaluated using 2-D pore network model simulations; again the increment in sweep efficiency was the greatest in liquid CO2 phase due to the largest reduction in capillary factor. This result provides novel insights as to the role of naturally occurring biosurfactants in CO2 storage and suggests that

  2. Developing Region-Specific Water Energy Intensity Factors for the U.S. Water System

    NASA Astrophysics Data System (ADS)

    Newmark, R. L.; Kandt, A.; Macknick, J.; Daw, J.; Hunsberger, R.; Tomberlin, G.

    2014-12-01

    Energy use by water and wastewater treatment plants equates to approximately 4% of total energy use in the United States. For many municipal water and wastewater treatment plants, energy costs related to pumping, treating, and transporting water represent a large fraction of total costs. The energy intensity of any given utility is heavily variant dependent on location and regional conditions, but energy requirements are generally expected to increase in many regions due to limits on water resources and regulatory requirements for water quality. Quantifying the energy use associated with our nation's water system - the energy needed to convey, extract, treat and distribute water in a particular location - is an important step in understanding the impact and interconnections of the water system on the energy system, in identifying opportunities for savings, and in improving existing modeling and analytic methods for both energy and water systems. Local topography and other regional conditions can greatly affect how much energy a particular water facility utilizes, which in turn affects its relationship with the broader electricity sector. This research evaluates what previous and current efforts have been undertaken to quantify water energy intensity factors (w-EIFs) on a regional scale, provides first steps for cataloguing resulting datasets and findings, and initiates a methodology for developing regional and localized w-EIFs. Improved regional w-EIFs can facilitate national reductions in energy intensity metrics by highlighting areas where energy savings opportunities could provide the greatest benefit.

  3. Equivalences between refractive index and equilibrium water content of conventional and silicone hydrogel soft contact lenses from automated and manual refractometry.

    PubMed

    González-Méijome, José M; López-Alemany, Antonio; Lira, Madalena; Almeida, José B; Oliveira, M Elisabete C D Real; Parafita, Manuel A

    2007-01-01

    The purpose of the present study was to develop mathematical relationships that allow obtaining equilibrium water content and refractive index of conventional and silicone hydrogel soft contact lenses from refractive index measures obtained with automated refractometry or equilibrium water content measures derived from manual refractometry, respectively. Twelve HEMA-based hydrogels of different hydration and four siloxane-based polymers were assayed. A manual refractometer and a digital refractometer were used. Polynomial models obtained from the sucrose curves of equilibrium water content against refractive index and vice-versa were used either considering the whole range of sucrose concentrations (16-100% equilibrium water content) or a range confined to the equilibrium water content of current soft contact lenses (approximately 20-80% equilibrium water content). Values of equilibrium water content measured with the Atago N-2E and those derived from the refractive index measurement with CLR 12-70 by the applications of sucrose-based models displayed a strong linear correlation (r2 = 0.978). The same correlations were obtained when the models are applied to obtain refractive index values from the Atago N-2E and compared with those (values) given by the CLR 12-70 (r2 = 0.978). No significantly different results are obtained between models derived from the whole range of the sucrose solution or the model limited to the normal range of soft contact lens hydration. Present results will have implications for future experimental and clinical research regarding normal hydration and dehydration experiments with hydrogel polymers, and particularly in the field of contact lenses. 2006 Wiley Periodicals, Inc.

  4. NK cells control HIV-1 infection of macrophages through soluble factors and cellular contacts in the human decidua.

    PubMed

    Quillay, H; El Costa, H; Duriez, M; Marlin, R; Cannou, C; Madec, Y; de Truchis, C; Rahmati, M; Barré-Sinoussi, F; Nugeyre, M T; Menu, E

    2016-06-06

    During the first trimester of pregnancy, HIV-1 in utero transmission is rare despite the permissivity of the placenta and the decidua (the uterine mucosa during pregnancy) to infection. In the decidua from the first trimester of pregnancy, macrophages (dMs) are the HIV-1 main target cells. Decidual natural killer (dNK) cells account for 70 % of decidual leukocytes. They display distinct phenotype and functions compared to peripheral NK cells. At the periphery, NK cells are involved in the control of HIV-1 infection. In this study, we investigate whether human decidual natural killer (dNK) cells control dM HIV-1 infection. Autologous cocultures of infected dMs with dNK cells reveal that dNK cells strongly inhibit dM HIV-1 infection. The addition of dNK cells to dMs at different times after infection suggests that the control occurs before the complete establishment of the infection. Double chamber cocultures show that cellular contacts are necessary for an optimal control of infection. Nevertheless, soluble factors secreted by dMs and dNK cells in double chamber cocultures partially inhibit dM HIV-1 infection, indicating that soluble factors have also a role in the control of infection. IFN-γ secretion is increased in infected and uninfected cocultures. We show that IFN-γ is involved in the control of dM HIV-1 infection by dNK cells. These results demonstrate that human dNK cells inhibit efficiently HIV-1 infection in dMs in vitro, and highlight the role of innate immune determinants in the control of HIV-1 transmission.

  5. Environmental Impact of the Contact and Sonoma Mercury Mines on Water, Sediment, and Biota in Anna Belcher and Little Sulphur Creek Watersheds, Sonoma County, California

    USGS Publications Warehouse

    Rytuba, James J.; Hothem, Roger L.; May, Jason T.; Kim, Christopher S.; Lawler, David; Goldstein, Daniel

    2009-01-01

    The Contact and Sonoma mercury (Hg) deposits are among the youngest Hg deposits in the Coast Range Hg mineral belt and are located in the western part of the Clear Lake volcanic field in Sonoma County, California. The mine workings and tailings are located in the headwaters of Anna Belcher Creek, which is a tributary to Little Sulphur Creek. The Contact Hg mine produced about 1,000 flasks of Hg, and the Sonoma mine produced considerably less. Waste rock and tailings eroded from the Contact and Sonoma mines have contributed Hg-enriched mine waste material to the headwaters of Anna Belcher Creek. The mines are located on federal land managed by the U.S. Bureau of Land Management (USBLM). The USBLM requested that the U.S. Geological Survey (USGS) measure and characterize Hg and other geochemical constituents in tailings, sediment, water, and biota at the Contact and Sonoma mines and in Anna Belcher and Little Sulphur Creeks. This report is made in response to the USBLM request, the lead agency mandated to conduct a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) - Removal Site Investigation (RSI). The RSI applies to removal of Hg-contaminated mine waste from the Contact and Sonoma mines as a means of reducing Hg transport to Anna Belcher and Little Sulphur Creeks. This report summarizes data obtained from field sampling of mine tailings, waste rock, sediment, and water at the Contact and Sonoma mines that was initiated on April 20 during a storm event, and on June 19, 2001. Further sampling of water, sediment, and biota in a pond and tributaries that drain from the mine area was completed on April 1, 2003. Our results permit a preliminary assessment of the mining sources of Hg and associated chemical constituents that could elevate levels of monomethyl Hg (MMeHg) in tributaries and biota that are impacted by historic mining.

  6. Pesticides in ground water: distribution, trends, and governing factors

    USGS Publications Warehouse

    Barbash, Jack; Resek, Elizabeth A.

    1997-01-01

    A comprehensive review of published information on the distribution and behavior of pesticides and their transformation products in ground water indicates that pesticides from every chemical class have been detected in ground waters of the United States. Many of these compounds are commonly present at low concentrations in ground water beneath agricultural land. Little information is available on their occurrence beneath non-agricultural land, although the intensity of their use in such areas (on lawns, golf courses, rights of way, timberlands, etc.) is often comparable to, or greater than agricultural use. Information on pesticides in ground water is not sufficient to provide either a statistically representative view of pesticide occurrence in ground water across the United States, or an indication of long-term trends or changes in the severity or extent of this contamination over the past three decades. This is largely due to wide variations in analytical detection limits, well selection procedures, and other design features among studies conducted in different areas or at different times. Past approaches have not been well suited for distinguishing "point source" from "nonpoint source" pesticide contamination. Among the variety of natural and anthropogenic factors examined, those that appear to be most strongly associated with the intensity of pesticide contamination of ground water are the depth, construction and age of the sampled wells, the amount of recharge (by precipitation or irrigation), and the depth of tillage. Approaches commonly employed for predicting pesticide distributions in the subsurface--including computer simulations, indicator solutes (e.g., nitrate or tritium), and ground-water vulnerability assessments--generally provide unreliable predictions of pesticide occurrence in ground water. Such difficulties may arise largely from a general failure to account for the preferential transport of pesticides in the subsurface. Significant

  7. Decrease in water activity due to fluid absent partial melting monitored with water content in biotite in the Western Adamello contact aureole (Italy)

    NASA Astrophysics Data System (ADS)

    Siron, Guillaume; Baumgartner, Lukas; Bouvier, Anne-Sophie; Vennemann, Torsten

    2016-04-01

    The fluorine and chlorine exchange on the hydroxyl site in micas is used to monitor changes in fluid composition (Munoz 1984). Most studies assume that the OH-site does not contain vaccancies, since the vast majority of studies use analytical techniques that does not allow to directly measure the OH- content of the mica. Nevertheless, studies have shown that significant amounts of O2- are present, and its concentration increases with temperature and titanium content. This feature was intrepreted as the consequence of a Ti-oxygen exchange in amphibolite and granulite facies rocks (Dyar et al. 1993, Cesare et al. 2008). Here, we present OH, F, Cl data for biotite from contact aureoles from biotite-schist to partially molten sillimanite-cordierite schists. OH-F-Cl content of biotites were analyzed using Secondary Ion Mass Spectrometry (SIMS), and major elements were analyzed by EMP. Samples were collected in the mid-crustal Western Adamello contact aureole (Italian Alps, Floess and Baumgartner, 2013). For that purpose we used biotite standards with water content constrained by Thermal Conversion Elemental Analyzer (TC/EA) see Bauer and Vennemann 2014, at a level of precision of 0.1-0.2 wt% (2SD). SIMS measurements typically have a precision of 0.1wt% (2SD), corresponding to the homogeneity of the internal standard at the SwissSIMS laboratory. OH- content decreases in samples with increasing peak temperature and Ti content (Ti range for biotites of 0.15-0.42 p.f.u for all samples). Nevertheless, within each individual sample, OH- is not a function of Ti. Ti variations are about 0.4 p.f.u., which is ten times the analytical uncertainty of the EMP analysis (0.004 p.f.u., 1SD). Water content is constant within analytical precision for each sample. The mean of OH- measurements is 3.41 p.f.u. in biotite and garnet grade samples, whereas those of samples in the partially molten zone have values of 3.27 p.f.u. We do not see any correlation with XMg or F and Cl. Hence, we

  8. The prevalence and influencing factors of methicillin-resistant Staphylococcus aureus carriage in people in contact with livestock: A systematic review.

    PubMed

    Liu, Weidong; Liu, Zhichang; Yao, Zhenjiang; Fan, Yanping; Ye, Xiaohua; Chen, Sidong

    2015-05-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is becoming a serious epidemic worldwide. Recently, studies have shown that people in contact with livestock may have a greater chance of MRSA carriage. We aimed to establish the prevalence of MRSA among people in contact with livestock and review the factors influencing MRSA carriage. We systematically examined published epidemiologic studies on MRSA prevalence in people in contact with livestock using Pubmed, Medline, Embase, Ovid, and the Cochrane Library. Prevalence estimates were pooled using a random-effects model. Study heterogeneity was assessed using Q statistics and quantified with I(2) statistics. Thirty-three eligible studies were included in this systematic review. Prevalence of MRSA ranged from 0.0%-85.8%. The pooled prevalence estimate of MRSA was 14.2% (95% confidence interval, 9.1%-20.1%) for people in contact with livestock. Substantial heterogeneity in eligible studies was noted (χ(2) = 1,025; P < .001; I(2) = 96.9%). Subgroup analysis showed the prevalence of MRSA was high in people from Europe (15.9%), farmers (18.2%), and by longitudinal study design (38.9%). Animal contact and intensity of animal contact were associated with increased risk of MRSA carriage. Our findings suggest that there may be transmission of MRSA between animals and humans. Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  9. Impact of Environmental Factors on Legionella Populations in Drinking Water

    PubMed Central

    Schwake, David Otto; Alum, Absar; Abbaszadegan, Morteza

    2015-01-01

    To examine the impact of environmental factors on Legionella in drinking water distribution systems, the growth and survival of Legionella under various conditions was studied. When incubated in tap water at 4 °C, 25 °C, and 32 °C, L. pneumophila survival trends varied amongst the temperatures, with the stable populations maintained for months at 25 °C and 32 °C demonstrating that survival is possible at these temperatures for extended periods in oligotrophic conditions. After inoculating coupons of PVC, copper, brass, and cast iron, L. pneumophila colonized biofilms formed on each within days to a similar extent, with the exception of cast iron, which contained 1-log less Legionella after 90 days. L. pneumophila spiked in a model drinking water distribution system colonized the system within days. Chlorination of the system had a greater effect on biofilm-associated Legionella concentrations, with populations returning to pre-chlorination levels within six weeks. Biofilms sampled from drinking water meters collected from two areas within central Arizona were analyzed via PCR for the presence of Legionella. Occurrence in only one area indicates that environmental differences in water distribution systems may have an impact on the survival of Legionella. These results document the impact of different environmental conditions on the survival of Legionella in water. PMID:25996405

  10. Anomalous base and precious metals at oil-water contact in 1 Teague Well, Smackover Formation, southwest Arkansas

    SciTech Connect

    Price, P.E.; Lamore, F.E.; Kyle, J.R.; Kurtz, J.P.

    1988-02-01

    A core sample containing visible sulfide concentrations in an ooid grainstone unit of the Smackover Formation was collected from 8373 ft in the 1 Teague well, outpost McKamie field, Lafayette County, Arkansas. The sulfides are concentrated beneath a well-developed, high-amplitude stylolite that appears to have acted as a permeability barrier limiting sulfide development in the upper carbonate. Examination of the electric and descriptive log information for the interval revealed that: (1) the top of the sulfide zone corresponds to the existing oil-water contact, (2) scattered sulfides occur over an 84-ft interval beginning at 8373 ft, (3) an interval of greater than 10% porosity roughly coincides with the sulfide interval, and (4) an interval of hydrogen sulfide begins about 30 ft below the top of the sulfide interval and extends well below the last described sulfides. Assay results from a 1-ft composite sample showed that the core contains 36% zinc, 12% lead, and 888 ppm silver. The silver value equals about 26 oz/ton which is a high-grade ore in a mineable setting. The Zn/(Zn + Pb) ratio of 0.75 is typical of Gulf Coast salt dome hosted mineralization with ratios of 0.68 to 0.90. The Fe/(Fe + Zn) ratio on the other hand is 0.02 which is far below the 0.87 to 0.97 range of salt dome hosted sulfides. Petrographic examination indicates complex replacement and pore-filling mineralization. Minerals forming the late-stage mineralization assemblage include fine-grained replacement sphalerite-galena-acanthite-chalcopyrite-pyrite/marcasite-dolomite-coarse-grained sphalerite-calcite.

  11. Transforming growth factor-β/Smad3 signalling regulates inflammatory responses in a murine model of contact hypersensitivity

    PubMed Central

    Anthoni, M; Fyhrquist-Vanni, N; Wolff, H; Alenius, H; Lauerma, A

    2008-01-01

    Background Transforming growth factor (TGF)-β is an important modulator of immune functions and cellular responses, such as differentiation, proliferation, migration and apoptosis. The Smad proteins, which are intracellular TGF-β signal transducers, mediate most actions of TGF-β. Objectives This study examines the role of Smad3 in a murine model of contact hypersensitivity (CHS). Methods The CHS response to oxazolone was studied in Smad3-deficient mice. The ear swelling response was measured and skin biopsies from oxazolone-sensitized skin areas were obtained for RNA isolation, immunohistochemical analyses and histology. Ear draining lymph nodes were collected for RNA isolation and proliferation tests. Quantitative real-time polymerase chain reaction was used to quantify mRNA expression of cytokines, chemokines and transcription factors. Results The expression of proinflammatory [interleukin (IL)-1β, tumour necrosis factor-α, IL-6], Th2 (IL-4) and Th17 type cytokines (IL-17), as well as regulatory components (TGF-β, Foxp3) increased significantly at the mRNA level in the skin of oxazolone-treated Smad3−/− mice when compared with wild-type controls. The expression of the Th1 type cytokine IFN-γ and the chemokines CXCL9 and CXCL10 was, however, unaffected by the lack of Smad3. The number of neutrophils and expression of the chemokines CCL3 and CXCL5, which are both involved in neutrophil recruitment, were increased in mice lacking Smad3. Also Th2 type chemokines CCL24, CCL3 and CXCL5 were increased in the skin of Smad3−/− mice compared with wild-type mice. In the lymph nodes, mRNA of IL-1β and IL-17, but not IL-4, TGF-β or Foxp3, was increased in Smad3−/− mice during the CHS response. Conclusions The lack of intact TGF-β signalling via Smad3 results in an increased proinflammatory, Th2 and Th17 type response in the skin, as well as increased expression of regulatory elements such as TGF-β and Foxp3. Understanding the role of Smad3 in the CHS

  12. Factors governing water condensation in the Martian atmosphere

    NASA Technical Reports Server (NTRS)

    Colburn, David S.; Pollack, J. B.; Haberle, Robert M.

    1988-01-01

    Modeling results are presented suggesting a diurnal condensation cycle at high altitudes at some seasons and latitudes. In a previous paper, the use of atmospheric optical depth measurements at the Viking lander site to show diurnal variability of water condensation at different seasons of the Mars year was described. Factors influencing the amount of condensation include latitude, season, atmospheric dust content and water vapor content at the observation site. A one-dimensional radiative-convective model is used herein based on the diabatic heating routines under development for the Mars General Circulation Model. The model predicts atmospheric temperature profiles at any latitude, season, time of day and dust load. From these profiles and an estimate of the water vapor, one can estimate the maximum occurring at an early morning hour (AM) and the minimum in the late afternoon (PM). Measured variations in the atmospheric optical density between AM and PM measurements were interpreted as differences in AM and PM condensation.

  13. [Factors affecting formation of THMs during dissolved organic nitrogen acetamide chlorination in drinking water].

    PubMed

    Chu, Wen-Hai; Gao, Nai-Yun; Zhao, Shi-Jia; Li, Qing-Song

    2009-05-15

    Chlorination disinfection greatly reduced bacteria and virus in drinking water. However, there is an unintended consequence of disinfection, the generation of chemical disinfection by-products (DBPs). Dissolved organic nitrogen (DON) as the important precursor of DBPs is of current concern. As acetamide (AcAm) occur in important bimolecular, we studied formation pathways for THMs during chlorination of model AcAm. The experiments are designed by Plackett-Burman and Box-Behnken methods. Factors affecting formation of THMs such as AcAm initial concentration, chlorine dosage, pH, temperature, Br(-) concentration and contact time were investigated. The results indicate that AcAm initial concentration, pH and temperature have little effects on formation of THMs. On the contrary, three other factors have important effects on formation of THMs, especially Br(-) concentration. The capacity of THMs generation varies very little when Br(-) has a constant concentration. Generation amount of THMs attach maximum under the condition that dosage of active chlorine, Br(-) concentration and contact time is 8.77 mg/L, 0.77 mg/L and 6.20 h respectively. Bromine ion plays a catalysis role on THMs formation. Controlling the concentration of bromine ion can reduce total generation amount of THMs via AcAm. Bromine partition coefficient tends to increasing along with contact time lapse. Controlling chlorination reaction time can lower the cancer risk. At last, the pathway is proposed for THMs formation via AcAm, and the catalysis mechanism of Br(-) was addressed.

  14. [Factors of stress in a local population of water vole].

    PubMed

    Zav'ialov, E L; Gerlinskaia, L A; Moshkin, M P

    2012-01-01

    Physiological mechanisms of stress have a multiple influence on the implementation of the adaptive capacity of individuals. From this perspective, analysis of factors determining the stress level of animals in changing environment acquires important ecological and evolutionary significance. In the paper the results are presented of long-term studies carried out at a site of irrigative channel being populated by water voles every year. The results show that high stress level of males is observed in connection with shortages of environmentally significant resources--food and sexual partners. An activation of adrenocortical function due to resources deficit is formed as a result of exacerbation of intraspecific competition that occurs at both low food supply and reducion in proportion of females in the local population. The effects of these factors are mediated through changes in spatio-ethological structure of the studied populations which are manifested in increased overlapping of individual home ranges. Food supply and lack of females have different effects on the level of glucocorticoids in resident and nonresident males. These results indicate that social interactions in water vole is the real stress factor even when total population is significantly depleted, which in North Baraba occurs when territory watering is reduced and suitable summer habitats are not plenty enough.

  15. Energy Factor Analysis for Gas Heat Pump Water Heaters

    SciTech Connect

    Gluesenkamp, Kyle R

    2016-01-01

    Gas heat pump water heaters (HPWHs) can improve water heating efficiency with zero GWP and zero ODP working fluids. The energy factor (EF) of a gas HPWH is sensitive to several factors. In this work, expressions are derived for EF of gas HPWHs, as a function of heat pump cycle COP, tank heat losses, burner efficiency, electrical draw, and effectiveness of supplemental heat exchangers. The expressions are used to investigate the sensitivity of EF to each parameter. EF is evaluated on a site energy basis (as used by the US DOE for rating water heater EF), and a primary energy-basis energy factor (PEF) is also defined and included. Typical ranges of values for the six parameters are given. For gas HPWHs, using typical ranges for component performance, EF will be 59 80% of the heat pump cycle thermal COP (for example, a COP of 1.60 may result in an EF of 0.94 1.28). Most of the reduction in COP is due to burner efficiency and tank heat losses. Gas-fired HPWHs are theoretically be capable of an EF of up to 1.7 (PEF of 1.6); while an EF of 1.1 1.3 (PEF of 1.0 1.1) is expected from an early market entry.

  16. Barrier function and natural moisturizing factor levels after cumulative exposure to a fruit-derived organic acid and a detergent: different outcomes in atopic and healthy skin and relevance for occupational contact dermatitis in the food industry.

    PubMed

    Angelova-Fischer, Irena; Hoek, Anne-Karin; Dapic, Irena; Jakasa, Ivone; Kezic, Sanja; Fischer, Tobias W; Zillikens, Detlef

    2015-12-01

    Fruit-derived organic compounds and detergents are relevant exposure factors for occupational contact dermatitis in the food industry. Although individuals with atopic dermatitis (AD) are at risk for development of occupational contact dermatitis, there have been no controlled studies on the effects of repeated exposure to multiple irritants, relevant for the food industry, in atopic skin. The aim of the study was to investigate the outcomes of repeated exposure to a fruit-derived organic acid and a detergent in AD compared to healthy volunteers. The volunteers were exposed to 2.0% acetic acid (AcA) and/or 0.5% sodium lauryl sulfate (SLS) in controlled tandem repeated irritation test. The outcomes were assessed by measurements of erythema, transepidermal water loss (TEWL) and natural moisturizing factor (NMF) levels. In the AD volunteers, repeated AcA exposure led to barrier disruption and significant TEWL increase; no significant differences after the same exposure in the healthy controls were found. Repeated exposure to SLS and the irritant tandems enhanced the reactions and resulted in a significantly higher increase in TEWL in the AD compared to the control group. Cumulative irritant exposure reduced the NMF levels in both groups. Differences in the severity of irritant-induced barrier impairment in atopic individuals contribute to the risk for occupational contact dermatitis in result of multiple exposures to food-derived irritants and detergents. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Topography of the Deuteronilus contact on Mars: Evidence for an ancient water/mud ocean and long-wavelength topographic readjustments

    NASA Astrophysics Data System (ADS)

    Ivanov, M. A.; Erkeling, G.; Hiesinger, H.; Bernhardt, H.; Reiss, D.

    2017-09-01

    VBF emplacement. The surface of the VBF-like Isidis Planitia unit is distinctly younger, ∼3.50 ± 0.01 Ga, which suggests that this unit formed independently. Neither volcanic nor glacial modes of emplacement are consistent with the topographic configuration and the shape of the Deuteronilus contact within both the northern plains and in Isidis Planitia. The broad flooding and formation of extensive water/mud reservoirs remains to be the most plausible mode of formation of the VBF in the northern plains and the VBF-like unit on the floor of the Isidis basin.

  18. Wettability determination by contact angle measurements: hvbB coal-water system with injection of synthetic flue gas and CO2.

    PubMed

    Shojai Kaveh, Narjes; Rudolph, E Susanne J; Wolf, Karl-Heinz A A; Ashrafizadeh, Seyed Nezameddin

    2011-12-01

    Geological sequestration of pure carbon dioxide (CO(2)) in coal is one of the methods to sequester CO(2). In addition, injection of CO(2) or flue gas into coal enhances coal bed methane production (ECBM). The success of this combined process depends strongly on the wetting behavior of the coal, which is function of coal rank, ash content, heterogeneity of the coal surface, pressure, temperature and composition of the gas. The wetting behavior can be evaluated from the contact angle of a gas bubble, CO(2) or flue gas, on a coal surface. In this study, contact angles of a synthetic flue gas, i.e. a 80/20 (mol%) N(2)/CO(2) mixture, and pure CO(2) on a Warndt Luisenthal (WL) coal have been determined using a modified pendant drop cell in a pressure range from atmospheric to 16 MPa and a constant temperature of 318 K. It was found that the contact angles of flue gas on WL coal were generally smaller than those of CO(2). The contact angle of CO(2) changes from water-wet to gas-wet by increasing pressure above 8.5 MPa while the one for the flue gas changes from water-wet to intermediate-wet by increasing pressure above 10 MPa.

  19. Analysis of River Water Quality and its influencing factors for the Effective Management of Water Environment

    NASA Astrophysics Data System (ADS)

    Shrestha, G.; Sadohara, S.; Yoshida, S.; Yuichi, S.

    2011-12-01

    In Japan, remarkable improvements in water quality have been observed over recent years because of regulations imposed on industrial wastewater and development of sewerage system. However, pollution loads from agricultural lands are still high and coverage ratio of sewerage system is still low in small and medium cities. In present context, nonpoint source pollution such as runoff from unsewered developments, urban and agricultural runoffs could be main water quality impacting factors. Further, atmospheric nitrogen (N) is the complex nonpoint source than can seriously affect river water environment. This study was undertaken to spatially investigate the present status of river water quality of Hadano Basin located in Kanagawa Prefecture, Japan. Water quality of six rivers was investigated and its relationship with nonpoint pollution sources was analyzed. This study, with inclusion of ground water circulation and atmospheric N, can be effectively employed for water quality management of other watersheds also, both with and without influence of ground water circulation. Hence, as a research area of this study, it is significant in terms of water quality management. Total nitrogen (TN) was found consistently higher in urbanized basins indicating that atmospheric N might be influencing TN of river water. Ground water circulation influenced both water quality and quantity. In downstream basins of Muro and Kuzuha rivers, Chemical oxygen demand (COD) and total phosphorus (TP) were diluted by ground water inflow. In Mizunashi River and the upstream of Kuzuha River, surface water infiltrated to the subsurface due to higher river bed permeability. Influencing factors considered in the analysis were unsewered population, agricultural land, urban area, forest and atmospheric N. COD and TP showed good correlation with unsewered population and agricultural land. While TN had good correlation with atmospheric N deposition. Multiple regression analysis between water quality

  20. Livestock drinking water microbiology and the factors influencing the quality of drinking water offered to cattle.

    PubMed

    LeJeune, J T; Besser, T E; Merrill, N L; Rice, D H; Hancock, D D

    2001-08-01

    The microbial quality of livestock drinking water was evaluated in 473 cattle water troughs located at 99 different cattle operations. The mean log10-transformed coliform and Escherichia coli concentrations per milliliter of trough water were 1.76 +/- 1.25 (SD) and 0.98 +/- 1.06 (SD), respectively. The degree of E. coli contamination was positively associated with the proximity of the water trough to the feedbunk, protection of the trough from direct sunlight, lower concentrations of protozoa in the water, and warmer weather. Salmonella sp. were isolated from 2/235 (0.8%) troughs and shigatoxigenic-E. coli O157 was recovered from 6/473 (1.3%) troughs. Four experimental microcosms simulating cattle water troughs were used to further evaluate the effects of protozoal populations on the survival of E. coli O157 in cattle water troughs. Escherichia coli O157 of bovine fecal origin proliferated in all microcosms. Reduction of protozoal populations by treatment with cycloheximide was associated with increased persistence of E. coli O157 concentrations in the microcosms. Water troughs are a major source of exposure of cattle to enteric bacteria, including a number of foodborne pathogens, and this degree of bacterial contamination appeared to be associated with potentially controllable factors.

  1. Orientation and structure-building role of the water molecules bound at the contact surface of the dihydrofolate reductase-methotrexate complex

    NASA Astrophysics Data System (ADS)

    Nagy, P.

    1988-04-01

    Orientation of ten water molecules bound strongly at the contact surface of the dihydrofolate reductase-methotrexate enzyme-inhibitor complex was determined theoretically. To optimize the orientation of the water molecules, a recent method based on a simple electrostatic model was applied. The electrostatic complementarity in the binary complex was investigated using the lock-and-key model, considering the effect of the water molecules as well. The strongly bound water molecules improve the electrostatic fit in the pteridine region of methotrexate. Their role in the benzoic amide and γ-glutamate region is to decrease the internal energy by creating water bridges among remote polar sites making it possible to form H-bonds. Some modifications in the inhibitor structure were proposed for achieving greater inhibitor potency. The presumably enhanced effect is ascribed to the free energy gain in repelling the water molecules from the contact surface to the bulk of the solvent, and, in other cases, to internal energy decreases due to better electrostatic fit in the enzyme-inhibitor complex.

  2. A Review of Operational Water Consumption and Withdrawal Factors for Electricity Generating Technologies

    SciTech Connect

    Macknick, Jordan; Newmark, Robin; Heath, Garvin; Hallett, K. C.

    2011-03-01

    This report provides estimates of operational water withdrawal and water consumption factors for electricity generating technologies in the United States. Estimates of water factors were collected from published primary literature and were not modified except for unit conversions. The presented water factors may be useful in modeling and policy analyses where reliable power plant level data are not available.

  3. Changes in composition and pore space of sand rocks in the oil water contact zone (section YU1 3-4, Klyuchevskaya area, Tomsk region)

    NASA Astrophysics Data System (ADS)

    Nedolivko, N.; Perevertailo, T.; Pavlovec, T.

    2016-09-01

    The article provides an analysis of specific features in changes of rocks in the oil water contact zone. The object of study is the formation YU1 3-4 (J3o1) of Klyuchevskaya oil deposit (West Siberian oil-gas province, Tomsk region). The research data allow the authors to determine vertical zoning of the surface structure and identify the following zones: oil saturation (weak alteration), bitumen-content dissolution, non-bitumen-content dissolution, cementation, including rocks not affected by hydrocarbon deposit. The rocks under investigation are characterized by different changes in composition, pore space, as well as reservoir filtration and volumetric parameters. Detection of irregularity in distribution of void- pore space in oil-water contact zones is of great practical importance. It helps to avoid the errors in differential pressure drawdown and explain the origin of low-resistivity collectors.

  4. Analytical application of solid contact ion-selective electrodes for determination of copper and nitrate in various food products and drinking water.

    PubMed

    Wardak, Cecylia; Grabarczyk, Malgorzata

    2016-08-02

    A simple, fast and cheap method for monitoring copper and nitrate in drinking water and food products using newly developed solid contact ion-selective electrodes is proposed. Determination of copper and nitrate was performed by application of multiple standard additions technique. The reliability of the obtained results was assessed by comparing them using the anodic stripping voltammetry or spectrophotometry for the same samples. In each case, satisfactory agreement of the results was obtained, which confirms the analytical usefulness of the constructed electrodes.

  5. A mouse model for the study of contact-dependent transmission of influenza A virus and the factors that govern transmissibility.

    PubMed

    Edenborough, Kathryn M; Gilbertson, Brad P; Brown, Lorena E

    2012-12-01

    Influenza A virus transmission by direct contact is not well characterized. Here, we describe a mouse model for investigation of factors regulating contact-dependent transmission. Strains within the H3N2 but not H1N1 subtype of influenza virus were transmissible, and reverse-engineered viruses representing hybrids of these subtypes showed that the viral hemagglutinin is a determinant of the transmissible phenotype. Transmission to contact mice occurred within the first 6 to 54 h after cohousing with directly infected index mice, and the proportion of contacts infected within this period was reduced if the index mice had been preinfected with a heterologous subtype virus. A threshold level of virus present in the saliva of the index mice was identified, above which the likelihood of transmission was greatly increased. There was no correlation with transmission and viral loads in the nose or lung. This model could be useful for preclinical evaluation of antiviral and vaccine efficacy in combating contact-dependent transmission of influenza.

  6. Telocyte's contacts.

    PubMed

    Faussone-Pellegrini, Maria-Simonetta; Gherghiceanu, Mihaela

    2016-07-01

    Telocytes (TC) are an interstitial cell type located in the connective tissue of many organs of humans and laboratory mammals. By means of homocellular contacts, TC build a scaffold whose meshes integrity and continuity are guaranteed by those contacts having a mechanical function; those contacts acting as sites of intercellular communication allow exchanging information and spreading signals. Heterocellular contacts between TC and a great variety of cell types give origin to mixed networks. TC, by means of all these types of contacts, their interaction with the extracellular matrix and their vicinity to nerve endings, are part of an integrated system playing tissue/organ-specific roles.

  7. Enhanced attachment of acanthamoeba to extended-wear silicone hydrogel contact lenses: a new risk factor for infection?

    PubMed

    Beattie, Tara K; Tomlinson, Alan; McFadyen, Angus K; Seal, David V; Grimason, Anthony M

    2003-04-01

    To establish if silicone hydrogel (S-H) contact lenses could be a risk factor for Acanthamoeba infection by facilitating the attachment of trophozoites to their surface and transfer to the cornea and to determine the effect Acanthamoeba culture technique, patient wear, and Pseudomonas biofilm coating have on attachment to the S-H lens. Experimental material study. Attachment to a S-H lens was compared with that of a conventional hydrogel control lens. Sixteen replicates were carried out for both lens types under each test condition. Unworn S-H (PureVision; Bausch & Lomb, Kingston-Upon-Thames UK) and conventional hydrogel (Acuvue; Vistakon, Johnson & Johnson, Jacksonville, FL USA) lens quarters were incubated for 90 minutes in suspensions of liquid or plate-cultured Acanthamoeba castellanii trophozoites. Unworn, worn, and Pseudomonas biofilm coated S-H and hydrogel quarters were incubated for 90 minutes with plate-cultured trophozoites. Trophozoites attached to one surface of each lens quarter were counted by direct light microscopy. Logarithmic transformation of data allowed the use of a parametric analysis of variance. Lens polymer had a significant effect on attachment (P < 0.001), with higher numbers of trophozoites attaching to the S-H lens. Culture technique also had a significant effect on attachment (P = 0.013), with higher numbers of liquid-cultured organisms attaching to both lens types. A significant increase in attachment was demonstrated with worn and Pseudomonas biofilm-coated hydrogel lenses (P < 0.001); however, this difference was not seen with the S-H lens. Acanthamoebal attachment to the S-H lenses was significantly greater than to the conventional hydrogel. Liquid-cultured trophozoites demonstrated a higher affinity for the lenses tested. Wear and bacterial biofilm coating had no effect on attachment to S-H lenses. The increased attachment found with the S-H lens may be an inherent characteristic of the polymer or a side effect of the surface

  8. Cell contact as an independent factor modulating cardiac myocyte hypertrophy and survival in long-term primary culture

    NASA Technical Reports Server (NTRS)

    Clark, W. A.; Decker, M. L.; Behnke-Barclay, M.; Janes, D. M.; Decker, R. S.

    1998-01-01

    Cardiac myocytes maintained in cell culture develop hypertrophy both in response to mechanical loading as well as to receptor-mediated signaling mechanisms. However, it has been shown that the hypertrophic response to these stimuli may be modulated through effects of intercellular contact achieved by maintaining cells at different plating densities. In this study, we show that the myocyte plating density affects not only the hypertrophic response and features of the differentiated phenotype of isolated adult myocytes, but also plays a significant role influencing myocyte survival in vitro. The native rod-shaped phenotype of freshly isolated adult myocytes persists in an environment which minimizes myocyte attachment and spreading on the substratum. However, these conditions are not optimal for long-term maintenance of cultured adult cardiac myocytes. Conditions which promote myocyte attachment and spreading on the substratum, on the other hand, also promote the re-establishment of new intercellular contacts between myocytes. These contacts appear to play a significant role in the development of spontaneous activity, which enhances the redevelopment of highly differentiated contractile, junctional, and sarcoplasmic reticulum structures in the cultured adult cardiomyocyte. Although it has previously been shown that adult cardiac myocytes are typically quiescent in culture, the addition of beta-adrenergic agonists stimulates beating and myocyte hypertrophy, and thereby serves to increase the level of intercellular contact as well. However, in densely-plated cultures with intrinsically high levels of intercellular contact, spontaneous contractile activity develops without the addition of beta-adrenergic agonists. In this study, we compare the function, morphology, and natural history of adult feline cardiomyocytes which have been maintained in cultures with different levels of intercellular contact, with and without the addition of beta-adrenergic agonists

  9. Cell contact as an independent factor modulating cardiac myocyte hypertrophy and survival in long-term primary culture

    NASA Technical Reports Server (NTRS)

    Clark, W. A.; Decker, M. L.; Behnke-Barclay, M.; Janes, D. M.; Decker, R. S.

    1998-01-01

    Cardiac myocytes maintained in cell culture develop hypertrophy both in response to mechanical loading as well as to receptor-mediated signaling mechanisms. However, it has been shown that the hypertrophic response to these stimuli may be modulated through effects of intercellular contact achieved by maintaining cells at different plating densities. In this study, we show that the myocyte plating density affects not only the hypertrophic response and features of the differentiated phenotype of isolated adult myocytes, but also plays a significant role influencing myocyte survival in vitro. The native rod-shaped phenotype of freshly isolated adult myocytes persists in an environment which minimizes myocyte attachment and spreading on the substratum. However, these conditions are not optimal for long-term maintenance of cultured adult cardiac myocytes. Conditions which promote myocyte attachment and spreading on the substratum, on the other hand, also promote the re-establishment of new intercellular contacts between myocytes. These contacts appear to play a significant role in the development of spontaneous activity, which enhances the redevelopment of highly differentiated contractile, junctional, and sarcoplasmic reticulum structures in the cultured adult cardiomyocyte. Although it has previously been shown that adult cardiac myocytes are typically quiescent in culture, the addition of beta-adrenergic agonists stimulates beating and myocyte hypertrophy, and thereby serves to increase the level of intercellular contact as well. However, in densely-plated cultures with intrinsically high levels of intercellular contact, spontaneous contractile activity develops without the addition of beta-adrenergic agonists. In this study, we compare the function, morphology, and natural history of adult feline cardiomyocytes which have been maintained in cultures with different levels of intercellular contact, with and without the addition of beta-adrenergic agonists

  10. Water Activity Limits the Hygroscopic Growth Factor of Organic Aerosols

    NASA Astrophysics Data System (ADS)

    Rodriguez, L. I.; Cabrera, J. A.; Golden, D.; Tabazadeh, A.

    2007-12-01

    In this work we study the hygroscopic behavior of organic aerosols, which has important implications for Earth's climate. The hygroscopic growth factor (HGF) is defined as the ratio of the diameter of a spherical particle when it is exposed to dry conditions to that at humid conditions. We present a new formulation to express the HGF of an aerosol particle as a function of water activity (aw) in the aqueous phase. This new formulation matches reported HGFs for common inorganic salts and water-miscible organic particles that are known to deliquesce into aqueous drops at high relative humidities (RH). Many studies use tandem differential mobility analyzers (TDMA) to determine the HGF of organic aerosols. For example, Brooks et al. used a TDMA to measure a HGF of 1.2 for 2 μm phthalic acid (PA) particles at 90% RH (aw= 0.9). However, water activity limits the growth of a particle that can be attributed to water uptake. We have assembled a vapor pressure apparatus to measure aw of aqueous solutions at room temperature. Measured water activities for PA, used in our growth formulation, yield a HGF of ~ 1.0005 for 2 μm PA particles at 90% RH. Comparing our results against Brooks et al. suggests that TDMA experiments may grossly overestimate the HGF of PA particles since water activity limits this growth to below 1.0005. Alternatively, we suggest that the adsorption of a negligible mass of water by a highly porous PA particle can lead to an apparent growth in particle size by changing its morphology. Other studies also use TDMAs to measure HGFs of secondary organic aerosols (SOAs). HGFs reported for SOAs are very similar to PA, suggesting that the observed growth may be due to morphological changes in particle size rather than water uptake as commonly assumed. We built a smog chamber where an organic precursor, such as d-limonene, reacts with nitrogen oxides under UV radiation to produce SOAs. We compare the HGFs for SOAs obtained with our method to those obtained with

  11. Micron-scale Mineral Heterogeneity as a Controlling Factor for Surfactant Adsorption and Water Imbibition in Fractured Shale

    NASA Astrophysics Data System (ADS)

    Ellis, B. R.; Das, S.

    2016-12-01

    This study presents results from a comprehensive analysis of mixed charge surfactants in altering surface properties and water imbibition in fractured shales. Contact angle and surface tension measurements were used to study the change in wettability of Marcellus shale due to interaction with two commonly used surfactants in hydraulic fracturing completion fluids: cationic octadecyl trimethyl ammonium chloride (OTAC) and anionic ammonium Dodecyl Sulfate (ADS). Contact angle measurements of mixed charge surfactant solutions on Marcellus shale samples demonstrate a synergistic interaction of the cationic and anionic surfactants in modifying shale wettability toward a less water-wet state at surfactant concentrations below critical micelle concentration. The role of mineral heterogeneity as a controlling factor for the adsorption mechanism of mixed surfactants in hydraulically fractured shale reservoirs is explored via a combination of atomic and kelvin probe force microscopy. To further explore the impact of mixed surfactant solutions on water uptake in shale gas reservoirs, neutron imaging was used to quantify the rate of water imbibition in fractured shales exposed to a range of surfactant solutions and total surfactant concentrations. Results indicate that mixed charge surfactant solutions can serve to both reduce surface tension and shift shale wettability toward less water-wet conditions due to interaction with positive and negatively charged mineral surfaces in shales. Both of these effects can lead to enhanced natural gas relative permeability and may be associated with observed gas production trends when hydraulic fracturing fluids contain mixed charge surfactant additives.

  12. Water quality, weather and environmental factors associated with fecal indicator organism density in beach sand at two recreational marine beaches.

    PubMed

    Heaney, Christopher D; Exum, Natalie G; Dufour, Alfred P; Brenner, Kristen P; Haugland, Richard A; Chern, Eunice; Schwab, Kellogg J; Love, David C; Serre, Marc L; Noble, Rachel; Wade, Timothy J

    2014-11-01

    Recent studies showing an association between fecal indicator organisms (FIOs) in sand and gastrointestinal (GI) illness among beachgoers with sand contact have important public health implications because of the large numbers of people who recreate at beaches and engage in sand contact activities. Yet, factors that influence fecal pollution in beach sand remain unclear. During the 2007 National Epidemiological and Environmental Assessment of Recreational (NEEAR) Water Study, sand samples were collected at three locations (60 m apart) on weekend days (Sat, Sun) and holidays between June and September at two marine beaches - Fairhope Beach, AL and Goddard Beach, RI - with nearby publicly-owned treatment works (POTWs) outfalls. F(+) coliphage, enterococci, Bacteroidales, fecal Bacteroides spp., and Clostridium spp. were measured in sand using culture and qPCR-based calibrator-cell equivalent methods. Water samples were also collected on the same days, times and transects as the 144 sand samples and were assayed using the same FIO measurements. Weather and environmental data were collected at the time of sample collection. Mean FIO concentrations in sand varied over time, but not space. Enterococci CFU and CCE densities in sand were not correlated, although other FIOs in sand were. The strongest correlation between FIO density in sand and water was fecal Bacteroides CCE, followed by enterococci CFU, Clostridium spp. CCE, and Bacteroidales CCE. Overall, the factors associated with FIO concentrations in sand were related to the sand-water interface (i.e., sand-wetting) and included daily average densities of FIOs in water, rainfall, and wave height. Targeted monitoring that focuses on daily trends of sand FIO variability, combined with information about specific water quality, weather, and environmental factors may inform beach monitoring and management decisions to reduce microbial burdens in beach sand. The views expressed in this paper are those of the authors and do

  13. Water quality, weather and environmental factors associated with fecal indicator organism density in beach sand at two recreational marine beaches

    PubMed Central

    Heaney, Christopher D.; Exum, Natalie G.; Dufour, Alfred P.; Brenner, Kristen P.; Haugland, Richard A.; Chern, Eunice; Schwab, Kellogg J.; Love, David C.; Serre, Marc L.; Noble, Rachel; Wade, Timothy J.

    2015-01-01

    Recent studies showing an association between fecal indicator organisms (FIOs) in sand and gastrointestinal (GI) illness among beachgoers with sand contact have important public health implications because of the large numbers of people who recreate at beaches and engage in sand contact activities. Yet, factors that influence fecal pollution in beach sand remain unclear. During the 2007 National Epidemiological and Environmental Assessment of Recreational (NEEAR) Water Study, sand samples were collected at three locations (60 m apart) on weekend days (Sat, Sun) and holidays between June and September at two marine beaches — Fairhope Beach, AL and Goddard Beach, RI — with nearby publicly-owned treatment works (POTWs) outfalls. F+ coliphage, enterococci, Bacteroidales, fecal Bacteroides spp., and Clostridium spp. were measured in sand using culture and qPCR-based calibrator-cell equivalent methods. Water samples were also collected on the same days, times and transects as the 144 sand samples and were assayed using the same FIO measurements. Weather and environmental data were collected at the time of sample collection. Mean FIO concentrations in sand varied over time, but not space. Enterococci CFU and CCE densities in sand were not correlated, although other FIOs in sand were. The strongest correlation between FIO density in sand and water was fecal Bacteroides CCE, followed by enterococci CFU, Clostridium spp. CCE, and Bacteroidales CCE. Overall, the factors associated with FIO concentrations in sand were related to the sand–water interface (i.e., sand-wetting) and included daily average densities of FIOs in water, rainfall, and wave height. Targeted monitoring that focuses on daily trends of sand FIO variability, combined with information about specific water quality, weather, and environmental factors may inform beach monitoring and management decisions to reduce microbial burdens in beach sand. The views expressed in this paper are those of the authors

  14. Colors and contact dermatitis.

    PubMed

    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.

  15. Airborne allergic contact dermatitis caused by isothiazolinones in water-based paints: a retrospective study of 44 cases.

    PubMed

    Amsler, Emmanuelle; Aerts, Olivier; Raison-Peyron, Nadia; Debons, Michèle; Milpied, Brigitte; Giordano-Labadie, Françoise; Waton, Julie; Ferrier-Le Bouëdec, Marie C; Lartigau, Isabelle; Pecquet, Catherine; Assier, Haudrey; Avenel-Audran, Martine; Bernier, Claire; Castelain, Florence; Collet, Evelyne; Crépy, Marie-Noëlle; Genillier, Nathalie; Girardin, Pascal; Pralong, Pauline; Tetart, Florence; Vital-Durand, Dominique; Soria, Angele; Barbaud, Annick

    2017-09-01

    Airborne allergic contact dermatitis caused by paints containing isothiazolinones has been recognized as a health hazard. To collect epidemiological, clinical and patch test data on airborne allergic contact dermatitis caused by isothiazolinone-containing paints in France and Belgium. A descriptive, retrospective study was initiated by the Dermatology and Allergy Group of the French Society of Dermatology, including methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI)- and/or MI-sensitized patients who developed airborne allergic contact dermatitis following exposure to isothiazolinone-containing paint. Forty-four cases were identified, with mostly non-occupational exposure (79.5%). Of the patients, 22.5% of also had mucosal symptoms. In several cases, the dermatitis required systemic corticosteroids (27.3%), hospitalization (9.1%), and/or sick leave (20.5%). A median delay of 5.5 weeks was necessary to enable patients to enter a freshly painted room without a flare-up of their dermatitis. Approximately one-fifth of the patients knew that they were allergic to MI and/or MCI/MI before the exposure to paints occurred. Our series confirms that airborne allergic contact dermatitis caused by paints containing isothiazolinones is not rare, and may be severe and long-lasting. Better regulation of isothiazolinone concentrations in paints, and their adequate labelling, is urgently needed. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Risk factors, testing and preventative strategies for non-contact injuries in professional football: current perceptions and practices of 44 teams from various premier leagues.

    PubMed

    McCall, Alan; Carling, Chris; Nedelec, Mathieu; Davison, Michael; Le Gall, Franck; Berthoin, Serge; Dupont, Gregory

    2014-09-01

    Little is known about injury prevention practices in professional football clubs. The purpose of this study was therefore to determine the current perceptions and practices of premier league football clubs internationally concerning risk factors, testing and preventative exercises for non-contact injuries. A survey was administered to 93 premier league football clubs internationally. The survey included four sections: (1) persons involved in the injury prevention programme: position, quantity, role, qualification; (2) perceptions regarding non-contact injury risk factors; (3) tests used to identify non-contact injury risk and (4) non-contact injury prevention exercises used, their perceived effectiveness and implementation strategies. 44 surveys were successfully returned (47%). The position of physiotherapist was the most represented position in the injury prevention programme. The top five perceived risk factors in rank order were previous injury, fatigue, muscle imbalance, fitness and movement efficiency. The five most commonly used tests to identify injury risk (in rank order) were functional movement screen, questionnaire, isokinetic dynamometry, physical tests and flexibility. The top five exercises used by clubs were (also in rank order) eccentric exercise, balance/proprioception, hamstring eccentric, core stability and, sharing the fifth position, Nordic hamstring and gluteus activation. The survey revealed the most common perceptions and practices of premier league football clubs internationally regarding risk factors, testing and preventative exercises. The findings can enable reduction of the gap between research and practice. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  17. Opportunistic pathogens relative to physicochemical factors in water storage tanks.

    PubMed

    Al-Bahry, S N; Elshafie, A E; Victor, R; Mahmoud, I Y; Al-Hinai, J A

    2011-06-01

    Household water in Oman, as well as in other countries in the region, is stored in tanks placed on house roofs that can be subjected to physicochemical factors which can promote microbial growth, including pathogens and opportunistic pathogens which pose health risks. Water samples were collected from 30 houses in a heavily populated suburb of Muscat. The tanks used were either glass reinforced plastic (GRP), polyethylene or galvanised iron (GI). Heterotrophic bacteria, coliforms, faecal coliforms and iron sulphur bacteria varied significantly in the three tanks. Yeast and mould count showed significant variations. Isolation of Aeromonas spp., fluorogenic and pathogenic Pseudomonas, Pasteurella, Salmonella, Serratia and Tatumella, and Yersinia and Legionella in biofilms varied in the three tanks. The fungi isolates in the three tanks were Penicillium, Cladosporium and Aspergillus. Nephelometric turbidity unit, threshold odour number and free chlorine varied significantly in the three tanks. True colour unit values did not show a significant difference; however, GRP tanks had algae, autotrophic and pigmented microorganisms. In addition, GI tanks had sediments and corrosion. The results of this investigation are important to evaluate the status of the present household water tanks in countries with high annual temperatures, which may affect public health.

  18. Investigation of Controlling Factors Impacting Water Quality in Shale Gas Produced Brine

    NASA Astrophysics Data System (ADS)

    Fan, W.; Hayes, K. F.; Ellis, B. R.

    2014-12-01

    The recent boom in production of natural gas from unconventional reservoirs has generated a substantial increase in the volume of produced brine that must be properly managed to prevent contamination of fresh water resources. Produced brine, which includes both flowback and formation water, is often highly saline and may contain elevated concentrations of naturally occurring radioactive material and other toxic elements. These characteristics present many challenges with regard to designing effective treatment and disposal strategies for shale gas produced brine. We will present results from a series of batch experiments where crushed samples from two shale formations in the Michigan Basin, the Antrim and Utica-Collingwood shales, were brought into contact with synthetic hydraulic fracturing fluids under in situ temperature and pressure conditions. The Antrim has been an active shale gas play for over three decades, while the Utica-Collingwood formation (a grouped reservoir consisting of the Utica shale and Collingwood limestone) is an emerging shale gas play. The goal of this study is to investigate the influence of water-rock interactions in controlling produced water quality. We evaluate toxic element leaching from shale samples in contact with model hydraulic fracturing fluids under system conditions corresponding to reservoir depths up to 1.5 km. Experimental results have begun to elucidate the relative importance of shale mineralogy, system conditions, and chemical additives in driving changes in produced water quality. Initial results indicate that hydraulic fracturing chemical additives have a strong influence on the extent of leaching of toxic elements from the shale. In particular, pH was a key factor in the release of uranium (U) and divalent metals, highlighting the importance of the mineral buffering capacity of the shale. Low pH values persisted in the Antrim and Utica shale experiments and resulted in higher U extraction efficiencies than that

  19. Gelation of Oil upon Contact with Water: A Bioinspired Scheme for the Self-Repair of Oil Leaks from Underwater Tubes.

    PubMed

    Oh, Hyuntaek; Yaraghi, Nicholas; Raghavan, Srinivasa R

    2015-05-19

    Molecular organogelators convert oils into gels by forming self-assembled fibrous networks. Here, we demonstrate that such gelation can be activated by contacting the oil with an immiscible solvent (water). Our gelator is dibenzylidene sorbitol (DBS), which forms a low-viscosity sol when added to toluene containing a small amount of dimethyl sulfoxide (DMSO). Upon contact with water, DMSO partitions into the water, activating gelation of DBS in the toluene. The gel grows from the oil/water interface and slowly envelops the oil phase. We have exploited this effect for the self-repair of oil leaks from underwater tubes. When a DBS/toluene/DMSO solution flows through the tube, it forms a gel selectively at the leak point, thereby plugging the leak and restoring flow. Our approach is reminiscent of wound-sealing via blood-clotting: there also, inactive gelators in blood are activated at the wound site into a fibrous network, thereby plugging the wound and restoring blood flow.

  20. The fundamental ribosomal RNA transcription initiation factor-IB (TIF-IB, SL1, factor D) binds to the rRNA core promoter primarily by minor groove contacts.

    PubMed

    Geiss, G K; Radebaugh, C A; Paule, M R

    1997-11-14

    Acanthamoeba castellanii transcription initiation factor-IB (TIF-IB) is the TATA-binding protein-containing transcription factor that binds the rRNA promoter to form the committed complex. Minor groove-specific drugs inhibit TIF-IB binding, with higher concentrations needed to disrupt preformed complexes because of drug exclusion by bound TIF-IB. TIF-IB/DNA interactions were mapped by hydroxyl radical and uranyl nitrate footprinting. TIF-IB contacts four minor grooves in its binding site. TIF-IB and DNA wrap around each other in a right-handed superhelix of high pitch, so the upstream and downstream contacts are on opposite faces of the helix. Dimethyl sulfate protection assays revealed limited contact with a few guanines in the major groove. This detailed analysis suggests significant DNA conformation dependence of the interaction.

  1. California Sea Lion (Zalophus californianus) and Harbor Seal (Phoca vitulina richardii) Bites and Contact Abrasions in Open-Water Swimmers: A Series of 11 Cases.

    PubMed

    Nuckton, Thomas J; Simeone, Claire A; Phelps, Roger T

    2015-12-01

    To review cases of bites and contact abrasions in open-water swimmers from California sea lions (Zalophus californianus) and harbor seals (Phoca vitulina richardii). Open-water swimmers from a San Francisco swimming club were questioned about encounters with pinnipeds (seals and sea lions) that resulted in bites or contact abrasions. When possible, wounds were documented with photographs. Medical follow-up and treatment complications were also reviewed. From October 2011 to December 2014, 11 swimmers reported bites by a sea lion (n = 1), harbor seal (n = 7), or unidentified pinniped (n = 3). Ten of the encounters occurred in San Francisco Bay; 1 occurred in the Eld Inlet, in Puget Sound, near Olympia, WA. None of the swimmers were wearing wetsuits. All bites involved the lower extremities; skin was broken in 4 of 11 bites and antibiotics were prescribed in 3 cases. One swimmer, who was bitten by a harbor seal, also had claw scratches. A treatment failure occurred with amoxicillin/clavulanate in another swimmer who was bitten by an unidentified pinniped; the wound healed subsequently with doxycycline, suggesting an infection with Mycoplasma spp. There were no long-lasting consequences from any of the bites. The majority of cases occurred at low tide, and bumping of the swimmer by the animal before or after a bite was common, but no clear tide or attack pattern was identified. Bites and contact abrasions from sea lions and harbor seals are reported infrequently in open-water swimmers and typically involve the lower extremities. Because of the risk of Mycoplasma infection, treatment with a tetracycline is recommended in pinniped bites with signs of infection or serious trauma. Attempting to touch or pet sea lions or seals is inadvisable and prohibited by the Marine Mammal Protection Act. Swimmers should leave the water as soon as possible after a bite or encounter. Copyright © 2015 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  2. Concentrations of Elements in Sediments and Selective Fractions of Sediments, and in Natural Waters in Contact with Sediments from Lake Roosevelt, Washington, September 2004

    USGS Publications Warehouse

    Paulson, Anthony J.; Wagner, Richard J.; Sanzolone, Richard F.; Cox, Steven E.

    2006-01-01

    Twenty-eight composite and replicate sediment samples from 8 Lake Roosevelt sites were collected and analyzed for 10 alkali and alkaline earth elements, 2 non-metals, 20 metals, and 4 lanthanide and actinide elements. All elements were detected in all sediment samples except for silver (95 percent of the elements detected for 1,008 analyses), which was detected only in 4 samples. Sequential selective extraction procedures were performed on single composite samples from the eight sites. The percentage of detections for the 31 elements analyzed ranged from 76 percent for the first extraction fraction using a weak extractant to 93 percent for the four-acid dissolution of the sediments remaining after the third sequential selective extraction. Water samples in various degrees of contact with the sediment were analyzed for 10 alkali and alkaline earth elements, 5 non-metals, 25 metals, and 16 lanthanide and actinide elements. The filtered water samples included 10 samples from the reservoir water column at 8 sites, 32 samples of porewater, 55 samples from reservoir water overlying sediments in 8 cores from the site incubated in a field laboratory, and 24 water samples that were filtered after being tumbled with sediments from 8 sites. Overall, the concentrations of only 37 percent of the 6,776 analyses of the 121 water samples were greater than the reporting limit. Selenium, bismuth, chromium, niobium, silver, and zirconium were not detected in any water samples. The percentage of concentrations for the water samples that were above the reporting limit ranged from 14 percent for the lanthanide and actinide elements to 77 percent for the alkali and alkaline earth elements. Concentrations were greater than reporting limits in only 23 percent of the analyses of reservoir water and 29 percent of the analyses of reservoir water overlying incubation cores. In contrast, 47 and 48 percent of the concentrations of porewater and water samples tumbled with sediments, respectively

  3. Stochastic relaxation of the contact line of a water drop on a solid substrate subjected to white noise vibration: roles of hysteresis.

    PubMed

    Mettu, Srinivas; Chaudhury, Manoj K

    2010-06-01

    Relaxation of the three phase contact line of a sessile drop of water on a low energy surface is studied by subjecting it to a white noise vibration. While a spring force acts on the contact line whenever the contact angle deviates from its equilibrium value, it is opposed by hysteresis. The drop, therefore, remains pinned at a metastable state. With an appropriate amount of vibration, the drop can reach a global equilibrium state irrespective of its initial state, be it advanced or retreated. While the end state is free of hysteresis, the current study sheds light on the dynamics of relaxation that is analyzed in conjunction with a modified Langevin equation. Instead of exhibiting a smooth relaxation as predicted by the Langevin equation with a smooth background potential, stepwise relaxation is observed in most cases. These stepwise relaxations can be explained if the background potential is made slightly corrugated that signifies the existence of metastable states of a drop on a surface. The fluctuation of the displacement of the contact line is highly non-Gaussian. It is shown that an exponential distribution of the displacement fluctuation arises due to the nonlinear hysteresis term in the Langevin equation. The observations of stick-slip motion, the large time of relaxation, and the anomalous displacement fluctuation suggest that hysteresis is present during the relaxation process of the drop even though the final state reached by the drop is free of hysteresis. Finally, we compare the displacement fluctuations of the contact line on two different surfaces: a silicone rubber and a fluorocarbon monolayer. Although the displacement fluctuation is exponential in both cases, the later surface exhibits a greater variance of the distribution than the former plausibly due to differences in hysteresis. This result indicates that the fluctuation of displacement may be used as a tool to study the surface property of a low energy substrate.

  4. Characteristic of the Nanoparticles Formed on the Carbon Steel Surface Contacting with 3d-Metal Water Salt Solutions in the Open-Air System

    NASA Astrophysics Data System (ADS)

    Lavrynenko, O. M.; Pavlenko, O. Yu; Shchukin, Yu S.

    2016-02-01

    The contact of a steel electrode with water dispersion medium in an open-air system leads to the development of various polymorphic iron oxides and oxyhydroxides on the steel surface. Whereas the usage of distilled water causes the obtaining of Fe(II)-Fe(III) layered double hydroxides (green rust) as a primary mineral phase, but in the presence of inorganic 3d-metal water salt solutions, mixed layered double hydroxides (LDHs) together with non-stoichiometric spinel ferrite nanoparticles are formed on the steel surface. Mixed LDHs keep stability against further oxidation and complicate the obtaining of spinel ferrite nanoparticles. Thermal treatment of mixed LDHs among other mineral phases formed via the rotation-corrosion dispergation process at certain temperatures permits to obtain homogenous nanoparticles of spinel ferrites as well as maghemite or hematite doped by 3d-metal cations.

  5. Characteristic of the Nanoparticles Formed on the Carbon Steel Surface Contacting with 3d-Metal Water Salt Solutions in the Open-Air System.

    PubMed

    Lavrynenko, O M; Pavlenko, O Yu; Shchukin, Yu S

    2016-12-01

    The contact of a steel electrode with water dispersion medium in an open-air system leads to the development of various polymorphic iron oxides and oxyhydroxides on the steel surface. Whereas the usage of distilled water causes the obtaining of Fe(II)-Fe(III) layered double hydroxides (green rust) as a primary mineral phase, but in the presence of inorganic 3d-metal water salt solutions, mixed layered double hydroxides (LDHs) together with non-stoichiometric spinel ferrite nanoparticles are formed on the steel surface. Mixed LDHs keep stability against further oxidation and complicate the obtaining of spinel ferrite nanoparticles. Thermal treatment of mixed LDHs among other mineral phases formed via the rotation-corrosion dispergation process at certain temperatures permits to obtain homogenous nanoparticles of spinel ferrites as well as maghemite or hematite doped by 3d-metal cations.

  6. [CHANGING OF PHYSICO-CHEMICAL PARAMETERS OF NON-CONTACT (ELECTROCHEMICAL) ACTIVATED DRINKING WATER IS ASSOCIATED WITH INDUCTION OF GENOMIC INSTABILITY OF CULTIVATED HUMAN BLOOD LYMPHOCYTES].

    PubMed

    Zatsepina, O V; Ingel, F I

    2016-01-01

    In the article there are presented data which are the fragment of large multidisciplinary study of genetic safety of non-contact electrochemically activated water (NAW). The aim of this study was the analysis of the relation of impacts of genomic instability (micronucleus test with cytochalasin B) detected in human blood cells, cultured in medias prepared on the base of these NAWs, with physical and chemical properties of these NaWs. In experiments there were used catholytes and anolytes obtained by activation of osmotic, tap and dining bottled water As a result of such activation, all waters were shown to acquire the ability to induce genomic instability in cellular cultures. Notably in cell cultures on catholytes and anolytes these effects differed between themselves and have been associated with different physical and chemical properties of the NAWs.

  7. Effects of Water Rights and Other Factors on Water Management by Farmers

    NASA Astrophysics Data System (ADS)

    Andriyas, S.; McKee, M.; Hardy, T. B.

    2009-12-01

    Water used for irrigation is a major portion of the total water diversions in the western United States. Depending on irrigation rights and uncertainty in water availability due to variability in the natural hydrological cycle, significant cuts in irrigation supply can result in low-flow years. Irrigators respond to these and other uncertainties (e.g., future potential yields and commodity prices) in their decisions on the allocation of inputs to farm production, including irrigation water. This paper seeks to understand the determinants in farmers’ decisions to irrigate, and presents the results of an analysis of the behavior of irrigators with respect to their day-by-day irrigation decisions. The analyses are based on the use of agent-based models that simulate crop growth, evapotranspiration, soil moisture balance, and irrigator behavior and decision-making. The study site is located near Delta, Utah, and involves farms on approximately 30 square miles of irrigated land. The analyses address factors such as stage of crop growth, crop health, financial constraints, climatic conditions, and opportunity for leasing of water.

  8. Risk factors for contacts between wild boar and outdoor pigs in Switzerland and investigations on potential Brucella suis spill-over

    PubMed Central

    2012-01-01

    Background Due to the parallel increase of the number of free-ranging wild boar and domestic pigs reared outdoor, the risk that they interact has become higher. Contacts with wild boar can be the origin of disease outbreaks in pigs, as it has been documented for brucellosis in some European countries. This study aimed at quantifying the occurrence of contacts between wild boar and outdoor domestic pigs in Switzerland, and identifying risk factors for these contacts. Furthermore, exposed pigs were tested for pathogen spill-over, taking Brucella suis as an example because B. suis is widespread in Swiss wild boar while domestic pigs are officially free of brucellosis. Results Thirty-one percent of the game-wardens and 25% of the pig owners participating to a country-wide questionnaire survey reported contacts, including approaches of wild boar outside the fence, intrusions, and mating. Seventeen piggeries (5%) reported the birth of cross-bred animals. Risk factors for contacts identified by a uni- and multivariable logistic regression approach were: distance between pigs enclosure and houses, proximity of a forest, electric fences, and fences ≤ 60 cm. Pigs of the Mangalitza breed were most at risk for mating with wild boar (births of cross-bred animals). Blood and tissues of 218 outdoor pigs from 13 piggeries were tested for an infection with Brucella suis, using rose bengal test, complement fixation test, and an IS711-based real-time PCR. One piggery with previous wild boar contacts was found infected with B. suis, however, epidemiological investigations failed to identify the direct source of infection. Conclusions Results show that interactions between wild boar and outdoor pigs are not uncommon, pointing at the existing risk of pathogen spill-over. Provided data on risk factors for these interactions could help the risk-based implementation of protection measures for piggeries. The documentation of a brucellosis outbreak in pigs despite the freedom

  9. Thermal Treatment Temperature and Time Dependence of Contact Angle of Water on Fluorinated Polystyrene as Hydrophobic Film Coating

    NASA Astrophysics Data System (ADS)

    Tolentino, M. S.; Carpena, J. F.; Javier, R. M.; Aquino, R. R.

    2017-06-01

    The study focuses on the synthesis of fluorinated polystyrene (F-PS) as a hydrophobic film coating and on the investigation of the consequent effects of thermal treatment time and treatment temperature on its contact angle. The fluorinated polystyrene is synthesized via Friedel-Crafts acylation of the benzoic rings by electrophilic substitution of trifluoroacetic anhydride in the presence of AlCl3 in an environment of dichloromethane as the aprotic solvent with a reaction temperature of 36°C. The reaction yielded fluorinated polystyrene characterized by a solid brown substance. FT-IR analysis of the substance had shown band peaks at 1150 cm-1, a wavenumber indicating the presence of fluorine in the synthesized material, which lowers its surface energy. SEM images of the F-PS show nucleation sites giving rise to hierarchical structures on the surface of the material due to the action of fluorination. The contact angle of fluorinated polystyrene, upon application of thermal treatment, increased to as much as 29.26% when compared to the unmodified polystyrene manifesting a preferentially more hydrophobic behavior. It was also found that the contact angle increases linearly with treatment temperature while statistical analysis shows that thermal treatment time has no significant effect on the hydrophobicity of the F- PS.

  10. Prevention of non-contact anterior cruciate ligament injuries in soccer players. Part 1: Mechanisms of injury and underlying risk factors.

    PubMed

    Alentorn-Geli, Eduard; Myer, Gregory D; Silvers, Holly J; Samitier, Gonzalo; Romero, Daniel; Lázaro-Haro, Cristina; Cugat, Ramón

    2009-07-01

    Soccer is the most commonly played sport in the world, with an estimated 265 million active soccer players by 2006. Inherent to this sport is the higher risk of injury to the anterior cruciate ligament (ACL) relative to other sports. ACL injury causes the most time lost from competition in soccer which has influenced a strong research focus to determine the risk factors for injury. This research emphasis has afforded a rapid influx of literature defining potential modifiable and non-modifiable risk factors that increase the risk of injury. The purpose of the current review is to sequence the most recent literature that reports potential mechanisms and risk factors for non-contact ACL injury in soccer players. Most ACL tears in soccer players are non-contact in nature. Common playing situations precluding a non-contact ACL injury include: change of direction or cutting maneuvers combined with deceleration, landing from a jump in or near full extension, and pivoting with knee near full extension and a planted foot. The most common non-contact ACL injury mechanism include a deceleration task with high knee internal extension torque (with or without perturbation) combined with dynamic valgus rotation with the body weight shifted over the injured leg and the plantar surface of the foot fixed flat on the playing surface. Potential extrinsic non-contact ACL injury risk factors include: dry weather and surface, and artificial surface instead of natural grass. Commonly purported intrinsic risk factors include: generalized and specific knee joint laxity, small and narrow intercondylar notch width (ratio of notch width to the diameter and cross sectional area of the ACL), pre-ovulatory phase of menstrual cycle in females not using oral contraceptives, decreased relative (to quadriceps) hamstring strength and recruitment, muscular fatigue by altering neuromuscular control, decreased "core" strength and proprioception, low trunk, hip, and knee flexion angles, and high

  11. Perception of drinking water safety and factors influencing acceptance and sustainability of a water quality intervention in rural southern India.

    PubMed

    Francis, Mark Rohit; Nagarajan, Guru; Sarkar, Rajiv; Mohan, Venkata Raghava; Kang, Gagandeep; Balraj, Vinohar

    2015-07-30

    Acceptance and long-term sustainability of water quality interventions are pivotal to realizing continued health benefits. However, there is limited research attempting to understand the factors that influence compliance to or adoption of such interventions. Eight focus group discussions with parents of young children--including compliant and not compliant households participating in an intervention study, and three key-informant interviews with village headmen were conducted between April and May 2014 to understand perceptions on the effects of unsafe water on health, household drinking water treatment practices, and the factors influencing acceptance and sustainability of an ongoing water quality intervention in a rural population of southern India. The ability to recognize health benefits from the intervention, ease of access to water distribution centers and the willingness to pay for intervention maintenance were factors facilitating acceptance and sustainability of the water quality intervention. On the other hand, faulty perceptions on water treatment, lack of knowledge about health hazards associated with drinking unsafe water, false sense of protection from locally available water, resistance to change in taste or odor of water and a lack of support from male members of the household were important factors impeding acceptance and long term use of the intervention. This study highlights the need to effectively involve communities at important stages of implementation for long term success of water quality interventions. Timely research on the factors influencing uptake of water quality interventions prior to implementation will ensure greater acceptance and sustainability of such interventions in low income settings.

  12. Risk factors for water sports-related cervical spine injuries.

    PubMed

    Chang, Spencer K Y; Tominaga, Gail T; Wong, Jan H; Weldon, Edward J; Kaan, Kenneth T

    2006-05-01

    To examine risk factors associated with water sports-related cervical spine injuries (WSCSI). A retrospective analysis of all patients admitted for WSCSI from 1993 to 1997 was performed. The severity of cervical spine injury was assessed by review of medical records and imaging studies. Mechanisms of injury and activities at the time of injury were noted to determine risk factors for cervical spine injuries caused by wave forced impacts (WFI) from activities such as bodysurfing and body boarding. These risks were compared with injuries incurred by shallow water dives (SWD). One hundred patients were analyzed (mean age, 36 years old); 89% were male, 62% were nonresidents of Hawaii, and 75% had a large build. Patients without radiographic evidence of fractures, subluxations, and/or dislocations (n = 26) were significantly older (48 versus 32 years old, p < 0.0001) with a higher rate of pre-existing cervical spine abnormalities (65% versus 15%, p < 0.0001) compared with the remainder of patients (n = 74). Seventy-seven percent of WFI involved nonresidents. The mean age of WFI patients was significantly older than patients involved in SWD (42 versus 25 years). Ninety-six percent of wave-related accidents occurred at moderately to severely rated shorebreak beaches. Wave forced impacts of the head with the ocean bottom typically occurred at moderate to severe shorebreaks, and involved inexperienced, large-build males in their 40s. Spinal stenosis and degenerative spondylosis may increase the risk of cervical spine injury associated with WFI due to the increased risk of neck hyperextension and hyperflexion impacts inherent to this activity.

  13. Geochemical factors controlling free Cu ion concentrations in river water

    NASA Astrophysics Data System (ADS)

    Rozan, Tim F.; Benoit, Gaboury

    1999-10-01

    Copper speciation was determined monthly at seven sites on four rivers in southern New England to understand which geochemical factors control free metal ion concentrations in river water. Samples were conventionally filtered (<0.45 μm) and then ultrafiltered (3.000 molecular weight cut-off) to determine Cu speciation in the truly dissolved size fraction. Differential pulse anodic stripping voltammetry (DPASV) was used to quantify natural organic complexation and cathodic stripping square wave voltammetry (CSSWV) to measure directly both Cu sulfide complexes and total EDTA concentrations. The results showed both dissolved organic matter (DOM) and sulfide complexation dominate Cu speciation and control the concentrations of free ion. Free Cu2+ was calculated to be in the subnanomolar range for the majority of the year. Only in the winter months, when concentrations of DOM and metal sulfides complexes were at a minimum were free metal ions directly measurable by DPASV at low nanomolar concentrations. The extent of sulfide complexation appears to be dominated by the size of headwater marshes (upstream sampling sites) and by the amount of sewage treatment plant effluent (downstream sites). DOM complexation was related to the organic matter composition and followed model organic ligands. Indirect evidence suggests variations in river water pH and Ca2+ (metal competition) has only a minor role in Cu complexation. Measured concentrations of total EDTA suggest this synthetic ligand can control Cu speciation in some highly developed watersheds; however, competition from Ni (and possibly Fe) limits the extent of this complexation.

  14. Characterizing hydrophobicity of amino acid side chains in a protein environment via measuring contact angle of a water nanodroplet on planar peptide network

    PubMed Central

    Zhu, Chongqin; Gao, Yurui; Li, Hui; Meng, Sheng; Li, Lei; Francisco, Joseph S.; Zeng, Xiao Cheng

    2016-01-01

    Hydrophobicity of macroscopic planar surface is conventionally characterized by the contact angle of water droplets. However, this engineering measurement cannot be directly extended to surfaces of proteins, due to the nanometer scale of amino acids and inherent nonplanar structures. To measure the hydrophobicity of side chains of proteins quantitatively, numerous parameters were developed to characterize behavior of hydrophobic solvation. However, consistency among these parameters is not always apparent. Herein, we demonstrate an alternative way of characterizing hydrophobicity of amino acid side chains in a protein environment by constructing a monolayer of amino acids (i.e., artificial planar peptide network) according to the primary and the β-sheet secondary structures of protein so that the conventional engineering measurement of the contact angle of a water droplet can be brought to bear. Using molecular dynamics simulations, contact angles θ of a water nanodroplet on the planar peptide network, together with excess chemical potentials of purely repulsive methane-sized Weeks−Chandler−Andersen solute, are computed. All of the 20 types of amino acids and the corresponding planar peptide networks are studied. Expectedly, all of the planar peptide networks with nonpolar amino acids are hydrophobic due to θ > 90°, whereas all of the planar peptide networks of the polar and charged amino acids are hydrophilic due to θ < 90°. Planar peptide networks of the charged amino acids exhibit complete-wetting behavior due to θ = 0°. This computational approach for characterization of hydrophobicity can be extended to artificial planar networks of other soft matter. PMID:27803319

  15. Characterizing hydrophobicity of amino acid side chains in a protein environment via measuring contact angle of a water nanodroplet on planar peptide network.

    PubMed

    Zhu, Chongqin; Gao, Yurui; Li, Hui; Meng, Sheng; Li, Lei; Francisco, Joseph S; Zeng, Xiao Cheng

    2016-11-15

    Hydrophobicity of macroscopic planar surface is conventionally characterized by the contact angle of water droplets. However, this engineering measurement cannot be directly extended to surfaces of proteins, due to the nanometer scale of amino acids and inherent nonplanar structures. To measure the hydrophobicity of side chains of proteins quantitatively, numerous parameters were developed to characterize behavior of hydrophobic solvation. However, consistency among these parameters is not always apparent. Herein, we demonstrate an alternative way of characterizing hydrophobicity of amino acid side chains in a protein environment by constructing a monolayer of amino acids (i.e., artificial planar peptide network) according to the primary and the β-sheet secondary structures of protein so that the conventional engineering measurement of the contact angle of a water droplet can be brought to bear. Using molecular dynamics simulations, contact angles θ of a water nanodroplet on the planar peptide network, together with excess chemical potentials of purely repulsive methane-sized Weeks-Chandler-Andersen solute, are computed. All of the 20 types of amino acids and the corresponding planar peptide networks are studied. Expectedly, all of the planar peptide networks with nonpolar amino acids are hydrophobic due to θ [Formula: see text] 90°, whereas all of the planar peptide networks of the polar and charged amino acids are hydrophilic due to θ [Formula: see text] 90°. Planar peptide networks of the charged amino acids exhibit complete-wetting behavior due to θ [Formula: see text] 0°. This computational approach for characterization of hydrophobicity can be extended to artificial planar networks of other soft matter.

  16. Determination of microcystin-LR in waters in the subnanomolar range by sol-gel imprinted polymers on solid contact electrodes.

    PubMed

    Queirós, Raquel B; Noronha, João P; Marques, Paulo V S; Fernandes, João S; Sales, M Goreti F

    2012-05-21

    The present work reports new sensors for the direct determination of Microcystin-LR (MC-LR) in environmental waters. Both selective membrane and solid contact were optimized to ensure suitable analytical features in potentiometric transduction. The sensing layer consisted of Imprinted Sol-Gel (ISG) materials capable of establishing surface interactions with MC-LR. Non-Imprinted Sol-Gel (NISG) membranes were used as negative control. The effects of an ionic lipophilic additive, time of sol-gel polymerization, time of extraction of MC-LR from the sensitive layer, and pH were also studied. The solid contact was made of carbon, aluminium, titanium, copper or nickel/chromium alloys (80 : 20 or 90 : 10). The best ISG sensor had a carbon solid contact and displayed average slopes of 211.3 mV per decade, with detection limits of 7.3 × 10(-10) M, corresponding to 0.75 μg L(-1). It showed linear responses in the range of 7.7 × 10(-10) to 1.9 × 10(-9) M of MC-LR (corresponding to 0.77-2.00 μg L(-1)), thus including the limiting value for MC-LR in waters (1.0 μg L(-1)). The potentiometric-selectivity coefficients were assessed by the matched potential method for ionic species regularly found in waters up to their limiting levels. Chloride (Cl(-)) showed limited interference while aluminium (Al(3+)), ammonium (NH(4)(+)), magnesium (Mg(2+)), manganese (Mn(2+)), sodium (Na(+)), and sulfate (SO(4)(2-)) were unable to cause the required potential change. Spiked solutions were tested with the proposed sensor. The relative errors and standard deviation obtained confirmed the accuracy and precision of the method. It also offered the advantages of low cost, portability, easy operation and suitability for adaptation to flow methods.

  17. Experimental study on latent heat storage characteristics of W/O emulsion -Supercooling rate of dispersed water drops by direct contact heat exchange-

    NASA Astrophysics Data System (ADS)

    Morita, Shin-ichi; Hayamizu, Yasutaka; Horibe, Akihiko; Haruki, Naoto; Inaba, Hideo

    2013-04-01

    Recently, much attention has been paid to investigate the latent heat storage system. Using of ice heat storage system brings an equalization of electric power demand, because it will solved the electric -power-demand-concentration on day-time of summer by the air conditioning. The flowable latent heat storage material, Oil/Water type emulsion, microencapsulated latent heat material-water mixture or ice slurry, etc., is enable to transport the latent heat in a pipe. The flowable latent heat storage material can realize the pipe size reduction and system efficiency improvement. Supercooling phenomenon of the dispersed latent heat storage material in continuous phase brings the obstruction of latent heat storage. The latent heat storage rates of dispersed water drops in W/O (Water/Oil) emulsion are investigated experimentally in this study. The water drops in emulsion has the diameter within 3 ˜ 25μm, the averaged water drop diameter is 7.3μm and the standard deviation is 2.9μm. The direct contact heat exchange method is chosen as the phase change rate evaluation of water drops in W/O emulsion. The supercooled temperature and the cooling rate are set as parameters of this study. The evaluation is performed by comparison between the results of this study and the past research. The obtained experimental result is shown that the 35K or more degree from melting point brings 100% latent heat storage rate of W/O emulsion. It was clarified that the supercooling rate of dispersed water particles in emulsion shows the larger value than that of the bulk water.

  18. Sector-wise midpoint characterization factors for impact assessment of regional consumptive and degradative water use.

    PubMed

    Lin, Chia-Chun; Lin, Jia-Yu; Lee, Mengshan; Chiueh, Pei-Te

    2017-12-31

    Water availability, resulting from either a lack of water or poor water quality is a key factor contributing to regional water stress. This study proposes a set of sector-wise characterization factors (CFs), namely consumptive and degradative water stresses, to assess the impact of water withdrawals with a life cycle assessment approach. These CFs consider water availability, water quality, and competition for water between domestic, agricultural and industrial sectors and ecosystem at the watershed level. CFs were applied to a case study of regional water management of industrial water withdrawals in Taiwan to show that both regional or seasonal decrease in water availability contributes to a high consumptive water stress, whereas water scarcity due to degraded water quality not meeting sector standards has little influence on increased degradative water stress. Degradative water stress was observed more in the agricultural sector than in the industrial sector, which implies that the agriculture sector may have water quality concerns. Reducing water intensity and alleviating regional scale water stresses of watersheds are suggested as approaches to decrease the impact of both consumptive and degradative water use. The results from this study may enable a more detailed sector-wise analysis of water stress and influence water resource management policies. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Thermal contact resistance at the Nb/Cu interface as a limiting factor for sputtered thin film RF superconducting cavities

    NASA Astrophysics Data System (ADS)

    Palmieri, V.; Vaglio, R.

    2016-01-01

    The ‘Q-slope’ problem has so far strongly limited the application of niobium thin film sputtered copper cavities in high field accelerators. In the present paper, based on experimental evidence, we consider the hypothesis that the Q-slope is related to enhanced thermal boundary resistance R Nb/Cu at the Nb/Cu interface, due to poor thermal contact between film and substrate. We have developed a simple model that directly connects the Q versus E acc curves to the distribution function f(R Nb/Cu) of R Nb/Cu values at the Nb/Cu interface over the cavity surface. Starting from different Q versus E acc experimental curves from different sources, using typical ‘inverse problem’ methods, we deduce the corresponding distribution functions generating those curves. The results show, for all the examined cases, very similar functional dependences of f(R Nb/Cu) and prove that, to describe the experimental Q versus E acc curves, it is sufficient to assume that only a small fraction of the film over the cavity surface is in poor thermal contact with the substrate. The whole body of information and data reported seems to indicate that the main origin of the Q-slope in thin film cavities is related to bad adhesion at the Nb/Cu interface. Strategies to solve the Q-slope problem improving the film adhesion are finally delineated.

  20. [Children of the GAZEL Cohort: I--Prevalence of contacts with the medico-educational system for psychological reasons, and associated factors].

    PubMed

    Fombonne, E; Vermeersch, S

    1997-03-01

    An epidemiological survey of French children aged 4 to 16 was conducted in order to estimate the 12-months rates of service utilization for psychological reasons and to assess the factors associated with service use in this community sample. A large sample of 2582 children and adolescents was recruited from the families whose one parent was employed by the national electricity and gaz company (EDF-GDF). Of these employees, 20,000 have volunteered for a long-term prospective cohort study of their health and, since 1989, they have participated to annual surveys and additional ad hoc research programmes. Families with a child aged 4 to 16 in 1991 were selected. Only one child was selected in each family, and the sample was stratified by socio-economic status and family size according to census data. A survey questionnaire comprising a valid measure of child psychopathology (Child Behavior Checklist: CBCL) and an additional questionnaire including questions related to service use was used as a means of data collection. The response rate was 62.2% and factors associated with participation in the survey were analysed. The 12-months prevalence rate of contact for psychological motives were: 42.3% for general practitioners and family doctors, 7.8% for speech and language therapists, 9.5% for educational specialists, and 6.0% for mental health professionals. With the exception of general practitioners, rates of service contact were significantly higher for boys. Logistic regression analysis was used to identify separately factors associated with recent contact for each category of professionals. Results showed that, for all professionals, high scores on the CBCL measure was significantly associated with service use, the strongest association being found for mental health professionals. Family structure was also predictive of the latter, with higher rates of contacts for those children living in families whose parents are divorced, separated or widowed. Some differences for

  1. Flow visualization and void fraction measurement in liquid-metal/water direct contact heat exchange by X-ray attenuation technique

    NASA Astrophysics Data System (ADS)

    Liu, Xin

    One concept being considered for steam generation in particular next generation nuclear reactor designs, involves water coming into direct contact with a circulating molten metal. To optimize the design of such direct contact heat exchange and vaporization systems, detailed knowledge is necessary of the various flow regimes, interfacial transport phenomena, heat transfer and operational stability. With the development of high performance digital detectors, radiography using X-rays or neutrons maybe a suitable technique to obtain information about that direct-contact interaction; i.e., void volume fractions, length scales and dynamic behavior. Under the basis of previous investigations, a complete methodology of the X-ray radiography for two-phase flow measurement has been developed from the facility and imaging analysis aspects. Through this developed methodology, a high energy X-ray imaging system is optimized for the direct-contact heat exchange experiment. Beside an on-line calibration procedure which practically quantifies the imaging system's performance, the extended linear system theory and Rose's model have also been used to evaluate the imaging system's performance, respectively. The bottleneck of the current imaging system and the future of system improvement direction have been pointed out. With our real-time, large-area high energy X-ray imaging system, the two-phase flow was visualized and stored digitally. An efficient image processing strategy has also been established by combining several optimal digital image processing algorithms. The approach has been implemented into a software computational tool written in MATLAB called T-XIP. Time-dependent heat transfer related variables, such as void fraction (void volume), local heat transfer coefficient, etc., were calculated using this software tool. Finally, an error analysis associated with the void fraction measurement has been given based on two procedures.

  2. Therapeutic Array Transducer Element Using Coresonance between Hemispherical Piezoceramic Shell and Water Sphere: Effect of Load Masses of Support and Electric Contact

    NASA Astrophysics Data System (ADS)

    Otsu, Kenji; Yoshizawa, Shin; Umemura, Shin-ichiro

    2012-07-01

    For therapeutic ultrasound array transducers, it is necessary to reduce the electrical impedance of their elements so that the transducer can produce high ultrasonic power at a relatively low drive voltage. For this purpose, a new concept of a breathing-mode piezoceramic transducer element has been proposed. Numerical simulation showed its low electric impedance as well as good acoustical coupling between the concave hemispherical piezoceramic shell, with a diameter on the order of a wavelength in water, and the volume of a water sphere half enclosed by the shell. In the preparation of a prototype transducer, the effect of additional load masses of the flange supporting the shell and the electric contact for driving the element was numerically analyzed in this paper.

  3. Degradation of Remazol Red in batik dye waste water by contact glow discharge electrolysis method using NaOH and NaCl electrolytes

    NASA Astrophysics Data System (ADS)

    Saksono, Nelson; Putri, Dita Amelia; Suminar, Dian Ratna

    2017-03-01

    Contact Glow Discharge Electrolysis (CGDE) method is one of Plasma Electrolysis technology which has been approved to degrade organic waste water because it is very productive in producing hydroxyl radical. This study aims to degrade Remazol Red by CGDE method and evaluate important parameters that have influent in degradation process of Remazol Red in Batik dye waste water in batch system. The kind of electrolyte (acid and base) and the addition of metal ion such as Fe2+ have affected Remazol Red degradation percentage. Ultraviolet-Visible (UV-Vis) absorption spectra were used to monitor the degradation process. The result of study showed that percentage degradation was 99.97% which obtained by using NaCl 0.02 M with addition Fe2+ 20 ppm, applied voltage 700 volt, anode depth 0.5 cm, initial concentration of Remazol Red 250 ppm and the temperature of solutions was maintained 50-60 ˚C.

  4. Geochemical factors controlling free Cu ion concentrations in river water

    SciTech Connect

    Rozan, T.F.; Benoit, G.

    1999-10-01

    Copper speciation was determined monthly at seven sites on four rivers in southern New England to understand which geochemical factors control free metal ion concentrations in river water. Samples were conventionally filtered ({lt}0.45 {micro}m) and then ultrafiltered (3.000 molecular weight cut-off) to determine Cu speciation in the truly dissolved size fraction. Differential pulse anodic stripping voltammetry (DPASV) was used to quantify natural organic complexation and cathodic stripping square wave voltammetry (CSSWV) to measure directly both Cu sulfide complexes and total EDTA concentrations. The results showed both dissolved organic matter (DOM) and sulfide complexation dominate Cu speciation and control the concentrations of free ion. Free Cu{sup 2+} was calculated to be in the subnanomolar range for the majority of the year. Only in the winter months, when concentrations of DOM and metal sulfides complexes were at a minimum were free metal ions directly measurable by DPASV at low nanomolar concentrations. The extent of sulfide complexation appears to be dominated by the size of headwater marshes (upstream sampling sites) and by the amount of sewage treatment plant effluent (downstream sites). DOM complexation was related to the organic matter composition and followed model organic ligands. Indirect evidence suggests variations in river water pH and Ca{sup 2+} (metal competition) has only a minor role in Cu complexation. Measured concentrations of total EDTA suggest this synthetic ligand can control Cu speciation in some highly developed watersheds; however, competition from Ni (and possibly Fe) limits the extent of this complexation.

  5. Validation of Capillarity Theory at the Nanometer Scale by Atomistic Computer Simulations of Water Droplets and Bridges in Contact with Hydrophobic and Hydrophilic Surfaces

    NASA Astrophysics Data System (ADS)

    Giovambattista, Nicolas; Almeida, Alexandre; Alenkar, Adriano; Buldyrev, Sergey

    Capillarity is the study of interfaces between two immiscible liquids or between a liquid and a vapor. Capillarity theory (CT) was created in the early 1800s and it is applicable to macroscopic (>1 μm) systems. In general, macroscopic theories are expected to fail at <10 nm scales where molecular details may become relevant. We show that, surprisingly, CT provides satisfactory predictions at 210 nm scales. Specifically, we perform atomistic molecular dynamics (MD) simulations of water droplets and capillary bridges of different symmetry in contact with various surfaces. The surfaces correspond to hydroxilated silica, modified to cover a wide range of hydrophobicity/hydrophilicity. In agreement with CT, it is found that (i) water contact angle is independent of the droplet/bridge geometry and depends only on the surface employed; (ii) CT provides the correct droplet/bridge profile for all hydrophobic/hydrophilic surfaces considered; and, remarkably, (iii) CT works even for the very small droplets/bridges studied, for which the smallest dimension is ~2 nm. We confirm the self-consistency of CT at 210 nm scales by calculating the capillary forces between different surfaces induced by capillary bridges; the agreement between MD simulations and CT theory is remarkable

  6. Wettability-Water/brine Film Thickness Relationship and the Effect of Supercritical CO2 Pre-contact for CO2/brine/mineral Systems under Geologic CO2 Sequestration Conditions: Insights from Molecular Dynamics Simulations

    NASA Astrophysics Data System (ADS)

    Chen, C.; Song, Y.; Li, W.

    2016-12-01

    Injection CO2 into deep saline aquifers is one of the main options for geologic carbon sequestration (GCS). A successful GCS in saline aquifers requires full knowledge about CO2/brine/mineral systems under sequestration conditions to reduce uncertainties during subsurface storage of CO2. Adsorbed water film thickness and wettability on mineral surfaces are two key characteristics for CO2/brine/mineral systems. Wettability and water/brine film thickness have been measured experimentally and predicted by molecular simulation (MD) studies. However, these studies only consider the films apart from contact angles. Investigations on wettability for CO2/brine/mineral systems only consider contact angles without measurements on film thickness. The relationship between film thicknesses with water contact angles is open to questions. In this paper, MD simulations have been performed to investigate the interrelationship between water film thicknesses and water contact angles. Three silica surfaces with different silanol group number densities (Q3, Q3-50%, Q3/Q4) were selected to represent silica surfaces with different wettabilities. We found that as water contact angle increases, the film thickness decreases. We also studied the effect of CO2-mineral pre-contact and found that: on Q3 surface, if a CO2 bubble was pre-contacted with the surface, it can remain on the surface without forming a water film; however, if a CO2 bubble was placed certain distances away from the surface, it formed a water film. Wettability analysis revealed that on the same surface, water contact angle was larger when there was no water film. These findings show that on some silica surfaces, water film may be destroyed by supercritical CO2 even the silica surfaces are hydrophilic. A water film rupture mechanism was propsed for CO2 adhesion on mineral surfaces [Wang (2013) Environ. Sci. Technol. 47, 11858; Zhang (2016) Environ. Sci. Technol. Lett. 10.1021/acs.estlett.5b00359]. The rupture of water film

  7. Nasal carriage of Staphylococcus aureus in healthy humans with different levels of contact with animals in Tunisia: genetic lineages, methicillin resistance, and virulence factors.

    PubMed

    Ben Slama, K; Gharsa, H; Klibi, N; Jouini, A; Lozano, C; Gómez-Sanz, E; Zarazaga, M; Boudabous, A; Torres, C

    2011-04-01

    Nasal swabs of 423 healthy humans who showed different levels of contact with animals (frequent, 168; sporadic, 94; no contact, 161) were obtained in Tunisia (2008-2009), and 99 of them presented other associated risk factors. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in one of these 423 samples (0.24%), retrieved from a veterinarian. The MRSA isolate was mecA-positive, typed as ST80-t203-SCCmecIVc-agrIII, and contained tet(K), ant(6)-Ia, and aph(3')-IIIa genes encoding tetracycline, streptomycin, and kanamycin resistance, respectively. This MRSA isolate also contained the lukF/lukS virulence gene encoding Panton-Valentine leukocidin. Fifty-four (12.8%) additional nasal samples contained methicillin-susceptible S. aureus (MSSA) and one isolate/sample was characterized. A high diversity of spa types (n = 43; 4 new) and pulsed-field gel electrophoresis (PFGE) types (n = 37) was detected among the 55 recovered S. aureus strains. The percentages of antimicrobial resistance/detected resistance genes were as follows: tetracycline [22%/tet(K)-tet(L)-tet(M)], erythromycin [5%/msrA], ciprofloxacin [14.5%], trimethoprim-sulfamethoxazole [2%/dfrA], streptomycin [11%/ant(6)-Ia], kanamycin [7%/aph(3')-IIIa], amikacin [5%], and chloramphenicol [2%]. Four and two isolates carried the lukF/lukS and eta and/or etb genes, respectively, and always in individuals with contact with animals. Eleven isolates carried the tst gene and were recovered from individuals with different levels of contact with animals.

  8. Fundamental Study on Enhancement of Liquid-Liquid Direct Contact Heat Transfer of Descending Water Insoluble High Density Liquid Droplets in a Heat Source Water Layer by Using Wire Mesh as Dispersion Material

    NASA Astrophysics Data System (ADS)

    Inaba, Hideo; Horibe, Akihiko; Yokoyama, Naoki; Haruki, Naoto

    This paper has dealt with liquid-liquid direct contact heat transfer characteristics by means of water insoluble heat transfer medium. In the present study, Perfluorocarbon(PFC, density of 1830kg/m3)was injected from above into a hot water layer, which was mounted by stainless steel wire net in order to make PFC droplets finer. The measuring result of the drop let diameter revealed that the droplet size distribution exerted an influence on the temperature effectiveness between PFC droplets and the hot water layer. It was observed that PFC droplets were dispersed by collision with stainless steel wire nets during falling in the hot water layer. Finally correlations equations of the temperature effectiveness and average diameter of PFC droplets had been derived as a function of some parameters.

  9. Air-coupled broadband ultrasonic spectroscopy as a new non-invasive and non-contact method for the determination of leaf water status.

    PubMed

    Sancho-Knapik, Domingo; Gómez Alvarez-Arenas, Tomás; Peguero-Pina, José Javier; Gil-Pelegrín, Eustaquio

    2010-03-01

    The implementation of non-destructive methods for the study of water changes within plant tissues and/or organs has been a target for some time in plant physiology. Recent advances in air-coupled ultrasonic spectroscopy have enabled ultrasonic waves to be applied to the on-line and real-time assessment of the water content of different materials. In this study, this technique has been applied as a non-destructive, non-invasive, non-contact, and repeatable method for the determination of water status in Populusxeuramericana and Prunus laurocerasus leaves. Frequency spectra of the transmittance of ultrasounds through plant leaves reveal the presence of at least one resonance. At this resonant frequency, transmittance is at its maximum. This work demonstrates that changes in leaf relative water content (RWC) and water potential (Psi) for both species can be accurately monitored by the corresponding changes in resonant frequency. The differential response found between both species may be due to the contrasting leaf structural features and the differences found in the parameters derived from the P-V curves. The turgor loss point has been precisely defined by this new technique, as it is derived from the lack of significant differences between the relative water content at the turgor loss point (RWC(TLP)) obtained from P-V curves and ultrasonic measurements. The measurement of the turgor gradient between two different points of a naturally transpiring leaf is easily carried out with the method introduced here. Therefore, such a procedure can be an accurate tool for the study of all processes where changes in leaf water status are involved.

  10. Development of water requirement factors for biomass conversion pathway.

    PubMed

    Singh, Shikhar; Kumar, Amit

    2011-01-01

    Published data were used to develop an integrated spreadsheet-based model to estimate total water requirement for 12 biomass conversion pathways. The water requirement for crop production was attributed only to the grains in the estimates since agricultural residues are produced irrespective of their use for fuel or electricity. Corn stover- and wheat straw-based ethanol production pathways are water efficient, requiring only 0.3 l, whereas biopower production pathways (i.e. direct combustion and bio-oil production) require about 0.8-0.9 l of water per MJ. Wheat- and corn-based ethanol production pathways consume 77 and 108 l of water per MJ, respectively. Utilization of switchgrass for production of ethanol, biopower through the direct combustion, and pyrolysis consume 128, 187 and 229 l of water per MJ, respectively. Biodiesel production from canola seed consumes 124 l of water per MJ. Corn stover- and wheat straw-based conversion pathways are most water efficient.

  11. Measurement of reactive species generated by dielectric barrier discharge in direct contact with water in different atmospheres

    NASA Astrophysics Data System (ADS)

    Kovačević, Vesna V.; Dojčinović, Biljana P.; Jović, Milica; Roglić, Goran M.; Obradović, Bratislav M.; Kuraica, Milorad M.

    2017-04-01

    The formation of hydroxyl radical and long-living chemical species (H2O2, O3, \\text{NO}3- and \\text{NO}2- ) generated in the liquid phase of a water falling film dielectric barrier discharge in dependence on the gas atmosphere (air, nitrogen, oxygen, argon and helium) was studied. The chemical molecular probe dimethyl sulfoxide was employed for quantification of ˙OH, and the influence of hydroxyl radical scavenging on formation of reactive oxygen and nitrogen species was investigated. In addition to liquid analysis, plasma diagnostics was applied to indicate possible reaction pathways of plasma-liquid interaction. The highest ˙OH production rate of 1.19  ×  10-5 mol l-1 s-1 was found when water was treated in oxygen, with a yield of 2.75  ×  10-2 molecules of ˙OH per 100 eV. Formation of hydrogen peroxide in air, nitrogen and argon discharges is determined by recombination reaction of hydroxyl radicals, reaching the highest yield of about 0.7 g kWh-1 when distilled water was treated in argon discharge. Ozone formation was dominant in oxygen and air discharges. Strong acidification along with formation of reactive nitrogen species was detected in water treated in air and nitrogen discharges.

  12. Spectroscopic Observation of Water-Mediated Deformation of the CARBOXYLATE-M2+ (M= Mg, Ca) Contact Ion Pair

    NASA Astrophysics Data System (ADS)

    Kelleher, Patrick J.; DePalma, Joseph W.; Johnson, Mark

    2016-06-01

    The binding of alkaline earth dications to the biologically relevant carboxylate ligand has previously been studied using vibrational sum frequency generation (VSFG) spectroscopy of the air-water interface, infrared multiple photon dissociation (IRMPD) spectroscopy of clusters, and DFT methods. These results suggest the presence of both monodentate and bidentate binding motifs of the M2+ ions to the cayboxyl head groups depending on the extent of solvation. We revisit these systems using vibrational predissociation spectroscopy to measure the gas-phase vibrational spectra of the D2-tagged microhydrated [MgOAc(H2O)n=1-5]+ and [CaOAc(H2O)n=1-6]+ clusters. The spectra show that [MgOAc(H2O)n]+ switches from bidentate to monodentate binding promptly at n = 5, while [CaOAc(H2O)n]+ retains its bidentate attachment such that the sixth water molecule initiates the second solvation shell. The difference in binding behavior between these two divalent metal ions is analyzed in the context of the local acidity of the solvent water molecules and the strength of the metal-carboxylate and metal-water interactions. This cluster study provides insight into the chemical physics underlying the unique and surprising impacts of Mg2+ and Ca2+ on the chemistry mediated by sea spray aerosols. Funding for this work was provided by the NSF's Center for Aerosol Impacts on Climate and the Environment.

  13. Results of experiments related to contact of mine-spoils water with coal, West Decker and Big Sky Mines, southeastern Montana

    USGS Publications Warehouse

    Davis, R.E.; Dodge, K.A.

    1986-01-01

    Batch-mixing experiments using spoils water and coal from the West Decker and Big Sky Mines were conducted to determine possible chemical changes in water moving from coal-mine spoils through a coal aquifer. The spoils water was combined with air-dried and oven-dried chunks of coal and air-dried and oven-dried crushed coal at a 1:1 weight ratio, mixed for 2 hr, and separated after a total contact time of 24 hr. The dissolved-solids concentration in water used in the experiments decreased an average 210 mg/liter (5-10%). Other chemical changes included general decreases in the concentrations of magnesium, potassium, and bicarbonate, and general increases in the concentrations of barium and boron. The magnitude of the changes increased as the surface area of the coal increased. The quantity of extractable cations and exchangeable cations on the post-mixing coal was larger than on the pre-mixing coal. Equilibrium and mass-transfer relations indicate that adsorption reactions or ion-exchange and precipitation reactions, or both, probably are the major reactions responsible for the chemical changes observed in the experiments. (Authors ' abstract)

  14. Factors affecting ground-water quality in Oakland County, Michigan

    USGS Publications Warehouse

    ,

    2004-01-01

    Ground water is water stored in pores within soil and rock beneath the land surface. When these pores are connected so that water can be transmitted to wells or springs, these bodies of soil and rock are termed aquifers, from two Greek words meaning “water” and “to bear.” 

  15. Organic-inorganic interactions at oil-water contacts: quantitative retracing of processes controlling the CO2 occurrence in Norwegian oil reservoirs

    NASA Astrophysics Data System (ADS)

    van Berk, Wolfgang; Schulz, Hans-Martin

    2010-05-01

    Crude oil quality in reservoirs can be modified by degradation processes at oil-water contacts (OWC). Mineral phase assemblages, composition of coexisting pore water, and type and amount of hydrocarbon degradation products (HDP) are controlling factors in complex hydrogeochemical processes in hydrocarbon-bearing siliciclastic reservoirs, which have undergone different degrees of biodegradation. Moreover, the composition of coexisting gas (particularly CO2 partial pressure) results from different pathways of hydrogeochemical equilibration. In a first step we analysed recent and palaeo-OWCs in the Heidrun field. Anaerobic decomposition of oil components at the OWC resulted in the release of methane and carbon dioxide and subsequent dissolution of feldspars (anorthite and adularia) leading to the formation of secondary kaolinite and carbonate phases. Less intensively degraded hydrocarbons co-occur with calcite, whereas strongly degraded hydrocarbons co-occur with solid solution carbonate phase (siderite, magnesite, calcite) enriched in δ13C. To test such processes quantitatively in a second step, CO2 equilibria and mass transfers induced by organic-inorganic interactions have been hydrogeochemically modelled in different semi-generic scenarios with data from the Norwegian continental shelf (acc. Smith & Ehrenberg 1989). The model is based on chemical thermodynamics and includes irreversible reactions representing hydrolytic disproportionation of hydrocarbons according to Seewald's (2006) overall reaction (1a) which is additionally applied in our modelling work in an extended form including acetic acid (1b): (1) R-CH2-CH2-CH3 + 4H2O -> R + 2CO2 + CH4 + 5H2, (2) R-CH2-CH2-CH3 + 4H2O -> R + 1.9CO2 + 0.1CH3COOH + 0.9CH4 + 5H2. Equilibrating mineral assemblages (different feldspar types, quartz, kaolinite, calcite) are based on the observed primary reservoir composition at 72 °C. Modelled equilibration and coupled mass transfer were triggered by the addition and reaction

  16. Water quality: a factor in Arkansas River development

    USGS Publications Warehouse

    Dover, T.B.

    1957-01-01

    One of the first requisites for intelligent planning of the utilization and control of water and for the administration of laws relating to its use, is data on the quantity, quality, and mode of occurence of water supplies. The collections, evaluation, interpretation, and publication of such data constitute the primary function of the Water Resources Division of the United States Geological Survey. Since 1895 the Congress has made appropriations to this agency for investigations of the water resources of the Nation. In 1929 the Congress adopted the policy of dollar-for-dollar cooperation with State and local governmental agencies for water-resources investigations. The Geological Survey's Federal-State cooperative program of quality-of-water investigations in Oklahoma was started in 1944 in cooperation with the Oklahoma Planning and Resources Board. Since July of this year the program has been carried on cooperatively with the newly created Oklahoma Water Resources Board.

  17. Non-contact quantification of laser micro-impulse in water by atomic force microscopy and its application for biomechanics

    NASA Astrophysics Data System (ADS)

    Hosokawa, Yoichiroh

    2011-12-01

    We developed a local force measurement system of a femtosecond laser-induced impulsive force, which is due to shock and stress waves generated by focusing an intense femtosecond laser into water with a highly numerical aperture objective lens. In this system, the force localized in micron-sized region was detected by bending movement of a cantilever of atomic force microscope (AFM). Here we calculated the bending movement of the AFM cantilever when the femtosecond laser is focused in water at the vicinity of the cantilever and the impulsive force is loaded on the cantilever. From the result, a method to estimate the total of the impulsive force at the laser focal point was suggested and applied to estimate intercellular adhesion strength.

  18. Allergic contact dermatitis.

    PubMed

    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.

  19. Impact of Selected Factors on the Occurrence of Contact Dermatitis in Turkeys on Commercial Farms in Germany

    PubMed Central

    Krautwald-Junghanns, Maria-Elisabeth; Bergmann, Shana; Erhard, Michael H.; Fehlhaber, Karsten; Hübel, Jens; Ludewig, Martina; Mitterer-Istyagin, Heike; Ziegler, Nina; Bartels, Thomas

    2013-01-01

    Simple Summary In two extensive field studies in Germany, the influence of husbandry on health and fitness of fattening turkeys was investigated in living animals of various ages as well as carcasses shortly after slaughter. Already in the early rearing phase, contact dermatitis of foot pads was observed as a relevant problem in turkey farming. Litter quality and condition as well as management must be coordinated at all rearing stages of turkeys to prevent the appearance of high litter moisture values in order to minimize the prevalence of foot pad dermatitis. Abstract In a long term research project in Germany the influence of husbandry on the health of fattening turkeys (Study 1) as well as the influence of practiced rearing conditions on the health of turkey poults (Study 2) was examined in 24 farms and at the meat processing plant. In all examined rearing farms, litter samples for the determination of litter moisture were taken. This paper summarizes the results obtained by our working group from 2007 until 2012. The results elucidate the universal problem of foot pad dermatitis (FPD). Nearly 100% of the observed turkeys showed a clinically apparent FPD at the meat processing plant. Furthermore, skin lesions of the breast, especially breast buttons were diagnosed, particularly at the slaughterhouse. FPD was detected in the first week of the rearing phase. Prevalence and degree showed a progressive development up to the age of 22–35 days, whereas 63.3% of the poults had foot pad alterations. As even mild alterations in the foot pad condition can be indicators for suboptimal design of the rearing environment, especially high litter moisture, it is important to focus on the early rearing phase. PMID:26479524

  20. Success Factors for International Postgraduate Students' Adjustment: Exploring the Roles of Intercultural Competence, Language Proficiency, Social Contact and Social Support

    ERIC Educational Resources Information Center

    Young, Tony J.; Sercombe, Peter G.; Sachdev, Itesh; Naeb, Rola; Schartner, Alina

    2013-01-01

    The growth in the number of 'international' students in higher education is a phenomenon of increasing importance to educators, researchers and policymakers worldwide. This multi-methodological study explored factors associated with their adjustment, successful or otherwise. It integrated associations across three domains of enquiry which had…

  1. Success Factors for International Postgraduate Students' Adjustment: Exploring the Roles of Intercultural Competence, Language Proficiency, Social Contact and Social Support

    ERIC Educational Resources Information Center

    Young, Tony J.; Sercombe, Peter G.; Sachdev, Itesh; Naeb, Rola; Schartner, Alina

    2013-01-01

    The growth in the number of 'international' students in higher education is a phenomenon of increasing importance to educators, researchers and policymakers worldwide. This multi-methodological study explored factors associated with their adjustment, successful or otherwise. It integrated associations across three domains of enquiry which had…

  2. Operational water consumption and withdrawal factors for electricity generating technologies: a review of existing literature

    NASA Astrophysics Data System (ADS)

    Macknick, J.; Newmark, R.; Heath, G.; Hallett, K. C.

    2012-12-01

    This report provides estimates of operational water withdrawal and water consumption factors for electricity generating technologies in the United States. Estimates of water factors were collected from published primary literature and were not modified except for unit conversions. The water factors presented may be useful in modeling and policy analyses where reliable power plant level data are not available. Major findings of the report include: water withdrawal and consumption factors vary greatly across and within fuel technologies, and water factors show greater agreement when organized according to cooling technologies as opposed to fuel technologies; a transition to a less carbon-intensive electricity sector could result in either an increase or a decrease in water use, depending on the choice of technologies and cooling systems employed; concentrating solar power technologies and coal facilities with carbon capture and sequestration capabilities have the highest water consumption values when using a recirculating cooling system; and non-thermal renewables, such as photovoltaics and wind, have the lowest water consumption factors. Improved power plant data and further studies into the water requirements of energy technologies in different climatic regions would facilitate greater resolution in analyses of water impacts of future energy and economic scenarios. This report provides the foundation for conducting water use impact assessments of the power sector while also identifying gaps in data that could guide future research.

  3. Tear film proteins deposited on high water content contact lenses identified with two-dimensional gel electrophoresis and mass spectrometry.

    PubMed

    Nielsen, Kim; Vorum, Henrik; Ehlers, Niels; Aagaard, Nicolaj; Hjortdal, Jesper; Honoré, Bent

    2015-11-01

    Tear film proteins adhere to the surface of contact lenses (CLs). While the proteins in the tears have been extensively studied with various proteomic techniques, adhered proteins to CLs are less studied. In this pilot study, we have separated proteins with 2D gel electrophoresis prior to the conventional mass spectrometry (MS) in order to analyse the deposited proteins on hydrogel CLs from myopic patients. pHEMA and PVA hydrogel CLs worn by 3 patients for different time lengths were analysed. After wear, the CLs were frozen at -20°C. Proteins were extracted in lysis buffer, separated on 12% polyacrylamide gels and silver-stained. Protein spots were excised and identified with liquid chromatography - tandem MS. Deposited proteins were extracted with a yield of 26-66 μg and separated by 2D gel electrophoresis. The silver-stained gels showed similar protein patterns independent of the patient, hydrogel type and wear time. Seventy-two spots were analysed with MS, representing at least 12 different tear film proteins or protein fragments. Deposited tear film proteins from a single set of CLs worn for 1 day can successfully be analysed first with 2D gel electrophoresis and subsequently with MS, thus making examination of individual patients possible. The protein composition appeared homogeneous between the test persons which is a necessity for additional comparison analysis. The molecular masses of the identified proteins indicate that protein degradation occurs only as a minor event. Myopic patients were investigated in this pilot study, but the combined techniques can easily be applied to other eye diseases. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  4. Factors Influencing Survival of Legionella pneumophila Serotype 1 in Hot Spring Water and Tap Water

    PubMed Central

    Ohno, Akira; Kato, Naoyuki; Yamada, Koji; Yamaguchi, Keizo

    2003-01-01

    The factors involved in the survival of Legionella pneumophila in the microcosms of both hot spring water and tap water were studied by examining cultivability and metabolic activity. L. pneumophila could survive by maintaining metabolic activity but was noncultivable in all microcosms at 42°C, except for one microcosm with a pH of <2.0. Lower temperatures supported survival without loss of cultivability. The cultivability declined with increasing temperature, although metabolic activity was observed at temperatures of up to 45°C. The optimal range of pH for survival was between 6.0 and 8. The metabolic activity could be maintained for long periods even in microcosms with high concentrations of salt. The cultivability of organisms in the post-exponential phase in a tap water microcosm with a low inoculum size was more rapidly reduced than that of organisms in the exponential phase. In contrast, the loss of cultivability in microcosms of a high inoculum size was significant in the exponential phase. Random(ly) amplified polymorphic DNA analysis of microcosms where cultivability was lost but metabolic activity was retained showed no change compared to cells grown freshly, although an effect on the amplified DNA band pattern by production of stress proteins was expected. Resuscitation by the addition of Acanthamoeba castellanii to the microcosm in which cultivability was completely lost but metabolic activity was maintained was observed only in part of the cell population. Our results suggest that L. pneumophila cell populations can potentially survive as free organisms for long periods by maintaining metabolic activity but temporarily losing cultivability under strict environments and requiring resuscitation by ingestion by amoebas. PMID:12732519

  5. Factors Influencing Water Consumption in Multifamily Housing in Tempe Arizona

    NASA Astrophysics Data System (ADS)

    Wentz, E. A.

    2012-12-01

    Central to the "Smart Growth" movement is that compact development reduces vehicle miles traveled, carbon emissions, and water use. Empirical efforts to evaluate compact development have examined residential densities, but have not distinguished decreasing lot sizes from multifamily apartments as mechanisms for compact development. Efforts to link design features to water use have emphasized single-family at the expense of multifamily housing. This study isolates the determinants of water use in large (>50) unit apartment complexes in the city of Tempe, Arizona. In July 2007, per-bedroom water use increased with pool area, dishwashers, in-unit laundry facilities, and irrigated landscaping. We explain nearly 50% of the variation in water use with these variables. These results inform public policy for reducing water use in multifamily housing structures, suggesting strategies to construct and market "green" apartment units.

  6. Study of the Reactions Controlling the Mobility of Uranium in Ground and Surface Water Systems in Contact with Apatite

    SciTech Connect

    Taffet, M

    2004-04-22

    The objective of this project was to define the mechanisms, equilibria, kinetics, and extent of sorption of aqueous uranium onto hydroxyapatite (Ca{sub 5}(PO{sub 4}){sub 3}(OH)) for a range of pH, ionic strength, aqueous uranium concentration, dissolved carbon/air CO{sub 2}, and mineral surface area. We conducted chemical modeling, batch and flow-through experiments, chemical analysis, x-ray absorption and diffraction measurement, and electron microscopy. Our motivation was the need to immobilize U in water and soil to prevent it's entry into water supplies and ultimately, biological systems. Applying hydroxyapatite to in-situ treatment of uranium-bearing ground water could be an effective, low cost technology. We found that hydroxyapatite quickly, effectively, and reversibly sorbed uranium at a high capacity by inner-sphere complexation over a wide range of conditions. Our results indicate that at aqueous uranium concentrations below 10-20 ppb: (1) equilibrium sorption of uranium to hydroxyapatite occurs in hours, regardless of pH; (2) in ambient and CO{sub 2}-free atmospheres, over 98% of initial uranium is sorbed to hydroxyapatite, (3) in waters in equilibrium with higher air CO{sub 2} concentrations, sorption removed over 97% of aqueous uranium, except above pH 9, where aqueous uranium concentrations were reduced by less than 40%, and (4) at near-neutral pH, bicarbonate alkalinities in excess of 500 slightly retarded sorption of uranium to hydroxyapatite, relative to lower alkalinities. Uranium sorption and precipitation are reversible and are not appreciably affected by ionic strength. The reversibility of these reactions requires that in situ treatment be carefully monitored to avoid breakthrough and de-sorption of uranium unto ground water. At typical surface conditions, sorption is the only mode of uranium sequestration below 20-50 ppb U - above this range, precipitation of uranium phosphate minerals begins to dominate sequestration processes. We verified

  7. The effects of oxygen plasma and humidity on surface roughness, water contact angle and hardness of silicon, silicon dioxide and glass

    NASA Astrophysics Data System (ADS)

    Alam, A. U.; Howlader, M. M. R.; Deen, M. J.

    2014-03-01

    For heterogeneous integration in many More-than-Moore applications, surface preparation is the key step to realizing well-bonded multiple substrates for electronics, photonics, fluidics and/or mechanical components without a degradation in performance. Therefore, it is critical to understand how various processing and environmental conditions affect their surface properties. In this paper, we investigate the effects of oxygen plasma and humidity on some key surface properties such as the water contact angle, roughness and hardness of three materials: silicon (Si), silicon dioxide (SiO2) and glass, and their impact on bondability. The low surface roughness, high surface reactivity and high hydrophilicity of Si, SiO2 and glass at lower activation times can result in better bondability. Although, the surface reactivity of plasma-ambient-humidity-treated Si and SiO2 is considerably reduced, their reduction of roughness and increase of hydrophilicity may enable good bonding at low temperature heating due to augmented hydroxyl groups. The decrease of hardness of Si and SiO2 with increased activation time is attributed to higher surface roughness and the formation of amorphous layers of Si. While contact angle and surface roughness results show a correlation with bondability, the role of hardness on bondability requires further investigation.

  8. Factors affecting alkaline nature of rain water in Agra (India).

    PubMed

    Saxena, A; Sharma, S; Kulshrestha, U C; Srivastava, S S

    1991-01-01

    Rain water was collected and analysed from a reference site, Dayalbagh and Taj Ganj, near the Taj Mahal in Agra. The ionic components Ca, Mg, Na, K, NH(4), Pb, Fe, Zn, SO(4), HCO(3), Cl and F were analysed along with pH, alkalinity and conductance. The average pH of rain water at both sites is 7.05. There is a dominance of alkaline components, particularly Ca. The rain water chemistry shows the importance of calcareous soil-derived materials in controlling the pH of rain water.

  9. [Health risk assessment of heavy metals in drinking water based on field measurement of exposure factors of Chinese people].

    PubMed

    Duan, Xiao-li; Wang, Zong-shuang; Li, Qin; Zhang, Wen-jie; Huang, Nan; Wang, Bei-bei; Zhang, Jin-liang

    2011-05-01

    This study was carried out in Biyang County, located in the junction of Yangtze river and Huaihe river. Drinking water samples of 20 sites in urban and rural areas in this county were collected to measure 14 heavy metals by ICP/MS. About 2 500 subjects with different age and sex were selected to measure exposure factors. Time-activity of drinking water by ingestion and dermal contact of each individual subject during the last three days were kept in dairy in detail by questionnaires. Intake of drinking water from direct and indirect consumption of water and time duration of dermal contact to water in each individual subject were kept in record based on real time measurements. Human health risks were assessed and sensitivity of exposure factors and uncertainty of risks were also analyzed. The results showed that the average drinking water intake rate of male and female are 2276 mL/d, 2265 mL/d in urban adults and 2464 mL/d, 2170 mL/d in rural adults respectively. Body surface area of male and female are 1.806 m2, 1.641 m2 in urban adults and 1.747 m2, 1.617 m2 in rural adults respectively. The contents of 14 heavy metals in this study area are all below the national drinking water standards. Cancer risks from exposure to As are ranged from 2.5 x 10(-6) to 5.2 x 10(-6) through ingestion and 1.1 x 10(-7) to 2.3 x 10(-7) through dermal exposure. Non-cancer risks are ranged from 2.1 x 10(-7) to 1.7 x 10(-6) through ingestion and 1.0 x 10(-8) to 6.0 x 10(-8) through dermal exposure. Non-cancer risks in rural population are 2.1 times to 5.6 times to the risks in urban populations. However all the risks are below the acceptable level. The sensitivity of various exposure factors including drinking water intake rate, dermal exposure time and body surface area are 71.5%. This indicates that exposure factors play a very important role in health risk assessment. Health risks in this research based on real measurement of exposure factors are about 0.94 time to 6.33 times higher

  10. Increase in the water contact angle of composite film surfaces caused by the assembly of hydrophilic nanocellulose fibrils and nanoclay platelets.

    PubMed

    Wu, Chun-Nan; Saito, Tsuguyuki; Yang, Quanling; Fukuzumi, Hayaka; Isogai, Akira

    2014-08-13

    Controlling the assembly modes of different crystalline nanoparticles in composites is important for the expression of specific characteristics of the assembled structures. We report a unique procedure for increasing water contact angles (CAs) of composite film surfaces via the assembly of two different hydrophilic components, nanocellulose fibrils and nanoclay platelets. The nanocellulose fibrils and nanoclay platelets used have ionic groups on their surfaces in high densities (∼1 mmol g(-1)) and have no hydrophobic surface. The increase in the CA of the nanocellulose/nanoclay composite films was thus analyzed on the basis of the air area fractions of their nanostructured surfaces following Cassie's law. The air area fractions were geographically estimated from the atomic force microscopy height profiles of the composite film surfaces. The CAs of the composite film surfaces were found to be well described by Cassie's law. Interestingly, the composite films consisting of two hydrophilic nanoelements with different shapes exhibited CAs larger than those of the individual neat films.

  11. Contact hysteroscopy.

    PubMed

    Baggish, M S; Barbot, J

    1983-06-01

    In 1907 innovations in optics and illumination made by Maximilian Nitze were applied to hysteroscopy by Charles David, who wrote a treatise of hysteroscopy. David improved illumination by placing an electric incandescent bulb at the intrauterine end of his endoscope and also sealed the distal end of the tube with a piece of glass. The history of the contact endoscope that the authors personally used is connected to the invention by Vulmiere (1952) of a revolutionary illumination process in endoscopy--the "cold light" process. The components of cold light consist of a powerful external light source that is transmitted via a special optical guide into the endometrial cavity. The 1st application of his principle (1963) was an optical trochar contained in a metallic sheath. This simple endoscope was perfected, and in 1973 Barbot and Parent, in France, began to use it to examine the uterine cavity. Discussion focuses on methods, instrumentation, method for examination (grasping the instrument, setup, light source, anesthesia, dilatation, technique, and normal endometrium); cervical neoplasia; nonneoplastic lesions of the endometrium (endometrial polyp, submucous myoma, endometrial hyperplasia); intrauterine device localization; neoplastic lesions of the endometrium; precursors (adenocarcinoma); hysteroscopy in pregnancy (embryoscopy, hydatidiform mole, postpartum hemorrhage, incomplete abortion, spontaneous abortion, induced abortions, and amnioscopy); and examinations of children and infants. The contact endoscope must make light contact with the structure to be viewed. The principles of contact endoscopy depend on an interpretation of color, contour, vascular pattern, and a sense of touch. These are computed together and a diagnosis is made on the basis of previously learned clinical pathologic correlations. The contact endoscope is composed of 3 parts: an optical guide; a cylindric chamber that collects and traps ambient light; and a magnifying eyepiece. The phase of

  12. Restoration of the contact surface in FORCE-type centred schemes II: Non-conservative one- and two-layer two-dimensional shallow water equations

    NASA Astrophysics Data System (ADS)

    Canestrelli, Alberto; Toro, Eleuterio F.

    2012-10-01

    Recently, a non-conservative well-balanced FORCE-type scheme has been proposed for solving multidimensional non-conservative equations such as the shallow water equations [4], the two-fluid flow model of Pitman and Le and the two- and three-dimensional Baer-Nunziato equations for compressible multiphase flows [17]. In the present paper the original scheme is first rewritten in a suitable form that allows easy manipulation of numerical fluxes. We then propose a modified scheme that provides a better resolution of contact waves for both one-layer and two-layer shallow water models. The improvement is particularly evident when an additional equation is solved for a passive solute. In this case, the original scheme does not satisfy the C-property for a uniformly distribute tracer, whereas the modified scheme provides a solution that is exact up to machine precision. Moreover, the modified scheme better resolves contact discontinuities, with an accuracy close to the one provided by a fully-upwind non-conservative ROE-type scheme accounting for the complete wave structure. When higher orders are achieved, the difference in accuracy between the various schemes is less pronounced. Moreover, the capability of the two-dimensional scheme to capture steady states is analyzed for both straight and meandering non-flat channels with non-zero friction, and for both one-layer and two-layer equations. Whereas the original first order FORCE scheme is able to correctly reproduce the longitudinal profile in the case of a straight channel even on a coarse mesh, when the channel is strongly meandering a modification of the scheme is necessary, otherwise a very refined mesh and a very high order of accuracy are needed, with a notable increase of computational time.

  13. [Caries and fluorine: role of water factor, problems and solutions].

    PubMed

    Rakhmanin, Iu A; Kir'ianova, L F; Mikhaĭlova, R I; Sevost'ianova, E M

    2001-01-01

    The epidemiological studies of the severity and spread of caries of deciduous and permanent teeth in Moscow schoolchildren (n = > 20,000) aged 7-17 years in relation to the content of fluoride in the drinking water, to the use of fluorine-containing tablets and varnishes have provided evidence for the high efficiency of drinking water fluorination for the primary prevention of caries as compared with other preventive alternatives. Based on sanitary studies, two main lines are now under way in solving the problem connected with low dietary fluoride intake: the introduction of routine water-purifying fluorine generators (based on a new technology of fluorination of limited water volumes for drinking and cooking) and the setting-up of plants manufacturing bottled drinking waters containing the optimum or higher fluorine levels for provision of different population groups, primarily children and pregnant women in particular.

  14. Environmental safety factors estimation in selection of water treatment technologies

    NASA Astrophysics Data System (ADS)

    Gutenyev, V. V.; Azhgirevich, A. I.; Kiryanova, L. F.; Gutenyeva, Ye. N.

    2003-04-01

    A number of southern regions of Russia are traditionally short of drinking water of good quality, especially in summer period or in the places of counter-terror operations. The multifactor analysis covered not only the quality of environmental waters, consumption structure, but the ability of technology to withstand eco terrorism as well. The research works resulted in prioritization of nonchemical combined technologies based on microfiltration and ultraviolet radiation with the use of various bacteriostatics built on ionic complexes of a number of metals, both fixed and mobile. In special operations held on the territory of Chechen Republic to ensure supply of water of guaranteed quality the efforts are focused on organizational activities on provision of traceability of water delivery process at all transportation stages, as well as on application of bacteriostatics in case of long-term water storage.

  15. BioMig--A Method to Evaluate the Potential Release of Compounds from and the Formation of Biofilms on Polymeric Materials in Contact with Drinking Water.

    PubMed

    Wen, Gang; Kötzsch, Stefan; Vital, Marius; Egli, Thomas; Ma, Jun

    2015-10-06

    In contact with water, polymeric materials (plastics) release compounds that can support suspended microbial growth and/or biofilm formation. The different methods presently used in the European Union to test plastics take 7-16 weeks to obtain a result. In industry, this delays material and product development as well as quality testing. Therefore, we developed a method package (BioMig) that allows testing of plastic materials with high reproducibility in 2 weeks for their potential biofilm (or biomass) formation and release of carbonaceous migration products when in contact with water. BioMig consists of (i) an extended migration potential test (seven times for 24 h at 60 °C), based on the European norm EN 12873-1 and the German UBA (Umweltbundesamt) guideline, and (ii) a biomass formation potential (BFP) test (14 days at 30 °C), which is a modified version of the Dutch biofilm production potential test. In the migration potential test, the amount of carbon released into water by the specimen is quantified by monitoring total and assimilable organic carbon over time; furthermore, the modular design of the test also allows one to assess additional parameters such as pathogen growth potential on the migration water or toxic effects on microbial growth. Flow cytometry (FCM)-based total cell counting (TCC) is used to quantify microbial growth in suspension and on surfaces after removal with mild sonication without affecting cell integrity. The BFP test allows one to determine both the planktonic (pBFP) and the sessile (sBFP) cell fractions. The sBFP consists of surface-attached cells after removal (>90% efficiency). Results for four standard test materials (PE-Xa, PE-Xc, EPDM 2%, and EPDM 20%), plus positive (PVC-P) and negative (glass) controls are presented. FCM-based TCC demonstrates that the release of growth-supporting carbon and proliferation of surface-attached cells stops increasing and stabilizes after 14 days of incubation; this allows for faster

  16. Alanine scanning site-directed mutagenesis of the zinc fingers of transcription factor ADR1: residues that contact DNA and that transactivate.

    PubMed Central

    Thukral, S K; Morrison, M L; Young, E T

    1991-01-01

    To identify functionally important amino acids in the two zinc fingers of transcription factor ADR1 [alcohol dehydrogenase (ADH) II synthesis regulator], oligonucleotide-directed mutagenesis was used to substitute alanine for the original amino acid at each position in both fingers. The effects of these mutations on DNA binding and thermal stability of ADR1 in vitro and on activation of ADH2 expression in vivo were measured. The DNA binding activity was remarkably heatstable. Amino acids that are candidates for DNA contact sites were identified in the finger-tip and alpha-helical region of each finger, three in the first finger and two in the second. Unexpectedly, an acidic residue in the first finger was essential for transactivation, but its replacement by alanine had no effect on DNA binding. Substitution at several highly conserved positions did not affect ADR1 functions. The ADR1 zinc fingers appear to make relatively few energetically significant contacts to DNA, perhaps as few as three in the first finger and one in the second. Images PMID:1924382

  17. Risk factors and monitoring for water quality to determine best management practices for splash parks.

    PubMed

    de Man, H; Leenen, E J T M; van Knapen, F; de Roda Husman, A M

    2014-09-01

    Splash parks have been associated with infectious disease outbreaks as a result of exposure to poor water quality. To be able to protect public health, risk factors were identified that determine poor water quality. Samples were taken at seven splash parks where operators were willing to participate in the study. Higher concentrations of Escherichia coli were measured in water of splash parks filled with rainwater or surface water as compared with sites filled with tap water, independent of routine inspection intervals and employed disinfection. Management practices to prevent fecal contamination and guarantee maintaining good water quality at splash parks should include selection of source water of acceptable quality.

  18. A procedure for calculating the swelling of water level and protective means to prevent it from entering into the turbine flow path with the back flow of steam from direct-contact heaters

    NASA Astrophysics Data System (ADS)

    Sukhorukov, Yu. G.; Ermolov, V. F.; Trifonov, N. N.

    2008-02-01

    A procedure is proposed for calculating the swelling of the level of water on the saturation line when an abrupt drop of pressure occurs. A calculated study of the swelling of water level is carried out for different designs of direct-contact heaters. A comparison between the calculated and experimental data is given. The procedure can be used for calculating the swelling of water level in the apparatuses of turbine units at thermal and nuclear power stations and at boiler houses.

  19. Irrigation water productivity is more influenced by agronomic practice factors than by climatic factors in Hexi Corridor, Northwest China

    PubMed Central

    Li, Xiaolin; Zhang, Xiaotao; Niu, Jun; Tong, Ling; Kang, Shaozhong; Du, Taisheng; Li, Sien; Ding, Risheng

    2016-01-01

    Quantifying the influence of driving factors on irrigation water productivity (IWP) is vital for efficient agricultural water use. This study analyzed contributions of agronomic practice and climatic factors to the changes of IWP, based on the data from 1981 to 2012 in Hexi Corridor, Northwest China. Cobb-Douglas production functions were developed by the partial least squares method and contribution rates of the driving factors were calculated. Results showed that IWP and its driving factors increased during the study period, with different changing patterns. IWP was significantly correlated with the agronomic practice factors, daily mean temperature and solar radiation of the crop growing period. The agronomic practice factors including irrigation, fertilization, agricultural film, and agricultural pesticide contributed 20.6%, 32.8%, 42.3% and 11.1% respectively to the increase of IWP; and the contribution rates of the climatic factors, i.e. daily mean temperature and solar radiation, are −0.9% and 0.9%. And the contributions of these factors changed in different sub-periods. It is concluded that agronomic practice factors influenced IWP much more than climatic factors. The improvement of IWP should rely on advanced water-saving technology and application of optimum (need-based) fertilizer, agricultural film and pesticide, ensuring efficient use of agronomic inputs in the study area. PMID:27905483

  20. Irrigation water productivity is more influenced by agronomic practice factors than by climatic factors in Hexi Corridor, Northwest China

    NASA Astrophysics Data System (ADS)

    Li, Xiaolin; Zhang, Xiaotao; Niu, Jun; Tong, Ling; Kang, Shaozhong; Du, Taisheng; Li, Sien; Ding, Risheng

    2016-12-01

    Quantifying the influence of driving factors on irrigation water productivity (IWP) is vital for efficient agricultural water use. This study analyzed contributions of agronomic practice and climatic factors to the changes of IWP, based on the data from 1981 to 2012 in Hexi Corridor, Northwest China. Cobb-Douglas production functions were developed by the partial least squares method and contribution rates of the driving factors were calculated. Results showed that IWP and its driving factors increased during the study period, with different changing patterns. IWP was significantly correlated with the agronomic practice factors, daily mean temperature and solar radiation of the crop growing period. The agronomic practice factors including irrigation, fertilization, agricultural film, and agricultural pesticide contributed 20.6%, 32.8%, 42.3% and 11.1% respectively to the increase of IWP; and the contribution rates of the climatic factors, i.e. daily mean temperature and solar radiation, are -0.9% and 0.9%. And the contributions of these factors changed in different sub-periods. It is concluded that agronomic practice factors influenced IWP much more than climatic factors. The improvement of IWP should rely on advanced water-saving technology and application of optimum (need-based) fertilizer, agricultural film and pesticide, ensuring efficient use of agronomic inputs in the study area.

  1. Irrigation water productivity is more influenced by agronomic practice factors than by climatic factors in Hexi Corridor, Northwest China.

    PubMed

    Li, Xiaolin; Zhang, Xiaotao; Niu, Jun; Tong, Ling; Kang, Shaozhong; Du, Taisheng; Li, Sien; Ding, Risheng

    2016-12-01

    Quantifying the influence of driving factors on irrigation water productivity (IWP) is vital for efficient agricultural water use. This study analyzed contributions of agronomic practice and climatic factors to the changes of IWP, based on the data from 1981 to 2012 in Hexi Corridor, Northwest China. Cobb-Douglas production functions were developed by the partial least squares method and contribution rates of the driving factors were calculated. Results showed that IWP and its driving factors increased during the study period, with different changing patterns. IWP was significantly correlated with the agronomic practice factors, daily mean temperature and solar radiation of the crop growing period. The agronomic practice factors including irrigation, fertilization, agricultural film, and agricultural pesticide contributed 20.6%, 32.8%, 42.3% and 11.1% respectively to the increase of IWP; and the contribution rates of the climatic factors, i.e. daily mean temperature and solar radiation, are -0.9% and 0.9%. And the contributions of these factors changed in different sub-periods. It is concluded that agronomic practice factors influenced IWP much more than climatic factors. The improvement of IWP should rely on advanced water-saving technology and application of optimum (need-based) fertilizer, agricultural film and pesticide, ensuring efficient use of agronomic inputs in the study area.

  2. Factors controlling tungsten concentrations in ground water, Carson Desert, Nevada

    USGS Publications Warehouse

    Seiler, R.L.; Stollenwerk, K.G.; Garbarino, J.R.

    2005-01-01

    An investigation of a childhood leukemia cluster by US Centers for Disease Control and Prevention revealed that residents of the Carson Desert, Nevada, are exposed to high levels of W and this prompted an investigation of W in aquifers used as drinking water sources. Tungsten concentrations in 100 ground water samples from all aquifers used as drinking water sources in the area ranged from 0.27 to 742 ??g/l. Ground water in which W concentrations exceed 50 ??g/l principally occurs SE of Fallon in a geothermal area. The principal sources of W in ground water are natural and include erosion of W-bearing mineral deposits in the Carson River watershed upstream of Fallon, and, possibly, upwelling geothermal waters. Ground water in the Fallon area is strongly reducing and reductive dissolution of Fe and Mn oxyhydroxides may be releasing W; however, direct evidence that the metal oxides contain W is not available. Although W and Cl concentrations in the Carson River, a lake, and water from many wells, appear to be controlled by evaporative concentration, evaporation alone cannot explain the elevated W concentrations found in water from some of the wells. Concentrations of W exceeding 50 ??g/l are exclusively associated with Na-HCO3 and Na-Cl water types and pH > 8.0; in these waters, geochemical modeling indicates that W exhibits <10% adsorption. Tungsten concentrations are strongly and positively correlated with As, B, F, and P, indicating either common sources or common processes controlling their concentrations. Geochemical modeling indicates W concentrations are consistent with pH-controlled adsorption of W. The geochemical model PHREEQC was used to calculate IAP values, which were compared with published Ksp values for primary W minerals. FeWO4, MnWO4, Na2WO4, and MgWO4 were undersaturated and CaWO4 and SrWO 4 were approaching saturation. These conclusions are tentative because of uncertainty in the thermodynamic data. The similar behavior of As and W observed in

  3. Updated Solid Water trade mark sign to water conversion factors for {sup 125}I and {sup 103}Pd brachytherapy sources

    SciTech Connect

    Meigooni, Ali S.; Awan, Shahid B.; Thompson, Nathan S.; Dini, Sharifeh A.

    2006-11-15

    Dosimetric characteristics of brachytherapy sources are normally determined in water using a Monte Carlo simulation technique and in water equivalent phantom material using both experimental and Monte Carlo simulation techniques. The consensuses of these results are then calculated for clinical applications by converting experimental data obtained in water equivalent material to water using a conversion factor. These conversion factors are normally determined as a ratio of the Monte Carlo-simulated dose rate constant in liquid water to the dose rate constant in a water-equivalent phantom material. However, it has been noted that conversion factors utilized by some investigators have been derived using incorrect phantom material composition and incorrect cross-sectional data information. The impact of errors associated with the cross-sectional data and chemical composition of the phantom material used in dosimetric evaluation of brachytherapy sources has been investigated in this project. Results of these investigations have shown that the use of Solid Water trade mark sign with 1.7% calcium content, as compared to the 2.3% value stated by the manufacturer, may lead to 5% and 9% differences in conversion factors for {sup 125}I and {sup 103}Pd, respectively.

  4. Smear positive pulmonary tuberculosis and associated risk factors among tuberculosis suspects attending spiritual holy water sites in Northwest Ethiopia.

    PubMed

    Derseh, Dejene; Moges, Feleke; Tessema, Belay

    2017-01-26

    Tuberculosis (TB) remains one of the world's deadliest communicable diseases. In Ethiopia, tuberculosis patients have different pattern of health care seeking behavior. They usually adopt other approaches like traditional healers and spiritual holy water sites before consulting public health facilities. This study was aimed to assess the prevalence of smear positive pulmonary tuberculosis and associated risk factors among tuberculosis suspects attending spiritual holy water sites. A cross-sectional study was conducted from February 01, 2015 to March 30, 2015 in seven selected holy water sites in Northwest Ethiopia. During the study period, a total of 1384 adult holy water users were screened for PTB symptoms. A total of 382 pulmonary tuberculosis suspects participated in the study. Socio-demographic data were collected using a semi-structured questionnaire. Spot-morning-spot sputum specimens were collected and examined for acid fast bacilli using Auramine O fluorescence staining technique. Smear positive sputum samples were tested by GeneXpert MTB/RIF assay for rifampicin resistance. Descriptive statistics, binary and multivariate logistic regression analysis were employed using SPSS-16 software. The prevalence of smear positive pulmonary tuberculosis was 2.9% with point prevalence of 795/100, 000 holy water users. History of contact with tuberculosis patient (AOR = 9.174, 95% C.I = 2.195-38.34) and the number of family members > 5 per household (AOR = 9.258, 95% C.I = 1.14-74.97) were significantly associated with smear positive pulmonary tuberculosis. Rifampicin resistance was not detected from all smear positives by GeneXpert MTB/RIF assay. The prevalence of smear positive pulmonary tuberculosis in spiritual holy water sites was 7.4 fold higher than the general population. History of contact with active tuberculosis patients and increased family size were significantly associated with smear positive pulmonary TB. The national tuberculosis

  5. THE INCREASING NEED FOR SURVEILLANCE: WATER SOURCES AND ENVIRONMENTAL FACTORS

    EPA Science Inventory

    The outbreaks of giardiosis in the 1980's and the outbreak of cryptosporidiosis in Milwaukee, have demonstrated the susceptibility of public water supplies to contamination with protozoan parasites. Many protozoan parasites are resistant to the levels of residual disinfectant re...

  6. THE INCREASING NEED FOR SURVEILLANCE: WATER SOURCES AND ENVIRONMENTAL FACTORS

    EPA Science Inventory

    The outbreaks of giardiosis in the 1980's and the outbreak of cryptosporidiosis in Milwaukee, have demonstrated the susceptibility of public water supplies to contamination with protozoan parasites. Many protozoan parasites are resistant to the levels of residual disinfectant re...

  7. Determination of the partition coefficient for yeast invertase between microwater droplets in air in contact with liquid water

    SciTech Connect

    Kokitkar, P.B.; Tanner, R.D.

    1991-12-31

    Previously, Baker`s yeast was grown on a semisolid substrate (homogenized whole potatoes) in an air-fluidized bioreactor. During the batch bioprocess, certain proteins were trapped by sparging the effluent air stream into a water chamber. Surprisingly, the proteins carried over were specific ones and not the most abundant ones available in the process mixture. Simple experiments were performed to determine equilibrium data and to estimate the equilibrium constant K{sub eq}, for a single enzyme between a condensed phase and a gas phase containing entrained liquid droplets as is observed in the air-fluidized-bed-bioreactor system that has been previously described. The purpose of this experimental study is to test whether the estimated value for K{sub eq} derived from a postulated model, is, in fact, a directly measurable quantity. If the measured value of K{sub eq} is close to that inferred for the postulated model, then the validity of the model for describing the fluidized bed protein recovery process would be greatly strengthened.

  8. The Effectiveness of Injury Prevention Programs to Modify Risk Factors for Non-Contact Anterior Cruciate Ligament and Hamstring Injuries in Uninjured Team Sports Athletes: A Systematic Review.

    PubMed

    Monajati, Alireza; Larumbe-Zabala, Eneko; Goss-Sampson, Mark; Naclerio, Fernando

    2016-01-01

    Hamstring strain and anterior cruciate ligament injuries are, respectively, the most prevalent and serious non-contact occurring injuries in team sports. Specific biomechanical and neuromuscular variables have been used to estimate the risk of incurring a non-contact injury in athletes. The aim of this study was to systematically review the evidences for the effectiveness of injury prevention protocols to modify biomechanical and neuromuscular anterior cruciate and/or hamstring injuries associated risk factors in uninjured team sport athletes. PubMed, Science Direct, Web of Science, Cochrane Libraries, U.S. National Institutes of Health clinicaltrials.gov, Sport Discuss and Google Scholar databases were searched for relevant journal articles published until March 2015. A manual review of relevant articles, authors, and journals, including bibliographies was performed from identified articles. Nineteen studies were included in this review. Four assessment categories: i) landing, ii) side cutting, iii) stop-jump, and iv) muscle strength outcomes, were used to analyze the effectiveness of the preventive protocols. Eight studies using multifaceted interventions supported by video and/or technical feedback showed improvement in landing and/or stop-jump biomechanics, while no effects were observed on side-cutting maneuver. Additionally, multifaceted programs including hamstring eccentric exercises increased hamstring strength, hamstring to quadriceps functional ratio and/or promoted a shift of optimal knee flexion peak torque toward a more open angle position. Multifaceted programs, supported by proper video and/or technical feedback, including eccentric hamstring exercises would positively modify the biomechanical and or neuromuscular anterior cruciate and/or hamstring injury risk factors.

  9. The Effectiveness of Injury Prevention Programs to Modify Risk Factors for Non-Contact Anterior Cruciate Ligament and Hamstring Injuries in Uninjured Team Sports Athletes: A Systematic Review

    PubMed Central

    Monajati, Alireza; Larumbe-Zabala, Eneko; Goss-Sampson, Mark; Naclerio, Fernando

    2016-01-01

    Background Hamstring strain and anterior cruciate ligament injuries are, respectively, the most prevalent and serious non-contact occurring injuries in team sports. Specific biomechanical and neuromuscular variables have been used to estimate the risk of incurring a non-contact injury in athletes. Objective The aim of this study was to systematically review the evidences for the effectiveness of injury prevention protocols to modify biomechanical and neuromuscular anterior cruciate and/or hamstring injuries associated risk factors in uninjured team sport athletes. Data Sources PubMed, Science Direct, Web of Science, Cochrane Libraries, U.S. National Institutes of Health clinicaltrials.gov, Sport Discuss and Google Scholar databases were searched for relevant journal articles published until March 2015. A manual review of relevant articles, authors, and journals, including bibliographies was performed from identified articles. Main Results Nineteen studies were included in this review. Four assessment categories: i) landing, ii) side cutting, iii) stop-jump, and iv) muscle strength outcomes, were used to analyze the effectiveness of the preventive protocols. Eight studies using multifaceted interventions supported by video and/or technical feedback showed improvement in landing and/or stop-jump biomechanics, while no effects were observed on side-cutting maneuver. Additionally, multifaceted programs including hamstring eccentric exercises increased hamstring strength, hamstring to quadriceps functional ratio and/or promoted a shift of optimal knee flexion peak torque toward a more open angle position. Conclusions Multifaceted programs, supported by proper video and/or technical feedback, including eccentric hamstring exercises would positively modify the biomechanical and or neuromuscular anterior cruciate and/or hamstring injury risk factors. PMID:27171282

  10. Factors Associated with Differences between Conventional Contact Tracing and Molecular Epidemiology in Study of Tuberculosis Transmission and Analysis in the City of Barcelona, Spain ▿

    PubMed Central

    Borrell, Sònia; Español, Montserrat; Orcau, Àngels; Tudó, Griselda; March, Francesca; Caylà, Joan A.; Jansà, Josep Maria; Alcaide, Fernando; Martín-Casabona, Núria; Salvadó, Margarita; Martínez, José Antonio; Vidal, Rafael; Sánchez, Francesca; Altet, Neus; Coll, Pere; González-Martín, Juliàn

    2009-01-01

    The aim of this study was to analyze the factors associated with conventional contact tracing (CCT) and molecular epidemiology (ME) methods in assessing tuberculosis (TB) transmission, comparing the populations studied and the epidemiological links established by both methods. Data were obtained from TB case and CCT registries, and ME was performed using IS6110-based restriction fragment length polymorphism (RFLP) analysis and mycobacterial interspersed repetitive unit 12 (MIRU12) typing as a secondary typing method. During two years (2003 and 2004), 892 cases of TB were reported, of which 687 (77%) were confirmed by culture. RFLP analysis was performed with 463 (67.4%) of the 687 isolated strains, and MIRU12 types in 75 strains were evaluated; 280 strains (60.5%) had a unique RFLP pattern, and 183 (39.5%) shared patterns, grouping into 65 clusters. CCT of 613 (68.7%) of 892 cases detected 44 clusters involving 101 patients. The results of both CCT and ME methods yielded 96 clusters involving 255 patients. The household link was the one most frequently identified by CCT (corresponding to 80.7% of the cases clustered by this method), whereas nonhousehold and unknown links were associated with 94.1% of the strains clustered by ME. When both methods were used in 351 cases (39.3%), they showed the same results in 214 cases (61%). Of the remainder, 106 (30.2%) were clustered only by ME, 19 (5.5%) were clustered only by CCT, and 12 (3.4%) were clustered by both methods but into different clusters. Patients with factors potentially associated with social problems were less frequently studied by CCT (P = 0.002), whereas patients of <15 years of age, most with negative cultures, were less frequently studied by ME (P = 0.005). Significant differences in the populations studied by ME versus CCT were observed, possibly explaining the scarce correlation found between the results of these methods. Moreover, ME allowed the detection of nonhousehold contact relationships, whereas

  11. Chemical analysis and potential endocrine activities of aluminium coatings intended to be in contact with cosmetic water.

    PubMed

    Bou-Maroun, Elias; Dahbi, Laurence; Gomez-Berrada, Marie-Pierre; Pierre, Philippine; Rakotomalala, Sandrine; Ferret, Pierre-Jacques; Chagnon, Marie-Christine

    2017-10-25

    The objective of the work was to check the presence of Non-Intended Added Substances (NIAS) with hormonal activities in aluminium coatings extracts coded: AA, BBF, MC and RR, furnished by four different suppliers. Water samples were prepared at room temperature or at 40°C for three months to verify the storage effect on the coatings. Solid phase extraction was used to concentrate and to extract coating substances. Hormonal activities were checked in vitro using reporter gene bioassays. Except BBF, all extracts induced a weak but significant estrogenic agonist activity in the human cell line. Using an estrogenic antagonist (ICI-182, 780), the answer was demonstrated specific in the bioassay. RR was the only extract to induce a concentration dependent anti-androgenic response in the MDA-KB2 cell line. Analysis performed using GC-MS and HPLC-MS detected 12 substances in most of the extracts. 8 NIAS were present. Among them, 4 were identified with certainty: HMBT, BGA, DCU and BPA. Estrogenic potency was BPA>DCU>BGA>HMBT. HMBT was also anti-androgenic at high concentration. Combining chemical analysis and bioassays data, we demonstrated that in the RR and the RR40 extracts, the observed estrogenic response was mainly due to BPA, the anti-androgenic activity of RR could be due to a synergism between HMBT and BPA. For MC and AA, estrogenic responses appear to be due to the presence of DCU. Except BBF, storage conditions tended to increase estrogenic activities in all extracts. However, in term of risk assessment, activities observed were negligible. This work demonstrated that sensitive bioassays are pertinent tools in complement to chemical analysis to monitor and check the presence of NIAS with hormonal activity in coating extracts. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Association study between growth differentiation factor 5 polymorphism and non-contact anterior cruciate ligament rupture in Chinese Han population

    PubMed Central

    Chen, Biao; Li, Bin; Qi, Yong-Jian; Tie, Kai; Chen, Liao-Bin

    2015-01-01

    Background: Anterior cruciate ligament (ACL) rupture is the most common ligamentous injury for active adolescents and young adults each year. However, the precise etiologies of ACL injury are not fully understood. The present study was to investigate +104T/C polymorphism of growth differentiation factor 5 (GDF5) gene in patients with ACL rupture, and evaluate the effects of polymorphism on GDF5 mRNA levels in ligament of patients with ACL rupture in central China. Methods: A total of 286 Chinese patients with ACL rupture and 500healthy controls were enrolled in this study. The +104T/C polymorphism in GDF5 gene were genotyped by DNA sequencing. GDF5 mRNA expressions levels in ligament were determined by quantitative PCR. Results: The frequency of the TT genotype tended to be higher in ACL rupture group than in control group (62.6% vs. 48.0%, P< 0.001, OR = 1.81, 95% CI: 1.35-2.44). T allele of the GDF5 +104T/C polymorphism was more common in ACL rupture group than in control group (P< 0.001). Patients carrying TT genotype expressed lower levels of GDF5 mRNA than C carriers (P = 0.005) among ACL rupture. Conclusion: Our study indicated that GDF5 +104T/C polymorphism was associated with ACL rupture patients in central China. This is likely from decreased expressions of GDF5 mRNA. Further studies are necessary to explore the functional implication of the GDF5 +104T/C polymorphism in Chinese ACL rupture patients. PMID:26885231

  13. Association study between growth differentiation factor 5 polymorphism and non-contact anterior cruciate ligament rupture in Chinese Han population.

    PubMed

    Chen, Biao; Li, Bin; Qi, Yong-Jian; Tie, Kai; Chen, Liao-Bin

    2015-01-01

    Anterior cruciate ligament (ACL) rupture is the most common ligamentous injury for active adolescents and young adults each year. However, the precise etiologies of ACL injury are not fully understood. The present study was to investigate +104T/C polymorphism of growth differentiation factor 5 (GDF5) gene in patients with ACL rupture, and evaluate the effects of polymorphism on GDF5 mRNA levels in ligament of patients with ACL rupture in central China. A total of 286 Chinese patients with ACL rupture and 500healthy controls were enrolled in this study. The +104T/C polymorphism in GDF5 gene were genotyped by DNA sequencing. GDF5 mRNA expressions levels in ligament were determined by quantitative PCR. The frequency of the TT genotype tended to be higher in ACL rupture group than in control group (62.6% vs. 48.0%, P< 0.001, OR = 1.81, 95% CI: 1.35-2.44). T allele of the GDF5 +104T/C polymorphism was more common in ACL rupture group than in control group (P< 0.001). Patients carrying TT genotype expressed lower levels of GDF5 mRNA than C carriers (P = 0.005) among ACL rupture. Our study indicated that GDF5 +104T/C polymorphism was associated with ACL rupture patients in central China. This is likely from decreased expressions of GDF5 mRNA. Further studies are necessary to explore the functional implication of the GDF5 +104T/C polymorphism in Chinese ACL rupture patients.

  14. Pesticides in surface waters: distribution, trends, and governing factors

    USGS Publications Warehouse

    Larson, Steven J.; Capel, Paul D.; Majewski, Michael

    1997-01-01

    Pesticde use in agriculture and non-agriculture settings has increased dramatically over the last several decades. Concern about adverse effects on the environment and human health has spurred an enormous amount of research into their environmental behavior and fate. Pesticides in Surface Waters presents a comprehensive summary of this research. This book evaluates published studies that focus on measuring pesticide concentration. The studies chosen include peer reviewed scientific literature, government reports, laboratory studies, and those using microcosms and artificial streams and ponds. The authors used this information to develop their overview of pesticide contamination of surface waters. The exhaustive compilation of data along with the fundamental science make this book essential for those involved in pesticide use, environmental protection, water quality, and human or ecological risk assessment. Pesticides in Surface Waters covers the results of actual studies, sources of pesticides to surface water, fate and transport, and environmental significance. Hundreds of data-packed tables, maps, charts, and drawings illustrate the key points, making research and application easy and cost effective.

  15. Prioritized Contact Transport Stream

    NASA Technical Reports Server (NTRS)

    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.

  16. Types of Contact Lenses

    MedlinePlus

    ... Consumer Devices Consumer Products Contact Lenses Types of Contact Lenses Share Tweet Linkedin Pin it More sharing ... Orthokeratology (Ortho-K) Decorative (Plano) Contact Lenses Soft Contact Lenses Soft contact lenses are made of soft, ...

  17. Evolutions in Water Withdrawal and Consumption Factors for Thermoelectric Power Plants in the United States

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Bielicki, J. M.

    2016-12-01

    Accurate estimation of the water withdrawal and consumption rates by thermoelectric power plants is important for water resources management, planning of new electricity generation capacity additions, and understanding potential water stress on agricultural systems. But estimates of water demand by power plants are limited by the availability of temporally resolved and high quality data and are influenced by numerous aspects of the climate, cooling technology, and energy technology. In 2010, the U.S. thermoelectric power sector accounted for about 45% of the total water withdrawal—the largest end-use sector for water withdrawal in the country—but withdrawal and consumption rates are evolving with the popularity of recirculating cooling systems and fuel switching from coal to natural gas. We used data from the U.S. Energy Information Administration to derive monthly water withdrawal and consumption factors for thermoelectric power plants across the United States from 2010 to 2014 and combined that data with information on power plant design, location, and cooling systems from various sources and previous annual datasets. We developed and applied a model that relates the water use factors to cooling system designs, intake water sources, power generation technologies, boiler efficiencies, and weather conditions. We present our analysis of the factors that influence the inter-power plant, seasonal, and inter-annual variability in water-use factors and provide lessons for electricity capacity planning and regional water availability for other uses, including agriculture.

  18. The wetting of steel, DLC coatings, ceramics and polymers with oils and water: The importance and correlations of surface energy, surface tension, contact angle and spreading

    NASA Astrophysics Data System (ADS)

    Kalin, M.; Polajnar, M.

    2014-02-01

    The importance of wetting is becoming increasingly obvious and its control is inevitable in many engineering applications, including tribology and interface nanotechnology. However, the relations between the key parameters affecting surface-liquid wetting behaviour under realistic conditions are not very well understood, especially for typical engineering materials and lubricants (oils), often leading to exceptions and contradictions, which impede their use in engineering models and theories, and so the possible optimisation of the interfaces of engineering systems. In this paper we present the correlations between the contact angle, the spreading, the surface tension and the surface energy of fourteen frequently used engineering materials belonging to four different classes of materials (steel, DLC coatings, ceramics, and polymers) wetted with four different liquids: three oils (a non-polar synthetic oil of two different viscosities and a polar natural-based oil) and water. The results represent systematically and consistently obtained data about the wetting-relevant parameters of the selected materials and lubricants and numerous correlations between them. However, the most striking result suggests that the spreading parameter correlates very linearly with the surface energy for all the materials and liquids studied, in both the adhesion-wetting and spreading-wetting regimes. The experimentally determined spreading vs. surface energy correlation functions that appear generally valid for a broad range of properties of the materials and oils can thus be applied as an engineering tool to tailor and design the required/desired wetting performance and nature of the solid-liquid interfaces. The spreading parameter SP - in contrast to the contact angle - was found to be a reliable and relevant parameter for describing the wetting of oils with selected engineering materials.

  19. Contact activation of blood-plasma coagulation

    NASA Astrophysics Data System (ADS)

    Golas, Avantika

    Surface engineering of biomaterials with improved hemocompatibility is an imperative, given the widespread global need for cardiovascular devices. Research summarized in this dissertation focuses on contact activation of FXII in buffer and blood plasma frequently referred to as autoactivation. The extant theory of contact activation imparts FXII autoactivation ability to negatively charged, hydrophilic surfaces. According to this theory, contact activation of plasma involves assembly of proteins comprising an "activation complex" on activating surfaces mediated by specific chemical interactions between complex proteins and the surface. This work has made key discoveries that significantly improve our core understanding of contact activation and unravel the existing paradigm of plasma coagulation. It is shown herein that contact activation of blood factor XII (FXII, Hageman factor) in neat-buffer solution exhibits a parabolic profile when scaled as a function of silanized-glass-particle activator surface energy (measured as advancing water adhesion tension t°a=g° Iv costheta in dyne/cm, where g°Iv is water interfacial tension in dyne/cm and theta is the advancing contact angle). Nearly equal activation is observed at the extremes of activator water-wetting properties --36 < t°a < 72 dyne/cm (O° ≤ theta < 120°), falling sharply through a broad minimum within the 20 < t°a < 40 dyne/cm (55° < theta < 75°). Furthermore, contact activation of FXII in buffer solution produces an ensemble of protein fragments exhibiting either procoagulant properties in plasma (proteolysis of blood factor XI or prekallikrein), amidolytic properties (cleavage of s-2302 chromogen), or the ability to suppress autoactivation through currently unknown biochemistry. The relative proportions of these fragments depend on activator surface chemistry/energy. We have also discovered that contact activation is moderated by adsorption of plasma proteins unrelated to coagulation through an

  20. STREAM NETWORK EXPANSION: A RIPARIAN WATER QUALITY FACTOR

    EPA Science Inventory

    Little is known about how active stream network expansion during rainstorms influences the ability of riparian buffers to improve water quality. We used aerial photographs to quantify stream network expansion during the wet winter season in five agricultural watersheds in western...

  1. Water consumption patterns and factors contributing to water consumption in arsenic affected population of rural West Bengal, India.

    PubMed

    Hossain, M Amir; Rahman, Mohammad Mahmudur; Murrill, Matthew; Das, Bhaskar; Roy, Bimol; Dey, Shankar; Maity, Debasish; Chakraborti, Dipankar

    2013-10-01

    A direct water intake study was conducted for one year, involving 423 individuals from three arsenic (As) affected villages of West Bengal, India. Average direct water intake per person and per unit body weight was found to be 3.12±1.17 L/day and 78.07±47.08 mL/kg/day (± SD), respectively. Average direct water intakes for adult males, adult females and children (age <15 years) were 3.95, 3.03 and 2.14 L/day, respectively. Significant sex differentials were observed between ages 16-55 years. For all participants, a sharp increase in water intake up to 15 years of age was observed followed by a plateau at a higher intake level. Significant monthly, seasonal, regional, and occupational variability was also observed. Another study involving 413 subjects determined the amount of indirect water intake. Average indirect water intake per person was 1.80±0.64 L/day; for adult males, adult females and children, intake was 2.15, 1.81, and 1.10 L/day, respectively. Average total (direct + indirect) water intake was 4.92 L/person/day; for adult males, adult females and children, total intake was 6.10, 4.84, and 3.24 L/person/day, respectively. The overall contribution of indirect water intake to total water consumption was 36.6% for all participants. This study additionally elucidated several factors that contribute to variable water intake, which can lead to better risk characterization of subpopulations and water contaminant ingestion. The study reveals that the water intake rates in the three studied populations in West Bengal are greater than the assumed water intake rates utilized by the World Health Organization (WHO) in the establishment of drinking water quality guidelines; therefore, these assumed intake values may be inappropriate for the study population as well as similar ones.

  2. Water consumption patterns and factors contributing to water consumption in arsenic affected population of rural West Bengal, India

    PubMed Central

    Hossain, M. Amir; Rahman, Mohammad Mahmudur; Murrill, Matthew; Das, Bhaskar; Roy, Bimol; Dey, Shankar; Maity, Debasish; Chakraborti, Dipankar

    2014-01-01

    A direct water intake study was conducted for one year, involving 423 individuals from arsenic (As) affected villages of West-Bengal, India. Average direct water intake per person was found to be 3.12±1.17 L/day and 78.07±47.08 mL/kg/day (±SD). Average direct water intakes for adult males, adult females and children (age <15 years) were 3.95, 3.03 and 2.14 L/day, respectively. Significant sex differentials were observed between ages 16–55 years. For all participants, a sharp increase in water intake up to age 15 years was observed followed by a plateau at a higher intake level. Significant monthly, seasonal, regional, and occupational variability was also observed. Another study involving 413 subjects determined the amount of indirect water intake. Average indirect water intake per person was 1.80±0.64 L/day; for adult males, females and children, intake was 2.15, 1.81, and 1.10 L/day, respectively. Average total (direct + indirect) water intake was 4.92 L/person/day; for adult males, females and children total intake was 6.10, 4.84, and 3.24 L/person/day, respectively. The overall contribution of indirect water intake to total water consumption is 36.6% for all participants. This study additionally elucidated several factors that contribute to variable water intake, which can lead to better risk characterization of subpopulations and water contaminant ingestion. The study reveals that the water intake rates in the three studied populations in West Bengal are greater than the assumed water intake rates utilized by the World Health Organization (WHO) in the establishment of drinking water quality guidelines; therefore, these assumed intake values may be inappropriate for the study population as well as similar ones. PMID:22858413

  3. Virtual water trade patterns in relation to environmental and socioeconomic factors: a case study for Tunisia

    NASA Astrophysics Data System (ADS)

    Chouchane, Hatem; Krol, Maarten; Hoekstra, Arjen

    2016-04-01

    Water scarcity is among the main problems faced by many societies. Growing water demands put increasing pressure on local water resources, especially in water-short countries. Virtual water trade can play a key role in filling the gap between local demands and supply. This study aims to analyze the changes in virtual water trade of Tunisia in relation to environmental and socio-economic factors such as GDP, irrigated land, precipitation, population and water scarcity. The water footprint is estimated using Aquacrop for six crops over the period 1981-2010 at daily basis and a spatial resolution of 5 by 5 arc minutes. Virtual water trade is quantified at yearly basis. Regression models are used to investigate changes in virtual water trade in relation to various environmental and socio-economic factors. The explaining variables are selected in order to help understanding the trend and the inter-annual variability of the net virtual water import; GDP, population and irrigated land are hypothesized to explain the trend, and precipitation and water scarcity to explain variability. The selected crops are divided into three baskets. The first basket includes the two most imported crops, which are mainly rain-fed (wheat and barley). The second basket contains the two most exported crops, which are both irrigated and rain-fed (olives and dates). In the last basket we find the two highest economic blue water productive crops, which are mainly irrigated (tomatoes and potatoes). The results show the impact of each factor on net virtual water import of the selected crops during the period 1981-2010. Keywords: Virtual water, trade patterns, Aquacrop, Tunisia, water scarcity, water footprint.

  4. Change of water consumption and its potential influential factors in Shanghai: A cross-sectional study

    PubMed Central

    2012-01-01

    Background Different water choices affect access to drinking water with different quality. Previous studies suggested social-economic status may affect the choice of domestic drinking water. The aim of this study is to investigate whether recent social economic changes in China affect residents’ drinking water choices. Methods We conducted a cross-sectional survey to investigate residents’ water consumption behaviour in 2011. Gender, age, education, personal income, housing condition, risk perception and personal preference of a certain type of water were selected as potential influential factors. Univariate and backward stepwise logistic regression analyses were performed to analyse the relation between these factors and different drinking water choices. Basic information was compared with that of a historical survey in the same place in 2001. Self-reported drinking-water-related diarrhoea was found correlated with different water choices and water hygiene treatment using chi-square test. Results The percentage of tap water consumption remained relatively stable and a preferred choice, with 58.99% in 2001 and 58.25% in 2011. The percentage of bottled/barrelled water consumption was 36.86% in 2001 and decreased to 25.75% in 2011. That of household filtrated water was 4.15% in 2001 and increased to 16.00% in 2011. Logistic regression model showed strong correlation between one’s health belief and drinking water choices (P < 0.001). Age, personal income, education, housing condition, risk perception also played important roles (P < 0.05) in the models. Drinking-water-related diarrhoea was found in all types of water and improper water hygiene behaviours still existed among residents. Conclusions Personal health belief, housing condition, age, personal income, education, taste and if worm ever founded in tap water affected domestic drinking water choices in Shanghai. PMID:22708830

  5. [CCA of water beetles' distribution and environmental factors in lentic samples of north Changbai Mountain].

    PubMed

    We, Yulian; Ji, Lanzhu; Wang, Miao; Zhao, Min

    2002-01-01

    The relationship between 28 species water beetles in 12 lentic samples and environmental factors of North Chang-bai Mountain was studied by Cononical Correspondence Analysis (CCA). The results showed that degree of underwater humus and altitude are the major factors correlated with beetles distribution, and the correlation coefficients of environmental factors and axes of CCA were 0.8371 and 0.7206 respectively, while water temperature and plant density also had certain effects. Under the influence of environmental factors, the water beetles' populations were different in different habitat. Coelambus impressopunctatus, Colymbetes magnus, Helophorus browni, Haliplus spp. distributed in deep water pool. Water temperature was not important for those beetles. Ilybius sp. and Limnebius glabriventris correlated with altitude and humus.

  6. Using aerated gravel-packed contact bed and constructed wetland system for polluted river water purification: A case study in Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, J. L.; Tu, Y. T.; Chiang, P. C.; Chen, S. H.; Kao, C. M.

    2015-06-01

    The Ju-Liao Stream is one of the most contaminated streams in Kaohsiung City, Taiwan. A constructed wetland (CW) system was built in 2010 for polluted stream water purification and ecosystem improvement. An aerated gravel-packed contact bed (CB) system was built in 2011 and part of the stream water was treated by the CB before discharging to the CW. The influent rates of the CW and CB were approximately 5570 and 900 m3/d, respectively. The CW contained one free-water surface basin planted with emergent wetland plants, followed by the plug-flow channel-shaped free-water surface basin planted with emergent and floating wetland plants. The mean measured hydraulic loading rate (HLR), hydraulic retention time (HRT), water depth, and total volume of wetland system were 1.7 m/d, 0.68 d, 0.7 m, and 4400 m3, respectively. The aeration zone of the CB system had a dimension of 24 m (L) × 8 m (W) × 3 m (H), which was filled with gravels (average diameter = 5 cm) with a porosity of 0.4, and the aeration rate was 7.8 m3/min. Results show that the CB system was able to remove 69% of suspended solid (SS), 86% of biochemical oxygen demand (BOD), and 58% of total nitrogen (TN). Up to 82% of BOD and 27% of TN could be removed in the CW system. Removal efficiency of SS was affected by the growth of chlorophyll a in the CW system due to the growth of algae. The observed first-order decay rates (k) for BOD and TN in CB were 9.3 and 4.2 1/d, and the k values for BOD and TN removal in CW were 2.5 and 0.45 1/d. The high pollutant removal efficiencies in the CB system indicate that the system could enhance the organic and nutrient removal through the biological processes effectively. Sediments contained high total organic matter (1.9-4.5%), sediment total nitrogen (6.4-10.1 g/kg), sediment total phosphorus (0.59-0.94 g/kg), and sediment oxygen demand (0.9-4.1 g O2/m2 d). The organic and nutrient-abundant sediments resulted in reduced conditions (oxidation-reduction potential measurements

  7. Equivalence of conventional anti-picryl T suppressor factor in the contact sensitivity system and monoclonal anti-NP TsF3: their final non-specific effect via the T acceptor cell.

    PubMed

    Asherson, G L; Dorf, M E; Colizzi, V; Zembala, M; James, B M

    1984-11-01

    There is considerable confusion over whether the antigen-specific T suppressor factors (TsF) described by different authors are indeed equivalent. This paper investigates whether monoclonal TsF3, obtained from hybridomas derived from mice injected subcutaneously with NP derived spleen cells, is functionally equivalent to the conventional T suppressor factor, produced by mice injected intravenously with chemically reactive, water soluble haptene (picrylsulphonic acid and oxazolone thioglycolic acid). Comparison of monoclonal anti-NP TsF3 with conventional anti-picryl and anti-oxazolone T suppressor factor showed that both armed the non-specific T acceptor cell (Tacc) which was sensitive to cyclophosphamide and adult thymectomy. Moreover, non-specific inhibitor (nsINH) of the transfer of contact sensitivity was released when antigen, together with major histocompatibility complex products (MHC), reacted with conventional or monoclonal TsF on the surface of the non-specific T acceptor cell. The interaction of monoclonal TsF3 with antigen, which led to the release of NsINH, required the presence of MHC and was I-J restricted. However, there was no Igh-1 restriction. The equivalence of conventional anti-picryl and anti-oxazolone TsF has been demonstrated by arming the Tacc with a mixture of these two suppressor factors, and then triggering the release of nsINH with the mixed haptene 'picryl-oxazolone-lysine' which crosslinks separate molecules of TsF. A similar equivalence of conventional anti-oxazolone TsF and monoclonal anti-NP TsF3 was demonstrated using the mixed hapten 'NP-oxazolone-lysine' to trigger the release of nsINH. It was concluded that monoclonal TsF3 and conventional TsF were equivalent, and that both had an indirect mode of action through the non-specific T acceptor cell which led to the production of non-specific inhibitor.

  8. Equivalence of conventional anti-picryl T suppressor factor in the contact sensitivity system and monoclonal anti-NP TsF3: their final non-specific effect via the T acceptor cell.

    PubMed Central

    Asherson, G L; Dorf, M E; Colizzi, V; Zembala, M; James, B M

    1984-01-01

    There is considerable confusion over whether the antigen-specific T suppressor factors (TsF) described by different authors are indeed equivalent. This paper investigates whether monoclonal TsF3, obtained from hybridomas derived from mice injected subcutaneously with NP derived spleen cells, is functionally equivalent to the conventional T suppressor factor, produced by mice injected intravenously with chemically reactive, water soluble haptene (picrylsulphonic acid and oxazolone thioglycolic acid). Comparison of monoclonal anti-NP TsF3 with conventional anti-picryl and anti-oxazolone T suppressor factor showed that both armed the non-specific T acceptor cell (Tacc) which was sensitive to cyclophosphamide and adult thymectomy. Moreover, non-specific inhibitor (nsINH) of the transfer of contact sensitivity was released when antigen, together with major histocompatibility complex products (MHC), reacted with conventional or monoclonal TsF on the surface of the non-specific T acceptor cell. The interaction of monoclonal TsF3 with antigen, which led to the release of NsINH, required the presence of MHC and was I-J restricted. However, there was no Igh-1 restriction. The equivalence of conventional anti-picryl and anti-oxazolone TsF has been demonstrated by arming the Tacc with a mixture of these two suppressor factors, and then triggering the release of nsINH with the mixed haptene 'picryl-oxazolone-lysine' which crosslinks separate molecules of TsF. A similar equivalence of conventional anti-oxazolone TsF and monoclonal anti-NP TsF3 was demonstrated using the mixed hapten 'NP-oxazolone-lysine' to trigger the release of nsINH. It was concluded that monoclonal TsF3 and conventional TsF were equivalent, and that both had an indirect mode of action through the non-specific T acceptor cell which led to the production of non-specific inhibitor. PMID:6333385

  9. Intraspecies Variability Affects Heterotypic Biofilms of Porphyromonas gingivalis and Prevotella intermedia: Evidences of Strain-Dependence Biofilm Modulation by Physical Contact and by Released Soluble Factors

    PubMed Central

    Barbosa, Graziela Murta; Colombo, Andrea Vieira; Rodrigues, Paulo Henrique; Simionato, Maria Regina Lorenzetti

    2015-01-01

    It is well known that strain and virulence diversity exist within the population structure of Porphyromonas gingivalis. In the present study we investigate intra- and inter-species variability in biofilm formation of Porphyromonas gingivalis and partners Prevotella intermedia and Prevotella nigrescens. All strains tested showed similar hydrophobicity, except for P. gingivalis W83 which has roughly half of the hydrophobicity of P. gingivalis ATCC33277. An intraspecies variability in coaggregation of P. gingivalis with P. intermedia was also found. The association P. gingivalis W83/P. intermedia 17 produced the thickest biofilm and strain 17 was prevalent. In a two-compartment system P. gingivalis W83 stimulates an increase in biomass of strain 17 and the latter did not stimulate the growth of P. gingivalis W83. In addition, P. gingivalis W83 also stimulates the growth of P. intermedia ATCC25611 although strain W83 was prevalent in the association with P. intermedia ATCC25611. P. gingivalis ATCC33277 was prevalent in both associations with P. intermedia and both strains of P. intermedia stimulate the growth of P. gingivalis ATCC33277. FISH images also showed variability in biofilm structure. Thus, the outcome of the association P. gingivalis/P. intermedia seems to be strain-dependent, and both soluble factors and physical contact are relevant. The association P. gingivalis-P. nigrescens ATCC33563 produced larger biomass than each monotypic biofilm, and P. gingivalis was favored in consortia, while no differences were found in the two-compartment system. Therefore, in consortia P. gingivalis-P. nigrescens physical contact seems to favor P. gingivalis growth. The intraspecies variability found in our study suggests strain-dependence in ability of microorganisms to recognize molecules in other bacteria which may further elucidate the dysbiosis event during periodontitis development giving additional explanation for periodontal bacteria, such as P. gingivalis and P

  10. Stimulation of transforming growth factor-beta-1 and contact with type I collagen cooperatively facilitate irreversible transdifferentiation in proximal tubular cells.

    PubMed

    Yen, Chieh-Li; Li, Yi-Jung; Wu, Hsin-Hsu; Weng, Cheng-Hao; Lee, Cheng-Chia; Chen, Yung-Chang; Chang, Ming-Yang; Yen, Tzung-Hai; Hsu, Hsiang-Hao; Hung, Cheng-Chieh; Yang, Chih-Wei; Tian, Ya-Chung

    2016-02-01

    By transdifferentiation, proximal tubular cells (PTC) have been considered as a source of interstitial myofibroblasts. We examined the combined effect of transforming growth factor-beta-1 (TGF-β1) stimulation and contact with type I collagen on PTC transdifferentiation. Human kidney-2 cells were grown on type I substratum with the concurrent stimulation of TGF-β1. Following addition of TGF-β1, cells acquired an elongated fibroblastic appearance and an increase in α-smooth muscle actin (α-SMA) expression, a myofibroblastic marker. Upon addition of TGF-β1, E-cadherin expression, an epithelial marker, was reduced, while cytokeratin expression, another epithelial marker, remained unaltered. Following removal of TGF-β1, PTC regained an epithelial appearance and E-cadherin expression reverted to the unstimulated level, suggesting incomplete and reversible transdifferentiation. Addition of TGF-β1 to cells grown on type I collagen demonstrated a cooperatively increased α-SMA expression and decreased E-cadherin and cytokeratin expressions, suggesting more complete transdifferentiation. Co-stimulation of TGF-β1 and contact with type I collagen led to a stable cell phenotype and persistently decreased E-cadherin, which was not reversed upon removal of TGF-β1, indicating irreversible transdifferentiation. Addition of TGF-β1 or type I collagen caused a 4-fold increase in migratory cell number as compared to the control, whereas addition of both TGF-β1 and type I collagen led to an 11-fold increase. TGF-β1 alone results in a reversible and incomplete transdifferentiation. The combination of TGF-β1 and exposure to type I collagen leads to an irreversible and complete PTC transdifferentiation. Copyright © 2016 Chang Gung University. Published by Elsevier B.V. All rights reserved.

  11. Intraspecies Variability Affects Heterotypic Biofilms of Porphyromonas gingivalis and Prevotella intermedia: Evidences of Strain-Dependence Biofilm Modulation by Physical Contact and by Released Soluble Factors.

    PubMed

    Barbosa, Graziela Murta; Colombo, Andrea Vieira; Rodrigues, Paulo Henrique; Simionato, Maria Regina Lorenzetti

    2015-01-01

    It is well known that strain and virulence diversity exist within the population structure of Porphyromonas gingivalis. In the present study we investigate intra- and inter-species variability in biofilm formation of Porphyromonas gingivalis and partners Prevotella intermedia and Prevotella nigrescens. All strains tested showed similar hydrophobicity, except for P. gingivalis W83 which has roughly half of the hydrophobicity of P. gingivalis ATCC33277. An intraspecies variability in coaggregation of P. gingivalis with P. intermedia was also found. The association P. gingivalis W83/P. intermedia 17 produced the thickest biofilm and strain 17 was prevalent. In a two-compartment system P. gingivalis W83 stimulates an increase in biomass of strain 17 and the latter did not stimulate the growth of P. gingivalis W83. In addition, P. gingivalis W83 also stimulates the growth of P. intermedia ATCC25611 although strain W83 was prevalent in the association with P. intermedia ATCC25611. P. gingivalis ATCC33277 was prevalent in both associations with P. intermedia and both strains of P. intermedia stimulate the growth of P. gingivalis ATCC33277. FISH images also showed variability in biofilm structure. Thus, the outcome of the association P. gingivalis/P. intermedia seems to be strain-dependent, and both soluble factors and physical contact are relevant. The association P. gingivalis-P. nigrescens ATCC33563 produced larger biomass than each monotypic biofilm, and P. gingivalis was favored in consortia, while no differences were found in the two-compartment system. Therefore, in consortia P. gingivalis-P. nigrescens physical contact seems to favor P. gingivalis growth. The intraspecies variability found in our study suggests strain-dependence in ability of microorganisms to recognize molecules in other bacteria which may further elucidate the dysbiosis event during periodontitis development giving additional explanation for periodontal bacteria, such as P. gingivalis and P

  12. Factors influencing the precoat filtration of boiling water reactor water streams

    SciTech Connect

    Hermansson, H.P. ); Persson, G. ); Reinvall, A. )

    1994-10-01

    A series of studies on precoat filtration were carried out on condensate and preheater drains in the Swedish and Finnish boiling water reactors (BWRs). The goal was to increase knowledge about the precoat filtration process and to find physical and chemical means to improve the performance of the precoat filters in the condensate polishing plants. To achieve this goal a number of parameters, such as type of resin, bed depth, pH, oxygen and organic contaminant concentrations (measured total organic carbon), and corrosion product particle characteristics, were selected for the study. The work was mainly carried out in the power plants using an experimental facility fed with on-line sampled condensates and drains taken from the plant sampling lines. The main results are that there is a varying influence on precoat filtration from all the aforementioned parameters. The oxygen concentration, the concentration of organic contaminants, and the type of corrosion products are, however, the factors that have the strongest influence within the parameter ranges that are representative for BWR operation. The results are rather similar when the different units are compared. There are, however, some differences that could be mainly attributed to deviations in operation parameters and the subsequent differences in the corrosion product spectra. The mechanism for precoat filtration of corrosion products in BWR condensate is complex. The filtration behavior is to a large extent governed by competition between depth filtration and electrostatic interactions. During the early stages of the filtration cycle, electrostatic interaction is of great importance, whereas depth filtration becomes more important with increasing operating time. Rapid pressure drop buildup rates have been demonstrated to be caused by the presence of amorphous corrosion products. An effect from the presence of organic contaminants has been found, although this should be of little significance.

  13. Shigella Infections in Household Contacts of Pediatric Shigellosis Patients in Rural Bangladesh.

    PubMed

    George, Christine Marie; Ahmed, Shahnawaz; Talukder, Kaisar A; Azmi, Ishrat J; Perin, Jamie; Sack, R Bradley; Sack, David A; Stine, O Colin; Oldja, Lauren; Shahnaij, Mohammad; Chakraborty, Subhra; Parvin, Tahmina; Bhuyian, Sazzadul Islam; Bouwer, Edward; Zhang, Xiaotong; Hasan, Trisheeta N; Luna, Sharmin J; Akter, Fatema; Faruque, Abu S G

    2015-11-01

    To examine rates of Shigella infections in household contacts of pediatric shigellosis patients, we followed contacts and controls prospectively for 1 week after the index patient obtained care. Household contacts of patients were 44 times more likely to develop a Shigella infection than were control contacts (odds ratio 44.7, 95% CI 5.5-361.6); 29 (94%) household contacts of shigellosis patients were infected with the same species and serotype as the index patient's. Pulsed-field gel electrophoresis showed that 14 (88%) of 16 with infected contacts had strains that were indistinguishable from or closely related to the index patient's strain. Latrine area fly counts were higher in patient households compared with control households, and 2 patient household water samples were positive for Shigella. We show high susceptibility of household contacts of shigellosis patients to Shigella infections and found environmental risk factors to be targeted in future interventions.

  14. Shigella Infections in Household Contacts of Pediatric Shigellosis Patients in Rural Bangladesh

    PubMed Central

    Ahmed, Shahnawaz; Talukder, Kaisar A.; Azmi, Ishrat J.; Perin, Jamie; Sack, R. Bradley; Sack, David A; Stine, O. Colin; Oldja, Lauren; Shahnaij, Mohammad; Chakraborty, Subhra; Parvin, Tahmina; Bhuyian, Sazzadul Islam; Bouwer, Edward; Zhang, Xiaotong; Hasan, Trisheeta N.; Luna, Sharmin J.; Akter, Fatema; Faruque, Abu S.G.

    2015-01-01

    To examine rates of Shigella infections in household contacts of pediatric shigellosis patients, we followed contacts and controls prospectively for 1 week after the index patient obtained care. Household contacts of patients were 44 times more likely to develop a Shigella infection than were control contacts (odds ratio 44.7, 95% CI 5.5–361.6); 29 (94%) household contacts of shigellosis patients were infected with the same species and serotype as the index patient’s. Pulsed-field gel electrophoresis showed that 14 (88%) of 16 with infected contacts had strains that were indistinguishable from or closely related to the index patient’s strain. Latrine area fly counts were higher in patient households compared with control households, and 2 patient household water samples were positive for Shigella. We show high susceptibility of household contacts of shigellosis patients to Shigella infections and found environmental risk factors to be targeted in future interventions. PMID:26484778

  15. Infrared spectroscopy of acetone-water liquid mixtures. I. Factor analysis

    NASA Astrophysics Data System (ADS)

    Max, Jean-Joseph; Chapados, Camille

    2003-09-01

    Acetone and water mixtures covering the whole solubility range were measured by Fourier transform infrared attenuated total reflectance spectroscopy. In this system, only water can supply the hydrogen atoms necessary for hydrogen bonding. Using spectral windowing with factor analysis (FA), 10 principal factors were retrieved, five water and five acetone. Hydrogen bonding is observed on the carbonyl stretch band as water is introduced in the solution, redshifting the band further from its gas position than that observed in pure liquid acetone. This indicates that the hydrogen bonding is stronger than the acetone dipole-dipole interactions because it overrides them. A water molecule isolated in acetone is twice H bonded through its two H atoms; although both OH groups are H-bond donors, the OH stretch band is less redshifted (˜138 cm-1) than that of pure liquid water (˜401 cm-1). This is attributable to the two lone electron pairs remaining on the oxygen atom that sustain a large part of the OH valence bond strength. Hydrogen bonds on the water oxygen weaken both its OH valence bonds and modify the OH stretch band when water is added to the solution. The oxygen atoms of both water and acetone can accept 0, 1, and 2 H bonds given by water to yield three water and three acetone situations. Since these six situations are far less than the 10 principal factors retrieved by FA, other perturbations must be present to account for the difference. Although acetone and water are intermingled through H bonds, hydrates in the sense of an acetone molecule sequestering a number of water molecules or altering the H-bonding water network are not present because the principal factors evolve independently.

  16. Evaluation of factors affecting resolution of shallow water bottom features

    NASA Technical Reports Server (NTRS)

    Mason, C. C.; Norris, D. R.; Browne, I. D.

    1972-01-01

    To ensure good aerial photography, the effects that factors such as submergence depth, sun angle, film and filter type, exposure, aircraft altitude, and polarization have on the photographic resolution of an underwater object must be determined. Various subjects were photographed, such as the deck of a small submersible, colored and gray scale panels, and natural bottom features. No underwater resolution target was used.

  17. Evaluation and optimization of quartz resonant-frequency retuned fork force sensors with high Q factors, and the associated electric circuits, for non-contact atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Ooe, Hiroaki; Fujii, Mikihiro; Tomitori, Masahiko; Arai, Toyoko

    2016-02-01

    High-Q factor retuned fork (RTF) force sensors made from quartz tuning forks, and the electric circuits for the sensors, were evaluated and optimized to improve the performance of non-contact atomic force microscopy (nc-AFM) performed under ultrahigh vacuum (UHV) conditions. To exploit the high Q factor of the RTF sensor, the oscillation of the RTF sensor was excited at its resonant frequency, using a stray capacitance compensation circuit to cancel the excitation signal leaked through the stray capacitor of the sensor. To improve the signal-to-noise (S/N) ratio in the detected signal, a small capacitor was inserted before the input of an operational (OP) amplifier placed in an UHV chamber, which reduced the output noise from the amplifier. A low-noise, wideband OP amplifier produced a superior S/N ratio, compared with a precision OP amplifier. The thermal vibrational density spectra of the RTF sensors were evaluated using the circuit. The RTF sensor with an effective spring constant value as low as 1000 N/m provided a lower minimum detection limit for force differentiation. A nc-AFM image of a Si(111)-7 × 7 surface was produced with atomic resolution using the RTF sensor in a constant frequency shift mode; tunneling current and energy dissipation images with atomic resolution were also simultaneously produced. The high-Q factor RTF sensor showed potential for the high sensitivity of energy dissipation as small as 1 meV/cycle and the high-resolution analysis of non-conservative force interactions.

  18. Evaluation and optimization of quartz resonant-frequency retuned fork force sensors with high Q factors, and the associated electric circuits, for non-contact atomic force microscopy.

    PubMed

    Ooe, Hiroaki; Fujii, Mikihiro; Tomitori, Masahiko; Arai, Toyoko

    2016-02-01

    High-Q factor retuned fork (RTF) force sensors made from quartz tuning forks, and the electric circuits for the sensors, were evaluated and optimized to improve the performance of non-contact atomic force microscopy (nc-AFM) performed under ultrahigh vacuum (UHV) conditions. To exploit the high Q factor of the RTF sensor, the oscillation of the RTF sensor was excited at its resonant frequency, using a stray capacitance compensation circuit to cancel the excitation signal leaked through the stray capacitor of the sensor. To improve the signal-to-noise (S/N) ratio in the detected signal, a small capacitor was inserted before the input of an operational (OP) amplifier placed in an UHV chamber, which reduced the output noise from the amplifier. A low-noise, wideband OP amplifier produced a superior S/N ratio, compared with a precision OP amplifier. The thermal vibrational density spectra of the RTF sensors were evaluated using the circuit. The RTF sensor with an effective spring constant value as low as 1000 N/m provided a lower minimum detection limit for force differentiation. A nc-AFM image of a Si(111)-7 × 7 surface was produced with atomic resolution using the RTF sensor in a constant frequency shift mode; tunneling current and energy dissipation images with atomic resolution were also simultaneously produced. The high-Q factor RTF sensor showed potential for the high sensitivity of energy dissipation as small as 1 meV/cycle and the high-resolution analysis of non-conservative force interactions.

  19. Young children's hand contact activities: an observational study via videotaping in primarily outdoor residential settings.

    PubMed

    Auyeung, Willa; Canales, Robert A; Beamer, Paloma; Ferguson, Alesia C; Leckie, James O

    2006-09-01

    Microlevel activity time series (MLATS) data were gathered on hand contact activities of 38 children (1-6 years old) by videotaping in primarily outdoor residential environments. The videotape recordings were then translated into text files using a specialized software called VirtualTimingDevicetrade mark. Contact frequency (contacts/h), duration per contact (s/contact), and hourly contact duration (min/h) were summarized for outdoor hand contacts with 15 distinct object/surface categories ("Animal", "Body", "Clothes/Towels", "Fabric", "Floor", "Food", "Footwear", "Metal", "Non-dietary Water", "Paper/Wrapper", "Plastic", "Rock/Brick", "Toys", "Vegetation/Grass", and "Wood") and two aggregate object/surface categories ("Non-dietary objects/surfaces" and "Total objects/surfaces"). For outdoor both hand contacts with "Total objects/surfaces", contact frequencies ranged from 229.9 to 1517.7 contacts/h, median durations/contact ranged from < 1 to 5 s, and hourly contact durations ranged from 42.6 to 102.2 m/h. The data were analyzed for significant differences in hand contact activities as a function of (1) age, (2) location, (3) gender, and (4) hand. Significant differences (P < or = 0.05) were found for all four factors analyzed. Hourly contact durations with "Non-dietary objects/surfaces" and "Total objects/surfaces" increased with age (P = 0.01, rs = 0.42 and P = 0.005, rs = 0.46, respectively), while contact frequencies and hourly contact durations with "Wood" decreased with age (P = 0.02, rs = -0.38 and P = 0.05, rs = -0.32, respectively). Location was found to affect contact frequencies and hourly contact durations with certain objects/surfaces. For example, contact frequencies and hourly contact durations with "Fabric" were higher indoors (P = 0.02 for both), while contact frequencies and hourly contact durations with "Vegetation/Grass" were higher outdoors (P = 0.02 and P = 0.04, respectively). Girls had longer hourly contact durations with "Footwear" (P = 0

  20. Adsorption of submicrometer-sized cationic sterically stabilized polystyrene latex at the air-water interface: contact angle determination by ellipsometry.

    PubMed

    Hunter, Timothy N; Jameson, Graeme J; Wanless, Erica J; Dupin, Damien; Armes, Steven P

    2009-04-09

    Near-monodisperse, sterically stabilized cationic polystyrene latexes of either 122 or 310 nm diameter were prepared by aqueous emulsion polymerization using cheap, readily available reagents. At low pH, these latexes stabilized foams prepared by either hand-shaking or by using a foam column. SEM studies confirmed that the dried foam mainly comprised well-defined bilayers, which suggests that each air bubble is stabilized with a latex monolayer. Adsorption of the same latexes at the planar air-water interface was studied using the Langmuir-Blodgett trough technique. Surface pressure isotherms confirmed particle desorption from the interface on repeated compression of the latex monolayers. For the 122 nm latex at pH 2, ellipsometric analysis enabled a contact angle of approximately 43 degrees to be calculated from a simple two-layer model, which suggests that these particles have only moderate wettability. Similar results were obtained for the 310 nm latex, but the data were much less reliable in this case due to additional background particle scattering.

  1. A framework for developing research protocols for evaluation of microbial hazards and controls during production that pertain to the quality of agricultural water contacting fresh produce that may be consumed raw

    USDA-ARS?s Scientific Manuscript database

    Agricultural water may contact fresh produce during irrigation and/or when crop protection sprays (e.g., cooling to prevent sunburn, frost protection, and agrochemical mixtures) are applied. This document provides a framework for designing research studies that would add to our understanding of preh...

  2. [A review on carbon and water interactions of forest ecosystem and its impact factors].

    PubMed

    Song, Chun-lin; Sun, Xiang-yang; Wang, Gen-xu

    2015-09-01

    Interaction between carbon and water in forest ecosystem is a coupling process in terrestrial ecosystem, which is an indispensable aspect for the study of forest carbon pool, ecohydrological processes and the responses to global change. In the context of global change, the interaction and coupling of carbon and water in forest ecosystem has attracted much attention among scientists. In this paper, we reviewed the process mechanism of forest carbon and water relationships based on previous studies, which consisted of advance in forest water use efficiency, carbon and water interactions at different scales, scaling, and model simulation. We summed up the factors affecting for- est water and carbon interaction, including water condition, carbon dioxide enrichment, warming, nitrogen deposition, ozone concentration variation, solar radiation, and altitudinal gradients. Finally, we discussed the problems in the previous studies, and prospected the possible future research fields, among which we thought the inherent dynamics mechanism and scaling of forest carbon and water interactions should be enhanced.

  3. Factors influencing biological treatment of MTBE contaminated ground water

    SciTech Connect

    Stringfellow, William T.; Hines Jr., Robert D.; Cockrum, Dirk K.; Kilkenny, Scott T.

    2001-09-14

    Methyl tert-butyl ether (MTBE) contamination has complicated the remediation of gasoline contaminated sites. Many sites are using biological processes for ground water treatment and would like to apply the same technology to MTBE. However, the efficiency and reliability of MTBE biological treatment is not well documented. The objective of this study was to examine the operational and environmental variables influencing MTBE biotreatment. A fluidized bed reactor was installed at a fuel transfer station and used to treat ground water contaminated with MTBE and gasoline hydrocarbons. A complete set of chemical and operational data was collected during this study and a statistical approach was used to determine what variables were influencing MTBE treatment efficiency. It was found that MTBE treatment was more sensitive to up-set than gasoline hydrocarbon treatment. Events, such as excess iron accumulation, inhibited MTBE treatment, but not hydrocarbon treatment. Multiple regression analysis identified biomass accumulation and temperature as the most important variables controlling the efficiency of MTBE treatment. The influent concentration and loading of hydrocarbons, but not MTBE, also impacted MTBE treatment efficiency. The results of this study suggest guid