Science.gov

Sample records for adsorption psa process

  1. Adsorption dynamics of a layered bed PSA for H{sub 2} recovery from coke oven gas

    SciTech Connect

    Yang, J.; Lee, C.H.

    1998-06-01

    The adsorption dynamics of a layered bed packed with activated carbon and zeolite 5A were studied experimentally and theoretically through breakthrough experiments and two-bed pressure swing adsorption (PSA) processes by using coke oven gas (56.4 vol.% H{sub 2}; 26.6 vol.% CH{sub 4}; 8.4 vol.% CO; 5.5 vol.% N{sub 2}; and 3.1 vol.% CO{sub 2}). The results of breakthrough curves of a layered bed showed an intermediate behavior of those of zeolite-5A bed and activated carbon bed, because each concentration front propagates with its own wavefront velocity in each layer by a different adsorption equilibrium. Since a fast and dispersed mass-transfer zone of CO in the zeolite layer of a layered bed leads to a long leading front of the N{sub 2} wavefront, controlling the leading wavefront of the N{sub 2} plays a very important role in obtaining a high-purity product and in determining the optimum carbon ratio of a PSA process for H{sub 2} recovery from coke oven gas. The layered bed PSA process was simulated in a simplified form of two single-adsorbent beds linked in series. The dynamic model incorporating mass, energy, and momentum balances agreed well with the experimental data. Concentration profiles inside the adsorption bed were also investigated.

  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. Adsorption processing - Optimization through understanding

    SciTech Connect

    Not Available

    1986-01-01

    Adsorption processes used in the natural gas industry for dehydration, sweetening and liquids recovery are batch systems, very similar to laboratory chromatographs. For continuous processing a plant must contain multiple adsorbers, so that while one column adsorbs, another or others can be desorbed and prepared for their next turn at adsorption. Variations in the cycle, the number of adsorbers and the way multiple towers may be sequenced; in series, in parallel, etc. are so numerous that an entire presentation could be devoted to the reasons and results of the various arrangements. For a consideration of the process fundamentals and the way they can be manipulated, this discussion concentrates on a simple two tower system typical of what is frequently used to dehydrate gas ahead of a cryogenic plant; a turboexpander unit or a peak shaving LNG facility.

  5. Physical Adsorption of Gases on Heterogeneous Solids and Equilibrium Studies of the Pressure Swing Adsorption Process.

    NASA Astrophysics Data System (ADS)

    Lu, Xiaochun

    1990-01-01

    -parameter isotherm equation based on benzene adsorption isotherms. We extended further the TVFM to derive thermodynamic functions, such as the adsorption entropy, the adsorption enthalpy, and the adsorption energy distribution, and constructed these functions for various adsorption systems based on their adsorption isotherms. To explore the energetic heterogeneity of the adsorbent, we used two approaches. First, we used the overall integral isotherm equation to obtain the Langmuir -Freundlich isotherm; and second, we used the Gibb's relation to obtain an exponential isotherm equation. The adsorption energy-distribution function can be obtained from these isotherm equations. The pressure swing adsorption (PSA) process was studied based on Shandalman and Mitchell's equilibrium theory for a PSA system with a linear isotherm. This theory was extended to a PSA system with a non-linear isotherm. Relationships were established between the isotherms and process parameters, such as the enrichment factor, the critical recycle ratio, and the extent of the recovery.

  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. 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.

  9. 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.

  10. Use of simplified PSA studies in support of the ASTRID design process

    SciTech Connect

    Gauthe, P.; Curnier, F.; Bertrand, F.; Vincon, L.; Jouve, S.; Balmain, M.; Rychkov, V.; Banchieri, Y.

    2012-07-01

    In the framework of the French Act of 28 June 2006 about nuclear materials and waste management, a GEN IV and actinides incineration demonstration prototype is to be commissioned in the 2020 decade. In this objective a prototype called ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration) is proposed to demonstrate the progress made in SFR technology at an industrial scale by qualifying innovative options, some of which still remain open in the areas requiring improvements, especially safety and operability. More specifically, we aim for a level of safety that is at least equivalent to that of the EPR (third generation), with improvements made in SFR-specific fields. The integration of safety issues in the early phase of the design of ASTRID is necessarily expected. For this purpose, CEA and its partners AREVA and EDF have planned to perform a level-1 PSA to support and orientate the preliminary design of ASTRID reactor. This paper presents the PSA approach and current studies for the assessment of safety systems and the future work to be done for the 2012-2014 period. The preliminary preparation of PSA studies is presented: objectives and scope of the early design phase PSA, definition of core damage states, selection and grouping of initiating events, assessment of safety functions and related systems. Work under progress is also presented: modelling of event trees, construction of fault trees of safety systems, transient calculations of accident sequences with the CATHARE2 code and reliability data assessment. Main objectives of a level-1 PSA performed at conceptual design stage are an early assessment of the safety architecture of the reactor and findings about the most effective areas for improvement, but also the identification of dominant accident sequences and comparison with alternative designs. After the elaboration of a simplified level-1 PSA model for nominal state and main internal initiators, various design alternatives will be

  11. Superstructure-based optimal design of PSA cycles for post-combustion CO2 capture

    SciTech Connect

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

    2009-07-01

    Recent developments have shown pressure/vacuum swing adsorption (PSA/VSA) to be a promising option to effectively capture CO2 from flue gas streams. In most commercial PSA cycles, the weakly adsorbed component in the mixture is the desired product, and enriching the strongly adsorbed CO2 is not a concern. Thus, it is necessary to develop PSA processes specifically targeted to obtain pure strongly adsorbed component. So far, no systematic methodology has been suggested in the literature to design PSA cycles for high purity CO2 capture. This study addresses this need and presents a systematic optimization-based formulation to synthesize PSA cycles. In particular, a novel PSA superstructure is presented to design optimal PSA cycle configurations and evaluate CO2 capture strategies. The superstructure is rich enough to predict a number of different PSA operating steps. The bed connections in the superstructure are governed by timedependent control variables, which can be varied to realize most PSA operating steps. An optimal sequence of operating steps is achieved through the formulation of an optimal control problem with the partial differential and algebraic equations of the PSA system and the cyclic steady state condition. The superstructure approach is demonstrated for case studies related to post-combustion CO2 capture. In particular, optimal PSA cycles were synthesized which maximize CO2 recovery for a given purity, and minimize overall power consumption. The results show the potential of the superstructure to predict PSA cycles with up to 98% purity and recovery of CO2. Moreover, for recovery of around 85% and purity of over 90%, these cycles can recover CO2 from atmospheric flue gas with a low power consumption of 465 kWh/tonne CO2. The approach presented is, therefore, very promising and quite useful for evaluating the suitability of different adsorbents, feedstocks and operating strategies for PSA, and assessing its usefulness for CO2 capture.

  12. 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.

  13. A superstructure-based optimal synthesis of PSA cycles for post-combustion CO2 capture

    SciTech Connect

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

    2010-07-01

    Recent developments have shown pressure/vacuum swing adsorption (PSA/VSA) to be a promising option to effectively capture CO2 from flue gas streams. In most 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, it is necessary to concentrate CO2 to high purity to reduce CO2 sequestration costs and minimize safety and environmental risks. Thus, it is necessary to develop PSA processes specifically targeted to obtain pure strongly adsorbed component. A multitude of PSA/VSA cycles have been developed in the literature for CO2 capture from feedstocks low in CO2 concentration. However, no systematic methodology has been suggested to develop, evaluate, and optimize PSA cycles for high purity CO2 capture. This study presents a systematic optimization-based formulation to synthesize novel PSA cycles for a given application. In particular, a novel PSA superstructure is presented to design optimal PSA cycle configurations and evaluate CO2 capture strategies. The superstructure is rich enough to predict a number of different PSA operating steps. The bed connections in the superstructure are governed by time-dependent control variables, which can be varied to realize most PSA operating steps. An optimal sequence of operating steps is achieved through the formulation of an optimal control problem with the partial differential and algebraic equations of the PSA system and the cyclic steady state condition. Large-scale optimization capabilities have enabled us to adopt a complete discretization methodology to solve the optimal control problem as a largescale nonlinear program, using the nonlinear optimization solver IPOPT. The superstructure approach is demonstrated for case studies related to post-combustion CO2 capture. In particular, optimal PSA cycles were synthesized, which maximize CO2 recovery for a given purity, and minimize overall power consumption. The

  14. Adsorption kinetic process of thiol ligands on gold nanocrystals.

    PubMed

    Cheng, Hao; Yang, Lina; Jiang, Yong; Huang, Yuanyuan; Sun, Zhihu; Zhang, Jing; Hu, Tiandou; Pan, Zhiyun; Pan, Guoqiang; Yao, Tao; Bian, Qing; Wei, Shiqiang

    2013-12-01

    Understanding the kinetic mechanism during ligand adsorption on gold nanocrystals is important for designing and fine-tuning their properties and implications. Here, we report a kinetic study on the adsorption process of dodecanethiol ligands on Au nanocrystals of 3.3 nm by an in situ time-resolved X-ray absorption fine structure technique. A two-step process of dodecanethiol adsorption on Au NC surfaces is proposed based on the obtained ligand coverage, which shows a quick increase from 0 to 0.40 within the first 20 min, followed by a much slower increase to the limiting value of 0.94. In-depth analysis suggests that the first stage involves the quick adsorption of dodecanethiol to the corner and edge sites of Au NCs surfaces, leading to remarkable surface Au-Au bond length relaxation (from 2.79 to 2.81 Å) and pronounced gold-to-ligand charge transfer. The second step that corresponds to the much slower adsorption process to the surface facets could be described by the Langmuir kinetics equation with an adsorption rate constant of 0.0132 min(-1) and an initial coverage of 0.41, in good agreement with the initially preferable adsorption of thiols to the most favorable sites. PMID:24122096

  15. 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

  16. 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

  17. 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

  18. Examples of the use of PSA in the design process and to support modifications at two research reactors

    SciTech Connect

    Johnson, D.H.; Bley, D.C.; Lin, J.C.; Ramsey, C.T.; Linn, M.A.

    1994-03-01

    Many, if not most, of the world`s commercial nuclear power plants have been the subject of plant-specific probabilistic safety assessments (PSA). A growing number of other nuclear facilities as well as other types of industrial installations have been the focus of plant-specific PSAs. Such studies have provided valuable information concerning the nature of the risk of the individual facility and have been used to identify opportunities to manage that risk. This paper explores the risk management activities associated with two research reactors in the United States as a demonstration of the versatility of the use of PSA to support risk-related decision making.

  19. 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.

  20. PSA blood test (image)

    MedlinePlus

    Prostate-specific antigen (PSA) is a glycoprotein in the cytoplasm of prostatic epithelial cells. It can be detected in the blood of all adult men. The PSA level is increased in men with ... also be increased somewhat in other disorders of the prostate.

  1. 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

  2. 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

  3. 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

  4. PSA, PSA derivatives, proPSA and prostate health index in the diagnosis of prostate cancer

    PubMed Central

    Ayyıldız, Sema Nur; Ayyıldız, Ali

    2014-01-01

    Currently, prostate- specific antigen (PSA) is the most common oncological marker used for prostate cancer screening. However, high levels of PSA in benign prostatic hyperplasia and prostatitis decrease the specificity of PSA as a cancer marker. To increase the specificity of PSA, PSA derivatives and PSA kinetics have been used. However, these new techniques were not able to increase the diagnostic specificity for prostate cancer. Therefore, the search for new molecules and derivatives of PSA continues. With the aim of increasing the specificity of prostate cancer diagnosis, proPSA and the Prostate Health Index have been introduced. In this review, the roles of PSA, PSA derivatives, proPSA and the Prostate Health Index in Prostate Cancer diagnosis are examined. PMID:26328156

  5. 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. PMID:27209397

  6. Two-scale modeling of adsorption processes at structured surfaces

    NASA Astrophysics Data System (ADS)

    Kundin, Julia; de Cuba, Maria Radke; Gemming, Sibylle; Emmerich, Heike

    2009-01-01

    We present an algorithm for the simulation of vicinal surface growth. It combines a lattice gas anisotropic Ising model with a phase-field model. The molecular behavior of individual adatoms is described by the lattice gas model. The microstructure dynamics on the vicinal surface are calculated using the phase-field method. In this way, adsorption processes on two different length scales can be described: nucleation processes on the terraces (lattice gas model) and step-flow growth (phase field model). The hybrid algorithm that is proposed here, is therefore able to describe an epitaxial layer-by-layer growth controlled by temperature and by deposition rate. This method is faster than kinetic Monte Carlo simulations and can take into account the stochastic processes in a comparable way.

  7. CO[sub 2] recovery in molten carbonate fuel cell system by pressure swing adsorption

    SciTech Connect

    Sasaki, A.; Matsumoto, S.; Fujitsuka, M.; Shinoki, T.; Tanaka, T. ); Ohtsuki, J. )

    1993-03-01

    The carbon dioxide recycle configuration by pressure swing adsorption (PSA) is examined in the indirect internal reforming molten carbonate fuel cell (IIR-MCFC) system, theoretically and experimentally. It is the result of system studies that the CO[sub 2] PSA makes the system efficiency higher than ordinary combustion process. A test plant is fabricated in order to evaluate the PSA performance in the IIR-MCFC system operation. The experimental results with respect to CO[sub 2] recovery ratio, purity and pressure fluctuations in both electrode chambers are acceptable. The system integration is necessary in order to decrease the auxiliary power still more and to give the control logic robust.

  8. 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

  9. 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.

  10. Modeling Adsorption Processes: Issues in Uncertainty, Scaling, and Prediction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adsorption of contaminant species to mineral surfaces is largely responsible for the retardation of radionuclides in the subsurface environment. However despite much research effort, the advancement of models that can be used to successfully calculate or predict adsorption is still somewhat limited...

  11. 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

  12. Visualizing flocculation and adsorption processes in papermaking using fluorescence microscopy

    SciTech Connect

    Whipple, W.L.; Maltesh, C.

    2000-04-04

    Polymer adsorption characteristics in complex papermaking systems have been elucidated using tagged reagents and the well-established technique of fluorescence microscopy. Interactions between polymers and components of papermaking slurries have been previously well researched, but the theories put forth are usually based on indirect references. Moreover, the use of simple model systems often does not permit correlation with real systems. The present study clearly shows that, under shear conditions and time scales prevalent on a paper machine, polymer partitions to inorganic fillers and fiber fines. In the absence of fillers, the polymer adheres to high surface area regions of the fiber, viz., fibrils that result from mechanical fiber processing operations. The roles of surface area, electrostatic interactions, and other papermaking operations are discussed in detail. The authors believe this study to be the first extension of fluorescence microscopy for visualizing polymer partitioning in complex systems such as papermaking slurries. On the basis of the data provided here, it should be facile to extend this application for studying polymer behavior in other systems such as sludge dewatering and mineral processing.

  13. 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.

  14. 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.

  15. PSA in America

    SciTech Connect

    Linn, M.A.; Cunningham, M.A.; Johnson, D.H.

    1996-12-31

    Although the concept of acceptable risk has always been the foundation of the nuclear industry design, the use of formal PSA (or PRA-probabilistic risk assessment) in the U.S. nuclear power industry has followed an unusual path in arriving at its current level of notability. Prior to 1975, probabilistic evaluations were limited to a few specific applications such as the evaluation of man-made (i.e., airplane crashes) and natural (i.e., earthquakes) hazards. In 1975, the industry was introduced to comprehensive PSA by the Reactor Safety Study (WASH-1400). However, the study languished in relative obscurity until the accident at Three Mile Island 2 (TMI-2) in 1979. This event significantly altered the industry`s view of severe accidents in the U.S. and worldwide. Investigative committees of TMI-2 recommended that PSA techniques be more widely used to augment the traditional deterministic methods of determining nuclear plant safety. This initiated an unprecedented effort by nuclear regulators and licensees worldwide to significantly improve the state of knowledge of severe accidents at nuclear power plants. In the U.S., use of PSA began to increase as evidenced by its application in the anticipated transient without scram and station blackout rulemakings, generic issue prioritization and resolution, risk-based inspection guidelines, backfit policy, and technical specification improvements. However, broad application of probabilistic techniques to the industry as a whole was initiated in 1986 with the publication of Safety Goals for the Operation of Nuclear Power Plant; Policy Statement. This put PSA front and center in the U.S. regulatory arena by {open_quotes}establish[ing] goals that broadly define an acceptable level of radiological risk that might be imposed on the public as a result of nuclear power plant operation.{close_quotes} Both qualitative safety goals and quantitative objectives were articulated in this policy statement.

  16. 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.

  17. 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. PMID:22082527

  18. Effects of carbon-to-zeolite ratio on layered bed H{sub 2} PSA for coke oven gas

    SciTech Connect

    Lee, C.H.; Yang, J.; Ahn, H.

    1999-03-01

    Effects of carbon-to-zeolite ratio on a layered bed H{sub 2} PSA using activated carbon and zeolite 5A were studied experimentally and theoretically. Coke oven gas (56.,4 vol.% H{sub 2}, 26.6 vol.% CH{sub 4}, 8.4 vol.% CO, 5.5 vol. % N{sub 2}, and 3.1 vol.% CO{sub 2}) was used as a feed gas for the seven-step two-bed PSA process incorporating a backfill step. In these experiments, the effects of three operating variables such as adsorption pressure, feed rate and purge rate on the performance of a layered bed PSA were investigated. The layered bed gave better purity than the single-adsorbent bed at the same operating condition, except at low purge rate. Since every component had its own front velocity at each layer, a carbon-to-zeolite ratio affected product purity at a given recovery or throughput. Moreover, for a high-purity H{sub 2} product from coke oven gas, an optimum carbon-to-zeolite ratio had to be determined to control a leading wavefront of N{sub 2}. In layered bed PSA processes, the temperature variations inside the bed reflected a kind of inflection or plateau at which a roll-up phenomenon occurred and showed the dynamics of adsorption well at each step during a cycle. Simulated results of the dynamic model incorporating mass, energy and momentum balances agreed well with the PSA experimental results.

  19. 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. PMID:26004250

  20. 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.

  1. 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)

  2. PSA kinetics after prostate brachytherapy: PSA bounce phenomenon and its implications for PSA doubling time

    SciTech Connect

    Ciezki, Jay P. . E-mail: ciezkij@ccf.org; Reddy, Chandana A.; Garcia, Jorge; Angermeier, Kenneth; Ulchaker, James; Mahadevan, Arul; Chehade, Nabil; Altman, Andrew; Klein, Eric A.

    2006-02-01

    Purpose: To analyze prostate-specific antigen (PSA) kinetics in patients treated with prostate brachytherapy (PI) with a minimum of 5 years of PSA follow-up. Methods and Materials: The records of 162 patients treated with PI for localized prostate cancer with a minimum of 5 years of PSA follow-up were reviewed. A variety of pretreatment and posttreatment variables were examined. Patients were coded as having a PSA bounce if their PSA achieved a nadir, elevated at least 0.2 ng/mL greater than that nadir, and decreased to, or below, the initial nadir. Two definitions of biochemical failure (bF) or biochemical relapse-free survival (bRFS) were used: the classic American Society for Therapeutic Radiology and Oncology consensus definition of three consecutive rises (bF3) and the nadir plus 2 ng/mL definition (bFn+2). Associations between a PSA bounce and the various pre- and posttreatment factors were assessed with logistic regression analysis, and the association between a PSA bounce and bF was examined with the log-rank test. The Mann-Whitney U test was applied to test for differences in the PSA doubling time (PSADT) and the time to a PSA rise between the PSA bounce patients and the bF patients. PSADT was calculated from the nadir to the time of the first PSA rise, because this point is known first in the clinical setting. Results: The 5-year overall bRFS rate was 87% for the bF3 definition and 96% for the bFn+2 definition. A PSA bounce was experienced by 75 patients (46.3%). Patients who experienced a PSA bounce were less likely to have a bF, regardless of the bRFS definition used (bF3: p = 0.0015; bFn+2: p = 0.0040). Among the pre- and posttreatment factors, only younger age predicted for a PSA bounce on multivariate analysis (p = 0.0018). The use of androgen deprivation had no effect on PSA bounce. No difference was found in the PSADT between patients who had a PSA bounce and those with bF. The median PSADT for those with a PSA bounce was 8.3 months vs. 10.3 months

  3. Equilibrium and kinetic data and process design for adsorption of Congo Red onto bentonite.

    PubMed

    Bulut, Emrah; Ozacar, Mahmut; Sengil, I Ayhan

    2008-06-15

    The adsorption of Congo Red onto bentonite in a batch adsorber has been studied. Four kinetic models, the pseudo first- and second-order equations, the Elovich equation and the intraparticle diffusion equation, were selected to follow the adsorption process. Kinetic parameters; rate constants, equilibrium adsorption capacities and correlation coefficients, for each kinetic equation were calculated and discussed. It was shown that the adsorption of Congo Red onto bentonite could be described by the pseudo second-order equation. The experimental isotherm data were analyzed using the Langmuir, Freundlich and Temkin equations. Adsorption of Congo Red onto bentonite followed the Langmuir isotherm. A single stage batch adsorber was designed for different adsorbent mass/treated effluent volume ratios using the Langmuir isotherm. PMID:18055111

  4. Initial Processes of Sulfur Adsorption on Si(100) Surface

    NASA Astrophysics Data System (ADS)

    Ma, Li; Wang, Jian-Guang; Wang, Guang-Hou

    2005-10-01

    The adsorption of one monolayer S atoms on ideal Si(100) surface is studied by using the self-consistent tight binding linear muffin-tin orbital method. Energies of adsorption systems of S atoms on different sites are calculated. It is found that the adsorbed S atoms are more favorable on B1 site (bridge site) with a distance 0.131 nm above the Si surface. The S, Si mixed layer might exist at S/Si(100) interface. The layer projected density of states are calculated and compared with that of the clean surface. The charge transfers are also investigated. The project supported by National Natural Science Foundation of China under Grant Nos. 90206033 and 10274031

  5. Model of electrodialysis process associated with organic adsorption

    SciTech Connect

    Chatchupong, T.; Murphy, R.J.

    1996-02-01

    A convective-diffusion model was developed to predict the performance of both electrodialysis (ED) and adsorption on species in an aqueous solution. The quasi-steady-state model was solved by finite difference to assess the effects of a packed bed of graphite on separation of an univalent electrolyte and an organic compound in an ED cell. A sensitivity analysis of parameters in the model was also performed. Comparison of simulation results with experimental data of 2-Naphthol (2-C{sub 10}H{sub 7}OH) in sodium chloride solution was used for this case study. The model satisfactorily predicts 2-Naphthol removal at the 95% confidence level.

  6. PSA Kinetics and PSA Bounce Following Permanent Seed Prostate Brachytherapy

    SciTech Connect

    Crook, Juanita Gillan, Caitlin B.Sc.; Yeung, Ivan Ph.D.; Austen, Lynette; McLean, Michael; Lockwood, Gina M.Math.

    2007-10-01

    Purpose: To report the incidence, timing, and magnitude of the benign prostate-specific antigen (PSA) bounce after {sup 125}I prostate brachytherapy and correlate the bounce with clinical and/or dosimetric factors. Methods and Materials: From March 1999 to August 2003, a total of 292 men received {sup 125}I prostate brachytherapy without androgen deprivation or supplemental beam radiotherapy and have PSA follow-up >30 months. Implants were preplanned using transrectal ultrasound (TRUS) and performed under transrectal ultrasound/fluoroscopy guidance using preloaded needles. A PSA bounce is defined as an increase {>=}0.2 ng/ml with spontaneous return to prebounce level or lower. Results: Resolved PSA bounces were seen in 40% of men with follow-up >30 months. Median onset was 15 months, and median magnitude was 0.76 ng/ml. Magnitude >2 ng/ml was seen in 15%. The only clinical or dosimetric factor predictive of bounce in multivariate analysis was younger age. Median time to increasing PSA level indicative of failure was 30 months. Conclusions: Benign PSA bounces are common after {sup 125}I prostate brachytherapy, especially in younger men. An increase >2 ng/ml above the nadir was seen in 15%. Magnitude of increase does not distinguish bounce from failure. Time to the start of the PSA increase can be helpful, but is not absolute. The PSA bounce does not predict subsequent failure. Caution is advised in interpreting an early increasing PSA level in the first 30 months after {sup 125}I brachytherapy in favorable-risk patients.

  7. 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. PMID:27176384

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

    NASA Astrophysics Data System (ADS)

    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. 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.

  10. Process modeling of in situ-adsorption of a bacterial lipase.

    PubMed

    Millitzer, Marcus; Wenzig, Edda; Peukert, Wolfgang

    2005-12-20

    In situ adsorption, known as an in situ-roduct removal (ISPR) technique for low molecular mass bioproducts, was in this study applied to a bacterial exoenzyme proving that this method is also suitable for the separation of macromolecules like proteins. For this, adsorbent particles were added to growing cultures of Staphylococcus carnosus rec., therefore both production and adsorption occurred simultaneously in shaking flasks, stirred tank, or airlift bioreactor as the chosen types of fermenters. The exoenzyme lipase adsorbed rapidly and, after separating cells and adsorbents, desorbed in a packed bed column. Up to 85% of the produced lipase were recovered, fractions of these had been concentrated up to the factor 20 and purified up to a factor of 40 by the procedure. By using the airlift bioreactor an enhancement of biomass production was observed, but the necessity of the addition of an anti-foam reagent resulted in higher product losses in adsorption as well as in desorption. Production and adsorption kinetics have been modeled and applied to in situ-adsorption. The model was used to perform a parameter study in which the influence of biological and physical parameters as well as process parameters on discontinuous and continuous in situ-adsorption was investigated. PMID:16267849

  11. Adsorption of laminaribiose in an in-situ product recovery process

    NASA Astrophysics Data System (ADS)

    Waluga, Thomas; Scholl, Stephan

    2012-05-01

    With the decreasing availability of fossil carbon sources new synthesis routes for pharmaceuticals and finechemicals find growing interest. Higher oligosaccharide laminaribiose can be produced by enzymatic synthesis from inexpensive sucrose. For an economic process an in-situ product removal by adsorption is investigated. BEA 50 zeolite shows high potential for application due to its good adsorption properties. Isotherms show Langmuir behavior and adequate loadings of nearly 100 mg ṡ g-1 can be reached. Other intermediates formed during the process do not adsorb on this zeolite or show weaker adsorption. Further thermal desorption can be used to regain laminaribiose. However the use of BEA 50 zeolite needs a sophisticated desorption process because of the zeolites' high acidity which catalyzes the degradation of laminaribiose. Hence lower temperatures have to be used or combined with displacement desorption.

  12. 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

  13. 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

  14. 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. PMID:27148713

  15. 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.

  16. 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

  17. 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. PMID:24922353

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

    PubMed

    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

  19. 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%. PMID:27148730

  20. 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.

  1. 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.

  2. An adsorption-photocatalysis hybrid process using multi-functional-nanoporous materials for wastewater reclamation.

    PubMed

    Vimonses, Vipasiri; Jin, Bo; Chow, Christopher W K; Saint, Christopher

    2010-10-01

    In this study, two of our recently developed laboratory scale wastewater treatment systems, fluidized-bed reactor (FBR) using formulated clay mixture absorbents (clay-FBR adsorption) and an annular slurry photoreactor (ASP) using TiO(2) impregnated kaolin catalysts (TiO(2)-K-ASP) were integrated as an adsorption-photocatalysis hybrid process to treat municipal wastewater as alternative secondary and tertiary treatment for wastewater reclamation. Primary effluent from sewage and secondary effluent from a membrane bioreactor treatment process were used to assess chemical removal capabilities of the FBR and ASP systems, and the hybrid process. The formulated clays-FBR system demonstrated the prevailing removal efficiency toward PO(4)(3-), NO(3)(-) and suspended solids. The TiO(2)-K-ASP showed superior degradation of dissolved organic content; while the presence of inorganic ions caused a detrimental effect on its performance. The integration of the adsorption and degradation system as a hybrid treatment process resulted in a synergetic enhancement for the chemical removal efficiency. Complete elimination of PO(4)(3-) content was obtained in the adsorption stage; while 30% and 65% NO(3)(-) removal were obtained from the hybrid treatment of the primary and secondary effluents, respectively. The corresponding COD reduction during the photodegradation was further investigated by the high-performance size exclusion chromatography technique, where it revealed the shift of apparent molecular weight of the dissolved organic contaminants toward the smaller region. This present study demonstrated that this adsorption-photocatalysis hybrid technology can be used as a feasible alternative treatment process for wastewater reclamation. PMID:20619869

  3. 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.

  4. 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.

  5. An integrated detoxification process with electrodialysis and adsorption from the hemicellulose hydrolysates of yellow poplars.

    PubMed

    Trinh, Ly Thi Phi; Kundu, Chandan; Lee, Jae-Won; Lee, Hong-Joo

    2014-06-01

    An integrated detoxification process with electrodialysis (ED) followed by adsorption was performed to remove fermentation inhibitors from hemicellulose hydrolysates. The hydrolysates were prepared by oxalic acid pretreatment of yellow poplars at different temperatures. Of fermentation inhibitors, acetic acid showed high removal efficiency of about 90% and high transport rate during the ED process without membrane fouling. The integration of the detoxification processes increased up to the ethanol yield of 0.33g/g sugar, the ethanol production of about 9g/L, and the productivity of 0.12g/Lh, while the fermentation of non-detoxified hydrolysates did not produce bioethanol. The influence of inhibitor concentration on the fermentability showed that HMF had the highest inhibition effect. The results clearly showed that an integrated detoxification process with ED followed by adsorption removed fermentation inhibitors with high efficiency and increased the fermentability of the oxalic acid pretreated hemicellulose hydrolysates. PMID:24713602

  6. 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. PMID:22575375

  7. 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. PMID:27003089

  8. 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)

  9. 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.

  10. 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.

  11. Combined adsorption-UF process increases TOC removal

    SciTech Connect

    Chang, Y.J.; Choo, K.H.; Benjamin, M.M.; Reiber, S.

    1998-05-01

    Addition of heated iron oxide particles (HIOPs) as adsorbents to the feedwater of an ultrafiltration (UF) membrane system significantly increased removal of dissolved organic carbon (DOC) and reduced trihalomethane formation potential (THMFP). Treatment by the HIOP-UF process met the TOC removal criteria set by the enhanced coagulation provision of the proposed Disinfectants/Disinfection By-products Rule in all 16 water sources tested, even though those criteria were not met by enhanced coagulation with alum or ferric sulfate in many of the water sources. At pH 6.5 and for the operational conditions studied, 40--75 percent of the DOC was removed; this percentage might be increased at lower pH or a higher HIOP dosage. THMFP was reduced even more (approximately 5--10 percent more) than DOC. Although HIOPs tended to reduce membrane fouling, both soft water with extremely high DOC concentrations and hard, alkaline water with moderate DOC concentrations fouled the HIOP-UF system. Fouling was less severe at lower pH values.

  12. Stability of nitrofuran residues during honey processing and nitrofuran removal by macroporous adsorption resins.

    PubMed

    Jia, Qi; Yu, Shifeng; Cheng, Ni; Wu, Liming; Jia, Jiajia; Xue, Xiaofeng; Cao, Wei

    2014-11-01

    There is increasing concern that the presence of antibiotics such as nitrofurans in animal-derived food products is harmful to human. This study originally assessed the effects of different honey processing steps on the stabilities of four nitrofuran metabolites (3-amino-2-oxazolidone, 1-aminohydantonin, semicarbazide and 3-amino-5-morpholinomethyl-2-oxazolidone). Macroporous adsorption resins (MARs) were evaluated for the removal of these residues. Nitrofuran metabolites were analysed by LC-MS/MS after each processing step. The results revealed that honey processing reduced nitrofuran metabolites in honey and the total loss was from 56.6% to 90.4%. Furthermore, LS-901 was the optimum MAR with adsorption rates of 69.9-91.8% for four metabolites. After removing nitrofuran metabolites, the honey could be safely used as winter feed for honeybees. PMID:24874365

  13. 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. PMID:27498500

  14. 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). PMID:24565877

  15. Color removal from acid and reactive dye solutions by electrocoagulation and electrocoagulation/adsorption processes.

    PubMed

    Bellebia, S; Kacha, S; Bouberka, Z; Bouyakoub, A Z; Derriche, Z

    2009-04-01

    In this study, electrocoagulation of Marine Blue Erionyl MR (acid dye) and electrocoagulation followed by adsorption of Brilliant Blue Levafix E-BRA (reactive dye) from aqueous solutions were investigated, using aluminum electrodes and granular activated carbon (GAC). In the electrocoagulation and adsorption of dyestuff solutions, the effects of current density, loading charge, pH, conductivity, stirring velocity, contact time, and GAC concentration were examined. The optimum conditions for the electrocoagulation process were identified as loading charges 7.46 and 1.49 F/m3, for a maximum abatement of 200 mg/L reactive and acid dye, respectively. The residual reactive dye concentration was completely removed with 700 mg/L GAC. The results of this investigation provide important data for the development of a combined process to remove significant concentrations of recalcitrant dyes from water, using moderate activated carbon energy and aluminum consumption, and thereby lowering the cost of treatment. PMID:19445327

  16. Influence of adsorption and anaerobic granular sludge characteristics on long chain fatty acids inhibition process.

    PubMed

    Palatsi, J; Affes, R; Fernandez, B; Pereira, M A; Alves, M M; Flotats, X

    2012-10-15

    The impact of LCFA adsorption on the methanogenic activity was evaluated in batch assays for two anaerobic granular sludges in the presence and absence of bentonite as synthetic adsorbent. A clear inhibitory effect at an oleate (C18:1) concentration of 0.5 g(C18:1) L(-1) was observed for both sludges. Palmitate (C16:0) was confirmed to be the main intermediate of C18:1 degradation in not adapted sludge and its accumulation was further evidenced by fluorescence staining and microscopy techniques. LCFA inhibition could be decreased by the addition of bentonite, reducing the lag-phase and accelerating the kinetics of LCFA degradation, concluding in the importance of the adsorptive nature of the LCFA inhibitory process. Granule morphology and molecular profiling of predominant microorganisms revealed that biomass adaptation to LCFA could modify the intermediates accumulation profiles and process rates. PMID:22841596

  17. 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. PMID:24702296

  18. 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. PMID:26114274

  19. Application of ultrasonic backscattering for level measurement and process monitoring of expanded-bed adsorption columns.

    PubMed

    Thelen, T V; Mairal, A P; Thorsen, C S; Ramirez, W F

    1997-01-01

    Expanded-bed adsorption is a newly commercialized technique for the purification of proteins from cellular debris in downstream processing. An expanded bed presents the possibility of protein recovery in a single step, eliminating the often costly clarification processing steps such as ultrafiltration, centrifugation, and precipitation. A major obstacle to the successful commercialization of this technology is the inability to accurately monitor and control the bed height in these systems. Fluctuations in the feedstock viscosity are common during normal operation and tend to make the operation and control of expanded beds for biological applications complex and difficult. We develop a level measurement technique based upon ultrasonics. It is shown that this technique has great promise for bed-height measurement in expanded-bed adsorption systems. Furthermore, the bed-height measurement can be used in feedback control strategies for bed-height regulation. The proposed ultrasonic sensor is also capable of monitoring for plugging and bubbling in the column. PMID:9336988

  20. Post-adsorption process of Yb phosphate nano-particle formation by Saccharomyces cerevisiae

    NASA Astrophysics Data System (ADS)

    Jiang, MingYu; Ohnuki, Toshihiko; Tanaka, Kazuya; Kozai, Naofumi; Kamiishi, Eigo; Utsunomiya, Satoshi

    2012-09-01

    In this study, we have investigated the post-adsorption process of ytterbium (Yb) phosphate nano-particle formation by Saccharomyces cerevisiae (yeast). The yeast grown in P-rich medium were exposed to 1.44 × 10-4 mol/L Yb(III) solution for 2-120 h, and 2 months at 25 ± 1 °C at an initial pH of 3, 4, or 5, respectively. Ytterbium concentrations in solutions decreased as a function of exposure time. Field-emission scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (FESEM), transmission electron microscopy (TEM), and synchrotron-based extended X-ray absorption fine structure (EXAFS) analyses revealed that nano-sized blocky Yb phosphate with an amorphous phase formed on the yeast cells surfaces in the solutions with Yb. These nano-sized precipitates that formed on the cell surfaces remained stable even after 2 months of exposure at 25 ± 1 °C around neutral pHs. The EXAFS data revealed that the chemical state of the accumulated Yb on the cell surfaces changed from the adsorption on both phosphate and carboxyl sites at 30 min to Yb phosphate precipitates at 5 days, indicating the Yb-phosphate precipitation as a major post-adsorption process. In addition, the precipitation of Yb phosphate occurred on cell surfaces during 7 days of exposure in Yb-free solution after 2 h of exposure (short-term Yb adsorption) in Yb solution. These results suggest that the released P from the inside of yeast cells reacted with adsorbed Yb on cell surfaces, resulting in the formation of Yb precipitates, even though no P was added to the exposure solution. In an abiotic system, the EXAFS data showed that the speciation of sorbed Yb on the reference materials, carboxymethyl cellulose and Ln resin, did not change even when the Yb was exposed to P solution, without forming Yb phosphate precipitates. This result strongly suggests that the cell surface of the yeast plays an important role in the Yb-phosphate precipitation process, not only as a carrier of the

  1. Diversity of viral photosystem-I psaA genes

    PubMed Central

    Hevroni, Gur; Enav, Hagay; Rohwer, Forest; Béjà, Oded

    2015-01-01

    Marine photosynthesis is one of the major contributors to the global carbon cycle and the world's oxygen supply. This process is largely driven by cyanobacteria, namely Synechococcus and Prochlorococcus. Genes encoding photosystem-II (PSII) reaction center proteins are found in many cyanophage genomes, and are expressed during the infection of their hosts. On the basis of metagenomics, cyanophage photosystem-I (PSI) gene cassettes were recently discovered with two gene arrangements psaJF→C→A→B→K→E→D and psaD→C→A→B. It was suggested that the horizontal transfer of PSII and PSI genes is increasing phage fitness. To better understand their diversity, we designed degenerate primers to cover a wide diversity of organisms, and using PCR we targeted the psaC→A arrangement, which is unique to cyanophages cassettes. We examined viral concentrates from four islands in the Pacific Ocean and found samples containing the psaC→A arrangement. Analyses of the amplified viral psaA gene revealed six subgroups varying in their level of similarity and %G+C content, suggesting that the diversity of cyanophage PSI genes is greater than originally thought. PMID:25535938

  2. 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.

  3. [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. PMID:25350562

  4. 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.

  5. Analysis of the adsorption process and of desiccant cooling systems: A pseudo- steady-state model for coupled heat and mass transfer

    NASA Astrophysics Data System (ADS)

    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.

  6. 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

    2015-02-01

    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. PMID:25448945

  7. 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.

  8. 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.

  9. 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.

  10. 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). PMID:27561502

  11. 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

  12. Extension lifetime for dye-sensitized solar cells through multiple dye adsorption/desorption process

    NASA Astrophysics Data System (ADS)

    Chiang, Yi-Fang; Chen, Ruei-Tang; Shen, Po-Shen; Chen, Peter; Guo, Tzung-Fang

    2013-03-01

    In this study, we propose a novel concept of extending the lifetime of dye-sensitized solar cells (DSCs) and reducing the costs of re-conditioning DSCs by recycling the FTO/TiO2 substrates. The photovoltaic performances of DSCs using substrates with various cycles of dye uptake and rinse off history are tested. The results show that dye adsorption and Voc are significantly increased under multiple dye adsorption/desorption process and resulted in the improvement of power conversion efficiency. Moreover, the dyeing kinetics is faster after multiple recycling processes, which is favorable for the industrial application. With surface analysis and charge transport characteristics, we also demonstrate the optimal functionality of TiO2/dye interface for the improved Voc and efficiency. The results confirm that the improved performances are due to increased dye loading and dense packing of dye molecules. Our results are beneficial for the understanding on the extension of DSCs lifetime after long-term operation in the application of DSC modules. This approach may also be applied in the replacement of newly synthesized photosensitizes to the active cells.

  13. 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.

  14. Radically New Adsorption Cycles for Carbon Dioxide Sequestration

    SciTech Connect

    James A. Ritter; Armin D. Ebner; James A. McIntyre; Steven P. Reynolds; Sarang A. Gadre

    2005-10-11

    In Parts I and II of this project, a rigorous pressure swing adsorption (PSA) process simulator was used to study new, high temperature, PSA cycles, based on the use of a K-promoted HTlc adsorbent and 4- and 5-step (bed) vacuum swing PSA cycles, which were designed to process a typical stack gas effluent at 575 K containing (in vol%) 15 % CO{sub 2}, 75% N{sub 2} and 10% H{sub 2}O into a light product stream depleted of CO{sub 2} and a heavy product stream enriched in CO{sub 2}. Literally, thousands (2,850) of simulations were carried out to the periodic state to study the effects of the light product purge to feed ratio ({gamma}), cycle step time (t{sub s}) or cycle time (t{sub c}), high to low pressure ratio ({pi}{sub T}), and heavy product recycle ratio (R{sub R}) on the process performance, while changing the cycle configuration from 4- to 5-step (bed) designs utilizing combinations of light and heavy reflux steps, two different depressurization modes, and two sets of CO{sub 2}-HTlc mass transfer coefficients. The process performance was judged in terms of the CO{sub 2} purity and recovery, and the feed throughput. The best process performance was obtained from a 5-step (bed) stripping PSA cycle with a light reflux step and a heavy reflux step (with the heavy reflux gas obtained from the low pressure purge step), with a CO{sub 2} purity of 78.9%, a CO{sub 2} recovery of 57.4%, and a throughput of 11.5 L STP/hr/kg. This performance improved substantially when the CO{sub 2}-HTlc adsorption and desorption mass transfer coefficients (uncertain quantities at this time) were increased by factors of five, with a CO{sub 2} purity of 90.3%, a CO{sub 2} recovery of 73.6%, and a throughput of 34.6 L STP/hr/kg. Overall, this preliminary study disclosed the importance of cycle configuration through the heavy and dual reflux concepts, and the importance of knowing well defined mass transfer coefficients to the performance of a high temperature PSA process for CO{sub 2

  15. [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. PMID:20623851

  16. 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.

  17. 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.

  18. Removal of an anionic dye by adsorption/precipitation processes using alkaline white mud.

    PubMed

    Zhu, Mao-Xu; Lee, Li; Wang, Hai-Hua; Wang, Zheng

    2007-11-19

    Alkaline white mud (AWM) has been investigated as a low-cost material for removal of an anionic dye, acid blue 80. The effects of contact time, initial pH of dye solution, AWM dosage, and the presence of inorganic anion sulphate or phosphate ion on removal of the dye were evaluated. The results show that AWM could be used as an effective material for removal of acid blue 80 in a pre or main process, particularly at high dye concentration (>300 mgL(-1)), reaching maximum removal efficiency of 95%. At low dye concentration, surface adsorption is mainly responsible for the dye removal, while chemical precipitation of the dye anions with soluble Ca(2+) and Mg(2+) may play a dominant role for the dye removal at high concentration, producing much less sludge than conventional adsorption method. Solution pH has only a limited effect on the dye removal due to high alkalinity and large pH buffer capacity of AWM suspension and thereby pH is not a limiting factor in pursuing high dye removal. The presence of SO(4)(2-) could reduce the dye removal by AWM only when SO(4)(2-) concentration is beyond 0.7 mmolL(-1). The dye removal may be significantly suppressed by the presence of phosphate with increasing concentration, and the reduction in the dye removal is much larger at high dye concentrations than at low ones. PMID:17532132

  19. 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.

  20. 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.

  1. 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.

  2. 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. PMID:25072139

  3. ARSENIC TREATMENT BY ADSORPTIVE TECHNOLOGY

    EPA Science Inventory

    Presentation will discuss the removal of arsenic from drinking water using the adsorptive media treatment process. Fundamental information is provided on the design and operation of adsorptive media technology including the selection of the adsorptive media. The information cites...

  4. Adsorption and degradation processes of tributyltin and trimethyltin in landfill leachates treated with iron nanoparticles.

    PubMed

    Peeters, Kelly; Lespes, Gaëtane; Milačič, Radmila; Ščančar, Janez

    2015-10-01

    Biotic and abiotic degradation of toxic organotin compounds (OTCs) in landfill leachates is usually not complete. In this work adsorption and degradation processes of tributyltin (TBT) and trimethyltin (TMeT) in leachate sample treated with different iron nanoparticles (FeNPs): Fe(0) (nZVI), FeO and Fe3O4 were investigated to find conditions for their efficient removal. One sample aliquot was kept untreated (pH 8), while to the others (pH 8) FeNPs dispersed with tetramethyl ammonium hydroxide (TMAH) or by mixing were added and samples shaken under aerated conditions for 7 days. The same experiments were done in leachates in which the pH was adjusted to 3 with citric acid. Size distribution of TBT and TMeT between particles >5 µm, 0.45-5 µm, 2.5-0.45 µm, and <2.5 nm was determined by sequential filtration and their concentrations in a given fraction by gas chromatography coupled to inductively coupled plasma mass spectrometry (GC-ICP-MS). Results revealed that most of the TBT or TMeT was present in fractions with particles >2.5 or <2.5 nm, respectively. At pH 8 adsorption of TBT to FeNPs prevailed, while at pH 3, the Fenton reaction provoked degradation of TBT by hydroxyl radicals. TBT was the most effectively removed (96%) when sequential treatment of leachate with nZVI (dispersed by mixing) was applied first at pH 8, followed by nZVI treatment of the aqueous phase, previously acidified to pH 3 with citric acid. Such treatment less effectively removed TMeT (about 40%). It was proven that TMAH provoked methylation of tin, so mixing was recommended for dispersion of nZVI. PMID:26280471

  5. 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

  6. 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...

  7. Effect of single silica gel particle adsorption on the transport processes in a humid air stream

    NASA Astrophysics Data System (ADS)

    Sanyal, Apratim; Basu, Saptarshi; Kumar, Pramod

    2013-11-01

    The effect of adsorption due to a single silica gel particle on a convective field consisting of humid air has been investigated numerically. The adsorption is incorporated as a sink term in the transport equation for species (water vapor) and has been modeled using Linear Driving Force model, while the heat released due to adsorption is taken as source term in the energy equation and proportional to the amount of water vapor adsorbed. The heat released creates a coupling between the species and the temperature field as the adsorption characteristics are directly influenced by particle temperature. The extent of species and temperature boundary layer show the diffusion of the adsorption effects into the free stream. Surface adsorption is found to decrease with Reynolds no. The particle surface temperature increases from forward stagnation point till downstream. This work provides a model for understanding the adsorption kinetics in convective stream for other adsorbate-adsorbent pair. Further more complex scenarios can be modeled such as presence of multiple adsorbent particles, the interaction of species and temperature boundary layers setup due to individual particles and their influence on the overall adsorption characteristics.

  8. 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.

  9. 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. PMID:22648351

  10. Tubular carbon nanotube-based gas diffusion electrode removes persistent organic pollutants by a cyclic adsorption - Electro-Fenton process.

    PubMed

    Roth, Hannah; Gendel, Youri; Buzatu, Pompilia; David, Oana; Wessling, Matthias

    2016-04-15

    We report a novel tubular electrochemical cell which is operated in a cyclic adsorption - electro-Fenton process and by this means overcomes the drawbacks of the traditional electro-Fenton process. A microtube made only of multi-walled carbon nanotubes (MWCNT) functions as a gas diffusion electrode (GDE) and highly porous adsorber. In the process, the pollutants were first removed electroless from the wastewater by adsorption on the MWCNT-GDE. Subsequently, the pollutants are electrochemically degraded in a defined volume of electrolyte solution using the electro-Fenton process. Oxygen was supplied into the lumen of the saturated microtubular GDE which was surrounded by a cylindrical anode made of Ti-felt coated with Pt/IrO2 catalysts. For the proof of concept the model pollutant Acid Red 14 (AR14), an azo dye, was used. The decomposition of AR14 was studied at different applied current densities and initial concentrations of ferrous iron in the electrolyte solution. At optimal conditions, complete regeneration of the adsorption capacity of the MWCNT-GDE, complete decolorization and TOC and COD removal rates of 50% and 70% were achieved, respectively. The MWCNT-GDE is regenerated and again available for adsorption. This approach allows water treatment independent of its composition, thus does not require any addition of chemicals to the wastewater. PMID:26775104

  11. 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

  12. Prostate-Specific Antigen (PSA) Test

    MedlinePlus

    ... What are some of the limitations and potential harms of the PSA test for prostate cancer screening? ... has been learned about both the benefits and harms of prostate cancer screening, a number of organizations ...

  13. 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.

  14. Adsorption and Thermal Processing of Glycolaldehyde, Methyl Formate, and Acetic Acid on Graphite at 20 K.

    PubMed

    Burke, Daren J; Puletti, Fabrizio; Woods, Paul M; Viti, Serena; Slater, Ben; Brown, Wendy A

    2015-07-01

    We present the first detailed comparative study of the adsorption and thermal processing of the three astrophysically important C2O2H4 isomers glycolaldehyde, methyl formate, and acetic acid adsorbed on a graphitic grain analogue at 20 K. The ability of the individual molecule to form intermolecular hydrogen bonds is extremely important, dictating the growth modes of the ice on the surface and the measured desorption energies. Methyl formate forms only weak intermolecular bonds and hence wets the graphite surface, forming monolayer, bilayer, and multilayer ices, with the multilayer having a desorption energy of 35 kJ mol(-1). In contrast, glycolaldehyde and acetic acid dewet the surface, forming clusters even at the very lowest coverages. The strength of the intermolecular hydrogen bonding for glycolaldehyde and acetic acid is reflected in their desorption energies (46.8 and 55 kJ mol(-1), respectively), which are comparable to those measured for other hydrogen-bonded species such as water. Infrared spectra show that all three isomers undergo structural changes as a result of thermal processing. In the case of acetic acid and glycolaldehyde, this can be assigned to the formation of well-ordered, crystalline, structures where the molecules form chains of hydrogen-bonded moieties. The data reported here are of relevance to astrochemical studies of hot cores and star-forming regions and can be used to model desorption from interstellar ices during the warm up phase with particular importance for complex organic molecules. PMID:26057183

  15. Low-Cost Process for Silicon Purification with Bubble Adsorption in Al-Si Melt

    NASA Astrophysics Data System (ADS)

    Yu, Wenzhou; Ma, Wenhui; Lv, Guoqiang; Ren, Yongsheng; Dai, Yongnian; Morita, Kazuki

    2014-08-01

    The primary silicon and Al-Si alloy have been separated in hypereutectic Al-Si melt by the electromagnetic stirring and directional solidification processes. During the electromagnetic separation process, the behavior of a hydrogen bubble in Al-Si melt has been discussed. Furthermore, the bubble adsorption effect for the Si purification has been revealed. The results show that the bubble cavity formed in the lower part of the sample by pulling it up. The scanning electron microscope along with energy dispersive spectrometer (SEM-EDS) analysis indicated that a lot of impurities were adsorbed onto the surface of the bubble cavity that may be beneficial for the Si purification. By decreasing the pulling-up rates, the size of the bubble cavity in Al-Si alloy increased, which results in the decreasing of the impurity contents in primary silicon. In this work, the impurity content in primary silicon is 10.8 ppmw, which is obviously improved compared with the 777.57 ppmw in metallurgical silicon. It is a low-cost technology that will be a potential route for the Si purification.

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

    DOEpatents

    Staiger, Chad L.; Vaughn, Mark R.; Miller, A. Keith; Cornelius, Christopher J.

    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.

  17. 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

  18. 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. PMID:26026127

  19. 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. PMID:26006292

  20. 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. PMID:25617868

  1. Benzene adsorption and the encapsulation processes in SiC nanotubes

    NASA Astrophysics Data System (ADS)

    de Oliveira, J. B.; Baierle, R. J.; Miwa, R. H.

    2012-07-01

    We have performed a theoretical ab initio study of interaction between benzene molecules and silicon carbide nanotubes (SiCNTs). Two different scenarios have been examined, (1) benzene molecules adsorbed on the SiCNT surface, and (2) benzene molecules encapsulated by SiCNTs. In order to provide a more general picture, for both systems we have considered several geometries and nanotube (NT) chiralities. The calculations were performed by using the density functional theory within the local density approximation. The suitability of such choice has been discussed. In (1), we find that the benzene adsorption on the SiCNT is an exothermic process, with binding energies between 0.3 and 0.4 eV/molecule, and in (2) we obtained binding energies of ˜0.6 eV/molecule, revealing a preference for the benzene encapsulated systems. For both cases, we verify that the SiCNTs are more reactive than the carbon nanotubes (CNTs). There are no chemical bonds at the benzene-SiCNT interface, and in (1) we observe that the benzene molecule is attached to the NT surface mediated by π-π stacking interactions, similar to the benzene-CNT systems. On the other hand, we find that the encapsulation of benzene molecules becomes no longer exothermic for SiCNTs with diameters smaller than ˜9 Å. Further investigations indicate a barrierless process for the benzene encapsulation through an open edge of SiCNT. We find attractive forces of ˜0.4 nN, and there is a dependence on the atomic configuration of the open edge on the nanotube.

  2. Biosorption of strontium from simulated nuclear wastewater by Scenedesmus spinosus under culture conditions: adsorption and bioaccumulation processes and models.

    PubMed

    Liu, Mingxue; Dong, Faqin; Kang, Wu; Sun, Shiyong; Wei, Hongfu; Zhang, Wei; Nie, Xiaoqin; Guo, Yuting; Huang, Ting; Liu, Yuanyuan

    2014-06-01

    Algae biosorption is an ideal wastewater treatment method when coupled with algae growth and biosorption. The adsorption and bioaccumulation of strontium from simulated nuclear wastewater by Scenedesmus spinosus were investigated in this research. One hundred mL of cultured S. spinosus cells with a dry weight of 1.0 mg in simulated nuclear wastewater were used to analyze the effects on S. spinosus cell growth as well as the adsorption and bioaccumulation characters under conditions of 25 ± 1 °C with approximately 3,000 lux illumination. The results showed that S. spinosus had a highly selective biosorption capacity for strontium, with a maximum bioremoval ratio of 76%. The adsorbed strontium ion on cell walls was approximately 90% of the total adsorbed amount; the bioaccumulation in the cytoplasm varied by approximately 10%. The adsorption quantity could be described with an equilibrium isotherm. The pseudo-second-order kinetic model suggested that adsorption was the rate-limiting step of the biosorption process. A new bioaccumulation model with three parameters was proposed and could give a good fit with the experiment data. The results suggested that S. spinosus may be a potential biosorbent for the treatment of nuclear wastewater in culture conditions. PMID:24919131

  3. Biosorption of Strontium from Simulated Nuclear Wastewater by Scenedesmus spinosus under Culture Conditions: Adsorption and Bioaccumulation Processes and Models

    PubMed Central

    Liu, Mingxue; Dong, Faqin; Kang, Wu; Sun, Shiyong; Wei, Hongfu; Zhang, Wei; Nie, Xiaoqin; Guo, Yuting; Huang, Ting; Liu, Yuanyuan

    2014-01-01

    Algae biosorption is an ideal wastewater treatment method when coupled with algae growth and biosorption. The adsorption and bioaccumulation of strontium from simulated nuclear wastewater by Scenedesmus spinosus were investigated in this research. One hundred mL of cultured S. spinosus cells with a dry weight of 1.0 mg in simulated nuclear wastewater were used to analyze the effects on S. spinosus cell growth as well as the adsorption and bioaccumulation characters under conditions of 25 ± 1 °C with approximately 3,000 lux illumination. The results showed that S. spinosus had a highly selective biosorption capacity for strontium, with a maximum bioremoval ratio of 76%. The adsorbed strontium ion on cell walls was approximately 90% of the total adsorbed amount; the bioaccumulation in the cytoplasm varied by approximately10%. The adsorption quantity could be described with an equilibrium isotherm. The pseudo-second-order kinetic model suggested that adsorption was the rate-limiting step of the biosorption process. A new bioaccumulation model with three parameters was proposed and could give a good fit with the experiment data. The results suggested that S. spinosus may be a potential biosorbent for the treatment of nuclear wastewater in culture conditions. PMID:24919131

  4. 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

  5. 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). PMID:17969639

  6. Adsorption compared with sulfide precipitation as metal removal processes from acid mine drainage in a constructed wetland

    NASA Astrophysics Data System (ADS)

    Machemer, Steven D.; Wildeman, Thomas R.

    1992-01-01

    Metal removal processes from acid mine drainage were studied in an experimental constructed wetland in the Idaho Springs-Central City mining district of Colorado. The wetland was designed to passively remove heavy metals from the mine drainage flowing from the Big Five Tunnel. Concurrent studies were performed in the field on the waters flowing from the wetland and in the laboratory on the wetland substrate. Both studies suggest that there is competition for organic adsorption sites among Fe, Cu, Zn and Mn. Iron and Cu appear to be more strongly adsorbed than Zn and Mn. The adsorption of metals varies with the fluctuation of pH in the outflow water. Also indicated by field and laboratory studies is the microbial reduction of sulfate with a corresponding increase in the sulfide concentration of the water. As sulfide is generated. Cu and Zn are completely removed. The field results suggest that upon start up of a constructed wetland, the adsorption of dissolved metals onto organic sites in the substrate material will be an important process. Over time, sulfide precipitation becomes the dominant process for metal removal from acid mine drainage.

  7. Organization of photosystem I polypeptides. Identification of PsaB domains that may interact with PsaD.

    PubMed Central

    Xu, Q; Chitnis, P R

    1995-01-01

    PsaA and PsaB are homologous integral membrane-proteins that form the heterodimeric core of photosystem i (PSI). We used subunit-deficient PSI complexes from the mutant strains of the cyanobacterium Synechocystis sp. PCC 6803 to examine interactions between PsaB and other PSI subunits. Incubation of the wild-type PSI with thermolysin yielded 22-kD C-terminal fragments of PsaB that were resistant to further proteolysis. Modification of the wild-type PSI with N-hydroxysuccinimidobiotin and subsequent cleavage by thermolysin showed that the lysyl residues in the 22-kD C-terminal domain were inaccessible to modification by N-hydroxysuccinimidobiotin. The absence of PsaE, PsaF, PsaI, PsaJ, or PsaL facilitated accumulation of 22-kD C-terminal fragments of PsaB but did not alter their resistance to further proteolysis. When the PsaD-less PSI was treated with thermolysin, the 22-kD C-terminal fragments of PsaB were rapidly cleaved, with concomitant accumulation of a 16-kD fragment and then a 3.4-kD one. We mapped the N termini of these fragments by N-terminal amino acid sequencing and the C termini from their positive reaction with an antibody against the C-terminal peptide of PsaB. The cleavage sites were proposed to be in the extramembrane loops on the cytoplasmic side. Western blot analyses showed resistance of PsaC and PsaI to proteolysis prior to cleavage of the 22-kD fragments. Therefore, we propose that PsaD shields two extramembrane loops of PsaB and protects the C-terminal domain of PsaB from in vitro proteolysis. PMID:7630936

  8. Rosetta Planetary Science Archive (PSA) Status

    NASA Astrophysics Data System (ADS)

    Wirth, Kristin R.; Cardesin, A.; Barthelemy, M.; Diaz del Rio, J.; Zender, J.; Arviset, C.

    2006-09-01

    The Planetary Science Archive (PSA) is an online database (accessible via http://www.rssd.esa.int/PSA) implemented by ESA/RSSD. Currently the PSA contains the science data from the Giotto (Halley), Mars Express and SMART-1 (Moon) missions, and the Rosetta Supplementary Archive (Wirtanen). The PSA user is offered a broad range of search possibilities. Search queries can be combined without restrictions and are executed across the whole database. The PSA utilizes the Planetary Data System (PDS) standard. In spring 2007 the PSA will provide the first science and engineering data collected by Rosetta. In preparation for the initial Peer Review to be performed before publication of these data, an Internal Review was held in March 2006, executed by staff internal to the organizations responsible for the Rosetta archiving (ESA, PDS, CNES). The Internal Reviewers identified shortcomings in documentation, data structures, and completeness of the data delivery. They recommended the usage of unified conventions and formats across different instruments. Work is ongoing to include standardized geometry information in the datasets. Rosetta was launched in March 2004 to rendezvous with comet 67P/Churyumov-Gerasimenko (C-G) in May 2014. After having placed a lander on the comet's surface, the Rosetta orbiter will continue to orbit C-G and accompany the comet through perihelion. Rosetta makes use of three Earth swingbys and one Mars swingby in order to reach C-G. Rosetta will also perform close flybys at two asteroids, namely 2867 Steins in September 2008 and 21 Lutetia in July 2010. In addition, Rosetta makes scientific observations of targets of opportunity, e.g. lightcurves of the flyby asteroids to study the rotation, and plasma measurements when passing through cometary ion tails or meteoroid streams. Rosetta continuously monitored the encounter of the Deep Impact probe with comet 9P/Tempel 1 over an extended period of 16 days around the impact on 4 July 2005.

  9. Genetic correction of PSA values using sequence variants associated with PSA levels

    PubMed Central

    Gudmundsson, Julius; Besenbacher, Soren; Sulem, Patrick; Gudbjartsson, Daniel F.; Olafsson, Isleifur; Arinbjarnarson, Sturla; Agnarsson, Bjarni A.; Benediktsdottir, Kristrun R.; Isaksson, Helgi J.; Kostic, Jelena P.; Gudjonsson, Sigurjon A.; Stacey, Simon N.; Gylfason, Arnaldur; Sigurdsson, Asgeir; Holm, Hilma; Bjornsdottir, Unnur S.; Eyjolfsson, Gudmundur I.; Navarrete, Sebastian; Fuertes, Fernando; Garcia-Prats, Maria D.; Polo, Eduardo; Checherita, Ionel A.; Jinga, Mariana; Badea, Paula; Aben, Katja K.; Schalken, Jack A.; van Oort, Inge M.; Sweep, Fred C.; Helfand, Brian T.; Davis, Michael; Donovan, Jenny L.; Hamdy, Freddie C.; Kristjansson, Kristleifur; Gulcher, Jeffrey R.; Masson, Gisli; Kong, Augustine; Catalona, William J.; Mayordomo, Jose I.; Geirsson, Gudmundur; Einarsson, Gudmundur V.; Barkardottir, Rosa B.; Jonsson, Eirikur; Jinga, Viorel; Mates, Dana; Kiemeney, Lambertus A.; Neal, David E.; Thorsteinsdottir, Unnur; Rafnar, Thorunn; Stefansson, Kari

    2013-01-01

    Measuring serum levels of the prostate specific antigen (PSA) is the most common screening method for prostate cancer. However, PSA levels are affected by a number of factors apart from neoplasia. Notably, around 40% of the variability of PSA levels in the general population is accounted for by inherited factors, suggesting that it may be possible to improve both sensitivity and specificity by adjusting test results for genetic effects. In order to search for sequence variants that associate with PSA levels, we performed a genome-wide association study and follow-up analysis using PSA information from 15,757 Icelandic and 454 British men not diagnosed with prostate cancer. Overall, we detected a genome-wide significant association between PSA levels and SNPs at six loci: 5p15.33 (rs2736098), 10q11 (rs10993994), 10q26 (rs10788160), 12q24 (rs11067228), 17q12 (rs4430796), and 19q13.33 (rs17632542 (KLK3: I179T), each with Pcombined < 3×10−10. Among 3,834 men who underwent a biopsy of the prostate, the 10q26, 12q24, and 19q13.33 alleles that associate with high PSA levels are associated with higher probability of a negative biopsy (OR between 1.15 and 1.27). Assessment of association between the 6 loci and prostate cancer risk in 5,325 cases and 41,417 controls from Iceland, the Netherlands, Spain, Romania, and the US showed that the SNPs at 10q26 and 12q24 were exclusively associated with PSA levels, whereas the other 4 loci also were associated with prostate cancer risk. We propose that a personalized PSA cutoff value, based on genotype, should be used when deciding to perform a prostate biopsy. PMID:21160077

  10. Electrostatic influence of PsaC protein binding to the PsaA/PsaB heterodimer in photosystem I.

    PubMed

    Ishikita, Hiroshi; Stehlik, Dietmar; Golbeck, John H; Knapp, Ernst-Walter

    2006-02-01

    The absence of the PsaC subunit in the photosystem I (PSI) complex (native PSI complex) by mutagenesis or chemical manipulation yields a PSI core (P700-F(X) core) that also lacks subunits PsaD and PsaE and the two iron-sulfur clusters F(A) and F(B), which constitute an integral part of PsaC. In this P700-F(X) core, the redox potentials (E(m)) of the two quinones A(1A/B) and the iron-sulfur cluster F(X) as well as the corresponding protonation patterns are investigated by evaluating the electrostatic energies from the solution of the linearized Poisson-Boltzmann equation. The B-side specific Asp-B558 changes its protonation state significantly upon isolating the P700-F(X) core, being mainly protonated in the native PSI complex but ionized in the P700-F(X) core. In the P700-F(X) core, E(m)(A(1A/B)) remains practically unchanged, whereas E(m)(F(X)) is upshifted by 42 mV. With these calculated E(m) values, the electron transfer rate from A(1) to F(X) in the P700-F(X) core is estimated to be slightly faster on the A(1A) side than that of the wild type, which is consistent with kinetic measurements. PMID:16258043

  11. 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.

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

    PubMed Central

    McJimpsey, Erica L.

    2016-01-01

    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. PMID:26911983

  13. Prostate-specific antigen (PSA) blood test

    MedlinePlus

    Prostate-specific antigen; Prostate cancer screening test ... 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 ...

  14. 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%). PMID:26471519

  15. 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.

  16. 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. PMID:19577363

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

    PubMed

    Ettelaie, Rammile; Murray, Brent

    2014-05-28

    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. PMID:24880317

  18. 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.

  19. 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. PMID:27179953

  20. 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.

  1. Building an information model (with the help of PSL/PSA). [Problem Statement Language/Problem Statement Analyzer

    NASA Technical Reports Server (NTRS)

    Callender, E. D.; Farny, A. M.

    1983-01-01

    Problem Statement Language/Problem Statement Analyzer (PSL/PSA) applications, which were once a one-step process in which product system information was immediately translated into PSL statements, have in light of experience been shown to result in inconsistent representations. These shortcomings have prompted the development of an intermediate step, designated the Product System Information Model (PSIM), which provides a basis for the mutual understanding of customer terminology and the formal, conceptual representation of that product system in a PSA data base. The PSIM is initially captured as a paper diagram, followed by formal capture in the PSL/PSA data base.

  2. 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.

  3. The DnaJ-Like Zinc Finger Domain Protein PSA2 Affects Light Acclimation and Chloroplast Development in Arabidopsis thaliana.

    PubMed

    Wang, Yan-Wen; Chen, Si-Ming; Wang, Wei-Jie; Huang, Xing-Qi; Zhou, Chang-Fang; Zhuang, Zhong; Lu, Shan

    2016-01-01

    The biosynthesis of chlorophylls and carotenoids and the assembly of thylakoid membranes are critical for the photoautotrophic growth of plants. Different factors are involved in these two processes. In recent years, members of the DnaJ-like zinc finger domain proteins have been found to take part in the biogenesis and/or the maintenance of plastids. One member of this family of proteins, PSA2, was recently found to localize to the thylakoid lumen and regulate the accumulation of photosystem I. In this study, we report that the silencing of PSA2 in Arabidopsis thaliana resulted in variegated leaves and retarded growth. Although both chlorophylls and total carotenoids decreased in the psa2 mutant, violaxanthin, and zeaxanthin accumulated in the mutant seedlings grown under growth condition. Lower levels of non-photochemical quenching and electron transport rate were also found in the psa2 mutant seedlings under growth condition compared with those of the wild-type plants, indicating an impaired capability to acclimate to normal light irradiance when PSA2 was silenced. Moreover, we also observed an abnormal assembly of grana thylakoids and poorly developed stroma thylakoids in psa2 chloroplasts. Taken together, our results demonstrate that PSA2 is a member of the DnaJ-like zinc finger domain protein family that affects light acclimation and chloroplast development. PMID:27047527

  4. A Nucleus-Encoded Chloroplast Phosphoprotein Governs Expression of the Photosystem I Subunit PsaC in Chlamydomonas reinhardtii.

    PubMed

    Douchi, Damien; Qu, Yujiao; Longoni, Paolo; Legendre-Lefebvre, Linnka; Johnson, Xenie; Schmitz-Linneweber, Christian; Goldschmidt-Clermont, Michel

    2016-05-01

    The nucleo-cytoplasmic compartment exerts anterograde control on chloroplast gene expression through numerous proteins that intervene at posttranscriptional steps. Here, we show that the maturation of psaC mutant (mac1) of Chlamydomonas reinhardtii is defective in photosystem I and fails to accumulate psaC mRNA. The MAC1 locus encodes a member of the Half-A-Tetratricopeptide (HAT) family of super-helical repeat proteins, some of which are involved in RNA transactions. The Mac1 protein localizes to the chloroplast in the soluble fraction. MAC1 acts through the 5' untranslated region of psaC transcripts and is required for their stability. Small RNAs that map to the 5'end of psaC RNA in the wild type but not in the mac1 mutant are inferred to represent footprints of MAC1-dependent protein binding, and Mac1 expressed in bacteria binds RNA in vitro. A coordinate response to iron deficiency, which leads to dismantling of the photosynthetic electron transfer chain and in particular of photosystem I, also causes a decrease of Mac1. Overexpression of Mac1 leads to a parallel increase in psaC mRNA but not in PsaC protein, suggesting that Mac1 may be limiting for psaC mRNA accumulation but that other processes regulate protein accumulation. Furthermore, Mac 1 is differentially phosphorylated in response to iron availability and to conditions that alter the redox balance of the electron transfer chain. PMID:27113776

  5. The DnaJ-Like Zinc Finger Domain Protein PSA2 Affects Light Acclimation and Chloroplast Development in Arabidopsis thaliana

    PubMed Central

    Wang, Yan-Wen; Chen, Si-Ming; Wang, Wei-Jie; Huang, Xing-Qi; Zhou, Chang-Fang; Zhuang, Zhong; Lu, Shan

    2016-01-01

    The biosynthesis of chlorophylls and carotenoids and the assembly of thylakoid membranes are critical for the photoautotrophic growth of plants. Different factors are involved in these two processes. In recent years, members of the DnaJ-like zinc finger domain proteins have been found to take part in the biogenesis and/or the maintenance of plastids. One member of this family of proteins, PSA2, was recently found to localize to the thylakoid lumen and regulate the accumulation of photosystem I. In this study, we report that the silencing of PSA2 in Arabidopsis thaliana resulted in variegated leaves and retarded growth. Although both chlorophylls and total carotenoids decreased in the psa2 mutant, violaxanthin, and zeaxanthin accumulated in the mutant seedlings grown under growth condition. Lower levels of non-photochemical quenching and electron transport rate were also found in the psa2 mutant seedlings under growth condition compared with those of the wild-type plants, indicating an impaired capability to acclimate to normal light irradiance when PSA2 was silenced. Moreover, we also observed an abnormal assembly of grana thylakoids and poorly developed stroma thylakoids in psa2 chloroplasts. Taken together, our results demonstrate that PSA2 is a member of the DnaJ-like zinc finger domain protein family that affects light acclimation and chloroplast development. PMID:27047527

  6. van der Waals corrected DFT simulation of adsorption processes on transition-metal surfaces: Xe and graphene on Ni(111)

    NASA Astrophysics Data System (ADS)

    Silvestrelli, Pier Luigi; Ambrosetti, Alberto

    2015-05-01

    The DFT/vdW-WF2s1 method, recently developed to include the van der Waals interactions in the density functional theory and describe adsorption processes on metal surfaces by taking metal-screening effects into account, is applied to the case of the interaction of Xe and graphene with a transition-metal surface, namely, Ni(111). In general, the adsorption of rare-gas atoms on metal surfaces is important because it is prototypical for physisorption processes. Moreover, the interaction of graphene with Ni(111) is of great interest for practical applications, for instance concerning the efficient and large-scale production of high-quality graphene; from a theoretical point of view, it is particularly challenging, since it can be described by a delicate interplay between chemisorption and physisorption processes. The first-principles simulation of transition metals requires particular care also because they can be viewed as intermediate systems between simple metals and insulating crystals. Even in these cases the method performs well as demonstrated by comparing our results with available experimental data and other theoretical investigations. We confirm that the rare-gas Xe atom is preferentially adsorbed on the top-site configuration on the Ni(111) surface too. Our approach, based on the use of the maximally localized Wannier functions, also allow us to well characterize the bonds between graphene and Ni(111).

  7. 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. PMID:26878687

  8. 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. PMID:21907388

  9. Research on the treatment of liquid waste containing cesium by an adsorption-microfiltration process with potassium zinc hexacyanoferrate.

    PubMed

    Zhang, Chang-Ping; Gu, Ping; Zhao, Jun; Zhang, Dong; Deng, Yue

    2009-08-15

    The removal of cesium from an aqueous solution by an adsorption-microfiltration (AMF) process was investigated in jar tests and lab-scale tests. The adsorbent was K(2)Zn(3)[Fe(CN)(6)](2). The obtained cesium data in the jar test fit a Freundlich-type isotherm well. In the lab-scale test, the mean cesium concentration of the raw water and the effluent were 106.87 microg/L and 0.59 microg/L, respectively, the mean removal of cesium was 99.44%, and the mean decontamination factors (DF) and concentration factors (CF) were 208 and 539, respectively. The removal of cesium in the lab-scale test was better than that in the jar test because the old adsorbents remaining in the reactor still had adsorption capacity with the premise of no significant desorption being observed, and the continuous renewal of the adsorbent surface improved the adsorption capacity of the adsorbent. Some of the suspended solids were deposited on the bottom of the reactor, which would affect the mixing of adsorbents with the raw water and the renewing of the adsorbent surface. Membrane fouling was the main physical fouling mechanism, and the cake layer was the main filtration resistance. Specific flux (SF) decreased step by step during the whole period of operation due to membrane fouling and concentration polarization. The quality of the effluent was good and the turbidity remained lower than 0.1NTU, and the toxic anion, CN(-), could not be detected because of its low concentration, this indicated that the effluent was safe. The AMF process was feasible for practical application in the treatment of liquid waste containing cesium. PMID:19250747

  10. Interaction of bisphenol A with dissolved organic matter in extractive and adsorptive removal processes.

    PubMed

    Zhu, Fei-Die; Choo, Kwang-Ho; Chang, Hyun-Shik; Lee, Byunghwan

    2012-05-01

    The fate of endocrine disrupting chemicals (EDCs) in natural and engineered systems is complicated due to their interactions with various water constituents. This study investigated the interaction of bisphenol A (BPA) with dissolved organic matter (DOM) and colloids present in surface water and secondary effluent as well as its adsorptive removal by powdered activated carbons. The solid phase micro-extraction (SPME) method followed by thermal desorption and gas chromatography-mass spectrometry (GC-MS) was utilized for determining the distribution of BPA molecules in water. The BPA removal by SPME decreased with the increased DOM content, where the formation of BPA-DOM complexes in an aqueous matrix was responsible for the reduced extraction of BPA. Colloidal particles in water samples sorbed BPA leading to the marked reduction of liquid phase BPA. BPA-DOM complexes had a negative impact on the adsorptive removal of BPA by powered activated carbons. The complex formation was characterized based on Fourier transform infrared (FTIR) and ultraviolet-visible (UV-Vis) spectroscopy, along with the calculation of molecular interactions between BPA and functional groups in DOM. It was found that the hydrogen bonding between DOM and BPA would be preferred over aromatic interactions. A pseudo-equilibrium molecular coordination model for the complexation between a BPA molecule and a hydroxyl group of the DOM was developed, which enabled estimation of the maximum sorption site and complex formation constant as well as prediction of organic complexes at various DOM levels. PMID:22330311

  11. 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.

  12. Elucidation of adsorption processes at the surface of Pt(331) model electrocatalysts in acidic aqueous media.

    PubMed

    Pohl, Marcus D; Colic, Viktor; Scieszka, Daniel; Bandarenka, Aliaksandr S

    2016-04-20

    The Pt(331) surface has long been known to be the most active pure metal electrocatalyst for the oxygen reduction reaction (ORR) in acidic media. Its activity is often higher than those known for the Pt-based alloys towards ORR, being comparable with the most active Pt3Ni(111), Pt3Y or Pt5Gd, and being more active than e.g. polycrystalline Pt3Ni. Multiple active sites at this surface offer adsorption energies which are close to the optimal binding energy with respect to the main ORR intermediates; nevertheless, the exact location of these sites is still not clear. Taking into account the unique surface geometry of Pt(331), some adsorbates (including some oxygenated ORR-intermediates) should also contribute to the electronic structure of the neighbouring catalytic centres. However, the experimental elucidation of the specific adsorption of oxygenated species at this surface appears to be a non-trivial task. Such information holds the keys to the understanding of the high activity of this material and would enable the rational design of nanostructured ORR catalysts even without alloying. In this work, the electrified Pt(331)/electrolyte interface has been characterised using cyclic voltammetry (CV) combined with potentiodynamic electrochemical impedance spectroscopy (PDEIS) in 0.1 M HClO4 solutions. The systems were studied in the potential region between 0.05 V and 1.0 V vs. RHE, where the adsorption of *H, *OH and *O species is possible in both O2-free and O2-saturated electrolytes. Our CV and PDEIS results support the hypothesis that in contrast to Pt(111), many Pt(331) surface sites are likely blocked by *O species at the polymer electrolyte membrane fuel cell benchmark potential of 0.9 V (RHE). We propose a model illustrated by simplified adsorbate structures at different electrode potentials, which is, however, able to explain the voltammetric and impedance data, and which is in good agreement with previously reported electrocatalytic measurements. PMID

  13. 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

  14. Clinical performance of serum [-2]proPSA derivatives, %p2PSA and PHI, in the detection and management of prostate cancer

    PubMed Central

    Huang, Ya-Qiang; Sun, Tong; Zhong, Wei-De; Wu, Chin-Lee

    2014-01-01

    Prostate-specific antigen (PSA) has been widely used as a serum marker for prostate cancer (PCa) screening or progression monitoring, which dramatically increased rate of early detection while significantly reduced PCa-specific mortality. However, a number of limitations of PSA have been noticed. Low specificity of PSA may lead to overtreatment in men who presenting with a total PSA (tPSA) level of < 10 ng/mL. As a type of free PSA (fPSA), [-2]proPSA is differentially expressed in peripheral zone of prostate gland and found to be elevated in serum of men with PCa. Two p2PSA-based derivatives, prostate health index (PHI) and %p2PSA, which were defined as [(p2PSA/fPSA) × √ tPSA] and [(p2PSA/fPSA) × 100] respectively, have been suggested to be increased in PCa and can better distinguish PCa from benign prostatic diseases than tPSA or fPSA. We performed a systematic review of the available scientific evidences to evaluate the potentials of %p2PSA and PHI in clinical application. Mounting evidences suggested that both %p2PSA and PHI possess higher area under the ROC curve (AUC) and better specificity at a high sensitivity for PCa detection when compare with tPSA and %fPSA. It indicated that measurements of %p2PSA and PHI significantly improved the accuracy of PCa detection and diminished unnecessary biopsies. Furthermore, elevations of %p2PSA and PHI are related to more aggressive diseases. %p2PSA and PHI might be helpful in reducing overtreatment on indolent cases or assessing the progression of PCa in men who undergo active surveillance. Further studies are needed before being applied in routine clinical practice. PMID:25606581

  15. ZnS Thin Films Deposited by a Spin Successive Ionic Layer Adsorption and Reaction Process

    SciTech Connect

    Han, Seungyeol; Lee, D. H.; Ryu, S. O.; Chang, Chih-hung

    2010-05-20

    In this article, we reported a spin successive ionic layer adsorption and reaction (SILAR) method for the first time. ZnS thin films were deposited by spin SILAR using ZnCl2 and Na2S aqueous precursor solutions at room temperature and atmosphere pressure. The optical, structural, and morphological characterizations of the films were studied by scanning electron microscopy, atomic force microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and UV/visible spectroscopy. Smooth (average roughness <3 nm), uniform, and highly transparent ZnS (transmittance of over 90% in the visible band) thin films could be successfully deposited using this technique with shorter cycle time and much less solvent usage.

  16. A comparative study of using in-line near-infrared spectra, ultraviolet spectra and fused spectra to monitor Panax notoginseng adsorption process.

    PubMed

    Jiang, Cheng; Qu, Haibin

    2015-01-01

    The step of enriching and purifying saponins by macroporous resin column chromatography is closely related to the safety and efficacy of Panax notoginseng products during their manufacturing processes. Adsorption process is one of the most critical unit operations within each chromatographic cycle. In order to understand the adsorption process directly, it is necessary to develop a rapid and precise method to monitor the adsorption process in real time. In this study, comparative evaluation of using near-infrared (NIR) spectra, ultraviolet (UV) spectra and fused spectra to monitor the adsorption process of P. notoginseng was conducted. The uninformative variable elimination by partial least squares (UVE-PLS) regression models were established for quantification of notoginsenoside R1, ginsenoside Rg1, ginsenoside Re, ginsenoside Rb1 and ginsenoside Rd in effluents based on different spectra. There was a significant improvement provided by the models based on fused spectra. The results in this work were conducive to solving the problems about real-time quantitative analysis of saponins during P. notoginseng adsorption. The fusion method of NIR and UV spectra combined with UVE-PLS regression could be a promising strategy to real-time analyze the components, which are difficult to be quantified by individual spectroscopic technique. PMID:25255448

  17. 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.

  18. 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. PMID:24461825

  19. A chemical lift-off process: removing non-specific adsorption in an electrochemical Epstein-Barr virus immunoassay.

    PubMed

    Stratmann, Lutz; Gebala, Magdalena; Schuhmann, Wolfgang

    2013-07-22

    Upon contact of sensor surfaces with complex biological samples containing a variety of different proteins, non-specific adsorption hampers the high-sensitive detection of the analyte in question. To substantially decrease the impact of non-specific adsorption at thiol-based self-assembled monolayers, a chemical lift-off process is introduced. A sequence of local hydrolysis of isooctyl 3-mercaptopropionate, covalent binding of an antigen against the Epstein-Barr virus (EBV), stepwise incubation with a serum sample possibly containing the EBV antibody and an enzyme-labeled anti-human antibody is completed with a lift-off by integral hydrolysis of the remaining ester groups at the self-assembled monolayer. The cleavage of the ester removes any non-specifically bound protein during a following stringent washing step. The substantial improvement of the detection limit of an electrochemical immunoassay against EBV using native recombinant antigens, their immobilization after local deprotection using a scanning electrochemical microscope (SECM) and the local read-out using the generator-collector mode of SECM with redox cycling amplification demonstrates the successful application of the proposed lift-off procedure. PMID:23681905

  20. 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.

  1. Removal of petroleum hydrocarbons from contaminated groundwater by the combined technique of adsorption onto perlite followed by the O3/H2O2 process.

    PubMed

    Moussavi, Gholamreza; Bagheri, Amir

    2012-09-01

    Groundwater contaminated with petroleum hydrocarbons was treated using a combined system of adsorption onto powdered expanded perlite (PEP) followed by the O3/H2O2 process. The pretreatment investigations indicated a high capacity for PEP to remove petroleum hydrocarbons from the contaminated water. An experimental total petroleum hydrocarbon (TPH) adsorption capacity of 275 mg/g PEP was obtained at the natural pH of water. The experimental data fit best with the Freundlich isotherm model and pseudo-second-order adsorption model. The second phase of the experiment evaluated the performance of the O3/H2O2 process in the removal of residual TPH from pretreated water and compared the results with that of raw water. The O3/H202 process attained a maximum TPH removal rate for the pretreated water after 70 min, when 93% of the residual TPH in the effluent of the adsorption system was removed. Overall, the combination of adsorption onto PEP for 100 min and the subsequent treatment with the O3/H2O2 process for 70min eliminated over 99% of the TPH of highly petroleum-contaminated groundwater, with initial values of 162 mg/L. Therefore, we can conclude that the developed treatment system is an appropriate method of remediation for petroleum-contaminated waters. PMID:23240183

  2. Evaluating the Phoenix Definition of Biochemical Failure After {sup 125}I Prostate Brachytherapy: Can PSA Kinetics Distinguish PSA Failures From PSA Bounces?

    SciTech Connect

    Thompson, Anna; Keyes, Mira; Pickles, Tom

    2010-10-01

    Purpose: To evaluate the prostate-specific antigen (PSA) kinetics of PSA failure (PSAf) and PSA bounce (PSAb) after permanent {sup 125}I prostate brachytherapy (PB). Methods and Materials: The study included 1,006 consecutive low and 'low tier' intermediate-risk patients treated with {sup 125}I PB, with a potential minimum follow-up of 4 years. Patients who met the Phoenix definition of biochemical failure (nadir + 2 ng/mL{sup -1}) were identified. If the PSA subsequently fell to {<=}0.5 ng/mL{sup -1}without intervention, this was considered a PSAb. All others were scored as true PSAf. Patient, tumor and dosimetric characteristics were compared between groups using the chi-square test and analysis of variance to evaluate factors associated with PSAf or PSAb. Results: Median follow-up was 54 months. Of the 1,006 men, 57 patients triggered the Phoenix definition of PSA failure, 32 (56%) were true PSAf, and 25 PSAb (44%). The median time to trigger nadir + 2 was 20.6 months (range, 6-36) vs. 49 mo (range, 12-83) for PSAb vs. PSAf groups (p < 0.001). The PSAb patients were significantly younger (p < 0.0001), had shorter time to reach the nadir (median 6 vs. 11.5 months, p = 0.001) and had a shorter PSA doubling time (p = 0.05). Men younger than age 70 who trigger nadir +2 PSA failure within 38 months of implant have an 80% likelihood of having PSAb and 20% chance of PSAf. Conclusions: With adequate follow-up, 44% of PSA failures by the Phoenix definition in our cohort were found to be benign PSA bounces. Our study reinforces the need for adequate follow-up when reporting PB PSA outcomes, to ensure accurate estimates of treatment efficacy and to avoid unnecessary secondary interventions.

  3. 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.

  4. 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).

  5. I. Gas adsorption properties and porosity of transition metal-based cyanogels. II. Novel energy transfer processes in organic light-emitting devices

    NASA Astrophysics Data System (ADS)

    Deshpande, Rahul Shrikant

    The gas adsorption properties and porosity of cyanide-bridged transition metal-based gels are investigated in the first part of this dissertation. The cyanide bridges, connecting two transition metal centers, are characteristic of these gels; hence, these gels are termed cyanogels. Aerogel versus xerogel structures have a profound effect, both, on the thermodynamics and kinetics of gas adsorption on these cyanogels. Carbon dioxide is selectively adsorbed on palladium-cobalt-based cyanogels; the adsorption is fully reversible on both types of gels discussed. The thermodynamics and kinetics of the gas adsorption processes on these gels are analyzed here. From the ease and reproducibility of the CO2 desorption and the associated enthalpy values, it is concluded that CO2 is physisorbed on these gels. Both the adsorption and desorption processes are first-order in the gels. Adsorption of carbon monoxide on the palladium-cobalt cyanogels is also investigated. Unlike CO 2 physisorption, carbon monoxide is chemisorbed on these gels. An uptake of CO brings about a profound change in the xerogel morphology. The palladium-cobalt-based aerogels possess both micro- and mesoporosity; the xerogels are predominantly microporous with a narrow microporosity. The aerogel surfaces are found to be fractal as analyzed by gas adsorption. Unlike the aerogels, the xerogels do not possess surface fractality. The mechanism of adsorption of different gases on these gels is analyzed based on the gel morphologies. These transition metal-based gels are promising for a variety of applications such as heterogeneous catalysts, gas filters and magnetic materials. The porosity of these gels can be exploited to make gel-embedded filters to separate mixtures of gases based on the their differential adsorption propensities. The reversible adsorption of CO2 can be harnessed practically by using these gels as CO2 storage reservoirs. In the second part of this dissertation, the first, balanced, white

  6. 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.

  7. 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

  8. Nuclear power and probabilistic safety assessment (PSA): past through future applications

    NASA Astrophysics Data System (ADS)

    Stamatelatos, M. G.; Moieni, P.; Everline, C. J.

    1995-03-01

    Nuclear power reactor safety in the United States is about to enter a new era -- an era of risk- based management and risk-based regulation. First, there was the age of `prescribed safety assessment,' during which a series of design-basis accidents in eight categories of severity, or classes, were postulated and analyzed. Toward the end of that era, it was recognized that `Class 9,' or `beyond design basis,' accidents would need special attention because of the potentially severe health and financial consequences of these accidents. The accident at Three Mile Island showed that sequences of low-consequence, high-frequency events and human errors can be much more risk dominant than the Class 9 accidents. A different form of safety assessment, PSA, emerged and began to gain ground against the deterministic safety establishment. Eventually, this led to the current regulatory requirements for individual plant examinations (IPEs). The IPEs can serve as a basis for risk-based regulation and management, a concept that may ultimately transform the U.S. regulatory process from its traditional deterministic foundations to a process predicated upon PSA. Beyond the possibility of a regulatory environment predicated upon PSA lies the possibility of using PSA as the foundation for managing daily nuclear power plant operations.

  9. 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)

  10. Hybrid adsorptive membrane reactor

    DOEpatents

    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.

  11. 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.

  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. PMID:23532534

  13. 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...

  14. Antibacterial activity of essential oils mixture against PSA.

    PubMed

    Vavala, Elisabetta; Passariello, Claudio; Pepi, Federico; Colone, Marisa; Garzoli, Stefania; Ragno, Rino; Pirolli, Adele; Stringaro, Annarita; Angiolella, Letizia

    2016-01-01

    Pseudomonas syringae pv. actinidiae (PSA) is the causal agent of bacterial canker of kiwifruit. It is very difficult to treat pandemic disease. The prolonged treatment with antibiotics, has resulted in failure and resistance and alternatives to conventional antimicrobial therapy are needed. The aim of our study was to analyse the phenotypic characteristics of PSA, identify new substances from natural source i.e. essential oils (EOs) able to contain the kiwifruit canker and investigate their potential use when utilised in combination. Specially, we investigated the morphological differences of PSA isolates by scanning electron microscope, and the synergic action of different EOs by time-kill and checkerboard methods. Our results demonstrated that PSA was able to produce extracellular polysaccharides when it was isolated from trunk, and, for the first time, that it was possible to kill PSA with a mixture of EOs after 1 h of exposition. We hypothesise on its potential use in agriculture. PMID:25782920

  15. Point-of-care PSA testing: an evaluation of PSAwatch.

    PubMed

    Karim, O; Rao, A; Emberton, M; Cochrane, D; Partridge, M; Edwards, P; Walker, I; Davidson, I

    2007-01-01

    We present a new quantitative prostate-specific antigen (PSA) assay using a portable, point-of-care test (PSAwatch) and reader system (BioScan) for measuring PSA concentrations in the range from 0.5 to < or =25 microg/l. Blood samples from patients (n=199) were submitted for laboratory PSA and also evaluated using PSAwatch and the BioScan system. PSA concentrations in 188 men were < or =25 microg/l and studied. Correlation between the two methods was good (R(2)=0.88) with a standard error of 1.588. The regression line had a bias of -0.02 at the concentration of 4.00 microg/l. This is the first report of a quantitative, portable, point-of-care PSA test and reader system. PSAwatch may reduce the number of hospital visits for patients with prostate disease. PMID:17353914

  16. Iron modified bentonite: Enhanced adsorption performance for organic pollutant and its regeneration by heterogeneous visible light photo-Fenton process at circumneutral pH.

    PubMed

    Gao, Yaowen; Guo, Yongzhao; Zhang, Hui

    2016-01-25

    Iron modified bentonite (FeMB) was prepared and used as an inexpensive adsorbent to rapidly remove organic pollutant (Rhodamine B, RhB) from aqueous solution. The iron modification significantly improved the adsorption performance of FeMB for RhB and permitted an easy separation of FeMB from the treated effluent. The equilibrium adsorption studies indicated that the dye molecules obeyed Langmuir type of adsorption with the calculated maximum adsorption capacity of 168.13 mg g(-1) for FeMB. The heterogeneous photo-Fenton process operated at circumneutral pH in the presence of visible light irradiation was found to be effective for the regeneration of the spent FeMB. Furthermore, the regeneration efficiency of as high as 79% was still achieved after 5 consecutive adsorption-regeneration cycles. Considering that, the visible light photo-Fenton approach could be applied as an excellent alternative for regenerating clay-based adsorbents by avoiding the use of dissolved iron salts. PMID:26448496

  17. 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

  18. Arraying prostate specific antigen PSA and Fab anti-PSA using light-assisted molecular immobilization technology

    PubMed Central

    Parracino, Antonietta; Neves-Petersen, Maria Teresa; di Gennaro, Ane Kold; Pettersson, Kim; Lövgren, Timo; Petersen, Steffen B

    2010-01-01

    We here report for the first time the creation of prostate specific antigen (PSA) and Fab anti-PSA biosensor arrays using UV light-assisted molecular immobilization (LAMI), aiming at the detection and quantification of PSA, a cancer marker. The technology involves formation of free, reactive thiol groups upon UV excitation of protein aromatic residues located in spatial proximity of disulphide bridges, a conserved structural feature in both PSA and Fab molecules. The created thiol groups bind onto thiol reactive surfaces leading to oriented covalent protein immobilization. Protein activity was confirmed carrying out immunoassays: immobilized PSA was recognized by Fab anti-PSA in solution and immobilized Fab anti-PSA cross-reacted with PSA in solution. LAMI technology proved successful in immobilizing biomedically relevant molecules while preserving their activity, highlighting that insight into how light interacts with biomolecules may lead to new biophotonic technologies. Our work focused on the application of our new engineering principles to the design, analysis, construction, and manipulation of biological systems, and on the discovery and application of new engineering principles inspired by the properties of biological systems. PMID:20665692

  19. 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. PMID:25001042

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

    PubMed

    Chang, Yu; Yang, Zhen-Guo

    2016-06-01

    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. PMID:27171553

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

    PubMed

    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

  2. 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

  3. 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...

  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. PMID:25185390

  6. 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

    Seo, Young-Soo; Satija, Sushil K.; Majewski, Jaroslaw; Sasaki, Darryl Yoshio; Kent, Michael Stuart; Yim, Hyun

    2005-05-01

    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

  7. 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

  8. Association of Polymorphisms in the Prostate-Specific Antigen (PSA) Gene Promoter with Serum PSA Level and PSA Changes after Dutasteride Treatment in Korean Men with Benign Prostatic Hypertrophy

    PubMed Central

    Park, Sung Woon; Kim, Chul Sung

    2010-01-01

    Purpose Studies of genetic variation in the prostate-specific antigen (PSA) gene have improved the diagnostic accuracy of PSA for diagnosing prostate diseases in Caucasians. However, the reference ranges and pharmacokinetics of PSA differ significantly according to race. Therefore, we evaluated the association between genetic variations in the PSA promoter area and benign prostatic hyperplasia (BPH) phenotypes in Korean BPH patients. Materials and Methods One hundred twenty-one men were enrolled. The initial serum PSA level, prostate size, and PSA changes at 3 months after treatment with dutasteride were determined. We amplified the promoter region of the PSA gene (nucleotide positions -158 to -356 and -5217 to -5429) and sequenced the products. Results Three relatively well characterized single-nucleotide polymorphisms (SNPs; rs3760722, rs266867, and rs266868), six uncharacterized SNPs (rs17554958, rs266882, rs4802754, rs2739448, rs2569733, and rs17526278), and one novel SNP (nucleotide position -5402) were found. There were no statistically significant correlations between any of the SNPs of the PSA promoter area and age-adjusted prostate sizes, initial PSA levels, or PSA variations after 3 months of dutasteride treatment. Conclusions SNPs in the PSA promoter area were not associated with BPH phenotypes. We could not predict serum PSA changes after dutasteride treatment on the basis of PSA promoter genotype in Korean patients with BPH. PMID:21221201

  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. PMID:26476049

  10. 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.

  11. 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.

  12. 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

  13. Removal of anionic azo dye from aqueous solution via an adsorption-photosensitized regeneration process on a TiO2 surface.

    PubMed

    Bao, Nan; Li, Yuan; Yu, Xiao-Hong; Niu, Jun-Jian; Wu, Guo-Lin; Xu, Xiao-Hong

    2013-02-01

    Textile dye effluents are typically characterized by strong color and recalcitrance, even at very low concentration. The process of enrichment of anionic azo dye on the surface of TiO(2) fibers followed by photosensitization degradation under ambient air conditions was extensively investigated. Adsorption isotherms and zeta potentials were used to describe the "dye/TiO(2) surface" interface, taking into account the effects of pH on the nature and population of the surface groups on the TiO(2) fibers. The extent of the photocatalytic degradation of dye on TiO(2) surface was determined by FTIR. N(2) adsorption isotherms and optical spectra were employed to investigate the effect of photosensitization. The adsorption of dyes on the TiO(2) surface occurs via electrostatic attraction through the formation of single- or multidentate-coordinated surface complexes. Almost complete photobleaching of the absorption band at 534 nm is achieved in ~4 h. Dye-sensitized TiO(2) fiber could absorb part of the visible light spectrum (λ < 600 nm). Interfacial electron transfer can potentially alter the degradation efficiency. The regenerated TiO(2) fiber could be reused for subsequent decolorization without a decline in adsorption efficiency compared with freshly prepared TiO(2) samples, which may be attributed to preservation of the hierarchical pore structure and restoration of the original surface properties. In summary, we propose an efficient "adsorption-photoregeneration-reuse" process applying TiO(2) fibers for the degradation of dyes in water. PMID:22544602

  14. 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.

  15. 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.

  16. Modeling PSA Problems - II: A Cell-to-Cell Transport Theory Approach

    SciTech Connect

    Labeau, P.E.; Izquierdo, J.M.

    2005-06-15

    In the first paper of this series, we presented an extension of the classical theory of dynamic reliability in which the actual occurrence of an event causing a change in the system dynamics is possibly delayed. The concept of stimulus activation, which triggers the realization of an event after a distributed time delay, was introduced. This gives a new understanding of competing events in the sequence delineation process.In the context of the level-2 probabilistic safety analysis (PSA), the information on stimulus activation mainly consists of regions of the process variables space where the activation can occur with a given probability. The evolution equations of the extended theory of probabilistic dynamics are therefore particularized to a transport process between discrete cells defined in phase-space on this basis. Doing so, an integrated and coherent approach to level-2 PSA problems is propounded. This amounts to including the stimulus concept and the associated stochastic delays discussed in the first paper in the frame of a cell-to-cell transport process.In addition, this discrete model provides a theoretical basis for the definition of appropriate numerical schemes for integrated level-2 PSA applications.

  17. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    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.

  19. 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. PMID:25201391

  20. 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. PMID:26652457

  1. 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)

  2. Assay-specific artificial neural networks for five different PSA assays and populations with PSA 2-10 ng/ml in 4,480 men.

    PubMed

    Stephan, Carsten; Xu, Chuanliang; Cammann, Henning; Graefen, Markus; Haese, Alexander; Huland, Hartwig; Semjonow, Axel; Diamandis, Eleftherios P; Remzi, Mesut; Djavan, Bob; Wildhagen, Mark F; Blijenberg, Bert G; Finne, Patrik; Stenman, Ulf-Hakan; Jung, Klaus; Meyer, Hellmuth-Alexander

    2007-03-01

    Use of percent free PSA (%fPSA) and artificial neural networks (ANNs) can eliminate unnecessary prostate biopsies. In a total of 4,480 patients from five centers with PSA concentrations in the range of 2-10 ng/ml an IMMULITE PSA-based ANN (iANN) was compared with other PSA assay-adapted ANNs (nANNs) to investigate the impact of different PSA assays. ANN data were generated with PSA, fPSA (assays from Abbott, Beckman, DPC, Roche or Wallac), age, prostate volume, and DRE status. In 15 different ROC analyses, the area under the curve (AUC) in the PSA ranges 2-4, 2-10, and 4-10 ng/ml for the nANN was always significantly larger than the AUC for %fPSA or PSA. The nANN and logistic regression models mostly also performed better than the iANN. Therefore, for each patient population, PSA assay-specific ANNs should be used to optimize the ANN outcome in order to reduce the number of unnecessary biopsies. PMID:17333205

  3. Grafting of organosilane derived from 3-glycidoxypropyltrimethoxysilane and thiourea onto magnesium phyllosilicate by sol-gel process and investigation of metal adsorption properties

    NASA Astrophysics Data System (ADS)

    Dey, R. K.; Oliveira, Andrea S.; Patnaik, Tanushree; Singh, V. K.; Tiwary, D.; Airoldi, Claudio

    2009-08-01

    A layered inorganic-organic magnesium silicate (Mg-GTPS-TU) has been successfully synthesized by using sol-gel based precursor under mild temperature conditions and a new silylaing agent (GTPS-TU) derived from 3-glycidoxypropyltrimethoxysilane (GTPS) and thiourea (TU) as the silicon source. The hybrid material was characterized through elemental analysis, infrared spectroscopy, X-ray diffractometry, thermogravimetry, and carbon and silicon solid-state nuclear magnetic resonance spectroscopy. The result confirmed the attachment of organic functionality to the inorganic silicon network. The inter-lamellar distance for the hybrid material was found to be 18.8 Å. Metal adsorption characteristics follows Cr(III) >Mn(II)>Zn(II) with more affinity towards Cr(III) in dilute aqueous solution. Evaluation of thermodynamic parameters ΔH and ΔS for Cr(III) were found to be 25.44 J mol -1 and 79.9 J mol -1 K -1, respectively, indicating adsorption process to be endothermic in nature. The negative value of Δ G indicated the feasibility and spontaneity of ongoing adsorption process at relatively higher temperature. The presence of multiple coordination sites in the attached organic functionality expresses the potentiality of the hybrid material containing new silylating agent for heavy cation removal from eco-system.

  4. Polymeric microspheres with N-methyl-D-glucamine ligands for boron removal from water solution by adsorption-membrane filtration process.

    PubMed

    Wolska, Joanna; Bryjak, Marek; Kabay, Nalan

    2010-08-01

    Polymeric microspheres with N-methyl-D-glucamine (NMDG) ligands have been tested in the adsorption-membrane filtration process for boron removal from aqueous solutions. The chelating resins were synthesized by reacting NMDG with the vinylbenzyl chloride-styrene-1,4-divinylbenzene (VBC/S/DVB) copolymer at the reflux temperature and in the microwave reactor. VBC/S/DVB spheres with a gel structure that contained 6 wt% DVB were obtained by membrane emulsification followed by suspension polymerization. By selecting the optimal emulsification and polymerization parameters, it was possible to obtain 25-microm-diameter particles with a narrow size distribution. Resins obtained by microwave modification showed the higher boron adsorption capacity. PMID:20401519

  5. Random sequential adsorption of tetramers

    NASA Astrophysics Data System (ADS)

    Cieśla, Michał

    2013-07-01

    Adsorption of a tetramer built of four identical spheres was studied numerically using the random sequential adsorption (RSA) algorithm. Tetramers were adsorbed on a two-dimensional, flat and homogeneous surface. Two different models of the adsorbate were investigated: a rhomboid and a square one; monomer centres were put on vertices of rhomboids and squares, respectively. Numerical simulations allow us to establish the maximal random coverage ratio as well as the available surface function (ASF), which is crucial for determining kinetics of the adsorption process. These results were compared with data obtained experimentally for KfrA plasmid adsorption. Additionally, the density autocorrelation function was measured.

  6. Grafting of organosilane derived from 3-glycidoxypropyltrimethoxysilane and thiourea onto magnesium phyllosilicate by sol-gel process and investigation of metal adsorption properties

    SciTech Connect

    Dey, R.K.; Oliveira, Andrea S.; Patnaik, Tanushree; Singh, V.K.; Tiwary, D.; Airoldi, Claudio

    2009-08-15

    A layered inorganic-organic magnesium silicate (Mg-GTPS-TU) has been successfully synthesized by using sol-gel based precursor under mild temperature conditions and a new silylaing agent (GTPS-TU) derived from 3-glycidoxypropyltrimethoxysilane (GTPS) and thiourea (TU) as the silicon source. The hybrid material was characterized through elemental analysis, infrared spectroscopy, X-ray diffractometry, thermogravimetry, and carbon and silicon solid-state nuclear magnetic resonance spectroscopy. The result confirmed the attachment of organic functionality to the inorganic silicon network. The inter-lamellar distance for the hybrid material was found to be 18.8 A. Metal adsorption characteristics follows Cr(III) >Mn(II)>Zn(II) with more affinity towards Cr(III) in dilute aqueous solution. Evaluation of thermodynamic parameters DELTAH and DELTAS for Cr(III) were found to be 25.44 J mol{sup -1} and 79.9 J mol{sup -1} K{sup -1}, respectively, indicating adsorption process to be endothermic in nature. The negative value of DELTAG indicated the feasibility and spontaneity of ongoing adsorption process at relatively higher temperature. The presence of multiple coordination sites in the attached organic functionality expresses the potentiality of the hybrid material containing new silylating agent for heavy cation removal from eco-system. - Abstract: We report the synthesis and adsorption properties of a layered inorganic-organic magnesium silicate (Mg-GTPS-TU) derived from a new silylaing agent from 3-glycidoxypropyltrimethoxysilane (GTPS) and thiourea (TU) as the silicon source. Display Omitted

  7. 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)

  8. Thermodynamic characterization of metal dissolution and inhibitor adsorption processes in the low carbon steel/mimosa tannin/sulfuric acid system

    NASA Astrophysics Data System (ADS)

    Martinez, Sanja; Stern, Ivica

    2002-10-01

    The corrosion rates in the presence of mimosa tannin as a low carbon steel corrosion inhibitor in sulfuric acid media, were measured by the weight loss method, in the range of temperatures from 20 to 60 °C. The Temkin, Frumkin and Freundlich isotherms were tested for their fit to the experimental data. The free energies and enthalpies for the adsorption process and the apparent activation energies, enthalpies and entropies of the dissolution process were determined. The fundamental thermodynamic functions were used to glean important information about the mimosa tannin inhibitory behavior. The results were explained in terms of chemical thermodynamics.

  9. Contribution of allelic variability in prostate specific antigen (PSA) & androgen receptor (AR) genes to serum PSA levels in men with prostate cancer

    PubMed Central

    Chavan, Sushant V.; Maitra, Anurupa; Roy, Nobhojit; Chavan, Padma R.

    2014-01-01

    Background & objectives: Wide variability in serum prostate specific antigen (PSA) levels exists in malignant conditions of the prostate. PSA is expressed in normal range in 20 to 25 per cent of prostate cancer cases even in presence of high grade Gleason score. This study was aimed to assess the influence of genetic variants exhibited by PSA and androgen receptor (AR) genes towards the variable expression of PSA in prostate cancer. Methods: Pre-treatment serum PSA levels from 101 prostate cancer cases were retrieved from medical record. PSA genotype analysis in promoter region and AR gene microsatellite Cytosine/Adenine/Guanine (CAG) repeat analysis in exon 1 region was performed using DNA sequencing and fragment analysis techniques. Results: A total of seven single nucleotide polymorphisms (SNPs) in the PSA promoter region were noted. Only two SNPs viz., 158G/A (P<0.001) in the proximal promoter region and -3845G/A (P<0.001) in enhancer region showed significant association with serum PSA levels. The carriers of homozygous GG genotype (P<0.001) at both of these polymorphic sites showed higher expression of PSA whereas homozygous AA genotype (P<0.001) carriers demonstrated lower PSA levels. The combination effect of PSA genotypes along with stratified AR CAG repeats lengths (long, intermediate and short) was also studied. The homozygous GG genotype along with AR long CAG repeats and homozygous AA genotype along with AR short CAG repeats at position -3845 and -158 showed strong interaction and thus influenced serum PSA levels. Interpretation & conclusions: The genetic variants exhibited by PSA gene at positions -3845G/A and -158G/A may be accountable towards wide variability of serum PSA levels in prostate cancer. Also the preferential binding of G and A alleles at these polymorphic sites along with AR long and short CAG repeats may contribute towards PSA expression. PMID:24820830

  10. 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.

  11. 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. PMID:27003628

  12. A Community Jury on PSA screening: what do well-informed men want the government to do about prostate cancer screening—a qualitative analysis

    PubMed Central

    Rychetnik, Lucie; Doust, Jenny; Thomas, Rae; Gardiner, Robert; MacKenzie, Geraldine; Glasziou, Paul

    2014-01-01

    Objective Cancer screening policies and programmes should take account of public values and concerns. This study sought to determine the priorities, values and concerns of men who were ‘fully informed’ about the benefits and harms of prostate-specific antigen (PSA) screening; and empirically examine the value of a community jury in eliciting public values on PSA screening. Setting Community jury was convened on the Gold Coast, Queensland (Australia) to consider PSA screening benefits and harms, and whether government campaigns on PSA screening should be conducted. Participants 27 men (volunteers) aged 50–70 with no personal history of prostate cancer and willing to attend jury 6–7 April 2013: 12 were randomly allocated to jury (11 attended). Outcome measures A qualitative analysis was conducted of the jury deliberations (audio-recorded and transcribed) to elicit the jury's views and recommendations. A survey determined the impact of the jury process on participants’ individual testing decisions compared with control group. Results The jury concluded governments should not invest in programmes focused on PSA screening directed at the public because the PSA test did not offer sufficient reassurance or benefit and could raise unnecessary alarm. It recommended an alternative programme to support general practitioners to provide patients with better quality and more consistent information about PSA screening. After the jury, participants were less likely to be tested in the future compared with the controls, but around half said they would still consider doing so. Conclusions The jury's unanimous verdict about government programmes was notable in the light of their divergent views on whether or not they would be screened themselves in the future. Community juries provide valuable insights into the priorities and concerns of men weighing up the benefits and harms of PSA screening. It will be important to assess the degree to which the findings are generalisable

  13. Ni2+-Dependent and PsaR-Mediated Regulation of the Virulence Genes pcpA, psaBCA, and prtA in Streptococcus pneumoniae

    PubMed Central

    Manzoor, Irfan; Shafeeq, Sulman; Kuipers, Oscar P.

    2015-01-01

    Previous studies have shown that the transcriptional regulator PsaR regulates the expression of the PsaR regulon consisting of genes encoding choline binding protein (PcpA), the extracellular serine protease (PrtA), and the Mn2+-uptake system (PsaBCA), in the presence of manganese (Mn2+), zinc (Zn2+), and cobalt (Co2+). In this study, we explore the Ni2+-dependent regulation of the PsaR regulon. We have demonstrated by qRT-PCR analysis, metal accumulation assays, β-galactosidase assays, and electrophoretic mobility shift assays that an elevated concentration of Ni2+ leads to strong induction of the PsaR regulon. Our ICP-MS data show that the Ni2+-dependent expression of the PsaR regulon is directly linked to high, cell-associated, concentration of Ni2+, which reduces the cell-associated concentration of Mn2+. In vitro studies with the purified PsaR protein showed that Ni2+ diminishes the Mn2+-dependent interaction of PsaR to the promoter regions of its target genes, confirming an opposite effect of Mn2+ and Ni2+ in the regulation of the PsaR regulon. Additionally, the Ni2+-dependent role of PsaR in the regulation of the PsaR regulon was studied by transcriptome analysis. PMID:26562538

  14. [Diagnosis and follow-up of prostate cancer patients using prostate specific antigen (PSA)].

    PubMed

    Kuriyama, M; Uno, H; Ueno, K; Yamamoto, N; Takahashi, Y; Shinoda, I; Ban, Y; Kawada, Y

    1997-06-01

    An international standard of prostate specific antigen (PSA) assays was constructed and prognosis of the patients with prostate cancers showing gray zone PSA was studied. For lower levels of serum PSA (< 50 ng/ml), the conversion formula to that of Tandem-R PSA from other assays was presented. Furthermore, based on the standards of Stanford Reference and Markit-MPA, conversion rates to this international standard from the conventional PSA assays were also obtained. Patients' cancer-specific survival was found to be significantly better in the gray zone group. Further studies to obtain higher specificity such as using free or complex rate in total PSA is necessary. PMID:9250498

  15. 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%. PMID:23131623

  16. Effect of Water Spray Evaporative Cooling at the Inlet of Regeneration Air Stream on the Performance of an Adsorption Desiccant Cooling Process

    NASA Astrophysics Data System (ADS)

    Ando, Kosuke; Kodama, Akio; Hirose, Tsutomu; Goto, Motonobu; Okano, Hiroshi

    This paper shows an influence of evaporative cooler at the inlet of regeneration air stream of an adsorptive desiccant cooling process on the cooling/dehumidifying performance. This evaporative cooling was expected to cause humidity increase in regeneration air reducing the dehumidifying performance of the honeycomb absorber, while the evaporative cooling plays an important role to produce a lower temperature in supply air. Two different airs to be used for the regeneration of the desiccant wheel were considered. One was fresh outside air (OA mode) and the other was air ventilated from the room (RA mode). Experimental results showed that the amount of dehumidified water obtained at the process without water spray evaporative cooler was actually larger than that of process with water spray evaporative cooler. This behavior was mainly due to increase of humidity or relative humidity in the regeneration air as expected. However, temperature of supply air produced by the process with the evaporator was rather lower than that of the other because of the cooled return air, resulting higher CE value. Regarding the operating mode, the evaporative cooler at the OA-mode was no longer useful at higher ambient humidity because of the difficulty of the evaporation of the water in such high humidity. It was also found that its dehumidifying performance was remarkably decreased at higher ambient humidity and lower regeneration temperature since the effective adsorption capacity at the resulting high relative humidity of the regeneration air decreased.

  17. Early detection, PSA screening, and management of overdiagnosis.

    PubMed

    Borza, Tudor; Konijeti, Ramdev; Kibel, Adam S

    2013-12-01

    Prostate cancer diagnosis and treatment rates have increased significantly since the introduction of prostate-specific antigen (PSA) screening. Although it was initially thought that most prostate cancers would lead to death or significant morbidity, recent randomized trials have demonstrated that many patients with screening-detected cancer will not die of their disease. Modifications to PSA screening, screening guideline statements, and novel screening markers have been developed to minimize the risk and morbidity associated with overdiagnosis and overtreatment. Less aggressive management strategies such as active surveillance may lead to lower treatment rates in men who are unlikely to benefit while maintaining cure rates. PMID:24188254

  18. Daily, monthly and seasonal variation in PSA levels and the association with weather parameters.

    PubMed

    Connolly, D; van Leeuwen, P J; Bailie, J; Black, A; Murray, L J; Keane, P F; Gavin, A

    2011-03-01

    PSA levels have shown daily and seasonal variation, although data are conflicting regarding the season with higher PSA levels and the clinical relevance of this. We assessed the correlation of total PSA levels with meteorological data on a daily, weekly, monthly and seasonal basis. Data from 53,224 men aged 45-74 years, with an initial PSA <10.0 ng ml(-1) were correlated with temperature (°C), duration of bright sunshine (hours) and rainfall (mm). There was seasonal variation in PSA levels, with median PSA being higher in spring compared with other seasons (1.18 vs 1.10 ng ml(-1), P = 0.004). Seasonal variation was not apparent when PSA levels were age-adjusted (P = 0.112). Total PSA was not correlated with daily, weekly or monthly hours of sunshine, rainfall or mean temperature. In contrast, age-adjusted PSA varied with weekday, with higher PSA levels on Thursday and Friday compared with other days (1.16 vs 1.10 ng ml(-1), respectively). On multivariate analysis, only age predicted for PSA levels >3.0 ng ml(-1). In conclusion, PSA levels did show seasonal variation, although there was no direct correlation between PSA and any meteorological parameter. The degree of seasonal variation is small and the decision to proceed to prostate biopsy should be independent of season or weather parameters. PMID:20975738

  19. Global versus local adsorption selectivity

    NASA Astrophysics Data System (ADS)

    Pauzat, Françoise; Marloie, Gael; Markovits, Alexis; Ellinger, Yves

    2015-10-01

    The origin of the enantiomeric excess found in the amino acids present in the organic matter of carbonaceous meteorites is still unclear. Selective adsorption of one of the two enantiomers existing after a racemic formation could be part of the answer. Hereafter we report a comparative study of the adsorption of the R and S enantiomers of α-alanine and lactic acid on the hydroxylated { } chiral surface of α-quartz using numerical simulation techniques. Structurally different adsorption sites were found with opposite R versus S selectivity for the same molecule-surface couple, raising the problem of whether to consider adsorption as a local property or as a global response characteristic of the whole surface. To deal with the second term of this alternative, a statistical approach was designed, based on the occurrence of each adsorption site whose energy was calculated using first principle periodic density functional theory. It was found that R-alanine and S-lactic acid are the enantiomers preferentially adsorbed, even if the adsorption process on the quartz { } surface stays with a disappointingly poor enantio-selectivity. Nevertheless, it highlighted the important point that considering adsorption as a global property changes perspectives in the search for more efficient enantio-selective supports and more generally changes the way to apprehend adsorption processes in astro-chemistry/biology.

  20. Synergetic effect between photocatalytic degradation and adsorption processes on the removal of phenolic compounds from olive mill wastewater.

    PubMed

    Baransi, Katie; Dubowski, Yael; Sabbah, Isam

    2012-03-01

    The photocatalytic degradation of two phenolic compounds, p-coumaric acid and caffeic acid, was performed with a suspended mixture of TiO(2) and powdered activated carbon (PAC) (at pH=3.4 and 8). Adsorption, direct photolysis and photocatalytic degradation were studied under different pH and UV light sources (sunlight vs. 365nm UV lamps). The potential for reusing this catalyst mixture in sequential photocatalytic runs was examined as well. Quantum yields for the direct photolysis of caffeic acid under solar and artificial 365nm light were calculated (for the first time) as 0.005 and 0.011, respectively. A higher removal rate of contaminants by either adsorption or photocatalysis was obtained at a low pH (pH 4). Furthermore, the addition of PAC increased the removal efficiency of the phenolic compounds. Fast removal of the pollutants from the solution over three sequential runs was achieved only when both TiO(2) and PAC were present. This suggests that at medium phenolic concentrations, the presence of PAC as a co-sorbent reduces surface poisoning of the TiO(2) catalyst and hence improves photocatalysis degradation of phenolic pollutants. The adsorption equilibrium of caffeic acid or p-coumaric acid on TiO(2), PAC and the combined mixture of TiO(2) and PAC follows the Langmuir isotherm model. Experiments with PAC TiO(2) mixture and olive mill wastewater (anaerobically treated and diluted by a factor of 10) showed higher removal of polyphenols than of chemical oxygen demand (COD). 87% removal of total polyphenols, compared to 58% of COD, was achieved after 24h of exposure to 365nm irradiation (7.6W/m(2)) in the presence of a suspended mixture of TiO(2) and PAC, indicating "self-selectivity" of polyphenols. PMID:22153960

  1. 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

  2. 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). PMID:24809496

  3. 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…

  4. PSA Screening Has Led to Overtreatment of Many Prostate Cancers

    Cancer.gov

    Screening for prostate cancer with the prostate-specific antigen (PSA) test has led to overtreatment of many prostate cancers, including aggressive treatments in older men considered to be at low risk for progression of the disease according to a study published in the July 26, 2010 Archives of Internal Medicine.

  5. 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. PMID:26871732

  6. Real-time dynamic adsorption processes of cytochrome c on an electrode observed through electrochemical high-speed atomic force microscopy.

    PubMed

    Takeda, Kouta; Uchihashi, Takayuki; Watanabe, Hiroki; Ishida, Takuya; Igarashi, Kiyohiko; Nakamura, Nobuhumi; Ohno, Hiroyuki

    2015-01-01

    An understanding of dynamic processes of proteins on the electrode surface could enhance the efficiency of bioelectronics development and therefore it is crucial to gain information regarding both physical adsorption of proteins onto the electrode and its electrochemical property in real-time. We combined high-speed atomic force microscopy (HS-AFM) with electrochemical device for simultaneous observation of the surface topography and electron transfer of redox proteins on an electrode. Direct electron transfer of cytochrome c (cyt c) adsorbed on a self-assembled monolayers (SAMs) formed electrode is very attractive subject in bioelectrochemistry. This paper reports a real-time visualization of cyt c adsorption processes on an 11-mercaptoundecanoic acid-modified Au electrode together with simultaneous electrochemical measurements. Adsorbing cyt c molecules were observed on a subsecond time resolution simultaneously with increasing redox currents from cyt c using EC-HS-AFM. The root mean square roughness (RRMS) from the AFM images and the number of the electrochemically active cyt c molecules adsorbed onto the electrode (Γ) simultaneously increased in positive cooperativity. Cyt c molecules were fully adsorbed on the electrode in the AFM images when the peak currents were steady. This use of electrochemical HS-AFM significantly facilitates understanding of dynamic behavior of biomolecules on the electrode interface and contributes to the further development of bioelectronics. PMID:25671430

  7. Real-Time Dynamic Adsorption Processes of Cytochrome c on an Electrode Observed through Electrochemical High-Speed Atomic Force Microscopy

    PubMed Central

    Takeda, Kouta; Uchihashi, Takayuki; Watanabe, Hiroki; Ishida, Takuya; Igarashi, Kiyohiko; Nakamura, Nobuhumi; Ohno, Hiroyuki

    2015-01-01

    An understanding of dynamic processes of proteins on the electrode surface could enhance the efficiency of bioelectronics development and therefore it is crucial to gain information regarding both physical adsorption of proteins onto the electrode and its electrochemical property in real-time. We combined high-speed atomic force microscopy (HS-AFM) with electrochemical device for simultaneous observation of the surface topography and electron transfer of redox proteins on an electrode. Direct electron transfer of cytochrome c (cyt c) adsorbed on a self-assembled monolayers (SAMs) formed electrode is very attractive subject in bioelectrochemistry. This paper reports a real-time visualization of cyt c adsorption processes on an 11-mercaptoundecanoic acid-modified Au electrode together with simultaneous electrochemical measurements. Adsorbing cyt c molecules were observed on a subsecond time resolution simultaneously with increasing redox currents from cyt c using EC-HS-AFM. The root mean square roughness (RRMS) from the AFM images and the number of the electrochemically active cyt c molecules adsorbed onto the electrode (Γ) simultaneously increased in positive cooperativity. Cyt c molecules were fully adsorbed on the electrode in the AFM images when the peak currents were steady. This use of electrochemical HS-AFM significantly facilitates understanding of dynamic behavior of biomolecules on the electrode interface and contributes to the further development of bioelectronics. PMID:25671430

  8. 28 CFR 801.3 - Processing the claim.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... TORT CLAIMS ACT PROCEDURE § 801.3 Processing the claim. (a) Will CSOSA/PSA contact you about your claim... acknowledgement indicating the filing date (that is, the date CSOSA/PSA received your claim) and the assigned claim number. Refer to the claim number in any further correspondence you may have with CSOSA/PSA on...

  9. 28 CFR 801.3 - Processing the claim.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... TORT CLAIMS ACT PROCEDURE § 801.3 Processing the claim. (a) Will CSOSA/PSA contact you about your claim... acknowledgement indicating the filing date (that is, the date CSOSA/PSA received your claim) and the assigned claim number. Refer to the claim number in any further correspondence you may have with CSOSA/PSA on...

  10. 28 CFR 801.3 - Processing the claim.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... TORT CLAIMS ACT PROCEDURE § 801.3 Processing the claim. (a) Will CSOSA/PSA contact you about your claim... acknowledgement indicating the filing date (that is, the date CSOSA/PSA received your claim) and the assigned claim number. Refer to the claim number in any further correspondence you may have with CSOSA/PSA on...

  11. 28 CFR 801.3 - Processing the claim.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... TORT CLAIMS ACT PROCEDURE § 801.3 Processing the claim. (a) Will CSOSA/PSA contact you about your claim... acknowledgement indicating the filing date (that is, the date CSOSA/PSA received your claim) and the assigned claim number. Refer to the claim number in any further correspondence you may have with CSOSA/PSA on...

  12. 28 CFR 801.3 - Processing the claim.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... TORT CLAIMS ACT PROCEDURE § 801.3 Processing the claim. (a) Will CSOSA/PSA contact you about your claim... acknowledgement indicating the filing date (that is, the date CSOSA/PSA received your claim) and the assigned claim number. Refer to the claim number in any further correspondence you may have with CSOSA/PSA on...

  13. Fibronectin adsorption on surface-modified polyetherurethanes and their differentiated effect on specific blood elements related to inflammatory and clotting processes.

    PubMed

    Hugoni, Ludivine; Montaño-Machado, Vanessa; Yang, Meilin; Pauthe, Emmanuel; Mantovani, Diego; Santerre, J Paul

    2016-01-01

    After the introduction of a medical device into the body, adhesive proteins such as fibronectin (Fn) will adsorb to the surface of the biomaterial. Monocytes (MCs) will interact with these adsorbed proteins, and adopt either a proinflammatory and/or prowound healing phenotype, thereby influencing many blood interaction events including thrombogenesis. In this work, Fn adsorption as well as subsequent MC response and thrombus formation were investigated on two surfaces-modified polyetherurethanes (PEUs) using different surface modifiers: an anionic/dihydroxyl oligomeric (ADO) additive, known to enable cell adhesion, and a fluorinated polypropylene oxide oligomer (PPO), known to reduce platelet adhesion. Results indicated that at 24 h of MC culture, PEU-ADO and PEU-PPO promoted an anti-inflammatory character relative to the base PEU. Longer clotting times, based on a free hemoglobin assay, were also found on the two surface-modified PEUs relative to the native one, suggesting their potential for the reduction of thrombus formation. In presence of a Fn monolayer, the surface-modified PEUs conserved a lower thrombogenic character than the base PEU, and was however significantly decreased when compared to prior protein adsorption. Furthermore, Fn coatings increased the MC production levels of tumor necrosis factor-α and interleukin-10 at 24 h, while not affecting the anti-inflammatory effect of the modifications relative to the base PEU. This finding was most prominent on PEU-PPO, suggesting that the interaction of the adsorbed Fn with blood cells was different for the two additives. Hence, the results highlighted differentiating effects of Fn adsorption on specific blood activating processes related to inflammatory and thrombotic responses. PMID:27246517

  14. 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

  15. Adsorption of Co(II), Ni(II), Cu(II), and Zn(II) on hexagonal templated zirconia obtained thorough a sol-gel process: the effects of nanostructure on adsorption features.

    PubMed

    de Farias, Robson F; do Nascimento, Ana A S; Bezerra, Cícero W B

    2004-09-01

    Using zirconium tetrabutoxide, diaminedecane, and diamineoctane as precursors, a templated hexagonal zirconia matrix is synthesized and characterized by X-ray diffractometry and scanning electron microscopy. The adsorption capacity of such a matrix toward Co(II), Ni(II), Cu(II), and Zn(II) from aqueous solutions is studied. The adsorption affinity of the synthesized hexagonal templated zirconia toward the cations is Cu(II)>Zn(II) >Ni(II)>Co(II). It is also verified that the adsorption of the cations follows a Langmuir and not a Freundlich isotherm. All obtained isotherms are of type I, according to the IUPAC classification. The observed adsorption affinity sequence can be explained by taking into account the velocity constant for the substitution of water molecules into the cation coordination spheres, as well as the Irving-Williams series. PMID:15276032

  16. Chromatogram Handler: A unique computer program that efficiently processes data generated in liquid chromatographic investigations of organic ligand adsorption on mineral surfaces

    NASA Astrophysics Data System (ADS)

    Kreller, David I.; Young, Stephen P.; Mendez, Eladio A.; McGunigale, Samantha L.

    2012-09-01

    We describe a unique C# computer program developed in our laboratory to efficiently manipulate data generated when a novel liquid chromatographic (LC) 'pulsed addition' technique is used to study organic ligand interactions with mineral surfaces. We are not aware of the existence of a program of this nature elsewhere. Geochemically-relevant ligands studied include dissolved organic matter (DOM) mixtures and single component low molecular weight organic acids. Although our LC system has three optical (absorbance and fluorescence) detection channels, the utility can process data from experiments in which data was collected in one, two or three detection channels. If not automated, data management and processing for the technique is prohibitively complex and time-consuming, due large data volumes and the number of operations involved. The input for the utility in a processing run is the set of detector output files generated during an LC experiment. During processing, the utility generates an MS Excel output file within which, for each detection channel: (i) chromatographic peak areas and peak retention times are determined, (ii) area-normalized per-injection and cumulative adsorption densities are calculated, and (iii) graphical representations of various quantities calculated from the raw data are automatically generated. When processing data from experiments with multiple detection channels, the utility additionally prepares graphs that compare recovery values calculated from data in different detection channels, and calculates (and plots) spectroscopic/chromatographic indices which are ratios of signals in various detection channels. The utility was programmed to perform these additional operations on data from multi-channel experiments because (i) 'Interchannel' comparisons of recovery provide insight into the differing surface behavior of distinct DOM sub-fractions, and (ii) the spectroscopic indices provide a useful new form of data that provides insight into

  17. Random sequential adsorption on fractals

    NASA Astrophysics Data System (ADS)

    Ciesla, Michal; Barbasz, Jakub

    2012-07-01

    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.

  18. 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. PMID:22852643

  19. 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...

  20. 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. PMID:17659833

  1. Efficient conversion of dimethylarsinate into arsenic and its simultaneous adsorption removal over FeCx/N-doped carbon fiber composite in an electro-Fenton process.

    PubMed

    Lan, Huachun; Li, Jianfei; Sun, Meng; An, Xiaoqiang; Hu, Chengzhi; Liu, Ruiping; Liu, Huijuan; Qu, Jiuhui

    2016-09-01

    In this study, a FeCx/N-doped carbon fiber composite (FeCx/NCNFs) was developed via an electrospinning method. According to the characterization results of XRD, TEM and XPS, FeCx (a mixture of Fe7C3 and Fe3C) was either embedded in or attached to the NCNFs. It was used for the first time as a catalyst for dimethylarsinate (DMA) degradation and as an absorbent for inorganic arsenic (As (V)), with degradation and adsorption occurring simultaneously, in an electro-Fenton process. The effects of catalyst dosage, initial DMA concentration, solution pH, and applied current on the treatment efficiency and the corresponding H2O2 generation were systematically investigated. The results showed that DMA could be efficiently oxidized into As(V). 96% of DMA was degraded after reaction time of 360 min and the residual As(V) concentration in solution was below the allowable limit of 0.01 mg/L under the optimum treatment conditions. Based on an ESR and radical scavenger experiment, OH was proven to be the sole reactive oxygen species involved in the degradation process of DMA. DMA was oxidized to MMA as the primary oxidation product, which was subsequently oxidized to inorganic arsenic, As (V). TOC was also efficiently removed at the same time. The DMA removal mechanism for simultaneous degradation of dimethylarsinate and adsorption of arsenic over FeCx/NCNFs in the electro-Fenton process was also proposed based on the experimental results. PMID:27179339

  2. Level 2 PSA insights relative to filtered vent system

    SciTech Connect

    Deremer, R.K.; Fleming, K.N.; Landolt, J.

    1996-07-01

    A full-scope Level 2 probabilistic safety analysis (PSA) of the Goesgen Nuclear Power Plant was completed early in 1994. During the PSA, a containment filtered vent system was installed at the plant to meet requirements of the Swiss safety authorities. The purpose of the vent system is to provide a mechanism to depressurize the containment atmosphere in a controlled manner during the late phase of a severe accident in order to preclude gradual over pressurization of the containment and filter any release of radioactive materials to the environment. To ensure a high degree of reliability, it was required to include a design feature to open the vent passively via the use of a rupture disc whose opening is highly reliable and independent of operator actions. The PSA addressed two issues associated with the vent system: (1) What is the optimum pressure to select for the rupture disc setpoint? and (2) What is the best strategy for the use of the rupture disc isolation valves (i.e., should they be left open normally to ensure the opening of the vent at the rupture disc setpoint or should they be left closed and opened by the operator only during a severe accident)? Based on the results generated by the PSA, which indicated that the downside risk of inadvertent opening in the early phase of an accident was greater than the upside benefit of a passively actuated vent in the late phase of an accident, it was concluded that it is prudent to have the rupture disc normally isolated from the containment.

  3. 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. PMID:24871934

  4. Facile synthesis of alumina hollow microspheres via trisodium citrate-mediated hydrothermal process and their adsorption performances for p-nitrophenol from aqueous solutions.

    PubMed

    Zhou, Jiabin; Wang, Lei; Zhang, Zhong; Yu, Jiaguo

    2013-03-15

    Alumina hollow microspheres with high adsorption affinity toward p-nitrophenol in water were prepared by using urea and trisodium citrate as precipitating and mediating agents, respectively, via a simple one-pot hydrothermal synthesis followed by calcination. The as-prepared samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and nitrogen adsorption-desorption isotherms measurement. This study shows that the morphology, specific surface area, and the pore structure of the resulting materials can be controlled by varying the concentration of trisodium citrate. The result of adsorption of p-nitrophenol onto the as-prepared samples revealed that the pseudo-second-order kinetic equation can better describe the adsorption kinetics. Furthermore, adsorption isotherm studies indicated that the resulting alumina microspheres are powerful adsorbents for the removal of p-nitrophenol from water with maximum adsorption capacity of 217.4 mg/g. PMID:23276687

  5. 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.

  6. 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...

  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. 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

  9. Adsorption of octylamine on titanium dioxide

    NASA Astrophysics Data System (ADS)

    Siwińska, Daria; Kołodziejczak-Radzimska, Agnieszka; Krysztafkiewicz, Andrzej; Jesionowski, Teofil

    2009-05-01

    Processes of adsorption and desorption of a model active substance (octylamine) on the surface of unmodified titanium dioxide (E 171) have been performed. The effects of concentration of octylamine and time of the process on the character of adsorption have been studied and the efficiency of the adsorption/desorption has been determined. The samples obtained have been studied by X-ray diffraction. The nitrogen adsorption/desorption isotherms, particle size distribution and absorption capacities of water, dibutyl phthalate and paraffin oil have been determined. The efficiency of octylamine adsorption on the surface of the titanium dioxide has been found positively correlated with the concentration of octylamine in the initial solution. The desorption of octylamine has decreased with increasing concentration of this compound adsorbed. For octylamine in low concentrations the physical adsorption has been found to dominate, which is desirable when using TiO 2 in the production of pharmaceuticals.

  10. 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. PMID:25770957

  11. 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)

  12. [Clinical evaluation of tandem PSA for the diagnosis and follow-up of prostate cancer].

    PubMed

    Okaneya, T; Mizusawa, H; Taguchi, I; Yoneyama, T

    1996-11-01

    The Tandem PSA test was performed simultaneously with assay of Markit-M PA and gamma-seminoprotein to determine its usefulness for the diagnosis of prostate cancer in a total of 81 patients with prostate diseases. The diagnosis was untreated prostate cancer in 16 patients including 2 with T1c tumor, benign prostatic hyperplasia in 56 patients, and other diseases in 9 patients. Tandem PSA, Markit-M PA, and gamma-seminoprotein showed a sensitivity of 81.3, 62.5, and 68.8%, respectively, while the specificity was 67.7, 81.5, and 72.3%, respectively. Tandem PSA had the highest sensitivity, although the specificity and accuracy were the lowest. These results were considered to be due to the fact that the PSA level becomes significantly higher with an increase in the weight of benign prostatic hyperplasia. This indicates that the PSA density should be considered to improve the specificity of Tandem PSA. Use of the Tandem PSA/gamma-seminoprotein ratio was also examined as a possible method which might improve the specificity. Patients with benign prostatic hyperplasia and prostate cancer had a ratio of 1.53 +/- 0.966 and 3.21 +/- 1.811 (mean plus standard deviation), respectively, and these 2 groups showed a significant difference (p = 0.0008). This indicates that calculation of the Tandem PSA/gamma-seminoprotein ratio may be useful to improve the specificity of Tandem PSA for the diagnosis of prostate cancer. PMID:8973936

  13. Losing the Dark: A Planetarium PSA about Light Pollution

    NASA Astrophysics Data System (ADS)

    Petersen, Carolyn Collins; Walker, Constance

    2015-03-01

    Losing the Dark is a six-minute PSA video created for fulldome theaters by Loch Ness Productions, the International Dark Sky Association Education Committee headed by Dr. Constance Walker of the National Optical Astronomy Observatories, Dome3, Adler Planetarium, and Babak Tafreshi (The World at Night). It explains light pollution, its effects, and ways to implement ``wise lighting`` practices to mitigate light pollution. The show is also made in flat-screen HD format for classical planetariums, non-dome theaters, and for presentatons by IDA speakers.

  14. Hollow-fiber-based adsorbers for gas separation by pressure-swing adsorption

    SciTech Connect

    Feng, X.; Pan, C.Y.; McMinis, C.W.; Ivory, J.; Ghosh, D.

    1998-07-01

    Hollow-fiber-based adsorbers for gas separation by pressure-swing adsorption (PSA) was studied experimentally. The high efficiency of hollow-fiber-based adsorbers for gas separation was illustrated by hydrogen separation using fine-powder-activated carbon and molecular sieve as adsorbents. The adsorption equilibrium and dynamics of the hollow-fiber adsorbers were determined. The pressure drop of the gas flowing through the adsorbers was also examined. The adsorbers were tested for hydrogen separation from nitrogen, carbon dioxide, and a multicomponent gas mixture simulating ammonia synthesis purge gas. The PSA systems using the hollow-fiber adsorbers were very effective for hydrogen purification. The high separation efficiency is derived from the fast mass-transfer rate and low pressure drop, two key features of hollow-fiber-based adsorbers.

  15. 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

  16. Coupling of ultrasound-assisted extraction and expanded bed adsorption for simplified medicinal plant processing and its theoretical model: extraction and enrichment of ginsenosides from Radix Ginseng as a case study.

    PubMed

    Mi, Jianing; Zhang, Min; Zhang, Hongyang; Wang, Yuerong; Wu, Shikun; Hu, Ping

    2013-02-01

    A high-efficient and environmental-friendly method for the preparation of ginsenosides from Radix Ginseng using the method of coupling of ultrasound-assisted extraction with expanded bed adsorption is described. Based on the optimal extraction conditions screened by surface response methodology, ginsenosides were extracted and adsorbed, then eluted by the two-step elution protocol. The comparison results between the coupling of ultrasound-assisted extraction with expanded bed adsorption method and conventional method showed that the former was better than the latter in both process efficiency and greenness. The process efficiency and energy efficiency of the coupling of ultrasound-assisted extraction with expanded bed adsorption method rapidly increased by 1.4-fold and 18.5-fold of the conventional method, while the environmental cost and CO(2) emission of the conventional method were 12.9-fold and 17.0-fold of the new method. Furthermore, the theoretical model for the extraction of targets was derived. The results revealed that the theoretical model suitably described the process of preparing ginsenosides by the coupling of ultrasound-assisted extraction with expanded bed adsorption system. PMID:23341270

  17. 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.

  18. Host receptors for bacteriophage adsorption.

    PubMed

    Bertozzi Silva, Juliano; Storms, Zachary; Sauvageau, Dominic

    2016-02-01

    The adsorption of bacteriophages (phages) onto host cells is, in all but a few rare cases, a sine qua non condition for the onset of the infection process. Understanding the mechanisms involved and the factors affecting it is, thus, crucial for the investigation of host-phage interactions. This review provides a survey of the phage host receptors involved in recognition and adsorption and their interactions during attachment. Comprehension of the whole infection process, starting with the adsorption step, can enable and accelerate our understanding of phage ecology and the development of phage-based technologies. To assist in this effort, we have established an open-access resource--the Phage Receptor Database (PhReD)--to serve as a repository for information on known and newly identified phage receptors. PMID:26755501

  19. PSA nadir predicts biochemical and distant failures after external beam radiotherapy for prostate cancer: A multi-institutional analysis

    SciTech Connect

    Ray, Michael E. . E-mail: mray@umich.edu; Thames, Howard D.; Levy, Larry B.; Horwitz, Eric M.; Kupelian, Patrick A.; Martinez, Alvaro A.; Michalski, Jeff M.; Pisansky, Thomas M.; Shipley, William U.; Zelefsky, Michael J.; Zietman, Anthony L.; Kuban, Deborah A.

    2006-03-15

    Purpose: To determine the significance of prostate-specific antigen (PSA) nadir (nPSA) and the time to nPSA (T{sub nPSA}) in predicting biochemical or clinical disease-free survival (PSA-DFS) and distant metastasis-free survival (DMFS) in patients treated with definitive external beam radiotherapy (RT) for clinical Stage T1b-T2 prostate cancer. Methods and Materials: Nine participating institutions submitted data on 4839 patients treated between 1986 and 1995 for Stage T1b-T2cN0-NxM0 prostate cancer. All patients were treated definitively with RT alone to doses {>=}60 Gy, without neoadjuvant or planned adjuvant androgen suppression. A total of 4833 patients with a median follow-up of 6.3 years met the criteria for analysis. Two endpoints were considered: (1) PSA-DFS, defined as freedom from PSA failure (American Society for Therapeutic Radiology and Oncology definition), initiation of androgen suppression after completion of RT, or documented local or distant failure; and (2) DMFS, defined as freedom from clinically apparent distant failure. In patients with failure, nPSA was defined as the lowest PSA measurement before any failure. In patients without failure, nPSA was the lowest PSA measurement during the entire follow-up period. T{sub nPSA} was calculated from the completion of RT to the nPSA date. Results: A greater nPSA level and shorter T{sub nPSA} were associated with decreased PSA-DFS and DMFS in all patients and in all risk categories (low [Stage T1b, T1c, or T2a, Gleason score {<=}6, and PSA level {<=}10 ng/mL], intermediate [Stage T1b, T1c, or T2a, Gleason score {<=}6, and PSA level >10 but {<=}20 ng/mL, or Stage T2b or T2c, Gleason score {<=}6, and PSA level {<=}20 ng/mL, or Gleason score 7 and PSA level {<=}20 ng/mL], and high [Gleason score 8-10 or PSA level >20 ng/mL]), regardless of RT dose. The 8-year PSA-DFS and DMFS rate for patients with nPSA <0.5 ng/mL was 75% and 97%; nPSA {>=}0.5 but <1.0 ng/mL, 52% and 96%; nPSA {>=}1.0 but <2.0 ng/mL, 40

  20. PSA results for Hanford high level waste Tank 101-SY

    SciTech Connect

    MacFarlane, D.R.; Bott, T.F.; Brown, L.F.; Stack, D.W.; Kindinger, J.; Deremer, R.K.; Medhekar, S.R.; Mikschl, T.J.

    1993-10-01

    Los Alamos National Laboratory has performed a comprehensive probabilistic safety assessment (PSA) that includes consideration of external events for the weapons-production wastes stored in tank number 241-SY-101, commonly known as Tank 101-SY, as configured in December 1992. This tank, which periodically releases (``burps``) a gaseous mixture of hydrogen, nitrous oxide, ammonia, and nitrogen, was analyzed because of public safety concerns associated with the potential for release of radioactive tank contents should this gas mixture be ignited during one of the burps. In an effort to mitigate the burping phenomenon, an experiment is underway in which a large pump has been inserted into the tank to determine if pump-induced circulation of the tank contents will promote a slow, controlled release of the gases. This PSA for Tank 101-SY, which did not consider the pump experiment or future tank-remediation activities, involved three distinct tasks. First, the accident sequence analysis identified and quantified those potential accidents whose consequences result in tank material release. Second, characteristics and release paths for the airborne and liquid radioactive source terms were determined. Finally, the consequences, primarily onsite and offsite potential health effects resulting from radionuclide release, were estimated, and overall risk curves were constructed. An overview of each of these tasks and a summary of the overall results of the analysis are presented in the following sections.

  1. Modeling Characteristics of an Operational Probabilistic Safety Assessment (PSA)

    SciTech Connect

    Anoba, Richard C.; Khalil, Yehia; Fluehr, J.J. III; Kellogg, Richard; Hackerott, Alan

    2002-07-01

    Probabilistic Safety Assessments (PSAs) are increasingly being used as a tool for supporting the acceptability of design, procurement, construction, operation, and maintenance activities at nuclear power plants. Since the issuance of Generic Letter 88-20 and subsequent Individual Plant Examinations (IPEs)/Individual Plant Examinations for External Events (IPEEEs), the NRC has issued several Regulatory Guides such as RG 1.182 to describe the use of PSA in risk informed regulation activities. The PSA models developed for the IPEs were typically based on a 'snapshot' of the the risk profile at the nuclear power plant. The IPE models contain implicit assumptions and simplifications that limit the ability to realistically assess current issues. For example, IPE modeling assumptions related to plant configuration limit the ability to perform online equipment out-of-service assessments. The lack of model symmetry results in skewed risk results. IPE model simplifications related to initiating events have resulted in non-conservative estimates of risk impacts when equipment is removed from service. The IPE models also do not explicitly address all external events that are potentially risk significant as equipment is removed from service. (authors)

  2. Active surveillance in patients with a PSA >10 ng/mL

    PubMed Central

    Toren, Paul; Wong, Lih-Ming; Timilshina, Narhari; Alibhai, Shabbir; Trachtenberg, John; Fleshner, Neil; Finelli, Antonio

    2014-01-01

    Introduction: The use of prostate-specific antigen (PSA) in active surveillance (AS) for prostate cancer is controversial. Some consider it an unreliable marker and others as sufficient evidence to exclude patients from AS. We analyzed our cohort of AS patients with a PSA over 10 ng/mL. Methods: We included patients who had clinical T1c–T2a Gleason ≤6 disease, and ≤3 positive cores with ≤50% core involvement at diagnostic biopsy and ≥2 total biopsies. Patients were divided into 3 groups: (1) those with baseline PSA >10 ng/mL, (2) those with a PSA rise >10 ng/mL during follow-up; and (3) those with a PSA <10 ng/mL throughout AS. Adverse histology was defined as biopsy parameters exceeding the entry criteria limits. We further compared this cohort to a concurrent institutional cohort with equal biopsy parameters treated with immediate radical prostatectomy. Results: Our cohort included 698 patients with a median follow-up of 46.2 months. In total, 82 patients had a baseline PSA >10 ng/mL and 157 had a PSA rise >10 ng/mL during surveillance. No difference in adverse histology incidence was detected between groups (p = 0.3). Patients with a PSA greater than 10 were older and had higher prostate volumes. Hazard ratios for groups with a PSA >10 were protective against adverse histology. Larger prostate volume and minimal core involvement appear as factors related to this successful selection of patients to be treated with AS. Conclusion: These results suggest that a strict cut-off PSA value for all AS patients is unwarranted and may result in overtreatment. Though lacking long-term data and validation, AS appears safe in select patients with a PSA >10 ng/mL and low volume Gleason 6 disease. PMID:25408810

  3. PSA Decrease During Combined-Modality Radiotherapy Predicts for Treatment Outcome

    SciTech Connect

    Kubicek, Gregory J.; Naguib, Marco; Redfield, Sandy; Grayback, Nola; Olszanski, Arthur; Dawson, George; Brown, Sam I.

    2010-11-01

    Purpose: Prostate-specific antigen (PSA) is the well-used marker in the diagnosis, prognosis, and follow-up for prostate cancer patients. Although reports have focused on the importance of pretreatment PSA levels, doubling time, and posttreatment nadirs, there is little information on the value of PSA during the course of radiotherapy. Methods and Materials: Retrospective review of PSA values obtained midway through a course of radiotherapy treatment for prostate cancer. Patients had a PSA (midPSA) measured after a course of external beam radiation (EBRT) before planned transperineal low-dose-rate brachytherapy implant (LDR). Results: A total of 717 patients were analyzed with a median follow-up of 5.8 years, all censored patients had a minimum follow-up of 2 years. A total of 277 patients had low-risk disease, 267 patients had intermediate risk, and 173 patients had high-risk disease. Androgen blockade was used in 512 patients. A total of 653 patients had a midPSA decrease after EBRT, the median decrease was 6.2 ng/mL. Patients who had a midPSA decrease {>=}25% compared with pretreatment PSA had improved overall survival of 10.0 vs. 7.4 years (p < 0.0004) and improved disease-free survival of 9.8 vs. 7.3 years (p < 0.01). When stratified by use of androgen blockade, midPSA remained significant for both androgen and non-androgen patients. Conclusions: PSA response after EBRT before brachytherapy predicts for long-term outcome; this may allow for risk stratification and intervention with higher LDR doses to improve outcomes.

  4. Immune impact induced by PROSTVAC (PSA-TRICOM), a therapeutic vaccine for prostate cancer.

    PubMed

    Gulley, James L; Madan, Ravi A; Tsang, Kwong Y; Jochems, Caroline; Marté, Jennifer L; Farsaci, Benedetto; Tucker, Jo A; Hodge, James W; Liewehr, David J; Steinberg, Seth M; Heery, Christopher R; Schlom, Jeffrey

    2014-02-01

    PSA-TRICOM (PROSTVAC) is a novel vector-based vaccine designed to generate a robust immune response against prostate-specific antigen (PSA)-expressing tumor cells. The purpose of this report is to present an overview of both published studies and new data in the evaluation of immune responses to the PSA-TRICOM vaccine platform, currently in phase III testing. Of 104 patients tested for T-cell responses, 57% (59/104) demonstrated a ≥ 2-fold increase in PSA-specific T cells 4 weeks after vaccine (median 5-fold increase) compared with pre-vaccine, and 68% (19/28) of patients tested mounted post-vaccine immune responses to tumor-associated antigens not present in the vaccine (antigen spreading). The PSA-specific immune responses observed 28 days after vaccine (i.e., likely memory cells) are quantitatively similar to the levels of circulating T cells specific for influenza seen in the same patients. Measurements of systemic immune response to PSA may underestimate the true therapeutic immune response (as this does not account for cells that have trafficked to the tumor) and does not include antigen spreading. Furthermore, although the entire PSA gene is the vaccine, only one epitope of PSA is evaluated in the T-cell responses. Because this therapeutic vaccine is directed at generating a cellular/Th1 immune response (T-cell costimulatory molecules and use of a viral vector), it is not surprising that less than 0.6% of patients (2/349) tested have evidence of PSA antibody induction following vaccine. This suggests that post-vaccine PSA kinetics were not affected by PSA antibodies. An ongoing phase III study will evaluate the systemic immune responses and correlation with clinical outcomes. PMID:24778277

  5. [Value of serum PSA and PAP measurement with newly developed latex turbidimetric immunoassay].

    PubMed

    Akino, H; Tsuka, H; Okada, K; Tsuchiya, Y; Matsubara, M; Arimura, K

    1995-06-01

    Serum prostate specific antigen (PSA) and prostatic acid-phosphatase (PAP) levels in normal controls, and patients with prostate cancer, benign prostate hypertrophy (BPH) and other urological diseases were examined with a newly developed latex turbidimetric immunoassay (LPIA ACE PSA, LPIA ACE PAP, IATRON LABORATORIES, INC., Tokyo, Japan). The advantageous characteristics of this method are small amount (10 microliters) of serum required and short time (about 20 min.) for performing this assay. There was a high linear correlation between LPIA ACE PSA and MARKIT-F PA (r2 = 0.953), between LPIA ACE PSA and TANDEM-E PSA (r2 = 0.881) and between LPIA ACE PAP and ABBOTT-PAP EIA (r2 = 0.946). When the BPH patients (n = 110) were used as negative controls, the cut-off value of PSA was determined to be 4.3 ng/ml. Using this level as the cut-off value, the sensitivity was 78% (42 positive/54 untreated prostate cancer patients), specificity (negative rate in BPH patients) was 95% and efficiency was 89%. In a follow-up study of prostate cancer, the PSA value was elevated above the cut-off value in 68% at the time of clinical progression. These findings suggest that LPIA ACE PSA is a useful tool for serum PSA measurement. The cut-off value of PAP measured with LPIA ACE PAP was 9.0 ng/ml, which was determined by the same method as PSA. The sensitivity, specificity and efficiency ware 39%, 96% and 77%, respectively. These findings indicate that PAP is less useful than PSA in the diagnosis of prostate cancer.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7544063

  6. Development of facile property calculation model for adsorption chillers based on equilibrium adsorption cycle

    NASA Astrophysics Data System (ADS)

    Yano, Masato; Hirose, Kenji; Yoshikawa, Minoru; Thermal management technology Team

    Facile property calculation model for adsorption chillers was developed based on equilibrium adsorption cycles. Adsorption chillers are one of promising systems that can use heat energy efficiently because adsorption chillers can generate cooling energy using relatively low temperature heat energy. Properties of adsorption chillers are determined by heat source temperatures, adsorption/desorption properties of adsorbent, and kinetics such as heat transfer rate and adsorption/desorption rate etc. In our model, dependence of adsorption chiller properties on heat source temperatures was represented using approximated equilibrium adsorption cycles instead of solving conventional time-dependent differential equations for temperature changes. In addition to equilibrium cycle calculations, we calculated time constants for temperature changes as functions of heat source temperatures, which represent differences between equilibrium cycles and real cycles that stemmed from kinetic adsorption processes. We found that the present approximated equilibrium model could calculate properties of adsorption chillers (driving energies, cooling energies, and COP etc.) under various driving conditions quickly and accurately within average errors of 6% compared to experimental data.

  7. Effective Operation for an Adsorptive Desiccant Cooling Process using a Double-Stage Regeneration of Honeycomb Rotary Dehumidifier

    NASA Astrophysics Data System (ADS)

    Kodama, Akio; Ando, Kouke; Hirose, Tsutomu; Goto, Motonobu; Tuziguchi, Takuya; Okano, Hiroshi

    A double-stage regeneration concept has been applied to a rotary dehumidifier to achieve a high efficient desiccant cooling process. In this concept, regeneration zone of the dehumidifier was divided into two zones. One was pre-regeneration zone where the desiccant rotor was regenerated by warm air heated at the sensible heat exchanger, and the other was heating regeneration zone where the rotor was further regenerated by hot air heated up to the controlled temperature at a heating system. In this paper, the influence of the area ratio of these two zones on the dehumidifying/cooling performance and energy efficiency of this desiccant system were mainly discussed at several levels of the regeneration temperature, supply air velocity and inlet air humidity. Experimental results indicated that the area ratio of the heating regeneration zone should be optimized to produce a sufficient dehumidifying/cooling performance with high energy efficiency, considering humidity requested in supply air. It was also found that the amount of energy input was rather decreased than the decrease of the cooling performance as the area ratio of the heating regeneration zone decreased, and this tendency was more remarkable at higher regeneration temperature. Finally, the double-stage regeneration was confirmed to be an effective operating method for the desiccant cooling process equipped with a otary dehumidifier.

  8. 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.

  9. Van Der Waals-Corrected Density Functional Theory Simulation of Adsorption Processes on Noble-Metal Surfaces: Xe on Ag(111), Au(111), and Cu(111)

    NASA Astrophysics Data System (ADS)

    Silvestrelli, Pier Luigi; Ambrosetti, Alberto

    2016-02-01

    The DFT/vdW-WF2s1 method based on the generation of localized Wannier functions, recently developed to include the van der Waals interactions in the density functional theory and describe adsorption processes on metal surfaces by taking metal-screening effects into account, is applied to the case of the interaction of Xe with noble-metal surfaces, namely Ag(111), Au(111), and Cu(111). The study is also repeated by adopting the DFT/vdW-QHO-WF variant relying on the quantum harmonic oscillator model which describes well many body effects. Comparison of the computed equilibrium binding energies and distances, and the C_3 coefficients characterizing the adatom-surface van der Waals interactions, with available experimental and theoretical reference data shows that the methods perform well and elucidates the importance of properly including screening effects. The results are also compared with those obtained by other vdW-corrected DFT schemes, including PBE-D, vdW-DF, vdW-DF2, rVV10, and by the simpler local density approximation and semi-local (PBE) generalized gradient approximation approaches.

  10. 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. PMID:21752419

  11. Effects of adsorption and roughness upon the collision processes at the convertor surface of a plasma sputter negative ion source.

    PubMed

    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. PMID:22380231

  12. 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.

  13. Adsorptive/photo-catalytic process for naphthalene removal from aqueous media using in-situ nickel doped titanium nanocomposite.

    PubMed

    Sharma, Ajit; Lee, Byeong-Kyu

    2015-05-15

    The present study investigates the synthesis and characterization of in-situ nickel doped titanium nanocomposite (TiO2/NiO) use as an adsorbent and a photo-catalyst for naphthalene removal from aqueous phase. Nickel-titanium nanocomposites were synthesized by using an in-situ process for the nickel doping and further calcined at 600 °C for 6 h to produce the desired TiO2/NiO nanocomposite, which was then characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and UV-Vis analysis before and after naphthalene removal. The removal of naphthalene was explored with effect of pH, time and initial concentration of naphthalene (2-25 mg/L) in the presence of dark and light phases. Naphthalene removal tests were conducted under both batch and continuous flow conditions. A special column without any channeling problem was successfully designed for the removal of naphthalene by continuous flow process in the presence of visible light source. The removal was maximized at pH 6.5. The maximum amount of naphthalene removed by TiO2/NiO(0.1) nanocomposite in the presence of visible light phase was 322.1 mg/g, which was 2.5 times greater than that of the parent TiO2. The removal of naphthalene obtained during the breakthrough analysis was consistent with the batch equilibrium data. PMID:25819351

  14. Improvement of amine-modification with piperazine for the adsorption of CO2

    NASA Astrophysics Data System (ADS)

    Xue, Quanmin; Wu, Di; Zhou, Yaping; Zhou, Li

    2012-02-01

    Both selectivity and capacity of CO2 adsorption were considerably increased when PZ (piperazine) was added in MDEA (methyldiethylamine) that used to modify the surface of silica gels. The adsorbent saturated with CO2 was regenerated at ambient temperature through nitrogen purge. A set of PSA (pressure swing adsorption) operation with 200 cycles was carried out and applicability of the modified adsorbent was thus illustrated. The CO2 content in the column-top stream decreased from 13% to below 0.05% at steady state.

  15. [Adsorption and Desorption Characteristics of Endosulfan in Purple Soil].

    PubMed

    Zhao, Yan; Zheng, Guo-can; Zhu, Heng; Zhang, Jin-zhong; Zhu, Xiu-ying; Hu, Shu-chun; Wu, Ya-lin

    2015-09-01

    In order to reveal the residual process of endosulfan in purple soil and protect soil ecological environment, the adsorption and desorption characteristics of endosulfan in purple soil were investigated, and effects of temperature, adsorbent amount, and initial pH of adsorption solution on the adsorption capacity were also examined by static adsorption and desorption experiments. The results showed that the adsorption kinetic process could be well described by the second-order kinetic equation with the initial rate constants of α-, β-endosulfan as 0. 157 and 0. 115 mg.(g.min)-1, respectively. The adsorption thermodynamic process could be well described by the Langmuir isotherm with the maximum adsorption capacities of α-, β-endosulfan as 0. 257 mg . g -1 and 0. 155 mg . g -1, respectively. The adsorption process of endosulfan in purple soil may be an exothermic physicochemical process, and is dominated by physical adsorption. Under the experimental conditions examined in this study, the initial pH of adsorption solution had a relative great influence on the adsorption capacity, whereas the temperature and adsorbent amount had no significant influence. The desorption experiments found that the maximum desorption capacities of α-, β-endosulfan adsorbed in purple soil were 0. 029 mg . g -1 and 0. 017 mg . g -1 at 6 and 4 h, and accounted for 10. 5% and 16. 1% in the maximum adsorption capacities, respectively. PMID:26717711

  16. Extreme-Risk Prostate Adenocarcinoma Presenting With Prostate-Specific Antigen (PSA) >40 ng/ml: Prognostic Significance of the Preradiation PSA Nadir

    SciTech Connect

    Alexander, Abraham S.; Mydin, Aminudin; Jones, Stuart O.; Christie, Jennifer; Lim, Jan T.W.; Truong, Pauline T.; Ludgate, Charles M.

    2011-12-01

    Purpose: To examine the impact of patient, disease, and treatment characteristics on survival outcomes in patients treated with neoadjuvant androgen deprivation therapy (ADT) and radical external-beam radiotherapy (RT) for clinically localized, extreme-risk prostate adenocarcinoma with a presenting prostate-specific antigen (PSA) concentration of >40 ng/ml. Methods and Materials: A retrospective chart review was conducted of 64 patients treated at a single institution between 1991 and 2000 with ADT and RT for prostate cancer with a presenting PSA level of >40 ng/ml. The effects of patient age, tumor (presenting PSA level, Gleason score, and T stage), and treatment (total ADT duration and pre-RT PSA level) characteristics on rates of biochemical disease-free survival (bDFS), prostate cancer-specific survival (PCSS), and overall survival (OS) were examined. Results: Median follow-up time was 6.45 years (range, 0.09-15.19 years). Actuarial bDFS, PCSS, and OS rates at 5 years were 39%, 87%, and 78%, respectively, and 17%, 64%, and 45%, respectively, at 10 years. On multivariate analysis, the pre-RT PSA level ({<=}0.1 versus >0.1 ng/ml) was the single most significant prognostic factor for bDFS (p = 0.033) and OS (p = 0.018) rates, whereas age, T stage, Gleason score, and ADT duration ({<=}6 versus >6 months) were not predictive of outcomes. Conclusion: In prostate cancer patients with high presenting PSA levels, >40 ng/ml, treated with combined modality, neoadjuvant ADT, and RT, the pre-RT PSA nadir, rather than ADT duration, was significantly associated with improved survival. This observation supports the use of neoadjuvant ADT to drive PSA levels to below 0.1 ng/ml before initiation of RT, to optimize outcomes for patients with extreme-risk disease.

  17. 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.

  18. 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. PMID:27282086

  19. Adsorption of organic molecules on silica surface.

    PubMed

    Parida, Sudam K; Dash, Sukalyan; Patel, Sabita; Mishra, B K

    2006-09-13

    The adsorption behaviour of various organic adsorbates on silica surface is reviewed. Most of the structural information on silica is obtained from IR spectral data and from the characteristics of water present at the silica surface. Silica surface is generally embedded with hydroxy groups and ethereal linkages, and hence considered to have a negative charged surface prone to adsorption of electron deficient species. Adsorption isotherms of the adsorbates delineate the nature of binding of the adsorbate with silica. Aromatic compounds are found to involve the pi-cloud in hydrogen bonding with silanol OH group during adsorption. Cationic and nonionic surfactants adsorb on silica surface involving hydrogen bonding. Sometimes, a polar part of the surfactants also contributes to the adsorption process. Styryl pyridinium dyes are found to anchor on silica surface in flat-on position. On modification of the silica by treating with alkali, the adsorption behaviour of cationic surfactant or polyethylene glycol changes due to change in the characteristics of silica or modified silica surface. In case of PEG-modified silica, adsolubilization of the adsorbate is observed. By using a modified adsorption equation, hemimicellization is proposed for these dyes. Adsorptions of some natural macromolecules like proteins and nucleic acids are investigated to study the hydrophobic and hydrophilic binding sites of silica. Artificial macromolecules like synthetic polymers are found to be adsorbed on silica surface due to the interaction of the multifunctional groups of the polymers with silanols. Preferential adsorption of polar adsorbates is observed in case of adsorbate mixtures. When surfactant mixtures are considered to study competitive adsorption on silica surface, critical micelle concentration of individual surfactant also contributes to the adsorption isotherm. The structural study of adsorbed surface and the thermodynamics of adsorption are given some importance in this review

  20. Volumetric interpretation of protein adsorption kinetics

    NASA Astrophysics Data System (ADS)

    Barnthip, Naris

    Protein adsorption is believed to be a very important factor ultimately leading to a predictive basis for biomaterials design and improving biocompatibility. Standard adsorption theories are modified to accommodate experimental observations. Adsorption from single-protein solutions and competitive adsorption from binary solutions are mainly considered. The standard solution-depletion method of measuring protein adsorption is implemented with SDS-gel electrophoresis as a multiplexing, separation-and-quantification tool to measure protein adsorption to hydrophobic octyl sepharose (OS) adsorbent particles. Standard radiometric methods have also been used as a further check on the electrophoresis method mentioned above for purified-protein cases. Experimental results are interpreted in terms of an alternative kinetic model called volumetric interpretation of protein adsorption. A partitioning process between bulk solution and a three-dimensional interphase region that separates bulk solution from the physical adsorbent surface is the concept of the model. Protein molecules rapidly diffuse into an inflating interphase that is spontaneously formed by bringing a protein solution into contact with a physical surface, then follows by rearrangement of proteins within this interphase to achieve the maximum interphase concentration (dictated by energetics of interphase dehydration) within the thinnest (lowest volume) interphase possible. An important role of water in protein adsorption is emphasized and supported by this model. The fundamental aspects including the reversibility/irreversibility of protein adsorption, the multilayer adsorption, the applicability of thermodynamic/computational models, the capacity of protein adsorption, and the mechanism of so called Vroman effect are discussed and compared to the conventional theories. Superhydrophobic effect on the adsorption of human serum albumin is also examined.

  1. NO Adsorption on Pd(111)

    NASA Astrophysics Data System (ADS)

    Garda, Graciela R.; Ferullo, Ricardo M.; Castellani, Norberto J.

    The reactive behavior of NO on Pd(111) has been studied using a semiempirical theoretical method. The adsorption sites and the related electronic structure have been considered. In particular, the dissociation process has been studied and compared with CO. Different dissociation mechanisms have been proposed and the formation of NCO species has been considered. The results follow the trends reported in the experimental literature.

  2. 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...

  3. 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

    2015-04-01

    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. PMID:25576782

  4. Electrochemical assay of active prostate-specific antigen (PSA) using ferrocene-functionalized peptide probes

    SciTech Connect

    Zhao, Ning; He, Yuqing; Mao, Xun; Sun, Yuhan; Zhang, Xibao; Li, Chen-Zhong; Lin, Yuehe; Liu, Guodong

    2010-03-24

    This paper presents a novel approach to electrochemically determine enzymatically active PSA using ferrocene-functionalized helix peptide (CHSSLKQK). The principle of electrochemical measurement is based on the specific proteolytic cleavage events of the FC-peptide on the gold electrode surface in the presence of PSA, resulting the change of the current signal of the electrode. The percentage of the decreased current is linear with the concentration of active PSA at the range of 0.5-40 ng/mL with a detection limit of 0.2 ng/mL. The direct transduction of peptide cleavage events into an electrical signal provides a simple, sensitive method for detecting the enzymatic activity of PSA and determining the active PSA concentration.

  5. First-year PSA kinetics and minima after prostate cancer radiotherapy are predictive of overall survival

    SciTech Connect

    Cheung, Rex . E-mail: mrcheung@mdanderson.org; Tucker, Susan L.; Kuban, Deborah A.

    2006-09-01

    Purpose: We analyzed whether first-year prostate-specific antigen (PSA) kinetics and minima are predictive of overall survival (OS). Methods and Materials: The data set contained 1,174 patients treated with external beam radiotherapy (RT) from 1987 to 2001. The relative rate of change ({lambda}) in post-RT PSA values during the first year (13.5 months) was computed using regression analysis of ln(PSA) vs. time. We also computed the PSA minimum (mPSA) reached during the same period. Recursive partitioning analysis was used to identify the relevant cutpoints for the factors being investigated for its association with survival: age, pretreatment PSA, radiation dose, relative rate of change in PSA post-RT, and 1-year PSA minimum. For each of the other factors stage, Gleason score and risk group, all possible cutpoints were considered in the multivariate analyses. Significant factors were considered in the multivariate analyses to identify independent predictors for overall survival. Results: The median value of {lambda} was -1.0 years{sup -1} (range, -11.0-5.1 years{sup -1}). The 1-year minimum had a median of 0.8 ng/mL (range, 0.01-30.9 ng/mL). Recursive partitioning analysis and Cox proportional hazards analyses identified the following pretreatment or treatment factors adversely related to OS: age, Gleason score, stage, and dose. First-year mPSA {>=} 4 ng/mL and {lambda} > 0 were post-RT independent prognostic factors for worse OS. Conclusion: First-year post-RT PSA kinetics and minima are early response parameters predictive of overall survival for prostate cancer patients. These factors may be useful in selecting patients for early salvage therapy.

  6. 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

    2016-01-01

    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

  7. Adsorption of pyridine by combusted oil shale

    NASA Astrophysics Data System (ADS)

    Essington, M. E.

    1992-03-01

    Large volumes of solid waste material will be produced during the commercial production of shale oil. An alternative to the disposal of the solid waste product is utilization. One potential use of spent oil shale is for the stabilization of hazardous organic compounds. The objective of this study was to examine the adsorption of pyridine, commonly found in oil shale process water, by spent oil shale. The adsorption of pyridine by fresh and weathered samples of combusted New Albany Shale and Green River Formation oil shale was examined. In general, pyridine adsorption can be classified as L-type and the isotherms modeled with the Langmuir and Freundlich equations. For the combusted New Albany Shale, weathering reduced the predicted pyridine adsorption maximum and increased the amount of pyridine adsorbed at low solution concentrations. For the combusted Green River Formation oil shales, weathering increased the predicted pyridine adsorption maximum. The pyridine adsorption isotherms were similar to those produced for a combusted Australian oil shale. Although adsorption can be mathematically described by empirical models, the reduction in solution concentrations of pyridine was generally less than 10 mg/l at an initial concentration of 100 mg/l. Clearly, the observed reduction in solution pyridine concentrations does not sufficiently justify using spent oil shale as a stabilizing medium. However, data in the literature suggest that other organic compounds can be effectively removed from solution by spent oil shale and that adsorption is dependent on process conditions and organic compound type.

  8. ``Losing the Dark:'' A Planetarium PSA about Light Pollution

    NASA Astrophysics Data System (ADS)

    Productions, L. N.; Walker, D. C.

    2013-04-01

    Losing the Dark is a PSA video being created for fulldome theaters by Loch Ness Productions under the direction of the International Dark Sky Association Education Committee headed by Dr. Constance Walker of the National Optical Astronomy Observatories. It explains the problems with light pollution, its effects on life, and three ways in which people can implement “wise lighting” practices to mitigate light pollution. The show is also being produced in a flat-screen HD format for use in classical planetarium and non-dome theaters, for presentations by IDA speakers when addressing planning boards, etc. and will be posted on the IDA and other web sites. The final length is six minutes for both versions. Funding has been provided by The International Planetarium Society and the International Dark-Sky Association.

  9. 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

  10. Surfactant adsorption to soil components and soils.

    PubMed

    Ishiguro, Munehide; Koopal, Luuk K

    2016-05-01

    Soils are complex and widely varying mixtures of organic matter and inorganic materials; adsorption of surfactants to soils is therefore related to the soil composition. We first discuss the properties of surfactants, including the critical micelle concentration (CMC) and surfactant adsorption on water/air interfaces, the latter gives an impression of surfactant adsorption to a hydrophobic surface and illustrates the importance of the CMC for the adsorption process. Then attention is paid to the most important types of soil particles: humic and fulvic acids, silica, metal oxides and layered aluminosilicates. Information is provided on their structure, surface properties and primary (proton) charge characteristics, which are all important for surfactant binding. Subsequently, the adsorption of different types of surfactants on these individual soil components is discussed in detail, based on mainly experimental results and considering the specific (chemical) and electrostatic interactions, with hydrophobic attraction as an important component of the specific interactions. Adsorption models that can describe the features semi-quantitatively are briefly discussed. In the last part of the paper some trends of surfactant adsorption on soils are briefly discussed together with some complications that may occur and finally the consequences of surfactant adsorption for soil colloidal stability and permeability are considered. When we seek to understand the fate of surfactants in soil and aqueous environments, the hydrophobicity and charge density of the soil or soil particles, must be considered together with the structure, hydrophobicity and charge of the surfactants, because these factors affect the adsorption. The pH and ionic strength are important parameters with respect to the charge density of the particles. As surfactant adsorption influences soil structure and permeability, insight in surfactant adsorption to soil particles is useful for good soil management. PMID

  11. 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. PMID:16852056

  12. 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. PMID:27391585

  13. PSA Screening for Prostate Cancer: Why Saying No is a High-Value Health Care Choice.

    PubMed

    Wilt, Timothy J; Dahm, Philipp

    2015-12-01

    Enthusiasm for cancer screening and treatment of screen-detected cancer has led to widespread prostate-specific antigen (PSA) screening, a marked increase in prostate cancer incidence, and high use of surgical, radiation, and androgen deprivation treatment for screen-detected disease. This has occurred in advance of a full understanding of the clinical and financial tradeoffs. Although questions remain whether lifetime benefits outweigh harms and costs, data indicate that this balance is not favorable through at least 15 years. This article outlines a conceptual framework for determining the value of screening strategies according to screening and treatment intensity. We describe 4 main cancer screening goals and examine whether PSA screening and treatment achieve these goals and thus provide high-value care. Available evidence demonstrates that PSA screening provides at best a small reduction in prostate cancer mortality, and no reduction in all-cause mortality. High-intensity PSA screening and treatment currently practiced in the United States result in substantial harms and large health care expenditures-it is low-value care. The health importance of prostate cancer and the financial costs to patients and society require improved detection and treatment strategies that produce greater value to patients. We propose lower-intensity, higher-value options. However, until evidence supports a higher-value alternative to current PSA screening strategies, physicians should recommend against PSA screening, policymakers should encourage reduced screening, and most men should say no to the PSA test. PMID:26656523

  14. 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.

  15. Efficacy of Salvage Radiotherapy Plus 2-Year Androgen Suppression for Postradical Prostatectomy Patients With PSA Relapse

    SciTech Connect

    Choo, Richard; Danjoux, Cyril; Gardner, Sandra; Morton, Gerard; Szumacher, Ewa; Loblaw, D. Andrew; Cheung, Patrick; Pearse, Maria

    2009-11-15

    Purpose: To determine the efficacy of a combined approach of radiotherapy (RT) plus 2-year androgen suppression (AS) as salvage treatment for prostate-specific antigen (PSA) relapse after radical prostatectomy (RP). Methods and Materials: Seventy-five patients with PSA relapse after RP were treated with salvage RT plus 2-year AS, as per a pilot, prospective study. AS started within 1 month after completion of salvage RT and consisted of nilutamide for 4 weeks and buserelin acetate depot subcutaneously every 2 months for 2 years. Relapse-free rate including freedom from PSA relapse was estimated using the Kaplan-Meier method. PSA relapse was defined as a PSA rise above 0.2 ng/mL with two consecutive increases over a minimum of 3 months. A Cox regression analysis was performed to evaluate prognostic factors for relapse. Results: Median age of the cohort was 63 years at the time of salvage RT. Median follow-up from salvage RT was 6.4 years. All achieved initially complete PSA response (< 0.2) with the protocol treatment. Relapse-free rate including the freedom from PSA relapse was 91.5% at 5 years and 78.6% at 7 years. Overall survival rate was 93.2% at both 5 and 7 years. On Cox regression analysis, pT3 stage and PSA relapse less than 2 years after RP were significant prognostic factors for relapse. Conclusion: The combined treatment of salvage RT plus 2-year AS yielded an encouraging result for patients with PSA relapse after RP and needs a confirmatory study.

  16. 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

  17. 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.

  18. [Adsorption characteristics of the antibiotic sulfanilamide onto rice husk ash].

    PubMed

    Ji, Ying-Xue; Wang, Feng-He; Zhang, Fan; Zhang, Yan-Hong; Wang, Guo-Xiang; Gu, Zhong-Zhu

    2013-10-01

    Under different conditions of initial rice husk ash (RHA) dosage, oscillating temperature, oscillating frequency and solution pH, the adsorption characteristics of sulfanilamide on RHA with the change of time and its adsorption kinetics were investigated. RHA was characterized by SEM and FTIR before and after sulfanilamide adsorption. The results indicated that the adsorption characteristics of sulfanilamide on RHA was influenced by RHA dosage, oscillating temperature, oscillating frequency and solution pH. Within the RHA dosing range (0. 1-2.0 g.L-1) in this experiment, the optimal temperature for the adsorption was 25C , and with the increase of RHA dosage, the removal efficiency of sulfanilamide increased, the time required to reach adsorption equilibrium was shortened and the adsorptive quantity of sulfanilamide by per unit mass of RHA decreased. A high oscillating frequency was used to ensure the adsorption effect when the RHA concentration was high. Strong acidic and strong alkaline conditions were conducive to the adsorption of sulfanilamide. The analysis of adsorption dynamics showed that for the adsorption process with high RHA dosage ( >or= 1.0 g.L-1), the pseudo-second-order model fitted the adsorption behavior well, and the process was controlled by physical and chemical adsorption. Intraparticle diffusion model showed that the adsorption process was controlled by both membrane diffusion and internal diffusion, and the influence of the former became more obvious with the increase of the adsorbent concentration. Both the SEM and FTIR spectra proved the effective adsorption of sulfanilamide by RHA. PMID:24364310

  19. Adsorption and excess fission xenon

    NASA Technical Reports Server (NTRS)

    Podosek, F. A.; Bernatowicz, T. J.; Kramer, F. E.

    1982-01-01

    The adsorption of Xe and Kr on lunar soil 10084 was measured by a method that employs only very low fractions of monolayer coverage. Results are presented as parameters for calculation of the Henry constant for adsorption as a function of temperature. The adsorption potentials are about 3 kcal/mole for Kr and 5 kcal/mole for Xe; heating the sample in vacuum increased the Xe potential to nearly 7 kcal/mole. Henry constants at the characteristic lunar temperature are about 0.3 cu cm STP/g-atm. These data were applied to consider whether adsorption is important in producing the excess fission Xe effect characteristic of highland breccias. Sorption equilibrium with a transient lunar atmosphere vented fission Xe produces concentrations seven orders of magnitude lower than observed concentrations. Higher concentrations result because of the resistance of the regolith to upward diffusion of Xe. A diffusion coefficient of 0.26 sq cm/sec is estimated for this process.

  20. Characterization of the Prostate-Specific Antigen (PSA) Catalytic Mechanism: A Pre-Steady-State and Steady-State Study

    PubMed Central

    Tomao, Luigi; Sbardella, Diego; Gioia, Magda; Di Masi, Alessandra; Marini, Stefano; Ascenzi, Paolo; Coletta, Massimo

    2014-01-01

    Prostate-specific antigen (PSA), an enzyme of 30 kDa grouped in the kallikrein family is synthesized to high levels by normal and malignant prostate epithelial cells. Therefore, it is the main biomarker currently used for early diagnosis of prostate cancer. Here, presteady-state and steady-state kinetics of the PSA-catalyzed hydrolysis of the fluorogenic substrate Mu-His-Ser-Ser-Lys-Leu-Gln-AMC (spanning from pH 6.5 to pH 9.0, at 37.0°C) are reported. Steady-state kinetics display at every pH value a peculiar feature, represented by an initial “burst” phase of the fluorescence signal before steady-state conditions are taking place. This behavior, which has been already observed in other members of the kallikrein family, suggests the occurrence of a proteolytic mechanism wherefore the acylation step is faster than the deacylation process. This feature allows to detect the acyl intermediate, where the newly formed C-terminal carboxylic acid of the cleaved substrate forms an ester bond with the -OH group of the Ser195 catalytic residue, whereas the AMC product has been already released. Therefore, the pH-dependence of the two enzymatic steps (i.e., acylation and deacylation) has been separately characterized, allowing the determination of pKa values. On this basis, possible residues are tentatively identified in PSA, which might regulate these two steps by interacting with the two portions of the substrate. PMID:25068395

  1. 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.

  2. Random sequential adsorption of trimers and hexamers.

    PubMed

    Cieśla, Michał; Barbasz, Jakub

    2013-12-01

    Adsorption of trimers and hexamers built of identical spheres was studied numerically using the random sequential adsorption (RSA) algorithm. Particles were adsorbed on a two-dimensional, flat and homogeneous surface. Numerical simulations allowed us to determine the maximal random coverage ratio, RSA kinetics as well as the available surface function (ASF), which is crucial for determining the kinetics of the adsorption process obtained experimentally. Additionally, the density autocorrelation function was measured. All the results were compared with previous results obtained for spheres, dimers and tetramers. PMID:24193213

  3. 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

  4. 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

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

    PubMed

    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

  6. Adsorption of ferrous ions onto montmorillonites

    NASA Astrophysics Data System (ADS)

    Qin, Dawei; Niu, Xia; Qiao, Min; Liu, Gang; Li, Hongxin; Meng, Zhenxiao

    2015-04-01

    The adsorption of Fe (II) onto montmorillonites was investigated through initial concentration, contact time, pH and temperature. During the whole adsorption process, the ascorbic acid (Vitamin C) was added as a kind of antioxidant, at the same time, deionized water (after boiling) and nitrogen protection were also used to avoid oxidation. The Fe2+/Fetotal ratio of the iron exists in the Fe-montmorillonites was found more than 95%. Two kinetic models, including pseudo-first-order and pseudo-second-order model, were used to analyze the adsorption process of Fe (II) on montmorillonites. The results of our study showed that adsorption process fitted with pseudo-second-order well. Adsorption isotherms showed that Langmuir model was better than Freundlich model. The thermodynamic parameters ΔG0 and ΔH0 were 3.696 kJ/mol and 6.689 kJ/mol (we just gave the values at 298 K), respectively. The positive values at different temperatures showed that the adsorption process was non-spontaneous and endothermic. The characteristics of materials were determined by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Surface area and porosity analyzer, Thermogravimetric analysis (TGA), Differential scanning calorimeter (DSC) and Zeta potential distribution.

  7. 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

  8. 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.

  9. 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.

  10. 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. PMID:24994954

  11. 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.

  12. 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…

  13. Effects of the surface concentration of fixed charges in C18-bonded stationary phases on the adsorption process and on the preparative chromatography of small ionizable compounds.

    PubMed

    Gritti, Fabrice; Guiochon, Georges

    2014-11-01

    The effects of the surface concentration of positive charges attached to the surface of research BEH-C18 hybrid particles on the overloaded band profiles and the adsorption isotherms of a neutral (caffeine) and a positively charged (nortryptilinium hydrochloride) compounds were measured and investigated. The inverse method (IM) of chromatography was used to determine the isotherm parameters. Three columns were packed with endcapped BEH-C18 particles doped with three different charge densities on their surfaces (LOW, MEDIUM and HIGH). Two other columns packed with unbonded, non-endcapped, and endcapped BEH-C18 particles served as standard reference materials. Minor disturbance method (MDM) experiments were conducted with acetonitrile/water mixtures in order to assess qualitatively the surface densities of the fixed positive charges. A more quantitative approach based on the solution of the linearized Poisson-Boltzmann equation and the decrease of the experimental Henry constant was also applied. The results show that the surface concentrations of the fixed charges in the LOW, MEDIUM and HIGH columns were 0.029, 0.050, and 0.064μmol/m(2), e.g., close to two orders of magnitude smaller than the surface density of bonded C18 chains (2.1μmol/m(2)). The adsorption isotherm of the ionizable compound nortryptilinium onto the BEH-C18 columns is consistent with a two-sites adsorption model. The density of the high energy sites correlates directly to the total amount of the fixed charges and isolated silanols amidst the C18-bonded chains. The amount of low energy sites reflects the specific surface area of the adsorbent. The binding constants on the high- and low-energy adsorption sites are respectively ten and two times lower on the HIGH column than on the reference endcapped column. The active sites are closer to the adsorbent surface than the weak adsorption sites. Finally, a higher production rate of ionizable compounds can be achieved in preparative chromatography with

  14. Evaluation of postradiotherapy PSA patterns and correlation with 10-year disease free survival outcomes for prostate cancer

    SciTech Connect

    Zelefsky, Michael J. . E-mail: zelefskm@mskcc.org; Ben-Porat, Leah; Chan, Heather M.; Fearn, Paul A.; Venkatraman, Ennapadam S.

    2006-10-01

    Purpose: To describe the prostate-specific antigen (PSA) pattern profiles observed after external beam radiotherapy with and without short-term neoadjuvant androgen deprivation therapy (ST-ADT) and to report the association of established posttreatment PSA patterns with long-term disease-free survival outcomes. Methods and Materials: A total of 1,665 patients were treated with conformal external beam radiotherapy for clinically localized prostate cancer. Of 570 patients who had the requisite >10 consecutive PSA measurements for statistical analysis, 194 patients received a median of 3 months of ADT before radiotherapy and 376 were treated with radiotherapy alone. The median follow up was 103 months. Results: In the group treated with ST-ADT, three distinct postradiotherapy PSA patterns were identified: a stable trend (44%), an increasing trend followed by stabilization of the PSA (25%), and an increasing trend (31%). Among the subgroup that demonstrated a rising and subsequent stabilizing patterns, PSA levels had gradually risen to a median value of 0.9 ng/mL after therapy, stabilized, and remained durably suppressed. The only identified trends among patients treated with external beam radiotherapy without ST-ADT were declining PSA levels followed by stable PSA trends or declining patterns followed by rising levels. Patients whose PSA levels stabilized after an initial rise or those with slowly rising PSA profiles had a lower incidence of distant metastasis compared to those with accelerated rises after therapy. Conclusions: For those treated with external beam radiotherapy in conjunction with ST-ADT, a significant percentage who develop a rising PSA after treatment are expected to manifest subsequent stabilization at plateaued levels of approximately 1.0 ng/mL, which can remain durably suppressed. The likelihood of distant metastasis in these patients is low despite the PSA stabilization at levels 1.0 ng/mL or higher and comparable to outcomes observed for those

  15. 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. PMID:17980962

  16. Selective adsorption and efficient regeneration via smart adsorbents possessing thermo-controlled molecular switches.

    PubMed

    Jiang, Yao; Tan, Peng; Cheng, Lei; Shan, Shu-Feng; Liu, Xiao-Qin; Sun, Lin-Bing

    2016-04-21

    Adsorption and desorption are equally important in an adsorptive separation process, while conventional adsorbents with fixed pores benefit only one of them rather than both. Here, a new generation of adsorbents was fabricated by incorporating thermo-responsive polymers (TRPs) into pores. The TRPs act as molecular switches, making pore spaces and active sites responsive to adsorption/desorption conditions. The adsorbents can thus realize both selective adsorption and efficient desorption, which are extremely desirable for adsorptive separation. PMID:26883022

  17. Calcium lignosulfonate adsorption and desorption on Berea sandstone.

    PubMed

    Grigg, Reid B; Bai, Baojun

    2004-11-01

    This paper describes adsorption and desorption studies carried out with calcium lignosulfonate (CLS) on Berea sandstone. Circulation experiments were performed to determine CLS adsorption isotherms and the effects of CLS concentration, temperature, salinity, brine hardness, and injection rate on adsorption density. Flow-through experiments were performed to assess the reversibility of CLS adsorption and the influence of postflush rate, brine concentration, brine hardness, brine pH, and temperature on the desorption process. Results indicate that CLS adsorption isotherms on Berea sandstone follow the Freundlich isotherm law. The results presented in this paper on the effects of CLS adsorption and desorption on Berea sandstone show that: (1) increasing CLS concentration and salinity increases CLS adsorption density; (2) increasing temperature will decrease adsorption density; (3) increasing injection rate of CLS solution will slightly decrease CLS adsorption density; (4) postflush rate and salinity of brine have a large impact on the CLS desorption process; (5) the adsorption and desorption process are not completely reversible; and (5) temperature and pH of the postflush brine have little effect on desorption. PMID:15380409

  18. Adsorptive properties of flyash carbon

    SciTech Connect

    Graham, U.M.; Rathbone, R.F.; Robl, T.L.

    1996-10-01

    Flyash carbon constitutes the char particles that are left in flyash after the incomplete combustion of coal in the furnace, rendering flyash above spec for ASTM C618 applications for cement. A beneficiation process allows the selective separation of unburned carbon from flyash to be used for upgrading into a higher value product. Flyash carton is composed of several microscopically distinguishable types; inertinite is relatively unreactive in the thermal processing of coal and occurs essentially unaltered in the flyash while {open_quotes}coke{close_quotes} is produced from the melting, devolatilization, swelling and resolidification of the reactive macerals vitrinite and liptinite. The porosity, surface area, and surface chemistry of flyash carbons are characterized using mercury porosimetry, BET analysis, and vapor- and liquid-phase adsorption of various organic compounds. Results suggest that different carbon forms in flyash affect the degree of adsorption of phenols as will as other hydrocarbon pollutants onto the flyash carbon. A comparison of adsorptability of the flyash carbon compared to commercially available active carbons are discussed.

  19. Adsorption kinetics of diatomic molecules.

    PubMed

    Burde, Jared T; Calbi, M Mercedes

    2014-05-01

    The adsorption dynamics of diatomic molecules on solid surfaces is examined by using a Kinetic Monte Carlo algorithm. Equilibration times at increasing loadings are obtained, and explained based on the elementary processes that lead to the formation of the adsorbed film. The ability of the molecules to change their orientation accelerates the overall uptake and leads to competitive kinetic behaviour between the different orientations. The dependence of the equilibration time on coverage follows the same decreasing trend obtained experimentally for ethane adsorption on closed-end carbon nanotube bundles. The exploration of molecule-molecule interaction effects on this trend provides relevant insights to understand the kinetic behaviour of other species, from simpler molecules to larger polyatomic molecules, adsorbing on surfaces with different binding strength. PMID:24654004

  20. 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

  1. 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. PMID:27294671

  2. 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

  3. 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. PMID:21179969

  4. Efficient adsorption of phenanthrene by simply synthesized hydrophobic MCM-41 molecular sieves

    NASA Astrophysics Data System (ADS)

    Hu, Yun; He, Yinyun; Wang, Xiaowen; Wei, Chaohai

    2014-08-01

    Hydrophobic molecular sieve MCM-41 including surfactant template was synthesized by a simple method. The adsorption properties of this material toward phenanthrene were studied. The effects of adsorbent dose and pH value on the adsorption process as well as the adsorption mechanism and reuse performance were investigated. The template-containing MCM-41 showed a significant adsorption for phenanthrene, due to its hydrophobicity created by the surfactant template in MCM-41. The solution pH had little effect on the adsorption capacity. The adsorption kinetic could be fitted well with pseudo-second-order kinetic model. The adsorption equilibrium was fitted well by the linear model, and the adsorption process followed the liquid/solid phase distribution mechanism. The thermodynamic results indicated that the adsorption was a spontaneous and exothermic process.

  5. 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

  6. Electronic phenomena in adsorption and catalysis

    SciTech Connect

    Kiselev, V.F.; Krylov, O.V.

    1987-01-01

    This book is the second of a three-volume treatment prepared by a physicist and a chemist, who took a common standpoint in considering the close relationship between the electronic processes taking place on the semiconductor-dielectric interface on the one hand, and the adsorptive and catalytic phenomena on the other. This volume brings together, and generalizes, a vast bulk of knowledge on the nature of surface and interface states, on the mechanism of surface electronic processes in semiconductors, as well as considers ways of controlling these processes. In addition, the authors discuss plausible mechanisms of elementary acts in surface charging during adsorption and catalysis.

  7. Influence of Ca2+ on tetracycline adsorption on montmorillonite.

    PubMed

    Parolo, M Eugenia; Avena, Marcelo J; Pettinari, Gisela R; Baschini, Miria T

    2012-02-15

    The adsorption of tetracycline (TC) on montmorillonite was studied as a function of pH and Ca(2+) concentration using a batch technique complemented with X-ray diffraction and transmission electron microscopy. In the absence of Ca(2+), TC adsorption was high at low pH and decreased as the pH increased. In the presence of Ca(2+), at least two different adsorption processes took place in the studied systems, i.e., cation exchange and Ca-bridging. Cation exchange was the prevailing process at pH<5, and thus, TC adsorption decreased by increasing total Ca(2+) concentration. On the contrary, Ca-bridging was the prevailing process at pH>5, and thus, TC adsorption increased by increasing Ca(2+) concentration. The pH 5 represents an isoadsorption pH where both adsorption processes compensate each other. TC adsorption became independent of Ca(2+) concentration at this pH. For TC adsorption on Ca(2+)-montmorillonite in 0.01 M NaCl experiments, the ratio adsorbed TC/retained Ca(2+) was close to 1 in the pH range of 5-9, indicating an important participation of Ca(2+) in the binding of TC to montmorillonite. X-ray diffraction and transmission electron microscopy showed that TC adsorption induced intercalation between montmorillonite layers forming a multiphase system with stacking of layers with and without intercalated TC. PMID:22189389

  8. Urine TMPRSS2:ERG fusion transcript stratifies prostate cancer risk in men with elevated serum PSA

    PubMed Central

    Tomlins, Scott A.; Aubin, Sheila M. J.; Siddiqui, Javed; Lonigro, Robert J.; Sefton-Miller, Laurie; Miick, Siobhan; Williamsen, Sarah; Hodge, Petrea; Meinke, Jessica; Blase, Amy; Penabella, Yvonne; Day, John R.; Varambally, Radhika; Han, Bo; Wood, David; Wang, Lei; Sanda, Martin G.; Rubin, Mark A.; Rhodes, Daniel R.; Hollenbeck, Brent; Sakamoto, Kyoko; Silberstein, Jonathan L.; Fradet, Yves; Amberson, James B.; Meyers, Stephanie; Palanisamy, Nallasivam; Rittenhouse, Harry; Wei, John T.; Groskopf, Jack; Chinnaiyan, Arul M.

    2011-01-01

    More than 1,000,000 men undergo prostate biopsy each year in the United States, most for “elevated” serum prostate specific antigen (PSA). Given the lack of specificity and unclear mortality benefit of PSA testing, methods to individualize management of elevated PSA are needed. Greater than 50% of PSA-screened prostate cancers harbor fusions between the transmembrane protease, serine 2 (TMPRSS2) and v-ets erythroblastosis virus E26 oncogene homolog (avian) (ERG) genes. Here, we report a clinical-grade, transcription-mediated amplification assay to risk stratify and detect prostate cancer noninvasively in urine. The TMPRSS2:ERG fusion transcript was quantitatively measured in prospectively collected whole urine from 1312 men at multiple centers. Urine TMPRSS2:ERG was associated with indicators of clinically significant cancer at biopsy and prostatectomy, including tumor size, high Gleason score at prostatectomy, and upgrading of Gleason grade at prostatectomy. TMPRSS2:ERG, in combination with urine prostate cancer antigen 3 (PCA3), improved the performance of the multivariate Prostate Cancer Prevention Trial risk calculator in predicting cancer on biopsy. In the biopsy cohorts, men in the highest and lowest of three TMPRSS2:ERG+PCA3 score groups had markedly different rates of cancer, clinically significant cancer by Epstein criteria, and high-grade cancer on biopsy. Our results demonstrate that urine TMPRSS2:ERG, in combination with urine PCA3, enhances the utility of serum PSA for predicting prostate cancer risk and clinically relevant cancer on biopsy. PMID:21813756

  9. 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. PMID:24989886

  10. Changes in PSA Kinetics Predict Metastasis-Free Survival in Men with PSA-Recurrent Prostate Cancer Treated with Non-Hormonal Agents: Combined Analysis of 4 Phase II Trials

    PubMed Central

    Antonarakis, Emmanuel S.; Zahurak, Marianna L.; Lin, Jianqing; Keizman, Daniel; Carducci, Michael A.; Eisenberger, Mario A.

    2011-01-01

    Background Several phase II trials in men with non-castrate PSA-recurrent prostate cancer have assessed the impact of novel non-hormonal agents on PSA kinetics. However, it is unknown whether changes in PSA kinetics influence metastasis-free survival (MFS). Methods We performed a retrospective post hoc analysis of 146 men treated in four phase II trials examining the investigational agents marimastat (a matrix metalloproteinase inhibitor; n=39), imatinib (a tyrosine kinase inhibitor; n=25), ATN-224 (a copper/zinc-superoxide dismutase inhibitor; n=22), and lenalidomide (an antiangiogenic/immunomodulatory drug; n=60). We investigated factors influencing MFS, including within-subject changes in PSA kinetics (PSA slope, doubling time, and velocity) before and after treatment initiation. Results After a median follow-up of 16.8 months, 70 patients (47.9%) developed metastases. In multivariable Cox regression models, factors that were independently predictive of MFS after adjusting for age and other clinical prognostic variables were baseline PSA doubling time (PSADT) (P=.05), baseline PSA slope (P=.01), on-study change in PSADT (P=.02), and on-study change in PSA slope (P=.03). In a landmark Kaplan-Meier analysis, median MFS was 63.5 months (95% CI 34.6–not reached) and 28.9 months (95% CI 13.5–68.0) for men with or without any decrease in PSA slope by 6 months after treatment, respectively. Conclusions This hypothesis-generating analysis suggests that within-subject changes in PSADT and PSA slope after initiation of experimental therapy may correlate with MFS in men with biochemically-recurrent prostate cancer. If validated in prospective trials, changes in PSA kinetics may represent a reasonable intermediate endpoint for screening new agents in these patients. PMID:21960118

  11. Adsorption of chlorophenols on granular activated carbon

    SciTech Connect

    Yang, M.

    1993-12-31

    Studies were undertaken of the adsorption of chlorinated phenols from aqueous solution on granular activated carbon (Filtrasorb-400, 30 x 40 mesh). Single-component equilibrium adsorption data on the eight compounds in two concentration ranges at pH 7.0 fit the Langmuir equation better than the Freundlich equation. The adsorptive capacities at pH 7.0 increase from pentachlorophenol to trichlorophenols and are fairly constant from trichlorophenols to monochlorophenols. The adsorption process was found to be exothermic for pentachlorophenol and 2,4,6-trichlorophenol, and endothermic for 2,4-dichlorophenol and 4-chlorophenol. Equilibrium measurements were also conducted for 2,4,5-trichlorophenol, 2,4-dichlorophenol, and 4-chlorophenol over a wide pH range. A surface complexation model was proposed to describe the effect of pH on adsorption equilibria of chlorophenols on activated carbon. The simulations of the model are in excellent agreement with the experimental data. Batch kinetics studies were conducted of the adsorption of chlorinated phenols on granular activated carbon. The results show that the surface reaction model best describes both the short-term and long-term kinetics, while the external film diffusion model describes the short-term kinetics data very well and the linear-driving-force approximation improved its performance for the long-term kinetics. Multicomponent adsorption equilibria of chlorophenols on granular activated carbon was investigated in the micromolar equilibrium concentration range. The Langmuir competitive and Ideal Adsorbed Solution (IAS) models were tested for their performance on the three binary systems of pentachlorophenol/2,4,6-trichlorophenol, 2,4,6-trichlorophenol/2,4-dichlorophenol, and 2,4-dichlorophenol/4-chlorophenol, and the tertiary system of 2,4,6-trichlorophenol/2,4-dichlorophenol/4-chlorophenol, and found to fail to predict the two-component adsorption equilibria of the former two binary systems and the tertiary system.

  12. 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.

  13. Toluene removal by sequential adsorption-plasma catalytic process: Effects of Ag and Mn impregnation sequence on Ag-Mn/γ-Al2O3.

    PubMed

    Qin, Caihong; Huang, Xuemin; Dang, Xiaoqing; Huang, Jiayu; Teng, Jingjing; Kang, Zhongli

    2016-11-01

    A series of Ag-Mn/γ-Al2O3 were prepared under different Ag/Mn impregnation sequence and tested in the sequential adsorption-plasma catalytic removal of toluene. When Mn was impregnated first, the resulting catalyst, Ag-Mn(F)/γ-Al2O3, had longer breakthrough time, gave less emission of toluene, had higher CO2 selectivity, and had better carbon balance and COx yield compared to catalysts prepared via other impregnation sequences. After 120 min of NTP treatment, the carbon balance of Ag-Mn(F)/γ-Al2O3 was 91%, with 87% as COx contributions. A Brunauer-Emmett-Teller (BET) analysis and X-ray photoelectron spectroscopy (XPS) results show that, the impregnation sequence impacts the BET surface area and the ratio and existing state of Ag on the surface of the catalysts. The longer breakthrough time when using Ag-Mn(F)/γ-Al2O3 as catalyst is attributed to the large amount of Ag(+) on the surface. Ag(+) is a new active site for toluene adsorption. When Ag was impregnated first (Ag(F)-Mn/γ-Al2O3) or Ag and Mn co-impregnated (Ag-Mn-C/γ-Al2O3), the predominant specie was Ag(+). Both Ag(0) and Ag(+) species were detected on Ag-Mn(F)/γ-Al2O3. Ag(0) cooperation with MnOx may promote the migration of surface active oxygen. This would facilitate the oxidation of adsorbed toluene with CC bond already weakened by Ag(+) and would result in higher CO2 selectivity and better carbon balance as seen in the Ag-Mn(F)/γ-Al2O3 system. PMID:27494312

  14. Isolation and characterization of wild-type lipoxygenase LOX(Psa)1 from Pleurotus sapidus.

    PubMed

    Plagemann, Ina; Krings, Ulrich; Berger, Ralf G

    2014-01-01

    The lipoxygenase LOX(Psa) 1 of Pleurotus sapidus, originally investigated because of its ability to oxidize (+)-valencene to the valuable grapefruit aroma (+)-nootkatone, was isolated from the peptidase-rich lyophilisate using a three-step purification scheme including preparative isoelectric focusing and chromatographic techniques. Nano-liquid chromatography electrospray ionization tandem mass spectrometry (nLC-ESI-MS/MS) of the purified enzyme and peptide mass fingerprint analysis gave 38 peptides of the lipoxygenase from P. sapidus. Nearly 50% of the 643 amino acids long sequence encoded by the cDNA was covered. Both terminal peptides of the native LOX(Psa) 1 were identified by de novo sequencing, and the postulated molecular mass of 72.5 kDa was confirmed. With linoleic acid as the substrate, the LOX(Psa)1 showed a specific activity of 113 U mg(-1) and maximal activity at pH 7.0 and 30 degrees C, respectively. PMID:24873036

  15. Microscopic Theory of Hysteretic Hydrogen Adsorption in Nanoporous Materials

    SciTech Connect

    Kang, J.; Wei, S. H.; Kim, Y. H.

    2010-01-01

    Understanding gas adsorption confined in nanoscale pores is a fundamental issue with broad applications in catalysis and gas storage. Recently, hysteretic H{sub 2} adsorption was observed in several nanoporous metal-organic frameworks (MOFs). Here, using first-principles calculations and simulated adsorption/desorption isotherms, we present a microscopic theory of the enhanced adsorption hysteresis of H{sub 2} molecules using the MOF Co(1,4-benzenedipyrazolate) [Co(BDP)] as a model system. Using activated H{sub 2} diffusion along the small-pore channels as a dominant equilibration process, we demonstrate that the system shows hysteretic H{sub 2} adsorption under changes of external pressure. For a small increase of temperature, the pressure width of the hysteresis, as well as the adsorption/desorption pressure, dramatically increases. The sensitivity of gas adsorption to temperature changes is explained by the simple thermodynamics of the gas reservoir. Detailed analysis of transient adsorption dynamics reveals that the hysteretic H{sub 2} adsorption is an intrinsic adsorption characteristic in the diffusion-controlled small-pore systems.

  16. 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

  17. 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.

  18. 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.

  19. Microcystin-LR Adsorption by Activated Carbon.

    PubMed

    Pendleton, Phillip; Schumann, Russell; Wong, Shiaw Hui

    2001-08-01

    We use a selection of wood-based and coconut-based activated carbons to investigate the factors controlling the removal of the hepatotoxin microcystin-LR (m-LR) from aqueous solutions. The wood carbons contain both micropores and mesopores. The coconut carbons contain micropores only. Confirming previously published observations, we also find that the wood-based carbons adsorb more microcystin than the coconut-based carbons. From a combination of a judicious modification of a wood-based carbon's surface chemistry and of the solution chemistry, we demonstrate that both surface and solution chemistry play minor roles in the adsorption process, with the adsorbent surface chemistry exhibiting less influence than the solution chemistry. Conformational changes at low solution pH probably contribute to the observed increase in adsorption by both classes of adsorbent. At the solution pH of 2.5, the coconut-based carbons exhibit a 400% increased affinity for m-LR compared with 100% increases for the wood-based carbons. In an analysis of the thermodynamics of adsorption, using multiple temperature adsorption chromatography methods, we indicate that m-LR adsorption is an entropy-driven process for each of the carbons, except the most hydrophilic and mesoporous carbon, B1. In this case, exothermic enthalpy contributions to adsorption also exist. From our overall observations, since m-LR contains molecular dimensions in the secondary micropore width range, we demonstrate that it is important to consider both the secondary micropore and the mesopore volumes for the adsorption of m-LR from aqueous solutions. Copyright 2001 Academic Press. PMID:11446779

  20. Influence of calcium of the adsorption properties of EOR polymers

    SciTech Connect

    Lee, L.T.; Lecourtier, J.; Chauveteau, G. )

    1988-05-01

    A controlling factor in the success of polymer flooding in enhanced oil recovery (EOR) is the adsorption of polymers on reservoir rocks. Polymer adsorption depletes polymer from the mobility control slug, leading to delayed oil recovery and thus rendering the EOR process un-economical. Although there has been extensive research in the field of polymer adsorption, a comprehensive study of adsorption of high molecular weight EOR polymers under imposed field conditions have been few. One of the commonly encountered conditions is the presence of high levels of monovalent and multivalent ions which can interact with both polymers and solid surfaces, hence complicating further the adsorption process. Others have dealt mainly with methodologies for determining the adsorption of both polyacrylamides and xanthan on mineral surfaces, and the influence of pH and monovalent ions on adsorption of these polymers. This study aims at determining the effects of divalent ions, namely calcium, on the adsorption of polyacrylamides and xanthan on mineral supports. In addition, the solution behavior of the polymers in the presence of calcium is investigated and related to the adsorption properties.

  1. Modeling tailed bacteriophage adsorption: Insight into mechanisms.

    PubMed

    Storms, Zachary J; Sauvageau, Dominic

    2015-11-01

    The process of a bacteriophage attaching to its host cell is a combination of physical diffusion, biochemical surface interactions, and reaction-induced conformational changes in receptor proteins. Local variations in the physico-chemical properties of the medium, the phage׳s mode of action, and the physiology of the host cell also all influence adsorption kinetics. These characteristics can affect a specific phage׳s binding capabilities and the susceptibility of the host cell to phage attack. Despite the complexity of this process, describing adsorption kinetics of a population of bacteriophages binding to a culture of cells has been accomplished with relatively simple equations governed by the laws of mass-action. Many permutations and modifications to the basic set of reactions have been suggested through the years. While no single solution emerges as a universal answer, this review provides the fundamentals of current phage adsorption modeling and will guide researchers in the selection of valid, appropriate models. PMID:26331682

  2. Kinetic study of lead adsorption to composite biopolymer adsorbent

    SciTech Connect

    Seki, H.; Suzuki, A.

    1999-03-15

    A kinetic study of lead adsorption to composite biopolymer adsorbents was carried out. Spherical and membranous adsorbents containing two biopolymers, humic acid and alginic acid, were used for lead adsorption in dilute acidic solutions. The shrinking core model derived by M.G. Rao and A.K. Gupta was applied to describe the rate process of lead adsorption to spherical adsorbents (average radii of 0.12, 0.15, and 0.16 cm). Furthermore, the shrinking core model was modified and adapted for description of the rate process of lead adsorption to membranous adsorbent (average thickness of 0.0216 cm). The adsorption rate process for both the cases was well described and average apparent lead diffusion coefficients of about 6 {times} 10{sup {minus}6} and 7 {times} 10{sup {minus}6} cm{sup 2}/s were found for the spherical and membranous adsorbents, respectively.

  3. Kinetic Study of Lead Adsorption to Composite Biopolymer Adsorbent.

    PubMed

    Seki; Suzuki

    1999-03-15

    A kinetic study of lead adsorption to composite biopolymer adsorbents was carried out. Spherical and membranous adsorbents containing two biopolymers, humic acid and alginic acid, were used for lead adsorption in dilute acidic solutions. The shrinking core model derived by M. G. Rao and A. K. Gupta (Chem. Eng. J. 24, 181, 1982) was applied to describe the rate process of lead adsorption to spherical adsorbents (average radii of 0.12, 0.15, and 0.16 cm). Furthermore, the shrinking core model was modified and adapted for description of the rate process of lead adsorption to membranous adsorbent (average thickness of 0.0216 cm). The adsorption rate process for the both cases was well described and average apparent lead diffusion coefficients of about 6 x 10(-6) and 7 x 10(-6) cm2 s-1 were found for the spherical and membranous adsorbents, respectively. Copyright 1999 Academic Press. PMID:10049553

  4. 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.

  5. 40 CFR 796.2750 - Sediment and soil adsorption isotherm.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 31 2010-07-01 2010-07-01 true Sediment and soil adsorption isotherm. 796.2750 Section 796.2750 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) CHEMICAL FATE TESTING GUIDELINES Transport Processes § 796.2750 Sediment and soil adsorption isotherm....

  6. Superior adsorption of pharmaceutical molecules by highly porous BN nanosheets.

    PubMed

    Liu, Dan; Lei, Weiwei; Qin, Si; Klika, Karel D; Chen, Ying

    2016-01-01

    Highly porous boron nitride nanosheets (BNNSs) were tested as a re-usable adsorbent for the removal of pharmaceuticals from aqueous solution. The BNNSs exhibit both unprecedentedly high adsorption capacities and excellent recyclability while maintaining their high adsorption capacity by a simple regeneration process. These advantages render BNNSs a promising material for water remediation applications. PMID:26618906

  7. 40 CFR 796.2750 - Sediment and soil adsorption isotherm.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... to sediments and soils is an important process that affects a chemical's distribution in the.... “Adsorption, desorption of parathion as affected by soil organic matter,” Journal of Agricultural and Food... 40 Protection of Environment 32 2014-07-01 2014-07-01 false Sediment and soil adsorption...

  8. 40 CFR 796.2750 - Sediment and soil adsorption isotherm.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... to sediments and soils is an important process that affects a chemical's distribution in the.... “Adsorption, desorption of parathion as affected by soil organic matter,” Journal of Agricultural and Food... 40 Protection of Environment 33 2012-07-01 2012-07-01 false Sediment and soil adsorption...

  9. 40 CFR 796.2750 - Sediment and soil adsorption isotherm.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... to sediments and soils is an important process that affects a chemical's distribution in the.... “Adsorption, desorption of parathion as affected by soil organic matter,” Journal of Agricultural and Food... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Sediment and soil adsorption...

  10. 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

  11. 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. PMID:12628792

  12. 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). PMID:27191561

  13. Process optimization of deposition conditions of PbS thin films grown by a successive ionic layer adsorption and reaction (SILAR) method using response surface methodology

    NASA Astrophysics Data System (ADS)

    Yücel, Ersin; Yücel, Yasin; Beleli, Buse

    2015-07-01

    In this study, lead sulfide (PbS) thin films were synthesized by a successive ionic layer adsorption and reaction (SILAR) method with different pH, dipping time and dipping cycles. Response surface methodology (RSM) and central composite design (CCD) were successfully used to optimize the PbS films deposition parameters and understand the significance and interaction of the factors affecting the film quality. 5-level-3-factor central composite design was employed to evaluate the effects of the deposition parameters (pH, dipping time and dipping cycles) on the response (the optical band gap of the films). Data obtained from RSM were subjected to the analysis of variance (ANOVA) and analyzed using a second order polynomial equation. The optimal conditions for the PbS films deposition have been found to be: pH of 9.1, dipping time of 10 s and dipping cycles of 10 cycles. The predicted band gap of PbS film was 2.13 eV under the optimal conditions. Verification experiment (2.24 eV) confirmed the validity of the predicted model. The film structures were characterized by X-ray diffractometer (XRD). Morphological properties of the films were studied with a scanning electron microscopy (SEM). The optical properties of the films were investigated using a UV-visible spectrophotometer.

  14. 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. PMID:21831394

  15. Diesel NO(x) aftertreatment by combined process using temperature swing adsorption, NO(x) reduction by nonthermal plasma, and NO(x) recirculation: improvement of the recirculation process.

    PubMed

    Yoshida, Keiichiro; Kuwahara, Takuya; Kuroki, Tomoyuki; Okubo, Masaaki

    2012-09-15

    NO(x) emitted from a stationary diesel engine generator was treated with a hybrid system comprising NO(x) reduction by nonthermal plasma (NTP) and temperature swing adsorption (TSA) driven by engine waste heat. TSA produces a low-volume gas mixture of N(2) and highly concentrated NO(x), which is effectively reduced by NTP treatment. Improved treatment performance and efficiency are achieved by re-injecting the NTP-treated gas mixture into the engine intake. The system comprises two switchable adsorption chambers; the operation of this system was simulated by using a one-chamber system. The maximum energy efficiency for NO(x) treatment is 200 g(NO(2))/kWh. The respective contributions of NTP and injection of N(2) and NO(x) to the performance were theoretically analyzed. The analysis predicts that high energy efficiency and high NO(x)-removal efficiency can be simultaneously achieved with this system but miniaturization of the adsorption chambers will be a challenge. PMID:22771347

  16. 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…

  17. PSA discriminator influence on (222)Rn efficiency detection in waters by liquid scintillation counting.

    PubMed

    Stojković, Ivana; Todorović, Nataša; Nikolov, Jovana; Tenjović, Branislava

    2016-06-01

    A procedure for the (222)Rn determination in aqueous samples using liquid scintillation counting (LSC) was evaluated and optimized. Measurements were performed by ultra-low background spectrometer Quantulus 1220™ equipped with PSA (Pulse Shape Analysis) circuit which discriminates alpha/beta spectra. Since calibration procedure is carried out with (226)Ra standard, which has both alpha and beta progenies, it is clear that PSA discriminator has vital importance in order to provide precise spectra separation. Improvement of calibration procedure was done through investigation of PSA discriminator level and, consequentially, the activity of (226)Ra calibration standard influence on (222)Rn efficiency detection. Quench effects on generated spectra i.e. determination of radon efficiency detection were also investigated with quench calibration curve obtained. Radon determination in waters based on modified procedure according to the activity of (226)Ra standard used, dependent on PSA setup, was evaluated with prepared (226)Ra solution samples and drinking water samples with assessment of measurement uncertainty variation included. PMID:27016710

  18. A Microfluidic Love-Wave Biosensing Device for PSA Detection Based on an Aptamer Beacon Probe

    PubMed Central

    Zhang, Feng; Li, Shuangming; Cao, Kang; Wang, Pengjuan; Su, Yan; Zhu, Xinhua; Wan, Ying

    2015-01-01

    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. PMID:26110408

  19. 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

    2015-01-01

    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. PMID:26110408

  20. Overexpression and purification of folded domain of prostate cancer related proteins MSMB and PSA.

    PubMed

    Tiwary, Mohini; Agarwal, Nipanshu; Dinda, Amit; Yadav, Subhash C

    2016-05-01

    Overexpression of domains of a human protein using recombinant DNA technology has been challenging because individual domains intend to accumulate as non-soluble aggregate when expressed separately. Studies on identifying right sequences for a domain to be able to fold independently may help understand the folding pattern and underlying protein-engineering events to isolate the functional domains of a protein. In this report, individual domains of prostate cancer related biomarkers; MSMB and PSA were overexpressed in bacterial system and purified in their folded forms using affinity chromatography. The western blotting experiment using domain specific antibodies further confirmed these proteins. The designed nucleotide sequences domains were truncated using fold index software and folding were predicted by phyre2 and I-TASSER software. Other parameters were optimized for their overexpression and purification using Co-NTA affinity chromatography. Purified domains of each protein showed secondary structures such as α + β type for PSA, α/β and β type for the each domains of PSA and MSMB respectively. This is the first report on producing PSA and MSMB individual domains in functional folded forms. This study may help produce the folded domain of many such proteins to be used for better diagnostic purpose. PMID:27038170

  1. An evaluation of Pt sulfite acid (PSA) as precursor for supported Pt catalysts

    SciTech Connect

    Regalbuto, J.R.; Ansel, O.; Miller, J.T.

    2010-11-12

    As a catalyst precursor, platinum sulfite acid (PSA) is easy to use and not relatively expensive, and is a potentially attractive precursor for many types of supported catalysts. The ultimate usefulness for many catalyst applications will depend on the extent that Pt can be dispersed and sulfur eliminated. To our knowledge, there exists no detailed characterization in the catalysis literature of PSA and the nanoparticulate Pt phases derived from it during catalyst pretreatment. To this end a series of supports including alumina, silica, magnesia, niobia, titania, magnesia and carbon were contacted with PSA solutions and subsequently analyzed with extended x-ray absorption fine structure (EXAFS) and x-ray absorption near edge structure (XANES) analysis, and x-ray photoelectron spectroscopy (XPS) to characterize the Pt species formed upon impregnation, calcination, and reduction. While all catalysts show retention of some S, reasonably small particle sizes with relatively little Pt-S can in some instances be produced using PSA. The amount of retained sulfur appears to decrease with decreasing surface acidity, although even the most acidic supports (niobia and silica) display some storage of S even while only Pt-O bands are observed after calcination or reoxidation. More sulfur was eliminated by high temperature calcinations followed by reduction in hydrogen, at the expense of increasing Pt particle size.

  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. 3D label-free prostate specific antigen (PSA) immunosensor based on graphene-gold composites.

    PubMed

    Jang, Hee Dong; Kim, Sun Kyung; Chang, Hankwon; Choi, Jeong-Woo

    2015-01-15

    Highly sensitive and label-free detection of the prostate specific antigen (PSA) remains a challenge in the diagnosis of prostate cancer. Here, a novel three-dimensional (3D) electrochemical immunosensor capable of sensitive and label-free detection of PSA is reported. This unique immunosensor is equipped with a highly conductive graphene (GR)-based gold (Au) composite modified electrode. The GR-based Au composite is prepared using aerosol spray pyrolysis and the morphology of the composite is the shape of a crumpled GR ball decorated with Au nanoparticles. Unlike the previous research, this novel 3D immunosensor functions very well over a broad linear range of 0-10 ng/mL with a low detection limit of 0.59 ng/mL; furthermore, it exhibits a significantly increased electron transfer and high sensitivity toward PSA. The highest rate of current change with respect to the PSA concentration is 5 μA/(ng/mL). Satisfactory selectivity, reproducibility, and stability of the 3D immunosensor are also exhibited. PMID:25150936

  4. 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. |

  5. Total Order Reliability in PSA: Importance of Basic Events and Systems

    SciTech Connect

    E. Borgonovo; C. Smith

    2010-06-01

    The purpose of this work is twofold. First, to formalize the properties of the total order reliability importance measure for PSA models. Second, to extend the definition of the total order importance measure to groups of basic events. This allows one to obtain the importance of systems and to address the relevance of interactions among systems.

  6. 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. PMID:18973965

  7. 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. PMID:26573838

  8. Adsorption behavior of epirubicin hydrochloride on carboxylated carbon nanotubes.

    PubMed

    Chen, Zhe; Pierre, Dramou; He, Hua; Tan, Shuhua; Pham-Huy, Chuong; Hong, Hao; Huang, Jilong

    2011-02-28

    The aim of this study was to understand the interaction between carboxylated carbon nanotubes (c-CNTs) and anticancer agents and evaluate the drug-loading ability of c-CNTs. We prepared carboxylated multi-walled carbon nanotubes (c-MWNTs) with nitric acid treatment, then evaluated the adsorption ability of c-MWNTs as adsorbents for loading of the anticancer drug, epirubicin hydrochloride (EPI), and investigated the adsorption behavior of EPI on c-MWNTs. Unmodified multi-walled carbon nanotubes (MWNTs) and single-walled carbon nanotubes (SWNTs) were included as comparative adsorbents. The results showed that carbon nanotubes were able to form supramolecular complexes with EPI via π-π stacking and possessed favorable loading properties as drug carriers. The Freundilich adsorption model was successfully employed to describe the adsorption process. Because of the high surface area and hydrogen bonding, c-MWNTs' adsorption efficiency was the highest and the most stable and their drug-loading capacity was superior to that of MWNTs. With the increase of pH, the adsorption capacity of EPI on the c-MWNTs increased. Low-temperature facilitated the adsorption. More rapid EPI adsorption rate and higher drug-loading ability were observed from c-MWNTs with smaller diameter. Moreover, the adsorption kinetics of EPI on c-MWNTs could be well depicted by using the pseudo-second-order kinetic model. PMID:21145959

  9. 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)

  10. Adsorption behavior of heavy metals on biomaterials.

    PubMed

    Minamisawa, Mayumi; Minamisawa, Hiroaki; Yoshida, Shoichiro; Takai, Nobuharu

    2004-09-01

    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. PMID:15373400

  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. PMID:17937278

  12. Adsorption of tetrahydrothiophene (THT) onto soils

    NASA Astrophysics Data System (ADS)

    Juriga, Martin; Kubinec, Róbert; Rajzinger, Ján; Jelemenský, Karol; Gužela, Štefan

    2014-08-01

    Adsorption is one of the major industrial separation technique nowadays. Although adsorption is most commonly used as a separation method, in some cases cause harmful and undesirable effects such as capture odorant from natural gas onto soil. In the event of an accident, the gas can leak from pipes in two ways - either directly into the surrounding air, or the soil where the odorant can be mostly absorbed depending of type of soil, water content and temperature. Design of experimental apparatus for measurement of breakthrough curves is studied in detail. Alternative arrangement of experimental apparatus, calibration of measuring devices, method of measurement and processing the data are narrowly discussed. Moreover, experimental measurements of breakthrough curves are presented. The actual measurement was made to identify the equilibrium adsorption capacity of THT (tetrahydrothiophene) onto soils. Experimental data were evaluated using Linear, Freundlich, Langmuir and Koble-Corrigan model.

  13. Adsorption of Sr by immobilized microorganisms

    SciTech Connect

    Watson, J.S.; Scott, C.D.; Faison, B.D.

    1988-01-01

    Wastewaters from numerous industrial and laboratory operations can contain toxic or undesirable components such as metal ions, which must be removed before discharge to surface waters. Adsorption processes that have high removal efficiencies are attractive methods for removing such contaminants. For economic operations, it is desirable to have an adsorbent that is selective for the metal contaminant of interest, has high capacity for the contaminant, has rapid adsorption kinetics, can be economically produced, and can be regenerated to a concentrated waste product or decomposed to a low-volume waste. Selected microorganisms are potentially useful adsorbents for these applications because they can be inexpensive, have high selectivities, and have high capacities for adsorption of many heavy metals, which are often problems in a variety of industries. A laboratory-scale packed column containing microbial cells immobilized within a gelatin matrix has been prepared, and its application to removal of Sr from a simulated wastewater is described. 6 refs., 2 figs., 3 tabs.

  14. Prostate-specific Antigen (PSA) Density and Free to Total PSA Ratio in Diagnosing Prostate Cancer with Prostate-Specific Antigen Levels of 4.0 ng/ml or Less

    PubMed Central

    LIU, Xin; TANG, Jie; FEI, Xiang; LI, Qiu-Yang

    2015-01-01

    Background: We aimed to value the usefulness of free to total prostate-specific antigen and Prostate-specific antigen (PSA) density for prostate cancer in the patients with PSA levels of 4.0 ng/ml or less. Methods: A total of 343 subjects with PSA levels of 4.0 ng/ml or less were biopsied. All patients were divided into four groups according to the PSA levels: 0 to 1.0 ng/ml, 1.1 to 2.0 ng/ml, 2.1 to 3.0 ng/ml, and 3.1 to 4.0 ng/ml. The reliability of cancer detection in relation to the f/t PSA ratio and PSAD were estimated. Results: Overall, 65 people were diagnosed with prostate cancer. The detection rate was 16.28%、17.17%, 21.82%, 25.00% in subjects with PSA levels of 0 to 1.0 ng/ml, 1.1 to 2.0 ng/ml, 2.1 to 3.0 ng/ml, and 3.1 to 4.0 ng/ml, respectively. The f/t PSA ratio was significantly lower in patients with prostate cancer and PSA levels of 2.1 to 4.0 ng/ml (P<0.05). The PSAD had no statistical significance between the two groups. Conclusions: Routine prostate biopsy should be undertaken if the f/t PSA ratio less than 15% with /without abnormal DRE/TRUS findings. PMID:26744703

  15. 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. PMID:27191567

  16. 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.

  17. Adsorption of lead onto smectite from aqueous solution.

    PubMed

    Mhamdi, M; Galai, H; Mnasri, N; Elaloui, E; Trabelsi-Ayadi, M

    2013-03-01

    The purpose of this research is to study the effect of a new method of adsorption using membrane filtration to determine the maximum amount of lead adsorbed by clay and investigate the behavior of the clay after adsorption of the said metal. Treatment of wastewater contaminated with heavy metals depends on the characteristics of the effluent, the amount of final discharge, the cost of treatment, and the compatibility of the treatment process. The process of adsorption of heavy metals by clays may be a simple, selective, and economically viable alternative to the conventional physical-chemical treatment. This is justified by the importance of the surface developed by this material, the presence of negative charges on the said surface, the possibility of ion exchange taking place, and its wide availability in nature. The removal of lead from wastewater was studied by using the adsorption technique and using clay as the adsorbent. A method was optimized for adsorption through a membrane approaching natural adsorption. This new method is simple, selective, and the lead adsorption time is about 3 days. The various properties of clay were determined. It was observed that the cation exchange capacity of the clay was 56 meq/100 g of hydrated clay for the raw sample and 82 meq/100 g for the purified sample. The total surface area determined by the methylene blue method was equal to 556 and 783 m(2)/g for the raw and purified samples, respectively. The adsorption kinetics depends on several parameters. The Pb(II) clay, obeys the Langmuir, Freundlich, and the Elovich adsorption isotherms with high regression coefficients. The use of this adsorbent notably decreases the cost of treatment. It was concluded that clay shows a strong adsorption capacity on Pb(II), the maximum interaction occurring with purified clay treated at high concentration of lead. It is proposed that this adsorption through a membrane be extended for the treatment of effluents containing other metals. PMID

  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. PMID:16643942

  19. 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. PMID:12628781

  20. Adsorption of aniline and toluidines on montmorillonite

    SciTech Connect

    Essington, M.E. )

    1994-09-01

    Bentonite clay liners are commonly employed to mitigate the movement of contaminants from waste disposal sites. In order to assess the ability of clay liner material to restrict the mobility of amine compounds under a variety of chemical conditions and to further elucidate amine adsorption characteristics, the adsorption of aniline and o-, m-, and p-toluidine on Ca[sup 2+]- and K[sup +]-saturated Wyoming bentonite (SWy-1) was investigated. Adsorption experiments were performed under conditions of varied pH and ionic environment. Amine adsorption on montmorillonite is pH dependent. Maximum amine adsorption occurs when solution pH is approximately equal to the pK[sub a] of the anilinium ion deprotonation reaction (pH 4.45-5.08). An amine adsorption envelope results from the combined influence of increasing anilinium ion and anilinium-aniline complex formation (as pH decreases to the pK[sub a]) and amine competition with H[sup +] for surface sites, decreasing anilinium-aniline complex concentration, and decreasing aniline available for water bridging with exchangeable Ca[sup 2+] and K[sup +] (as solution pH decreases below the pK[sub a]). For any given amine, maximum adsorption increases with decreasing ionic strength. Maximum amine adsorption is greater in the Ca[sup 2+] systems than in the K[sup +] systems at equivalent cation charge and reflects the formation of an amine water bridge with the exchangeable Ca[sup 2+]. Amine adsorption is also greater in chloride systems compared with sulfate systems at comparable cation concentrations, possibly due to the formation of aqueous anilinium-sulfate complexes. The amine compounds are retained mainly by bentonite through a cation exchange process, the capacity of the clay to adsorb the amine compounds being a significant percentage of the exchange capacity at the pK[sub a]. However, amine retention decreases with increasing pH and is minimal at solution pH values greater than 7. 19 refs., 6 figs.

  1. HOXB13 overexpression is an independent predictor of early PSA recurrence in prostate cancer treated by radical prostatectomy

    PubMed Central

    Zabalza, Cristina Villares; Adam, Meike; Burdelski, Christoph; Wilczak, Waldemar; Wittmer, Corina; Kraft, Stefan; Krech, Till; Steurer, Stefan; Koop, Christina; Hube-Magg, Claudia; Graefen, Markus; Heinzer, Hans; Minner, Sarah; Simon, Ronald; Sauter, Guido; Schlomm, Thorsten; Tsourlakis, Maria Christina

    2015-01-01

    HOXB13 is a prostate cancer susceptibility gene which shows a cancer predisposing (G84E) mutation in 0.1–0.6% of males. We analyzed the prognostic impact of HOXB13 expression by immunohistochemistry on a tissue microarray containing more than 12,400 prostate cancers. Results were compared to tumor phenotype, biochemical recurrence, androgen receptor (AR) and prostate specific antigen (PSA) as well as molecular subtypes defined by ERG status and genomic deletions of 3p, 5q, 6q, and PTEN. HOXB13 immunostaining was detectable in 51.7% of 10,216 interpretable cancers and considered strong in 9.6%, moderate in 19.7% and weak in 22.3% of cases. HOXB13 expression was linked to advanced pT stage, high Gleason grade, positive lymph node status (p < 0.0001 each), high pre-operative PSA levels (p = 0.01), TMPRSS2:ERG fusion, PTEN deletions, AR expression, cell proliferation, reduced PSA expression and early PSA recurrence (p < 0.0001 each). The prognostic value of HOXB13 was independent from established parameters including Gleason, stage, nodal stage and PSA. Co-expression analysis identified a subset of tumors with high HOXB13 and AR but low PSA expression that had a particularly poor prognosis. HOXB13 appears to be a promising candidate for clinical routine tests either alone or in combination with other markers, including AR and PSA. PMID:25825985

  2. Adsorption dynamics of methyl violet onto granulated mesoporous carbon: Facile synthesis and adsorption kinetics.

    PubMed

    Kim, Yohan; Bae, Jiyeol; Park, Hosik; Suh, Jeong-Kwon; You, Young-Woo; Choi, Heechul

    2016-09-15

    A new and facile one-step synthesis method for preparing granulated mesoporous carbon (GMC) with three-dimensional spherical mesoporous symmetry is prepared to remove large molecular weight organic compounds in aqueous phase. GMC is synthesized in a single step using as-synthesized mesoporous carbon particles and organic binders through a simple and economical synthesis approach involving a simultaneous calcination and carbonization process. Characterization results obtained from SEM, XRD, as well as surface and porosity analysis indicate that the synthesized GMC has similar physical properties to those of the powdered mesoporous carbon and maintains the Brunauer-Emmett-Teller (BET) surface area and pore volume because the new synthesis method prevents the collapse of the pores during the granulation process. Batch adsorption experiments revealed GMC showed a substantial adsorption capacity (202.8 mg/g) for the removal of methyl violet as a target large molecular contaminant in aqueous phase. The mechanisms and dynamics modeling of GMC adsorption were also fully examined, which revealed that surface diffusion was rate limiting step on adsorption process of GMC. Adsorption kinetics of GMC enables 3 times faster than that of granular activated carbon in terms of surface diffusion coefficient. This is the first study, to the best of our knowledge, to synthesize GMC as an adsorbent for water purification by using facile granulation method and to investigate the adsorption kinetics and characteristics of GMC. This study introduces a new and simple method for the synthesis of GMC and reveals its adsorption characteristics for large molecular compounds in a water treatment. PMID:27262123

  3. Adsorption of a multicomponent rhamnolipid surfactant to soil

    SciTech Connect

    Noordmann, W.H.; Brusseau, M.L.; Janssen, D.B.

    2000-03-01

    The adsorption of rhamnolipid, a multicomponent biosurfactant with potential application in soil remediation, to two sandy soils was investigated using batch and column studies. The surfactant mixture contained six anionic components differing in lipid chain length and number of rhamnose moieties. Batch adsorption experiments indicated that the overall adsorption isotherms of total surfactant and of the individual components leveled off above a concentration at which micelles were formed. Column experiments showed that the retardation factors for the total surfactant and for the individual components decreased with increasing influent concentration. Extended tailing was observed in the distal portion of the surfactant breakthrough curve. The concentration-dependent retardation factors and the extended tailing are in accordance with the nonlinear (concave) adsorption isotherms found in the batch adsorption studies. The more hydrophobic rhamnolipid components were preferentially adsorbed, but adsorption was not correlated with the organic carbon content of the soil. This suggests that adsorption of rhamnolipid to soil is not a partitioning process but mainly an interfacial adsorption process.

  4. 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

  5. Fundamentals of high pressure adsorption

    SciTech Connect

    Zhou, Y.P.; Zhou, L.

    2009-12-15

    High-pressure adsorption attracts research interests following the world's attention to alternative fuels, and it exerts essential effect on the study of hydrogen/methane storage and the development of novel materials addressing to the storage. However, theoretical puzzles in high-pressure adsorption hindered the progress of application studies. Therefore, the present paper addresses the major theoretical problems that challenged researchers: i.e., how to model the isotherms with maximum observed in high-pressure adsorption; what is the adsorption mechanism at high pressures; how do we determine the quantity of absolute adsorption based on experimental data. Ideology and methods to tackle these problems are elucidated, which lead to new insights into the nature of high-pressure adsorption and progress in application studies, for example, in modeling multicomponent adsorption, hydrogen storage, natural gas storage, and coalbed methane enrichment, was achieved.

  6. Continuous water treatment by adsorption and electrochemical regeneration.

    PubMed

    Mohammed, F M; Roberts, E P L; Hill, A; Campen, A K; Brown, N W

    2011-05-01

    This study describes a process for water treatment by continuous adsorption and electrochemical regeneration using an air-lift reactor. The process is based on the adsorption of dissolved organic pollutants onto an adsorbent material (a graphite intercalation compound, Nyex(®)1000) and subsequent electrochemical regeneration of the adsorbent leading to oxidation of the adsorbed pollutant. Batch experiments were carried out to determine the adsorption kinetics and equilibrium isotherm for adsorption of a sample contaminant, the organic dye Acid Violet 17. The adsorbent circulation rate, the residence time distribution (RTD) of the reactor, and treatment by continuous adsorption and electrochemical regeneration were studied to investigate the process performance. The RTD behaviour could be approximated as a continuously stirred tank. It was found that greater than 98% removal could be achieved for continuous treatment by adsorption and electrochemical regeneration for feed concentrations of up to 300 mg L(-1). A steady state model has been developed for the process performance, assuming full regeneration of the adsorbent in the electrochemical cell. Experimental data and modelled predictions (using parameters for the adsorbent circulation rate, adsorption kinetics and isotherm obtained experimentally) of the dye removal achieved were found to be in good agreement. PMID:21511325

  7. Adsorption--from theory to practice.

    PubMed

    Dabrowski, A

    2001-10-01

    Adsorption at various interfaces has concerned scientists since the beginning of this century. This phenomenon underlies a number of extremely important processes of utilitarian significance. The technological, environmental and biological importance of adsorption can never be in doubt. Its practical applications in industry and environmental protection are of paramount importance. The adsorption of substrates is the first stage in many catalytic processes. The methods for separation of mixtures on a laboratory and on an industrial scale are increasingly based on utilising the change in concentration of components at the interface. Moreover, such vital problems as purification of water, sewages, air and soil are involved here too. On the other hand, many areas in which technological innovation has covered adsorption phenomena have been expanded more through art and craft than through science. A basic understanding of the scientific principles is far behind; in part because the study of interfaces requires extremely careful experimentation if meaningful and reproducible results are to be obtained. In recent years, however, considerable effort has been increasingly directed toward closing the gap between theory and practice. Crucial progress in theoretical description of the adsorption has been achieved, mainly through the development of new theoretical approaches formulated on a molecular level, by means of computer simulation methods and owing to new techniques which examine surface layers or interfacial regions. Moreover, during the last 15 years new classes of solid adsorbents have been developed, such as activated carbon fibres and carbon molecular sieves, fullerenes and heterofullerenes, microporous glasses and nanoporous--both carbonaceous and inorganic--materials. Nanostructured solids are very popular in science and technology and have gained extreme interest due to their sorption, catalytic, magnetic, optical and thermal properties. Although the development

  8. Extracorporeal adsorption of endotoxin.

    PubMed

    Staubach, K H; Rosenfeldt, J A; Veit, O; Bruch, H P

    1997-02-01

    In a porcine endotoxin shock model using a continuous intravenous endotoxin infusion of 250 ng/kg body weight per hour, the cardiorespiratory and hematologic parameters were studied while applying a new on-line polymyxin B immobilized adsorption system. This preliminary report shows that the new adsorbent can remove endotoxin selectively from the circulation and confers a good amount of protection from endotoxin-induced cardiopulmonary decompensation as well as hematologic alterations. Survival time could be extended from 216 min to 313 min. Whereas cardiac output and mean arterial pressure declined critically after 3 h in the controls, the treated group remained stable for another 3 h. These data show that endotoxin adsorption by polymyxin B coupled covalently to acrylic spheres as an adjunctive on-line measure in the septic syndrome seems feasible. PMID:10225785

  9. 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

  10. Regenerable adsorption system

    NASA Technical Reports Server (NTRS)

    Roychoudhury, Subir (Inventor); Perry, Jay (Inventor); Walsh, Dennis (Inventor)

    2006-01-01

    A method for regenerable adsorption includes providing a substrate that defines at least one layer of ultra short channel length mesh capable of conducting an electrical current therethrough, coating at least a portion of the substrate with a desired sorbent for trace contaminant control or CO.sub.2 sorption, resistively heating the substrate, and passing a flowstream through the substrate and in contact with the sorbent.

  11. Adsorption of amino acids and glucose by sediments of Resurrection Bay, Alaska, USA: Functional group effects

    NASA Astrophysics Data System (ADS)

    Henrichs, Susan M.; Sugai, Susan F.

    1993-02-01

    The adsorption of amino acids and glucose was investigated in sediments from Resurrection Bay, Alaska. Adsorption of the basic amino acid lysine was greater than adsorption of glutamic acid, alanine, leucine, or glucose. Formaldehyde and heat treatments were used to separate adsorption from biological uptake, but can alter adsorption significantly; formaldehyde treatment, followed by a seawater rinse, was the most satisfactory. Much of the rapid amino acid adsorption by these sediments was due to the formation of ionic bonds, since adsorbed amino acids could be extracted using concentrated solutions of amino acid, cesium chloride, sodium citrate, ammonium chloride, or sodium acetate. However, most amino acid adsorption was not reversible by ion exchange solutions, indicating that additional processes or chemical reactions occur which result in irreversible binding to sediment. Consistent with literature reports of the negative surface charge of marine particulate matter, lysine (with a net positive charge) was adsorbed to the greatest extent and had the largest cation-exchangeable adsorption. However, negatively charged amino acid functional groups also influenced adsorption. Chemical modification of sediments with reagents reactive with aldehydes decreased lysine adsorption. This suggests that reactive functional groups of sediment organic matter contribute to adsorption, consistent with a melanoidintype reaction. An estimate of the rate of amino acid adsorption indicates that adsorption could produce a significant amount of the total refractory sediment organic nitrogen.

  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. The adsorption of HCl on volcanic ash

    NASA Astrophysics Data System (ADS)

    Gutiérrez, Xochilt; Schiavi, Federica; Keppler, Hans

    2016-03-01

    Understanding the interaction between volcanic gases and ash is important to derive gas compositions from ash leachates and to constrain the environmental impact of eruptions. Volcanic HCl could potentially damage the ozone layer, but it is unclear what fraction of HCl actually reaches the stratosphere. The adsorption of HCl on volcanic ash was therefore studied from -76 to +150 °C to simulate the behavior of HCl in the dilute parts of a volcanic plume. Finely ground synthetic glasses of andesitic, dacitic, and rhyolitic composition as well as a natural obsidian from Vulcano (Italy) served as proxies for fresh natural ash. HCl adsorption is an irreversible process and appears to increase with the total alkali content of the glass. Adsorption kinetics follow a first order law with rate constants of 2.13 ṡ10-6 s-1 to 1.80 ṡ10-4 s-1 in the temperature range investigated. For dacitic composition, the temperature and pressure dependence of adsorption can be described by the equation ln ⁡ c = 1.26 + 0.27 ln ⁡ p - 715.3 / T, where c is the surface concentration of adsorbed HCl in mg/m2, T is temperature in Kelvin, and p is the partial pressure of HCl in mbar. A comparison of this model with a large data set for the composition of volcanic ash suggests that adsorption of HCl from the gas phase at relatively low temperatures can quantitatively account for the majority of the observed Cl concentrations. The model implies that adsorption of HCl on ash increases with temperature, probably because of the increasing number of accessible adsorption sites. This temperature dependence is opposite to that observed for SO2, so that HCl and SO2 are fractionated by the adsorption process and the fractionation factor changes by four orders of magnitude over a temperature range of 250 K. The assumption of equal adsorption of different species is therefore not appropriate for deriving volcanic gas compositions from analyses of adsorbates on ash. However, with the experimental

  15. Kinetic aspects of the adsorption of xyloglucan onto cellulose nanocrystals.

    PubMed

    Villares, Ana; Moreau, Céline; Dammak, Abir; Capron, Isabelle; Cathala, Bernard

    2015-08-28

    In this work, the adsorption of a neutral flexible polysaccharide, xyloglucan (XG), onto thin cellulose nanocrystal (CNC) surfaces has been investigated to get more insight into the CNC-XG association. Gold-coated quartz crystals were spin-coated with one layer of CNC, and XG adsorption was monitored in situ using a quartz crystal microbalance with dissipation (QCM-D). The adsorption of XG under flow at different concentrations did not result in the same surface concentration, which evidenced a kinetically controlled process. In an attempt to describe the binding of XG to CNCs, adsorption data were fitted to a kinetic model comprising a contribution from XG adsorption onto uncovered CNC surfaces and a contribution from XG adsorption after rearrangement. Kinetic studies evidenced the presence of two adsorption regimes as a function of XG concentration. For low XG concentrations, the kinetic constant for chain rearrangement is comparable to the kinetic constant for adsorption. This fact implies a rearrangement and alignment of XG molecules on CNCs. Differently, for higher XG concentrations, the kinetic constant related to the conformational rearrangement decreases, indicating that XG molecules have no time to laterally rearrange before new XG molecules adsorb. PMID:26179417

  16. 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. PMID:19202872

  17. 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.

  18. Adsorption of CO Molecules on Si(001) at Room Temperature

    NASA Astrophysics Data System (ADS)

    Seo, Eonmi; Eom, Daejin; Kim, Hanchul; Koo, Ja-Yong

    2015-03-01

    Initial adsorption of CO molecules on Si(001) is investigated by using room-temperature (RT) scanning tunneling microscopy (STM) and density functional theory calculations. Theoretical calculations show that only one adsorption configuration of terminal-bond CO (T-CO) is stable and that the bridge-bond CO is unstable. All the abundantly observed STM features due to CO adsorption can be identified as differently configured T-COs. The initial sticking probability of CO molecules on Si(001) at RT is estimated to be as small as ~ 1 x 10-4 monolayer/Langmuir, which is significantly increased at high-temperature adsorption experiments implying a finite activation barrier for adsorption. Thermal annealing at 900 K for 5 min results in the dissociation of the adsorbed CO molecules with the probability of 60-70% instead of desorption, indicating both a strong chemisorption state and an activated dissociation process. The unique adsorption state with a large binding energy, a tiny sticking probability, and a finite adsorption barrier is in stark contrast with the previous low-temperature (below 100 K) observations of a weak binding, a high sticking probability, and a barrierless adsorption. We speculate that the low-temperature results might be a signature of a physisorption state in the condensed phase.

  19. Cysteine-rich secretory protein 3 plays a role in prostate cancer cell invasion and affects expression of PSA and ANXA1.

    PubMed

    Pathak, Bhakti R; Breed, Ananya A; Apte, Snehal; Acharya, Kshitish; Mahale, Smita D

    2016-01-01

    Cysteine-rich secretory protein 3 (CRISP-3) is upregulated in prostate cancer as compared to the normal prostate tissue. Higher expression of CRISP-3 has been linked to poor prognosis and hence it has been thought to act as a prognostic marker for prostate cancer. It is proposed to have a role in innate immunity but its role in prostate cancer is still unknown. In order to understand its function, its expression was stably knocked down in LNCaP cells. CRISP-3 knockdown did not affect cell viability but resulted in reduced invasiveness. Global gene expression changes upon CRISP-3 knockdown were identified by microarray analysis. Microarray data were quantitatively validated by evaluating the expression of seven candidate genes in three independent stable clones. Functional annotation of the differentially expressed genes identified cell adhesion, cell motility, and ion transport to be affected among other biological processes. Prostate-specific antigen (PSA, also known as Kallikrein 3) was the top most downregulated gene whose expression was also validated at protein level. Interestingly, expression of Annexin A1 (ANXA1), a known anti-inflammatory protein, was upregulated upon CRISP-3 knockdown. Re-introduction of CRISP-3 into the knockdown clone reversed the effect on invasiveness and also led to increased PSA expression. These results suggest that overexpression of CRISP-3 in prostate tumor may maintain higher PSA expression and lower ANXA1 expression. Our data also indicate that poor prognosis associated with higher CRISP-3 expression could be due to its role in cell invasion. PMID:26369530

  20. [Adsorption of Cr (VI) on magnetic graphene from aqueous solution].

    PubMed

    Liu, Wei; Yang, Qi; Li, Bo; Chen, Hai; Nie, Lan-Yu

    2015-02-01

    Chemical deposition method was applied to prepare magnetic graphene composites using graphite oxide and ferric salt (FeCl2 - 4H2O and FeCl3 x 6H2O) as starting materials. The static experiments were performed to study kinetics, thermodynamic, adsorption isotherm and effects of various parameters, such as pH, temperature and time on Cr(VI) adsorption. The results showed that adsorption kinetics followed the pseudo-second-order model. Compared with Freundlich isotherm, Langmuir isotherm could better describe the adsorption process. The parameters of thermodynamics were ΔHθ = 33.89 kJ x mol(-1), ΔSθ = 120.15 J x (mol x K)(-1), ΔGθ = -2.51 kJ x mol(-1) (303 K), it demonstrated that the adsorption was a spontaneously endothermic process. It also indicated that the optimal pH was 2. Higher temperature and extension of time were in favor of adsorption. When used repeatedly for three times, the adsorption capacity decreased from 3.9 mg x g(-1) to 2.1 mg x g(-1) with an initial concentration of 5 mg x L(-1). By using a permanent magnet, the recycling process of adsorbent was easy to be operated and adsorbent could be regenerated by sodium hydrate solution. Hence, the composites is a promising adsorbent for efficient removal of Cr(VI) from wastewater. PMID:26031080

  1. Isotherms for Water Adsorption on Molecular Sieve 3A: Influence of Cation Composition

    DOE PAGESBeta

    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 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

  2. 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.

  3. Adsorption and regenerative oxidation of trichlorophenol with synthetic zeolite: Ozone dosage and its influence on adsorption performance.

    PubMed

    Zhang, Yongjun; Prigent, Bastien; Geißen, Sven-Uwe

    2016-07-01

    Regeneration of loaded adsorbents is a key step for the sustainability of an adsorption process. In this study, ozone was applied to regenerate a synthetic zeolite for the adsorption of trichlorophenol (TCP) as an organic model pollutant. Three initial concentrations of TCP in water phase were used in adsorption tests. After the equilibrium, zeolite loaded different amounts of TCP was dried and then regenerated with ozone gas. It was found that the adsorption capacity of zeolite was increased through three regeneration cycles. However, the adsorption kinetics was compromised after the regeneration with slightly declined 2nd order reaction constants. The ozone demand for the regeneration was highly dependent on the TCP mass loaded onto the zeolite. It was estimated that the mass ratio of ozone to TCP was 1.2 ± 0.3 g O3/g TCP. PMID:27043379

  4. Preparation and properties of UV curable acrylic PSA by vinyl bonded graphene oxide

    NASA Astrophysics Data System (ADS)

    Pang, Beili; Ryu, Chong-Min; Jin, Xin; Kim, Hyung-Il

    2013-11-01

    Acrylic pressure sensitive adhesives (PSAs) with higher thermal stability for thin wafer handling were successfully prepared by forming composite with the graphene oxide (GO) nanoparticles modified to have vinyl groups via subsequent reaction with isophorone diisocyanate and 2-hydroxyethyl methacrylate. The acrylic copolymer was synthesized as a base resin for PSAs by solution radical polymerization of ethyl acrylate, 2-ethylhexyl acrylate, and acrylic acid followed by further modification with GMA to have the vinyl groups available for UV curing. The peel strength of PSA decreased with the increase of gel content which was dependent on both modified GO content and UV dose. Thermal stability of UV-cured PSA was improved noticeably with increasing the modified GO content mainly due to the strong and extensive interfacial bonding formed between the acrylic copolymer matrix and GO fillers

  5. Predictive simulations and optimization of nanowire field-effect PSA sensors including screening

    NASA Astrophysics Data System (ADS)

    Baumgartner, Stefan; Heitzinger, Clemens; Vacic, Aleksandar; Reed, Mark A.

    2013-06-01

    We apply our self-consistent PDE model for the electrical response of field-effect sensors to the 3D simulation of nanowire PSA (prostate-specific antigen) sensors. The charge concentration in the biofunctionalized boundary layer at the semiconductor-electrolyte interface is calculated using the propka algorithm, and the screening of the biomolecules by the free ions in the liquid is modeled by a sensitivity factor. This comprehensive approach yields excellent agreement with experimental current-voltage characteristics without any fitting parameters. Having verified the numerical model in this manner, we study the sensitivity of nanowire PSA sensors by changing device parameters, making it possible to optimize the devices and revealing the attributes of the optimal field-effect sensor.

  6. A Simple PSA-Based Computational Approach Predicts the Timing of Cancer Relapse in Prostatectomized Patients.

    PubMed

    Stura, Ilaria; Gabriele, Domenico; Guiot, Caterina

    2016-09-01

    Recurrences of prostate cancer affect approximately one quarter of patients who have undergone radical prostatectomy. Reliable factors to predict time to relapse in specific individuals are lacking. Here, we present a mathematical model that evaluates a biologically sensible parameter (α) that can be estimated by the available follow-up data, in particular by the PSA series. This parameter is robust and highly predictive for the time to relapse, also after administration of adjuvant androgen deprivation therapies. We present a practical computational method based on the collection of only four postsurgical PSA values. This study offers a simple tool to predict prostate cancer relapse. Cancer Res; 76(17); 4941-7. ©2016 AACR. PMID:27587651

  7. 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. PMID:26364228

  8. Assessing the adsorption properties of shales

    NASA Astrophysics Data System (ADS)

    Pini, Ronny

    2015-04-01

    Physical adsorption refers to the trapping of fluid molecules at near liquid-like densities in the pores of a given adsorbent material. Fine-grained rocks, such as shales, contain a significant amount of nanopores that can significantly contribute to their storage capacity. As a matter of fact, 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 (either natural or stimulated), thus leading to recovery efficiencies that are very low. Shales constitute also a great portion of so-called cap-rocks above potential CO2 sequestration sites; hereby, the adsorption process may limit the CO2 mobility within the cap-rock, thus minimizing the impact of leakage on the whole operation. Whether it is an unconventional reservoir or a cap-rock, 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 (a major component in mudrocks) 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 in heterogeneous materials. The data are analyzed by using thermodynamically rigorous measures of adsorption, such as the net- and excess adsorbed amounts and a recently developed methodology is

  9. [PSA bounce phenomenon after local treatment with radiation for prostate cancer].

    PubMed

    Rodríguez, M A Cabeza; Escutia, M A Pérez; Antolín, A Rodríguez; Costoso, N Gascón; García, A Cascales; González, E Lanzós

    2012-01-01

    Radiotherapy is a curative treatment for localized prostate cancer in its modalities of brachytherapy (BT) and external beam radiotherapy (EBRT). A temporary increase in prostate-specific antigen (PSA) values following a radiotherapy treatment coupled with a decrease without therapeutic intervention may happen in 30% of the patients. This phenomenon is known as PSA bounce and lacks prognostic effect in relation to tumor control. Additionally, it produces anxiety in the patient because of the fear of failure, and in the physicists due to the uncertainty about the state of the tumor. The etiology and pathogenesis are still unknown. Several factors associated with the tumor and the treatments have been evaluated in the studies which analyze this phenomenon, the age is the only observed factor with the highest consistency as a bounce predictor. The definition of biologic failure (BF)after EBRT or BT with or without androgenic deprivation (ADT) according to Phoenix criteria, which considers an increase of at least 2 ng/ml over PSA nadir, enables better taking the bounce phenomenon into account, although is not free from false BF that may affect to the relapse-free survival in patients with follow-up shorter than 3 years. PMID:22318175

  10. Recombinant Forms of Leishmania amazonensis Excreted/Secreted Promastigote Surface Antigen (PSA) Induce Protective Immune Responses in Dogs.

    PubMed

    Petitdidier, Elodie; Pagniez, Julie; Papierok, Gérard; Vincendeau, Philippe; Lemesre, Jean-Loup; Bras-Gonçalves, Rachel

    2016-05-01

    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

  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. Expression of PCA3 and PSA genes as a biomarker for differential diagnosis of nodular hyperplasia and prostate cancer.

    PubMed

    Coelho, F Fonseca; Guimarães, F Loli; Cabral, W L Ribeiro; Salles, P G Oliveira; Mateo, E Cueva; Nogueira e Nogueira, L Mendes; Fonseca, C E Corradi; Gomes, K Braga

    2015-01-01

    We evaluated the expression of the PCA3 gene in urine from patients with nodular hyperplasia/benign prostatic hyperplasia (PNH) or adenocarcinoma type prostate cancer (PCa).The study included 59 men: 22 with PCa, 26 with PNH, and 11 with no alterations (controls). Patients' urine was collected following prostatic massage and quantified by quantitative real-time PCR for prostate cancer antigen 3 gene (PCA3) and prostate-specific antigen gene (PSA) expression with the ACTB gene for normalization. PCA3 gene expression was detected in 16 patients with PCa and 4 with PNH; in the control group, there was no expression of the gene. No significant difference was observed in the mean levels of PCA3 and PSA expression, the PCA3/PSA ratio, and the total PSA levels when the groups of patients with PCa and PNH were compared. The area under the receiver operating characteristic (ROC) curve was 0.625, 0.596, 0.559, and 0.503 for PCA3 and PSA expression, the PCA3/PSA ratio, and total PSA levels, respectively. The sensitivity and specificity of the PCA3 test were 73 and 85%, respectively. Considering the estimated cutoff values (0.2219 and 0.5007 for PCA3 and PCA3/PSA, respectively), we observed a significant difference between the frequency of individuals with values above in the PCa group compared with the PNH group (P < 0.001). We conclude that the qualitative PCA3 test could be applied to initial screening for differentiation between individuals with PCa or PNH and those without prostate changes. PMID:26535666

  13. Adsorption and decolorization kinetics of methyl orange by anaerobic sludge.

    PubMed

    Yu, Lei; Li, Wen-Wei; Lam, Michael Hon-Wah; Yu, Han-Qing

    2011-05-01

    Adsorption and decolorization kinetics of methyl orange (MO) by anaerobic sludge in anaerobic sequencing batch reactors were investigated. The anaerobic sludge was found to have a saturated adsorption capacity of 36 ± 1 mg g MLSS(-1) to MO. UV/visible spectrophotometer and high-performance liquid chromatography analytical results indicated that the MO adsorption and decolorization occurred simultaneously in this system. This process at various substrate concentrations could be well simulated using a modified two-stage model with apparent pseudo first-order kinetics. Furthermore, a noncompetitive inhibition kinetic model was also developed to describe the MO decolorization process at high NaCl concentrations, and an inhibition constant of 3.67 g NaCl l(-1) was estimated. This study offers an insight into the adsorption and decolorization processes of azo dyes by anaerobic sludge and provides a better understanding of the anaerobic dye decolorization mechanisms. PMID:21279343

  14. Evaluation of the adsorption capacity of alkali-treated waste materials for the adsorption of sulphamethoxazole.

    PubMed

    Kurup, Lisha

    2012-01-01

    The present work is to develop potential adsorbents from waste material and employ them for the removal of a hazardous antibacterial, sulphamethoxazole, from the wastewater by the Adsorption technique. The Adsorption technique was used to impound the dangerous antibiotics from wastewater using Deoiled Soya (DOS), an agricultural waste, and Water Hyacinth (WH), a prolific colonizer. The adsorption capacity of these adsorbents was further enhanced by treating them with sodium hydroxide solution and it was seen that the adsorption capacity increases by 10 to 25%. Hence a comparative account of the adsorption studies of all the four adsorbents, i.e. DOS, Alkali-treated DOS, WH and Alkali-treated Water Hyacinth has been discussed in this paper. Different isotherms like Freundlich, Langmuir and Dubinin-Radushkevich were also deduced from the adsorption data. Isotherm studies were in turn used in estimating the thermodynamic parameters. DOS showed sorption capacity of 0.0007 mol g(-1) while Alkali-treated Deoiled Soya exhibited 0.0011 mol g(-1) of sorption capacity, which reveals that the adsorption is higher in case of alkali-treated adsorbent. The mean sorption energy (E) was obtained between 9 and 12 kJ mol, which shows that the reaction proceeds by ion exchange reaction. Kinetic study reveals that the reaction follows pseudo-second-order rate equation. Moreover, mass transfer studies performed for the ongoing processes show that the mass transfer coefficient obtained for alkali-treated moieties was higher than the parent moieties. The breakthrough curves plotted from the column studies show percentage saturation of 90-98%. About 87-97% of sulphamethoxazole was recovered from column by desorption. PMID:22508113

  15. Adsorption and solid catalysed reaction between activated carbon impregnated with SnO 2 and CO at ordinary temperature

    NASA Astrophysics Data System (ADS)

    Iyuke, Sunny E.; Ahmadun, Fakhru'l.-Razi

    2002-02-01

    We have used pressure swing adsorption (PSA) measurements to study the reaction of CO adsorbed from H 2/CO (75/25 vol.%) onto an activated carbon-tin(IV) oxide (AC-SnO 2) catalyst to form gaseous CO 2. Unimpregnated pure activated carbon was used for comparison. Our data fit well to Langmuir-Hinshelwood kinetics with a rate constant of 0.022 s -1 and an equilibrium constant of 1.04, indicating first-order kinetics. We conclude that chemisorption takes place preferentially on the adsorbed O - sites produced during the thermal pre-treatment of the catalyst.

  16. Protein adsorption on piezoelectric poly(L-lactic) acid thin films by scanning probe microscopy

    NASA Astrophysics Data System (ADS)

    Barroca, Nathalie; Vilarinho, Paula M.; Daniel-da-Silva, Ana Luisa; Wu, Aiying; Fernandes, Maria Helena; Gruverman, Alexei

    2011-03-01

    Up until now, no direct evidence of protein adsorption processes associated with polar activity of a piezoelectric has been reported. This work presents the experimental evidence of the protein adsorption process' dependence on the surface polarization of a piezoelectric by showing at the local scale that the process of protein adsorption is highly favored in the poled areas of a piezoelectric polymer such as poly(L-lactic) acid.

  17. Effects of PSA Removal from NCAM on the Critical Period Plasticity Triggered by the Antidepressant Fluoxetine in the Visual Cortex.

    PubMed

    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. Patterns of Clinical Response to PSA Elevation in American Indian/Alaska Native Men: A Multi-center Pilot Study

    PubMed Central

    Tilburt, Jon C.; Koller, Kathryn; Tiesinga, James J.; Wilson, Robin T.; Trinh, Anne C.; Hill, Kristin; Hall, Ingrid J.; Smith, Judith Lee; Ekwueme, Donatus U.; Petersen, Wesley O.

    2016-01-01

    Objective To assess clinical treatment patterns and response times among American Indian/Alaska Native men with a newly elevated PSA. Methods We retrospectively identified men ages 50–80 receiving care in one of three tribally-operated clinics in Northern Minnesota, one medical center in Alaska, and who had an incident PSA elevation (≥ 4 ng/ml) in a specified time period. A clinical response was considered timely if it was documented as occurring within 90 days of the incident PSA elevation. Results Among 82 AI/AN men identified from medical records with an incident PSA elevation, 49 (60%) received a timely clinical response, while 18 (22%) had no documented clinical response. Conclusions One in five AI/AN men in our study had no documented clinical action following an incident PSA elevation. Although a pilot study, these findings suggest the need to improve the documentation, notification, and care following an elevated PSA at clinics serving AI/AN men. PMID:24185163

  19. 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

    2015-01-01

    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. PMID:25360665

  20. 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

  1. Adsorption Model for Off-Gas Separation

    SciTech Connect

    Veronica J. Rutledge

    2011-03-01

    The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior and feedback loops. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes will provide substantial cost savings and many technical benefits. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed in gPROMS software. Inputs include gas stream constituents, sorbent, and column properties, equilibrium and kinetic data, and inlet conditions. It models dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions for a multiple component gas stream. The simulation outputs component concentrations along the column length as a function of time from which the breakthrough data is obtained. It also outputs temperature along the column length as a function of time and pressure drop along the column length. Experimental data will be input into the adsorption model to develop a model specific for iodine adsorption on silver mordenite as well as model(s) specific for krypton and xenon adsorption. The model will be validated with experimental breakthrough curves. Another future off-gas modeling goal is to develop a model for the unit operation absorption. The off-gas models will be made available via the server or web for evaluation by customers.

  2. Adsorption kinetics and thermodynamics of acid Bordeaux B from aqueous solution by graphene oxide/PAMAMs.

    PubMed

    Zhang, Fan; He, Shengfu; Zhang, Chen; Peng, Zhiyuan

    2015-01-01

    Graphene oxide/polyamidoamines dendrimers (GO/PAMAMs) composites were synthesized via modifying GO with 2.0 G PAMAM. The adsorption behavior of the GO/PAMAMs for acid Bordeaux B (ABB) was studied and the effects of media pH, adsorption time and initial ABB concentration on adsorption capacity of the adsorbent were investigated. The optimum pH value of the adsorption of ABB onto GO/PAMAMs was 2.5. The maximum adsorption capacity increased from 325.78 to 520.83 mg/g with the increase in temperature from 298 to 328 K. The equilibrium data followed the Langmuir isotherm model better than the Freundlich model. The kinetic study illustrated that the adsorption of ABB onto GO/PAMAMs fit the pseudo-second-order model. The thermodynamic parameters indicated that the adsorption process was physisorption, and also an endothermic and spontaneous process. PMID:26398038

  3. Adsorption of diblock polypeptides on polystyrene latex.

    PubMed

    Jain, Ritesh; Forciniti, Daniel

    2012-10-30

    The adsorption of peptides at solid/liquid interfaces is affected by peptide/surface and peptide/peptide hydrophobic and electrostatic forces. Three diblock copolypeptides and two homopeptides were adsorbed on poly(styrene) nanospheres from water, water/methanol, and water/glycerol mixtures at different pH's to study both of these effects. Peptides with one hydrophilic (glutamic acid or lysine) and one nonpolar block (alanine) or with both hydrophilic blocks with opposite charges (glutamic acid and lysine) were chemically synthesized and used as adsorbates in this study. The amount adsorbed was determined, and dynamic light scattering (DLS) was used to measure the adsorbed layer thickness. It was found that peptide/surface and peptide/peptide electrostatic interactions dominate the adsorption process. Hydrophobic forces also play a role, but secondary to electrostatic forces. Positively charged blocks show high affinity for the surface, whereas negatively charged blocks were excluded from it. Poly(Lys) has the highest affinity by the surface, while (Glu)(14)-b-(Ala)(5) has the lowest. Adsorption of all peptides was inhibited by methanol and promoted by glycerol. The adsorption for (Lys)(5)-b-(Glu)(6) was extremely sensitive to pH, irrespective of cosolvent, whereas the thickness for (Lys)(30)-b-(Ala)(41) was sensitive to pH as well as cosolvent. Aggregation was observed in the presence of the nanosurfaces but not in the bulk peptides under some pH and solvent conditions. PMID:23009064

  4. Adsorption of hexavalent chromium on dunite.

    PubMed

    Demetriou, Antri; Pashalidis, Ioannis

    2011-01-01

    The paper presents and discusses the effect of various physicochemical parameters (e.g. pH, ionic strength, Cr(VI) initial concentration, amount of the adsorbent, temperature and contact time between metal ion and adsorbent) on the adsorption efficiency of Cr(VI) on dunite in aqueous solutions under atmospheric conditions. Evaluation of the experimental data shows that dunite presents increased affinity for Cr(VI) over a wide pH range and Cr(VI) concentration, and the experimental data are well fitted by the K(d) adsorption model. The relative adsorption is pH dependent and decreases slightly (about 10%) with increasing pH, because of changes in the surface charge of the solid. The effect of the ionic strength is significant (particularly at low pH), indicating the predominance of outer-sphere complexes. Moreover, adsorption experiments at various temperatures, two different pH values (pH 3 and pH 8) and three different ionic strengths (0.0, 0.1 and 1.0 M NaClO(4)), indicate an endothermic but spontaneous entropy-driven processes. PMID:21330733

  5. Adsorption modeling for off-gas treatment

    SciTech Connect

    Ladshaw, A.; Sharma, K.; Yiacoumi, S.; Tsouris, C.; De Paoli, D.W.

    2013-07-01

    Off-gas generated from the reprocessing of used nuclear fuel contains a mixture of several radioactive gases including {sup 129}I{sub 2}, {sup 85}Kr, HTO, and {sup 14}CO{sub 2}. Over the past few decades, various separation and recovery processes have been studied for capturing these gases. Adsorption data for gaseous mixtures of species can be difficult to determine experimentally. Therefore, procedures capable of predicting the adsorption behavior of mixtures need to be developed from the individual isotherms of each of the pure species. A particular isotherm model of interest for the pure species is the Generalized Statistical Thermodynamic Adsorption isotherm. This model contains an adjustable number of parameters and will therefore describe a wide range of adsorption isotherms for a variety of components. A code has been developed in C++ to perform the non-linear regression analysis necessary for the determination of the isotherm parameters, as well as the least number of parameters needed to describe an entire set of data. (authors)

  6. Adsorption of bovine serum albumin on nanosized magnetic particles.

    PubMed

    Peng, Z G; Hidajat, K; Uddin, M S

    2004-03-15

    Adsorption of bovine serum albumin (BSA) on nanosized magnetic particles (Fe(3)O(4)) was carried out in the presence of carbodiimide. The equilibrium and kinetics of the adsorption process were studied. Nanosized magnetic particles (Fe(3)O(4)) were prepared by the chemical precipitation method using Fe2+, Fe3+ salts, and ammonium hydroxide under a nitrogen atmosphere. Characterizations of magnetic particles were carried out using transmission electron microscopy (TEM) and a vibrating sample magnetometer (VSM). Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to confirm the attachment of BSA on magnetic particles. Effects of pH and salt concentrations were investigated on the adsorption process. The experimental results show that the adsorption of BSA on magnetic particles was affected greatly by the pH, while the effect of salt concentrations was insignificant at a low concentration range. The adsorption equilibrium isotherm was fitted well by the Langmuir model. The maximum adsorption of BSA on magnetic particles occurred at the isoelectric point of BSA. Adsorption kinetics was analyzed by a linear driving force mass-transfer model. BSA was desorbed from magnetic particles under alkaline conditions, which was confirmed by SDS-PAGE electrophoresis and FTIR results. PMID:14972603

  7. Adsorption of ammonia on treated stainless steel and polymer surfaces

    NASA Astrophysics Data System (ADS)

    Vaittinen, O.; Metsälä, M.; Persijn, S.; Vainio, M.; Halonen, L.

    2014-05-01

    Adsorption of dynamically diluted ammonia at part-per-billion to low part-per-million concentrations in dry nitrogen was studied with treated and non-treated stainless steel and polymer test tubes. The treatments included electropolishing and two types of coatings based on amorphous silicon. Cavity ring-down spectroscopy with an external cavity diode laser operating in the near-infrared wavelength range was used to monitor the adsorption process in real time in continuous-flow conditions to obtain quantitative assessment of the adsorptive properties of the studied surfaces. The investigated polymers were all less adsorptive than any of the treated or non-treated stainless steel surfaces. Some of the commercial coatings reduced the adsorption loss of stainless steel by a factor of ten or more. Polyvinylidene fluoride was found to be superior (less adsorption) to the four other studied polymer coatings. The number of adsorbed ammonia molecules per surface area obtained at different ammonia gas phase concentrations was modeled with Langmuir and Freundlich isotherms. The time behavior of the adsorption-desorption process occurring in the time scale of seconds and minutes was simulated with a simple kinetic model.

  8. Equilibrium, kinetic and thermodynamic studies on the adsorption of phenol onto graphene

    SciTech Connect

    Li, Yanhui; Du, Qiuju; Liu, Tonghao; Sun, Jiankun; Jiao, Yuqin; Xia, Yanzhi; Xia, Linhua; Wang, Zonghua; Zhang, Wei; Wang, Kunlin; Zhu, Hongwei; Wu, Dehai

    2012-08-15

    Graphical abstract: The effect of temperature on phenol adsorbed by graphene shows that the equilibrium adsorption capacity of phenol increases with the increase in temperature from 285 to 333 K. Increasing adsorption capacities with temperature indicates that the adsorption of phenol is controlled by an endothermic reaction. Highlights: ► The graphene has high phenol adsorption capacity. ► The graphene has a high specific surface area of 305 m{sup 2}/g. ► The adsorption capacity is high at acidic pH range. ► The graphene has rapid phenol adsorption rate. ► Phenol adsorption is a spontaneous and endothermic process. -- Abstract: Graphene, a new member of carbon family, has been prepared, characterized and used as adsorbent to remove phenol from aqueous solution. The effect parameters including pH, dosage, contact time, and temperature on the adsorption properties of phenol onto graphene were investigated. The results showed that the maximum adsorption capacity can reach 28.26 mg/g at the conditions of initial phenol concentration of 50 mg/L, pH 6.3 and 285 K. Adsorption data were well described by both Freundlich and Langmuir models. The kinetic study illustrated that the adsorption of phenol onto graphene fit the pseudo second-order model. The thermodynamic parameters indicated that the adsorption of phenol onto graphene was endothermic and spontaneous.

  9. Adsorption of highly charged Gaussian polyelectrolytes onto oppositely charged surfaces

    NASA Astrophysics Data System (ADS)

    Dutta, Sandipan; Jho, Y. S.

    2016-03-01

    In many biological processes highly charged biopolymers are adsorbed onto oppositely charged surfaces of macroions and membranes. They form strongly correlated structures close to the surface which cannot be explained by the conventional Poisson-Boltzmann theory. In this work strong coupling theory is used to study the adsorption of highly charged Gaussian polyelectrolytes. Two cases of adsorptions are considered, when the Gaussian polyelectrolytes are confined (a) by one charged wall, and (b) between two charged walls. The effects of salt and the geometry of the polymers on their adsorption-depletion transitions in the strong coupling regime are discussed.

  10. Adsorption of water vapor by homoionic montmorillonites: Heats of adsorption and desorption

    SciTech Connect

    Dios Cancela, G.; Huertas, F.J.; Romero Taboada, E.; Sanchez-Rasero, F.; Hernandez Laguna, A.

    1997-01-15

    Adsorption isotherms for water vapor, basal spacing, and immersion heats and water desorption heats of Li{sup +}, Na{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cu{sup 2+}, and Fe{sup 3+} montmorillonite are measured at various relative humidities (r.h.). The amount of water adsorbed as a function of r.h. is found to increase gradually, whereas basal spacing increases and the adsorption heat decreases in steps. The water desorption heat also decreases in steps. The entropy of adsorbed water appears to be negative with respect to the entropy of liquid water. A theoretical model is proposed to describe the hydration process of Li{sup +}, Na{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cu{sup 2+}, and Fe{sup 3+} montmorillonites. The experimental adsorption heats are found to have a direct relationship with the sum of the hydration energy of the cations plus expansion energy.

  11. Effect of pore blockage on adsorption isotherms and dynamics: Anomalous adsorption of iodine on activated carbon

    SciTech Connect

    Bhatia, S.K.; Liu, F.; Arvind, G.

    2000-04-18

    Isotherm hysteresis and pore-clocking effects of trapped molecules on adsorption dynamics is studied here, using the iodine-carbon system in the 300--343 K temperature range. It is found that a portion of the iodine is strongly adsorbed, and does not desorb, even over very long time scales, while the remainder adsorbs reversibly as a homogeneous monolayer with a Langmuirian isotherm in mesopores. The strongly adsorbed iodine appears to adsorb in micropores and at the mesopore mouths, hindering uptake of the reversible iodine. The uptake data for the adsorption and desorption dynamics of the reversible part is found to be best explained by means of a pore mouth resistance control mechanism. it is concluded that the dynamics of the adsorption and desorption at the pore mouth is important at early stages of the process.

  12. Studies of gas adsorption in flexible Metal-Organic frameworks

    NASA Astrophysics Data System (ADS)

    Sircar, Sarmishtha

    Flexible Metal-Organic frameworks that exhibit a gate-opening (GO) adsorption mechanism have potential for gas separations and gas storage. The GO phenomenon occurs when molecular gates in the structure expand/contract in response to the activation/de-activation of a system variable e.g. temperature, pressure or gas. Sharp discontinuities in the isotherm leading to S-shapes and large adsorption-desorption hysteresis are typical of this phenomenon. This study investigates the kinetics and thermodynamics of the GO behavior by combining adsorption measurements and analytical modeling of adsorption kinetics and capacity as a function of adsorbate, GO pressure, and temperature. Basic understanding of GO mechanism will help harness GO-MOF's as adsorbents for gas separations and storage. Experiments were performed on two precharacterized MOFs with verified GO behavior. These are (1) Zn2(bpdc)2(bpee), which expands from a relative amorphous to crystalline structure and (2) Cu[(dhbc) 2(4,4f-bpy)]H2O, a mutually interdigitated 2-D structure (bpdc = biphenyldicarboxylate, bpee = 1,2]bipyridylethene; DMF = N,N-dimethyl formamide, dhbc= 2,5-dihydroxybenzoic acid, bpy=bipyridine). Both sub- and super-critical adsorption data were collected using three adsorption units: a standard low-pressure volumetric adsorption unit, a commercial high-pressure gravimetric analyzer and a custom-built high-pressure differential volumetric unit. Collected laboratory data were combined with published adsorption rate and isotherm data for analysis to broaden the range of data collection. The accuracy of the high-pressure differential unit was improved by over 300-fold by changing analytical methods of processing data to establish a reliable null correction. A pronounced effect of the allowed experimental time was found at cryogenic temperatures on (1). Tightening the stability criteria used by the adsorption equipment to determine equilibration increased the experimental time from the order of

  13. Rethinking Critical Adsorption

    NASA Astrophysics Data System (ADS)

    Franck, Carl; Peach, Sarah; Polak, Robert D.

    1996-03-01

    Recent reflectivity experiments on near-critical mixtures of carbon disulfide and nitromethane contained in glass cells footnote Niraj S. Desai, Sarah Peach, and Carl Franck, Phys. Rev. E 52, 4129 (1995) have shown that preferential adsorption of one liquid component onto the wall can be controlled by chemical modification of the glass. The glass was treated with varying amounts of hexamethyldisilazane to decrease surface polarity and therefore enhance the adsorption of carbon disulfide in a surprisingly continuous way. The effect of the glass wall on the local liquid composition can be described by two different scaling hypotheses: using a short range field on the liquid closest to the wall, or pinning the amplitude of the order parameter at the surface. We have found that only the second approach is consistent with the experimental data, although this is difficult to reconcile with observed wetting critical phenomena. We also have reexamined the issue of substrate inhomogeneity and conclude that the substrates were indeed homogeneous on relevant length scales. Supported by the NSF under DMR-9320910 and the central facilities of the Materials Science Center at Cornell University.

  14. Adsorption behaviour of bulgur.

    PubMed

    Erbaş, Mustafa; Aykın, Elif; Arslan, Sultan; Durak, Atike N

    2016-03-15

    The aim of this research was to determine the adsorption behaviour of bulgur. Three different particle sizes (2adsorption, because of %E values lower than 10%. Bulgur must be stored below 70% relative humidity and with less than 10 g water per 100 g of dry mater. PMID:26575716

  15. Protein adsorption onto medical alloys: Voltage effects

    NASA Astrophysics Data System (ADS)

    Gettens, Robert T. T.

    This work examined the adsorption of an important-plasma protein, fibrinogen (Fb), onto a clinically-relevant-biomedical alloy, 316L stainless steel (SS) and electrically polarized 316L SS. Then, several key-interfacial properties important to protein adsorption were examined. The overriding role of electrochemical (EC) charge-transfer processes in the behavior of both the adsorption of Fb and interfacial properties was apparent. Adsorption of Fb onto polarized 316L SS was observed and quantified using both in situ and ex situ atomic force microscopy (AFM) techniques. Significant differences in Fb adsorption were observed across potential. Ex situ studies showed significantly lower area coverage and height of adsorbed Fb at cathodic potentials. In situ studies showed significantly slower kinetics below -100 mV. Current density data showed large charge-transfer processes (˜1x10 -5 to 1x10-4 A/cm2) taking place at voltages below -100 mV. A parallel-plate electrocapillary method was used to measure changes in metal-electrolyte surface energy (Deltagammasl) with potential. The results showed increasingly negative Deltagamma sl values on 316L SS at more cathodic voltages (i.e., more hydrophilic) and little to no change above -100 mV. These data correlate linearly with current density. Force measurements using a colloidal-AFM probe measured interfacial forces. Increasingly repulsive forces scaled with increasingly cathodic potentials; little interaction was detected at anodic potentials. These data correlated linearly with current density. The EC impedance was also studied. Electrochemical AFM (ECAFM) simultaneously gave impedance and structural changes with potential. Several regions of oxide topography/impedance characteristic were apparent which matched closely with the impedance behavior of the system. Through Mott-Schottky analysis the presence of the flatband potential was determined to be around -150 mV. Property observations of polarized 316L SS, specifically

  16. [Adsorption characteristics of f2 bacteriophages by four substrates in constructed wetland].

    PubMed

    Chen, Di; Zheng, Xiang; Wei, Yuan-Song; Yang, Yong

    2013-10-01

    Performance of f2 phages adsorption by four substrates including anthracite coal, steel slag, zeolite and forsterite was investigated through batch and dynamic experiments. Results of batch experiments showed that the removal efficiency of f2 phages by these four substrates was in the order of anthracite > steel slag > forsterite approximately zeolite. The adsorption of f2 phages by anthracite experienced fast, medium and slow stages, and the removal efficiency of f2 phages increased gradually with the increase of anthracite dosage, e. g. the optimized dosage of anthracite was 8.0 g at a solid/liquid ratio of 1:12.5 (m/V). The isothermal adsorption of all four substrates was described with Freundlich and Langmuir isothermal adsorption equation very well, and the adsorption of f2 phages by both anthracite and steel slag fitted pseudo-second order adsorption kinetics at their theoretical adsorption capacities of 3. 35 x 10(8) PFU.g-1 and 2.56 x 10(8) PFU.g-1, respectively, nearly the same as the equilibrium adsorption capacities obtained under the experiment conditions. And the liquid diffusion process was a rate-limiting step of the adsorption of f2 phage by both anthracite and steel slag, but not the only one. The results of dynamic adsorption experiments showed that the adsorption process of f2 phages in the three adsorption columns including anthracite, steel slag and zeolite experienced four stages of adaption, adsorption, pulse adsorption and adsorption equilibrium, and the total removal rates of f2 phages were more than 2. 55 Ig. PMID:24364309

  17. The Effect of Testosterone Replacement Therapy on Prostate-Specific Antigen (PSA) Levels in Men Being Treated for Hypogonadism

    PubMed Central

    Kang, De-Ying; Li, Hong-Jun

    2015-01-01

    Abstract Testosterone replacement therapy is used for the treatment of age-related male hypogonadism, and prostate-specific antigen (PSA) is a primary screening tool for prostate cancer. The systematic review and meta-analysis aimed to determine the effect of testosterone replacement therapy on PSA levels. Medline, Cochrane Library, EMBASE, and Google Scholar databases were searched until February 28, 2014, and inclusion criteria were as follows: randomized controlled trial; intervention group received testosterone/androgen replacement therapy; control group did not receive treatment; and no history of prostate cancer. The primary outcome was change of PSA level between before and after treatment. Secondary outcomes were elevated PSA level after treatment, and the number of patients who developed prostate cancer. After initially identifying 511 articles, 15 studies with a total of 739 patients that received testosterone replacement and 385 controls were included. The duration of treatment ranged from 3 to 12 months. Patients treated with testosterone tended to have higher PSA levels, and thus a greater change than those that received control treatments (difference in means of PSA levels = 0.154, 95% confidence interval [CI] 0.069 to 0.238, P < 0.001). The difference in means of PSA levels were significant higher for patients that received testosterone intramuscularly (IM) than controls (difference in means of PSA levels = 0.271, 95% CI 0.117–0.425, P = 0.001). Elevated PSA levels after treatment were similar between patients that received treatment and controls (odds ratio [OR] = 1.02, 95% CI 0.48–2.20, P = 0.953). Only 3 studies provided data with respect to the development of prostate cancer, and rates were similar between those that received treatment and controls. Testosterone replacement therapy does not increase PSA levels in men being treated for hypogonadism, except when it is given IM and even the increase with IM administration

  18. Circulating Total Testosterone and PSA Concentrations in a Nationally Representative Sample of Men Without a Diagnosis of Prostate Cancer

    PubMed Central

    Peskoe, Sarah B.; Joshu, Corinne E.; Rohrmann, Sabine; McGlynn, Katherine A.; Nyante, Sarah J.; Bradwin, Gary; Dobs, Adrian S.; Kanarek, Norma; Nelson, William G.; Platz, Elizabeth A.

    2015-01-01

    Background The association between serum sex steroid hormones and PSA in a general population has not been described. Methods Included were 378 men aged 40-85 years who participated in the National Health and Nutrition Examination Survey in 2001-2004, who did not have a prostate cancer diagnosis, and had not had a recent biopsy, rectal examination, cystoscopy, or prostate infection or inflammation. Serum total PSA, total testosterone, androstanediol glucuronide (3α-diol-G), estradiol, and sex hormone binding globulin (SHBG) concentrations were previously measured. Free testosterone was estimated by mass action. We applied sampling weights and calculated geometric mean PSA concentration by hormone quintiles adjusting for age and race/ethnicity, and also for body mass index, waist circumference, smoking, diabetes, and mutually for hormones. We estimated the OR of PSA ≥2.5 ng/mL per hormone quintile using logistic regression. Results Geometric mean PSA increased across testosterone quintiles after age and race/ethnicity (Q1: 0.80, Q5: 1.14 ng/mL; P-trend=0.002) and multivariable (Q1: 0.79, Q5: 1.16 ng/mL; P-trend=0.02) adjustment; patterns were similar for free testosterone and 3α-diol-G. SHBG was inversely associated with PSA only after multivariable adjustment (Q1: 1.32, Q5: 0.82 nmol/L; P-trend=0.01). Estradiol and PSA were not associated. The OR of PSA ≥2.5 ng/mL was 1.54 (95% CI 1.18-2.01) per testosterone quintile after age and race/ethnicity adjustment, and 1.78 (95% CI 1.16-2.73) after multivariable adjustment. Conclusions In this nationally representative sample, men with higher testosterone had higher PSA even after taking into account other hormones and modifiable factors. Men with higher SHBG had lower PSA, but only after multivariable adjustment. PMID:25919471

  19. Adsorption study of Ammonia Nitrogen by watermelon rind

    NASA Astrophysics Data System (ADS)

    Ibrahim, A.; Yusof, L.; Beddu, N. S.; Galasin, N.; Lee, P. Y.; Lee, R. N. S.; Zahrim, A. Y.

    2016-06-01

    The utilization of fruit waste for low-cost adsorbents as a replacement for costly conventional methods of removing ammonia nitrogen from wastewater has been reviewed. The adsorption studies were conducted as a function of contact time and adsorbent dosage and it were carried out on four different adsorbents; fresh watermelon rind and modified watermelon rind with sodium hydroxide (NaOH), potassium hydroxide (KOH) and sulphuric acid (H2SO4). Adsorbents were tested for characterization by using zeta potential test and all samples shows negative values thus makes it favourable for the adsorption process. The batch experimental result showed that adsorption process is rapid and equilibrium was established within 40 minutes of contact time. The ammonia nitrogen removal rate amounted in range of 96% to 99%, and the adsorption capacities were in range of 1.21 to 1.24 mg/g for all four different types of adsorbents used.

  20. Enhanced interpretation of adsorption data generated by liquid chromatography and by modern biosensors.

    PubMed

    Agmo Hernández, Víctor; Samuelsson, Jörgen; Forssén, Patrik; Fornstedt, Torgny

    2013-11-22

    In this study we demonstrate the importance of proper data processing in adsorption isotherm estimations. This was done by investigating and reprocessing data from five cases on two closely related platforms: liquid chromatography (LC) and biosensors. The previously acquired adsorption data were reevaluated and reprocessed using a three-step numerical procedure: (i) preprocessing of adsorption data, (ii) adsorption data analysis and (iii) final rival model fit. For each case, we will discuss what we really measure and what additional information can be obtained by numerical processing of the data. These cases clearly demonstrate that numerical processing of LC and biosensor data can be used to gain deeper understanding of molecular interactions with adsorption media. This is important because adsorption data, especially from biosensors, is often processed using old and simplified methods. PMID:23928411

  1. Adsorption kinetic character of copper ions onto a modified chitosan transparent thin membrane from aqueous solution.

    PubMed

    Cheng, Zihong; Liu, Xiaoshuai; Han, Mei; Ma, Wei

    2010-10-15

    A modified chitosan transparent thin membrane (MCTTM) was prepared and used as the adsorbent to investigate the adsorption kinetics due to excellent capacity of removing copper ions in water solution. The structure and morphology of MCTTM were characterized by SEM analysis and FTIR analysis. External mass transfer, intra particle diffusion, and pseudo-first and pseudo-second order models were used to describe the adsorption process. The results obtained from the study illustrated that the adsorption process could be described by the pseudo-second order model, which indicated adsorption process was a chemical adsorption behavior of chelation ion exchange proved by the FTIR and adsorption free energy analysis. External mass transfer and intra particle diffusion processes were the rate-controlling steps. PMID:20634000

  2. Removal of water and iodine by solid sorbents: adsorption isotherms and kinetics

    SciTech Connect

    Lin, R.; Tavlarides, L.L.

    2013-07-01

    Tritium and iodine-129 are two major radioactive elements that are present in off-gases from spent fuel reprocessing plants. Adsorption by solid sorbents is the state-of-the-art technique for removal of these species from off-gases. Modeling and simulating adsorption processes require accurate adsorption equilibrium and kinetic data to permit reasonable estimates of process parameters. We have developed a continuous flow single-pellet adsorption system to gather accurate adsorption equilibrium and kinetic data for adsorption of water by molecular sieve 3A and for adsorption of iodine by silver exchanged mordenite. In this paper, the design of the water and iodine adsorption experimental systems are briefly described and results of water adsorption experiments are presented and discussed. Water uptake curves are fitted with the linear-driving force (LDF) model and the shrinking-core model to determine kinetic parameters. It is shown that the kinetics of water adsorption on zeolite 3A under current experimental conditions is controlled by both the external film resistance and the macro-pore diffusion and can be predicted by both the LDF model and the shrinking-core model with the former one performing slightly better. Preliminary results from iodine adsorption experiments will be presented in the conference.

  3. Effects of CO/CO2/NO on elemental lead adsorption on carbonaceous surfaces.

    PubMed

    Gao, Zhengyang; Yang, Weijie

    2016-07-01

    The adsorption processes of elemental lead on carbonaceous surfaces which adsorbed CO/CO2/NO flue gases were investigated to understand the effects of CO/CO2/NO on elemental lead adsorption on carbonaceous surfaces with density functional theory. All calculations including optimizations, energies, and frequencies were conducted at B3PW91 density functional theory level, utilizing SDD basis set for lead and 6-31G(d) Pople basis set for other atoms. The results indicate that CO, CO2, and NO can promote the adsorption of elemental lead on the carbonaceous surface, but probably compete for adsorption sites with elemental lead. The promotion effects on adsorption can be attributed to active sites on the carbonaceous surface rather than flue gas adsorption on the carbonaceous surface. In addition, the adsorption order of three kinds of flue gas on the carbonaceous surface is CO2 > NO > CO > Pb on average. Furthermore, the enhancement order of three kinds of flue gas on the elemental lead adsorption on carbonaceous surfaces is CO-CS > CO2-CS > NO-CS > CS in general. In particular, atomic charge and adsorption energy have good linear relationship in the process of elemental lead adsorption. Graphical Abstract Competitive adsorption between flue gas and elemental lead on carbonaceous surfaces. PMID:27342251

  4. 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

  5. ADSORPTION MEDIA FOR ARSENIC REMOVAL

    EPA Science Inventory

    Presentation will discuss the use of adsorptive media for the removal of arsenic from drinking water. Presentation is a fundamental discussion on the use of adsorptive media for arsenic removal and includes information from several EPA field studies on removal of arsenic from dr...

  6. Kinetics and isotherms of Neutral Red adsorption on peanut husk.

    PubMed

    Han, Runping; Han, Pan; Cai, Zhaohui; Zhao, Zhenhui; Tang, Mingsheng

    2008-01-01

    Adsorption of Neutral Red (NR) onto peanut husk in aqueous solutions was investigated at 295 K. Experiments were carried out as function of pH, adsorbent dosage, contact time, and initial concentration. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, and Toth isotherm models. The results indicated that the Toth and Langmuir models provided the best correlation of the experimental data. The adsorption capacity of peanut husk for the removal of NR was determined with the Langmuir and found to be 37.5 mg/g at 295 K. The adsorption kinetic data were modeled using the pseudo-first order, pseudo-second order, and intra-particle diffusion kinetic equations. It was seen that the pseudo-first order and pseudo-second order kinetic equations could describe the adsorption kinetics. The intraparticle diffusion model was also used to express the adsorption process at the two-step stage. It was implied that peanut husk may be suitable as adsorbent material for adsorption of NR from aqueous solutions. PMID:19143308

  7. Arsenic adsorption from aqueous solutions by activated red mud.

    PubMed

    Altundoğan, H Soner; Altundoğan, Sema; Tümen, Fikret; Bildik, Memnune

    2002-01-01

    Heat treatment and acid treatment methods have been tested on red mud to increase its arsenic adsorption capability. The results indicate that the adsorptive capacity of red mud can be increased by acid treatment. This treatment causes sodalite compounds to leach out. As(III) and As(V) adsorption characteristics of activated red mud have similar tendencies with raw red mud. Batch adsorption studies have shown that activated red mud in dosages ranging from 20 to 100 g l(-1) can be used effectively to remove arsenic from aqueous solutions. The process is pH dependent, the optimum range being 5.8-7.5 for As(III) and 1.8-3.5 for As(V). The maximum removals are 96.52% for As(V) and 87.54% for As(III) for solutions with a final pH of 7.25 and 3.50, respectively, for the initial arsenic concentration of 133.5 micromol l(-1) (10 mg l(-1)), activated red mud dosage of 20 g l(-1), contact time of 60 min and temperature of 25 degrees C. The adsorption data obtained follow a first-order rate expression and fit the Langmuir isotherm well. Isotherms have been used to obtain the thermodynamic parameters. It was found that the adsorption of As(III) was exothermic, whereas As(V) adsorption was endothermic. PMID:11952183

  8. Adsorption of cadmium(II) on waste biomaterial.

    PubMed

    Baláž, M; Bujňáková, Z; Baláž, P; Zorkovská, A; Danková, Z; Briančin, J

    2015-09-15

    Significant increase of the adsorption ability of the eggshell biomaterial toward cadmium was observed upon milling, as is evidenced by the value of maximum monolayer adsorption capacity of 329mgg(-1), which is markedly higher than in the case of most "green" sorbents. The main driving force of the adsorption was proven to be the presence of aragonite phase as a consequence of phase transformation from calcite occurring during milling. Cadmium is adsorbed in a non-reversible way, as documented by different techniques (desorption tests, XRD and EDX measurements). The optimum pH for cadmium adsorption was 7. The adsorption process was accompanied by the increase of the value of specific surface area. The course of adsorption has been described by Langmuir, Freundlich and Dubinin-Radushkevich isotherms. The adsorption kinetics was evaluated using three models, among which the best correlation coefficients and the best normalized standard deviation values were achieved for the pseudo-second order model and the intraparticle diffusion model, respectively. PMID:26005798

  9. Boronate affinity adsorption of RNA: possible role of conformational changes

    NASA Technical Reports Server (NTRS)

    Singh, N.; Willson, R. C.; Fox, G. E. (Principal Investigator)

    1999-01-01

    Batch equilibrium adsorption isotherm determination is used to characterize the adsorption of mixed yeast RNA on agarose-immobilized m-aminophenylboronic acid. It is shown that the affinity-enhancing influence of divalent cations depends strongly on the precise nature of the cation used, with barium being far more effective than the conventionally-used magnesium. This adsorption-promoting influence of barium is suggested to arise primarily from ionic influences on the structure and rigidity of the RNA molecule, as the adsorption of ribose-based small molecules is not similarly affected. The substitution of barium for the standard magnesium counterion does not greatly promote the adsorption of DNA, implying that the effect is specific to RNA and may be useful in boronate-based RNA separations. RNA adsorption isotherms exhibit sharp transitions as functions of temperature, and these transitions occur at different temperatures with Mg2+ and with Ba2+. Adsorption affinity and capacity were found to increase markedly at lower temperatures, suggestive of an enthalpically favored interaction process. The stoichiometric displacement parameter, Z, in Ba2+ buffer is three times the value in Mg2+ buffer, and is close to unity.

  10. Clinical variables associated with PSA response to abiraterone acetate in patients with metastatic castration-resistant prostate cancer

    PubMed Central

    Leibowitz-Amit, R.; Templeton, A. J.; Omlin, A.; Pezaro, C.; Atenafu, E. G.; Keizman, D.; Vera-Badillo, F.; Seah, J.-A.; Attard, G.; Knox, J. J.; Sridhar, S. S.; Tannock, I. F.; de Bono, J. S.; Joshua, A. M.

    2014-01-01

    Background Abiraterone acetate (abiraterone) prolongs overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC). This study's objective was to retrospectively identify factors associated with prostate-specific antigen (PSA) response to abiraterone and validate them in an independent cohort. We hypothesized that the neutrophil/lymphocyte ratio (NLR), thought to be an indirect manifestation of tumor-promoting inflammation, may be associated with response to abiraterone. Patients and methods All patients receiving abiraterone at the Princess Margaret (PM) Cancer Centre up to March 2013 were reviewed. The primary end point was confirmed PSA response defined as PSA decline ≥50% below baseline maintained for ≥3 weeks. Potential factors associated with PSA response were analyzed using univariate and multivariable analyses to generate a score, which was then evaluated in an independent cohort from Royal Marsden (RM) NHS foundation. Results A confirmed PSA response was observed in 44 out of 108 assessable patients (41%, 95% confidence interval 31%–50%). In univariate analysis, lower pre-abiraterone baseline levels of lactate dehydrogenase, an NLR ≤ 5 and restricted metastatic spread to either bone or lymph nodes were each associated with PSA response. In multivariable analysis, only low NLR and restricted metastatic spread remained statistically significant. A score derived as the sum of these two categorical variables was associated with response to abiraterone (P = 0.007). Logistic regression analysis on an independent validation cohort of 245 patients verified that this score was associated with response to abiraterone (P = 0.003). It was also associated with OS in an exploratory analysis. Conclusions A composite score of baseline NLR and extent of metastatic spread is associated with PSA response to abiraterone and OS. Our data may help understand the role of systemic inflammation in mCRPC and warrant further research. PMID

  11. [Usefulness of hyper sensitive PSA assay kits for determination on low range of prostate specific antigen in prostate cancer].

    PubMed

    Akimoto, S; Akakura, K; Ohki, T; Shimazaki, J; Kuriyama, M; Kawada, Y

    1995-02-01

    Prostate specific antigen (PSA) levels after total prostatectomy or radiation therapy to localized prostate cancer and also during endocrine therapy are within normal range. Therefore, it is necessary to use hyper sensitive PSA assay kits for early detection of relapse. The present study was undertaken to evaluate two hyper sensitive assay kits (Delfia kit, lower limit 0.1 ng/ml, Kabi Pharmacia Diagnostics Co. and Markit M kit, 0.5 ng/ml, Dainippon Pharmaceutical Co.) and to compare them with conventional PSA kit (Eiken Chemical Co., 1.0 ng/ml). Total of 291 sera were examined: patients consisted of 10 total prostatectomy+endocrine therapy, 9 radiation therapy+endocrine therapy, 5 radiation therapy alone and 44 endocrine therapy alone. Values of endocrine therapy alone were divided into two groups according to duration after start of treatment; more or less than 5 years. The following results were obtained. 1. In non-relapse patients after total prostatectomy+endocrine therapy and radiation+endocrine therapy, PSA showed under lower limit with hyper sensitive kit. On the contrary, conventional kit indicated more than 1.0 ng/ml. 2. Radiation therapy alone kept PSA in detectable range with hyper sensitive kit in spite of no sign of relapse. 3. In non-relapsed patients under endocrine therapy alone, long duration (more than 5 years after start of treatment) decreased PSA in non detectable values with hyper sensitive kits. In this case, conventional kit still showed PSA as more than 1 ng/ml. 4. Doubling time at relapse was estimated similar with Delfia kit and Markit M kit, and much longer with conventional kit. It is concluded that hyper sensitive kit is more useful to manage patients after therapy than conventional kit. PMID:7534843

  12. Oral selenium supplementation has no effect on PSA velocity in men undergoing active surveillance for localized prostate cancer

    PubMed Central

    Stratton, M. S.; Algotar, A. M.; Ranger-Moore, J.; Stratton, S. P.; Slate, E.; Hsu, C.H; Thompson, P.A.; Clark, L. C.; Ahmann, F. R.

    2015-01-01

    Introduction The Nutritional Prevention of Cancer Trial demonstrated a 52% lower incidence of prostate cancer in men supplemented with selenium. As a result, our study was designed to assess whether selenium supplementation attenuates the progression of prostate cancer. Methods A Phase 2 randomized, double-blind, placebo-controlled clinical trial was conducted in men with localized non-metastatic prostate cancer who had elected to forgo active treatment and be followed by active surveillance. A total of 140 men were randomized to placebo (n=46), 200 μg/day (n=47) or 800 μg/day (n=47) selenium p.o. (as selenized yeast) and followed every 3 months for up to 5 years. PSA velocity was used as a marker of prostate cancer progression and was estimated using mixed effects regression. Results Adjusting for age, body mass index, baseline selenium, smoking, baseline PSA, race, PSA method, and Gleason score; PSA velocities for 200 μg/day and 800 μg/day treatment groups were not statistically significantly different from placebo (p = 0.32 and p = 0.61 respectively). In the highest quartile of baseline selenium, men supplemented with 800 μg selenium demonstrated PSA velocity statistically significantly higher as compared to placebo (p = 0.018). Conclusions Selenium supplementation did not show a protective effect on PSA velocity in subjects with localized prostate cancer. On the contrary, supplementation with high dose selenium was observed to be a risk factor for increased PSA velocity in men with high baseline plasma selenium concentrations. Trial registration clinicaltrials.gov (NCT00752739) PMID:20647337

  13. 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.

  14. Analysis of Serum Total and Free PSA Using Immunoaffinity Depletion Coupled to SRM: Correlation with Clinical Immunoassay Tests

    SciTech Connect

    Liu, Tao; Hossain, Mahmud; Schepmoes, Athena A.; Fillmore, Thomas L.; Sokoll, Lori J.; Kronewitter, Scott R.; Izmirlian, Grant; Shi, Tujin; Qian, Weijun; Leach, Robin; Thompson, Ian M.; Chan, Daniel W.; Smith, Richard D.; Kagan, Jacob; Srinivastava, Sudhir; Rodland, Karin D.; Camp, David G.

    2012-08-03

    Sandwich immunoassay is the standard technique used in clinical labs for quantifying protein biomarkers for disease detection, monitoring and therapeutic intervention. Albeit highly sensitive, the development of a specific immunoassay is rather time-consuming and associated with extremely high cost due to the requirement for paired immunoaffinity reagents of high specificity. Recently, mass spectrometry-based methods, specifically selected reaction monitoring mass spectrometry (SRM-MS), have been increasingly applied to measure low abundance biomarker candidates in tissue and biofluids, owing to high sensitivity and specificity, simplicity of assay configuration, and great multiplexing capability. In this study, we report for the first time the development of immunoaffinity depletion-based workflows and SRM-MS assays that enable sensitive and accurate quantification of total and free prostate-specific antigen (PSA) in serum without the requirement for specific PSA antibodies. With stable isotope dilution and external calibration, low ng/mL level detection of both total and free PSA was consistently achieved in both PSA-spiked female serum samples and actual patient serum samples. Moreover, comparison of the results obtained when SRM PSA assays and conventional immunoassays were applied to the same samples showed very good correlation (R2 values ranging from 0.90 to 0.99) in several independent clinical serum sample sets, including a set of 33 samples assayed in a blinded test. These results demonstrate that the workflows and SRM assays developed here provide an attractive alternative for reliably measuring total and free PSA in human blood. Furthermore, simultaneous measurement of free and total PSA and many other biomarkers can be performed in a single analysis using high-resolution liquid chromatographic separation coupled with SRM-MS.

  15. Albumin adsorption on CoCrMo alloy surfaces

    PubMed Central

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

    2015-01-01

    Proteins can adsorb on the surface of artificial joints immediately after being implanted. Although research studying protein adsorption on medical material surfaces has been carried out, the mechanism of the proteins’ adsorption which affects the corrosion behaviour of such materials still lacks in situ observation at the micro level. The adsorption of bovine serum albumin (BSA) on CoCrMo alloy surfaces was studied in situ by AFM and SKPFM as a function of pH and the charge of CoCrMo alloy surfaces. Results showed that when the specimens were uncharged, hydrophobic interaction could govern the process of the adsorption rather than electrostatic interaction, and BSA molecules tended to adsorb on the surfaces forming a monolayer in the side-on model. Results also showed that adsorbed BSA molecules could promote the corrosion process for CoCrMo alloys. When the surface was positively charged, the electrostatic interaction played a leading role in the adsorption process. The maximum adsorption occurred at the isoelectric point (pH 4.7) of BSA. PMID:26673525

  16. Albumin adsorption on CoCrMo alloy surfaces

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Proteins can adsorb on the surface of artificial joints immediately after being implanted. Although research studying protein adsorption on medical material surfaces has been carried out, the mechanism of the proteins’ adsorption which affects the corrosion behaviour of such materials still lacks in situ observation at the micro level. The adsorption of bovine serum albumin (BSA) on CoCrMo alloy surfaces was studied in situ by AFM and SKPFM as a function of pH and the charge of CoCrMo alloy surfaces. Results showed that when the specimens were uncharged, hydrophobic interaction could govern the process of the adsorption rather than electrostatic interaction, and BSA molecules tended to adsorb on the surfaces forming a monolayer in the side-on model. Results also showed that adsorbed BSA molecules could promote the corrosion process for CoCrMo alloys. When the surface was positively charged, the electrostatic interaction played a leading role in the adsorption process. The maximum adsorption occurred at the isoelectric point (pH 4.7) of BSA.

  17. High temperature adsorption measurements

    SciTech Connect

    Bertani, R.; Parisi, L.; Perini, R.; Tarquini, B.

    1996-01-24

    Adsorption phenomena are a rich and rather new field of study in geothermal research, in particular at very high temperature. ENEL is interested in the exploitation of geothermal regions with superheated steam, and it is important to understand the behavior of water-rock interaction. We have analyzed in the 170-200 °C temperature range four samples of Monteverdi cuttings; the next experimental effort will be at 220 °C and over in 1996. The first results of the 1995 runs are collected in this paper. We can highlight four main items: 1. At relative pressures over 0.6 the capillarity forces are very important. 2. There is no significant temperature effect. 3. Adsorbed water can be present, and it is able to multiply by a factor of 15 the estimated reserve of super-heated steam only. 4. Pores smaller than 15 Å do not contribute to the adsorbed mass.

  18. High temperature adsorption measurements

    SciTech Connect

    Bertani, R.; Parisi, L.; Perini, R.; Tarquini, B.

    1996-12-31

    Adsorption phenomena are a rich and rather new field of study in geothermal research, in particular at very high temperature. ENEL is interested in the exploitation of geothermal regions with super-heated steam, and it is important to understand the behavior of water-rock interaction. We have analyzed in the 170-200{degrees}C temperature range four samples of Monteverdi cuttings; the next experimental effort will be at 220{degrees}C and over in 1996. The first results of the 1995 runs are collected in this paper. We can highlight four main items: (1) At relative pressures over 0.6 the capillarity forces are very important. (2) There is no significant temperature effect. (3) Adsorbed water can be present, and it is able to multiply by a factor of 15 the estimated reserve of super-heated steam only. (4) Pores smaller than 15 {Angstrom} do not contribute to the adsorbed mass.

  19. Chromium adsorption by lignin

    SciTech Connect

    Lalvani, S.B.; Huebner, A.; Wiltowski, T.S.

    2000-01-01

    Hexavalent chromium is a known carcinogen, and its maximum contamination level in drinking water is determined by the US Environmental Protection Agency (EPA). Chromium in the wastewaters from plating and metal finishing, tanning, and photographic industries poses environmental problems. A commercially available lignin was used for the removal of hexavalent as well as trivalent chromium from aqueous solution. It is known that hexavalent chromium is present as an anionic species in the solution. It was found that lignin can remove up to 63% hexavalent and 100% trivalent chromium from aqueous solutions. The removal of chromium ions was also investigated using a commercially available activated carbon. This absorbent facilitated very little hexavalent and almost complete trivalent chromium removal. Adsorption isotherms and kinetics data on the metal removal by lignin and activated carbon are presented and discussed.

  20. Synthesis of Ordered Mesoporous Silica for Energy-efficient Adsorption Systems

    NASA Astrophysics Data System (ADS)

    Endo, Akira; Komori, Kou; Inagi, Yuki; Fujisaki, Satoko; Yamamoto, Takuji

    Energy-efficient adsorption systems, such as adsorption heat pump, desiccant cooling, humidity control system, and so on, are expected as a energy exchange process because they are able to utilize low temperature exhaust heat. As an adsorbent for such systems, materials with large adsorption capacity in the pressure range of practical operation are preferable. To enable the design and synthesis of materials with large heat storage capacity, the pore structure of adsorbents should be optimized for each systems. In this paper, we synthesized ordered mesoporous silica (MPS) with an arrow pore size distribution of around 2nm by a solvent evaporation method and evaluated their water adsorption properties. The adsorption isotherms for MPSs showed steep increase at a relative humidity corresponding to their pore size. Since MPSs have a large adsorption capacity than conventional materials in the relative humidity region of practical operation, they are expected for new adsorbents for energy-efficient adsorption systems.

  1. Adsorption and isothermal models of atrazine by zeolite prepared from Egyptian kaolin

    NASA Astrophysics Data System (ADS)

    Jamil, Tarek S.; Gad-Allah, Tarek A.; Ibrahim, Hanan S.; Saleh, Tamer S.

    2011-01-01

    The adsorption behavior of Atrazine on zeolites, prepared from Egyptian kaolin, has been studied in order to consider the application of these types of zeolites in water purification. The batch mode has been employed, using atrazine solution of concentration ranging from 2 to 10 mg /l. The adsorption capacity and distribution coefficients ( Kd) were determined for the adsorption system as a function of sorbate concentration. It was found that, under the studies concentrations, the percent of adsorbed atrazine on both zeolites match to Langmuir and Freundlich adsorption models. The constants of each model were calculated to assess the adsorption behavior of atrazine on each type of zeolite. According to the equilibrium studies, adsorption of atrazine on zeolite X at lower concentrations is much better than that on zeolite A. The application of Dublin-Kaganer-Radushkevich model revealed physisorption endothermic adsorption process for both zeolites. These results show that natural zeolites hold great potential to remove hazardous materials such as atrazine from water.

  2. Effect of nitrogen doping of graphene oxide on hydrogen and hydroxyl adsorption

    NASA Astrophysics Data System (ADS)

    Min, Byeong June; Jeong, Hae Kyung

    2014-05-01

    We investigate how nitrogen-doping affects the hydrogen (H) and the hydroxyl (OH) adsorption on graphene oxide (GO) and on nitrogen-doped GO (NGO) via pseudopotential plane wave density functional calculations within the local spin density approximation. We find that the nitrogendoping brings about drastic changes in the hydrogen and the hydroxyl adsorption energetics, but its effects depend sensitively on the nitrogen configuration in NGO. The H and the OH adsorption energies are comparable only for pyrrolic NGO. In GO and quarternary NGO, the H adsorption energy is greater than the OH adsorption energy while the trend is reversed in pyridinic NGO. Also, the OH adsorption process is less affected by nitrogen-doping than the H adsorption is.

  3. High-capacity adsorption of aniline using surface modification of lignocellulose-biomass jute fibers.

    PubMed

    Gao, Da-Wen; Hu, Qi; Pan, Hongyu; Jiang, Jiping; Wang, Peng

    2015-10-01

    Pyromellitic dianhydride (PMDA) modified jute fiber (MJF) were prepared with microwave treatment to generate a biosorbent for aniline removal. The characterization of the biosorbent was investigated by SEM, BET and FT-IR analysis to discuss the adsorption mechanism. The studies of various factors influencing the adsorption behavior indicated that the optimum dosage for aniline adsorption was 3g/L, the maximum adsorption capacity was observed at pH 7.0 and the adsorption process is spontaneous and endothermic. The aniline adsorption follows the pseudo second order kinetic model and Langmuir isotherm model. Moreover, the biosorbent could be regenerated through the desorption of aniline by using 0.5M HCl solution, and the adsorption capacity after regeneration is even higher than that of virgin MJF. All these results prove MJF is a promising adsorbent for aniline removal in wastewater. PMID:26172392

  4. Adsorptive removal of methylene blue by CuO-acid modified sepiolite as effective adsorbent and its regeneration with high-temperature gas stream.

    PubMed

    Su, Chengyuan; Wang, Liang; Chen, Menglin; Huang, Zhi; Lin, Xiangfeng

    2016-01-01

    In this study, the dynamic adsorption of methylene blue dye onto CuO-acid modified sepiolite was investigated. Meanwhile, the equilibrium and kinetic data of the adsorption process were studied to understand the adsorption mechanism. Furthermore, a high-temperature gas stream was applied to regenerate the adsorbent. The results showed that the Langmuir isotherm model was applied to describe the adsorption process. The positive value of enthalpy change indicated that the adsorption process was endothermic in nature. In the dynamic adsorption process, the best adsorption performance was achieved when the ratio of column height to diameter was 2.56 and the treatment capacity was 6 BV/h. The optimal scenario for regeneration experiments was the regeneration temperature of 550-650 °C, the space velocity of 100 min(-1) and the regeneration time of 10 min. The effective adsorption of CuO-acid modified sepiolite was kept for 12 cycles of adsorption and regeneration. PMID:27533859

  5. 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

  6. Elecsys CEA, PSA and AFP. Clinical results of a multicentre evaluation.

    PubMed

    Uhl, W; Chan, D W; Jones, K; Kelley, C; Assmann, G; von Eckardstein, A; Sägers, A; Yvert, J P; Schneider, A M; Torralba, A; Fuentes-Arderiu, X; Gonzalez de la Presa, B; Vives, M; Greiling, H; Eberle, A; Niederau, C M; Cremer, P; Reiter, W; Vogeser, M; Neumeier, D; Luppa, P; Huber, U

    1998-01-01

    Three tumormarker assays, Elecsys CEA, PSA and AFP, have been evaluated in an international multicentre study to characterize their clinical performance and to verify the comparability with the corresponding tests of the Enzymun-Test product line and other methods. For each of the markers results were obtained from four laboratories. On the basis of 314 and 199 specimens respectively, (preliminary) reference ranges could be established for CEA and PSA. For the prostate marker, the age dependence of the antigen level could be clearly confirmed. Mean concentrations range between 0.51 ng/ml (< 40 years) and 3.57 ng/ml (> 70 years). Referring to CEA, 95th percentiles of 4.31 ng/ml and 2.69 ng/ml were elaborated for smokers and nonsmokers. In general, good to excellent correlations (r > 0.98) were found between the Elecsys and Enzymun-Tests. Regarding the systematic comparability of both systems, most of the slopes derived from the individual method comparison studies are within the +/- 10% range of the respective standardization results. The specific distribution pattern of the individual tumormarker values elaborated with sample material of known clinical background, reflects the well established categorization of different benign and malignant diseases according to their characteristic marker levels. Of utmost importance, however, is the excellent comparability of the Elecsys assays with the corresponding Enzymun-Tests and the FDA approved AIA 1200 tests from TOSOH in follow-up studies. Almost superimposable concentration curves guarantee that identical diagnostic information is derived from all three methods. Especially for PSA, a series of measurements on sera of prostatectomized patients proved the usability and clinical value of the test also for this particular indication. For either one of the Elecsys tests, the feasibility of using plasma as sample material was verified. PMID:9677672

  7. Adsorption behaviour of direct yellow 50 onto cotton fiber: equilibrium, kinetic and thermodynamic profile.

    PubMed

    Ismail, L F M; Sallam, H B; Abo Farha, S A; Gamal, A M; Mahmoud, G E A

    2014-10-15

    This study investigated the adsorption of direct yellow 50 onto cotton fiber from aqueous solution by using parameters, such as pH, temperature, contact time, initial dye concentration and the effect of sodium sulphate, tetrasodium edate and trisodium citrate. The extent of dye adsorption increased with increasing contact time, temperature and solution concentration. The experimental data were analyzed by the Langmuir and Freundlich models of adsorption. It was found that the Langmuir equation fit better than the Freundlich equation. The results show that the presence of SE and SC significantly enhance the dye adsorption onto cotton fiber. In addition, the adsorption data obtained at different temperatures of DY50 onto cotton fiber were applied to pseudo first-order, pseudo second-order and intraparticle diffusion models. The rates of adsorption were found to conform to pseudo second-order kinetics with good correlation. Also, free energy of adsorption (ΔG(#)), enthalpy (ΔH(#)), and entropy (ΔS(#)) changes were determined to predict the nature of adsorption. The positive value of the enthalpy change indicated that the adsorption is endothermic process. The activation energy, Ea, is ranged between 1.9 and 3.9kJmol(-1) indicated that the adsorption process is a physisorption. This low value of Ea generally indicates diffusion controlled process. PMID:24882703

  8. Selective adsorption and separation of organic dyes from aqueous solution on polydopamine microspheres.

    PubMed

    Fu, Jianwei; Xin, Qianqian; Wu, Xuechen; Chen, Zhonghui; Yan, Ya; Liu, Shujun; Wang, Minghuan; Xu, Qun

    2016-01-01

    Polydopamine (PDA) microspheres, synthesized by a facile oxidation polymerization route, were evaluated as a potential adsorbent for selective adsorption and separation of organic dyes. The adsorption processes towards nine water-soluble dyes (anionic dyes: methyl orange (MO), eosin-Y (EY), eosin-B (EB), acid chrome blue K (ACBK), neutral dye: neutral red (NR), and cationic dyes: rhodamine B (RhB), malachite green (MG), methylene blue (MB), safranine T (ST)) were thoroughly investigated. The adsorption selectivity of organic dyes onto PDA microspheres was successfully applied for the separation of dyes mixtures. Various influential factors such as solution pH, temperature, and contact time were employed to ascertain the optimal condition for adsorption of representative organic dyes including MB, MG and NR. The pseudo-first-order and pseudo-second-order kinetics models were used to fit the adsorption kinetics process. Five isothermal adsorption models (Langmuir, Dubnin-Radushkevich, Temkin, Freundlich and Harkins-Jura) were used to investigate the adsorption thermodynamics properties. The results showed that the PDA microspheres owned good selective adsorption ability towards cationic dyes. The adsorption kinetics process conformed to the pseudo-second-order kinetics model and the Langmuir isotherm model was more appropriate for tracing the adsorption behavior than other isotherm models. Thus, we can conclude PDA microspheres may be a high-efficiency selective adsorbent towards some cationic dyes. PMID:26407057

  9. Adsorption of cadmium by biochar derived from municipal sewage sludge: Impact factors and adsorption mechanism.

    PubMed

    Chen, Tan; Zhou, Zeyu; Han, Rong; Meng, Ruihong; Wang, Hongtao; Lu, Wenjing

    2015-09-01

    Static equilibrium experiments were carried out to investigate the impact factors and the mechanism of cadmium adsorption on biochar derived from municipal sewage sludge. An appropriate dosage of biochar is sufficient; in the experiment, 0.2% is the optimal dosage for the largest removal capacity, while the removal capacity of biochar reduces with the increasing dosage. pH is another dominant factor of the adsorption process. The removal capacity of biochar is lower than 20 mg·g(-1) when the solution initial pH is lower than 2 pH units, comparatively retaining more than 40 mg·g(-1) at the solution initial pH higher than 3 pH units. Temperature has weak influence on the adsorptive performance. The main mechanism of the adsorption process of biochar for cadmium mainly involves (1) surface precipitation by forming insoluble cadmium compounds in alkaline condition, and (2) ion exchange for cadmium with exchangeable cations in the biochar, such as calcium ions. PMID:25966459

  10. A comparative adsorption study: 17β-estradiol onto aerobic granular sludge and activated sludge.

    PubMed

    Zheng, Xiao-ying; He, Yu-jie; Chen, Wei; Wang, Ming-yang; Cao, Su-lan; Ni, Ming; Chen, Yu

    2016-01-01

    Adsorption plays a significant role in removing hydrophobic 17β-estradiol (E2) from wastewater. Batch experiments were conducted to compare the adsorption of E2 onto activated aerobic granular sludge (AGS) and activated sludge (AS), and features evaluated included the adsorption kinetics, thermodynamics, and influence of other environmental factors. By using a non-chemical wet-heat technique, both AGS and AS were treated to inactivated status. Then, after loading E2, the adsorption equilibrium capacity of the AGS was found to be greater than that of the AS at the same initial concentration of E2. Moreover, both the adsorption processes corresponded to a pseudo-second-order kinetic model; the adsorption rate constant of AGS was found to be higher and the half-adsorption time was shorter than that of AS. Next, evaluations of adsorption isotherms and thermodynamics indicated that the adsorption process was mainly a physical process. Lower temperatures facilitated a higher equilibrium adsorption capacity. However, the adsorption binding sites of AGS were distributed more uniformly at higher temperature, in contrast to the distribution found for AS. Finally, acidic conditions and an appropriate ionic strength (0.4 mol/L) were found to be particularly conducive to the adsorption process. Overall, the results showed that AGS has the potential to adsorb E2 with significant efficiency, thereby offering a new and more efficient means of treating E2 and trace oestrogens in wastewater. PMID:26209151

  11. 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

  12. Adsorptive separation of propylene-propane mixtures

    SciTech Connect

    Jaervelin, H.; Fair, J.R. )

    1993-10-01

    The separation of propylene-propane mixtures is of great commercial importance and is carried out by fractional distillation. It is claimed to be the most energy-intensive distillation practiced in the United States. The purpose of this paper is to describe experimental work that suggests a practical alternative to distillation for separating the C[sub 3] hydrocarbons: adsorption. As studied, the process involves three adsorptive steps: initial separation with molecular sieves with heavy dilution with an inert gas; separation of propylene and propane separately from the inert gas, using activated carbon; and drying of the product streams with any of several available desiccants. The research information presented here deals with the initial step and includes both equilibrium and kinetic data. Isotherms are provided for propylene and propane adsorbed on three zeolites, activated alumina, silica gel, and coconut-based activated carbon. Breakthrough data are provided for both adsorption and regeneration steps for the zeolites, which were found to be superior to the other adsorbents for breakthrough separations. A flow diagram for the complete proposed process is included.

  13. Aqueous mercury adsorption by activated carbons.

    PubMed

    Hadi, Pejman; To, Ming-Ho; Hui, Chi-Wai; Lin, Carol Sze Ki; McKay, Gordon

    2015-04-15

    Due to serious public health threats resulting from mercury pollution and its rapid distribution in our food chain through the contamination of water bodies, stringent regulations have been enacted on mercury-laden wastewater discharge. Activated carbons have been widely used in the removal of mercuric ions from aqueous effluents. The surface and textural characteristics of activated carbons are the two decisive factors in their efficiency in mercury removal from wastewater. Herein, the structural properties and binding affinity of mercuric ions from effluents have been presented. Also, specific attention has been directed to the effect of sulfur-containing functional moieties on enhancing the mercury adsorption. It has been demonstrated that surface area, pore size, pore size distribution and surface functional groups should collectively be taken into consideration in designing the optimal mercury removal process. Moreover, the mercury adsorption mechanism has been addressed using equilibrium adsorption isotherm, thermodynamic and kinetic studies. Further recommendations have been proposed with the aim of increasing the mercury removal efficiency using carbon activation processes with lower energy input, while achieving similar or even higher efficiencies. PMID:25644627

  14. Adsorption of polymeric brushes: Bridging

    NASA Astrophysics Data System (ADS)

    Johner, Albert; Joanny, Jean-François

    1992-04-01

    We study the adsorption of grafted polymer layers on a planar surface parallel to the grafting surface. The layer consists of two types of chains: nonadsorbed chains with a free end and adsorbed chains forming bridges between the two plates. In the limit of strong adsorption a dead zone exists in the vicinity of the adsorbing plate; its size increases with the adsorption strength. Two adsorption mechanisms are possible: adsorption of the last monomer only and adsorption of all the monomers. In both cases the adsorption regimes at equilibrium (when no external force acts on the plates) are discussed within the framework of the self-consistent mean-field theory. We also give scaling laws taking into account excluded volume correlations. Finally, we consider situations where a finite external force, either tangential or normal to the plates, is applied on the adsorbing plate. Pulling and tangential forces both reduce the fraction of bridges and eventually lead to rupture, whereas compressional forces favor bridging. For normal forces, force vs distance profiles between planes and crossed cylinders are given.

  15. Removal of mercury by adsorption: a review.

    PubMed

    Yu, Jin-Gang; Yue, Bao-Yu; Wu, Xiong-Wei; Liu, Qi; Jiao, Fei-Peng; Jiang, Xin-Yu; Chen, Xiao-Qing

    2016-03-01

    Due to natural and production activities, mercury contamination has become one of the major environmental problems over the world. Mercury contamination is a serious threat to human health. Among the existing technologies available for mercury pollution control, the adsorption process can get excellent separation effects and has been further studied. This review is attempted to cover a wide range of adsorbents that were developed for the removal of mercury from the year 2011. Various adsorbents, including the latest adsorbents, are presented along with highlighting and discussing the key advancements on their preparation, modification technologies, and strategies. By comparing their adsorption capacities, it is evident from the literature survey that some adsorbents have shown excellent potential for the removal of mercury. However, there is still a need to develop novel, efficient adsorbents with low cost, high stability, and easy production and manufacture for practical utility. PMID:26620868

  16. Adsorption of Atmospheric Gases on Pu Surfaces

    SciTech Connect

    Nelson, A J; Holliday, K S; Stanford, J A; Grant, W K; Erler, R G; Allen, P G; McLean, W; Roussel, P

    2012-03-29

    Surface adsorption represents a competition between collision and scattering processes that depend on surface energy, surface structure and temperature. The surface reactivity of the actinides can add additional complexity due to radiological dissociation of the gas and electronic structure. Here we elucidate the chemical bonding of gas molecules adsorbed on Pu metal and oxide surfaces. Atmospheric gas reactions were studied at 190 and 300 K using x-ray photoelectron spectroscopy. Evolution of the Pu 4f and O 1s core-level states were studied as a function of gas dose rates to generate a set of Langmuir isotherms. Results show that the initial gas dose forms Pu{sub 2}O{sub 3} on the Pu metal surface followed by the formation of PuO{sub 2} resulting in a layered oxide structure. This work represents the first steps in determining the activation energy for adsorption of various atmospheric gases on Pu.

  17. Analysis of postoperative PSA changes after ultrasound-guided permanent [125I] seed implantation for the treatment of prostate cancer.

    PubMed

    Bian, X L; Wang, C Z; Wang, Y; Li, Y N; Zhang, L Z; Liu, L

    2015-01-01

    The aim of this study was to explore postoperative changes in prostate-specific antigen (PSA) levels and risk factors that influence the clinical effects of ultrasound-guided permanent [(125)I] seed implantation in the treatment of prostate cancer. From July 2009 to December 2012, 41 prostate cancer patients who underwent transrectal ultrasound-guided [(125)I] seed implantation were followed up for 3-56 months. The patients were divided into 2 groups according to their results: group A, benign rebound group, 31 cases; and group B, biochemical relapse group, 10 cases. A blood analysis of group A showed that the initial PSA rise after a nadir occurred postoperatively at 16.8 ± 1.2 months, and in 65.8% (27/41) patients the rise occurred during 15-27 weeks. For group B, the initial PSA rise after a nadir occurred postoperatively at 30.2 ± 2.1 months, and the difference in the time parameter of the initial PSA rise after the nadir was statistically significant between the 2 groups (P < 0.01). During treatment, age was shown to be a risk factor for group A (P = 0.0027, P < 0.01). Postoperative changes in PSA levels after ultrasound-guided permanent [(125)I] seed implantation contributed to the assessment of the clinical treatment effects. PMID:26125925

  18. [Comparison of Tandem-R PSA and Markit-M PA in the diagnosis of prostate cancer].

    PubMed

    Okegawa, T; Kato, M; Miyata, A; Murata, A; Miura, I; Yoneda, T; Nutahara, K; Higashihara, E

    1999-03-01

    The Tandem-R PSA (TR) assay was compared with the Markit-M PA (MM) assay in the diagnosis of the prostate cancer. In patients with a serum prostate specific antigen (PSA) level higher than the cut-off values measured by either the TR assay or the MM assay (4.1 ng/ml and 3.7 ng/ml, respectively), or a suspicious digital rectal examination, sextant biopsy of the prostate was performed. Among 227 patients undergoing biopsy, 64 patients were diagnosed as having prostate cancer. There was a significant difference of serum PSA values between patients with and without prostate cancer in either assay. There was no significant difference between the assays with respect to diagnosing according to prostate cancer using receiver operating characteristic analysis. The correlation between TR and MM in 150 men with a serum Tandem-R PSA below 10 ng/ml was Y = 1.12X + 3.745 (R = 0.68, p < 0.001). The correlation coefficient for the relationship between TR and MM was only 0.68, indicating a poor correlation. Four of the 15 patients with MM values below 4.0 ng/ml calculated by transformation from MM to TR values had prostate cancer. This suggested that conversion of MM values to TR values in the low PSA range presents problems. PMID:10331169

  19. Mechanisms and factors affecting the adsorption of sodium alginate onto modified clays

    NASA Astrophysics Data System (ADS)

    Lin, Yongxin; Cao, Xihua; Song, Xiuxian; Wang, Nan; Yu, Zhiming

    2013-07-01

    Algal organic materials (AOMs) are one critical factor affecting the efficiency of modified clays used for the mitigation of harmful algal blooms (HABs). This study was conducted to develop a deeper understanding of the mechanisms and factors affecting the adsorption of AOMs onto modified clays. Sodium alginate (polysaccharide) and kaolinite modified with polyaluminium chloride (PACl) were used as AOMs and modified clay model substances, respectively, and the effects of modifier dosage, contact time, solution pH and ionic strength were investigated through batch adsorption experiments. Kinetics revealed that the alginate adsorption rate was described well by a pseudo-second order model. PACl effectively enhanced the adsorption capacity of kaolinite and increased the adsorption rate, and the optimum additive amount of PACl was 5%. The experimental data fitted both the Freundlich and Langmuir adsorption equations well. The adsorption thermodynamics for alginate onto modified clays suggests that alginate adsorption is a spontaneous process. The adsorption of alginate onto modified clays was highly dependent on pH, with a decrease in adsorption observed with increased pH to 9.48, but the opposite was true above pH 9.48. Finally, adsorption increased with increasing ionic strength.

  20. [Application of classical isothermal adsorption models in heavy metal ions/ diatomite system and related problems].

    PubMed

    Zhu, Jian; Wu, Qing-Ding; Wang, Ping; Li, Ke-Lin; Lei, Ming-Jing; Zhang, Wei-Li

    2013-11-01

    In order to fully understand adsorption nature of Cu2+, Zn2+, Pb2+, Cd2+, Mn2+, Fe3+ onto natural diatomite, and to find problems of classical isothermal adsorption models' application in liquid/solid system, a series of isothermal adsorption tests were conducted. As results indicate, the most suitable isotherm models for describing adsorption of Pb2+, Cd2+, Cu2+, Zn2+, Mn2+, Fe3+ onto natural diatomite are Tenkin, Tenkin, Langmuir, Tenkin, Freundlich and Freundlich, respectively, the adsorption of each ion onto natural diatomite is mainly a physical process, and the adsorption reaction is favorable. It also can be found that, when using classical isothermal adsorption models to fit the experimental data in liquid/solid system, the equilibrium adsorption amount q(e) is not a single function of ion equilibrium concentration c(e), while is a function of two variables, namely c(e) and the adsorbent concentration W0, q(e) only depends on c(e)/W(0). Results also show that the classical isothermal adsorption models have a significant adsorbent effect, and their parameter values are unstable, the simulation values of parameter differ greatly from the measured values, which is unhelpful for practical use. The tests prove that four-adsorption-components model can be used for describing adsorption behavior of single ion in nature diatomite-liquid system, its parameters k and q(m) have constant values, which is favorable for practical quantitative calculation in a given system. PMID:24455943

  1. Adsorption kinetics of benzotriazole and its derivatives by nano Zn-Al-O.

    PubMed

    Xu, Bingbing; Qi, Fei; Wu, Fengchang; Xu, Qiujin; Chen, Zhonglin

    2014-09-01

    Benzotriazole and its derivatives are important industrial auxiliaries, which are serious pollution sources in the natural aquatic environment. Benzotriazole and its derivatives adsorption by a novel nano absorbent (nano Zn-Al-O binary metal oxide, named as ZAO) being explored as an effective water treatment method, was carried out in this study. Results showed that benzotriazole and its derivatives were all effectively adsorbed from water by ZAO. Removal efficiencies of benzotriazole, 5-methyl-benzotriazol and 5,6-dimethyl-benzotriazole with 5 g/L adsorbent dosage achieved 89%, 81% and 92%, respectively. The adsorption kinetics and isotherm models were used to express the adsorption process and discuss the adsorption mechanism. The adsorption kinetics well followed pseudo-second-order model, indicating that chemical adsorption dominated the adsorption. Adsorption isotherm was well expressed by Freundlich model. Structure characteristics of benzotriazole and its derivatives had great effect on their adsorption. Hydrogen-bond interaction was considered as the main mechanism for the surface adsorption. However, hydrophobic interactions played an important role in 5,6-dimethyl-benzotriazole adsorption due to its weak polarity. PMID:25924402

  2. Preparation of titanium peroxide and its selective adsorption property on cationic dyes

    NASA Astrophysics Data System (ADS)

    Zhao, Xiao-guang; Huang, Ji-guo; Wang, Bo; Bi, Qiang; Dong, Li-li; Liu, Xing-juan

    2014-02-01

    Titanium peroxide powder was prepared with the reaction of titanium sulfate and H2O2 and showed good selective adsorption property on cationic dyes. The obtained material was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric and differential scanning calorimetry (TG-DSC). The selective adsorption property was confirmed and evaluated by adsorption experiments of methyl orange (MO), phenol and three kinds of cationic dyes including methylene blue (MB), malachite green (MG) and neutral red (NR). The adsorption was very fast and adsorption equilibrium was reached in a very short time for all three cationic dyes. The adsorption kinetics of MB, MG and NR were studied then. It was found that the adsorption data fitted perfectly with the pseudo-second-order kinetics and the saturated adsorption capacities for MB, MG and NR were 224.37, 251.38 and 327.61 mg/g at 25 °C, respectively. The characterization and adsorption results indicated the controlling mechanism of adsorption processes could be electrostatic adsorption.

  3. The effects of CO{sub 2} on steam adsorption

    SciTech Connect

    Palar, Steve; Horne, Roland N.

    1994-01-20

    Water adsorption in geothermal reservoir materials was investigated by transient flow technique using steam and COz gas. Theoretical and experimental results indicate that water adsorption exists in vapordominated type of reservoir, but experiments in the past have been limited to pure gases. The common presence of CO2, a non-condensible gas, in a geothermal reservoir necessitated a study of the effect of partial CO2 concentration on adsorption. Experimental laboratory work using a crushed Geysers rock sample at low pressure was carried out. Transient pressure exerted by steam pressure inside the sample was measured against time during a desorption process. It was found that the partial presence of CO2 did not significantly affect the adsorption of water.

  4. Coulometric study of ethanol adsorption at a polycrystalline platinum electrode

    NASA Astrophysics Data System (ADS)

    Gilman, Sol

    2012-01-01

    For the first time, use of a novel pre-conditioning sequence and measurements of hydrogen blockage during fast cathodic scans has enabled the determination of rates of accumulation of ethanolic species on the surface of a platinum electrode under well-controlled conditions of surface cleanliness/activity and mass transport. For dilute solutions of ethanol in 1 N perchloric acid (HClO4), oxidative adsorption rates maximize at 0.3 V, drop off at more cathodic potentials due to competition with adsorbed hydrogen and drop off at more anodic potentials due to oxidative processes that produce products released to the electrolyte. The time and concentration dependence of adsorption follows relationships that are common for adsorption on a heterogeneous surface. Some evidence are presented supporting a mechanism for production of soluble products that does not involve the adsorbed species that are detected through the measurement of blockage of hydrogen adsorption sites.

  5. Centrif