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Sample records for adsorption psa processes

  1. A new pressure swing adsorption (PSA) process for recovery of tritium from the ITER solid ceramic breeder helium purge gas

    SciTech Connect

    Sood, S.K.; Fong, C.; Kalyanam, K.M. ); Kveton, O.K. ); Busigin, A. ); Ruthven, D.M. )

    1992-03-01

    This paper reports on Pressure Swing Adsorption (PSA), a well established industrial process for separating and purifying industrial gases, it is proposed for recovery of hydrogen isotopes from the ITER (International Thermonuclear Experimental Reactor) solid breeder He purge stream. The PSA process has an inherent advantage over a recently proposed Temperature Swing Adsorption (TSA) design because it allows much faster cycling (10 vs. 480 min.) and therefore has significantly (48 times) lower tritium inventory. The maximum tritium inventory for a 10 minute PSA cycle is less than 0.5 g of tritium, thus meeting an important safety goal of ITER. The PSA process is based on using molecular sieve 5A at 77 K, with pressure cycling from 1-2 MPa during the adsorption cycle, to a rough vacuum during regeneration. Experiments have been carried out to confirm the H{sub 2}/He adsorption isotherms on molecular sieve 5A, and to develop new data points at low H{sub 2} partial pressures and a temperature of 77 K. A dynamic simulation model has been developed to facilitate system design and optimization.

  2. Simulation of Unique Pressure Changing Steps and Situations in Psa Processes

    NASA Technical Reports Server (NTRS)

    Ebner, Armin D.; Mehrotra, Amal; Knox, James C.; LeVan, Douglas; Ritter, James A.

    2007-01-01

    A more rigorous cyclic adsorption process simulator is being developed for use in the development and understanding of new and existing PSA processes. Unique features of this new version of the simulator that Ritter and co-workers have been developing for the past decade or so include: multiple absorbent layers in each bed, pressure drop in the column, valves for entering and exiting flows and predicting real-time pressurization and depressurization rates, ability to account for choked flow conditions, ability to pressurize and depressurize simultaneously from both ends of the columns, ability to equalize between multiple pairs of columns, ability to equalize simultaneously from both ends of pairs of columns, and ability to handle very large pressure ratios and hence velocities associated with deep vacuum systems. These changes to the simulator now provide for unique opportunities to study the effects of novel pressure changing steps and extreme process conditions on the performance of virtually any commercial or developmental PSA process. This presentation will provide an overview of the cyclic adsorption process simulator equations and algorithms used in the new adaptation. It will focus primarily on the novel pressure changing steps and their effects on the performance of a PSA system that epitomizes the extremes of PSA process design and operation. This PSA process is a sorbent-based atmosphere revitalization (SBAR) system that NASA is developing for new manned exploration vehicles. This SBAR system consists of a 2-bed 3-step 3-layer system that operates between atmospheric pressure and the vacuum of space, evacuates from both ends of the column simultaneously, experiences choked flow conditions during pressure changing steps, and experiences a continuously changing feed composition, as it removes metabolic CO2 and H20 from a closed and fixed volume, i.e., the spacecraft cabin. Important process performance indicators of this SBAR system are size, and the

  3. Final Report - Development of New Pressure Swing Adsorption (PSA) Technology to Recover High Valued Products from Chemical Plant and Refinery Waste Systems

    SciTech Connect

    Keith Ludwig

    2004-06-14

    Project Objective was to extend pressure swing adsorption (PSA) technology into previously under-exploited applications such as polyolefin production vent gas recovery and H2 recovery from refinery waste gases containing significant amounts of heavy hydrocarbons, aromatics, or H2S.

  4. Pressure swing adsorption processes: Intraparticle diffusion/convection models

    SciTech Connect

    Lu, Zuping; Loureiro, J.M.; LeVan, M.D. . Dept. of Chemical Engineering); Rodrigues, A.E. . School of Engineering)

    1993-11-01

    The dynamic behavior of a three-step one-column isothermal PSA process is assessed by simulation; three models are used: equilibrium, intraparticle diffusion, and intraparticle diffusion/convection. Two process performance parameters, product enrichment and recovery of the light component, are used to measure the separation performance. The effects of several operating variables on the process performance are addressed. Higher pressure ratios (P[sub h]/P[sub l]) and higher adsorption capacities increase the process performance. The process performance is practically independent of the step rates, although it can decrease if high feed rates are used together with large feed duration times. The limiting performance of the system is found in the absence of mass-transfer resistances. Intraparticle convection, enhancing mass transfer inside particles, increases the process performance relative to intraparticle diffusion alone; the improvement is limited by the equilibrium situation.

  5. Process, including PSA and membrane separation, for separating hydrogen from hydrocarbons

    DOEpatents

    Baker, Richard W.; Lokhandwala, Kaaeid A.; He, Zhenjie; Pinnau, Ingo

    2001-01-01

    An improved process for separating hydrogen from hydrocarbons. The process includes a pressure swing adsorption step, a compression/cooling step and a membrane separation step. The membrane step relies on achieving a methane/hydrogen selectivity of at least about 2.5 under the conditions of the process.

  6. Optimal synthesis of a pressure swing adsorption process for CO2 capture

    SciTech Connect

    Agarwal, A.; Biegler, L.; Zitney, S.

    2008-01-01

    The emission of carbon dioxide from cement industry and power plants that burn fossil fuels is the major cause for the accumulation of CO2 in the atmosphere, which causes long-range environmental problems. One option to mitigate the emission of CO2 is to capture it from the emission sources and store it to the ocean or depleted oil field or use it for enhanced oil recovery. CO2 recovery has been achieved by gas absorption employing solutions of carbonates and alkanolamines. However, this process is energy-intensive for the regeneration of solvent and also faces problems due to corrosion. Recently, the pressure swing adsorption (PSA) process has been considered as an alternative to the absorption process. PSA processes have been widely applied for the removal of CO2 from various feed mixtures, such as CO2 in the steam reformer off gas, landfill gas and natural gas. In all these commercial PSA cycles, the weakly adsorbed component in the mixture is the desired product and enriching the strongly adsorbed CO2 is not a concern. On the other hand, for the capture of CO2 for sequestration, it is necessary to concentrate the CO2 to a high purity to reduce the compression and transportation cost. Thus, it is necessary to develop a PSA cycle by which a high-purity product for the strongly adsorbed component with a high recovery is obtained. A multitude of PSA cycles and adsorbents have been developed for producing highly pure heavy component (CO2) from feedstock with low CO2 concentration. Kikkinides et al. suggested a 4-bed 4-step process with activated carbon as the sorbent and could recover 68% of CO2 at 99.997% purity. Chue et al. compared activated carbon and zeolite 13X on a 3-bed 7-step process and concluded that the latter is better than the former for CO2 recovery. However, the CO2 recovery was low in their process due to the lack of a countercurrent step in the chosen cycle. Choi et al. reported more than 70% CO2 recovery at more than 90% purity for a modified 3

  7. Ammonia Process by Pressure Swing Adsorption

    SciTech Connect

    Dr Felix Jegede

    2010-12-27

    The overall objective of the project is to design, develop and demonstrate a technically feasible and commercially viable system to produce ammonia along with recovery of the products by adsorption separation methods and significantly decrease the energy requirement in ammonia production. This is achieved through a significantly more efficient ammonia psa recovery system. The new ammonia recovery system receives the reactor effluents and achieves complete ammonia recovery, (which completely eliminates the energy intensive refrigeration and condensation system currently used in ammonia production). It also recovers the unused reactants and recycles them back to the reactor, free of potential reactor contaminants, and without the need for re-compression and re-heat of recycle stream thereby further saving more energy. The result is a significantly lower energy consumption, along with capital cost savings.

  8. Finite Element Modeling of Adsorption Processes for Gas Separation and Purification

    SciTech Connect

    Humble, Paul H.; Williams, Richard M.; Hayes, James C.

    2009-09-22

    Pacific Northwest National Laboratory (PNNL) has expertise in the design and fabrication of automated radioxenon collection systems for nuclear explosion monitoring. In developing new systems there is an ever present need to reduce size, power consumption and complexity. Most of these systems have used adsorption based techniques for gas collection and/or concentration and purification. These processes include pressure swing adsorption, vacuum swing adsorption, temperature swing adsorption, gas chromatography and hybrid processes that combine elements of these techniques. To better understand these processes, and help with the development of improved hardware, a finite element software package (COMSOL Multiphysics) has been used to develop complex models of these adsorption based operations. The partial differential equations used include a mass balance for each gas species and adsorbed species along with a convection conduction energy balance equation. These equations in conjunction with multicomponent temperature dependent isotherm models are capable of simulating separation processes ranging from complex multibed PSA processes, and multicomponent temperature programmed gas chromatography, to simple two component temperature swing adsorption. These numerical simulations have been a valuable tool for assessing the capability of proposed processes and optimizing hardware and process parameters.

  9. Defluoridation of drinking water using adsorption processes.

    PubMed

    Loganathan, Paripurnanda; Vigneswaran, Saravanamuthu; Kandasamy, Jaya; Naidu, Ravi

    2013-03-15

    Excessive intake of fluoride (F), mainly through drinking water, is a serious health hazard affecting humans worldwide. There are several methods used for the defluoridation of drinking water, of which adsorption processes are generally considered attractive because of their effectiveness, convenience, ease of operation, simplicity of design, and for economic and environmental reasons. In this paper, we present a comprehensive and a critical literature review on various adsorbents used for defluoridation, their relative effectiveness, mechanisms and thermodynamics of adsorption, and suggestions are made on choice of adsorbents for various circumstances. Effects of pH, temperature, kinetics and co-existing anions on F adsorption are also reviewed. Because the adsorption is very weak in extremely low or high pHs, depending on the adsorbent, acids or alkalis are used to desorb F and regenerate the adsorbents. However, adsorption capacity generally decreases with repeated use of the regenerated adsorbent. Future research needs to explore highly efficient, low cost adsorbents that can be easily regenerated for reuse over several cycles of operations without significant loss of adsorptive capacity and which have good hydraulic conductivity to prevent filter clogging during the fixed-bed treatment process.

  10. SEPARATION PROCESS USING COMPLEXING AND ADSORPTION

    DOEpatents

    Spedding, J.H.; Ayers, J.A.

    1958-06-01

    An adsorption process is described for separating plutonium from a solution of neutron-irradiated uranium containing ions of a compound of plutonium and other cations. The method consists of forming a chelate complex compound with plutoniunn ions in the solution by adding a derivative of 8- hydroxyquinoline, which derivative contains a sulfonic acid group, and adsorbing the remaining cations from the solution on a cation exchange resin, while the complexed plutonium remains in the solution.

  11. ION EXCHANGE ADSORPTION PROCESS FOR PLUTONIUM SEPARATION

    DOEpatents

    Boyd, G.E.; Russell, E.R.; Taylor, M.D.

    1961-07-11

    Ion exchange processes for the separation of plutonium from fission products are described. In accordance with these processes an aqueous solution containing plutonium and fission products is contacted with a cation exchange resin under conditions favoring adsorption of plutonium and fission products on the resin. A portion of the fission product is then eluted with a solution containing 0.05 to 1% by weight of a carboxylic acid. Plutonium is next eluted with a solution containing 2 to 8 per cent by weight of the same carboxylic acid, and the remaining fission products on the resin are eluted with an aqueous solution containing over 10 per cent by weight of sodium bisulfate.

  12. Adsorption of carbon black using carboxymethyl chitosan in deinking process

    NASA Astrophysics Data System (ADS)

    Muryeti, Budimulyani, Estuti; Sinurat, Ellya

    2017-03-01

    The study about synthesis, characterization, and application carboxymethyl chitosan as adsorbent in deinking process was conducted. Adsorption of carbon black onto carboxymethyl chitosan has been investigated in a batch system. This research was conducted to obtain the adsorption capacity of carboxymethyl chitosan. The experiments were carried out to study the effect of carbon black concentration, contact time and dosage of carboxymethyl chitosan to the adsorption capacity of carboxymethyl chitosan. The optimum condition of carbon black adsorption was achieved at contact time of 60 min and weight doses of 1.0 g. The adsorption capacity of carboxymethyl chitosan was 14.34 mg/g and the adsorption effectivity was 70.54%. The result indicates that carboxymethyl chitosan could be used as adsorbent of carbon black in deinking process.

  13. The PSA: Planetary Science Archive

    NASA Astrophysics Data System (ADS)

    Barthelemy, Maud; Metselaar, Harold; Martinez, Santa; Heather, David; Vazquez, Jose Luis; Manaud, Nicolas; Ortiz, Iñaki; Arviset, Christophe; Osuna, Pedro

    2010-05-01

    Scientific and engineering data from ESA's planetary missions are made accessible to the world-wide scientific community via the Planetary Science Archive (PSA). The PSA consists of online services incorporating search, preview, download, notification and delivery basket functionality. Besides data from the GIOTTO spacecraft and several ground-based cometary observations, the PSA contains data from the Mars Express, Venus Express, Rosetta, and Huygens missions. Preparation for the release of data from the SMART-1 spacecraft is ongoing. The focus of the PSA activities is on the long-term preservation of data and knowledge from ESA's planetary missions. Scientific users can access the data online using several interfaces: - The Classical Interface allows complex parameter based queries, providing the end user with a facility to complete very specific searches on meta-data and geometrical parameters. By nature, this interface requires careful use and heavy interaction with the end-user to input and control the relevant search parameters. - The Map-based Interface is currently operational only for Mars Express HRCS and OMEGA data. This interface allows an end-user to specify a region-of-interest by dragging a box onto a base map of Mars. From this interface, it is possible to directly visualize query results. The Map-based and Classical interfaces are linked and cross-compatible. If a user defines a region-of-interest in the Map-based interface, the results can be refined by entering more detailed search parameters in the Classical interface. - The Dataset Browser Interface is designed for more experienced users, and allows for direct browsing and access of the data set content through ftp-tree search. Each dataset contains documentation and calibration information in addition to the scientific or engineering data. All data are prepared by the corresponding instrument teams, mostly located in Europe. PSA staff supports the instrument teams in the full archiving process

  14. The PSA: Planetary Science Archive

    NASA Astrophysics Data System (ADS)

    Barthelemy, M.; Metselaar, H.; Martinez, S.; Heather, D.; Vazquez, J. L.; Wirth, K.; Manaud, N.; Ortiz, I.; Arviset, C.; Fernandez, M.

    2009-04-01

    Scientific and engineering data from ESA's planetary missions are made accessible to the world-wide scientific community via the Planetary Science Archive (PSA). The PSA consists of online services incorporating search, preview, download, notification and delivery basket functionality. Besides data from the GIOTTO spacecraft and several ground-based cometary observations, the PSA contains data from the Mars Express, Venus Express, Rosetta, and Huygens missions. Preparation for the release of data from the SMART-1 spacecraft is ongoing. The focus of the PSA activities is on the long-term preservation of data and knowledge from ESA's planetary missions. Scientific users can access the data online using several interfaces: The Classical Interface allows complex parameter based queries, providing the end user with a facility to complete very specific searches on meta-data and geometrical parameters. By nature, this interface requires careful use and heavy interaction with the end-user to input and control the relevant search parameters. The Map-based Interface is currently operational only for Mars Express HRCS and OMEGA data. This interface allows an end-user to specify a region-of-interest by dragging a box onto a base map of Mars. From this interface, it is possible to directly visualize query results. The Map-based and Classical interfaces are linked and cross-compatible. If a user defines a region-of-interest in the Map-based interface, the results can be refined by entering more detailed search parameters in the Classical interface. The Dataset Browser Interface is designed for more experienced users, and allows for direct browsing and access of the data set content through ftp-tree search. Each dataset contains documentation and calibration information in addition to the scientific or engineering data. All data are prepared by the corresponding instrument teams, mostly located in Europe. PSA staff supports the instrument teams in the full archiving process

  15. The PSA: Planetary Science Archive

    NASA Astrophysics Data System (ADS)

    Barthelemy, M.; Martinez, S.; Heather, D.; Vazquez, J. L.; Arviset, C.; Osuna, P.; PSA development Team

    2012-04-01

    Scientific and engineering data from ESA's planetary missions are made accessible to the world-wide scientific community via the Planetary Science Archive (PSA). The PSA consists of online services incorporating search, preview, download, notification and delivery basket functionality. Besides data from the GIOTTO spacecraft and several ground-based cometary observations, the PSA contains data from the Mars Express, Venus Express, Rosetta, SMART-1 and Huygens missions. The focus of the PSA activities is on the long-term preservation of data and knowledge from ESA's planetary missions. Scientific users can access the data online using several interfaces: - The Advanced Search Interface allows complex parameter based queries, providing the end user with a facility to complete very specific searches on meta-data and geometrical parameters. By nature, this interface requires careful use and heavy interaction with the end-user to input and control the relevant search parameters. - The Map-based Interface is currently operational only for Mars Express HRCS and OMEGA data. This interface allows an end-user to specify a region-of-interest by dragging a box onto a base map of Mars. From this interface, it is possible to directly visualize query results. The Map-based and Advanced interfaces are linked and cross-compatible. If a user defines a region-of-interest in the Map-based interface, the results can be refined by entering more detailed search parameters in the Advanced interface. - The FTP Browser Interface is designed for more experienced users, and allows for direct browsing and access of the data set content through ftp-tree search. Each dataset contains documentation and calibration information in addition to the scientific or engineering data. All data are prepared by the corresponding instrument teams, mostly located in Europe. PSA supports the instrument teams in the full archiving process, from the definition of the data products, meta-data and product labels

  16. Adsorption Processes in Spacecraft Environmental Control and Life Support Systems

    NASA Technical Reports Server (NTRS)

    Bauman, Liese Dall; Finn, John E.; Kliss, Mark (Technical Monitor)

    1998-01-01

    The environmental control and life support system on a spacecraft must maintain a safe and comfortable environment in which the crew can live and work. The system's functions include supplying the crew with oxygen and water as well as removing carbon dioxide, water vapor, and trace contaminants from cabin air. Although open-loop systems have been used in the past, logistics and safety factors of current and future missions in space make near-complete recycling of the cabin's air and water imperative. The recycling process may include separation and reduction of carbon dioxide, removal of trace gas-phase contaminants, recovery and purification of humidity condensate, purification and polishing of wastewater streams, and other processes. Several of these operations can be performed totally or in part by adsorption processes. These processes are frequently good candidates to perform separations and purifications in space due to their gravity independence, high reliability, relatively high energy efficiency, design flexibility, technological maturity, and regenerability. For these reasons, adsorption has historically played a key role in life support on U.S. and Russian piloted spacecraft. This article focuses on three current spacecraft life support applications that often use adsorption technology: gas-phase trace contaminant control, carbon dioxide removal from cabin air, and potable water recovery from waste streams. In each application, adsorption technology has been selected for use on the International Space Station. The requirements, science, and hardware for each of these applications are discussed. Eventually, human space exploration may lead to construction of planetary habitats. These habitats may provide additional opportunities for use of adsorption processes, such as control of greenhouse gas composition, and may have different requirements and resources available to them, such as gases present in the planetary atmosphere. Adsorption separation and

  17. [Recovery of CO from an ammonia plant tail gas with pressure swing adsorption process].

    PubMed

    Yi, Hong-hong; Ning, Ping; Hao, Ji-ming; Yang, Hao

    2004-09-01

    Ammonia plant tail gas is an important CO source for C1 chemistry if an efficient separation/purification technology is available. Presented is pressure swing adsorption using a home made catalyst PU1 for recovery of CO from ammonia plant tail gas. A performance comparison of PU1 with a commercial zeolite was also presented. The pilot plant experiments were carried out in an intermission one-bed PSA unit with ammonia plant tail gas and a feed flow rate of 0.2-0.8 m3/h. The purity and recovery of CO was studied under various operating conditions. The operating conditions for the process were optimized and an optimum cyclic sequence of operation steps was proposed. A good performance of PU1 in the process was experimentally demonstrated. Product gas with a CO purity over 98% could be produced at a CO recovery of 75% for a feed gas CO concentration of 30% and gas pressure of 0.3 MPa.

  18. Adsorption processes in spacecraft environmental control and life support systems

    NASA Technical Reports Server (NTRS)

    DallBauman, L. A.; Finn, J. E.

    1999-01-01

    The environmental control and life support system on a spacecraft maintains a safe and comfortable environment in which the crew can live and work by supplying oxygen and water and by removing carbon dioxide, water vapor, and trace contaminants from cabin air. Although open-loop systems have been used successfully in the past for short-duration missions, the economics of current and future long-duration missions in space will make nearly complete recycling of air and water imperative. A variety of operations will be necessary to achieve the goal of nearly complete recycling. These include separation and reduction of carbon dioxide, removal of trace gas-phase contaminants, recovery and purification of humidity condensate, purification and polishing of wastewater streams, and others. Several of these can be performed totally or in part by adsorption processes. These processes are good candidates to perform separations and purifications in space due to their gravity independence, high reliability, relative high energy efficiency, design flexibility, technological maturity, and regenerative nature. For these reasons, adsorption has historically played a key role in life support on U.S. and Russian piloted spacecraft. Among the life support applications that can be achieved through use of adsorption technology are removal of trace contaminants and carbon dioxide from cabin air and recovery of potable water from waste streams. In each of these cases adsorption technology has been selected for use onboard the International Space Station. The requirements, science, and hardware for these applications are discussed. Human space exploration may eventually lead to construction of planetary habitats. These habitats may provide additional opportunities for use of adsorption processes, such as control of greenhouse gas composition, and may have different resources available to them, such as gases present in the planetary atmosphere. Separation and purification processes based on

  19. Adsorption processes in spacecraft environmental control and life support systems.

    PubMed

    DallBauman, L A; Finn, J E

    1999-01-01

    The environmental control and life support system on a spacecraft maintains a safe and comfortable environment in which the crew can live and work by supplying oxygen and water and by removing carbon dioxide, water vapor, and trace contaminants from cabin air. Although open-loop systems have been used successfully in the past for short-duration missions, the economics of current and future long-duration missions in space will make nearly complete recycling of air and water imperative. A variety of operations will be necessary to achieve the goal of nearly complete recycling. These include separation and reduction of carbon dioxide, removal of trace gas-phase contaminants, recovery and purification of humidity condensate, purification and polishing of wastewater streams, and others. Several of these can be performed totally or in part by adsorption processes. These processes are good candidates to perform separations and purifications in space due to their gravity independence, high reliability, relative high energy efficiency, design flexibility, technological maturity, and regenerative nature. For these reasons, adsorption has historically played a key role in life support on U.S. and Russian piloted spacecraft. Among the life support applications that can be achieved through use of adsorption technology are removal of trace contaminants and carbon dioxide from cabin air and recovery of potable water from waste streams. In each of these cases adsorption technology has been selected for use onboard the International Space Station. The requirements, science, and hardware for these applications are discussed. Human space exploration may eventually lead to construction of planetary habitats. These habitats may provide additional opportunities for use of adsorption processes, such as control of greenhouse gas composition, and may have different resources available to them, such as gases present in the planetary atmosphere. Separation and purification processes based on

  20. Reduced-order model for dynamic optimization of pressure swing adsorption processes

    SciTech Connect

    Agarwal, A.; Biegler, L.; Zitney, S.

    2007-01-01

    Over the past decades, pressure swing adsorption (PSA) processes have been widely used as energy-efficient gas and liquid separation techniques, especially for high purity hydrogen purification from refinery gases. The separation processes are based on solid-gas equilibrium and operate under periodic transient conditions. Models for PSA processes are therefore multiple instances of partial differential equations (PDEs) in time and space with periodic boundary conditions that link the processing steps together. The solution of this coupled stiff PDE system is governed by steep concentrations and temperature fronts moving with time. As a result, the optimization of such systems for either design or operation represents a significant computational challenge to current differential algebraic equation (DAE) optimization techniques and nonlinear programming algorithms. Model reduction is one approach to generate cost-efficient low-order models which can be used as surrogate models in the optimization problems. The study develops a reduced-order model (ROM) based on proper orthogonal decomposition (POD), which is a low-dimensional approximation to a dynamic PDE-based model. Initially, a representative ensemble of solutions of the dynamic PDE system is constructed by solving a higher-order discretization of the model using the method of lines, a two-stage approach that discretizes the PDEs in space and then integrates the resulting DAEs over time. Next, the ROM method applies the Karhunen-Loeve expansion to derive a small set of empirical eigenfunctions (POD modes) which are used as basis functions within a Galerkin's projection framework to derive a low-order DAE system that accurately describes the dominant dynamics of the PDE system. The proposed method leads to a DAE system of significantly lower order, thus replacing the one obtained from spatial discretization before and making optimization problem computationally-efficient. The method has been applied to the dynamic

  1. Effect of tribology processes on adsorption of albumin

    NASA Astrophysics Data System (ADS)

    Yan, Yu; Yang, Hongjuan; Wang, Linghe; Su, Yanjing; Qiao, Lijie

    2016-03-01

    As soon as artificial joint replacements are implanted into patients, the adsorption of proteins can occur. Joint implants operate in a protein-rich and relatively corrosive environment under tribological contact. The contacted area acted as an anodic part and the rest of the surface was more cathodic. Therefore, the adsorption of proteins is different in and outside the wear track. Adsorbed proteins would denature during rubbing and a tribofilm could form. The tribofilm can lubricate the surface and act as a barrier to corrosion damage. However, to observe the adsorption of proteins in situ has always been a challenge. Scanning Kelvin probe force microscope (SKPFM) was used to study the adsorption of albumin on the surface of CoCrMo alloy under simulated tribology movement. Fluorescence microscopy (FM) was employed to reveal the protein molecules in the wear scar. It was found that albumin molecules can decrease the surface potential and accelerate the corrosion process. In the wear track, albumin denatured and changed the surface potential as time progressed.

  2. New Adsorption Cycles for Carbon Dioxide Capture and Concentration

    SciTech Connect

    James Ritter; Armin Ebner; Steven Reynolds Hai Du; Amal Mehrotra

    2008-07-31

    The objective of this three-year project was to study new pressure swing adsorption (PSA) cycles for CO{sub 2} capture and concentration at high temperature. The heavy reflux (HR) PSA concept and the use of a hydrotalcite like (HTlc) adsorbent that captures CO{sub 2} reversibly at high temperatures simply by changing the pressure were two key features of these new PSA cycles. Through the completion or initiation of nine tasks, a bench-scale experimental and theoretical program has been carried out to complement and extend the process simulation study that was carried out during Phase I (DE-FG26-03NT41799). This final report covers the entire project from August 1, 2005 to July 31, 2008. This program included the study of PSA cycles for CO{sub 2} capture by both rigorous numerical simulation and equilibrium theory analysis. The insight gained from these studies was invaluable toward the applicability of PSA for CO{sub 2} capture, whether done at ambient or high temperature. The rigorous numerical simulation studies showed that it is indeed possible to capture and concentrate CO{sub 2} by PSA. Over a wide range of conditions it was possible to achieve greater than 90% CO{sub 2} purity and/or greater than 90% CO{sub 2} recovery, depending on the particular heavy reflux (HR) PSA cycle under consideration. Three HR PSA cycles were identified as viable candidates for further study experimentally. The equilibrium theory analysis, which represents the upper thermodynamic limit of the performance of PSA process, further validated the use of certain HR PSA cycles for CO{sub 2} capture and concentration. A new graphical approach for complex PSA cycle scheduling was also developed during the course of this program. This new methodology involves a priori specifying the cycle steps, their sequence, and the number of beds, and then following a systematic procedure that requires filling in a 2-D grid based on a few simple rules, some heuristics and some experience. It has been

  3. Modeling two-rate adsorption kinetics: Two-site, two-species, bilayer and rearrangement adsorption processes.

    PubMed

    Tripathi, Sumit; Tabor, Rico F

    2016-08-15

    The adsorption kinetics of many systems show apparent two-rate processes, where there appears to be resolved fast and slow adsorption steps. Such non-standard adsorption processes cannot be accounted for by conventional modeling methods, motivating new approaches. In this work, we present four different models that can account for two-rate adsorption and are based upon physically realistic processes - two adsorbing species, two surface sites having different energies, bilayer formation and molecular rearrangement modes. Each model is tested using a range of conditions, and the characteristic behavior is explored and compared. In these models, the effects of mass transport and bulk concentration are also accounted for, making them applicable in systems which are transport-limited or attachment-limited, or intermediate between the two. The applicability of these models is demonstrated by fitting exemplar experimental data for each of the four models, selecting the model on the basis of the known physical behavior of the adsorption kinetics. These models can be applied in a wide range of systems, from stagnant adsorption in large volume water treatment to highly dynamic flow conditions relevant to printing, coating and processing applications.

  4. Reduced-Order Model for Dynamic Optimization of Pressure Swing Adsorption

    SciTech Connect

    Agarwal, Anshul; Biegler, L.T.; Zitney, S.E.

    2007-11-01

    The last few decades have seen a considerable increase in the applications of adsorptive gas separation technologies, such as pressure swing adsorption (PSA). From an economic and environmental point of view, hydrogen separation and carbon dioxide capture from flue gas streams are the most promising applications of PSA. With extensive industrial applications, there is a significant interest for an efficient modeling, simulation, and optimization strategy. However, the design and optimization of the PSA processes have largely remained an experimental effort because of the complex nature of the mathematical models describing practical PSA processes. The separation processes are based on solid-gas equilibrium and operate under periodic transient conditions. Models for PSA processes are therefore multiple instances of partial differential equations (PDEs) in time and space with periodic boundary conditions that link the processing steps together and high nonlinearities arising from non-isothermal effects. The computational effort required to solve such systems is usually quite expensive and prohibitively time consuming. Besides this, stringent product specifications, required by many industrial processes, often lead to convergence failures of the optimizers. The solution of this coupled stiff PDE system is governed by steep concentrations and temperature fronts moving with time. As a result, the optimization of such systems for either design or operation represents a significant computational challenge to current differential algebraic equation (DAE) optimization techniques and nonlinear programming algorithms. Sophisticated optimization strategies have been developed and applied to PSA systems with significant improvement in the performance of the process. However, most of these approaches have been quite time consuming. This gives a strong motivation to develop cost-efficient and robust optimization strategies for PSA processes. Moreover, in case of flowsheet

  5. Lysozyme immobilization via adsorption process using sulphonic acid functionalized silane grafted copolymer.

    PubMed

    Anirudhan, T S; Rauf, Tharun A

    2013-07-01

    A unique silane based adsorbent material, [stearyl alcohol (SA)-grafted-epichlorohydrin (E)]-grafted-aminoproypyl silanetriol (APST) was synthesized and functionalized with sulphonyl groups via sulphonation process [(SA-g-E)-g-APST/SO3H]. The adsorbent material characterization was done by FTIR, XRD, and TGA analysis. Immobilization of protein Lysozyme (LYZ) using batch adsorption process was carried out for studying the protein-particle interaction. The most suitable pH for maximum adsorption was found to be 7.0. Pseudo-second-order kinetic model was found to be the best fit and the adsorption equilibrium was attained within 3h. Studies on diffusion parameters explained that the adsorption mechanism was controlled by film diffusion mode. The adsorption process was then evaluated using the various isotherm models and the Sips isotherm model proved to be the best fit with a maximum adsorption capacity of 37.68 mg/g. The isotherm favorability of the adsorption process was calculated by calculating the separation factor (R(L)) and the values confirmed the favorability of the adsorption process. Studies on adsorption percentage with respect to temperature and thermodynamic studies revealed that adsorption process is exothermic, spontaneous with maximum entropy. Batch adsorption/desorption studies in acidic medium, for over six cycles showed the repeatability and regeneration capability of the adsorbent material (SA-g-E)-g-APST/SO3H.

  6. Lattice Boltzmann simulation of gas-solid adsorption processes at pore scale level

    NASA Astrophysics Data System (ADS)

    Zhou, L.; Qu, Z. G.; Chen, L.; Tao, W. Q.

    2015-11-01

    A two-dimensional lattice Boltzmann (LB) approach was established to implement kinetic concentration boundary conditions in interfacial mass-transfer processes and to simulate the adsorption process in porous media at pore scale and mesoscopic levels. A general treatment was applied to conduct three types of concentration boundary conditions effectively and accurately. Applicability for adsorption was verified by two benchmark examples, which were representative of the interparticle mass transport and intraparticle mass transport in the adsorption system, respectively. The gas-solid adsorption process in reconstructed porous media at the pore scale level was numerically investigated. Mass-transfer processes of the adsorption reaction were simulated by executing Langmuir adsorption kinetics on surfaces of adsorbent particles. Meanwhile, the homogeneous solid diffusion model (HSDM) was used for mass transport in interior particles. The transient adsorbed amount was obtained in detail, and the impact of flow condition, porosity, and adsorbent particle size on the entire dynamic adsorption performance was investigated. The time needed to approach steady state decreased with increased fluid velocity. Transient adsorption capability and time consumption to equilibrium were nearly independent of porosity, whereas increasing pore size led to a moderating adsorption rate and more time was consumed to approach the saturation adsorption. Benefiting from the advantages of the LB method, both bulk and intraparticle mass transfer performances during adsorption can be obtained using the present pore scale approach. Thus, interparticle mass transfer and intraparticle mass transfer are the two primary segments, and intraparticle diffusion has the dominant role.

  7. Fabrication of copper patterns on flexible substrate by patterning-adsorption-plating process.

    PubMed

    Chang, Yu; Yang, Chao; Zheng, Xin-Yao; Wang, Dong-Yu; Yang, Zhen-Guo

    2014-01-22

    A novel patterning-adsorption-plating process to additively fabricate copper patterns is developed. Functional ink with ion-adsorption nanoparticles was inkjet printed on PET substrate to form the patterned adsorption film. Catalytic ion was adsorbed by amino groups in the adsorption film, and catalyzed the electroless plating of copper. The mercapto groups introduced to the film enhance the reliability of the patterns. Specific solvent used in the ink increase the surface roughness of the adsorption film, leading to a better adhesion of the patterns. The prepared copper patterns show excellent conductivity about the same with bulk copper and good adhesion on PET.

  8. Hybrid Adsorption-Membrane Biological Reactors for Improved Performance and Reliability of Perchlorate Removal Processes

    DTIC Science & Technology

    2008-12-01

    carbon supply for the autotrophic perchlorate reducing bacteria. The membrane used in the reactor is a hollow-fiber microfiltration membrane made from...1 HYBRID ADSORPTION- MEMBRANE BIOLOGICAL REACTORS FOR IMPROVED PERFORMANCE AND RELIABILITY OF PERCHLORATE REMOVAL PROCESSES L.C. Schideman...Center Champaign, IL 61826, USA ABSTRACT This study introduces the novel HAMBgR process (Hybrid Adsorption Membrane Biological Reactor) and

  9. Carbon dioxide pressure swing adsorption process using modified alumina adsorbents

    DOEpatents

    Gaffney, T.R.; Golden, T.C.; Mayorga, S.G.; Brzozowski, J.R.; Taylor, F.W.

    1999-06-29

    A pressure swing adsorption process for absorbing CO[sub 2] from a gaseous mixture containing CO[sub 2] comprises introducing the gaseous mixture at a first pressure into a reactor containing a modified alumina adsorbent maintained at a temperature ranging from 100 C and 500 C to adsorb CO[sub 2] to provide a CO[sub 2] laden alumina adsorbent and a CO[sub 2] depleted gaseous mixture and contacting the CO[sub 2] laden adsorbent with a weakly adsorbing purge fluid at a second pressure which is lower than the first pressure to desorb CO[sub 2] from the CO[sub 2] laden alumina adsorbent. The modified alumina adsorbent which is formed by depositing a solution having a pH of 3.0 or more onto alumina and heating the alumina to a temperature ranging from 100 C and 600 C, is not degraded by high concentrations of water under process operating conditions. 1 fig.

  10. Carbon dioxide pressure swing adsorption process using modified alumina adsorbents

    DOEpatents

    Gaffney, Thomas Richard; Golden, Timothy Christopher; Mayorga, Steven Gerard; Brzozowski, Jeffrey Richard; Taylor, Fred William

    1999-01-01

    A pressure swing adsorption process for absorbing CO.sub.2 from a gaseous mixture containing CO.sub.2 comprising introducing the gaseous mixture at a first pressure into a reactor containing a modified alumina adsorbent maintained at a temperature ranging from 100.degree. C. and 500.degree. C. to adsorb CO.sub.2 to provide a CO.sub.2 laden alumina adsorbent and a CO.sub.2 depleted gaseous mixture and contacting the CO.sub.2 laden adsorbent with a weakly adsorbing purge fluid at a second pressure which is lower than the first pressure to desorb CO.sub.2 from the CO.sub.2 laden alumina adsorbent. The modified alumina adsorbent which is formed by depositing a solution having a pH of 3.0 or more onto alumina and heating the alumina to a temperature ranging from 100.degree. C. and 600.degree. C., is not degraded by high concentrations of water under process operating conditions.

  11. Analysis of the use of adsorption processes in trigeneration systems

    NASA Astrophysics Data System (ADS)

    Grzebielec, Andrzej; Rusowicz, Artur

    2013-12-01

    The trigeneration systems for production of cold use sorption refrigeration machines: absorption and adsorption types. Absorption systems are characterized namely by better cooling coefficient of performance, while the adsorptive systems are characterized by the ability to operate at lower temperatures. The driving heat source temperature can be as low as 60-70 °C. Such temperature of the driving heat source allows to use them in district heating systems. The article focuses on the presentation of the research results on the adsorption devices designed to work in trigeneration systems.

  12. Reverse osmosis concentrate treatment via a PAC-MF accumulative countercurrent adsorption process.

    PubMed

    Zhao, Chunxia; Gu, Ping; Cui, Hangyu; Zhang, Guanghui

    2012-01-01

    Organic pollutants in reverse osmosis (RO) concentrates from wastewater reclamation are mainly comprised of low molecular weight biorefractory compounds. Generally, advanced oxidation methods for oxidizing these organics require a relatively high level of energy consumption. In addition, conventional adsorption removal methods require a large dose of activated carbon. However, the dose can be reduced if its full adsorption capacity can be used. Therefore, the combined technology of powdered activated carbon (PAC) adsorption and microfiltration (MF) membrane filtration was studied to develop a countercurrent two-stage adsorption process. A PAC accumulative adsorption prediction method was proposed based on the verification of a PAC multi-stage adsorption capacity equation. Moreover, the prediction method was amended for a more accurate prediction of the effluent quality because adsorption isotherm constants were affected by the initial adsorbate concentration. The required PAC dose for the accumulative countercurrent two-stage adsorption system was 0.6 g/L, whereas that of the conventional adsorption process was 1.05 g/L when the dilution factor(F) was 0.1 and the COD and DOC removal rates were set to 70% and 68.1%, respectively. Organic pollutants were satisfactorily removed with less consumption of PAC. Effluent from this combined technology can be further reclaimed by an RO process to improve the overall recovery rate to between 91.0% and 93.8% with both economic and environmental benefits.

  13. proPSA — EDRN Public Portal

    Cancer.gov

    ProPSA (-2), or [-2]proPSA, is a PSA isoform which has a leader peptide (-2) amino acids at its N terminal region and does not interact with ACT or alpha-2-macroglobulin or spermidine and therefore is detected as a separate isoform. ProPSA is produced primarily in the peripheral zone of the prostate gland and therefore is very useful in distinguishing between prostate cancer patients with PSA range of 2-10, from those who have BPH. Percent proPSA is the ratio of proPSA to free PSA. In July 2012 the FDA approved an assay measuring levels of [-2]proPSA for monitoring and diagnostic purposes.

  14. Effect of aging process on adsorption of diethyl phthalate in soils amended with bamboo biochar.

    PubMed

    Zhang, Xiaokai; Sarmah, Ajit K; Bolan, Nanthi S; He, Lizhi; Lin, Xiaoming; Che, Lei; Tang, Caixian; Wang, Hailong

    2016-01-01

    Biochar is a carbonaceous sorbent and can be used as a potential material to reduce the bioavailability of organic pollutants in contaminated soils. In the present study, the adsorption and desorption of diethyl phthalate (DEP) onto soils amended with bamboo biochar was investigated with a special focus on the effect of biochar application rates and aging conditions on the adsorption capacity of the soils. Biochar amendment significantly enhanced the soil adsorption of DEP that increased with increasing application rates of biochar. However, the adsorption capacity decreased by two aging processes (alternating wet and dry, and constantly moist). In the soil with low organic carbon (OC) content, the addition of 0.5% biochar (without aging) increased the adsorption by nearly 98 times compared to the control, and exhibited the highest adsorption capacity among all the treatments. In the soil with high OC content, the adsorption capacity in the treatment of 0.5% biochar without aging was 3.5 and 3 times greater than those of the treatments of biochar aged by alternating wet and dry, and constantly moist, respectively. Moreover, constantly moist resulted in a greater adsorption capacity than alternating wet and dry treatments regardless of biochar addition. This study revealed that biochar application enhanced soil sorption of DEP, however, the enhancement of the adsorption capacity was dependent on the soil organic carbon levels, and aging processes of biochar.

  15. Interactions of xanthines with activated carbon. I. Kinetics of the adsorption process

    NASA Astrophysics Data System (ADS)

    Navarrete Casas, R.; García Rodriguez, A.; Rey Bueno, F.; Espínola Lara, A.; Valenzuela Calahorro, C.; Navarrete Guijosa, A.

    2006-06-01

    Because of their pharmaceutical and industrial applications, we have studied the adsorption of xanthine derivates (caffeine and theophylline) by activated carbon. To this end, we examined kinetic, equilibrium and thermodynamic aspects of the process. This paper reports the kinetics results. The experimental results indicate that the process was first order in C and the overall process was assumed to involve a single, reversible adsorption-desorption process obeying a kinetic law postulated by us.

  16. Kinetic Study of Adsorption Processes in Solution: An Undergraduate Physical Chemistry Experiment.

    ERIC Educational Resources Information Center

    Casado, Julio; And Others

    1985-01-01

    Background information, apparatus needed, procedures used, and results obtained are provided for a simple kinetic method for the monitoring of adsorption processes. The method, which involved adsorption of crystal violet onto activated carbon, is suitable for classroom and/or research purposes. (JN)

  17. Use of adsorption process to remove organic mercury thimerosal from industrial process wastewater.

    PubMed

    Velicu, Magdalena; Fu, Hongxiang; Suri, Rominder P S; Woods, Kevin

    2007-09-30

    Carbon adsorption process is tested for removal of high concentration of organic mercury (thimerosal) from industrial process wastewater, in batch and continuously flow through column systems. The organic mercury concentration in the process wastewater is about 1123 mg/L due to the thimerosal compound. Four commercially available adsorbents are tested for mercury removal and they are: Calgon F-400 granular activated carbon (GAC), CB II GAC, Mersorb GAC and an ion-exchange resin Amberlite GT73. The adsorption capacity of each adsorbent is described by the Freundlich isotherm model at pH 3.0, 9.5 and 11.0 in batch isotherm experiments. Acidic pH was favorable for thimerosal adsorption onto the GACs. Columns-in-series experiments are conducted with 30-180 min empty bed contact times (EBCTs). Mercury breakthrough of 30 mg/L occurred after about 47 h (96 Bed Volume Fed (BVF)) of operation, and 97 h (197 BVF) with 120 min EBCT and 180 min EBCT, respectively. Most of the mercury removal is attributed to the 1st adsorbent column. Increase in contact time by additional adsorbent columns did not lower the effluent mercury concentration below 30 mg/L. However, at a lower influent wastewater pH 3, the mercury effluent concentration decreased to less than 7 mg/L for up to 90 h of column operation (183 BVF).

  18. Robust design of binary countercurrent adsorption separation processes

    SciTech Connect

    Storti, G. ); Mazzotti, M.; Morbidelli, M.; Carra, S. )

    1993-03-01

    The separation of a binary mixture, using a third component having intermediate adsorptivity as desorbent, in a four section countercurrent adsorption separation unit is considered. A procedure for the optimal and robust design of the unit is developed in the frame of Equilibrium Theory, using a model where the adsorption equilibria are described through the constant selectivity stoichiometric model, while mass-transfer resistances and axial mixing are neglected. By requiring that the unit achieves complete separation, it is possible to identify a set of implicity constraints on the operating parameters, that is, the flow rate ratios in the four sections of the unit. From these constraints explicit bounds on the operating parameters are obtained, thus yielding a region in the operating parameters space, which can be drawn a priori in terms of the adsorption equilibrium constants and the feed composition. This result provides a very convenient tool to determine both optimal and robust operating conditions. The latter issue is addressed by first analyzing the various possible sources of disturbances, as well as their effect on the separation performance. Next, the criteria for the robust design of the unit are discussed. Finally, these theoretical findings are compared with a set of experimental results obtained in a six port simulated moving bed adsorption separation unit operated in the vapor phase.

  19. PSA — EDRN Public Portal

    Cancer.gov

    KLK3, also known as PSA, or prostate specific antigen, a member of the kallikrein subgroup of serine proteases, is one of the fifteen kallikrein subfamily members located in a cluster on chromosome 19. Kallikreins are increasingly thought to be involved in carcinogenesis, and many act as cancer biomarkers. The product of the KLK3 gene is a protease present in seminal plasma. It is thought to function normally in the liquefaction of seminal coagulum. KLK3, or PSA, is well known for its role in diagnosing and monitoring prostate cancer. There are several isoforms of KLK3, generated by alternate splicing and transcript variants.

  20. Review of APR+ Level 2 PSA. Revision 2

    SciTech Connect

    Lehner, John R.; Mubayi, Vinod; Pratt, W. Trevor; Kim, Do Sam; Cho, Yong Jin; Cho, Sang Jin; Kim, In Goo

    2012-02-17

    Brookhaven National Laboratory (BNL) assisted the Korea Institute of Nuclear Safety (KINS) in reviewing the Level 2 Probabilistic Safety Assessment (PSA) of the APR+ Advanced Pressurized Water Reactor (PWR) prepared by the Korea Hydro & Nuclear Power Co., Ltd (KHNP) and KEPCO Engineering & Construction Co., Inc. (KEPCO-E&C). The work described in this report involves a review of the APR+ Level 2 PSA submittal [Ref. 1]. The PSA and, therefore, the review is limited to consideration of accidents initiated by internal events. As part of the review process, the review team also developed three sets of Requests for Additional Information (RAIs). These RAIs were provided to KHNP and KEPCO-E&C for their evaluation and response. This final detailed report documents the review findings for each technical element of the PSA and includes consideration of all of the RAIs made by the reviewers as well as the associated responses. This final report was preceded by an interim report [Ref. 2] that focused on identifying important issues regarding the PSA. In addition, a final meeting on the project was held at BNL on November 21-22, 2011, where BNL and KINS reviewers discussed their preliminary review findings with KHNP and KEPCO-E&C staffs. Additional information obtained during this final meeting was also used to inform the review findings of this final report. The review focused not only on the robustness of the APR+ design to withstand severe accidents, but also on the capability and acceptability of the Level 2 PSA in terms of level of detail and completeness. The Korean nuclear regulatory authorities will decide whether the PSA is acceptable and the BNL review team is providing its comments for KINS consideration. Section 2.0 provides the basis for the BNL review. Section 3.0 presents the review of each technical element of the PSA. Conclusions and a summary are presented in Section 4.0. Section 5.0 contains the references.

  1. Determining Interactions in PSA models: Application to a Space PSA

    SciTech Connect

    C. Smith; E. Borgonovo

    2010-06-01

    This paper addresses use of an importance measure interaction study of a probabilistic risk analysis (PSA) performed for a hypothetical aerospace lunar mission. The PSA methods used in this study follow the general guidance provided in the NASA Probabilistic Risk Assessment Procedures Guide for NASA Managers and Practitioners. For the PSA portion, we used phased-based event tree and fault tree logic structures are used to model a lunar mission, including multiple phases (from launch to return to the Earth surface) and multiple critical systems. Details of the analysis results are not provided in this paper – instead specific basic events are denoted by number (e.g., the first event is 1, the second is 2, and so on). However, in the model, we used approximately 150 fault trees and over 800 basic events. Following analysis and truncation of cut sets, we were left with about 400 basic events to evaluate. We used this model to explore interactions between different basic events and systems. These sensitivity studies provide high-level insights into features of the PSA for the hypothetical lunar mission.

  2. Prostate-Specific Antigen (PSA) Test

    MedlinePlus

    ... prostate cancer recurrence. However, a single elevated PSA measurement in a patient who has a history of ... than with BPH . One recently approved test combines measurement of a form of pro-PSA called [-2] ...

  3. Insights from the WGRISK workshop on the PSA of advanced and new reactors

    SciTech Connect

    Georgescu, G.; Ahn, K. I.; Amri, A.

    2012-07-01

    Probabilistic Safety Assessment /Probabilistic Risk Assessment for new and advanced reactors is recognized as an essential complement of the deterministic approaches to achieve improved safety and performances of new nuclear power plants, comparing to the operating plants. However, the development of PSA to these reactors is encountered to concurrent challenges, mainly due to the limited available design information, as well as due to potentially new initiating events, accident sequences and phenomena. The use of PSA in the decision making process is also challenging since the resulting PSA may not sufficiently reflect the future as-built, as-operated plant information. In order to address these aspects, the OECD/NEA/WGRISK initiated two coordinated tasks on 'PSA for Advanced Reactors' and 'PSA in the frame of Design and Commissioning of New NPPs'. In this context, a joint workshop was organized by OECD, during which related subjects were presented and discussed, including PSA for generation IV reactors, PSA for evolutionary reactors, PSA for small modular reactors, severe accidents and Level 2 PSA, Level 3 PSA and consequences analysis, digital I and C modeling, passive systems reliability, safety-security interface, as well as the results of the surveys performed in the frame of theses WGRISK tasks. (authors)

  4. Detoxification of pesticide waste via activated carbon adsorption process.

    PubMed

    Foo, K Y; Hameed, B H

    2010-03-15

    Concern about environmental protection has increased over the years from a global viewpoint. To date, the percolation of pesticide waste into the groundwater tables and aquifer systems remains an aesthetic issue towards the public health and food chain interference. With the renaissance of activated carbon, there has been a consistent growing interest in this research field. Confirming the assertion, this paper presents a state of art review of pesticide agrochemical practice, its fundamental characteristics, background studies and environmental implications. Moreover, the key advance of activated carbon adsorption, its major challenges together with the future expectation are summarized and discussed. Conclusively, the expanding of activated carbon adsorption represents a plausible and powerful circumstance, leading to the superior improvement of environmental preservation.

  5. Adsorption of Chrysoidine R by using fly ash in batch process.

    PubMed

    Matheswaran, Manickam; Karunanithi, Thirugnanam

    2007-06-25

    This investigation deals with effective utilization of fly ash as adsorbent for the removal of Chrysoidine R from the aqueous solution. The fly ash is a major byproduct generated in coal-based thermal power plants and has good potential for use as an adsorbent. A series of experiments were carried out in a batch adsorption technique to obtain the effect of process variables viz. contact time, pH (2, 4, 6 and 8) initial concentration of the dye (400, 600, 800 and 1000mgL(-1)), amount of the adsorbent (125, 250, 375 and 500mgL(-1)), and temperature (303, 313, 323 and 333K) on adsorption. The concentration of dye was determined by spectrophotometer. The results showed that as the amount of the adsorbent was increased, the percentage of dye removal increased accordingly; higher adsorption percentage was observed at lower concentration of chrysoidine. The adsorption data were analyzed using Langmuir and Freundlich isotherms. The adsorption was found to obey pseudo-first order kinetics. An intra particle diffusion model was used to fit the experimental data. The thermodynamic parameters such as standard change in free energy, enthalpy and entropy of adsorption have been calculated. Adsorption of Chrysoidine R on fly ash was found to be an exothermic reaction.

  6. Association between polymorphisms in the prostate-specific antigen (PSA) promoter and release of PSA.

    PubMed

    Sävblom, C; Giwercman, A; Malm, J; Halldén, C; Lundin, K; Lilja, H; Giwercman, Y

    2009-10-01

    Variations in serum prostate-specific antigen (PSA) have been ascribed to A/G nucleotide polymorphisms located at -158 bp (rs266882) and -4643 bp (rs925013), relative to the transcription start site within the promoter of the PSA gene. PSA is also an androgen receptor target (AR) gene and polymorphisms in AR gene are known to affect AR function. Our objective was to compare the impact of these A/G polymorphisms separately or in combination with AR CAG micro satellite on regulation of PSA secretion into seminal plasma and blood in young men. Leukocyte DNA was extracted from 291 conscripts and genotyping performed with the Sequenom Mass Array System. PSA was measured with an immunofluorometric assay. Linear regression analysis was used to test the association of polymorphism frequencies with serum and seminal plasma levels of PSA. PSA gene polymorphisms at -158 bp or -4643 bp did not alone influence total PSA (tPSA) levels in seminal plasma or in blood. Homozygotes for the A-allele at -158 bp in combination with CAG > 22 had significantly higher serum levels of tPSA than subjects carrying the G-allele (p = 0.01). In conclusion, the PSA gene polymorphisms did not importantly influence the levels of tPSA in seminal plasma or in blood. tPSA in serum was influenced by interactions between PSA promoter variants and AR CAG polymorphism.

  7. [5ARI and PSA: open questions.

    PubMed

    Tubaro, Andrea; Puccini, Federica; De Nunzio, Cosimo

    2014-09-23

    No consensus has ever been reached on the predictive value of serum prostate specific antigen(PSA) for the diagnosis of prostate cancer. Limitations of PSA testing in clinical practice have beenoften discussed in the peer-reviewed literature following data derived from clinical trials such as theProstate Cancer Prevention Trial (PCPT) and the Reduction by Dutasteride of Prostate Cancer Events(REDUCE) study that showed a linear rise in the risk of prostate cancer with increasing PSA levels.Benign prostatic hyperplasia is a known confounding factor for the use of PSA as a marker of prostatecancer. Increased prostate volume observed with ageing, urinary retention, acute and chronicinflammatory conditions of the prostate, sexual activity and digital rectal examination may all cause anincrease of PSA values. Both finasteride and dutasteride, 5-alpha reductase inhibitors (5ARI) used inthe treatment of BPH, are known to induce a significant decrease of serum PSA levels close to 50%.The observed change in PSA values following 5ARI treatment has raised questions about the accuracyof PSA testing for the early diagnosis of prostate cancer in patients on finasteride/dutasteride treatment.Careful analysis of data from various clinical trials on pharmacological treatment of LUTS due toBPH suggested that the accuracy of PSA testing is not just maintained but rather increased following5ARI use. Then, the question of PSA accuracy during 5ARI treatment can be considered closed.

  8. Lattice Boltzmann simulation of the gas-solid adsorption process in reconstructed random porous media.

    PubMed

    Zhou, L; Qu, Z G; Ding, T; Miao, J Y

    2016-04-01

    The gas-solid adsorption process in reconstructed random porous media is numerically studied with the lattice Boltzmann (LB) method at the pore scale with consideration of interparticle, interfacial, and intraparticle mass transfer performances. Adsorbent structures are reconstructed in two dimensions by employing the quartet structure generation set approach. To implement boundary conditions accurately, all the porous interfacial nodes are recognized and classified into 14 types using a proposed universal program called the boundary recognition and classification program. The multiple-relaxation-time LB model and single-relaxation-time LB model are adopted to simulate flow and mass transport, respectively. The interparticle, interfacial, and intraparticle mass transfer capacities are evaluated with the permeability factor and interparticle transfer coefficient, Langmuir adsorption kinetics, and the solid diffusion model, respectively. Adsorption processes are performed in two groups of adsorbent media with different porosities and particle sizes. External and internal mass transfer resistances govern the adsorption system. A large porosity leads to an early time for adsorption equilibrium because of the controlling factor of external resistance. External and internal resistances are dominant at small and large particle sizes, respectively. Particle size, under which the total resistance is minimum, ranges from 3 to 7 μm with the preset parameters. Pore-scale simulation clearly explains the effect of both external and internal mass transfer resistances. The present paper provides both theoretical and practical guidance for the design and optimization of adsorption systems.

  9. Opium consumption is negatively associated with serum prostate-specific antigen (PSA), free PSA, and percentage of free PSA levels.

    PubMed

    Safarinejad, Mohammad Reza; Asgari, Seyyed Alaeddin; Farshi, Alireza; Iravani, Shahrokh; Khoshdel, Alireza; Shekarchi, Babak

    2013-01-01

    Addiction to opium continues to be a major worldwide medical and social problem. The study addressing the association between opium consumption and serum prostate-specific antigen (PSA) level is lacking. We determined the effects of opium consumption on serum PSA levels in opium-addict men. Our study subjects comprised 438 opium-addict men with a mean age of 52.2 ± 6.4 years (group 1). We compared these men with 446 men who did not indicate current or past opium use (group 2). Serum total PSA (tPSA), free PSA (fPSA), % fPSA, and sex hormones were compared between the 2 groups. The mean serum tPSA level was significantly lower in group 1 (1.05 ng/mL) than in controls (1.45 ng/mL) (P = 0.001). Opium consumption was also associated with lower fPSA (P = 0.001) and % fPSA (P = 0.001). Serum free testosterone level in opium-addict patients (132.5 ± 42 pg/mL) was significantly lower than that in controls (156.2 ± 43 pg/mL) (P = 0.03). However, no significant correlation existed between tPSA and free testosterone levels (r = 0.28, 95% CI, -0.036 to 0.51, P = 0.34). Among the patients with cancer in group 1, 35% were found to have high-grade tumor (Gleason score ≥ 7) compared with 26.7% in group 2 (P = 0.02). Total PSA and fPSA were strongly correlated with duration of opium use (r = -0.06, 95% CI, -0.04 to -0.08, P = 0.0001; and r = -0.05, 95% CI, -0.03 to -0.07, P = 0.0001, respectively). Opium consumption is independently and negatively associated with serum tPSA, fPSA, and % fPSA levels.

  10. Azo dye Acid Red 27 decomposition kinetics during ozone oxidation and adsorption processes.

    PubMed

    Beak, Mi H; Ijagbemi, Christianah O; Kim, Dong S

    2009-05-01

    To elucidate the effects of ozone dosage, catalysts, and temperature on azo dye decomposition rate in treatment processes, the decomposition kinetics of Acid Red 27 by ozone was investigated. Acid Red 27 decomposition rate followed the first-order reaction with complete dye discoloration in 20 min of ozone reaction. The dye decay rate increases as ozone dosage increases. Using Mn, Zn and Ni as transition metal catalysts during the ozone oxidation process, Mn displayed the greatest catalytic effect with significant increase in the rate of decomposition. The rate of decomposition decreases with increase in temperature and beyond 40 degrees C, increase in decomposition rate was followed by a corresponding increase in temperature. The FT-IR spectra in the range of 1,000-1,800 cm(-1) revealed specific band variations after the ozone oxidation process, portraying structural changes traceable to cleavage of bonds in the benzene ring, the sulphite salt group, and the C-N located beside the -N = N- bond. From the (1)H-NMR spectra, the breaking down of the benzene ring showed the disappearance of the 10 H peaks at 7-8 ppm, which later emerged with a new peak at 6.16 ppm. In a parallel batch test of azo dye Acid Red 27 adsorption onto activated carbon, a low adsorption capacity was observed in the adsorption test carried out after three minutes of ozone injection while the adsorption process without ozone injection yielded a high adsorption capacity.

  11. A facile method for improving the covalent crosslinking adsorption process of catalase immobilization.

    PubMed

    Ran, Jingyu; Jia, Shaoyi; Liu, Yong; Zhang, Wei; Wu, Songhai; Pan, Xiaolei

    2010-08-01

    In this paper, we introduced a polydiol (mixture of 1,2-propanediol, 1,3-propanediol, and 2,3-butanediol) to improve the covalent crosslinking adsorption process of immobilized catalase onto chitosan beads. The adsorption behavior was investigated by means of adsorption kinetics and adsorption isotherm. The protein content in crosslinking agent required for approximately 45 min to reach the relative equilibrium, and the protein content in solution of the control group and the pretreated group were 6.63 microg/mL and 6.20 microg/mL, respectively. The maximum catalase adsorption capacity of the control group and the pretreated group were observed as 23.118 microg/g and 25.688 microg/g at pH 7.0, respectively. Temperature profiles showed that 40 degrees C was the ideal temperature for active domain of catalase, and the relative activity of pretreated group was 1.12 times higher than that of the control group. The K(m) value of the control group (67 mM) was higher than that of the pretreated group (54 mM). Thermal stability, operational stability, and the effect of surfactant on catalase adsorption were also explored in this study.

  12. Visualization and Measurement of Adsorption/Desorption Process of Ethanol in Activated Carbon Adsorber

    NASA Astrophysics Data System (ADS)

    Asano, Hitoshi; Murata, Kenta; Takenaka, Nobuyuki; Saito, Yasushi

    Adsorption refrigerator is one of the efficient tools for waste heat recovery, because the system is driven by heat at relative low temperature. However, the coefficient of performance is low due to its batch operation and the heat capacity of the adsorber. In order to improve the performance, it is important to optimize the configuration to minimize the amount of driving heat, and to clarify adsorption/desorption phenomena in transient conditions. Neutron radiography was applied to visualize and measure the adsorption amount distribution in an adsorber. The visualization experiments had been performed at the neutron radiography facility of E-2 port of Kyoto University Research Reactor. Activated carbon and ethanol were used as the adsorbent and refrigerant. From the acquired radiographs, adsorption amount was quantitatively measured by applying the umbra method using a checkered neutron absorber with boron powder. Then, transient adsorption and desorption processes of a rectangular adsorber with 84 mm in width, 50 mm in height and 20 mm in depth were visualized. As the result, the effect of fins in the adsorbent layer on the adsorption amount distribution was clearly visualized.

  13. AIR SEPARATION BY PRESSURE SWING ADSORPTION USING SUPERIOR ADSORBENTS

    SciTech Connect

    Ralph T. Yang

    2001-08-31

    Li-X zeolite (Si/Al = 1.0) is currently the best sorbent for use in the separation of air by adsorption processes. In particular, pressure swing adsorption (PSA) using zeolite sorbents is being increasingly used for air separation. Silver is also known to strongly affect the adsorptive properties of zeolites; and it is known that thermal vacuum dehydration of silver zeolites leads to the formation of silver clusters within the zeolite. In this work we have synthesized type X zeolites containing Ag and also varying mixtures of Li and Ag. In this project, we developed the Ag-containing zeolite as the best sorbent for air separation. We have also studied Co-ligand compounds as oxygen-selective sorbents. Syntheses, structural characterization and adsorption properties have been performed on all sorbents. The results are described in detail in 5 chapters.

  14. Coupling of Spinosad Fermentation and Separation Process via Two-Step Macroporous Resin Adsorption Method.

    PubMed

    Zhao, Fanglong; Zhang, Chuanbo; Yin, Jing; Shen, Yueqi; Lu, Wenyu

    2015-08-01

    In this paper, a two-step resin adsorption technology was investigated for spinosad production and separation as follows: the first step resin addition into the fermentor at early cultivation period to decrease the timely product concentration in the broth; the second step of resin addition was used after fermentation to adsorb and extract the spinosad. Based on this, a two-step macroporous resin adsorption-membrane separation process for spinosad fermentation, separation, and purification was established. Spinosad concentration in 5-L fermentor increased by 14.45 % after adding 50 g/L macroporous at the beginning of fermentation. The established two-step macroporous resin adsorption-membrane separation process got the 95.43 % purity and 87 % yield for spinosad, which were both higher than that of the conventional crystallization of spinosad from aqueous phase that were 93.23 and 79.15 % separately. The two-step macroporous resin adsorption method has not only carried out the coupling of spinosad fermentation and separation but also increased spinosad productivity. In addition, the two-step macroporous resin adsorption-membrane separation process performs better in spinosad yield and purity.

  15. Use of combined coagulation-adsorption process as pretreatment of landfill leachate

    PubMed Central

    2013-01-01

    Landfill leachate is an important pollution factor resulting from municipal landfill sites. Physical and chemical processes are the better option for pretreatment or full treatment of landfill leachate. This article presents a combination of pre-treatment method (coagulation and adsorption) for leachate collected from municipal solid waste open dumping site. Physico chemical characteristics of stabilized and fresh leachate were examined. Coagulation process was examined by using alum and ferric chloride. A low cost adsorbent, fly ash was used for adsorption studies. Coagulation studies were carried out for fresh and stabilized leachate. Adsorption studies have been conducted for alum pre-treated stabilized leachate. Effect of coagulant dose, adsorbent dose, pH and contact time were carried out. The effective optimum coagulant dosages were 0.6 g/L and 0.7 g/L for alum and ferric chloride respectively for stabilized leachate and incase of fresh leachate 0.8 g/L and 0.6 g/L for alum and ferric chloride respectively. For the alum pretreated stabilized leachate, the maximum COD removal is 28% using fly ash adsorbent with equilibrium time of 210 min and optimum dose of 6 g/L. Overall COD removal efficiency of 82% was obtained by coagulation using alum and adsorption using fly ash for stabilized leachate. The results obtained showed that combined coagulation and adsorption process can be used effectively for stabilized leachate treatment. PMID:23517661

  16. The adsorption and mass-transfer process of cationic red X-GRL dye on natural zeolite.

    PubMed

    Tian, Jingjing; Guan, Junfang; Gao, Huimin; Wen, Yafei; Ren, Zijie

    2016-01-01

    The adsorption behavior of natural zeolite was studied in order to determine the adsorption capacity and mass-transfer process of cationic red X-GRL (C(18)H(21)BrN(6)) onto the adsorbent. The adsorption tests to determine both the uptake capacity and the mass-transfer process at equilibrium were performed under batch conditions, which showed rapid uptake in general for the initial 5 min, corresponding to 92% total removal. The equilibrium adsorption capacity value (q(e,cal)) in pseudo-second-order kinetics was 13.51 mg/g at 293 K and the whole adsorption process was governed by physical adsorption with an endothermic, endothermic spontaneous nature. Adsorption tests indicated that the zeolite has great potential as an alternative low-cost material in the treatment of X-GRL drainage. However, the mass-transfer process to determine the rate-controlling steps showed that both film diffusion and pore diffusion were important in controlling the adsorption rate. The adsorption process was governed by film diffusion while pore diffusion was poor because the X-GRL molecules could not penetrate into the zeolite easily. The X-GRL molecules were only adsorbed on the external surface of the zeolite. Hence, to improve the adsorption capacity of natural zeolite further, modification to expand its micropores is necessary.

  17. Adsorption and Processes in Spacecraft Environmental Control and Life Support Systems

    NASA Technical Reports Server (NTRS)

    Dall-Bauman, Liese; Finn, John E.; Kliss, Mark (Technical Monitor)

    1997-01-01

    The environmental control and life support system on a spacecraft must maintain a safe and comfortable environment in which the crew can live and work. The system's functions include supplying the crew with oxygen and water, as well as removing carbon dioxide, water vapor, and trace contaminants from cabin air. Although open-loop systems have been used in the past, logistics and safety factors of current and future missions in space make near-complete recycling of the cabin's air and water desirable. The recycling process may include separation and reduction of carbon dioxide, removal of trace gas-phase contaminants, recovery and purification of humidity condensate, purification and polishing of wastewater streams, and other processes. Several of these operations can be performed totally or in part by adsorption processes. Adsorption processes are frequently good candidates for separation and purification in space by virtue of such characteristics as gravity independence, high reliability, relatively high energy efficiency, design flexibility, technological maturity, and regenerability. For these reasons, adsorption has historically played a key role in life support on U.S. and Russian piloted spacecraft. This article focuses on three current spacecraft life support applications that often use adsorption technology: carbon dioxide separation from cabin air, gas-phase trace contaminant control, and potable water recovery from waste streams. In each application, adsorption technology has been selected for use on the International Space Station. The requirements, science, and hardware for each application are discussed. Eventually, human space exploration may lead to construction of planetary habitats. These habitats may have additional applications, such as control of greenhouse gas composition and purification of hydroponic solutions, and may have different requirements and resources available to them, such as gases present in the planetary atmosphere. Adsorption

  18. Adsorption process to recover hydrogen from feed gas mixtures having low hydrogen concentration

    DOEpatents

    Golden, Timothy Christopher; Weist, Jr., Edward Landis; Hufton, Jeffrey Raymond; Novosat, Paul Anthony

    2010-04-13

    A process for selectively separating hydrogen from at least one more strongly adsorbable component in a plurality of adsorption beds to produce a hydrogen-rich product gas from a low hydrogen concentration feed with a high recovery rate. Each of the plurality of adsorption beds subjected to a repetitive cycle. The process comprises an adsorption step for producing the hydrogen-rich product from a feed gas mixture comprising 5% to 50% hydrogen, at least two pressure equalization by void space gas withdrawal steps, a provide purge step resulting in a first pressure decrease, a blowdown step resulting in a second pressure decrease, a purge step, at least two pressure equalization by void space gas introduction steps, and a repressurization step. The second pressure decrease is at least 2 times greater than the first pressure decrease.

  19. Adsorption Processes of Lead Ions on the Mixture Surface of Bentonite and Bottom Sediments.

    PubMed

    Hegedűsová, Alžbeta; Hegedűs, Ondrej; Tóth, Tomáš; Vollmannová, Alena; Andrejiová, Alena; Šlosár, Miroslav; Mezeyová, Ivana; Pernyeszi, Tímea

    2016-12-01

    The adsorption of contaminants plays an important role in the process of their elimination from a polluted environment. This work describes the issue of loading environment with lead Pb(II) and the resulting negative impact it has on plants and living organisms. It also focuses on bentonite as a natural adsorbent and on the adsorption process of Pb(II) ions on the mixture of bentonite and bottom sediment from the water reservoir in Kolíňany (SR). The equilibrium and kinetic experimental data were evaluated using Langmuir isotherm kinetic pseudo-first and pseudo-second-order rate equations the intraparticle and surface diffusion models. Langmuir isotherm model was successfully used to characterize the lead ions adsorption equilibrium on the mixture of bentonite and bottom sediment. The pseudo second-order model, the intraparticle and surface (film) diffusion models could be simultaneously fitted the experimental kinetic data.

  20. Adsorptive process design for the separation of hexane isomers using zeolites.

    PubMed

    Luna-Triguero, A; Gómez-Álvarez, P; Calero, S

    2017-02-15

    The product of catalytic isomerization is a mixture of linear and branched hydrocarbons that are in thermodynamic equilibrium, and their separation becomes necessary in the petrochemical industry. Zeolite 5A is usually industrially used to sieve alkane isomers, but its pore size allows only the separation of linear alkanes from the monobranched and dibranched alkanes by a kinetic mechanism. A more efficient approach to improve the average research octane number would be to adsorptively separate the di-methyl alkanes as products and recycle both the linear and mono-methyl alkanes to the isomerization reactor. Since the microscopic processes of adsorbates in zeolites are generally difficult or impossible to determine by experiments, especially in the case of mixtures, molecular simulation represents an attractive alternative. In this computational study, we propose a conceptual separation process for hexane isomers consisting of several adsorptive steps. Different zeolite topologies were examined for their ability to conduct this separation based on adsorption equilibrium and kinetics.

  1. Mathematical evaluation of activated carbon adsorption for surfactant recovery in a soil washing process.

    PubMed

    Ahn, Chi K; Lee, Min W; Lee, Dae S; Woo, Seung H; Park, Jong M

    2008-12-15

    The performances of various soil washing processes, including surfactant recovery by selective adsorption, were evaluated using a mathematical model for partitioning a target compound and surfactant in water/sorbent system. Phenanthrene was selected as a representative hazardous organic compound and Triton X-100 as a surfactant. Two activated carbons that differed in size (Darco 20-40 mesh and >100 mesh sizes) were used in adsorption experiments. The adsorption isotherms of the chemicals were used in model simulations for various washing scenarios. The optimal process conditions were suggested to minimize the dosage of activated carbon and surfactant and the number of washings. We estimated that the requirement of surfactant could be reduced to 33% of surfactant requirements (from 265 to 86.6g) with a reuse step using 9.1g activated carbon (>100 mesh) to achieve 90% removal of phenanthrene (initially 100mg kg-soil(-1)) with a water/soil ratio of 10.

  2. Optimizing the lanthanum adsorption process onto chemically modified biomaterials using factorial and response surface design.

    PubMed

    Gabor, Andreea; Davidescu, Corneliu Mircea; Negrea, Adina; Ciopec, Mihaela; Grozav, Ion; Negrea, Petru; Duteanu, Narcis

    2017-01-29

    The rare metals' potential to pollute air, water, soil, and especially groundwater has received lot of attention recently. One of the most common rare earth group elements, lanthanum, is used in many industrial branches, and due to its toxicity, it needs to be eliminated from all residual aqueous solutions. The goal of this study was to evaluate the control of the adsorption process for lanthanum removal from aqueous solutions, using cellulose, a known biomaterial with high adsorbent properties, cheap, and environment friendly. The cellulose was chemically modified by functionalization with sodium β-glycerophosphate. The experimental results obtained after factorial design indicate optimum adsorption parameters as pH 6, contact time 60 min, and temperature 298 K, when the equilibrium concentration of lanthanum was 250 mg L(-1), and the experimental adsorption capacity obtained was 31.58 mg g(-1). Further refinement of the optimization of the adsorption process by response surface design indicates that at pH 6 and the initial concentration of 256 mg L(-1), the adsorption capacity has maximum values between 30.87 and 36.73 mg g(-1).

  3. Nanoscopic characterization of the water vapor-salt interfacial layer reveals a unique biphasic adsorption process

    PubMed Central

    Yang, Liu; He, Jianfeng; Shen, Yi; Li, Xiaowei; Sun, Jielin; Czajkowsky, Daniel M.; Shao, Zhifeng

    2016-01-01

    Our quantitative understanding of water adsorption onto salt surfaces under ambient conditions is presently quite poor owing to the difficulties in directly characterizing this interfacial layer under these conditions. Here we determine the thickness of the interfacial layer on NaCl at different relative humidities (RH) based on a novel application of atomic force spectroscopy and capillary condensation theory. In particular, we take advantage of the microsecond-timescale of the capillary condensation process to directly resolve the magnitude of its contribution in the tip-sample interaction, from which the interfacial water thickness is determined. Further, to correlate this thickness with salt dissolution, we also measure surface conductance under similar conditions. We find that below 30% RH, there is essentially only the deposition of water molecules onto this surface, typical of conventional adsorption onto solid surfaces. However, above 30% RH, adsorption is simultaneous with the dissolution of ions, unlike conventional adsorption, leading to a rapid increase of surface conductance. Thus, water adsorption on NaCl is an unconventional biphasic process in which the interfacial layer not only exhibits quantitative differences in thickness but also qualitative differences in composition. PMID:27527905

  4. Removal of phthalates and pharmaceuticals from municipal wastewater by graphene adsorption process.

    PubMed

    Yang, Gordon C C; Tang, Pei-Ling

    2016-01-01

    In this work graphene was used for evaluation of its adsorption behavior and performance in removing phthalate esters and pharmaceuticals in municipal wastewater. Di-n-butyl phthalate (DnBP), di-(2-ethylhexyl) phthalate (DEHP), acetaminophen (ACE), caffeine (CAF), cephalexin (CLX), and sulfamethoxazole (SMX) were emerging contaminants (ECs) with detection frequencies over 92% in a one-year monitoring of the occurrence of ECs in influent samples of a sewage treatment plant in Taiwan. Thus, these ECs were selected as the target contaminants for removal by graphene adsorption process. Experimental results showed that the adsorption isotherm data were fitted well to Langmuir model equation. It was also found that the adsorption process obeyed the pseudo-second-order kinetics. A graphene dosage of 0.1 g/L and adsorption time of 12 h were found to be the optimal operating conditions for the ECs of concern in model solutions in a preliminary study. By using the determined optimal operating conditions for removal of such ECs in actual municipal wastewater, removal efficiencies for various ECs were obtained and given as follows: (1) DnBP, 89%, (2) DEHP, 86%, (3) ACE, 43%, (4) CAF, 84%, (5) CLX, 81%, and (6) SMX, 34%.

  5. A Tire-Sulfur Hybrid Adsorption Denitrification (T-SHAD) process for decentralized wastewater treatment.

    PubMed

    Krayzelova, Lucie; Lynn, Thomas J; Banihani, Qais; Bartacek, Jan; Jenicek, Pavel; Ergas, Sarina J

    2014-09-15

    Nitrogen discharges from decentralized wastewater treatment (DWT) systems contribute to surface and groundwater contamination. However, the high variability in loading rates, long idle periods and lack of regular maintenance presents a challenge for biological nitrogen removal in DWT. A Tire-Sulfur Hybrid Adsorption Denitrification (T-SHAD) process was developed that combines nitrate (NO3(-)) adsorption to scrap tire chips with sulfur-oxidizing denitrification. This allows the tire chips to adsorb NO3(-) when the influent loading exceeds the denitrification capacity of the biofilm and release it when NO3(-) loading rates are low (e.g. at night). Three waste products, scrap tire chips, elemental sulfur pellets and crushed oyster shells, were used as a medium in adsorption, leaching, microcosm and up-flow packed bed bioreactor studies of NO3(-) removal from synthetic nitrified DWT wastewater. Adsorption isotherms showed that scrap tire chips have an adsorption capacity of 0.66 g NO3(-)-N kg(-1) of scrap tires. Leaching and microcosm studies showed that scrap tires leach bioavailable organic carbon that can support mixotrophic metabolism, resulting in lower effluent SO4(2-) concentrations than sulfur oxidizing denitrification alone. In column studies, the T-SHAD process achieved high NO3(-)-N removal efficiencies under steady state (90%), variable flow (89%) and variable concentration (94%) conditions.

  6. Molecular heterogeneity of photosystem I. psaD, psaE, psaF, psaH, and psaL are all present in isoforms in Nicotiana spp.

    PubMed

    Obokata, J; Mikami, K; Hayashida, N; Nakamura, M; Sugiura, M

    1993-08-01

    The protein composition of photosystem I (PSI) was examined in Nicotiana spp. by high-resolution polyacrylamide gel electrophoresis, N-terminal amino acid sequencing, and immunoblot analysis. Five PSI proteins show polymorphism in an amphidiploid species, Nicotiana tabacum, but not in its ancestral diploid species, Nicotiana sylvestris and Nicotiana tomentosiformis. These Nicotiana spp. appear to have at least 18 PSI proteins per genome that range in molecular mass from 3 to 20 kD. They include the products of nuclear genes psaD, psaE, psaF, psaG, psaH, psaK, and psaL, the product of chloroplast gene psaC, N-terminally blocked proteins of 4.5 and 3.0 kD, and an unidentified protein of 12.5 kD. The psaD, psaF, psaH, and psaL products have two isoforms each that are distinguished by different mobilities in polyacrylamide gel electrophoresis, and the psaE product has four isoforms. The two isoforms of the psaD product have distinct amino acid sequences, indicating that they are encoded by different genes within the genome. Four isoforms of the psaE products can be classified into two groups by N-terminal amino acid sequence, indicating that at least two psaE genes are present in the genome. To examine whether the polymorphic nature of PSI is peculiar to Nicotiana spp., we carried out immunoblot analysis of the psaD and psaE products in isogenic lines of tomato (Lycopersicon esculentum), Arabidopsis thaliana, red bean (Vigna angularis), and corn (Zea mays). Two electrophoretically distinct isoforms were found for the psaD products of tomato, A. thaliana, and corn, and two isoforms of psaE products were detected in tomato, A. thaliana, and red bean. These results suggest that the nuclear-encoded subunits of PSI, except for the psaG and psaK products, generally have two isoforms.

  7. Adsorption of aluminum and lead from wastewater by chitosan-tannic acid modified biopolymers: Isotherms, kinetics, thermodynamics and process mechanism.

    PubMed

    Badawi, M A; Negm, N A; Abou Kana, M T H; Hefni, H H; Abdel Moneem, M M

    2017-06-01

    Chitosan was reacted by tannic acid to obtain three modified chitosan biopolymer. Their chemical structures were characterized by FTIR and elemental analysis. The prepared biopolymers were used to adsorb Al(III) and Pb(II) metal ions from industrial wastewater. The factors affecting the adsorption process were biosorbent amount, initial concentration of metal ion and pH of the medium. The adsorption efficiency increased considerably with the increase of the biosorbent amount and pH of the medium. The adsorption process of biosorbent on different metal ions was fitted by Freundlich adsorption model. The adsorption kinetics was followed Pseudo-second-order kinetic model. The adsorption process occurred according to diffusion mechanism which was confirmed by the interparticle diffusion model. The modified biopolymers were efficient biosorbents for removal of Pb(II) and Al(III) metal ions from the medium.

  8. Prostate-specific antigen (PSA) blood test

    MedlinePlus

    Prostate-specific antigen; Prostate cancer screening test; PSA ... special steps are needed to prepare for this test. ... Reasons for a PSA test: This test may be done to screen for prostate cancer. It is also used to follow people after prostate cancer ...

  9. Study of adsorption process of iron colloid substances on activated carbon by ultrasound

    NASA Astrophysics Data System (ADS)

    Machekhina, K. I.; Shiyan, L. N.; Yurmazova, T. A.; Voyno, D. A.

    2015-04-01

    The paper reports on the adsorption of iron colloid substances on activated carbon (PAC) Norit SA UF with using ultrasound. It is found that time of adsorption is equal to three hours. High-frequency electrical oscillation is 35 kHz. The adsorption capacity of activated carbon was determined and it is equal to about 0.25 mg iron colloid substances /mg PAC. The iron colloid substances size ranging from 30 to 360 nm was determined. The zeta potential of iron colloid substances which consists of iron (III) hydroxide, silicon compounds and natural organic substances is about (-38mV). The process of destruction iron colloid substances occurs with subsequent formation of a precipitate in the form of Fe(OH)3 as a result of the removal of organic substances from the model solution.

  10. Kinetic studies of competitive adsorption processes related to automobile catalytic converters

    SciTech Connect

    Zaera, F.; Paffett, M.T.

    1998-12-31

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The goal of this project was to study the microscopic details for the adsorption of CO, NO, and O{sub 2} on transition metal surfaces under conditions resembling those present in automobile catalytic converters. Initial sticking coefficients were measured as a function of temperature on transition metal single crystals by using a method originally developed by King and Wells. These measurements were performed under conditions emulating those typical of competitive adsorption, namely, where the substrate is exposed to a mixture of two or more gases simultaneously, or where one molecule is adsorbed on the surface prior to exposure to the second gas. The experimental results were then analyzed by using Monte Carlo computer simulation algorithm in an attempt to better understand the relevant aspects of the adsorption process.

  11. COLUMBIC OXIDE ADSORPTION PROCESS FOR SEPARATING URANIUM AND PLUTONIUM IONS

    DOEpatents

    Beaton, R.H.

    1959-07-14

    A process is described for separating plutonium ions from a solution of neutron irradiated uranium in which columbic oxide is used as an adsorbert. According to the invention the plutonium ion is selectively adsorbed by Passing a solution containing the plutonium in a valence state not higher than 4 through a porous bed or column of granules of hydrated columbic oxide. The adsorbed plutonium is then desorbed by elution with 3 N nitric acid.

  12. [Process of adsorption and separating recovery solvents from vapor mixture directly].

    PubMed

    Wang, Hong-Yu; Qiang, Ning; Hu, Xia

    2011-12-01

    Experiment on process feasibility of adsorption and separating recovery of organic compounds directly from waste gas was conducted with the activated carbon column train consists of 4 units in serial. Isopropyl alcohol and toluene vapor mixture was used as target gas, which are the common constituents of the gas emitted from fine ceramic manufacture. The experimental results showed obvious adsorption stratification phenomena alone the activated carbon column length for the vapor mixture. Under the condition of superficial gas velocity of 0.42 m x s(-1), inlet concentration of 477 mg x m(-3) and 746 mg x m(-3) for isopropyl alcohol and toluene respectively, 26 cm total carbon packing length of the four column serial train, when the adsorption time reached 798 min, the adsorption capacities for toluene and isopropyl alcohol are 184.5 mg x g(-1) and 0 mg x g(-1) respectively in 0-10 cm section, and 0.92 mg x g(-1) and 91.2 mg x g(-1) respectively in 21-26 cm section, liquids with over 99% purity of isopropyl alcohol and toluene were recovered separately from the two end columns of the carbon column train. There is a gaseous concentration amplifier zone in the carbon column for the weaker adsorbate, isopropyl alcohol, which make the adsorption capacity of isopropyl alcohol increase over 27% in part of the down flow zone in this experiment. It is possible to directly recover the pure solvent liquid separately from the vapor mixture by the way of a serial adsorption column with separating stage recovering.

  13. Petroleum coke adsorption as a water management option for oil sands process-affected water.

    PubMed

    Zubot, Warren; MacKinnon, Michael D; Chelme-Ayala, Pamela; Smith, Daniel W; Gamal El-Din, Mohamed

    2012-06-15

    Water is integral to both operational and environmental aspects of the oil sands industry. A water treatment option based on the use of petroleum coke (PC), a by-product of bitumen upgrading, was examined as an opportunity to reduce site oil sands process-affected water (OSPW) inventories and net raw water demand. Changes in OSPW quality when treated with PC included increments in pH levels and concentrations of vanadium, molybdenum, and sulphate. Constituents that decreased in concentration after PC adsorption included total acid-extractable organics (TAO), bicarbonate, calcium, barium, magnesium, and strontium. Changes in naphthenic acids (NAs) speciation were observed after PC adsorption. A battery of bioassays was used to measure the OSPW toxicity. The results indicated that untreated OSPW was toxic towards Vibrio fischeri and rainbow trout. However, OSPW treated with PC at appropriate dosages was not acutely toxic towards these test organisms. Removal of TAO was found to be an adsorption process, fitting the Langmuir and Langmuir-Freundlich isotherm models. For TAO concentrations of 60 mg/L, adsorption capacities ranged between 0.1 and 0.46 mg/g. This study demonstrates that freshly produced PC from fluid cokers provides an effective treatment of OSPW in terms of key constituents' removal and toxicity reduction.

  14. Adsorption of crystal violet with diatomite earth&carbon by a modification of hydrothermal carbonization process.

    PubMed

    Zhang, Yanzhuo; Li, Jun; Chen, Guanghui; Bian, Wei; Lu, Yun; Li, Wenjing; Zheng, Zhaoming; Cheng, Xiaojie

    2016-01-01

    The high colority and difficulty of decolorization are the most important tasks on printing and dyeing wastewater. This study investigates the ability of diatomite earth&carbon (DE&C) as an adsorbent to removal crystal violet (CV) from aqueous solutions. Fourier transform infrared spectroscopy results indicate the importance of functional groups during the adsorption of CV. The obtained N2 adsorption-desorption isotherm values accord with well IUPAC type II. Our calculations determined a surface area of 73.15 m(2) g(-1) for DE&C and an average pore diameter of 10.56 nm. Equilibrium data of the adsorption process fitted very well to the Langmuir model (R(2) > 0.99). The results of kinetics study showed that the pseudo-second-order model fitted to the experimental data well. The thermodynamic parameters were also evaluated. ΔH° <0, ΔS° > 0 and ΔG° < 0 demonstrated that the adsorption process was spontaneous and exothermic for dye. Furthermore the positive value of ΔS° reflected good affinity of the CV dye.

  15. Vaccination with agonist peptide PSA: 154-163 (155L) derived from prostate specific antigen induced CD8 T-cell response to the native peptide PSA: 154-163 but failed to induce the reactivity against tumor targets expressing PSA: a phase 2 study in patients with recurrent prostate cancer.

    PubMed

    Kouiavskaia, Diana V; Berard, Carla A; Datena, Ellen; Hussain, Arif; Dawson, Nancy; Klyushnenkova, Elena N; Alexander, Richard B

    2009-01-01

    We conducted a clinical trial of peptide prostate specific antigen (PSA): 154-163 (155L) vaccination in human leukocyte antigen (HLA)-A2 patients with detectable and rising serum PSA after radical prostatectomy for prostate cancer (Clinicaltrials.gov identifier NCT00109811). The trial was a single dose-level, phase 2 pilot trial of 1 mg of PSA: 154-163 (155L) emulsified with adjuvant (Montanide ISA-51). The primary endpoint was the determination of immunogenicity of the vaccine; secondary outcomes were determination of toxicity and effect on serum PSA. The vaccine was given subcutaneously 7 times on weeks 0, 2, 4, 6, 10, 14, and 18. Peptide-specific CD8 T-cell responses in the peripheral blood mononuclear cells (PBMC) of patients were measured by interferon (IFN)-gamma enzyme-linked immunosorbent spot assay. CD8 T-cell cultures were also established by in vitro stimulation with the peptide presented by autologous dendritic cells. Five patients were enrolled and completed all vaccinations. No IFN-gamma response to PSA: 154-163 (155L) was detected in unfractioned PBMC in any patient either before or after vaccination. Three of 5 patients demonstrated strong IFN-gamma responses to PSA: 154-163 (155L) and native PSA: 154-163 peptides in CD8 T-cell cultures derived from postvaccination PBMC. However, peptide-specific T cells failed to recognize HLA-A2 positive targets expressing endogenous PSA. There were no significant changes in serum PSA level in any subject. No serious adverse events were observed. PSA: 154-163 (155L) is not an effective immunogen when given with Montanide ISA-51. The PSA: 154-163 peptide is poorly processed from endogenous PSA and therefore represents a cryptic epitope of PSA in HLA-A2 antigen-presenting cells.

  16. GIS Technologies For The New Planetary Science Archive (PSA)

    NASA Astrophysics Data System (ADS)

    Docasal, R.; Barbarisi, I.; Rios, C.; Macfarlane, A. J.; Gonzalez, J.; Arviset, C.; De Marchi, G.; Martinez, S.; Grotheer, E.; Lim, T.; Besse, S.; Heather, D.; Fraga, D.; Barthelemy, M.

    2015-12-01

    Geographical information system (GIS) is becoming increasingly used for planetary science. GIS are computerised systems for the storage, retrieval, manipulation, analysis, and display of geographically referenced data. Some data stored in the Planetary Science Archive (PSA), for instance, a set of Mars Express/Venus Express data, have spatial metadata associated to them. To facilitate users in handling and visualising spatial data in GIS applications, the new PSA should support interoperability with interfaces implementing the standards approved by the Open Geospatial Consortium (OGC). These standards are followed in order to develop open interfaces and encodings that allow data to be exchanged with GIS Client Applications, well-known examples of which are Google Earth and NASA World Wind as well as open source tools such as Openlayers. The technology already exists within PostgreSQL databases to store searchable geometrical data in the form of the PostGIS extension. An existing open source maps server is GeoServer, an instance of which has been deployed for the new PSA, uses the OGC standards to allow, among others, the sharing, processing and editing of data and spatial data through the Web Feature Service (WFS) standard as well as serving georeferenced map images through the Web Map Service (WMS). The final goal of the new PSA, being developed by the European Space Astronomy Centre (ESAC) Science Data Centre (ESDC), is to create an archive which enables science exploitation of ESA's planetary missions datasets. This can be facilitated through the GIS framework, offering interfaces (both web GUI and scriptable APIs) that can be used more easily and scientifically by the community, and that will also enable the community to build added value services on top of the PSA.

  17. Removal of heavy metals from aqueous solution by chelating resin in a multistage adsorption process.

    PubMed

    Lin, S H; Lai, S L; Leu, H G

    2000-08-28

    Copper and zinc removal from aqueous solution by chelating resin was investigated theoretically and experimentally in the present study. A multistage process was proposed as an alternative for enhancement of the heavy removal of the single-stage process. Heavy metal mass balance equations with empirical Freundlich adsorption isotherm were developed to represent the multistage process and the theoretical model permits determination of the inter-stage heavy metal concentrations and the total amount of chelating resin required for achieving a desired level of heavy metal removal. Optimization of the linearized theoretical model shows that equal division of the total amount of chelating resin among all stages of the multistage process yields the best results in terms of saving of chelating resin for a given heavy metal removal or enhanced heavy metal removal for a given total amount of chelating resin. Experimental tests were also conducted to establish the equilibrium adsorption of heavy metal by the chelating resin and to empirically verify the advantages of the multistage adsorption process.

  18. Analysis of Scanning Electron Microscopy Images To Investigate Adsorption Processes Responsible for Detection of Cancer Biomarkers.

    PubMed

    Rodrigues, Valquiria da Cruz; Comin, Cesar H; Soares, Juliana Coatrini; Soares, Andrey Coatrini; Melendez, Matias Eliseo; Fregnani, José Humberto T G; Carvalho, André Lopes; Costa, Luciano da F; Oliveira, Osvaldo N

    2017-02-22

    Adsorption processes are responsible for detection of cancer biomarkers in biosensors (and immunosensors), which can be captured with various principles of detection. In this study, we used a biosensor made with nanostructured films of polypyrrole and p53 antibodies, and image analysis of scanning electron microscopy data made it possible to correlate morphological changes of the biosensor with the concentration of cells containing the cancer biomarker p53. The selectivity of the biosensor was proven by distinguishing images obtained with exposure of the biosensor to cells containing the biomarker from those acquired with cells that did not contain it. Detection was confirmed with cyclic voltammetry measurements, while the adsorption of the p53 biomarker was probed with polarization-modulated infrared reflection absorption (PM-IRRAS) and a quartz crystal microbalance (QCM). Adsorption is described using the Langmuir-Freundlich model, with saturation taking place at a concentration of 100 Ucells/mL. Taken together, our results point to novel ways to detect biomarkers or any type of analyte for which detection is based on adsorption as is the case of the majority of biosensors.

  19. Comparative evaluation of cyanide removal by adsorption, biodegradation, and simultaneous adsorption and biodegradation (SAB) process using Bacillus cereus and almond shell.

    PubMed

    Dwivedi, Naveen; Balomajumder, Chandrajit; Mondal, Prasenji

    2016-07-01

    The present study aimed to investigate the removal efficiency of cyanide from contaminated water by adsorption, biodegradation and simultaneous adsorption and biodegradation (SAB) process individually in a batch reactor. Adsorption was achieved by using almond shell granules and biodegradation was conducted with suspended cultures of Bacillus cereus, whereas SAB process was carried out using Bacillus cereus and almond shell in a batch reactor. The effect of agitation time, pH, and initial cyanide concentration on the % removal of cyanide has been discussed. Under experimental conditions, optimum removal was obtained at pH 7 with agitation time of 48 hrs and temperature of 35 degrees C. Cyanide was utilized by bacteria as sole source of nitrogen for growth. The removal efficiencies of cyanide by adsorption, biodegradation, and SAB were found to be 91.38%, 95.87%, and 99.63%, respectively, at initial cyanide concentration of 100 mg l(-1). The removal efficiency of SAB was found to be better as compared to that of biodegradation and adsorption alone.

  20. Separation of lignocelluloses from spent liquor of NSSC pulping process via adsorption.

    PubMed

    Dashtban, Mehdi; Gilbert, Allan; Fatehi, Pedram

    2014-04-01

    Hemicelluloses and lignin present in the spent liquor (SL) of neutral sulfite semichemical (NSSC) pulping process can potentially be converted into value-added products such as furfural, hydroxymethylfurfural, levulinic acid, phenols and adhesives. However, the direct conversion of hemicelluloses and lignin of SL into value-added products is uneconomical due to the dilute nature of the SL. To have a feasible downstream process for utilizing lignocelluloses of SL, the lignocelluloses should initially be separated from the SL. In this study, an adsorption process (via applying activated carbon) was considered for isolating the dissolved lignin and hemicelluloses from the SL of an NSSC pulping process. Under the optimal conditions of pH, SL/AC weight ratio, time and temperature of 5.7, 30, 360 min and 30 °C, the maximum lignin and hemicellulose adsorptions were 0.33 and 0.25 g/g on AC. The chemical oxygen demand (COD) and turbidity of the SL were decreased by 11% and 39%, respectively, as a result of lignocellulose adsorption on AC. Also, the incineration behavior of the SL-treated AC was studied with a thermo-gravimetric analysis (TGA).

  1. Advancing adsorption and membrane separation processes for the gigaton carbon capture challenge.

    PubMed

    Wilcox, Jennifer; Haghpanah, Reza; Rupp, Erik C; He, Jiajun; Lee, Kyoungjin

    2014-01-01

    Reducing CO2 in the atmosphere and preventing its release from point-source emitters, such as coal and natural gas-fired power plants, is a global challenge measured in gigatons. Capturing CO2 at this scale will require a portfolio of gas-separation technologies to be applied over a range of applications in which the gas mixtures and operating conditions will vary. Chemical scrubbing using absorption is the current state-of-the-art technology. Considerably less attention has been given to other gas-separation technologies, including adsorption and membranes. It will take a range of creative solutions to reduce CO2 at scale, thereby slowing global warming and minimizing its potential negative environmental impacts. This review focuses on the current challenges of adsorption and membrane-separation processes. Technological advancement of these processes will lead to reduced cost, which will enable subsequent adoption for practical scaled-up application.

  2. Modelling GAC adsorption of biologically pre-treated process water from hydrothermal carbonization.

    PubMed

    Fettig, J; Liebe, H

    2015-01-01

    Granular-activated carbon (GAC) adsorption of biologically pre-treated process waters from hydrothermal carbonization (HTC) of different materials was investigated. Overall, isotherms showed that most of the dissolved organic substances are strongly adsorbable while the non-adsorbable fractions are small. The equilibrium data were modelled by using five fictive components to represent the organic matter. Mean film transfer coefficients and mean intraparticle diffusivities were derived from short-column and batch kinetic test data, respectively. Breakthrough curves in GAC columns could be predicted satisfactorily by applying the film-homogeneous diffusion model and using the equilibrium and kinetic parameters determined from batch tests. Thus, the approach is suited to model GAC adsorption of HTC process water under technical-scale conditions.

  3. The ESA Planetary Science Archive User Group (PSA-UG)

    NASA Astrophysics Data System (ADS)

    Pio Rossi, Angelo; Cecconi, Baptiste; Fraenz, Markus; Hagermann, Axel; Heather, David; Rosenblatt, Pascal; Svedhem, Hakan; Widemann, Thomas

    2014-05-01

    ESA has established a Planetary Science Archive User Group (PSA-UG), with the task of offering independent advice to ESA's Planetary Science Archive (e.g. Heather et al., 2013). The PSA-UG is an official and independent body that continuously evaluates services and tools provided by the PSA to the community of planetary data scientific users. The group has been tasked with the following top level objectives: a) Advise ESA on future development of the PSA. b) Act as a focus for the interests of the scientific community. c) Act as an advocate for the PSA. d) Monitor the PSA activities. Based on this, the PSA-UG will report through the official ESA channels. Disciplines and subjects represented by PSA-UG members include: Remote Sensing of both Atmosphere and Solid Surfaces, Magnetospheres, Plasmas, Radio Science and Auxilliary data. The composition of the group covers ESA missions populating the PSA both now and in the near future. The first members of the PSA-UG were selected in 2013 and will serve for 3 years, until 2016. The PSA-UG will address the community through workshops, conferences and the internet. Written recommendations will be made to the PSA coordinator, and an annual report on PSA and the PSA-UG activities will be sent to the Solar System Exploration Working Group (SSEWG). Any member of the community and planetary data user can get in touch with individual members of the PSA-UG or with the group as a whole via the contacts provided on the official PSA-UG web-page: http://archives.esac.esa.int/psa/psa-ug. The PSA is accessible via: http://archives.esac.esa.int/psa References: Heather, D., Barthelemy, M., Manaud, N., Martinez, S., Szumlas, M., Vazquez, J. L., Osuna, P. and the PSA Development Team (2013) ESA's Planetary Science Archive: Status, Activities and Plans. EuroPlanet Sci. Congr. #EPSC2013-626

  4. PSA Isoforms' Velocities for Early Diagnosis of Prostate Cancer.

    PubMed

    Heidegger, Isabel; Klocker, Helmut; Pichler, Renate; Horninger, Wolfgang; Bektic, Jasmin

    2015-06-01

    Free prostate-specific antigen (fPSA) and its molecular isoforms are suggested for enhancement of PSA testing in prostate cancer (PCa). In the present study we evaluated whether PSA isoforms' velocities might serve as a tool to improve early PCa diagnosis. Our study population included 381 men who had undergone at least one ultrasound-guided prostate biopsy whose pathologic examination yielded PCa or showed no evidence of prostatic malignancy. Serial PSA, fPSA, and proPSA measurements were performed on serum samples covering 7 years prior to biopsy using Beckmann Coulter Access immunoassays. Afterwards, velocities of PSA (PSAV), fPSA% (fPSA%V), proPSA% (proPSA%V) and the ratio proPSA/PSA/V were calculated and their ability to discriminate cancer from benign disease was evaluated. Among 381 men included in the study, 202 (53%) were diagnosed with PCa and underwent radical prostatectomy at our Department. PSAV, fPSA%V, proPSA%V as well as proPSA/PSA/V were able to differentiate significantly between PCa and non-cancerous prostate. The highest discriminatory power between cancer and benign disease has been observed two and one year prior to diagnosis with all measured parameters. Among all measured parameters, fPSA%V showed the best cancer specificity of 45.3% with 90% of sensitivity. In summary, our results highlight the value of PSA isoforms' velocity for early detection of PCa. Especially fPSA%V should be used in the clinical setting to increase cancer detection specificity.

  5. The ESA Planetary Science Archive User Group (PSA-UG)

    NASA Astrophysics Data System (ADS)

    Rossi, A. P.; Cecconi, B.; Fraenz, M.; Hagermann, A.; Heather, D.; Rosenblatt, P.; Svedhem, H.; Widemann, T.

    2014-04-01

    ESA has established a Planetary Science Archive User Group (PSA-UG), with the task of offering independent advice to ESA's Planetary Science Archive (e.g. Heather et al., 2013). The PSA-UG is an official and independent body that continuously evaluates services and tools provided by the PSA to the community of planetary data scientific users. The group has been tasked with the following top level objectives: a) Advise ESA on future development of the PSA. b) Act as a focus for the interests of the scientific community. c) Act as an advocate for the PSA. d) Monitor the PSA activities. Based on this, the PSA-UG will report through the official ESA channels. Disciplines and subjects represented by PSA-UG members include: Remote Sensing of both Atmosphere and Solid Surfaces, Magnetospheres, Plasmas, Radio Science and Auxilliary data. The composition of the group covers ESA missions populating the PSA both now and in the near future. The first members of the PSA-UG were selected in 2013 and will serve for 3 years, until 2016. The PSA-UG will address the community through workshops, conferences and the internet. Written recommendations will be made to the PSA coordinator, and an annual report on PSA and the PSA-UG activities will be sent to the Solar System Exploration Working Group (SSEWG). Any member of the community and planetary data user can get in touch with individual members of the PSA-UG or with the group as a whole via the contacts provided on the official PSA-UG web-page: http://archives.esac.esa.int/psa/psa-ug The PSA is accessible via: http://archives.esac.esa.int/psa

  6. A Multi-Center Study of [−2]Pro-Prostate-Specific Antigen (PSA) in Combination with PSA and Free PSA for Prostate Cancer Detection in the 2.0 to 10.0 ng/mL PSA Range

    PubMed Central

    Catalona, William J.; Partin, Alan W.; Sanda, Martin G.; Wei, John T.; Klee, George G.; Bangma, Chris H.; Slawin, Kevin M.; Marks, Leonard S.; Loeb, Stacy; Broyles, Dennis L.; Shin, Sanghyuk S.; Cruz, Amabelle B.; Chan, Daniel W.; Sokoll, Lori J.; Roberts, William L.; van Schaik, Ron H.N.; Mizrahi, Isaac A.

    2011-01-01

    Purpose PSA and free PSA (fPSA) have limited specificity for detecting clinically significant, curable prostate cancer (PCa), leading to unnecessary biopsies and detection and treatment of some indolent tumors. [−2]proPSA (p2PSA) may improve specificity for detecting clinically significant PCa. Our objective was to evaluate p2PSA, fPSA, and PSA in a mathematical formula (prostate health index [phi] = [−2]proPSA / fPSA) × PSA1/2) to enhance specificity for detecting overall and high-grade PCa. Materials and Methods We enrolled 892 men in a prospective multi-institutional trial with no history of PCa, normal rectal examination, a PSA of 2–10 ng/mL, and ≥6- core prostate biopsy. We examined the relationship of serum PSA, %fPSA and phi with biopsy results. The primary endpoints were the specificity and AUC using phi to detect overall and Gleason ≥7 prostate cancer on biopsy compared with %fPSA. Results For the 2–10 ng/mL PSA range, at 80–95% sensitivity, the specificity and AUC (0.703) of phi exceeded those of PSA and %fPSA. Increasing phi was associated with a 4.7-fold increased risk of PCa and 1.61-fold increased risk of Gleason ≥7 disease on biopsy. The AUC for phi (0.724) exceeded that of %fPSA (0.670) in discriminating between PCa with Gleason ≥ 4+3 vs. lower grade disease or negative biopsies. Phi results were not associated with age and prostate volume. Conclusions Phi may be useful in PCa screening to reduce unnecessary biopsies in men age ≥50 years with PSA 2–10 ng/mL and negative DRE, with minimal loss in sensitivity. PMID:21419439

  7. Research of combined adsorption-coagulation process in treating petroleum refinery effluent.

    PubMed

    Wang, Bing; Shui, Yiyu; Ren, Hongyang; He, Min

    2017-02-01

    The petroleum refinery industry generates a significant amount of wastewater that contains a high level of organic matter, which calls for effective and costly treatments. In this research, the effectiveness of the petroleum refinery effluent (PRE) treatment with physicochemical process of combined adsorption and coagulation was evaluated. The effects of initial pH, hydraulic condition , and combined sequence of treatment process, different treating reagent types and dosages on the chemical oxygen demand (COD) removal were investigated. Additionally, the elimination efficiency of pollutant wastewater was monitored by gas chromatography-mass spectrometry (GC-MS), and Fourier transformed infrared (FT-IR) spectrophotometer was adopted to describe the structure of the wastewater. Wooden activated carbon was chosen as adsorbent at the dosage of 10 g/L as a primary treatment, and 1500 mg/L polymeric magnesium ferric sulfate was used in coagulation. Results showed that adsorption and subsequent coagulation displayed the best performance when initial pH was 9 at shear rates (G) of G1 = 65 s(-1) and G2 = 20 s(-1), which reached maximal removal rate of COD and total organic carbon GC-MS testing result revealed that adsorption was effective in phenols and iso-alkanes removal, whereas coagulation was good at removing esters and n-alkanes.

  8. Hybrid membrane--PSA system for separating oxygen from air

    DOEpatents

    Staiger, Chad L [Albuquerque, NM; Vaughn, Mark R [Albuquerque, NM; Miller, A Keith [Albuquerque, NM; Cornelius, Christopher J [Blackburg, VA

    2011-01-25

    A portable, non-cryogenic, oxygen generation system capable of delivering oxygen gas at purities greater than 98% and flow rates of 15 L/min or more is described. The system consists of two major components. The first component is a high efficiency membrane capable of separating argon and a portion of the nitrogen content from air, yielding an oxygen-enriched permeate flow. This is then fed to the second component, a pressure swing adsorption (PSA) unit utilizing a commercially available, but specifically formulated zeolite compound to remove the remainder of the nitrogen from the flow. The system is a unique gas separation system that can operate at ambient temperatures, for producing high purity oxygen for various applications (medical, refining, chemical production, enhanced combustion, fuel cells, etc . . . ) and represents a significant advance compared to current technologies.

  9. The DeNOx process and NO2 adsorption in MOF74

    NASA Astrophysics Data System (ADS)

    Zuluaga, S.; Thonhauser, T.; Tan, K.; Chabal, Y.

    2014-03-01

    Due to the harmful character of NO2 and its slow decomposition rate, the use of catalytic materials for its removal (DeNOx process) has attracted a lot of attention. The high porosity and highly reactive uncoordinated metal centers of MOF74 have led us to investigate the use of Mg- and Zn-MOF74 as materials for trapping NO2 with resistance to poisoning by SO2. In this combined theoretical and experimental study, we investigate the interaction between the unsaturated metal centers of the MOF and the NO2 guest molecules. For our theoretical modeling we use ab initio calculations at the DFT level, utilizing vdW-DF to capture the significant van der Waals component of the interaction between NO2 and the MOF. We present detailed first-principle results concerning the adsorption energies and geometries, as well as vibration frequencies of the NO2 molecule adsorbed in the MOF. Our experimental efforts (IR and Raman spectroscopy) have shown a blue shift to 1684 cm-1 in the vibration stretching mode of the NO2 upon adsorption and a thermal stability up to 150°C. Our first-principle calculations and experimental results show a remarkable agreement, allowing us to give a complete picture of the adsorption of NO2 molecules in the MOF74 structure. Supported by DOE DE-FG02-08ER46491.

  10. Crude clove bud oil (CBO) quality improvement by bentonite adsorption process in flow system

    NASA Astrophysics Data System (ADS)

    Rubiyanto, Dwiarso; Diaty, Dita; Allwar

    2017-03-01

    Improvement of the quality of crude clove bud oil (crude CBO) by bentonite adsorption process in flow system had been done. This research aimed to improve the quality of crude CBO based on SNI 06-4267-1996 and SNI 06-2387-2006. The parameters were colours, densities, refractives index, eugenol and trans-caryophillene contents and also the additional analysis parameter which were the analysis of Fe using bentonite and measurement of pH using universal paper. Adsorption was carried out in the optimation of bentonite. The weight variations of bentonite was 5, 10, 15 and 20 grams. From the surface area analysis, it showed that bentonite had surface area about 30,512 m2/g which was activated chemically using 0,5 M HCl and calcinated using furnace in temperature of 400 0C. The results showed that the analysis of colours, densities, recfractives index and test of pH were not different significantly. Meanwhile the adsorption of Fe metal using 20 gram bentonite be able to adsorp until 94,20%. The highest percentage of eugenol found in the variation of 5 gram which was about 13,52% and decreased trans-caryophillene in 9,64% of 15 gram bentonite.

  11. Analysis of the adsorption process and of desiccant cooling systems: a pseudo- steady-state model for coupled heat and mass transfer. [DESSIM, DESSIM2, DESSIM4

    SciTech Connect

    Barlow, R.S.

    1982-12-01

    A computer model to simulate the adiabatic adsorption/desorption process is documented. Developed to predict the performance of desiccant cooling systems, the model has been validated through comparison with experimental data for single-blow adsorption and desorption. A literature review on adsorption analysis, detailed discussions of the adsorption process, and an initial assessment of the potential for performance improvement through advanced component development are included.

  12. An integrated expanded bed adsorption process for lactoferrin and immunoglobulin G purification from crude sweet whey.

    PubMed

    Du, Qiao-Yan; Lin, Dong-Qiang; Zhang, Qi-Lei; Yao, Shan-Jing

    2014-02-01

    An integrated expanded bed adsorption process was developed in this study to purify lactoferrin and immunoglobulin G (IgG) from crude sweet whey. The process used two sequential expanded beds packed with a cationic exchanger (Fastline SP) and a mixed-mode resin (Streamline Direct CST-1), respectively. Lactoferrin was isolated in the first expanded bed packed with Fastline SP, and the flow through was loaded into the second expanded bed packed with Streamline Direct CST-1 to separate IgG. Three integration strategies were compared to improve the separation efficiency, especially for the purification of IgG in the second expanded bed. The purities of IgG obtained from these three strategies were 91.9%, 83.8% and 92.4%, and the recoveries were 14.3%, 63.7% and 29.7%, respectively. By efficient integration of the two expanded beds, lactoferrin and IgG were successfully recovered from crude sweet whey with high purities and reasonable recoveries. Moreover, the stream flowed out of the integrated process was collected and separated by ultrafiltration to produce whey protein concentrate. Therefore, sweet whey resource could be fully utilized. The results demonstrated that it is possible to purify multiple proteins from untreated crude resource with a rationally designed expanded bed adsorption process.

  13. Comparison of adsorption and photo-Fenton processes for phenol and paracetamol removing from aqueous solutions: single and binary systems.

    PubMed

    Rad, Leila Roshanfekr; Haririan, Ismaeil; Divsar, Faten

    2015-02-05

    In the present study, adsorption and photo-Fenton processes have been compared for the removal of phenol and paracetamol from aqueous solutions in a single and binary systems. NaX nanozeolites and cobalt ferrite nanoparticles were used during adsorption and photo-Fenton processes, respectively. Both nanoparticles were synthesized using microwave heating method. The synthesized nanoparticles were characterized using powder X-ray diffraction (XRD) and scanning electronic microscopy (SEM) analysis. Based on results, more than 99% removing percentages of phenol and paracetamol were obtained during photo-Fenton process at initial concentrations of 10, 20, 50, 100 and 200 mg/L of phenol and paracetamol. Moreover, the complete removing of phenol and paracetamol was only achieved at lower initial concentrations than 10 mg/L for phenol and paracetamol during adsorption process. The results showed a significant dependence of the phenol and paracetamol removing on the initial concentrations of phenol and paracetamol for selection of process. The photo-Fenton process could be considered an alternative method in higher initial concentrations of phenol and paracetamol. However, the adsorption process due to economical issue was preferred for phenol and paracetamol removing at lower initial concentrations. The kinetic data of photo-Fenton and adsorption processes were well described using first-order and pseudo-second-order kinetic models. The results of phenol and paracetamol removing in a binary system confirmed the obtained results of single removing of phenol and paracetamol in selection of process.

  14. Comparison of adsorption and photo-Fenton processes for phenol and paracetamol removing from aqueous solutions: Single and binary systems

    NASA Astrophysics Data System (ADS)

    Rad, Leila Roshanfekr; Haririan, Ismaeil; Divsar, Faten

    2015-02-01

    In the present study, adsorption and photo-Fenton processes have been compared for the removal of phenol and paracetamol from aqueous solutions in a single and binary systems. NaX nanozeolites and cobalt ferrite nanoparticles were used during adsorption and photo-Fenton processes, respectively. Both nanoparticles were synthesized using microwave heating method. The synthesized nanoparticles were characterized using powder X-ray diffraction (XRD) and scanning electronic microscopy (SEM) analysis. Based on results, more than 99% removing percentages of phenol and paracetamol were obtained during photo-Fenton process at initial concentrations of 10, 20, 50, 100 and 200 mg/L of phenol and paracetamol. Moreover, the complete removing of phenol and paracetamol was only achieved at lower initial concentrations than 10 mg/L for phenol and paracetamol during adsorption process. The results showed a significant dependence of the phenol and paracetamol removing on the initial concentrations of phenol and paracetamol for selection of process. The photo-Fenton process could be considered an alternative method in higher initial concentrations of phenol and paracetamol. However, the adsorption process due to economical issue was preferred for phenol and paracetamol removing at lower initial concentrations. The kinetic data of photo-Fenton and adsorption processes were well described using first-order and pseudo-second-order kinetic models. The results of phenol and paracetamol removing in a binary system confirmed the obtained results of single removing of phenol and paracetamol in selection of process.

  15. Preparation of H2TiO3-lithium adsorbent by the sol-gel process and its adsorption performance

    NASA Astrophysics Data System (ADS)

    Zhang, Liyuan; Zhou, Dali; Yao, Qianqian; Zhou, Jiabei

    2016-04-01

    CH3COOLi and Ti(OC4H9)4 were employed as lithium and titanium sources, respectively to synthesize Li2TiO3 by the sol-gel process, followed by treating with hydrochloric acid to yield H2TiO3-lithium adsorbent. Various concentrations of LiOH and lithium sources were used as adsorption liquid to carry out adsorption experiment, the data from which were analyzed by Langmuir and Freundlich models. The results indicate that the optimal calcination temperature is 650 °C, and Li2TiO3 with particle size 60-80 nm is observed. The Li+ drawn out ratio from Li2TiO3 reaches 78.9%, and the dissolution of titanium ions can be as low as 0.07%. The protonated sample obtained has a lower basal spacing, while the crystal morphology is retained. The main factors affecting the adsorptive capacity are the Li+ concentration and pH in the liquid. The adsorption process of H2TiO3-lithium adsorbent can be seen as a process including surface adsorption and ion exchange. Compared with Langmuir model, Freundlich model is more suitable for describing the actual adsorption process.

  16. Optimisation of process parameters for adsorption of metal ions on straw carbon by using response surface methodology.

    PubMed

    Kannan, N; Rajakumar, A; Rengasamy, G

    2004-05-01

    Optimisation of process parameters for adsorption of metal ions viz., Cu2+, Cd2+ and Ni2+ ions on Straw Carbon (SC) was carried out by using Box-Behnken statistics and analysis of variance methods. Response surface methodology with three levels of initial pH (4, 5, 6), dose (8, 10, 12 gl(-1)) and particle size (0.075, 0.090, 0.106m micron) were used in the identification of significance of the effects and interactions in adsorption studies. Response surface methodology requires no assumption and identifies the principal experimental variables and their interactions which have the greatest effect on adsorption. The optimum process parameters for maximum adsorption of Ni2+, Cu2+ and Cd2+ were obtained by this procedure.

  17. Bayer Immuno 1 PSA Assay: an automated, ultrasensitive method to quantitate total PSA in serum.

    PubMed

    Morris, D L; Dillon, P W; Very, D L; Ng, P; Kish, L; Goldblatt, J L; Bruzek, D J; Chan, D W; Ahmed, M S; Witek, D; Fritsche, H A; Smith, C; Schwartz, D; Schwartz, M K; Noteboom, J L; Vessella, R L; Yeung, K K; Allard, W J

    1998-01-01

    The Bayer Immuno 1 PSA Assay measures total PSA in human serum and demonstrates excellent performance with an interassay CV < or = 3.4% and a biological detection limit of 0.03 microgram/L. No significant interference from common hormonal and chemotherapeutic drugs, kallikrein, prostatic acid phosphatase, and trypsin, or elevated levels of total bilirubin, hemoglobin, triglycerides, and IgG was observed. The 95th percentile values for healthy individuals increased with age from 3.0 micrograms/L for males 50-59 years and 3.3 micrograms/L for males 60-69 years, to 4.6 micrograms/L for males > or = 70 years. Clinical studies with retrospective samples demonstrated correspondence between serial measurements of PSA and clinical outcome for 98% of 159 prostate cancer patients. Clinical sensitivity for patients with clinical evidence of disease, untreated at the time of specimen draw, increased with increasing stage from 77.5-100%. Specificity of 60-70% for BPH and other benign urogenital diseases was consistent with previous findings. Bayer Immuno 1 PSA Assay values for 2131 specimens from healthy subjects and patients with prostate cancer, BPH, and other malignant and nonmalignant diseases correlated well with the Abbott IMx PSA Assay over the range 0.0-6,238 micrograms/L (Y = 1.10 x + 0.02). The Bayer Immuno 1 PSA Assay provides automated ultrasensitive, precise, and equimolar measurement of total PSA in human serum.

  18. Experimental determination of barium isotope fractionation during diffusion and adsorption processes at low temperatures

    NASA Astrophysics Data System (ADS)

    van Zuilen, Kirsten; Müller, Thomas; Nägler, Thomas F.; Dietzel, Martin; Küsters, Tim

    2016-08-01

    Variations in barium (Ba) stable isotope abundances measured in low and high temperature environments have recently received increasing attention. The actual processes controlling Ba isotope fractionation, however, remain mostly elusive. In this study, we present the first experimental approach to quantify the contribution of diffusion and adsorption on mass-dependent Ba isotope fractionation during transport of aqueous Ba2+ ions through a porous medium. Experiments have been carried out in which a BaCl2 solution of known isotopic composition diffused through u-shaped glass tubes filled with silica hydrogel at 10 °C and 25 °C for up to 201 days. The diffused Ba was highly fractionated by up to -2.15‰ in δ137/134Ba, despite the low relative difference in atomic mass. The time-dependent isotope fractionation can be successfully reproduced by a diffusive transport model accounting for mass-dependent differences in the effective diffusivities of the Ba isotope species (D137Ba /D134Ba =(m134 /m137) β). Values of β extracted from the transport model were in the range of 0.010-0.011. Independently conducted batch experiments revealed that adsorption of Ba onto the surface of silica hydrogel favoured the heavier Ba isotopes (α = 1.00015 ± 0.00008). The contribution of adsorption on the overall isotope fractionation in the diffusion experiments, however, was found to be small. Our results contribute to the understanding of Ba isotope fractionation processes, which is crucial for interpreting natural isotope variations and the assessment of Ba isotope ratios as geochemical proxies.

  19. Fabrication of carbon/SiO2 composites from the hydrothermal carbonization process of polysaccharide and their adsorption performance.

    PubMed

    Li, Yinhui; Li, Kunyu; Su, Min; Ren, Yanmei; Li, Ying; Chen, Jianxin; Li, Liang

    2016-11-20

    In this work, carbon/SiO2 composites, using amylose and tetraethyl orthosilicate (TEOS) as raw materials, were successfully prepared by a facial hydrothermal carbonization process. The carbon/SiO2 composites were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Energy Dispersive Spectroscopy (EDS), transmission electron microscope (TEM), N2 adsorption and Thermogravimetric (TG) analysis. The composites, which were made up of amorphous SiO2 and amorphous carbon, were found to have hierarchical porous structures. The mass ratios of amylose and SiO2 and the hydrothermal carbonization time had significant effects on the morphology of the composites, which had three shapes including monodispersed spheres, porous pieces and the nano-fibers combined with nano-spheres structures. The adsorption performance of the composites was studied using Pb(2+) as simulated contaminants from water. When the mass ratio of amylose and SiO2 was 9/1, the hydrothermal time was 30h and the hydrothermal temperature was 180°C, the adsorption capacity of the composites achieved to 52mg/g. Experimental data show that adsorption kinetics of the carbon/SiO2 composites can be fitted well by the Elovich model, while the isothermal data can be perfectly described by the Langmuir adsorption model and Freundlich adsorption model. The maximum adsorption capacity of the carbon/SiO2 composites is 56.18mgg(-1).

  20. Preparation and Characterization of Chitosan/Feldspar Biohybrid as an Adsorbent: Optimization of Adsorption Process via Response Surface Modeling

    PubMed Central

    Yazdani, Maryam; Bahrami, Hajir; Arami, Mokhtar

    2014-01-01

    Chitosan/feldspar biobased beads were synthesized, characterized, and tested for the removal of Acid Black 1 dye from aquatic phases. A four-factor central composite design (CCD) accompanied by response surface modeling (RSM) and optimization was used to optimize the dye adsorption by the adsorbent (chitosan/feldspar composite) in 31 different batch experiments. Independent variables of temperature, pH, initial dye concentration, and adsorbent dose were used to change to coded values. To anticipate the responses, a quadratic model was applied. Analysis of variance (ANOVA) tested the significance of the process factors and their interactions. The adequacy of the model was investigated by the correlation between experimental and predicted data of the adsorption and the calculation of prediction errors. The results showed that the predicted maximum adsorption amount of 21.63 mg/g under the optimum conditions (pH 3, temperature 15°C, initial dye concentration 125 mg/L, and dose 0.2 g/50 mL) was close to the experimental value of 19.85 mg/g. In addition, the results of adsorption behaviors of the dye illustrated that the adsorption process followed the Langmuir isotherm model and the pseudo-second-order kinetic model. Langmuir sorption capacity was found to be 17.86 mg/g. Besides, thermodynamic parameters were evaluated and revealed that the adsorption process was exothermic and favourable. PMID:24587722

  1. Methylene blue adsorption by algal biomass based materials: biosorbents characterization and process behaviour.

    PubMed

    Vilar, Vítor J P; Botelho, Cidália M S; Boaventura, Rui A R

    2007-08-17

    Dead algal biomass is a natural material that serves as a basis for developing a new family of sorbent materials potentially suitable for many industrial applications. In this work an algal industrial waste from agar extraction process, algae Gelidium and a composite material obtained by immobilization of the algal waste with polyacrylonitrile (PAN) were physical characterized and used as biosorbents for dyes removal using methylene blue as model. The apparent and real densities and the porosity of biosorbents particles were determined by mercury porosimetry and helium picnometry. The methylene blue adsorption in the liquid phase was the method chosen to calculate the specific surface area of biosorbent particles as it seems to reproduce better the surface area accessible to metal ions in the biosorption process than the N2 adsorption-desorption dry method. The porous texture of the biosorbents particles was also studied. Equilibrium isotherms are well described by the Langmuir equation, giving maximum uptake capacities of 171, 104 and 74 mg g(-1), respectively for algae, algal waste and composite material. Kinetic experiments at different initial methylene blue concentrations were performed to evaluate the equilibrium time and the importance of the driving force to overcome mass transfer resistances. The pseudo-first-order and pseudo-second-order kinetic models adequately describe the kinetic data. The biosorbents used in this work proved to be promising materials for removing methylene blue from aqueous solutions.

  2. Old landfill leachate treatment through multistage process: membrane adsorption bioreactor and nanofitration.

    PubMed

    Peyravi, Majid; Jahanshahi, Mohsen; Alimoradi, Mahsa; Ganjian, Etesam

    2016-12-01

    A bench-scale integrated process based on submerged aerobic powdered activated carbon-membrane bioreactor (PAC-MBR) has been utilized and established for the treatment of landfill leachate. The results showed that the submerged PAC-MBR system effectively removed biodegradable trace organic compounds by the average removal rate about 71 % at optimum food to microorganism (F/M) ratio of 0.4 gCOD/g day under a HRT of 24 h. Adding nanofiltration (NF) process increased the treatment efficiency up to 99 %. Further, adding powdered activated carbon to activated sludge (AS) resulted in a higher adsorption capacity in comparison with AS. Adsorption isotherms were investigated and fitted by the Langmuir and Freundlich isotherm models in which the Langmuir model performed better. The specific oxygen uptake rate (SOUR) showed that adding PAC reduces the effects of COD on microorganism activities. NH3-N, TKN and Heavy metals removal efficiency amounted to 97 ± 2, 96 ± 2, and 99 ± 2 %, respectively.

  3. Extended random sequential adsorption model of irreversible deposition processes: From simulations to experiments

    PubMed Central

    Lavalle, P.; Schaaf, P.; Ostafin, M.; Voegel, J.-C.; Senger, B.

    1999-01-01

    An experimental study of the irreversible deposition of colloidal particles of various radii R on a solid surface is presented over a wide range of the Péclet number, Pe, or reduced radius R* (Pe = R*4). The experimental data are analyzed by means of a new generalized random sequential adsorption model that takes explicitly the diffusion of the particles during the deposition into account. It allows description of the continuous transition from a random sequential adsorption-like to a ballistic-like deposition behavior. It depends on three parameters: ds, related to the diffusion of the particles before adhesion; ns, related to the number of allowed adhesion trials of a particle; and Re, representing the effective particle radius. The model allows accounting for all of the experimental observations relative to the radial distribution functions and the number density fluctuations over the whole coverage range and all investigated values of R*. In addition, it is found that ds/R is proportional to R*−2 as expected for a diffusional process. Moreover, the parameters ds and ns appear to be connected through the empirical relation (ds/R)ns2/3 = C, where C is found to be of the order of 50. This unique statistical model allows an accurate description of the irreversible deposition process, whatever the influence of gravity with respect to diffusion. PMID:10500136

  4. An explanation for differences in the process of colloid adsorption in batch and column studies

    NASA Astrophysics Data System (ADS)

    Treumann, Svantje; Torkzaban, Saeed; Bradford, Scott A.; Visalakshan, Rahul M.; Page, Declan

    2014-08-01

    It is essential to understand the mechanisms that control virus and bacteria removal in the subsurface environment to assess the risk of groundwater contamination with fecal microorganisms. This study was conducted to explicitly provide a critical and systematic comparison between batch and column experiments. The aim was to investigate the underlying factors causing the commonly observed discrepancies in colloid adsorption process in column and batch systems. We examined the colloid adsorption behavior of four different sizes of carboxylate-modified latex (CML) microspheres, as surrogates for viruses and bacteria, on quartz sand in batch and column experiments over a wide range of solution ionic strengths (IS). Our results show that adsorption of colloids in batch systems should be considered as an irreversible attachment because the attachment/detachment model was found to be inadequate in describing the batch results. An irreversible attachment-blocking model was found to accurately describe the results of both batch and column experiments. The rate of attachment was found to depend highly on colloid size, solution IS and the fraction of the sand surface area favorable for attachment (Sf). The rate of attachment and Sf values were different in batch and column experiments due to differences in the hydrodynamic of the system, and the role of surface roughness and pore structure on colloid attachment. Results from column and batch experiments were generally not comparable, especially for larger colloids (≥ 0.5 μm). Predictions based on classical DLVO theory were found to inadequately describe interaction energies between colloids and sand surfaces.

  5. An explanation for differences in the process of colloid adsorption in batch and column studies.

    PubMed

    Treumann, Svantje; Torkzaban, Saeed; Bradford, Scott A; Visalakshan, Rahul M; Page, Declan

    2014-08-01

    It is essential to understand the mechanisms that control virus and bacteria removal in the subsurface environment to assess the risk of groundwater contamination with fecal microorganisms. This study was conducted to explicitly provide a critical and systematic comparison between batch and column experiments. The aim was to investigate the underlying factors causing the commonly observed discrepancies in colloid adsorption process in column and batch systems. We examined the colloid adsorption behavior of four different sizes of carboxylate-modified latex (CML) microspheres, as surrogates for viruses and bacteria, on quartz sand in batch and column experiments over a wide range of solution ionic strengths (IS). Our results show that adsorption of colloids in batch systems should be considered as an irreversible attachment because the attachment/detachment model was found to be inadequate in describing the batch results. An irreversible attachment-blocking model was found to accurately describe the results of both batch and column experiments. The rate of attachment was found to depend highly on colloid size, solution IS and the fraction of the sand surface area favorable for attachment (Sf). The rate of attachment and Sf values were different in batch and column experiments due to differences in the hydrodynamic of the system, and the role of surface roughness and pore structure on colloid attachment. Results from column and batch experiments were generally not comparable, especially for larger colloids (≥0.5μm). Predictions based on classical DLVO theory were found to inadequately describe interaction energies between colloids and sand surfaces.

  6. Adsorption of dyestuff from aqueous solutions through oxalic acid-modified swede rape straw: adsorption process and disposal methodology of depleted bioadsorbents.

    PubMed

    Feng, Yanfang; Dionysiou, Dionysios D; Wu, Yonghong; Zhou, Hui; Xue, Lihong; He, Shiying; Yang, Linzhang

    2013-06-01

    Swede rape straw (Brassica napus L.) was modified by oxalic acid under mild conditions producing an efficient dye adsorbent (SRSOA). This low-cost and environmental friendly bioadsorbent was characterized by various techniques and then applied to purify dye-contaminated aqueous solutions. Equilibrium study showed that the Langmuir model demonstrated the best fit to the equilibrium data and the methylene blue (MB) adsorption capacity calculated by this model was 432mgg(-1). The adsorption process and mechanism is also discussed. To properly deal with the dye-loaded bioadsorbents, the disposal methodology is discussed and a biochar based on depleted bioadsorbents was for the first time produced and examined. This method both solved the disposal problem of contaminant-loaded bioadsorbents and produced an useful adsorbent thereafter. The study indicates that SRSOA is a promising substitute for ACs in purifying dye-contaminated wastewater and that producing biochars from contaminant-loaded bioadsorbents maybe a feasible disposal method.

  7. Molecular Form Differences Between Prostate-Specific Antigen (PSA) Standards Create Quantitative Discordances in PSA ELISA Measurements

    NASA Astrophysics Data System (ADS)

    McJimpsey, Erica L.

    2016-02-01

    The prostate-specific antigen (PSA) assays currently employed for the detection of prostate cancer (PCa) lack the specificity needed to differentiate PCa from benign prostatic hyperplasia and have high false positive rates. The PSA calibrants used to create calibration curves in these assays are typically purified from seminal plasma and contain many molecular forms (intact PSA and cleaved subforms). The purpose of this study was to determine if the composition of the PSA molecular forms found in these PSA standards contribute to the lack of PSA test reliability. To this end, seminal plasma purified PSA standards from different commercial sources were investigated by western blot (WB) and in multiple research grade PSA ELISAs. The WB results revealed that all of the PSA standards contained different mass concentrations of intact and cleaved molecular forms. Increased mass concentrations of intact PSA yielded higher immunoassay absorbance values, even between lots from the same manufacturer. Standardization of seminal plasma derived PSA calibrant molecular form mass concentrations and purification methods will assist in closing the gaps in PCa testing measurements that require the use of PSA values, such as the % free PSA and Prostate Health Index by increasing the accuracy of the calibration curves.

  8. [Coagulation and adsorption on treating the Yellow River and the impact on chlorine decay during chlorination process].

    PubMed

    Zhan, Xiao; Gao, Bao-yu; Liu, Bin; Xu, Chun-hua; Yue, Qin-yan

    2010-05-01

    Two types of inorganic polymer coagulants, polyferric chloride (PFC) and polyaluminum chloride (PAC), were chosen to treat the Yellow River water. Different dosages were investigated in order to investigate the turbidity, UV24, DOC and permanganate index removal efficiency and their coagulation mechanisms based on the Zeta potentials. The natural organic matter removal by the combination of coagulation and adsorption with powder activated carbon were analyzed based on different coagulant and adsorbent dosages and dosing orders. The effects of combination of coagulation and adsorption on the residual chlorine decay were analyzed. The results showed that the two coagulants had high turbidity removal efficiency ( > 90%). The UV254, DOC, permanganate index removal efficiency were 29.2%, 26.1% and 27.9% respectively for PAC coagulation and were 32.3%, 23.3% and 32.9% respectively for PFC. Electric neutralization played an important role in the PAC coagulation process while both adsorption bridging and electric neutralization performed when PFC was used. The removal percentage of organic matter increased with the increase coagulant and adsorbent. The adsorption after coagulation process gave the better UV254 and DOC removal efficiency than the coagulation after adsorption. The UV254 and DOC removal efficiency were 95.2% and 99.9% for PAC coagulation after adsorption and were 90.1% and 99.9% for PFC coagulation first. But adding powder activated carbon can improve floc settlement performance and maintained persistent disinfection effect.

  9. Reformer-pressure swing adsorption process for the production of carbon monoxide

    SciTech Connect

    Fuderer, A.

    1988-02-23

    An improved process for the production of carbon monoxide by the steam reforming of hydrocarbons is described comprising: (a) catalytically reacting a fluid hydrocarbon feed stream with steam in a steam reformer; (b) passing the reformer effluent containing hydrogen, carbon monoxide and carbon dioxide from the steam reformer, without scrubbing to remove the carbon dioxide content thereof, to a pressure swing adsorption system having at least four adsorbent beds, each bed of which, on a cyclic basis, undergoes a processing sequence; (c) recycling the carbon dioxide-rich stream to the steam reformer for reaction with additional quantities of the hydrocarbon feed stream being passed to the stream reformer to form additional quantities of carbon monoxide and hydrogen, with product recovery being enhanced and the need for employing a carbon dioxide wash system being obviated.

  10. Interactive, Online, Adsorption Lab to Support Discovery of the Scientific Process

    NASA Astrophysics Data System (ADS)

    Carroll, K. C.; Ulery, A. L.; Chamberlin, B.; Dettmer, A.

    2014-12-01

    Science students require more than methods practice in lab activities; they must gain an understanding of the application of the scientific process through lab work. Large classes, time constraints, and funding may limit student access to science labs, denying students access to the types of experiential learning needed to motivate and develop new scientists. Interactive, discovery-based computer simulations and virtual labs provide an alternative, low-risk opportunity for learners to engage in lab processes and activities. Students can conduct experiments, collect data, draw conclusions, and even abort a session. We have developed an online virtual lab, through which students can interactively develop as scientists as they learn about scientific concepts, lab equipment, and proper lab techniques. Our first lab topic is adsorption of chemicals to soil, but the methodology is transferrable to other topics. In addition to learning the specific procedures involved in each lab, the online activities will prompt exploration and practice in key scientific and mathematical concepts, such as unit conversion, significant digits, assessing risks, evaluating bias, and assessing quantity and quality of data. These labs are not designed to replace traditional lab instruction, but to supplement instruction on challenging or particularly time-consuming concepts. To complement classroom instruction, students can engage in a lab experience outside the lab and over a shorter time period than often required with real-world adsorption studies. More importantly, students can reflect, discuss, review, and even fail at their lab experience as part of the process to see why natural processes and scientific approaches work the way they do. Our Media Productions team has completed a series of online digital labs available at virtuallabs.nmsu.edu and scienceofsoil.com, and these virtual labs are being integrated into coursework to evaluate changes in student learning.

  11. Experimental and theoretical investigation of water removal from DMAZ liquid fuel by an adsorption process

    NASA Astrophysics Data System (ADS)

    Ghanbari, Shahram; Vaferi, Behzad

    2015-07-01

    2-dimethylaminoethylazide (DMAZ) is a new liquid fuel that has made significant progress in bio/mono propellant rocket engines in recent years. Purification of DMAZ fuel by reducing its water content using various adsorbents including zeolites, calcium chloride and nano-particles is experimentally and theoretically investigated. The highest water adsorption of 92.6% from the DMAZ solution is obtained by the CaCl2 adsorbent within 10 min. Four different artificial neural networks (ANN) are examined to correlate an extent of removed water from the DMAZ solution to its affecting parameters. The performed regression analysis indicated that water initial concentration (WIC), adsorbent types, solution temperature, contact time and adsorbent dosage are the most important affecting variables for water sorption from the DMAZ solution. The accomplished statistical analysis demonstrated a multi-layer perceptron neural network (MLPNN) with seven hidden neurons and is the most accurate approach for modeling the considered task. The obtained results showed that the proposed MLPNN model could be successfully employed for accurate prediction of an amount of water removal from the DMAZ fuel solution by the adsorption process.

  12. Adsorption of paraquat on the physically activated bleaching earth waste from soybean oil processing plant.

    PubMed

    Tsai, W T; Chen, C H; Yang, J M

    2002-09-01

    A series of regeneration experiments with physical activation were carried out on bleaching earth waste from the soybean refining process in a rotary reactor. The influence of activation parameters on the spent clay by varying the holding time of 1 to approximately 4 hours and temperature of 700 to approximately 900 degrees C was determined. The variations of pore properties as well as the change of chemical characteristics in the resulting solids were also studied. Results showed that the resulting samples were type IV with hysteresis loops corresponding to type H3 from nitrogen adsorption-desorption isotherms, indicating slit-shaped mesoporous characteristics. However, the regenerated clays had smaller surface areas (70 to approximately 117 m2/g) than that (245 m2/g) of fresh bleaching earth. Under the physical activation conditions investigated, the holding time of 1 hour and temperature of 700 degrees C were found to be optimal conditions for producing mesoporous clay with physical activation. The adsorption of paraquat on regenerated sample was also evaluated. The isotherm showed that the regenerated sample still had a high affinity for this herbicide. Thus, the regeneration of this agro-industrial waste is one option for utilizing the clay resource, and it may be used for water treatment applications to remove organic contaminants.

  13. Bench Scale Development and Testing of a Novel Adsorption Process for Post-Combustion CO₂ Capture

    SciTech Connect

    Jain, Ravi

    2015-09-01

    A physical sorption process to produce dry CO₂ at high purity (>98%) and high recovery (>90%) from the flue gas taken before or after the FGD was demonstrated both in the lab and in the field (one ton per day scale). A CO₂ recovery of over 94% and a CO₂ purity of over 99% were obtained in the field tests. The process has a moisture, SOX, and Hg removal stage followed by a CO₂ adsorption stage. Evaluations based on field testing, process simulation and detailed engineering studies indicate that the process has the potential for more than 40% reduction in the capital and more than 40% reduction in parasitic power for CO₂ capture compared to MEA. The process has the potential to provide CO₂ at a cost (<$40/tonne) and quality (<1 ppm H₂O, <1 ppm SOX, <10 ppm O₂) suitable for EOR applications which can make CO₂ capture profitable even in the absence of climate legislation. The process is applicable to power plants without SOX, Hg and NOX removal equipment.

  14. Predictive dynamic model of a small pressure swing adsorption air separation unit

    SciTech Connect

    Teague, K.G. Jr.; Edgar, T.F.

    1999-10-01

    A predictive dynamic model of a small pressure swing adsorption (PSA) air separation process was developed for the purposes of evaluation, optimization, and control of oxygen generation systems on board military aircraft. A mathematical model of the adsorption beds was formulated by application of fundamental mass- and energy-transport modeling techniques. These equations were discretized using the Galerkin finite element technique. The resulting ODE systems were coupled with ODEs describing the rate of change of pressure in each bed and models of the feed and exhaust valves and purge orifice. The model was developed so that it is possible to predict the dynamic response of product oxygen composition and feed air consumption to step changes in feed pressure, product flow rate, and cycle time. A laboratory PSA unit similar in size to an on-board oxygen generation system (OBOGS) was constructed to validate the model. The laboratory unit was constructed so that step changes could be implemented and the responses observed for comparison with the model. All parameters in the model were estimated from literature sources with the exception of the feed/exhaust valve and purge orifice discharge coefficients. Excellent dynamic predictions of bed pressure, cycle-averaged feed flow rate, and cycle-averaged bed temperature vs time in response to step changes in all three input variables compared to the two-bed PSA data were achieved without additional parameter estimation from two-bed data.

  15. Effect of two-step functionalization of Ti by chemical processes on protein adsorption

    NASA Astrophysics Data System (ADS)

    Pisarek, M.; Roguska, A.; Andrzejczuk, M.; Marcon, L.; Szunerits, S.; Lewandowska, M.; Janik-Czachor, M.

    2011-07-01

    Titanium and its alloys are widely used for orthopedic and dental implants because of their superior mechanical properties, low modulus, excellent corrosion resistance and good biocompatibility. However, it takes several months for titanium implants and bone tissue to reach integration. Hence, there is growing interest in shortening the process of osseointegration and thereby reducing surgical restrictions. Various surface modifications have been applied to form a bioactive titanium oxide layer on the metal surface, which is known to accelerate osseointegration. The present work shows that titanium dioxide (TiO 2) layers formed on titanium substrates by etching in a solution of sodium hydroxide (NaOH) or hydrogen peroxide/phosphoric acid (H 3PO 4/H 2O 2, with a volume ratio of 1:1) are highly suitable pre-treatments for apatite-like coating deposition. Using a two-step procedure (etching in an alkaline or acidic solution followed by soaking in Hanks' medium), biomimetic calcium phosphate coatings were deposited on porous TiO 2 layers. The combined effects of surface topography and chemistry on the formation of the calcium phosphate layer are presented. The topography of the TiO 2 layers was characterized using HR-SEM and AFM techniques. The nucleation and growth of calcium phosphate (Ca-P) coatings deposited on TiO 2 porous layers from Hanks' solution was investigated using HR-SEM microscopy. AES, XPS and FTIR surface analytical techniques were used to characterize the titanium dioxide layers before and after deposition of the calcium phosphate coatings, as well as after the process of protein adsorption. To evaluate the potential use of such materials for biomedical applications, the adsorption of serum albumin, the most abundant protein in the blood, was studied on such surfaces.

  16. Distribution of ESA's planetary mission data via the Planetary Science Archive (PSA)

    NASA Astrophysics Data System (ADS)

    Heather, David; Barthelemy, Maud; Arviset, Christophe; Osuna, Pedro; Ortiz, Inaki

    interaction with the end-user to input and control the relevant search parameters. - The Map-based Interface is currently operational only for Mars Express HRCS and OMEGA data. This interface allows an end-user to specify a region-of-interest by dragging a box onto a base map of Mars. From this interface, it is possible to directly visualize query results. The Map-based and Classical interfaces are linked and cross-compatible. If a user defines a region-ofinterest in the Map-based interface, the results can be refined by entering more detailed search parameters in the Classical interface. - The Dataset Browser Interface is designed for more experienced users, and allows for direct browsing and access of the data set content through ftp-tree search. Each dataset contains documentation and calibration information in addition to the scientific or engineering data. All data are prepared by the corresponding instrument teams, mostly located in Europe. PSA staff supports the instrument teams in the full archiving process, starting from the definition of the data products, definition of data labels towards the validation and ingestion of the products into the archive. To ensure a common archiving approach for all of ESA's planetary missions as well as to provide a similar data quality and standard for end users, a dataset validation tool was developed supporting the instrument teams in syntactically validating their datasets before delivering to the PSA. In future, a further validation step is envisaged at the PSA to ensure correctness, completeness and cross correlation of all information, label and data content, within a data set. A PSA advisory body has been established in order to assess the continuing development of the PSA. The advisory panel aims to meet regularly, reviewing the progress on defined requirements and providing feedback on our activities.

  17. Acetaldehyde removal using an atmospheric non-thermal plasma combined with a packed bed: role of the adsorption process.

    PubMed

    Klett, C; Duten, X; Tieng, S; Touchard, S; Jestin, P; Hassouni, K; Vega-González, A

    2014-08-30

    This work is an attempt in order to help towards understanding the influence of the adsorption process on the removal of a VOC (acetaldehyde, CH3CHO) using cyclic non thermal plasma (NTP) combined with a packed-bed of a catalyst support, α-Al2O3. In the first part, the results obtained by placing the saturated alumina pellets inside the plasma discharge zone are discussed, in terms of acetaldehyde removal, CO and CO2 production. In the second part, adsorption of CH3CHO, CO, CO2 and O3 was carried out, from single and multicomponent mixtures of the different compounds. The results showed that (i) the adsorption capacities followed the order CH3CHO≫  CO2>CO; (ii) O3 was decomposed on the alumina surface; (iii) CO oxidation occurred on the surface when O3 was present. In the third part, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to follow the alumina surface during acetaldehyde adsorption. DRIFTS measurements demonstrated that besides the bands of molecularly adsorbed acetaldehyde, several absorptions appeared on the spectra showing the intermediate surface transformation of acetaldehyde already at 300K. Finally, the relationship between the adsorption results and the NTP combined with a packed-bed process is discussed.

  18. A protein related to prokaryotic UMP kinases is involved in psaA/B transcript accumulation in Arabidopsis.

    PubMed

    Hein, Paul; Stöckel, Jana; Bennewitz, Stefan; Oelmüller, Ralf

    2009-03-01

    Dpt1 (defect in p saA/B transcript accumulation 1) is a novel photosystem (PS) I mutant in Arabidopsis. dpt1 mutants fail to grow photoautotrophically, and are impaired in the accumulation of psaA/B transcripts while the transcript levels for the remaining PSI subunits, for subunits of the PSII, the cyt-b ( 6 )/f-complex, and the ribulose-1,5-bisphosphate carboxylase are comparable to the wild type. In-organello run-on transcription assays demonstrate that the lower psaA/B transcript abundance in dpt1-1 is not caused by the inability to transcribe the psaA/psaB/rps14 operon. psaA/B transcripts in the mutant are associated with polyribosomes and translated. Thus, the mutation affects post-transcriptional processes specific for psaA/B. The dpt1 gene was isolated by map-based cloning. The protein is localized in the stroma of the chloroplast and exhibits striking similarities to UMP kinases of prokaryotic origin. Our results show that the nuclear encoded protein Dpt1 is essential for retaining photosynthetic activity in higher plant chloroplasts and involved in post-transcriptional steps of psaA/B transcript accumulation. We discuss that Dpt1 may be a bifunctional protein that couples the pyrimidine metabolism to the photosynthetic electron transport.

  19. Intensification of adsorption process by using the pyrolytic char from waste tires to remove chromium (VI) from wastewater.

    PubMed

    Zhou, Jie; Yang, Yong-Rong

    2004-01-01

    Pyrolysis has the potential of transforming waste into valuable recyclable products. Pyrolytic char (PC) is one of the most important products from the pyrolysis of used tires. One of the most significant applications for pyrolytic char recovered is used for the removal of Cr(VI) in the wastewater effluent to control waste by waste. The surface chemistry properties of surface element distribution/concentration and chemical structure were examined for the pyrolytic char and the commercial activated carbon (CAC) respectively. The results showed that surfaces of PC possesses a large amount of ester and hydrocarbon graft, whereas there are mainly carbon functional components of C-OH, C=O and COOH on the surface of CAC. Therefore the surface electronegativity of PC is lower than that of CAC in the water. The repulsive interactions between the surfaces of PC and the negatively charged Cr(VI) ion are weaker than that of CAC, which results in an intensification of the adsorption process by the utilization of PC. The adsorption isotherms of Cr(VI) ion on the two kinds of carbons were determined experimentally. The larger adsorption amount on the PC in the case of Cr(VI) may be attributed mainly to its special surface micro-chemical environment. The mechanism of the removal Cr(VI) from aqueous solution was assumed to be the integration of adsorption and redox reaction. The adsorption was the rate-controlled step for Cr(VI) removal. The adsorption of Cr(VI) was identified as pseudo-second-order kinetics. The rate constants of adsorption were evaluated.

  20. Application of an adsorptive-thermocatalytic process for BTX removal from polluted air flow

    PubMed Central

    2014-01-01

    Background Zero valent iron and copper oxide nanoparticles (30-60 nm) were coated on a bed of natural zeolite (Clinoptilolite) with 1-2 mm grains and arranged as a dual filter in a stainless steel cylindrical reactor (I.D 4.5 cm and L = 30 cm) to investigating the coated bed removal efficiency for BTX. The experiments were conducted in three steps. First, with an air flow of 1.5 L/min and temperature range of 38 (ambient temperature) to 600°C the BTX removal and mineralization was surveyed. Then, in an optimized temperature the effect of flow rate and pollution loading rate were surveyed on BTX removal. Results The BTX removal at 300 and 400°C were respectively up to 87.47% and 94.03%. Also in these temperatures respectively 37.21% and 90.42% of BTX mineralization were achieved. In the retention times of 14.1 s and 7.05 s, respectively 96.18% and 78.42% of BTX was removed. Conclusions According to the results, this adsorptive-thermocatalytic process with using Clinoptilolite as an adsorbent bed and combined Fe0 and Cu2O nanoparticles as catalysts can be an efficient and competitive process in the condition of high flow rate and high pollution loading rate with an adequate process temperature of 350°C. PMID:24955244

  1. Reviewing PSA-based analyses to modify technical specifications at nuclear power plants

    SciTech Connect

    Samanta, P.K.; Martinez-Guridi, G.; Vesely, W.E.

    1995-12-01

    Changes to Technical Specifications (TSs) at nuclear power plants (NPPs) require review and approval by the United States Nuclear Regulatory Commission (USNRC). Currently, many requests for changes to TSs use analyses that are based on a plant`s probabilistic safety assessment (PSA). This report presents an approach to reviewing such PSA-based submittals for changes to TSs. We discuss the basic objectives of reviewing a PSA-based submittal to modify NPP TSs; the methodology of reviewing a TS submittal, and the differing roles of a PSA review, a PSA Computer Code review, and a review of a TS submittal. To illustrate this approach, we discuss our review of changes to allowed outage time (AOT) and surveillance test interval (STI) in the TS for the South Texas Project Nuclear Generating Station. Based on this experience gained, a check-list of items is given for future reviewers; it can be used to verify that the submittal contains sufficient information, and also that the review has addressed the relevant issues. Finally, recommended steps in the review process and the expected findings of each step are discussed.

  2. Optimization of adsorption processes for climate control and thermal energy storage

    SciTech Connect

    Narayanan, S; Yang, S; Kim, H; Wang, EN

    2014-10-01

    Adsorption based heat-pumps have received significant interest owing to their promise of higher efficiencies and energy savings when coupled with waste heat and solar energy compared to conventional heating and cooling systems. While adsorption systems have been widely studied through computational analysis and experiments, general design guidelines to enhance their overall performance have not been proposed. In this work, we identified conditions suitable for the maximum utilization of the adsorbent to enhance the performance of both intermittent as well as continuously operating adsorption systems. A detailed computational model was developed based on a general framework governing adsorption dynamics in a single adsorption layer and pellet. We then validated the computational analysis using experiments with a model system of zeolite 13X-water for different operating conditions. A dimensional analysis was subsequently carried out to optimize adsorption performance for any desired operating condition, which is determined by the choice of adsorbent-vapor pair, adsorption duration, operational pressure, intercrystalline porosity, adsorbent crystal size, and intracrystalline vapor diffusivity. The scaling analysis identifies the critical dimensionless parameters and provides a simple guideline to determine the most suitable geometry for the adsorbent particles. Based on this selection criterion, the computational model was used to demonstrate maximum utilization of the adsorbent for any given operational condition. By considering a wide range of parametric variations for performance optimization, these results offer important insights for designing adsorption beds for heating and cooling systems. (C) 2014 Elsevier Ltd. All rights reserved.

  3. ADSORPTION, DESORPTION AND OXIDATION OF ARSENIC AFFECTED BY CLAY MINERALS AND AGING PROCESS

    EPA Science Inventory

    Adsorption/desorption and oxidation/reduction of arsenic at clay surfaces are very important to the natural attenuation of arsenic in the subsurface environment. Although numerous studies have concluded that iron oxides have high affinities for the adsorption of As(V), very litt...

  4. Response surface optimization of a dynamic dye adsorption process: a case study of crystal violet adsorption onto NaOH-modified rice husk.

    PubMed

    Chowdhury, Shamik; Chakraborty, Sagnik; Saha, Papita Das

    2013-03-01

    The adsorption of crystal violet from aqueous solution by NaOH-modified rice husk was investigated in a laboratory-scale fixed-bed column. A two-level three factor (2(3)) full factorial central composite design with the help of Design Expert Version 7.1.6 (Stat Ease, USA) was used for optimisation of the dynamic dye adsorption process and evaluation of interaction effects of different operating parameters: initial dye concentration (100-200 mg L(-1)), flow rate (10-30 mL min(-1)) and bed height (5-25 cm). A correlation coefficient (R (2)) value of 0.999, model F value of 1,936.59 and its low p value (<0.0001) along with lower value of coefficient of variation (1.38 %) indicated the fitness of the response surface quadratic model developed during the present study. Numerical optimisation applying desirability function was used to identify the optimum conditions for a targeted breakthrough time of 12 h. The optimum conditions were found to be initial solution pH=8.00, initial dye concentration=100 mg L(-1), flow rate=22.88 mL min(-1) and bed height=18.75 cm. A confirmatory experiment was performed to evaluate the accuracy of the optimised procedure. Under the optimised conditions, breakthrough appeared after 12.2 h and the column efficiency was determined as 99 %. The Thomas model showed excellent fit to the dynamic dye adsorption data obtained from the confirmatory experiment. Thereby, it was concluded that the current investigation gives valuable insights for designing and establishing a continuous wastewater treatment plant.

  5. Dye-adsorption capacity of high surface-area hydrogen titanate nanosheets processed via modified hydrothermal method.

    PubMed

    Padinhattayil, Hareesh; Augustine, Rimesh; Shukla, Satyajit

    2013-04-01

    High surface-area (380 m2 x g(-1)) hydrogen titanate nanosheets (HTNS) processed via the modified hydrothermal method have been utilized for the removal of methylene blue (MB) dye from an aqueous solution via the surface-adsorption process involving the electrostatic attraction mechanism. The HTNS have been characterized using the transmission electron microscope (TEM), selected-area electron diffraction (SAED), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) specific surface-area measurement techniques. The amount of MB dye adsorbed on the surface of HTNS at equilibrium (q(e)) has been examined as a function of contact time, initial dye-concentration, and initial solution-pH. Within the investigated range of initial solution-pH (2.5-11), the MB dye adsorption on the surface of HTNS has been observed to follow the pseudo-second-order kinetics with the dye-adsorption capacity of 119 mg x g(-1) at the initial solution-pH of - 10. The adsorption equilibrium follows the Langmuir isotherm within the initial solution-pH range of 2.5-10. However, in a highly basic solution (initial solution-pH -11), the adsorption equilibrium has been observed to follow the Langmuir, Freundlich, and Dubinin-Kaganer-Radushkevich (DKR) models in the different ranges of initial MB dye concentration. The mere dependence on the DKR model has not been observed within the investigated range of initial solution-pH. The differences in the dye-adsorption characteristics and capacity of HTNS, compared with those of hydrogen titanate nanotubes, have been attributed to the difference in their specific surface-area. Irrespective of the morphology, the maximum coverage of MB dye on the surface of hydrogen titanate has been noted to be the same (52%).

  6. Effect of process variables interaction on simultaneous adsorption of phenol and 4-chlorophenol: statistical modeling and optimization using RSM

    NASA Astrophysics Data System (ADS)

    Leong, Kwok-Yii; See, Sylvia; Lim, Jun-Wei; Bashir, Mohammed J. K.; Ng, Choon-Aun; Tham, Leony

    2016-02-01

    Results of the interaction of process variables and the consequential mixture of phenolic compounds adsorption study are expected to shed brighter light on the wastewater treatment applications. Accordingly, the aims of this research are to model and optimize the process variables which impinged on the simultaneous adsorption of phenol and 4-chlorophenol (4-CP) in the binary solution by spherical activated carbon (SAC). Batch assessments were designed using response surface methodology software. The process variables, namely SAC dosage and pH were varied over the 1.50-3.50 g/L and 4.00-9.00 g/L ranges, respectively, were experimented. The analysis of variance results showed the significant models could precisely predict the percentage removals of phenol and 4-CP, indicating models reliability. The interaction of process variables was inconspicuous for the case of phenol adsorption. However, increasing the pH would deteriorate the 4-CP adsorption which was partially offset by raising the SAC dosage. Considering the environmental benefits, optimization taken place at the SAC dosage and pH of 3.50 g/L and 7.60 g/L, respectively, was selected. By employing the optimized conditions of SAC dosage of 3.50 g/L at pH 7.60 for the adsorption process, the predicted phenol and 4-CP removal percentages were found to be 85.4 % (73.1 mg/g) and 96.2 % (82.6 mg/g), respectively, which were in agreement with the experimental runs.

  7. [Evaluation of (-2)proPSA in combination with total PSA and free PSA for the early detection of prostate cancer].

    PubMed

    Lamy, Pierre-Jean; Montels, Frédéric; Tosi, Diego; Leizour, Benoit; Bascoul-Mollevi, Caroline; Castan, Florence; Roques, Sylvie; Nielloud, Fabien; Rebillard, Xavier

    2013-01-01

    The analytical and clinical validation of new biomarkers for the early detection of prostate is necessary. (-2)proPSA, total PSA and free PSA values are used to calculate a standardized PHI index linked to a higher probability of a positive biopsy in patients with PSA levels between 3-4 and 10 ng/L, the gray zone for prostate cancer diagnosis. The purpose of this study is to validate the analytical performance of the (-2)proPSA and to determine the predictive value of PHI for the early detection of prostate cancer. Analytical performances are correct. It is not necessary to dilute samples before analysis. The stability of (-2)proPSA is good until at least 3 hours at room temperature before centrifugation. The study of the PSAT, PSAL, (-2)proPSA and PHI values in a population of patients consulting for an early prostate cancer diagnosis shows that the index PHI is the most powerful predictive marker of cancer with an area under ROC curve of 0.70, whereas it is only 0.56 for total PSA.

  8. Feasibility of bioengineered two-stages sequential batch reactor and filtration-adsorption process for complex agrochemical effluent.

    PubMed

    Manekar, Pravin; Biswas, Rima; Urewar, Chaitali; Pal, Sukdeb; Nandy, Tapas

    2013-11-01

    In the present study, the feasibility of a bioengineered two-stages sequential batch reactor (BTSSBR) followed by filtration-adsorption process was investigated to treat the agrochemical effluent by overcoming factor affecting process stability such as microbial imbalance and substrate sensitivity. An air stripper stripped 90% of toxic ammonia, and combined with other streams for bio-oxidation and filtration-adsorption. The BTSSBR system achieved bio-oxidation at 6 days hydraulic retention time by fending off microbial imbalance and substrate sensitivity. The maximum reduction in COD and BOD by heterotrophic bacteria in the first reactor was 87% and 90%, respectively. Removal of toxic ammoniacal-nitrogen by autotrophic bacteria in a post-second stage bio-oxidation was 97%. The optimum filtration and adsorption of pollutants were achieved at a filtration rate of 10 and 9 m(3)m(-2)h(-1), respectively. The treatment scheme comprising air stripper, BTSSBR and filtration-adsorption process showed a great promise for treating the agrochemical effluent.

  9. Interoperability In The New Planetary Science Archive (PSA)

    NASA Astrophysics Data System (ADS)

    Rios, C.; Barbarisi, I.; Docasal, R.; Macfarlane, A. J.; Gonzalez, J.; Arviset, C.; Grotheer, E.; Besse, S.; Martinez, S.; Heather, D.; De Marchi, G.; Lim, T.; Fraga, D.; Barthelemy, M.

    2015-12-01

    As the world becomes increasingly interconnected, there is a greater need to provide interoperability with software and applications that are commonly being used globally. For this purpose, the development of the new Planetary Science Archive (PSA), by the European Space Astronomy Centre (ESAC) Science Data Centre (ESDC), is focused on building a modern science archive that takes into account internationally recognised standards in order to provide access to the archive through tools from third parties, for example by the NASA Planetary Data System (PDS), the VESPA project from the Virtual Observatory of Paris as well as other international institutions. The protocols and standards currently being supported by the new Planetary Science Archive at this time are the Planetary Data Access Protocol (PDAP), the EuroPlanet-Table Access Protocol (EPN-TAP) and Open Geospatial Consortium (OGC) standards. The architecture of the PSA consists of a Geoserver (an open-source map server), the goal of which is to support use cases such as the distribution of search results, sharing and processing data through a OGC Web Feature Service (WFS) and a Web Map Service (WMS). This server also allows the retrieval of requested information in several standard output formats like Keyhole Markup Language (KML), Geography Markup Language (GML), shapefile, JavaScript Object Notation (JSON) and Comma Separated Values (CSV), among others. The provision of these various output formats enables end-users to be able to transfer retrieved data into popular applications such as Google Mars and NASA World Wind.

  10. A combined process of adsorption and Fenton-like oxidation for furfural removal using zero-valent iron residue.

    PubMed

    Li, Furong; Bao, Jianguo; Zhang, Tian C; Lei, Yutian

    2015-01-01

    In this study, the feasibility of using a combined adsorption and Fenton-like oxidation process (with zero-valent iron (ZVI) residue from heat wraps as an absorbent and catalyst) to remove furfural in the solution was evaluated. The influencing parameters (e.g. pH, H2O2 concentration, initial furfural concentration) and the reusability of ZVI residue (to replace the iron powder) were estimated. The ZVI residue was found to have much better adsorption effect on furfural at pH 2.0 compared with pH 6.7. For Fenton-like reaction alone with ZVI residue, the highest furfural removal of 97.5% was observed at the concentration of 0.176 mol/L H2O2, and all of the samples had >80% removal efficiency at different initial furfural concentrations of 2, 10, 20, 30 and 40 mmol/L. However, with a combined adsorption and Fenton-like oxidation, the removal efficiency of furfural was nearly 100% for all treatments. The ZVI residue used for furfural removal was much better than that of iron powder in the Fenton-like reaction at a seven-cycle experiment. This study suggests the combined process of adsorption and Fenton-like oxidation using ZVI residue is effective for the treatment of furfural in the liquid.

  11. Granular activated carbon for simultaneous adsorption and biodegradation of toxic oil sands process-affected water organic compounds.

    PubMed

    Islam, Md Shahinoor; Zhang, Yanyan; McPhedran, Kerry N; Liu, Yang; Gamal El-Din, Mohamed

    2015-04-01

    Naphthenic acids (NAs) released into oil sands process-affected water (OSPW) during bitumen processing in Northern Alberta are problematic for oil sands industries due to their toxicity in the environment and resistance to degradation during conventional wastewater treatment processes. Granular activated carbon (GAC) has shown to be an effective media in removing biopersistent organics from wastewater using a combination of adsorption and biodegradation removal mechanisms. A simultaneous GAC (0.4 g GAC/L) adsorption and biodegradation (combined treatment) study was used for the treatment of raw and ozonated OSPW. After 28 days of batch treatment, classical and oxidized NAs removals for raw OSPW were 93.3% and 73.7%, and for ozonated OSPW were 96.2% and 77.1%, respectively. Synergetic effects of the combined treatment process were observed in removals of COD, the acid extractable fraction, and oxidized NAs, which indicated enhanced biodegradation and bioregeneration in GAC biofilms. A bacteria copy number >10(8) copies/g GAC on GAC surfaces was found using quantitative real time polymerase chain reaction after treatment for both raw and ozonated OSPW. A Microtox(®) acute toxicity test (Vibrio fischeri) showed effective toxicity removal (>95.3%) for the combined treatments. Therefore, the simultaneous GAC adsorption and biodegradation treatment process is a promising technology for the elimination of toxic OSPW NAs.

  12. PSA and beyond: alternative prostate cancer biomarkers

    PubMed Central

    2016-01-01

    Background The use of biomarkers for prostate cancer screening, diagnosis and prognosis has the potential to improve the clinical management of the patients. Owing to inherent limitations of the biomarker prostate-specific antigen (PSA), intensive efforts are currently directed towards a search for alternative prostate cancer biomarkers, particularly those that can predict disease aggressiveness and drive better treatment decisions. Methods A literature search of Medline articles focused on recent and emerging advances in prostate cancer biomarkers was performed. The most promising biomarkers that have the potential to meet the unmet clinical needs in prostate cancer patient management and/or that are clinically implemented were selected. Conclusions With the advent of advanced genomic and proteomic technologies, we have in recent years seen an enormous spurt in prostate cancer biomarker research with several promising alternative biomarkers being discovered that show an improved sensitivity and specificity over PSA. The new generation of biomarkers can be tested via serum, urine, or tissue-based assays that have either received regulatory approval by the US Food and Drug Administration or are available as Clinical Laboratory Improvement Amendments-based laboratory developed tests. Additional emerging novel biomarkers for prostate cancer, including circulating tumor cells, microRNAs and exosomes, are still in their infancy. Together, these biomarkers provide actionable guidance for prostate cancer risk assessment, and are expected to lead to an era of personalized medicine. PMID:26790878

  13. A method for screening the potential of MOFs as CO2 adsorbents in pressure swing adsorption processes.

    PubMed

    Pirngruber, Gerhard D; Hamon, Lomig; Bourrelly, Sandrine; Llewellyn, Philip L; Lenoir, Estelle; Guillerm, Vincent; Serre, Christian; Devic, Thomas

    2012-04-01

    This work reports the adsorption and coadsorption data of CO(2)/CH(4)/CO mixtures on several metal-organic frameworks [MOFs; MIL-100(Cr), MIL-47(V), MIL-140(Zr)-A, Cu-btc, and MIL-53(Cr)] and compares them with reference adsorbents, that is, zeolite NaX and an activated carbon material, AC35. We also evaluate the effect of H(2)O on CO(2) adsorption and on the stability of the structures. Based on the experimental adsorption data, the performance potential of MOFs in several pressure swing adsorption processes is estimated by making a ranking of working capacities and separation factors. We discuss the separation of biogas, the purification of H(2) produced by steam reforming of methane, and the removal of CO(2) from synthesis gas in IGCC (integrated gasification combined cycle) systems. Some MOFs are very well placed in the ranking of (isothermal) working capacity vs. selectivity. Yet, performance is not the only criterion for the selection of MOFs. Ease and cost of synthesis and long-term stability are other important aspects that have to be taken into account.

  14. Simultaneous Online Measurement of H2O and CO2 in the Humid CO2 Adsorption/Desorption Process.

    PubMed

    Yu, Qingni; Ye, Sha; Zhu, Jingke; Lei, Lecheng; Yang, Bin

    2015-01-01

    A dew point meter (DP) and an infrared (IR) CO2 analyzer were assembled in a humid CO2 adsorption/desorption system in series for simultaneous online measurements of H2O and CO2, respectively. The humidifier, by using surface-flushing on a saturated brine solution was self-made for the generation of humid air flow. It was found that by this method it became relatively easy to obtain a low H2O content in air flow and that its fluctuation could be reduced compared to the bubbling method. Water calibration for the DP-IR detector is necessary to be conducted for minimizing the measurement error of H2O. It demonstrated that the relative error (RA) for simultaneous online measurements H2O and CO2 in the desorption process is lower than 0.1%. The high RA in the adsorption of H2O is attributed to H2O adsorption on the transfer pipe and amplification of the measurement error. The high accuracy of simultaneous online measurements of H2O and CO2 is promising for investigating their co-adsorption/desorption behaviors, especially for direct CO2 capture from ambient air.

  15. Application of SBA-15 in Adsorption-Fenton Oxidation Process for Simultaneous Remediation of Dehp and As(iii)

    NASA Astrophysics Data System (ADS)

    Latorre, I.; Hwang, S.

    2013-12-01

    Di-2-ethylhexyl phthalate (DEHP) has been widely used as plasticizer in the manufacturing of polymeric materials to enhance flexibility, transparency and softness, particularly, in polyvinyl chloride (PVC) production. Several studies elucidated that DEHP could be linked to hepatocellular tumors and pre-term birth and may be a developmental and reproductive toxicant. Arsenic (As) contamination has been widespread in the environment and because of its toxicity and prevalence in nature; it also has become a significant environmental health concern. Most solid waste materials containing DEHP and As(III) are disposed of in landfills and may migrate to groundwater and soil environments representing a threat to human receptors. Therefore, the application of adsorption-Fenton oxidation process with Fe adsorbed to SBA-15 matrix was assessed for simultaneous remediation of DEHP and As(III). Three sequences were run to assess the regeneration efficiency of the SBA-15. A response surface methodology was employed to optimize adsorption and Fenton regeneration. Adsorption optimization was evaluated with regard to SBA-15 doses and the extent of As(III) and Fe concentrations. Optimization of Fenton regeneration, in addition, assessed initial H2O2 concentration. Global optimization for maximum reduction of DEHP and As(III) was performed by D-Optimal. Highest adsorption of DEHP (90-95%) and As (40-95%) into the SBA-15 was predicted at 1.16 mM Fe, 18.74 mg SBA-15 and 3.71 mg/L As(III). Highest reduction of As (78-99%) and DEHP (90-97%) was predicted with 0.50 mM Fe, 22 mg SBA-15, 3.02 mg/L As(III) and 22.50 mM H2O2. Global optimal treatments were validated and SBA-15 regenerated material was characterized via SEM and XPS. The efficiency of DEHP and As(III) remediation by adsorption-Fenton oxidation process, applying optimal treatment combinations, was evaluated using leachate from a lab scale bioreactor monofill (i.e., filled with PVC materials). Capability of As(III) and DEHP

  16. Statistical optimization of adsorption processes for removal of 2,4-dichlorophenol by activated carbon derived from oil palm empty fruit bunches.

    PubMed

    Alam, M Zahangir; Muyibi, Suleyman A; Toramae, Juria

    2007-01-01

    The adsorption capacity of activated carbon produced from oil palm empty fruit bunches through removal of 2,4-dichlorophenol from aqueous solution was carried out in the laboratory. The activated carbon was produced by thermal activation of activation time with 30 min at 800 degrees C. The adsorption process conditions were determined with the statistical optimization followed by central composite design. A developed polynomial model for operating conditions of adsorption process indicated that the optimum conditions for maximum adsorption of phenolic compound were: agitation rate of 100 r/min, contact time of 8 h, initial adsorbate concentration of 250 mg/L and pH 4. Adsorption isotherms were conducted to evaluate biosorption process. Langmuir isotherm was more favorable (R2 = 0.93) for removal of 2,4-dichlorophenol by the activated carbon rather than Freundlich isotherm (R2 = 0.88).

  17. The elimination of siloxanes from the biogas of a wastewater treatment plant by means of an adsorption process.

    PubMed

    Trapote, Arturo; García, Mariano; Prats, Daniel

    2016-12-01

    Siloxanes present in the biogas produced during anaerobic digestion in wastewater treatment plants (WWTPs) can damage the mechanism of cogeneration heat engines and obstruct the process of energy valorization. The objective of this research is to detect the presence of siloxanes in the biogas and evaluate a procedure for their elimination. A breakthrough curve of a synthetic decamethylcyclopentasiloxane on an experimental bed of activated carbon was modeled and the theoretical mathematical model of the adsorption process was adjusted. As a result, the constants of the model were obtained: the mass transfer constant, Henry's equilibrium constant, and the Eddy diffusion. The procedure developed allows the adsorption equilibrium of siloxanes on activated carbon to be predicted, and makes it possible to lay the basis for the design of an appropriate activated carbon module for the elimination of siloxanes in a WWTP.

  18. Removal of inhibitors from pre-hydrolysis liquor of kraft-based dissolving pulp production process using adsorption and flocculation processes.

    PubMed

    Liu, Xin; Fatehi, Pedram; Ni, Yonghao

    2012-07-01

    A process for removing inhibitors from pre-hydrolysis liquor (PHL) of a kraft-based dissolving pulp production process by adsorption and flocculation, and the characteristics of this process were studied. In this process, industrially produced PHL was treated with unmodified and oxidized activated carbon as an absorbent and polydiallyldimethylammonium chloride (PDADMAC) as a flocculant. The overall removal of lignin and furfural in the developed process was 83.3% and 100%, respectively, while that of hemicelluloses was 32.7%. These results confirmed that the developed process can remove inhibitors from PHL prior to producing value-added products, e.g. ethanol and xylitol via fermentation.

  19. Study of the adsorption and electroadsorption process of Cu (II) ions within thermally and chemically modified activated carbon.

    PubMed

    Macías-García, A; Gómez Corzo, M; Alfaro Domínguez, M; Alexandre Franco, M; Martínez Naharro, J

    2017-04-15

    The aim of this work is to modify the porous texture and superficial groups of a commercial activated carbon through chemical and thermal treatment and subsequently study the kinetics of adsorption and electroadsorption of Cu (II) ion for these carbons. Samples of three activated carbons were used. These were a commercial activated carbon, commercial activated carbon modified thermically (C-N2-900) and finally commercial activated carbon modified chemically C-SO2-H2S-200. The activated carbons were characterized chemically and texturally and the electrical conductivity of them determined. Different kinetic models were applied. The kinetics of the adsorption and electroadsorption process of the Cu (II) ion fits a pseudo second order model and the most likely mechanism takes place in two stages. A first step through transfer of the metal mass through the boundary layer of the adsorbent and distribution of the Cu (II) on the external surface of the activated carbon and a second step that represents intraparticle diffusion and joining of the Cu (II) with the active centres of the activated carbon. Finally, the kinetics of the adsorption process are faster than the kinetics of the electroadsorption but the percentage of the Cu (II) ion retained is much higher in the electroadsorption process.

  20. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Monomer Adsorption-Desorption Processes

    NASA Astrophysics Data System (ADS)

    Ke, Jian-Hong; Lin, Zhen-Quan; Chen, Xiao-Shuang

    2009-05-01

    We propose an adsorption-desorption model for a deposit growth system, in which the adsorption and desorption of particles coexist. By means of the generalized rate equation we investigate the cluster (island) size distribution in the dynamic equilibrium state. The results show that the evolution behaviour of the system depends crucially on the details of the rate kernels. The cluster size distribution can take the scale-free power-law form in some cases, while it grows exponentially with size in other cases.

  1. Direct transfer-adsorption: The new molecular dynamics transition mechanism of nano-diamond preparation by laser shock processing

    NASA Astrophysics Data System (ADS)

    Ren, X. D.; Tang, S. X.; Zheng, L. M.; Yuan, S. Q.; Ren, N. F.; Yang, H. M.; Wang, Y.; Zhou, W. F.; Xu, S. D.

    2015-07-01

    Laser shock processing induced structural transformation in graphite cluster of about 3 nm diameter is simulated through molecular dynamics simulations. The Brenner potential is utilized to characterize short-range order while Lennard-Jones potential for long-range order. The effect of high-energy laser shock on graphite was simulated with corresponding temperature and pressure load applied to the graphite cluster. The graphite cluster was found to transform into nano-diamond, crystal structures and amorphous carbon after heating-pressing and annealing-decompression by analyzing pair distribution function g(r) and atomic snapshots process. An interesting mechanism 'direct transfer-adsorption' for promoting peripheral carbon atoms of the graphite cluster into the inner layer and transforming bonds from sp2-type to sp3-type within the inner carbon atoms is investigated. The 'direct transfer-adsorption' mechanism, which prevails under the conditions of a temperature higher than 4300 K and a pressure higher than 15 GPa, is at fast cooling rates and high densities. And the 'direct transfer-adsorption' mechanism plays a key role in the conversion from graphite to diamond.

  2. Application of high silica zeolite ZSM-5 in a hybrid treatment process based on sequential adsorption and ozonation for VOCs elimination.

    PubMed

    Zaitan, Hicham; Manero, Marie Hélène; Valdés, Héctor

    2016-03-01

    In this study, a hydrophobic synthetic zeolite, namely ZSM-5 is chosen as an adsorbent/catalyst for toluene removal. Experimental results showed that toluene adsorption onto ZSM-5 was favourable, following a Langmuir adsorption isotherm model. ZSM-5 zeolite was regenerated using gaseous ozone at low temperature. Adsorbed toluene was oxidised, releasing mainly CO2 and H2O. Traces of oxidation by-products such as acetic acid and acetaldehyde were formed and remained adsorbed after the oxidativate regeneration with ozone. After four successive cycles of adsorption/ozonation, the adsorption efficiency was not affected (92%-99%). These results showed that volatile organic compound (VOC) removal by adsorption onto ZSM-5 zeolite followed by ozone regeneration could be used as a promising hybrid process for the control of VOC emissions in terms of efficiency.

  3. Novel simple process for tocopherols selective recovery from vegetable oils by adsorption and desorption with an anion-exchange resin.

    PubMed

    Hiromori, Kousuke; Shibasaki-Kitakawa, Naomi; Nakashima, Kazunori; Yonemoto, Toshikuni

    2016-03-01

    A novel and simple low-temperature process was used to recover tocopherols from a deodorizer distillate, which is a by-product of edible oil refining. The process consists of three operations: the esterification of free fatty acids with a cation-exchange resin catalyst, the adsorption of tocopherols onto an anion-exchange resin, and tocopherol desorption from the resin. No degradation of tocopherols occurred during these processes. In the tocopherol-rich fraction, no impurities such as sterols or glycerides were present. These impurities are commonly found in the product of the conventional process. This novel process improves the overall recovery ratio and the mass fraction of the product (75.9% and 51.0wt%) compared with those in the conventional process (50% and 35wt%).

  4. Adsorption removal of pollutants by active cokes produced from sludge in the energy recycle process of wastes.

    PubMed

    Kojima, Naozumi; Mitomo, Aki; Itaya, Yoshinori; Mori, Shigekatsu; Yoshida, Shuichi

    2002-01-01

    This study proposes a recycling system of sludge into active cokes and the fundamental examinations for the application were carried out. In the system, active cokes were produced by carbonizing pellets of sludge in a steam stream. Pyrolysis gas yielded by carbonization can be available to a fuel for a steam generation boiler. The exhaust heat from the boiler is used sequentially for drying of sludge. The active cokes are applied to the adsorbent for dioxin removal in exhaust gas from incinerators of wastes, or for purification of gas obtained in a gasification process of wastes, particularly removal of H2S. The used adsorbent is not recycled, but incinerated in the furnace without a desorption process to decompose adsorbed dioxin or to oxidize H2S for a sequential desulfurization process of SO2. Dry pellets of sludge were carbonized in a quartz tube reactor under various atmospheres. The micro pore structure and the adsorption performance of the cokes produced without activation process were examined. The micro pore structure was influenced by the temperature, the sort of flow gas (N2, CO2 and steam) and carbonization time, and the active cokes produced under the condition of the temperature 823 K for 60 min in the steam atmosphere had a largest specific surface area in the diameter less than 5 nm. The amount of benzene adsorption as an alternative substance of dioxin into the active cokes had a similar quality to a commercial active char produced from coal if it was evaluated by adsorption per a unit specific surface area. This fundamental knowledge must be reflected to an optimum design for development of a simple continuous process to produce the active cokes by a fluidized bed type of the carbonization furnace.

  5. Racial differences in PSA screening interval and stage at diagnosis

    PubMed Central

    Carpenter, William R.; Howard, Daniel L.; Taylor, Yhenneko J.; Ross, Louie E.; Wobker, Sara E.; Godley, Paul A.

    2010-01-01

    Objectives This study examined PSA screening interval of black and white men aged 65 or older and its association with prostate cancer stage at diagnosis. Methods SEER-Medicare data were examined for 18,067 black and white men diagnosed with prostate cancer between 1994 and 2002. Logistic regression was used to assess the association between race, PSA screening interval, and stage at diagnosis. Analysis also controlled for age, marital status, comorbidity, diagnosis year, geographic region, income, and receipt of surgery. Results Compared to whites, blacks diagnosed with prostate cancer were more likely to have had a longer PSA screening interval prior to diagnosis, including a greater likelihood of no pre-diagnosis use of PSA screening. Controlling for PSA screening interval was associated with a reduction in blacks’ relative odds of being diagnosed with advanced (stage III or IV) prostate cancer, to a point that the stage at diagnosis was not statistically different from that of whites (OR=1.12, 95% CI=0.98–1.29). Longer intra-PSA intervals were systematically associated with greater odds of diagnosis with advanced disease. Conclusions More frequent or systematic PSA screening may be a pathway to reducing racial differences in prostate cancer stage at diagnosis, and, by extension, mortality. PMID:20333462

  6. Molecular mechanism of the adsorption process of an iodide anion into liquid-vapor interfaces of water-methanol mixtures

    NASA Astrophysics Data System (ADS)

    Annapureddy, Harsha V. R.; Dang, Liem X.

    2012-12-01

    To enhance our understanding of the molecular mechanism of ion adsorption to the interface of mixtures, we systematically carried out a free energy calculations study involving the transport of an iodide anion across the interface of a water-methanol mixture. Many body affects are taken into account to describe the interactions among the species. The surface propensities of I- at interfaces of pure water and methanol are well understood. In contrast, detailed knowledge of the molecular level adsorption process of I- at aqueous mixture interfaces has not been reported. In this paper, we explore how this phenomenon will be affected for mixed solvents with varying compositions of water and methanol. Our potential of mean force study as function of varying compositions indicated that I- adsorption free energies decrease from pure water to pure methanol but not linearly with the concentration of methanol. We analyze the computed density profiles and hydration numbers as a function of concentrations and ion positions with respect to the interface to further explain the observed phenomenon.

  7. Molecular Mechanism of the Adsorption Process of an Iodide Anion into Liquid-Vapor Interfaces of Water-Methanol Mixtures

    SciTech Connect

    Annapureddy, Harsha V.; Dang, Liem X.

    2012-12-07

    To enhance our understanding of the molecular mechanism of ion adsorption to the interface of mixtures, we systematically carried out a free energy calculations study involving the transport of an iodide anion across the interface of a water-methanol mixture. Many body affects are taken into account to describe the interactions among the species. The surface propensities of I- at interfaces of pure water and methanol are well understood. In contrast, detailed knowledge of the molecular level adsorption process of I- at aqueous mixture interfaces has not been reported. In this paper, we explore how this phenomenon will be affected for mixed solvents with varying compositions of water and methanol. Our potential of mean force study as function of varying compositions indicated that I- adsorption free energies decrease from pure water to pure methanol but not linearly with the concentration of methanol. We analyze the computed density profiles and hydration numbers as a function of concentrations and ion positions with respect to the interface to further explain the observed phenomenon. This work was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences (BES), Division of Chemical Sciences, Geosciences, and Biosciences. Pacific Northwest National Laboratory is a multiprogram national laboratory operated for DOE by Battelle. The calculations were carried out using computer resources provided by BES.

  8. Enhanced nitrogen removal in a wastewater treatment process characterized by carbon source manipulation with biological adsorption and sludge hydrolysis.

    PubMed

    Liu, Hongbo; Zhao, Fang; Mao, Boyang; Wen, Xianghua

    2012-06-01

    An innovative adsorption/nitrification/denitrification/sludge-hydrolysis wastewater treatment process (ENRS) characterized by carbon source manipulation with a biological adsorption unit and a sludge hydrolysis unit was developed to enhance nitrogen removal and reduce sludge production for municipal wastewater treatment. The system presented good performance in pollutants removal, yielding the effluent with average COD, NH(4)(+)-N, TN and TP of 48.5, 0.6, 13.2 and 1.0 mg/L, respectively. Sixty percent of the total carbon source in the influent was concentrated and separated by the quick adsorption of activated sludge, providing the possibilities of reusing waste carbon source in the denitrification tank and accumulating nitrobacteria in the nitrification tank. Low temperature of 6-15 °C and high hydraulic loading rate of 3.0-15.0 m(3)/d did not affect NH(4)(+)-N removal performance, yielding the NH(4)(+)-N of lower 1.0 mg/L in the effluent. Furthermore, 50% of the residual sludge in the ENRS system could be transformed into soluble COD (SCOD) by alkaline thermal hydrolysis with temperature of 60 °C and pH of 11, and the hydrolyzed carbon could completely substitute methanol as a good quality carbon to support high efficient denitrification.

  9. An overview of landfill leachate treatment via activated carbon adsorption process.

    PubMed

    Foo, K Y; Hameed, B H

    2009-11-15

    Water scarcity and pollution rank equal to climate change as the most urgent environmental issue for the 21st century. To date, the percolation landfill leachate into the groundwater tables and aquifer systems which poses a potential risk and potential hazards towards the public health and ecosystems, remains an aesthetic concern and consideration abroad the nations. Arising from the steep enrichment of globalization and metropolitan growth, numerous mitigating approaches and imperative technologies have currently drastically been addressed and confronted. Confirming the assertion, this paper presents a state of art review of leachate treatment technologies, its fundamental background studies, and environmental implications. Moreover, the key advance of activated carbons adsorption, its major challenges together with the future expectation are summarized and discussed. Conclusively, the expanding of activated carbons adsorption represents a potentially viable and powerful tool, leading to the superior improvement of environmental conservation.

  10. Expression System Based on an MTIIa Promoter to Produce hPSA in Mammalian Cell Cultures

    PubMed Central

    Santos, Anderson K.; Parreira, Ricardo C.; Resende, Rodrigo R.

    2016-01-01

    Because of the limitations of standard culture techniques, the development of new recombinant protein expression systems with biotechnological potential is a key challenge. Ideally, such systems should be able to effectively and accurately synthesize a protein of interest with intrinsic metabolic capacity. Here, we describe such a system that was designed based on a plasmid vector containing promoter elements derived from the metallothionein MTIIa promoter, as well as processing and purification elements. This promoter can be induced by heavy metals in a culture medium to induce the synthesis of human prostate-specific antigen (hPSA), which has been modified to insert elements for purification, proteolysis, and secretion. We optimized hPSA production in this system by comparing the effects and contributions of ZnCl2, CdCl2, and CuSO4 in HEK293FT, HeLa, BHK-21, and CHO-K1 cells. We also compared the effectiveness of three different transfection agents: multi-walled carbon nanotubes, Lipofectamine 2000, and X-tremeGENE HP Reagent. hPSA production was confirmed via the detection of enhanced green fluorescent protein fluorescence, and cell viability was determined. The expression of hPSA was compared with that of the native protein produced by LNCaP cells, using enzyme-linked immunosorbent assay and sodium dodecyl sulfate polyacrylamide gel electrophoresis. X-tremeGENE reagent, the BHK-21 cell line, and CuSO4 showed the highest hPSA production rates. Furthermore, BHK-21 cells were more resistant to the oxidative stress caused by 100 μM CuSO4. These results suggest that the proposed optimized inducible expression system can effectively produce recombinant proteins with desired characteristics for a wide range of applications in molecular biology. PMID:27582737

  11. Optimisation of slow-pyrolysis process conditions to maximise char yield and heavy metal adsorption of biochar produced from different feedstocks.

    PubMed

    Hodgson, E; Lewys-James, A; Rao Ravella, S; Thomas-Jones, S; Perkins, W; Gallagher, J

    2016-08-01

    The objective of this work was to identify biomass feedstocks and optimum pyrolysis process conditions to produce a biochar capable of adsorbing metals from polluted groundwater. Taguchi experimental design was used to determine the effects of slow-pyrolysis process conditions on char yield and zinc adsorption. Treatments were repeated using six candidate feedstocks (Lolium perenne, Lolium perenne fibre, Miscanthus x giganteus, Salix viminalis, Fraxinus excelsior and Picea sitchensis) and the resultant chars were tested for metal adsorption performance. Chars produced from L. perenne and its extracted fibre displayed the greatest zinc adsorption performance and removed 83.27-92.96% respectively. Optimum process conditions in terms of both char yield and zinc adsorption performance were achieved from slow-pyrolysis at 300°C for 2h using a feedstock with a particle size of less than 1mm.

  12. nanoparticles via a facile one-step solvothermal process for adsorption of bovine serum albumin

    NASA Astrophysics Data System (ADS)

    Shen, Mao; Yu, Yujing; Fan, Guodong; Chen, Guang; Jin, Ying min; Tang, Wenyuan; Jia, Wenping

    2014-06-01

    Preparation of magnetic nanoparticles coated with chitosan (CS-coated Fe3O4 NPs) in one step by the solvothermal method in the presence of different amounts of added chitosan is reported here. The magnetic property of the obtained magnetic composite nanoparticles was confirmed by X-ray diffraction (XRD) and magnetic measurements (VSM). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) allowed the identification of spherical nanoparticles with about 150 nm in average diameter. Characterization of the products by Fourier transform infrared spectroscopy (FTIR) demonstrated that CS-coated Fe3O4 NPs were obtained. Chitosan content in the obtained nanocomposites was estimated by thermogravimetric analysis (TGA). The adsorption properties of the CS-coated Fe3O4 NPs for bovine serum albumin (BSA) were investigated under different concentrations of BSA. Compared with naked Fe3O4 nanoparticles, the CS-coated Fe3O4 NPs showed a higher BSA adsorption capacity (96.5 mg/g) and a fast adsorption rate (45 min) in aqueous solutions. This work demonstrates that the prepared magnetic nanoparticles have promising applications in enzyme and protein immobilization.

  13. Effect of particle adsorption rates on the disproportionation process in pickering stabilised bubbles

    NASA Astrophysics Data System (ADS)

    Ettelaie, Rammile; Murray, Brent

    2014-05-01

    The degree of shrinkage of particle stabilised bubbles of various sizes, in a polydisperse bubble dispersion, has been investigated in the light of the finite adsorption times for the particles and the disproportionation kinetics of the bubbles. For the case where the system contains an abundance of particles we find a threshold radius, above which bubbles are stabilised without any significant reduction in their size. Bubbles with an initial radius below this threshold on the other hand undergo a large degree of shrinkage prior to stabilisation. As the ratio of the available particles to the bubbles is reduced, it is shown that the final bubble size, for the larger bubbles in the distribution, becomes increasingly governed by the number of particles, rather than their adsorption time per se. For systems with "adsorption controlled" shrinkage ratio, the final bubble distribution is found to be wider than the initial one, while for a "particle number controlled" case it is actually narrower. Starting from a unimodal bubble size distribution, we predict that at intermediate times, prior to the full stabilisation of all bubbles, the distribution breaks up into a bimodal one. However, the effect is transient and a unimodal final bubble size distribution is recovered, when all the bubbles are stabilised by the particles.

  14. Dynamic modelling of an adsorption storage tank using a hybrid approach combining computational fluid dynamics and process simulation

    USGS Publications Warehouse

    Mota, J.P.B.; Esteves, I.A.A.C.; Rostam-Abadi, M.

    2004-01-01

    A computational fluid dynamics (CFD) software package has been coupled with the dynamic process simulator of an adsorption storage tank for methane fuelled vehicles. The two solvers run as independent processes and handle non-overlapping portions of the computational domain. The codes exchange data on the boundary interface of the two domains to ensure continuity of the solution and of its gradient. A software interface was developed to dynamically suspend and activate each process as necessary, and be responsible for data exchange and process synchronization. This hybrid computational tool has been successfully employed to accurately simulate the discharge of a new tank design and evaluate its performance. The case study presented here shows that CFD and process simulation are highly complementary computational tools, and that there are clear benefits to be gained from a close integration of the two. ?? 2004 Elsevier Ltd. All rights reserved.

  15. Minimally Informative Prior Distributions for PSA

    SciTech Connect

    Dana L. Kelly; Robert W. Youngblood; Kurt G. Vedros

    2010-06-01

    A salient feature of Bayesian inference is its ability to incorporate information from a variety of sources into the inference model, via the prior distribution (hereafter simply “the prior”). However, over-reliance on old information can lead to priors that dominate new data. Some analysts seek to avoid this by trying to work with a minimally informative prior distribution. Another reason for choosing a minimally informative prior is to avoid the often-voiced criticism of subjectivity in the choice of prior. Minimally informative priors fall into two broad classes: 1) so-called noninformative priors, which attempt to be completely objective, in that the posterior distribution is determined as completely as possible by the observed data, the most well known example in this class being the Jeffreys prior, and 2) priors that are diffuse over the region where the likelihood function is nonnegligible, but that incorporate some information about the parameters being estimated, such as a mean value. In this paper, we compare four approaches in the second class, with respect to their practical implications for Bayesian inference in Probabilistic Safety Assessment (PSA). The most commonly used such prior, the so-called constrained noninformative prior, is a special case of the maximum entropy prior. This is formulated as a conjugate distribution for the most commonly encountered aleatory models in PSA, and is correspondingly mathematically convenient; however, it has a relatively light tail and this can cause the posterior mean to be overly influenced by the prior in updates with sparse data. A more informative prior that is capable, in principle, of dealing more effectively with sparse data is a mixture of conjugate priors. A particular diffuse nonconjugate prior, the logistic-normal, is shown to behave similarly for some purposes. Finally, we review the so-called robust prior. Rather than relying on the mathematical abstraction of entropy, as does the constrained

  16. Mutational analysis of photosystem I polypeptides in the cyanobacterium Synechocystis sp. PCC 6803. Targeted inactivation of psaI reveals the function of psaI in the structural organization of psaL

    NASA Technical Reports Server (NTRS)

    Xu, Q.; Hoppe, D.; Chitnis, V. P.; Odom, W. R.; Guikema, J. A.; Chitnis, P. R.; Spooner, B. S. (Principal Investigator)

    1995-01-01

    We cloned, characterized, and inactivated the psaI gene encoding a 4-kDa hydrophobic subunit of photosystem I from the cyanobacterium Synechocystis sp. PCC 6803. The psaI gene is located 90 base pairs downstream from psaL, and is transcribed on 0.94- and 0.32-kilobase transcripts. To identify the function of PsaI, we generated a cyanobacterial strain in which psaI has been interrupted by a gene for chloramphenicol resistance. The wild-type and the mutant cells showed comparable rates of photoautotrophic growth at 25 degrees C. However, the mutant cells grew slower and contained less chlorophyll than the wild-type cells, when grown at 40 degrees C. The PsaI-less membranes from cells grown at either temperature showed a small decrease in NADP+ photoreduction rate when compared to the wild-type membranes. Inactivation of psaI led to an 80% decrease in the PsaL level in the photosynthetic membranes and to a complete loss of PsaL in the purified photosystem I preparations, but had little effect on the accumulation of other photosystem I subunits. Upon solubilization with nonionic detergents, photosystem I trimers could be obtained from the wild-type, but not from the PsaI-less membranes. The PsaI-less photosystem I monomers did not contain detectable levels of PsaL. Therefore, a structural interaction between PsaL and PsaI may stabilize the association of PsaL with the photosystem I core. PsaL in the wild-type and PsaI-less membranes showed equal resistance to removal by chaotropic agents. However, PsaL in the PsaI-less strain exhibited an increased susceptibility to proteolysis. From these data, we conclude that PsaI has a crucial role in aiding normal structural organization of PsaL within the photosystem I complex and the absence of PsaI alters PsaL organization, leading to a small, but physiologically significant, defect in photosystem I function.

  17. Prostate Cancer Screening: Should You Get a PSA Test?

    MedlinePlus

    ... Whether you're taking medications that affect PSA measurements, such as finasteride (Propecia, Proscar), dutasteride (Avodart) and ... in the United States, 2015: A review of current American Cancer Society guidelines and current issues in ...

  18. [Alternative tests to PSA for prostate cancer diagnosis].

    PubMed

    Defilippi, Elio; Zitella, Andrea; Tizzani, Alessandro

    2011-01-01

    Prostate specific antigen (PSA) is still the most useful tool to select the population requiring prostatebiopsy. The main downsides of PSA are an inadequate sensitivity to be used in screening and a low specificity for cancer detection. So far, a limited value for PSA derivates (velocity, density, free, proisoforms and doubling time) has been recognised. We present a short review of the literature describing a selection of the most promising alternatives to PSA being studied currently: PCA3, serum kallikreins, serum detectable prostate specific membrane antigen, the nuclear matrix protein EPCA, EPCA-2, prostatic acid phosphatase, urine detectable GSTP1, anti-AMACR antibodies, sarcosine, plasminogen activating urokinase, IGFBP, TGF beta 1,PSP94, IL6, plasmatic DNA, serum autoantibodies, neuroendocrine markers, proteomic analysis.

  19. PSA Velocity Does Not Improve Prostate Cancer Detection

    Cancer.gov

    A rapid increase in prostate-specific antigen (PSA) levels is not grounds for automatically recommending a prostate biopsy, according to a study published online February 24, 2011, in the Journal of the National Cancer Institute.

  20. Adsorption studies on wastewaters from cypermethrin manufacturing process using activated coconut shell carbon.

    PubMed

    Bhuvaneswari, K; Ravi Prasad, P; Sarma, P N

    2007-10-01

    Cypermethrin is a pyrethroid pesticide and is used in the control of a wide range of insects on crops like vegetables, cereals, maize etc. In the present study, the adsorption efficiency of coconut shell based activated carbon for the removal of color and organic matter from cypermethrin pesticide manufacturing industrial wastewater was investigated. Effect of carbon dosage, pH and contact time on the removal of COD was also studied. Equilibrium and kinetic studies were carried out and the data was fitted in Freundlich and Langmuir models. The study proved that activated coconut shell carbon (acc) is an efficient adsorbent for treatment of cypermethrin industrial wastewaters under study.

  1. Optimized design of PSA nitrogen-manufacturing system based on PLC

    NASA Astrophysics Data System (ADS)

    Nie, Zongyao; Ma, Xiushui; Jiang, Jun

    2010-12-01

    Firstly introducing principle and technological process of PSA nitrogen-manufacturing system, on condition of its high air consumption and weak in nitrogen-manufacturing system at present. We repeatedly studied the controlled object in this process, analyzed the PLC procedure based on the program rule of PLC of Siemens S7-200 series, then re-program PLC procedure without altering the nitrogen production technique of PSA nitrogen-manufacturing system. At the same time, in order to improve the operation efficiency of the response of action, we also did experiment and demonstration in the consistency of the I/O port and peripheral equipment. In this paper, through optimization of hardware and software design, the nitrogen producing cost was calculated at RMB 0.35 per m3, declined by 12% from the original RMB 0.4 per m3.

  2. Optimized design of PSA nitrogen-manufacturing system based on PLC

    NASA Astrophysics Data System (ADS)

    Nie, Zongyao; Ma, Xiushui; Jiang, Jun

    2011-05-01

    Firstly introducing principle and technological process of PSA nitrogen-manufacturing system, on condition of its high air consumption and weak in nitrogen-manufacturing system at present. We repeatedly studied the controlled object in this process, analyzed the PLC procedure based on the program rule of PLC of Siemens S7-200 series, then re-program PLC procedure without altering the nitrogen production technique of PSA nitrogen-manufacturing system. At the same time, in order to improve the operation efficiency of the response of action, we also did experiment and demonstration in the consistency of the I/O port and peripheral equipment. In this paper, through optimization of hardware and software design, the nitrogen producing cost was calculated at RMB 0.35 per m3, declined by 12% from the original RMB 0.4 per m3.

  3. Naphthenic acids speciation and removal during petroleum-coke adsorption and ozonation of oil sands process-affected water.

    PubMed

    Gamal El-Din, Mohamed; Fu, Hongjing; Wang, Nan; Chelme-Ayala, Pamela; Pérez-Estrada, Leonidas; Drzewicz, Przemysław; Martin, Jonathan W; Zubot, Warren; Smith, Daniel W

    2011-11-01

    The Athabasca Oil Sands industry produces large volumes of oil sands process-affected water (OSPW) as a result of bitumen extraction and upgrading processes. Constituents of OSPW include chloride, naphthenic acids (NAs), aromatic hydrocarbons, and trace heavy metals, among other inorganic and organic compounds. To address the environmental issues associated with the recycling and/or safe return of OSPW into the environment, water treatment technologies are required. This study examined, for the first time, the impacts of pretreatment steps, including filtration and petroleum-coke adsorption, on ozonation requirements and performance. The effect of the initial OSPW pH on treatment performance, and the evolution of ozonation and its impact on OSPW toxicity and biodegradability were also examined. The degradation of more than 76% of total acid-extractable organics was achieved using a semi-batch ozonation system at a utilized ozone dose of 150 mg/L. With a utilized ozone dose of 100 mg/L, the treated OSPW became more biodegradable and showed no toxicity towards Vibrio fischeri. Changes in the NA profiles in terms of carbon number and number of rings were observed after ozonation. The filtration of the OSPW did not improve the ozonation performance. Petroleum-coke adsorption was found to be effective in reducing total acid-extractable organics by a 91%, NA content by an 84%, and OSPW toxicity from 4.3 to 1.1 toxicity units. The results of this study indicate that the combination of petroleum-coke adsorption and ozonation is a promising treatment approach to treat OSPW.

  4. Adsorption-regeneration by heterogeneous Fenton process using modified carbon and clay materials for removal of indigo blue.

    PubMed

    Almazán-Sánchez, Perla Tatiana; Solache-Ríos, Marcos J; Linares-Hernández, Ivonne; Martínez-Miranda, Verónica

    2016-01-01

    Indigo blue dye is mainly used in dyeing of denim clothes and its presence in water bodies could have adverse effects on the aquatic system; for this reason, the objective of this study was to promote the removal of indigo blue dye from aqueous solutions by iron and copper electrochemically modified clay and activated carbon and the saturated materials were regenerated by a Fenton-like process. Montmorillonite clay was modified at pH 2 and 7; activated carbon at pH 2 and pH of the system. The elemental X-ray dispersive spectroscopy analysis showed that the optimum pH for modification of montmorillonite with iron and copper was 7 and for activated carbon was 2. The dye used in this work was characterized by infrared. Unmodified and modified clay samples showed the highest removal efficiencies of the dye (90-100%) in the pH interval from 2 to 10 whereas the removal efficiencies decrease as pH increases for samples modified at pH 2. Unmodified clay and copper-modified activated carbon at pH 2 were the most efficient activated materials for the removal of the dye. The adsorption kinetics data of all materials were best adjusted to the pseudo-second-order model, indicating a chemisorption mechanism and the adsorption isotherms data showed that the materials have a heterogeneous surface. The iron-modified clay could be regenerated by a photo-Fenton-like process through four adsorption-regeneration cycles, with 90% removal efficiency.

  5. Thermal resistance in a single particle of adsorbent for adsorption process

    SciTech Connect

    Tokita, Y.; Sonda, E.; Izumi, J.; Yamada, A.; Yasutake, A.

    1999-07-01

    In the present study, an attempt is made to look into the mechanism of thermal diffusion in a porous adsorbent particle and to measure the dynamic parameters by analysis of breakthrough curves. The adsorbent used in this experiment was an alumina particle with the average diameter of the particle was 6.2 mm. K-type thermocouples were used to measure temperature of a particle, in the core and on the surface. In the experiment, the sample gas (12% CO{sub 2}, Balance N{sub 2}) from a cylinder was introduced into the adsorption section where the alumina particles were exposed to a step change in sorbate concentration. The temperature changes of particle were recorded on a recorder by amplifying the output of the thermocouple with a multimeter. The concentration is intermittently measured at the outlet of the adsorbent section by Gas Chromatography. The experiment ends when the outlet concentration equals to the inlet concentration, meaning that equilibrium has been achieved. This study may give insight into the mechanism of adsorption phenomena and provide also an available means of improving the performance of adsorbent.

  6. Analysis and treatment of industrial wastewater through chemical coagulation-adsorption process-A case study of Clariant Pakistan limited

    NASA Astrophysics Data System (ADS)

    Ali Shah, Syed Farman; Shah, Abdul Karim; Mehdi, Ahmad; Memon, Aziza Aftab; Harijan, Khanji; Ali, Zeenat M.

    2012-05-01

    Textile dye manufacture processes are known as the most polluting chemical processes of industrial sectors of the world. Colored wastewaters along with many polluting agents are troublesome. They are heavily polluted with dyes, textile auxiliaries and chemicals. Current study applies a coupled technology for wastewater treatment. Combined coagulation-adsorption process was utilized for treatment of complex nature effluents of dyes, binder emulsion, pigments and textile chemicals plants at Clariant Pakistan. Cost effective coagulant and adsorbent was selected by using waste material from a power generation unit of Water and Power Development Authority (WAPDA), Pakistan. The treated effluent could be reused. Alum+ Activated Carbon, Ferrous sulfate+ Activated Carbon, Ferric chloride + Activated Carbon. Almost complete decolourization was achieved along with reduction in COD up to 65%. Pre and post treatment, TDS, COD, Turbidity and suspended solids were improved.

  7. Recovery of lignocelluloses from pre-hydrolysis liquor in the lime kiln of kraft-based dissolving pulp production process by adsorption to lime mud.

    PubMed

    Shen, Jing; Fatehi, Pedram; Soleimani, Pendar; Ni, Yonghao

    2011-11-01

    Dissolved lignocelluloses from the pre-hydrolysis liquor (PHL) of kraft-based dissolving pulp production process were recovered by adsorption to lime mud produced in the causticizing plant of the kraft process. The adsorption of lignocelluloses was a fast process, and could be completed within one hour. The addition of polydiallyldimethylammonium chloride (PDADMAC) significantly increased the amounts of adsorbed lignin and hemicelluloses, which more than doubled at the PDADMAC dosage of 0.1% (based on the weight of PHL). The measured heating values of the adsorbed lignocelluloses indicate that adsorption of lignocelluloses to lime mud may result in the energy saving of the lime kiln. The process proposed in this study could also be adapted to decrease inhibitor concentrations (lignin and acetic acid) if the dissolved hemicelluloses in the PHL were used to produce value-added products, e.g., ethanol, xylitol, based on the fermentation process.

  8. Wastewater from wood and pulp industry treated by combination of coagulation, adsorption on modified clinoptilolite tuff and membrane processes.

    PubMed

    Bennani, Yasmina; Kosutić, Kresimir; Drazević, Emil; Rozeć, Mirela

    2012-06-01

    Wastewater from the wood and pulp industry is of environmental concern. It contains high concentrations of organic and inorganic matter. In this work a combined method of coagulation, adsorption and nanofiltration/reverse osmosis (NF/RO) was investigated in the purification of biologically treated wastewater from wood processing. Coagulation with 0.8 g dm(-3) AlCl3 x 6H2O and adsorption on 2.5 g m(-3) modified clinoptilolite tuff resulted in removal efficiencies of total carbon (TC), total organic carbon (TOC) and inorganic carbon (IC) up to 67.1%, 77.4% and 49.5%, respectively. Almost complete removal of solutes was achieved after NF/RO treatment. The TOC removal efficiency with RO membrane (CPA-3, LFC-1, XLE) and tight NF membrane (NF90) was 98% and with highly porous NF membrane (DK), 88%. After the proposed treatment the purified water stream can be recycled into the process or safely disposed to the river.

  9. [Measurement of serum PSA by DELFIA PSA kit and its application for mass screening. The Gunma Urological Oncology Study Group].

    PubMed

    Imai, K; Watanabe, K; Higashi, H; Shinya, H; Okamura, K; Matsuo, Y; Yazima, H; Takezawa, Y; Yamanaka, H

    1993-09-01

    The significance of prostate specific antigen (PSA) measured by DELFIA PSA kit in the 1,177 serum samples examined by mass screening for prostate cancer was evaluated. All subjects were examined by questionnaire, digital rectal examination (DRE) and prostatic acid phosphatase (PAP) and the subjects in whom prostate cancer was suspected from abnormal DRE and/or elevated PAP were recommended to receive the secondary screening for the presence of prostate cancer. All serum specimens used for this study were kept in our serum bank. The cut-off value was investigated between non-cancer subjects (diagnosed as normal, voiding disturbance or BPH) and prostate cancer patients. When the cut-off value was 2.89 ng/ml, the sensitivity, specificity and accuracy as prostate marker was 80.6%, 90.0% and 89.4%, respectively. Therefore, the cut-off value was determined as 3.0 ng/ml. The significance of PSA was retrospectively evaluated compared to PAP in the subjects examined by our mass screening. Twenty eight of the 39 palpable prostate cancers which could not be detected from the PAP level were detected from the PSA level, namely the sensitivity of the detection using the PSA level is more excellent than that using PAP. However, the false negative rate obtained using PSA was high (30.3%) in the patients with stage B disease. The relationship among serum PSA concentration, prostate size estimated by DRE and age was investigated. PSA was increased with age and prostate size. This estimation should be confirmed by using an ultrasonography because the prostate size obtained by DRE is inaccurate as compared with that obtained by ultrasonography.

  10. Sensitive detection and glycoprofiling of a prostate specific antigen (PSA) using impedimetric assays

    PubMed Central

    Pihíková, D; Belický, Š; Kasák, P; Bertok, T; Tkac, J

    2016-01-01

    The study presents proof-of-concept for development of an impedimetric biosensor for ultrasensitive glycoprofiling of PSA. The biosensor exhibits three unique characteristics: 1) analysis of PSA with LOD down to 4 aM; 2) analysis of a glycan part of PSA with LOD down to 4 aM level and 3) both assays (i.e. PSA quantification and PSA glycoprofiling) can be performed on the same interface due to label-free format of analysis. PMID:26647853

  11. Comprehensive reuse of drinking water treatment residuals in coagulation and adsorption processes.

    PubMed

    Jung, Kyung-Won; Hwang, Min-Jin; Park, Dae-Seon; Ahn, Kyu-Hong

    2016-10-01

    While drinking water treatment residuals (DWTRs) inevitably lead to serious problems due to their huge amount of generation and limitation of landfill sites, their unique properties of containing Al or Fe contents make it possible to reuse them as a beneficial material for coagulant recovery and adsorbent. Hence, in the present study, to comprehensively handle and recycle DWTRs, coagulant recovery from DWTRs and reuse of coagulant recovered residuals (CRs) were investigated. In the first step, coagulant recovery from DWTRs was conducted using response surface methodology (RSM) for statistical optimization of independent variables (pH, solid content, and reaction time) on response variable (Al recovery). As a result, a highly acceptable Al recovery of 97.5 ± 0.4% was recorded, which corresponds to 99.5% of the predicted Al recovery. Comparison study of recovered and commercial coagulant from textile wastewater treatment indicated that recovered coagulant has reasonable potential for use in wastewater treatment, in which the performance efficiencies were 68.5 ± 2.1% COD, 97.2 ± 1.9% turbidity, and 64.3 ± 1.0% color removals at 50 mg Al/L. Subsequently, in a similar manner, RSM was also applied to optimize coagulation conditions (Al dosage, initial pH, and reaction time) for the maximization of real cotton textile wastewater treatment in terms of COD, turbidity, and color removal. Overall performance revealed that the initial pH had a remarkable effect on the removal performance compared to the effects of other independent variables. This is mainly due to the transformation of metal species form with increasing or decreasing pH conditions. Finally, a feasibility test of CRs as adsorbent for phosphate adsorption from aqueous solution was conducted. Adsorption equilibrium of phosphate at different temperatures (10-30 °C) and initial levels of pH (3-11) indicated that the main mechanisms of phosphate adsorption onto CRs are endothermic and chemical

  12. Adsorption of acid-extractable organics from oil sands process-affected water onto biomass-based biochar: Metal content matters.

    PubMed

    Bhuiyan, Tazul I; Tak, Jin K; Sessarego, Sebastian; Harfield, Don; Hill, Josephine M

    2017-02-01

    The impact of biochar properties on acid-extractable organics (AEO) adsorption from oil sands process-affected water (OSPW) was studied. Biochar from wheat straw with the highest ash content (14%) had the highest adsorption capacity (0.59 mg/g) followed by biochar from pulp mill sludge, switchgrass, mountain pine, hemp shives, and aspen wood. The adsorption capacity had no obvious trend with surface area, total pore volume, bulk polarity and aromaticity. The large impact of metal content was consistent with the carboxylates (i.e., naphthenate species) in the OSPW binding to the metals (mainly Al and Fe) on the carbon substrate. Although the capacity of biochar is still approximately two orders of magnitude lower than that of a commercial activated carbon, confirming the property (i.e., metal content) that most influenced AEO adsorption, may allow biochar to become competitive with activated carbon after normalizing for cost, especially if this cost includes environmental impacts.

  13. Cyber-Physical Security Assessment (CyPSA) Toolset

    SciTech Connect

    Garcia, Luis; Patapanchala, Panini; Zonouz, Saman; Davis, Kate; Davis, Matt; Berthier, Robin; Bamba, Mouna; Soubigou, Olivier; Rayala, Vishnu Priya; Weaver, Gabe; Rogers, Edmond; Bobba, Rakesh; Nicol, David; Sauer, Pete

    2016-08-31

    CyPSA seeks to organize and gain insight into the diverse sets of data that a critical infrastructure provider must manage. Specifically CyPSA inventories, manages, and analyzes assets and relations among those assets. A variety of interfaces are provided. CyPSA inventories assets (both cyber and physical). This may include the cataloging of assets through a common interface. Data sources used to generate a catalogue of assets include PowerWorld, NPView, NMap Scans, and device configurations. Depending upon the role of the person using the tool the types of assets accessed as well as the data sources through which asset information is accessed may vary. CyPSA allows practitioners to catalogue relations among assets and these may either be manually or programmatically generated. For example, some common relations among assets include the following: Topological Network Data: Which devices and assets are connected and how? Data sources for this kind of information include NMap scans, NPView topologies (via Firewall rule analysis). Security Metrics Outputs: The output of various security metrics such as overall exposure. Configure Assets:CyPSA may eventually include the ability to configure assets including relays and switches. For example, a system administrator would be able to configure and alter the state of a relay via the CyPSA interface. Annotate Assets: CyPSA also allows practitioners to manually and programmatically annotate assets. Sources of information with which to annotate assets include provenance metadata regarding the data source from which the asset was loaded, vulnerability information from vulnerability databases, configuration information, and the output of an analysis in general.

  14. Removal of the surfactant sodium dodecylbenzenesulfonate from water by processes based on adsorption/bioadsorption and biodegradation.

    PubMed

    Bautista-Toledo, María Isidora; Rivera-Utrilla, José; Méndez-Díaz, José Diego; Sánchez-Polo, Manuel; Carrasco-Marín, Francisco

    2014-03-15

    This study analyzed the bioadsorption/biodegradation kinetics of the surfactant sodium dodecylbenzenesulfonate (SDBS) on commercial activated carbons and on activated carbons prepared in the laboratory by activation of almond shells. The effect of surface oxygen species on these processes was also investigated by using an activated carbon from almond shells oxidized with H2O2 or HNO3. SDBS removal kinetics followed a first-order kinetic model, with rate constants between 1.25×10(-2) h(-1) and 2.14×10(-2) h(-1). The removal rate constants of total organic carbon (TOC) were also determined, obtaining values ranging between 0.51×10(-2) h(-1) and 1.76×10(-2) h(-1). TOC removal rate constants were lower than SDBS removal rate constants, demonstrating that SDBS is also biodegraded during bioadsorption. Both the inorganic carbon concentration and the colony forming units confirm this biodegradation. The amount of SDBS removed from water varies between 109.0 and 232.3 mg SDBS/g of carbon. When SDBS adsorption on activated carbon is conducted in the presence of bacteria, which is the real situation in water treatment plants, a fraction of bacteria are adsorbed on the surface of activated carbon. A part of the SDBS is removed by adsorption (bioadsorption) and other part by biodegradation.

  15. Preparation and characterization of an anionic dye-polycation molecular films by electrostatic layer-by-layer adsorption process.

    PubMed

    Dey, D; Hussain, S A; Nath, R K; Bhattacharjee, D

    2008-07-01

    This communication reports the formation and characterization of self-assembled films of a low molecular weight anionic dye amaranth and polycation poly(allylamine hydrochloride) (PAH) by electrostatic alternating layer-by-layer (LBL) adsorption. It was observed that there was almost no material loss occurred during adsorption process. The UV-vis absorption and fluorescence spectra of amaranth solution reveal that with the increase in amaranth concentration in solution, the aggregated species starts to dominate over the monomeric species. New aggregated band at 600 nm was observed in amaranth-PAH mixture solution absorption spectrum. A new broad low intense band at the longer wavelength region, in the amaranth-PAH mixture solution fluorescence spectrum was observed due to the closer association of amaranth molecule while tagged into the polymer backbone of PAH and consequent formation of aggregates. The broad band system in the 650-750 nm region in the fluorescence spectra of different layered LBL films changes in intensity distribution among various bands within itself, with changing layer number and at 10 bilayer LBL films the longer wavelength band at 710 nm becomes prominent. Existence of dimeric or higher order n-meric species in the LBL films was confirmed by excitation spectroscopic studies. Almost 45 min was required to complete the interaction between amaranth and PAH molecules in the one-bilayer LBL film.

  16. Preparation and characterization of an anionic dye-polycation molecular films by electrostatic layer-by-layer adsorption process

    NASA Astrophysics Data System (ADS)

    Dey, D.; Hussain, S. A.; Nath, R. K.; Bhattacharjee, D.

    2008-07-01

    This communication reports the formation and characterization of self-assembled films of a low molecular weight anionic dye amaranth and polycation poly(allylamine hydrochloride) (PAH) by electrostatic alternating layer-by-layer (LBL) adsorption. It was observed that there was almost no material loss occurred during adsorption process. The UV-vis absorption and fluorescence spectra of amaranth solution reveal that with the increase in amaranth concentration in solution, the aggregated species starts to dominate over the monomeric species. New aggregated band at 600 nm was observed in amaranth-PAH mixture solution absorption spectrum. A new broad low intense band at the longer wavelength region, in the amaranth-PAH mixture solution fluorescence spectrum was observed due to the closer association of amaranth molecule while tagged into the polymer backbone of PAH and consequent formation of aggregates. The broad band system in the 650-750 nm region in the fluorescence spectra of different layered LBL films changes in intensity distribution among various bands within itself, with changing layer number and at 10 bilayer LBL films the longer wavelength band at 710 nm becomes prominent. Existence of dimeric or higher order n-meric species in the LBL films was confirmed by excitation spectroscopic studies. Almost 45 min was required to complete the interaction between amaranth and PAH molecules in the one-bilayer LBL film.

  17. Application of sludge-based carbonaceous materials in a hybrid water treatment process based on adsorption and catalytic wet air oxidation.

    PubMed

    Julcour Lebigue, Carine; Andriantsiferana, Caroline; N'Guessan Krou; Ayral, Catherine; Mohamed, Elham; Wilhelm, Anne-Marie; Delmas, Henri; Le Coq, Laurence; Gerente, Claire; Smith, Karl M; Pullket, Suangusa; Fowler, Geoffrey D; Graham, Nigel J D

    2010-12-01

    This paper describes a preliminary evaluation of the performance of carbonaceous materials prepared from sewage sludges (SBCMs) in a hybrid water treatment process based on adsorption and catalytic wet air oxidation; phenol was used as the model pollutant. Three different sewage sludges were treated by either carbonisation or steam activation, and the physico-chemical properties of the resultant carbonaceous materials (e.g. hardness, BET surface area, ash and elemental content, surface chemistry) were evaluated and compared with a commercial reference activated carbon (PICA F22). The adsorption capacity for phenol of the SBCMs was greater than suggested by their BET surface area, but less than F22; a steam activated, dewatered raw sludge (SA_DRAW) had the greatest adsorption capacity of the SBCMs in the investigated range of concentrations (<0.05 mol L(-1)). In batch oxidation tests, the SBCMs demonstrated catalytic behaviour arising from their substrate adsorptivity and metal content. Recycling of SA_DRAW in successive oxidations led to significant structural attrition and a hardened SA_DRAW was evaluated, but found to be unsatisfactory during the oxidation step. In a combined adsorption-oxidation sequence, both the PICA carbon and a selected SBCM showed deterioration in phenol adsorption after oxidative regeneration, but a steady state performance was reached after 2 or 3 cycles.

  18. Low temperature adsorption and site-conversion process of CO on the Ni(111) surface

    NASA Astrophysics Data System (ADS)

    Beniya, Atsushi; Isomura, Noritake; Hirata, Hirohito; Watanabe, Yoshihide

    2012-12-01

    Low-temperature (25 K) adsorption states and the site conversion of adsorbed CO between the ontop and the hollow sites on Ni(111) were studied by means of temperature programmed desorption and infrared reflection absorption spectroscopy. The activation energy and pre-exponential factor of desorption were estimated to be 1.2 eV and 2.6 × 1013 s- 1, respectively, in the limit of zero coverage. At low coverage, CO molecules preferentially adsorbed at the hollow sites below 100 K. With increasing temperature, the ontop sites were also occupied. Using a van't Hoff plot, the enthalpy and the entropy differences between the hollow and ontop CO were estimated to be 36 meV and 0.043 meV K- 1, respectively, and the vibrational entropy difference was estimated to be 0.085 meV K- 1. The positive entropy difference was the result of the low-energy frustrated translational mode of the ontop CO, which was estimated to be 4.6 ± 0.3 meV. With the harmonic approximation, the upper limit of the activation energy of site hopping from ontop sites to hollow sites was estimated to be 61 meV. In addition, it was suggested that the activation energy of hollow-to-hollow site hopping via a bridge site was less than 37 meV.

  19. Application of PSA to review and define technical specifications for advanced nuclear power plants

    SciTech Connect

    Kim, I.S.; Samanta, P.K.; Reinhart, F.M.; Wohl, M.L.

    1995-11-01

    As part of the design certification process, probabilistic safety assessments (PSAS) are performed at the design stage for each advanced nuclear power plant. Among other usages, these PSAs are important inputs in defining the Technical Specifications (TSs) for these plants. Knowledge gained from their use in improving the TSs for operating nuclear power plants is providing methods and insights for using PSAs at this early stage. Evaluating the safety or the risk significance of the TSs to be defined for an advanced plant encompasses diverse aspects: (a) determining the basic limiting condition for operation (LCO); (b) structuring conditions associated with the LCO; (c) defining completion times (equivalent to allowed outage times in the TS for conventional plants); and, (d) prescribing required actions to be taken within the specified completion times. In this paper, we consider the use of PSA in defining the TSs for an advanced nuclear plant, namely General Electric`s Advanced Boiling Water Reactor (ABWR). Similar approaches are being taken for ABB-CE`s System 80+ and Westinghouse`s AP-600. We discuss the general features of an advanced reactor`s TS, how PSA is being used in reviewing the TSs, and we give an example where the TS submittal was reviewed using a PSA-based analysis to arrive at the requirements for the plant.

  20. Adsorption/Membrane Filtration as a Contaminant Concentration and Separation Process for Mixed Wastes and Tank Wastes - Final Report

    SciTech Connect

    Benjamin, M.M.

    1999-10-01

    This project was conducted to evaluate novel approaches for removing radioactive strontium (Sr) and cesium (Cs) from the tank wastes. The bulk of the Sr removal research conducted as part of this project investigated adsorption of Sr onto a novel adsorbent known as iron-oxide-coated sand. The second major focus of the work was on the removal of cesium. Since the chemistries of strontium and cesium have little commonality, different materials (namely, cesium scavengers known as hexacyanoferrates, HCFs) were employed in these tests. This study bridged several scientific areas and yielded valuable knowledge for implementing new technological processes. The applicability of the results extends beyond the highly specialized application niches investigated experimentally to other issues of potential interest for EMSP programs (e.g., separation of chromium from a variety of wastes using IOCS, separation of Cs from neutral and acidic wastes with EC-controlled HCFs).

  1. Quantitative analysis of trace chromium in blood samples. Combination of the advanced oxidation process with catalytic adsorptive stripping voltammetry.

    PubMed

    Yong, Li; Armstrong, Kristie C; Dansby-Sparks, Royce N; Carrington, Nathan A; Chambers, James Q; Xue, Zi-Ling

    2006-11-01

    A new method for pretreating blood samples for trace Cr analysis is described. The advanced oxidation process (AOP with H2O2 and 5.5-W UV irradiation for 60 min) is used to remove biological/organic species for subsequent analysis. Prior to the AOP pretreatment, acid (HNO3) is used at pH 3.0 to inhibit the enzyme catalase in the blood samples. Catalytic adsorptive stripping voltammetry at a bismuth film electrode gives a Cr concentration of 6.0 +/- 0.3 ppb in the blood samples. This concentration was confirmed by dry-ashing the blood samples and subsequent analysis by atomic absorption spectroscopy. This current method may be used to monitor chromium, a trace metal in humans, and the efficacy and safety of chromium supplements as adjuvant therapy for diabetes.

  2. Purification of the two major proteins from whey concentrate using a cation-exchange selective adsorption process.

    PubMed

    El-Sayed, Mayyada M H; Chase, Howard A

    2010-01-01

    The packed-bed adsorption and elution of aqueous solutions of whey concentrate powders were investigated at pH 3.7 using a 5-mL SP Sepharose FF column to separate and isolate two major proteins namely, alpha-lactalbumin (ALA) and beta-lactoglobulin (BLG) from these solutions. ALA displaced and eluted BLG from the column in a pure form. Pure ALA could then be eluted with good recovery. A novel consecutive two-stage separation process was developed to separate ALA and BLG from whey concentrate mixtures. Almost all of the BLG in the feed was recovered, with 78% being recovered at 95% purity and a further 20% at 86% purity. In addition, 67% of ALA was recovered, 48% at 54% purity and 19% at 60% purity.

  3. The effect of chars and their water extractable organic carbon (WEOC) fractions on atrazine adsorption-desorption processes

    NASA Astrophysics Data System (ADS)

    Cavoski, I.; Jablonowski, N.; Burauel, P.; Miano, T.

    2012-04-01

    Chars are carbonaceous material produced from different type of biomass by pyrolysis. They are known as highly effective adsorbents for atrazine therefore limiting its degradation and its diffusion into the aqueous phase. The aim of the present work is to study the effects of different chars and char's derived WEOC on atrazine sorption-desorption processes. The five chars been used in this study derived from: 1) fast pyrolysis from hard wood (FP1); 2) flash pyrolysis from soft wood (FP2); 3) slow pyrolysis from deciduous wood (CC); 4) gasification from deciduous wood (GC) and 5) the market, purchased as activated charcoal standard (AC). Short-term batch equilibration tests were conducted to assess the sorption-desorption behavior of 14C-labeled atrazine on the chars, with a special focus on the desorption behavior using successive dilution method with six consecutive desorption step. Chars and their WEOC were physically and chemically characterized. Results demonstrate that biomass and pyrolysis process used to produce chars affect their physical and chemical properties, and atrazine adsorption-desorption behavior. Atrazine desorption resulted from the positive and competitive interactions between WEOC and chars surfaces. WEOC pool play important role in atrazine adsorption-desorption behavior. FP1 and FP2 with higher concentration of WEOC showed higher desorption rates, whereas GC, CC and AC with insignificant WEOC concentration strongly adsorb atrazine with low desorption rates. According to our results, when high WEOC pools chars are concerned, an increase in atrazine desorption can be observed but further studies would help in confirming the present results.

  4. [PSA variations in persons with latent prostate cancer].

    PubMed

    Stamatiou, K; Danciu, M; Karakos, C; Sofras, F

    2008-01-01

    The introduction and common use of serum PSA (Prostate Specific Antigen) has been demonstrated a useful index on latent prostate cancer diagnostic but in the same time has increased surgical intervention on histological forms with no eventual future evolution. Benign comportment of latent carcinomas being well known in advance, we correlated in vitro serum PSA from latent tumors, with the samples from a control group (prostates without signs of malignization). Levels of PSA were slightly elevated compared to age norms, mainly in cases with a large coexistent hypertrophy. Our reduced sample does not stand any statistic analysis, but this observation could eventually explain increased diagnostic and hyper-treatment of non-important carcinomas from a clinical point of view.

  5. PROSTATE CANCER SCREENING: PSA TEST AWARENESS AMONG ADULT MALES.

    PubMed

    Obana, Michael; O'Lawrence, Henry

    2015-01-01

    The overall purpose of this study was to determine whether visits to the doctor in the last 12 months, education level, and annual household income for adult males increased the awareness of prostate-specific antigen (PSA) tests. The effect of these factors for the knowledge of PSA exams was performed using statistical analysis. A retrospective secondary database was utilized for this study using the questionnaire in the California Health Interview Survey from 2009. Based on this survey, annual visits to the doctor, higher educational levels attained, and greater take-home pay were statistically significant and the results of the study were equivalent to those hypothesized. This also reflects the consideration of marketing PSA blood test screenings to those adult males who are poor, uneducated, and do not see the doctor on a consistent basis.

  6. Simulation and optimization of pressure swing adsorption systmes using reduced-order modeling

    SciTech Connect

    Agarwal, A.; Biegler, L.; Zitney, S.

    2009-01-01

    Over the past three decades, pressure swing adsorption (PSA) processes have been widely used as energyefficient gas separation techniques, especially for high purity hydrogen purification from refinery gases. Models for PSA processes are multiple instances of partial differential equations (PDEs) in time and space with periodic boundary conditions that link the processing steps together. The solution of this coupled stiff PDE system is governed by steep fronts moving with time. As a result, the optimization of such systems represents a significant computational challenge to current differential algebraic equation (DAE) optimization techniques and nonlinear programming algorithms. Model reduction is one approach to generate cost-efficient low-order models which can be used as surrogate models in the optimization problems. This study develops a reducedorder model (ROM) based on proper orthogonal decomposition (POD), which is a low-dimensional approximation to a dynamic PDE-based model. The proposed method leads to a DAE system of significantly lower order, thus replacing the one obtained from spatial discretization and making the optimization problem computationally efficient. The method has been applied to the dynamic coupled PDE-based model of a twobed four-step PSA process for separation of hydrogen from methane. Separate ROMs have been developed for each operating step with different POD modes for each of them. A significant reduction in the order of the number of states has been achieved. The reduced-order model has been successfully used to maximize hydrogen recovery by manipulating operating pressures, step times and feed and regeneration velocities, while meeting product purity and tight bounds on these parameters. Current results indicate the proposed ROM methodology as a promising surrogate modeling technique for cost-effective optimization purposes.

  7. Adsorptive separation and photocatalytic degradation of methylene blue dye on titanate nanotube powders prepared by hydrothermal process using metal Ti particles as a precursor.

    PubMed

    Hu, Keshui; Xiao, Xin; Cao, Xiufang; Hao, Rong; Zuo, Xiaoxi; Zhang, Xiaojing; Nan, Junmin

    2011-08-30

    Titanate nanotube powders (TNTPs) with the twofold removal ability, i.e. adsorptive separation and photocatalytic degradation, are synthesized under hydrothermal conditions using metal Ti particles as a precursor in the concentrated alkaline solution, and their morphology, structure, adsorptive and photocatalytic properties are investigated. Under hydrothermal conditions, the titanate nanotubes (TNTs) with pore diameter of 3-4nm are produced on the surface of metal Ti particles, and stacked together to form three-dimensional (3D) network with porous structure. The TNTPs synthesized in the autoclave at 130°C for 24h exhibits a maximum adsorption capability of about 197mg g(-1) in the neutral methylene blue (MB) solution (40mg L(-1)) within 90min, the adsorption process can be described by pseudo second-order kinetics model. Especially, in comparison with the adsorptive and the photocatalytic processes are performed in turn, about 50min can be saved through synchronously utilizing the double removal ability of TNTPs when the removal ratio of MB approaches 95% in MB solution (40mg L(-1)) at a solid-liquid (S/L) ratio of 1:8 under ultraviolet (UV) light irradiation. These 3D TNTPs with the twofold removal properties and easier separation ability for recycling use show promising prospect for the treatment of dye pollutants from wastewaters in future industrial application.

  8. Energetic investigation of the adsorption process of CH4, C2H6 and N2 on activated carbon: Numerical and statistical physics treatment

    NASA Astrophysics Data System (ADS)

    Ben Torkia, Yosra; Ben Yahia, Manel; Khalfaoui, Mohamed; Al-Muhtaseb, Shaheen A.; Ben Lamine, Abdelmottaleb

    2014-01-01

    The adsorption energy distribution (AED) function of a commercial activated carbon (BDH-activated carbon) was investigated. For this purpose, the integral equation is derived by using a purely analytical statistical physics treatment. The description of the heterogeneity of the adsorbent is significantly clarified by defining the parameter N(E). This parameter represents the energetic density of the spatial density of the effectively occupied sites. To solve the integral equation, a numerical method was used based on an adequate algorithm. The Langmuir model was adopted as a local adsorption isotherm. This model is developed by using the grand canonical ensemble, which allows defining the physico-chemical parameters involved in the adsorption process. The AED function is estimated by a normal Gaussian function. This method is applied to the adsorption isotherms of nitrogen, methane and ethane at different temperatures. The development of the AED using a statistical physics treatment provides an explanation of the gas molecules behaviour during the adsorption process and gives new physical interpretations at microscopic levels.

  9. Real-time monitoring on the adsorption process of salicylic acid onto chitosan membrane using dielectric spectroscopy: macroscale concentration polarization and dynamics.

    PubMed

    Li, Yuhong; Gao, Weidong; Zhao, Kongshuang; Yang, Gang; Zhu, Zhonghe; Cui, Rongjing

    2013-03-28

    The adsorption process of salicylic acid (SA) onto chitosan membrane is monitored in real time by the dielectric relaxation spectroscopy (DRS) method. A unique dielectric relaxation, which is related to the macroscale concentration polarization layers (CPLs) in the SA solution caused by the adsorption, is observed. By modeling the measured systems composed of the membrane, the CPLs, and the SA solution, the dielectric spectra are analyzed systematically on the basis of the interfacial polarization theory. The parameters about the constituent phases, i.e., the dielectric constant εm and the conductivity κm of the chitosan membrane, the conductivity distribution (κ1 to κ2), and the thickness dCPL of the CPL, are obtained. The time-dependent εm and κm give insight into the microstate of the chitosan membrane during the adsorption. Furthermore, the time evolution of the conductivity gradient of the CPL, Δκ/dCPL, is combined to interpret the adsorption mechanism. It is suggested that the noninvasive dielectric monitoring may be applied to many adsorption and release processes.

  10. Extending the Range of Organic Compounds that Can Be Destroyed Using the Process of Adsorption Coupled with Electrochemical Regeneration - 13054

    SciTech Connect

    Brown, Nigel; Lodge, Mike; Hilton, Linda; Adams, Alex; Vaudey, Claire-Emilie; Toulemonde, Valerie

    2013-07-01

    The nuclear industry is not a provider of oils and solvents but uses them in motors, equipment and even in chemical processes to extract valuable products. Currently, for old and contaminated oils and solvents, techniques still exist, such as incineration, but not all the oils and solvents are compatible with this technique because the activities of some components inside the oils are too high to be accepted at the incineration facility. For these oils, an alternative technique needs to be found for treatment. A process developed for water treatment using a technique of adsorption coupled with electrochemical regeneration has been investigated to assess its capability to treat these organic wastes. One of the strengths of the process is its flexibility and adaptation to different compositions of oils. This point is important because, in the AREVA case, there are a lot of small volumes of old oils which need to be re-characterized. It takes time and money to do it especially when oils are contaminated; this is one reason why the technique is interesting to investigate. Tests have been performed with different oils coming from different sites to test the feasibility. Results demonstrate the destruction of a range of organics with regeneration energy requirements of 13.4 - 68.7 kWh/l and offer confidence for the future potential of the process. (authors)

  11. Hydrophobic dipeptide crystals: a promising Ag-free class of ultramicroporous materials showing argon/oxygen adsorption selectivity.

    PubMed

    Afonso, R; Mendes, A; Gales, L

    2014-09-28

    The adsorption isotherms of nitrogen, oxygen and argon in four VA-class hydrophobic dipeptides are presented. Isotherms were determined at 5, 20 and 35 °C, for a pressure range of 0-6 bar. Under these conditions, adsorption is still in the Henry region. For all materials and temperatures, the sequence of preferential adsorption is Ar > O2 > N2, a highly abnormal result. At 5 °C, the dipeptide with the smallest pores, VI, has Ar/O2 adsorption equilibrium selectivities up to 1.30, the highest ever measured in Ag-free adsorbents. Gas uptakes, at 1 bar and 20 °C, are ∼0.05 mol kg(-1), very low relative values that are partially explained by the low porosity of the solids (<10%). The significance of these results for the development of new materials for the process of O2 generation by pressure swing adsorption (PSA) is discussed. The results indicate some of the structural and chemical properties that prospective Ag-free adsorbents should have in order to have Ar/O2 selectivity, hydrophobic pores, less than 0.5 nm-wide, and porosity of, at least, 20%.

  12. Endocrine disruptors compounds, pharmaceuticals and personal care products in urban wastewater: implications for agricultural reuse and their removal by adsorption process.

    PubMed

    Grassi, Mariangela; Rizzo, Luigi; Farina, Anna

    2013-06-01

    In the last years, a lot of emerging contaminants, such as, endocrine disruptors compounds (EDCs), pharmaceuticals, and personal care products (PPCPs) have been detected in wastewater. Because of their toxicity and possible adverse effects on the environment and humans, their release from urban wastewater treatment plants (UWWTPs) effluents should be minimized, particularly when a wastewater reuse for crops irrigation is expected. Many processes have been investigated for advanced treatment of UWWTP effluents as well as for emerging contaminant degradation; among these, adsorption process was successfully used to remove EDCs and PPCPs from wastewater. This article shortly reviews EDCs and PPCPs removal from UWWTP effluents by adsorption process using conventional and non-conventional adsorbents. The fate of EDCs and PPCPs in UWWTPs and the implications for agricultural wastewater reuse has been addressed too. In spite of the adsorption process looking to be a valuable alternative to other advanced technologies for the removal of emerging contaminants from wastewater, some gaps still remain to evaluate the actual feasibility at full scale. However, according to a few studies available in scientific literature on the use of both powdered activated carbon and granular activated carbon at full scale, adsorption process by activated carbon is a promising, potentially effective, and economically feasible solution for producing safe wastewater for agricultural reuse.

  13. Association of [-2]proPSA with Biopsy Reclassification During Active Surveillance for Prostate Cancer

    PubMed Central

    Tosoian, Jeffrey J.; Loeb, Stacy; Feng, Zhaoyong; Isharwal, Sumit; Landis, Patricia; Elliot, Debra J.; Veltri, Robert; Epstein, Jonathan I.; Partin, Alan W.; Carter, H. Ballentine; Trock, Bruce; Sokoll, Lori J.

    2014-01-01

    Purpose Previous studies have suggested an association between [-2]proPSA expression and prostate cancer detection. Less is known about the utility of this marker in following prostate cancer patients on active surveillance. Thus, our objective was to examine the relationship between [-2]proPSA and biopsy results in men enrolled in an active surveillance program. Materials and Methods In 167 men from our institutional active surveillance program, we used Cox proportional hazards models to examine the relationship between [-2]proPSA and annual surveillance biopsy results. The outcome of interest was biopsy reclassification (Gleason score ≥7, or >2 positive biopsy cores, or >50% involvement of any core with cancer). We also examined the association of biopsy results with total PSA, %fPSA, [-2]proPSA/%fPSA, and the Beckman Coulter Prostate Health Index [phi=([-2]proPSA/fPSA) x (tPSA)½]. Results While on active surveillance (median time from diagnosis 4.3 years), 63 (37.7%) men demonstrated biopsy reclassification based on the above criteria, including 28 (16.7%) of whom had reclassification based on Gleason score upgrading (Gleason score≥7). Baseline and longitudinal %fPSA, %[-2]proPSA, [-2]proPSA/%fPSA, and phi measurements were significantly associated with biopsy reclassification, and %[-2]proPSA and phi provided the greatest predictive accuracy for high-grade cancer. Conclusions In men on active surveillance, measures based on [-2]proPSA such as phi, appear to provide improved prediction of biopsy reclassification during follow-up. Additional validation is warranted to determine whether clinically useful thresholds can be defined, and to better characterize the role of %[-2]proPSA and phi in conjunction with other markers in monitoring patients enrolled in active surveillance. PMID:22901577

  14. CHEMICAL ANALYSIS OF REVERSE OSMOSIS MEMBRANE AND XAD RESIN ADSORPTION CONCENTRATES OF WATER DISINFECTED BY CHLORINATION OR OZONATION/CHLORINATION PROCESSES

    EPA Science Inventory


    Chemical Analysis of Reverse Osmosis Membrane and XAD Resin Adsorption Concentrates of Water Disinfected by Chlorination or Ozonation/Chlorination Processes.

    J. E. Simmons1, S.D. Richardson2, K.M. Schenck3, T. F. Speth3, R. J. Miltner3 and A. D. Thruston2

    1 NHEE...

  15. Hybrid adsorptive membrane reactor

    NASA Technical Reports Server (NTRS)

    Tsotsis, Theodore T. (Inventor); Sahimi, Muhammad (Inventor); Fayyaz-Najafi, Babak (Inventor); Harale, Aadesh (Inventor); Park, Byoung-Gi (Inventor); Liu, Paul K. T. (Inventor)

    2011-01-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  16. Hybrid adsorptive membrane reactor

    SciTech Connect

    Tsotsis, Theodore T.; Sahimi, Muhammad; Fayyaz-Najafi, Babak; Harale, Aadesh; Park, Byoung-Gi; Liu, Paul K. T.

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  17. Lifestyle and Clinical Health Behaviors and PSA Tests

    ERIC Educational Resources Information Center

    Norris, Cynthia; McFall, Stephanie

    2006-01-01

    This study assessed the association of lifestyle and clinical health behaviors with prostate specific antigen (PSA) tests. The study used cross-sectional data from the 2002 Behavioral Risk Factor Surveillance System (BRFSS). We used Stata 8.0 to take into account the complex sample design in analyses. Both lifestyle and clinical health behaviors…

  18. Processing and Performance of MOF (Metal Organic Framework)-Loaded PAN Nanofibrous Membrane for CO2 Adsorption

    NASA Astrophysics Data System (ADS)

    Wahiduzzaman; Khan, Mujibur R.; Harp, Spencer; Neumann, Jeffrey; Sultana, Quazi Nahida

    2016-04-01

    The objective of this experimental study is to produce a nanofibrous membrane functionalized with adsorbent particles called metal organic framework (MOF) in order to adsorb CO2 from a gas source. Therefore, Polyacrylonitrile (PAN) was chosen as the precursor for nanofibers and HKUST-1, a Cu-based MOF, was chosen as adsorbent. The experimental process consists of electrospinning PAN solution blended with HKUST-1 to produce a nanofibrous mat as working substrates. The fibers were collected in a cylindrical canister model. SEM image of this mat showed nanofibers with the presence of small adsorbent particles, impregnated into the as-spun fibers discretely. To increase the amount of MOF particles for effectual gas adsorption, a secondary solvothermal process of producing MOF particles on the fibers was required. This process consists of multiple growth cycles of HKUST-1 particles by using a sol-gel precursor. SEM images showed uniform distribution of porous MOF particles of 2-4 µm in size on the fiber surface. Energy dispersive spectroscopy report of the fiber confirmed the presence of MOF particles through the identification of characteristic Copper elemental peaks of HKUST-1. To determine the thermal stability of the fibrous membrane, Thermogravimetric analysis of HKUST-1 consisting of PAN fiber was performed where a total weight loss of 40% between 210 and 360 °C was observed, hence proving the high-temperature durability of the synthesized membrane. BET surface area of the fiber membrane was measured as 540.73 m2/g. The fiber membrane was then placed into an experimental test bench containing a mixed gas inflow of CO2 and N2. Using non-dispersive infrared CO2 sensors connected to the inlet and outlet port of the bench, significant reduction of CO2 in concentration was measured. Comparative IR spectroscopic analysis between the gas-treated and gas untreated fiber samples showed the presence of characteristic peak in the vicinity of 2300 and 2400 cm-1 which

  19. Additive Fabrication of Conductive Patterns by a Template Transfer Process Based on Benzotriazole Adsorption As a Separation Layer.

    PubMed

    Chang, Yu; Yang, Zhen-Guo

    2016-06-08

    The traditional subtractive process to fabricate conductive patterns is environmentally harmful, wasteful, and limited in line width. The additive process, including direct printing of conductive paste or ink, direct printing of catalytic ink, laser-induced forward transfer, etc., can solve these problems. However, the current additive process also faces many difficulties such as low electrical and adhesion properties, low pattern thickness, high cost, etc. Benzotriazole (BTA), as widely used corrosion inhibitor, can be adsorbed onto a copper surface. The electroplated copper film on BTA-adsorbed copper foil shows poor adhesion. On the basis of this phenomenon, a novel template transfer process to additively fabricate conductive patterns has been developed. A permeant antiadhesive mask is printed on carrier copper foil, and then, BTA is adsorbed onto the exposed area of the carrier foil, thus forming the template. The template is electroplated to grow conductive patterns in the exposed parts, and then can be adhered to the flexible substrate. The substrate is peeled off, with the transfer of the conductive patterns to the substrate, to form the designed conductive patterns on PET. By reimmersing the template into BTA solution, the template can be used again. The mechanism of BTA adsorption and the reason for the low peeling strength are researched using Raman spectra, XPS and electrochemical impedance spectroscopy. Copper patterns more than 20 μm in thickness can be prepared on PET, the resistivity of the prepared copper patterns is 2.01 μΩ cm, which is about the same as bulk copper, and the peeling strength of the pattern on PET is measured to be 6.97 N/cm. This template transfer process, with no waste, low pollution, high electrical and adhesion properties, and low cost, shows high potential in the large scale manufacturing of electronic devices, such as RFID circuitry, FPCs, etc.

  20. Processing methods, characteristics and adsorption behavior of tire derived carbons: a review.

    PubMed

    Saleh, Tawfik A; Gupta, Vinod Kumar

    2014-09-01

    The remarkable increase in the number of vehicles worldwide; and the lack of both technical and economical mechanisms of disposal make waste tires to be a serious source of pollution. One potential recycling process is pyrolysis followed by chemical activation process to produce porous activated carbons. Many researchers have recently proved the capability of such carbons as adsorbents to remove various types of pollutants including organic and inorganic species. This review attempts to compile relevant knowledge about the production methods of carbon from waste rubber tires. The effects of various process parameters including temperature and heating rate, on the pyrolysis stage; activation temperature and time, activation agent and activating gas are reviewed. This review highlights the use of waste-tires derived carbon to remove various types of pollutants like heavy metals, dye, pesticides and others from aqueous media.

  1. Simultaneous adsorption and biodegradation processes in sequencing batch reactor (SBR) for treating copper and cadmium-containing wastewater.

    PubMed

    Lim, Poh-Eng; Ong, Soon-An; Seng, Chye-Eng

    2002-02-01

    The application of simultaneous adsorption and biodegradation processes in the same reactor is known to be effective in the removal of both biodegradable and non-biodegradable contaminants in various kinds of wastewater. The objective of this study is to evaluate the efficacy of the two processes under sequencing batch reactor (SBR) operation in treating copper and cadmium-containing synthetic wastewater with powdered activated carbon (PAC) as the adsorbent. The SBR systems were operated with FILL, REACT, SETTLE, DRAW and IDLE periods in the ratio of 0.5: 3.5: 1.0: 0.75 :0.25 for a cycle time of 6 h. In the presence of 10 mg/L Cu(II) and 30 mg/L Cd(II), respectively, the average COD removal efficiencies were above 85% with the PAC dosage in the influent solution at 143 mg/L compared to around 60% without PAC addition. Copper(II) was found to exert a more pronounced inhibitory effect on the bioactivity of the microorganisms compared to Cd(II). It was observed that the combined presence of Cu(II) and Cd(II) did not exert synergistic effects on the microorganisms. Kinetic study conducted for the REACT period showed that the addition of PAC had minimized the inhibitory effect of the heavy metals on the bioactivity of microorganisms.

  2. Remaining Life Expectancy Measurement and PSA Screening of Older Men.

    PubMed

    Kotwal, Ashwin A; Mohile, Supriya G; Dale, William

    2012-07-01

    BACKGROUND: Guidelines recommend informed decision-making regarding prostate specific antigen (PSA) screening for men with at least 10 years of remaining life expectancy (RLE). Comorbidity measures have been used to judge RLE in previous studies, but assessments based on other common RLE measures are unknown. We assessed whether screening rates varied based on four clinically relevant RLE measures, including comorbidities, in a nationally-representative, community-based sample. METHODS: Using the National Social Life, Health and Aging Project (NSHAP), we selected men over 65 without prostate cancer (n=709). They were stratified into three RLE categories (0-7 years, 8-12 years, and 13+ years) based on validated measures of comorbidities, self-rated health status, functional status, and physical performance. The independent relationship of each RLE measure and a combined measure to screening was determined using multivariable logistic regressions. RESULTS: Self-rated health (OR = 6.82; p < 0.01) most closely correlated with RLE-based screening, while the comorbidity index correlated the least (OR = 1.50; p = 0.09). The relationship of RLE to PSA screening significantly strengthened when controlling for the number of doctor visits, particularly for comorbidities (OR= 43.6; p < 0.001). Men who had consistent estimates of less than 7 years RLE by all four measures had an adjusted PSA screening rate of 43.3%. CONCLUSIONS: Regardless of the RLE measure used, men who were estimated to have limited RLE had significant PSA screening rates. However, different RLE measures have different correlations with PSA screening. Specific estimates of over-screening should therefore carefully consider the RLE measure used.

  3. The experimental study of a new pressure equalization step in the pressure swing adsorption cycle of a portable oxygen concentrator.

    PubMed

    Li, Jianhua

    2014-01-01

    For portable oxygen concentrator by pressure swing adsorption (PSA) method, its volume, mass, power, oxygen flux and oxygen saving efficiency are the most important parameters which are affected strongly by the PSA cycle. In this paper, we propose a new pressure equalization step to optimize the PSA cycle. According to the experimental results, when the product ends of two beds are connected and the feed gas is switched from the high pressure bed to the low pressure bed during the pressure equalization step, the system has a larger oxygen flux, a less energy consumption and a more simple structure.

  4. EPA/NSF ETV Equipment Verification Testing Plan for the Removal of Volatile Organic Chemical Contaminants by Adsorptive Media Processes

    EPA Science Inventory

    This document is the Environmental Technology Verification (ETV) Technology Specific Test Plan (TSTP) for evaluation of drinking water treatment equipment utilizing adsorptive media for synthetic organic chemical (SOC) removal. This TSTP is to be used within the structure provid...

  5. Production of granular activated carbon from food-processing wastes (walnut shells and jujube seeds) and its adsorptive properties.

    PubMed

    Bae, Wookeun; Kim, Jongho; Chung, Jinwook

    2014-08-01

    Commercial activated carbon is a highly effective absorbent that can be used to remove micropollutants from water. As a result, the demand for activated carbon is increasing. In this study, we investigated the optimum manufacturing conditions for producing activated carbon from ligneous wastes generated from food processing. Jujube seeds and walnut shells were selected as raw materials. Carbonization and steam activation were performed in a fixed-bed laboratory electric furnace. To obtain the highest iodine number, the optimum conditions for producing activated carbon from jujube seeds and walnut shells were 2 hr and 1.5 hr (carbonization at 700 degrees C) followed by 1 hr and 0.5 hr (activation at 1000 degrees C), respectively. The surface area and iodine number of activated carbon made from jujube seeds and walnut shells were 1,477 and 1,184 m2/g and 1,450 and 1,200 mg/g, respectively. A pore-distribution analysis revealed that most pores had a pore diameter within or around 30-40 angstroms, and adsorption capacity for surfactants was about 2 times larger than the commercial activated carbon, indicating that waste-based activated carbon can be used as alternative. Implications: Wastes discharged from agricultural and food industries results in a serious environmental problem. A method is proposed to convert food-processing wastes such as jujube seeds and walnut shells into high-grade granular activated carbon. Especially, the performance of jujube seeds as activated carbon is worthy of close attention. There is little research about the application ofjujube seeds. Also, when compared to two commercial carbons (Samchully and Calgon samples), the results show that it is possible to produce high-quality carbon, particularly from jujube seed, using a one-stage, 1,000 degrees C, steam pyrolysis. The preparation of activated carbon from food-processing wastes could increase economic return and reduce pollution.

  6. Effects of surface treatment and process parameters on immobilization of recombinant yeast cells by adsorption to fibrous matrices.

    PubMed

    Kilonzo, Peter; Margaritis, Argyrios; Bergougnou, Maurice

    2011-02-01

    The effects of surface properties of Saccharomyces cerevisiae strains 468/pGAC9 and 468 on adhesion to polyethyleneimine (PEI) and/glutaraldehyde (GA) pre-treated cotton (CT), polyester (PE), polyester+cotton (PECT), nylon (NL), polyurethane foam (PUF), and cellulose re-enforced polyurethane (CPU) fibers were investigated. Process parameters (circulation velocity, pH, ionic strength, media composition and surfactants) were also examined. 80%, 90%, and 35% of the cells were adsorbed onto unmodified CT, PUF, and PE, respectively. PEI-GA pre-treated CT and alkali treated PE yielded 25% and 60% cell adhesion, respectively. Adsorption rate (K(a)) ranged from 0.06 to 0.17 for CT and 0.06-0.16 for PE at varied pH. Adhesion increased by 15% in the presence of ethanol, low pH and ionic strength, and decreased by 23% in the presence of yeast extract and glucose. Shear flow and 1% Triton X-100 detached 62% and 36% nonviable cells from PE and CT, respectively, suggesting that cell immobilization in fibrous-bed bioreactors can be controlled to optimize cell density for long-term stability.

  7. Laccase immobilized on a PAN/adsorbents composite nanofibrous membrane for catechol treatment by a biocatalysis/adsorption process.

    PubMed

    Wang, Qingqing; Cui, Jing; Li, Guohui; Zhang, Jinning; Li, Dawei; Huang, Fenglin; Wei, Qufu

    2014-03-19

    The treatment of catechol via biocatalysis and adsorption with a commercial laccase immobilized on polyacrylonitrile/montmorillonite/graphene oxide (PAN/MMT/GO) composite nanofibers was evaluated with a homemade nanofibrous membrane reactor. The properties in this process of the immobilized laccase on PAN, PAN/MMT as well as PAN/MMT/GO with different weight ratios of MMT and GO were investigated. These membranes were successfully applied for removal of catechol from an aqueous solution. Scanning electron microscope images revealed different morphologies of the enzyme aggregates on different supports. After incorporation of MMT or MMT/GO, the optimum pH showed an alkaline shift to 4, compared to 3.5 for laccase immobilized on pure PAN nanofibers. The optimum temperature was at 55 °C for all the immobilized enzymes. Besides, the addition of GO improved the operational stability and storage stability. A 39% ± 2.23% chemical oxygen demand (COD) removal from the catechol aqueous solution was achieved. Experimental results suggested that laccase, PAN, adsorbent nanoparticles (MMT/GO) can be combined together for catechol treatment in industrial applications.

  8. Bi-level optimizing control of a simulated moving bed process with nonlinear adsorption isotherms.

    PubMed

    Kim, Kiwoong; Kim, Jin-Il; Park, Hyukmin; Koo, Yoon-Mo; Lee, Kwang Soon

    2011-09-23

    A bi-level optimizing control scheme originally proposed for a simulated moving bed (SMB) with linear isotherms has been extended to an SMB with nonlinear isotherms. Cyclic steady state optimization is performed in the upper level to determine the optimum switching period and time-varying feed/desorbent flow rates, and repetitive model predictive control is run in the lower level for purity regulation, taking the decision variables from the upper level as feed-forward information. Experimental as well as numerical study for an SMB process separating a high-concentration mixture of aqueous L-ribose and L-arabinose solutions showed that the proposed scheme performs satisfactorily against various disturbances. In contrast, an alternative scheme based on an SMB model with linear isotherms showed a limitation in the control performance; this scheme was apt to fail in purity regulation.

  9. Fate and transport with material response characterization of green sorption media for copper removal via adsorption process.

    PubMed

    Chang, Ni-Bin; Houmann, Cameron; Lin, Kuen-Song; Wanielista, Martin

    2016-02-01

    Green adsorption media with the inclusion of renewable and recycled materials can be applied as a stormwater best management practice for copper removal. A green adsorption media mixture composed of recycled tire chunk, expanded clay aggregate, and coconut coir was physicochemically evaluated for its potential use in an upflow media filter. A suite of tests were conducted on the media mixture and the individual media components including studies of particle size distribution, isotherms, column adsorption and reaction kinetics. Isotherm test results revealed that the coconut coir had the highest affinity for copper (q(max) = 71.1 mg g(-1)), and that adsorption was maximized at a pH of 7.0. The coconut coir also performed the best under dynamic conditions, having an equilibrium uptake of 1.63 mg g(-1). FE-SEM imaging found a strong correlation between the porosity of the micro pore structure and the adsorptive capacity. The use of the green adsorption media mixture in isolation or the coconut coir with an expanded clay filtration chamber could be an effective and reliable stormwater best management practice for copper removal.

  10. CONTAMINANT ADSORPTION AND OXIDATION VIA FENTON REACTION

    EPA Science Inventory

    A ground water treatment process is proposed involving two cgemical processes: adsorption and oxidation. Adsorption of an organic compound onto granulated activated carbon (GAC) containing iron conveniently results in immobilizing and concentrating contaminants from the ground w...

  11. Generalized random sequential adsorption

    NASA Astrophysics Data System (ADS)

    Tarjus, G.; Schaaf, P.; Talbot, J.

    1990-12-01

    Adsorption of hard spherical particles onto a flat uniform surface is analyzed by using generalized random sequential adsorption (RSA) models. These models are defined by releasing the condition of immobility present in the usual RSA rules to allow for desorption or surface diffusion. Contrary to the simple RSA case, generalized RSA processes are no longer irreversible and the system formed by the adsorbed particles on the surface may reach an equilibrium state. We show by using a distribution function approach that the kinetics of such processes can be described by means of an exact infinite hierarchy of equations reminiscent of the Kirkwood-Salsburg hierarchy for systems at equilibrium. We illustrate the way in which the systems produced by adsorption/desorption and by adsorption/diffusion evolve between the two limits represented by ``simple RSA'' and ``equilibrium'' by considering approximate solutions in terms of truncated density expansions.

  12. Adsorption of Myoglobin to Cu(II)-IDA and Ni(II)-IDA Functionalized Langmuir Monolayers: Study of the Protein Layer Structure during the Adsorption Process by Neutron and X-Ray Reflectivity

    SciTech Connect

    Kent, M.S.; Yim, H.; Sasaki, D.Y.; Satija, Sushil; Seo, Young-Soo; Majewski, J.

    2010-07-19

    The structure and orientation of adsorbed myoglobin as directed by metal-histidine complexation at the liquid-film interface was studied as a function of time using neutron and X-ray reflectivity (NR and XR, respectively). In this system, adsorption is due to the interaction between iminodiacetate (IDA)-chelated divalent metal ions Ni(II) and Cu(II) and histidine moieties at the outer surface of the protein. Adsorption was examined under conditions of constant area per lipid molecule at an initial pressure of 40 mN/m. Adsorption occurred over a time period of about 15 h, allowing detailed characterization of the layer structure throughout the process. The layer thickness and the in-plane averaged segment volume fraction were obtained at roughly 40 min intervals by NR. The binding constant of histidine with Cu(II)-IDA is known to be about four times greater than that of histidine with Ni(II)-IDA. The difference in interaction energy led to significant differences in the structure of the adsorbed layer. For Cu(II)-IDA, the thickness of the adsorbed layer at low protein coverage was {le} 20 {angstrom} and the thickness increased almost linearly with increasing coverage to 42 {angstrom}. For Ni(II)-IDA, the thickness at low coverage was 38 {angstrom} and increased gradually with coverage to 47 {angstrom}. The in-plane averaged segment volume fraction of the adsorbed layer independently confirmed a thinner layer at low coverage for Cu(II)-IDA. These structural differences at the early stages are discussed in terms of either different preferred orientations for isolated chains in the two cases or more extensive conformational changes upon adsorption in the case of Cu(II)-IDA. Subphase dilution experiments provided additional insight, indicating that the adsorbed layer was not in equilibrium with the bulk solution even at low coverages for both IDA-chelated metal ions. We conclude that the weight of the evidence favors the interpretation based on more extensive

  13. Biosynthesis of bifunctional iron oxyhydrosulfate by Acidithiobacillus ferroxidans and their application to coagulation and adsorption.

    PubMed

    Gan, Min; Song, Zibo; Jie, Shiqi; Zhu, Jianyu; Zhu, Yaowu; Liu, Xinxing

    2016-02-01

    Coagulation and adsorption are important environmental technologies, which were widely applied in water treatment. In this study, a type of villous iron oxyhydrosulfate with low crystallinity, high content iron, sulfate and hydroxyl was synthesized by Acidithiobacillus ferrooxidans, which possessed coagulation and heavy metal adsorption ability simultaneously. The results showed that the Cu(II) adsorption capacity increased within a small range over the pH range of 3.0-5.0 but increased evidently over the range of 6.0-8.0. The maximal Cu(II) adsorption capacity of sample Af and Gf reached 50.97 and 46.08mg/g respectively. The optimum pH for Cr(VI) adsorption was 6.0, and the maximal adsorption capacity reached 51.32 and 59.57mg/g. The Langmuir isotherm can better describe the adsorption behavior of Cr(VI). Coagulation performance of the iron oxyhydrosulfate (Sh) has been significantly enhanced by polysilicic acid (PSA), which was mainly determined by PSA/Sh ratio, pH and coagulant dosage. Coagulation efficiency maintained approximately at 98% when the PSA/Sh ratio ranged from 0.4/0.1 to 1.0/0.1. Polysilicic acid worked efficiently in wide pH range extending, from 2 to 3.5. Coagulation performance improved significantly with the increasing of the coagulant dosage at lower dosage range, while, at higher dosage range, the improvement was not evident even with more coagulant addition.

  14. Type of adsorbent and column height in adsorption process of used cooking oil

    NASA Astrophysics Data System (ADS)

    Hasnelly, Hervelly, Taufik, Yusman; Melany, Ivo Nila

    2015-12-01

    The purpose of this research was to find out the best adsorbent and column height that can adsorb color and soluble impurities substances in used cooking oil. This research was meant for knowledge development of refined cooking oil technology. The used of this research was giving out information on the recycling process of used cooking oil. Research design used 2 × 2 factorial pattern in randomized group design with 6 repetitions. The first factor is adsorbent type (J) that consist of activated carbon (J1) and Zeolit (J2). The second factor is column height (K) with variations of 15 cm (k1) and 20 cm (k2). Chemical analysis parameter are free fatty acid, water content and saponification value. Physical parameter measurement was done on color with Hunter Lab system analysis and viscosity using viscometer method. Chemical analysis result of preliminary research on used cooking oil showed water content of 1,9%, free fatty acid 1,58%, saponification value 130,79 mg KOH/g oil, viscosity 0,6 d Pas and color with L value of -27,60, a value 1,04 and b value 1,54. Result on main research showed that adsorbent type only gave effect on water content whereas column height and its interaction was not gave significant effect on water content. Interaction between adsorbent type (J) and column height (K) gave significant effect to free fatty acid, saponification value, viscosity and color for L, a and b value of recycled cooking oil.

  15. Postradiotherapy PSA nadirs fail to support dose escalation study in patients with pretreatment PSA values < 10 ng/ml.

    PubMed

    Herold, D; Hanks, G; Movsas, B; Hanlon, A

    1997-01-01

    With three-dimensional conformal therapy, doses > 75 Gy have been delivered to the prostate with acceptable levels of morbidity; however, higher doses do appear to increase late gastrointestinal (GI) and genitourinary (GU) morbidity. Because patients with pretreatment prostate-specific antigen (PSA) values < 10 ng/ml can achieve 3-year actuarial bNED control rates of 90% after treatment with external beam radiotherapy to doses < 71 Gy, one might question the need for further dose escalation in this population. In this report, we examined the relationship between dose and PSA nadir for 90 patients with pretreatment PSA values < 10 ng/ml entered into a dose escalation study from March 1987 to October 1992. We wanted to see if nadir response data would predict a different outcome from our 3-year bNED control reports. All patients were treated with external beam radiotherapy to ICRU reporting point doses of 6,598 cGy to 7,895 cGy (median of 7,068 cGy). Minimum follow-up was 36 months (median, 47 months). Seven hundred thirty-nine posttreatment PSA nadir values were analyzed, yielding an average of 8.2 values per patient. Estimates of rates of bNED control and time to reach a posttreatment PSA of 1.0 ng/ml were calculated using the Kaplan-Meier product limit method. The log-rank test was used to evaluate differences in rates according to dose levels. Linear regression and Cox proportional hazard modeling were used to relate dose to bNED control on a continuum. Escalating doses from 66 to 79 Gy failed to increase the percentage of patients achieving nadir values < 1 ng/ml and similarly failed to increase the 3-year actuarial bNED control. Linear regression (P = .81) and the chi-square test of association (P = .23) supported the lack of a dose effect on nadir continuously and categorically, respectively, and the Cox regression model supported the conclusion that dose on a continuum has no effect on bNED control (P = .34). Furthermore, time to reach a posttreatment PSA

  16. TiO₂ incorporated in magnetic mesoporous SBA-15 by a facile inner-pore hydrolysis process toward enhanced adsorption-photocatalysis performances for As(III).

    PubMed

    Yu, Lian; Yang, Xiaofang; Wang, Dongsheng

    2015-06-15

    A facile inner-pore hydrolysis combining solvent evaporation method was used to decorate mesoporous silica, in which γ-Fe2O3 nanoparticles was preloaded onto mesoporous SBA-15 followed by decoration of TiO2 nanoparticles. This decoration process exploited the homogeneous dispersivity of γ-Fe2O3 and TiO2 nanoparticles in/on SBA-15 and inhibit aggregation of γ-Fe2O3 and TiO2 nanoparticles, which in turn leaded to a synergistic photocatalytic oxidation and adsorption of As(III). It was found that the prepared nanocomposites had mesoporous structure, large specific surface area, high pore volume and superparamagetism according to SEM/TEM, N2 adsorption-desorption isotherms, XRD and VSM analysis. Experimental results show that SBA-15/γ-Fe2O3-TiO2 can oxidize As(III) to As(V) efficiently in the photocatalysis reaction. At the same time, As(V) is effectively removed through adsorption by the composites. In addition, with the treatment of alkali solution, As(V) can be easily desorbed from SBA-15/γ-Fe2O3-TiO2. After reusage for 5 times, the composites still retain comparable catalysis and adsorption performance compared with that of first use, revealing the excellent stability of the composites.

  17. The effects of alkalinity and acidity of process water and hydrochar washing on the adsorption of atrazine on hydrothermally produced hydrochar.

    PubMed

    Flora, Justine F R; Lu, Xiaowei; Li, Liang; Flora, Joseph R V; Berge, Nicole D

    2013-11-01

    Hydrothermal carbonization of simulated food waste was performed at 250 °C for 20 h using deionized water (DI) and 0.01 N solutions of HCl, NaCl, and NaOH. The hydrochars produced were washed with acetone and the adsorptive capacity of the washed and unwashed hydrochars for atrazine were characterized. Using a generalized linear model, it was shown that the adsorptive capacity of the washed hydrochar was significantly higher than that of the unwashed hydrochars. The HCl processed unwashed hydrochar has a slightly higher adsorptive capacity compared to the DI processed hydrochar while both the NaOH processed washed and unwashed hydrochars were slightly lower than the corresponding DI processed hydrochars. (13)C solid-state NMR results showed no discernible differences in surface functional groups among the washed hydrochars and among the unwashed hydrochars. A clear decrease in alkyl groups and an increase in aromatic/olefinic-C groups were observed after acetone washing. (1)H liquid-phase NMR showed carbon alkyl chains were present in the acetone wash. Interaction energies calculated using dispersion corrected density functional theory show that atrazine is more strongly adsorbed to surfaces without weakly associated alkyl groups.

  18. Exploring Functional β-Cell Heterogeneity In Vivo Using PSA-NCAM as a Specific Marker

    PubMed Central

    Karaca, Melis; Castel, Julien; Tourrel-Cuzin, Cécile; Brun, Manuel; Géant, Anne; Dubois, Mathilde; Catesson, Sandra; Rodriguez, Marianne; Luquet, Serge; Cattan, Pierre; Lockhart, Brian; Lang, Jochen; Ktorza, Alain

    2009-01-01

    Background The mass of pancreatic β-cells varies according to increases in insulin demand. It is hypothesized that functionally heterogeneous β-cell subpopulations take part in this process. Here we characterized two functionally distinct groups of β-cells and investigated their physiological relevance in increased insulin demand conditions in rats. Methods Two rat β-cell populations were sorted by FACS according to their PSA-NCAM surface expression, i.e. βhigh and βlow-cells. Insulin release, Ca2+ movements, ATP and cAMP contents in response to various secretagogues were analyzed. Gene expression profiles and exocytosis machinery were also investigated. In a second part, βhigh and βlow-cell distribution and functionality were investigated in animal models with decreased or increased β-cell function: the Zucker Diabetic Fatty rat and the 48 h glucose-infused rat. Results We show that β-cells are heterogeneous for PSA-NCAM in rat pancreas. Unlike βlow-cells, βhigh-cells express functional β-cell markers and are highly responsive to various insulin secretagogues. Whereas βlow-cells represent the main population in diabetic pancreas, an increase in βhigh-cells is associated with gain of function that follows sustained glucose overload. Conclusion Our data show that a functional heterogeneity of β-cells, assessed by PSA-NCAM surface expression, exists in vivo. These findings pinpoint new target populations involved in endocrine pancreas plasticity and in β-cell defects in type 2 diabetes. PMID:19440374

  19. Tyrosine-phosphorylated Galectin-3 Protein Is Resistant to Prostate-specific Antigen (PSA) Cleavage*

    PubMed Central

    Balan, Vitaly; Nangia-Makker, Pratima; Kho, Dhong Hyo; Wang, Yi; Raz, Avraham

    2012-01-01

    Galectin-3 is a chimeric carbohydrate-binding protein, which interacts with cell surface carbohydrate-containing molecules and extracellular matrix glycoproteins and has been implicated in various biological processes such as cell growth, angiogenesis, motility, and metastasis. It is expressed in a wide range of tumor cells and is associated with tumor progression. The functions of galectin-3 are dependent on its localization and post-translational modifications such as cleavage and phosphorylation. Recently, we showed that galectin-3 Tyr-107 is phosphorylated by c-Abl; concomitantly, it was also shown that galectin-3 can be cleaved at this site by prostate-specific antigen (PSA), a chymotrypsin-like serine protease, after Tyr-107, resulting in loss of galectin-3 multivalency while preserving its carbohydrate binding activity. Galectin-3 is largely a monomer in solution but may form a homodimer by self-association through its carbohydrate recognition domain, whereas, in the presence of a ligand, galectin-3 polymerizes up to pentamers utilizing its N-terminal domain. Oligomerization is a unique feature of secreted galectin-3, which allows its function by forming ordered galectin-glycan structures, i.e. lattices, on the cell surface or through direct engagement of specific cell surface glycoconjugates by traditional ligand-receptor binding. We questioned whether Tyr-107 phosphorylation by c-Abl affects galectin-3 cleavage by PSA. The data suggest a role for galectin-3 in prostate cells associated with increased activity of c-Abl kinase and loss of phosphatase and tensin homologue deleted on chromosome 10 (PTEN) activity. In addition, the ratio of phosphorylated/dephosphorylated galectin-3 might be used as a complementary value to that of PSA for prognosis of prostate cancer and a novel therapeutic target for the treatment of prostate cancer. PMID:22232548

  20. Adsorption behavior of direct red 80 and congo red onto activated carbon/surfactant: process optimization, kinetics and equilibrium.

    PubMed

    Cheng, Zhengjun; Zhang, Lei; Guo, Xiao; Jiang, Xiaohui; Li, Tian

    2015-02-25

    Adsorptions of congo red and direct red 80 onto activated carbon/surfactant from aqueous solution were optimized. The Box-Behnken design (BBD) has been employed to analyze the effects of concentration of surfactant, temperature, pH, and initial concentration of the dye in the adsorption capacity. Their corresponding experimental data could be evaluated excellently by second order polynomial regression models and the two models were also examined based on the analysis of variance and t test statistics, respectively. The optimum conditions were obtained as follows: Cs=34.10 μM, T=50°C, pH=3.5, and CCR=160 mg/L for the congo red system, and Cs=34.10 μM, T=50°C, pH=6.1, and CDR80=110 mg/L for the direct red 80 system. And in these conditions, the measured experimental maximum adsorption capacities for the congo red and direct red 80 removals were 769.48 mg/g and 519.90 mg/g, which were consistent with their corresponding predicted values, with small relative errors of -2.81% and -0.67%, respectively. The adsorption equilibrium and kinetics for the two dye adsorptions onto AC/DDAC were also investigated. The experimental data were fitted by four isotherm models, and Langmuir model presented the best fit. The kinetic studies indicated that the kinetic data followed the pseudo-second-order model.

  1. Response surface methodological approach for the optimization of adsorption process in the removal of Cr(VI) ions by Cu2(OH)2CO3 nanoparticles

    NASA Astrophysics Data System (ADS)

    Srivastava, Varsha; Sharma, Y. C.; Sillanpää, Mika

    2015-01-01

    Cu2(OH)2CO3 nanoparticles were synthesized and characterized by XRD, TEM, SEM and ATR-FTIR. SEM suggested the porous nature of nanoparticles. BET surface area of nanoparticles was measured to be 87 m2 g-1. Cu2(OH)2CO3 nanoparticles were used as adsorbent for the removal of Cr(VI) ions from aqueous solutions and wastewater of the printing press. The central composite design (CCD) of the response surface methodology was employed to optimize important adsorption parameters viz. initial Cr(VI) concentration, pH and dose. Analysis of variance (ANOVA) of the quadratic model suggested that experimental data were excellently fitted to the quadratic model. Optimum conditions for approximately 99% removal of Cr(VI) from synthetic wastewater were determined to be pH 6.5, initial concentration of 550 mg/L, adsorbent dose 0.69 g. The kinetic data for Cr(VI) adsorption were best fitted to the pseudo second order model. The Langmuir adsorption capacity of the adsorbent was determined as 87.72 mg/g. Thermodynamic analysis revealed that the adsorption process was spontaneous and endothermic. Desorption study confirms its reusability up to four adsorption-desorption cycles. Cu2(OH)2CO3 nanoparticles also showed efficient removal in presence of anions like SO42-, PO43-, NO32- and Cl-. Findings of the present study suggest that Cu2(OH)2CO3 is a suitable adsorbent material for the removal of Cr(VI) from aqueous solutions and wastewater.

  2. Preparation and characterization of a hierarchical porous char from sewage sludge with superior adsorption capacity for toluene by a new two-step pore-fabricating process.

    PubMed

    Kong, Lingjun; Xiong, Ya; Tian, Shuanghong; Luo, Rongshu; He, Chun; Huang, Haibao

    2013-10-01

    A kind of hierarchical porous char (SCCA/Zn) was prepared from sewage sludge by a new two-step pore-fabricating process coupling citric acid (CA) with ZnCl2 in a pyrolysis process. The char was characterized by element analysis, N2-adsorption and mercury intrusion measurement etc. It is found that coupling CA and ZnCl2 can synergistically fabricate pores in the pyrolysis process, resulting in a hierarchical porous char, SCCA/Zn, with the largest SBET of 867.6 m(2) g(-1) due to the fact that the former contributes to the fabrication of macro-pores, which provides more space for fabricating meso- and micro-pores by ZnCl2 activation. Although the SBET of SCCA/Zn was 15% less than that of activated carbon fiber (ACF, SBET=999.5 m(2) g(-1)), SCCA/Zn had a higher toluene adsorption capacity (0.83 g g(-1)) than ACF. The inconsistence between their SBET and adsorption capacity can be ascribed to the strong hydrophobic property of SCCA/Zn.

  3. Free and complexed prostate-specific antigen (PSA) in the early detection of prostate cancer.

    PubMed

    Tello, F L; Prats, C H; González, M D

    2001-02-01

    We evaluated the analytical performance and diagnostic utility of complexed prostate-specific antigen (CPSA) and their ratios, complexed-to-total PSA (C/T PSA) and free-to-complexed PSA (F/C PSA), in comparison with the total PSA (TPSA) and free-to-total PSA ratio (F/T PSA) as means of diagnosing prostate cancer (PC). Samples (n=101) were drawn from men with no evidence of malignancy (n=80) and from men with PC (n=21) at biopsy. For determination of the F/T PSA ratio, the DPC Immulite-2000 method was used; and the Bayer Immuno-1 CPSA and TPSA assays were used to determine the C/T PSA ratio. The Bayer Immuno-1 CPSA assay provides accurate and precise CPSA values in human serum. The performance of the different forms and ratios was compared using receiver operating characteristic curve analysis. CPSA had the greatest area under the curve (AUC, 0.689) although it was not statistically different from the other parameters. A cut-off value of 4.66 ng/ml for CPSA provided a specificity of 38% and a sensitivity of 93%. The F/C PSA ratio maintained a sensitivity of 93% and had an increased specificity of 41%. The measurement of CPSA provides a slight increase in specificity compared with the use of the TPSA in the early detection of prostate cancer.

  4. Adsorption/desorption process of formaldehyde onto iron doped graphene: a theoretical exploration from density functional theory calculations.

    PubMed

    Cortés-Arriagada, Diego; Villegas-Escobar, Nery; Miranda-Rojas, Sebastián; Toro-Labbé, Alejandro

    2017-02-08

    The interaction of formaldehyde (H2CO) onto Fe-doped graphene (FeG) was studied in detail from density functional theory calculations and electronic structure analyses. Our aim was to obtain insights into the adsorption, desorption and sensing properties of FeG towards H2CO, a hazardous organic compound. The adsorption of H2CO was shown to be energetically stable onto FeG, with adsorption energies of up to 1.45 eV and favored in different conformations. This interaction was determined to be mostly electrostatic in nature, where the oxygen plays an important role in this contribution; besides, our quantum molecular dynamics results showed the high stability of the FeG-H2CO interaction at ambient temperature (300 K). All the interactions were determined to be accompanied by an increase in the HOMO-LUMO energy gap with respect to the isolated adsorbent, indicating that FeG is highly sensitive to H2CO with respect to pristine graphene. Finally, it was found that external electric fields of 0.04-0.05 a.u. were able to induce the pollutant desorption from the adsorbent, allowing the adsorbent reactivation for repetitive applications. These results indicate that FeG could be a promising candidate for adsorption/sensing platforms of H2CO.

  5. Characterization of TiO(2)-chitosan/glass photocatalyst for the removal of a monoazo dye via photodegradation-adsorption process.

    PubMed

    Zainal, Zulkarnain; Hui, Lee Kong; Hussein, Mohd Zobir; Abdullah, Abdul Halim; Hamadneh, Imad Moh'd Khair Rashid

    2009-05-15

    In this paper, the newly explored TiO(2)-Chitosan/Glass was suggested as a promising alternative material to conventional means of wastewater treatment. Characterization of TiO(2)-Chitosan/Glass photocatalyst was studied with SEM-EDX, XRD, and Fourier transform infrared spectroscopy (FTIR) analysis. The combination effect of photodegradation-adsorption process for the removal of methyl orange (MO), an acid dye of the monoazo series occur promisingly when four layers of TiO(2)-Chitosan/Glass photocatalyst was used for MO removal. Approximately, 87.0% of total MO removal was achieved. The reactive -NH(2), -OH, and metal oxide contents in the prepared photocatalyst responsible for the photodegradation-adsorption effect were confirmed by FTIR study. Similarly, MO removal behavior was well supported by SEM-EDX and XRD analysis. Significant dependence of MO removal on the TiO(2)-Chitosan loading can be explained in terms of relationship between quantum yield of photocatalytic reactions and photocatalyst structure/activity. Hence, the research work done thus far suggests a new method, having both the advantages of photodegradation-adsorption process in the abatement of various wastewater pollutants.

  6. Adsorption of Organics from Domestic Water Supplies.

    ERIC Educational Resources Information Center

    McGuire, Michael J.; Suffet, Irwin H.

    1978-01-01

    This article discusses the current state of the art of organics removal by adsorption. Various theoretical explanations of the adsorption process are given, along with practical results from laboratory, pilot-scale, and full-scale applications. (CS)

  7. Intermittent Androgen Suppression for Rising PSA Level after Radiotherapy

    PubMed Central

    Crook, Juanita M.; O’Callaghan, Christopher J.; Duncan, Graeme; Dearnaley, David P.; Higano, Celestia S.; Horwitz, Eric M.; Frymire, Eliot; Malone, Shawn; Chin, Joseph; Nabid, Abdenour; Warde, Padraig; Corbett, Thomas; Angyalfi, Steve; Goldenberg, S. Larry; Gospodarowicz, Mary K.; Saad, Fred; Logue, John P.; Hall, Emma; Schellhammer, Paul F.; Ding, Keyue; Klotz, Laurence

    2012-01-01

    BACKGROUND Intermittent androgen deprivation for prostate-specific antigen (PSA) elevation after radiotherapy may improve quality of life and delay hormone resistance. We assessed overall survival with intermittent versus continuous androgen deprivation in a noninferiority randomized trial. METHODS We enrolled patients with a PSA level greater than 3 ng per milliliter more than 1 year after primary or salvage radiotherapy for localized prostate cancer. Intermittent treatment was provided in 8-month cycles, with nontreatment periods determined according to the PSA level. The primary end point was overall survival. Secondary end points included quality of life, time to castration-resistant disease, and duration of nontreatment intervals. RESULTS Of 1386 enrolled patients, 690 were randomly assigned to intermittent therapy and 696 to continuous therapy. Median follow-up was 6.9 years. There were no significant between-group differences in adverse events. In the intermittent-therapy group, full testosterone recovery occurred in 35% of patients, and testosterone recovery to the trial-entry threshold occurred in 79%. Intermittent therapy provided potential benefits with respect to physical function, fatigue, urinary problems, hot flashes, libido, and erectile function. There were 268 deaths in the intermittent-therapy group and 256 in the continuous-therapy group. Median overall survival was 8.8 years in the intermittent-therapy group versus 9.1 years in the continuous-therapy group (hazard ratio for death, 1.02; 95% confidence interval, 0.86 to 1.21). The estimated 7-year cumulative rates of disease-related death were 18% and 15% in the two groups, respectively (P = 0.24). CONCLUSIONS Intermittent androgen deprivation was noninferior to continuous therapy with respect to overall survival. Some quality-of-life factors improved with intermittent therapy. (Funded by the Canadian Cancer Society Research Institute and others; ClinicalTrials.gov number, NCT00003653.) PMID

  8. Inhibition of Pneumococcal Adherence to Human Nasopharyngeal Epithelial Cells by Anti-PsaA Antibodies

    PubMed Central

    Romero-Steiner, Sandra; Pilishvili, Tamar; Sampson, Jacquelyn S.; Johnson, Scott E.; Stinson, Annie; Carlone, George M.; Ades, Edwin W.

    2003-01-01

    The role of pneumococcal (Pnc) surface adhesin A (PsaA) in the adherence of Streptococcus pneumoniae (pneumococcus) to host cells is not well defined. We examined the effect of anti-PsaA antibodies in an inhibition of adherence assay using Detroit 562 nasopharyngeal human epithelial cells. Rabbit polyclonal (Pab) anti-recombinant PsaA (rPsaA) sera, a purified mouse monoclonal antibody (MAb) (MAb 6F62G8E12), and 22 healthy adult sera with known anti-PsaA IgG levels (obtained by enzyme-linked immunosorbent assay) were evaluated for their abilities to inhibit Pnc adherence to confluent monolayers (measured as percent reduction in CFU counts compared to those of uninhibited controls). Pnc adherence was dependent on capsular phenotype (no or low adherence for opaque strains). With an inoculum of 104 to 105 bacteria/well, the mean ± standard deviation count in controls was 163 ± 32 CFU/well for transparent strains. Low adherence was observed for a PsaA-minus mutant even at higher inoculum doses. Mean percent inhibitions of adherence with Pab and MAb were 54 and 50%, respectively. Adult sera showed inhibition in a dose-response fashion with a range of 98 to 8%, depending on the serum anti-PsaA antibody concentration. Absorption of Pab with rPsaA restored Pnc adherence to control levels. Absorption of sera with a PsaA-minus mutant did not result in a significant decrease (P >0.05) of inhibition of adherence activity. Additionally, nearly 100% of Pnc adherence was inhibited by lipidated rPsaA at 2.5 μg/ml. Our data support the argument that PsaA is an adhesin that mediates Pnc adherence to human nasopharyngeal cells. This functional assay may be useful in evaluating antibodies elicited in response to PsaA vaccination. PMID:12626450

  9. FDA Approves Test to Aid Post-PSA Biopsy Decisions | Division of Cancer Prevention

    Cancer.gov

    The Food and Drug Administration (FDA) has approved a test to help men with elevated prostate-specific antigen (PSA) test scores decide whether to have a biopsy to test for prostate cancer. The Access Hybritech p2PSA test is approved for use in men aged 50 or older who have a PSA test score between 4 and 10 ng/ml but who show no signs of cancer during a digital rectal exam. |

  10. Adsorption of carbon monoxide on activated carbon tin ligand

    NASA Astrophysics Data System (ADS)

    Mohamad, A. B.; Iyuke, S. E.; Daud, W. R. W.; Kadhum, A. A. H.; Fisal, Z.; Al-Khatib, M. F.; Shariff, A. M.

    2000-09-01

    Activated carbon was impregnated with 34.57% SnCl 2·2H 2O salt and then dried at 180°C to produce AC-SnO 2 to improve its adsorptive interaction with CO. Besides the fact that activated carbon has its original different pore sizes for normal gas phase CO adsorption (as in the case of pure carbon), the impregnated carbon has additional CO adsorption ability due to the presence of O -(ads) on the active sites. AC-SnO 2 proved to be a superior adsorber of CO than pure carbon when used for H 2 purification in a PSA system. Discernibly, the high adsorptive selectivity of AC-SnO 2 towards gas phase CO portrays a good future for the applicability of this noble adsorbent, since CO has become a notorious threat to the global ecosystem due to the current level of air pollution.

  11. Possibilities for recycling cellulases after use in cotton processing: part I: Effects of end-product inhibition, thermal and mechanical deactivation, and cellulase depletion by adsorption.

    PubMed

    Azevedo, Helena; Bishop, David; Cavaco-Paul, Artur

    2002-04-01

    Preliminary recycling experiments with cellulase enzymes after cotton treatments at 50 degrees C showed that activity remaining in the treatment liquors was reduced by about 80% after five recycling steps. The potential problems of end-product inhibition, thermal and mechanical deactivation, and the loss of some components of the cellulase complex by preferential and or irreversible adsorption to cotton substrates were studied. End-product inhibition studies showed that the build-up of cellobiose and glucose would be expected to cause no more than 40% activity loss after five textile treatment cycles. Thermal and mechanical treatments of cellulases suggested that the enzymes start to be deactivated at 60 degrees C and agitation levels similar to those used in textile processing did not cause significant enzyme deactivation. Analysis of cellulase solutions, by fast protein liquid chromatography, before and after adsorption on cotton fabrics, suggested that the cellobiohydrolase II (Cel6A) content of the cellulase complex was reduced, relative to the other components, by preferential adsorption. This would lead to a marked reduction in activity after several treatment cycles and top-up with pure cellobiohydrolase II would be necessary unless this component is easily recoverable from the treated fabric.

  12. Development of the IPRO-zone for fire PSA and its applications

    SciTech Connect

    Kang, D. I.; Han, S. H.

    2012-07-01

    A PSA analyst has been manually determining fire-induced component failure modes and modeling them into the PSA logics. These can be difficult and time-consuming tasks as they need much information and many events are to be modeled. KAERI has been developing the IPRO-ZONE (interface program for constructing zone effect table) to facilitate fire PSA works for identifying and modeling fire-induced component failure modes, and to construct a one top fire event PSA model. With the output of the IPRO-ZONE, the AIMS-PSA, and internal event one top PSA model, one top fire events PSA model is automatically constructed. The outputs of the IPRO-ZONE include information on fire zones/fire scenarios, fire propagation areas, equipment failure modes affected by a fire, internal PSA basic events corresponding to fire-induced equipment failure modes, and fire events to be modeled. This paper introduces the IPRO-ZONE, and its application results to fire PSA of Ulchin Unit 3 and SMART(System-integrated Modular Advanced Reactor). (authors)

  13. Adsorptive removal of crystal violet dye by a local clay and process optimization by response surface methodology

    NASA Astrophysics Data System (ADS)

    Loqman, Amal; El Bali, Brahim; Lützenkirchen, Johannes; Weidler, Peter G.; Kherbeche, Abdelhak

    2016-12-01

    The current study relates to the removal of a dye [crystal violet (CV)] from aqueous solutions through batch adsorption experiment onto a local clay from Morocco. The clay was characterized by X-ray diffraction, IR spectroscopy, X-ray fluorescence, scanning electron microscope, Brunauer-Emmett-Teller analysis and Fraunhofer diffraction method. The influence of independent variables on the removal efficiency was determined and optimized by response surface methodology using the Box-Behnken surface statistical design. The model predicted maximum adsorption of 81.62% under the optimum conditions of operational parameters (125 mg L-1 initial dye concentration, 2.5 g L-1 adsorbent dose and time of 43 min). Practically, the removal ranges in 27.4-95.3%.

  14. Ammonia stripping, activated carbon adsorption and anaerobic biological oxidation as process combination for the treatment of oil shale wastewater.

    PubMed

    Alexandre, Verônica M F; do Nascimento, Felipe V; Cammarota, Magali C

    2016-10-01

    Anaerobic biodegradability of oil shale wastewater was investigated after the following pretreatment sequence: ammonia stripping and activated carbon adsorption. Anaerobic biological treatment of oil shale wastewater is technically feasible after stripping at pH 11 for reducing the N-NH3 concentration, adsorption with 5 g/L of activated carbon in order to reduce recalcitrance and pH adjustment with CO2 so that the sulphate concentration in the medium remains low. After this pretreatment sequence, it was possible to submit the wastewater without dilution to an anaerobic treatment with 62.7% soluble chemical oxygen demand removal and specific methane production of 233.2 mL CH4STP/g CODremoved.

  15. Liquid-Phase Adsorption Fundamentals.

    ERIC Educational Resources Information Center

    Cooney, David O.

    1987-01-01

    Describes an experiment developed and used in the unit operations laboratory course at the University of Wyoming. Involves the liquid-phase adsorption of an organic compound from aqueous solution on activated carbon, and is relevant to adsorption processes in general. (TW)

  16. Rapid adsorption properties of flower-like BiOI nanoplates synthesized via a simple EG-assisted solvothermal process

    NASA Astrophysics Data System (ADS)

    Zhang, Bin; Ji, Guangbin; Gondal, M. A.; Liu, Yousong; Zhang, Xingmiao; Chang, Xiaofeng; Li, Nianwu

    2013-07-01

    Uniform well-crystallized flower-like BiOI nanoplates contained 3.7 nm mesopores, which may be attributed to the internanosheet spaces of BiOI with maximum pore diameters of about 30 nm, were successfully synthesized via a simple ethylene glycol-assisted solvothermal method. The as-prepared porous BiOI nanoplates exhibited excellent adsorption ability, and the saturated extent of adsorption of BiOI over an RhB solution was as high as 197 mg/g, which is much higher than those for BiOCl and BiOBr prepared via the same method and with a similar surface area. The probable adsorption mechanism could have originated from the interaction between the I atom in BiOI and a proton in RhB at different pH values and temperatures. With visible light irradiation ( λ > 420 nm), 80 % of the RhB was degraded in 4 h, while BiOI still demonstrated reasonably outstanding photocatalytic ability under green light ( λ = 550 ± 15 nm) because of its low-energy gap (1.72 eV). The degradation test for BiOI under irradiation at λ = 550 ± 15 nm is an excellent achievement for field applications because the catalyst can be applied in solar irradiation to remove organic pollutants, which may be of great value BiOI complex.

  17. Efficient utilization of Eucheuma denticulatum hydrolysates using an activated carbon adsorption process for ethanol production in a 5-L fermentor.

    PubMed

    Ra, Chae Hun; Kim, Min Ji; Jeong, Gwi-Taek; Kim, Sung-Koo

    2017-03-01

    A total monosaccharide concentration of 37.8 g/L and 85.9% conversion from total fermentable monosaccharides of 44.0 g/L from 110 g dw/L Eucheuma denticulatum slurry were obtained by thermal acid hydrolysis and enzymatic saccharification. Subsequent adsorption treatment to remove 5-hydroxymethylfurfural (5-HMF) using 5% activated carbon and an adsorption time of 10 min were used to prevent a prolonged lag phase, reduced cell growth, and low ethanol production. The equilibrium adsorption capacity (q e) of HMF (58.183 mg/g) showed high affinity to activated carbon comparing to those of galactose (2.466 mg/g) and glucose (2.474 mg/g). The efficiency of cell growth and ethanol production with activated carbon treatment was higher than that without activated carbon treatment. Fermentation using S. stipitis KCTC7228 produced a cell concentration of 3.58 g dw/L with Y X/S of 0.107, and an ethanol concentration of 15.8 g/L with Y P/S of 0.48 in 96 h.

  18. A combined process of activated carbon adsorption, ion exchange resin treatment and membrane concentration for recovery of dissolved organics in pre-hydrolysis liquor of the kraft-based dissolving pulp production process.

    PubMed

    Shen, Jing; Kaur, Ishneet; Baktash, Mir Mojtaba; He, Zhibin; Ni, Yonghao

    2013-01-01

    To recover dissolved organics in pre-hydrolysis liquor (PHL) of the kraft-based dissolving pulp production process, a new combined process concept of sequential steps of activated carbon adsorption, ion exchange resin treatment, and membrane concentration, was proposed. The removal of lignin in the PHL was achieved in the activated carbon adsorption step, which also facilitates the subsequent operations, such as the membrane filtration and ion exchange resin treatment. The ion exchange resin treatment resulted in the removal/concentration of acetic acid, which opens the door for acetic acid recovery. The membrane filtration is to recover/concentrate the dissolved sugars. The combined process resulted in the production of PHL-based concentrate with relatively high concentration of hemicellulosic sugars, i.e., 22.13%.

  19. Coexistence of adsorption and coagulation processes of both arsenate and NOM from contaminated groundwater by nanocrystallined Mg/Al layered double hydroxides.

    PubMed

    Wu, Xilin; Tan, Xiaoli; Yang, Shitong; Wen, Tao; Guo, Hongli; Wang, Xiangke; Xu, Anwu

    2013-08-01

    In this study, nanocrystallined Mg/Al layered double hydroxides (LDH-CO3) and chloridion intercalated nanocrystallined Mg/Al LDHs (LDH-Cl) were synthesized and used for simultaneous removal of arsenic and natural organic matter (NOM) from contaminated groundwater. Humic acid (HA) was selected as a model compound of NOM. The maximum adsorption capacities of arsenate (As(V)) on LDH-CO3 and LDH-Cl are 44.66 and 88.30 mg/g, respectively, and those of HA on LDH-CO3 and LDH-Cl are 53.16 and 269.24 mg/g, respectively. It was found that more than 98% of arsenic and 94% of NOM were eliminated by LDH-Cl from both arsenic and NOM-rich groundwater, which is used as drinking water in Togtoh County, Inner Mongolia, China. The arsenic concentration declined from 231 to 4 μg/L, which meets the drinking water standard. The adsorption mechanisms were determined by using X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and extended X-ray absorption fine structure spectroscopy techniques (EXAFS). The results showed that the removal of HA was mainly via surface complexation as well as coagulation at the surface of LDHs, while the adsorption of As(V) was mainly via ion-exchange process. The presence of HA exhibited little inhibiting effect on As(V) adsorption by occupying partial binding sites on LDH surfaces. Nevertheless, it could not affect the ion-exchange process of As(V) with the interlayer anions of LDHs. The removal of As(V) and HA can be carried out independently due to the different adsorption mechanisms. By integrating the experimental results, it is clear that LDH-Cl can be potentially used as a cost-effective material for the purification of both arsenic and NOM contaminated groundwater.

  20. African Americans’ Perceptions of PSA Prostate Cancer Screening

    PubMed Central

    Hunter, Jaimie C.; Vines, Anissa I.; Carlisle, Veronica

    2016-01-01

    Background In 2012, the US Preventive Services Task Force (USPSTF) released a hotly-debated recommendation against prostate-specific antigen (PSA) testing for all men. The present research examines African Americans’ beliefs about their susceptibility to prostate cancer (PCa) and the effectiveness of PSA testing in the context of the controversy surrounding this recommendation. Methods This study used a qualitative design to examine perceptions regarding susceptibility along with screening and facilitators of and barriers thereof. Data were collected at a community health center and three predominantly African American churches in North Carolina. Study participants were 46 African American men and women who attended one of four “listening sessions” for pretesting PCa educational materials (average age: 55 years). One-and-a-half-hour listening sessions were conducted to pretest materials; while presenting the materials, researchers probed beliefs and knowledge about PCa screening. The sessions were recorded and transcribed, and the transcripts were qualitatively analyzed using grounded theory. Results The four emergent themes indicated that participants: (1) cited behavioral, psychosocial, and biological reasons why African American men have higher PCa risk compared to others; (2) knew about the controversy and had varying responses and intentions; (3) believed screening could save lives, so it should be utilized regardless of the 2012 recommendation; and (4) felt that women can help men go to the doctor and make screening decisions. Conclusions Health education efforts to help community members understand health controversies, screening options, and how to make informed screening decisions are critical. PMID:25616411

  1. A review on zinc and nickel adsorption on natural and modified zeolite, bentonite and vermiculite: examination of process parameters, kinetics and isotherms.

    PubMed

    Malamis, S; Katsou, E

    2013-05-15

    Adsorption and ion exchange can be effectively employed for the treatment of metal-contaminated wastewater streams. The use of low-cost materials as sorbents increases the competitive advantage of the process. Natural and modified minerals have been extensively employed for the removal of nickel and zinc from water and wastewater. This work critically reviews existing knowledge and research on the uptake of nickel and zinc by natural and modified zeolite, bentonite and vermiculite. It focuses on the examination of different parameters affecting the process, system kinetics and equilibrium conditions. The process parameters under investigation are the initial metal concentration, ionic strength, solution pH, adsorbent type, grain size and concentration, temperature, agitation speed, presence of competing ions in the solution and type of adsorbate. The system's performance is evaluated with respect to the overall metal removal and the adsorption capacity. Furthermore, research works comparing the process kinetics with existing reaction kinetic and diffusion models are reviewed as well as works examining the performance of isotherm models against the experimental equilibrium data.

  2. Kinetic and equilibrium studies for the adsorption process of cadmium(II) and copper(II) onto Pseudomonas aeruginosa using square wave anodic stripping voltammetry method.

    PubMed

    Kong, Bo; Tang, Biyu; Liu, Xiaoying; Zeng, Xiandong; Duan, Haiyan; Luo, Shenglian; Wei, Wanzhi

    2009-08-15

    A novel method for the simultaneous determination of cadmium(II) and copper(II) during the adsorption process onto Pseudomonas aeruginosa was developed. The concentration of the free metal ions was successfully detected by square wave anodic stripping voltammetry (SWASV) on the mercaptoethane sulfonate (MES) modified gold electrode, while the P. aeruginosa was efficiently avoided approaching to the electrode surface by the MES monolayer. And the anodic stripping peaks of Cd(2+) and Cu(2+) appear at -0.13 and 0.34V respectively, at the concentration range of 5-50 microM, the peak currents of SWASV present linear relationships with the concentrations of cadmium and copper respectively. As the determination of Cd(2+) and Cu(2+) was in real time and without pretreatment, the kinetic characteristics of the adsorption process were studied and all the corresponding regression parameters were obtained by fitting the electrochemical experimental data to the pseudo-second-order kinetic model. Moreover, Langmuir and Freundlich models well described the biosorption isotherms. And there were some differences in the amount of metal ion adsorbed at equilibrium (q(e)) and other kinetics parameters when the two ions coexisted were compared with the unaccompanied condition, which were also discussed in this paper. The proposed electrode system provides excellent platform for the simultaneous determination of trace metals in complex biosorption process.

  3. An algorithm for emulsion stability simulations: account of flocculation, coalescence, surfactant adsorption and the process of Ostwald ripening.

    PubMed

    Urbina-Villalba, German

    2009-03-01

    The first algorithm for Emulsion Stability Simulations (ESS) was presented at the V Conferencia Iberoamericana sobre Equilibrio de Fases y Diseño de Procesos [Luis, J.; García-Sucre, M.; Urbina-Villalba, G. Brownian Dynamics Simulation of Emulsion Stability In: Equifase 99. Libro de Actas, 1(st) Ed., Tojo J., Arce, A., Eds.; Solucion's: Vigo, Spain, 1999; Volume 2, pp. 364-369]. The former version of the program consisted on a minor modification of the Brownian Dynamics algorithm to account for the coalescence of drops. The present version of the program contains elaborate routines for time-dependent surfactant adsorption, average diffusion constants, and Ostwald ripening.

  4. Altered glycosylation pattern allows the distinction between prostate-specific antigen (PSA) from normal and tumor origins.

    PubMed

    Peracaula, Rosa; Tabarés, Glòria; Royle, Louise; Harvey, David J; Dwek, Raymond A; Rudd, Pauline M; de Llorens, Rafael

    2003-06-01

    Prostate-specific antigen (PSA) is a glycoprotein secreted by prostate epithelial cells. PSA is currently used as a marker of prostate carcinoma because high levels of PSA are indicative of a tumor situation. However, PSA tests still suffer from a lack of specificity to distinguish between benign prostate hyperplasia and prostate cancer. To determine whether PSA glycosylation could provide a means of differentiating between PSA from normal and tumor origins, N-glycan characterization of PSA from seminal fluid and prostate cancer cells (LNCaP cell line) by sequencing analysis and mass spectrometry was carried out. Glycans from normal PSA (that correspond to low and high pI PSA fractions) were sialylated biantennary complex structures, half of them being disialylated in the low pI PSA fraction and mostly monosialylated in the high pI PSA. PSA from LNCaP cells was purified to homogeneity, and its glycan analysis showed a significantly different pattern, especially in the outer ends of the biantennary complex structures. In contrast to normal PSA glycans, which were sialylated, LNCaP PSA oligosaccharides were all neutral and contained a higher fucose content. In 10-15% of the structures fucose was linked alpha1-2 to galactose, forming the H2 epitope absent in normal PSA. GalNAc was increased in LNCaP glycans to 65%, whereas in normal PSA it was only present in 25% of the structures. These carbohydrate differences allow a distinction to be made between PSA from normal and tumor origins and suggest a valuable biochemical tool for diagnosis and follow-up purposes.

  5. A biodegradable polymeric system for peptide–protein delivery assembled with porous microspheres and nanoparticles, using an adsorption/infiltration process

    PubMed Central

    Alcalá-Alcalá, Sergio; Urbán-Morlán, Zaida; Aguilar-Rosas, Irene; Quintanar-Guerrero, David

    2013-01-01

    A biodegradable polymeric system is proposed for formulating peptides and proteins. The systems were assembled through the adsorption of biodegradable polymeric nanoparticles onto porous, biodegradable microspheres by an adsorption/infiltration process with the use of an immersion method. The peptide drug is not involved in the manufacturing of the nanoparticles or in obtaining the microspheres; thus, contact with the organic solvent, interfaces, and shear forces required for the process are prevented during drug loading. Leuprolide acetate was used as the model peptide, and poly(d,l-lactide-co-glycolide) (PLGA) was used as the biodegradable polymer. Leuprolide was adsorbed onto different amounts of PLGA nanoparticles (25 mg/mL, 50 mg/mL, 75 mg/mL, and 100 mg/mL) in a first stage; then, these were infiltrated into porous PLGA microspheres (100 mg) by dipping the structures into a microsphere suspension. In this way, the leuprolide was adsorbed onto both surfaces (ie, nanoparticles and microspheres). Scanning electron microscopy studies revealed the formation of a nanoparticle film on the porous microsphere surface that becomes more continuous as the amount of infiltrated nanoparticles increases. The adsorption efficiency and release rate are dependent on the amount of adsorbed nanoparticles. As expected, a greater adsorption efficiency (~95%) and a slower release rate were seen (~20% of released leuprolide in 12 hours) when a larger amount of nanoparticles was adsorbed (100 mg/mL of nanoparticles). Leuprolide acetate begins to be released immediately when there are no infiltrated nanoparticles, and 90% of the peptide is released in the first 12 hours. In contrast, the systems assembled in this study released less than 44% of the loaded drug during the same period of time. The observed release profiles denoted a Fickian diffusion that fit Higuchi’s model (t1/2). The manufacturing process presented here may be useful as a potential alternative for formulating

  6. Network commercials promote legal drugs: outnumber anti-drug PSA's 45-to-1.

    PubMed

    Fedler, F; Phillips, M; Raker, P; Schefsky, D; Soluri, J

    1994-01-01

    During the week of September 16 to 22, 1990, commercials promoting drugs and alcohol outnumbered the networks' news stories, documentaries, and PSA's about illegal drugs by a ratio of almost 39-to-1. If you consider the PSA's alone, the commercials promoting drugs and alcohol outnumbered them by a ratio of almost 45-to-1.

  7. Synthesis of PSA Inhibitors as SPECT- and PET-Based Imaging Agents for Prostate Cancer

    DTIC Science & Technology

    2011-06-01

    for their ability to inhibit PSA and chymotrypsin. 15. SUBJECT TERMS Prostate cancer , PSA inhibitors, boronic acids, peptidomimetics, serine protease...prostate cancer . First, all men undergoing androgen ablation, eventually relapse and no longer respond to hormone treatment . Therefore, there is an...Imaging Agents for Prostate Cancer PRINCIPAL INVESTIGATOR: Maya Kostova, Ph.D. CONTRACTING ORGANIZATION: Johns Hopkins University

  8. Distribution of PSA-NCAM in normal, Alzheimer's and Parkinson's disease human brain.

    PubMed

    Murray, Helen C; Low, Victoria F; Swanson, Molly E V; Dieriks, Birger V; Turner, Clinton; Faull, Richard L M; Curtis, Maurice A

    2016-08-25

    Polysialated neural cell adhesion molecule (PSA-NCAM) is a membrane bound glycoprotein widely expressed during nervous system development. While commonly described in the neurogenic niches of the adult human brain, there is limited evidence of its distribution in other brain regions. PSA-NCAM is an important regulator of cell-cell interactions and facilitates cell migration and plasticity. Recent evidence suggests these functions may be altered in neurodegenerative diseases such as Alzheimer's (AD) and Parkinson's disease (PD). This study provides a detailed description of the PSA-NCAM distribution throughout the human brain and quantitatively compares the staining load in cortical regions and sub-cortical structures between the control, AD and PD brain. Our results provide evidence of widespread, yet specific, PSA-NCAM expression throughout the human brain including regions devoid of PSA-NCAM in the rodent brain such as the caudate nucleus (CN) and cerebellum (CB). We also detected a significant reduction in PSA-NCAM load in the entorhinal cortex (EC) of cases that was inversely correlated with hyperphosphorylated tau load. These results demonstrate that PSA-NCAM-mediated structural plasticity may not be limited to neurogenic niches and is conserved in the aged brain. We also provide evidence that PSA-NCAM is reduced in the EC, a region severely affected by AD pathology.

  9. Kinetic and isotherm studies of adsorption and biosorption processes in the removal of phenolic compounds from aqueous solutions: comparative study

    PubMed Central

    2013-01-01

    The phenolic compounds are known by their carcinogenicity and high toxicity as well as creating unpleasant taste and odor in water resources. The present study develops a cost-effective technology for the treatment of water contaminated with phenolic compounds, including Phenol (Ph), 2-chlorophenol (2-CP), and 4-chlorophenol (4-CP). So, two sorbents, rice bran ash (RBA) and biomass of brown algae, Cystoseiraindica, were used and results were compared with the commercially granular activated carbon (GAC). The phenolic compounds were determined using a high performance liquid chromatography (HPLC) under batch equilibrium conditions. The effects of contact time, pH, initial adsorbate concentration, and adsorbent dosages on the removal efficiency were studied. The adsorption data were simulated by isotherm and kinetic models. Results indicated that RBA and GAC had the lowest efficiency for the removal of 2-CP, while the order of removal efficiency for C. indica biomass was as follows: 2-CP > 4-CP > phenol. The efficiency of GAC was higher than those of other adsorbents for all of the phenolic compounds. Furthermore, the adsorption capacity of RBA was found to be higher than that of C. indica biomass. The optimal initial pH for the removal of phenol, 2-CP and 4-CP was determined to be 5, 7, and 7 for RBA, GAC, and algal biomass, respectively. Kinetic studies suggested that the pseudo-second order best fitted the kinetic data. PMID:24355013

  10. Fenton-like processes and adsorption using iron oxide-pillared clay with magnetic properties for organic compound mitigation.

    PubMed

    Tireli, Aline Auxiliadora; Guimarães, Iara do Rosário; Terra, Júlio César de Souza; da Silva, Robson Rosa; Guerreiro, Mário Cesar

    2015-01-01

    In this work, a new step was added to the classic route of iron-pillared clay obtention, resulting in a material with both magnetic and oxidative properties. The saturation of the material surface intercalated with trinuclear acetate-hydroxo iron (III) nitrate in glacial acetic acid atmosphere before heat treatment promoted magnetic phase formation (FePMAG). The material was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS), and X-ray photoelectron spectroscopy (XPS). FePMAG showed an increase of 0.57 nm in basal spacing which contributed to the specific surface area increase from 39.1 to 139.2 m(2)/g. The iron phase identified by XRD and XPS was maghemite, with a little presence of hematite formed by the trinuclear acetate-hydroxo iron (III) nitrate decomposition during heat treatment. In the adsorption tests, FePMAG displayed a good capacity for organic dye methylene blue (MB) removal, reaching 41 % at 150 min. Under photo-Fenton conditions, the material showed an excellent MB oxidation capacity, completely removing the color of the solution within 90 min. Identification of the oxidation products with lower molecular (m/z = 160, 220, and 369) mass was performed by electrospray ionization mass spectroscopy (ESI-MS).

  11. Development of a mixed mode adsorption process for the direct product sequestration of an extracellular protease from microbial batch cultures.

    PubMed

    Hamilton, G E; Luechau, F; Burton, S C; Lyddiatt, A

    2000-04-28

    Direct product sequestration of extracellular proteins from microbial batch cultures can be achieved by continuous or intermittent broth recycle through an external extractive loop. Here, we describe the development of a fluidisable, mixed mode adsorbent, designed to tolerate increasing ionic strength (synonymous with extended productive batch cultures). This facilitated operations for the integrated recovery of an extracellular acid protease from cultures of Yarrowia lipolytica. Mixed mode adsorbents were prepared using chemistries containing hydrophobic and ionic groups. Matrix hydrophobicity and titration ranges were matched to the requirements of integrated protease adsorption. A single expanded bed was able to service the productive phase of growth without recourse to the pH adjustment of the broth previously required for ion exchange adsorption. This resulted in increased yields of product, accompanied by further increases in enzyme specific activity. A step change from pH 4.5 to 2.6, across the isoelectric point of the protease, enabled high resolution fixed bed elution induced by electrostatic repulsion. The generic application of mixed mode chemistries, which combine the physical robustness of ion-exchange ligands in sanitisation and sterilisation procedures with a selectivity, which approaches that of affinity interactions, is discussed.

  12. Activity-dependent PSA expression regulates inhibitory maturation and onset of critical period plasticity.

    PubMed

    Di Cristo, Graziella; Chattopadhyaya, Bidisha; Kuhlman, Sandra J; Fu, Yu; Bélanger, Marie-Claude; Wu, Cai Zhi; Rutishauser, Urs; Maffei, Lamberto; Huang, Z Josh

    2007-12-01

    Functional maturation of GABAergic innervation in the developing visual cortex is regulated by neural activity and sensory inputs and in turn influences the critical period of ocular dominance plasticity. Here we show that polysialic acid (PSA), presented by the neural cell adhesion molecule, has a role in the maturation of GABAergic innervation and ocular dominance plasticity. Concentrations of PSA significantly decline shortly after eye opening in the adolescent mouse visual cortex; this decline is hindered by visual deprivation. The developmental and activity-dependent regulation of PSA expression is inversely correlated with the maturation of GABAergic innervation. Premature removal of PSA in visual cortex results in precocious maturation of perisomatic innervation by basket interneurons, enhanced inhibitory synaptic transmission, and earlier onset of ocular dominance plasticity. The developmental and activity-dependent decline of PSA expression therefore regulates the timing of the maturation of GABAergic inhibition and the onset of ocular dominance plasticity.

  13. Non-Debye relaxation in the dielectric response of nematic liquid crystals: surface and memory effects in the adsorption-desorption process of ionic impurities.

    PubMed

    de Paula, J L; Santoro, P A; Zola, R S; Lenzi, E K; Evangelista, L R; Ciuchi, F; Mazzulla, A; Scaramuzza, N

    2012-11-01

    We demonstrate theoretically that the presence of ions in insulating materials such as nematic liquid crystals may be responsible for the dielectric spectroscopy behavior observed experimentally. It is shown that, at low frequencies, an essentially non-Debye relaxation process takes place due to surface effects. This is accomplished by investigating the effects of the adsorption-desorption process on the electrical response of an electrolytic cell when the generation and recombination of ions is present. The adsorption-desorption is governed by a non-usual kinetic equation in order to incorporate memory effects related to a non-Debye relaxation and the roughness of the surface. The analysis is carried out by searching for solutions to the drift-diffusion equation that satisfy the Poisson equation relating the effective electric field to the net charge density. We also discuss the effect of the mobility of the ions, i.e., situations with equal and different diffusion coefficients for positive and negative ions, on the impedance and obtain an exact expression for the admittance. The model is compared with experimental results measured for the impedance of a nematic liquid crystal sample and a very good agreement is obtained.

  14. Direct observation of the anchoring process during the adsorption of fibrinogen on a solid surface by force-spectroscopy mode atomic force microscopy

    PubMed Central

    Hemmerlé, J.; Altmann, S. M.; Maaloum, M.; Hörber, J. K. H.; Heinrich, L.; Voegel, J.-C.; Schaaf, P.

    1999-01-01

    Atomic force microscopy in a force-spectroscopy mode has been used to investigate the kinetics of the adsorption process of fibrinogen molecules on a silica surface. An original “approach/retraction” cycle of the tip/surface was used for this purpose. Fibrinogen molecules were adsorbed on the atomic force microscopy tip and were brought into contact with the silica surface for different interaction times varying from 5 to 2,000 ms. Multiple consecutive ruptures were observed. The mean number of ruptures nr per cycle increases steadily with the interaction time as well as the mean strength fr which varies from 300 pN for 5 ms to 1,400 pN for 2,000 ms. The minimal interaction time for a fibrinogen molecule to bind strongly to a silica surface during an adsorption process appears to lie between 50 and 200 ms. The histograms of the distances between two consecutive ruptures in one cycle exhibit maxima around 20–25 nm. This length is comparable to the characteristic distance between D and E globules of one fibrinogen molecule and suggests that fibrinogen molecules mainly adsorb through their D and E globules. PMID:10359776

  15. Non-Debye relaxation in the dielectric response of nematic liquid crystals: Surface and memory effects in the adsorption-desorption process of ionic impurities

    NASA Astrophysics Data System (ADS)

    de Paula, J. L.; Santoro, P. A.; Zola, R. S.; Lenzi, E. K.; Evangelista, L. R.; Ciuchi, F.; Mazzulla, A.; Scaramuzza, N.

    2012-11-01

    We demonstrate theoretically that the presence of ions in insulating materials such as nematic liquid crystals may be responsible for the dielectric spectroscopy behavior observed experimentally. It is shown that, at low frequencies, an essentially non-Debye relaxation process takes place due to surface effects. This is accomplished by investigating the effects of the adsorption-desorption process on the electrical response of an electrolytic cell when the generation and recombination of ions is present. The adsorption-desorption is governed by a non-usual kinetic equation in order to incorporate memory effects related to a non-Debye relaxation and the roughness of the surface. The analysis is carried out by searching for solutions to the drift-diffusion equation that satisfy the Poisson equation relating the effective electric field to the net charge density. We also discuss the effect of the mobility of the ions, i.e., situations with equal and different diffusion coefficients for positive and negative ions, on the impedance and obtain an exact expression for the admittance. The model is compared with experimental results measured for the impedance of a nematic liquid crystal sample and a very good agreement is obtained.

  16. Thiobis(hexamethyldisilazane) as a new precursor for the deposition of sulfur on gold: A one-step concerted adsorption process

    NASA Astrophysics Data System (ADS)

    Koczkur, Kallum M.; Houmam, Abdelaziz

    2014-06-01

    Direct experimental evidence for the deposition of sulfur on gold surfaces using thiobis(hexamethyldisilazane) as a new precursor is provided. The modified surfaces are characterized using cyclic voltammetry, X-ray photoelectron spectroscopy, and scanning tunneling microscopy. XPS and electrochemical results show that the modification process is very fast and that high coverage values are reached within a few minutes. The XPS does not show the initial deposition of fragments of thiobis(hexamethyldisilazane) but only shows the deposition of sulfur even after very short modification times. STM results confirm the formation of dense sulfur films and show the formation of the well-known rectangular structures. Images also show the formation of sulfur multilayers. The electrochemical characteristics of the precursor along with its theoretical investigation and the known chemical reactivity of sulfur transfer agents in organic synthesis rule out the dissociative reductive adsorption process. A concerted adsorption mechanism is proposed and is associated with the concerted cleavage of both SN chemical bonds.

  17. A National Multicenter Phase 2 Study of Prostate-specific Antigen (PSA) Pox Virus Vaccine with Sequential Androgen Ablation Therapy in Patients with PSA Progression: ECOG 9802

    PubMed Central

    DiPaola, Robert S.; Chen, Yu-Hui; Bubley, Glenn J.; Stein, Mark N.; Hahn, Noah M.; Carducci, Michael A.; Lattime, Edmund C.; Gulley, James; Arlen, Philip M.; Butterfield, Lisa H.; Wilding, George

    2014-01-01

    Background E9802 was a phase 2 multi-institution study conducted to evaluate the safety and effectiveness of vaccinia and fowlpox prostate-specific antigen (PSA) vaccine (step 1) followed by combination with androgen ablation therapy (step 2) in patients with PSA progression without visible metastasis. Objective To test the hypothesis that vaccine therapy in this early disease setting will be safe and have a biochemical effect that would support future studies of immunotherapy in patients with minimal disease burden. Design, setting, and participants Patients had PSA progression following local therapy were treated with PROSTVAC-V (vaccinia)/TRICOM on cycle 1 followed by PROSTVAC-F (fowlpox)/TRICOM for subsequent cycles in combination with granulocyte-macrophage colony-stimulating factor (step 1). Androgen ablation was added on progression (step 2). Outcome measurements and statistical analysis Step 1 primary end points included progression at 6 mo and characterization of change in PSA velocity pretreatment to post-treatment. Step 2 end points included PSA response with combined vaccine and androgen ablation. Results and limitations In step 1, 25 of 40 eligible patients (63%) were progression free at 6 mo after registration (90% confidence interval [CI], 48–75). The median pretreatment PSA velocity was 0.13 log(PSA)/mo, in contrast to median postregistration velocity of 0.09 log(PSA)/mo (p = 0.02), which is an increase in median PSA doubling time from 5.3 mo to 7.7 mo. No grade ≥4 treatment-related toxicity was observed. In the 27 patients eligible and treated for step 2, 20 patients achieved a complete response (CR) at 7 mo (CR rate: 74%; 90% CI, 57–87). Although supportive of larger studies in the cooperative group setting, this study is limited by the small number of patients and the absence of a control group as in a phase 3 study. Conclusions A viral PSA vaccine can be administered safely in the multi-institutional cooperative group setting to patients

  18. Early Prediction of Therapy Response to Abiraterone Acetate Using PSA Subforms in Patients with Castration Resistant Prostate Cancer

    PubMed Central

    Schlack, Katrin; Krabbe, Laura-Maria; Fobker, Manfred; Schrader, Andres Jan; Semjonow, Axel; Boegemann, Martin

    2016-01-01

    The purpose of this study was to evaluate the prognostic ability of early changes of total prostate specific antigen (tPSA), free PSA (fPSA), [−2]proPSA and the Prostate Health Index (PHI) following initiation of Abiraterone-therapy in men with castration resistant prostate cancer (mCRPC). In 25 patients, PSA-subforms were analyzed before and at 8–12 weeks under therapy as prognosticators of progression-free-survival (PFS) and overall survival (OS). Comparing patients with a PFS < vs. ≥12 months by using Mann–Whitney–Wilcoxon Tests, the relative-median-change of tPSA (−0.1% vs. −86.8%; p = 0.02), fPSA (12.1% vs. −55.3%; p = 0.03) and [−2]proPSA (8.1% vs. −59.3%; p = 0.05) differed significantly. For men with ≤ vs. >15 months of OS there was a non-significant trend for a difference in the relative-median-change of fPSA (17.0% vs. −46.3%; p = 0.06). In Kaplan–Meier analyses, declining fPSA and [−2]proPSA were associated with a longer median PFS (13 months, 95% confidence interval (CI): 9.6–16.4 vs. 10 months, 95% CI: 3.5–16.5; p = 0.11), respectively. Correspondingly, decreasing fPSA and [−2]proPSA values indicated an OS of 32 months (95% CI: not reached (NR)) compared to 21 months in men with rising values (95% CI: 7.7–34.3; p = 0.14), respectively. We concluded that the addition of fPSA- and [−2]proPSA-changes to tPSA-information might be further studied as potential markers of early Abiraterone response in mCRPC patients. PMID:27618028

  19. Early Prediction of Therapy Response to Abiraterone Acetate Using PSA Subforms in Patients with Castration Resistant Prostate Cancer.

    PubMed

    Schlack, Katrin; Krabbe, Laura-Maria; Fobker, Manfred; Schrader, Andres Jan; Semjonow, Axel; Boegemann, Martin

    2016-09-09

    The purpose of this study was to evaluate the prognostic ability of early changes of total prostate specific antigen (tPSA), free PSA (fPSA), [-2]proPSA and the Prostate Health Index (PHI) following initiation of Abiraterone-therapy in men with castration resistant prostate cancer (mCRPC). In 25 patients, PSA-subforms were analyzed before and at 8-12 weeks under therapy as prognosticators of progression-free-survival (PFS) and overall survival (OS). Comparing patients with a PFS < vs. ≥12 months by using Mann-Whitney-Wilcoxon Tests, the relative-median-change of tPSA (-0.1% vs. -86.8%; p = 0.02), fPSA (12.1% vs. -55.3%; p = 0.03) and [-2]proPSA (8.1% vs. -59.3%; p = 0.05) differed significantly. For men with ≤ vs. >15 months of OS there was a non-significant trend for a difference in the relative-median-change of fPSA (17.0% vs. -46.3%; p = 0.06). In Kaplan-Meier analyses, declining fPSA and [-2]proPSA were associated with a longer median PFS (13 months, 95% confidence interval (CI): 9.6-16.4 vs. 10 months, 95% CI: 3.5-16.5; p = 0.11), respectively. Correspondingly, decreasing fPSA and [-2]proPSA values indicated an OS of 32 months (95% CI: not reached (NR)) compared to 21 months in men with rising values (95% CI: 7.7-34.3; p = 0.14), respectively. We concluded that the addition of fPSA- and [-2]proPSA-changes to tPSA-information might be further studied as potential markers of early Abiraterone response in mCRPC patients.

  20. An Algorithm for Emulsion Stability Simulations: Account of Flocculation, Coalescence, Surfactant Adsorption and the Process of Ostwald Ripening

    PubMed Central

    Urbina-Villalba, German

    2009-01-01

    The first algorithm for Emulsion Stability Simulations (ESS) was presented at the V Conferencia Iberoamericana sobre Equilibrio de Fases y Diseño de Procesos [Luis, J.; García-Sucre, M.; Urbina-Villalba, G. Brownian Dynamics Simulation of Emulsion Stability In: Equifase 99. Libro de Actas, 1st Ed., Tojo J., Arce, A., Eds.; Solucion’s: Vigo, Spain, 1999; Volume 2, pp. 364–369]. The former version of the program consisted on a minor modification of the Brownian Dynamics algorithm to account for the coalescence of drops. The present version of the program contains elaborate routines for time-dependent surfactant adsorption, average diffusion constants, and Ostwald ripening. PMID:19399220

  1. Phosphate adsorption on lanthanum loaded biochar.

    PubMed

    Wang, Zhanghong; Shen, Dekui; Shen, Fei; Li, Tianyu

    2016-05-01

    To attain a low-cost and high-efficient phosphate adsorbent, lanthanum (La) loaded biochar (La-BC) prepared by a chemical precipitation method was developed. La-BC and its pristine biochar (CK-BC) were comparatively characterized using zeta potential, BET surface area, scanning electron microscopy/energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The adsorption ability and the mechanisms during adsorption process for the La-BC samples were also investigated. La loaded on the surface of biochar can be termed as La-composites (such as LaOOH, LaONO3 and La(OH)3), leading to the decrease of negative charge and surface area of biochar. La-BC exhibited the high adsorption capacity to phosphate compared to CK-BC. Adsorption isotherm and adsorption kinetic studies showed that the Langmuir isotherm and second order model could well describe the adsorption process of La-BC, indicating that the adsorption was dominated by a homogeneous and chemical process. The calculated maximum adsorption capacity was as high as 46.37 mg g(-1) (computed in P). Thermodynamic analysis revealed that the adsorption was spontaneous and endothermic. SEM, XRD, XPS and FT-IR analysis suggested that the multi-adsorption mechanisms including precipitation, ligand exchange and complexation interactions can be evidenced during the phosphate adsorption process by La-composites in La-BC.

  2. System-dependent dispersion coefficients for the DFT-D3 treatment of adsorption processes on ionic surfaces.

    PubMed

    Ehrlich, Stephan; Moellmann, Jonas; Reckien, Werner; Bredow, Thomas; Grimme, Stefan

    2011-12-09

    Dispersion-corrected density functional theory calculations (DFT-D3) were performed for the adsorption of CO on MgO and C(2) H(2) on NaCl surfaces. An extension of our non-empirical scheme for the computation of atom-in-molecules dispersion coefficients is proposed. It is based on electrostatically embedded M(4)X(4) (M=Na, Mg) clusters that are used in TDDFT calculations of dynamic dipole polarizabilities. We find that the C(MM)(6) dispersion coefficients for bulk NaCl and MgO are reduced by factors of about 100 and 35 for Na and Mg, respectively, compared to the values of the free atoms. These are used in periodic DFT calculations with the revPBE semi-local density functional. As demonstrated by calculations of adsorption potential energy curves, the new C(6) coefficients lead to much more accurate energies (E(ads)) and molecule-surface distances than with previous DFT-D schemes. For NaCl/C(2) H(2) we obtained at the revPBE-D3(BJ) level a value of E(ads) =-7.4 kcal mol(-1) in good agreement with experimental data (-5.7 to -7.1 kcal mol(-1)). Dispersion-uncorrected DFT yields an unbound surface state. For the MgO/CO system, the computed revPBE-D3(BJ) value of E(ads) =-4.1 kcal mol(-1) is also in reasonable agreement with experimental results (-3.0 kcal mol(-1)) when thermal corrections are taken into account. Our new dispersion correction also improves computed lattice constants of the bulk systems significantly compared to plain DFT or previous DFT-D results. The extended DFT-D3 scheme also provides accurate non-covalent interactions for ionic systems without empirical adjustments and is suggested as a general tool in surface science.

  3. Effect of Body mass index on the performance characteristics of PSA-related markers to detect prostate cancer

    PubMed Central

    Zhu, Yao; Han, Cheng-Tao; Zhang, Gui-Ming; Liu, Fang; Ding, Qiang; Xu, Jian-Feng; Vidal, Adriana C.; Freedland, Stephen J.; Ng, Chi-Fai; Ye, Ding-Wei

    2016-01-01

    To examine whether the predictive performance of prostate-specific antigen (PSA) and PSA-related markers for prostate cancer (PCa) is modified by body mass index (BMI). Patients with a PSA 2–10 ng/mL who underwent multicore prostate biopsies were recruited from three tertiary centers. Serum markers measured included total PSA (tPSA), free-to-total PSA (f/tPSA), p2PSA, percentage of p2PSA (%p2PSA), and prostate health index (PHI). The association between serum markers and PCa risk was assessed by logistic regression. Predictive performance for each marker was quantified using the area under the receiver operator curves (AUC). Among 516 men, 18.2% had PCa at biopsy. For all tested markers, their predictive value on PCa risk was lower in obese patients compared to normal weight patients. We found statistically significant interactions between BMI and tPSA (P = 0.0026) and p2PSA (P = 0.038). PHI achieved an AUC of 0.872 in normal weight patients and 0.745 in obese patients, which outperformed the other predictors regardless of BMI category. In conclusion, PHI achieved the best predictive performance for detecting PCa and was not influenced by BMI. PMID:26754552

  4. A hybrid enrichment process combining conjugated polymer extraction and silica gel adsorption for high purity semiconducting single-walled carbon nanotubes (SWCNT)

    NASA Astrophysics Data System (ADS)

    Ding, Jianfu; Li, Zhao; Lefebvre, Jacques; Cheng, Fuyong; Dunford, Jeffrey L.; Malenfant, Patrick R. L.; Humes, Jefford; Kroeger, Jens

    2015-09-01

    A novel purification process for the enrichment of sc-SWCNTs that combines selective conjugated polymer extraction (CPE) with selective adsorption using silica gel, termed hybrid-CPE (h-CPE), has been developed, providing a high purity sc-SWCNT material with a significant improvement in process efficiency and yield. Using the h-CPE protocol, a greater than 5 fold improvement in yield can be obtained compared to traditional CPE while obtaining sc-SWCNT with a purity >99.9% as assessed by absorption spectroscopy and Raman mapping. Thin film transistor devices using the h-CPE derived sc-SWCNTs as the semiconductor possess mobility values ranging from 10-30 cm2 V-1 s-1 and current ON/OFF ratio of 104-105 for channel lengths between 2.5 and 20 μm.A novel purification process for the enrichment of sc-SWCNTs that combines selective conjugated polymer extraction (CPE) with selective adsorption using silica gel, termed hybrid-CPE (h-CPE), has been developed, providing a high purity sc-SWCNT material with a significant improvement in process efficiency and yield. Using the h-CPE protocol, a greater than 5 fold improvement in yield can be obtained compared to traditional CPE while obtaining sc-SWCNT with a purity >99.9% as assessed by absorption spectroscopy and Raman mapping. Thin film transistor devices using the h-CPE derived sc-SWCNTs as the semiconductor possess mobility values ranging from 10-30 cm2 V-1 s-1 and current ON/OFF ratio of 104-105 for channel lengths between 2.5 and 20 μm. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04851f

  5. Rapid and efficient treatment of wastewater with high-concentration heavy metals using a new type of hydrogel-based adsorption process.

    PubMed

    Zhou, Guiyin; Liu, Chengbin; Chu, Lin; Tang, Yanhong; Luo, Shenglian

    2016-11-01

    In this study, a new type of double-network hydrogel sorbent was developed to remove heavy metals in wastewater. The amino-functionalized Starch/PAA hydrogel (NH2-Starch/PAA) could be conducted in a wide pH and the adsorption process could rapidly achieve the equilibrium. The adsorption capacity got to 256.4mg/g for Cd(II). Resultantly, even though Cd(II) concentration was as high as 180mg/L, the Cd(II) could be entirely removed using 1g/L sorbent. Furthermore, the desirable mechanical durability of the adsorbent allowed easy separation and reusability. In the fixed-bed column experiments, the treatment volume of the effluent with a high Cd(II) concentration of 200mg/L reached 2400BV (27.1L) after eight times cycle. The NH2-Starch/PAA overcame the deficiency of conventional sorbents that could not effectively treat the wastewater with relatively high metal concentrations. This work provides a new insight into omnidirectional enhancement of sorbents for removing high-concentration heavy metals in wastewater.

  6. Galectin-3: a possible complementary marker to the PSA blood test

    PubMed Central

    Nangia-Makker, Pratima; Kho, Dhonghyo; Bajaj, Madhuri; Smith, Daryn; Heilbrun, Lance; Raz, Avraham; Heath, Elisabeth

    2013-01-01

    The prostate-specific antigen (PSA) test has served as a blood marker of prostate cancer (PCa), and for monitoring recurrence/metastasis in patients after therapeutic intervention. However, the applicability/reliability of the PSA test was recently questioned as it is not without challenges, in particular in men who have PCa without an elevated PSA (false negative), or in men who are disease-free with elevated levels of PSA (false positive). Galectin-3 is a tumor-associated protein; present in the seminal fluid and is a substrate for the PSA enzyme e.g., a chymotrypsin-like serine protease. We hypothesized that the cleavage status and level of galectin-3 in the prostate tissue and sera are associated with PCa. Thus, we compared galectin-3 levels obtained from sera of non-cancer urology patients to those of metastatic PCa patients. The data were confirmed by analyzing PCa tissue arrays. Here, we report that galectin-3 levels in the sera of patients with metastatic PCa were uniformly higher as compared to the non-cancer patient controls. The data suggest that galectin-3 serum level may be a useful serum complementary marker to the PSA blood test to be used for initial and follow-up PSA complimentary diagnostic/prognostic tool for recurrence in PCa patients. PMID:23625538

  7. Distinctive PSA-NCAM and NCAM hallmarks in glutamate-induced dendritic atrophy and synaptic disassembly.

    PubMed

    Podestá, María Fernanda; Yam, Patricia; Codagnone, Martín Gabriel; Uccelli, Nonthué Alejandra; Colman, David; Reinés, Analía

    2014-01-01

    Dendritic and synapse remodeling are forms of structural plasticity that play a critical role in normal hippocampal function. Neural cell adhesion molecule (NCAM) and its polysialylated form (PSA-NCAM) participate in neurite outgrowth and synapse formation and plasticity. However, it remains unclear whether they contribute to dendritic retraction and synaptic disassembly. Cultured hippocampal neurons exposed to glutamate (5 µM) showed a reduced MAP-2 (+) area in the absence of neuronal death 24 h after the insult. Concomitantly, synapse loss, revealed by decreased synaptophysin and post-synaptic density-95 cluster number and area, together with changes in NCAM and PSA-NCAM levels were found. Dendritic atrophy and PSA-NCAM reduction proved NMDA-receptor dependent. Live-imaging experiments evidenced dendritic atrophy 4 h after the insult; this effect was preceded by smaller NCAM clusters (1 h) and decreased surface and total PSA-NCAM levels (3 h). Simultaneously, total NCAM cluster number and area remained unchanged. The subsequent synapse disassembly (6 h) was accompanied by reductions in total NCAM cluster number and area. A PSA mimetic peptide prevented both the dendritic atrophy and the subsequent synaptic changes (6 h) but had no effect on the earliest synaptic remodeling (3 h). Thus, NCAM-synaptic reorganization and PSA-NCAM level decrease precede glutamate-induced dendritic atrophy, whereas the NCAM level reduction is a delayed event related to synapse loss. Consequently, distinctive stages in PSA-NCAM/NCAM balance seem to accompany glutamate-induced dendritic atrophy and synapse loss.

  8. Surfactant adsorption kinetics in microfluidics

    PubMed Central

    Riechers, Birte; Maes, Florine; Akoury, Elias; Semin, Benoît; Gruner, Philipp; Baret, Jean-Christophe

    2016-01-01

    Emulsions are metastable dispersions. Their lifetimes are directly related to the dynamics of surfactants. We design a microfluidic method to measure the kinetics of adsorption of surfactants to the droplet interface, a key process involved in foaming, emulsification, and droplet coarsening. The method is based on the pH decay in the droplet as a direct measurement of the adsorption of a carboxylic acid surfactant to the interface. From the kinetic measurement of the bulk equilibration of the pH, we fully determine the adsorption process of the surfactant. The small droplet size and the convection during the droplet flow ensure that the transport of surfactant through the bulk is not limiting the kinetics of adsorption. To validate our measurements, we show that the adsorption process determines the timescale required to stabilize droplets against coalescence, and we show that the interface should be covered at more than 90% to prevent coalescence. We therefore quantitatively link the process of adsorption/desorption, the stabilization of emulsions, and the kinetics of solute partitioning—here through ion exchange—unraveling the timescales governing these processes. Our method can be further generalized to other surfactants, including nonionic surfactants, by making use of fluorophore–surfactant interactions. PMID:27688765

  9. Surfactant adsorption kinetics in microfluidics

    NASA Astrophysics Data System (ADS)

    Riechers, Birte; Maes, Florine; Akoury, Elias; Semin, Benoît; Gruner, Philipp; Baret, Jean-Christophe

    2016-10-01

    Emulsions are metastable dispersions. Their lifetimes are directly related to the dynamics of surfactants. We design a microfluidic method to measure the kinetics of adsorption of surfactants to the droplet interface, a key process involved in foaming, emulsification, and droplet coarsening. The method is based on the pH decay in the droplet as a direct measurement of the adsorption of a carboxylic acid surfactant to the interface. From the kinetic measurement of the bulk equilibration of the pH, we fully determine the adsorption process of the surfactant. The small droplet size and the convection during the droplet flow ensure that the transport of surfactant through the bulk is not limiting the kinetics of adsorption. To validate our measurements, we show that the adsorption process determines the timescale required to stabilize droplets against coalescence, and we show that the interface should be covered at more than 90% to prevent coalescence. We therefore quantitatively link the process of adsorption/desorption, the stabilization of emulsions, and the kinetics of solute partitioning—here through ion exchange—unraveling the timescales governing these processes. Our method can be further generalized to other surfactants, including nonionic surfactants, by making use of fluorophore-surfactant interactions.

  10. Real-life experience of using conventional disease-modifying anti-rheumatic drugs (DMARDs) in psoriatic arthritis (PsA). Retrospective analysis of the efficacy of methotrexate, sulfasalazine, and leflunomide in PsA in comparison to spondyloarthritides other than PsA and literature review of the use of conventional DMARDs in PsA

    PubMed Central

    Roussou, Euthalia; Bouraoui, Aicha

    2017-01-01

    Objective With the aim of assessing the response to treatment with conventional disease-modifying anti-rheumatic drugs (DMARDs) used in patients with psoriatic arthritis (PsA), data on methotrexate, sulfasalazine (SSZ), and leflunomide were analyzed from baseline and subsequent follow-up (FU) questionnaires completed by patients with either PsA or other spondyloarthritides (SpAs). Material and Methods A single-center real-life retrospective analysis was performed by obtaining clinical data via questionnaires administered before and after treatment. The indices used were erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Function Index (BASFI), wellbeing (WB), and treatment effect (TxE). The indices measured at baseline were compared with those measured on one occasion in a FU visit at least 1 year later. Results A total of 73 patients, 51 with PsA (mean age 49.8±12.8 years; male-to-female ratio [M:F]=18:33) and 22 with other SpAs (mean age 50.6±16 years; M:F=2:20), were studied. BASDAI, BASFI, and WB displayed consistent improvements during FU assessments in both PsA patients and controls in comparison to baseline values. SSZ exhibited better efficacy as confirmed by TxE in both PsA patients and controls. ESR and CRP displayed no differences in either the PsA or the SpA group between the cases before and after treatment. Conclusion Real-life retrospective analysis of three DMARDs used in PsA (and SpAs other than PsA) demonstrated that all three DMARDs that were used brought about improvements in BASDAI, BASFI, TxE, and WB. However, the greatest improvements at FU were seen with SSZ use in both PsA and control cohorts. PMID:28293446

  11. Practice Patterns of Korean Urologists for Screening and Managing Prostate Cancer according to PSA Level

    PubMed Central

    Chung, Mun Su; Lee, Seung Hwan; Lee, Dong Hoon; Kim, Se Joong; Kim, Choung Soo; Lee, Kyu Sung; Jung, Jae Il; Kim, Sae Woong; Lee, Yil Seob

    2012-01-01

    Purpose There are still debates on the benefit of mass screening for prostate cancer (PCA) by prostate specific antigen (PSA) testing, and on systemized surveillance protocols according to PSA level. Furthermore, there is a paucity of literature on current practice patterns according to PSA level in the Korean urologic field. Here, we report the results of a nationwide, multicenter, retrospective chart-review study. Materials and Methods Overall 2122 Korean men (>40 years old, PSA >2.5 ng/mL) were included in our study (from 122 centers, in 2008). The primary endpoint was to analyze the rate of prostate biopsy according to PSA level. Secondary aims were to analyze the detection rate of PCA, the clinical features of patients, and the status of surveillance for PCA according to PSA level. Results The rate of prostate biopsy was 7.1%, 26.3%, 54.2%, and 64.3% according to PSA levels of 2.5-3.0, 3.0-4.0, 4.0-10.0, and >10.0 ng/mL, respectively, and the PCA detection rate was 16.0%, 22.2%, 20.2%, and 59.6%, respectively. At a PSA level >4.0 ng/mL, we found a lower incidence of prostate biopsy in local clinics than in general hospitals (21.6% vs. 66.2%, respectively). A significant proportion (16.6%) of patients exhibited high Gleason scores (≥8) even in the group with low PSA values (2.5-4.0 ng/mL). Conclusion We believe that the results from this nationwide study might provide an important database for the establishment of practical guidelines for the screening and management of PCA in Korean populations. PMID:23074113

  12. Predicting Post-External Beam Radiation Therapy PSA Relapse of Prostate Cancer Using Pretreatment MRI

    SciTech Connect

    Fuchsjaeger, Michael H.; Pucar, Darko; Zelefsky, Michael J.; Zhang Zhigang; Mo Qianxing; Ben-Porat, Leah S.; Shukla-Dave, Amita; Wang Liang; Reuter, Victor E.; Hricak, Hedvig

    2010-11-01

    Purpose: To investigate whether pretreatment endorectal magnetic resonance imaging (MRI) findings can predict biochemical relapse in patients with clinically localized prostate cancer treated with external beam radiation therapy (EBRT). Methods and Materials: Between January 2000 and January 2002, 224 patients (median age, 69 years; age range, 45-82 years) with biopsy-proven prostate cancer underwent endorectal MRI before high-dose ({>=}81Gy) EBRT. The value of multiple clinical and MRI variables in predicting prostate-specific antigen (PSA) relapse at 5 years was determined by use of univariate and multivariate stepwise Cox regression. Clinical variables included pretreatment PSA, clinical T stage, Gleason score, use of neoadjuvant hormonal therapy, and radiation dose. Magnetic resonance imaging variables, derived from retrospective consensus readings by two radiologists, were used to measure intraprostatic and extraprostatic tumor burden. Results: After a median follow-up of 67 months, PSA relapse developed in 37 patients (16.5%). The significant predictors of PSA relapse on univariate analysis were pretreatment PSA, clinical T stage, and multiple MRI variables, including MRI TN stage score; extracapsular extension (ECE) status; number of sextants involved by ECE, all lesions, or index (dominant) lesion; apical involvement; and diameter and volume of index lesion. Pretreatment PSA and ECE status were the only significant independent predictors on multivariate analysis (p < 0.05 for both). Extracapsular extension status was associated with the highest hazard ratio, 3.04; 5-year PSA relapse rates were 7% for no ECE, 20% for unilateral ECE, and 48% for bilateral ECE. Conclusions: Magnetic resonance imaging findings can be used to predict post-EBRT PSA relapse, with ECE status on MRI and pretreatment PSA being significant independent predictors of this endpoint.

  13. Process development for the batch and bulk removal and recovery of a hazardous, water-soluble azo dye (Metanil Yellow) by adsorption over waste materials (Bottom Ash and De-Oiled Soya).

    PubMed

    Mittal, Alok; Gupta, V K; Malviya, Arti; Mittal, Jyoti

    2008-03-01

    Bottom Ash and De-Oiled Soya have been used as adsorbents for the removal of a hazardous azo dye-Metanil Yellow from its aqueous solutions. Adsorption of Metanil Yellow on these adsorbents has been studied as function of time, temperature, concentration and pH. Batch adsorption studies, kinetic studies and column operations enabled extraction of lethal dye from wastewaters. Adsorption equilibrium data confirms both Langmuir and Freundlich isotherm models and monolayer coverage of dye over adsorbents. Kinetic data have been employed to calculate specific rate constants, indicating thereby involvement of first order kinetics in the on-going adsorption and activation energy was determined as 0.813 and 1.060 kJ mol(-1) for Bottom Ash and De-Oiled Soya, respectively. For both adsorbents, the adsorption process has been found governing by film diffusion, over the entire concentration range. Column operations have also been performed for the bulk removal of the dye and also to examine the practical utilization of fixed bed adsorption technique in elimination of dangerous effluent. Saturation factors for Bottom Ash and De-Oiled Soya columns have been calculated as 99.15 and 99.38%, respectively. Attempts have also been made to regenerate the dye from the exhausted columns using aqueous sodium hydroxide as eluent.

  14. Random sequential adsorption on fractals.

    PubMed

    Ciesla, Michal; Barbasz, Jakub

    2012-07-28

    Irreversible adsorption of spheres on flat collectors having dimension d < 2 is studied. Molecules are adsorbed on Sierpinski's triangle and carpet-like fractals (1 < d < 2), and on general Cantor set (d < 1). Adsorption process is modeled numerically using random sequential adsorption (RSA) algorithm. The paper concentrates on measurement of fundamental properties of coverages, i.e., maximal random coverage ratio and density autocorrelation function, as well as RSA kinetics. Obtained results allow to improve phenomenological relation between maximal random coverage ratio and collector dimension. Moreover, simulations show that, in general, most of known dimensional properties of adsorbed monolayers are valid for non-integer dimensions.

  15. Incorporating Known Genetic Variants Does Not Improve the Accuracy of PSA Testing to Identify High Risk Prostate Cancer on Biopsy

    PubMed Central

    Gilbert, Rebecca; Martin, Richard M.; Evans, David M.; Tilling, Kate; Davey Smith, George; Kemp, John P.; Lane, J. Athene; Hamdy, Freddie C.; Neal, David E.; Donovan, Jenny L.; Metcalfe, Chris

    2015-01-01

    Introduction Prostate-specific antigen (PSA) testing is a widely accepted screening method for prostate cancer, but with low specificity at thresholds giving good sensitivity. Previous research identified four single nucleotide polymorphisms (SNPs) principally associated with circulating PSA levels rather than with prostate cancer risk (TERT rs2736098, FGFR2 rs10788160, TBX3 rs11067228, KLK3 rs17632542). Removing the genetic contribution to PSA levels may improve the ability of the remaining biologically-determined variation in PSA to discriminate between high and low risk of progression within men with identified prostate cancer. We investigate whether incorporating information on the PSA-SNPs improves the discrimination achieved by a single PSA threshold in men with raised PSA levels. Materials and Methods Men with PSA between 3-10ng/mL and histologically-confirmed prostate cancer were categorised as high or low risk of progression (Low risk: Gleason score≤6 and stage T1-T2a; High risk: Gleason score 7–10 or stage T2C). We used the combined genetic effect of the four PSA-SNPs to calculate a genetically corrected PSA risk score. We calculated the Area under the Curve (AUC) to determine how well genetically corrected PSA risk scores distinguished men at high risk of progression from low risk men. Results The analysis includes 868 men with prostate cancer (Low risk: 684 (78.8%); High risk: 184 (21.2%)). Receiver operating characteristic (ROC) curves indicate that including the 4 PSA-SNPs does not improve the performance of measured PSA as a screening tool for high/low risk prostate cancer (measured PSA level AU C = 59.5% (95% CI: 54.7,64.2) vs additionally including information from the 4 PSA-SNPs AUC = 59.8% (95% CI: 55.2,64.5) (p-value = 0.40)). Conclusion We demonstrate that genetically correcting PSA for the combined genetic effect of four PSA-SNPs, did not improve discrimination between high and low risk prostate cancer in men with raised PSA levels (3-10ng

  16. Ion Exchange and Adsorption of Inorganic Contaminants

    EPA Science Inventory

    In the first part of the chapter, the fundamentals of ion exchange and adsorption processes are explained, with the goal of demonstrating how these principles influence process design for inorganic contaminant removal. In the second part, ion exchange and adsorption processes th...

  17. Immunoassay for the discrimination of free prostate-specific antigen (fPSA) forms with internal cleavages at Lys145 or Lys146 from fPSA without internal cleavages at Lys145 or Lys146

    PubMed Central

    Peltola, Mari T.; Niemelä, Pauliina; Alanen, Kalle; Nurmi, Martti; Lilja, Hans; Pettersson, Kim

    2014-01-01

    Total levels of circulating prostate-specific antigen (tPSA) are strongly associated with prostate cancer (PCa) risk and outcome but benign prostate disease is the most frequent cause of a moderately elevated PSA level. Free PSA (fPSA) forms are independently associated with PCa risk and contribute modest diagnostic enhancements above and beyond tPSA alone. We developed an immunoassay for fPSA subfractions containing internal cleavages at Lys145 or Lys146 (fPSA-N). The assay was based on blocking intact single-chain fPSA (fPSA-I) with antibody 4D4 which does not detect PSA containing internal cleavages at Lys145 or Lys146. We also measured fPSA-N in blood from healthy volunteers and in anti-coagulated plasma from 76 men with or without evidence of PCa at biopsy. The analytical and functional detection limits of this assay were 0.016 ng/mL and 0.10 ng/mL, respectively. The median recovery of male fPSA-N from female plasma was 95.0 %. All 12 female samples (average age 28 years) had fPSA-N concentrations at or below the analytical detection limit. The median fPSA-N concentration (0.050 ng/mL) in 9 healthy male volunteers (age < 40 years) was below the functional detection limit, 0.420 ng/mL in 27 patients with benign prostate conditions and 0.239 ng/mL in 49 patients with PCa. Deming regression analysis of the patient samples showed that the measured fPSA-N concentrations were generally 23% lower than the previously calculated (fPSA minus fPSA-I) concentrations, likely due to differences in the antibody combinations used. In conclusion, we have developed a sensitive, specific and direct immunoassay for fPSA-N which can be used to study the clinical relevance of this PSA isoform. PMID:21554885

  18. Simultaneous removing of Pb(2+) ions and alizarin red S dye after their complexation by ultrasonic waves coupled adsorption process: Spectrophotometry detection and optimization study.

    PubMed

    Pourebrahim, F; Ghaedi, M; Dashtian, K; Heidari, F; Kheirandish, S

    2017-03-01

    Funthenalized chitosan (CS) was composited with mesoprous SBA-15 and characterized via. different techniques such as FT-IR and FE-SEM. Subsequently, this new material was applied for simulations ultrasound-assisted adsorption of Pb(2+) ion and alizarin red S (ARS) dye after their complexation. Efficient conventional variables in adsorption process such as initial ARS and Pb(2+) concentration, adsorbent mass and sonication time were studied by small central composite design (CCD) and optimized with desirability function approach. Lack of fit testes and model summary statistics for linear, 2FI, quadratic and cubic models were investigated and according to the insignificant lack of fit and maximizing the R-squared (R(2)), adjusted R-squared and the predicted R-squared quadratic model was selected for other step analysis for removal of ARS dye, while, for Pb(2+) ions 2FI model was selected as best model. Quadratic model ANOVA for ARS dye removal shows the F-value parameter (683.91), very low p-value model (<0.0001) and p-value lack of fit (0.0568) that implied this model was highly significant. Also, 2FI model ANOVA for Pb(2+) ions removal shows the F-value parameter (282.51), very low p-value model (<0.0001) and p-value lack of fit (2.05). According to desirability function approach maximum removal percentage of ARS (87.61%) and Pb(2+) ions (83.54%) was shown at optimum of condition that were set as at: 25 and 25mgL(-1), 0.028g and 11.8min for initial ARS and Pb(2+) ions concentration, adsorbent mass and sonication time, respectively. Finally, it was found that the equilibrium and kinetic of adsorption process follow the Langmuir isotherm and pseudo-second-order kinetic model, respectively. From the Langmuir isotherm, maximum monolayer capacity (qmax) was obtained 50.25 and 57.14mgg(-1) for ARS and Pb(2+) ions removal, respectively.

  19. Up-cycling waste glass to minimal water adsorption/absorption lightweight aggregate by rapid low temperature sintering: optimization by dual process-mixture response surface methodology.

    PubMed

    Velis, Costas A; Franco-Salinas, Claudia; O'Sullivan, Catherine; Najorka, Jens; Boccaccini, Aldo R; Cheeseman, Christopher R

    2014-07-01

    Mixed color waste glass extracted from municipal solid waste is either not recycled, in which case it is an environmental and financial liability, or it is used in relatively low value applications such as normal weight aggregate. Here, we report on converting it into a novel glass-ceramic lightweight aggregate (LWA), potentially suitable for high added value applications in structural concrete (upcycling). The artificial LWA particles were formed by rapidly sintering (<10 min) waste glass powder with clay mixes using sodium silicate as binder and borate salt as flux. Composition and processing were optimized using response surface methodology (RSM) modeling, and specifically (i) a combined process-mixture dual RSM, and (ii) multiobjective optimization functions. The optimization considered raw materials and energy costs. Mineralogical and physical transformations occur during sintering and a cellular vesicular glass-ceramic composite microstructure is formed, with strong correlations existing between bloating/shrinkage during sintering, density and water adsorption/absorption. The diametrical expansion could be effectively modeled via the RSM and controlled to meet a wide range of specifications; here we optimized for LWA structural concrete. The optimally designed LWA is sintered in comparatively low temperatures (825-835 °C), thus potentially saving costs and lowering emissions; it had exceptionally low water adsorption/absorption (6.1-7.2% w/wd; optimization target: 1.5-7.5% w/wd); while remaining substantially lightweight (density: 1.24-1.28 g.cm(-3); target: 0.9-1.3 g.cm(-3)). This is a considerable advancement for designing effective environmentally friendly lightweight concrete constructions, and boosting resource efficiency of waste glass flows.

  20. Fabrication of composite polymer foam films at the liquid/liquid interface through emulsion-directed assembly and adsorption processes.

    PubMed

    Geng, Yuanyuan; Liu, Mei; Tong, Kun; Xu, Jian; Lee, Yong-Ill; Hao, Jingcheng; Liu, Hong-Guo

    2014-03-04

    The foam films of polystyrene-b-poly(acrylic acid)-b-polystyrene (PS-b-PAA-b-PS) doped with Cd(II) or Pb(II) species were fabricated at the planar liquid/liquid interfaces between a DMF/chloroform (v/v: 1/1) solution of the polymer and aqueous solutions containing cadmium acetate or lead acetate at ambient temperature. Optical microscopic observation shows the thin film is uniform on a larger length scale. Transmission electron microscopic (TEM) investigations reveal that the foam films are made up of microcapsules with the size of several hundreds of nanometers to micrometers. The walls of the microcapsules have a layered structure decorating with nanofibers and hollow nanospheres, where numerous inorganic fine nanoparticles are dispersed homogeneously. The film formation is a result of emulsion droplet-templated assembly and adsorption of the formed microcapsules at the planar liquid/liquid interface. Because of the miscibility of DMF with chloroform and water, DMF migrates to the aqueous phase while water migrates to the organic phase across the interface, resulting in the formation of a W/O emulsion, as revealed by optical microscopic observation, freeze fracture transmission electron microscopic (FF-TEM) observation, and dynamic laser scattering (DLS) investigation. The triblock copolymer molecules and the inorganic species adsorb and self-assemble around the emulsion drops, leading to the formation of the composite microcapsules. X-ray photoelectron spectroscopic (XPS) and FTIR spectroscopic results indicate that two kinds of Cd(II) or Pb(II) species, metal oxide or hydroxide, resulting from the hydrolysis of the metal ions and the coordinated metal ions to the carboxyl groups coexist in the formed thin films, which transform to metal sulfide completely after treating with hydrogen sulfide to get metal sulfide nanoparticle-doped polymer thin films.

  1. A model for trace metal sorption processes at the calcite surface: Adsorption of Cd2+ and subsequent solid solution formation

    USGS Publications Warehouse

    Davis, J.A.; Fuller, C.C.; Cook, A.D.

    1987-01-01

    The rate of Cd2+ sorption by calcite was determined as a function of pH and Mg2+ in aqueous solutions saturated with respect to calcite but undersaturated with respect to CdCO3. The sorption is characterized by two reaction steps, with the first reaching completion within 24 hours. The second step proceeded at a slow and nearly constant rate for at least 7 days. The rate of calcite recrystallization was also studied, using a Ca2+ isotopic exchange technique. Both the recrystallization rate of calcite and the rate of slow Cd2+ sorption decrease with increasing pH or with increasing Mg2+. The recrystallization rate could be predicted from the number of moles of Ca present in the hydrated surface layer. A model is presented which is consistent with the rates of Cd2+ sorption and Ca2+ isotopic exchange. In the model, the first step in Cd2+ sorption involves a fast adsorption reaction that is followed by diffusion of Cd2+ into a surface layer of hydrated CaCO3 that overlies crystalline calcite. Desorption of Cd2+ from the hydrated layer is slow. The second step is solid solution formation in new crystalline material, which grows from the disordered mixture of Cd and Ca carbonate in the hydrated surface layer. Calculated distribution coefficients for solid solutions formed at the surface are slightly greater than the ratio of equilibrium constants for dissolution of calcite and CdCO3, which is the value that would be expected for an ideal solid solution in equilibrium with the aqueous solution. ?? 1987.

  2. SEPARATIONS RESEARCH AT THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY - TOWARDS RECOVERY OF VOCS AND METALS USING MEMBRANES AND ADSORPTION PROCESSES

    EPA Science Inventory

    The USEPA's National Risk Management Research Laboratory is investigating new separations materials and processes for removal and recovery of volatile organic compounds (VOCs) and toxic metals from wastestreams and industrial process streams. Research applying membrane-based perv...

  3. Potentiometric stripping analysis (PSA) for monitoring of antimony in samples of vegetation from a mining area.

    PubMed

    Toro Gordillo, M C; Pinilla Gil, E; Rodríguez González, M A; Murciego Murciego, A; Ostapczuk, P

    2001-06-01

    A potentiometric stripping analysis (PSA) method has been developed and checked for the fast and reliable determination of antimony in vegetation samples of Cistus ladanifer from a mining area in Badajoz, Southwest Spain. The method, modified from previous PSA methods for Sb in environmental samples, is based on dry ashing of the homogenized leaves, dissolution in hydrochloric acid, and PSA analysis on a mercury film plated on to a glassy carbon disk electrode. The influence of experimental variables such as the deposition potential, the deposition time, the signal stability and the calibration parameters, has been investigated. The method has been compared with an independent technique (instrumental neutron activation analysis) by analysis of standards and reference materials and comparison of the results. As a result of automation of the PSA equipment, the proposed method enables unattended analysis of 20 digested samples in a total time of 2 h, thus providing a useful tool for Sb monitoring of a large number of samples.

  4. COS Imaging TA and Spectroscopic WCA-PSA/BOA offset verifications

    NASA Astrophysics Data System (ADS)

    Penton, Steven

    2013-10-01

    This program builds upon the monitoring and calibration of the FGSs (13616 - HST Cycle 21 Focal Plane Calibration (SI-FGS Alignment)). HST 13616 performs back-to-back PSA/MIRRORA & PSA/MIRRORB ACQ/IMAGES, from which all the results herein are bootstrapped.The list of proposals, cycles, and the order in which the alignment is checked is given below. 11878->12399->12781->13171->13616 C17->C18 ->C19->C20->C21 STIS->WFC3->ACS->COSThis program will be repeated every cycle and we will once again use it's COS exposures as the baseline for this program.This program performs a PSA/MIRRORA ACQ/IMAGE on a target that should already be centered in the aperture. This verifies the COS NUV PSA aperture position in the SIAF. After this PSA+MIRRORA ACQ/IMAGE, a PSA+MIRRORB ACQ/IMAGE is then performed. This exposure bootstraps the PSA+MIRRORB centering to the PSA+MIRROR SIAF verification. This allows us to monitor the properties of the PSA+MIRRORB image in a controlled way on a centered target. No spectra are taken in 13616 due to time constraints.This program extends the SIAF verification of 13616 to the other two ACQ/IMAGE combinations (BOA+MIRRORA & BOA+MIRRORB) by bootstraping from the PSA+MIRRORB verification of 13616.Visit 1 of this program begins with a PSA+MIRRORB NUV ACQ/IMAGE followed by a BOA+MIRRORA ACQ/IMAGE. Both observations are high S/N to get the most accurate centering information possible. The program then takes a PSA+MIRRORB IMAGE to ensure that we are still properly centered. We prefer that Visit 01 of this program executes within 45 days of Visit 02 of 13616, to ensure that no long term instrument or telescope focus changes impart our results.After the Imaging verification , Visit 1 of this program will obtain a S/N > 60 NUV spectrum using the most popular NUV grating (G230L, G185M, & G285M), and FUV Spectra using G130M/1309 and G140L/1280. This allows the direct verification of the NUV and FUV WCA-to-PSA cross-dispersion offsets used by ACQ/PEAKXD.Visit 02 of

  5. [Parameters of PSA fractions in early diagnosis of prostatic cancer in healthy males over 50].

    PubMed

    Loran, O B; Krokhotina, L V; Pushkar', D Iu; Valiev, A Z; Rasner, P I

    1999-01-01

    292 symptomless males aged 50-85 years were examined for blood prostate-specific antigen (PSA) for early diagnosis of prostatic cancer. Males with total PSA (TPSA) higher than age-specific standard underwent free PSA (FPSA) assay to estimate FPSA/TPSA and transperineal biopsy of the prostate. TPSA ranged from 0.3 to 112.0 ng/ml and exceeded the age standard in 102 examinees (35%). Prognostically unfavorable FPSA/TPSA (under 15%) was registered in 17(5.8%) examinees. Biopsy of the prostate has revealed cancer in 7 of them. Among those whose TPSA was above the standard, but FPSA/TPSA > 15%, morphologically verified prostatic cancer was detected in 5 males. It is thought valid to include the method of PSA fractions estimation in the program of screening for males at risk to develop prostatic cancer as it is simple, cost effective and highly informative.

  6. Serum prostate-specific antigen (PSA) concentration is positively associated with rate of disease reclassification on subsequent active surveillance prostate biopsy in men with low PSA density

    PubMed Central

    Umbehr, Martin H.; Platz, Elizabeth A.; Peskoe, Sarah B.; Bhavsar, Nrupen A.; Epstein, Jonathan I.; Landis, Patricia; Partin, Alan W.; Carter, H. Ballentine

    2014-01-01

    Objective To investigate the association between serum prostate-specific antigen (PSA) concentration at active surveillance (AS) entry and disease reclassification on subsequent AS biopsy (‘biopsy reclassification’) in men with low PSA density (PSAD). To investigate whether a clinically meaningful PSA threshold for AS eligibility/ineligibility for men with low PSAD can be identified based on risk of subsequent biopsy reclassification. Patients and Methods We included men enrolled in the Johns Hopkins AS Study (JHAS) who had a PSAD of <0.15 ng/mL/g (640 men). We estimated the incidence rates (IRs; per 100 person years) and hazard ratios (HR) of biopsy reclassification (Gleason score ≥ 7, any Gleason pattern 4 or 5, ≥3 positive cores, or ≥50% cancer involvement/biopsy core) for categories of serum PSA concentration at the time of entry into AS. We generated predicted IRs using Poisson regression to adjust for age and prostate volume, mean percentage free PSA (ratio of free to total PSA) and maximum percentage biopsy core involvement with cancer. Results The unadjusted IRs (per 100 person years) of biopsy reclassification across serum PSA concentration at entry into JHAS showed, in general, an increase; however, the pattern was not linear with higher IRs in the group ≥ 4 to <6 ng/mL (14.2, 95% confidence interval [CI] 11.8–17.2%) when compared with ≥ 6 to <8 ng/mL (8.4, 95% CI 5.7–12.3%) but almost similar IRs when compared with the group ≥ 8 to <10 ng/mL (14.8, 95% CI 8.4–26.1%). The adjusted predicted IRs of reclassification showed a similar non-linear increase in IRs, whereby the rates around 4 ng/mL were similar to the rates around 10 ng/mL. Conclusion Risk for biopsy reclassification increased non-linearly across PSA concentration in men with low PSAD, whereby no obvious clinically meaningful threshold could be identified. This information could be incorporated into decision-making for AS. However, longer follow-up times are needed to

  7. Process development for removal and recovery of cadmium from wastewater by a low-cost adsorbent: Adsorption rates and equilibrium studies

    SciTech Connect

    Periasamy, K.; Namasivayam, C. . Dept. of Environmental Sciences)

    1994-02-01

    Activated carbon prepared from peanut hulls (PHC), an agricultural waste by-product, has been used for the adsorption of Cd(II) from synthetic wastewater. The adsorption data fit better with the Freundlich adsorption isotherm. The applicability of the Lagergren kinetic model has also been investigated. An almost quantitative removal of 20 mg/L Cd(II) by 0.7 g of PHC/L of aqueous solution was observed in the pH range 3.5--9.5. A comparative study with a commercial granular activated carbon (CAC) showed that the adsorption capacity (K[sub f]) of PHC was 31 times larger than that of CAC.

  8. A Comparison of the Biological Features of Prostate Cancer with (PSA+, PSMA+) Profile according to RKIP

    PubMed Central

    Ben Jemaa, Awatef; Bouraoui, Yosra; Sallami, Sataa; Nouira, Yassine; Oueslati, Ridha

    2013-01-01

    Purpose. To investigate differences in the biological features of the most immunoexpressed prostate cancer (PC) profiles (PSA+, PSMA+) according to the RKIP. Methods. 19 PC with dominant Gleason grade ≥8 were studied. Expression of PSA, PSMA, RKIP, Raf-1, MEK-1, ERK-1, ERK-2, p-Akt (T308), p-Akt (S473), NF-κB p50, and NF-κBp65 were detected immunohistochemically. Results. Loss of RKIP in the most immunoexpressed PC (PSA+, PSMA+) profile was associated with increased levels of PSA and PSMA expression. Intensities of immunoreactions to PSA and PSMA were higher in cancer cells negative for RKIP (12.51 ± 1.6 and 34.95 ± 1.92) compared to those positive for RKIP (4.68 ± 1.11 and 28.56 ± 0.91). In parallel, missing RKIP expression in PC patients with PSA+, PSMA+ profile was connected with increased components of both Raf-1/MEK/ERK and NF-κB (p65/p50), whereas Akt is activated independently of RKIP. Conclusions. Although characterized by the same (PSA+, PSMA+) profile, PC phenotype missing the RKIP related to invasive potential and greater biological aggressiveness reflected in overexpression of components of Raf-1/MEK/ERK and NF-κB (p65/p50) in which Akt is activated independently of RKIP. Taking into account the PC phenotypes according to RKIP among PSA-PSMA profiles may improve distinguishing them from cancers that will become more aggressive and therefore adapt the therapeutic strategies in those patients. PMID:23991415

  9. Improvement of Prostate Cancer Diagnosis by Detecting PSA Glycosylation-Specific Changes

    PubMed Central

    Llop, Esther; Ferrer-Batallé, Montserrat; Barrabés, Sílvia; Guerrero, Pedro Enrique; Ramírez, Manel; Saldova, Radka; Rudd, Pauline M.; Aleixandre, Rosa N.; Comet, Josep; de Llorens, Rafael; Peracaula, Rosa

    2016-01-01

    New markers based on PSA isoforms have recently been developed to improve prostate cancer (PCa) diagnosis. However, novel approaches are still required to differentiate aggressive from non-aggressive PCa to improve decision making for patients. PSA glycoforms have been shown to be differentially expressed in PCa. In particular, changes in the extent of core fucosylation and sialylation of PSA N-glycans in PCa patients compared to healthy controls or BPH patients have been reported. The objective of this study was to determine these specific glycan structures in serum PSA to analyze their potential value as markers for discriminating between BPH and PCa of different aggressiveness. In the present work, we have established two methodologies to analyze the core fucosylation and the sialic acid linkage of PSA N-glycans in serum samples from BPH (29) and PCa (44) patients with different degrees of aggressiveness. We detected a significant decrease in the core fucose and an increase in the α2,3-sialic acid percentage of PSA in high-risk PCa that differentiated BPH and low-risk PCa from high-risk PCa patients. In particular, a cut-off value of 0.86 of the PSA core fucose ratio, could distinguish high-risk PCa patients from BPH with 90% sensitivity and 95% specificity, with an AUC of 0.94. In the case of the α2,3-sialic acid percentage of PSA, the cut-off value of 30% discriminated between high-risk PCa and the group of BPH, low-, and intermediate-risk PCa with a sensitivity and specificity of 85.7% and 95.5%, respectively, with an AUC of 0.97. The latter marker exhibited high performance in differentiating between aggressive and non-aggressive PCa and has the potential for translational application in the clinic. PMID:27279911

  10. Motexafin lutetium-photodynamic therapy of prostate cancer: Short and long term effects on PSA

    PubMed Central

    Patel, Hiral; Mick, Rosemarie; Finlay, Jarod; Zhu, Timothy C.; Rickter, Elizabeth; Cengel, Keith A.; Malkowicz, S. Bruce; Hahn, Stephen M.; Busch, Theresa M.

    2009-01-01

    Purpose: The time course of serum PSA response to photodynamic therapy (PDT) of prostate cancer was measured. Experimental Design: Seventeen patients were treated in a Phase I trial of motexafin lutetium-PDT. PDT dose was calculated in each patient as the product of the ex vivo-measured pre-PDT photosensitizer level and the in situ-measured light dose. Serum PSA level was measured within two months prior to PDT (baseline), and at day 1; weeks 1-3; months 1, 2 and 3; months 4-6 and months 7-11 after PDT. Results: At 24h after PDT, serum PSA increased by 98±36% (mean ± SE) relative to baseline levels (p=0.007). When patients were dichotomized based on median PDT dose, those who received high PDT dose demonstrated a 119±52% increase in PSA compared to a 54±27% increase in patients treated at low PDT dose. Patients treated with high vs. low PDT dose demonstrated a median biochemical delay of 82 vs. 43 days (p=0.024), with biochemical delay defined as the length of time between PDT and a nonreversible increase in PSA to a value ≥baseline. Conclusions: Results show PDT to induce large, transient increases in serum PSA levels. Patients who experienced high PDT dose demonstrated greater short-term increase in PSA and a significantly more durable PSA response (biochemical delay). These data strongly promote the need for individualized delivery of PDT dose and assessment of treatment effect in PDT of prostate cancer. Information gained from such patient-specific measurements could facilitate the introduction of multiple PDT sessions in patients who would benefit. PMID:18676760

  11. A Diet, Physical Activity, and Meditation Intervention in Men With Rising Prostate-Specific Antigen (PSA)

    DTIC Science & Technology

    2005-05-01

    prostate cancer ( PrCA ), one in three patients will experience an elevation in serum prostate antigen (PSA) within 10 years. This rises to one in two...at 15 years. After such evidence of recurrence, the most common treatment is androgen ablation. We hypothesize that the host- PrCA balance in...asymptomatic men with biochemically recurrent PrCA , as reflected by the PSA rise, is favorably affected by an intensive, vegetable-based diet, plus physical

  12. A Diet, Physical Activity, and Meditation Intervention in Men With Rising Prostate-Specific Antigen (PSA)

    DTIC Science & Technology

    2007-05-01

    stage prostate cancer ( PrCA ), one in three patients will experience an elevation in serum prostate antigen (PSA) within 10 years. This rises to one in...two at 15 years. After such evidence of recurrence, the most common treatment is androgen ablation. We hypothesize that the host- PrCA balance in...asymptomatic men with biochemically recurrent PrCA , as reflected by the PSA rise, is favorably affected by an intensive, vegetable-based diet, plus

  13. PSA doubling time kinetics during prostate cancer biochemical relapse after external beam radiation therapy

    SciTech Connect

    Bates, Andrew Tom . E-mail: andrew.bates@doctors.org.uk; Pickles, Tom; Paltiel, Chuck

    2005-05-01

    Purpose: To investigate whether prostate-specific antigen PSA doubling time (PSADT) is constant in men with biochemical prostate cancer relapse after external beam radiotherapy (EBRT). Methods and Materials: A total of 513 men treated radically with EBRT, with or without androgen ablation (AA), between 1993 and 2000, developed biochemical relapse. The slope of the ln (PSA) vs. time graph is calculated for the first two values after PSA nadir (first slope), the last two recorded PSAs (last slope), and all values excluding the first and final PSA (mid slope). Differences in these slopes were compared statistically with subgroup analysis for AA and secondary intervention. Results: For men treated with EBRT and AA first slope was faster than either mid slope (p = 0.031) or last slope (p < 0.001). Men treated with EBRT alone had no change in PSADT over time unless they subsequently received secondary intervention. This group had a more rapid last slope compared with mid slope (p < 0.001). Conclusions: PSA initially rises more rapidly after AA cessation, probably because of testosterone recovery. A subgroup of patients, who received secondary intervention after treatment with radiotherapy alone, showed a change in PSADT, to a faster velocity. This greater than constant exponential PSA growth is presumably the catalyst for secondary intervention. Otherwise, PSADT did not change during prostate cancer biochemical relapse.

  14. Can the Free/Total PSA Ratio Predict the Gleason Score Before Prostate Biopsy?

    PubMed Central

    Ceylan, Cavit; Gazel, Eymen; Keleş, İbrahim; Doluoğlu, Ömer; Yığman, Metin

    2016-01-01

    Objectives To determine whether there is a correlation between high Gleason score and free/total (f/t) prostate specific antigen (PSA) in patients newly diagnosed with prostate carcinoma. Materials and Methods The study included 272 prostate biopsy patients whose total PSA value ranged from 4–10 ng/ml. The patients were divided into 2 groups according to the f/t PSA ratio: Group 1 ≤ 15% and Group 2 > 15%. Furthermore, the groups were also compared to each other in terms of mild (≤ 6), moderate (= 7), and high (≥ 8) Gleason score. Results Group 1 consisted of 135 (49.6%) patients and Group 2 consisted of 137 (50.4%) patients. While 27 (20%) patients had a high Gleason score in Group 1, only 10 (7.3%) patients had a high Gleason score in Group 2 (p = 0.008). Using Spearman's correlation test, we found that the f/t PSA ratios were observed to decrease significantly in all patients with increased Gleason scores (p = 0.002, r = −0.185). Conclusion According to our study, there is a relationship between higher Gleason score and decreased f/t PSA ratio. Therefore, f/t PSA can be an indicator for predicting the Gleason score. PMID:26989367

  15. High-sensitivity detection of PSA by time-resolved fluorometry with Europium chelate

    NASA Astrophysics Data System (ADS)

    Nahm, Kie B.; Jeong, Jin H.; Kim, Byoung C.; Kim, Jae H.; Kim, Young M.; Jeong, Dong S.; Oh, Sang W.; Choi, Eui Y.; Ko, Dong S.

    2006-01-01

    Prostate-specific antigen (PSA) is an androgen-dependent glycoprotein protease (M.W. 33 kDa) and a member of kallikrein super-family of serine protease, and has chymotrypsin-like enzymatic activity. It is synthesized by the prostate epithelial cells and found in the prostate gland and seminal plasma as a major protein. It is widely used as a clinical marker for diagnosis, screening, monitoring and prognosis of prostate cancer. In normal male adults, the concentration of PSA in the blood is below 4 ng/ml and this value increases in patients with the prostate cancer or the benign prostatic hyperplasia (BPH) due to its leakage into the circulatory system. As such, systematic monitoring of the PSA level in the blood can provide critical information about the progress of the prostatic disease. We have fabricated a bread-board time resolved fluorescence system that could detect a concentration of Prostate Specific Antigen t-PSA) at clinically meaningful level in plasma as well as in whole blood sample. We chose Europium chelates as the fluorescence markers to attach to the PSA for its long decay lifetime and relative photostability. We have simplified the electronic circuits considerably by employing a MCS. With this setup, we have successfully proved that PSA concentration of 4pg/mL can be detected with acceptable reliability.

  16. Tumour and immune cell dynamics explain the PSA bounce after prostate cancer brachytherapy

    PubMed Central

    Yamamoto, Yoichiro; Offord, Chetan P; Kimura, Go; Kuribayashi, Shigehiko; Takeda, Hayato; Tsuchiya, Shinichi; Shimojo, Hisashi; Kanno, Hiroyuki; Bozic, Ivana; Nowak, Martin A; Bajzer, Željko; Dingli, David

    2016-01-01

    Background: Interstitial brachytherapy for localised prostate cancer may be followed by transient increases in prostate-specific antigen (PSA) that resolve without therapy. Such PSA bounces may be associated with an improved outcome but often cause alarm in the patient and physician, and have defied explanation. Methods: We developed a mathematical model to capture the interactions between the tumour, radiation and anti-tumour immune response. The model was fitted to data from a large cohort of patients treated exclusively with interstitial brachytherapy. Immunohistological analysis for T-cell infiltration within the same tumours was also performed. Results: Our minimal model captures well the dynamics of the tumour after therapy, and suggests that a strong anti-tumour immune response coupled with the therapeutic effect of radiation on the tumour is responsible for the PSA bounce. Patients who experience a PSA bounce had a higher density of CD3 and CD8 cells within the tumour that likely contribute to the PSA bounce and the overall better outcomes observed. Conclusions: Our observations provide a novel and unifying explanation for the PSA bounce in patients with early prostate cancer and also have implications for the use of immune-based therapies in such patients to improve outcomes. PMID:27404586

  17. Predictive value of [-2]propsa (p2psa) and its derivatives for the prostate cancer detection in the 2.0 to 10.0ng/mL PSA range

    PubMed Central

    Vukovic, I.; Djordjevic, D.; Bojanic, N.; Babic, U.; Soldatovic, I.

    2017-01-01

    ABSTRACT Introduction To assess predictive value of new tumor markers, precursor of prostate specific antigen (p2PSA) and its derivates-%p2PSA and prostate health index (PHI) in detection of patients with indolent and aggressive prostate cancer (PC) in a subcohort of man whose total PSA ranged from 2 to 10ng/mL. Materials and Methods This cross-sectional study included 129 consecutive male patients aged over 50 years, with no previous history of PC and with normal digital rectal examination findings, but with serum PSA in interval between 2 and 10ng/mL. All patients underwent standard transrectal ultrasonography guided prostate biopsy for the first time. For all patients, serum PSA, free PSA (fPSA) and p2PSA were measured and PHI and %p2PSA were calculated. Results PHI and %p2PSA levels were significanlty higher in patients with PC compared to those without this malignancy. The same findings have been observed in group of patients with Gleason score ≥7 compared to those with Gleason score <7. ROC analysis reveled the highest area under the curve with these two markers. Multivariate logistic regression showed significant improvement in PC detection and its agressive form (assumed as Gleason score ≥7). Conclusions New markers, derivates of p2PSA (especially %p2PSA and PHI), represente potentially very important clinical tool for predicting presence of PC, and even more important, to discriminate patients with Gleason score <7 from those with Gleason score ≥7 with total PSA in range from 2 to 10ng/mL. PMID:28124526

  18. Alteration, adsorption and nucleation processes on clay-water interfaces: Mechanisms for the retention of uranium by altered clay surfaces on the nanometer scale

    NASA Astrophysics Data System (ADS)

    Schindler, Michael; Legrand, Christine A.; Hochella, Michael F.

    2015-03-01

    Nano-scale processes on the solid-water interface of clay minerals control the mobility of metals in the environment. These processes can occur in confined pore spaces of clay buffers and barriers as well as in contaminated sediments and involve a combination of alteration, adsorption and nucleation processes of multiple species and phases. This study characterizes nano-scale processes on the interface between clay minerals and uranyl-bearing solution near neutral pH. Samples of clay minerals with a contact pH of ∼6.7 are collected from a U mill and mine tailings at Key Lake, Saskatchewan, Canada. The tailings material contains Cu-, As-, Co-, Mo-, Ni-, Se-bearing polymetallic phases and has been deposited with a surplus of Ca(OH)2 and Na2CO3 slaked lime. Small volumes of mill-process solutions containing sulfuric acid and U are occasionally discharged onto the surface of the tailings and are neutralized after discharge by reactions with the slaked lime. Transmission electron microscopy (TEM) in combination with the focused ion beam (FIB) technique and other analytical methods (SEM, XRD, XRF and ICP-OES) are used to characterize the chemical and mineralogical composition of phases within confined pore spaces of the clay minerals montmorillonite and kaolinite and in the surrounding tailings material. Alteration zones around the clay minerals are characterized by different generations of secondary silicates containing variable proportions of adsorbed uranyl- and arsenate-species and by the intergrowth of the silicates with the uranyl-minerals cuprosklodowskite, Cu[(UO2)2(SiO3OH)2](H2O)6 and metazeunerite, Cu[(UO2)(AsO4)2](H2O)8. The majority of alteration phases such as illite, illite-smectite, kaolinite and vermiculite have been most likely formed in the sedimentary basin of the U-ore deposit and contain low amounts of Fe (<5 at.%). Iron-enriched Al-silicates or illite-smectites (Fe >10 at.%) formed most likely in the limed tailings at high contact pH (∼10.5) and

  19. Structural plasticity of interneurons in the adult brain: role of PSA-NCAM and implications for psychiatric disorders.

    PubMed

    Nacher, Juan; Guirado, Ramon; Castillo-Gómez, Esther

    2013-06-01

    Neuronal structural plasticity is known to have a major role in cognitive processes and in the response of the CNS to aversive experiences. This type of plasticity involves processes ranging from neurite outgrowth/retraction or dendritic spine remodeling, to the incorporation of new neurons to the established circuitry. However, the study of how these structural changes take place has been focused mainly on excitatory neurons, while little attention has been paid to interneurons. The exploration of these plastic phenomena in interneurons is very important, not only for our knowledge of CNS physiology, but also for understanding better the etiology of different psychiatric and neurological disorders in which alterations in the structure and connectivity of inhibitory networks have been described. Here we review recent work on the structural remodeling of interneurons in the adult brain, both in basal conditions and after chronic stress or sensory deprivation. We also describe studies from our laboratory and others on the putative mediators of this interneuronal structural plasticity, focusing on the polysialylated form of the neural cell adhesion molecule (PSA-NCAM). This molecule is expressed by some interneurons in the adult CNS and, through its anti-adhesive and insulating properties, may participate in the remodeling of their structure. Finally, we review recent findings on the possible implication of PSA-NCAM on the remodeling of inhibitory neurons in certain psychiatric disorders and their treatments.

  20. Adsorption of phenolic compound by aged-refuse.

    PubMed

    Xiaoli, Chai; Youcai, Zhao

    2006-09-01

    The adsorption of phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol by aged-refuse has been studied. Adsorption isotherms have been determined for phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol and the data fits well to the Freundlich equation. The chlorinated phenols are absorbed more strongly than the phenol and the adsorption capacity has an oblivious relationship with the numbers and the position of chlorine subsistent. The experiment data suggests that both the partition function and the chemical adsorption involve in the adsorption process. Pseudo-first-order and pseudo-second-order model were applied to investigate the kinetics of the adsorption and the results show that it fit the pseudo-second-order model. More than one step involves in the adsorption process and the overall rate of the adsorption process appears to be controlled by the chemical reaction. The thermodynamic analysis indicates that the adsorption is spontaneous and endothermic.

  1. Effect of a new regeneration process by adsorption-coagulation and flocculation on the physicochemical properties and the detergent efficiency of regenerated cleaning solutions.

    PubMed

    Blel, Walid; Dif, Mehdi; Sire, Olivier

    2015-05-15

    Reprocessing soiled cleaning-in-place (CIP) solutions has large economic and environmental costs, and it would be cheaper and greener to recycle them. In food industries, recycling of CIP solutions requires a suitable green process engineered to take into account the extreme physicochemical conditions of cleaning while not altering the process efficiency. To this end, an innovative treatment process combining adsorption-coagulation with flocculation was tested on multiple recycling of acid and basic cleaning solutions. In-depth analysis of time-course evolutions was carried out in the physicochemical properties (concentration, surface tension, viscosity, COD, total nitrogen) of these solutions over the course of successive regenerations. Cleaning and disinfection efficiencies were assessed based on both microbiological analyses and organic matter detachment and solubilization from fouled stainless steel surfaces. Microbiological analyses using a resistant bacterial strain (Bacillus subtilis spores) highlighted that solutions regenerated up to 20 times maintained the same bactericidal efficiency as de novo NaOH solutions. The cleanability of stainless steel surfaces showed that regenerated solutions allow better surface wettability, which goes to explain the improved detachment and solubilization found on different types of organic and inorganic fouling.

  2. Protein Adsorption in Three Dimensions

    PubMed Central

    Vogler, Erwin A.

    2011-01-01

    Recent experimental and theoretical work clarifying the physical chemistry of blood-protein adsorption from aqueous-buffer solution to various kinds of surfaces is reviewed and interpreted within the context of biomaterial applications, especially toward development of cardiovascular biomaterials. The importance of this subject in biomaterials surface science is emphasized by reducing the “protein-adsorption problem” to three core questions that require quantitative answer. An overview of the protein-adsorption literature identifies some of the sources of inconsistency among many investigators participating in more than five decades of focused research. A tutorial on the fundamental biophysical chemistry of protein adsorption sets the stage for a detailed discussion of the kinetics and thermodynamics of protein adsorption, including adsorption competition between two proteins for the same adsorbent immersed in a binary-protein mixture. Both kinetics and steady-state adsorption can be rationalized using a single interpretive paradigm asserting that protein molecules partition from solution into a three-dimensional (3D) interphase separating bulk solution from the physical-adsorbent surface. Adsorbed protein collects in one-or-more adsorbed layers, depending on protein size, solution concentration, and adsorbent surface energy (water wettability). The adsorption process begins with the hydration of an adsorbent surface brought into contact with an aqueous-protein solution. Surface hydration reactions instantaneously form a thin, pseudo-2D interface between the adsorbent and protein solution. Protein molecules rapidly diffuse into this newly-formed interface, creating a truly 3D interphase that inflates with arriving proteins and fills to capacity within milliseconds at mg/mL bulk-solution concentrations CB. This inflated interphase subsequently undergoes time-dependent (minutes-to-hours) decrease in volume VI by expulsion of either-or-both interphase water and

  3. Carbon dioxide separation using adsorption with steam regeneration

    DOEpatents

    Elliott, Jeannine Elizabeth; Copeland, Robert James; Leta, Daniel P.; McCall, Patrick P.; Bai, Chuansheng; DeRites, Bruce A.

    2016-11-29

    A process for separating a carbon dioxide from a gas stream is disclosed. The process can include passing the gas stream over a sorbent that adsorbs the carbon dioxide by concentration swing adsorption and adsorptive displacement. The sorbent can be regenerated and the carbon dioxide recaptured by desorbing the carbon dioxide from the sorbent using concentration swing adsorption and desorptive displacement. A carbon dioxide separation system is also disclosed. Neither the system nor the process rely on temperature swing or pressure swing adsorption.

  4. COS Imaging TA and Spectroscopic WCA-PSA/BOA offset verifications

    NASA Astrophysics Data System (ADS)

    Penton, Steven

    2012-10-01

    This program builds upon the monitoring and calibration of the FGSs. The list of proposals, cycles, and the order in which the alignment is checked is given below.11878->12399->12781->13171C17->C18->C19->C20STIS->WFC3->ACS->COSVisit 01 of the C20 SIAF verification program, 13171, executed on Mar 2, 2012, and Visit 02 is scheduled for Sep 1, 2103. This program performs a PSA/MIRRORA ACQ/IMAGE on a target that should already be centered in the aperture. This verifies the COS NUV PSA aperture position in the SIAF. After this PSA+MIRRORA ACQ/IMAGE, a PSA+MIRRORB ACQ/IMAGE is then performed. This exposure bootstraps the PSA+MIRRORB centering to the PSA+MIRROR SIAF verification. This allows us to monitor the properties of the PSA+MIRRORB image in a controlled way on a centered target. No spectra are taken in 13171 due to time constrains.This program extends the SIAF verification of 13171 to the other two ACQ/IMAGE combinations {BOA+MIRRORA & BOA+MIRRORB} by bootstraping from the PSA+MIRRORB verification of 13171.Visit 1 of this program begins with a PSA+MIRRORB NUV ACQ/IMAGE followed by a BOA+MIRRORA ACQ/IMAGE. Both observations are high S/N to get the most accurate centering information possible. The program then takes a PSA+MIRRORB IMAGE to ensure that we are still properly centered. We prefer that Visit 01 of this program executes after Visit 02 of 13171, but more than 17, but less than 45 days after to ensure that no long term instrument or telescope focus changes impart our results.After the Imaging verification Visit 1 of this program will obtain a S/N > 60 NUV spectrum using the most popular NUV grating {G230L, G185M, & G285M}, and FUV Spectra using G130M/1309 and G140L/1280. This allows the direct verification of the NUV and FUV WCA-to-PSA cross-dispersion offsets used by ACQ/PEAKXD.Visit 02 of this program follows the style of Visit 01, but the initial ACQ/IMAGE is a BOA+MIRRORA and the second ACQ/IMAGE is BOA/MIRRORB. Visit 02 should occur after Visit 01 by

  5. Enhancement of soil retention for phenanthrene in binary cationic gemini and nonionic surfactant mixtures: characterizing two-step adsorption and partition processes through experimental and modeling approaches.

    PubMed

    Zhao, Shan; Huang, Gordon; An, Chunjiang; Wei, Jia; Yao, Yao

    2015-04-09

    The enhancement of soil retention for phenanthrene (PHE) through the addition of a binary mixture of cationic gemini (12-2-12) and nonionic surfactants (C12E10) was investigated. The maximum apparent sorption coefficient Kd(*) reached 4247.8 mL/g through the addition of mixed 12-2-12 gemini and C12E10 surfactants, which was markedly higher than the summed individual results in the presence of individual 12-2-12 gemini (1148.6 mL/g) or C12E10 (210.0 mL/g) surfactant. However, the sorption of 12-2-12 gemini was inhibited by the increasing C12E10 dose; and a higher initial 12-2-12 gemini dose showed a higher "desorption" rate. The present study also addressed the sorption behavior of the single 12-2-12 gemini surfactant at the soil/aqueous interface. The sorption isotherm was divided into two steps to elucidate the sorption process; and the sorption schematics were proposed to elaborate the growth of surfactant aggregates corresponding to the various steps of the sorption isotherm. Finally, a two-step adsorption and partition model (TAPM) was developed to simulate the sorption process. Analysis of the equilibrium data indicated that the sorption isotherms of 12-2-12 gemini fitted the TAPM model better. Thermodynamic calculations confirmed that the 12-2-12 gemini sorption at the soil/aqueous interface was spontaneous and exothermic from 288 to 308K.

  6. Distinctive PSA-NCAM and NCAM Hallmarks in Glutamate-Induced Dendritic Atrophy and Synaptic Disassembly

    PubMed Central

    Podestá, María Fernanda; Yam, Patricia; Codagnone, Martín Gabriel; Uccelli, Nonthué Alejandra; Colman, David; Reinés, Analía

    2014-01-01

    Dendritic and synapse remodeling are forms of structural plasticity that play a critical role in normal hippocampal function. Neural cell adhesion molecule (NCAM) and its polysialylated form (PSA-NCAM) participate in neurite outgrowth and synapse formation and plasticity. However, it remains unclear whether they contribute to dendritic retraction and synaptic disassembly. Cultured hippocampal neurons exposed to glutamate (5 µM) showed a reduced MAP-2 (+) area in the absence of neuronal death 24 h after the insult. Concomitantly, synapse loss, revealed by decreased synaptophysin and post-synaptic density-95 cluster number and area, together with changes in NCAM and PSA-NCAM levels were found. Dendritic atrophy and PSA-NCAM reduction proved NMDA-receptor dependent. Live-imaging experiments evidenced dendritic atrophy 4 h after the insult; this effect was preceded by smaller NCAM clusters (1 h) and decreased surface and total PSA-NCAM levels (3 h). Simultaneously, total NCAM cluster number and area remained unchanged. The subsequent synapse disassembly (6 h) was accompanied by reductions in total NCAM cluster number and area. A PSA mimetic peptide prevented both the dendritic atrophy and the subsequent synaptic changes (6 h) but had no effect on the earliest synaptic remodeling (3 h). Thus, NCAM-synaptic reorganization and PSA-NCAM level decrease precede glutamate-induced dendritic atrophy, whereas the NCAM level reduction is a delayed event related to synapse loss. Consequently, distinctive stages in PSA-NCAM/NCAM balance seem to accompany glutamate-induced dendritic atrophy and synapse loss. PMID:25279838

  7. The new Planetary Science Archive (PSA): Exploration and discovery of scientific datasets from ESA's planetary missions

    NASA Astrophysics Data System (ADS)

    Martinez, Santa; Besse, Sebastien; Heather, Dave; Barbarisi, Isa; Arviset, Christophe; De Marchi, Guido; Barthelemy, Maud; Docasal, Ruben; Fraga, Diego; Grotheer, Emmanuel; Lim, Tanya; Macfarlane, Alan; Rios, Carlos; Vallejo, Fran; Saiz, Jaime; ESDC (European Space Data Centre) Team

    2016-10-01

    The Planetary Science Archive (PSA) is the European Space Agency's (ESA) repository of science data from all planetary science and exploration missions. The PSA provides access to scientific datasets through various interfaces at http://archives.esac.esa.int/psa. All datasets are scientifically peer-reviewed by independent scientists, and are compliant with the Planetary Data System (PDS) standards. The PSA is currently implementing a number of significant improvements, mostly driven by the evolution of the PDS standard, and the growing need for better interfaces and advanced applications to support science exploitation. The newly designed PSA will enhance the user experience and will significantly reduce the complexity for users to find their data promoting one-click access to the scientific datasets with more specialised views when needed. This includes a better integration with Planetary GIS analysis tools and Planetary interoperability services (search and retrieve data, supporting e.g. PDAP, EPN-TAP). It will be also up-to-date with versions 3 and 4 of the PDS standards, as PDS4 will be used for ESA's ExoMars and upcoming BepiColombo missions. Users will have direct access to documentation, information and tools that are relevant to the scientific use of the dataset, including ancillary datasets, Software Interface Specification (SIS) documents, and any tools/help that the PSA team can provide. A login mechanism will provide additional functionalities to the users to aid / ease their searches (e.g. saving queries, managing default views). This contribution will introduce the new PSA, its key features and access interfaces.

  8. Development of a process for large-scale purification of C-phycocyanin from Synechocystis aquatilis using expanded bed adsorption chromatography.

    PubMed

    Ramos, Amparo; Acién, F Gabriel; Fernández-Sevilla, José M; González, Cynthia V; Bermejo, Ruperto

    2011-03-01

    In this paper a large and scaleable method for purification of C-phycocyanin (C-PC) from the cyanobacteria Synechocystis aquatilis has been developed. Phycobiliproteins are extracted from the cells by osmotic shock and separated by passing the centrifuged cell suspension through an expanded bed adsorption chromatography (EBAC) column using Streamline-DEAE as adsorbent. The eluted C-PC rich solution is finally purified by packed-bed chromatography using DEAE-cellulose. Optimal extraction is achieved using phosphate 0.05 M buffer pH 7.0 twice. The operation of EBAC is optimized on a small scale using a column of 15 mm internal diameter (I.D.). The optimal conditions are a sample load of 4.9 mg C-PC/mL adsorbent, an expanded bed volume twice the settled bed volume and a sample viscosity of 1.020 mP. The EBAC process is then scaled up by increasing the column I.D. (15, 25, 40, 60 and 90 mm) and the success of the scale-up process is verified by determining the protein breakthrough capacity and product recovery. The yield of the EBAC step is in the range of 90-93% for every column diameter. To obtain pure C-PC, conventional ion-exchange chromatography with DEAE-cellulose is utilized and a yield of 74% is obtained. The overall yield of the process, comprising all steps, is 69%. The purification steps are monitored using SDS-PAGE and the purity of recovered C-PC is confirmed by absorption and emission spectroscopy and RP-HPLC. Results show that EBAC method is a scalable technology that allows large quantities of C-PC to be obtained without product loss, maintaining a high protein recovery while reducing both processing cost and time.

  9. Early Interactions of Rhizobium leguminosarum bv. phaseoli and Bean Roots: Specificity in the Process of Adsorption and Its Requirement of Ca(sup2+) and Mg(sup2+) Ions

    PubMed Central

    Lodeiro, A. R.; Lagares, A.; Martinez, E. N.; Favelukes, G.

    1995-01-01

    Roots of Phaseolus vulgaris L. were incubated with dilute suspensions (1 x 10(sup3) to 3 x 10(sup3) bacteria ml(sup-1)) of an antibiotic-resistant indicator strain of Rhizobium leguminosarum bv. phaseoli in mineral medium and washed four times by a standardized procedure prior to quantitation of adsorption (G. Caetano-Anolles and G. Favelukes, Appl. Environ. Microbiol. 52:371-376, 1986). The population of rhizobia remaining adsorbed on roots after washing was homogeneous, as indicated by the first-order course of its desorption by hydrodynamic shear. Rhizobia were maximally active for adsorption in the early stationary phase of growth. The process leading to adsorption was rapid, without an initial lag, and slowed down after 1 h. Adsorption of the indicator strain at 10(sup3) bacteria ml(sup-1) was inhibited to different extents in the presence of 10(sup3) to 10(sup8) antibiotic-sensitive competitor rhizobia ml(sup-1). After a steep rise above 10(sup4) bacteria ml(sup-1), inhibition by heterologous competitors in the concentration range of 10(sup5) to 10(sup7) bacteria ml(sup-1) was markedly less than by homologous strains, while at 10(sup8) bacteria ml(sup-1) it approached the high level of inhibition by the latter. At 10(sup7) bacteria ml(sup-1), all of the heterologous strains tested were consistently less inhibitory than homologous competitors (P < 0.001). These differences in competitive behavior indicate that in the process of adsorption of R. leguminosarum bv. phaseoli to its host bean roots, different modes of adsorption occur and that some of these modes are specific for the microsymbiont (as previously reported for the alfalfa system [G. Caetano-Anolles and G. Favelukes, Appl. Environ. Microbiol. 52:377-381, 1986]). Moreover, whereas the nonspecific process occurred either in the absence or in the presence of Ca(sup2+) and Mg(sup2+) ions, expression of specificity was totally dependent on the presence of those cations. R. leguminosarum bv. phaseoli

  10. A lab-in-a-briefcase for rapid prostate specific antigen (PSA) screening from whole blood.

    PubMed

    Barbosa, Ana I; Castanheira, Ana P; Edwards, Alexander D; Reis, Nuno M

    2014-08-21

    We present a new concept for rapid and fully portable prostate specific antigen (PSA) measurements, termed "lab-in-a-briefcase", which integrates an affordable microfluidic ELISA platform utilising a melt-extruded fluoropolymer microcapillary film (MCF) containing an array of 10 200 μm internal diameter capillaries, a disposable multi-syringe aspirator (MSA), a sample tray pre-loaded with all of the required immunoassay reagents, and a portable film scanner for colorimetric signal digital quantification. Each MSA can perform 10 replicate microfluidic immunoassays on 8 samples, allowing 80 measurements to be made in less than 15 minutes based on semi-automated operation, without the need of additional fluid handling equipment. The assay was optimised for the measurement of a clinically relevant range of PSA of 0.9 to 60.0 ng ml(-1) in 15 minutes with CVs on the order of 5% based on intra-assay variability when read using a consumer flatbed film scanner. The PSA assay performance in the MSA remained robust in undiluted or 1 : 2 diluted human serum or whole blood, and the matrix effect could simply be overcome by extending sample incubation times. The PSA "lab-in-a-briefcase" is particularly suited to a low-resource health setting, where diagnostic labs and automated immunoassay systems are not accessible, by allowing PSA measurement outside the laboratory using affordable equipment.

  11. Wash-free magnetic immunoassay of the PSA cancer marker using SERS and droplet microfluidics.

    PubMed

    Gao, Rongke; Cheng, Ziyi; deMello, Andrew J; Choo, Jaebum

    2016-03-21

    We report a novel wash-free magnetic immunoassay technique for prostate-specific antigen (PSA) that uses a surface-enhanced Raman scattering (SERS)-based microdroplet sensor. The magnetic bar embedded in a droplet-based microfluidic system segregates the free and bound SERS tags by splitting the droplets into two smaller parts. The presence of PSA targets leads more SERS tags to immunocomplex in one droplet so that fewer SERS tags remain in another supernatant solution droplet. Thus, SERS signal measurement enables the quantitative evaluation of PSA markers. This approach can provide a rapid and sensitive assay that is applicable for PSA cancer markers in serum without any washing. Specifically, SERS signals were measured at 174 droplets per minute and averaged for quantitative evaluation of PSA. The limit of detection (LOD) determined by our SERS-based microdroplet sensor was estimated to be below 0.1 ng mL(-1), which is significantly below the clinical cut-off value for the diagnosis of prostate cancer. In addition, because the entire assay can be carried out automatically, only a minimal amount of sample is needed. Accordingly, the approach is expected to be useful as a potential clinical tool for the early diagnosis of prostate cancer.

  12. The effect of the USPSTF PSA screening recommendation on prostate cancer incidence patterns in the USA.

    PubMed

    Fleshner, Katherine; Carlsson, Sigrid V; Roobol, Monique J

    2017-01-01

    Guidelines regarding recommendations for PSA screening for early detection of prostate cancer are conflicting. In 2012, the United States Preventive Services Task Force (USPSTF) assigned a grade of D (recommending against screening) for men aged ≥75 years in 2008 and for men of all ages in 2012. Understanding temporal trends in rates of screening before and after the 2012 recommendation in terms of usage patterns in PSA screening, changes in prostate cancer incidence and biopsy patterns, and how the recommendation has influenced physician's and men's attitudes about PSA screening and subsequent ordering of other screening tests is essential within the scope of prostate cancer screening policy. Since the 2012 recommendation, rates of PSA screening decreased by 3-10% in all age groups and across most geographical regions of the USA. Rates of prostate biopsy and prostate cancer incidence have declined in unison, with a shift towards tumours being of higher grade and stage upon detection. Despite the recommendation, some physicians report ongoing willingness to screen appropriately selected men, and many men report intending to continue to ask for the PSA test from their physician. In the coming years, we expect to have an improved understanding of whether these decreased rates of screening will affect prostate cancer metastasis and mortality.

  13. Adsorption and isotopic fractionation of Xe

    NASA Technical Reports Server (NTRS)

    Bernatowicz, T. J.; Podosek, F. A.

    1986-01-01

    A theoretical description of the mechanisms of isotopic fractionation arising during adsorption of noble gases in a Henry's Law pressure regime is given. Experimental data on the isotopic composition of Xe adsorbed on activated charcoal in the temperature range 220 K to 350 K are presented. Both theoretical considerations and the experimental data indicate that equilibrium adsorption does not significantly alter the isotopic structure of adsorbed structure of adsorbed noble gases. Therefore, if adsorption is responsible for the elemental noble gas pattern in meteorites and the earth, the heavy noble gas isotopic fractionation between them must have been produced prior to and by a different process than equilibrium adsorption.

  14. Electrokinetic investigation of surfactant adsorption.

    PubMed

    Bellmann, C; Synytska, A; Caspari, A; Drechsler, A; Grundke, K

    2007-05-15

    Fuerstenau [D.W. Fuerstenau, in: M.L. Hair (Ed.), Dekker, New York, 1971, p. 143] has already discussed the role of hydrocarbon chain of surfactants, the effect of alkyl chain length, chain structure and the pH of the solution on the adsorption process of surfactants. Later Kosmulski [M. Kosmulski, Chemical Properties of Material Surfaces, Surfactant Science Series, vol. 102, Dekker, New York, Basel, 2001] included the effect of surfactant concentration, equilibration time, temperature and electrolyte in his approaches. Certainly, the character of the head groups of the surfactant and the properties of the adsorbent surface are the basis for the adsorption process. Different surfactants and adsorbents cause different adsorption mechanisms described firstly by Rosen [M.J. Rosen, Surfactants and Interfacial Phenomena, second ed., Wiley, New York, 1989]. These adsorption mechanisms and their influencing factors were studied by electrokinetic investigations. Here only changes of the charges at the surfaces could be detected. To control the results of electrokinetic investigations they were compared with results from ellipsometric measurements. In the case of surfactant adsorption the chain length was vitally important. It could be shown by the adsorption of alkyl trimethyl ammonium bromides onto polymer films spin coated at wafer surfaces. The influence of the chain length depending on surface properties of the polymer film was studied. Streaming potential measurements were applied for these investigations. The obtained results enabled us to calculate the molar cohesive free energy per mol of CH2-group in the alkaline chain of the surfactant if all other specific adsorption effects were neglected.

  15. Efficient CdSe quantum dot-sensitized solar cells prepared by an improved successive ionic layer adsorption and reaction process.

    PubMed

    Lee, Hyojoong; Wang, Mingkui; Chen, Peter; Gamelin, Daniel R; Zakeeruddin, Shaik M; Grätzel, Michael; Nazeeruddin, Md K

    2009-12-01

    In pursuit of efficient quantum dot (QD)-sensitized solar cells based on mesoporous TiO(2) photoanodes, a new procedure for preparing selenide (Se(2-)) was developed and used for depositing CdSe QDs in situ over TiO(2) mesopores by the successive ionic layer adsorption and reaction (SILAR) process in ethanol. The sizes and density of CdSe QDs over TiO(2) were controlled by the number of SILAR cycles applied. After some optimization of these QD-sensitized TiO(2) films in regenerative photoelectrochemical cells using a cobalt redox couple [Co(o-phen)(3)(2+/3+)], including addition of a final layer of CdTe, over 4% overall efficiencies were achieved at 100 W/m(2) with about 50% IPCE at its maximum. Light-harvesting properties and transient voltage decay/impedance measurements confirmed that CdTe-terminated CdSe QD cells gave better charge-collection efficiencies and kinetic parameters than corresponding CdSe QD cells. In a preliminary study, a CdSe(Te) QD-sensitized TiO(2) film was combined with an organic hole conductor, spiro-OMeTAD, and shown to exhibit a promising efficiency of 1.6% at 100 W/m(2) in inorganic/organic hybrid all-solid-state cells.

  16. Adsorption of radionuclides on minerals studies illustrating the effect of solid phase selectivity and of mechanisms controlling sorption processes

    SciTech Connect

    Netus, B.

    1996-02-01

    Currently, extensive research is being done on the geochemistry of Yucca Mountain, Nevada. The purpose of this research is to determine whether this location would be suitable as a permanent high-level radioactive waste repository. Site characterization tests must prove that Yucca Mountains` geology will safely isolate radioactive waste from the environment for at least 10,000 years before approval is granted. In order for this to occur, it is necessary to study the sorptive properties of the host rock, and its selectivity in sorption of solutions containing multiple radionuclides. Validation of this must occur, because in the case of a catastrophic leak, the host rock must have properties that will retard the migration of radionuclides. Columnar experimental techniques were employed using goethite, (a hydrous iron oxide), beidellite (clay mineral), & {open_quotes}nonscents{close_quotes} (a zeolitized volcanic tuff) as sorbents. These sorbents were used to measure the isotherms of an identical binary solution (Ni-Sr) to illustrate the selectivity that occurs in different minerals. In beidellite, the sorption process was ideal, while for {open_quotes}nonscents{close_quotes} there was a strong preference for Sr{sup 2+}. The sorption process was modeled (Ni-Sr {open_quotes}Nonscents{close_quotes}) using ion exchange theory as the mechanism. In goethite, the sorption of Ni-Sr showed a complete preference for Ni{sup 2+} at a pH of 7. In various other systems for goethite. Co-Ni (pH=7) was ideal (no selectivity) where the ratios in the solid and solution phases were relatively equal. Conversely in the case of the Pb-Ni system, the Pb{sup 2+} ion predominated completely in the solidphase over Ni{sup 2+} at a pH of 5.5. Noting the strong effect of pH on the sorption process in goethite, the selectivity could not necessarily be credited to ion-exchange because of possible exclusion from charged sites at low pH values.

  17. 'PSA-SPN' - A Parameter Sensitivity Analysis Method Using Stochastic Petri Nets: Application to a Production Line System

    SciTech Connect

    Labadi, Karim; Saggadi, Samira; Amodeo, Lionel

    2009-03-05

    The dynamic behavior of a discrete event dynamic system can be significantly affected for some uncertain changes in its decision parameters. So, parameter sensitivity analysis would be a useful way in studying the effects of these changes on the system performance. In the past, the sensitivity analysis approaches are frequently based on simulation models. In recent years, formal methods based on stochastic process including Markov process are proposed in the literature. In this paper, we are interested in the parameter sensitivity analysis of discrete event dynamic systems by using stochastic Petri nets models as a tool for modelling and performance evaluation. A sensitivity analysis approach based on stochastic Petri nets, called PSA-SPN method, will be proposed with an application to a production line system.

  18. Effects of adsorption and roughness upon the collision processes at the convertor surface of a plasma sputter negative ion sourcea)

    NASA Astrophysics Data System (ADS)

    Kenmotsu, T.; Wada, M.

    2012-02-01

    Atomic collision processes associated with surface production of negative hydrogen ions (H-) by particle reflection at molybdenum surface immersed in hydrogen plasma have been investigated. To calculate sputtering yields of Cs, as well as energy spectra and angular distributions of reflected hydrogen atoms from molybdenum surface by H+ ion and Cs+ ion bombardments, a Monte Carlo simulation code ACAT (Atomic Collision in Amorphous Target) was run with the corresponding surface conditions. A fractal surface model has been developed and adopted to ACAT for evaluating the effect due to roughness of target material. The results obtained with ACAT have indicated that the retention of hydrogen atoms leads to the reduction in sputtering yields of Cs, and the surface roughness does largely affect the sputtering yields of Cs.

  19. Effects of adsorption and roughness upon the collision processes at the convertor surface of a plasma sputter negative ion source

    SciTech Connect

    Kenmotsu, T.; Wada, M.

    2012-02-15

    Atomic collision processes associated with surface production of negative hydrogen ions (H{sup -}) by particle reflection at molybdenum surface immersed in hydrogen plasma have been investigated. To calculate sputtering yields of Cs, as well as energy spectra and angular distributions of reflected hydrogen atoms from molybdenum surface by H{sup +} ion and Cs{sup +} ion bombardments, a Monte Carlo simulation code ACAT (Atomic Collision in Amorphous Target) was run with the corresponding surface conditions. A fractal surface model has been developed and adopted to ACAT for evaluating the effect due to roughness of target material. The results obtained with ACAT have indicated that the retention of hydrogen atoms leads to the reduction in sputtering yields of Cs, and the surface roughness does largely affect the sputtering yields of Cs.

  20. Adsorption of geosmin and 2-methylisoborneol onto powdered activated carbon at non-equilibrium conditions: influence of NOM and process modelling.

    PubMed

    Zoschke, Kristin; Engel, Christina; Börnick, Hilmar; Worch, Eckhard

    2011-10-01

    The adsorption of the taste and odour (T&O) compounds geosmin and 2-methylisoborneol (2-MIB) onto powdered activated carbon (PAC) has been studied under conditions which are typical for a drinking water treatment plant that uses reservoir water for drinking water production. The reservoir water as well as the pre-treated water (after flocculation) contains NOM that competes with the trace compounds for the adsorption sites on the carbon surface. Although the DOC concentrations in the reservoir water and in the pre-treated water were different, no differences in the competitive adsorption could be seen. By using two special characterisation methods for NOM (adsorption analysis, LC/OCD) it could be proved that flocculation removes only NOM fractions which are irrelevant for competitive adsorption. Different model approaches were applied to describe the competitive adsorption of the T&O compounds and NOM, the tracer model, the equivalent background compound model, and the simplified equivalent background compound model. All these models are equilibrium models but in practice the contact time in flow-through reactors is typically shorter than the time needed to establish the adsorption equilibrium. In this paper it is demonstrated that the established model approaches can be used to describe competitive adsorption of T&O compounds and NOM also under non-equilibrium conditions. The results of the model applications showed that in particular the simplified equivalent background compound model is a useful tool to determine the PAC dosage required to reduce the T&O compounds below the threshold concentration.

  1. Modeling the adsorption of mixed gases based on pure gas adsorption properties

    NASA Astrophysics Data System (ADS)

    Tzabar, N.; Holland, H. J.; Vermeer, C. H.; ter Brake, H. J. M.

    2015-12-01

    Sorption-based Joule-Thomson (JT) cryocoolers usually operate with pure gases. A sorption-based compressor has many benefits; however, it is limited by the pressure ratios it can provide. Using a mixed-refrigerant (MR) instead of a pure refrigerant in JT cryocoolers allows working at much lower pressure ratios. Therefore, it is attractive using MRs in sorption- based cryocoolers in order to reduce one of its main limitations. The adsorption of mixed gases is usually investigated under steady-state conditions, mainly for storage and separation processes. However, the process in a sorption compressor goes through various temperatures, pressures and adsorption concentrations; therefore, it differs from the common mixed gases adsorption applications. In order to simulate the sorption process in a compressor a numerical analysis for mixed gases is developed, based on pure gas adsorption characteristics. The pure gas adsorption properties have been measured for four gases (nitrogen, methane, ethane, and propane) with Norit-RB2 activated carbon. A single adsorption model is desired to describe the adsorption of all four gases. This model is further developed to a mixed-gas adsorption model. In future work more adsorbents will be tested using these four gases and the adsorption model will be verified against experimental results of mixed-gas adsorption measurements.

  2. Clinically insignificant improvement of prostate cancer prediction by addition of sex steroid hormones and SHBG serum levels to serum PSA, fPSA%, and age in a screening setting.

    PubMed

    Heidegger, Isabel; Popovscaia, Marina; Ramoner, Reinhold; Schäfer, Georg; Stenzel, Birgit; Bektic, Jasmin; Horninger, Wolfgang; Klocker, Helmut

    2012-10-01

    Abstract Various findings implicate sex hormones in prostate growth and development and also in prostate carcinogenesis. We investigated if addition of sex steroid hormone and sex hormone binding globulin (SHBG) serum levels to standard risk assessment parameters [prostate-specific antigen (PSA), free PSA percentage (fPSA%), and age] improves prostate cancer prediction in a PSA screening setting. Steroid hormones testosterone (T), free testosterone (fT), and estradiol (E2), and binding protein SHBG levels were measured in 762 men undergoing prostate biopsy due to suspect PSA serum levels. Prostate cancer was diagnosed in 286 (37.5%) of these men. Our data confirmed that PSA (mean BE=5.09; mean CA=6.05; p=1.24×10-5), fPSA% (mean BE=22.08; mean CA=18.67; p=1.97×10-7), and age (mean BE=60.64; mean CA=64.5; p=7.05×10-10) differentiate men with cancer (CA) and men with benign disease (BE), such as benign prostate hyperplasia. In addition, SHBG (mean BE=50.3; mean CA=54.9; p=0.008) also differed statistically significantly between these two groups. All hormones except E2 and tumor markers correlated significantly with age (T: ρ=-0.09; fT: ρ=-0.27; SHBG: ρ=0.21; PSA: ρ=0.32; and fPSA%: ρ=0.22). Furthermore, we found that PSA correlates with E2 (ρ=0.08), and fPSA% with SHBG (ρ=0.1) and fT (ρ=-0.09). Addition of hormones and SHBG to a baseline marker model including PSA, fPSA%, and age improved cancer prediction in three multivariate classification methods; however, the improvement was minimal. The best improvement by 0.8% was obtained in the logistic regression model with the addition of T and SHBG or of E2 and SHBG, or in the support vector machine model with the addition of SHBG and all steroid hormones to the combination of standard markers PSA, fPSA%, and age; however, this additional gain of accuracy is too small to justify the additional efforts and costs.

  3. Conceptual adsorption models and open issues pertaining to performance assessment

    SciTech Connect

    Serne, R.J.

    1991-10-01

    Recently several articles have been published that question the appropriateness of the distribution coefficient, Rd, concept to quantify radionuclide migration. Several distinct issues are raised by various critics. In this paper I provide some perspective on issues surrounding the modeling of nuclide retardation. The first section defines adsorption terminology and discusses various adsorption processes. The next section describes five commonly used adsorption conceptual models, specifically emphasizing what attributes that affect adsorption are explicitly accommodated in each model. I also review efforts to incorporate each adsorption model into performance assessment transport computer codes. The five adsorption conceptual models are (1) the constant Rd model, (2) the parametric Rd model, (3) isotherm adsorption models, (4) mass-action adsorption models, and (5) surface-complexation with electrostatics models. The final section discusses the adequacy of the distribution ratio concept, the adequacy of transport calculations that rely on constant retardation factors and the status of incorporating sophisticated adsorption models into transport codes.

  4. Interaction between alpha-calcium sulfate hemihydrate and superplasticizer from the point of adsorption characteristics, hydration and hardening process

    SciTech Connect

    Guan Baohong; Ye Qingqing; Zhang Jiali; Lou Wenbin; Wu Zhongbiao

    2010-02-15

    Superplasticizers (SPs), namely sulfonated melamine formaldehyde (SMF) and polycarboxylate (PC), were independently admixed with alpha-calcium sulfate hemihydrate based plaster to improve the material's performance. SMF and PC gave, respectively, 38% and 25% increases in the 2 h bending strength at the optimum dosages of 0.5 wt.% and 0.3 wt.%, which are determined essentially by the maximum water-reducing efficiency. The peak shift of binding energy of Ca2p{sub 3/2} detected by X-ray photoelectron spectroscopy (XPS) suggests that SPs are chemically adsorbed on gypsum surface. A careful examination of the strength development of set plaster allowed the hydration and hardening process to be divided roughly into five stages. SMF accelerates early hydration, while PC decelerates it. Both SPs allowed similar maximum water reductions, giving a more compact structure and a decrease in total pore volume and average pore diameter, and thus leading to higher strengths in the hardened plasters with SPs.

  5. Development of a quality pedigree process and application to the Duane Arnold Energy Center probabilistic safety assessment. Final report

    SciTech Connect

    Anderson, V.M.; Burns, E.T.; Hughes, E.A.; Stewart, M.A.; Lanc, T.L.

    1996-08-01

    The probabilistic safety assessment (PSA) has become increasingly recognized by the USNRC and the industry as a useful complement to the more traditional deterministic analyses to support plant decision making. The benefits of a living PSA include its use in supporting licensing actions, license renewals, risk management, and integrated safety assessments. EPRI developed and implemented a quality pedigree process for the Duane Arnold Energy Center (DAEC) PSA that can be beneficially and cost-effectively applied at other utilities. The PSA pedigree process described in this report is comprised of a governing administrative PSA control procedure and PSA group internally administered guidelines. Controls are provided for the following PSA areas: personnel responsibilities, group training requirements, review processes, documentation, and maintenance. A number of lessons learned regarding the development and implementation of a pedigree process are also presented. These lessons address the structure of the pedigree process, PSA applications, the PSA review process, effects of the pedigree on PSA inputs, and DAEC plant-specific results. 32 refs.

  6. Removal of diethyl phthalate from water solution by adsorption, photo-oxidation, ozonation and advanced oxidation process (UV/H₂O₂, O₃/H₂O₂ and O₃/activated carbon).

    PubMed

    Medellin-Castillo, Nahum A; Ocampo-Pérez, Raúl; Leyva-Ramos, Roberto; Sanchez-Polo, Manuel; Rivera-Utrilla, José; Méndez-Díaz, José D

    2013-01-01

    The objective of this work was to compare the effectiveness of conventional technologies (adsorption on activated carbon, AC, and ozonation) and technologies based on advanced oxidation processes, AOPs, (UV/H(2)O(2), O(3)/AC, O(3)/H(2)O(2)) to remove phthalates from aqueous solution (ultrapure water, surface water and wastewater). Diethyl phthalate (DEP) was chosen as a model pollutant because of its high water solubility (1,080 mg/L at 293 K) and toxicity. The activated carbons showed a high adsorption capacity to adsorb DEP in aqueous solution (up to 858 mg/g), besides the adsorption mechanism of DEP on activated carbon is governed by dispersive interactions between π electrons of its aromatic ring with π electrons of the carbon graphene planes. The photodegration process showed that the pH solution does not significantly affect the degradation kinetics of DEP and the first-order kinetic model satisfactorily fitted the experimental data. It was observed that the rate of decomposition of DEP with the O(3)/H(2)O(2) and O(3)/AC systems is faster than that with only O(3). The technologies based on AOPs (UV/H(2)O(2), O(3)/H(2)O(2), O(3)/AC) significantly improve the degradation of DEP compared to conventional technologies (O(3), UV). AC adsorption, UV/H(2)O(2), O(3)/H(2)O(2), and O(3)/AC showed a high yield to remove DEP; however, the disadvantage of AC adsorption is its much longer time to reach maximum removal. The best system to treat water (ultrapure and natural) polluted with DEP is the O(3)/AC one since it achieved the highest DEP degradation and TOC removal, as well as the lower water toxicity.

  7. Isotope and Patient Age Predict for PSA Spikes After Permanent Prostate Brachytherapy

    SciTech Connect

    Bostancic, Chelsea; Merrick, Gregory S. . E-mail: gmerrick@urologicresearchinstitute.org; Butler, Wayne M.; Wallner, Kent E.; Allen, Zachariah; Galbreath, Robert; Lief, Jonathan; Gutman, Sarah E.

    2007-08-01

    Purpose: To evaluate prostate-specific antigen (PSA) spikes after permanent prostate brachytherapy in low-risk patients. Methods and Materials: The study population consisted of 164 prostate cancer patients who were part of a prospective randomized trial comparing {sup 103}Pd and {sup 125}I for low-risk disease. Of the 164 patients, 61 (37.2%) received short-course androgen deprivation therapy. The median follow-up was 5.4 years. On average, 11.1 post-treatment PSA measurements were obtained per patient. Biochemical disease-free survival was defined as a PSA level of {<=}0.40 ng/mL after nadir. A PSA spike was defined as an increase of {>=}0.2 ng/mL, followed by a durable decline to prespike levels. Multiple parameters were evaluated as predictors for a PSA spike. Results: Of the 164 patients, 44 (26.9%) developed a PSA spike. Of the 46 hormone-naive {sup 125}I patients and 57 hormone-naive {sup 103}Pd patients, 21 (45.7%) and 8 (14.0%) developed a PSA spike. In the hormone-naive patients, the mean time between implantation and the spike was 22.6 months and 18.7 months for {sup 125}I and {sup 103}Pd, respectively. In patients receiving neoadjuvant androgen deprivation therapy, the incidence of spikes was comparable between isotopes ({sup 125}I 28.1% and {sup 103}Pd 20.7%). The incidence of spikes was substantially different in patients <65 years vs. {>=}65 years old (38.5% vs. 16.3%). On multivariate Cox regression analysis, patient age (p < 0.001) and isotope (p = 0.002) were significant predictors for spike. Conclusion: In low-risk prostate cancer, PSA spikes are most common in patients implanted with {sup 125}I and/or <65 years of age. Differences in isotope-related spikes are most pronounced in hormone-naive patients.

  8. Low prefrontal PSA-NCAM confers risk for alcoholism-related behavior.

    PubMed

    Barker, Jacqueline M; Torregrossa, Mary M; Taylor, Jane R

    2012-10-01

    The factors underlying vulnerability to alcoholism are largely unknown. We identified in rodents an innate endophenotype predicting individual risk for alcohol-related behaviors that was associated with decreased expression of the neuroplasticity-related polysialylated neural cell adhesion molecule (PSA-NCAM). Depletion of PSA-NCAM in the ventromedial prefrontal cortex was sufficient to render mice unable to extinguish alcohol seeking, indicating a causal role of naturally occurring variation. These data suggest a mechanism of aberrant prefrontal neuroplasticity that underlies enhanced propensity for inflexible addiction-related behavior.

  9. ADSORPTION OF SURFACTANT ON CLAYS

    EPA Science Inventory

    Surfactants used to enhance remediation of soils by soil washing are often lost in the process. Neither the amount nor the cause of this loss is known. It is assumed that clays present in the soil are responsible for the loss of the surfactant. In this papere, adsorption prope...

  10. Thermodynamic features of dioxins' adsorption.

    PubMed

    Prisciandaro, Marina; Piemonte, Vincenzo; di Celso, Giuseppe Mazziotti; Ronconi, Silvia; Capocelli, Mauro

    2017-02-15

    In this paper, the six more poisonous species among all congeners of dioxin group are taken into account, and the P-T diagram for each of them is developed. Starting from the knowledge of vapour tensions and thermodynamic parameters, the theoretical adsorption isotherms are calculated according to the Langmuir's model. In particular, the Langmuir isotherm parameters (K and wmax) have been validated through the estimation of the adsorption heat (ΔHads), which varies in the range 20-24kJ/mol, in agreement with literature values. This result will allow to put the thermodynamical basis for a rational design of different process units devoted to dioxins removal.

  11. Adsorptive desulfurization by activated alumina.

    PubMed

    Srivastav, Ankur; Srivastava, Vimal Chandra

    2009-10-30

    This study reports usage of commercial grade activated alumina (aluminum oxide) as adsorbent for the removal of sulfur from model oil (dibenthiophene (DBT) dissolved in n-hexane). Bulk density of alumina was found to be 1177.77 kg/m(3). The BET surface area of alumina was found to decrease from 143.6 to 66.4 m(2)/g after the loading of DBT at optimum conditions. The carbon-oxygen functional groups present on the surface of alumina were found to be effective in the adsorption of DBT onto alumina. Optimum adsorbent dose was found to be 20 g/l. The adsorption of DBT on alumina was found to be gradual process, and quasi-equilibrium reached in 24 h. Langmuir isotherm best represented the equilibrium adsorption data. The heat of adsorption and change in entropy for DBT adsorption onto alumina was found to be 19.5 kJ/mol and 139.2 kJ/mol K, respectively.

  12. Presence of PSA auto-antibodies in men with prostate abnormalities (prostate cancer/benign prostatic hyperplasia/prostatitis).

    PubMed

    Lokant, M T; Naz, R K

    2015-04-01

    Prostate-specific antigen (PSA), produced by the prostate, liquefies post-ejaculate semen. PSA is detected in semen and blood. Increased circulating PSA levels indicate prostate abnormality [prostate cancer (PC), benign prostatic hyperplasia (BPH), prostatitis (PTIS)], with variance among individuals. As the prostate has been proposed as an immune organ, we hypothesise that variation in PSA levels among men may be due to presence of auto-antibodies against PSA. Sera from healthy men (n = 28) and men having prostatitis (n = 25), BPH (n = 30) or PC (n = 29) were tested for PSA antibody presence using enzyme-linked immunosorbent assay (ELISA) values converted to standard deviation (SD) units, and Western blotting. Taking ≥2 SD units as cut-off for positive immunoreactivity, 0% of normal men, 0% with prostatitis, 33% with BPH and 3.45% with PC demonstrated PSA antibodies. One-way analysis of variance (anova) performed on the mean absorbance values and SD units of each group showed BPH as significantly different (P < 0.01) compared with PC and prostatitis. All others were nonsignificant (P < 0.05). Men (33%) with BPH had PSA antibodies by ELISA and Western blot. These discoveries may find clinical application in differential diagnosis among prostate abnormalities, especially differentiating BPH from prostate cancer and prostatitis.

  13. Magnetic carbon composites with a hierarchical structure for adsorption of tetracycline, prepared from sugarcane bagasse via hydrothermal carbonization coupled with simple heat treatment process.

    PubMed

    Rattanachueskul, Natthanan; Saning, Amonrada; Kaowphong, Sulawan; Chumha, Nawapong; Chuenchom, Laemthong

    2017-02-01

    Sugarcane bagasse, an agricultural waste, was successfully converted into novel magnetic carbon composites by low temperature hydrothermal carbonization at 230°C for 24h, followed by heat treatment at 400°C for only 1h in air. Effects of NaOH and iron loading on the chemical properties of the composites were studied. In addition, various techniques were employed to investigate the physicochemical properties of the composites. Adsorption kinetics and isotherms were investigated with tetracycline (TC) for the magnetic composites. The magnetic carbon composite exhibited 48.35mg/g maximum adsorption capacity and was highly stable chemically and mechanically, with also good magnetic properties. The adsorption of TC by the magnetic adsorbent was mainly attributed to H-bonds and π-π interactions. The results indicate that waste sugarcane bagasse from the sugar industries can be efficiently transformed to a magnetic adsorbent for TC removal via a facile environmentally friendly method.

  14. PSA-NCAM is up-regulated during optic nerve regeneration in lizard but not in goldfish.

    PubMed

    Harman, A M; Rodger, J; Ahmat, A; Thomas, C; Bartlett, C; Chen, P; Dunlop, S A; Beazley, L D

    2003-07-01

    The addition of polysialic acid (PSA) to neural cell adhesion molecule (NCAM) facilitates axon growth. Here we use Western blots and immunohistochemistry to examine expression of PSA-NCAM during optic nerve regeneration. In lizard, retinal ganglion cell axons become transiently PSA-NCAM positive. By contrast, goldfish RGC axons are PSA-NCAM negative both in normal animals and throughout regeneration with the exception of a PSA-NCAM-positive fascicle arising from newly generated RGCs. Transient sialylation of NCAM in lizard may assist regeneration in the nonpermissive reptilian visual pathway and facilitate the reestablishment of a crude topographic map; down-regulation in the long term may contribute to the breakdown in topography. The lack of sialylation in goldfish presumably reflects the permissive nature of the substrate allowing axon regeneration and the successful reestablishment of a topographic map.

  15. Phosphoryl functionalized mesoporous silica for uranium adsorption

    NASA Astrophysics Data System (ADS)

    Xue, Guo; Yurun, Feng; Li, Ma; Dezhi, Gao; Jie, Jing; Jincheng, Yu; Haibin, Sun; Hongyu, Gong; Yujun, Zhang

    2017-04-01

    Phosphoryl functionalized mesoporous silica (TBP-SBA-15) was synthesized by modified mesoporous silica with γ-amino propyl triethoxy silane and tributyl phosphate. The obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), small angle X-ray diffraction (SAXRD), thermo-gravimetric/differential thermalanalyzer (TG/DTA), N2 adsorption-desorption (BET) and Fourier transform infrared spectroscopy (FT-IR) techniques. Results showed that TBP-SBA-15 had large surface areas with ordered channel structure. Moreover, the effects of adsorption time, sorbent dose, solution pH, initial uranium concentration and temperature on the uranium adsorption behaviors were investigated. TBP-SBA-15 showed a high uranium adsorption capacity in a broad range of pH values. The U(VI) adsorption rate of TBP-SBA-15 was fast and nearly achieved completion in 10 min with the sorbent dose of 1 g/L. The U(VI) adsorption of TBP-SBA-15 followed the pseudo-second-order kinetic model and Freundlich isotherm model, indicating that the process was belonged to chemical adsorption. Furthermore, the thermodynamic parameters (ΔG0, ΔH0 and ΔS0) confirmed that the adsorption process was endothermic and spontaneous.

  16. Adsorption of water vapor by poly(styrenesulfonic acid), sodium salt: isothermal and isobaric adsorption equilibria.

    PubMed

    Toribio, F; Bellat, J P; Nguyen, P H; Dupont, M

    2004-12-15

    Air conditioning and dehumidifying systems based on sorption on solids are of great interest, especially in humid climates, because they allow reduction of thermal loads and use of chlorofluorocarbons. Previous studies have shown that hydrophilic polymers such as sulfonic polymers can have very high performance in water adsorption from air. The aim of this study was to characterize the water vapor adsorption properties of fully sulfonated and monosulfonated poly(styrenesulfonic acid), sodium salt, and to elucidate the mechanism of adsorption on these materials. Adsorption isotherms have been determined by TGA between 298 and 317 K for pressures ranging from 0.1 to 45 hPa. They have type II of the IUPAC classification and a small hysteresis loop between adsorption and desorption processes was observed only for the monosulfonated sample. Water content is up to 80% weight at 80% relative humidity. Adsorption isotherms have been well fitted with the FHH model. Adsorption-desorption isobars have been determined by TGA under 37 hPa in the temperature range 298-373 K. They show that these polymers can be completely regenerated by heating at 313 K under humidified air. No degradation of the adsorption properties has been observed after several regenerations. Adsorption enthalpies and entropies have been deduced from the Clapeyron equation and from DSC measurements. A good agreement was found. A mechanism of adsorption is proposed considering two kinds of adsorbate: bounded water in electrostatic interaction with functional groups and free water resulting from condensation.

  17. Diagnostic ability of %p2PSA and prostate health index for aggressive prostate cancer: a meta-analysis

    PubMed Central

    Wang, Wenying; Wang, Meilin; Wang, Li; Adams, Tamara S.; Tian, Ye; Xu, Jianfeng

    2014-01-01

    The role of [-2]proPSA (p2PSA) based diagnostic tests for the detection of aggressive prostate cancer (PCa) has not been fully evaluated. We conducted a meta-analysis to evaluate the diagnostic performance of p2PSA/free PSA (%p2PSA) and prostate health index (Phi) tests for PCa and to evaluate their ability in discriminating between aggressive and non-aggressive PCa. A total of 16 articles were included in this meta-analysis. For the detection of PCa, the pooled sensitivity, specificity, and AUC were 0.86 (95% CI, 0.84–0.87), 0.40 (95% CI, 0.39–042) and 0.72 (95% CI, 0.67–0.77) for %p2PSA respectively, and were 0.85 (95% CI, 0.83–0.86), 0.45 (95% CI, 0.44–0.47) and 0.70 (95% CI = 0.65–0.74) for Phi, respectively. In addition, the sensitivity for discriminating PCa between higher Gleason score (≥7) and lower Gleason score (<7) was 0.96 (95% CI, 0.93–0.98) and 0.90 (95% CI, 0.87–0.92) for %p2PSA and Phi respectively, and the specificity was low, only 0.09 (95% CI, 0.06–0.12) and 0.17 (95% CI, 0.14–0.19) for %p2PSA and Phi, respectively. Phi and %p2PSA have a high diagnostic accuracy rates and can be used in PCa diagnosis. Phi and %p2PSA may be useful as tumor markers in predicating patients harboring more aggressive disease and guiding biopsy decisions. PMID:24852453

  18. Student-Designed Public Service Announcement (PSA) Videos to Enhance Motivation and Engagement

    ERIC Educational Resources Information Center

    Abrams, Kenneth

    2012-01-01

    Educators often focus on enhancing student motivation and engagement. This article describes an activity with these aims, in which undergraduates (a) learn about theories and research on means of persuasion and (b) in small groups design and record a public service announcement (PSA) video, write a brief paper that outlines the theories used to…

  19. PSA Velocity Does Not Improve Prostate Cancer Detection | Division of Cancer Prevention

    Cancer.gov

    A rapid increase in prostate-specific antigen (PSA) levels is not grounds for automatically recommending a prostate biopsy, according to a study published online February 24 in the Journal of the National Cancer Institute. |

  20. A Microfluidic Love-Wave Biosensing Device for PSA Detection Based on an Aptamer Beacon Probe.

    PubMed

    Zhang, Feng; Li, Shuangming; Cao, Kang; Wang, Pengjuan; Su, Yan; Zhu, Xinhua; Wan, Ying

    2015-06-11

    A label-free and selective aptamer beacon-based Love-wave biosensing device was developed for prostate specific antigen (PSA) detection. The device consists of the following parts: LiTaO3 substrate with SiO2 film as wave guide layer, two set of inter-digital transducers (IDT), gold film for immobilization of the biorecongniton layer and a polydimethylsiloxane (PDMS) microfluidic channels. DNA aptamer, or "artificial antibody", was used as the specific biorecognition probe for PSA capture. Some nucleotides were added to the 3'-end of the aptamer to form a duplex with the 3'-end, turning the aptamer into an aptamer-beacon. Taking advantage of the selective target-induced assembly changes arising from the "aptamer beacon", highly selective and specific detection of PSA was achieved. Furthermore, PDMS microfluidic channels were designed and fabricated to realize automated quantitative sample injection. After optimization of the experimental conditions, the established device showed good performance for PSA detection between 10 ng/mL to 1 μg/mL, with a detection limit of 10 ng/mL. The proposed sensor might be a promising alternative for point of care diagnostics.

  1. Quantifying the role of PSA screening in the US prostate cancer mortality decline

    PubMed Central

    Tsodikov, Alex; Mariotto, Angela; Szabo, Aniko; Falcon, Seth; Wegelin, Jake; diTommaso, Dante; Karnofski, Kent; Gulati, Roman; Penson, David F.; Feuer, Eric

    2010-01-01

    Objective To quantify the plausible contribution of prostate-specific antigen (PSA) screening to the nearly 30% decline in the US prostate cancer mortality rate observed during the 1990s. Methods Two mathematical modeling teams of the US National Cancer Institute’s Cancer Intervention and Surveillance Modeling Network independently projected disease mortality in the absence and presence of PSA screening. Both teams relied on Surveillance, Epidemiology, and End Results (SEER) registry data for disease incidence, used common estimates of PSA screening rates, and assumed that screening, by shifting disease from distant to local-regional clinical stage, confers a corresponding improvement in disease-specific survival. Results The teams projected similar mortality increases in the absence of screening and decreases in the presence of screening after 1985. By 2000, the models projected that 45% (Fred Hutchinson Cancer Research Center) to 70% (University of Michigan) of the observed decline in prostate cancer mortality could be plausibly attributed to the stage shift induced by screening. Conclusions PSA screening may account for much, but not all, of the observed drop in prostate cancer mortality. Other factors, such as changing treatment practices, may also have played a role in improving prostate cancer outcomes. PMID:18027095

  2. Infographic: Benefits and Harms of PSA Screening for Prostate Cancer | Division of Cancer Prevention

    Cancer.gov

    As more has been learned about the benefits and harms of prostate-specific antigen (PSA) screening, organizations have begun to recommend against routine screening. Screening is a personal decision that, according to most experts, a man should make in consultation with his doctor, after he has been informed in detail about the potential benefits and harms. |

  3. [Validity of PSA density of the transition zone in the diagnosis of prostate cancer].

    PubMed

    Anastasi, G; Magno, C; Carmignani, A; Inferrera, A; Petrelli, A; Broccio, G

    2000-12-01

    One hundred four patients (mean age 70.6 years) with prostatic specific antigen (PSA) values between 4 and 10 ng/ml (average 7.9 ng/ml), and with no suspects for neoplasia by digital rectal examination (DRE) and transrectal ultrasound (TRUS) were studied. In all patients PSA density for the entire prostate (PSAD) and PSA density for the transition zone (PSAT) were calculated. TRUS was performed using a 5 MHz probe. Prostate and transition zone volumes were obtained by ellipsoid formula. Aim of the study was to evaluate the PSAT predictivity for prostate cancer compared to the PSAD. Sixteen out of 104 patients (15.4%) had histologically confirmed prostate cancer, and 88 (84.6%) had benign prostatic hyperplasia. When cut-off for PSAD was 0.15 ng/ml/cc, specificity and sensitivity were respectively 75% and 68% with positive and negative predictive values of 54% and 17%; when cut-off for PSAT was 0.34% ng/ml/cc, sensitivity and specificity were respectively 100% and 68% with positive and negative predictive values of 60% and 18%. Our results, according to the literature data, suggest that PSAT seems to have a higher predictivity for prostate cancer than PSAD, providing an optimization for the employ of prostatic biopsy, especially for those patients with PSA values between 4 and 10 ng/ml.

  4. Proteomics of Peripheral Leukocytes in Patients with Elevated Serum Levels of PSA

    DTIC Science & Technology

    2011-09-01

    3 INTRODUCTION: This research has the long-term goal of developing a test that will discriminate between prostate cancer ( PrCA ) and benign...observed to have an elevated serum level of PSA, in order to distinguish among CP, BPH and PrCA . To achieve these objectives, we proposed to employ mass

  5. The dendritic spines of interneurons are dynamic structures influenced by PSA-NCAM expression.

    PubMed

    Guirado, Ramon; Perez-Rando, Marta; Sanchez-Matarredona, David; Castillo-Gómez, Esther; Liberia, Teresa; Rovira-Esteban, Laura; Varea, Emilio; Crespo, Carlos; Blasco-Ibáñez, José Miguel; Nacher, Juan

    2014-11-01

    Excitatory neurons undergo dendritic spine remodeling in response to different stimuli. However, there is scarce information about this type of plasticity in interneurons. The polysialylated form of the neural cell adhesion molecule (PSA-NCAM) is a good candidate to mediate this plasticity as it participates in neuronal remodeling and is expressed by some mature cortical interneurons, which have reduced dendritic arborization, spine density, and synaptic input. To study the connectivity of the dendritic spines of interneurons and the influence of PSA-NCAM on their dynamics, we have analyzed these structures in a subpopulation of fluorescent spiny interneurons in the hippocampus of glutamic acid decarboxylase-enhanced green fluorescent protein transgenic mice. Our results show that these spines receive excitatory synapses. The depletion of PSA in vivo using the enzyme Endo-Neuraminidase-N (Endo-N) increases spine density when analyzed 2 days after, but decreases it 7 days after. The dendritic spine turnover was also analyzed in real time using organotypic hippocampal cultures: 24 h after the addition of EndoN, we observed an increase in the apparition rate of spines. These results indicate that dendritic spines are important structures in the control of the synaptic input of hippocampal interneurons and suggest that PSA-NCAM is relevant in the regulation of their morphology and connectivity.

  6. 5-Year Downstream Outcomes Following Prostate-Specific Antigen (PSA) Screening in Older Men

    PubMed Central

    Walter, Louise C.; Fung, Kathy Z.; Kirby, Katharine A.; Shi, Ying; Espaldon, Roxanne; O'Brien, Sarah; Freedland, Stephen J.; Powell, Adam A.; Hoffman, Richard M.

    2013-01-01

    Background Despite ongoing controversies surrounding PSA screening, large numbers of men age 65+ undergo screening. However, there are few data quantifying the chain of events following screening in clinical practice to better inform decisions. The objective of this study is to quantify 5-year downstream outcomes following a PSA screening result > 4 ng/ml in older men. Methods Longitudinal cohort study of 295,645 men age 65+ who underwent PSA screening in the VA healthcare system in 2003 and were followed for 5 years using national VA and Medicare data. Among men whose index screening PSA was > 4 ng/ml we determined the number who underwent biopsy, were diagnosed with prostate cancer, were treated and survived 5-years, according to baseline characteristics. Biopsy and treatment complications were also assessed. Results 25,208 (8.5%) men had an index PSA > 4 ng/ml. During 5-year follow-up, 8,313 (33%) men underwent at least one biopsy, 5,220 (63%) of men biopsied were diagnosed with prostate cancer of whom 4,284 (82%) were treated. Receipt of biopsy decreased with advancing age and worsening comorbidity (P<0.001), whereas the percentage treated for biopsy-detected cancer exceeded 75% even among men age 85+, those with Charlson score 3+, and those with low-risk cancer. Among men with biopsy-detected cancer, the risk of dying of non-prostate cancer causes increased with advancing age and comorbidity (P<0.001). 468 (6%) of men had 7-day biopsy complications. Treatment complications included 584 (14%) men with new incontinence and 588 (14%) men with new erectile dysfunction. Conclusions Receipt of biopsy is low in older men with abnormal screening PSA and decreases with advancing age and comorbidity. However, once biopsy detects cancer most men undergo immediate treatment regardless of advancing age, comorbidity, or low-risk cancer. Understanding downstream outcomes in clinical practice should better inform individualized decisions among older men considering PSA

  7. Hydrogen adsorption on functionalized nanoporous activated carbons.

    PubMed

    Zhao, X B; Xiao, B; Fletcher, A J; Thomas, K M

    2005-05-12

    There is considerable interest in hydrogen adsorption on carbon nanotubes and porous carbons as a method of storage for transport and related energy applications. This investigation has involved a systematic investigation of the role of functional groups and porous structure characteristics in determining the hydrogen adsorption characteristics of porous carbons. Suites of carbons were prepared with a wide range of nitrogen and oxygen contents and types of functional groups to investigate their effect on hydrogen adsorption. The porous structures of the carbons were characterized by nitrogen (77 K) and carbon dioxide (273 K) adsorption methods. Hydrogen adsorption isotherms were studied at 77 K and pressure up to 100 kPa. All the isotherms were Type I in the IUPAC classification scheme. Hydrogen isobars indicated that the adsorption of hydrogen is very temperature dependent with little or no hydrogen adsorption above 195 K. The isosteric enthalpies of adsorption at zero surface coverage were obtained using a virial equation, while the values at various surface coverages were obtained from the van't Hoff isochore. The values were in the range 3.9-5.2 kJ mol(-1) for the carbons studied. The thermodynamics of the adsorption process are discussed in relation to temperature limitations for hydrogen storage applications. The maximum amounts of hydrogen adsorbed correlated with the micropore volume obtained from extrapolation of the Dubinin-Radushkevich equation for carbon dioxide adsorption. Functional groups have a small detrimental effect on hydrogen adsorption, and this is related to decreased adsorbate-adsorbent and increased adsorbate-adsorbate interactions.

  8. Proteomic analysis of patient tissue reveals PSA protein in the stroma of benign prostatic hyperplasia

    PubMed Central

    O’Malley, Katherine J.; Eisermann, Kurtis; Pascal, Laura E.; Parwani, Anil V.; Majima, Tsuyoshi; Graham, Lara; Hrebinko, Katherine; Acquafondata, Marie; Stewart, Nicolas A.; Nelson, Joel B.; Yoshimura, Naoki; Wang, Zhou

    2014-01-01

    BACKGROUND Benign prostatic hyperplasia (BPH) is an age-related disease frequently associated with lower urinary tract symptoms (LUTS) that involves hyperplasia of both epithelial and stromal cells. Stromal fibrosis is a distinctive feature of BPH, but the exact mechanisms underlying this phenomenon are poorly understood. METHODS In the current study, proteomics analyses were utilized to identify proteins altered in the BPH stromal compartment from patients with symptomatic BPH. Stromal cells were isolated from histological nodules of BPH by laser capture microdissection (LCM) and subjected to liquid chromatography/mass spectrometry. RESULTS Proteins identified included several stromal-specific proteins involved in extracellular matrix remodeling, focal adhesion and cellular junctions. Additionally, the proteomics array identified the presence of luminal epithelial secretory protein PSA. Immunostaining, ELISA, and in situ hybridization analyses of BPH tissues verified the presence of PSA protein but absence of PSA mRNA in the stromal compartment. E-cadherin was down-regulated in BPH epithelial cells compared to normal adjacent tissues, suggesting that alteration of cellular junctions could contribute to the presence of luminal epithelial secreted proteins PSA and KLK2 in the stromal compartment. CONCLUSIONS The above findings suggest that the presence of secreted proteins PSA and KLK2 from prostate luminal epithelial cells in BPH stroma is a hallmark of BPH nodules which could in part be due to alterations in cellular junction proteins and/or increased epithelial barrier permeability. Elucidating the cause and consequence of these secreted proteins in the stromal compartment of BPH may lead to new understanding of BPH pathogenesis as well as approaches to prevent and/or treat this common disease. PMID:24711254

  9. Kinetic and thermodynamic studies of sulforaphane adsorption on macroporous resin.

    PubMed

    Yuanfeng, Wu; Lei, Zhang; Jianwei, Mao; Shiwang, Liu; Jun, Huang; Yuru, You; Lehe, Mei

    2016-08-15

    The adsorption equilibrium, kinetic and thermodynamic of sulforaphane (SF) adsorption onto macroporous resin in aqueous phase were studied. The SP850 resin was screened as the appropriate resin for SF purification. From the equilibrium studies, the Redlich-Peterson model was found to be the best for description of the adsorption behavior of SF onto SP850 resin, followed by the Freundlich model and the Langmuir model. Batch equilibrium experiments demonstrated that, in the examined temperature range, the equilibrium adsorption capacity of SP850 resin decreased with increasing adsorption temperature. Thermodynamics studies indicated that the adsorption of SF was a physical, exothermic, and spontaneous process. The adsorption kinetics revealed that the pseudo-second-order kinetic model was suitable to characterize the kinetics of adsorption of SF onto SP850. Finally, the intra-particle diffusion model demonstrated that SF diffused quickly into macropores, and that diffusion slowed down in the meso- and micropores.

  10. Adsorption ability comparison of plasma proteins on amorphous carbon surface

    NASA Astrophysics Data System (ADS)

    Takeda, Aoi; Akasaka, Hiroki; Ohshio, Shigeo; Toda, Ikumi; Nakano, Masayuki; Saitoh, Hidetoshi

    2012-11-01

    To understand why amorphous carbon (a-C:H) film shows antithrombogenicity, an adsorption ability of plasma proteins on a-C:H surface was investigated. Protein adsorption is the initial process of clot formation. The protein adsorption ability on a-C:H film surface was compared by the detection using the surface plasmon resonance (SPR) phenomenon to estimate the protein adsorption. The protein adsorption abilities of a fibrinogen (Fib) and a human γ-globulin (HGG) were estimated by the SPR method using a multilayer structure of a-C:H/Au/Cr/glass. Although the adsorption of HGG for a-C:H was saturated at 32 μM in HGG concentration, the adsorption of Fib was not saturated under the detection limit of this method. These results indicated that the adsorption ability to the a-C:H film surface of Fib was higher than HGG.

  11. A comparative study on the properties, mechanisms and process designs for the adsorption of non-ionic or anionic dyes onto cationic-polymer/bentonite.

    PubMed

    Li, Qian; Yue, Qin-Yan; Sun, Hong-Jian; Su, Yuan; Gao, Bao-Yu

    2010-07-01

    The adsorption properties and mechanisms of a cationic-polymer/bentonite complex (EPI-DMA/bentonite), prepared from polyepicholorohydrin-dimethylamine and bentonite, for non-ionic dyes (Disperse Blue SBL and Vat Scarlet R) and anionic dyes (Reactive Violet K-3R and Acid Dark Blue 2G) were investigated in this study. The solution pH, presence of salt and surfactant can significantly affect the dye removal efficiency. The equilibrium data were analyzed using the Langmuir and Freundlich models. The Langmuir model is the most suitable to describe non-ionic dye adsorption, but for anionic dyes the Freundlich model is best. The kinetic data for the adsorption of different dyes were analyzed using pseudo first- and second-order equations, and the experimental data conformed to the pseudo second-order kinetic model better. The possibility of intraparticle diffusion was also examined by using the intraparticle diffusion equation. The single-stage batch adsorber design for the adsorption of both types of dyes onto EPI-DMA/bentonite was studied based on the Langmuir isotherm model for non-ionic dyes and the Freundlich isotherm model for anionic dyes. The results showed that the required amount of EPI-DMA/bentonite for 95% dye removal in 5 L dye solution with a concentration of 50 mg/L is 378.0 g for DB SBL, 126.5 g for VS R, 9.7 g for RV K-3R and 15.5 g for ADB 2G.

  12. The Low Molecular Weight Protein PsaI Stabilizes the Light-Harvesting Complex II Docking Site of Photosystem I.

    PubMed

    Plöchinger, Magdalena; Torabi, Salar; Rantala, Marjaana; Tikkanen, Mikko; Suorsa, Marjaana; Jensen, Poul-Erik; Aro, Eva Mari; Meurer, Jörg

    2016-09-01

    PsaI represents one of three low molecular weight peptides of PSI. Targeted inactivation of the plastid PsaI gene in Nicotiana tabacum has no measurable effect on photosynthetic electron transport around PSI or on accumulation of proteins involved in photosynthesis. Instead, the lack of PsaI destabilizes the association of PsaL and PsaH to PSI, both forming the light-harvesting complex (LHC)II docking site of PSI. These alterations at the LHCII binding site surprisingly did not prevent state transition but led to an increased incidence of PSI-LHCII complexes, coinciding with an elevated phosphorylation level of the LHCII under normal growth light conditions. Remarkably, LHCII was rapidly phosphorylated in ΔpsaI in darkness even after illumination with far-red light. We found that this dark phosphorylation also occurs in previously described mutants impaired in PSI function or state transition. A prompt shift of the plastoquinone (PQ) pool into a more reduced redox state in the dark caused an enhanced LHCII phosphorylation in ΔpsaI Since the redox status of the PQ pool is functionally connected to a series of physiological, biochemical, and gene expression reactions, we propose that the shift of mutant plants into state 2 in darkness represents a compensatory and/or protective metabolic mechanism. This involves an increased reduction and/or reduced oxidation of the PQ pool, presumably to sustain a balanced excitation of both photosystems upon the onset of light.

  13. Association of GPs’ risk attitudes, level of empathy, and burnout status with PSA testing in primary care

    PubMed Central

    Pedersen, Anette F; Carlsen, Anders H; Vedsted, Peter

    2015-01-01

    Background Rates of prostate specific antigen (PSA) test ordering vary among GPs. Aim To examine whether GPs’ risk attitude, level of empathy, and burnout status are associated with PSA testing. Design and setting Register and questionnaire study including 129 solo GPs (active in the Central Denmark Region) and 76 672 of their adult male patients with no history of or current prostate cancer diagnosis. Method PSA tests from 2012 were retrieved from a register and classified as incident (that is, the first PSA test within 24 months), repeated normal, or repeated raised tests. This was merged with information on GPs’ risk attitudes, empathy, and burnout status from a 2012 survey. Results Patients registered with a GP with a high score on anxiety caused by uncertainty (odds ratio [OR] 1.03, 95% confidence interval [CI] = 1.00 to 1.06, P = 0.025) or concern about bad outcomes (OR 1.04; 95% CI = 1.00 to 1.08, P = 0.034) were more likely to have an incident PSA test, whereas those registered with a GP with increased tolerance for ambiguity were less likely (OR 0.98, 95% CI = 0.96 to 1.00, P = 0.025). Patients registered with a GP reporting high tolerance for ambiguity (OR 0.96, 95% CI = 0.94 to 0.99, P = 0.009) or high propensity to risk-taking (OR 0.97, 95% CI = 0.93 to 1.00, P = 0.047) were less likely to have a repeated normal PSA test. Conclusion Various aspects of GPs’ risk-taking attitudes were associated with patients’ probability of having an incident and a repeated normal PSA test. The probability of having a repeated raised PSA test was not influenced by any of the psychological factors. Burnout and empathy were not associated with PSA testing. PMID:26541183

  14. First Prototype of a Web Map Interface for ESA's Planetary Science Archive (PSA)

    NASA Astrophysics Data System (ADS)

    Manaud, N.; Gonzalez, J.

    2014-04-01

    We present a first prototype of a Web Map Interface that will serve as a proof of concept and design for ESA's future fully web-based Planetary Science Archive (PSA) User Interface. The PSA is ESA's planetary science archiving authority and central repository for all scientific and engineering data returned by ESA's Solar System missions [1]. All data are compliant with NASA's Planetary Data System (PDS) Standards and are accessible through several interfaces [2]: in addition to serving all public data via FTP and the Planetary Data Access Protocol (PDAP), a Java-based User Interface provides advanced search, preview, download, notification and delivery-basket functionality. It allows the user to query and visualise instrument observations footprints using a map-based interface (currently only available for Mars Express HRSC and OMEGA instruments). During the last decade, the planetary mapping science community has increasingly been adopting Geographic Information System (GIS) tools and standards, originally developed for and used in Earth science. There is an ongoing effort to produce and share cartographic products through Open Geospatial Consortium (OGC) Web Services, or as standalone data sets, so that they can be readily used in existing GIS applications [3,4,5]. Previous studies conducted at ESAC [6,7] have helped identify the needs of Planetary GIS users, and define key areas of improvement for the future Web PSA User Interface. Its web map interface shall will provide access to the full geospatial content of the PSA, including (1) observation geometry footprints of all remote sensing instruments, and (2) all georeferenced cartographic products, such as HRSC map-projected data or OMEGA global maps from Mars Express. It shall aim to provide a rich user experience for search and visualisation of this content using modern and interactive web mapping technology. A comprehensive set of built-in context maps from external sources, such as MOLA topography, TES

  15. Adsorption Refrigeration System

    SciTech Connect

    Wang, Kai; Vineyard, Edward Allan

    2011-01-01

    Adsorption refrigeration is an environmentally friendly cooling technology which could be driven by recovered waste heat or low-grade heat such as solar energy. In comparison with absorption system, an adsorption system has no problems such as corrosion at high temperature and salt crystallization. In comparison with vapor compression refrigeration system, it has the advantages of simple control, no moving parts and less noise. This paper introduces the basic theory of adsorption cycle as well as the advanced adsorption cycles such as heat and mass recovery cycle, thermal wave cycle and convection thermal wave cycle. The types, characteristics, advantages and drawbacks of different adsorbents used in adsorption refrigeration systems are also summarized. This article will increase the awareness of this emerging cooling technology among the HVAC engineers and help them select appropriate adsorption systems in energy-efficient building design.

  16. A new polysialic acid production process based on dual-stage pH control and fed-batch fermentation for higher yield and resulting high molecular weight product.

    PubMed

    Zheng, Zhi-Yong; Wang, Shun-Zhi; Li, Guo-Shun; Zhan, Xiao-Bei; Lin, Chi-Chung; Wu, Jian-Rong; Zhu, Li

    2013-03-01

    To determine the factors influencing the resulting molecular weight of polysialic acid (PSA), batch fermentations by using Escherichia coli were conducted. It was found that temperature and pH were significant factors affecting the PSA production and its resulting molecular weight. When pH was set at 6.4, temperature of 37 °C was suitable for cell growth and PSA production while 33 °C facilitated production of higher molecular weight of PSA. pH 6.4 was favorable for PSA production while pH 7.4 was good for higher molecular weight of PSA at 37 °C. Intramolecular self-cleavage of PSA might lead to relatively low molecular weight under mild acidic condition. Our data suggest that the PSA molecular weight is significantly affected by the pH condition rather than the temperature. It is concluded that the resulting PSA molecular weight not only depends on fermentation conditions but also relates to cell growth rate and PSA production rate. Higher PSA molecular weight was made when its production rate was faster than degradation rate. A novel two-stage pH control fermentation process for production of high molecular weight PSA was developed. At the first stage, pH was set at 6.4 to encourage cell growth and PSA production, whereas pH was set at 7.4 at the second stage to promote the formation of higher molecular weight PSA. PSA yield up to 5.65 g/L and its resulting molecular weight of 260 kDa was attained, the highest level ever reported.

  17. Diagnostic value of microRNAs in prostate cancer patients with prostate specific antigen (PSA) levels between 2, and 10 ng/mL

    PubMed Central

    Akbayır, Serin; Muşlu, Necati; Erden, Sema; Bozlu, Murat

    2016-01-01

    Objective Prostate specific antigen (PSA), used for the early diagnosis of prostate cancer (PCa), is one of the best tumour markers known so far. However, in situations when PSA is between 2–10 ng/mL, which is named as grey zone, PSA falls short of distinguishing benign prostate diseases from PCa. On the other hand, it was demonstrated in many previous studies that microRNA (miRNA) could be a marker for cancer. Therefore, in this study, it was aimed to enhance the diagnostic power of PSA, especially with grey zone patients, by the use of miRNA. Material and Methods Ninety-four patients included in the study were divided into three groups as “control group” (n=44, PSA=2–10 ng/mL and benign), “PCa 1 group” (n=37, PSA=2–10 ng/mL), and “PCa 2 group” (n=13, PSA >10 ng/mL), according to their pathological results and PSA levels. Free PSA (fPSA) and total PSA (T-PSA) levels were measured with chemiluminometric sandwich immunoassay method. Expressions of miRNAs were analyzed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) method. The most appropriate specificity, sensitivity and prediction values were found by drawing the receiver operating characteristic (ROC) curves of total PSA, free/total PSA (f/T PSA) ratio, and miRNAs, and the diagnostic powers were compared with each other. Results Diagnostic powers of the f/T PSA ratio and miRNA were compared in PCa 1 and the control groups to determine the marker with higher area under the curve (AUC). It was shown that the diagnostic power of the combination of miR-16-5p and f/T PSA was higher than that obtained when they were used separately. Conclusion As a result, while making the the discrimination between benign and malignant prostate in patients with grey zone, it was determined that the combination of miR-16-5p and f/T PSA was more valuable than T-PSA or f/T PSA alone. It was thought that diagnostic role of miRNAs in the early diagnosis of the different stages of PCa needed to

  18. Adsorption kinetics of laterally and polarly flagellated Vibrio.

    PubMed Central

    Belas, M R; Colwell, R R

    1982-01-01

    The adsorption of laterally and polarly flagellated bacteria to chitin was measured, and from the data obtained, a modified Langmuir adsorption isotherm was derived. Results indicated that the adsorption of laterally flagellated Vibrio parahaemolyticus follows the Langmuir adsorption isotherm, a type of adsorption referred to as surface saturation kinetics, when conditions are favorable for the production of lateral flagella. When conditions were not favorable for the production of lateral flagella, bacterial adsorption did not follow the Langmuir adsorption isotherm; instead, proportional adsorption kinetics were observed. The adsorption of some polarly flagellated bacteria exhibited surface saturation kinetics. However, the binding index (the product of the number of binding sites and bacterial affinity to the surface) of polarly flagellated bacteria differed significantly from that of laterally flagellated bacteria, suggesting that polarly flagellated bacteria adsorb to chitin by a different mechanism from that used by the laterally flagellated bacteria. From the results of dual-label adsorption competition experiments, in which polarly flagellated V. cholerae competed with increasing concentrations of laterally flagellated V. parahaemolyticus, it was observed that laterally flagellated bacteria inhibited the adsorption of polarly flagellated bacteria. In contrast, polarly flagellated bacteria enhanced the adsorption of V. cholerae. In competition experiments, where V. parahaemolyticus competed against increasing concentrations of other bacteria, polarly flagellated bacteria enhanced V. parahaemolyticus adsorption significantly, whereas laterally flagellated bacteria only slightly enhanced the process. The direct correlation observed between surface saturation kinetics, the production of lateral flagella, and the ability of laterally flagellated bacteria to inhibit the adsorption of polarly flagellated bacteria suggests that lateral flagella represent a

  19. Adsorption isotherm of non-azeotropic solution onto porous adsorbents

    NASA Astrophysics Data System (ADS)

    Bono, A.; Ramlan, N. A.; Anisuzzaman, S. M.; Chu, C. M.; Farm, Y. Y.

    2016-06-01

    Adsorption isotherm is essential component in the understanding of the adsorption process. Several methods of the measurements, analysis and interpretation of adsorption from solution have been reported in the literature. Most of the measurements of adsorption isotherm from solution were involved the measurement of excess isotherm conducted at low region of sorbates concentration. Direct interpretation of excess adsorption isotherm as adsorption isotherm is always been practice. Therefore, in this work a study on the measurement of the adsorption isotherm from solution of non-azeotropic organic solvent mixture onto porous adsorbents for whole range of liquid concentration was conducted. The study included the measurement of excess adsorption isotherm using conventional technique. Theoretical analysis and interpretation of adsorption isotherm from the excess isotherm were conducted using Pseudo Ideal Adsorption, Gibbs Dividing Plane Model and Langmuir-Fruendlich binary isotherm model. For organic solvents, acetone and propanol were chosen as the adsorbates due to the non-azeotropic properties in the mixture. Activated carbon and silicalite were chosen as adsorbents due to the different in their porosity such as macro porous and micro porous structure. The result of the study has revealed that the adsorption isotherm of non-azeotropic mixture onto activated carbon and silicalite can be interpreted as monolayer type of adsorption.

  20. The synthesis and characterization of monodispersed chitosan-coated Fe3O4 nanoparticles via a facile one-step solvothermal process for adsorption of bovine serum albumin.

    PubMed

    Shen, Mao; Yu, Yujing; Fan, Guodong; Chen, Guang; Jin, Ying Min; Tang, Wenyuan; Jia, Wenping

    2014-01-01

    Preparation of magnetic nanoparticles coated with chitosan (CS-coated Fe3O4 NPs) in one step by the solvothermal method in the presence of different amounts of added chitosan is reported here. The magnetic property of the obtained magnetic composite nanoparticles was confirmed by X-ray diffraction (XRD) and magnetic measurements (VSM). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) allowed the identification of spherical nanoparticles with about 150 nm in average diameter. Characterization of the products by Fourier transform infrared spectroscopy (FTIR) demonstrated that CS-coated Fe3O4 NPs were obtained. Chitosan content in the obtained nanocomposites was estimated by thermogravimetric analysis (TGA). The adsorption properties of the CS-coated Fe3O4 NPs for bovine serum albumin (BSA) were investigated under different concentrations of BSA. Compared with naked Fe3O4 nanoparticles, the CS-coated Fe3O4 NPs showed a higher BSA adsorption capacity (96.5 mg/g) and a fast adsorption rate (45 min) in aqueous solutions. This work demonstrates that the prepared magnetic nanoparticles have promising applications in enzyme and protein immobilization.

  1. Removal of 2,4-D from aqueous solutions by adsorption processes using two biopolymers: chitin and chitosan and their optical properties

    NASA Astrophysics Data System (ADS)

    El Harmoudi, H.; El Gaini, L.; Daoudi, E.; Rhazi, M.; Boughaleb, Y.; El Mhammedi, M. A.; Migalska-Zalas, A.; Bakasse, M.

    2014-07-01

    Chitin, extracted primarily from exoskeleton shellfish, is one of the most abundant biopolymer in the world. It is estimated to be produced annually almost as much as cellulose. The development of fishing activities in Morocco (coastline of 3500 km on both the Atlantic and the Mediterranean) induced an important fish industry waste. The aim of this work is to recover chitin, extracted from shellfish waste, and chitosan, produced by deacetylation of chitin, in the adsorption of organic pesticide 2,4-dichlorophenoxyacetate (2,4-D). The chitosan samples were prepared from chitin from crustacean shells. The chitin deacetylation was carried out in aqueous sodium hydroxide. Characterization of chitin and chitosan was performed by infrared spectroscopy, nuclear magnetic resonance and theoretical calculation of UV-Vis spectra and optical parameters. Analysis of theoretical spectra shows a substantial sensitivity to the hydroxyl and amino groups. The presented hydroxyl group in chitin determines the conformation of the molecule and also the stereochemistry of chemical reactions and kinetics. The presence of functional groups causes the substantial changes of both absorption spectra as well as permanent dipole moment. The adsorption of 2,4-D by chitin and chitosan was performed at different pH values, the pesticide-adsorbent contact time and initial pesticide concentration. The adsorption is described by Langmuir-type isotherm and Freundlich-type isotherm. Recovery tests of 2,4-D confirm the initial interest in using chitin and chitosan as a depolluting agent.

  2. [Relationship between PTH and PSA values in patients with pathological finding of benign prostatic hyperplasia].

    PubMed

    Romeo, Salvatore; Napoli, Giancarlo; Melloni, Guglielmo; Dispensa, Nino; Melloni, Darwin

    2012-01-01

    The functional relationship between parathyroid glands and prostatic gland is commonly very well known. The aim of our study was to investigate the relationship between serum levels of PTH and serum levels of PSA in patients with pathological finding of BPH. According to 261 transrectal ultrasound-guided prostatic biopsies performed from March 2009 to March 2010, 75 patients, responding to our inclusion criteria, were selected. 26 patients (34.6%) ended the study. All patients with high serum levels of PSA (>4 ng/mL), with histological diagnosis of benign prostatic hyperplasia, underwent the assay of serum levels of PTH. We observed high levels of PTH (> 66 pg/mL) in 9 patients (35.2%).

  3. Non-granule PSA-NCAM immunoreactive neurons in the rat hippocampus.

    PubMed

    Nacher, Juan; Blasco-Ibáñez, José M; McEwen, Bruce S

    2002-03-15

    The polysialylated form of the neural cell adhesion molecule (PSA-NCAM) continues to be expressed in the adult hippocampus, mainly in a subset of neurons located in the innermost portion of the granule cell layer. PSA-NCAM immunoreactive neurons have also been described outside this layer in humans, where they are severely reduced in schizophrenic brains. Given this important clinical implication, we were interested in finding whether similar neurons existed in the adult rat hippocampus and to characterize their distribution, morphology and phenotype. PSA-NCAM immunocytochemistry reveals labeled neurons in the subiculum, fimbria, alveus, hilus, and stratum oriens, lucidum and radiatum of CA3 and CA1. They are mainly distributed in the ventral hippocampus, and have polygonal or fusiform somata with multipolar or bipolar morphology. These neurons show long straight dendrites, which reach several strata and even enter the fimbria and the alveus. These dendrites are often varicose, appear devoid of excrescences and apparently do not show spines. Most of these neurons display GABA immunoreactivity and further analysis has shown that a subpopulation expresses calretinin, but not somatostatin, neuropeptide Y, parvalbumin, calbindin or NADPH diaphorase. Our study demonstrates that there is an important subpopulation of PSA-NCAM immunoreactive neurons, many of which can be considered interneurons, outside the rat granule cell layer, probably homologous to those described in the human hippocampus. The presence of the polysialylated form of NCAM in these neurons could indicate that they are undergoing continuous remodeling during adulthood and may have an important role in hippocampal structural plasticity.

  4. Prostate Cancer Survivors with Rising PSA and Their Spouses: Treatment Decision Making and Quality of Life

    DTIC Science & Technology

    2009-12-31

    Center, Philadelphia. Patients will have been diagnosed with rising PSA but have no clinical evidence of cancer . Eligible patients and their spouse...From a psychological point of view, patients and their spouses/partners are forced to deal with a disease they believed they have overcome. For a... patients and their spouse/partners have to deal with the uncertainty of a cancer recurrence and cancer spread, and the possibility of death. Very

  5. A Diet, Physical Activity, and Meditation Intervention in Men With Rising Prostate-Specific Antigen (PSA)

    DTIC Science & Technology

    2006-05-01

    14. ABSTRACT: Following surgery or radiation of primary early-stage prostate cancer ( PrCA ), one in three patients will experience an elevation in...androgen ablation. We hypothesize that the host- PrCA balance in asymptomatic men with biochemically recurrent PrCA , as reflected by the PSA rise, is...Registry letters Reminder Call Script 4 Introduction: Prostate cancer ( PrCA ) is the most commonly occurring cancer, excluding skin

  6. Power-free chip enzyme immunoassay for detection of prostate specific antigen (PSA) in serum.

    PubMed

    Adel Ahmed, Heba; Azzazy, Hassan M E

    2013-11-15

    A power-free, portable "Chip EIA" was designed to render the popular Enzyme Linked Immunosorbent Assay (ELISA) more suitable for point-of-care testing. A number of microfluidic platforms have enabled miniaturization of the conventional microtitre plate ELISA, however, they require external pumping systems, valves, and electric power supply. The Chip EIA platform has eliminated the need for pumps and valves through utilizing a simple permanent magnet and magnetic nanoparticles. The magnetic nanoparticles act as solid support to capture the target and are then moved through chambers harboring different reagents necessary to perform a sandwich ELISA. The use of magnetic nanoparticles increases the volume-to-surface ratio reducing the assay time to 30 min. Changing the color of horseradish peroxidase (HRP) substrate to green indicates a positive result. In addition, a quantitative read-out was obtained through the use of cellphone camera imaging and analyzing the images using Matlab®. Cell phones, including smart ones, are readily available almost everywhere. The Chip EIA device was used to assay total prostate specific antigen (tPSA) in 19 serum samples. The PSA Chip EIA was tested for accuracy, precision, repeatability, and the results were correlated to the commercial Beckman Colter, Hybritech immunoassay® for determination of tPSA in serum samples with a Pearson correlation coefficient (R(2)=0.96). The lower detection limit of the PSA Chip EIA was 3.2 ng/mL. The assay has 88.9% recovery and good reproducibility (% CV of 6.5). We conclude that the developed Chip EIA can be used for detection of protein biomarkers in biological specimens.

  7. Multiple external hazards compound level 3 PSA methods research of nuclear power plant

    NASA Astrophysics Data System (ADS)

    Wang, Handing; Liang, Xiaoyu; Zhang, Xiaoming; Yang, Jianfeng; Liu, Weidong; Lei, Dina

    2017-01-01

    2011 Fukushima nuclear power plant severe accident was caused by both earthquake and tsunami, which results in large amount of radioactive nuclides release. That accident has caused the radioactive contamination on the surrounding environment. Although this accident probability is extremely small, once such an accident happens that is likely to release a lot of radioactive materials into the environment, and cause radiation contamination. Therefore, studying accidents consequences is important and essential to improve nuclear power plant design and management. Level 3 PSA methods of nuclear power plant can be used to analyze radiological consequences, and quantify risk to the public health effects around nuclear power plants. Based on multiple external hazards compound level 3 PSA methods studies of nuclear power plant, and the description of the multiple external hazards compound level 3 PSA technology roadmap and important technical elements, as well as taking a coastal nuclear power plant as the reference site, we analyzed the impact of off-site consequences of nuclear power plant severe accidents caused by multiple external hazards. At last we discussed the impact of off-site consequences probabilistic risk studies and its applications under multiple external hazards compound conditions, and explained feasibility and reasonableness of emergency plans implementation.

  8. PSA bounces after neoadjuvant androgen deprivation and external beam radiation: Impact on definitions of failure

    SciTech Connect

    Zietman, Anthony L. . E-mail: azietman@partners.org; Christodouleas, John P.; Shipley, William U.

    2005-07-01

    Purpose: To determine the characteristics of prostate specific antigen (PSA) bounces after external beam radiation therapy (EBRT) with neoadjuvant androgen deprivation and their impact on definitions of biochemical failure. Methods and Materials: Characteristics of bounce were calculated for all patients treated by EBRT with neoadjuvant androgen deprivation at our institution between 1992 and 1998 (preexclusion analysis). Calculations were repeated for the subgroup that satisfied additional inclusion/exclusion criteria (postexclusion analysis). The percentage of bounces scoring as false positives according to the ASTRO definition of biochemical failure was compared with those for three alternative definitions (Vancouver, Nadir-plus-two, and Nadir-plus-three) using McNemar's tests. Results: Thirty-nine percent (preexclusion cohort) and 56% (postexclusion cohort) of patients demonstrated a PSA bounce. Twenty percent (preexclusion analysis) and 25% (postexclusion analysis) of these bounces scored as biochemical failure according to the ASTRO definition. The Nadir-plus-three definition scored the smallest percentage of bounces as failure, but the difference between this definition and the ASTRO definition reached statistical significance in neither preexclusion nor postexclusion analyses (p {>=} 0.070). Conclusions: A substantial proportion of patients treated by EBRT with neoadjuvant deprivation experienced a PSA bounce. A large percentage of these bounces scored as biochemical failure according to the ASTRO definition. The Nadir-plus-three definition is less vulnerable to this bias.

  9. Prostate-Specific Antigen Working Group’s Guidelines on PSA Doubling Time

    PubMed Central

    Arlen, Philip M.; Bianco, Fernando; Dahut, William L.; D’Amico, Anthony; Figg, William D.; Freedland, Stephen J.; Gulley, James L.; Kantoff, Philip W.; Kattan, Michael W.; Lee, Andrew; Regan, Meredith M.; Sartor, Oliver

    2009-01-01

    Purpose Prostate-specific antigen is a glycoprotein found almost exclusively in normal and neoplastic prostate cells. PSA doubling time, or the change in PSA level over time, has emerged as a useful predictive marker for assessing disease outcome in patients with prostate cancer. It is important to agree on definitions and values for the calculation of PSADT and to develop a common approach to outcome analysis and reporting. Methods In September 2006 a conference was held at the National Cancer Institute in Bethesda, Maryland to define these parameters and develop guidelines for their use. Results The PSA Working Group defined the following criteria regarding PSADT: (1) calculation of PSADT, (2) evidence to support PSADT as a predictive factor in the setting of biochemical recurrence, and (3) use of PSADT as a stratification factor in clinical trials. Conclusions We propose that investigators calculate PSADT prior to enrolling patients on clinical studies and calculate it as an additional measurement of therapeutic activity. We believe we have developed practical guidelines for the calculation of PSADT and its use as a measurement of prognosis and outcome. Furthermore, the use of common standards for PSADT in clinical trials is important as we determine which treatments should progress to randomized trials in which “hard” end points such as survival will be employed. PMID:18423743

  10. Characterization of the Glycosylation Site of Human PSA Prompted by Missense Mutation using LC-MS/MS.

    PubMed

    Song, Ehwang; Hu, Yunli; Hussein, Ahmed; Yu, Chuan-Yih; Tang, Haixu; Mechref, Yehia

    2015-07-02

    Prostate specific antigen (PSA) is currently used as a diagnostic biomarker for prostate cancer. It is a glycoprotein possessing a single glycosylation site at N69. During our previous study of PSA N69 glycosylation, additional glycopeptides were observed in the PSA sample that were not previously reported and did not match glycopeptides of impure glycoproteins existing in the sample. This extra glycosylation site of PSA is associated with a mutation in KLK3 genes. Among single nucleotide polymorphisms (SNPs) of KLKs families, the rs61752561 in KLK3 genes is an unusual missense mutation resulting in the conversion of D102 to N in PSA amino acid sequence. Accordingly, a new N-linked glycosylation site is created with an N102MS motif. Here we report the first qualitative and quantitative glycoproteomic study of PSA N102 glycosylation site by LC-MS/MS. We successfully applied tandem MS to verify the amino acid sequence possessing N102 glycosylation site and associated glycoforms of PSA samples acquired from different suppliers. Among the three PSA samples, HexNAc2Hex5 was the predominant glycoform at N102, while HexNAc4Hex5Fuc1NeuAc1 or HexNAc4Hex5Fuc1NeuAc2 was the primary glycoforms at N69. D102 is the first amino acid of "kallikrein loop", which is close to a zinc-binding site and catalytic triad. The different glycosylation of N102 relative to N69 might be influenced by the close vicinity of N102 to these functional sites and steric hindrance.

  11. Recombinant Forms of Leishmania amazonensis Excreted/Secreted Promastigote Surface Antigen (PSA) Induce Protective Immune Responses in Dogs

    PubMed Central

    Petitdidier, Elodie; Pagniez, Julie; Papierok, Gérard; Vincendeau, Philippe; Lemesre, Jean-Loup; Bras-Gonçalves, Rachel

    2016-01-01

    Preventive vaccination is a highly promising strategy for interrupting leishmaniasis transmission that can, additionally, contribute to elimination. A vaccine formulation based on naturally excreted secreted (ES) antigens was prepared from L. infantum promastigote culture supernatant. This vaccine achieved successful results in Phase III trials and was licensed and marketed as CaniLeish. We recently showed that newly identified ES promastigote surface antigen (PSA), from both viable promastigotes and axenically-grown amastigotes, represented the major constituent and the highly immunogenic antigen of L. infantum and L. amazonensis ES products. We report here that three immunizations with either the recombinant ES LaPSA-38S (rPSA) or its carboxy terminal part LaPSA-12S (Cter-rPSA), combined with QA-21 as adjuvant, confer high levels of protection in naive L. infantum-infected Beagle dogs, as checked by bone marrow parasite absence in respectively 78.8% and 80% of vaccinated dogs at 6 months post-challenge. The parasite burden in infected vaccinated dogs was significantly reduced compared to placebo group, as measured by q-PCR. Moreover, our results reveal humoral and cellular immune response clear-cut differences between vaccinated and control dogs. An early increase in specific IgG2 antibodies was observed in rPSA/QA-21- and Cter-rPSA/QA-21-immunized dogs only. They were found functionally active in vitro and were highly correlated with vaccine protection. In vaccinated protected dogs, IFN-γ and NO productions, as well as anti-leishmanial macrophage activity, were increased. These data strongly suggest that ES PSA or its carboxy-terminal part, in recombinant forms, induce protection in a canine model of zoonotic visceral leishmaniasis by inducing a Th1-dominant immune response and an appropriate specific antibody response. These data suggest that they could be considered as important active components in vaccine candidates. PMID:27223609

  12. The influence of stress, depression, and anxiety on PSA screening rates in a nationally-representative sample

    PubMed Central

    Kotwal, Ashwin A.; Schumm, Phil; Mohile, Supriya G.; Dale, William

    2012-01-01

    Background Prostate-specific antigen (PSA) testing for prostate cancer (PCa) is controversial, with concerning rates of both over- and under-screening. The reasons for the observed rates of screening are unknown, and few studies have examined the relationship of psychological health to PSA screening rates. Understanding this relationship can help guide interventions to improve informed-decision making (IDM) for screening. Methods A nationally-representative sample of men 57–85 years old without PCa (N=1,169) from the National Social life, Health and Aging Project (NSHAP) was analyzed. The independent relationship of validated psychological health scales measuring stress, anxiety, and depression to PSA testing rates was assessed using multvariable logistic regression analyses. Results PSA screening rates were significantly lower for men with higher perceived stress (OR=0.76, p=0.006), but not for higher depressive symptoms (OR=0.89, p=0.22) when accounting for stress. Anxiety influences PSA screening through an interaction with number of doctor visits (p=0.02). Among the men who visited the doctor 1 time, those with higher anxiety were less likely to be screened (OR=0.65, p=0.04). Conversely, among those who visited the doctor 10+ times with higher anxiety were more likely to be screened (OR=1.71, p=0.04). Conclusions Perceived stress significantly lowers PSA screening likelihood, and it appears to partly mediate the negative relationship of depression with screening likelihood. Anxiety affects PSA screening rates differently for men with different numbers of doctor visits. Interventions to influence PSA screening rates should recognize the role of the patients’ psychological state to improve their likelihood of making informed decisions and improve screening appropriateness. PMID:22955835

  13. Adsorption of selected volatile organic vapors on multiwall carbon nanotubes.

    PubMed

    Shih, Yang-hsin; Li, Mei-syue

    2008-06-15

    Carbon nanotubes are expected to play an important role in sensing, pollution treatment and separation techniques. This study examines the adsorption behaviors of volatile organic compounds (VOCs), n-hexane, benzene, trichloroethylene and acetone on two multiwall carbon nanotubes (MWCNTs), CNT1 and CNT2. Among these VOCs, acetone exhibits the highest adsorption capacity. The highest adsorption enthalpies and desorption energies of acetone were also observed. The strong chemical interactions between acetone and both MWCNTs may be the result from chemisorption on the topological defects. The adsorption heats of trichloroethylene, benzene, and n-hexane are indicative of physisorption on the surfaces of both MWCNTs. CNT2 presents a higher adsorption capacity than CNT1 due to the existence of an exterior amorphous carbon layer on CNT2. The amorphous carbon enhances the adsorption capacity of organic chemicals on carbon nanotubes. The morphological and structure order of carbon nanotubes are the primary affects on the adsorption process of organic chemicals.

  14. A Simple Adsorption Experiment

    ERIC Educational Resources Information Center

    Guirado, Gonzalo; Ayllon, Jose A.

    2011-01-01

    The study of adsorption phenomenon is one of the most relevant and traditional physical chemistry experiments performed by chemistry undergraduate students in laboratory courses. In this article, we describe an easy, inexpensive, and straightforward way to experimentally determine adsorption isotherms using pieces of filter paper as the adsorbent…

  15. Discerning biodegradation and adsorption of microcystin-LR in a shallow semi-enclosed bay and bacterial community shifts in response to associated process.

    PubMed

    Li, Jieming; Li, Ji; Shi, Ge; Mei, Zulin; Wang, Ruiping; Li, Dianyue

    2016-10-01

    Hepatotoxic microcystins (MCs) produced by cyanobacteria pose serious risks to aquatic ecosystems and human health, to understand elimination pathways and mechanisms for MCs, especially in a shallow and semi-enclosed eutrophic area, is of great significance. This study succeed in discerning biodegradation and adsorption of microcystin-LR (MCLR) mediated by water and/or sediment in northern part of Meiliang Bay in Lake Taihu, China, and among the first to reveal the shifts of indigenous bacterial community composition in response to MCLR-biodegradation in sediment by Illumina high-throughput sequencing (HTS). Results confirmed that biodegradation predominantly governed MCLR elimination as compared to adsorption in study area. Through faster biodegradation with a rate of 49.21μgL(-1)d(-1), lake water contributed more to overall MCLR removal than sediment. Sediment also played indispensable role in MCLR removal via primarily biodegradation by indigenous community (a rate of 17.27μgL(-1)d(-1)) and secondarily adsorption (<20% of initial concentration). HTS analysis showed that indigenous community composition shifted with decreased phylogenetic diversity in response to sediment-mediated MCLR-biodegradation. Proteobacteria became predominant (39.34-86.78%) in overall composition after biodegradation, which was mostly contributed by sharp proliferation of β-proteobacteria (22.76-74.80%), and might closely link to MCLR-biodegradation in sediment. Moreover, the members of several genera belonging to α-proteobacteria, β-proteobacteria and γ-proteobacteria seemed to be key degraders because of their dominance or increasing population as MCLR degraded. This study expands understanding on natural elimination mechanism for MCs, and provides guidance to reduce MCs' biological risks and guarantee ecosystem safety in aquatic habitats.

  16. Imprinted gold 2D nanoarray for highly sensitive and convenient PSA detection via plasmon excited quantum dots.

    PubMed

    Song, Hong Yan; Wong, Ten It; Sadovoy, Anton; Wu, Lin; Bai, Ping; Deng, Jie; Guo, Shifeng; Wang, Yi; Knoll, Wolfgang; Zhou, Xiaodong

    2015-01-07

    We designed and fabricated two new nanostructured biosensing chips, with which the sensitive detection of prostate specific antigen (PSA) as low as 100 pg ml(-1) can be achieved, by measuring the plasmon enhanced fluorescence through a conventional dark field microscope. The gold nanostructure arrays, one with gold nanopillars of 140 nm, the other with gold nanoholes of 140 nm, were fabricated via nanoimprinting onto glass substrate, as localized surface plasmon resonance (LSPR) generators to enhance the fluorescent emission of fluorophore, e.g. quantum dot (QD). A sandwich bioassay of capture anti-PSA antibody (cAb)/PSA/detection anti-PSA (dAb) labeled by QD-655 was established on the nanostructures, and the perfect LSPR excitation distance (10-15 nm) between the nanostructure and QD-655 was simulated and controlled by a cleft cAb fragment and streptavidin modified QD. QD was chosen in this study due to its photo stability, broad Stokes shift, and long lifetime. As far as we know, this is the first time that QD is applied for PSA detection on the uniform nanostructured sensing chips based on the LSPR enhanced fluorescence. Due to the miniaturized nanoarray sensing chip (1.8 mm × 1.8 mm), the convenience and specificity for the detection of PSA via the sandwich assay, and the high optical detection sensitivity, the platform has great potential for the development of a portable point-of-care (POC) system for outpatient diagnosis and treatment monitoring.

  17. Effects of PSA Removal from NCAM on the Critical Period Plasticity Triggered by the Antidepressant Fluoxetine in the Visual Cortex

    PubMed Central

    Guirado, Ramon; La Terra, Danilo; Bourguignon, Mathieu; Carceller, Hector; Umemori, Juzoh; Sipilä, Pia; Nacher, Juan; Castrén, Eero

    2016-01-01

    Neuronal plasticity peaks during critical periods of postnatal development and is reduced towards adulthood. Recent data suggests that windows of juvenile-like plasticity can be triggered in the adult brain by antidepressant drugs such as Fluoxetine. Although the exact mechanisms of how Fluoxetine promotes such plasticity remains unknown, several studies indicate that inhibitory circuits play an important role. The polysialylated form of the neural cell adhesion molecules (PSA-NCAM) has been suggested to mediate the effects of Fluoxetine and it is expressed in the adult brain by mature interneurons. Moreover, the enzymatic removal of PSA by neuroaminidase-N not only affects the structure of interneurons but also has been shown to play a role in the onset of critical periods during development. We have here used ocular dominance plasticity in the mouse visual cortex as a model to investigate whether removal of PSA might influence the Fluoxetine-induced plasticity. We demonstrate that PSA removal in the adult visual cortex alters neither the baseline ocular dominance, nor the fluoxetine-induced shift in the ocular dominance. We also show that both chronic Fluoxetine treatment and PSA removal independently increase the basal FosB expression in parvalbumin (PV) interneurons in the primary visual cortex. Therefore, our data suggest that although PSA-NCAM regulates inhibitory circuitry, it is not required for the reactivation of juvenile-like plasticity triggered by Fluoxetine. PMID:26903807

  18. Reduction of PSA values by combination pharmacological therapy in patients with chronic prostatitis: implications for prostate cancer detection.

    PubMed

    Magri, Vittorio; Trinchieri, Alberto; Montanari, Emanuele; Del Nero, Alberto; Mangiarotti, Barbara; Zirpoli, Pasquale; de Eguileor, Magda; Marras, Emanuela; Ceriani, Isabella; Vral, Anne; Perletti, Gianpaolo

    2007-06-01

    We identified from our clinical database a total of 471 patients affected by cat. II chronic bacterial prostatitis (CBP), cat. III (IIIa and IIIb) chronic pelvic pain syndrome (CP/CPPS), or cat. IV asymptomatic inflammatory prostatitis (AIP), according to NIH criteria. 132 intent-to-treat patients, showing levels of PSA > or =4 ng/mL, were subjected to a 6-week course of combination pharmacological therapy with 500 mg/day ciprofloxacin, 500 mg/day azithromycin (3 days/week), 10 mg/day alfuzosin and 320 mg b.i.d. Serenoa repens extract. At the end of treatment, 111 per-protocol patients belonging to all categories of prostatitis showed a total 32.5% reduction of PSA levels. In the same group, 66 patients (59.4%) showed "normalization" of PSA values under the 4 ng/mL limit. Patients affected by cat. IIIb CP/CPPS showed the highest PSA reduction and normalization rates (40% and 68.4%, respectively). Follow-up data show that, after a marked, significant reduction at completion of therapy, PSA levels, urine peak flow rates and NIH-CPSI symptom scores remained constant or decreased throughout a period of 18 months in patients showing normalization of PSA values. Prostatic biopsy was proposed to 45 patients showing persistently high PSA values (> or = 4 ng/mL) at the end of treatment. Fourteen patients rejected biopsy; of the remaining 31, 10 were diagnosed with prostate cancer. Four months after a first biopsy, a second biopsy was proposed to the 21 patients with a negative first diagnosis and persistently elevated PSA levels. Three patients rejected the procedure; of the remaining 18, four were diagnosed with prostatic carcinoma. In summary, combination pharmacological therapy decreased the number of patients undergoing prostatic biopsy from 111 to 45. Normalization of PSA values in 59.4% of patients--not subjected to biopsy--increased the prostate cancer detection rate from 12.6% (14/111) to 31.1% (14/45). The reduction of PSA after a 6-week course of therapy was

  19. Application of activated carbon derived from scrap tires for adsorption of Rhodamine B.

    PubMed

    Li, Li; Liu, Shuangxi; Zhu, Tan

    2010-01-01

    Activated carbon derived from solid hazardous waste scrap tires was evaluated as a potential adsorbent for cationic dye removal. The adsorption process with respect to operating parameters was investigated to evaluate the adsorption characteristics of the activated pyrolytic tire char (APTC) for Rhodamine B (RhB). Systematic research including equilibrium, kinetics and thermodynamic studies was performed. The results showed that APTC was a potential adsorbent for RhB with a higher adsorption capacity than most adsorbents. Solution pH and temperature exert significant influence while ionic strength showed little effect on the adsorption process. The adsorption equilibrium data obey Langmuir isotherm and the kinetic data were well described by the pseudo second-order kinetic model. The adsorption process followed intra-particle diffusion model with more than one process affecting the adsorption process. Thermodynamic study confirmed that the adsorption was a physisorption process with spontaneous, endothermic and random characteristics.

  20. Applications and limits of theoretical adsorption models for predicting the adsorption properties of adsorbents.

    PubMed

    Park, Hyun Ju; Nguyen, Duc Canh; Na, Choon-Ki; Kim, Chung-il

    2015-01-01

    The objective of this study is to evaluate the applicability of adsorption models for predicting the properties of adsorbents. The kinetics of the adsorption of NO3- ions on a PP-g-AA-Am non-woven fabric have been investigated under equilibrium conditions in both batch and fixed bed column processes. The adsorption equilibrium experiments in the batch process were carried out under different adsorbate concentration and adsorbent dosage conditions and the results were analyzed using adsorption isotherm models, energy models, and kinetic models. The results of the analysis indicate that the adsorption occurring at a fixed adsorbate concentration with a varying adsorbent dosage occur more easily compared to those under a fixed adsorbent dosage with a varying adsorbate concentration. In the second part of the study, the experimental data obtained using fixed bed columns were fit to Bed Depth Service Time, Bohart-Adams, Clark, and Wolborska models, to predict the breakthrough curves and determine the column kinetic parameters. The adsorption properties of the NO3- ions on the PP-g-AA-Am non-woven fabric were differently described by different models for both the batch and fixed bed column process. Therefore, it appears reasonable to assume that the adsorption properties were dominated by multiple mechanisms, depending on the experimental conditions.

  1. Methylene blue adsorption from aqueous solution by activated carbon: effect of acidic and alkaline solution treatments.

    PubMed

    Ijagbemi, Christianah O; Chun, Ji I; Han, Da H; Cho, Hye Y; O, Se J; Kim, Dong S

    2010-01-01

    The removal of Methylene Blue (MB) from aqueous solution using activated carbon (AC) has been investigated. Adsorption experiments were conducted and the maximum adsorption capacity was determined. The effect of experimental parameters such as pH, dye concentration and temperature were studied on the adsorption process. Equilibrium data were mathematically modeled using the Langmuir and Freundlich adsorption models to describe the equilibrium isotherms at different dye concentrations and temperature. Parameters of best-fit model were calculated and discussed. To understand the mechanism of adsorption, kinetic models were employed to follow the adsorption processes; the pseudo-first-order best described the adsorption of MB onto AC. It was found that pH plays a major role in the adsorption process; adsorption capacity was influenced by the physical and surface chemical properties of carbon and the pH of the solution. 99.0% MB removal was achieved at equilibrium.

  2. Ionic Adsorption and Desorption of CNT Nanoropes

    PubMed Central

    Shang, Jun-Jun; Yang, Qing-Sheng; Yan, Xiao-Hui; He, Xiao-Qiao; Liew, Kim-Meow

    2016-01-01

    A nanorope is comprised of several carbon nanotubes (CNTs) with different chiralities. A molecular dynamic model is built to investigate the ionic adsorption and desorption of the CNT nanoropes. The charge distribution on the nanorope is obtained by using a modified gradient method based on classical electrostatic theory. The electrostatic interactions among charged carbon atoms are calculated by using the Coulomb law. It was found here that the charged nanorope can adsorb heavy metal ions, and the adsorption and desorption can be realized by controlling the strength of applied electric field. The distance between the ions and the nanorope as well as the amount of ions have an effect on the adsorption capacity of the nanorope. The desorption process takes less time than that of adsorption. The study indicates that the CNT nanorope can be used as a core element of devices for sewage treatment. PMID:28335306

  3. Genome-wide Association Study Identifies Loci at ATF7IP and KLK2 Associated with Percentage of Circulating Free PSA1 2

    PubMed Central

    Jin, Guangfu; Zheng, Siqun Lilly; Lilja, Hans; Kim, Seong-Tae; Tao, Sha; Gao, Zhengrong; Young, Tracey; Wiklund, Fredrik; Feng, Junjie; Isaacs, William B; Rittmaster, Roger S; Gronberg, Henrik; Condreay, Lynn D; Sun, Jielin; Xu, Jianfeng

    2013-01-01

    Background Percentage of free-to-total prostate-specific antigen (%fPSA) is an independent predictor of risk for prostate cancer among men with modestly elevated level of total PSA (tPSA) in blood. Physiological and pathological factors have been shown to influence the %fPSA value and diagnostic accuracy. Materials/Methods To evaluate genetic determinants of %fPSA, we conducted a genome-wide association study of serum %fPSA by genotyping 642,584 single nucleotide polymorphisms (SNPs) in 3192 men of European ancestry, each with a tPSA level of 2.5 to 10 ng/ml, that were recruited in the REduction by DUtasteride of Prostate Cancer Events study. Single nucleotide polymorphisms (SNPs) with P < 10-5 were further evaluated among the controls of a population-based case-control study in Sweden (2899 prostate cancer cases and 1722 male controls), including 464 controls having tPSA levels of 2.5 to 10 ng/ml. Results We identified two loci that were associated with %fPSA at a genome-wide significance level (P <5 x 10-8). The first associated SNP was rs3213764 (P = 6.45 x 10-10), a nonsynonymous variant (K530R) in the ATF7IP gene at 12p13. This variant was also nominally associated with tPSA (P = .015). The second locus was rs1354774 (P = 1.25 x 10-12), near KLK2 at 19q13, which was not associated with tPSA levels, and is separate from the rs17632542 locus at KLK3 that was previously associated with tPSA levels and prostate cancer risk. Neither rs3213764 nor rs1354774 was associated with prostate cancer risk or aggressiveness. Conclusions These findings demonstrate that genetic variants at ATF7IP and KLK2 contribute to the variance of %fPSA. PMID:23359319

  4. Differential Heat of Adsorption and Isosteres.

    PubMed

    Tian, Yun; Wu, Jianzhong

    2017-01-31

    Heat of adsorption is a basic thermodynamic property extensively used not only for understanding thermal effects and heat management in industrial gas storage and separation processes but also for development and validation of adsorption models and materials force fields. Despite a long history of theoretical studies and a vast experimental literature, controversies often arise in the thermodynamic analysis of heat effects due to various assumptions used to describe gas adsorption and inconsistencies between direct calorimetric measurements and isosteric heat obtained from various adsorption isotherms. Here we present a rigorous theoretical procedure for predicting isosteric heat without any assumption about the geometry of porous adsorbents or operating conditions. Quantitative relations between the differential heat and various isosteres have been established with the grand-canonical Monte Carlo simulation for gas adsorption in amorphous as well as crystalline porous materials. The inconsistencies and practical issues with conventional methods for the analysis of the heat effect have been clarified in the context of the exact results for model systems. Via the resolution of a number of controversies about heat analysis, we hope that the new theoretical procedure will be adopted for both fundamental research and industrial applications of gas adsorption processes.

  5. Exposure to Agent Orange is a significant predictor of prostate-specific antigen (PSA)-based recurrence and a rapid PSA doubling time after radical prostatectomy

    PubMed Central

    Shah, Sagar R.; Freedland, Stephen J.; Aronson, William J.; Kane, Christopher J.; Presti, Joseph C.; Amling, Christopher L.; Terris, Martha K.

    2011-01-01

    OBJECTIVE To investigate and report the clinicopathological characteristics and outcomes after radical prostatectomy (RP) in patients with prostate cancer and previous exposure to Agent Orange (AO), particularly in relationship to race. PATIENTS AND METHODS In 1495 veterans who had undergone RP the clinicopathological characteristics, biochemical progression rates, and prostate-specific antigen (PSA) doubling time (DT) after recurrence between AO-exposed and unexposed men were compared using logistic and linear regression and Cox proportional hazards analyses, and stratified by race. RESULTS The 206 (14%) men with AO exposure were more likely to be black (P = 0.001), younger (P < 0.001), treated more recently (P < 0.001), have a higher body mass index (P = 0.001), have clinical stage T1 disease (P < 0.001), and have lower preoperative PSA levels (P = 0.001). After adjusting for several clinical characteristics, AO exposure was not significantly related to adverse pathological features but was significantly associated with biochemical progression risk (relative risk 1.55, 95% confidence interval 1.15–2.09, P = 0.004) and shorter PSADT (P < 0.001) after recurrence (8.2 vs 18.6 months). When stratified by race, these associations were present and similar in both races, with no significant interaction between race and AO exposure for predicting biochemical recurrence or mean adjusted PSADT (P interaction >0.20). CONCLUSIONS Patients with AO exposure and treated with RP were more likely to be black, present with lower risk features, have an increased risk of biochemical progression, and shorter PSADT after recurrence. When stratified by race, the association between AO exposure and poor outcomes was present in both races. These findings suggest that among selected men who choose RP, AO exposure might be associated with more aggressive prostate cancer. PMID:19298411

  6. [Adsorption kinetics and mechanism of lead (II) on polyamine-functionalized mesoporous activated carbon].

    PubMed

    Li, Kun-Quan; Wang, Yan-Jin; Yang, Mei-Rong; Zhu, Zhi-Qiang; Zheng, Zheng

    2014-08-01

    Bagasse mesoporous carbon was prepared by microwave assisted H3 PO4 activation. Amido and imido groups were modified with ethanediamine on the channels' surface of mesoporous carbon through nitric oxidation and amide reaction. The influence of Pb(II) concentration, adsorption time on Pb(II) adsorption on the ethanediamine-modified mesoporous carbon (AC-EDA) was investigated. The adsorption kinetics and mechanism were also discussed. The results showed that AC-EDA had a great performance for Pb(II) adsorption, and more than 70% of Pb(II) was adsorbed in 5 minutes. The adsorption amount of Pb(II) on the carbon increased with the increase of solution pH in acidic conditions. It was found that AC-EDA had different binding energies on different adsorption sites for Pb(II) separation. The Pb(II) adsorption process on AC-EDA was controlled by intra-particle diffusion in the first 3 min, and then film diffusion played the important pole on the adsorption. The adsorption amount increased with the increase of temperature, indicating the adsorption was an endothermic reaction. The high adsorption energy (> 11 kJ x mol(-1)) implied that the) adsorption was a chemical adsorption. The XPS of AC-EDA before and after Pb(II) adsorption showed that the polyamine group was involved in the adsorption, and should be a main factor of the high efficient adsorption.

  7. Adsorption Behavior of Nonplanar Phthalocyanines: Competition of Different Adsorption Conformations

    PubMed Central

    2016-01-01

    Using density functional theory augmented with state-of-the-art van der Waals corrections, we studied the geometric and electronic properties of nonplanar chlorogallium-phthalocyanine GaClPc molecules adsorbed on Cu(111). Comparing these results with published experimental data for adsorption heights, we found indications for breaking of the metal–halogen bond when the molecule is heated during or after the deposition process. Interestingly, the work-function change induced by this dissociated geometry is the same as that computed for an intact adsorbate layer in the “Cl-down” configuration, with both agreeing well with the experimental photoemission data. This is unexpected, as the chemical natures of the adsorbates and the adsorption distances are markedly different in the two cases. The observation is explained as a consequence of Fermi-level pinning due to fractional charge transfer at the interface. Our results show that rationalizing the adsorption configurations on the basis of electronic interface properties alone can be ambiguous and that additional insight from dispersion-corrected DFT simulations is desirable. PMID:27066160

  8. Prognostic value of PSA nadir {<=}4 ng/mL within 4 months of high-dose radiotherapy for locally advanced prostate cancer

    SciTech Connect

    Nickers, Philippe . E-mail: philippe.nickers@skynet.be; Albert, Adelin; Waltregny, David; Deneufbourg, Jean-Marie

    2006-05-01

    Purpose: To investigate early prostate-specific antigen (PSA) kinetics after high radiation doses of 85 Gy on locally advanced prostate cancer. Methods and Materials: A total of 201 patients were prospectively and consecutively treated with external beam radiotherapy and a brachytherapy boost. Of the 201 patients, 104 received concomitant hormonal therapy on the decision of the referring urologist and were excluded, yielding a study population of 97 patients. The first posttreatment PSA analysis was performed not earlier than 1 month after treatment completion but within the first 4 months, and then every 4 months. Analysis of PSA kinetics included the PSA nadir (nPSA) at values of {<=}4 ng/mL to {<=}0.5 ng/mL. The nPSA at {<=}4 ng/mL within 4 months (nPSA {<=}4/4m) was the variable of interest. Results: We established highly significant associations between an nPSA of {<=}1 and {<=}0.5 ng/mL and the nPSA {<=}4/4m (p <0.0001). A hazard ratio of 0.33 (95% Confidence Interval (CI), 0.12-0.91) underlined the lower risk of recurrence related to nPSA {<=}4/4m achievement (p = 0.033). Using time-dependent covariate models for patients who did not reach an nPSA {<=}4/4m, an nPSA of {<=}1 ng/mL remained without prognostic significance (p = 0.06). However, for patients who reached an nPSA {<=}4/4m, an nPSA of {<=}1 ng/mL did significantly improve the prognosis (p <0.001), but much later after treatment. The same analysis was repeated for nPSA {<=}0.5 ng/mL with similar conclusions as when nPSA {<=}4/4m was obtained (p <0.01). Conclusion: The nPSA {<=}4/4m has been demonstrated to be a significant predictor of biochemical no evidence of disease after high radiation doses of 85 Gy. Its major advantage is that it was available earlier than the other nadirs.

  9. Impact of Ultrahigh Baseline PSA Levels on Biochemical and Clinical Outcomes in Two Radiation Therapy Oncology Group Prostate Clinical Trials

    SciTech Connect

    Rodrigues, George; Bae, Kyounghwa; Roach, Mack; Lawton, Colleen; Donnelly, Bryan; Grignon, David; Hanks, Gerald; Porter, Arthur; Lepor, Herbert; Sandler, Howard

    2011-06-01

    Purpose: To assess ultrahigh (UH; prostate-specific antigen [PSA]levels {>=}50 ng/ml) patient outcomes by comparison to other high-risk patient outcomes and to identify outcome predictors. Methods and Materials: Prostate cancer patients (PCP) from two Phase III Radiation Therapy Oncology Group clinical trials (studies 9202 and 9413) were divided into two groups: high-risk patients with and without UH baseline PSA levels. Predictive variables included age, Gleason score, clinical T stage, Karnofsky performance score, and treatment arm. Outcomes included overall survival (OS), distant metastasis (DM), and biochemical failure (BF). Unadjusted and adjusted hazard ratios (HRs) were calculated using either the Cox or Fine and Gray's regression model with associated 95% confidence intervals (CI) and p values. Results: There were 401 patients in the UH PSA group and 1,792 patients in the non-UH PSA PCP group of a total of 2,193 high-risk PCP. PCP with UH PSA were found to have inferior OS (HR, 1.19; 95% CI, 1.02-1.39, p = 0.02), DM (HR, 1.51; 95% CI, 1.19-1.92; p = 0.0006), and BF (HR, 1.50; 95% CI, 1.29-1.73; p < 0.0001) compared to other high-risk PCP. In the UH cohort, PSA level was found to be a significant factor for the risk of DM (HR, 1.01; 95% CI, 1.001-1.02) but not OS and BF. Gleason grades of 8 to 10 were found to consistently predict for poor OS, DM, and BF outcomes (with HR estimates ranging from 1.41-2.36) in both the high-risk cohort and the UH cohort multivariable analyses. Conclusions: UH PSA levels at diagnosis are related to detrimental changes in OS, DM, and BF. All three outcomes can be modeled by various combinations of all predictive variables tested.

  10. Statins and Metformin Use Is Associated with Lower PSA Levels in Prostate Cancer Patients Presenting for Radiation Therapy

    PubMed Central

    Liu, Xiaonan; Li, Jing; Schild, Steven E.; Schild, Michael H.; Wong, William; Vora, Sujay; Herman, Michael G.; Fatyga, Mirek

    2017-01-01

    Background A possible association between the level of prostate specific antigen (PSA) and the use of some commonly prescribed medications has been reported in recent studies. Most of these studies were carried out in general populations of men who were screened for prostate cancer using the PSA test. We reported on the association between the initial PSA level and the use of statins, metformin and alpha-blockers in patients who were diagnosed with prostate cancer and presented for radiation therapy. Methods Three hundred and eighty one patients treated between the years of 2000-2005 and 2009-2012 were included in this retrospective study. The information about statin, metformin and alpha-blockers use was recorded immediately prior to treatment. Differences in PSA levels prior to treatment by medication status were estimated using univa-riate and multivariate linear regression on log PSA values. Results Compared with men who were not on these medications, the PSA level at presentation was 20% lower for statin users (p = 0.002) and 33% lower for metformin users (p = 0.004). We did not observe statistically significant associations between the use of statins or metformin and cancer stage, National Comprehensive Cancer Network (NCCN) risk score, or therapy outcome. A statistically significant association between the NCCN risk score and the use of alpha-blockers was observed (p = 0.002). Conclusions We found that statins and metformin were associated with lower PSA levels in prostate cancer patients to an extent that could influence management decisions. We found no statistically significant associations between the use of these medications and treatment outcomes. PMID:28239505

  11. The Effect of Increasing Doses of Saw Palmetto Fruit Extract on Serum PSA Levels: Analysis of the CAMUS Randomized Trial

    PubMed Central

    Andriole, Gerald L.; McCullum-Hill, Christie; Sandhu, Gurdarshan S.; Crawford, E. David; Barry, Michael J.; Cantor, Alan

    2014-01-01

    Purpose Saw palmetto extracts are used for treating lower urinary tract symptoms in men despite level I evidence concluding that saw palmetto was ineffective in reducing lower urinary symptoms. We sought to determine whether higher doses of saw palmetto as studied in CAMUS affect serum PSA levels. Materials and Methods The CAMUS trial was a randomized, placebo-controlled double blind multi-centered North American trial conducted between June 5, 2008 and October 10, 2012 in which 369 men >45 years of age with AUA symptom score ≥ 8 and ≤ 24 were randomly assigned to placebo or dose escalation saw palmetto, which consisted of 320mg for first 24 weeks to 640mg for next 24 weeks to 960mg for last 24 weeks of this 72 week trial. Serum PSA levels (Beckman-Coulter) were obtained at baseline and at weeks 24, 48 and 72 and were compared between treatment groups using the pooled t and Fisher's exact tests. Results Serum PSA levels were similar at baseline for the placebo (1.93 ± 1.59 ng/ml) and saw palmetto groups (2.20 ± 1.95, p = 0.16). Changes in PSA levels over the course of the study were similar: placebo group mean change 0.16 ± 1.08 ng/ml and saw palmetto group mean change 0.23 ± 0.83 ng/ml (p value 0.50). Additionally, no differential effect on serum PSA levels was observed between treatment arms when groups were stratified by baseline PSA values. Conclusions Saw palmetto extract does not affect serum PSA levels more than placebo even at relatively high doses. PMID:23253958

  12. Can Urinary PCA3 Supplement PSA in the Early Detection of Prostate Cancer?

    PubMed Central

    Wei, John T.; Feng, Ziding; Partin, Alan W.; Brown, Elissa; Thompson, Ian; Sokoll, Lori; Chan, Daniel W.; Lotan, Yair; Kibel, Adam S.; Busby, J. Erik; Bidair, Mohamed; Lin, Daniel W.; Taneja, Samir S.; Viterbo, Rosalia; Joon, Aron Y.; Dahlgren, Jackie; Kagan, Jacob; Srivastava, Sudhir; Sanda, Martin G.

    2014-01-01

    Purpose Given the limited sensitivity and specificity of prostate-specific antigen (PSA), its widespread use as a screening tool has raised concerns for the overdiagnosis of low-risk and the underdiagnosis of high-grade prostate cancer. To improve early-detection biopsy decisions, the National Cancer Institute conducted a prospective validation trial to assess the diagnostic performance of the prostate cancer antigen 3 (PCA3) urinary assay for the detection of prostate cancer among men screened with PSA. Patients and Methods In all, 859 men (mean age, 62 years) from 11 centers scheduled for a diagnostic prostate biopsy between December 2009 and June 2011 were enrolled. The primary outcomes were to assess whether PCA3 could improve the positive predictive value (PPV) for an initial biopsy (at a score > 60) and the negative predictive value (NPV) for a repeat biopsy (at a score < 20). Results For the detection of any cancer, PPV was 80% (95% CI, 72% to 86%) in the initial biopsy group, and NPV was 88% (95% CI, 81% to 93%) in the repeat biopsy group. The addition of PCA3 to individual risk estimation models (which included age, race/ethnicity, prior biopsy, PSA, and digital rectal examination) improved the stratification of cancer and of high-grade cancer. Conclusion These data independently support the role of PCA3 in reducing the burden of prostate biopsies among men undergoing a repeat prostate biopsy. For biopsy-naive patients, a high PCA3 score (> 60) significantly increases the probability that an initial prostate biopsy will identify cancer. PMID:25385735

  13. Adsorption coefficients for TNT on soil and clay minerals

    NASA Astrophysics Data System (ADS)

    Rivera, Rosángela; Pabón, Julissa; Pérez, Omarie; Muñoz, Miguel A.; Mina, Nairmen

    2007-04-01

    To understand the fate and transport mechanisms of TNT from buried landmines is it essential to determine the adsorption process of TNT on soil and clay minerals. In this research, soil samples from horizons Ap and A from Jobos Series at Isabela, Puerto Rico were studied. The clay fractions were separated from the other soil components by centrifugation. Using the hydrometer method the particle size distribution for the soil horizons was obtained. Physical and chemical characterization studies such as cation exchange capacity (CEC), surface area, percent of organic matter and pH were performed for the soil and clay samples. A complete mineralogical characterization of clay fractions using X-ray diffraction analysis reveals the presence of kaolinite, goethite, hematite, gibbsite and quartz. In order to obtain adsorption coefficients (K d values) for the TNT-soil and TNT-clay interactions high performance liquid chromatography (HPLC) was used. The adsorption process for TNT-soil was described by the Langmuir model. A higher adsorption was observed in the Ap horizon. The Freundlich model described the adsorption process for TNT-clay interactions. The affinity and relative adsorption capacity of the clay for TNT were higher in the A horizon. These results suggest that adsorption by soil organic matter predominates over adsorption on clay minerals when significant soil organic matter content is present. It was found that, properties like cation exchange capacity and surface area are important factors in the adsorption of clayey soils.

  14. Experimental set-up for three PHOEBUS type large-area heliostats at the PSA

    SciTech Connect

    Haeger, M.; Schiel, W.; Romero, M.; Schmitz-Goeb, M.

    1995-11-01

    Three large-area heliostat prototypes are being erected at the Plataforma Solar de Almeria by Spanish and German industry. The objective is to demonstrate their technical and economical suitability for a PHOEBUS power tower plant. The two different heliostat designs including two 100 ml glass/metal faceted heliostats and one 150 m{sup 2} stressed membrane heliostat are tested at a representative distance of 485 m to the PSA`s CESA tower. The paper introduces the heliostat designs and test set-up, such as location, targets, flux measurement, data acquisition and control.

  15. Adsorption of deamidated antibody variants on macroporous and dextran-grafted cation exchangers: II. Adsorption kinetics.

    PubMed

    Tao, Yinying; Carta, Giorgio; Ferreira, Gisela; Robbins, David

    2011-03-18

    Single and multicomponent batch adsorption kinetics were obtained for deamidated mAb variants on two commercial cation exchangers, one with an open macroporous structure--UNOsphere S--and the other with charged dextran grafts--Capto S. The adsorption kinetics for the macroporous matrix was found to be controlled largely by pore diffusion. The effective diffusivity estimated from single component data was a fraction of the mAb free solution diffusivity, and its value could be used to accurately predict the adsorption kinetics for two- and three-component systems. In this case, when two or more variants were adsorbed simultaneously, both experimental and predicted results showed a temporary overshoot of the amount adsorbed above the equilibrium value for the more deamidated variant followed by a gradual approach to equilibrium. Adsorption rates on the dextran grafted material were much faster than those observed for the macroporous matrix for both single component and simultaneous adsorption cases. In this case, no significant overshoot was observed for the more deamidated forms. The Capto S adsorption kinetics could be described well by a diffusion model with an adsorbed phase driving force for single component adsorption and for the simultaneous adsorption of multiple variants. However, this model failed to predict the adsorption kinetics when more deamidated forms pre-adsorbed on the resin were displaced by less deamidated ones. In this case, the kinetics of the displacement process was much slower indicating that the pre-adsorbed components severely hindered transport of the more strongly bound variants. Overall, the results indicate that despite the lower capacity, the macroporous resin may be more efficient in process applications where displacement of one variant by another takes place as a result of the faster and more predictable kinetics.

  16. Adsorption mechanism of chloroacetanilide herbicides to modified montmorillonite.

    PubMed

    El-Nahhal, Yasser

    2003-09-01

    This study was undertaken to characterize the adsorption mechanism of alachlor and metolachlor on montmorillonite modified with cationic surfactants. Adsorbed amounts of cationic surfactant on montmorillonite surfaces were determined by CNHSO analyzer. Equilibrium concentrations of alachlor and metolachlor were determined by GC and adsorption results were fit to a linear regression equation. The slope of the isotherms (Kd) was normalized to the fraction of organic carbon on montmorillonite complexes to produce corresponding Koc. Adsorption of surfactants fit very well to Langmuir equation. Increased basal spacing indicates that surfactant molecules could penetrate through the interlayer spacing and arrange themselves in different ways. Equilibrium data of alachlor and metolachlor suggest that adsorption may occur via physical or chemical bonds. Koc values of alachlor or metolachlor decreased as the fraction of the organic carbon increased in montmorillonite complexes indicating independent adsorption process. Changes of the molar free energy of the adsorption reactions were in the range of physical adsorption, indicating that adsorption reactions are spontaneous and the molecules either adsorb on the surface or penetrate into the inter-layers of montmorillonite-surfactant complex. Careful investigation of the adsorption data suggests that interaction may occur via the active groups such as carbonyl group (-C=O), anilidic (C-N) group and/or phenyl rings. This information may provide better understanding on adsorption mechanism and be useful in designing ecologically acceptable herbicide formulations.

  17. Age-Adjusted PSA Levels in Prostate Cancer Prediction: Updated Results of the Tyrol Prostate Cancer Early Detection Program

    PubMed Central

    Heidegger, Isabel; Fritz, Josef; Klocker, Helmut; Pichler, Renate

    2015-01-01

    Objective To reduce the number of unnecessary biopsies in patients with benign prostatic disease, however, without missing significant PCa the present study re-evaluates the age-dependent PSA cut-offs in the Tyrol Prostate Cancer (PCa) early detection program. Patients and Methods The study population included 2225 patients who underwent prostate biopsy due to elevated PSA levels at our department. We divided our patient collective into four age groups: ≤49 years (n = 178), 50-59 years (n = 597), 60-69 years (n = 962) and ≥70 years (n = 488). We simulated different scenarios for PSA cut-off values between 1.25 and 6 ng/mL and fPSA% between 15 and 21% for all four age groups and calculated sensitivity, specificity, confidence intervals and predictive values. Results PCa was detected in 1218 men (54.7%). We found that in combination with free PSA ≤21% the following PSA cut-offs had the best cancer specificity: 1.75 ng/ml for men ≤49 years and 50-59 years, 2.25 ng/ml for men aged 60-69 years and 3.25 ng/ml for men ≥70 years. Using these adjusted PSA cut-off values all significant tumors are recognized in all age groups, yet the number of biopsies is reduced. Overall, one biopsy is avoided in 13 to 14 men (number needed to screen = 13.3, reduction of biopsies = 7.5%) when decision regarding biopsy is done according to the “new” cut-off values instead of the “old” ones. For the different age groups the number needed to screen to avoid one biopsy varied between 9.2 (≤49 years) and 17.4 (50-59 years). Conclusion With “new”, fine-tuned PSA cut-offs we detect all relevant PCa with a significant reduction of biopsies compared to the “old” cut-off values. Optimization of age-specific PSA cut-offs is one step towards a smarter strategy in the Tyrol PCa Early Detection Program. PMID:26218594

  18. A claudin 3 and claudin 4-targeted Clostridium perfringens protoxin is selectively cytotoxic to PSA-producing prostate cancer cells.

    PubMed

    Romanov, Victor; Whyard, Terry C; Waltzer, Wayne C; Gabig, Theodore G

    2014-09-01

    Prostate cancer is the second leading cause of non-cutaneous cancer-related death in males, and effective strategies for treatment of metastatic disease are currently limited. The tight junction proteins, claudin 3 and claudin 4, serve as cell-surface receptors for the pore-forming Clostridium perfringens enterotoxin [CPE]. Most prostate cancer cells overexpress claudin 3 and claudin 4, and claudins are aberrantly distributed over the plasma membrane, making these cells particularly sensitive to cytolysis by CPE. Prostate cancer cells secrete PSA locally that is proteolytically active; however, circulating PSA is inactivated via binding to protease inhibitors. To overcome systemic toxicity of CPE, a modified protoxin was constructed with a tethered ligand attached to the C-terminus connected by a flexible linker containing a PSA-specific protease cleavage site. This engineered protoxin selectively and efficiently lyses PSA-producing prostate cancer cells whereas CLDN3 and CLDN4 positive cells that do not express PSA are resistant to cytolysis.

  19. Study on the adsorption feature of rutin aqueous solution on macroporous adsorption resins.

    PubMed

    Chen, Zhenbin; Zhang, Anjie; Li, Jie; Dong, Fang; Di, Duolong; Wu, Youzhi

    2010-04-15

    The adsorption feature of different kinds of polystyrene-based macroporous adsorption resins (MARs) was investigated systemically at constant temperature employing Rutin as the adsorbate. Different from traditional adsorption patterns, Langmuir and Freundlich adsorption, and the results showed interesting aspects: (1) With the increase of the volume of the initial solution, the adsorption capacity increased to the maximum, and then decreased gradually. (2) Experimental results clearly verified the opinion that the adsorption process of MARs could be divided into three stages-macropores, mesopores, and micropores-by the capillary effects occurring at the two intersections, and the adsorption feature for every stage could be described well by the fourth type of Brunauer model. (3) The model that the inductive effect transmitted to the first layer could not interpret our experimental results reasonably. Thus, the model that the inductive effect passed on to a higher layer was proposed by investigating regression of the experimental results and the conclusion that the inductive effect transmitted to the third layer was drawn.

  20. Adsorption studies of methylene blue dye on tunisian activated lignin

    NASA Astrophysics Data System (ADS)

    Kriaa, A.; Hamdi, N.; Srasra, E.

    2011-02-01

    Activated carbon prepared from natural lignin, providing from a geological deposit, was used as the adsorbent for the removal of methylene blue (MB) dye from aqueous solutions. Batch adsorption studies were conducted to evaluate various experimental parameters like pH and contact time for the removal of this dye. Effective pH for MB removal was 11. Kinetic study showed that the adsorption of dye was gradual process. Quasi equilibrium reached in 4 h. Pseudo-first-order, pseudo-second-order were used to fit the experimental data. Pseudo-second-order rate equation was able to provide realistic description of adsorption kinetics. The experimental isotherms data were also modelled by the Langmuir and Freundlich equation of adsorption. Equilibrium data fitted well with the Langmuir model with maximum monolayer adsorption capacity of 147 mg/g. Activated lignin was shown to be a promising material for adsorption of MB from aqueous solutions.

  1. Adsorption properties and gaseous mercury transformation rate of natural biofilm.

    PubMed

    Cheng, Jinping; Zhao, Wenchang; Liu, Yuanyuan; Wu, Cheng; Liu, Caie; Wang, Wenhua

    2008-11-01

    Biofilms were developed on glass microscope slides in a natural aquatic environment and their mercury adsorption properties were evaluated. Results demonstrated that the biofilms contained a large number of bacterial cells and associated extracellular polymers. Mercury forms detected in the biofilms were mainly bound to residual matter and organic acids. The adsorption processes could be described by a Langmuir isotherm. The optimum conditions for adsorption of mercury to natural biofilm were an ionic strength of 0.1 mol/L, pH 6 and an optimum adsorption time of 40 min. The transformation rate was 0.79 microg gaseous mercury per gram of biofilm.

  2. Adsorption of aqueous copper on peanut hulls

    NASA Astrophysics Data System (ADS)

    Davis, Kanika Octavia

    A method was established for measuring the adsorption of Cu(II) from aqueous solution to unmodified and modified peanut hulls at constant temperature and pH. Modification of the hulls was performed by oxidation with alkaline hydrogen peroxide. During the modification process, the hydrogen peroxide solubilizes the lignin component, making the surface more porous which increases the availability of binding sites, while simultaneously oxidizing the cellulose. The oxidation of alcohol groups creates more binding sites by creating functional groups such as COO-, which increases chelation to metal ions. Fourier transform infrared spectroscopy confirms delignification of the peanut hulls by the disappearance of carboxyl peaks of the modified hulls, which were originally produced from the lignin content. Although, oxidation is not fully confirmed, it is not ruled out because the expected carboxylate peak (1680 cm-1) maybe overshadowed by a broad peak due to OH bending of water adsorbed to the hulls. Hulls adsorbed copper from solutions in the concentration range of 50-1000 ppm of CuCl2. Concentrations of pre- and post-adsorption solutions were determined using inductively coupled plasma optical emission spectroscopy. The adsorption isotherms were fit to known two and three-parameter models, evaluated and the binding mechanism was inferred. Maximum surface coverage was 3.5 +/- 0.6 mg Cu2+ /g hull for unmodified hulls and 11 +/- 1 mg Cu2+/g hull for modified hulls. The adsorption for the hulls is best described by the Langmuir model, suggesting monolayer, homogeneous adsorption. With a free energy of adsorption of 10.5 +/- 0.9 kJ/mol for unmodified hulls and 14.5 +/-0.4 kJ/mol for modified hulls, the process is categorized as chemisorption for both types of hulls. The adsorption for both hulls is also described by the Redlich-Peterson model, giving beta nearer to 1 than 0, which further suggests homogeneous adsorption described by the Langmuir model. After rinsing the hulls

  3. Hydrogen production with CO 2 capture by coupling steam reforming of methane and chemical-looping combustion: Use of an iron-based waste product as oxygen carrier burning a PSA tail gas

    NASA Astrophysics Data System (ADS)

    Ortiz, María; Gayán, Pilar; de Diego, Luis F.; García-Labiano, Francisco; Abad, Alberto; Pans, Miguel A.; Adánez, Juan

    In this work it is analyzed the performance of an iron waste material as oxygen carrier for a chemical-looping combustion (CLC) system. CLC is a novel combustion technology with the benefit of inherent CO 2 separation that can be used as a source of energy for the methane steam reforming process (SR). The tail gas from the PSA unit is used as fuel in the CLC system. The oxygen carrier behaviour with respect to gas combustion was evaluated in a continuous 500 W th CLC prototype using a simulated PSA off-gas stream as fuel. Methane or syngas as fuel were also studied for comparison purposes. The oxygen carrier showed enough high oxygen transport capacity and reactivity to fully convert syngas at 880 °C. However, lower conversion of the fuel was observed with methane containing fuels. An estimated solids inventory of 1600 kg MW th -1 would be necessary to fully convert the PSA off-gas to CO 2 and H 2O. An important positive effect of the oxygen carrier-to-fuel ratio up to 1.5 and the reactor temperature on the combustion efficiency was found. A characterization of the calcined and after-used particles was carried out showing that this iron-based material can be used as oxygen carrier in a CLC plant since particles maintain their properties (reactivity, no agglomeration, high durability, etc.) after more than 111 h of continuous operation.

  4. Modeling adsorption: Investigating adsorbate and adsorbent properties

    NASA Astrophysics Data System (ADS)

    Webster, Charles Edwin

    1999-12-01

    Surface catalyzed reactions play a major role in current chemical production technology. Currently, 90% of all chemicals are produced by heterogeneously catalyzed reactions. Most of these catalyzed reactions involve adsorption, concentrating the substrate(s) (the adsorbate) on the surface of the solid (the adsorbent). Pore volumes, accessible surface areas, and the thermodynamics of adsorption are essential in the understanding of solid surface characteristics fundamental to catalyst and adsorbent screening and selection. Molecular properties such as molecular volumes and projected molecular areas are needed in order to convert moles adsorbed to surface volumes and areas. Generally, these molecular properties have been estimated from bulk properties, but many assumptions are required. As a result, different literature values are employed for these essential molecular properties. Calculated molar volumes and excluded molecular areas are determined and tabulated for a variety of molecules. Molecular dimensions of molecules are important in the understanding of molecular exclusion as well as size and shape selectivity, diffusion, and adsorbent selection. Molecular dimensions can also be used in the determination of the effective catalytic pore size of a catalyst. Adsorption isotherms, on zeolites, (crystalline mineral oxides) and amorphous solids, can be analyzed with the Multiple Equilibrium Analysis (MEA) description of adsorption. The MEA produces equilibrium constants (Ki), capacities (ni), and thermodynamic parameters (enthalpies, ΔHi, and entropies, ΔSi) of adsorption for each process. Pore volumes and accessible surface areas are calculated from the process capacities. Adsorption isotherms can also be predicted for existing and new adsorbate-adsorbent systems with the MEA. The results show that MEA has the potential of becoming a standard characterization method for microporous solids that will lead to an increased understanding of their behavior in gas

  5. [Adsorption of Cd2+ on biochar from aqueous solution].

    PubMed

    Guo, Wen-juan; Liang, Xue-feng; Lin, Da-song; Xu, Ying-ming; Wang, Lin; Sun, Yue-bing; Qin, Xu

    2013-09-01

    Biomass-based materials such as biochar have a good performance in heavy metal adsorption. The adsorption of Cd2+ on biochar converted from cotton straw was studied. Adsorption isotherm, kinetics and effect factors such as temperature, pH and ionic strength were investigated. The adsorption of Cd2+ on biochar can be fitted by the Freundlich isotherm better than the Langmuir isotherm. The maximum adsorption amounts of Cd2+ at different temperatures were 9.738 mg x g(-1) (288.15 K), 10.14 mg x g(-1) (298.15 K), 10.40 mg x g(-1) (308.15 K) and 10.71 mg x g(-1) (318.15 K), respectively. The free energies AG(theta) were from -8.346 kJ x mol(-1) to -10.276 kJ x mol(-1) at different temperatures, indicating that the adsorption of Cd2+ onto biochar is spontaneous and is an endothermic process. The adsorption process can reach equilibrium within 40 minutes and can be fitted by the pseudo second order kinetic model. pH showed a significant effect on the adsorption of Cd2+ on biochar in the range of 2-8. The adsorption amount of Cd2+ on biochar shows a reducing trend with the increasing ionic strength.

  6. The helix-loop-helix Id-1 inhibits PSA expression in prostate cancer cells.

    PubMed

    Zielinski, Anne J; Fong, Sylvia; Allison, Juanita; Kawahara, Misako; Coppe, Jean-Philippe; Feiler, Heidi; Lee, Nancy M; Desprez, Pierre-Yves

    2010-05-15

    The inhibitor of basic helix-loop-helix transcription factors, Id-1, is an important gene whose expression increases during prostate cancer progression and that upregulates proliferation, migration and invasion. We used microarray analysis to identify the downstream genes whose transcriptional expression is modulated by Id-1 protein. We compared gene expression in control LNCaP cells and Id-1-transduced LNCaP cells, which become significantly more aggressive after Id-1 overexpression, thus mimicking the high levels of Id-1 detected in metastatic cell lines. We used the Affy HTA U133A Expression Arrays with 45,000 probe sets representing more than 39,000 transcripts. We found that one of the most significantly downregulated genes on Id-1 expression was kallikrein 3 [also called prostate specific antigen (PSA)], the most commonly used biomarker of prostate cancer. Here, we show that the reduction in PSA mRNA and protein expression associated with high-grade prostate cancers, which generally express high levels of Id-1, could be the consequence of Id-1 overexpression.

  7. Enhanced super-hydrophobic and switching behavior of ZnO nanostructured surfaces prepared by simple solution--immersion successive ionic layer adsorption and reaction process.

    PubMed

    Suresh Kumar, P; Sundaramurthy, J; Mangalaraj, D; Nataraj, D; Rajarathnam, D; Srinivasan, M P

    2011-11-01

    A simple and cost-effective successive ionic layer adsorption and reaction (SILAR) method was adopted to fabricate hydrophobic ZnO nanostructured surfaces on transparent indium-tin oxide (ITO), glass and polyethylene terephthalate (PET) substrates. ZnO films deposited on different substrates show hierarchical structures like spindle, flower and spherical shape with diameters ranging from 30 to 300 nm. The photo-induced switching behaviors of ZnO film surfaces between hydrophobic and hydrophilic states were examined by water contact angle and X-ray photoelectron spectroscopy (XPS) analysis. ZnO nanostructured films had contact angles of ~140° and 160°±2 on glass and PET substrates, respectively, exhibiting hydrophobic behavior without any surface modification or treatment. Upon exposure to ultraviolet (UV) illumination, the films showed hydrophilic behavior (contact angle: 15°±2), which upon low thermal stimuli revert back to its original hydrophobic nature. Such reversible and repeatable switching behaviors were observed upon cyclical exposure to ultraviolet radiation. These biomimetic ZnO surfaces exhibit good anti-reflective properties with lower reflectance of 9% for PET substrates. Thus, the present work is significant in terms of its potential application in switching devices, solar coatings and self-cleaning smart windows.

  8. Application of response surface methodology and artificial neural network: modeling and optimization of Cr(VI) adsorption process using Dowex 1X8 anion exchange resin.

    PubMed

    Harbi, Soumaya; Guesmi, Fatma; Tabassi, Dorra; Hannachi, Chiraz; Hamrouni, Bechir

    2016-01-01

    We report the adsorption efficiency of Cr(VI) on a strong anionic resin Dowex 1X8. The Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis of this adsorbent were investigated. Response surface methodology was applied to evaluate the main effects and interactions among initial pH, initial Cr(VI) concentration, adsorbent dose and temperature. Analysis of variance depicted that resin dose and initial pH were the most significant factors. Desirability function (DF) showed that the maximum Cr(VI) removal of 95.96% was obtained at initial pH 5, initial Cr(VI) concentration of 100 mg/L, resin dose of 2 g and temperature of 283 K. Additionally, a simulated industrial wastewater containing 14.95 mg/L of Cr(VI) was treated successfully by Dowex 1X8 at optimum conditions. Same experimental design was employed to develop the artificial neural network. Both models gave a high correlation coefficient (RRSM(2) = 0.932, RANN(2) = 0.996).

  9. Preparation of adsorbent with magnesium sulfate and straw pulp black liquor and its phenol adsorption properties

    NASA Astrophysics Data System (ADS)

    Guo, Lugang; Wang, Haizeng

    2009-09-01

    A magnesia adsorbent was prepared from straw pulp black liquor and magnesium sulfate for the first time, and its adsorption of phenol from aqueous solution was examined. The characteristics of the adsorbent were tested through chemical analysis, surface analysis, X-ray diffraction and FT-IR spectroscopy. The effects of various factors, such as dose, adsorption time and adsorption temperature, on phenol adsorption behavior were studied. The results show that the adsorption processes can be fitted to the isotherm Langmuir model very well. It was found that the adsorption process was strongly influenced by temperature and the optimal temperature for phenol removal was 40 °C. The optimum adsorption time was 10 min, and desorption would happen afterwards. Between the models of Langmuir and Freundlich, the adsorption process of phenol onto magnesia fitted the Langmuir equation better.

  10. Adsorption characteristics of brilliant green dye on kaolin.

    PubMed

    Nandi, B K; Goswami, A; Purkait, M K

    2009-01-15

    Experimental investigations were carried out to adsorb toxic brilliant green dye from aqueous medium using kaolin as an adsorbent. Characterization of kaolin is done by measuring: (i) particle size distribution using particle size analyzer, (ii) BET surface area using BET surface analyzer, and (iii) structural analysis using X-ray diffractometer. The effects of initial dye concentration, contact time, kaolin dose, stirring speed, pH and temperature were studied for the adsorption of brilliant green in batch mode. Adsorption experiments indicate that the extent of adsorption is strongly dependent on pH of solution. Free energy of adsorption (DeltaG0), enthalpy (DeltaH0) and entropy (DeltaS0) changes are calculated to know the nature of adsorption. The calculated values of DeltaG0 at 299K and 323K indicate that the adsorption process is spontaneous. The estimated values of DeltaH0 and DeltaS0 both show the negative sign, which indicate that the adsorption process is exothermic and the dye molecules are organized on the kaolin surface in less randomly fashion than in solution. The adsorption kinetic has been described by first-order, pseudo-second-order and intra-particle-diffusion models. It was observed that the rate of dye adsorption follows pseudo-second-order model for the dye concentration range studied in the present case. Standard adsorption isotherms were used to fit the experimental equilibrium data. It was found that the adsorption of brilliant green on kaolin follows the Langmuir adsorption isotherm.

  11. Adsorption and Exchange Kinetics of Hydrophilic and Hydrophobic Phosphorus Ligands on Gold Surface

    NASA Astrophysics Data System (ADS)

    Zhuge, X. Q.; Bian, Z. C.; Luo, Z. H.; Mu, Y. Y.; Luo, K.

    2017-02-01

    The adsorption kinetics process of hydrophobic ligand (triphenylphosphine, PPh3) and hydrophilic ligand (tris(hydroxymethyl)phosphine oxide, THPO) on the surface of gold electrode were estimated by using electrical double layer capacitance (EDLC). Results showed that the adsorption process of both ligands included fast and slow adsorption processes, and the fast adsorption process could fit the first order kinetic equation of Langmuir adsorption isotherm. During the slow adsorption process, the surface coverage (θ) of PPh3 was higher than that of THPO due to the larger adsorption kinetic constant of PPh3 than that of THPO, which implied that PPh3 could replace THPO on the gold electrode. The exchange process of both ligands on the surface of gold electrode proved that PPh3 take the place of THPO by testing the variation of EDLC which promote the preparation of Janus gold, and the theoretic simulation explained the reason of ligands exchange from the respect of energy..

  12. The study of adsorption characteristics of electrospun polymer nanofibers for benzenes in water.

    PubMed

    Sun, Jing; Kang, Xue-Jun; Ma, Yu-Qin; Chen, Li-Qin; Wang, Yu; Gu, Zhong-Ze

    2011-01-01

    The adsorption properties of benzene, p-dichlorobenzene and nitrobenzene on polymer nanofibers were studied. Compared with polyacrylonitrile nanofiber, polystyrene (PS) nanofiber presented better adsorption performance. Langmuir and Freundlich adsorption models were used for the mathematical description of adsorption equilibria, and Freundlich isotherms fitted better. Kinetic studies showed that the adsorption of PS nanofiber followed pseudo first-order model. Various thermodynamic parameters such as standard free energy (delta G), enthalpy (delta H) and entropy (delta S) were calculated for predicting the adsorption nature of PS nanofiber for three benzenes, which indicated that the adsorption was spontaneous and a physical process. The regeneration efficiency maintains over 80% after five cycles of adsorption/desorption tests. It showed that PS nanofibers are promising candidates for adsorption and removal of aromatic hydrocarbons from water.

  13. Adsorption of star polymers

    NASA Astrophysics Data System (ADS)

    Halperin, A.; Joanny, J. F.

    1991-06-01

    The adsorption of star polymers on a flat solid surface is analyzed by means of scalling arguments based on the Daoud-Cotton blob model. For the adsorption of a single star, consisting of f arms comprising each N monomers, we distinguish three regimes determined by the adsorption energy of a monomer at the surface, δ kT. 1) Strong adsorption characterized by the full adsorption of all arms occurs for δ > (f/N)^{3/5}. 2) A “Sombrero” like structure comprising f_ads fully adsorbed arms and f{-}f_ads free arms is obtained for (f/N)^{3/5}> δ > f^{9/20}/N^{3/5}. 3) Weakly adsorbed stars retain, essentially, the structure of a free star. This regime occurs for δ < f^{9/20}/N^{3/5}. The weakly adsorbed structure may also exist as a metastable state if δ > f^{9/5}/N^{3/5}. Nous étudions l'adsorption de polymères en étoile sur une surface solide en utilisant une approche de lois d'échelles basée sur le modèle de blobs de Daoud et Cotton. Pour une étoile formée de f bras contenant chacun N monomères, nous distinguons trois régimes suivant la valeur de l'énergie d'adsorption d'un monomère sur la surface δ kT. 1) L'adsorption forte caractérisée par une adsorption complète de tous les bras se produit lorsque δ > (f/N)^{3/5}. 2) Une structure en “sombrero” avec f_ads bras adsorbés et f{-}f_ads bras libres est obtenue si f^{9/20}/N^{3/5}δ < (f/N)^{3/5}. 3) Les étoiles faiblement adsorbées gardent une structure très similaire à celle des étoiles libres en solution. Ce régime existe si δ < f^{9/20}/N^{3/5}. La structure correspondant aux étoiles faiblement adsorbées peut aussi exister comme un état métastable si δ > f^{9/5}/N^{3/5}.

  14. Adsorption of Wine Constituents on Functionalized Surfaces.

    PubMed

    Mierczynska-Vasilev, Agnieszka; Smith, Paul A

    2016-10-18

    The adsorption of macromolecules on solid surfaces is of great importance in the field of nanotechnology, biomaterials, biotechnological, and food processes. In the field of oenology adsorption of wine macromolecules such as polyphenols, polysaccharides, and proteins is much less desirable on membrane materials because of fouling and reduced filtering performance. On the other hand, adsorption of these molecules on processing aids is very beneficial for achieving wine clarity and stability. In this article, the effect of surface chemical functionalities on the adsorption of white, rosé, and red wine constituents was evaluated. Allylamine, acrylic acid, and ethanol were selected as precursors for plasma polymerization in order to generate coatings rich in amine, carboxyl, and hydroxyl chemical groups, respectively. The surface chemical functionalities were characterized by X-ray photoelectron spectroscopy (XPS) and the ability of different surface chemical functionalities to adsorb wine constituents were characterized by quartz crystal microbalance with dissipation (QCM-D) and atomic force microscopy (AFM). The results demonstrated that the amine and carboxyl modified surfaces encourage adsorption of constituents from white wine. The hydroxyl modified surfaces have the ability to preferentially adsorb rosé wine constituents, whereas red wine adsorbed to the highest extent on acrylic acid surface.

  15. Equilibrium and kinetic adsorption study of the adsorptive removal of Cr(VI) using modified wheat residue.

    PubMed

    Chen, Suhong; Yue, Qinyan; Gao, Baoyu; Xu, Xing

    2010-09-01

    A new adsorbent modified from wheat residue was synthesized after reaction with epichlorohydrin and triethylamine by using the modifying agents of diethylenetriamine in the presence of organic medium of N,N-dimethylformamide. The performance of the modified wheat straw (MWS) was characterized by Fourier transform infrared spectroscopy and point of zero charge analysis. The adsorption was investigated in a batch adsorption system, including both equilibrium adsorption isotherms and kinetics. Results showed that MWR had great anion-adsorbing capacity, due to the existence of a large number of introduced amino groups, and the value of pH(PZC) was around 5.0. Equilibrium data were analyzed using the Langmuir, Freundlich, and Temkin isotherm models and were found to be best represented by the Freundlich isotherm model. Evaluation of the adsorption process identified its endothermic nature. The maximum adsorption capacity of MWS for the removal of Cr(VI) was 322.58mg/g at 328K, indicating that MWS has high chromium removal efficiency, compared to other adsorbents reported. The kinetics of adsorption followed the pseudo-second-order kinetic equation. The mechanism of adsorption was investigated using the intraparticle diffusion model. Thermodynamic parameters (free energy change, enthalpy change, and entropy change) revealed that the adsorption of Cr(VI) onto MWS was endothermic and spontaneous; additionally, the adsorption can be characterized as an ion-exchange process. The results suggest that MWS is an inexpensive and efficient adsorbent for removing Cr(VI) ions from aqueous solution.

  16. Adsorptive removal of 2-chlorophenol by low-cost coir pith carbon.

    PubMed

    Namasivayam, C; Kavitha, D

    2003-03-17

    Adsorption of 2-chlorophenol (2-CP) by coir pith carbon was carried out by varying the parameters such as agitation time, 2-CP concentration, adsorbent dose, pH and temperature. Adsorption equilibrium reached at 40, 60, 80 and 100 min for 2-CP concentration of 10, 20, 30 and 40 mg/l, respectively. Adsorption followed second-order kinetics. The adsorption equilibrium data obeyed Freundlich isotherm. Acidic pH was favorable for the adsorption of 2-CP. Desorption studies showed that chemisorption plays a major role in the adsorption process.

  17. Towards an accurate estimation of the isosteric heat of adsorption - A correlation with the potential theory.

    PubMed

    Askalany, Ahmed A; Saha, Bidyut B

    2017-03-15

    Accurate estimation of the isosteric heat of adsorption is mandatory for a good modeling of adsorption processes. In this paper a thermodynamic formalism on adsorbed phase volume which is a function of adsorption pressure and temperature has been proposed for the precise estimation of the isosteric heat of adsorption. The estimated isosteric heat of adsorption using the new correlation has been compared with measured values of prudently selected several adsorbent-refrigerant pairs from open literature. Results showed that the proposed isosteric heat of adsorption correlation fits the experimentally measured values better than the Clausius-Clapeyron equation.

  18. A Common Model to Handle PDS3 and PDS4 Data in the New Planetary Science Archive (PSA)

    NASA Astrophysics Data System (ADS)

    Macfarlane, A. J.; Barbarisi, I.; Rios, C.; Docasal, R.; Martinez, S.; Arviset, C.; Besse, S.; De Marchi, G.; Grotheer, E.; Gonzalez, J.; Lim, T.; Fraga, D.; Barthelemy, M.

    2015-12-01

    The first of the European Space Agency's (ESA) planetary missions to make use of the latest release of the Planetary Data Standards (PDS4) are currently in advanced stages of development (ExoMars, BepiColombo). This occurs at a time when the Planetary Science Archive (PSA) has been undergoing a complete reengineering in order to increase the accessibility of ESA's planetary data holdings utilising the latest technologies and to significantly improve the user experience for both the specialist scientific community and general public alike. The PSA must also keep on handling PDS3 data arriving to the archive from active missions (Rosetta, Mars Express, Venus Express) as well as continuing to provide access to missions that have reached the legacy phase (Huygens, SMART1, Giotto). Therefore, as part of the reengineering of the PSA, an effort has been made to map the key metadata from PDS3 and PDS4 into a common data model with the intention of providing transparency to the services that make up the new PSA, and consequently to the end user. We present how this common mapping allows the PSA to support the data deliveries from the pipelines of existing missions without the need to reprocess the PDS3 data and in addition how it should simplify the data deliveries from PDS4 missions. We review how the implementation of this data model, involving a PostgreSQL database with the PostGIS extension, enables the new PSA to be able to provide multiple methods of interoperability used by the international community, such as PDAP (Planetary Data Access Protocol), EPN-TAP (EuroPlanet-Table Access Protocol), and GIS-enabled technologies without the user having to know in detail the underlying structure of the data format.

  19. Assessing the Adsorption Properties of Shales

    NASA Astrophysics Data System (ADS)

    Pini, R.

    2014-12-01

    Fine-grained rocks, such as shales, contain a significant amount of nanopores that can significantly contribute to their storage capacity through the mechanism of adsorption. The current ability to extract natural gas that is adsorbed in the rock's matrix is limited and current technology focuses primarily on the free gas in the fractures, thus leading to very low recovery efficiencies. Shales constitute also a great portion of so-called caprocks above potential CO2 sequestration sites; hereby, the adsorption process may limit the CO2 mobility within the cap-rock, thus minimizing leakage phenomena. Whether it is a reservoir or a caprock, understanding and quantifying the mechanisms of adsorption in these natural materials is key to improve the engineering design of subsurface operations. Results will be presented from a laboratory study that combines conventional techniques for the measurement of adsorption isotherms with novel methods that allows for the imaging of adsorption using x-rays. Various nanoporous materials are considered, thus including rocks, such as shales and coals, pure clay minerals and engineered adsorbents with well-defined nanopore structures, such as zeolites. Supercritical CO2 adsorption isotherms have been measured with a Rubotherm Magnetic Suspension balance by covering the pressure range 0.1-20~MPa. A medical x-ray CT scanner has been used to identify three-dimensional patterns of the adsorption properties of a packed-bed of adsorbent, thus enabling to assess the spatial variability of the adsorption isotherm. The data are analyzed by using thermodynamically rigorous measures of adsorption and a graphical method is applied for their interpretation. The density of the adsorbed phase is estimated and compared to data reported in the literature; the latter is key to disclose gas-reserves and/or potential storage capacity estimates. When evaluated against classic adsorbent materials, the adsorption mechanism in shales is further complicated by

  20. pH6 antigen (PsaA protein) of Yersinia pestis, a novel bacterial Fc-receptor.

    PubMed

    Zav'yalov, V P; Abramov, V M; Cherepanov, P G; Spirina, G V; Chernovskaya, T V; Vasiliev, A M; Zav'yalova, G A

    1996-05-01

    It was found that recombinant pH6 antigen (rPsaA protein) forming virulence-associated fimbriae on the surface of Yersinia pestis at pH 6.7 in host macrophage phagolysosomes or extracellularly in abscesses such as buboes, is a novel bacterial Fc-receptor. rPsaA protein displays reactivity with human IgG1, IgG2 and IgG3 subclasses but does not react with rabbit, mouse and sheep IgG.

  1. Adsorption of Pyrene onto the Agricultural By-Product: Corncob.

    PubMed

    Li, Xiaojun; Tong, Dongli; Allinson, Graeme; Jia, Chunyun; Gong, Zongqing; Liu, Wan

    2016-01-01

    The adsorption behavior of pyrene on corncob was studied to provide a theoretical basis for the possible use of this material as an immobilized carrier for improving the bioremediation of PAH-contaminated soil. The results were as follows. Kinetic experiments showed that the adsorption processes obeyed a pseudo-second-order model. The intraparticle diffusion of Weber-Morris model fitting showed that the film and intraparticle diffusions were the key rate-limiting processes, and the adsorption process mainly consisted of three steps: boundary layer diffusion and two intra-particle diffusions. Experimental adsorption data for pyrene were successfully described by the adsorption-partition equilibrium model. The maximum adsorption capacity at 25°C was 214.8 μg g(-1). The adsorption contribution decreased significantly when the Ce/Sw (the equilibrium concentration/solubility in water) was higher than 1. Adsorption decreased with increased temperature. Based on the above results, the corncob particles could be helpful in the bioremediation of pyrene-contaminated soil.

  2. Somatic mutations throughout the entire mitochondrial genome are associated with elevated PSA levels in prostate cancer patients.

    PubMed

    Kloss-Brandstätter, Anita; Schäfer, Georg; Erhart, Gertraud; Hüttenhofer, Alexander; Coassin, Stefan; Seifarth, Christof; Summerer, Monika; Bektic, Jasmin; Klocker, Helmut; Kronenberg, Florian

    2010-12-10

    The genetic etiology of prostate cancer, the most common form of male cancer in western countries, is complex and the interplay of disease genes with environmental factors is far from being understood. Studies on somatic mitochondrial DNA (mtDNA) mutations have become an important aspect of cancer research because these mutations might have functional consequences and/or might serve as biosensors for tumor detection and progression. We sequenced the entire mitochondrial genome (16,569 bp) from 30 prospectively collected pairs of macrodissected cancerous and benign cells from prostate cancer patients and compared their genetic variability. Given recent concerns regarding the authenticity of newly discovered mtDNA mutations, we implemented a high-quality procedure for mtDNA whole-genome sequencing. In addition, the mitochondrial genes MT-CO2, MT-CO3, MT-ATP6, and MT-ND6 were sequenced in further 35 paired samples from prostate cancer patients. We identified a total of 41 somatic mutations in 22 out of 30 patients: the majority of these mutations have not previously been observed in the human phylogeny. The presence of somatic mutations in transfer RNAs (tRNAs) was found to be associated with elevated PSA levels (14.25 ± 5.44 versus 7.15 ± 4.32 ng/ml; p = 0.004). The level and degree of heteroplasmy increased with increasing tumor activity. In summary, somatic mutations in the mitochondrial genome are frequent events in prostate cancer. Mutations mapping to mitochondrial tRNAs, ribosomal RNAs, and protein coding genes might impair processes that occur within the mitochondrial compartment (e.g., transcription, RNA processing, and translation) and might finally affect oxidative phosphorylation.

  3. Somatic Mutations throughout the Entire Mitochondrial Genome Are Associated with Elevated PSA Levels in Prostate Cancer Patients

    PubMed Central

    Kloss-Brandstätter, Anita; Schäfer, Georg; Erhart, Gertraud; Hüttenhofer, Alexander; Coassin, Stefan; Seifarth, Christof; Summerer, Monika; Bektic, Jasmin; Klocker, Helmut; Kronenberg, Florian

    2010-01-01

    The genetic etiology of prostate cancer, the most common form of male cancer in western countries, is complex and the interplay of disease genes with environmental factors is far from being understood. Studies on somatic mitochondrial DNA (mtDNA) mutations have become an important aspect of cancer research because these mutations might have functional consequences and/or might serve as biosensors for tumor detection and progression. We sequenced the entire mitochondrial genome (16,569 bp) from 30 prospectively collected pairs of macrodissected cancerous and benign cells from prostate cancer patients and compared their genetic variability. Given recent concerns regarding the authenticity of newly discovered mtDNA mutations, we implemented a high-quality procedure for mtDNA whole-genome sequencing. In addition, the mitochondrial genes MT-CO2, MT-CO3, MT-ATP6, and MT-ND6 were sequenced in further 35 paired samples from prostate cancer patients. We identified a total of 41 somatic mutations in 22 out of 30 patients: the majority of these mutations have not previously been observed in the human phylogeny. The presence of somatic mutations in transfer RNAs (tRNAs) was found to be associated with elevated PSA levels (14.25 ± 5.44 versus 7.15 ± 4.32 ng/ml; p = 0.004). The level and degree of heteroplasmy increased with increasing tumor activity. In summary, somatic mutations in the mitochondrial genome are frequent events in prostate cancer. Mutations mapping to mitochondrial tRNAs, ribosomal RNAs, and protein coding genes might impair processes that occur within the mitochondrial compartment (e.g., transcription, RNA processing, and translation) and might finally affect oxidative phosphorylation. PMID:21129724

  4. Effective surface areas of coals measured by dye adsorption

    SciTech Connect

    Spitzer, D.P.

    1988-01-01

    The primary interest has been to examine adsorption behavior especially at short contact times, ten minutes to an hour, to determine whether such measurements might give useful data on effective surface areas - i.e., the surface that would be accessible to reagents within times comparable to those typical of most coal processing. Accordingly, most of the emphasis is on the effect of time on adsorption, rather than on traditional adsorption isotherms. Although most literature on cationic dye adsorption (mostly on carbons) uses methylene blue, it happened that the authors originally used safranin O instead because this dye was reported to be useful in distinguishing oxidized coals from fresh coals. Many of their experiments were repeated using methylene blue (in water), with very similar results. It was noted early that swelling of coals in water was common, especially for more oxidized or lower rank coals, and adsorption experiments were also done in another solvent, namely methanol. This produced quite striking differences for some coals. Coal surfaces that are readily accessible to adsorption by safranin are found to correlate well with N/sub 2/ surface areas, with adsorption of 1.0 mg safranin per gram of coal corresponding to essentially a surface area of 1.0 m/sup 2//g. Highly oxidized coals were found to swell considerably in water, with correspondingly increased adsorption. Areas of such coals can be estimated by adsorption of safranin from methanol solutions.

  5. Neptunium(V) adsorption to calcite.

    PubMed

    Heberling, Frank; Brendebach, Boris; Bosbach, Dirk

    2008-12-12

    The migration behavior of the actinyl ions U(VI)O2(2+), Np(V)O2+ and Pu(V,VI)O2(+,2+) in the geosphere is to a large extend controlled by sorption reactions (inner- or outer-sphere adsorption, ion-exchange, coprecipitation/structural incorporation) with minerals. Here NpO2+ adsorption onto calcite is studied in batch type experiments over a wide range of pH (6.0-9.4) and concentration (0.4 microM-40 microM) conditions. pH is adjusted by variation of CO2 partial pressure. Adsorption is found to be pH dependent with maximal adsorption at pH 8.3 decreasing with increasing and decreasing pH. pH dependence of adsorption decreases with increasing Np(V) concentration. EXAFS data of neptunyl adsorbed to calcite and neptunyl in the supernatant shows differences in the Np(V)-O-yl distance, 1.85+/-0.01 angstroms for the adsorbed and 1.82+/-0.01 angstroms for the solution species. The equatorial environment of the neptunyl in solution shows about 5 oxygen neighbours at 2.45+/-0.02 angstroms. For adsorbed neptunyl there are also about 5 oxygen neighbours at 2.46+/-0.01 angstroms. An additional feature in the adsorbed species' R-space spectrum can be related to carbonate neighbours, 3 to 6 carbon backscatterers (C-eq) at 3.05+/-0.03 angstroms and 3 to 6 oxygen backscatterers (O-eq2) at 3.31+/-0.02 angstroms. The differences in the Np(V)-O-yl distance and the C-eq and O-eq2 backscatterers which are only present for the adsorbed species indicate inner-sphere bonding of the adsorbed neptunyl species to the calcite surface. Experiments on adsorption kinetics indicate that after a fast surface adsorption process a continuous slow uptake occurs which may be explained by incorporation via surface dissolution and reprecipitation processes. This is also indicated by the part irreversibility of the adsorption as shown by increased KD values after desorption compared to adsorption.

  6. Study of Methylene Blue adsorption on keratin nanofibrous membranes.

    PubMed

    Aluigi, A; Rombaldoni, F; Tonetti, C; Jannoke, L

    2014-03-15

    In this work, keratin nanofibrous membranes (mean diameter of about 220nm) were prepared by electrospinning and tested as adsorbents for Methylene Blue through batch adsorption tests. The adsorption capacity of the membranes was evaluated as a function of initial dye concentration, pH, adsorbent dosage, time and temperature. The adsorption capacity increased with increasing the initial dye concentration and pH, while it decreased with increasing the adsorbent dosage and temperature, indicating an exothermic process. The adsorption results indicated that the Langmuir isotherm fitted the experimental data better than the Freundlich and Temkin isotherm models. A mean free energy evaluated through the Dubinin-Radushkevich model of about 16kJmol(-1), indicated a chemisorption process which occurred by ion exchange. The kinetic data were found to fit the pseudo-second-order model better than the pseudo-first-order model. The obtained results suggest that keratin nanofibrous membranes could be promising candidates as dye adsorption filters.

  7. Reuse of Solid Waste in Adsorption of the Textile Dye

    NASA Astrophysics Data System (ADS)

    Meziti, Chafika; Boukerroui, Abdelhamid

    This work presents the study of the reuse of a regenerated spent bleaching earth (RSBE). The RSBE material was tested in the removal of a basic textile dye presents in aqueous solution. The effect of physicochemical parameters such as stirring speed, initial concentration, contact time and temperature have been invested and thermodynamic nature of the adsorption process was determined by calculating the ΔH°, ΔS° and ΔG° values The results obtained show that the adsorption mechanism was described by the Langmuir model and the adsorption capacity, qmax (72.41 to 82.37 mg.g-1), increases with temperature (20-50 °C). The thermodynamic parameters show a presence of a strong affinity between two phases (liquid-solid) and an endothermic equilibrium adsorption process. However, the phenomenon of the adsorption kinetic follows the pseudo second order kinetic model.

  8. Preparation and properties of ion-imprinted hollow particles for the selective adsorption of silver ions.

    PubMed

    Hou, Hongbin; Yu, Demei; Hu, Guohe

    2015-02-03

    Four kinds of silver ion-imprinted particles (Ag-IIPs) with different morphologies were prepared by the surface ion-imprinting technology (SIIT) and were used for the selective removal and concentration of silver ions from wastewater. The favorable adsorptivity and selectivity of Ag-IIPs for Ag(+) were confirmed by a series of adsorption experiments at a suitable pH value. The adsorption mechanism was elucidated by analyzing the adsorption isotherms, adsorption thermodynamics, and adsorption kinetics systematically. The Ag(+) adsorption onto the Ag-IIPs was well-described by the Langmuir isotherm model, and it was likely to be a monolayer chemical adsorption. This conclusion was also confirmed by the thermodynamic parameters. Moreover, the adsorption kinetics indicated that the adsorption rate would be controlled jointly by the intraparticle diffusion and the inner surface adsorption process, and the latter process was generally associated with the formation and breaking of chemical bonds. Finally, the effects of different morphologies of the Ag-IIPs for Ag(+) adsorption were also investigated. In aqueous solution, the adsorptivity of the Ag(+) ion-imprinting single-hole hollow particles (Ag-IISHPs) for Ag(+) was highest (80.5 mg g(-1)) because of a specific morphology that features a single hole in the shell. In an oil-water mixture, Ag(+) in the water phase could be adsorbed efficiently by the Ag(+) ion-imprinting Janus hollow particles (Ag-IIJHPs), with emulsifiability originating from the Janus structure.

  9. Adsorption efficiency of natural materials for low-concentration cesium in solution.

    PubMed

    Miura, A; Kubota, T; Hamada, K; Hitomi, T

    2016-01-01

    In this study, several natural materials were investigated in order to clarify their potential use as cesium (Cs) adsorbents in situ. Four materials--carbonized rice hull, beech sawdust, oak sawdust, and charcoal (Japanese cedar)--which were previously shown to have Cs adsorption capabilities, were examined. Cs adsorption experiments were conducted using different initial Cs and adsorbent concentrations. The physical properties, adsorption isotherms, and adsorption processes were then examined, so as to exploit the Cs adsorption characteristics in the field. Based on these findings, carbonized rice hull and beech sawdust were selected as effective Cs adsorbents. It was found that these materials show continuous and stable Cs adsorption rates for different initial Cs concentrations. The adsorption efficiency of these two adsorption materials in combination was considered, and it was shown that the adsorption isotherms for carbonized rice hull and beech sawdust follow the Freundlich model. Furthermore, the beech sawdust adsorption process exhibited better agreement with the calculated values obtained via the adsorption rate model and the adsorption kinetics model than did the carbonized rice hull adsorption.

  10. Adsorption behavior of heavy metals on biomaterials.

    PubMed

    Minamisawa, Mayumi; Minamisawa, Hiroaki; Yoshida, Shoichiro; Takai, Nobuharu

    2004-09-08

    We have investigated adsorption of Cd(II) and Pb(II) at pH 2-6.7 onto the biomaterials chitosan, coffee, green tea, tea, yuzu, aloe, and Japanese coarse tea, and onto the inorganic adsorbents, activated carbon and zeolite. High adsorptive capabilities were observed for all of the biomaterials at pH 4 and 6.7. In the adsorption of Cd(II), blend coffee, tea, green tea, and coarse tea have comparable loading capacities to activated carbon and zeolite. Although activated carbon, zeolite, and chitosan are utilized in a variety of fields such as wastewater treatment, chemical and metallurgical engineering, and analytical chemistry, these adsorbents are costly. On the other hand, processing of the test biomaterials was inexpensive, and all the biomaterials except for chitosan were able to adsorb large amounts of Pb(II) and Cd(II) ions after a convenient pretreatment of washing with water followed by drying. The high adsorption capability of the biomaterials prepared from plant materials is promising in the development of a novel, low-cost adsorbent. From these results, it is concluded that heavy metal removal using biomaterials would be an effective method for the economic treatment of wastewater. The proposed adsorption method was applied to the determination of amounts of Cd(II) and Pb(II) in water samples.

  11. Adsorption of phenanthrene on natural snow.

    PubMed

    Domine, Florent; Cincinelli, Alessandra; Bonnaud, Elodie; Martellini, Tania; Picaud, Sylvain

    2007-09-01

    The snowpack is a reservoir for semivolatile organic compounds (SVOCs) and, in particular, for persistent organic pollutants (POPs), which are sequestered in winter and released to the atmosphere or hydrosphere in the spring. Modeling these processes usually assumes that SVOCs are incorporated into the snowpack by adsorption to snow surfaces, but this has never been proven because the specific surface area (SSA) of snow has never been measured together with snow composition. Here we expose natural snow to phenanthrene vapors (one of the more volatile POPs) and measure for the first time both the SSA and the chemical composition of the snow. The results are consistent with an adsorption equilibrium. The measured Henry's law constant is H(Phen)(T) = 2.88 x 10(22) exp(-10660/7) Pa m2 mol(-1), with Tin Kelvin. The adsorption enthalpy is delta H(ads) = -89 +/- 18 kJ mol(-1). We also perform molecular dynamics calculations of phenanthrene adsorption to ice and obtain AHads = -85 +/- 8 kJ mol(-1), close to the experimental value. Results are applied to the adsorption of phenanthrene to the Arctic and subarctic snowpacks. The subarctic snowpack, with a low snow area index (SAI = 1000), is a negligible reservoir of phenanthrene, butthe colder Arctic snowpack, with SAI = 2500, sequesters most of the phenanthrene present in the (snow + boundary layer) system.

  12. Doctors' perspectives on PSA testing illuminate established differences in prostate cancer screening rates between Australia and the UK: a qualitative study

    PubMed Central

    Pickles, Kristen; Carter, Stacy M; Rychetnik, Lucie; Entwistle, Vikki A

    2016-01-01

    Objectives To examine how general practitioners (GPs) in the UK and GPs in Australia explain their prostate-specific antigen (PSA) testing practices and to illuminate how these explanations are similar and how they are different. Design A grounded theory study. Setting Primary care practices in Australia and the UK. Participants 69 GPs in Australia (n=40) and the UK (n=29). We included GPs of varying ages, sex, clinical experience and patient populations. All GPs interested in participating in the study were included. Results GPs' accounts revealed fundamental differences in whether and how prostate cancer screening occurred in their practice and in the broader context within which they operate. The history of prostate screening policy, organisational structures and funding models appeared to drive more prostate screening in Australia and less in the UK. In Australia, screening processes and decisions were mostly at the discretion of individual clinicians, and varied considerably, whereas the accounts of UK GPs clearly reflected a consistent, organisationally embedded approach based on local evidence-based recommendations to discourage screening. Conclusions The GP accounts suggested that healthcare systems, including historical and current organisational and funding structures and rules, collectively contribute to how and why clinicians use the PSA test and play a significant role in creating the mindlines that GPs employ in their clinic. Australia's recently released consensus guidelines may support more streamlined and consistent care. However, if GP mindlines and thus routine practice in Australia are to shift, to ultimately reduce unnecessary or harmful prostate screening, it is likely that other important drivers at all levels of the screening process will need to be addressed. PMID:27920082

  13. Functionalized mesoporous silica materials for molsidomine adsorption: Thermodynamic study

    SciTech Connect

    Alyoshina, Nonna A.; Parfenyuk, Elena V.

    2013-09-15

    A series of unmodified and organically modified mesoporous silica materials was prepared. The unmodified mesoporous silica was synthesized via sol–gel synthesis in the presence of D-glucose as pore-forming agent. The functionalized by phenyl, aminopropyl and mercaptopropyl groups silica materials were prepared via grafting. The fabricated adsorbent materials were characterized by Fourier transform infrared spectroscopy (FTIR) analysis, N{sub 2} adsorption/desorption and elemental analysis methods. Then their adsorption properties for mesoionic dug molsidomine were investigated at 290–313 K and physiological pH value. Thermodynamic parameters of molsidomine adsorption on the synthesized materials have been calculated. The obtained results showed that the adsorption process of molsidomine on the phenyl modified silica is the most quantitatively and energetically favorable. The unmodified and mercaptopropyl modified silica materials exhibit significantly higher adsorption capacities and energies for molsidomine than the aminopropyl modified sample. The effects are discussed from the viewpoint of nature of specific interactions responsible for the adsorption. - Graphical abstract: Comparative analysis of the thermodynamic characteristics of molsidomine adsorption showed that the adsorption process on mesoporous silica materials is controlled by chemical nature of surface functional groups. Molsidomine adsorption on the phenyl modified silica is the most quantitatively and energetically favorable. Taking into account ambiguous nature of mesoionic compounds, it was found that molsidomine is rather aromatic than dipolar. Display Omitted - Highlights: • Unmodified and organically modified mesoporous silica materials were prepared. • Molsidomine adsorption on the silica materials was studied. • Phenyl modified silica shows the highest adsorption capacity and favorable energy. • Molsidomine exhibits the lowest affinity to aminopropyl modified silica.

  14. Cotton cellulose: enzyme adsorption and enzymic hydrolysis

    SciTech Connect

    Beltrame, P.L.; Carniti, P.; Focher, B.; Marzetti, A.; Cattaneo, M.

    1982-01-01

    The adsorption of a crude cellulase complex from Trichoderma viride on variously pretreated cotton cellulose samples was studied in the framework of the Langmuir approach at 2-8 degrees. The saturation amount of adsorbed enzyme was related to the susceptibility of the substrates to hydrolysis. In every case the adsorption process was faster by 2-3 orders of magnitude than the hydrolysis step to give end products. For ZnCl/sub 2/-treated cotton cellulose the Langmuir parameters correlated fairly well with the value of the Michaelis constant, measured for its enzymic hydrolysis, and the adsorptive complex was indistinguishable from the complex of the Michaelis-Menten model for the hydrolysis.

  15. Adsorption of monoclonal antibodies to glass microparticles.

    PubMed

    Hoehne, Matthew; Samuel, Fauna; Dong, Aichun; Wurth, Christine; Mahler, Hanns-Christian; Carpenter, John F; Randolph, Theodore W

    2011-01-01

    Microparticulate glass represents a potential contamination to protein formulations that may occur as a result of processing conditions or glass types. The effect of added microparticulate glass to formulations of three humanized antibodies was tested. Under the three formulation conditions tested, all three antibodies adsorbed irreversibly at near monolayer surface coverages to the glass microparticles. Analysis of the secondary structure of the adsorbed antibodies by infrared spectroscopy reveal only minor perturbations as a result of adsorption. Likewise, front-face fluorescence quenching measurements reflected minimal tertiary structural changes upon adsorption. In contrast to the minimal effects on protein structure, adsorption of protein to suspensions of glass microparticles induced significant colloidal destabilization and flocculation of the suspension.

  16. New Adsorption Methods.

    ERIC Educational Resources Information Center

    Wankat, Phillip C.

    1984-01-01

    Discusses a simple method for following the movement of a solute in an adsorption or ion exchange system. This movement is used to study a variety of operational methods, including continuous flow and pulsed flow counter-current operations and simulated counter-current systems. Effect of changing thermodynamic variables is also considered. (JM)

  17. SEPARATION BY ADSORPTION

    DOEpatents

    Lowe, C.S.

    1959-06-16

    Separation of Pu from fission products by adsorption on hydrous aluminum silicate is described. The Pu in a HNO/sub 3/ solution is oxidized to the hexavalent state and contacted with the silicate which adsorbs fission products. (T.R.H.)

  18. Kinetics of phosphate adsorption on goethite: comparing batch adsorption and ATR-IR measurements.

    PubMed

    Luengo, Carina; Brigante, Maximiliano; Antelo, Juan; Avena, Marcelo

    2006-08-15

    The adsorption kinetics of phosphate on goethite has been studied by batch adsorption experiments and by in situ ATR-IR spectroscopy at different pH, initial phosphate concentrations and stirring rates. Batch adsorption results are very similar to those reported by several authors, and show a rather fast initial adsorption taking place in a few minutes followed by a slower process taking place in days or weeks. The adsorption kinetics could be also monitored by integrating the phosphate signals obtained in ATR-IR experiments, and a very good agreement between both techniques was found. At pH 4.5 two surface complexes, the bidentate nonprotonated (FeO)(2)PO(2) and the bidentate protonated (FeO)(2)(OH)PO complexes, are formed at the surface. There are small changes in the relative concentrations of these species as the reaction proceeds, and they seem to evolve in time rather independently. At pH 7.5 and 9 the dominating surface species is (FeO)(2)PO(2), which is accompanied by an extra unidentified species at low concentration. They also seem to evolve independently as the reaction proceeds. The results are consistent with a mechanism that involve a fast adsorption followed by a slow diffusion into pores, and are not consistent with surface precipitation of iron phosphate.

  19. Adsorption of alkyltrimethylammonium bromides at water/alkane interfaces: competitive adsorption of alkanes and surfactants.

    PubMed

    Fainerman, V B; Mucic, N; Pradines, V; Aksenenko, E V; Miller, R

    2013-11-12

    The adsorption of members of the homologous series of alkyl trimethylammonium bromides (C(n)TAB) is studied at water/alkane interfaces by drop profile analysis tensiometry. The results are discussed in terms of a competitive adsorption process of alkane and surfactant molecules. A thermodynamic model, derived originally for the adsorption of surfactant mixtures, is adapted such that it describes a competitive adsorption of the surfactant molecules from the aqueous phase and alkane molecules from the oil phase. This new model involves the interspecies attraction coefficient, which mutually increases the adsorption activities of the alkane and C(n)TAB. The effects of the alkyl chain length n of C(n)TABs and the influence of the number of C atoms in the alkane chain are discussed, and the physical quantities are compared to those determined at the aqueous solution/air interface. The new theoretical model for aqueous solution/oil interfaces is also compared to a theory that does not consider the adsorption of alkane. The proposed new model demonstrates good agreement with the experimental data.

  20. Adsorption of ammonium dinitramide (ADN) from aqueous solutions. 1. Adsorption on powdered activated charcoal.

    PubMed

    Santhosh, G; Venkatachalam, S; Ninan, K N; Sadhana, R; Alwan, S; Abarna, V; Joseph, M A

    2003-03-17

    Investigations on the adsorption of ammonium dinitramide (NH(4)N(NO(2))(2)) (ADN) from aqueous solutions on powdered activated charcoal (PAC) were carried out in order to find out an effective and easier method of separating ADN from aqueous solutions. The effectiveness of PAC in the selective adsorption of ADN from aqueous solutions of ADN (ADN-F) and ADN in presence of sulfate (SO(4)(2-)) and nitrate (NO(3)(-)) ions (ADN-PS) was examined and compared using batch and column methods. The adsorption process follows both Langmuir and Freundlich adsorption isotherms and the isotherm parameters for the models were determined. The observed data favor the formation of monolayer adsorption. The adsorption capacities were found to be 63.3, 119, 105.3 and 82 mg of ADN per g of PAC for ADN-F (batch), ADN-PS (batch), ADN-F (column) and ADN-PS (column), respectively. Break-through curves for ADN-F and ADN-PS were obtained for the optimization of separation of ADN from aqueous solutions. Elution curves were generated for the desorption of ADN from PAC using hot water as eluent.

  1. Adsorptive removal of PPCPs by biomorphic HAP templated from cotton.

    PubMed

    Huang, Bin; Xiong, Dan; Zhao, Tingting; He, Huan; Pan, Xuejun

    2016-01-01

    Biomorphic nano-hydroxyapatite (HAP) was fabricated by a co-precipitation method using cotton as bio-templates and employed in adsorptive removal of ofloxacin (OFL) and triclosan (TCS) that are two representative pharmaceuticals and personal care products (PPCPs). The surface area and porosity, crystal phase, functional group, morphology and micro-structure of the synthesized HAP were characterized by Brunauer-Emmett-Teller isotherm, X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron macroscopic and transmission electron microscopy. The effects of initial pH, ionic strength, initial concentration, contact time and temperature on the removal of PPCPs were studied in a batch experiment. The adsorption of OFL and TCS was rapid and almost accomplished within 50 min. Kinetic studies indicated that the adsorption process of OFL and TCS followed the pseudo-first-order and pseudo-second-order models, respectively. The Freundlich isotherm described the OFL adsorption process well but the adsorption of TCS fitted the Langmuir isotherm better. Thermodynamics and isotherm parameters suggested that both OFL and TCS adsorption were feasible and spontaneous. Hydrogen bond and Lewis acid-base reaction may be the dominating adsorption mechanism of OFL and TCS, respectively. Compared to other adsorbents, biomorphic HAP is environmentally friendly and has the advantages of high adsorption capacity, exhibiting potential application for PPCPs removal.

  2. Performance characteristics and relationship of PSA value/kinetics on carbon-11 acetate PET/CT imaging in biochemical relapse of prostate cancer

    PubMed Central

    Almeida, Fabio D; Yen, Chi-Kwan; Scholz, Mark C; Lam, Richard Y; Turner, Jeffrey; Bans, Larry L; Lipson, Robert

    2017-01-01

    An elevated serum prostate-specific antigen (PSA) level alone cannot distinguish between local-regional recurrences and distant metastases after treatment with curative intent. With available salvage treatments, it has become important to localize the site of recurrence. 11C-Acetate PET/CT was performed in patients with rising PSA, with statistical analysis of detection rates, sites/location of detection, PSA kinetics and comparison with other tracers (FDG and Choline). Correlation to biopsy, subsequent imaging and PSA response to focal treatment was also performed. 88% (637) of 721 11C-Acetate PET/CT scans performed were positive. There was a statistically significant difference in PSA values between the positive and negative scans (P < 0.001 for mean difference) with the percentage of positive scans and PSA having a positive correlation. A PSA of 1.09 ng/mL was found to be an optimal cutoff. PSAdT was significantly correlated with a positive scan only when the PSA was < 1.0 ng/mL. For this subgroup, a PSAdT of < 3.8 months appeared significant (P < 0.05) as an optimal cutoff point. 11C-Acetate PET/CT demonstrates a high detection rate for the site of recurrence/metastasis in biochemical relapsed prostate cancer (88% overall detection rate, PPV 90.8%). This analysis suggests an optimal PSA threshold of > 1.09 ng/mL or a PSAdT of < 3.8 months when the PSA is below 1.0 ng/mL as independent predictors of positive findings. PMID:28123863

  3. Plasma Carotenoids and Tocopherols in Relation to Prostate-specific Antigen (PSA) Levels Among Men with Biochemical Recurrence of Prostate Cancer

    PubMed Central

    Antwi, Samuel; Steck, Susan E.; Zhang, Hongmei; Stumm, Lareissa; Zhang, Jiajia; Hurley, Thomas G.; Hebert, James R.

    2015-01-01

    Background Although men presenting with clinically localized prostate cancer (PrCA) often are treated with radical prostatectomy or radiation therapy with curative intent, about 25–40% develop biochemically recurrent PrCA within 5 years of treatment, which has no known cure. Studies suggest that carotenoid and tocopherol intake may be associated with PrCA risk and progression. We examined plasma carotenoid and tocopherol levels in relation to prostate-specific antigen (PSA) levels among men with PSA-defined biochemical recurrence of PrCA. Methods Data analyzed were from a 6-month diet, physical activity and stress-reduction intervention trial conducted in South Carolina among biochemically recurrent PrCA patients (n=39). Plasma carotenoids and tocopherol levels were measured using high-performance liquid chromatography (HPLC). Linear regression was used to estimate least-square means comparing PSA levels of men with high versus low carotenoid/tocopherol levels, adjusting for covariates. Results After adjusting for baseline PSA level, plasma cis-lutein/zeaxanthin level at 3 months was related inversely to PSA level at 3 months (P=0.0008), while α-tocopherol (P=0.01), β-cryptoxanthin (P=0.01), and all-trans-lycopene (P=0.004) levels at 3 months were related inversely to PSA levels at 6-months. Percent increase in α-tocopherol and trans-β-carotene levels from baseline to month 3 were associated with lower PSA levels at 3 and 6 months. Percent increase in β−cryptoxanthin, cislutein/zeaxanthin and all-trans-lycopene were associated with lower PSA levels at 6 months only. Conclusions Certain plasma carotenoids and tocopherols were related inversely to PSA levels at various timepoints, suggesting that greater intake of foods containing these micronutrients might be beneficial to men with PSA-defined PrCA recurrence. PMID:26165176

  4. The effects of autohydrolysis pretreatment on the structural characteristics, adsorptive and catalytic properties of the activated carbon prepared from Eucommia ulmoides Oliver based on a biorefinery process.

    PubMed

    Zhu, Ming-Qiang; Wang, Zhi-Wen; Wen, Jia-Long; Qiu, Ling; Zhu, Ya-Hong; Su, Yin-Quan; Wei, Qin; Sun, Run-Cang

    2017-05-01

    Eucommia ulmoides Oliver (EU) wood was consecutively treated by autohydrolysis pretreatment and chemical carbonization post-treatment based on a biorefinery process. Results showed that the optimal condition of the autohydrolysis pretreatment and carbonization process yielded 10.37kg xylooligosaccharides (XOS), 1.39kg degraded hemicellulosic products, 17.29kg other degraded products from hemicelluloses and 40.72kg activated carbon (SBET of 1534.06m(2)/g) from the 100kg raw materials. Simultaneously, 29.14kg gas products generated from the optimum integrated process was significantly lower than that from the direct carbonization process (68.84kg). Besides, the optimal activated carbon (AC170-1.0) also showed a moderate catalytic activity and high stability for hydrogen production by catalytic methane decomposition. Overall, the data presented indicated that the integrated process is an eco-friendly and efficient process to produce XOS and activated carbon, which is beneficial for value-added and industrial application of EU wood.

  5. Enhanced immunogenicity of pneumococcal surface adhesin A (PsaA) in mice via fusion to recombinant human B lymphocyte stimulator (BLyS)

    PubMed Central

    2011-01-01

    Background B lymphocyte stimulator (BLyS) is a member of the tumor necrosis factor superfamily of ligands that mediates its action through three known receptors. BLyS has been shown to enhance the production of antibodies against heterologous antigens when present at elevated concentrations, supporting an immunostimulatory role for BLyS in vivo. Methods We constructed a fusion protein consisting of human BLyS and Pneumococcal Surface Adhesin A (PsaA) and used this molecule to immunize mice. The immunostimulatory attributes mediated by BLyS in vivo were evaluated by characterizing immune responses directed against PsaA. Results The PsaA-BLyS fusion protein was able to act as a co-stimulant for murine spleen cell proliferation induced with F(ab')2 fragments of anti-IgM in vitro in a fashion similar to recombinant BLyS, and immunization of mice with the PsaA-BLyS fusion protein resulted in dramatically elevated serum antibodies specific for PsaA. Mice immunized with PsaA admixed with recombinant BLyS exhibited only modest elevations in PsaA-specific responses following two immunizations, while mice immunized twice with PsaA alone exhibited undetectable PsaA-specific serum antibody responses. Sera obtained from PsaA-BLyS immunized mice exhibited high titers of IgG1, IgG2a, IgG2b, and IgG3, but no IgA, while mice immunized with PsaA admixed with BLyS exhibited only elevated titers of IgG1 following two immunizations. Splenocytes from PsaA-BLyS immunized mice exhibited elevated levels of secretion of IL-2, IL-4 and IL-5, and a very modest but consistent elevation of IFN-γ following in vitro stimulation with PsaA. In contrast, mice immunized with either PsaA admixed with BLyS or PsaA alone exhibited modestly elevated to absent PsaA-specific recall responses for the same cytokines. Mice deficient for one of the three receptors for BLyS designated Transmembrane activator, calcium modulator, and cyclophilin ligand [CAML] interactor (TACI) exhibited attenuated Psa

  6. A randomized phase II study of pomegranate extract for men with rising PSA following initial therapy for localized prostate cancer

    PubMed Central

    Paller, CJ; Ye, X; Wozniak, PJ; Gillespie, BK; Sieber, PR; Greengold, RH; Stockton, BR; Hertzman, BL; Efros, MD; Roper, RP; Liker, HR; Carducci, MA

    2012-01-01

    BACKGROUND Pomegranate juice has been associated with PSA doubling time (PSADT) elongation in a single-arm phase II trial. This study assesses biological activity of two doses of pomegranate extract (POMx) in men with recurrent prostate cancer, using changes in PSADT as the primary outcome. METHODS This randomized, multi-center, double-blind phase II, dose-exploring trial randomized men with a rising PSA and without metastases to receive 1 or 3 g of POMx, stratified by baseline PSADT and Gleason score. Patients (104) were enrolled and treated for up to 18 months. The intent-to-treat (ITT) population was 96% white, with median age 74.5 years and median Gleason score 7. This study was designed to detect a 6-month on-study increase in PSADT from baseline in each arm. RESULTS: Overall, median PSADT in the ITT population lengthened from 11.9 months at baseline to 18.5 months after treatment (P<0.001). PSADT lengthened in the low-dose group from 11.9 to 18.8 months and 12.2 to 17.5 months in the high-dose group, with no significant difference between dose groups (P =0.554). PSADT increases >100% of baseline were observed in 43% of patients. Declining PSA levels were observed in 13 patients (13%). In all, 42% of patients discontinued treatment before meeting the protocol-definition of PSA progression, or 18 months, primarily due to a rising PSA. No significant changes occurred in testosterone. Although no clinically significant toxicities were seen, diarrhea was seen in 1.9% and 13.5% of patients in the 1- and 3-g dose groups, respectively. CONCLUSIONS POMx treatment was associated with ≥6 month increases in PSADT in both treatment arms without adverse effects. The significance of this on-study slowing of PSADT remains unclear, reinforcing the need for placebo-controlled studies in this patient population. PMID:22689129

  7. High adsorption capacity NaOH-activated carbon for dye removal from aqueous solution.

    PubMed

    Wu, Feng-Chin; Tseng, Ru-Ling

    2008-04-15

    In this study, the surface coverage ratio (Sc/Sp) and monolayer cover adsorption amount per unit surface area (qmon/Sp) were employed to investigate the adsorption isotherm equilibrium of the adsorption of dyes (AB74, BB1 and MB) on NaOH-activated carbons (FWNa2, FWNa3 and FWNa4); the adsorption rate of the Elovich equation (1/b) and the ratio of 1min adsorption amount of adsorbate to the monolayer cover amount of adsorbate (q1/qmon) were employed to investigate adsorption kinetics. The qmon/Sp of NaOH-activated carbons was better than that of KOH-activated carbons prepared from the same raw material (fir wood). The Sc/Sp values of the adsorption of all adsorbates on adsorbent FWNa3 in this study were found to be higher than those in related literature. Parameters 1/b and q1 of the adsorption of dyes on activated carbons in this study were higher than those on KOH-activated carbons; the q1/qmon value of FWNa3 was the highest. The pore structure and the TPD measurement of the surface oxide groups were employed to explain the superior adsorption performance of FWNa3. A high surface activated carbon (FWNa3) with excellent adsorption performance on dyes with relation to adsorption isotherm equilibrium and kinetics was obtained in this study. Several adsorption data processing methods were employed to describe the adsorption performance.

  8. INFLUENCE OF THE KRAMER EFFECT ON ADSORPTION ON METALS.

    DTIC Science & Technology

    ADSORPTION, *ALLOYS, *FILMS, *METALS, *PROCESSING, ACIDS, ALCOHOLS , CYCLOHEXANES, EXCHANGE REACTIONS , FATTY ACIDS, HEAT TREATMENT , LEAD ALLOYS...LINOLENIC ACID, MACHINING , MEASUREMENT, MONOMOLECULAR FILMS, OLEIC ACID, SURFACES, TIN ALLOYS, WATER

  9. Kinetics and equilibrium adsorption studies of dimethylamine (DMA) onto ion-exchange resin.

    PubMed

    Hu, Qinhai; Meng, Yuanyuan; Sun, Tongxi; Mahmood, Qaisar; Wu, Donglei; Zhu, Jianhang; Lu, George

    2011-01-30

    The fine grained resin ZGSPC106 was used to adsorb dimethylamine (DMA) from aqueous solution in the present research. Batch experiments were performed to examine the effects of initial pH of solution and agitation time on the adsorption process. The thermodynamics and kinetics of adsorption were also analyzed. The maximum adsorption was found at natural pH of DMA solution and equilibrium could be attained within 12 min. The equilibrium adsorption data were conformed satisfactorily to the Langmuir equation. The evaluation based on Langmuir isotherm gave the maximal static saturated adsorption capacity of 138.89 mg/g at 293K. Various thermodynamic parameters such as free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) showed that the adsorption was spontaneous, endothermic and feasible. DMA adsorption on ZGSPC106 fitted well to the pseudo-second-order kinetic model. Furthermore, the adsorption mechanism was discussed by Fourier transform infrared spectroscopy (FT-IR) analysis.

  10. Removal of Ni (II) from aqueous solutions by adsorption onto Ricinus communis seed shell activated carbons.

    PubMed

    Thamilarasu, P; Karunakaran, K

    2011-01-01

    The adsorption studies on the removal of Ni(II) from aqueous solution using Ricinus communis seed shells activated carbon and polypyrrole coated Ricinus communis seed shells activated carbon were carried out under various experimental conditions. The effects of various process parameters have been investigated by following the batch adsorption technique. Adsorption data was modeled with Freundlich, Langmuir and tempkin adsorption isotherms. Thermodynamics parameters such as DeltaH0, DeltaS0, and DeltaG0 were calculated indicating that the adsorption was spontaneous and endothermic nature. A mechanism, involving intra particle diffusion and surface adsorption, has been proposed for the adsorption of Ni(II) onto the adsorbent. Adsorbent used in this study is characterized by FTIR and SEM before and after the adsorption of metal ions.

  11. Investigation of dye adsorption onto activated carbon from the shells of Macoré fruit.

    PubMed

    Aboua, Kouassi Narcisse; Yobouet, Yao Augustin; Yao, Kouassi Benjamin; Goné, Droh Lanciné; Trokourey, Albert

    2015-06-01

    The activated carbon obtained from the shells of Macoré fruit was used as an adsorbent for the removal of dyes such as methylene blue (MB) and methyl orange (MO) from synthetic contaminated aqueous solutions. It holds that the adsorption is more favourable at acidic pH, with an optimum adsorption at pH = 2. At this pH, the adsorption rate is more than 98% for the two dyes. The sorption capacity was enhanced by increasing the amount of activated carbon. Above room temperature, the adsorption rates remain constant at a value of approximately 99%. The study of the adsorption kinetics indicates that the adsorption on the studied dyes follows second-order kinetics. The isotherm adsorption data were found to be described by both Langmuir and Freundlich. In addition, the thermodynamic studies revealed that the adsorption process is a favourable, endothermic and spontaneous phenomenon.

  12. Adsorption of 2,4,6-trinitrotoluene on carboxylated porous polystyrene microspheres

    NASA Astrophysics Data System (ADS)

    Ye, Zhengfang; Meng, Qingqiang; Lu, Shengtao

    2012-02-01

    Large-pore-size (150 nm) polystyrene (PSt) microspheres were carboxylated with phthalic anhydride (PA) through Friedel-Crafts acetylation to study the adsorption of 2,4,6-trinitrotoluene (TNT) on this material from aqueous solution. The scanning electron microscope (SEM) images and mercury porosimetry measurements (MPM) of the microspheres showed that the pore structure was unchanged during the reaction. High adsorption capacity (11.2 mg g-1 of suction-dried adsorbent) and adsorption rate (33.9 mg g-1 h-1) for TNT were observed during the study. As shown by the adsorption isotherm, the adsorption of TNT on PA-PSt can be described by the Freundlich adsorption equation, indicating heterogeneous adsorption process. On-column adsorption of TNT on PA-PSt and elution indicated that TNT can be completely removed from aqueous solution and condensed into acetone.

  13. [Adsorption-desorption Characteristics of Fermented Rice Husk for Ferrous and Sulfur Ions].

    PubMed

    Xie, Xiao-mei; Liao, Min; Hua, Jia-yuan; Chen, Na; Zhang, Nan; Xu, Pei-zhi; Xie Kai-zhi; XU, Chang-xu; Liu, Guang-rong

    2015-10-01

    To understand the potential of rice husk to fix Fe2+ and S2- ions, the sorption of Fe2+ and S2- by fermented rice husk was studied by using batch incubation experiments in the present study. The effects of adsorption time, Fe2+ and S2- concentration, pH, the temperature and ionic strength in adsorption reaction solution on the sorption were investigated. Therefore, the stability of Fe2+ and S2- adsorbed by fermented rice husk was further validated by desorption experiments performed under similar conditions as adsorption. The results showed that, the adsorption kinetics of Fe2+ (r = 0.912 1) and S2- (r = 0.901 1) by fermented rice husk fits the Elovich kinetics equation, and Freundlich isotherm model could simulate the isotherm adsorption processes of Fe2+ (R2 = 0.965 1) and S2- (R2 = 0.936 6) on fermented rice husk was better than other models. The adsorption processes on fermented rice husk were non- preferential adsorption for Fe2+ and S2, while the adsorption process of Fe2+ on fermented rice husk was spontaneous reaction and the adsorption process of S2- was non-spontaneous reaction. The adsorption processes of Fe2+ and S2- on fermented rice husk were endothermic process since high temperature could benefit to the adsorption. The adsorption mechanism of Fe2+ on fermented rice husk was mainly controlled by coordination adsorption, the adsorption mechanism of S2- on fermented rice husk was mainly controlled by ligand exchange adsorption. The adsorption processes of Fe2+ and S2- on fermented rice husk showed greater pH adaptability which ranged from 1.50 to 11.50. With the increasing of ionic strength, the amount of adsorbed Fe2+ on fermented rice husk wasincreased in some extent, the amount of adsorbed S2- on fermented rice husk was slightly decreased, which further proved the adsorption of Fe2+ was major in inner sphere complexation and the adsorption of S2- was major in outer complexation. The desorption rates of Fe2+ and S2- which was adsorbed by fermented

  14. Adsorption of methylene blue from aqueous solution by graphene.

    PubMed

    Liu, Tonghao; Li, Yanhui; Du, Qiuju; Sun, Jiankun; Jiao, Yuqin; Yang, Guangming; Wang, Zonghua; Xia, Yanzhi; Zhang, Wei; Wang, Kunlin; Zhu, Hongwei; Wu, Dehai

    2012-02-01

    Graphene was prepared using a modified Hummers' method. The physico-chemical properties of graphene were characterized by TEM, BET specific surface area, FTIR, Raman and XRD measurements. The effect factors including pH, contact time, temperature and dosage on the adsorption properties of methylene blue onto graphene were investigated. The experimental data of isotherm followed the Langmuir isotherm model better than the Freundlich model. The maximum adsorption capacity obtained from Langmuir isotherm equation at 293 K was 153.85 mg/g, indicating graphene is a good adsorbent for the adsorption of MB. The kinetic study illustrated that the adsorption of methylene blue onto graphene fit the pseudo second-order model. The thermodynamic parameters indicated that the adsorption of methylene blue onto graphene was an endothermic and spontaneous process.

  15. Hydrogen-graphite interaction: Experimental evidences of an adsorption barrier

    NASA Astrophysics Data System (ADS)

    Aréou, E.; Cartry, G.; Layet, J.-M.; Angot, T.

    2011-01-01

    The interaction of H atoms having relatively low average kinetic energy (˜0.025 eV) with both perfectly clean and D-covered HOPG surfaces is investigated using high resolution electron energy loss spectroscopy. From this study we confirm, in a controlled fashion, the presence of the theoretically predicted adsorption barrier since no adsorption is detected for such H atoms on HOPG. Moreover, we demonstrate that the exposure of a D saturated HOPG surface to these H atoms results in the complete removal of adatoms, with no further adsorption despite the prediction of the adsorption barrier to vanish for H dimers in para configuration. Therefore, the recombinative abstraction mechanism which competes with the adsorption process is more efficient.

  16. Adsorption of arsenate on untreated dolomite powder.

    PubMed

    Ayoub, G M; Mehawej, M

    2007-09-05

    Raw dolomite powder was evaluated for its efficiency in adsorbing As(V) from water. An experimental setup comprised of a fluidized dolomite powder bed was used to assess the impact of various test variables on the efficiency of removal of As(V). Test influents including distilled water (DW), synthetic groundwater (SGW) and filtered sewage effluent (FSE) were employed to assess the effect of influent parameters on the adsorption process and the quality of the effluent generated. Dolomite exhibited good As(V) removal levels for distilled water (>92%) and synthetic ground water (>84%) influents at all initial As(V) concentrations tested (0.055-0.600 ppm). Breakthrough of dolomite bed occurred after 45 bed volumes for DW and 20 bed volumes for SGW influents with complete breakthrough taking place at more than 300 bed volumes. As(V) removal from FSE influents was relatively unsuccessful as compared to the DW and SGW influents. Partial removal in the order of 32% from filtered sewage effluent at initial concentration of 0.6 mg/L started at 75 bed volumes and gradually stopped at 165 bed volumes. Varying degrees of As(V) adsorption capacities were observed by the different test influents employed, which indicate that the adsorption of As(V) is adversely affected by competing species, mainly sulfates and phosphates present in the influent. The adsorptive behavior of dolomite was described by fitting data generated from the study into the Langmuir and Freundlich isotherm models. Both models described well the adsorption of dolomite. The average isotherm adsorptive capacity was determined at 5.02 mug/g. Regeneration of the dolomite bed can be achieved with the use of caustic soda solution at a pH of 10.5.

  17. Assessment of multi-mycotoxin adsorption efficacy of grape pomace.

    PubMed

    Avantaggiato, Giuseppina; Greco, Donato; Damascelli, Anna; Solfrizzo, Michele; Visconti, Angelo

    2014-01-15

    Grape pomace (pulp and skins) was investigated as a new biosorbent for removing mycotoxins from liquid media. In vitro adsorption experiments showed that the pomace obtained from Primitivo grapes is able to sequester rapidly and simultaneously different mycotoxins. Aflatoxin B1 (AFB1) was the most adsorbed mycotoxin followed by zearalenone (ZEA), ochratoxin A (OTA), and fumonisin B1 (FB1), whereas the adsorption of deoxynivalenol (DON) was negligible. AFB1 and ZEA adsorptions were not affected by changing pH values in the pH 3-8 range, whereas OTA and FB1 adsorptions were significantly affected by pH. Equilibrium adsorption isotherms obtained at different temperatures (5-70 °C) and pH values (3 and 7) were modeled and evaluated using the Freundlich, Langmuir, Sips, and Hill models. The goodness of the fits and the parameters involved in the adsorption mechanism were calculated by the nonlinear regression analysis method. The best-fitting models to describe AFB1, ZEA, and OTA adsorption by grape pomace were the Sips, Langmuir, and Freundlich models, respectively. The Langmuir and Sips models were the best models for FB1 adsorption at pH 7 and 3, respectively. The theoretical maximum adsorption capacities (mmol/kg dried pomace) calculated at pH 7 and 3 decreased in the following order: AFB1 (15.0 and 15.1) > ZEA (8.6 and 8.3) > OTA (6.3-6.9) > FB1 (2.2 and 0.4). Single- and multi-mycotoxin adsorption isotherms showed that toxin adsorption is not affected by the simultaneous presence of different mycotoxins in the liquid medium. The profiles of adsorption isotherms obtained at different temperatures and pH and the thermodynamic parameters (ΔG°, ΔH°, ΔS°) suggest that mycotoxin adsorption is an exothermic and spontaneous process, which involves physisorption weak associations. Hydrophobic interactions may be associated with AFB1 and ZEA adsorption, whereas polar noncovalent interactions may be associated with OTA and FB1 adsorption. In conclusion, this study

  18. Characterization of biochars derived from agriculture wastes and their adsorptive removal of atrazine from aqueous solution: A comparative study.

    PubMed

    Liu, Na; Charrua, Alberto Bento; Weng, Chih-Huang; Yuan, Xiaoling; Ding, Feng

    2015-12-01

    The physicochemical properties of biochars produced from soybeans (SBB), corn stalks (CSB), rice stalks (RSB), poultry manure (PMB), cattle manure (CMB), and pig manure (PgMB) and their adsorption characteristics of atrazine were investigated. The adsorption capacity increased with the increase of temperature and initial atrazine concentration. More atrazine was removed from basic solutions than acidic solutions, due to the effects of adsorption and hydrolysis. The Freundlich isotherm adsorption parameters indicated that the adsorption capacity decreased in the order SBB>RSB>CMB>CSB>PMB>PgMB, which is associated to the pore volume of biochars. The total pore volume and biochar pH were concluded to play important roles in determining the adsorption capacity, and they may have contributed to physical adsorption mechanisms dominating the overall adsorption process (the low activation energy for all of the biochars). Modified Freundlich and intraparticle diffusion models were used to describe the kinetics of the adsorption process.

  19. Isotherms for Water Adsorption on Molecular Sieve 3A: Influence of Cation Composition

    SciTech Connect

    Lin, Ronghong; Ladshaw, Austin; Nan, Yue; Liu, Jiuxu; Yiacoumi, Sotira; Tsouris, Costas; DePaoli, David W.; Tavlarides, Lawrence L.

    2015-06-16

    This study is part of our continuing efforts to address engineering issues related to the removal of tritiated water from off-gases produced in used nuclear fuel reprocessing facilities. In the current study, adsorption equilibrium of water on molecular sieve 3A beads was investigated. Adsorption isotherms for water on the UOP molecular sieve 3A were measured by a continuous-flow adsorption system at 298, 313, 333, and 353 K. Experimental data collected were analyzed by the Generalized Statistical Thermodynamic Adsorption (GSTA) isotherm model. The K+/Na+ molar ratio of this particular type of molecular sieve 3A was ~4:6. Our results showed that the GSTA isotherm model worked very well to describe the equilibrium behavior of water adsorption on molecular sieve 3A. The optimum number of parameters for the current experimental data was determined to be a set of four equilibrium parameters. This result suggests that the adsorbent crystals contain four energetically distinct adsorption sites. In addition, it was found that water adsorption on molecular sieve 3A follows a three-stage adsorption process. This three-stage adsorption process confirmed different water adsorption sites in molecular sieve crystals. In addition, the second adsorption stage is significantly affected by the K+/Na+ molar ratio. In this stage, the equilibrium adsorption capacity at a given water vapor pressure increases as the K+/Na+ molar ratio increases.

  20. Isotherms for Water Adsorption on Molecular Sieve 3A: Influence of Cation Composition

    DOE PAGES

    Lin, Ronghong; Ladshaw, Austin; Nan, Yue; ...

    2015-06-16

    This study is part of our continuing efforts to address engineering issues related to the removal of tritiated water from off-gases produced in used nuclear fuel reprocessing facilities. In the current study, adsorption equilibrium of water on molecular sieve 3A beads was investigated. Adsorption isotherms for water on the UOP molecular sieve 3A were measured by a continuous-flow adsorption system at 298, 313, 333, and 353 K. Experimental data collected were analyzed by the Generalized Statistical Thermodynamic Adsorption (GSTA) isotherm model. The K+/Na+ molar ratio of this particular type of molecular sieve 3A was ~4:6. Our results showed that themore » GSTA isotherm model worked very well to describe the equilibrium behavior of water adsorption on molecular sieve 3A. The optimum number of parameters for the current experimental data was determined to be a set of four equilibrium parameters. This result suggests that the adsorbent crystals contain four energetically distinct adsorption sites. In addition, it was found that water adsorption on molecular sieve 3A follows a three-stage adsorption process. This three-stage adsorption process confirmed different water adsorption sites in molecular sieve crystals. In addition, the second adsorption stage is significantly affected by the K+/Na+ molar ratio. In this stage, the equilibrium adsorption capacity at a given water vapor pressure increases as the K+/Na+ molar ratio increases.« less

  1. Adsorption of mercury on laterite from Guizhou Province, China.

    PubMed

    Yu, Xiaohong; Zhu, Lijun; Guo, Baiwei; He, Shouyang

    2008-01-01

    The adsorption behaviors of Hg(II) on laterite from Guizhou Province, China, were studied and the adsorption mechanism was discussed. The results showed that different mineral compositons in the laterite will cause differences in the adsorption capacity of laterite to Hg(II). Illite and non-crystalloids are the main contributors to enhancing the adsorption capacity of laterite to Hg(II). The pH of the solution is an important factor affecting the adsorption of Hg(II) on laterite. The alkalescent environment (pH 7-9) is favorable to the adsorption of Hg(II). The amount of adsorbed Hg(II) increases with increasing pH. When the pH reaches a certain value, the amount of the adsorbed Hg(II) will reach the maximum level. The amount of adsorbed Hg(II) decreases with increasing pH. The optimal pHs of laterite and kaolinite are 9 and 8, respectively. The optimal initial concentrations of Hg(II) on laterite and kaolinite are 250 and 200 microg/ml, respectively. The adsorption isotherms were described by the Langmuir model. The adsorption of Hg(II) on laterite is a quick process while that of Hg(II) on kaolinite is a slow reaction. Laterite from Guizhou Province is a promising environmental material which can be used in the removal of Hg(II) from wastewater.

  2. Adsorption and desorption characteristics of arsenic onto ceria nanoparticles

    NASA Astrophysics Data System (ADS)

    Feng, Qinzhong; Zhang, Zhiyong; Ma, Yuhui; He, Xiao; Zhao, Yuliang; Chai, Zhifang

    2012-01-01

    The rapid increase in the use of engineered nanoparticles [ENPs] has resulted in an increasing concern over the potential impacts of ENPs on the environmental and human health. ENPs tend to adsorb a large variety of toxic chemicals when they are emitted into the environment, which may enhance the toxicity of ENPs and/or adsorbed chemicals. The study was aimed to investigate the adsorption and desorption behaviors of arsenic on ceria NPs in aqueous solution using batch technique. Results show that the adsorption behavior of arsenic on ceria NPs was strongly dependent on pH and independent of ionic strength, indicating that the electrostatic effect on the adsorption of these elements was relatively not important compared to surface chemical reactions. The adsorption isotherms fitted very well to both the Langmuir and Freundlich models. The thermodynamic parameters (Δ H 0 , Δ S 0 , and Δ G 0 ) for the adsorption of arsenic were determined at three different temperatures of 283, 303, and 323 K. The adsorption reaction was endothermic, and the process of adsorption was favored at high temperature. The desorption data showed that desorption hysteresis occurred at the initial concentration studied. High adsorption capacity of arsenic on ceria NPs suggests that the synergistic effects of ceria NPs and arsenic on the environmental systems may exist when they are released into the environment.

  3. Adsorption behavior of some radionuclides on the Chinese weathered coal.

    PubMed

    Wu, Jianfeng; Xu, Qichu; Bai, Tao

    2007-08-01

    The equilibrium and kinetic properties of Am(III), Eu(III) and Cs(I) ions adsorption by three weathered coals (WCs) from China, have been investigated in batch stirred-tank experiments. The effects of contact time, solution acidity and initial sorbate concentration on the adsorption of Am(III), Eu(III) and Cs(I) by Yuxian(YX) Tongchuan (TC) and Pingxiang (PX) WC were evaluated. The radionuclide ions are able to form complex compounds with carboxylic and phenolic groups of WCs and they are also bounded with phenolic groups even at high acidity reaction solution (>0.1 mol/L). Mechanisms including ion exchange, complexation and adsorption to the coal surface are possible in the sorption process. The acidity of the solution played an important role in the adsorption. Even acidity as high as 0.1 mol/L, 60% of Am(III) or Eu(III), 40% of Cs(I) were found to be sorbed on the YX WC, which had the best adsorption capacity for Am(III) and Eu(III). Our batch adsorption studies showed the equilibrium adsorption data fit the linear Langmuir and Freundlich adsorption isotherm. The maximum equilibrium uptake of Eu(III) were 0.412, 3.701, 5.446 mmol/g for JXWC, TCWC and YXWC, respectively.

  4. Regenerable adsorption system