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Sample records for adsorption psa unit

  1. 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.

  2. Possibility of using adsorption refrigeration unit in district heating network

    NASA Astrophysics Data System (ADS)

    Grzebielec, Andrzej; Rusowicz, Artur; Jaworski, Maciej; Laskowski, Rafał

    2015-09-01

    Adsorption refrigeration systems are able to work with heat sources of temperature starting with 50 °C. The aim of the article is to determine whether in terms of technical and economic issues adsorption refrigeration equipment can work as elements that produce cold using hot water from the district heating network. For this purpose, examined was the work of the adsorption air conditioning equipment cooperating with drycooler, and the opportunities offered by the district heating network in Warsaw during the summer. It turns out that the efficiency of the adsorption device from the economic perspective is not sufficient for production of cold even during the transitional period. The main problem is not the low temperature of the water supply, but the large difference between the coefficients of performance, COPs, of adsorption device and a traditional compressor air conditioning unit. When outside air temperature is 25 °C, the COP of the compressor type reaches a value of 4.49, whereas that of the adsorption device in the same conditions is 0.14. The ratio of the COPs is 32. At the same time ratio between the price of 1 kWh of electric power and 1 kWh of heat is only 2.85. Adsorption refrigeration equipment to be able to compete with compressor devices, should feature COPads efficiency to be greater than 1.52. At such a low driving temperature and even changing the drycooler into the evaporative cooler it is not currently possible to achieve.

  3. 76 FR 82323 - Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-30

    ....'' This guide applies to the design, inspection, and testing of air filtration and iodine adsorption units... the design, inspection, and testing of air filtration and iodine adsorption units of...

  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. 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.

  6. 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.

  7. A Sixth-Form Teaching Unit on the Langmuir Adsorption Isotherm

    ERIC Educational Resources Information Center

    Walkley, G. H.

    1973-01-01

    Presents a teaching unit on the Langmuir absorption isotherm suitable for advanced secondary school chemistry classes. Describes the experimental investigation of the isothermal adsorption of sulfur dioxide on charcoal, and discusses the derivation of the Langmuir equation and some applications. (JR)

  8. 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

  9. Adsorption of Carbon Tetrachloride to Sediments from the UP-1 Operable Unit

    SciTech Connect

    Wellman, Dawn M.; Riley, Robert G.; Parker, Kent E.; Mitroshkov, Alexandre V.

    2006-09-01

    In 2004, Fluor Hanford, Inc. (FHI) drilled several groundwater wells within the 200-UP-1 operable unit to monitor plumes that have been the focus of past remediation activities. Thirteen cores taken from three wells (C4298, C4299, and C4300) were sent to Pacific Northwest National Laboratory for characterization and quantification of contaminant retardation. These cores were 4-inches in diameter by 6-inches in length and were taken from depths near the unconfined aquifer surface (water table) to locations approximately 150 to 180 ft below the water table. Prior to this work, no 200-UP-1 site-specific adsorption data (i.e., values of distribution coefficient [Kd ]) were available for the sediments or key contaminants present in the 200-UP-1 operable unit groundwater plume. Site-specific sorption data for carbon tetrachloride (CCl4) was obtained with the <2 mm size fractions of uncontaminated 200-UP-1 sediments taken from two of these boreholes (C4299 and C4300) and distribution coefficients determined. Each fraction exhibited bimodal CCl4 adsorption isotherms over the concentration range (15 – 2500 μg L-1) for total CCl4 in solution. Sorption of CCl4 was linear over the concentration ranges of 15 to 400 μg L-1 and 400 to 2500 μg L-1. The Kd values measured for the three 200-UP-1 sediments exhibited bimodal sorption with initial Kd values ranging from 0.0002 to 0.0005, and phase 2 values approximately 0.003 for all sediments. The measure Kd values are lower than the range calculated for CCl4 in a Hanford soil (0.016 to 0.83 L/Kg) containing an average organic carbon content of 0.2% (Truex et al., 2001). The best estimate value of Truex et al. (2001) is 0.06 L/Kg based on a 0.1% sediment organic carbon content. However, this estimate is based on an organic carbon content up to an order of magnitude greater than the organic carbon content of the sediments tested herein. Prolonged contact may increase

  10. Testing and Results of Vacuum Swing Adsorption Units for Spacesuit Carbon Dioxide and Humidity Control

    NASA Technical Reports Server (NTRS)

    McMillin, Summer; Broerman, Craig; Swickrath, Mike; Anderson, Molly

    2010-01-01

    A principal concern for extravehicular activity (EVA) space suits is the capability to control carbon dioxide (CO2) and humidity (H2O) for the crewmember. The release of CO2 in a confined or unventilated area is dangerous for human health and leads to asphyxiation; therefore, CO2 and H2O become leading factors in the design and development of the spacesuit. An amine-based CO2 and H2O vapor sorbent for use in pressure-swing re-generable beds has been developed by Hamilton Sundstrand. The application of solid-amine materials with vacuum swing adsorption technology has shown the capacity to concurrently manage CO2 and H2O levels through a fully regenerative cycle eliminating mission constraints imposed with non-regenerative technologies. Two prototype solid amine-based systems, known as rapid cycle amine (RCA), were designed to continuously remove CO2 and H2O vapor from a flowing ventilation stream through the use of a two-bed amine based, vacuum-swing adsorption system. The Engineering and Science Contract Group (ESCG) RCA is the first RCA unit implementing radial flow paths, whereas the Hamilton Sundstrand RCA was designed with linear flow paths. Testing was performed in a sea-level pressure environment and a reduced-pressure environment with simulated human metabolic loads in a closed-loop configuration. This paper presents the experimental results of laboratory testing for a full-size and a sub-scale test article. The testing described here characterized and evaluated the performance of each RCA unit at the required Portable Life Support Subsystem (PLSS) operating conditions. The test points simulated a range of crewmember metabolic rates. The experimental results demonstrate the ability of each RCA unit to sufficiently remove CO2 and H2O from a closed loop ambient or subambient atmosphere.

  11. Testing and Results of Vacuum Swing Adsorption Units for Spacesuit Carbon Dioxide and Humidity Control

    NASA Technical Reports Server (NTRS)

    McMillin, Summer D.; Broerman, Craig D.; Swickrath, Michael; Anderson, Molly

    2011-01-01

    A principal concern for extravehicular activity (EVA) spacesuits is the capability to control carbon dioxide (CO2) and humidity (H2O) for the crewmember. The release of CO2 in a confined or unventilated area is dangerous for human health and leads to asphyxiation; therefore, CO2 and H2O control become leading factors in the design and development of the spacesuit. An amine-based CO2 and H2O vapor sorbent for use in pressure-swing regenerable beds has been developed by Hamilton Sundstrand. The application of solidamine materials with vacuum swing adsorption technology has shown the capacity to concurrently manage CO2 and H2O levels through a fully regenerative cycle eliminating mission constraints imposed with nonregenerative technologies. Two prototype solid amine-based systems, known as rapid cycle amine (RCA), were designed to continuously remove CO2 and H2O vapor from a flowing ventilation stream through the use of a two-bed amine based, vacuum-swing adsorption system. The Engineering and Science Contract Group (ESCG) RCA implements radial flow paths, whereas the Hamilton Sundstrand RCA was designed with linear flow paths. Testing was performed in a sea-level pressure environment and a reduced-pressure environment with simulated human metabolic loads in a closed-loop configuration. This paper presents the experimental results of laboratory testing for a full-size and a sub-scale test article. The testing described here characterized and evaluated the performance of each RCA unit at the required Portable Life Support Subsystem (PLSS) operating conditions. The test points simulated a range of crewmember metabolic rates. The experimental results demonstrated the ability of each RCA unit to sufficiently remove CO2 and H2O from a closed loop ambient or sub-ambient atmosphere.

  12. 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.

  13. Understanding adsorption-induced structural transitions in metal-organic frameworks: From the unit cell to the crystal

    NASA Astrophysics Data System (ADS)

    Triguero, Carles; Coudert, François-Xavier; Boutin, Anne; Fuchs, Alain H.; Neimark, Alexander V.

    2012-11-01

    Breathing transitions represent recently discovered adsorption-induced structural transformations between large-pore and narrow-pore conformations in bi-stable metal-organic frameworks such as MIL-53. We present a multiscale physical mechanism of the dynamics of breathing transitions. We show that due to interplay between host framework elasticity and guest molecule adsorption, these transformations on the crystal level occur via layer-by-layer shear. We construct a simple Hamiltonian that describes the physics of host-host and host-guest interactions on the level of unit cells and reduces to one effective dimension due to the long-range elastic cell-cell interactions. We then use this Hamiltonian in Monte Carlo simulations of adsorption-desorption cycles to study how the behavior of unit cells is linked to the transition mechanism at the crystal level through three key physical parameters: the transition energy barrier, the cell-cell elastic coupling, and the system size.

  14. The PSA: Planetary Science Archive

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

  15. The PSA: Planetary Science Archive

    NASA Astrophysics Data System (ADS)

    Barthelemy, 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

  16. 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)

  17. 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

  18. Experimental tests and predictive model of an adsorptive air conditioning unit

    SciTech Connect

    Poyelle, F.; Guilleminot, J.J.; Meunier, F.

    1999-01-01

    An adsorption air conditioning unit has been built operating with a heat nd mass recovery cycle and a zeolite-water pair. A new consolidated adsorbent composite with good heat transfer properties has been developed and implemented in the adsorber. At an evaporating temperature of 4 C, the experimental specific cooling power (SCP) of 97 W/kg achieved represents a real improvement in comparison with those measured with a packed bed technology. At this evaporating pressure, the mass transfer resistance controls the process. Therefore, at higher evaporating temperature a COP of 0.68 and a SCP of 135 W/kg were experimentally achieved. A new model has been developed to take into account the mass transfer limitations. The model has been validated and can predict the average pressure inside the adsorber and the components temperature of the unit. A new high conductive material with enhanced mass transfer properties has been developed. The predictive model shows that a SCP of 600 W/kg and a COP of 0.74 could be achieved with this new material.

  19. Simulation and Optimization of Vacuum Swing Adsorption Units for Spacesuit Carbon Dioxide and Humidity Control

    NASA Technical Reports Server (NTRS)

    Swickrath, Michael J.; Anderson, Molly; McMillin, Summer; Broerman, Craig

    2010-01-01

    Controlling carbon dioxide (CO2) and humidity levels in a spacesuit is critical to ensuring both the safety and comfort of an astronaut during extra-vehicular activity (EVA). Traditionally, this has been accomplished utilizing non-regenerative lithium hydroxide (LiOH) or regenerative metal oxide (MetOx) canisters which pose a significant weight burden. Although such technology enables air revitalization, the volume requirements to store the waste canisters as well as the mass to transport multiple units become prohibitive as mission durations increase. Consequently, motivation exists toward developing a fully regenerative technology for environmental control. The application of solid amine materials with vacuum swing adsorption technology has shown the capacity to control CO2 and concomitantly manage humidity levels through a fully regenerative cycle eliminating mission constraints imposed with non-regenerative technologies. Experimental results for full-size and sub-scale test articles have been collected and are described herein. In order to accelerate the developmental efforts, an axially-dispersed plug ow model with an accompanying energy balance has been established and correlated with the experimental data. The experimental and simulation results display good agreement for a variety of ow rates (110-170 SLM), replicated metabolic challenges (100-590 Watts), and atmosphere pressures under consideration for the spacesuit (248 and 760 mm Hg). The relationship between swing adsorption cycles for an outlet criterion of 6.0 mm Hg of CO2 partial pressure has been established for each metabolic challenge. In addition, variable metabolic profiles were imposed on the test articles in order to assess the ability of the technology to transition to new operational constraints. The advent of the model provides the capacity to apply computer-aided engineering practices to support the ongoing efforts to optimize and mature this technology for future application to space

  20. Experimental results and modeling tests of an adsorptive air-conditioning unit

    SciTech Connect

    Guilleminot, J.J.; Poyelle, F.; Meunier, F.

    1998-10-01

    Experimental tests have been performed on a zeolite-water adsorptive system suitable for air conditioning and consisting of two adsorbers filled with a consolidated composite made of zeolite mixed with a highly conductive matrix. This paper describes the experimental results of such a heat pump unit operating with a heat and mass recovery cycle. An important enhancement of the specific cooling power (SCP) has been achieved. At evaporating temperature T = 4 C, mass transfer resistance controls the process and limits the expected COP. Tests carried out at higher evaporating pressure make it possible to achieve the predicted COP and SCP. A predictive model developed and validated elsewhere in order to describe the temperature evolution of components and the heat and mass transfer in the adsorbers explains the mass transfer resistance in the adsorbent. Last, a new highly conductive adsorbent composite with good mass transfer properties is developed. The model is used to predict the performances of this new material. Very good SCP and COP can be achieved.

  1. Simulation and Optimization of Vacuum Swing Adsorption Units for Spacesuit Carbon Dioxide and Humidity Control

    NASA Technical Reports Server (NTRS)

    Swickrath, Michael J.; Anderson, Molly; McMillin, Summer; Broerman, Craig

    2011-01-01

    Controlling carbon dioxide (CO2) and humidity levels in a spacesuit is critical to ensuring both the safety and comfort of an astronaut during extra-vehicular activity (EVA). Traditionally, this has been accomplished utilizing either non-regenerative lithium hydroxide (LiOH) or regenerative but heavy metal oxide (MetOx) canisters which pose a significant weight burden. Although such technology enables air revitalization, the volume requirements to store the waste canisters as well as the mass to transport multiple units become prohibitive as mission durations increase. Consequently, motivation exists toward developing a fully regenerative technology for spacesuit environmental control. The application of solid amine materials with vacuum swing adsorption technology has shown the capacity to control CO2 while concomitantly managing humidity levels through a fully regenerative cycle eliminating constraints imposed with the traditional technologies. Prototype air revitalization units employing this technology have been fabricated in both a rectangular and cylindrical geometry. Experimental results for these test articles have been collected and are described herein. In order to accelerate the developmental efforts, an axially-dispersed plug flow model with an accompanying energy balance has been established and correlated with the experimental data. The experimental and simulation results display good agreement for a variety of flow rates (110-170 ALM), replicated metabolic challenges (100-590 Watts), and atmosphere pressures under consideration for the spacesuit (248 and 760 mm Hg). The testing and model results lend insight into the operational capabilities of these devices as well as the influence the geometry of the device has on performance. In addition, variable metabolic profiles were imposed on the test articles in order to assess the ability of the technology to transition to new metabolic conditions. The advent of the model provides the capacity to apply

  2. [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.

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

    PubMed

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

    2013-01-01

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

  5. Prostate-specific antigen (PSA) blood test

    MedlinePlus

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

  6. 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.

  7. Expanded Porous Metal-Organic Frameworks by SCSC: Organic Building Units Modifying and Enhanced Gas-Adsorption Properties.

    PubMed

    Fan, Weidong; Lin, Huan; Yuan, Xue; Dai, Fangna; Xiao, Zhenyu; Zhang, Liangliang; Luo, Liwen; Wang, Rongming

    2016-07-01

    Two amino-functional copper metal-organic frameworks of formula [Cu3(ATTCA)2(H2O)3]·2DMF·11H2O·12EtOH (1) (H3ATTCA = 2-amino-[1,1:3,1-terphenyl]-4,4,5-tricarboxylic acid, pyz = pyrazine, DMF = dimethylformamide) and [Cu3(ATTCA)2(pyz)(H2O)]·2DMF·12H2O·8EtOH (2) were synthesized under solvothermal conditions and characterized by single-crystal X-ray diffraction, infrared spectroscopy, elemental analyses, thermogravimetric analyses, and powder X-ray diffraction. Single-crystal X-ray diffraction analysis revealed that both complexes 1 and 2 are built of the Cu2(COO)4 paddlewheel secondary building units with an fmj topology. Importantly, complex 1 can be transformed into complex 2 by the single-crystal to single-crystal transformation of which the coordinated water molecules are replaced with pyz molecules. However, the adsorption abilities of 2 are obviously lower than those of 1, as its pores are partially blocked by pyz molecules. Moreover, gas-adsorption analysis showed that the amino-functional 1 possesses higher gas-adsorption capacity than UMCM-151 for N2, H2, CH4, and C2H2, especially for CO2. PMID:27315443

  8. 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

  9. 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 ...

  10. Intra- and inter-unit variation in fly ash petrography and mercury adsorption: Examples from a western Kentucky power station

    USGS Publications Warehouse

    Hower, J.C.; Finkelman, R.B.; Rathbone, R.F.; Goodman, J.

    2000-01-01

    Fly ash was collected from eight mechanical and 10 baghouse hoppers at each of the twin 150-MW wall-fired units in a western Kentucky power station. The fuel burned at that time was a blend of many low-sulfur, high-volatile bituminous Central Appalachian coals. The baghouse ash showed less variation between units than the mechanical hoppers. The mechanical fly ash, coarser than the baghouse ash, showed significant differences in the amount of total carbon and in the ratio of isotropic coke to both total carbon and total coke - the latter excluding inertinite and other unburned, uncoked coal. There was no significant variation in proportions of inorganic fly ash constituents. The inter-unit differences in the amount and forms of mechanical fly ash carbon appear to be related to differences in pulverizer efficiency, leading to greater amounts of coarse coal, therefore unburned carbon, in one of the units. Mercury capture is a function of both the total carbon content and the gas temperature at the point of fly ash separation, mercury content increasing with an increase in carbon for a specific collection system. Mercury adsorption on fly ash carbon increases at lower flue-gas temperatures. Baghouse fly ash, collected at a lower temperature than the higher-carbon mechanically separated fly ash, contains a significantly greater amount of Hg.

  11. 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

  12. 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.

  13. Integrated Testing of a 4-Bed Molecular Sieve, Air-Cooled Temperature Swing Adsorption Compressor, and Sabatier Engineering Development Unit

    NASA Technical Reports Server (NTRS)

    Knox, James C.; Miller, Lee; Campbell, Melissa; Mulloth, Lila; Varghese, Mini

    2006-01-01

    Accumulation and subsequent compression of carbon dioxide that is removed from the space cabin are two important processes involved in a closed-loop air revitalization scheme of the International Space Station (ISS). The 4-Bed Molecular Sieve (4BMS) of ISS currently operates in an open loop mode without a compressor. The Sabatier Engineering Development Unit (EDU) processes waste CO2 to provide water to the crew. This paper reports the integrated 4BMS, air-cooled Temperature Swing Adsorption Compressor (TSAC), and Sabatier EDU testing. The TSAC prototype was developed at NASA Ames Research Center (ARC). The 4BMS was modified to a functionally flight-like condition at NASA Marshall Space Flight Center (MSFC). Testing was conducted at MSFC. The paper provides details of the TSAC operation at various CO2 loadings and corresponding performance of the 4BMS and Sabatier.

  14. Design and Assembly of an Integrated Metabolic Heat Regenerated Temperature Swing Adsorption (MTSA) Subassembly Engineering Development Unit

    NASA Technical Reports Server (NTRS)

    Padilla, Sebastian A.; Powers, Aaron; Iacomini, Christie S.; Bower, Chad E.; Paul, Heather L.

    2012-01-01

    Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal and carbon dioxide (CO2) control for a Portable Life Support System (PLSS), as well as water recycling. The core of the MTSA technology is a sorbent bed that removes CO2 from the PLSS ventilation loop gas via a temperature swing. A Condensing Icing Heat eXchanger (CIHX) is used to warm the sorbent while also removing water from the ventilation loop gas. A Sublimation Heat eXchanger (SHX) is used to cool the sorbent. Research was performed to explore an MTSA designed for both lunar and Martian operations. Previously the sorbent bed, CIHX, and SHX had been built and tested individually on a scale relevant to PLSS operations, but they had not been done so as an integrated subassembly. Design and analysis of an integrated subassembly was performed based on this prior experience and an updated transient system model. Focus was on optimizing the design for Martian operations, but the design can also be used in lunar operations. An Engineering Development Unit (EDU) of an integrated MTSA subassembly was assembled based on the design. Its fabrication is discussed. Some details on the differences between the as-assembled EDU and the future flight unit are considered.

  15. Design and Assembly of an Integrated Metabolic Heat Regenerated Temperature Swing Adsorption (MTSA) Subassembly Engineering Development Unit

    NASA Technical Reports Server (NTRS)

    Padilla, Sebastian A.; Powers, Aaron; Iacomini, Christie S.; Paul, Heather L.

    2011-01-01

    Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal and carbon dioxide (CO2) control for a Portable Life Support System (PLSS), as well as water recycling. The core of the MTSA technology is a sorbent bed that removes CO2 from the PLSS ventilation loop gas via a temperature swing. A Condensing Ice Heat eXchanger (CIHX) is used to warm the sorbent while also removing water from the ventilation loop gas. A Sublimation Heat eXchanger (SHX) is used to cool the sorbent. Research was performed to explore an MTSA designed for both lunar and Martian operations. Previously each the sorbent bed, CIHX, and SHX had been built and tested individually on a scale relevant to PLSS operations, but they had not been done so as an integrated subassembly. Design and analysis of an integrated subassembly was performed based on this prior experience and an updated transient system model. Focus was on optimizing the design for Martian operations, but the design can also be used in lunar operations. An Engineering Development Unit (EDU) of an integrated MTSA subassembly was assembled based on the design. Its fabrication is discussed. Some details on the differences between the as-assembled EDU to the future flight unit are considered.

  16. 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.

  17. 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

  18. PSA-operations synergism for the advanced test reactor shutdown operations PSA

    SciTech Connect

    Atkinson, S.A.

    1996-08-01

    The Advanced Test Reactor (ATR) Probabilistic Safety Assessment (PSA) for shutdown operations, cask handling, and canal draining is a successful example of the importance of good PSA-operations synergism for achieving a realistic and accepted assessment of the risks and for achieving desired risk reduction and safety improvement in a best and cost-effective manner. The implementation of the agreed-upon upgrades and improvements resulted in the reductions of the estimated mean frequency for core or canal irradiated fuel uncovery events, a total reduction in risk by a factor of nearly 1000 to a very low and acceptable risk level for potentially severe events.

  19. 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.

  20. 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.

  1. 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

  2. A Comparative Performance Analysis of Total PSA, Percentage Free PSA, PSA Velocity, and PSA Density versus the Detection of Primary Circulating Prostate Cells in Predicting Initial Prostate Biopsy Findings in Chilean Men

    PubMed Central

    Murray, Nigel P.; Reyes, Eduardo; Orellana, Nelson; Fuentealba, Cynthia; Dueñas, Ricardo

    2014-01-01

    Introduction. PSA parameters have been used in an attempt to improve the diagnostic yield of prostate screening tests; the detection of primary malignant circulating prostate cells (CPCs) may improve the diagnostic yield of screening and therefore avoid unnecessary biopsies. Patients and Methods. Prospective study of all men undergoing initial prostate biopsy due to an elevated total serum PSA. Free percent PSA, PSA velocity, and PSA density were determined. Primary CPCs were detected using standard immunocytochemistry. A positive test for CPCs was defined as one cell PSA (+) P504S (+) in an 8 ml blood sample. Positive predictive and negative predictive values, specificity, and sensitivity were calculated for each test as well as the number of biopsies avoided and cancers missed. Results. 303 men participated in the study of whom 113/303 (37.3%) men had prostate cancer. Of the three PSA based parameters, free percent PSA was superior, sensitivity 70.8%, and specificity 67.4%. Primary CPCs detection had a sensitivity of 88.5% and a specificity of 88.4% avoiding 181 (59.7%) biopsies, detecting 93/95 (98%) of clinically significant cancers, and missing 13 (11.5%) low grade, small volume tumors. Conclusions. The use of primary CPCs as a sequential test could decrease the number of initial prostate biopsies missing those cancers which are treated by active observation. PMID:25101294

  3. 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

  4. Ab Initio Study of the Adsorption of Small Molecules on Metal-Organic Frameworks with Oxo-centered Trimetallic Building Units: The Role of the Undercoordinated Metal Ion.

    PubMed

    Mavrandonakis, Andreas; Vogiatzis, Konstantinos D; Boese, A Daniel; Fink, Karin; Heine, Thomas; Klopper, Wim

    2015-09-01

    The interactions of H2, CO, CO2, and H2O with the undercoordinated metal centers of the trimetallic oxo-centered M3(III)(μ3-O)(X) (COO)6 moiety are studied by means of wave function and density functional theory. This trimetallic oxo-centered cluster is a common building unit in several metal-organic frameworks (MOFs) such as MIL-100, MIL-101, and MIL-127 (also referred to as soc-MOF). A combinatorial computational screening is performed for a large variety of trimetallic oxo-centered units M3(III)O (M = Al(3+), Sc(3+), V(3+), Cr(3+), Fe(3+), Ga(3+), Rh(3+), In(3+), Ir(3+)) interacting with H2O, H2, CO, and CO2. The screening addresses interaction energies, adsorption enthalpies, and vibrational properties. The results show that the Rh and Ir analogues are very promising materials for gas storage and separations.

  5. 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

  6. Impact of assay parameters on the accuracy of free PSA test: source and stability of calibrator, calibration curve fitting, and level of total PSA in the serum.

    PubMed

    Liu, G H; Wu, J T

    1998-01-01

    The measurement of PSA is recommended for men over 50 years of age for screening of prostate cancer. However, proper differentiation of prostate cancer from benign prostate hyperplasia (BPH) relies on an accurate measurement of free PSA (fPSA) and a correct calculation of percent fPSA. Because of the extremely low concentration of fPSA in the serum, any slight deviation from its true value may produce large errors in percent fPSA calculated. Therefore, we undertook a study examining carefully those parameters of the fPSA assay which might affect the fPSA determination. We found that the integrity of the calibrator, the computer curve-fitting program selected, the source of the calibrator, and the total PSA or fPSA + PSA complexes (tPSA) concentration of the specimen all had an impact on the accuracy of the fPSA value assayed. We found that an examination of the slope of the calibration curve was important to reveal whether the calibrator had or had not been denatured during storage. We also found that the 4-parameter cure fitting program was best suited for plotting the fPSA calibration curve. The calibrator we isolated from LNCaP cells was acceptable for our assay because it had an affinity for the assay antibody very similar to that of serum fPSA. We also determined the effect of tPSA concentration on the fPSA determinations and found that within the concentration range of 4-10 ng/mL the impact on the percent fPSA calculated was not significant. We believe that our assay produces accurate fPSA values when all these assay parameters are well controlled.

  7. 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.

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

    PubMed

    Defilippi, Elio; Zitella, Andrea; Tizzani, Alessandro

    2011-01-01

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

  9. 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.

  10. 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.

  11. The precursor of PsaD assembles into the photosystem I complex in two steps.

    PubMed Central

    Minai, L; Cohen, Y; Chitnis, P R; Nechushtai, R

    1996-01-01

    The present study addresses the assembly in the chloroplast thylakoid membranes of PsaD, a peripheral membrane protein of the photosystem I complex. Located on the stromal side of the thylakoids, PsaD was found to assemble in vitro into the membranes in its precursor (pre-PsaD) and also in its mature (PsaD) form. Newly assembled unprocessed pre-PsaD was resistant to NaBr and alkaline wash. Yet it was sensitive to proteolytic digestion. In contradistinction, when the assembled precursor was processed, the resulting mature PsaD was resistant to proteases to the same extent as endogenous [correction of endogeneous] PsaD. The accumulation of protease-resistant PsaD in the thylakoids correlated with the increase of mature-PsaD in the membranes. This protection of mature PsaD from proteolysis could not be observed when PsaD was in a soluble form-i.e. not assembled within the thylakoids. The data suggest that pre-PsaD assembles to the membranes and only in a second step processing takes place. The observation that the assembly of pre-PsaD is affected by salts to a much lesser extent than that of mature-PsaD supports a two-step assembly of pre-PsaD. Images Fig. 1 Fig. 2 Fig. 4 Fig. 5 PMID:8692816

  12. Performance Characterization and Simulation of Amine-Based Vacuum Swing Adsorption Units for Spacesuit Carbon Dioxide and Humidity Control

    NASA Technical Reports Server (NTRS)

    Swickrath, Michael J.; Watts,Carly; Anderson, Molly; McMillin, Summer; Boerman, Craig; Colunga, Aaron; Vogel, Matthew

    2011-01-01

    Controlling carbon dioxide (CO2) and water (H2O) concentrations in the vapor phase of a space suit is critical to ensuring an astronauts safety, comfortability, and capability to perform extra-vehicular activity (EVA) tasks. Historically, this has been accomplished using lithium hydroxide (LiOH) and metal oxides (MetOx). Lithium hydroxide is a consumable material and requires priming with water before it becomes effective at removing carbon dioxide. MetOx is regenerable through a power-intensive thermal cycle but is significantly heavier on a volume basis than LiOH. As an alternative, amine-based vacuum swing beds are under aggressive development for EVA applications which control atmospheric concentrations of both CO2 and H2O through a fully-regenerative process. The current concept, referred to as the rapid cycle amine (RCA), has resulted in numerous laboratory prototypes. Performance of these prototypes have been assessed and documented from experimental and theoretical perspectives. To support developmental efforts, a first principles model has also been established for the vacuum swing adsorption technology. The efforts documented herein summarize performance characterization and simulation results for several variable metabolic profiles subjected to the RCA. Furthermore, a variety of control methods are explored including timed swing cycles, instantaneous CO2 feedback control, and time-averaged CO2 feedback control. A variety of off-nominal tests are also explored including high/low suit temperatures, increasingly high humidity cases, and dynamic pressure cases simulating the suit pre-breathe protocol. Consequently, this work builds on efforts previous efforts to fully bound the performance of the rapid cycle amine under a variety of nominal and off-nominal conditions.

  13. [Component analysis of the circulating fluid in an adsorption tower in a P-xylene unit based on raman spectral decomposition].

    PubMed

    Wang, Bin; Dai, Lian-kui

    2015-02-01

    In order to achieve fast and accurate online analysis of the circulating fluid in an adsorption tower in a p-xylene unit, the Raman spectral analysis method is adopted. However, the Raman spectra of the pure components included in the circulating fluid overlap together, and the concentration of each component varies obviously, the present Raman analysis technology needs a large amount of training samples. Therefore, this paper applies Raman spectral decomposition method in component analysis of the circulating fluid. First of all, the Raman spectra of the pure components and the spectra of a few training samples must be measured, and baseline subtraction and mean normalization are applied to obtain pretreated Raman spectra. Then the characteristic wave number range, 680-880 cm(-1), is chosen, and the Raman spectral decomposition method is adopted, to get decomposition coefficients of each component for each training sample. Next, the mathematical model between coefficients and concentrations of each component are built based on all training samples. For a testing sample, the above spectral pretreatment and the spectral decomposition for the same wave number range is adopted, then the decomposition coefficients of each component can be obtained. Based on the built mathematical model, the concentrations of all components can be predicted. Experimental results show that the standard prediction errors for the concentration of toluene, ethylbenzene, p-xylene, m-xylene, o-xylene and p-diethylbenzene are 0.301%, 0.088%, 0.563%, 0.384%, 0.366% and 0.536% respectively. The above method provides a methodological basis for the online analysis of the circulating fluid in adsorption towers.

  14. Solvent vapor recovery by pressure swing adsorption. 3: Comparison of simulation with experiment for the butane-activated carbon system

    SciTech Connect

    Liu, J.; Holland, C.E.; Ritter, J.A.

    1999-06-01

    A fully predictive (no adjustable parameters), nonisothermal, multicomponent mathematical model was developed and used to simulate a pressure swing adsorption (PSA) process designed for the separation and recovery of concentrated butane vapor from nitrogen using BAX activated carbon. Nearly quantitative agreement with experiment was realized with this model over a wide range of process conditions, and for both the transient and periodic state process dynamics and the periodic state process performance. The model also verified some unique characteristics of this PSA process, and it revealed some of the subtleties associated with accurately simulating a PSA-solvent vapor recovery (SVR) process. These subtleties included the need to account for the adsorbate heat capacity and the temperature dependence of the gas-phase physical properties. No PSA models in the literature have included both of these features, which were critical to the accurate prediction of the heat effects in this PSA-SVR process.

  15. 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

  16. 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)

  17. 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.

  18. 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

  19. 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…

  20. 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.

  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. Polymer adsorption

    NASA Astrophysics Data System (ADS)

    Joanny, Jean-Francois

    2008-03-01

    The aim of this talk is to review Pierre-Gilles deGennes' work on polymer adsorption and the impact that it has now in our understanding of this problem. We will first present the self-consistent mean-field theory and its applications to adsorption and depletion. De Gennes most important contribution is probably the derivation of the self-similar power law density profile for adsorbed polymer layers that we will present next, emphasizing the differences between the tail sections and the loop sections of the adsorbed polymers. We will then discuss the kinetics of polymer adsorption and the penetration of a new polymer chain in an adsobed layer that DeGennes described very elegantly in analogy with a quantum tunneling problem. Finally, we will discuss the role of polymer adsorption for colloid stabilization.

  3. Variability of assay methods for total and free PSA after WHO standardization.

    PubMed

    Foj, L; Filella, X; Alcover, J; Augé, J M; Escudero, J M; Molina, R

    2014-03-01

    The variability of total PSA (tPSA) and free PSA (fPSA) results among commercial assays has been suggested to be decreased by calibration to World Health Organization (WHO) reference materials. To characterize the current situation, it is necessary to know its impact in the critical cutoffs used in clinical practice. In the present study, we tested 167 samples with tPSA concentrations of 0 to 20 μg/L using seven PSA and six fPSA commercial assays, including Access, ARCHITECT i2000, ADVIA Centaur XP, IMMULITE 2000, Elecsys, and Lumipulse G1200, in which we only measured tPSA. tPSA and fPSA were measured in Access using the Hybritech and WHO calibrators. Passing-Bablok analysis was performed for PSA, and percentage of fPSA with the Hybritech-calibrated access comparison assay. For tPSA, relative differences were more than 10 % at 0.2 μg/L for ARCHITECT i2000, and at a critical concentration of 3, 4, and 10 μg/L, the relative difference was exceeded by ADVIA Centaur XP and WHO-calibrated Access. For percent fPSA, at a critical concentration of 10 %, the 10 % relative difference limit was exceeded by IMMULITE 2000 assay. At a critical concentration of 20 and 25 %, ADVIA Centaur XP, ARCHITECT i2000, and IMMULITE 2000 assays exceeded the 10 % relative difference limit. We have shown significant discordances between assays included in this study despite advances in standardization conducted in the last years. Further harmonization efforts are required in order to obtain a complete clinical concordance.

  4. 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.

  5. Application of PSA to storage of Pu at SRS

    SciTech Connect

    Lux, C.R.

    1995-12-01

    Pu is stored in a wide variety of physical forms and containers at the Savannah River Site (SRS). Probabilistic Safety Analysis (PSA) techniques are used to determine the risk associated with each of these storage modes and assist in identification of the controls necessary to minimize the risk. One storage method involves solids in exposed drum storage where the drums are vulnerable to external events, natural phenomena, and release of material due to weathering of the containers. Another storage method may involve liquids being processed inside the canyon facilities where the greatest risks are not from external events but from process upsets. PSA techniques have been particularly useful in the evaluation of criticality situations concerning Pu processing and storage. The applications include ``normal`` operating situations, problems following a seismic event, and the identification of potential problems during the decontamination and decommissioning of a facility. In this paper I would like to discuss two specific examples of the use of PSA techniques. The first involves the analysis of potential accidents in a Pu receipt and storage facility. The second example involves processing solutions that have the potential for experiencing an uncontrolled ``red oil`` reaction.

  6. 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)

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

    PubMed Central

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

    2003-01-01

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

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

    Cancer.gov

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

  9. 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.

  10. Theoretical study of the adsorption of aromatic units on carbon allotropes including explicit (empirical) DFT dispersion corrections and implicitly dispersion-corrected functionals: the pyridine case.

    PubMed

    Ramos-Berdullas, Nicolás; Pérez-Juste, Ignacio; Van Alsenoy, Christian; Mandado, Marcos

    2015-01-01

    The suitability of implicitly dispersion-corrected functionals, namely the M06-2X, for the determination of interaction energies and electron polarization densities in adsorption studies of aromatic molecules on carbon allotropes surfaces is analysed by comparing the results with those obtained using explicit dispersion through Grimme's empirical corrections. Several models of increasing size for the graphene sheet together with one-dimensional curved carbon structures, (5,5), (6,6) and (7,7) armchair single-walled nanotubes, and two-dimensional curved carbon structures, C60 fullerene, have been considered as substrates in this work, whereas pyridine has been chosen as an example for the adsorbed aromatic molecule. Comparison with recent experimental estimations of the adsorption energy and calculations using periodic boundary conditions on a supercell of 72 carbon atoms indicates that a finite model containing ninety six carbon atoms (C96) approaches quite well the adsorption on a graphene sheet. Analysis of the interaction energy components reveals that the M06-2X functional accounts for most of the dispersion energy implicitly, followed far by wB97X and B3LYP, whereas B97 and BLYP do not differ too much from HF. It has been found that M06-2X corrects only the energy component associated to dispersion and leaves the rest, electrostatic, Pauli and induction "unaltered" with respect to the other DFT functionals investigated. Moreover, only the M06-2X functional reflects the effect of dispersion on the electron polarization density, whereas for the remaining functionals the polarization density does not differ too much from the HF density. This makes the former functional more suitable a priori for the calculation of electron density related properties in these adsorption complexes.

  11. 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.

  12. 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

  13. Circulating insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) in PSA-detected prostate cancer: the large case control study ProtecT

    PubMed Central

    Rowlands, Mari-Anne; Holly, Jeff MP; Gunnell, David; Donovan, Jenny; Lane, J Athene; Hamdy, Freddie; Neal, David E; Oliver, Steven; Smith, George Davey; Martin, Richard M

    2011-01-01

    Circulating insulin-like growth factor-I (IGF-I) has been studied extensively in prostate cancer, but there is still little information about IGFs and IGF binding proteins (IGFBPs) in cancers detected by the prostate-specific antigen (PSA) test. Here we report the findings of a United Kingdom-based case-control study to investigate circulating IGFs and IGFBPs in PSA-detected prostate cancer with regard to their potential associations with different cancer stages or grades. PSA testing was offered to 110,000 men aged 50-69 years from 2002-2009. Participants with an elevated level of PSA (≥ 3.0 ng/ml) underwent prostate biopsy and measurements of blood serum IGF-I, IGF-II, IGFBP-2 and IGFBP-3 obtained at recruitment. We found that serum levels of IGF-II (OR per standard deviation increase: 1.16; 95%CI 1.08,1.24;ptrend<0.001), IGFBP-2 (1.18;1.06,1.31;ptrend<0.01) and IGFBP-3 (1.27;1.19,1.36;ptrend<0.001), but not IGF-I (0.99;0.93,1.04;ptrend=0.62), were associated with PSA-detected prostate cancer. After controlling for IGFBP-3, IGF-II was no longer associated (0.99;0.91,1.08;ptrend=0.62) and IGF-I was inversely associated (0.85;0.79,0.91;ptrend<0.001) with prostate cancer. In addition, no strong associations existed with cancer stage or grade. Overall, these findings suggest potentially important roles for circulating IGF-II, IGFBP-2 and IGFBP-3 in PSA-detected prostate cancer, in support of recent in vitro evidence. While our findings for IGF-I agree with previous results from PSA-screening trials, they contrast with positive associations in routinely-detected disease, suggesting that reducing levels of circulating IGF-I might not prevent the initiation of prostate cancer but might nonetheless prevent its progression. PMID:22106399

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

    PubMed

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

    1994-01-01

    During the week of September 16 to 22, 1990, commercials promoting drugs and alcohol outnumbered the networks' news stories, documentaries, and PSA's about illegal drugs by a ratio of almost 39-to-1. If you consider the PSA's alone, the commercials promoting drugs and alcohol outnumbered them by a ratio of almost 45-to-1. PMID:7869221

  15. Closing the gaps on the viral photosystem‐I  psaDCAB gene organization

    PubMed Central

    Roitman, Sheila; Flores‐Uribe, José; Philosof, Alon; Knowles, Ben; Rohwer, Forest; Ignacio‐Espinoza, J. Cesar; Sullivan, Matthew B.; Cornejo‐Castillo, Francisco M.; Sánchez, Pablo; Acinas, Silvia G.; Dupont, Chris L.

    2015-01-01

    Summary Marine photosynthesis is largely driven by cyanobacteria, namely Synechococcus and Prochlorococcus. Genes encoding for photosystem (PS) I and II reaction centre proteins are found in cyanophages and are believed to increase their fitness. Two viral PSI gene arrangements are known, psaJF→C→A→B→K→E→D and psaD→C→A→B. The shared genes between these gene cassettes and their encoded proteins are distinguished by %G + C and protein sequence respectively. The data on the psaD→C→A→B gene organization were reported from only two partial gene cassettes coming from Global Ocean Sampling stations in the Pacific and Indian oceans. Now we have extended our search to 370 marine stations from six metagenomic projects. Genes corresponding to both PSI gene arrangements were detected in the Pacific, Indian and Atlantic oceans, confined to a strip along the equator (30°N and 30°S). In addition, we found that the predicted structure of the viral PsaA protein from the psaD→C→A→B organization contains a lumenal loop conserved in PsaA proteins from Synechococcus, but is completely absent in viral PsaA proteins from the psaJF→C→A→B→K→E→D gene organization and most Prochlorococcus strains. This may indicate a co‐evolutionary scenario where cyanophages containing either of these gene organizations infect cyanobacterial ecotypes biogeographically restricted to the 30°N and 30°S equatorial strip. PMID:26310718

  16. Closing the gaps on the viral photosystem-I psaDCAB gene organization.

    PubMed

    Roitman, Sheila; Flores-Uribe, José; Philosof, Alon; Knowles, Ben; Rohwer, Forest; Ignacio-Espinoza, J Cesar; Sullivan, Matthew B; Cornejo-Castillo, Francisco M; Sánchez, Pablo; Acinas, Silvia G; Dupont, Chris L; Béjà, Oded

    2015-12-01

    Marine photosynthesis is largely driven by cyanobacteria, namely Synechococcus and Prochlorococcus. Genes encoding for photosystem (PS) I and II reaction centre proteins are found in cyanophages and are believed to increase their fitness. Two viral PSI gene arrangements are known, psaJF→C→A→B→K→E→D and psaD→C→A→B. The shared genes between these gene cassettes and their encoded proteins are distinguished by %G + C and protein sequence respectively. The data on the psaD→C→A→B gene organization were reported from only two partial gene cassettes coming from Global Ocean Sampling stations in the Pacific and Indian oceans. Now we have extended our search to 370 marine stations from six metagenomic projects. Genes corresponding to both PSI gene arrangements were detected in the Pacific, Indian and Atlantic oceans, confined to a strip along the equator (30°N and 30°S). In addition, we found that the predicted structure of the viral PsaA protein from the psaD→C→A→B organization contains a lumenal loop conserved in PsaA proteins from Synechococcus, but is completely absent in viral PsaA proteins from the psaJF→C→A→B→K→E→D gene organization and most Prochlorococcus strains. This may indicate a co-evolutionary scenario where cyanophages containing either of these gene organizations infect cyanobacterial ecotypes biogeographically restricted to the 30°N and 30°S equatorial strip. PMID:26310718

  17. 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.

  18. Does the size matter?: Prostate weight does not predict PSA recurrence after radical prostatectomy.

    PubMed

    Davidson, Darrell D; Koch, Michael O; Lin, Haiqun; Jones, Timothy D; Biermann, Katharina; Cheng, Liang

    2010-04-01

    Previous studies suggest that low prostate weight is a significant negative prognostic factor for prostate cancer. In the current study, the data for 431 men who underwent radical retropubic prostatectomy between 1990 and 1998 were analyzed for association between prostate weight and various clinical and pathologic parameters. These included age, preoperative prostate-specific antigen (PSA) level, PSA recurrence, pathologic stage, Gleason grade, extraprostatic extension, positive surgical margins, tumor volume, associated high-grade prostatic intraepithelial neoplasia, perineural invasion, and lymph node metastasis. Potential associations were probed by using Cox regression model analysis. A significant positive correlation was found between prostate weight and increasing patient age or increasing preoperative PSA level. There was no significant independent association between prostate weight and any of the other variables examined. No association was found between prostate weight and PSA recurrence. Although increasing prostate weight correlates with increased patient age and higher preoperative PSA level, it does not independently predict postoperative cancer recurrence.

  19. Multi-span transmission using phase and amplitude regeneration in PPLN-based PSA.

    PubMed

    Umeki, T; Asobe, M; Takara, H; Miyamoto, Y; Takenouchi, H

    2013-07-29

    We demonstrated multi-span transmission using a periodically poled LiNbO(3) (PPLN) based phase sensitive amplifier (PSA). An in-line PSA with a carrier recovery and phase locking system is implemented as a repeater amplifier in a recirculating loop. We achieved a PSA gain as high as + 18 dB and a high external gain of + 12 dB for the in-line PSA as a black box. The impairments caused by phase noise resulting from fiber nonlinearity and intensity noise caused by the amplified spontaneous emission (ASE) of an optical amplifier are largely suppressed using the phase and amplitude regeneration capabilities of the PSA. The ultra long-haul transmission of a 28-Gb/s binary phase shift keying (BPSK) signal over 5400 km was achieved with phase and amplitude regeneration.

  20. Protein Adsorption in Three Dimensions

    PubMed Central

    Vogler, Erwin A.

    2011-01-01

    initially-adsorbed protein. Interphase protein concentration CI increases as VI decreases, resulting in slow reduction in interfacial energetics. Steady-state is governed by a net partition coefficient P=(/CBCI). In the process of occupying space within the interphase, adsorbing protein molecules must displace an equivalent volume of interphase water. Interphase water is itself associated with surface-bound water through a network of transient hydrogen bonds. Displacement of interphase water thus requires an amount of energy that depends on the adsorbent surface chemistry/energy. This “adsorption-dehydration” step is the significant free-energy cost of adsorption that controls the maximum amount of protein that can be adsorbed at steady state to a unit adsorbent-surface area (the adsorbent capacity). As adsorbent hydrophilicity increases, protein adsorption monotonically decreases because the energetic cost of surface dehydration increases, ultimately leading to no protein adsorption near an adsorbent water wettability (surface energy) characterized by a water contact angle θ → 65°. Consequently, protein does not adsorb (accumulate at interphase concentrations greater than bulk solution) to more hydrophilic adsorbents exhibiting θ < 65° . For adsorbents bearing strong Lewis acid/base chemistry such as ion-exchange resins, protein/surface interactions can be highly favorable, causing protein to adsorb in multilayers in a relatively thick interphase. A straightforward, three-component free energy relationship captures salient features of protein adsorption to all surfaces predicting that the overall free energy of protein adsorption ΔGadso is a relatively small multiple of thermal energy for any surface chemistry (except perhaps for bioengineered surfaces bearing specific ligands for adsorbing protein) because a surface chemistry that interacts chemically with proteins must also interact with water through hydrogen bonding. In this way, water moderates protein

  1. Actual Contribution of Free to Total PSA Ratio in Prostate Diseases Differentiation

    PubMed Central

    Prcic, Alden; Begic, Edin; Hiros, Mustafa

    2016-01-01

    Objectives: To determine significance and sensitivity of the Free to Total prostate specific antigen (PSA) ratio (%fPSA) in diagnosis of prostate cancer and to correlate its sensitivity and specificity with diagnosis. Methods: Research included 220 patients, who had indication for biopsy (Clinic for Urology, University Clinical Center Sarajevo). Results: Average age of patients was 64.6 ± 8.1 years. Kruskal Wallis test indicates that there is a significant difference in age in relation to the diagnosis (KW χ2=12.508; p=0.006). The correlation between the %fPSA level and diagnosis is positive and statistically significant (r=0.211; p=0.002) in the sense that cancer patients have the lowest %fPSA. Analysis of the sensitivity at 95% specificity of %fPSA compared to particular diagnosis shows the highest sensitivity for prostate cancer - 20.61% (8.35-31.02) with statistically significant AUC p<0.05. Analysis of %fPSA test in detecting prostate cancer, at cut-off values ≤ 0.16, shows a sensitivity of 72.3% and specificity of 50.4 (at cut-off values <0.07, sensitivity is 8.4%, and specificity is 97.8%). Conclusion: PSA is organ specific but not cancer specific marker, whose total value, as well as the %fPSA serve as a basis, with a digitorectal exam, in the detection of prostate cancer. By increasing the cut-off values sensitivity of %fPSA increases and specificity decreases. %fPSA has a relative importance in the detection of prostate cancer, and should not be used as a guideline, without prior clinical examination. PMID:27703291

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

    PubMed Central

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

    2016-01-01

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

  3. 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

  4. 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

  5. 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.

  6. 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.

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2014-01-01

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

  9. The PSA tracker: A computerised health care system initiative in Northern Ireland

    PubMed Central

    Hennessey, Derek B; Lynn, Caoibhe; Templeton, Hazel; Chambers, Kerry; Mulholland, Colin

    2013-01-01

    Intoduction The follow-up of men with prostate cancer forms a large part of many urologists workload. However, a rising PSA usually announces disease progression long before any clinically apparent symptom. Thus, many men can be safely monitored with PSA measurement alone. To facilitate this process, PSA tracking software was introduced to remotely monitor PSA results, minimising the work required for follow-up. Methods Stable prostate cancer patients were into the PSA tracker. When each PSA test was performed, the result was reviewed. The program automatically generated patient reminder letters, summary reports for clinic use and all correspondence to patients and primary care physicians. Results Since 2006, 65 patients have been entered into the PSA tracker. Median age was 81 (57–94) years. 274 outpatient appointments have been saved, indicating a potential saving of £32,000. More importantly it increased the capacity of the department to assess new patients. For the individual patient, the system has saved them, a median of 3 appointments each. Conclusion Remote follow-up of prostate cancer is associated with significant savings for both healthcare organisations and individual patients. This example, further demonstrates the benefits of implanting healthcare software for patients and hospitals. PMID:24505148

  10. 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.

  11. 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.

  12. PSA modification of NCAM supports the survival of injured retinal ganglion cells in adulthood.

    PubMed

    Lobanovskaya, Natalia; Zharkovsky, Tamara; Jaako, Külli; Jürgenson, Monika; Aonurm-Helm, Anu; Zharkovsky, Alexander

    2015-11-01

    Neural cell adhesion molecule (NCAM) is known as the cell surface glycoprotein, and it belongs to the immunoglobulin superfamily of adhesion molecules. Polysialic acid (PSA) is a carbohydrate attached to NCAM via either of two specific sialyltransferases: ST8SiaII and ST8SiaIV. Polysialylated neural cell adhesion molecule (PSA-NCAM) mediates cell interactions, plays a role in axon growth, migration, synaptic plasticity during development and cell regeneration. Some evidence has shown that PSA-NCAM supports the survival of neurons. It was demonstrated that PSA-NCAM is present in abundance in the retina during development and in adulthood. The aim of this study was to investigate whether PSA-NCAM promotes retinal ganglion cell (RGC) survival in transgenic mice with deficiencies in sialyltransferases or NCAM or after the administration of endoneuraminidase (Endo-N). RGC injury was induced by intravitreal administration of kainic acid (KA). These studies showed that injection of Endo-N after 14 days enhances the toxicity of KA to RGCs in wild-type (WT) mice by 18%. In contrast, in knockout mice (ST8SiaII-/-, ST8SiaIV-/-, NCAM-/-), survival of RGCs after KA injury did not change. Deficiencies of either ST8SiaII or ST8SiaIV did not influence the level of PSA-NCAM in the adult retina, however, in neonatal animals, decreased levels of PSA-NCAM were observed. In knockout ST8SiaII-/- adults, a reduced number of RGCs was detected, whereas in contrast, increased numbers of RGCs were noted in NCAM-/- mice. In conclusion, these data demonstrate that PSA-NCAM supports the survival of injured RGCs in adulthood. However, the role of PSA-NCAM in the adult retina requires further clarification. PMID:26319680

  13. Protein Adsorption in Three Dimensions

    PubMed Central

    Vogler, Erwin A.

    2011-01-01

    initially-adsorbed protein. Interphase protein concentration CI increases as VI decreases, resulting in slow reduction in interfacial energetics. Steady-state is governed by a net partition coefficient P=(/CBCI). In the process of occupying space within the interphase, adsorbing protein molecules must displace an equivalent volume of interphase water. Interphase water is itself associated with surface-bound water through a network of transient hydrogen bonds. Displacement of interphase water thus requires an amount of energy that depends on the adsorbent surface chemistry/energy. This “adsorption-dehydration” step is the significant free-energy cost of adsorption that controls the maximum amount of protein that can be adsorbed at steady state to a unit adsorbent-surface area (the adsorbent capacity). As adsorbent hydrophilicity increases, protein adsorption monotonically decreases because the energetic cost of surface dehydration increases, ultimately leading to no protein adsorption near an adsorbent water wettability (surface energy) characterized by a water contact angle θ → 65°. Consequently, protein does not adsorb (accumulate at interphase concentrations greater than bulk solution) to more hydrophilic adsorbents exhibiting θ < 65° . For adsorbents bearing strong Lewis acid/base chemistry such as ion-exchange resins, protein/surface interactions can be highly favorable, causing protein to adsorb in multilayers in a relatively thick interphase. A straightforward, three-component free energy relationship captures salient features of protein adsorption to all surfaces predicting that the overall free energy of protein adsorption ΔGadso is a relatively small multiple of thermal energy for any surface chemistry (except perhaps for bioengineered surfaces bearing specific ligands for adsorbing protein) because a surface chemistry that interacts chemically with proteins must also interact with water through hydrogen bonding. In this way, water moderates protein

  14. 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

  15. 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

  16. 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.

  17. 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

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

    PubMed

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

    2001-06-01

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

  19. Predicting Biochemical Failure and Overall Survival Through Intratherapy PSA Changes During Definitive External Beam Radiotherapy

    SciTech Connect

    Soto, Daniel E.; Andridge, Rebecca R.; Taylor, Jeremy M.G.; McLaughlin, Patrick W.; Sandler, Howard M.; Pan, Charlie C.

    2008-12-01

    Purpose: To determine whether intratherapy prostate-specific antigen (itPSA) changes during radiotherapy (RT) predict prostate cancer outcomes. Methods and Materials: We retrospectively identified patients treated with definitive external beam RT without hormonal therapy who had at least two itPSA measurements. We calculated the adjusted ratio of rise (ARR) in itPSA relative to the pretreatment baseline PSA for each patient. This was defined as ln(maximal itPSA + 1)/ln(baseline PSA + 1). We stratified patients according to an ARR of <1 vs. >1.1. This corresponded to an approximately <30% vs. >30% increase in PSA during RT. Univariate and multivariate analyses were performed examining for biochemical failure-free survival (BFFS) and overall survival (OS). Results: At a median follow-up of 74 months, we identified 307 patients who met our criteria. Univariate analysis revealed that patients with an ARR of <1.1 (n = 182) had statistically significant inferior BFFS and OS compared with those with an ARR of >1.1 (n = 125). The median BFFS and OS for these two groups was 51 vs. 101 months (p = 0.001) and 96 vs. 128 months (p = 0.01), respectively. On multivariate analysis, the effect of ARR on the risk of biochemical failure for patients with an ARR of <1.1 was significant (p = 0.03) only during the first year after RT. In contrast, the effect of the ARR on OS remained significant for a full 5 years (p = 0.05). Conclusion: The results of our study have shown that an ARR of <1.1 predicts for inferior BFFS and OS in patients treated with RT alone. PSA measurement during RT is a novel clinical tool that could be used to identify patients who might warrant more aggressive therapeutic intervention.

  20. 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

  1. 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

  2. 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

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

    PubMed Central

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

    2016-01-01

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

  4. 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.

  5. 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

  6. High Adsorption of Sulfamethoxazole by an Amine-Modified Polystyrene-Divinylbenzene Resin and Its Mechanistic Insight.

    PubMed

    Ling, Chen; Li, Xiaoyun; Zhang, Zhiyun; Liu, Fuqiang; Deng, Yingqing; Zhang, Xiaopeng; Li, Aimin; He, Lili; Xing, Baoshan

    2016-09-20

    Sulfamethoxazole (SMZ) adsorption by a series of amine-modified polystyrene-divinylbenzene resins (PSA/B/C/D) was investigated. All resins showed a similar pH dependent adsorption of SMZ but their capacities were linearly related with the contents of primary amines (-NH2) rather than secondary amines (-NH-). Mechanisms of SMZ adsorption by PSA (highest -NH2 content) were discussed as an example. Due to comparable pKa, H-bonding interactions of -NH2(0) with SMZ(0) (regular H-bond) and SMZ(-) (negative charge-assisted H-bond, (-)CAHB) successively contributed most adsorption (pH 4-9). At weakly acidic pH, -NH2(0) was partially protonated and electrostatic attraction between -NH3(+) and SMZ(-) occurred concurrently, but could be hindered by increased loading of SMZ(0). Hydrophobic/ π-π interactions were not major mechanisms as phenanthrene and nitrobenzenes had little effect on SMZ adsorption. At alkaline pH, where SMZ(-) and -NH2(0) prevailed, adsorption was accompanied by the stoichiometric (∼1.0) proton exchange with water, leading to OH(-) release and the formation of (-)CAHB [SO2N(-)···H···NH2]. The interaction and SMZ spatial distribution in the resin-phase were further confirmed by FTIR and Raman spectra. SMZ was uniformly adsorbed on external and interior surfaces. SMZ adsorption by PSA had low-interference from other coexistent matter, but high stability after multiple regenerations. The findings will guide new adsorbent designs for selectively removing target organics.

  7. 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

  8. 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

    Scientific and engineering data from the European Space Agency'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. All data in the PSA are compatible with the Planetary Data System (PDS) Standard of NASA, and the PSA staff work in close collaboration with the PDS staff. One major part of the ongoing development of the IPDA (International Planetary Data Alliance) has been to draw upon the lessons learned on both sides of this working relationship in order to refine and streamline the Standards. This is driving towards ‘interoperability' of the data systems maintained at all Agencies archiving planetary data, and it is hoped that in the long-run any data can be obtained from any of the co-operating archives using the same protocol. Currently, the PSA contains data from the GIOTTO spacecraft, several ground-based cometary observations, and the Mars Express, Smart-1, and Huygens missions. Independent reviews for the first Venus Express data are schedule for Spring 2008 and the first Venus Express data should be released on the PSA in late spring 2008. The first data release from the ROSETTA mission is also expected to be released on the PSA by spring 2008. Preparation for the release of data from the SMART-1 spacecraft is ongoing. Future missions such as ExoMars and Bepi- Colombo will also aim to work with the PSA to distribute their data to the community. 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

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    The Planetary Science Archive (PSA) is the European Space Agency's (ESA) repository of science data from all planetary science and exploration missions. The PSA provides access to scientific datasets through various interfaces at http://archives.esac.esa.int/psa. All datasets are scientifically peer-reviewed by independent scientists, and are compliant with the Planetary Data System (PDS) standards. The PSA is currently implementing a number of significant improvements, mostly driven by the evolution of the PDS standard, and the growing need for better interfaces and advanced applications to support science exploitation. The newly designed PSA will enhance the user experience and will significantly reduce the complexity for users to find their data promoting one-click access to the scientific datasets with more specialised views when needed. This includes a better integration with Planetary GIS analysis tools and Planetary interoperability services (search and retrieve data, supporting e.g. PDAP, EPN-TAP). It will be also up-to-date with versions 3 and 4 of the PDS standards, as PDS4 will be used for ESA's ExoMars and upcoming BepiColombo missions. Users will have direct access to documentation, information and tools that are relevant to the scientific use of the dataset, including ancillary datasets, Software Interface Specification (SIS) documents, and any tools/help that the PSA team can provide. A login mechanism will provide additional functionalities to the users to aid / ease their searches (e.g. saving queries, managing default views). This contribution will introduce the new PSA, its key features and access interfaces.

  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. 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

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

    PubMed

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

    2014-01-01

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

  13. Correlation Between Testosterone and PSA Kinetics in Metastatic Prostate Cancer Patients Treated With Diverse Chemical Castrations.

    PubMed

    Reis, Leonardo O; Denardi, Fernandes; Faria, Eliney F; Silva, Elcio Dias

    2015-09-01

    To assess total testosterone and prostatic-specific antigen (PSA) kinetics among diverse chemical castrations, advanced-stage prostate cancer patients were randomized into three groups of 20: Group 1, Leuprolide 3.75 mg; Group 2, Leuprolide 7.5 mg; and Group 3, Goserelin 3.6 mg. All groups were treated with monthly application of the respective drugs. The patients' levels of serum total testosterone and PSA were evaluated at two time periods: before the treatment and 3 months after the treatment. Spearman's rank correlation coefficient was utilized to verify the hypothesis of linear correlation between total testosterone and PSA levels. At the beginning the patients' age, stage, grade, PSA, and total testosterone were similar within the three groups, with median age 72, 70, and 70 years in Groups 1, 2, and 3, respectively. Three months after the treatment, patients who received Leuprolide 7.5 mg presented significantly lower median total testosterone levels compared with Goserelin 3.6 mg and Leuprolide 3.75 mg (9.5 ng/dL vs. 20.0 ng/dL vs. 30.0 ng/dL, respectively; p = .0072), while those who received Goserelin 3.6 mg presented significantly lower PSA levels compared with Leuprolide 7.5 mg and Leuprolide 3.75 mg (0.67 vs. 1.86 vs. 2.57, respectively; p = .0067). There was no linear correlation between total testosterone and PSA levels. Overall, regarding castration levels of total testosterone, 28.77% of patients did not obtain levels ≤50 ng/dL and 47.80% did not obtain levels ≤20 ng/dL. There was no correlation between total testosterone and PSA kinetics and no equivalence among different pharmacological castrations.

  14. Clinically insignificant improvement of prostate cancer prediction by addition of sex steroid hormones and SHBG serum levels to serum PSA, fPSA%, and age in a screening setting.

    PubMed

    Heidegger, Isabel; Popovscaia, Marina; Ramoner, Reinhold; Schäfer, Georg; Stenzel, Birgit; Bektic, Jasmin; Horninger, Wolfgang; Klocker, Helmut

    2012-10-01

    Abstract Various findings implicate sex hormones in prostate growth and development and also in prostate carcinogenesis. We investigated if addition of sex steroid hormone and sex hormone binding globulin (SHBG) serum levels to standard risk assessment parameters [prostate-specific antigen (PSA), free PSA percentage (fPSA%), and age] improves prostate cancer prediction in a PSA screening setting. Steroid hormones testosterone (T), free testosterone (fT), and estradiol (E2), and binding protein SHBG levels were measured in 762 men undergoing prostate biopsy due to suspect PSA serum levels. Prostate cancer was diagnosed in 286 (37.5%) of these men. Our data confirmed that PSA (mean BE=5.09; mean CA=6.05; p=1.24×10-5), fPSA% (mean BE=22.08; mean CA=18.67; p=1.97×10-7), and age (mean BE=60.64; mean CA=64.5; p=7.05×10-10) differentiate men with cancer (CA) and men with benign disease (BE), such as benign prostate hyperplasia. In addition, SHBG (mean BE=50.3; mean CA=54.9; p=0.008) also differed statistically significantly between these two groups. All hormones except E2 and tumor markers correlated significantly with age (T: ρ=-0.09; fT: ρ=-0.27; SHBG: ρ=0.21; PSA: ρ=0.32; and fPSA%: ρ=0.22). Furthermore, we found that PSA correlates with E2 (ρ=0.08), and fPSA% with SHBG (ρ=0.1) and fT (ρ=-0.09). Addition of hormones and SHBG to a baseline marker model including PSA, fPSA%, and age improved cancer prediction in three multivariate classification methods; however, the improvement was minimal. The best improvement by 0.8% was obtained in the logistic regression model with the addition of T and SHBG or of E2 and SHBG, or in the support vector machine model with the addition of SHBG and all steroid hormones to the combination of standard markers PSA, fPSA%, and age; however, this additional gain of accuracy is too small to justify the additional efforts and costs.

  15. Peer review of the Barselina Level 1 probabilistic safety assessment of the Ignalina Nuclear Power Plant, Unit 2

    SciTech Connect

    McKay, S.L.; Coles, G.A.

    1995-01-01

    The Barselina Project is a Swedish-funded, cooperative effort among Lithuania, Russia and Sweden to transfer Western probabilistic safety assessment (PSA) methodology to the designers/operators of Ignalina Nuclear Power Plant (INPP). The overall goal is to use the PSA as a tool for assessing plant operational safety. The INPP is a two-unit, Former Soviet Union-designed nuclear facility located in Lithuania. The results of this PSA will ultimately be used to identify plant-specific improvements in system design and the conduct of facility operations, allowing improved operational safety. Pacific Northwest Laboratory (PNL) was asked to perform an independent expert peer review of the Barselina PSA. This report documents the findings of this review. This review, financed with nuclear safety assistance funds through the US Agency for International Development (USAID) and the US Department of Energy (DOE), satisfies Task II of the PNL peer review of the Barselina project. The objective is to provide an independent, in-proce ss examination of the Barselina Level 1 PSA of Ignalina Nuclear Power Plant, Unit 2. The review consisted of an investigation of the project documentation, interviews, and extensive discussions with the PSA staff during critical stages of the project. PNL assessed the readability, completeness, consistency, validity, and applicability of the PSA. The major aspects explored were its purpose, major assumptions, analysis/modeling, results, and interpretation. It was not within the scope of this review to perform plant walkdowns or to review material other than the PSA documentation.

  16. [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

  17. Study of possibility using LANL PSA-methodology for accident probability RBMK researches

    SciTech Connect

    Petrin, S.V.; Yuferev, V.Y.; Zlobin, A.M.

    1995-12-31

    The reactor facility probabilistic safety analysis methodologies are considered which are used at U.S. LANL and RF NIKIET. The methodologies are compared in order to reveal their similarity and differences, determine possibilities of using the LANL technique for RBMK type reactor safety analysis. It is found that at the PSA-1 level the methodologies practically do not differ. At LANL the PHA, HAZOP hazards analysis methods are used for more complete specification of the accounted initial event list which can be also useful at performance of PSA for RBMK. Exchange of information regarding the methodology of detection of dependent faults and consideration of human factor impact on reactor safety is reasonable. It is accepted as useful to make a comparative study result analysis for test problems or PSA fragments using various computer programs employed at NIKIET and LANL.

  18. 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

  19. Heavy metal adsorption changes of EAF steel slag after phosphorus adsorption.

    PubMed

    Song, Guanling; Cao, Lijing; Chen, Xiao; Hou, Wenhua; Wang, Qunhui

    2012-01-01

    A kind of electric arc furnace (EAF) steel slag was phosphated, and its isothermal and dynamic adsorptions of copper, cadmium, and lead ions were measured to determine if heavy metal adsorption changes after phosphorus adsorption. The surface area increased greatly after the slag was phosphated. Isothermal adsorption experiments showed that the theoretical Q(max) of the EAF steel slag on Cu(2+), Cd(2+), and Pb(2+) improved 59, 50, and 89% respectively after it was phosphated. Dynamic adsorption results showed that the greatest adsorption capacities of unit volume of Cu(2+), Cd(2+), and Pb(2+) were 2.2, 1.8, and 1.8 times that of the column packed with original EAF steel slag when the column was packed with phosphate EAF steel slag at the same heavy metal ion concentration. The breakthrough time, the exhaustion time and elution efficiency of the column also increased when the column was packed with phosphated EAF steel slag compared with that packed with original EAF steel slag. Phosphorus adsorption could further improve the heavy metal ion adsorption of the EAF steel slag.

  20. Doctors’ approaches to PSA testing and overdiagnosis in primary healthcare: a qualitative study

    PubMed Central

    Pickles, Kristen; Carter, Stacy M; Rychetnik, Lucie

    2015-01-01

    Objectives (1) To explain general practitioners’ (GPs’) approaches to prostate-specific antigen (PSA) testing and overdiagnosis; (2) to explain how GPs reason about their PSA testing routines and (3) to explain how these routines influence GPs’ personal experience as clinicians. Setting Primary care practices in Australia including men's health clinics and rural practices with variable access to urology services. Participants 32 urban and rural GPs within Australia. We included GPs of varying ages, gender (11 female), clinical experience and patient populations. All GPs interested in participating in the study were included. Primary and secondary outcome measure(s) Data were analysed using grounded theory methods to determine how and why GPs provide (or do not provide) PSA testing to their asymptomatic male patients. Results We observed patterned variation in GP practice, and identified four heuristics to describe GP preference for, and approaches to, PSA testing and overdiagnosis: (1) GPs who prioritised avoiding underdiagnosis, (2) GPs who weighed underdiagnosis and overdiagnosis case by case, (3) GPs who prioritised avoiding overdiagnosis and (4) GPs who did not engage with overdiagnosis at all. The heuristics guided GPs’ Routine Practice (usual testing, communication and responses to patient request). The heuristics also reflected GPs’ different Practice Rationales (drawing on experience, medicolegal obligations, guidelines and evidence) and produced different Practice Outcomes (GPs’ experiences of the consequences of their PSA testing decisions). Some of these heuristics were more responsive to patient preferences than others. Conclusions Variation in GPs’ PSA testing practices is strongly related to their approach to overdiagnosis and underdiagnosis of prostate cancer. Men receive very different care depending on their GP's reasoning and practice preferences. Future policy to address overdiagnosis will be more likely to succeed if it responds to

  1. 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.

  2. 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.

  3. [Contribution of PSA and its density in the diagnosis and tracking of the prostate cancer].

    PubMed

    Yousra, Souiden; Rafik, Elkamel; Manel, Mahdouani; Kacem, Mahdouani

    2010-01-01

    Owing to the fact that prostate cancer is the second cause of death behind lung cancer, several diagnostic strategies have been introduced in the past years. Among these prostate specific antigen is widely acknowledged to be the simplest and routine clinical parameter the purpose of this study is to reveal the contribution of the prostate specific antigen (PSA) in the diagnosis and tracking of prostate cancer compared to the PSA density (PSAD). 182 unrelated Tunisian men divided in two groups were considered by this study. The first, formed of 116 patients, comprised 91 subjects with a prostate benign hyperplasia (HBP) and 25 patients developing a prostate cancer (CaP). The second included 66 men without symptomatology of prostate pathologies. The serum prostate specific antigen values are measured in all the cases by immunoenzymatic method. However, the clinical characteristics of all subjects of the first group were determined by recourse to Gleason score, digital rectal examination and prostate echography. Nevertheless, those of the second group were given just for 7 subjects with PSA>4 ng/mL by making a biopsy. The present study shows, on the one hand, a clear correlation between PSA level and prostate pathology frequencies in a Tunisian population, on the other, it demonstrates a considerable relationship between the pathologic PSA level and patient age especially in the 7th decade. Besides, it points out to the contribution of additional parameters essentially the PSAD. PSA measurement can be considered as a reliable tool for early detection, staging, and monitoring of prostate cancer in elderly men even in the absence of clinical signs only for remarkable high levels (>20 ng/mL). Conversely, it cannot be in case of moderate levels (4≤PSA≥20 ng/mL) from where, the need of its combination to other complementary parameters specifically the PSAD which is very beneficial for early diagnosis of the prostate cancer. In fact, when compared to the result of

  4. Potential selection bias in a community-based study of PSA levels in African-American men.

    PubMed

    Heeringa, S G; Alcser, K H; Doerr, K; Strawderman, M; Cooney, K; Medbery, B; Schottenfeld, D

    2001-02-01

    The first phase of the Flint Men's Health Study (FMHS) in Michigan was a community-based epidemiologic study of prostate cancer and benign prostatic hyperplasia (BPH) in African-Americans aged 40 to 79 years. An objective of the FMHS was to determine age-specified prostate specific antigen (PSA) reference ranges in a random population sample of African-American men without clinically evident prostate cancer. The FMHS study protocol included an initial in-home epidemiologic interview followed by PSA testing and a urologic examination of eligible subjects. Since the participation rate in the PSA phase of the study was under 60%, it was important to determine whether selectivity in participation biased the FMHS results for age-specific PSA distributions. Logistic regression analyses were used to investigate selectivity in the sample of subjects who participated in the PSA testing and urologic examination. Younger men, with current urologic symptoms, and with a family history of prostate cancer were more likely to participate in the PSA testing and urologic examination. Linear regression analysis indicated that greater participation by African-American men without clinically evident prostate cancer but with obstructive or irritative lower urinary tract symptoms or a family history of prostate cancer did not bias the estimated age-specific reference ranges for total PSA concentrations and free-to-total PSA ratios.

  5. Expression of prostate-specific antigen (PSA) correlates with poor response to tamoxifen therapy in recurrent breast cancer

    PubMed Central

    Foekens, J A; Diamandis, E P; Yu, H; Look, M P; Gelder, M E Meijer-van; Klijn, J G M

    1999-01-01

    Prostate-specific antigen (PSA) is a serine protease which may play a role in a variety of cancer types, including breast cancer. In the present study, we evaluated whether the level of PSA in breast tumour cytosol could be associated with prognosis in primary breast cancer, or with response to tamoxifen therapy in recurrent disease. PSA levels were determined by enzyme-linked immunosorbent assay (ELISA) in breast tumour cytosols, and were correlated with prognosis in 1516 patients with primary breast cancer and with response to first-line tamoxifen therapy in 434 patients with recurrent disease. Relating the levels of PSA with classical prognostic factors, low levels were more often found in larger tumours, tumours of older and post-menopausal patients, and in steroid hormone receptor-negative tumours. There was no significant association between the levels of PSA with grade of differentiation or the number of involved lymph nodes. In patients with primary breast cancer, PSA was not significantly related to the rate of relapse, and a positive association of PSA with an improved survival could be attributed to its relationship to age. In patients with recurrent breast cancer, a high level of PSA was significantly related to a poor response to tamoxifen therapy, and a short progression-free and overall survival after start of treatment for recurrent disease. In Cox multivariate analyses for response to therapy and for (progression-free) survival, corrected for age/menopausal status, disease-free interval, site of relapse and steroid hormone receptor status, PSA was an independent variable of poor prognosis. It is concluded that the level of PSA in cytosols of primary breast tumours might be a marker to select breast cancer patients who may benefit from systemic tamoxifen therapy. © 1999 Cancer Research Campaign PMID:10070886

  6. 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. |

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

    PubMed

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

    2015-06-11

    A label-free and selective aptamer beacon-based Love-wave biosensing device was developed for prostate specific antigen (PSA) detection. The device consists of the following parts: LiTaO3 substrate with SiO2 film as wave guide layer, two set of inter-digital transducers (IDT), gold film for immobilization of the biorecongniton layer and a polydimethylsiloxane (PDMS) microfluidic channels. DNA aptamer, or "artificial antibody", was used as the specific biorecognition probe for PSA capture. Some nucleotides were added to the 3'-end of the aptamer to form a duplex with the 3'-end, turning the aptamer into an aptamer-beacon. Taking advantage of the selective target-induced assembly changes arising from the "aptamer beacon", highly selective and specific detection of PSA was achieved. Furthermore, PDMS microfluidic channels were designed and fabricated to realize automated quantitative sample injection. After optimization of the experimental conditions, the established device showed good performance for PSA detection between 10 ng/mL to 1 μg/mL, with a detection limit of 10 ng/mL. The proposed sensor might be a promising alternative for point of care diagnostics.

  8. 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. |

  9. 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.

  10. 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…

  11. 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

  12. 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

  13. 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.

  14. A Simple Adsorption Experiment

    ERIC Educational Resources Information Center

    Guirado, Gonzalo; Ayllon, Jose A.

    2011-01-01

    The study of adsorption phenomenon is one of the most relevant and traditional physical chemistry experiments performed by chemistry undergraduate students in laboratory courses. In this article, we describe an easy, inexpensive, and straightforward way to experimentally determine adsorption isotherms using pieces of filter paper as the adsorbent…

  15. Extracts from Epilobium sp. herbs, their components and gut microbiota metabolites of Epilobium ellagitannins, urolithins, inhibit hormone-dependent prostate cancer cells-(LNCaP) proliferation and PSA secretion.

    PubMed

    Stolarczyk, Magdalena; Piwowarski, Jakub P; Granica, Sebastian; Stefańska, Joanna; Naruszewicz, Marek; Kiss, Anna K

    2013-12-01

    Extracts from Epilobium sp. herbs have been traditionally used in the treatment of prostate-associated ailments. Our studies demonstrated that the extracts from Epilobium angustifolium, Epilobium parviflorum and Epilobium hirsutum herbs are potent prostate cancer cells (LNCaP) proliferation inhibitors with IC50 values around 35 µg/ml. The tested extracts reduced prostate specific antigen (PSA) secretion (from 325.6 ± 25.3 ng/ml to ~90 ng/ml) and inhibited arginase activity (from 65.2 ± 1.1 mUnits of urea/mg of protein to ~40 mUnits of urea/mg protein). Selected constituents of extracts (oenothein B, quercetin-3-O-glucuronide, myricetin-3-O-rhamnoside) were proven to be active in relation to LNCaP cells. However, oenothein B was the strongest inhibitor of cells proliferation (IC50  = 7.8 ± 0.8 μM), PSA secretion (IC50  = 21.9 ± 3.2 μM) and arginase activity (IC50 = 19.2 ± 2.0 μM). Additionally, ellagitannins from E. hirustum extract were proven to be transformed by human gut microbiota into urolithins. Urolithin C showed the strongest activity in the inhibition of cell proliferation (IC50  = 35.2 ± 3.7 μM), PSA secretion (reduced PSA secretion to the level of 100.7 ± 31.0 ng/ml) and arginase activity (reduced to the level of 27.9 ± 3.3 mUnits of urea/mg of protein). Results of the work offer an explanation of the activity of Epilobium extracts and support the use of Epilobium preparations in the treatment of prostate diseases. PMID:23436427

  16. Extracts from Epilobium sp. herbs, their components and gut microbiota metabolites of Epilobium ellagitannins, urolithins, inhibit hormone-dependent prostate cancer cells-(LNCaP) proliferation and PSA secretion.

    PubMed

    Stolarczyk, Magdalena; Piwowarski, Jakub P; Granica, Sebastian; Stefańska, Joanna; Naruszewicz, Marek; Kiss, Anna K

    2013-12-01

    Extracts from Epilobium sp. herbs have been traditionally used in the treatment of prostate-associated ailments. Our studies demonstrated that the extracts from Epilobium angustifolium, Epilobium parviflorum and Epilobium hirsutum herbs are potent prostate cancer cells (LNCaP) proliferation inhibitors with IC50 values around 35 µg/ml. The tested extracts reduced prostate specific antigen (PSA) secretion (from 325.6 ± 25.3 ng/ml to ~90 ng/ml) and inhibited arginase activity (from 65.2 ± 1.1 mUnits of urea/mg of protein to ~40 mUnits of urea/mg protein). Selected constituents of extracts (oenothein B, quercetin-3-O-glucuronide, myricetin-3-O-rhamnoside) were proven to be active in relation to LNCaP cells. However, oenothein B was the strongest inhibitor of cells proliferation (IC50  = 7.8 ± 0.8 μM), PSA secretion (IC50  = 21.9 ± 3.2 μM) and arginase activity (IC50 = 19.2 ± 2.0 μM). Additionally, ellagitannins from E. hirustum extract were proven to be transformed by human gut microbiota into urolithins. Urolithin C showed the strongest activity in the inhibition of cell proliferation (IC50  = 35.2 ± 3.7 μM), PSA secretion (reduced PSA secretion to the level of 100.7 ± 31.0 ng/ml) and arginase activity (reduced to the level of 27.9 ± 3.3 mUnits of urea/mg of protein). Results of the work offer an explanation of the activity of Epilobium extracts and support the use of Epilobium preparations in the treatment of prostate diseases.

  17. Centrifugal Adsorption Cartridge System

    NASA Technical Reports Server (NTRS)

    Gonda, Steve R.; Tsao, Yow-Min D.; Lee, Wenshan

    2004-01-01

    The centrifugal adsorption cartridge system (CACS) is an apparatus that recovers one or more bioproduct(s) from a dilute aqueous solution or suspension flowing from a bioreactor. The CACS can be used both on Earth in unit gravity and in space in low gravity. The CACS can be connected downstream from the bioreactor; alternatively, it can be connected into a flow loop that includes the bioreactor so that the liquid can be recycled. A centrifugal adsorption cartridge in the CACS (see figure) includes two concentric cylinders with a spiral ramp between them. The volume between the inner and outer cylinders, and between the turns of the spiral ramp is packed with an adsorbent material. The inner cylinder is a sieve tube covered with a gas-permeable, hydrophobic membrane. During operation, the liquid effluent from the bioreactor is introduced at one end of the spiral ramp, which then constrains the liquid to flow along the spiral path through the adsorbent material. The spiral ramp also makes the flow more nearly uniform than it would otherwise be, and it minimizes any channeling other than that of the spiral flow itself. The adsorbent material is formulated to selectively capture the bioproduct(s) of interest. The bioproduct(s) can then be stored in bound form in the cartridge or else eluted from the cartridge. The centrifugal effect of the spiral flow is utilized to remove gas bubbles from the liquid. The centrifugal effect forces the bubbles radially inward, toward and through the membrane of the inner cylinder. The gas-permeable, hydrophobic membrane allows the bubbles to enter the inner cylinder while keeping the liquid out. The bubbles that thus enter the cylinder are vented to the atmosphere. The spacing between the ramps determines rate of flow along the spiral, and thereby affects the air-bubble-removal efficiency. The spacing between the ramps also determines the length of the fluid path through the cartridge adsorbent, and thus affects the bioproduct

  18. Protein Adsorption on Surfaces with Grafted Polymers

    PubMed Central

    Szleifer, I.

    1997-01-01

    A general theoretical framework for studying the adsorption of protein molecules on surfaces with grafted polymers is presented. The approach is a generalization of the single-chain mean-field theory, in which the grafted polymer-protein-solvent layer is assumed to be inhomogeneous in the direction perpendicular to the grafting surface. The theory enables the calculation of the adsorption isotherms of the protein as a function of the surface coverage of grafted polymers, concentration of protein in bulk, and type of solvent molecules. The potentials of mean force of the protein with the surface are calculated as a function of polymer surface coverage and amount of protein adsorbed. The theory is applied to model lysozyme on surfaces with grafted polyethylene oxide. The protein is modeled as spherical in solution, and it is assumed that the protein-polymer, protein-solvent, and polymer-solvent attractive interactions are all equal. Therefore, the interactions determining the structure of the layer (beyond the bare polymer-surface and protein-surface interactions) are purely repulsive. The bare surface-protein interaction is taken from atomistic calculations by Lee and Park. For surfaces that do not have preferential attractions with the grafted polymer segments, the adsorption isotherms of lysozyme are independent of the polymer length for chains with more than 50 ethylene oxide units. However, the potentials of mean force show strong variations with grafted polymer molecular weight. The competition between different conformations of the adsorbed protein is studied in detail. The adsorption isotherms change qualitatively for surfaces with attractive interactions with ethylene oxide monomers. The protein adsorption is a function of chain length—the longer the polymer the more effective it is in preventing protein adsorption. The structure of the layer and its deformation upon protein adsorption are very important in determining the adsorption isotherms and the

  19. 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

  20. 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

  1. Prostate-Specific Antigen (PSA) Screening and New Biomarkers for Prostate Cancer (PCa)

    PubMed Central

    Rittenhouse, Harry; Hu, Xinhai; Cammann, Henning; Jung, Klaus

    2014-01-01

    Abstract PSA screening reduces PCa-mortality but the disadvantages overdiagnosis and overtreatment require multivariable risk-prediction tools to select appropriate treatment or active surveillance. This review explains the differences between the two largest screening trials and discusses the drawbacks of screening and its meta-analysisxs. The current American and European screening strategies are described. Nonetheless, PSA is one of the most widely used tumor markers and strongly correlates with the risk of harboring PCa. However, while PSA has limitations for PCa detection with its low specificity there are several potential biomarkers presented in this review with utility for PCa currently being studied. There is an urgent need for new biomarkers especially to detect clinically significant and aggressive PCa. From all PSA-based markers, the FDA-approved prostate health index (phi) shows improved specificity over percent free and total PSA. Another kallikrein panel, 4K, which includes KLK2 has recently shown promise in clinical research studies but has not yet undergone formal validation studies. In urine, prostate cancer gene 3 (PCA3) has also been validated and approved by the FDA for its utility to detect PCa. The potential correlation of PCA3 with cancer aggressiveness requires more clinical studies. The detection of the fusion of androgen-regulated genes with genes of the regulatory transcription factors in tissue of ~50% of all PCa-patients is a milestone in PCa research. A combination of the urinary assays for TMPRSS2:ERG gene fusion and PCA3 shows an improved accuracy for PCa detection. Overall, the field of PCa biomarker discovery is very exciting and prospective.

  2. Amination of activated carbon for enhancing phenol adsorption: Effect of nitrogen-containing functional groups

    NASA Astrophysics Data System (ADS)

    Yang, Guo; Chen, Honglin; Qin, Hangdao; Feng, Yujun

    2014-02-01

    To study the contribution of different nitrogen-containing functional groups to enhancement of phenol adsorption, the aminated activated carbons (AC) were characterized by N2 adsorption/desorption, XPS, Boehm titration, and pH drift method and tested for adsorption behaviors of phenol. Adsorption isotherm fitting revealed that the Langmuir model was preferred for the aminated ACs. The adsorption capacity per unit surface area (qm/SSABET) was linearly correlated with the amount of pyridinic and pyrrolic N, which suggested that these two functional groups played a critical role in phenol adsorption. The enhancement of adsorption capacity was attributed to the strengthened π-π dispersion between phenol and basal plane of AC by pyridinic, pyrrolic N. The adsorption kinetics was found to follow the pseudo-second-order kinetic model, and intraparticle diffusion was one of the rate-controlling steps in the adsorption process.

  3. 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

  4. Evaluation of prostate-specific antigen (PSA) membrane test assays for the forensic identification of seminal fluid.

    PubMed

    Hochmeister, M N; Budowle, B; Rudin, O; Gehrig, C; Borer, U; Thali, M; Dirnhofer, R

    1999-09-01

    Prostate specific antigen (PSA, also known as p30), a glycoprotein produced by the prostatic gland and secreted into seminal plasma, is a marker used for demonstrating the presence of seminal fluid. Methods for the detection of PSA include Ouchterlony double diffusion, crossover electrophoresis, rocket immuno-electrophoresis, radial immunodiffusion, and ELISA. The extremely sensitive ELISA technique can detect PSA in concentrations as low as approximately 4 ng/mL. However, all these techniques are cumbersome and time consuming to perform in forensic laboratories, especially when only a few samples per week are processed. Various membrane tests are currently used in clinical settings to screen a patient's serum for the presence of PSA at levels greater than 4 ng/mL. In this study we evaluated three immunochromatographic PSA membrane tests by analyzing semen stains stored at room temperature for up to 30 years, post-coital vaginal swabs taken at different time after intercourse, semen-free vaginal swabs, and various female and male body fluids, including urine. The data demonstrate that PSA membrane test assays offer the same sensitivity as ELISA-based tests and provide a rapid approach for the forensic identification of seminal fluid. Furthermore, when the supernatant from a DNA extraction is used for the assay, there is essentially no DNA consumption for determining the presence of PSA in a forensic sample.

  5. 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

  6. Decision-Making Processes among Prostate Cancer Survivors with Rising PSA Levels: Results from a Qualitative Analysis1

    PubMed Central

    Shen, Megan Johnson; Nelson, Christian J.; Peters, Ellen; Slovin, Susan F.; Hall, Simon J.; Hall, Matt; Herrera, Phapichaya Chaoprang; Leventhal, Elaine A.; Leventhal, Howard; Diefenbach, Michael A.

    2014-01-01

    Background Prostate cancer survivors with a rising prostate specific antigen (PSA) level have few treatment options, experience a heightened state of uncertainty about their disease trajectory that might include the possibility of cancer metastasis and death, and often experience elevated levels of distress as they have to deal with a disease they thought they had conquered. Guided by self-regulation theory, the present study examined the cognitive and affective processes involved in shared decision making between physician and patients who experience a rising PSA after definitive treatment for prostate cancer. Methods In-depth interviews were conducted with 34 prostate cancer survivors who had been diagnosed with a rising PSA (i.e., biochemical failure) within the past 12 months. Survivors were asked about their experiences and affective responses after being diagnosed with a rising PSA and while weighing potential treatment options. In addition, patients were asked about their decision-making process for the initial prostate cancer treatment. Results Compared to the initial diagnosis, survivors with a rising PSA reported increased negative affect following their diagnosis, concern about the treatability of their disease, increased planning and health behavior change, heightened levels of worry preceding doctor’s appointments (especially prior to the discussion of PSA testing results), and a strong reliance on physicians’ treatment recommendations. Conclusions Prostate cancer survivors’ decision-making processes for the treatment of a rising PSA are markedly different from those of the initial diagnosis of prostate cancer. Because patients experience heightened distress and rely more heavily on their physicians’ recommendations with a rising PSA, interactions with the health care provider provide an excellent opportunity to address and assist patients with managing the uncertainty and distress inherent with rising PSA levels. PMID:25385751

  7. 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.

  8. 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.

  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. Adsorption of hydroxyacetone on pure ice surfaces.

    PubMed

    Petitjean, Mélanie; Darvas, Maria; Picaud, Sylvain; Jedlovszky, Pál; Le Calvé, Stéphane

    2010-12-17

    The adsorption of hydroxyacetone molecules at the surface of ice is investigated by means of flow-tube reactor measurements in the temperature range: 213-253 K. The number of molecules adsorbed per surface unit is conventionally plotted as a function of the absolute gas concentration of hydroxyacetone and is compared to that previously obtained for acetone and ethanol. The enthalpy of adsorption and the monolayer capacity at the ice surface are determined. In addition, molecular dynamics simulations are performed to support the experimental results. However, it is shown that the available interaction potential between hydroxyacetone and ice is not accurate enough to allow a robust detailed analysis of the adsorption process. Finally, a rapid estimation of the hydroxyacetone partitioning between the gas phase and ice shows that in the densest ice clouds, up to 29% of hydroxyacetone could be adsorbed on pure ice surfaces at 203 K.

  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. 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.

  13. Poliovirus Adsorption by 34 Minerals and Soils

    PubMed Central

    Moore, Rebecca S.; Taylor, Dene H.; Sturman, Lawrence S.; Reddy, Michael M.; Fuhs, G. Wolfgang

    1981-01-01

    The adsorption of radiolabeled infectious poliovirus type 2 by 34 well-defined soils and mineral substrates was analyzed in a synthetic freshwater medium containing 1 mM CaCl2 and 1.25 mM NaHCO3 at pH 7. In a model system, adsorption of poliovirus by Ottawa sand was rapid and reached equilibrium within 1 h at 4°C. Near saturation, the adsorption could be described by the Langmuir equation; the apparent surface saturation was 2.5 × 106 plaque-forming units of poliovirus per mg of Ottawa sand. At low surface coverage, adsorption was described by the Freundlich equation. The soils and minerals used ranged from acidic to basic and from high in organic content to organic free. The available negative surface charge on each substrate was measured by the adsorption of a cationic polyelectrolyte, polydiallyldimethylammonium chloride. Most of the substrates adsorbed more than 95% of the virus. In general, soils, in comparison with minerals, were weak adsorbents. Among the soils, muck and Genesee silt loam were the poorest adsorbents; among the minerals, montmorillonite, glauconite, and bituminous shale were the least effective. The most effective adsorbents were magnetite sand and hematite, which are predominantly oxides of iron. Correlation coefficients for substrate properties and virus adsorption revealed that the elemental composition of the adsorbents had little effect on poliovirus uptake. Substrate surface area and pH, by themselves, were not significantly correlated with poliovirus uptake. A strong negative correlation was found between poliovirus adsorption and both the contents of organic matter and the available negative surface charge on the substrates as determined by their capacities for adsorbing the cationic polyelectrolyte, polydiallyldimethylammonium chloride. PMID:6274259

  14. 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

  15. 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.

  16. 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.

  17. Genetic Variants and Family History predict Prostate Cancer similar to PSA

    PubMed Central

    Zheng, S. Lilly; Sun, Jielin; Wiklund, Fredrik; Gao, Zhengrong; Stattin, Pär; Purcell, Lina D.; Adami, Hans-Olov; Hsu, Fang-Chi; Zhu, Yi; Adolfsson, Jan; Johansson, Jan-Erik; Turner, Aubrey R.; Adams, Tamara S.; Liu, Wennuan; Duggan, David; Carpten, John D.; Chang, Bao-Li; Isaacs, William B.; Xu, Jianfeng; Grönberg, Henrik

    2011-01-01

    Purpose While PSA is the best biomarker for predicting prostate cancer, its predictive performance needs to be improved. Results from the Prostate Cancer Prevention Trial (PCPT) revealed the overall performance measured by the areas under curve (AUC) of the receiver operating characteristic (ROC) at 0.68. The goal of the present study is to assess the ability of genetic variants as a PSA independent method to predict prostate cancer risk. Experimental Design We systematically evaluated all prostate cancer risk variants that were identified from genome-wide association studies during the past year in a large population-based prostate cancer case-control study population in Sweden, including 2,893 prostate cancer patients and 1,781 men without prostate cancer. Results Twelve SNPs were independently associated with prostate cancer risk in this Swedish study population. Using a cutoff of any 11 risk alleles or family history, the sensitivity and specificity for predicting prostate cancer were 0.25 and 0.86, respectively. The overall predictive performance of prostate cancer using genetic variants, family history, and age, measured by AUC was 0.65 (95% CI: 0.63–0.66), significantly improved over that of family history and age (0.61%, 95% CI: 0.59–0.62), P = 2.3 × 10−10. Conclusion The predictive performance for prostate cancer using genetic variants and family history is similar to that of PSA. The utility of genetic testing, alone and in combination with PSA levels, should be evaluated in large studies such as the European Randomized Study for Prostate Cancer trial and PCPT. PMID:19188186

  18. Power-free chip enzyme immunoassay for detection of prostate specific antigen (PSA) in serum.

    PubMed

    Adel Ahmed, Heba; Azzazy, Hassan M E

    2013-11-15

    A power-free, portable "Chip EIA" was designed to render the popular Enzyme Linked Immunosorbent Assay (ELISA) more suitable for point-of-care testing. A number of microfluidic platforms have enabled miniaturization of the conventional microtitre plate ELISA, however, they require external pumping systems, valves, and electric power supply. The Chip EIA platform has eliminated the need for pumps and valves through utilizing a simple permanent magnet and magnetic nanoparticles. The magnetic nanoparticles act as solid support to capture the target and are then moved through chambers harboring different reagents necessary to perform a sandwich ELISA. The use of magnetic nanoparticles increases the volume-to-surface ratio reducing the assay time to 30 min. Changing the color of horseradish peroxidase (HRP) substrate to green indicates a positive result. In addition, a quantitative read-out was obtained through the use of cellphone camera imaging and analyzing the images using Matlab®. Cell phones, including smart ones, are readily available almost everywhere. The Chip EIA device was used to assay total prostate specific antigen (tPSA) in 19 serum samples. The PSA Chip EIA was tested for accuracy, precision, repeatability, and the results were correlated to the commercial Beckman Colter, Hybritech immunoassay® for determination of tPSA in serum samples with a Pearson correlation coefficient (R(2)=0.96). The lower detection limit of the PSA Chip EIA was 3.2 ng/mL. The assay has 88.9% recovery and good reproducibility (% CV of 6.5). We conclude that the developed Chip EIA can be used for detection of protein biomarkers in biological specimens.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. Adsorption of antimony onto iron oxyhydroxides: adsorption behavior and surface structure.

    PubMed

    Guo, Xuejun; Wu, Zhijun; He, Mengchang; Meng, Xiaoguang; Jin, Xin; Qiu, Nan; Zhang, Jing

    2014-07-15

    Antimony is detected in soil and water with elevated concentration due to a variety of industrial applications and mining activities. Though antimony is classified as a pollutant of priority interest by the United States Environmental Protection Agency (USEPA) and Europe Union (EU), very little is known about its environmental behavior and adsorption mechanism. In this study, the adsorption behaviors and surface structure of antimony (III/V) on iron oxides were investigated using batch adsorption techniques, surface complexation modeling (SCM), X-ray photon spectroscopy (XPS) and extended X-ray absorption fine structure spectroscopy (EXAFS). The adsorption isotherms and edges indicated that the affinity of Sb(V) and Sb(III) toward the iron oxides depended on the Sb species, solution pH, and the characteristics of iron oxides. Sb(V) adsorption was favored at acidic pH and decreased dramatically with increasing pH, while Sb(III) adsorption was constant over a broad pH range. When pH is higher than 7, Sb(III) adsorption by goethite and hydrous ferric oxide (HFO) was greater than Sb(V). EXAFS analysis indicated that the majority of Sb(III), either adsorbed onto HFO or co-precipitated by FeCl3, was oxidized into Sb(V) probably due to the involvement of O2 in the long duration of sample preservation. Only one Sb-Fe subshell was filtered in the EXAFS spectra of antimony adsorption onto HFO, with the coordination number of 1.0-1.9 attributed to bidentate mononuclear edge-sharing ((2)E) between Sb and HFO.

  4. 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

  5. Management of low risk and low PSA prostate cancer: long term results from the prostate cancer intervention versus observation trial.

    PubMed

    Wilt, Timothy J

    2014-01-01

    Management of localized prostate cancer is controversial due in part to the lack of randomized controlled trial information in men diagnosed with prostate specific antigen (PSA) testing. Men with low risk or low PSA (<10 ng/ml) prostate cancer comprise up to 70 % of men currently diagnosed. Evidence suggests an excellent long-term prognosis with observation though nearly 90 % are treated with surgery (radical prostatectomy), external beam radiation, or brachytherapy. Results from the Prostate cancer Intervention Versus Observation Trial (PIVOT) provide high quality Level 1 evidence that observation compared to surgery results in similar long-term overall and prostate cancer survival, prevention of bone metastases and avoidance of surgery related harms. Combined with emerging evidence from screening, natural history, decision analysis and cost-effectiveness modeling studies, these data demonstrate that observation is the preferred treatment option for men with low risk and possibly low PSA prostate cancer. Recommending against PSA testing or, in men who still desire testing, raising thresholds of PSA values used to define abnormal, lengthening intervals between PSA tests and discontinuing testing in men with a life expectancy less than 15 years will reduce diagnostic and treatment related harms without adversely impacting overall or disease specific mortality and morbidity. PMID:24531789

  6. 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

  7. 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

  8. Robust design of binary countercurrent adsorption separation processes

    SciTech Connect

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

    1993-03-01

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

  9. Prostate Specific Antigen/Solvent Interaction Analysis (PSA/SIA): A Preliminary Evaluation of a New Assay Concept for Detecting Prostate Cancer Using Urinary Samples

    PubMed Central

    Stovsky, Mark; Ponsky, Lee; Vourganti, Srinivas; Stuhldreher, Peter; Siroky, Mike B.; Kipnis, Victor; Fedotoff, Olga; Mikheeva, Larissa; Zaslavsky, Boris; Chait, Arnon; Jones, J. Stephen

    2011-01-01

    Objectives To provide preliminary clinical performance evaluation of a novel CaP assay, PSA/SIA (Solvent Interaction Analysis) that focused on changes to the structure of PSA. Methods 222 men undergoing prostate biopsy for accepted clinical criteria at three sites (University Hospitals Case Medical Center in Cleveland, Cleveland Clinic, and Veterans Administration Boston Healthcare System) were enrolled in IRB approved study. Prior to TRUS guided biopsy, patients received DRE with systematic prostate massage followed by collection of urine. The PSA/SIA assay determined the relative partitioning of heterogeneous PSA isoform populations in urine between two aqueous phases. A structural index, K, whose numerical value is defined as the ratio of the concentration of all PSA isoforms, was determined by total PSA ELISA and used to set a diagnostic threshold for CaP. Performance was assessed using ROC analysis with biopsy as the gold standard. Results Biopsies were pathologically classified as case (malignant, n=100) or control (benign, n=122). ROC performance demonstrated AUC=0.90 for PSA/SIA and 0.58 for serum tPSA. At a cutoff value of K=1.73, PSA/SIA displayed sensitivity=100%, specificity=80.3%, PPV=80.6%, and NPV=100%. No attempt was made in this preliminary study to further control patient population or selection criteria for biopsy, nor did we analytically investigate the type of structural differences in PSA that led to changes in K value. Conclusions PSA/SIA provides ratiometric information independently of PSA concentration. In this preliminary study, analysis of the overall structurally heterogeneous PSA isoform population using the SIA assay showed promising results to be further evaluated in future studies. PMID:21783231

  10. Ozone adsorption on carbon nanoparticles

    NASA Astrophysics Data System (ADS)

    Chassard, Guillaume; Gosselin, Sylvie; Visez, Nicolas; Petitprez, Denis

    2014-05-01

    Carbonaceous particles produced by incomplete combustion or thermal decomposition of hydrocarbons are ubiquitous in the atmosphere. On these particles are adsorbed hundreds of chemical species. Those of great concern to health are polycyclic aromatic hydrocarbons (PAHs). During atmospheric transport, particulate PAHs react with gaseous oxidants. The induced chemical transformations may change toxicity and hygroscopicity of these potentially inhalable particles. The interaction between ozone and carbon particles has been extensively investigated in literature. However ozone adsorption and surface reaction mechanisms are still ambiguous. Some studies described a fast catalytic decomposition of ozone initiated by an atomic oxygen chemisorption followed by a molecular oxygen release [1-3]. Others suggested a reversible ozone adsorption according to Langmuir-type behaviour [4,5]. The aim of this present study is a better understanding of ozone interaction with carbon surfaces. An aerosol of carbon nanoparticles was generated by flowing synthetic air in a glass tube containing pure carbon (primary particles < 50 nm), under magnetic stirring. The aerosol was then mixed with ozone in an aerosol flow tube. Ozone uptake experiments were performed with different particles concentrations with a fixed ozone concentration. The influence of several factors on kinetics was examined: initial ozone concentration, particle size (50 nm ≤ Dp ≤ 200 nm) and competitive adsorption (with probe molecule and water). The effect of initial ozone concentration was first studied. Accordingly to literature, it has been observed that the number of gas-phase ozone molecules lost per unit particle surface area tends towards a plateau for high ozone concentration suggesting a reversible ozone adsorption according to a Langmuir mechanism. We calculated the initial reaction probability between O3 and carbon particles.An initial uptake coefficient of 1.10-4 was obtained. Similar experiments were

  11. 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

  12. Adsorption of Te on Ge(001): Density-functional calculations

    NASA Astrophysics Data System (ADS)

    Çakmak, M.; Srivastava, G. P.; Ellialtıoğlu, Ş.

    2003-05-01

    We present ab initio density-functional calculations for the adsorption of Te on the Ge(001) surface. Various possible adsorption geometries for the 0.5-, 0.8-, 1-, and 2-ML (monolayer) coverages of Te have been investigated. Our results for sub-monolayer coverages confirm earlier results as well as provide some new insight into the adsorption of Te. Furthermore, our results for the 2-ML coverage of Te suggest that the bonding between the overlayer and the substrate has changed significantly. This may provide useful information on possible desorption of Te in the form of strongly bonded Te2 units.

  13. 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

  14. Groundwater Monitoring Report Project Shoal Area, Corrective Action Unit 447

    SciTech Connect

    2008-01-01

    This report presents the 2007 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) at the Project Shoal Area (PSA) Corrective Action Unit (CAU) 447 located in Churchill County, Nevada. Responsibility for the environmental site restoration of the PSA was transferred from the DOE Office of Environmental Management (DOE-EM) to DOE-LM on October 1, 2006. Requirements for CAU 447, as specified in the Federal Facility Agreement and Consent Order (FFACO 2005) entered into by DOE, the U.S. Department of Defense (DOD), and the State of Nevada, includes groundwater monitoring in support of site closure. This is the first groundwater monitoring report prepared by DOE-LM for the PSA.

  15. 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.

  16. The Effect of Increasing Doses of Saw Palmetto Fruit Extract on Serum PSA Levels: Analysis of the CAMUS Randomized Trial

    PubMed Central

    Andriole, Gerald L.; McCullum-Hill, Christie; Sandhu, Gurdarshan S.; Crawford, E. David; Barry, Michael J.; Cantor, Alan

    2014-01-01

    Purpose Saw palmetto extracts are used for treating lower urinary tract symptoms in men despite level I evidence concluding that saw palmetto was ineffective in reducing lower urinary symptoms. We sought to determine whether higher doses of saw palmetto as studied in CAMUS affect serum PSA levels. Materials and Methods The CAMUS trial was a randomized, placebo-controlled double blind multi-centered North American trial conducted between June 5, 2008 and October 10, 2012 in which 369 men >45 years of age with AUA symptom score ≥ 8 and ≤ 24 were randomly assigned to placebo or dose escalation saw palmetto, which consisted of 320mg for first 24 weeks to 640mg for next 24 weeks to 960mg for last 24 weeks of this 72 week trial. Serum PSA levels (Beckman-Coulter) were obtained at baseline and at weeks 24, 48 and 72 and were compared between treatment groups using the pooled t and Fisher's exact tests. Results Serum PSA levels were similar at baseline for the placebo (1.93 ± 1.59 ng/ml) and saw palmetto groups (2.20 ± 1.95, p = 0.16). Changes in PSA levels over the course of the study were similar: placebo group mean change 0.16 ± 1.08 ng/ml and saw palmetto group mean change 0.23 ± 0.83 ng/ml (p value 0.50). Additionally, no differential effect on serum PSA levels was observed between treatment arms when groups were stratified by baseline PSA values. Conclusions Saw palmetto extract does not affect serum PSA levels more than placebo even at relatively high doses. PMID:23253958

  17. 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)

  18. Sulfate adsorption on goethite

    SciTech Connect

    Rietra, R.P.J.J.; Hiemstra, T.; Riemsdijk, W.H. van

    1999-10-15

    Recent spectroscopic work has suggested that only one surface species of sulfate is dominant on hematite. Sulfate is therefore a very suitable anion to test and develop adsorption models for variable charge minerals. The authors have studied sulfate adsorption on goethite covering a large range of sulfate concentrations, surface coverages, pH values, and electrolyte concentrations. Four different techniques were used to cover the entire range of conditions. For characterization at low sulfate concentrations, below the detection limit of sulfate with ICP-AES, the authors used proton-sulfate titrations at constant pH. Adsorption isotherms were studied for the intermediate sulfate concentration range. Acid-base titrations in sodium sulfate and electromobility were used for high sulfate concentrations. All the data can be modeled with one adsorbed species if it is assumed that the charge of adsorbed sulfate is spatially distributed in the interface. The charge distribution of sulfate follows directly from modeling the proton-sulfate adsorption stoichoimemtry sine this stoichiometry is independent of the intrinsic affinity constant of sulfate. The charge distribution can be related to the structure of the surface complex by use of the Pauling bond valence concept and is in accordance with the microscopic structure found by spectroscopy. The intrinsic affinity constant follows from the other measurements. Modeling of the proton-ion stoichoimetry with the commonly used 2-pK models, where adsorbed ions are treated as point charges, is possible only if at least two surface species for sulfate are used.

  19. SEPARATION BY ADSORPTION

    DOEpatents

    Lowe, C.S.

    1959-06-16

    Separation of Pu from fission products by adsorption on hydrous aluminum silicate is described. The Pu in a HNO/sub 3/ solution is oxidized to the hexavalent state and contacted with the silicate which adsorbs fission products. (T.R.H.)

  20. 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

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

    PubMed Central

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

    2009-01-01

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

  2. Treatment of uncertainties in Hanford high-level waste tank PSA modeling

    SciTech Connect

    MacFarlane, D.R.; Stack, D.W. ); Kindinger, J.; Dermrer, R.K.; Medhekar, S.R. ); Yuan, Y.C. )

    1993-01-01

    At the Hanford site, there are 177 underground tanks in 18 separate tank farms. The tanks contain accumulated liquid radioactive wastes from 50 yr of weapons materials production activities. The total volume contained in these tanks is [approximately]60 million gal containing [approximately]500 million Ci of radioactivity. The ultimate objectives of the tank farm probabilistic safety analysis (PSA) are twofold: 1. Develop a baseline estimate of the risks these wastes pose to the workers and the public with their present contents and configurations. 2. Provide a relative ranking of the risks associated with individual tanks and groups of tanks.

  3. 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

  4. Evaluating PSA Density as a Predictor of Biochemical Failure after Radical Prostatectomy: Results of a Prospective Study after a Median Follow-Up of 36 Months

    PubMed Central

    Perimenis, Petros

    2013-01-01

    Purpose. To evaluate the predictive ability of PSA density for biochemical relapse after radical prostatectomy in patients operated for clinically localized disease and to compare its predictive strength with preoperative PSA and Gleason score. Patients and Methods. The study evaluated 244 patients with localized disease who underwent an open retropubic radical prostatectomy between February 2007 and April 2011. PSA was measured every 3 months after surgery with a mean follow-up period of 36 months. Two consecutive rises >0.2 ng/mL were considered as biochemical relapse. Results. Biochemical recurrence was observed in 71 (29.1%). A great correlation was found between relapse and PSA (P = 0.005), PSA density (P = 0.002), Gleason score (P = 0.015), pathological stage (P = 0.001), positive surgical margins (P = 0.021), and invasion of seminal vesicles (P < 0.001) and lymph nodes (P < 0.001). We also found that PSA density was associated with adverse pathological findings. In univariate and multivariate analysis both PSA (P = 0.006) and PSA density (P = 0.009) were found to be significant predictors for relapse in contrast to tumor grade. Conclusion. PSA density is a valuable parameter in estimating the danger of biochemical failure and it may increase predictive potential through the incorporation in preoperative nomograms. PMID:23762630

  5. Carbonaceous materials for adsorptive refrigerators

    NASA Astrophysics Data System (ADS)

    Buczek, B.; Wolak, E.

    2012-06-01

    Carbon monoliths prepared from hard coal precursors were obtained. The porous structure of the monoliths was evaluated on the basis of nitrogen adsorption — desorption equilibrium data. The investigated monoliths have a well-developed microporous structure with significant specific surface area (S BET ). Equilibrium studies of methanol vapour adsorption were used to characterize the methanol adsorptive capacity that was determined using a volumetric method. The heat of wetting by methanol was determined in order to estimate the energetic effects of the adsorption process. The results of the investigations show that all monoliths exhibit high adsorption capacity and high heat of wetting with methanol.

  6. Effect of particle association on 2,2{prime}-bipyridyl adsorption onto kaolinite

    SciTech Connect

    Helmy, A.K.; Ferreiro, E.A.; Bussetti, S.G. de

    2000-05-15

    The effect of particle concentration, in kaolin suspensions, on the adsorption of 2,2{prime}-bipyridyl was studied. Adsorption expressed in units of micromoles per gram decreased as a result of the increase in particle concentration and also as a result of the presence of coagulant (0.25 M NaCl). Dispersion treatment with sodium hexametaphosphate increased the adsorption of bipyridyl. The decrease in adsorption with the increase in particle concentration suggests a possible relation between adsorption and flocculation phenomena. On the basis of classic flocculation theory a straight-line relation was obtained between the square root of the adsorption maximum (mmol/L) and particle concentration (g/L). It is concluded that particle association, which is a function of particle concentration, reduces the surface/aqueous interface and consequently the adsorption of bipyridyl.

  7. 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.

  8. 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

  9. 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

  10. Portable smartphone quantitation of prostate specific antigen (PSA) in a fluoropolymer microfluidic device.

    PubMed

    Barbosa, Ana I; Gehlot, Poonam; Sidapra, Kalpita; Edwards, Alexander D; Reis, Nuno M

    2015-08-15

    We present a new, power-free and flexible detection system named MCFphone for portable colorimetric and fluorescence quantitative sandwich immunoassay detection of prostate specific antigen (PSA). The MCFphone is composed by a smartphone integrated with a magnifying lens, a simple light source and a miniaturised immunoassay platform, the Microcapillary Film (MCF). The excellent transparency and flat geometry of fluoropolymer MCF allowed quantitation of PSA in the range 0.9 to 60 ng/ml with<7% precision in 13 min using enzymatic amplification and a chromogenic substrate. The lower limit of detection was further improved from 0.4 to 0.08 ng/ml in whole blood samples with the use of a fluorescence substrate. The MCFphone has shown capable of performing rapid (13 to 22 min total assay time) colorimetric quantitative and highly sensitive fluorescence tests with good %Recovery, which represents a major step in the integration of a new generation of inexpensive and portable microfluidic devices with commercial immunoassay reagents and off-the-shelf smartphone technology.

  11. Portable smartphone quantitation of prostate specific antigen (PSA) in a fluoropolymer microfluidic device.

    PubMed

    Barbosa, Ana I; Gehlot, Poonam; Sidapra, Kalpita; Edwards, Alexander D; Reis, Nuno M

    2015-08-15

    We present a new, power-free and flexible detection system named MCFphone for portable colorimetric and fluorescence quantitative sandwich immunoassay detection of prostate specific antigen (PSA). The MCFphone is composed by a smartphone integrated with a magnifying lens, a simple light source and a miniaturised immunoassay platform, the Microcapillary Film (MCF). The excellent transparency and flat geometry of fluoropolymer MCF allowed quantitation of PSA in the range 0.9 to 60 ng/ml with<7% precision in 13 min using enzymatic amplification and a chromogenic substrate. The lower limit of detection was further improved from 0.4 to 0.08 ng/ml in whole blood samples with the use of a fluorescence substrate. The MCFphone has shown capable of performing rapid (13 to 22 min total assay time) colorimetric quantitative and highly sensitive fluorescence tests with good %Recovery, which represents a major step in the integration of a new generation of inexpensive and portable microfluidic devices with commercial immunoassay reagents and off-the-shelf smartphone technology. PMID:25775968

  12. Core melt progression and consequence analysis methodology development in support of the Savannah River Reactor PSA

    SciTech Connect

    O'Kula, K.R.; Sharp, D.A. ); Amos, C.N.; Wagner, K.C.; Bradley, D.R. )

    1992-01-01

    A three-level Probabilistic Safety Assessment (PSA) of production reactor operation has been underway since 1985 at the US Department of Energy's Savannah River Site (SRS). The goals of this analysis are to: Analyze existing margins of safety provided by the heavy-water reactor (HWR) design challenged by postulated severe accidents; Compare measures of risk to the general public and onsite workers to guideline values, as well as to those posed by commercial reactor operation; and Develop the methodology and database necessary to prioritize improvements to engineering safety systems and components, operator training, and engineering projects that contribute significantly to improving plant safety. PSA technical staff from the Westinghouse Savannah River Company (WSRC) and Science Applications International Corporation (SAIC) have performed the assessment despite two obstacles: A variable baseline plant configuration and power level; and a lack of technically applicable code methodology to model the SRS reactor conditions. This paper discusses the detailed effort necessary to modify the requisite codes before accident analysis insights for the risk assessment were obtained.

  13. False positives observed on the Seratec® PSA SemiQuant Cassette Test with condom lubricants.

    PubMed

    Bitner, Sara E

    2012-11-01

    In the course of the validation of a new component of the prostate-specific antigen (PSA) SemiQuant Cassette Test marketed by Seratec(®) , a false-positive reaction was observed when testing samples collected from the surface of unused, lubricated condoms. A variety of personal lubricants and condoms were tested to determine the frequency of the false positive, as well as its potential source. Samples were extracted in both water and the manufacturer-provided buffer, and the test was performed according to the manufacturer's suggested protocol. The false positive was observed intermittently, but occurred consistently with samples containing nonoxynol-9, a strong detergent utilized as a spermicide. The reaction may be attributable to the combination of latex and nonoxynol-9. Because of the unreliability of the test to confirm the presence of PSA in samples collected from condoms, the PSA cassette is an unsuitable method for confirming the presence of seminal fluid in condoms. PMID:22494324

  14. 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.

  15. Adsorption edge study about cadmium, copper, nickel and zinc adsorption by variable charge soils

    NASA Astrophysics Data System (ADS)

    Casagrande, J. C.; Mouta, E. R.; Soares, M. R.

    2009-04-01

    The improper discharge of industrial and urban residues and the inadvertent use of fertilizers and pesticides can result in soil and water pollution and improve the potential of trace metals to enter in the human food chain. Adsorption reactions occur at the solid/liquid interface and are the most important mechanisms for controlling the activity of metal ions in soil solution. In a complex system with amphoteric behavior, the comprehension of the mobility, availability and fate of pollutants in the soil system is crucial for the prediction of the environmental consequences and for development of prevention/remediation strategies. A comparative study of cadmium (Cd), copper (Cu), nickel (Ni) and zinc (Zn) adsorption by highly weathered soils was carried out. Surface (0-0.2m) and subsoil (B horizon) samples were taken from a Rhodic Kandiudalf (RH), an Anionic "Xanthic" Acrudox (XA) and an Anionic "Rhodic" Acrudox (RA), located in brazilian humid tropical area. As the pH and the ionic strength are important environmental factors influencing the solution chemistry of heavy metals in variable charge systems, adsorption envelopes, in a batch adsorption experiment, were elaborated by reacting, for 24 h, soil samples with individual 0.01, 0.1 and 1.0 mol L-1 Ca(NO3)2 aqueous solutions containing nitrate salts of the adsorptive heavy metal (Cd, Cu, Ni and Zn) at the initial concentration of 5 mg L-1, with an increasing pH value from 3.0 to 8.0. pH50-100%, the difference between the pH of 100 and 50 percent metal adsorption was determined. A sharp increase of adsorption density (adsorption edge) was observed within a very narrow pH range, usually less than two pH units. Commonly, the relative affinity of a soil for a metal cation increases with the tendency of the cation to form inner-sphere surface complexes. This may be caused by differences in extent of hydrolysis of Cu ions and in affinity of adsorption sites for Cu. In general, subsurface samples showed low pH50

  16. Physical Characterization of the Manganese-sensing Pneumococcal Surface Antigen Repressor (PsaR) from Streptococcus pneumoniae*

    PubMed Central

    Lisher, John P.; Higgins, Khadine A.; Maroney, Michael J.; Giedroc, David P.

    2013-01-01

    Transition metals, including manganese, are required for proper virulence and persistence of many pathogenic bacteria. In Streptococcus pneumoniae (Spn), manganese homeostasis is controlled by a high affinity Mn(II) uptake complex, PsaBCA, and a constitutively expressed efflux transporter, MntE. PsaBCA expression is transcriptionally regulated by the DtxR/MntR family metalloregulatory protein pneumococcal surface antigen repressor (PsaR) in Spn. Here, we present a comprehensive analysis of the metal and DNA-binding properties of PsaR. PsaR is a homodimer in the absence and presence of metals and binds two manganese or zinc per protomer (four per dimer) in two pairs of structurally distinct sites, termed site 1 and site 2. Site 1 is likely filled with Zn(II) in vivo (KZn1≥1013 M−1; KMn1≈108 M−1). The Zn(II)-site 1 complex adopts a pentacoordinate geometry by x-ray absorption spectroscopy containing a single cysteine, and appears analogous to the Cd(II) site observed in S. gordonii ScaR. Site 1 is necessary but not sufficient for full positive allosteric activation of DNA operator binding by metals as measured by ΔGc, the allosteric coupling free energy, since mutants in site 1 show intermediate ΔGc. Site 2 is the primary regulatory site and governs specificity for Mn(II) over Zn(II) in PsaR, with ΔGcZn,Mn>>ΔGcZn,Zn despite the fact that Zn(II) binds site 2 with 40-fold higher affinity relative to Mn(II), i.e., KZn2>KMn2. Mutational studies reveal that Asp7 in site 2 is a critical ligand for Mn(II)-dependent allosteric activation of DNA binding. These findings are discussed in the context of other well-studied DtxR/MntR Mn(II)/Fe(II) metallorepressors. PMID:24067066

  17. A Common Model to Handle PDS3 and PDS4 Data in the New Planetary Science Archive (PSA)

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    The first of the European Space Agency's (ESA) planetary missions to make use of the latest release of the Planetary Data Standards (PDS4) are currently in advanced stages of development (ExoMars, BepiColombo). This occurs at a time when the Planetary Science Archive (PSA) has been undergoing a complete reengineering in order to increase the accessibility of ESA's planetary data holdings utilising the latest technologies and to significantly improve the user experience for both the specialist scientific community and general public alike. The PSA must also keep on handling PDS3 data arriving to the archive from active missions (Rosetta, Mars Express, Venus Express) as well as continuing to provide access to missions that have reached the legacy phase (Huygens, SMART1, Giotto). Therefore, as part of the reengineering of the PSA, an effort has been made to map the key metadata from PDS3 and PDS4 into a common data model with the intention of providing transparency to the services that make up the new PSA, and consequently to the end user. We present how this common mapping allows the PSA to support the data deliveries from the pipelines of existing missions without the need to reprocess the PDS3 data and in addition how it should simplify the data deliveries from PDS4 missions. We review how the implementation of this data model, involving a PostgreSQL database with the PostGIS extension, enables the new PSA to be able to provide multiple methods of interoperability used by the international community, such as PDAP (Planetary Data Access Protocol), EPN-TAP (EuroPlanet-Table Access Protocol), and GIS-enabled technologies without the user having to know in detail the underlying structure of the data format.

  18. Carbon adsorption system protects LPG storage sphere

    SciTech Connect

    Gothenquist, C.A.; Rooker, K.M.

    1996-07-01

    Chevron U.S.A. Products Co. installed a carbon adsorption system to protect an LPG storage sphere at its refinery in Richmond, Calif. Vessel damage can result when amine contamination leads to emulsion formation and consequent amine carry-over, thus promoting wet-H{sub 2}S cracking. In Chevron`s No. 5 H{sub 2}S recovery plant, a mixture of butane and propane containing H{sub 2}S is contacted with diethanolamine (DEA) in a liquid-liquid absorber. The absorber is a countercurrent contactor with three packed beds. Because the sweetening system did not include a carbon adsorption unit for amine purification, contaminants were building up in the DEA. The contaminants comprised: treatment chemicals, hydrocarbons, foam inhibitors, and amine degradation products. The paper describes the solution to this problem.

  19. Very Early PSA Response to Abiraterone in mCRPC Patients: A Novel Prognostic Factor Predicting Overall Survival

    PubMed Central

    Facchini, Gaetano; Caffo, Orazio; Ortega, Cinzia; D'Aniello, Carmine; Di Napoli, Marilena; Cecere, Sabrina C.; Della Pepa, Chiara; Crispo, Anna; Maines, Francesca; Ruatta, Fiorella; Iovane, Gelsomina; Pisconti, Salvatore; Montella, Maurizio; Berretta, Massimiliano; Pignata, Sandro; Cavaliere, Carla

    2016-01-01

    Background: Abiraterone Acetate (AA) is approved for the treatment of mCRPC after failure of androgen deprivation therapy in whom chemotherapy is not yet clinically indicated and for treatment of mCRPC progressed during or after docetaxel-based chemotherapy regimen. The aim of this study is to evaluate the role of early PSA decline for detection of therapy success or failure in mCRPC patients treated with AA in post chemotherapy setting. Patients and Methods: We retrospectively evaluated 87 patients with mCRPC treated with AA. Serum PSA levels were evaluated after 15, 90 days and then monthly. The PSA flare phenomenon was evaluated, according to a confirmation value at least 1 week apart. The primary endpoint was to demonstrate that an early PSA decline correlates with a longer progression free survival (PFS) and overall survival (OS). The secondary endpoind was to demonstrate a correlation between better outcome and demographic and clinical patient characteristics. Results: We have collected data of 87 patients between Sep 2011 and Sep 2014. Early PSA response (≥50% from baseline at 15 days) was found in 56% evaluated patients and confirmed in 29 patients after 90 days. The median PFS was 5.5 months (4.6–6.5) and the median OS was 17.1 months (8.8–25.2). In early responders patients (PSA RR ≥ 50% at 15 days), we found a significant statistical advantage in terms of PFS at 1 year, HR 0.28, 95%CI 0.12–0.65, p = 0.003, and OS, HR 0.21 95% CI 0.06–0.72, p = 0.01. The results in PFS at 1 years and OS reached statistical significance also in the evaluation at 90 days. Conclusion: A significant proportion (78.6%) of patients achieved a rapid response in terms of PSA decline. Early PSA RR (≥50% at 15 days after start of AA) can provide clinically meaningful information and can be considered a surrogate of longer PFS and OS. PMID:27242530

  20. Development, Construction, and Operation of a Multisample Volumetric Apparatus for the Study of Gas Adsorption Equilibrium

    ERIC Educational Resources Information Center

    Ribeiro, Rui P. P. L.; Silva, Ricardo J. S.; Esteves, Isabel A. A. C.; Mota, Jose´ P. B.

    2015-01-01

    The construction of a simple volumetric adsorption apparatus is highlighted. The setup is inexpensive and provides a clear demonstration of gas phase adsorption concepts. The topic is suitable for undergraduate chemistry and chemical engineering students. Moreover, this unit can also provide quantitative data that can be used by young researchers…

  1. Plasma Carotenoids and Tocopherols in Relation to Prostate-specific Antigen (PSA) Levels Among Men with Biochemical Recurrence of Prostate Cancer

    PubMed Central

    Antwi, Samuel; Steck, Susan E.; Zhang, Hongmei; Stumm, Lareissa; Zhang, Jiajia; Hurley, Thomas G.; Hebert, James R.

    2015-01-01

    Background Although men presenting with clinically localized prostate cancer (PrCA) often are treated with radical prostatectomy or radiation therapy with curative intent, about 25–40% develop biochemically recurrent PrCA within 5 years of treatment, which has no known cure. Studies suggest that carotenoid and tocopherol intake may be associated with PrCA risk and progression. We examined plasma carotenoid and tocopherol levels in relation to prostate-specific antigen (PSA) levels among men with PSA-defined biochemical recurrence of PrCA. Methods Data analyzed were from a 6-month diet, physical activity and stress-reduction intervention trial conducted in South Carolina among biochemically recurrent PrCA patients (n=39). Plasma carotenoids and tocopherol levels were measured using high-performance liquid chromatography (HPLC). Linear regression was used to estimate least-square means comparing PSA levels of men with high versus low carotenoid/tocopherol levels, adjusting for covariates. Results After adjusting for baseline PSA level, plasma cis-lutein/zeaxanthin level at 3 months was related inversely to PSA level at 3 months (P=0.0008), while α-tocopherol (P=0.01), β-cryptoxanthin (P=0.01), and all-trans-lycopene (P=0.004) levels at 3 months were related inversely to PSA levels at 6-months. Percent increase in α-tocopherol and trans-β-carotene levels from baseline to month 3 were associated with lower PSA levels at 3 and 6 months. Percent increase in β−cryptoxanthin, cislutein/zeaxanthin and all-trans-lycopene were associated with lower PSA levels at 6 months only. Conclusions Certain plasma carotenoids and tocopherols were related inversely to PSA levels at various timepoints, suggesting that greater intake of foods containing these micronutrients might be beneficial to men with PSA-defined PrCA recurrence. PMID:26165176

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

    PubMed

    Afonso, R; Mendes, A; Gales, L

    2014-09-28

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

  3. Joint enhancement strategy applied in ECL biosensor based on closed bipolar electrodes for the detection of PSA.

    PubMed

    Shi, Hai-Wei; Zhao, Wei; Liu, Zhen; Liu, Xi-Cheng; Wu, Mei-Sheng; Xu, Jing-Juan; Chen, Hong-Yuan

    2016-07-01

    A highly sensitive electrogenerated chemiluminescence (ECL) biosensor was developed on the basis of a closed bipolar electrode (BPE) apparatus for the analysis of prostate specific antigen (PSA). Bipolar modifications bring up two different stages of enhancement on the same electrode. Anodic enhancement was conducted by modifying gold nanoparticles (Au NPs) to catalyze the anodic ECL reaction between luminol and hydrogen peroxide. Cathodic introduction of thionine tagged PSA antibody led to a further pertinently enhancement synchronized with the PSA amount variation, because the existence of thionine greatly increased the rate of electron gains on cathode, leading to the corresponding acceleration of anodic ECL reaction. The more thionine modified target molecules were introduced, the faster luminol was oxidized, the higher faraday current approached, and sensitive quantification was realized in correlation with the responsive ECL intensity differences. The quantification resulted in a good determination range between 0.1pg/mL and 0.1µg/mL. This strategy mainly took advantage of the special structure of closed BPE to realize a simultaneous amplification on both ends of BPE. Moreover, the platform had a potential of providing a multi-functional strategy for the realization of other bio-detections by simply substituting the PSA sandwich structure with other bio-structures. PMID:27154662

  4. Promotion of cell migration by neural cell adhesion molecule (NCAM) is enhanced by PSA in a polysialyltransferase-specific manner.

    PubMed

    Guan, Feng; Wang, Xin; He, Fa

    2015-01-01

    Neural cell adhesion molecule 140 (NCAM-140) is a glycoprotein and always highly polysialylated in cancer. Functions of polysialic acid (PSA) that binds to N-glycan termini on NCAM remain unclear. ldlD-14 cells, a CHO cell mutant deficient in UDP-Gal 4-epimerase, are useful for structural and functional studies of Gal-containing glycoproteins because their abnormal glycosylation can be converted to normal status by exogenous addition of galactose (Gal). We cloned the genes for NCAM-140 and for polysialyltransferases STX and PST (responsible for PSA synthesis) from normal murine mammary gland epithelial (NMuMG) cells and transfected them into ldlD-14 and human breast cancer cells MCF-7. The effect of PSA on NCAM-mediated cell proliferation, motility, migration and adhesion was studied. We found that NCAM-140 significantly promoted cell proliferation, motility and migration, while polysialylation of NCAM-140 catalyzed by STX, but not by PST, enhanced NCAM-mediated cell migration, but not cell proliferation or motility. In addition, PSA catalyzed by different polysialyltransferases affected the adhesion of NCAM to different extracellular matrix (ECM) components. PMID:25885924

  5. Signal amplification strategy for sensitive immunoassay of prostate specific antigen (PSA) based on ferrocene incorporated polystyrene spheres.

    PubMed

    Ding, Lu; You, Jinmao; Kong, Rongmei; Qu, Fengli

    2013-09-01

    A new kind of signal amplification strategy based on ferrocene (Fc) incorporated polystyrene spheres (PS-Fc) was proposed. The synthesized PS-Fc displayed narrow size distribution and good stability. PS-Fc was applied as label to develop immunosensors for prostate specific antigen (PSA) after the typical sandwich immunoreaction by linking anti-PSA antibody (Ab2) onto PS-Fc. After the fabrication of the immunosensor, tetrahydrofuran (THF) was dropped to dissolve PS and release the contained Fc for the following stripping voltammetric detection. PS-Fc as a new electrochemical label prevented the leakage of Fc and greatly amplified the immunosensor signal. In addition, the good biocompatibility of PS could maintain the bioactivity of the antibodies. The response current was linear to the logarithm of PSA concentration in the range from 0.01 ng mL(-1) to 20 ng mL(-1) with a detection limit of 1 pg mL(-1). The immunosensor results were validated through the detection of PSA in serum samples with satisfactory results.

  6. Análisis del antígeno prostático específico (PSA)

    Cancer.gov

    Hoja informativa sobre la prueba del antígeno prostático específico (PSA) y los exámenes selectivos de detección para el cáncer de próstata, y clarifica los beneficios y limitaciones de dicha prueba.

  7. A Comparison of the Prognostic Value of Early PSA Test-Based Variables Following External Beam Radiotherapy, With or Without Preceding Androgen Deprivation: Analysis of Data From the TROG 96.01 Randomized Trial

    SciTech Connect

    Lamb, David S.; Denham, James W.; Joseph, David; Matthews, John; Atkinson, Chris; Spry, Nigel A.; Duchesne, Gillian; Ebert, Martin; Steigler, Allison; Delahunt, Brett; D'Este, Catherine

    2011-02-01

    Purpose: We sought to compare the prognostic value of early prostate-specific antigen (PSA) test-based variables for the 802 eligible patients treated in the Trans-Tasman Radiation Oncology Group 96.01 randomized trial. Methods and Materials: Patients in this trial had T2b, T2c, T3, and T4 N0 prostate cancer and were randomized to 0, 3, or 6 months of neoadjuvant androgen deprivation therapy (NADT) prior to and during radiation treatment at 66 Gy to the prostate and seminal vesicles. The early PSA test-based variables evaluated were the pretreatment initial PSA (iPSA) value, PSA values at 2 and 4 months into NADT, the PSA nadir (nPSA) value after radiation in all patients, and PSA response signatures in men receiving radiation. Comparisons of endpoints were made using Cox models of local progression-free survival, distant failure-free survival, biochemical failure-free survival, and prostate cancer-specific survival. Results: The nPSA value was a powerful predictor of all endpoints regardless of whether NADT was given before radiation. PSA response signatures also predicted all endpoints in men treated by radiation alone. iPSA and PSA results at 2 and 4 months into NADT predicted biochemical failure-free survival but not any of the clinical endpoints. nPSA values correlated with those of iPSA, Gleason grade, and T stage and were significantly higher in men receiving radiation alone than in those receiving NADT. Conclusions: The postradiation nPSA value is the strongest prognostic indicator of all early PSA-based variables. However, its use as a surrogate endpoint needs to take into account its dependence on pretreatment variables and treatment method.

  8. Cd adsorption onto bacterial surfaces: A universal adsorption edge?

    NASA Astrophysics Data System (ADS)

    Yee, Nathan; Fein, Jeremy

    2001-07-01

    In this study, we measure the thermodynamic stability constants for proton and Cd binding onto the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and the Gram-positive bacteria Bacillus megaturium, Streptococcus faecalis, Staphylococcus aureus, Sporosarcina ureae, and Bacillus cereus. Potentiometric titrations and Cd-bacteria adsorption experiments yield average values for the carboxyl site pK a, site concentration, and log stability constant for the bacterial surface Cd-carboxyl complex of 5.0, 2.0 × 10 -3 mol/g and 4.0 respectively. Our results indicate that a wide range of bacterial species exhibit nearly identical Cd adsorption behavior as a function of pH. We propose that metal-bacteria adsorption is not dependent on the bacterial species involved, and we develop a generalized adsorption model which may greatly simplify the task of quantifying the effects of bacterial adsorption on dissolved mass transport in realistic geologic systems.

  9. 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.

  10. 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.

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

    SciTech Connect

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

    2009-01-01

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

  12. A randomized phase II study of pomegranate extract for men with rising PSA following initial therapy for localized prostate cancer

    PubMed Central

    Paller, CJ; Ye, X; Wozniak, PJ; Gillespie, BK; Sieber, PR; Greengold, RH; Stockton, BR; Hertzman, BL; Efros, MD; Roper, RP; Liker, HR; Carducci, MA

    2012-01-01

    BACKGROUND Pomegranate juice has been associated with PSA doubling time (PSADT) elongation in a single-arm phase II trial. This study assesses biological activity of two doses of pomegranate extract (POMx) in men with recurrent prostate cancer, using changes in PSADT as the primary outcome. METHODS This randomized, multi-center, double-blind phase II, dose-exploring trial randomized men with a rising PSA and without metastases to receive 1 or 3 g of POMx, stratified by baseline PSADT and Gleason score. Patients (104) were enrolled and treated for up to 18 months. The intent-to-treat (ITT) population was 96% white, with median age 74.5 years and median Gleason score 7. This study was designed to detect a 6-month on-study increase in PSADT from baseline in each arm. RESULTS: Overall, median PSADT in the ITT population lengthened from 11.9 months at baseline to 18.5 months after treatment (P<0.001). PSADT lengthened in the low-dose group from 11.9 to 18.8 months and 12.2 to 17.5 months in the high-dose group, with no significant difference between dose groups (P =0.554). PSADT increases >100% of baseline were observed in 43% of patients. Declining PSA levels were observed in 13 patients (13%). In all, 42% of patients discontinued treatment before meeting the protocol-definition of PSA progression, or 18 months, primarily due to a rising PSA. No significant changes occurred in testosterone. Although no clinically significant toxicities were seen, diarrhea was seen in 1.9% and 13.5% of patients in the 1- and 3-g dose groups, respectively. CONCLUSIONS POMx treatment was associated with ≥6 month increases in PSADT in both treatment arms without adverse effects. The significance of this on-study slowing of PSADT remains unclear, reinforcing the need for placebo-controlled studies in this patient population. PMID:22689129

  13. PSA Bounce and Biochemical Failure After Brachytherapy for Prostate Cancer: A Study of 820 Patients With a Minimum of 3 Years of Follow-Up

    SciTech Connect

    Caloglu, Murat; Ciezki, Jay P.; Reddy, Chandana A.; Angermeier, Kenneth; Ulchaker, James; Chehade, Nabil; Altman, Andrew; Magi-Galuzzi, Christina; Klein, Eric A.

    2011-07-01

    Purpose: To determine clinical or dosimetric factors associated with a prostate-specific antigen (PSA) bounce, as well as an association between a PSA bounce and biochemical relapse-free survival (bRFS), in patients treated with iodine-125 brachytherapy. Methods and Materials: A variety of clinical and treatment factors were examined in 820 patients who had a minimum of 3 years of PSA follow-up with T1-T2cN0M0 prostate cancer. Four different PSA threshold values were used for defining a PSA bounce: a PSA rise of {>=}0.2, {>=}0.4, {>=}0.6, and {>=}0.8 ng/mL. Results: A PSA bounce of {>=}0.2, {>=}0.4, {>=}0.6, and {>=}0.8 ng/mL was noted in 247 patients (30.1%), 161 (19.6%), 105 (12.8%), and 78 (9.5%), respectively. The median time to the first PSA rise was 17.4, 16.25, 16.23, and 15.71 months, respectively, vs. 34.35 months for a biochemical failure (p < 0.0001). A PSA rise of {>=}0.2 ng/mL was the only definition for which there was a significant difference in bRFS between bounce and non-bounce patients. The 5-year bRFS rate of patients having a PSA bounce of {>=}0.2 was 97.7% vs. 91% for those who did not have a PSA bounce (p = 0.0011). On univariate analysis for biochemical failure, age, risk group, and PSAs per year had a statistically significant correlation with PSA bounce of {>=}0.2 ng/mL. On multivariate analysis, age and PSAs per year remained statistically significant (p < 0.0001 and p = 0.0456, respectively). Conclusions: A bounce definition of a rise {>=}0.2 ng/mL is a reliable definition among several other definitions. The time to first PSA rise is the most valuable factor for distinguishing between a bounce and biochemical failure.

  14. 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.

  15. Design method for adsorption beds

    NASA Technical Reports Server (NTRS)

    Blakely, R. L.; Jackson, J. K.

    1970-01-01

    Regenerable adsorption beds for long-term life support systems include synthetic geolite to remove carbon dioxide and silica gel to dehumidify the atmospheric gas prior to its passage through the geolite beds. Bed performance is evaluated from adsorption characteristics, heat and mass transfer, and pressure drop.

  16. 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.

  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. Critical analysis of the apoferritin adsorption at solid-liquid interfaces in the framework of a particular adsorption model

    NASA Astrophysics Data System (ADS)

    Lavalle, Ph.; Gergely, C.; Lustig, A.; Ball, V.

    2000-11-01

    The adsorption mechanism of horse spleen apoferritin on smooth Si(Ti)O2 surfaces was investigated by means of optical wave guide lightmode spectroscopy (OWLS) as well as with atomic force microscopy (AFM), for which images of high resolution were obtained on muscovite mica surfaces. By the use of both experimental methods, the adsorption process could be studied from a kinetic as well as from a statistical thermodynamics point of view. This approach allowed to test the hypothesis of the occurrence of a particular type of deposition mechanism, namely the random sequential adsorption (RSA), by evaluating all the requirements that should be fulfilled in such a process. Only the requirement relative to the kinetics of the adsorption process, and subsequently, the estimation of the surface coverage at saturation is fulfilled by our experiments. From the fit of the theoretical kinetic equations corresponding to the RSA model to the experimental adsorption kinetics we find that the apoferritin molecules occupy an area of 140±30 nm2, in agreement with the values found by counting the number of particles per unit area in the AFM experiments and also with the saturation level of the adsorption isotherm. From our experiments we found that the evolution of the surface coverage close to saturation did not follow the expected power law evolution with time in the framework of the RSA model. Moreover, the dependence of the density fluctuations on the sub-surface area in the AFM image is not consistent with the expected evolution obtained by computer simulations based on the RSA model. These results emphasize the difficulty to study the adsorption mechanism of proteins at solid—liquid interfaces in the framework of any given adsorption model.

  19. Treatment persistence among patients with rheumatoid disease (RA, AS, PsA) treated with subcutaneous biologics in Germany.

    PubMed

    Lyu, Ramon; Govoni, Marinella; Ding, Qian; Black, Christopher M; Kachroo, Sumesh; Fan, Tao; Ogbonnaya, Augstina; Donga, Prina; Hill, Jerrold; Makin, Charles

    2016-01-01

    Patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS), and psoriatic arthritis (PsA) are frequently treated with subcutaneous biologic therapies when disease progresses or when response to synthetic disease-modifying antirheumatic drugs (DMARDs) is inadequate. This study analyzed treatment persistence and treatment patterns for RA, AS, and PsA patients in Germany initiating subcutaneous biologic therapies with and without prior DMARDs use. A retrospective cohort study was conducted using the Electronic Medical Record database of IMS Disease Analyzer, Germany. Patients who were ≥18 years old; had at least one ICD-10 diagnosis code of RA, AS, or PsA during the study period; and had exposure to a subcutaneous biologic agent between January 1, 2009 and June 30, 2012 were selected. Patients were required to have continuous observation ≥12 months prior to and after index medication date. Persistence was defined as consecutive days from treatment initiation until treatment discontinuation (≥60-day lapse in medication coverage). Patients were stratified by pre-index use of DMARDs. Kaplan-Meier analysis was conducted to assess time to discontinuation, and logistic regression was conducted to identify characteristics associated with persistence. A total of 576 RA, 108 AS, and 197 PsA patients without biologic experience during the pre-index period were selected. The percentages of RA, AS, and PsA patients persistent ≥12 months were 51.9, 48.1, and 57.9 %, respectively. Median persistent time over 12 months was 365.0 days for RA (mean 245.9 days), 281.0 for AS (mean 228.5), and 365.0 for PsA (mean 264.1). In the RA cohort, a significantly higher proportion of those with pre-index DMARD use were persistent compared to those without pre-index DMARD (56.1 vs. 33.3 %, p = 0.0001). No significant differences were observed for the AS and PsA cohorts. Multivariate analyses confirmed that DMARD-experienced patients were 2.45 times more likely to be persistent

  20. 3D MR-Spectroscopic Imaging Assessment of Metabolic Activity in the Prostate During the PSA 'Bounce' Following {sup 125}Iodine Brachytherapy

    SciTech Connect

    Kirilova, Anna; Damyanovich, Andrei; Crook, Juanita; Jezioranski, John; Wallace, Kris; Pintilie, Melania

    2011-02-01

    Purpose: A temporary increase in prostate-specific antigen (PSA) values is observed in 30%-40% of men following {sup 125} I brachytherapy (BT) for prostate cancer. We present the results of a study to characterize prostate metabolic activity during the PSA 'bounce' and to correlate metabolic changes with PSA levels using three-dimensional magnetic resonance spectroscopic imaging (3D-MRSI). Methods and Materials: 3D-MRSI was performed in 24 patients during the PSA bounce. Eight of these had also had a baseline 3D-MRSI scan before BT for the purpose of tumor mapping. The 3D-MRSI was repeated at 6- and 12-month intervals, and PSA levels were monitored every 3 months. Twenty-one of the patients had favorable-risk prostate cancer, and 3 had intermediate risk. Results: The choline+creatine signal intensity, although markedly reduced, was observable following BT. Diffuse activity not corresponding to original biopsy-positive sites was observed in 22 cases, and 2 cases were documented to have local recurrence. No statistically significant correlation between metabolic activity and PSA levels at each interval was found. Conclusion: Post-BT prostate 3D-MRSI shows evidence of diffuse metabolic activity unrelated to residual malignancy. This supports the benign nature of the PSA bounce and suggests an inflammatory etiology. In the situation of a rising PSA, observation of focal activity on MRI/3D-MRSI could be a useful adjunct to suggest local recurrence at an earlier interval after brachytherapy when prostate biopsies would still be unhelpful. Longer follow-up is necessary to confirm the complex relationship between metabolic activity and PSA levels.

  1. 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.

  2. Critical adsorption and colloidal interaction in binary liquid mixtures

    NASA Astrophysics Data System (ADS)

    Alam, Sharmine; Omari, Rami; Grabowski, Christopher; Mukhopadhyay, Ashis

    2015-03-01

    We studied critical adsorption on colloidal nanoparticles in binary liquid mixture of 2,6 lutidine + water by using fluorescence correlation spectroscopy (FCS). Our results indicated that the adsorbed film thickness is of the order of correlation length associated with concentration fluctuations. The excess adsorption per unit area increases following a power law in reduced temperature with an exponent of -1, which is the mean-field value for the bulk susceptibility exponent. The measurements at higher particle volume fractions, where particle-particle interaction becomes important, will be presented. Acknowledgements are made to the Donors of the American Chemical Society Petroleum Research fund (PRF # 51694-ND10) for support of this research.

  3. Prostate-Specific Antigen (PSA)–Based Population Screening for Prostate Cancer: An Evidence-Based Analysis

    PubMed Central

    Pron, G

    2015-01-01

    Background Prostate cancer (PC) is the most commonly diagnosed non-cutaneous cancer in men and their second or third leading cause of cancer death. Prostate-specific antigen (PSA) testing for PC has been in common practice for more than 20 years. Objectives A systematic review of the scientific literature was conducted to determine the effectiveness of PSA-based population screening programs for PC to inform policy decisions in a publicly funded health care system. Data Sources A systematic review of bibliographic databases was performed for systematic reviews or randomized controlled trials (RCT) of PSA-based population screening programs for PC. Review Methods A broad search strategy was employed to identify studies reporting on key outcomes of PC mortality and all-cause mortality. Results The search identified 5 systematic reviews and 6 RCTs. None of the systematic reviews found a statistically significant reduction in relative risk (RR) of PC mortality or overall mortality with PSA-based screening. PC mortality reductions were found to vary by country, by screening program, and by age of men at study entry. The European Randomized Study of Screening for Prostate Cancer found a statistically significant reduction in RR in PC mortality at 11-year follow-up (0.79; 95% CI, 0.67–0.92), although the absolute risk reduction was small (1.0/10,000 person-years). However, the primary treatment for PCs differed significantly between countries and between trial arms. The American Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) found a statistically non-significant increase in RR for PC mortality with 13-year follow-up (1.09; 95% CI, 0.87–1.36). The degree of opportunistic screening in the control arm of the PLCO trial, however, was high. None of the RCTs found a reduction in all-cause mortality and all found a statistically significant increase in the detection of mainly low-risk, organ-confined PCs in the screening arm. Conclusions There was no

  4. 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.

  5. pSa causes oncogenic suppression of Agrobacterium by inhibiting VirE2 protein export.

    PubMed

    Lee, L Y; Gelvin, S B; Kado, C I

    1999-01-01

    When coresident with the Ti (tumor-inducing) plasmid, the 21-kDa product of the osa gene of the plasmid pSa can suppress crown gall tumorigenesis incited by Agrobacterium tumefaciens. Neither T-DNA processing nor vir (virulence) gene induction is affected by the presence of osa in the bacterium. We used Arabidopsis thaliana root segments and tobacco leaf discs to demonstrate that Osa inhibits A. tumefaciens from transforming these plants to the stable phenotypes of tumorigenesis, kanamycin resistance, and stable beta-glucuronidase (GUS) expression. When A. tumefaciens contained osa, the lack of expression of transient GUS activity in infected plant tissues, as well as the lack of systemic viral symptoms following agroinfection of Nicotiana benthamiana by tomato mottle virus, suggested that oncogenic suppression by Osa occurs before T-DNA enters the plant nucleus. The extracellular complementation of an A. tumefaciens virE2 mutant (the T-DNA donor strain) by an A. tumefaciens strain lacking T-DNA but containing a wild-type virE2 gene (the VirE2 donor strain) was blocked when osa was present in the VirE2 donor strain, but not when osa was present in the T-DNA donor strain. These data indicate that osa inhibits VirE2 protein, but not T-DNA export from A. tumefaciens. These data further suggest that VirE2 protein and T-DNA are separately exported from the bacterium. The successful infection of Datura stramonium plants and leaf discs of transgenic tobacco plants expressing VirE2 protein by an A. tumefaciens virE2 mutant carrying osa confirmed that oncogenic suppression by osa does not occur by blocking T-DNA transfer. Overexpression of virB9, virB10, and virB11 in A. tumefaciens did not overcome oncogenic suppression by osa. The finding that the expression of the osa gene by itself, rather than the formation of a conjugal intermediate with pSa, blocks transformation suggests that the mechanism of oncogenic suppression by osa may differ from that of the IncQ plasmid RSF

  6. Expanded organic building units for the construction of highly porous metal-organic frameworks.

    PubMed

    Kong, Guo-Qiang; Han, Zhi-Da; He, Yabing; Ou, Sha; Zhou, Wei; Yildirim, Taner; Krishna, Rajamani; Zou, Chao; Chen, Banglin; Wu, Chuan-De

    2013-10-25

    Two new organic building units that contain dicarboxylate sites for their self-assembly with paddlewheel [Cu2(CO2)4] units have been successfully developed to construct two isoreticular porous metal-organic frameworks (MOFs), ZJU-35 and ZJU-36, which have the same tbo topologies (Reticular Chemistry Structure Resource (RCSR) symbol) as HKUST-1. Because the organic linkers in ZJU-35 and ZJU-36 are systematically enlarged, the pores in these two new porous MOFs vary from 10.8 Å in HKUST-1 to 14.4 Å in ZJU-35 and 16.5 Å in ZJU-36, thus leading to their higher porosities with Brunauer-Emmett-Teller (BET) surface areas of 2899 and 4014 m(2) g(-1) for ZJU-35 and ZJU-36, respectively. High-pressure gas-sorption isotherms indicate that both ZJU-35 and ZJU-36 can take up large amounts of CH4 and CO2, and are among the few porous MOFs with the highest volumetric storage of CH4 under 60 bar and CO2 under 30 bar at room temperature. Their potential for high-pressure swing adsorption (PSA) hydrogen purification was also preliminarily examined and compared with several reported MOFs, thus indicating the potential of ZJU-35 and ZJU-36 for this important application. Studies show that most of the highly porous MOFs that can volumetrically take up the greatest amount of CH4 under 60 bar and CO2 under 30 bar at room temperature are those self-assembled from organic tetra- and hexacarboxylates that contain m-benzenedicarboxylate units with the [Cu2(CO2)4] units, because this series of MOFs can have balanced porosities, suitable pores, and framework densities to optimize their volumetric gas storage. The realization of the two new organic building units for their construction of highly porous MOFs through their self-assembly with [Cu2(CO2)4] units has provided great promise for the exploration of a large number of new tetra- and hexacarboxylate organic linkers based on these new organic building units in which different aromatic backbones can be readily incorporated

  7. 2008 Groundwater Monitoring Report Project Shoal Area, Corrective Action Unit 447

    SciTech Connect

    2009-03-01

    This report presents the 2008 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) at the Project Shoal Area (PSA) Subsurface Corrective Action Unit (CAU) 447 located in Churchill County, Nevada. Responsibility for the environmental site restoration of the PSA was transferred from the DOE Office of Environmental Management to LM on October 1, 2006. The environmental restoration process and corrective action strategy for CAU 447 are conducted in accordance with the Federal Facility Agreement and Consent Order (FFACO 1996, as amended February 2008) entered into by DOE, the U.S. Department of Defense, and the State of Nevada. The corrective action strategy for the site includes proof of concept monitoring in support of site closure. This report summarizes investigation activities associated with CAU 447 that were conducted at the site during 2008. This is the second groundwater monitoring report prepared by LM for the PSA

  8. 2009 Groundwater Monitoring Report Project Shoal Area, Corrective Action Unit 447

    SciTech Connect

    2010-03-01

    This report presents the 2009 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) at the Project Shoal Area (PSA) Subsurface Corrective Action Unit (CAU) 447 in Churchill County, Nevada. Responsibility for the environmental site restoration of the PSA was transferred from the DOE Office of Environmental Management to LM on October 1, 2006. The environmental restoration process and corrective action strategy for CAU 447 are conducted in accordance with the Federal Facility Agreement and Consent Order (FFACO 1996, as amended February 2008) entered into by DOE, the U.S. Department of Defense, and the State of Nevada. The corrective action strategy for the site includes monitoring in support of site closure. This report summarizes investigation activities associated with CAU 447 that were conducted at the PSA during fiscal year 2009.

  9. Light-regulated translation of chloroplast proteins. I. Transcripts of psaA-psaB, psbA, and rbcL are associated with polysomes in dark-grown and illuminated barley seedlings

    PubMed Central

    1988-01-01

    We have previously observed (Klein, R. R., and J. E. Mullet, 1986, J. Biol. Chem. 261:11138-11145) that translation of two 65-70-kD chlorophyll a-apoproteins of Photosystem I (gene products of psaA and psaB) and a 32-kD quinone-binding protein of Photosystem II (gene product of psbA) was not detected in plastids of dark-grown barley seedlings even though transcripts for these proteins were present. In the present study it was found that nearly all of the psaA-psaB transcripts in plastids of dark-grown plants were associated with membrane-bound polysomes. Membrane-associated polysomes from plastids of dark-grown plants synthesized the 65-70-kD chlorophyll a-apoproteins at low levels when added to a homologous in vitro translation extract capable of translation elongation. However, when etioplast membranes were disrupted with detergent, in vitro synthesis of the 65-70-kD chlorophyll a-apoproteins increased to levels observed with polysomes of plastids from illuminated plants. These results suggest that synthesis of the chlorophyll a-apoproteins of Photosystem I is arrested on membrane-bound polysomes at the level of polypeptide chain elongation. In addition to the selective activation of chlorophyll a- apoprotein translation, illumination also caused an increase in chloroplast polysomes (membrane-associated and stromal) and induced a recruitment of psbA and rbcL transcripts into chloroplast polysomes. These results indicate that in conjunction with the selective activation of chlorophyll a-apoprotein elongation, illumination also caused a general stimulation of chloroplast translation initiation. PMID:3339092

  10. 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

  11. Short-Cycle Adsorption Refrigerator

    NASA Technical Reports Server (NTRS)

    Chan, C. K.

    1988-01-01

    Modular adsorption/Joule-Thomson-effect refrigerator offers fast regeneration; adsorption/desorption cycle time expected to be 1 minute. Pressurized hydrogen generated by bank of compressor modules during heating phase passes through system of check valves and expands in Joule-Thomson junction as it enters refrigeration chamber. Hydrogen absorbs heat from load before it is sucked out by another bank of compressor modules in cooling phase.

  12. Adsorption properties of zeolites synthesized from coal fly ash for Cu (II).

    PubMed

    Song, Huiping; Cheng, Huaigang; Zhang, Zepeng; Cheng, Fangqin

    2014-09-01

    This study explored the hydrothermal synthesis of zeolites in a homogeneous reactor using coal fly ash (CFA) as a raw material via a two-step method at normal pressure. Fourier transform infrared spectroscopy and X-ray powder diffraction analysis showed that the synthetic products has the basic structural unit of microporous zeolite molecular sieves, and consiste of zeolite 4A and zeolite X. The ability of zeolites synthesized from CFAto adsorb Cu(ll) was studied. The optimal conditions for adsorption were as follows: pH 5 and dosage of modified CFA 4g l(-1). The isothermal adsorption of zeolites of Cu(ll) showed that the maximum adsorption quantity ranged from 69.44 (at 20 degrees C) to 140.85 mg g(-1) (at 50 degrees C). Adsorption kinetics analysis showed that chemical adsorption was the rate-controlling step. Apparent activation energy data, however, showed that the process of adsorption of Cu(II) had the features of physical adsorption. Thus, the adsorption process included both chemical and physical adsorption.

  13. Surfactant adsorption kinetics in microfluidics

    PubMed Central

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

    2016-01-01

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

  14. PDMS compound adsorption in context.

    PubMed

    Li, Nianzhen; Schwartz, Michael; Ionescu-Zanetti, Cristian

    2009-02-01

    Soft lithography of polydimethylsiloxane (PDMS), an elastomeric polymer, has enabled rapid and inexpensive fabrication of microfluidic devices for various biotechnology applications. However, concerns remain about adsorption of compounds on PDMS surfaces because of its porosity and hydrophobicity. Here, the adsorption of 2 small fluorescent dyes of different hydrophobicity (calcein and 5- (and 6-)carboxytetramethylrhodamine (TMR)) on PDMS surface has been systematically characterized, and PDMS adsorption has been compared with 2 traditional substrates: glass and polystyrene. To characterize adsorption in a regimen that is more relevant to microfluidic applications, the adsorption and desorption of the 2 compounds in PDMS microfluidic channels under flow conditions were also studied. Results showed that there was minimal adsorption of the hydrophilic compound calcein on PDMS, whereas the more hydrophobic TMR adsorbed on PDMS up to 4 times of that on glass or polystyrene. Under flow conditions, the desorption profiles and times needed to drop desorbed compound concentrations to negligible levels (desorption time constant, 10-42 s) were characterized. In the worst case scenario, after a 4-min exposure to TMR, 4 min of continuous wash resulted in compound concentrations in the microchannels to drop to values below 2 x 10(- 5) of the initial concentration.

  15. Potential roles of NCAM/PSA-NCAM proteins in depression and the mechanism of action of antidepressant drugs.

    PubMed

    Wędzony, Krzysztof; Chocyk, Agnieszka; Maćkowiak, Marzena

    2013-01-01

    Recently, it has been proposed that abnormalities in neuronal structural plasticity may underlie the pathogenesis of major depression, resulting in changes in the volume of specific brain regions, including the hippocampus (HIP), the prefrontal cortex (PC), and the amygdala (AMY), as well as the morphology of individual neurons in these brain regions. In the present survey, we compile the data regarding the involvement of the neural cell adhesion molecule (NCAM) protein and its polysialylated form (PSA-NCAM) in the pathogenesis of depression and the mechanism of action of antidepressant drugs (ADDs). Elevated expression of PSA-NCAM may reflect neuroplastic changes, whereas decreased expression implies a rigidification of neuronal morphology and an impedance of dynamic changes in synaptic structure. Special emphasis is placed on the clinical data, genetic models, and the effects of ADDs on NCAM/PSA-NCAM expression in the brain regions in which these proteins are constitutively expressed and neurogenesis is not a major factor; this emphasis is necessary to prevent cell proliferation and neurogenesis from obscuring the issue of brain plasticity. PMID:24552994

  16. The physical environment as a key factor in assessing the eutrophication status and vulnerability of shallow seas: PSA and EUTRISK

    NASA Astrophysics Data System (ADS)

    Druon, J.-N.; Schrimpf, W.; Dobricic, S.; Stips, A.; Vogt, P.

    2003-04-01

    Two spatial eutrophication indices of shallow marine ecosystems are proposed using hydrodynamic modelling and satellite remote sensing of ocean colour. The indices are derived in European Seas characterized by different physical regimes. The Physically Sensitive Area index (PSA) integrates the various supporting factors of eutrophication, i.e. the physical conditions that influences the upper layer primary production and the oxygen availability near the bottom. The PSA index portrays the location of oxygen deficiencies if both the nutrient distribution and the primary production would be uniformly distributed. The EUTrophication RISK index (EUTRISK) represents the spatial distribution of potential hypoxia for a given month integrating the physical supporting factors and the flux of organic matter estimated from satellite-derived chlorophyll-a maps, with an oxygen budget estimated on a monthly basis. The indices identify three main types of eutrophied waters: 1) eutrophic and sensitive, 2) eutrophic and resistant and 3) mesotrophic and sensitive. PSA and EUTRISK should provide assistance to policy makers to improve the ecological management of coastal marine waters and the scientific community to identify the impacted areas and the main mechanisms involved.

  17. Polymorphisms at the Microseminoprotein-beta (MSMB) Locus Associated With Physiological Variation in Beta-Microseminoprotein (β-MSP) and Prostate Specific Antigen (PSA) Levels

    PubMed Central

    Xu, Xing; Valtonen-André, Camilla; Sävblom, Charlotta; Halldén, Christer; Lilja, Hans; Klein, Robert J.

    2010-01-01

    Background rs10993994, a single nucleotide polymorphism (SNP) at the genetic locus encoding ß-microseminoprotein (β-MSP), is associated with both prostate cancer risk and levels of blood prostate-specific antigen (PSA), a biomarker used in prostate cancer screening. Therefore, we wished to determine the association between SNPs at MSMB, the gene encoding β-MSP, and levels of the prostate-produced biomarkers β-MSP, PSA, and human kallikrein 2 (hK2) in blood and semen. Methods Blood and semen from 304 healthy young Swedish men (aged 18-21) were assayed for β-MSP, PSA and hK2. SNPs around MSMB were genotyped from matched DNA and analyzed for quantitative association with biomarker levels. Empirical p-values were multiple test corrected and independence of each SNP’s effect was determined. Results rs10993994 is significantly associated with blood and semen levels of β-MSP (both p<1.0×10−7) and PSA (p=0.00014 and p=0.0019), and semen levels of hK2 (p=0.00027). Additional copies of the prostate cancer risk allele resulted in lower β-MSP but higher PSA levels, and singly explained 23% and 5% of the variation seen in semen β-MSP and PSA. Additional SNPs at MSMB are associated with β-MSP and PSA independently of rs10993994. Conclusions SNPs at MSMB correlate with physiological variation in β-MSP and PSA levels in the blood and semen of healthy young Swedish men. In particular, rs10993994 has a strong effect on β-MSP levels. Impact Our results suggest a mechanism by which rs10993994 may predispose to prostate cancer and raise the possibility that genetic variation may need to be considered in interpreting levels of these biomarkers. PMID:20696662

  18. TARP vaccination is associated with slowing in PSA velocity and decreasing tumor growth rates in patients with Stage D0 prostate cancer.

    PubMed

    Wood, Lauren V; Fojo, Antonio; Roberson, Brenda D; Hughes, Meghan S B; Dahut, William; Gulley, James L; Madan, Ravi A; Arlen, Philip M; Sabatino, Marianna; Stroncek, David F; Castiello, Luciano; Trepel, Jane B; Lee, Min-Jung; Parnes, Howard L; Steinberg, Seth M; Terabe, Masaki; Wilkerson, Julia; Pastan, Ira; Berzofsky, Jay A

    2016-08-01

    T-cell receptor alternate reading frame protein (TARP) is a 58-residue protein over-expressed in prostate and breast cancer. We investigated TARP peptide vaccination's impact on the rise in PSA (expressed as Slope Log(PSA) or PSA Doubling Time (PSADT)), validated tumor growth measures, and tumor growth rate in men with Stage D0 prostate cancer. HLA-A*0201 positive men were randomized to receive epitope-enhanced (29-37-9V) and wild-type (27-35) TARP peptides administered as a Montanide/GM-CSF peptide emulsion or as an autologous peptide-pulsed dendritic cell vaccine every 3 weeks for a total of five vaccinations with an optional 6th dose of vaccine at 36 weeks based on immune response or PSADT criteria with a booster dose of vaccine for all patients at 48 and 96 weeks. 41 patients enrolled with median on-study duration of 75 weeks at the time of this analysis. Seventy-two percent of patients reaching 24 weeks and 74% reaching 48 weeks had a decreased Slope Log(PSA) compared to their pre-vaccination baseline (p = 0.0012 and p = 0.0004 for comparison of overall changes in Slope Log(PSA), respectively). TARP vaccination also resulted in a 50% decrease in median tumor growth rate (g): pre-vaccine g = 0.0042/day, post-vaccine g = 0.0021/day (p = 0.003). 80% of subjects exhibited new vaccine-induced TARP-specific IFNγ ELISPOT responses but they did not correlate with decreases in Slope Log(PSA). Thus, vaccination with TARP peptides resulted in significant slowing in PSA velocity and reduction in tumor growth rate in a majority of patients with PSA biochemical recurrence. PMID:27622067

  19. PSA Response to Neoadjuvant Androgen Deprivation Therapy Is a Strong Independent Predictor of Survival in High-Risk Prostate Cancer in the Dose-Escalated Radiation Therapy Era

    SciTech Connect

    McGuire, Sean E.; Lee, Andrew K.; Cerne, Jasmina Z.; Munsell, Mark F.; Levy, Lawrence B.; Kudchadker, Rajat J.; Choi, Seungtaek L.; Nguyen, Quynh N.; Hoffman, Karen E.; Pugh, Thomas J.; Frank, Steven J.; Corn, Paul G.; Logothetis, Christopher J.; Kuban, Deborah A.

    2013-01-01

    Purpose: The aim of the study was to evaluate the prognostic value of prostate-specific antigen (PSA) response to neoadjuvant androgen deprivation therapy (ADT) prior to dose-escalated radiation therapy (RT) and long-term ADT in high-risk prostate cancer. Methods and Materials: We reviewed the charts of all patients diagnosed with high-risk prostate cancer and treated with a combination of long-term ADT (median, 24 months) and dose-escalated (median, 75.6 Gy) RT between 1990 and 2007. The associations among patient, tumor, and treatment characteristics with biochemical response to neoadjuvant ADT and their effects on failure-free survival (FFS), time to distant metastasis (TDM), prostate cancer-specific mortality (PCSM) and overall survival (OS) were examined. Results: A total of 196 patients met criteria for inclusion. Median follow-up time for patients alive at last contact was 7.0 years (range, 0.5-18.1 years). Multivariate analysis identified the pre-RT PSA concentration (<0.5 vs {>=}0.5 ng/mL) as a significant independent predictor of FFS (P=.021), TDM (P=.009), PCSM (P=.039), and OS (P=.037). On multivariate analysis, pretreatment PSA (iPSA) and African-American race were significantly associated with failure to achieve a pre-RT PSA of <0.5 ng/mL. Conclusions: For high-risk prostate cancer patients treated with long-term ADT and dose-escalated RT, a pre-RT PSA level {>=}0.5 ng/mL after neoadjuvant ADT predicts for worse survival measures. Both elevated iPSA and African-American race are associated with increased risk of having a pre-RT PSA level {>=}0.5 ng/mL. These patients should be considered for clinical trials that test newer, more potent androgen-depleting therapies such as abiraterone and MDV3100 in combination with radiation.

  20. A novel multiplex assay combining autoantibodies plus PSA has potential implications for classification of prostate cancer from non-malignant cases

    PubMed Central

    2011-01-01

    Background The lack of sufficient specificity and sensitivity among conventional cancer biomarkers, such as prostate specific antigen (PSA) for prostate cancer has been widely recognized after several decades of clinical implications. Autoantibodies (autoAb) among others are being extensively investigated as potential substitute markers, but remain elusive. One major obstacle is the lack of a sensitive and multiplex approach for quantifying autoAb against a large panel of clinically relevant tumor-associated antigens (TAA). Methods To circumvent preparation of phage lysates and purification of recombinant proteins, we identified B cell epitopes from a number of previously defined prostate cancer-associated antigens (PCAA). Peptide epitopes from cancer/testis antigen NY-ESO-1, XAGE-1b, SSX-2,4, as well as prostate cancer overexpressed antigen AMACR, p90 autoantigen, and LEDGF were then conjugated with seroMAP microspheres to allow multiplex measurement of autoAb present in serum samples. Moreover, simultaneous quantification of autoAb plus total PSA was achieved in one reaction, and termed the "A+PSA" assay. Results Peptide epitopes from the above 6 PCAA were identified and confirmed that autoAb against these peptide epitopes reacted specifically with the full-length protein. A pilot study was conducted with the A+PSA assay using pre-surgery sera from 131 biopsy-confirmed prostate cancer patients and 121 benign prostatic hyperplasia and/or prostatitis patients. A logistic regression-based A+PSA index was found to enhance sensitivities and specificities over PSA alone in distinguishing prostate cancer from nonmalignant cases. The A+PSA index also reduced false positive rate and improved the area under a receiver operating characteristic curve. Conclusions The A+PSA assay represents a novel platform that integrates autoAb signatures with a conventional cancer biomarker, which may aid in the diagnosis and prognosis of prostate cancer and others. PMID:21504557

  1. Adsorption and Desorption of Nitrogen and Water Vapor by clay

    NASA Astrophysics Data System (ADS)

    Cui, Deshan; Chen, Qiong; Xiang, Wei; Huang, Wei

    2015-04-01

    Adsorption and desorption of nitrogen and water vapor by clay has a significant impact on unsaturated soil physical and mechanical properties. In order to study the adsorption and desorption characteristics of nitrogen and water vapor by montmorillonite, kaolin and sliding zone soils, the Autosorb-iQ specific surface area and pore size analyzer instrument of United State was taken to carry out the analysis test. The adsorption and desorption of nitrogen at 77K and water vapor at 293K on clay sample were conducted. The theories of BET, FHH and hydration energy were taken to calculate the specific surface, surface fractal dimension and adsorption energy. The results show that the calculated specific surface of water vapor by clay is bigger than nitrogen adsorption test because clay can adsorb more water vapor molecule than nitrogen. Smaller and polar water vapor molecule can access the micropore and then adsorb on the mineral surface and mineral intralayer, which make the mineral surface cations hydrate and the mineral surface smoother. Bigger and nonpolar nitrogen molecule can not enter into the micropore as water vapor molecule and has weak interaction with clay surface.

  2. C-reactive protein haplotype is associated with high PSA as a marker of metastatic prostate cancer but not with overall cancer risk

    PubMed Central

    Eklund, C M; Tammela, T L J; Schleutker, J; Hurme, M

    2009-01-01

    Growing evidence points to a role for inflammation in prostate carcinogenesis. The significance of C-reactive protein (CRP), an inflammatory and innate immunity molecule, has not been evaluated thoroughly in prostate cancer (PC). In this study of 739 Finnish patients with PC and 760 healthy men, we evaluated the associations of CRP genotypes and haplotypes with total PC risk and PC progression, using prostate-specific antigen (PSA) as a marker of metastatic disease. Although the haplotype frequencies were similar in patients and controls, an association between haplotype ACCCA and patients' PSA levels was found. The carriers more often had a high PSA than non-carriers (P=0.0002) and the SNP rs2794521 A-allele and rs1800947 C-allele carriers had a higher PSA than non-carriers (P=0.009 and P=0.0004, respectively). A trend for a younger age at diagnosis was found among the carriers of ACCCA (P=0.07) and the rs1800947 C-allele (P=0.06), as well as a trend for the latter to have more likely metastases (P=0.06), but not after Bonferroni correction (α=0.00208). This is the first study to suggest association between PSA and CRP variants in PC and, therefore, further studies are warranted. CRP alleles previously found to protect against increased CRP levels are now suggested to be associated with metastatic PC, indicated by elevated PSA. PMID:19436291

  3. PSA-NCAM in the posterodorsal medial amygdala is necessary for the pubertal emergence of attraction to female odors in male hamsters.

    PubMed

    Job, Martin O; Cooke, Bradley M

    2015-09-01

    During puberty, attention turns away from same-sex socialization to focus on the opposite sex. How the brain mediates this change in perception and motivation is unknown. Polysialylated neural cell adhesion molecule (PSA-NCAM) virtually disappears from most of the central nervous system after embryogenesis, but it remains elevated in discrete regions of the adult brain. One such brain area is the posterodorsal subnucleus of the medial amygdala (MePD). The MePD has been implicated in male sexual attraction, measured here as the preference to investigate female odors. We hypothesize that PSA-NCAM gates hormone-dependent plasticity necessary for the emergence of males' attraction to females. To evaluate this idea, we first measured PSA-NCAM levels across puberty in several brain regions, and identified when female odor preference normally emerges in male Syrian hamsters. We found that MePD PSA-NCAM staining peaks shortly before the surge of pubertal androgen and the emergence of preference. To test the necessity of PSA-NCAM for female odor preference, we infused endo-neuraminidase-N into the MePD to deplete it of PSAs before female odor preference normally appears. This blocked female odor preference, which suggests that PSA-NCAM facilitates behaviorally relevant, hormone-driven plasticity. PMID:26335887

  4. PSA-NCAM-negative neural crest cells emerging during neural induction of pluripotent stem cells cause mesodermal tumors and unwanted grafts.

    PubMed

    Lee, Dongjin R; Yoo, Jeong-Eun; Lee, Jae Souk; Park, Sanghyun; Lee, Junwon; Park, Chul-Yong; Ji, Eunhyun; Kim, Han-Soo; Hwang, Dong-Youn; Kim, Dae-Sung; Kim, Dong-Wook

    2015-05-12

    Tumorigenic potential of human pluripotent stem cells (hPSCs) is an important issue in clinical applications. Despite many efforts, PSC-derived neural precursor cells (NPCs) have repeatedly induced tumors in animal models even though pluripotent cells were not detected. We found that polysialic acid-neural cell adhesion molecule (PSA-NCAM)(-) cells among the early NPCs caused tumors, whereas PSA-NCAM(+) cells were nontumorigenic. Molecular profiling, global gene analysis, and multilineage differentiation of PSA-NCAM(-) cells confirm that they are multipotent neural crest stem cells (NCSCs) that could differentiate into both ectodermal and mesodermal lineages. Transplantation of PSA-NCAM(-) cells in a gradient manner mixed with PSA-NCAM(+) cells proportionally increased mesodermal tumor formation and unwanted grafts such as PERIPHERIN(+) cells or pigmented cells in the rat brain. Therefore, we suggest that NCSCs are a critical target for tumor prevention in hPSC-derived NPCs, and removal of PSA-NCAM(-) cells eliminates the tumorigenic potential originating from NCSCs after transplantation. PMID:25937368

  5. Mucosal immunization with PsaA protein, using chitosan as a delivery system, increases protection against acute otitis media and invasive infection by Streptococcus pneumoniae.

    PubMed

    Xu, J-H; Dai, W-J; Chen, B; Fan, X-Y

    2015-03-01

    As infection with Streptococcus pneumoniae (mainly via the mucosal route) is a leading cause of acute otitis media, sinus and bacterial pneumonia, the mucosal immunity plays an important role in the prevention of pneumococcal diseases. Therefore, intranasal vaccination may be an effective immunization strategy, but requires appropriate mucosal vaccine delivery systems. In this work, chitosan was used as a mucosal delivery system to form chitosan-PsaA nanoparticles based on ionotropic gelation methods and used to immunize BALB/c mice intranasally. Compared to mice immunized with naked PsaA, levels of IFN-γ, IL-17A and IL-4 in spleen lymphocytes, the systemic (IgG in serum) and mucosal (IgA in mucosal lavage) specific antibodies were enhanced significantly in mice inoculated with chitosan-PsaA. Furthermore, increased protection against acute otitis media following middle ear challenge with pneumococcus serotype 14, and improved survival following intraperitoneal challenge with pneumococcus serotype 3 or serotype 14, was found in the mice immunized with chitosan-PsaA nanoparticles. Thus, intranasal immunization with chitosan-PsaA can successfully induce mucosal and systemic immune responses and increase protection against pneumococcal acute otitis media and invasive infections. Hence, intranasal immunization with PsaA protein, based on chitosan as a delivery system, is an efficient immunization strategy for preventing pneumococcal infections.

  6. PSA velocity does not aid the detection of prostate cancer in men with a prior negative biopsy: data from the European Randomized Study of Prostate Cancer Screening in Göteborg, Sweden and Rotterdam, Netherlands

    PubMed Central

    Vickers, Andrew J.; Wolters, Tineke; Savage, Caroline J.; Cronin, Angel M.; O’Brien, M. Frank; Roobol, Monique J.; Aus, Gunnar; Scardino, Peter T.; Hugosson, Jonas; Schröder, Fritz H.; Lilja, Hans

    2012-01-01

    Purpose Prostate specific antigen (PSA) velocity has been proposed as a marker to aid detection of prostate cancer. We sought to determine whether PSA velocity could predict the results of repeat biopsy in men with persistently elevated PSA after initial negative biopsy. Materials and Methods We identified 1,837 men who participated in the Göteborg or Rotterdam section of the European Randomized Screening study of Prostate Cancer (ERSPC), and who had one or more subsequent prostate biopsies after an initial negative finding. We evaluated whether PSA velocity improved predictive accuracy beyond that of PSA alone. Results There were a total of 2579 repeat biopsies, of which 363 (14%) were positive for prostate cancer, and 44 (1.7%) were high grade (Gleason score ≥7). Although PSA velocity was statistically associated with cancer risk (p<0.001), it had very low predictive accuracy (area-under-the-curve [AUC] of 0.55). There was some evidence that PSA velocity improved AUC compared to PSA for high grade cancer. However, the small increase in risk associated with high PSA velocity – from 1.7 % to 2.8% as velocity increased from 0 to 1 ng / ml / year - is of questionable clinical relevance. Conclusions Men with a prior negative biopsy have a lower risk for prostate cancer at subsequent biopsies, with high grade disease particularly rare. We found little evidence to support the use of PSA velocity to aid decisions about repeat biopsy for prostate cancer. PMID:20643434

  7. Characteristics of PAHs adsorption on inorganic particles and activated sludge in domestic wastewater treatment.

    PubMed

    Liu, J J; Wang, X C; Fan, B

    2011-05-01

    The occurrence of polycyclic aromatic hydrocarbons (PAHs) in a domestic wastewater treatment plant (WWTP) was investigated in a 1 year period. In order to understand how PAHs were removed at different stages of the treatment process, adsorption experiments were conducted using quartz sand, kaolinite, and natural clay as inorganic adsorbents and activated sludge as organic adsorbent for adsorbing naphthalene, phenanthrene, and pyrene. As a result, the adsorption of PAHs by the inorganic adsorbents well followed the Langmuir isotherm while that by the activated sludge well followed the Freundlich isotherm. By bridging equilibrium partitioning coefficient with the parameters of adsorption isotherm, a set of mathematical models were developed. Under an assumption that in the primary settler PAHs removal was by adsorption onto inorganic particles and in the biological treatment unit it was by adsorption onto activated sludge, the model calculation results fairly reflected the practical condition in the WWTP.

  8. Multimodal underwater adsorption of oxide nanoparticles on catechol-based polymer nanosheets

    NASA Astrophysics Data System (ADS)

    Yamamoto, Shunsuke; Uchiyama, Shun; Miyashita, Tokuji; Mitsuishi, Masaya

    2016-03-01

    Multimodal underwater adsorption behaviour of catechol units was demonstrated by examining the adsorption of different oxide nanoparticles on nanoscale-integrated polymer nanosheets. Catechol-based polymer nanosheets were fabricated using the Langmuir-Blodgett (LB) technique with random copolymers (p(DDA/DMA)s) of N-dodecylacrylamide (DDA) and dopamine methacrylamide (DMA). The p(DDA/DMA) nanosheets were immersed into water dispersions of SiO2, Al2O3, and WO3 nanoparticles (NPs) respectively. The results show that the adsorption properties can be altered by varying the NP type: SiO2 NP adsorption was observed only below pH = 6, at which the o-quinone form in p(DDA/DMA) nanosheets transforms into the catechol form or vice versa. However, their transition point for Al2O3 NP adsorption was found at approximately pH 10, at which the surface potential of Al2O3 NPs changes the charge polarity, indicating that the electrostatic interaction is predominant. For WO3 NPs, adsorption was observed when citric acid, which modifies the surface of WO3 NPs by complex formation, was used as a pH-controlling agent, but no adsorption was found for hydrochloric acid used as a pH controlling agent. FT-IR measurements proved that miniscule amounts of water molecules were trapped in p(DDA/DMA) nanosheets and that they acquired hydrogen bonding network formations, which might assist nanoparticle adsorption underwater and make the catechol units adjustable. The results indicate that the nanoscale spatial arrangements of catechol units in films are crucially important for the application of multimodal adsorption of oxide nanoparticles on catechol-based polymer materials.Multimodal underwater adsorption behaviour of catechol units was demonstrated by examining the adsorption of different oxide nanoparticles on nanoscale-integrated polymer nanosheets. Catechol-based polymer nanosheets were fabricated using the Langmuir-Blodgett (LB) technique with random copolymers (p(DDA/DMA)s) of N

  9. Undetectable ultrasensitive PSA after radical prostatectomy for prostate cancer predicts relapse-free survival.

    PubMed

    Doherty, A P; Bower, M; Smith, G L; Miano, R; Mannion, E M; Mitchell, H; Christmas, T J

    2000-12-01

    Radical retropubic prostatectomy is considered by many centres to be the treatment of choice for men aged less than 70 years with localized prostate cancer. A rise in serum prostate-specific antigen after radical prostatectomy occurs in 10-40% of cases. This study evaluates the usefulness of novel ultrasensitive PSA assays in the early detection of biochemical relapse. 200 patients of mean age 61. 2 years underwent radical retropubic prostatectomy. Levels < or = 0.01 ng ml-1 were considered undetectable. Mean pre-operative prostate-specific antigen was 13.3 ng ml-1. Biochemical relapse was defined as 3 consecutive rises. The 2-year biochemical disease-free survival for the 134 patients with evaluable prostate-specific antigen nadir data was 61.1% (95% CI: 51.6-70.6%). Only 2 patients with an undetectable prostate-specific antigen after radical retropubic prostatectomy biochemically relapsed (3%), compared to 47 relapses out of 61 patients (75%) who did not reach this level. Cox multivariate analysis confirms prostate-specific antigen nadir < or = 0.01 ng ml-1 to be a superb independent variable predicting a favourable biochemical disease-free survival (P < 0.0001). Early diagnosis of biochemical relapse is feasible with sensitive prostate-specific antigen assays. These assays more accurately measure the prostate-specific antigen nadir, which is an excellent predictor of biochemical disease-free survival. Thus, sensitive prostate-specific antigen assays offer accurate prognostic information and expedite decision-making regarding the use of salvage prostate-bed radiotherapy or hormone therapy.

  10. The effect of testosterone replacement therapy on prostate-specific antigen (PSA) levels in men being treated for hypogonadism: a systematic review and meta-analysis.

    PubMed

    Kang, De-Ying; Li, Hong-Jun

    2015-01-01

    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 is minimal

  11. Risk of Pathologic Upgrading or Locally Advanced Disease in Early Prostate Cancer Patients Based on Biopsy Gleason Score and PSA: A Population-Based Study of Modern Patients

    SciTech Connect

    Caster, Joseph M.; Falchook, Aaron D.; Hendrix, Laura H.; Chen, Ronald C.

    2015-06-01

    Purpose: Radiation oncologists rely on available clinical information (biopsy Gleason score and prostate-specific antigen [PSA]) to determine the optimal treatment regimen for each prostate cancer patient. Existing published nomograms correlating clinical to pathologic extent of disease were based on patients treated in the 1980s and 1990s at select academic institutions. We used the Surveillance, Epidemiology, and End Results (SEER) database to examine pathologic outcomes (Gleason score and cancer stage) in early prostate cancer patients based on biopsy Gleason score and PSA concentration. Methods and Materials: This analysis included 25,858 patients whose cancer was diagnosed between 2010 and 2011, with biopsy Gleason scores of 6 to 7 and clinical stage T1 to T2 disease, who underwent radical prostatectomy. In subgroups based on biopsy Gleason score and PSA level, we report the proportion of patients with pathologically advanced disease (positive surgical margin or pT3-T4 disease) or whose Gleason score was upgraded. Logistic regression was used to examine factors associated with pathologic outcomes. Results: For patients with biopsy Gleason score 6 cancers, 84% of those with PSA <10 ng/mL had surgical T2 disease with negative margins; this decreased to 61% in patients with PSA of 20 to 29.9 ng/mL. Gleason score upgrading was seen in 43% (PSA: <10 ng/mL) to 61% (PSA: 20-29.9 ng/mL) of biopsy Gleason 6 patients. Patients with biopsy Gleason 7 cancers had a one-third (Gleason 3 + 4; PSA: <10 ng/mL) to two-thirds (Gleason 4 + 3; PSA: 20-29.9 ng/mL) probability of having pathologically advanced disease. Gleason score upgrading was seen in 11% to 19% of patients with biopsy Gleason 4 + 3 cancers. Multivariable analysis showed that higher PSA and older age were associated with Gleason score upgrading and pathologically advanced disease. Conclusions: This is the first population-based study to examine pathologic extent of disease and pathologic Gleason score

  12. Prognostic Significance of 5-Year PSA Value for Predicting Prostate Cancer Recurrence After Brachytherapy Alone and Combined With Hormonal Therapy and/or External Beam Radiotherapy

    SciTech Connect

    Stock, Richard G. Klein, Thomas J.; Cesaretti, Jamie A.; Stone, Nelson N.

    2009-07-01

    Purpose: To analyze the prognosis and outcomes of patients who remain free of biochemical failure during the first 5 years after treatment. Methods and Materials: Between 1991 and 2002, 742 patients with prostate cancer were treated with brachytherapy alone (n = 306), brachytherapy and hormonal therapy (n = 212), or combined implantation and external beam radiotherapy (with or without hormonal therapy; n = 224). These patients were free of biochemical failure (American Society for Therapeutic Radiology and Oncology [ASTRO] definition) during the first 5 post-treatment years and had a documented 5-year prostate-specific antigen (PSA) value. The median follow-up was 6.93 years. Results: The actuarial 10-year freedom from PSA failure rate was 97% using the ASTRO definition and 95% using the Phoenix definition. The median 5-year PSA level was 0.03 ng/mL (range, 0-3.6). The 5-year PSA value was {<=}0.01 in 47.7%, >0.01-0.10 in 31.1%, >0.10-0.2 in 10.2%, >0.2-0.5 in 7.82%, and >0.5 in 3.10%. The 5-year PSA value had prognostic significance, with a PSA value of {<=}0.2 ng/mL (n = 661) corresponding to a 10-year freedom from PSA failure rate of 99% with the ASTRO definition and 98% with the Phoenix definition vs. 86% (ASTRO definition) and 81% (Phoenix definition) for a PSA value {>=}0.2 ng/mL (n = 81; p < .0001). The treatment regimen had no effect on biochemical failure. None of the 742 patients in this study developed metastatic disease or died of prostate cancer. Conclusion: The results of this study have shown that the prognosis for patients treated with brachytherapy and who remain biochemically free of disease for {>=}5 years is excellent and none developed metastatic disease during the first 10 years after treatment. The 5-year PSA value is prognostic, and patients with a PSA value <0.2 ng/mL are unlikely to develop subsequent biochemical relapse.

  13. Metal adsorption on mosses: Toward a universal adsorption model.

    PubMed

    González, A G; Pokrovsky, O S

    2014-02-01

    This study quantifies the adsorption of heavy metals on 4 typical moss species used for environmental monitoring in the moss bag technique. The adsorption of Cu(2+), Cd(2+), Ni(2+), Pb(2+) and Zn(2+) onto Hypnum sp., Sphagnum sp., Pseudoscleropodium purum and Brachytecium rutabulum has been investigated using a batch reactor in a wide range of pH (1.3-11.0) and metal concentrations in solution (1.6μM-3.8mM). A Linear Programming Model (LPM) was applied for the experimental data to derive equilibrium constants and the number of surface binding sites. The surface acid-base titration performed for 4 mosses at a pH range of 3-10 in 0.1M NaNO3 demonstrated that Sphagnum sp. is the most efficient adsorbent as it has the maximal number of proton-binding sites on the surface (0.65mmol g(-1)). The pKa computed for all the moss species suggested the presence of 5 major functional groups: phosphodiester, carboxyl, phosphoryl, amine and polyphenols. The results of pH-edge experiments demonstrated that B. rutabulum exhibits the highest percentage of metal adsorption and has the highest number of available sites for most of the metals studied. However, according to the results of the constant pH "Langmuirian" isotherm, Sphagnum sp. can be considered as the strongest adsorbent, although the relative difference from other mosses is within 20%. The LPM was found to satisfactorily fit the experimental data in the full range of the studied solution parameters. The results of this study demonstrate a rather similar pattern of five metal adsorptions on mosses, both as a function of pH and as a metal concentration, which is further corroborated by similar values of adsorption constants. Therefore, despite the species and geographic differences between the mosses, a universal adsorption edge and constant pH adsorption isotherm can be recommended for 4 studied mosses. The quantitative comparison of metal adsorption with other common natural organic and inorganic materials demonstrates

  14. Fractional Statistical Theory of Adsorption of Polyatomics

    NASA Astrophysics Data System (ADS)

    Riccardo, J. L.; Ramirez-Pastor, A. J.; Romá, F.

    2004-10-01

    A new theoretical description of fractional statistical theory of adsorption (FSTA) phenomena is presented based on Haldane’s statistics. Thermodynamic functions for adsorption of polyatomics are analytically developed. The entropy is characterized by an exclusion parameter g, which relates to the configuration of the admolecules and surface geometry. FSTA provides a simple framework to address a large class of complex adsorption systems. Comparisons of theoretical adsorption isotherms with experiments and simulations indicate that adsorption configuration and adsorption energy can accurately be assessed from this theory.

  15. Fractional statistical theory of adsorption of polyatomics.

    PubMed

    Riccardo, J L; Ramirez-Pastor, A J; Romá, F

    2004-10-29

    A new theoretical description of fractional statistical theory of adsorption (FSTA) phenomena is presented based on Haldane's statistics. Thermodynamic functions for adsorption of polyatomics are analytically developed. The entropy is characterized by an exclusion parameter g, which relates to the configuration of the admolecules and surface geometry. FSTA provides a simple framework to address a large class of complex adsorption systems. Comparisons of theoretical adsorption isotherms with experiments and simulations indicate that adsorption configuration and adsorption energy can accurately be assessed from this theory. PMID:15525184

  16. Selective electrochemical detection of 2,4,6-trinitrotoluene (TNT) in water based on poly(styrene-co-acrylic acid) PSA/SiO2/Fe3O4/AuNPs/lignin-modified glassy carbon electrode.

    PubMed

    Mahmoud, Khaled A; Abdel-Wahab, Ahmed; Zourob, Mohammed

    2015-01-01

    A new versatile electrochemical sensor based on poly(styrene-co-acrylic acid) PSA/SiO2/Fe3O4/AuNPs/lignin (L-MMS) modified glassy carbon electrode (GCE) was developed for the selective detection of trace trinitrotoluene (TNT) from aqueous media with high sensitivity. The fabricated magnetic microspheres were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). L-MMS films were cast on the GCE surface to fabricate the TNT sensing electrode. The limit of detection (LOD) of TNT determined by the amperometric i-t curve reached 35 pM. The lignin film and well packed Fe3O4/AuNPs facilitated the pre-concentration of trace TNT on the electrode surface resulting in a fast amperometric response of 3 seconds near the detection limit. The high sensitivity and excellent catalytic activity of the modified electrode could be attributed to the lignin layer and highly packed Fe3O4/AuNPs on the electrode surface. The total recovery of TNT from tapwater and seawater matrices was 98% and 96%, respectively. The electrode film was highly stable after five repeated adsorption/desorption cycles. The new electrochemical sensing scheme provides a highly selective, sensitive and versatile assay for the in-situ detection of TNT in complex water media.

  17. Selective electrochemical detection of 2,4,6-trinitrotoluene (TNT) in water based on poly(styrene-co-acrylic acid) PSA/SiO2/Fe3O4/AuNPs/lignin-modified glassy carbon electrode.

    PubMed

    Mahmoud, Khaled A; Abdel-Wahab, Ahmed; Zourob, Mohammed

    2015-01-01

    A new versatile electrochemical sensor based on poly(styrene-co-acrylic acid) PSA/SiO2/Fe3O4/AuNPs/lignin (L-MMS) modified glassy carbon electrode (GCE) was developed for the selective detection of trace trinitrotoluene (TNT) from aqueous media with high sensitivity. The fabricated magnetic microspheres were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). L-MMS films were cast on the GCE surface to fabricate the TNT sensing electrode. The limit of detection (LOD) of TNT determined by the amperometric i-t curve reached 35 pM. The lignin film and well packed Fe3O4/AuNPs facilitated the pre-concentration of trace TNT on the electrode surface resulting in a fast amperometric response of 3 seconds near the detection limit. The high sensitivity and excellent catalytic activity of the modified electrode could be attributed to the lignin layer and highly packed Fe3O4/AuNPs on the electrode surface. The total recovery of TNT from tapwater and seawater matrices was 98% and 96%, respectively. The electrode film was highly stable after five repeated adsorption/desorption cycles. The new electrochemical sensing scheme provides a highly selective, sensitive and versatile assay for the in-situ detection of TNT in complex water media. PMID:26540539

  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. Adsorption-induced colloidal aggregation

    NASA Astrophysics Data System (ADS)

    Law, B. M.; Petit, J.-M.; Beysens, D.

    1998-03-01

    Reversible colloidal aggregation in binary liquid mixtures has been studied for a number of years. As the phase separation temperature of the liquid mixture is approached the thickness of an adsorption layer around the colloidal particles increases. Beysens and coworkers have demonstrated experimentally that this adsorption layer is intimately connected with the aggregation of the colloidal particles, however, no definitive theory has been available which can explain all of the experimental observations. In this contribution we describe an extension of the Derjaguin, Landau, Verwey, and Overbeek theory of colloidal aggregation which takes into account the presence of the adsorption layer and which more realistically models the attractive dispersion interactions. This modified theory can quantitatively account for many of the observed experimental features such as the characteristics of the aggregated state, the general shape of the aggregation line, and the temperature dependence of the second virial coefficient for a lutidine-water mixture containing a small volume fraction of silica colloidal particles.

  20. High-Risk Prostate Cancer With Gleason Score 8-10 and PSA Level {<=}15 ng/ mL Treated With Permanent Interstitial Brachytherapy

    SciTech Connect

    Fang, L. Christine; Merrick, Gregory S.; Butler, Wayne M.; Galbreath, Robert W.; Murray, Brian C.; Reed, Joshua L.; Adamovich, Edward; Wallner, Kent E.

    2011-11-15

    Purpose: With widespread prostate-specific antigen (PSA) screening, there has been an increase in men diagnosed with high-risk prostate cancer defined by a Gleason score (GS) {>=}8 coupled with a relatively low PSA level. The optimal management of these patients has not been defined. Cause-specific survival (CSS), biochemical progression-free survival (bPFS), and overall survival (OS) were evaluated in brachytherapy patients with a GS {>=}8 and a PSA level {<=}15 ng/mL with or without androgen-deprivation therapy (ADT). Methods and Materials: From April 1995 to October 2005, 174 patients with GS {>=}8 and a PSA level {<=}15 ng/mL underwent permanent interstitial brachytherapy. Of the patients, 159 (91%) received supplemental external beam radiation, and 113 (64.9%) received ADT. The median follow-up was 6.6 years. The median postimplant Day 0 minimum percentage of the dose covering 90% of the target volume was 121.1% of prescription dose. Biochemical control was defined as a PSA level {<=}0.40 ng/mL after nadir. Multiple parameters were evaluated for impact on survival. Results: Ten-year outcomes for patients without and with ADT were 95.2% and 92.5%, respectively, for CSS (p = 0.562); 86.5% and 92.6%, respectively, for bPFS (p = 0.204); and 75.2% and 66.0%, respectively, for OS (p = 0.179). The median post-treatment PSA level for biochemically controlled patients was <0.02 ng/mL. Multivariate analysis failed to identify any predictors for CSS, whereas bPFS and OS were most closely related to patient age. Conclusions: Patients with GS {>=}8 and PSA level {<=}15 ng/mL have excellent bPFS and CSS after brachytherapy with supplemental external beam radiotherapy. The use of ADT did not significantly impact bPFS, CSS, or OS.

  1. Detection of Local, Regional, and Distant Recurrence in Patients With PSA Relapse After External-Beam Radiotherapy Using {sup 11}C-Choline Positron Emission Tomography

    SciTech Connect

    Breeuwsma, Anthonius J.; Pruim, Jan; Bergh, Alphons C.M. van den; Leliveld, Anna M.; Nijman, Rien J.M.; Dierckx, Rudi A.J.O.; Jong, Igle J. de

    2010-05-01

    Purpose: An elevated serum prostate-specific antigen (PSA) level cannot distinguish between local-regional recurrences and the presence of distant metastases after treatment with curative intent for prostate cancer. With the advent of salvage treatment such as cryotherapy, it has become important to localize the site of recurrence (local or distant). In this study, the potential of {sup 11}C-choline positron emission tomography (PET) to identify site of recurrence was investigated in patients with rising PSA after external-beam radiotherapy (EBRT). Methods and Materials: Seventy patients with histologically proven prostate cancer treated with EBRT and showing biochemical recurrence as defined by American Society for Therapeutic Radiology and Oncology consensus statement and 10 patients without recurrence underwent a PET scan using 400 MBq {sup 11}C-choline intravenously. Biopsy-proven histology from the site of suspicion, findings with other imaging modalities, clinical follow-up and/or response to adjuvant therapy were used as comparative references. Results: None of the 10 patients without biochemical recurrence had a positive PET scan. Fifty-seven of 70 patients with biochemical recurrence (median PSA 9.1 ng/mL; mean PSA 12.3 ng/mL) showed an abnormal uptake pattern (sensitivity 81%). The site of recurrence was only local in 41 of 57 patients (mean PSA 11.1 ng/mL at scan), locoregionally and/or distant in 16 of 57 patients (mean PSA 17.7 ng/mL). Overall the positive predictive value and negative predictive value for {sup 11}C-choline PET scan were 1.0 and 0.44 respectively. Accuracy was 84%. Conclusions: {sup 11}C-choline PET scan is a sensitive technique to identify the site of recurrence in patients with PSA relapse after EBRT for prostate cancer.

  2. Luminescence energy transfer detection of PSA in red region based on Mn2+-enhanced NaYF4:Yb, Er upconversion nanorods.

    PubMed

    Zhang, Jianguo; Wang, Shaozhen; Gao, Ni; Feng, Dexiang; Wang, Lun; Chen, Hongqi

    2015-10-15

    A new turn-on luminescence energy transfer (LET) system has been designed for the detection of prostate specific antigen (PSA, a cancer marker) that utilizes Mn(2+)-enhanced long wavelength luminescence NaYF4:Yb, Er upconversion nanorods as the donor and gold nanorods as the acceptor. The Mn(2+)-doped NaYF4:Yb,Er upconversion luminescence nanorods with an emission peak located in the red region were synthesized. The presence of Mn(2+) markedly increased the luminescence intensity over that of the NaYF4:Yb, Er upconversion nanomaterials (excited by a 980 nm continuous wavelength laser). The surfaces of Mn(2+)-doped NaYF4:Yb, Er upconversion nanorods were modified with poly(acrylic acid). Antibodies against prostate specific antigen were bound to the surface of the carboxyl-functionalized upconversion nanorods, which acted as the energy donor in this LET system. Gold nanorods with an absorption band at ~666 nm were synthesized by the seed growth method, acted as the energy acceptor. The emission band of the upconversion nanorods overlapped well with the absorption band of the gold nanorods. The luminescence was quenched because of the electrostatic interactions that shortened the distance between the donor (negatively charged) and the accepter (positively charged).When the PSA antigen was added into the system, the energy acceptor and the energy donors were separated because the binding affinity between PSA and anti-PSA was greater than the electrostatic interactions, and thereby the luminescence was recovered. The linear range of detecting PSA was from 0.1172 to 18.75 ng/mL (R=0.995), with a limit of detection for PSA as low as 0.1129 ng/mL. The method was successfully applied to the sensing of PSA in human serum samples. PMID:25996781

  3. [Adsorption and partition of PAHS on particles of the Yellow River].

    PubMed

    Meng, Li-hong; Xia, Xing-hui; Yu, Hui; Sha, Yu-juan

    2006-05-01

    Experiments were carried out to study the sorption of PAHs Benzo(a)pyrene, chrysene and Benzo(g, h, i)perylene on particles of the Yellow River. The contributions of adsorption and partition to the sorption of PAHs were investigated. Several significant results were obtained from the study: (1) The total sorption capacity increases with the particle content while the sorption capacity of unit weight particle decreases; the isotherms of Benzo(a)pyrene depend on the particle content. (2) Isotherms of Benzo(a) pyrene can be fitted with the Dual Adsorption-Partition model under different particle content; the measured value of the adsorption and partition are in accord with the theoretical value of the Dual Adsorption-Partition model. (3) The adsorption is predominant in the sorption of Benzo(a)pyrene. When the particle contents are 3, 8 and 15 g/L and the liquid equilibrium concentrations are 2.84, 2.35 and 3.4 microg/L, respectively, the contributions of adsorption are 67.8%, 65.6% and 62.69%, respectively. In addition, the contributions of adsorption have a decreasing trend with the increase of the particle content. (4) The sorption capacity of Benzo (a) pyrene being alone are bigger than that with other PAHs chrysene and Benzo(g, h, i)perylene coexisting in the water system, this also proves that the adsorption is predominant in the sorption of PAHs.

  4. Adsorption on a stepped substrate

    NASA Astrophysics Data System (ADS)

    Merikoski, J.; Timonen, J.; Kaski, K.

    1994-09-01

    The effect of substrate steps on the adsorption of particles is considered. The problem is formulated as a lattice-gas model with nearest neighbor interactions and it is studied by a numerical transfer-matrix method. In particular, the influence of the substrate-induced row potential on adsorbed monolayers is discussed. It is found that strong row-transition-like features appear in the presence of a row potential and it is suggested that these may be seen in adsorption on vicinal faces.

  5. Fractional statistical theory of adsorption applied to protein adsorption.

    PubMed

    Quiroga, E; Centres, P M; Ochoa, N A; Ramirez-Pastor, A J

    2013-01-15

    Experimental adsorption isotherms of bovine serum albumin (BSA) adsorbed on sulfonated microspheres were described by means of two analytical models: the first is the well-known Langmuir-Freundlich model (LF), and the second, called fractional statistical theory of adsorption (FSTA), is a statistical thermodynamics model developed recently by Ramirez-Pastor et al. [Phys. Rev. Lett. 93 (2004) 186101]. The experimental data, obtained by Hu et al. [Biochem. Eng. J. 23 (2005) 259] for different concentrations of sulfonate group on the surface of the microspheres, were correlated by using a fitting algorithm based on least-squares statistics. The combination of LF and FSTA models, along with the choice of an adequate fitting procedure, allowed us to obtain several conclusions: (i) as previously reported in the literature, the maximum amount adsorbed increases as the amount of sulfonate group increases; (ii) the equilibrium constant does not appear as a sensitive parameter to the amount of sulfonate group on the surface of the microspheres; and (iii) the values of the fitting parameters obtained from FSTA may be indicative of a mismatch between the equilibrium separation of the intermolecular interaction and the distance between the adsorption sites. The exhaustive study presented here has shown that FSTA model is a good one considering the complexity of the physical situation, which is intended to be described and could be more useful in interpreting experimental data of adsorption of molecules with different sizes and shapes. PMID:23084559

  6. Adsorption-desorption characteristics of lead in variable charge soils.

    PubMed

    Yang, J Y; Yang, X E; He, Z L; Chen, G C; Shentu, J L; Li, T Q

    2004-01-01

    Adsorption desorption processes of Pb at contaminated levels in two variable charge soils were investigated. The red soil (RAR) developed on the Arenaceous rock (clayey, mixed siliceous thermic typic Dystrochrept) adsorbed more Pb2+ than the red soil (REQ) derived from the Quaternary red earths (clayey, kaolinitic thermic plinthite Aquult). The maximum adsorption values (Xm) that were obtained from the simple Langmuir model were 52.6 mmol Pb2+ kg(-1) soil and 29.9 mmol Pb2+ kg(-1) soil, respectively, for the RAR and REQ. Adsorption of Pb2+ decreased soil pH by 1.10 unit for the RAR soil and 1.21 unit for the REQ soil at the highest loading. The adsorption equilibrium pH of RAR was higher than that of REQ at the same Pb2+ concentration. The distribution coefficient (Kd) of Pb in the soils decreased exponentially with increasing Pb2+ loading. Most of the adsorbed Pb2+ in the soils was not desorbed in the 0.01 mol L(-1) NaNO3 solution. After five successive extractions with NaNO3, only 0-11% of the total adsorbed Pb2+ in the RAR soil was desorbed and the corresponding value of the REQ soil was 0-19%, indicating that the RAR soil had a greater affinity for Pb2+ than the REQ soil at the same Pb2+ loading. Different mechanisms might be involved in Pb2+ adsorption/desorption at different levels of Pb2+ loading and between the two soils.

  7. 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)

  8. 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...

  9. PSA-detected prostate cancer and the potential for dedifferentiation--estimating the proportion capable of progression.

    PubMed

    Pashayan, Nora; Pharoah, Paul; Neal, David E; Hamdy, Freddie; Donovan, Jenny; Martin, Richard M; Greenberg, David; Duffy, Stephen W

    2011-03-15

    The aims were to determine whether prostate-specific antigen (PSA)-detected prostate cancers progress to higher Gleason score during the preclinical screen-detectable phase, and, if so, to estimate the proportion of tumours with progressive potential. We developed two multi-state Markov chain models to represent the natural history of two tumour populations, one with (Model I) and the other without (Model II) the potential for progression. For each, we derived the transition rates between the states and used these estimates to calculate the expected prevalence of preclinical low and intermediate-to-high Gleason score prostate cancers, using data from the Prostate Testing for Cancer and Treatment (ProtecT) study on 2,310 prostate cancers detected by PSA testing in 71,511 men 50-69 years. We compared the expected prevalence for each tumour population to that of the observed based on ProtecT and the European Randomised Study on Screening for Prostate Cancer (ERSPC)-Rotterdam Centre's first round screening data, the latter allowing independent assessment of the two models. The overall expected proportion of low Gleason score tumours was 0.56 under Model I and 0.81 under Model II, whereas the observed proportion based on either ProtecT or ERSPC-Rotterdam was 0.69. Using the observed prevalence from ERSPC-Rotterdam, we estimated that 22, 33 and 66% of the tumours in men aged 55-59, 60-64 and 65-69 years, respectively, had the potential for progression in the preclinical phase. PSA-detected prostate cancers are a mixture of progressive and non-progressive tumours with respect to Gleason score. The former may potentially benefit from screening. Identifying cancers with the potential for progression is important to target screening. PMID:20499312

  10. PSA-NCAM is Expressed in Immature, but not Recently Generated, Neurons in the Adult Cat Cerebral Cortex Layer II

    PubMed Central

    Varea, Emilio; Belles, Maria; Vidueira, Sandra; Blasco-Ibáñez, José M.; Crespo, Carlos; Pastor, Ángel M.; Nacher, Juan

    2011-01-01

    Neuronal production persists during adulthood in the dentate gyrus and the olfactory bulb, where substantial numbers of immature neurons can be found. These cells can also be found in the paleocortex layer II of adult rodents, but in this case most of them have been generated during embryogenesis. Recent reports have described the presence of similar cells, with a wider distribution, in the cerebral cortex of adult cats and primates and have suggested that they may develop into interneurons. The objective of this study is to verify this hypothesis and to explore the origin of these immature neurons in adult cats. We have analyzed their distribution using immunohistochemical analysis of the polysialylated form of the neural cell adhesion molecule (PSA-NCAM) and their phenotype using markers of mature neurons and different interneuronal populations. Additionally, we have explored the origin of these cells administering 5′bromodeoxyuridine (5′BrdU) during adulthood. Immature neurons were widely dispersed in the cerebral cortex layers II and upper III, being specially abundant in the piriform and entorhinal cortices, in the ventral portions of the frontal and temporoparietal lobes, but relatively scarce in dorsal regions, such as the primary visual areas. Only a small fraction of PSA-NCAM expressing cells in layer II expressed the mature neuronal marker NeuN and virtually none of them expressed calcium binding proteins or neuropeptides. By contrast, most, if not all of these cells expressed the transcription factor Tbr-1, specifically expressed by pallium-derived principal neurons, but not CAMKII, a marker of mature excitatory neurons. Absence of PSA-NCAM/5′BrdU colocalization suggests that, as in rats, these cells were not generated during adulthood. Together, these results indicate that immature neurons in the adult cat cerebral cortex layer II are not recently generated and that they may differentiate into principal neurons. PMID:21415912

  11. Multilayer adsorption by Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Molina-Mateo, J.; Salmerón Sánchez, M.; Monleón Pradas, M.; Torregrosa Cabanilles, C.

    2012-10-01

    Adsorption phenomena are characterized by models that include free parameters trying to reproduce experimental results. In order to understand the relationship between the model parameters and the material properties, the adsorption of small molecules on a crystalline plane surface has been simulated using the bond fluctuation model. A direct comparison between the Guggenheim-Anderson-de Boer (GAB) model for multilayer adsorption and computer simulations allowed us to establish correlations between the adsorption model parameters and the simulated interaction potentials.

  12. Identification of Lipoprotein Homologues of Pneumococcal PsaA in the Equine Pathogens Streptococcus equi and Streptococcus zooepidemicus

    PubMed Central

    Harrington, Dean J.; Greated, Joanne S.; Chanter, Neil; Sutcliffe, Iain C.

    2000-01-01

    Streptococcus equi and Streptococcus zooepidemicus are major etiological agents of upper and lower airway disease in horses. Despite the considerable animal suffering and economic burden associated with these diseases, the factors that contribute to the virulence of these equine pathogens have not been extensively investigated. Here we demonstrate the presence of a homologue of the Streptococcus pneumoniae PsaA protein in both of these equine pathogens. Inhibition of signal peptide processing by the antibiotic globomycin confirmed the lipoprotein nature of the mature proteins, and surface exposure was confirmed by their release from intact cells by mild trypsinolysis. PMID:10992520

  13. 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.

  14. ADSORPTIVE MEDIA TECHNOLOGIES: MEDIA SELECTION

    EPA Science Inventory

    The presentation provides information on six items to be considered when selecting an adsorptive media for removing arsenic from drinking water; performance, EBCT, pre-treatment, regeneration, residuals, and cost. Each item is discussed in general and data and photographs from th...

  15. Interfacial adsorption in ternary alloys

    SciTech Connect

    Huang, C.; Cruz, M.O. de la; Voorhees, P.W.

    1999-11-26

    Interfaces of A-B-C ternary alloys decomposed into two and three phases are studied. The effect of the gradient energy coefficients {bar {kappa}}{sub II}, I = A, B, C, on the interface composition profiles of ternary alloys is examined. The adsorption of component C in ternary alloys is obtained numerically by finding steady-state solutions of the nonlinear Cahn-Hilliard equations and by solving the two Euler-Lagrange equations resulting from minimizing the interfacial energy, and analytically near the critical point. It is found that the solutions from both numerical methods are identical for a two-phase system. In symmetric ternary systems (equal interaction energy between each pair of components) with a minority component C, the gradient energy coefficient of C, {bar {kappa}}{sub CC}, can have a very strong influence on the degree of adsorption. In the {alpha} and {beta} two-phase regions, where {alpha} and {beta} are the phases rich in the majority components A and B, respectively, as {bar {kappa}}{sub CC} increases, the adsorption of the minority component C in the {alpha} and {beta} interfaces decreases. Near a critical point, however, the degree of adsorption of minority component C is independent of the gradient energy coefficient.

  16. 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...

  17. HIGH CHLOROPHYLL FLUORESCENCE145 Binds to and Stabilizes the psaA 5′ UTR via a Newly Defined Repeat Motif in Embryophyta

    PubMed Central

    Torabi, Salar; Lezhneva, Lina; Arif, Muhammad Asif; Frank, Wolfgang

    2015-01-01

    The seedling-lethal Arabidopsis thaliana high chlorophyll fluorescence145 (hcf145) mutation leads to reduced stability of the plastid tricistronic psaA-psaB-rps14 mRNA and photosystem I (PSI) deficiency. Here, we genetically mapped the HCF145 gene, which encodes a plant-specific, chloroplast-localized, modular protein containing two homologous domains related to the polyketide cyclase family comprising 37 annotated Arabidopsis proteins of unknown function. Two further highly conserved and previously uncharacterized tandem repeat motifs at the C terminus, herein designated the transcript binding motif repeat (TMR) domains, confer sequence-specific RNA binding capability to HCF145. Homologous TMR motifs are often found as multiple repeats in quite diverse proteins of green and red algae and in the cyanobacterium Microcoleus sp PCC 7113 with unknown function. HCF145 represents the only TMR protein found in vascular plants. Detailed analysis of hcf145 mutants in Arabidopsis and Physcomitrella patens as well as in vivo and in vitro RNA binding assays indicate that HCF145 has been recruited in embryophyta for the stabilization of the psaA-psaB-rps14 mRNA via specific binding to its 5′ untranslated region. The polyketide cyclase-related motifs support association of the TMRs to the psaA RNA, presumably pointing to a regulatory role in adjusting PSI levels according to the requirements of the plant cell. PMID:26307378

  18. Molybdate adsorption from steel slag eluates by subsoils.

    PubMed

    Matern, K; Rennert, T; Mansfeldt, T

    2013-11-01

    Steel slags are industrial by-products which are generated in large amounts worldwide, e.g. 150-230×10(6) Mg in 2012, and which are partly used for construction. Molybdenum (Mo) can be added during steel processing in order to harden the steel. The objective of this study was to evaluate the adsorption behaviour of molybdate (MoO4(2-)) from slag eluates in subsoils. Molybdate batch adsorption experiments were carried out with eluates obtained from two different kinds of steel slags (i) LD slag (Linz-Donawitz operation, LDS) and (ii) electric arc furnace slag (EAF) to assess the risk that may arise from the contamination of groundwater by the leaching of molybdate. Six different subsoils were chosen in order to provide a wide range of chemical properties (pH 4.0-7.6; dithionite-extractable Fe 0.73-14.7 g kg(-1)). Molybdate adsorption experiments were carried out at the pH of the steel slag eluates (pH 11-12) as well as at pH values adjusted to the soil pH. The data were evaluated with the Freundlich equation. Molybdate adsorption exhibited a maximum near pH 4 for steel slag eluates adjusted to the soil pH, and decreased rapidly with increasing pH until adsorption was virtually zero at pH>11. Adsorption was greater for soils with high amounts of dithionite-extractable Fe oxides. The extent and behaviour of molybdate adsorption from both eluates was similar. After a reaction time of 24h, the pH of the EAF slag eluate was lower than that of the LD steel slag eluate, which was caused by different acid buffer capacities. Some soils were able to decrease the pH of the EAF slag eluates by about 4 pH units, enhancing the adsorption of molybdate. Transport simulations indicated that molybdate discharge is low in acidic soils.

  19. Kinetic Batch Soil Adsorption Studies of 2, 4-dinitroanisole (DNAN)

    NASA Astrophysics Data System (ADS)

    Arthur, J.; Mark, N. W.; Taylor, S.; Brusseau, M. L.; Dontsova, K.

    2014-12-01

    Currently the explosive 2, 4, 6- trinitrotoluene (TNT) is used as a main ingredient in munitions; however the compound has failed to meet sensitivity requirements. The replacement compound being tested is 2, 4-dinitroanisole (DNAN). DNAN is less sensitive to shock, high temperatures, and has good detonation characteristics. However, DNAN is more soluble than TNT, which can influence transport and fate behavior and thus bioavailability and exposure potential. DNAN has been shown to have some human and environmental toxicity. The objective of this study was to investigate the environmental fate of DNAN in soil, with a specific focus on sorption processes. Batch experiments were conducted using 11 soils collected from military installations located across the United States. The soils were characterized for pH, specific surface area, electrical conductivity, cation exchange capacity, and organic carbon content. Adsorption kinetic data determined at room temperature were fitted using the first order kinetic equation. Adsorption isotherms were fitted with linear and Freundlich isotherm equations. The magnitudes of the linear adsorption coefficients ranged from 0.6 to 6 cm3/g. Results indicated that the adsorption of DNAN is strongly dependent on the amount of organic carbon present in the soil.

  20. Tc-99 Adsorption on Selected Activated Carbons - Batch Testing Results

    SciTech Connect

    Mattigod, Shas V.; Wellman, Dawn M.; Golovich, Elizabeth C.; Cordova, Elsa A.; Smith, Ronald M.

    2010-12-01

    CH2M HILL Plateau Remediation Company (CHPRC) is currently developing a 200-West Area groundwater pump-and-treat system as the remedial action selected under the Comprehensive Environmental Response, Compensation, and Liability Act Record of Decision for Operable Unit (OU) 200-ZP-1. This report documents the results of treatability tests Pacific Northwest National Laboratory researchers conducted to quantify the ability of selected activated carbon products (or carbons) to adsorb technetium-99 (Tc-99) from 200-West Area groundwater. The Tc-99 adsorption performance of seven activated carbons (J177601 Calgon Fitrasorb 400, J177606 Siemens AC1230AWC, J177609 Carbon Resources CR-1240-AW, J177611 General Carbon GC20X50, J177612 Norit GAC830, J177613 Norit GAC830, and J177617 Nucon LW1230) were evaluated using water from well 299-W19-36. Four of the best performing carbons (J177606 Siemens AC1230AWC, J177609 Carbon Resources CR-1240-AW, J177611 General Carbon GC20X50, and J177613 Norit GAC830) were selected for batch isotherm testing. The batch isotherm tests on four of the selected carbons indicated that under lower nitrate concentration conditions (382 mg/L), Kd values ranged from 6,000 to 20,000 mL/g. In comparison. Under higher nitrate (750 mg/L) conditions, there was a measureable decrease in Tc-99 adsorption with Kd values ranging from 3,000 to 7,000 mL/g. The adsorption data fit both the Langmuir and the Freundlich equations. Supplemental tests were conducted using the two carbons that demonstrated the highest adsorption capacity to resolve the issue of the best fit isotherm. These tests indicated that Langmuir isotherms provided the best fit for Tc-99 adsorption under low nitrate concentration conditions. At the design basis concentration of Tc 0.865 µg/L(14,700 pCi/L), the predicted Kd values from using Langmuir isotherm constants were 5,980 mL/g and 6,870 mL/g for for the two carbons. These Kd values did not meet the target Kd value of 9,000 mL/g. Tests

  1. Off-gas Adsorption Model and Simulation - OSPREY

    SciTech Connect

    Veronica J Rutledge

    2013-10-01

    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. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes is expected to provide substantial cost savings and many technical benefits. To support this capability, a modeling effort focused on the off-gas treatment system of a used nuclear fuel recycling facility is in progress. 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 within Multi-physics Object Oriented Simulation Environment (MOOSE) developed at the Idaho National Laboratory (INL). Off-gas Separation and REcoverY (OSPREY) models the adsorption of offgas constituents for dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions. Inputs to the model include gas composition, sorbent and column properties, equilibrium and kinetic data, and inlet conditions. The simulation outputs component concentrations along the column length as a function of time from which breakthrough data can be obtained. The breakthrough data can be used to determine bed capacity, which in turn can be used to size columns. In addition to concentration data, the model predicts temperature along the column length as a function of time and pressure drop along the column length. A description of the OSPREY model, results from krypton adsorption modeling and plans for modeling the behavior of iodine, xenon, and tritium will be discussed.

  2. Summary of the GK15 ground‐motion prediction equation for horizontal PGA and 5% damped PSA from shallow crustal continental earthquakes

    USGS Publications Warehouse

    Graizer, Vladimir;; Kalkan, Erol

    2016-01-01

    We present a revised ground‐motion prediction equation (GMPE) for computing medians and standard deviations of peak ground acceleration (PGA) and 5% damped pseudospectral acceleration (PSA) response ordinates of the horizontal component of randomly oriented ground motions to be used for seismic‐hazard analyses and engineering applications. This GMPE is derived from the expanded Next Generation Attenuation (NGA)‐West 1 database (see Data and Resources; Chiou et al., 2008). The revised model includes an anelastic attenuation term as a function of quality factor (Q0) to capture regional differences in far‐source (beyond 150 km) attenuation, and a new frequency‐dependent sedimentary‐basin scaling term as a function of depth to the 1.5  km/s shear‐wave velocity isosurface to improve ground‐motion predictions at sites located on deep sedimentary basins. The new Graizer–Kalkan 2015 (GK15) model, developed to be simple, is applicable for the western United States and other similar shallow crustal continental regions in active tectonic environments for earthquakes with moment magnitudes (M) 5.0–8.0, distances 0–250 km, average shear‐wave velocities in the upper 30 m (VS30) 200–1300  m/s, and spectral periods (T) 0.01–5 s. Our aleatory variability model captures interevent (between‐event) variability, which decreases with magnitude and increases with distance. The mixed‐effect residuals analysis reveals that the GK15 has no trend with respect to the independent predictor parameters. Compared to our 2007–2009 GMPE, the PGA values are very similar, whereas spectral ordinates predicted are larger at T<0.2  s and they are smaller at longer periods.

  3. Bayesian Inference for Time Trends in Parameter Values: Case Study for the Ageing PSA Network of the European Commission

    SciTech Connect

    Dana L. Kelly; Albert Malkhasyan

    2010-06-01

    There is a nearly ubiquitous assumption in PSA that parameter values are at least piecewise-constant in time. As a result, Bayesian inference tends to incorporate many years of plant operation, over which there have been significant changes in plant operational and maintenance practices, plant management, etc. These changes can cause significant changes in parameter values over time; however, failure to perform Bayesian inference in the proper time-dependent framework can mask these changes. Failure to question the assumption of constant parameter values, and failure to perform Bayesian inference in the proper time-dependent framework were noted as important issues in NUREG/CR-6813, performed for the U. S. Nuclear Regulatory Commission’s Advisory Committee on Reactor Safeguards in 2003. That report noted that “industry lacks tools to perform time-trend analysis with Bayesian updating.” This paper describes an application of time-dependent Bayesian inference methods developed for the European Commission Ageing PSA Network. These methods utilize open-source software, implementing Markov chain Monte Carlo sampling. The paper also illustrates the development of a generic prior distribution, which incorporates multiple sources of generic data via weighting factors that address differences in key influences, such as vendor, component boundaries, conditions of the operating environment, etc.

  4. Ectopic expression of transcription factor AP-2δ in developing retina: effect on PSA-NCAM and axon routing.

    PubMed

    Li, Xiaodong; Monckton, Elizabeth A; Godbout, Roseline

    2014-04-01

    Retinal ganglion cells transmit the visual signal from the retina to the brain. We have previously shown that the activator protein 2 (AP-2)δ (TFAP2D) transcription factor is expressed in one third of ganglion cells in developing retina suggesting a specialized role for these AP-2δ-expressing cells. Here, we address the role of AP-2δ in retina by in ovo electroporation of RCAS/AP-2δ retroviral constructs into the eyes of chick embryos at day 2 of gestation. Ectopic expression of AP-2δ does not affect lineage differentiation in the developing retina. However, immunostaining of retinal tissue with markers associated with axonal growth such as growth-associated protein 43 and polysialic acid-neural cell adhesion molecule (PSA-NCAM) demonstrates axonal misrouting and abnormal axonal bundling. Treatment of AP-2δ-misexpressing retinal cell cultures with endoneuraminidase, an enzyme that removes PSA from NCAM, decreases AP-2δ-induced axonal bundling. Our data suggest a role for AP-2δ in polysialylation of NCAM, with ectopic expression of AP-2δ resulting in premature bundling of emerging axons and misrouting of axons. We propose that expression of AP-2δ in a subset of ganglion cells contributes to the fine-tuning of axonal growth in the developing retina. PMID:24188130

  5. A comparison of two anesthesia methods for the surgical removal of maxillary third molars: PSA nerve block technique vs. local infiltration technique

    PubMed Central

    2014-01-01

    Objectives: The purpose of this study was to compare the effect of PSA block injection with infiltration technique regarding local anesthesia for surgical extraction of upper third molar. Material and Methods: A prospective, intra individual, single-blind randomized controlled trial was designed to study the severity of pain during injection and after surgical extraction of the bilaterally and symmetrically similar upper third molar in a total of 53 patients, in addition to evaluating the need to repeat the injection and requirement of post operative anti-inflammatory tablets. Result: Although the average pain score for all studied times in PSA side was lower than the average pain score in infiltration technique, repeated statistical measures demonstrated that no significant pain reduction occurred in the two techniques. Conclusion: The both tested methods have the same statistic equivalence for the surgical extraction of maxillary third molars. Key words:Surgical extraction, maxillary third molars, PSA block, infiltration. PMID:24596629

  6. Adsorption of organic chemicals in soils.

    PubMed Central

    Calvet, R

    1989-01-01

    This paper presents a review on adsorption of organic chemicals on soils sediments and their constituents. The first part of this review deals with adsorption from gas and liquid phases and gives a discussion on the physical meaning of the shape of adsorption isotherms. Results show that no general rules can be proposed to describe univocally the relation between the shape of isotherms and the nature of adsorbate-adsorbent system. Kinetics of adsorption is discussed through the description of various models. Theoretical developments exist both for the thermodynamics and the kinetics of adsorption, but there is a strong need for experimental results. Possible adsorption mechanisms are ion exchange, interaction with metallic cations, hydrogen bonds, charge transfers, and London-van der Waals dispersion forces/hydrophobic effect. However, direct proofs of a given mechanism are rare. Several factors influence adsorption behavior. Electronic structure of adsorbed molecules, properties of adsorbents, and characteristics of the liquid phase are discussed in relation to adsorption. Such properties as water solubility, organic carbon content of adsorbing materials, and the composition of the liquid phase are particularly important. Evaluation of adsorption can be obtained through either laboratory measurements or use of several correlations. Adsorption measurements must be interpreted, taking into account treatment of adsorbent materials, experimental conditions, and secondary phenomena such as degradations. Correlations between adsorption coefficients and water-octanol partition coefficient or water solubility are numerous. They may be useful tools for prediction purposes. Relations with transport, bioavailability, and degradation are described. PMID:2695323

  7. 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

  8. Adsorption of organic chemicals in soils.

    PubMed

    Calvet, R

    1989-11-01

    This paper presents a review on adsorption of organic chemicals on soils sediments and their constituents. The first part of this review deals with adsorption from gas and liquid phases and gives a discussion on the physical meaning of the shape of adsorption isotherms. Results show that no general rules can be proposed to describe univocally the relation between the shape of isotherms and the nature of adsorbate-adsorbent system. Kinetics of adsorption is discussed through the description of various models. Theoretical developments exist both for the thermodynamics and the kinetics of adsorption, but there is a strong need for experimental results. Possible adsorption mechanisms are ion exchange, interaction with metallic cations, hydrogen bonds, charge transfers, and London-van der Waals dispersion forces/hydrophobic effect. However, direct proofs of a given mechanism are rare. Several factors influence adsorption behavior. Electronic structure of adsorbed molecules, properties of adsorbents, and characteristics of the liquid phase are discussed in relation to adsorption. Such properties as water solubility, organic carbon content of adsorbing materials, and the composition of the liquid phase are particularly important. Evaluation of adsorption can be obtained through either laboratory measurements or use of several correlations. Adsorption measurements must be interpreted, taking into account treatment of adsorbent materials, experimental conditions, and secondary phenomena such as degradations. Correlations between adsorption coefficients and water-octanol partition coefficient or water solubility are numerous. They may be useful tools for prediction purposes. Relations with transport, bioavailability, and degradation are described.

  9. 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

  10. Tritium Specific Adsorption Simulation Utilizing the OSPREY Model

    SciTech Connect

    Veronica Rutledge; Lawrence Tavlarides; Ronghong Lin; Austin Ladshaw

    2013-09-01

    During the processing of used nuclear fuel, volatile radionuclides will be discharged to the atmosphere if no recovery processes are in place to limit their release. The volatile radionuclides of concern are 3H, 14C, 85Kr, and 129I. Methods are being developed, via adsorption and absorption unit operations, to capture these radionuclides. It is necessary to model these unit operations to aid in the evaluation of technologies and in the future development of an advanced used nuclear fuel processing plant. A collaboration between Fuel Cycle Research and Development Offgas Sigma Team member INL and a NEUP grant including ORNL, Syracuse University, and Georgia Institute of Technology has been formed to develop off gas models and support off gas research. This report is discusses the development of a tritium specific adsorption model. Using the OSPREY model and integrating it with a fundamental level isotherm model developed under and experimental data provided by the NEUP grant, the tritium specific adsorption model was developed.

  11. Adsorption air cleaning from ozone.

    PubMed

    Baltrenas, Pranas; Paliulis, Dainius; Vasarevicius, Saulius; Simaitis, Ramutis

    2003-01-01

    Not much has been written about air cleaning from ozone. The aim of this paper was to demonstrate the possibility of adsorption air cleaning from ozone. The second aim was to investigate the dependence of the efficiency of ozone removal from the air on the height of the adsorber layer and on concentrations of ozone, and to obtain empirical formulas for calculating the efficiency of ozone treatment. Equipment for air cleaning from ozone and nitrogen and sulphur dioxides is suggested.

  12. Studies on Vapor Adsorption Systems

    NASA Technical Reports Server (NTRS)

    Shamsundar, N.; Ramotowski, M.

    1998-01-01

    The project consisted of performing experiments on single and dual bed vapor adsorption systems, thermodynamic cycle optimization, and thermal modeling. The work was described in a technical paper that appeared in conference proceedings and a Master's thesis, which were previously submitted to NASA. The present report describes some additional thermal modeling work done subsequently, and includes listings of computer codes developed during the project. Recommendations for future work are provided.

  13. Fitness variables and the lipid profile in United States astronauts

    NASA Technical Reports Server (NTRS)

    Berry, M. A.; Squires, W. G.; Jackson, A. S.

    1980-01-01

    The study examines the relationship between several measures of fitness and the lipid profile in United States astronauts. Data were collected on 89 astronauts, previously selected (PSA) and newly selected (NSA), during their annual physical examinations. Several similarities were seen in the two groups. The PSA (mean age of 46.1) had a lower maximum oxygen capacity (41.7 ml kg/min vs. 47.5 ml kg/min); when adjusted for age, it was no different from the NSA (mean age 33.5). The PSA had similar body composition with 15.7% - lower than expected for age. The lipid profiles of the two groups were basically the same with the differences being a function of age. Compared to a normative population, the astronauts had similar cholesterols, lower triglycerides, and higher HDLs. The astronaut profiles were generally more favorable than the age-matched controls, which is felt to be a result of the self-supervised conditioning program and annual preventive medicine consultation and education.

  14. Characterization of metal adsorption variability in a sand and gravel aquifer, Cape Cod, Massachusetts, U.S.A

    USGS Publications Warehouse

    Fuller, C.C.; Davis, J.A.; Coston, J.A.; Dixon, E.

    1996-01-01

    Several geochemical properties of an aquifer sediment that control metal-ion adsorption were investigated to determine their potential use as indicators of the spatial variability of metal adsorption. Over the length of a 4.5-m-long core from a sand and gravel aquifer, lead (Pb2+) and zinc (Zn2+) adsorption at constant chemical conditions (pH 5.3) varied by a factor of 2 and 4, respectively. Pb2+ and Zn2+ were adsorbed primarily by Fe- and Al-oxide coatings on quartz-grain surfaces. Per unit surface area, both Pb2+ and Zn2+ adsorption were significantly correlated with the amount of Fe and Al that dissolved from the aquifer material in a partial chemical extraction. The variability in conditional binding constants for Pb2+ and Zn2+ adsorption (log KADS) derived from a simple non-electrostatic surface complexation model were also predicted by extracted Fe and Al normalized to surface area. Because the abundance of Fe- and Al-oxide coatings that dominate adsorption does not vary inversely with grain size by a simple linear relationship, only a weak, negative correlation was found between the spatial variability of Pb2+ adsorption and grain size in this aquifer. The correlation between Zn2+ adsorption and grain size was not significant. Partial chemical extractions combined with surface-area measurements have potential use for estimating metal adsorption variability in other sand and gravel aquifers of negligible carbonate and organic carbon content.

  15. Powder-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

    DOEpatents

    Janke, Christopher J.; Dai, Sheng; Oyola, Yatsandra

    2016-05-03

    A powder-based adsorbent and a related method of manufacture are provided. The powder-based adsorbent includes polymer powder with grafted side chains and an increased surface area per unit weight to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. A method for forming the powder-based adsorbent includes irradiating polymer powder, grafting with polymerizable reactive monomers, reacting with hydroxylamine, and conditioning with an alkaline solution. Powder-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

  16. Foam-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

    DOEpatents

    Janke, Christopher J.; Dai, Sheng; Oyola, Yatsandra

    2015-06-02

    Foam-based adsorbents and a related method of manufacture are provided. The foam-based adsorbents include polymer foam with grafted side chains and an increased surface area per unit weight to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. A method for forming the foam-based adsorbents includes irradiating polymer foam, grafting with polymerizable reactive monomers, reacting with hydroxylamine, and conditioning with an alkaline solution. Foam-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

  17. Protein adsorption onto ceramic surfaces.

    PubMed

    Takami, Y; Yamane, S; Makinouchi, K; Otsuka, G; Glueck, J; Benkowski, R; Nosé, Y

    1998-04-01

    Ceramics seldom have been used as blood-contacting materials. However, alumina ceramic (Al2O3) and polyethylene are incorporated into the pivot bearings of the Gyro centrifugal blood pump. This material combination was chosen based on the high durability of the materials. Due to the stagnant flow that often occurs in a continuous flow condition inside a centrifugal pump, pivot bearing system is extremely critical. To evaluate the thombogenicity of pivot bearings in the Gyro pump, this study sought to investigate protein adsorption, particularly albumin, IgG, fibrinogen, and fibronectin onto ceramic surfaces. Al2O3 and silicon carbide ceramic (SiC) were compared with polyethylene (PE) and polyvinylchloride (PVC). Bicinchoninic acid (BCA) protein assay revealed that the amount of adsorbed proteins onto Al2O3 and SiC was significantly less than that on PVC. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated that numerous proteins adsorbed onto PVC compared to PE, Al2O3, and SiC. Identification of adsorbed proteins by Western immunoblotting revealed that the adsorption of albumin was similar on all four materials tested. Western immunoblotting also indicated lesser amounts of IgG, fibrinogen, and fibronectin on Al2O3 and SiC than on PE and PVC. In conclusion, ceramics (Al2O3 and SiC) are expected to be thromboresistant from the viewpoint of protein adsorption. PMID:9511095

  18. Critical adsorption and colloidal interaction in multi-component liquids

    NASA Astrophysics Data System (ADS)

    Alam, Sharmine; Mukhopadhyay, Ashis

    2014-03-01

    We studied critical adsorption on colloidal nanoparticles in binary liquid mixture of 2,6 lutidine + water by using fluorescence correlation spectroscopy (FCS). Our results indicated that the adsorbed film thickness is of the order of correlation length associated with concentration fluctuations. The excess adsorption per unit area increases following a power law in reduced temperature with an exponent of -1, which is the mean-field value for the bulk susceptibility exponent. The measurements at higher particle volume fractions, where phenomena such as the particle-particle interaction, self-assembly, ternary phase separation become important will be presented. Acknowledgements are made to the Donors of the American Chemical Society Petroleum Research fund (PRF # 51694-ND10) for support of this research.

  19. Adsorption-desorption characteristics of cadmium in variable charge soils.

    PubMed

    He, Zhen-Li; Xu, Hai-Ping; Zhu, Ying-Mei; Yang, Xiao-E; Chen, Guo-Chao

    2005-01-01

    Cadmium (Cd) has received considerable attention because of its association with various human health problems. The behavior of adsorption-desorption of Cd at contaminated levels in two variable charge soils were investigated. The red soil (RAR) developed on the Arenaceous rock (clayey, mixed siliceous thermic typic Dystrochrept) adsorbed more Cd2+ than the red soil (REQ) derived from the Quaternary red earths (clayey, kaolinitic thermic plinthite Aquult). The characteristics of Cd adsorption could be described by the Freundlich equation (r2 = 0.997 and 0.989, respectively, for the RAR and REQ) and the simple Langmuir adsorption equation (r2 = 0.985 and 0.977, respectively, for the RAR and REQ). The maximum adsorption values (Xm) that were obtained from the simple Langmuir model were 36.23 mmol Cd2+ kg(-1) soil and 31.15 mmol Cd2+ kg(-1) soil, respectively for the RAR and REQ. Adsorption of Cd2+ decreased soil pH by 1.28 unit for the RAR soil and 1.23 unit for the REQ soil at the highest loading. The distribution coefficient (kd) of Cd in the soil decreased exponentially with increasing Cd2+ loading. The adsorption of cadmium in the two variable charge soils was characterized by a rapid process that lasted approximately 15 min, followed by a slower but longer period. 85.5% and 79.4% of the added Cd were adsorbed within two hours by the RAR and REQ soil, respectively. More Cd2+ was adsorbed at 10 degrees C than at 25 degrees C or 40 degrees C. After five successive desorptions with 0.01 mol L(-1) NaNO3 solution, 53.3% of the total adsorbed Cd2+ in the RAR soil was desorbed and the corresponding value of the REQ soil was 46.5%, indicating that the RAR soil had a lower affinity for Cd2+ than the REQ soil at the same Cd2+ loading. PMID:15792301

  20. Off-gas adsorption model and simulation - OSPREY

    SciTech Connect

    Rutledge, V.J.

    2013-07-01

    A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes is expected to provide substantial cost savings and many technical benefits. To support this capability, a modeling effort focused on the off-gas treatment system of a used nuclear fuel recycling facility is in progress. 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 within Multi-physics Object Oriented Simulation Environment (MOOSE) developed at the Idaho National Laboratory (INL). Off-gas Separation and Recovery (OSPREY) models the adsorption of offgas constituents for dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions. Inputs to the model include gas composition, sorbent and column properties, equilibrium and kinetic data, and inlet conditions. The simulation outputs component concentrations along the column length as a function of time from which breakthrough data can be obtained. The breakthrough data can be used to determine bed capacity, which in turn can be used to size columns. In addition to concentration data, the model predicts temperature along the column length as a function of time and pressure drop along the column length. A description of the OSPREY model, results from krypton adsorption modeling and plans for modeling the behavior of iodine, xenon, and tritium will be discussed. (author)

  1. U(VI) adsorption on aquifer sediments at the Hanford Site.

    PubMed

    Um, Wooyong; Serne, R Jeffrey; Brown, Christopher F; Last, George V

    2007-08-15

    Aquifer sediments collected via split-spoon sampling in two new groundwater wells in the 200-UP-1 operable unit at the Hanford Site were characterized and showed typical Ringold Unit E Formation properties dominated by gravel and sand. High iron-oxide content in Fe oxide/clay coatings caused the highest U(VI) adsorption as quantified by batch K(d) values, indicating iron oxides are the key solid adsorbent in the 200-UP-1 sediments that affect U(VI) fate and mobility. Even though U(VI) adsorption on the gravel-sized fraction of the sediments is considered to be negligible, careful characterization should be conducted to determine U(VI) adsorption on gravel, because of presence of Fe oxides coatings and diffusion-controlled adsorption into the gravel particles' interior surfaces. A linear adsorption isotherm was observed up to 10(-6) M (238 microg/L) of total U(VI) concentration in batch U(VI) adsorption tests with varying total U(VI) concentrations in spiked groundwater. U(VI) adsorption decreased with increasing concentrations of dissolved carbonate, because strong anionic aqueous uranium-carbonate complexes formed at high pH and high alkalinity conditions. Noticeable uranium desorption hysteresis was observed in a flow-through column experiment, suggesting that desorption K(d) values for aged uranium-contaminated sediments at the Hanford Site can be larger than adsorption K(d) values determined in short-term laboratory experiments and slow uranium release from contaminated sediments into the groundwater is expected.

  2. Adsorption of goethite onto quartz and kaolinite

    USGS Publications Warehouse

    Goldberg, M.C.; Weiner, Eugene R.; Boymel, P.M.

    1984-01-01

    The adsorption of colloidal goethite onto quartz and kaolinite substrates has been studied as a function of pH and NaCl concentration. Goethite adsorption was measured quantitatively by Fourier-transform infrared spectroscopy. The results indicate that adsorption onto both substrates is due primarily to coulombic forces; however, the pH dependence of adsorption is very different for the two substrates. This is explained by the fact that the surface charge on quartz is entirely pH-dependent, while kaolinite has surface faces which carry a permanent negative charge. Adsorption of goethite on to kaolinite increases markedly with increasing NaCl concentration, while adsorption onto quartz is relatively independent of NaCl concentration. This can be explained by the influence of NaCl concentration upon the development of surface charge on the substrates. A method is described for separating surface-bound goethite from free goethite.

  3. 'PSA-SPN' - A Parameter Sensitivity Analysis Method Using Stochastic Petri Nets: Application to a Production Line System

    SciTech Connect

    Labadi, Karim; Saggadi, Samira; Amodeo, Lionel

    2009-03-05

    The dynamic behavior of a discrete event dynamic system can be significantly affected for some uncertain changes in its decision parameters. So, parameter sensitivity analysis would be a useful way in studying the effects of these changes on the system performance. In the past, the sensitivity analysis approaches are frequently based on simulation models. In recent years, formal methods based on stochastic process including Markov process are proposed in the literature. In this paper, we are interested in the parameter sensitivity analysis of discrete event dynamic systems by using stochastic Petri nets models as a tool for modelling and performance evaluation. A sensitivity analysis approach based on stochastic Petri nets, called PSA-SPN method, will be proposed with an application to a production line system.

  4. Complete PSA Response Following Stereotactic Ablative Radiotherapy for a Bony Metastasis in the Setting of Castrate-Resistant Prostate Cancer

    PubMed Central

    Rodrigues, George

    2015-01-01

    A majority of patients with castrate-resistant prostate cancer ultimately develop distant metastases, with bone being the most common site of spread. Classically, systemic therapy has been considered the standard of care for patients with metastatic cancer. Emerging evidence, however, suggests that an intermediate oligometastatic state, between limited disease and widespread metastases, exists; theoretically, with locally ablative treatment, patients may be curable. We describe a complete PSA response following aggressive management, using stereotactic body radiotherapy (SBRT), of an oligometastatic spine lesion in the setting of castrate-resistant prostate cancer (CRPC). This case report supports the use of SBRT in oligometastatic CRPC and suggests that management of limited metastases may provide good long-term outcomes in well-selected patients. PMID:26623220

  5. Improved porous silicon (P-Si) microarray based PSA (prostate specific antigen) immunoassay by optimized surface density of the capture antibody

    PubMed Central

    Lee, SangWook; Kim, Soyoun; Malm, Johan; Jeong, Ok Chan; Lilja, Hans; Laurell, Thomas

    2014-01-01

    Enriching the surface density of immobilized capture antibodies enhances the detection signal of antibody sandwich microarrays. In this study, we improved the detection sensitivity of our previously developed P-Si (porous silicon) antibody microarray by optimizing concentrations of the capturing antibody. We investigated immunoassays using a P-Si microarray at three different capture antibody (PSA - prostate specific antigen) concentrations, analyzing the influence of the antibody density on the assay detection sensitivity. The LOD (limit of detection) for PSA was 2.5ngmL−1, 80pgmL−1, and 800fgmL−1 when arraying the PSA antibody, H117 at the concentration 15µgmL−1, 35µgmL−1 and 154µgmL−1, respectively. We further investigated PSA spiked into human female serum in the range of 800fgmL−1 to 500ngmL−1. The microarray showed a LOD of 800fgmL−1 and a dynamic range of 800 fgmL−1 to 80ngmL−1 in serum spiked samples. PMID:24016590

  6. Active photosynthesis in cyanobacterial mutants with directed modifications in the ligands for two iron-sulfur clusters on the PsaC protein of photosystem I.

    PubMed Central

    Mannan, R M; He, W Z; Metzger, S U; Whitmarsh, J; Malkin, R; Pakrasi, H B

    1996-01-01

    The PsaC protein of the Photosystem I (PSI) complex in thylakoid membranes coordinates two [4Fe-4S] clusters, FA and FB. Although it is known that PsaC participates in electron transfer to ferredoxin, the pathway of electrons through this protein is unknown. To elucidate the roles of FA and FB, we created two site-directed mutant strains of the cyanobacterium Anabaena variabilis ATCC 29413. In one mutant, cysteine 13, a ligand for FB was replaced by an aspartic acid (C13D); in the other mutant, cysteine 50, a ligand for FA was modified similarly (C50D). Low-temperature electron paramagnetic resonance studies demonstrated that the C50D mutant has a normal FB center and a modified FA center. In contrast, the C13D strain has normal FA, but failed to reveal any signal from FB. Room-temperature optical studies showed that C13D has only one functional electron acceptor in PsaC, whereas two such acceptors are functional in the C50D and wild-type strains. Although both mutants grow under photoautotrophic conditions, the rate of PSI-mediated electron transfer in C13D under low light levels is about half that of C50D or wild type. These data show that (i) FB is not essential for the assembly of the PsaC protein in PSI and (ii) FB is not absolutely required for electron transfer from the PSI reaction center to ferredoxin. PMID:8617228

  7. Free energy landscapes for the thermodynamic understanding of adsorption-induced deformations and structural transitions in porous materials

    NASA Astrophysics Data System (ADS)

    Bousquet, D.; Coudert, F.-X.; Boutin, A.

    2012-07-01

    Soft porous crystals are flexible metal-organic frameworks that respond to physical stimuli such as temperature, pressure, and gas adsorption by large changes in their structure and unit cell volume. While they have attracted a lot of interest, molecular simulation methods that directly couple adsorption and large structural deformations in an efficient manner are still lacking. We propose here a new Monte Carlo simulation method based on non-Boltzmann sampling in (guest loading, volume) space using the Wang-Landau algorithm, and show that it can be used to fully characterize the adsorption properties and the material's response to adsorption at thermodynamic equilibrium. We showcase this new method on a simple model of the MIL-53 family of breathing materials, demonstrating its potential and contrasting it with the pitfalls of direct, Boltzmann simulations. We furthermore propose an explanation for the hysteretic nature of adsorption in terms of free energy barriers between the two metastable host phases.

  8. Stereotactic Body Radiotherapy as Monotherapy or Post-External Beam Radiotherapy Boost for Prostate Cancer: Technique, Early Toxicity, and PSA Response

    SciTech Connect

    Jabbari, Siavash; Weinberg, Vivian K.; Kaprealian, Tania; Hsu, I-Chow; Ma Lijun; Chuang, Cynthia; Descovich, Martina; Shiao, Stephen; Shinohara, Katsuto; Roach, Mack; Gottschalk, Alexander R.

    2012-01-01

    Purpose: High dose rate (HDR) brachytherapy has been established as an excellent monotherapy or after external-beam radiotherapy (EBRT) boost treatment for prostate cancer (PCa). Recently, dosimetric studies have demonstrated the potential for achieving similar dosimetry with stereotactic body radiotherapy (SBRT) compared with HDR brachytherapy. Here, we report our technique, PSA nadir, and acute and late toxicity with SBRT as monotherapy and post-EBRT boost for PCa using HDR brachytherapy fractionation. Patients and Methods: To date, 38 patients have been treated with SBRT at University of California-San Francisco with a minimum follow-up of 12 months. Twenty of 38 patients were treated with SBRT monotherapy (9.5 Gy Multiplication-Sign 4 fractions), and 18 were treated with SBRT boost (9.5 Gy Multiplication-Sign 2 fractions) post-EBRT and androgen deprivation therapy. PSA nadir to date for 44 HDR brachytherapy boost patients with disease characteristics similar to the SBRT boost cohort was also analyzed as a descriptive comparison. Results: SBRT was well tolerated. With a median follow-up of 18.3 months (range, 12.6-43.5), 42% and 11% of patients had acute Grade 2 gastrourinary and gastrointestinal toxicity, respectively, with no Grade 3 or higher acute toxicity to date. Two patients experienced late Grade 3 GU toxicity. All patients are without evidence of biochemical or clinical progression to date, and favorably low PSA nadirs have been observed with a current median PSA nadir of 0.35 ng/mL (range, <0.01-2.1) for all patients (0.47 ng/mL, range, 0.2-2.1 for the monotherapy cohort; 0.10 ng/mL, range, 0.01-0.5 for the boost cohort). With a median follow-up of 48.6 months (range, 16.4-87.8), the comparable HDR brachytherapy boost cohort has achieved a median PSA nadir of 0.09 ng/mL (range, 0.0-3.3). Conclusions: Early results with SBRT monotherapy and post-EBRT boost for PCa demonstrate acceptable PSA response and minimal toxicity. PSA nadir with SBRT boost

  9. Adsorption thermodynamics of Methylene Blue onto bentonite.

    PubMed

    Hong, Song; Wen, Cheng; He, Jing; Gan, Fuxing; Ho, Yuh-Shan

    2009-08-15

    The effect of temperature on the equilibrium adsorption of Methylene Blue dye from aqueous solution using bentonite was investigated. The equilibrium adsorption data were analyzed using three widely applied isotherms: Langmuir, Freundlich, and Redlich-Peterson. A non-linear method was used for comparing the best fit of the isotherms. Best fit was found to be Redlich-Peterson isotherm. Thermodynamic parameters, such as DeltaG degrees, DeltaH degrees, and DeltaS degrees were calculated using adsorption equilibrium constant obtained from the Langmuir isotherm. Results suggested that the Methylene Blue adsorption on bentonite was a spontaneous and endothermic process.

  10. Adsorption of phenol on wood surfaces

    NASA Astrophysics Data System (ADS)

    Mamleeva, N. A.; Lunin, V. V.

    2016-03-01

    Adsorption of phenol on aspen and pine wood is investigated. It is shown that adsorption isotherms are described by the Langmuir model. The woods' specific surface areas and adsorption interaction constants are determined. It is found that the sorption of phenol on surfaces of aspen and pine is due to Van der Waals interactions ( S sp = 45 m2/godw for aspen and 85 m2/godw for pine). The difference between the adsorption characteristics is explained by properties of the wood samples' microstructures.

  11. Physical adsorption strength in open systems.

    PubMed

    Knippenberg, M Todd; Stuart, Steven J; Cooper, Alan C; Pez, G P; Cheng, Hansong

    2006-11-23

    For a physical adsorption system, the distances of adsorbates from the surface of a substrate can vary significantly, depending on particle loading and interatomic interactions. Although the total adsorption energy is quantified easily, the normalized, per-particle adsorption energies are more ambiguous if some of these particles are far away from the surface and are interacting only weakly with the substrate. A simple analytical procedure is proposed to characterize the distance dependence of the physisorption strength and effective adsorption capacity. As an example, the method is utilized to describe H2 physisorption in a finite bundle of single-walled carbon nanotubes. PMID:17107125

  12. 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.

  13. Charcoal/Nitrogen Adsorption Cryocooler

    NASA Technical Reports Server (NTRS)

    Bard, Steven

    1987-01-01

    Refrigerator with no wear-related moving parts produces 0.5 W of cooling at 118 K. When fully developed, refrigerator needs no electrical power, and life expectancy of more than 10 yr, operates unattended to cool sensitive infrared detectors for long periods. Only moving parts in adsorption cryocooler are check valves. As charcoal is cooled in canister, gas pressure drops, allowing inlet check valve to open and admit more nitrogen. When canister is heated, pressure rises, closing inlet valve and eventually opening outlet valve.

  14. Moisture adsorption in optical coatings

    NASA Technical Reports Server (NTRS)

    Macleod, H. Angus

    1988-01-01

    The thin film filter is a very large aperture component which is exceedingly useful because of its small size, flexibility and ease of mounting. Thin film components, however, do have defects of performance and especially of stability which can cause problems in systems, particularly where long-term measurements are being made. Of all of the problems, those associated with moisture absorption are the most serious. Moisture absorption occurs in the pore-shaped voids inherent in the columnar structure of the layers. Ion-assisted deposition is a promising technique for substantially reducing moisture adsorption effects in thin film structures.

  15. Depletion of Polysialic Acid from Neural Cell Adhesion Molecule (PSA-NCAM) Increases CA3 Dendritic Arborization and Increases Vulnerability to Excitotoxicity

    PubMed Central

    McCall, Trudy; Weil, Zachary M.; Nacher, Juan; Bloss, Erik B.; El Marouf, Abderrahman; Rutishauser, Urs; McEwen, Bruce S.

    2012-01-01

    Chronic immobilization stress (CIS) shortens apical dendritic trees of CA3 pyramidal neurons in the hippocampus of the male rat, and dendritic length may be a determinant of vulnerability to stress. Expression of the polysialylated form of neural cell adhesion molecule (PSA-NCAM) in the hippocampal formation is increased by stress, while PSA removal by Endoneuraminidase-N (endo-N) is known to cause the mossy fibers to defasciculate and synapse ectopically in their CA3 target area. We show here that enzymatic removal of PSA produced a remarkable expansion of dendritic arbors of CA3 pyramidal neurons, with a lesser effect in CA1. This expansion eclipsed the CIS-induced shortening of CA3 dendrites, with the expanded dendrites of both no-stress-endo-N and CIS-endo-N rats being longer than those in no-stress-control rats and much longer than those in CIS-control rats. As predicted by the hypothesis that ENDO-N-induced dendritic expansion might increase vulnerability to excitotoxic challenge, systemic injection with kainic acid, showed markedly increased neuronal degeneration, as assessed by fluorojade B histochemistry, in rats that had been treated with ENDO-N compared to vehicle treated rats throughout the entire hippocampal formation. PSA removal also exacerbated the CIS-induced reduction in body weight and abolished effects of CIS on NPY and NR2B mRNA levels. These findings support the hypothesis that CA3 arbor plasticity plays a protective role during prolonged stress and clarify the role of PSA-NCAM in stress-induced dendritic plasticity. PMID:23219884

  16. PSA-Based Screening Outcomes, Dietary Heterocyclic Amine Exposure, and Prostate Cancer Risk in African Americans: Annual Report (Year 1 of 3)

    SciTech Connect

    Bogen, K T

    2006-01-18

    Prostate cancer (PC) is the second leading cause of male U.S. cancer deaths, with African-Americans having the highest rate of PC mortality worldwide, as well as more abnormal results from screening tests that correlate with current or eventual PC. A 3-year prospective clinic-based study is studying the performance of current (PSA and DRE) vs. (% free PSA) clinical biomarkers of PC risk in 400 African-American men 50 to 70 years of age who undergo PC screening in Oakland, CA (East Bay San Francisco area), as well as possible association of PC screening results for these men with their dietary exposures to the cancer-causing heterocyclic amine, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) that forms when meat is cooked. This study expands an ongoing NIH-funded study (by the same research team) to add a new %-free-PSA test, results of which will be compared with PSA/DRE results and PhIP exposures estimated by dietary interviews. For 392 men studied under the NIH protocol, an odds ratio (95% CL) of 32 (3.2, 720) for highly elevated PSA ({ge}20 ng/mL) was observed in the highest 15% vs. the lower 50% of estimated daily PhIP intakes. Approximately 100 additional men have completed participation in the expanded NIH/DOD-supported study. This study will help define the potential value of improved screening and dietary/behavioral intervention to reduce PC risk, namely, prevention of PhIP intake by avoiding overcooked meats.

  17. 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

  18. Adsorptive separation in bioprocess engineering

    SciTech Connect

    Huang, E.W.Y.

    1987-01-01

    The invention and development of an energy-efficient separation technique for recovery of desired chemicals from biomass conversion would greatly enhance the economic viability of this bioprocess. Adsorptive separation of several chemicals from aqueous solution was studied in this thesis. The desired species were recovered from the dilute aqueous solution by using crosslinked polyvinylpyridine resin to effect selective sorption. The sorbed chemicals were then removed from the resin by either thermal regeneration or elution with some appropriate desorbents. The effects of temperature, pH value, and solute concentration on resin swelling were investigated. The adsorption equilibrium isotherms, resin capacities and resin selectivities of methanol, ethanol, 1-propanol, isopropanol, glycerol, acetone, 1-butanol, tert-butanol, and 2,3-butanediol were determined to study the homologies. Furthermore, acetic acid, butyric acid, hydrochloric acid, lactic acid, and sulfuric acid were recovered from very dilute aqueous solutions. The concentration of the sorbed chemical in the stationary phase can be many times higher than in the mobile phase for some acids. Finally, different types of equilibrium isotherms were used to fit the experimental data. A mathematical model was developed by using the theory of interference to predict the breakthrough curves and the process efficiency to provide information for large-scale process design and development.

  19. Molecular Insights into the pH-Dependent Adsorption and Removal of Ionizable Antibiotic Oxytetracycline by Adsorbent Cyclodextrin Polymers

    PubMed Central

    Zhang, Yu; Cai, Xiyun; Xiong, Weina; Jiang, Hao; Zhao, Haitong; Yang, Xianhai; Li, Chao; Fu, Zhiqiang; Chen, Jingwen

    2014-01-01

    Effects of pH on adsorption and removal efficiency of ionizable organic compounds (IOCs) by environmental adsorbents are an area of debate, because of its dual mediation towards adsorbents and adsorbate. Here, we probe the pH-dependent adsorption of ionizable antibiotic oxytetracycline (comprising OTCH2+, OTCH±, OTC−, and OTC2−) onto cyclodextrin polymers (CDPs) with the nature of molecular recognition and pH inertness. OTCH± commonly has high adsorption affinity, OTC− exhibits moderate affinity, and the other two species have negligible affinity. These species are evidenced to selectively interact with structural units (e.g., CD cavity, pore channel, and network) of the polymers and thus immobilized onto the adsorbents to different extents. The differences in adsorption affinity and mechanisms of the species account for the pH-dependent adsorption of OTC. The mathematical equations are derived from the multiple linear regression (MLR) analysis of quantitatively relating adsorption affinity of OTC at varying pH to adsorbent properties. A combination of the MLR analysis for OTC and molecular recognition of adsorption of the species illustrates the nature of the pH-dependent adsorption of OTC. Based on this finding, γ-HP-CDP is chosen to adsorb and remove OTC at pH 5.0 and 7.0, showing high removal efficiency and strong resistance to the interference of coexisting components. PMID:24465975

  20. Adsorptive removal of nitrilotris(methylenephosphonic acid) antiscalant from membrane concentrates by iron-coated waste filtration sand.

    PubMed

    Boels, L; Tervahauta, T; Witkamp, G J

    2010-10-15

    Iron-coated waste filtration sand was investigated as a low-cost adsorbent for the removal of nitrilotris(methylenephosphonic acid) (NTMP) from membrane concentrates. The adsorption of this phosphonate-based antiscalant on this material was measured and compared with two commercially available anion exchange resins and activated carbon. Comprehensive adsorption experiments were conducted in several synthetic concentrate solutions and in a concentrate collected from a full scale nano-filtration brackish water desalination plant. The effect of pH, ionic strength and the presence of competitive anions on the equilibrium adsorption were investigated. The results showed that, in contrast to the anion exchange resins, the adsorption on coated filtration sand is not suppressed at increasing ionic strength and is much less affected by the competitive anions carbonate and sulphate. The adsorption decreased slightly when the pH was raised from 7.0 to 8.0. The adsorption isotherms in the real nano-filtration concentrate, measured in the concentration interval of 5-50 mg dm(-1) NTMP, showed that the maximum adsorption capacity of coated filtration sand was 4.06 mg g(-1). The adsorption capacity per unit mass of the adsorbents at low NTMP concentration (12.5 mg dm(-3)) followed the decreasing order Amberlite IRA-410>coated filtration sand>Amberlite IRA-900>Norit SAE Super. This demonstrates that the use of iron-coated waste filtration sand offers a promising means for the removal of NTMP from membrane concentrates.

  1. Removal of Uranium in Drinking Water: Brimac Environmental Services, Inc. Brimac HA 216 Adsorptive Media

    EPA Science Inventory

    The Brimac HA 216 Adsorptive Media was tested for uranium (U) removal from a drinking water source (well water) at Grappone Toyota located in Bow, New Hampshire. The HA 216 media is a hydroxyapatite-based material. A pilot unit, consisting of a TIGG Corporation Cansorb® C-5 ste...

  2. Adsorption of Congo red from aqueous solutions onto Ca-bentonite.

    PubMed

    Lian, Lili; Guo, Liping; Guo, Chunjing

    2009-01-15

    The ability of Ca-bentonite to remove Congo red dye from aqueous solutions has been carried out as a function of contact time, temperature (20-50 degrees C), pH (5-10) and concentration (50-200mgL(-1)). An amount of 0.2g of Ca-bentonite could remove more than 90.0% of the dye from 100mgL(-1) Congo red dye solution for the temperature range studied here. The amount of dye adsorbed per unit weight of Ca-bentonite increased from 23.25 to 85.29mgg(-1) with increasing concentration from 50 to 200mgL(-1), but it had a little change with temperature and decreased slightly with increasing pH. The kinetics of adsorption in view of three kinetic models, i.e., the pseudo-first-order Lagergren model, the pseudo-second-order model and the intraparticle diffusion model, was discussed. The pseudo-second-order kinetic model described the adsorption of Congo red on Ca-bentonite very well. Analysis of adsorption results obtained at 20 degrees C showed that the adsorption pattern on Ca-bentonite followed the Freundlich isotherms. It was indicative of the heterogeneity of the adsorption sites on the clay particles. From thermodynamic studies, it was seen that the adsorption was spontaneous and endothermic. PMID:18487014

  3. Enhanced performance in gas adsorption and Li ion batteries by docking Li(+) in a crown ether-based metal-organic framework.

    PubMed

    Bai, Linyi; Tu, Binbin; Qi, Yi; Gao, Qiang; Liu, Dong; Liu, Zhizhou; Zhao, Lingzhi; Li, Qiaowei; Zhao, Yanli

    2016-02-18

    Incorporating supramolecular interaction units, crown ether rings, into metal-organic frameworks enables the docking of metal ions through complexation for enhanced performance in H2 and CO2 adsorption and lithium ion batteries.

  4. Enhanced performance in gas adsorption and Li ion batteries by docking Li(+) in a crown ether-based metal-organic framework.

    PubMed

    Bai, Linyi; Tu, Binbin; Qi, Yi; Gao, Qiang; Liu, Dong; Liu, Zhizhou; Zhao, Lingzhi; Li, Qiaowei; Zhao, Yanli

    2016-02-18

    Incorporating supramolecular interaction units, crown ether rings, into metal-organic frameworks enables the docking of metal ions through complexation for enhanced performance in H2 and CO2 adsorption and lithium ion batteries. PMID:26785426

  5. 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...

  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. [Adsorption of a dye by sludges and the roles of extracellular polymeric substances].

    PubMed

    Kong, Wang-sheng; Liu, Yan

    2007-12-01

    This paper investigated the adsorption of a dye, acid turquoise blue A, by four kinds of sludges including activated sludge, anaerobic sludge, dried activated sludge, and dried anaerobic sludge, respectively. The roles of extracellular polymeric substances (EPS) including the soluble EPS (SEPS) and bound EPS (BEPS) for the biosorption of activated sludge and anaerobic sludge were further studied. Results show that the relation between four kinds of sludge adsorption amount and remained concentration of the dye fitted well both Freundlich model (R2: 0.921-0.995) and Langmuir model (R2: 0.958-0.993), but not quite fitted BET model (R2: 0.07-0.863). The adsorption capability of dried anaerobic sludge ranked the highest, and dried activated sludge was the lowest. According to Langmuir isotherm, the maximum adsorption amount of dried anaerobic, anaerobic, activated, and dried activated sludge was 104 mg/g, 86 mg/g, 65 mg/g, 20 mg/g, respectively. The amount of the dye found in EPS for both activated sludge and anaerobic sludge were over 50%, illustrating that EPS adsorption was predominant in adsorption of the dye by sludge. The amount of adsorbed dye by BEPS was greater than that by SEPS for anaerobic sludge, but for activated sludge the result was quite opposite. The amount of adsorbed dye by unit mass SEPS was much higher than the corresponding values of BEPS for both sludges. The average amount of adsorbed dye by unit mass SEPS was 52 times of the corresponding value of BEPS for activated sludge, and 10 times for anaerobic sludge. The relation between adsorption amount of dye by BEPS from anaerobic sludge and remained concentration of the dye in mixed liquor was best fitted to Langmuir model (R2: 0.9986).

  8. Adsorption of xenon and krypton on shales

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    A method that uses a mass spectrometer as a manometer is employed in the measurement of Xe and Kr adsorption parameters on shales and related samples, where gas partial pressures were lower than 10 to the -11th atm, corresponding adsorption coverages are only small fractions of a monolayer, and Henry's Law behavior is expected and observed. Results show heats of adsorption in the 2-7 kcal/mol range, and Henry constants at 0-25 C of 1 cu cm STP/g per atmosphere are extrapolated. Although the adsorption properties obtained are variable by sample, the range obtained suggests that shales may be capable of an equilibrium adsorption with modern air high enough to account for a significant fraction of the atmospheric inventory of Xe, and perhaps even of Kr. This effect will nevertheless not account for the factor-of-25 defficiency of atmospheric Xe, in comparison with the planetary gas patterns observed in meteorites.

  9. Adsorption kinetics of methyl violet onto perlite.

    PubMed

    Doğan, Mehmet; Alkan, Mahir

    2003-01-01

    This study examines adsorption kinetics and activation parameters of methyl violet on perlite. The effect of process parameters like contact time, concentration of dye, temperature and pH on the extent of methyl violet adsorption from solution has been investigated. Results of the kinetic studies show that the adsorption reaction is first order with respect to dye solution concentration with activation energy of 13.2 kJ mol(-1). This low activation energy value indicates that the adsorption reaction is diffusion controlled. The activation parameters using Arrhenius and Eyring equations have been calculated. Adsorption increases with increase of variables such as contact time, initial dye concentration, temperature and pH.

  10. Water Adsorption in Porous Metal-Organic Frameworks and Related Materials

    SciTech Connect

    Furukawa, H; Gandara, F; Zhang, YB; Jiang, JC; Queen, WL; Hudson, MR; Yaghi, OM

    2014-03-19

    Water adsorption in porous materials is important for many applications such as dehumidification, thermal batteries, and delivery of drinking water in remote areas. In this study, we have identified three criteria for achieving high performing porous materials for water adsorption. These criteria deal with condensation pressure of water in the pores, uptake capacity, and recyclability and water stability of the material. In search of an excellently performing porous material, we have studied and compared the water adsorption properties of 23 materials, 20 of which are metal organic frameworks (MOFs). Among the MOFs are 10 zirconium(IV) MOFs with a subset of these, MOF-801-SC (single crystal form), -802, -805, -806, -808, -812, and -841 reported for the first time. MOF-801-P (microcrystalline powder form) was reported earlier and studied here for its water adsorption properties. MOF-812 was only made and structurally characterized but not examined for water adsorption because it is a byproduct of MOF-841 synthesis. All the new zirconium MOFs are made from the Zr6O4(OH)(4)(-CO2)(n) secondary building units (n = 6, 8, 10, or 12) and variously shaped carboxyl organic linkers to make extended porous frameworks. The permanent porosity of all 23 materials was confirmed and their water adsorption measured to reveal that MOF-801-P and MOF-841 are the highest performers based on the three criteria stated above; they are water stable, do not lose capacity after five adsorption/desorption cycles, and are easily regenerated at room temperature. An X-ray single-crystal study and a powder neutron diffraction study reveal the position of the water adsorption sites in MOF-801 and highlight the importance of the intermolecular interaction between adsorbed water molecules within the pores.

  11. Prostate Health Index (Phi) and Prostate Cancer Antigen 3 (PCA3) significantly improve prostate cancer detection at initial biopsy in a total PSA range of 2-10 ng/ml.

    PubMed

    Ferro, Matteo; Bruzzese, Dario; Perdonà, Sisto; Marino, Ada; Mazzarella, Claudia; Perruolo, Giuseppe; D'Esposito, Vittoria; Cosimato, Vincenzo; Buonerba, Carlo; Di Lorenzo, Giuseppe; Musi, Gennaro; De Cobelli, Ottavio; Chun, Felix K; Terracciano, Daniela

    2013-01-01

    Many efforts to reduce prostate specific antigen (PSA) overdiagnosis and overtreatment have been made. To this aim, Prostate Health Index (Phi) and Prostate Cancer Antigen 3 (PCA3) have been proposed as new more specific biomarkers. We evaluated the ability of phi and PCA3 to identify prostate cancer (PCa) at initial prostate biopsy in men with total PSA range of 2-10 ng/ml. The performance of phi and PCA3 were evaluated in 300 patients undergoing first prostate biopsy. ROC curve analyses tested the accuracy (AUC) of phi and PCA3 in predicting PCa. Decision curve analyses (DCA) were used to compare the clinical benefit of the two biomarkers. We found that the AUC value of phi (0.77) was comparable to those of %p2PSA (0.76) and PCA3 (0.73) with no significant differences in pairwise comparison (%p2PSA vs phi p = 0.673, %p2PSA vs. PCA3 p = 0.417 and phi vs. PCA3 p = 0.247). These three biomarkers significantly outperformed fPSA (AUC = 0.60), % fPSA (AUC = 0.62) and p2PSA (AUC = 0.63). At DCA, phi and PCA3 exhibited a very close net benefit profile until the threshold probability of 25%, then phi index showed higher net benefit than PCA3. Multivariable analysis showed that the addition of phi and PCA3 to the base multivariable model (age, PSA, %fPSA, DRE, prostate volume) increased predictive accuracy, whereas no model improved single biomarker performance. Finally we showed that subjects with active surveillance (AS) compatible cancer had significantly lower phi and PCA3 values (p<0.001 and p = 0.01, respectively). In conclusion, both phi and PCA3 comparably increase the accuracy in predicting the presence of PCa in total PSA range 2-10 ng/ml at initial biopsy, outperforming currently used %fPSA.

  12. [Effect of compound Chinese traditional medicine PC-SPES II in inhibiting proliferation of human prostate cancer cell LNCaP and on expressions of AR and PSA].

    PubMed

    Zhang, Bi-yan; Li, Yu-feng; Lai, Yun; Li, Yun-sen; Chen, Zi-jun

    2015-03-01

    To investigate the effect of compound Chinese traditional medicine PC-SPES II I in inhibiting proliferation of human prostate cancer cell LNCaP based on the androgen receptor (AR) signaling pathway. The effect of PC-SPES II on LNCaP cell proliferation was detected by MTT assay. According to the findings, at the mass concentration of 180-1 440 mg x L(-1), PC-SPES II significantly inhibited the proliferation of LNCaP cells; the IC50 of PC-SPES II at 24 h and 48 h were 311.48, 199.01 mg x L(-1), respectively. The flow Cytometry detection showed 240 mg x L(-1) PC-SPES II arrested cells in G2/M phase, and an obvious apoptotic peak appeared before G0/G1 peak and rose over time. Meanwhile, Hoechst 33258 staining revealed apoptotic cellular morphology. Annexin V-FITC/PI staining manifested an increase in apoptotic cell ratio at the PC-SPES II concentration of 480 mg x L(-1) in a dose dependent manner. The prostate specific antigen (PSA) secretion of LNCaP cells was tested by PSA ELISA kit. Besides, compared with 25 mg x L(-1) Bic, 480 mg x L(-1) PC-SPES II significantly reduced the cell secretion of PSA. The AR and PSA mRNA and protein expressions were detected by qRT-PCR and Western blot. According to the results, after the induction of LNCaP cells with synthetic androgen 25 μg x L(-1) R1881, 240-480 mg x L(-1) PC-SPES II notably down-regulated the AR and PSA mRNA and protein expressions and inhibited the translocation of AR from cytoplasm to nucleus. In summary, PC-SPES II significantly can inhibit the in vitro proliferation of LNCaP cells and arrest cell cycle arrest in G2/M phase. Its mechanism may be associated with the down-regulation of the AR and PSA expressions and the inhibition of AR nuclear translocation.

  13. Temperature Swing Adsorption Compressor Development

    NASA Technical Reports Server (NTRS)

    Finn, John E.; Mulloth, Lila M.; Affleck, Dave L.

    2001-01-01

    Closing the oxygen loop in an air revitalization system based on four-bed molecular sieve and Sabatier reactor technology requires a vacuum pump-compressor that can take the low-pressure CO, from the 4BMS and compress and store for use by a Sabatier reactor. NASA Ames Research Center proposed a solid-state temperature-swing adsorption (TSA) compressor that appears to meet performance requirements, be quiet and reliable, and consume less power than a comparable mechanical compressor/accumulator combination. Under this task, TSA compressor technology is being advanced through development of a complete prototype system. A liquid-cooled TSA compressor has been partially tested, and the rest of the system is being fabricated. An air-cooled TSA compressor is also being designed.

  14. PERFORMANCE AND DURABILITY OF THE PSA PEUGEOT CITROEN'S DPF SYSTEM ON A TAXI FLEET IN THE PARIS AREA

    SciTech Connect

    COROLLER, P; PLASSAT, G

    2003-08-24

    The use of Diesel engines has strongly increased during the last years and now represents 40% of the sales in Europe and up to 50% of the number of cars in circulation for some countries. This success is linked not only to the economical aspect of the use of such vehicles, but also to the recent technological improvements of these engines. The new technical solutions (high pressure direct injection, turbocharger) have indeed allowed the increase of these engine performances while decreasing their fuel consumption, pollutant emissions and noise level. From an environment point of view, Diesel engines are nevertheless penalized by their particulates and NOx emissions. The study and the treatment of the particulate, highly criticized for their potential impact on health, are the subject of numerous works of characterizations and developments. PSA Peugeot Citroen has recently (2000) launched its particulate filter technology on several types of vehicles (500,000 vehicles with DPF have been sold today). In order to evaluate the durability of this technology over a long period of time, a study program has been set-up by ADEME (French Environmental Agency), IFP Powertrain, PSA Peugeot Citroen and Taxis G7 (a Parisian taxis Company). The objective is to study the evolution of five taxis and their after-treatment system performances over 80,000km mileage--which corresponds to the recommended mileage before the first DPF maintenance--in hard urban driving conditions, as well over 120,000km, after the DPF maintenance and remanufacturing. More specifically, the following evaluations are being performed at regular intervals (around 20,000km): regulated gaseous pollutant emissions on NEDC cycle, particulate emissions and unregulated pollutant emissions. The results obtained until now have not shown any degradation of the particulate filter efficiency (more than 90%). This paper presents the methodology set-up, and the explanation of the first results obtained. Indeed, a more

  15. Modeling the adsorption of mixed gases based on pure gas adsorption properties

    NASA Astrophysics Data System (ADS)

    Tzabar, N.; Holland, H. J.; Vermeer, C. H.; ter Brake, H. J. M.

    2015-12-01

    Sorption-based Joule-Thomson (JT) cryocoolers usually operate with pure gases. A sorption-based compressor has many benefits; however, it is limited by the pressure ratios it can provide. Using a mixed-refrigerant (MR) instead of a pure refrigerant in JT cryocoolers allows working at much lower pressure ratios. Therefore, it is attractive using MRs in sorption- based cryocoolers in order to reduce one of its main limitations. The adsorption of mixed gases is usually investigated under steady-state conditions, mainly for storage and separation processes. However, the process in a sorption compressor goes through various temperatures, pressures and adsorption concentrations; therefore, it differs from the common mixed gases adsorption applications. In order to simulate the sorption process in a compressor a numerical analysis for mixed gases is developed, based on pure gas adsorption characteristics. The pure gas adsorption properties have been measured for four gases (nitrogen, methane, ethane, and propane) with Norit-RB2 activated carbon. A single adsorption model is desired to describe the adsorption of all four gases. This model is further developed to a mixed-gas adsorption model. In future work more adsorbents will be tested using these four gases and the adsorption model will be verified against experimental results of mixed-gas adsorption measurements.

  16. Arsenic Adsorption Equilibrium Concentration and Adsorption Rate of Activated Carbon Coated with Ferric-Aluminum Hydroxides

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Sugita, H.; Oguma, T.; Hara, J.; Takahashi, S.

    2015-12-01

    In some areas of developing countries, ground or well water contaminated with arsenic has been reluctantly used as drinking water. It is highly desirable that effective and inexpensive arsenic removal agents should be developed and provided to reduce the potential health risk. Previous studies demonstrated that activated carbon coated with ferric-aluminum hydroxides (Fe-Al-C) has high adsorptive potential for removal of arsenic. In this study, a series of experiments using Fe-Al-C were carried to discuss adsorption equilibrium time, adsorption equilibrium concentration and adsorption rate of arsenic for Fe-Al-C. Fe-Al-C used in this study was provided by Astec Co., Ltd. Powder reagent of disodium hydrogen arsenate heptahydrate was dissolved into ion-exchanged water. The solution was then further diluted with ion-exchanged water to be 1 and 10 mg/L as arsenic concentration. The pH of the solution was adjusted to be around 7 by adding HCl and/or NaOH. The solution was used as artificial arsenic contaminated water in two types of experiments (arsenic adsorption equilibrium and arsenic adsorption rate tests). The results of the arsenic equilibrium tests were showed that a time period of about 3 days to reach apparent adsorption equilibrium for arsenic. The apparent adsorption equilibrium concentration and adsorbed amount of arsenic on Fe-Al-C adsorbent could be estimated by application of various adsorption isotherms, but the distribution coefficient of arsenic between solid and liquid varies with experimental conditions such as initial concentration of arsenic and addition concentration of adsorbent. An adsorption rate equation that takes into account the reduction in the number of effective adsorption sites on the adsorbent caused by the arsenic adsorption reaction was derived based on the data obtained from the arsenic adsorption rate tests.

  17. Adsorption of Candida rugosa lipase at water-polymer interface: The case of poly( DL)lactide

    NASA Astrophysics Data System (ADS)

    Kamel, Gihan; Bordi, Federico; Chronopoulou, Laura; Lupi, Stefano; Palocci, Cleofe; Sennato, Simona; Verdes, Pedro V.

    2011-12-01

    Insights into the interactions between biological macromolecules and polymeric surfaces are of great interest because of potential uses in developing biotechnologies. In this study we focused on the adsorption of a model lipolytic enzyme, Candida rugosa lipase (CRL), on poly-(D,L)-lactic acid (PDLLA) polymer with the aim to gain deeper insights into the interactions between the enzyme and the carrier. Such studies are of particular relevance in order to establish the optimal conditions for enzyme immobilization and its applications. We employed two different approaches; by analyzing the influence of adsorbed CRL molecules on the thermodynamic behavior of Langmuir films of PDLLA deposited at air-water interface, we gained interesting information on the molecular interactions between the protein and the polymer. Successively, by a systematic analysis of the adsorption of CRL on PDLLA nanoparticles, we showed that the adsorption of a model lipase, CRL, on PDLLA is described in terms of a Langmuir-type adsorption behavior. In this model, only monomolecular adsorption takes place (i.e. only a single layer of the protein adsorbs on the support) and the interactions between adsorbed molecules and surface are short ranged. Moreover, both the adsorption and desorption are activated processes, and the heat of adsorption (the difference between the activation energy for adsorption and desorption) is independent from the surface coverage of the adsorbing species. Finally, we obtained an estimate of the number of molecules of the protein adsorbed per surface unit on the particles, a parameter of a practical relevance for applications in biocatalysis, and a semi-quantitative estimate of the energies (heat of adsorption) involved in the adsorption process.

  18. 2010 Groundwater Monitoring Report Project Shoal Area, Corrective Action Unit 447

    SciTech Connect

    2011-02-01

    This report presents the 2010 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) at the Project Shoal Area (PSA) Subsurface Corrective Action Unit (CAU) 447 in Churchill County, Nevada. Responsibility for the environmental site restoration of the PSA was transferred from the DOE Office of Environmental Management to LM on October 1, 2006. The environmental restoration process and corrective action strategy for CAU 447 are conducted in accordance with the Federal Facility Agreement and Consent Order (FFACO 1996, as amended March 2010) entered into by DOE, the U.S. Department of Defense, and the State of Nevada. The corrective action strategy for the site includes monitoring in support of site closure. This report summarizes the results from the groundwater monitoring program during fiscal year 2010.

  19. Corrective Action Investigation Plan for Corrective Action Unit 447: Project Shoal Area, Nevada Subsurface Site

    SciTech Connect

    DOE /NV

    1998-11-01

    This Corrective Action Investigation Plan (CAIP) describes the US Department of Energy's (DOE's) continued environmental investigation of the subsurface Project Shoal Area (PSA) Corrective Action Unit (CAU) 447. The PSA is located in the Sand Springs Mountains in Churchill County, Nevada, about 48 kilometers (km) (30 miles [mi]) southeast of Fallon, Nevada. Project Shoal was part of the Vela Uniform Program which was conducted to improve the US' ability to detect, identify, and locate underground nuclear detonations. The test consisted of detonating a 12-kiloton nuclear device deep underground in granitic rock to determine whether seismic waves produced by an underground nuclear test could be differentiated from seismic waves produced by a naturally occurring earthquake. The test was a joint effort conducted by the US Atomic Energy Commission (AEC) and the US Department of Defense (DoD) in October 1963 (AEC, 1964).

  20. Augmentation of Cooling Output by Silica Gel-Water Adsorption Cycle Utilizing the Waste Heat of GHP

    NASA Astrophysics Data System (ADS)

    Homma, Hiroki; Araki, Nobuyuki

    The GHP (Gas engine Heat Pump) system is expected to have high energy-efficiency in utilizing the waste heat exhausted from a gas engine. In summer season, a silica gel-water adsorption cooling unit driven by the exhaust heat is considered as a cooling system for saving energy. In this work, an attempt was made to improve the COP of a silica gel-water adsorption cooling system by enhancing heat and mass transfer in the silica gel adsorption layer. A unit cell was introduced as a simplified model of adsorber for analyzing the phenomena of heat and mass transfer in the adsorbent. This cell was composed of a single tube with a silica gel layer bonded on its external surface. Optimization of heat and mass transfer characteristics for the unit cell was carried out by experimental and analytical approach.

  1. Adsorption of lead over graphite oxide.

    PubMed

    Olanipekun, Opeyemi; Oyefusi, Adebola; Neelgund, Gururaj M; Oki, Aderemi

    2014-01-24

    The adsorption efficiency and kinetics of removal of lead in presence of graphite oxide (GO) was determined using the Atomic Absorption Spectrophotometer (AAS). The GO was prepared by the chemical oxidation of graphite and characterized using FTIR, SEM, TGA and XRD. The adsorption efficiency of GO for the solution containing 50, 100 and 150 ppm of Pb(2+) was found to be 98%, 91% and 71% respectively. The adsorption ability of GO was found to be higher than graphite. Therefore, the oxidation of activated carbon in removal of heavy metals may be a viable option to reduce pollution in portable water.

  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.

  3. Thermodynamics of binary gas adsorption in nanopores.

    PubMed

    Dutta, Sujeet; Lefort, Ronan; Morineau, Denis; Mhanna, Ramona; Merdrignac-Conanec, Odile; Saint-Jalmes, Arnaud; Leclercq, Théo

    2016-09-21

    MCM-41 nanoporous silicas show a very high selectivity for monoalcohols over aprotic molecules during adsorption of a binary mixture in the gas phase. We present here an original use of gravimetric vapour sorption isotherms to characterize the role played by the alcohol hydrogen-bonding network in the adsorption process. Beyond simple selectivity, vapour sorption isotherms measured for various compositions help to completely unravel at the molecular level the step by step adsorption mechanism of the binary system in the nanoporous solid, from the first monolayers to the complete liquid condensation. PMID:27532892

  4. Adsorption in sparse networks. 2: Silica aerogels

    SciTech Connect

    Scherer, G.W.; Calas, S.; Sempere, R.

    1998-06-15

    The model developed in Part 1 is applied to nitrogen adsorption isotherms obtained for a series of silica aerogels whose densities are varied by partial sintering. The isotherms are adequately described by a cubic network model, with all of the pores falling in the mesopore range; the adsorption and desorption branches are fit by the same pore size distribution. For the least dense gels, a substantial portion of the pore volume is not detected by condensation. The model attributes this effect to the shape of the adsorbate/adsorptive interface, which can adopt zero curvature even in mesopores, because of the shape of the network.

  5. Adsorption affinity of anions on metal oxyhydroxides

    NASA Astrophysics Data System (ADS)

    Pechenyuk, S. I.; Semushina, Yu. P.; Kuz'mich, L. F.

    2013-03-01

    The dependences of anion (phosphate, carbonate, sulfate, chromate, oxalate, tartrate, and citrate) adsorption affinity anions from geometric characteristics, acid-base properties, and complex forming ability are generalized. It is shown that adsorption depends on the nature of both the anions and the ionic medium and adsorbent. It is established that anions are generally grouped into the following series of adsorption affinity reduction: PO{4/3-}, CO{3/2-} > C2O{4/2-}, C(OH)(CH2)2(COO){3/3-}, (CHOH)2(COO){2/2-} > CrO{4/2-} ≫ SO{4/2-}.

  6. Relationship between two year PSA nadir and biochemical recurrence in prostate cancer patients treated with iodine-125 brachytherap*

    PubMed Central

    Franca, Carlos Antônio da Silva; Vieira, Sérgio Lannes; Carvalho, Antonio Carlos Pires; Bernabe, Antonio Jose Serrano; Penna, Antonio Belmiro Rodrigues Campbell

    2014-01-01

    Objective To evaluate the relationship between two year PSA nadir (PSAn) after brachytherapy and biochemical recurrence rates in prostate cancer patients. Materials and Methods In the period from January 1998 to August 2007, 120 patients were treated with iodine-125 brachytherapy alone. The results analysis was based on the definition of biochemical recurrence according to the Phoenix Consensus. Results Biochemical control was observed in 86 patients (71.7%), and biochemical recurrence, in 34 (28.3%). Mean PSAn was 0.53 ng/ml. The mean follow-up was 98 months. The patients were divided into two groups: group 1, with two year PSAn < 0.5 ng/ml after brachytherapy (74 patients; 61.7%), and group 2, with two year PSAn ≥ 0.5 ng/ml after brachytherapy (46 patients; 38.3%). Group 1 presented biochemical recurrence in 15 patients (20.3%), and group 2, in 19 patients (43.2%) (p < 0.02). The analysis of biochemical disease-free survival at seven years, stratified by the two groups, showed values of 80% and 64% (p < 0.02), respectively. Conclusion Levels of two year PSAn ≥ 0.5 ng/ml after brachytherapy are strongly correlated with a poor prognosis. This fact may help to identify patients at risk for disease recurrence. PMID:25741055

  7. Albumin (BSA) Adsorption over Graphene in Aqueous Environment: Influence of Orientation, Adsorption Protocol, and Solvent Treatment.

    PubMed

    Vilhena, J G; Rubio-Pereda, Pamela; Vellosillo, Perceval; Serena, P A; Pérez, Rubén

    2016-02-23

    We report 150 ns explicit solvent MD simulations of the adsorption on graphene of albumin (BSA) in two orientations and using two different adsorption protocols, i.e., free and forced adsorption. Our results show that free adsorption occurs with little structural rearrangements. Even taking adsorption to an extreme, by forcing it with a 5 nN downward force applied during the initial 20 ns, we show that along a particular orientation BSA is able to preserve the structural properties of the majority of its binding sites. Furthermore, in all the cases considered in this work, the ibuprofen binding site has shown a strong resilience to structural changes. Finally, we compare these results with implicit solvent simulations and find that the latter predicts an extreme protein unfolding upon adsorption. The origin of this discrepancy is attributed to a poor description of the water entropic forces at interfaces in the implicit solvent methods.

  8. Albumin (BSA) Adsorption over Graphene in Aqueous Environment: Influence of Orientation, Adsorption Protocol, and Solvent Treatment.

    PubMed

    Vilhena, J G; Rubio-Pereda, Pamela; Vellosillo, Perceval; Serena, P A; Pérez, Rubén

    2016-02-23

    We report 150 ns explicit solvent MD simulations of the adsorption on graphene of albumin (BSA) in two orientations and using two different adsorption protocols, i.e., free and forced adsorption. Our results show that free adsorption occurs with little structural rearrangements. Even taking adsorption to an extreme, by forcing it with a 5 nN downward force applied during the initial 20 ns, we show that along a particular orientation BSA is able to preserve the structural properties of the majority of its binding sites. Furthermore, in all the cases considered in this work, the ibuprofen binding site has shown a strong resilience to structural changes. Finally, we compare these results with implicit solvent simulations and find that the latter predicts an extreme protein unfolding upon adsorption. The origin of this discrepancy is attributed to a poor description of the water entropic forces at interfaces in the implicit solvent methods. PMID:26799950

  9. A Nucleus-Encoded Chloroplast Protein Regulated by Iron Availability Governs Expression of the Photosystem I Subunit PsaA in Chlamydomonas reinhardtii1

    PubMed Central

    Lefebvre-Legendre, Linnka; Choquet, Yves; Kuras, Richard; Loubéry, Sylvain; Douchi, Damien; Goldschmidt-Clermont, Michel

    2015-01-01

    The biogenesis of the photosynthetic electron transfer chain in the thylakoid membranes requires the concerted expression of genes in the chloroplast and the nucleus. Chloroplast gene expression is subjected to anterograde control by a battery of nucleus-encoded proteins that are imported in the chloroplast, where they mostly intervene at posttranscriptional steps. Using a new genetic screen, we identify a nuclear mutant that is required for expression of the PsaA subunit of photosystem I (PSI) in the chloroplast of Chlamydomonas reinhardtii. This mutant is affected in the stability and translation of psaA messenger RNA. The corresponding gene, TRANSLATION OF psaA1 (TAA1), encodes a large protein with two domains that are thought to mediate RNA binding: an array of octatricopeptide repeats (OPR) and an RNA-binding domain abundant in apicomplexans (RAP) domain. We show that as expected for its function, TAA1 is localized in the chloroplast. It was previously shown that when mixotrophic cultures of C. reinhardtii (which use both photosynthesis and mitochondrial respiration for growth) are shifted to conditions of iron limitation, there is a strong decrease in the accumulation of PSI and that this is rapidly reversed when iron is resupplied. Under these conditions, TAA1 protein is also down-regulated through a posttranscriptional mechanism and rapidly reaccumulates when iron is restored. These observations reveal a concerted regulation of PSI and of TAA1 in response to iron availability. PMID:25673777

  10. A combined database related and de novo MS-identification of yeast mannose-1-phosphate guanyltransferase PSA1 interaction partners at different phases of batch cultivation

    NASA Astrophysics Data System (ADS)

    Parviainen, Ville; Joenväärä, Sakari; Peltoniemi, Hannu; Mattila, Pirkko; Renkonen, Risto

    2009-04-01

    Mass spectrometry-based proteomic research has become one of the main methods in protein-protein interaction research. Several high throughput studies have established an interaction landscape of exponentially growing Baker's yeast culture. However, many of the protein-protein interactions are likely to change in different environmental conditions. In order to examine the dynamic nature of the protein interactions we isolated the protein complexes of mannose-1-phosphate guanyltransferase PSA1 from Saccharomyces cerevisiae at four different time points during batch cultivation. We used the tandem affinity purification (TAP)-method to purify the complexes and subjected the tryptic peptides to LC-MS/MS. The resulting peak lists were analyzed with two different methods: the database related protein identification program X!Tandem and the de novo sequencing program Lutefisk. We observed significant changes in the interactome of PSA1 during the batch cultivation and identified altogether 74 proteins interacting with PSA1 of which only six were found to interact during all time points. All the other proteins showed a more dynamic nature of binding activity. In this study we also demonstrate the benefit of using both database related and de novo methods in the protein interaction research to enhance both the quality and the quantity of observations.

  11. Integrated adsorptive technique for efficient recovery of m-cresol and m-toluidine from actual acidic and salty wastewater.

    PubMed

    Chen, Da; Liu, Fuqiang; Zong, Lidan; Sun, Xiaowen; Zhang, Xiaopeng; Zhu, Changqing; Tao, Xuewen; Li, Aimin

    2016-07-15

    An integrated adsorptive technique combining an m-cresol adsorption unit, an acid retardation unit and an m-toluidine adsorption unit in sequence was designed to recover m-cresol and m-toluidine from highly acidic and salty m-cresol manufacturing wastewater. In the first column packed with hypercrosslinked polymeric resin (NDA-99), most m-cresol was captured through π-π and hydrogen-bonding interactions as well as the salting-out effect, while m-toluidine was not absorbed due to protonation. To separate acid from salt, an acid retardation unit was introduced successively to adsorb sulfuric acid by strong base anion exchange resin (201×7). After the acid retardation unit and mild neutralization reaction, the last column filled with NDA-99 was applied to trap neutral m-toluidine from the salty effluent. Moreover, the eluent of the acid retardation unit was utilized as the regenerant to recover m-toluidine, and the recycled high-acidity and low-salinity solution of m-toluidine was directly used to produce m-cresol as the raw material. Therefore, the proposed method not only efficiently recycled m-cresol and m-toluidine, but also reduced the consumption of alkali dramatically (saving 0.1628t/t wastewater). These findings will inspire design of integrated adsorptive techniques for treating complex organic wastewater with high efficiency and low cost. PMID:27037473

  12. Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test

    SciTech Connect

    Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee; Park, Jin-Kyu; Lee, Namhoon

    2013-10-15

    Highlights: • Equilibrium test was attempted to evaluate adsorption characteristics of siloxane. • L2 had higher removal efficiency in carbon compared to noncarbon adsorbents. • Total adsorption capacity of siloxane was 300 mg/g by coal activated carbon. • Adsorption characteristics rely on size of siloxane molecule and adsorbent pore. • Conversion of siloxane was caused by adsorption of noncarbon adsorbents. - Abstract: Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane.

  13. A theoretical and experimental study on the P-adsorption capacity of Phoslock™

    NASA Astrophysics Data System (ADS)

    Zamparas, Miltiadis; Gavriil, Gavriil; Coutelieris, Frank A.; Zacharias, Ierotheos

    2015-04-01

    The main objective of this study is to investigate the adsorption process from both experimental and modeling point of view of phosphate onto Phoslock™, an increasingly used worldwide restoration tool to control phosphorus from natural water ecosystems. Bench-scale batch experiments were performed to examine its efficiency as a phosphate adsorbent and detailed simulations were carried out, allowing for a deep insight of the removal process. The adsorption efficiency calculated by the simulations is 87.41%, being in excellent agreement with that experimentally measured (approx. 87%). However, it is important to notice the discrepancy between experimental measures and simulation estimates. Although the agreement is perfect for T = 25 °C, it becomes more and more poor as temperature decreases, approaching approx. 10% difference for the low temperature of 10 °C. This inconsistency between experiments and model can be attributed to the internal inefficiencies of unit cell approach, which in particular overestimates the adsorption efficiency.

  14. Visualization of the exothermal VOC adsorption in a fixed-bed activated carbon adsorber.

    PubMed

    Le Cloirec, P; Pré, P; Delage, F; Giraudet, S

    2012-01-01

    Activated carbon fixed beds are classically used to remove volatile organic compounds (VOCs) present in gaseous emissions. In such use, an increase of local temperature due to exothermal adsorption has been reported; some accidental fires in the carbon bed due to the removal of high concentrations of ketones have been published. In this work, removal of VOCs was performed in a laboratory-scale pilot unit. In order to visualize the increase in local temperature, the adsorption front was tracked with a flame ionization detector and the thermal wave was simultaneously visualized with an infrared camera. In extreme conditions, fire in the adsorber and the combustion of activated carbon was achieved during ketone adsorption. Data have been extracted from these experiments, including local temperature, front velocity and carbon bed combustion conditions.

  15. Nitrogen-doped porous aromatic frameworks for enhanced CO2 adsorption

    DOE PAGES

    Fu, Jia; Wu, Jianzhong; Custelcean, Radu; Jiang, De-en

    2014-10-07

    Recently synthesized porous aromatic frameworks (PAFs) exhibit extremely high surface areas and exceptional thermal and hydrothermal stabilities. Using computer-aided design, we propose new PAFs, designated as NPAFs, by introducing nitrogen-containing groups to the biphenyl unit and predict their CO2 adsorption capacities with grand canonical Monte Carlo (GCMC) simulations. Among various NPAFs considered, one with imidazole groups shows the highest adsorption capacity for CO2 (11.5wt % at 1bar and 298K) , in comparison with 5wt % for the parent PAF (PAF- 1) at the same condition. At higher pressures (around 10bar) ,though, another NPAF with pyridinic N groups performs much bettermore » than the rest due to its greater pore volume in addition to the N functionality. This research suggests that adding N functionality to the organic linkers is a promising way to increase CO2 adsorption capacity of PAFs at ambient condition.« less

  16. Nitrogen-doped porous aromatic frameworks for enhanced CO2 adsorption

    SciTech Connect

    Fu, Jia; Wu, Jianzhong; Custelcean, Radu; Jiang, De-en

    2014-10-07

    Recently synthesized porous aromatic frameworks (PAFs) exhibit extremely high surface areas and exceptional thermal and hydrothermal stabilities. Using computer-aided design, we propose new PAFs, designated as NPAFs, by introducing nitrogen-containing groups to the biphenyl unit and predict their CO2 adsorption capacities with grand canonical Monte Carlo (GCMC) simulations. Among various NPAFs considered, one with imidazole groups shows the highest adsorption capacity for CO2 (11.5wt % at 1bar and 298K) , in comparison with 5wt % for the parent PAF (PAF- 1) at the same condition. At higher pressures (around 10bar) ,though, another NPAF with pyridinic N groups performs much better than the rest due to its greater pore volume in addition to the N functionality. This research suggests that adding N functionality to the organic linkers is a promising way to increase CO2 adsorption capacity of PAFs at ambient condition.

  17. EDTA-Cross-Linked β-Cyclodextrin: An Environmentally Friendly Bifunctional Adsorbent for Simultaneous Adsorption of Metals and Cationic Dyes.

    PubMed

    Zhao, Feiping; Repo, Eveliina; Yin, Dulin; Meng, Yong; Jafari, Shila; Sillanpää, Mika

    2015-09-01

    The discharge of metals and dyes poses a serious threat to public health and the environment. What is worse, these two hazardous pollutants are often found to coexist in industrial wastewaters, making the treatment more challenging. Herein, we report an EDTA-cross-linked β-cyclodextrin (EDTA-β-CD) bifunctional adsorbent, which was fabricated by an easy and green approach through the polycondensation reaction of β-cyclodextrin with EDTA as a cross-linker, for simultaneous adsorption of metals and dyes. In this setting, cyclodextrin cavities are expected to capture dye molecules through the formation of inclusion complexes and EDTA units as the adsorption sites for metals. The adsorbent was characterized by FT-IR, elemental analysis, SEM, EDX, ζ-potential, and TGA. In a monocomponent system, the adsorption behaviors showed a monolayer adsorption capacity of 1.241 and 1.106 mmol g(-1) for Cu(II) and Cd(II), respectively, and a heterogeneous adsorption capacity of 0.262, 0.169, and 0.280 mmol g(-1) for Methylene Blue, Safranin O, and Crystal Violet, respectively. Interestingly, the Cu(II)-dye binary experiments showed adsorption enhancement of Cu(II), but no significant effect on dyes. The simultaneous adsorption mechanism was further confirmed by FT-IR, thermodynamic study, and elemental mapping. Overall, its facile and green fabrication, efficient sorption performance, and excellent reusability indicate that EDTA-β-CD has potential for practical applications in integrative and efficient treatment of coexistenting toxic pollutants.

  18. Adsorption Isotherms and Surface Reaction Kinetics

    ERIC Educational Resources Information Center

    Lobo, L. S.; Bernardo, C. A.

    1974-01-01

    Explains an error that occurs in calculating the conditions for a maximum value of a rate expression for a bimolecular reaction. The rate expression is derived using the Langmuir adsorption isotherm to relate gas pressures and corresponding surface coverages. (GS)

  19. Adsorption of nisin and pediocin on nanoclays.

    PubMed

    Meira, Stela Maris Meister; Jardim, Arthur Izé; Brandelli, Adriano

    2015-12-01

    Three different nanoclays (bentonite, octadecylamine-modified montmorillonite and halloysite) were studied as potential carriers for the antimicrobial peptides nisin and pediocin. Adsorption occurred from peptide solutions in contact with nanoclays at room temperature. Higher adsorption of nisin and pediocin was obtained on bentonite. The antimicrobial activity of the resultant bacteriocin-nanoclay systems was analyzed using skimmed milk agar as food simulant and the largest inhibition zones were observed against Gram-positive bacteria for halloysite samples. Bacteriocins were intercalated into the interlayer space of montmorillonites as deduced from the increase of the basal spacing measured by X-ray diffraction (XRD) assay. Infrared spectroscopy suggested non-electrostatic interactions, such as hydrogen bonding between siloxane groups from clays and peptide molecules. Transmission electron microscopy did not show any alteration in morphologies after adsorption of antimicrobial peptides on bentonite and halloysite. These results indicate that nanoclays, especially halloysite, are suitable nanocarriers for nisin and pediocin adsorption.

  20. Adsorption of nisin and pediocin on nanoclays.

    PubMed

    Meira, Stela Maris Meister; Jardim, Arthur Izé; Brandelli, Adriano

    2015-12-01

    Three different nanoclays (bentonite, octadecylamine-modified montmorillonite and halloysite) were studied as potential carriers for the antimicrobial peptides nisin and pediocin. Adsorption occurred from peptide solutions in contact with nanoclays at room temperature. Higher adsorption of nisin and pediocin was obtained on bentonite. The antimicrobial activity of the resultant bacteriocin-nanoclay systems was analyzed using skimmed milk agar as food simulant and the largest inhibition zones were observed against Gram-positive bacteria for halloysite samples. Bacteriocins were intercalated into the interlayer space of montmorillonites as deduced from the increase of the basal spacing measured by X-ray diffraction (XRD) assay. Infrared spectroscopy suggested non-electrostatic interactions, such as hydrogen bonding between siloxane groups from clays and peptide molecules. Transmission electron microscopy did not show any alteration in morphologies after adsorption of antimicrobial peptides on bentonite and halloysite. These results indicate that nanoclays, especially halloysite, are suitable nanocarriers for nisin and pediocin adsorption. PMID:26041178

  1. Argon adsorption and the lunar atmosphere

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    The results of Ar adsorption experiments on a terrestrial labradorite and lunar rock 15415 crushed in vacuo are reported. The experiments were designed to test lunar atmosphere simulation models for the behavior of Ar on the lunar surface, as determined from the Apollo 17 mass spectrometer results. These models (Hodges, 1980, 1982) used a single adsorption potential to characterize the surfaces of lunar soil grains, with the result that high (6-7 kcal/mol) heats of adsorption were inferred. The present experimental results show that very high adsorption potentials are indeed associated with fresh mineral surfaces, but that these energetic surfaces occupy only small fractions of the total surface area. Nonetheless, these small fractions of surface, if they can be maintained in the lunar regolith in steady-state condition, could be sufficient to account for the Apollo 17 mass spectrometer observations.

  2. H2O Adsorption Kinetics on Smectites

    NASA Technical Reports Server (NTRS)

    Zent, Aaron P.; Howard, J.; Quinn, R. C.

    2000-01-01

    The adsorptive equilibration of H2O with montomorillonite has been measured. At low temperatures and pressures equilibration can require many hours, effectively preventing smectites at the martian surface from responding to diurnal pressure and temperature variations.

  3. Fluorocarbon Adsorption in Hierarchical Porous Frameworks

    SciTech Connect

    Motkuri, Radha K.; Annapureddy, Harsha V.; Vijayakumar, M.; Schaef, Herbert T.; Martin, P F.; McGrail, B. Peter; Dang, Liem X.; Krishna, Rajamani; Thallapally, Praveen K.

    2014-07-09

    The adsorption behavior of a series of fluorocarbon derivatives was examined on a set of microporous metal organic framework (MOF) sorbents and another set of hierarchical mesoporous MOFs. The microporous M-DOBDC (M = Ni, Co) showed a saturation uptake capacity for R12 of over 4 mmol/g at a very low relative saturation pressure (P/Po) of 0.02. In contrast, the mesoporous MOF MIL-101 showed an exceptionally high uptake capacity reaching over 14 mmol/g at P/Po of 0.4. Adsorption affinity in terms of mass loading and isosteric heats of adsorption were found to generally correlate with the polarizability of the refrigerant with R12 > R22 > R13 > R14 > methane. These results suggest the possibility of exploiting MOFs for separation of azeotropic mixtures of fluorocarbons and use in eco-friendly fluorocarbon-based adsorption cooling and refrigeration applications.

  4. Krypton based adsorption type cryogenic refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor); Schember, Helene R. (Inventor)

    1989-01-01

    Krypton and a monolithic porous carbon such as Saran carbon are used respectively as the sorbate and sorbent of an adsorption type refrigerator to improve refrigeration efficiency and operational longevity.

  5. Evaluation of the potassium adsorption capacity of a potassium adsorption filter during rapid blood transfusion.

    PubMed

    Matsuura, H; Akatsuka, Y; Muramatsu, C; Isogai, S; Sugiura, Y; Arakawa, S; Murayama, M; Kurahashi, M; Takasuga, H; Oshige, T; Yuba, T; Mizuta, S; Emi, N

    2015-05-01

    The concentration of extracellular potassium in red blood cell concentrates (RCCs) increases during storage, leading to risk of hyperkalemia. A potassium adsorption filter (PAF) can eliminate the potassium at normal blood transfusion. This study aimed to investigate the potassium adsorption capacity of a PAF during rapid blood transfusion. We tested several different potassium concentrations under a rapid transfusion condition using a pressure bag. The adsorption rates of the 70-mEq/l model were 76·8%. The PAF showed good potassium adsorption capacity, suggesting that this filter may provide a convenient method to prevent hyperkalemia during rapid blood transfusion.

  6. Gas adsorption capacity of wood pellets

    DOE PAGES

    Yazdanpanah, F.; Sokhansanj, Shahabaddine; Lim, C. Jim; Lau, A.; Bi, X. T.

    2016-02-03

    In this paper, temperature-programmed desorption (TPD) analysis was used to measure and analyze the adsorption of off-gases and oxygen by wood pellets during storage. Such information on how these gases interact with the material helps in the understanding of the purging/stripping behavior of off-gases to develop effective ventilation strategies for wood pellets. Steam-exploded pellets showed the lowest carbon dioxide (CO2) uptake compared to the regular and torrefied pellets. The high CO2 adsorption capacity of the torrefied pellets could be attributed to their porous structure and therefore greater available surface area. Quantifying the uptake of carbon monoxide by pellets was challengingmore » due to chemical adsorption, which formed a strong bond between the material and carbon monoxide. The estimated energy of desorption for CO (97.8 kJ/mol) was very high relative to that for CO2 (7.24 kJ/mol), demonstrating the mechanism of chemical adsorption and physical adsorption for CO and CO2, respectively. As for oxygen, the strong bonds that formed between the material and oxygen verified the existence of chemical adsorption and formation of an intermediate material.« less

  7. Defluoridation of drinking water using adsorption processes.

    PubMed

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

    2013-03-15

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

  8. 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.

  9. Evaluation and Improvement of Real-Time PCR Assays Targeting lytA, ply, and psaA Genes for Detection of Pneumococcal DNA▿

    PubMed Central

    Carvalho, Maria da Gloria S.; Tondella, Maria Lucia; McCaustland, Karen; Weidlich, Luciana; McGee, Lesley; Mayer, Leonard W.; Steigerwalt, Arnold; Whaley, Melissa; Facklam, Richard R.; Fields, Barry; Carlone, George; Ades, Edwin W.; Dagan, Ron; Sampson, Jacquelyn S.

    2007-01-01

    The accurate diagnosis of pneumococcal disease has frequently been hampered not only by the difficulties in obtaining isolates of the organism from patient specimens but also by the misidentification of pneumococcus-like viridans group streptococci (P-LVS) as Streptococcus pneumoniae. This is especially critical when the specimen comes from the respiratory tract. In this study, three novel real-time PCR assays designed for the detection of specific sequence regions of the lytA, ply, and psaA genes were developed (lytA-CDC, ply-CDC, and psaA, respectively). These assays showed high sensitivity (<10 copies for lytA-CDC and ply-CDC and an approximately twofold less sensitivity for psaA). Two additional real-time PCR assays for lytA and ply described previously for pneumococcal DNA detection were also evaluated. A panel of isolates consisting of 67 S. pneumoniae isolates (44 different serotypes and 3 nonencapsulated S. pneumoniae isolates from conjunctivitis outbreaks) and 104 nonpneumococcal isolates was used. The 67 S. pneumoniae isolates were reactive in all five assays. The new real-time detection assays targeting the lytA and psaA genes were the most specific for the detection of isolates confirmed to be S. pneumoniae, with lytA-CDC showing the greatest specificity. Both ply PCRs were positive for all isolates of S. pseudopneumoniae, along with 13 other isolates of other P-LVS isolates confirmed to be non-S. pneumoniae by DNA-DNA reassociation. Thus, the use of the ply gene for the detection of pneumococci can lead to false-positive reactions in the presence of P-LVS. The five assays were applied to 15 culture-positive cerebrospinal fluid specimens with 100% sensitivity; and serum and ear fluid specimens were also evaluated. Both the lytA-CDC and psaA assays, particularly the lytA-CDC assay, have improved specificities compared with those of currently available assays and should therefore be considered the assays of choice for the detection of pneumococcal DNA

  10. Evaluation and improvement of real-time PCR assays targeting lytA, ply, and psaA genes for detection of pneumococcal DNA.

    PubMed

    Carvalho, Maria da Gloria S; Tondella, Maria Lucia; McCaustland, Karen; Weidlich, Luciana; McGee, Lesley; Mayer, Leonard W; Steigerwalt, Arnold; Whaley, Melissa; Facklam, Richard R; Fields, Barry; Carlone, George; Ades, Edwin W; Dagan, Ron; Sampson, Jacquelyn S

    2007-08-01

    The accurate diagnosis of pneumococcal disease has frequently been hampered not only by the difficulties in obtaining isolates of the organism from patient specimens but also by the misidentification of pneumococcus-like viridans group streptococci (P-LVS) as Streptococcus pneumoniae. This is especially critical when the specimen comes from the respiratory tract. In this study, three novel real-time PCR assays designed for the detection of specific sequence regions of the lytA, ply, and psaA genes were developed (lytA-CDC, ply-CDC, and psaA, respectively). These assays showed high sensitivity (<10 copies for lytA-CDC and ply-CDC and an approximately twofold less sensitivity for psaA). Two additional real-time PCR assays for lytA and ply described previously for pneumococcal DNA detection were also evaluated. A panel of isolates consisting of 67 S. pneumoniae isolates (44 different serotypes and 3 nonencapsulated S. pneumoniae isolates from conjunctivitis outbreaks) and 104 nonpneumococcal isolates was used. The 67 S. pneumoniae isolates were reactive in all five assays. The new real-time detection assays targeting the lytA and psaA genes were the most specific for the detection of isolates confirmed to be S. pneumoniae, with lytA-CDC showing the greatest specificity. Both ply PCRs were positive for all isolates of S. pseudopneumoniae, along with 13 other isolates of other P-LVS isolates confirmed to be non-S. pneumoniae by DNA-DNA reassociation. Thus, the use of the ply gene for the detection of pneumococci can lead to false-positive reactions in the presence of P-LVS. The five assays were applied to 15 culture-positive cerebrospinal fluid specimens with 100% sensitivity; and serum and ear fluid specimens were also evaluated. Both the lytA-CDC and psaA assays, particularly the lytA-CDC assay, have improved specificities compared with those of currently available assays and should therefore be considered the assays of choice for the detection of pneumococcal DNA

  11. The special features of protein adsorption isotherms on silica adsorbents

    NASA Astrophysics Data System (ADS)

    Chukhrai, E. S.; Atyaksheva, L. F.; Pilipenko, O. S.

    2011-05-01

    The adsorption isotherms of hemoglobin, peroxidase, and β-galactosidase on silochrome and mesoporous and biporous silicas were comparatively studied. Adsorption developed in two stages, including fast "reversible" protein adsorption (equilibrium was reached in t ≤ 1-2 h) and a "slow stage" of irreversible binding in t ≫ 24 h (multipoint adsorption). The corresponding equilibrium constants were determined. The mechanism of unlimited linear association of peroxidase in the adsorption layer on the surface of silochrome was established.

  12. Additive surface complexation modeling of uranium(VI) adsorption onto quartz-sand dominated sediments.

    PubMed

    Dong, Wenming; Wan, Jiamin

    2014-06-17

    Many aquifers contaminated by U(VI)-containing acidic plumes are composed predominantly of quartz-sand sediments. The F-Area of the Savannah River Site (SRS) in South Carolina (USA) is an example. To predict U(VI) mobility and natural attenuation, we conducted U(VI) adsorption experiments using the F-Area plume sediments and reference quartz, goethite, and kaolinite. The sediments are composed of ∼96% quartz-sand and 3-4% fine fractions of kaolinite and goethite. We developed a new humic acid adsorption method for determining the relative surface area abundances of goethite and kaolinite in the fine fractions. This method is expected to be applicable to many other binary mineral pairs, and allows successful application of the component additivity (CA) approach based surface complexation modeling (SCM) at the SRS F-Area and other similar aquifers. Our experimental results indicate that quartz has stronger U(VI) adsorption ability per unit surface area than goethite and kaolinite at pH ≤ 4.0. Our modeling results indicate that the binary (goethite/kaolinite) CA-SCM under-predicts U(VI) adsorption to the quartz-sand dominated sediments at pH ≤ 4.0. The new ternary (quartz/goethite/kaolinite) CA-SCM provides excellent predictions. The contributions of quartz-sand, kaolinite, and goethite to U(VI) adsorption and the potential influences of dissolved Al, Si, and Fe are also discussed.

  13. Adsorption of ethanol onto activated carbon: Modeling and consequent interpretations based on statistical physics treatment

    NASA Astrophysics Data System (ADS)

    Bouzid, Mohamed; Sellaoui, Lotfi; Khalfaoui, Mohamed; Belmabrouk, Hafedh; Lamine, Abdelmottaleb Ben

    2016-02-01

    In this work, we studied the adsorption of ethanol on three types of activated carbon, namely parent Maxsorb III and two chemically modified activated carbons (H2-Maxsorb III and KOH-H2-Maxsorb III). This investigation has been conducted on the basis of the grand canonical formalism in statistical physics and on simplified assumptions. This led to three parameter equations describing the adsorption of ethanol onto the three types of activated carbon. There was a good correlation between experimental data and results obtained by the new proposed equation. The parameters characterizing the adsorption isotherm were the number of adsorbed molecules (s) per site n, the density of the receptor sites per unit mass of the adsorbent Nm, and the energetic parameter p1/2. They were estimated for the studied systems by a non linear least square regression. The results show that the ethanol molecules were adsorbed in perpendicular (or non parallel) position to the adsorbent surface. The magnitude of the calculated adsorption energies reveals that ethanol is physisorbed onto activated carbon. Both van der Waals and hydrogen interactions were involved in the adsorption process. The calculated values of the specific surface AS, proved that the three types of activated carbon have a highly microporous surface.

  14. Asphaltene Adsorption onto Self-Assembled Monolayers of Alkyltrichlorosilanes of Varying Chain Length

    SciTech Connect

    Turgman-Cohen, S.; Fischer, D; Kilpatrick, P; Genzer, J

    2009-01-01

    The adsorption of asphaltenes onto flat silica surfaces modified with self-assembled monolayers (SAMs) of alkyltrichlorosilanes of varying thickness due to a variable number of carbon atoms (N{sub C}) has been studied by means of contact angle measurements, spectroscopic ellipsometry, and near-edge X-ray absorption fine structure spectroscopy. The extent of asphaltene adsorption was found to depend primarily on the ability of the SAM layer to shield the underlying silicon substrate from interacting with the asphaltenes present in solution. Specifically, asphaltene adsorption decreased with an increase in NC and/or an increase in SAM grafting density, {sigma}{sub SAM}, (i.e., number of SAM molecules per unit area). The effect of the solvent quality on the extent of asphaltene adsorption was gauged by adsorbing asphaltenes from toluene, 1-methylnaphthalene, tetralin, decalin, and toluene-heptanes mixtures. The extent of asphaltene adsorption was found to increase proportionally with a decrease in the Hildebrand solubility parameter of the solvent.

  15. Concerning Units.

    ERIC Educational Resources Information Center

    Wadlinger, Robert L.

    1983-01-01

    SI units come in two distinct types: fundamental (kilogram, meter) and descriptive (atom, molecule). Proper/improper uses of atom/molecule from historical cases are presented followed by a re-introduction of a light "wave (cycle)" unit and the clearly defined photon model which is deduced. Also examines omission of the fundamental unit "radon."…

  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. 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

  18. Speciation of Sb(III) and Sb(V) in meglumine antimoniate pharmaceutical formulations by PSA using carbon nanotube electrode.

    PubMed

    Santos, Vivian Silva; Santos, Wilney de Jesus Rodrigues; Kubota, Lauro Tatsuo; Tarley, César Ricardo Teixeira

    2009-09-01

    A new and simple electroanalytical method for speciation of Sb(III) and Sb(V) in pharmaceutical formulation by potentiometric stripping analysis (PSA) using a multiwall carbon nanotube paste electrode was developed. All instrumental and chemical parameters influencing the performance of the method were carefully assessed and optimized. Trivalent antimony was determined in acid medium (pH 3.6) under the optimized condition (deposition potential of -0.7 V, deposition time of 180 s, ionic strength of 0.3M and oxidant mercury concentration of 10 mg l(-1)). Total antimony was determined after quantitative reduction of Sb(V) with l-cysteine (1.5%, w/v) and its concentration was calculated from difference between the total antimony and Sb(III). The developed method provided two distinct linear calibration one ranging from 10 up to 50 microg l(-1) and other from 100 up to 800 microg l(-1) with respective correlation coefficient of 0.9978 and 0.9993, presenting a detection limit of 6.2 microg l(-1). Repeatability for the six independent samples expressed in terms of relative standard deviation was found to be 3.01 and 1.39% for 40.0 and 300.0 microg l(-1) antimony concentration, respectively. Results on the effect of foreign substances [Al(III), Mg(II), Fe(III), Cd(II), Zn(II) and meglumine] on analytical signal of antimony showed no interference even using high content of foreign ions in the analyte:interferent ratio up to 1:100. The proposed method was successfully applied for the speciation of Sb(III) and Sb(V) in pharmaceutical formulation and the accuracy was assessed from addition and recovery tests as well as comparing with graphite furnace atomic absorption spectrometry (GF AAS) technique used as reference analytical method.

  19. Adsorption of poly(ethylene glycol)-modified ribonuclease A to a poly(lactide-co-glycolide) surface.

    PubMed

    Daly, Susan M; Przybycien, Todd M; Tilton, Robert D

    2005-06-30

    Protein adsorption is a source of variability in the release profiles of therapeutic proteins from biodegradable microspheres. We employ optical reflectometry and total internal reflection fluorescence to explore the extent and kinetics of ribonuclease A (RNase A) adsorption to spin-cast films of poly(lactide-co-glycolide) (PLG) and, in particular, to determine how covalent grafting of polyethylene glycol (PEG) to RNase A affects adsorption. Adsorption kinetics on PLG surfaces are surface-limited for RNase A but transport-limited for unconjugated PEG homopolymers and for PEG-modified RNase A, indicating that PEG anchors the conjugates to the surface during the transport-limited regime. PEG modification of RNase A decreases the total number of adsorbed molecules per unit area but increases the areal surface coverage because the grafted PEG chains exclude additional surface area. Total internal reflection fluorescence-based exchange measurements show that there is no exchange between adsorbed and solution-phase protein molecules. This indicates an unusually tenacious adsorption. Streaming current measurements indicate that the zeta potential of the PLG surface becomes increasingly negative as the film is exposed to water for several weeks, as expected. Aging of the PLG surface results in increased adsorption of unmodified RNase A but decreased adsorption of unconjugated PEG homopolymers and of PEG-RNase A conjugates, relative to the extent of adsorption on freshly prepared PLG surfaces. Adsorption results correlate well with an increase in the rate, total extent and preservation of bioactivity of RNase A released from PLG microspheres for the PEG-modified version of RNase A.

  20. A Novel Parametric Analysis of a Conventional Silica-Gel Water Adsorption Chiller

    NASA Astrophysics Data System (ADS)

    Alam, K. C. A.; Saha, B. B.; Akisawa, Atsushi; Kashiwagi, Takao

    A conventional adsorption chiller with silica gel as adsorbent and water as adsorbate has been analyzed numerically. In the present study, a non-dimensional simulation model has been presented and a set of non-dimensional parameters for conventional adsorption chiller has been derived. The results obtained by simulation method are confirmed by the experimental results. Simulation results show that switching speed is most influential parameter and there is an optimum switching speed for cooling capacity and COP. Results also show that system performance (cooling capacity and COP) is strongly affected by the number of transfer unit of adsorber/desorber, NTUa due to severe sensible heating/cooling requirements. The model is somewhat sensitive to the number of transfer unit of evaporator, NTUe. The number of transfer unit of condenser, NTUc is the least sensitive parameter. Finally, an investigation is made parametrically to obtain the optimum value of switching speed and the number of transfer unit, NTU of different component. The present model can be employed to analyze and to optimize the adsorption cooling/heat pump system.

  1. Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test.

    PubMed

    Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee; Park, Jin-Kyu; Lee, Namhoon

    2013-10-01

    Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane.

  2. Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test.

    PubMed

    Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee; Park, Jin-Kyu; Lee, Namhoon

    2013-10-01

    Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane. PMID:23684695

  3. Modeling adsorption: Investigating adsorbate and adsorbent properties

    NASA Astrophysics Data System (ADS)

    Webster, Charles Edwin

    1999-12-01

    Surface catalyzed reactions play a major role in current chemical production technology. Currently, 90% of all chemicals are produced by heterogeneously catalyzed reactions. Most of these catalyzed reactions involve adsorption, concentrating the substrate(s) (the adsorbate) on the surface of the solid (the adsorbent). Pore volumes, accessible surface areas, and the thermodynamics of adsorption are essential in the understanding of solid surface characteristics fundamental to catalyst and adsorbent screening and selection. Molecular properties such as molecular volumes and projected molecular areas are needed in order to convert moles adsorbed to surface volumes and areas. Generally, these molecular properties have been estimated from bulk properties, but many assumptions are required. As a result, different literature values are employed for these essential molecular properties. Calculated molar volumes and excluded molecular areas are determined and tabulated for a variety of molecules. Molecular dimensions of molecules are important in the understanding of molecular exclusion as well as size and shape selectivity, diffusion, and adsorbent selection. Molecular dimensions can also be used in the determination of the effective catalytic pore size of a catalyst. Adsorption isotherms, on zeolites, (crystalline mineral oxides) and amorphous solids, can be analyzed with the Multiple Equilibrium Analysis (MEA) description of adsorption. The MEA produces equilibrium constants (Ki), capacities (ni), and thermodynamic parameters (enthalpies, ΔHi, and entropies, ΔSi) of adsorption for each process. Pore volumes and accessible surface areas are calculated from the process capacities. Adsorption isotherms can also be predicted for existing and new adsorbate-adsorbent systems with the MEA. The results show that MEA has the potential of becoming a standard characterization method for microporous solids that will lead to an increased understanding of their behavior in gas

  4. Adding adsorption to a geothermal simulator

    SciTech Connect

    Holt, R.; Pingol, A.

    1992-01-01

    Physical adsorption of steam has increasingly become recognized as an important storage mechanism in vapor dominated geothermal reservoirs. A method has been developed which allows the effects of adsorption to be modeled using TETRAD, a commercially available geothermal simulator. The method consists of replacing the standard steam table with a new steam table which has been derived to include adsorptive effects. The TETRAD simulator, when run with the pseudo steam table, approximately matches the pressure, production, and saturation behavior of a desorbing geothermal system. Adsorption can be described as the existence of an immobile layer of liquid on the surfaces within a porous medium. The presence of an adsorbed liquid water layer in rocks has been shown experimentally to cause the vapor pressure of steam to be lower than its flat surface vapor pressure for a particular The pseudo steam table accounts for this vapor pressure lowering effect. A test run was made with TETRAD using the pseudo steam table and a low porosity, low permeability reservoir matrix. This test run was compared to an equivalent run made with Stanford Geothermal Program's simulator, ADSORB. The program ADSORB is a one dimensional simulator which has adsorption effects built into its difference equations. The comparison of these runs shows that the pseudo steam table allows TETRAD to match the behavior of the ADSORB simulator. Injection was not investigated in this study. A convenient method of modeling adsorption with TETRAD is to use standard steam tables while allowing for the vapor pressure lowering effect of adsorption. This will require modifications of the equations in the code that describe the partial pressure of the steam phase.

  5. Impact of the interaction with the positive charge in adsorption of benzene and other organic compounds from aqueous solutions on carbons

    NASA Astrophysics Data System (ADS)

    Terzyk, Artur P.; Ćwiertnia, Magdalena S.; Wiśniewski, Marek; Gauden, Piotr A.; Rychlicki, Gerhard; Szymański, Grzegorz S.

    2007-02-01

    We present the results of benzene adsorption at the acidic pH level determined on the series of chemically modified activated carbons and at three temperatures. The influence of carbon surface chemical composition on benzene adsorption is discussed. It is shown that the decrease in the pH level from 7 up to 1.5 increases benzene adsorption and the only exception is carbon modified with gaseous ammonia. Basing on the results of current work and those published previously (for phenol, paracetamol, acetanilide and aniline) and using the results of quantum chemistry calculations (DFT, Gaussian 98) we show, that the value of the energy of interaction with unit positive charge is crucial during the analysis of the influence of pH level on adsorption. Obtained results allow to predict the changes in adsorption of aromatics on carbons with the decrease in the pH level.

  6. Method and apparatus for thermal swing adsorption and thermally-enhanced pressure swing adsorption

    DOEpatents

    Wegeng, Robert S.; Rassat, Scot D.; TeGrotenhuis, Ward E.; Drost, Kevin; Vishwanathan, Vilayanur V.

    2004-06-08

    The present invention provides compact adsorption systems that are capable of rapid temperature swings and rapid cycling. Novel methods of thermal swing adsorption and thermally-enhanced pressure swing adsorption are also described. In some aspects of the invention, a gas is passed through the adsorbent thus allowing heat exchangers to be very close to all portions of the adsorbent and utilize less space. In another aspect, the adsorption media is selectively heated, thus reducing energy costs. Methods and systems for gas adsorption/desorption having improved energy efficiency with capability of short cycle times are also described. In another aspect, the apparatus or methods utilize heat exchange channels of varying lengths that have volumes controlled to provide equal heat fluxes. Methods of fuel cell startup are also described. Advantages of the invention include the ability to use (typically) 30-100 times less adsorbent compared to conventional systems.

  7. Method for thermal swing adsorption and thermally-enhanced pressure swing adsorption

    DOEpatents

    Wegeng, Robert S.; Rassat, Scot D.; Stenkamp, Victoria S.; TeGrotenhuis, Ward E.; Matson, Dean W.; Drost, M. Kevin; Viswanathan, Vilayanur V.

    2003-10-07

    The present invention provides compact adsorption systems that are capable of rapid temperature swings and rapid cycling. Novel methods of thermal swing adsorption and thermally-enhanced pressure swing adsorption are also described. In some aspects of the invention, a gas is passed through the adsorbent thus allowing heat exchangers to be very close to all portions of the adsorbent and utilize less space. In another aspect, the adsorption media is selectively heated, thus reducing energy costs. Methods and systems for gas adsorption/desorption having improved energy efficiency with capability of short cycle times are also described. Advantages of the invention include the ability to use (typically) 30-100 times less adsorbent compared to conventional systems.

  8. Apparatus for thermal swing adsorption and thermally-enhanced pressure swing adsorption

    DOEpatents

    Wegeng, Robert S.; Rassat, Scot D.; Stenkamp, Victoria S.; TeGrotenhuis, Ward E.; Matson, Dean W.; Drost, M. Kevin; Viswanathan, Vilayanur V.

    2005-12-13

    The present invention provides compact adsorption systems that are capable of rapid temperature swings and rapid cycling. Novel methods of thermal swing adsorption and thermally-enhanced pressure swing adsorption are also described. In some aspects of the invention, a gas is passed through the adsorbent thus allowing heat exchangers to be very close to all portions of the adsorbent and utilize less space. In another aspect, the adsorption media is selectively heated, thus reducing energy costs. Methods and systems for gas adsorption/desorption having improved energy efficiency with capability of short cycle times are also described. Advantages of the invention include the ability to use (typically) 30-100 times less adsorbent compared to conventional systems.

  9. Adsorption of phenolic compound by aged-refuse.

    PubMed

    Xiaoli, Chai; Youcai, Zhao

    2006-09-01

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

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

    SciTech Connect

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

    2007-01-01

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

  11. Neptunium(V) adsorption to calcite

    NASA Astrophysics Data System (ADS)

    Heberling, Frank; Brendebach, Boris; Bosbach, Dirk

    2008-12-01

    The migration behavior of the actinyl ions U(VI)O 22+, Np(V)O 2+ and Pu(V,VI)O 2(+,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 NpO 2+ adsorption onto calcite is studied in batch type experiments over a wide range of pH (6.0-9.4) and concentration (0.4 μM-40 μM) conditions. pH is adjusted by variation of CO 2 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 Å for the adsorbed and 1.82 ± 0.01 Å for the solution species. The equatorial environment of the neptunyl in solution shows about 5 oxygen neighbours at 2.45 ± 0.02 Å. For adsorbed neptunyl there are also about 5 oxygen neighbours at 2.46 ± 0.01 Å. 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 Å and 3 to 6 oxygen backscatterers (O-eq2) at 3.31 ± 0.02 Å. 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.

  12. Confirmation of a Low {alpha}/{beta} Ratio for Prostate Cancer Treated by External Beam Radiation Therapy Alone Using a Post-Treatment Repeated-Measures Model for PSA Dynamics

    SciTech Connect

    Proust-Lima, Cecile; Taylor, Jeremy M.G.; Secher, Solene; Sandler, Howard; Kestin, Larry; Pickles, Tom; Bae, Kyoungwha; Allison, Roger; Williams, Scott

    2011-01-01

    Purpose: To estimate the {alpha}/{beta} ratio of prostate cancer treated with external beam radiation only by use of a model of long-term prostate-specific antigen (PSA) dynamics. Methods and Materials: Repeated measures of PSA from 5,093 patients from 6 institutions treated for localized prostate cancer by external beam radiation therapy (EBRT) without planned androgen deprivation were analyzed. A biphasic linear mixed model described the post-treatment evolution of PSA, rather than a conventional model of time to biochemical recurrence. The model was adjusted for standard prognostic factors (T stage, initial PSA level, and Gleason score) and cohort-specific effects. The radiation dose fractionation effect was estimated from the long-term rate of rise of PSA level. Results: Adjusted for other factors, total dose of EBRT and sum of squared doses per fraction were associated with long-term rate of change of PSA level (p = 0.0017 and p = 0.0003, respectively), an increase of each being associated with a lower rate of rise. The {alpha}/{beta} ratio was estimated at 1.55 Gy (95% confidence band, 0.46-4.52 Gy). This estimate was robust to adjustment of the linear mixed model. Conclusions: By analysis of a large EBRT-only cohort along with a method that uses all the repeated measures of PSA after the end of treatment, a low and precise {alpha}/{beta} was estimated. These data support the use of hypofractionation at fractional doses up to 2.8 Gy but cannot presently be assumed to accurately represent higher doses per fraction.

  13. Failure to Achieve a PSA Level {<=}1 ng/mL After Neoadjuvant LHRHA Therapy Predicts for Lower Biochemical Control Rate and Overall Survival in Localized Prostate Cancer Treated With Radiotherapy

    SciTech Connect

    Mitchell, Darren M. McAleese, Jonathan; Park, Richard M.; Stewart, David P.; Stranex, Stephen; Eakin, Ruth L.; Houston, Russell F.; O'Sullivan, Joe M.

    2007-12-01

    Purpose: To investigate whether failure to suppress the prostate-specific antigen (PSA) level to {<=}1 ng/mL after {>=}2 months of neoadjuvant luteinizing hormone-releasing hormone agonist therapy in patients scheduled to undergo external beam radiotherapy for localized prostate carcinoma is associated with reduced biochemical failure-free survival. Methods and Materials: A retrospective case note review of consecutive patients with intermediate- or high-risk localized prostate cancer treated between January 2001 and December 2002 with neoadjuvant hormonal deprivation therapy, followed by concurrent hormonal therapy and radiotherapy was performed. Patient data were divided for analysis according to whether the PSA level in Week 1 of radiotherapy was {<=}1.0 ng/mL. Biochemical failure was determined using the American Society for Therapeutic Radiology and Oncology (Phoenix) definition. Results: A total of 119 patients were identified. The PSA level after neoadjuvant hormonal deprivation therapy was {<=}1 ng/mL in 67 patients and >1 ng/mL in 52. At a median follow-up of 49 months, the 4-year actuarial biochemical failure-free survival rate was 84% vs. 60% (p = 0.0016) in favor of the patients with a PSA level after neoadjuvant hormonal deprivation therapy of {<=}1 ng/mL. The overall survival rate was 94% vs. 77.5% (p = 0.0045), and the disease-specific survival rate at 4 years was 98.5% vs. 82.5%. Conclusions: The results of our study have shown that patients with a PSA level >1 ng/mL at the beginning of external beam radiotherapy after {>=}2 months of neoadjuvant luteinizing hormone-releasing hormone agonist therapy have a significantly greater rate of biochemical failure and lower survival rate compared with those with a PSA level of {<=}1 ng/mL. Patients without adequate PSA suppression should be considered a higher risk group and considered for dose escalation or the use of novel treatments.

  14. Adsorption of gases on carbon molecular sieves

    SciTech Connect

    Vyas, S.N.; Patwardhan, S.R.; Vijayalakshmi, S. . Dept. of Chemical Engineering); Ganesh, K.S. )

    1994-12-01

    Adsorption on carbon molecular sieves (CMS) prepared by coke deposition has become an interesting area of adsorption due to its microporous nature and favorable separation factor on size and shape selectivity basis for many gaseous systems. In the present work CMS was synthesized from coconut shell through three major steps, namely, carbonization, activation, and coke deposition by hydrocarbon cracking. The crushed, washed, and sieved granules of coconut shell (particle size 2--3 mm) were pretreated with sodium silicate solution and oven-dried at 150 C to create the inorganic sites necessary for coke deposition. Carbonization and activation of the dried granules were carried out at 800 C, for 30 min each. The activated char thus produced was subjected to hydrocarbon cracking at 600 C for periods varying from 30 to 180 min. The product samples were characterized in terms of adsorption isotherm, kinetic adsorption curve, surface area, pore volume, pore size distribution, and characteristic energy for adsorption by using O[sub 2], N[sub 2], C[sub 2]H[sub 2], CO[sub 2], C[sub 3]H[sub 6], and CH[sub 4].

  15. 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.

  16. Adsorption of small organic molecules on graphene.

    PubMed

    Lazar, Petr; Karlický, František; Jurečka, Petr; Kocman, Mikuláš; Otyepková, Eva; Šafářová, Klára; Otyepka, Michal

    2013-04-24

    We present a combined experimental and theoretical quantification of the adsorption enthalpies of seven organic molecules (acetone, acetonitrile, dichloromethane, ethanol, ethyl acetate, hexane, and toluene) on graphene. Adsorption enthalpies were measured by inverse gas chromatography and ranged from -5.9 kcal/mol for dichloromethane to -13.5 kcal/mol for toluene. The strength of interaction between graphene and the organic molecules was estimated by density functional theory (PBE, B97D, M06-2X, and optB88-vdW), wave function theory (MP2, SCS(MI)-MP2, MP2.5, MP2.X, and CCSD(T)), and empirical calculations (OPLS-AA) using two graphene models: coronene and infinite graphene. Symmetry-adapted perturbation theory calculations indicated that the interactions were governed by London dispersive forces (amounting to ∼60% of attractive interactions), even for the polar molecules. The results also showed that the adsorption enthalpies were largely controlled by the interaction energy. Adsorption enthalpies obtained from ab initio molecular dynamics employing non-local optB88-vdW functional were in excellent agreement with the experimental data, indicating that the functional can cover physical phenomena behind adsorption of organic molecules on graphene sufficiently well.

  17. Adsorption in sparse networks. 1: Cylinder model

    SciTech Connect

    Scherer, G.W.

    1998-06-15

    Materials with very low density, such as aerogels, are networks with polymers or chains of particles joined at nodes, where the spacing of the nodes is large compared to the thickness of the chains. In such a material, most of the solid surface has positive curvature, so condensation of an adsorbate is more difficult than condensation in a body containing cavities whose surfaces have negative curvature. A model is presented in which the network is represented by straight cylinders joined at nodes with coordination numbers 4, 6, or 12. The shape of the adsorbate/adsorptive interface is obtained for each network by minimizing its surface area. The adsorption behavior is found to depend on the ratio of the node separation, l, to the radius of the cylinders, a: if l/a exceeds a critical value (which depends on the coordination of the node), then the curvature of the adsorbate/adsorptive interface approaches zero while the adsorbate occupies a small fraction of the pore volume; if l/a is less than the critical value, then condensation occurs. Even in the latter case, interpretation of the adsorption isotherm in terms of cylindrical pores (as in the BJH model) yields apparent pore sizes much greater than the actual spacing of the nodes. In a companion paper, this model is applied to silica aerogels and found to give a good fit to both the adsorption and desorption curves with a single distribution of node spacings.

  18. Adsorption of reovirus by minerals and soils.

    PubMed Central

    Moore, R S; Taylor, D H; Reddy, M M; Sturman, L S

    1982-01-01

    Adsorption of [35S]methionine-labeled reovirus by 30 dry soils, minerals, and finely ground rocks suspended in synthetic freshwater at pH 7 was investigated to determine the conditions necessary for optimum virus removal during land application of wastewaters. All of the minerals and soils studied were excellent adsorbents of reovirus, with greater than 99% of the virus adsorbed after 1 h at 4 degrees C. Thereafter, virus remaining in suspension was significantly inactivated, and within 24 h a three to five log10 reduction in titer occurred. The presence of divalent cations, i.e., Ca2+ and Mg2+, in synthetic freshwater enhanced removal, whereas soluble organic matter decreased the amount of virus adsorbed in secondary effluent. The amount of virus adsorbed by these substrates was inversely correlated with the amount of organic matter, capacity to adsorb cationic polyelectrolyte, and electrophoretic mobility. Adsorption increased with increasing available surface area, as suspended infectivity was reduced further by the more finely divided substrates. However, the organic content of the soils reduced the level of infectious virus adsorbed below that expected from surface area measurements alone. The inverse correlation between virus adsorption and substrate capacity for cationic polyelectrolyte indicates that the adsorption of infectious reovirus particles is predominately a charged colloidal particle-charged surface interaction. Thus, adsorption of polyelectrolyte may be useful in predicting the fate of viruses during land application of sewage effluents and sludges. PMID:7149717

  19. Membrane Potential Generated by Ion Adsorption

    PubMed Central

    Tamagawa, Hirohisa; Morita, Sachi

    2014-01-01

    It has been widely acknowledged that the Goldman-Hodgkin-Katz (GHK) equation fully explains membrane potential behavior. The fundamental facet of the GHK equation lies in its consideration of permeability of membrane to ions, when the membrane serves as a separator for separating two electrolytic solutions. The GHK equation describes that: variation of membrane permeability to ion in accordance with ion species results in the variation of the membrane potential. However, nonzero potential was observed even across the impermeable membrane (or separator) separating two electrolytic solutions. It gave rise to a question concerning the validity of the GHK equation for explaining the membrane potential generation. In this work, an alternative theory was proposed. It is the adsorption theory. The adsorption theory attributes the membrane potential generation to the ion adsorption onto the membrane (or separator) surface not to the ion passage through the membrane (or separator). The computationally obtained potential behavior based on the adsorption theory was in good agreement with the experimentally observed potential whether the membrane (or separator) was permeable to ions or not. It was strongly speculated that the membrane potential origin could lie primarily in the ion adsorption on the membrane (or separator) rather than the membrane permeability to ions. It might be necessary to reconsider the origin of membrane potential which has been so far believed explicable by the GHK equation. PMID:24957176

  20. Preliminary Report on Monosodium Titanate Adsorption Kinetics

    SciTech Connect

    Hobbs, D.T.

    1998-12-11

    The Salt Disposition Systems Engineering Team identified the adsorption kinetics of actinides and strontium onto monosodium titanate (MST) as a technical risk for several of the processing alternatives selected for additional evaluation in Phase III of their effort. The Flow Sheet Team requested that the Savannah River Technology Center (SRTC) examine the adsorption kinetics of MST for several process alternatives.This study consisted of a statistically designed set of tests to determine the rate of adsorption of strontium, uranium, neptunium and plutonium as a function of temperature, MST concentration, and concentrations of sodium, strontium, uranium, neptunium and plutonium. Additional tests incorporated into the design assess the effects of mixing as well as the influence from the presence of sludge solids and sodium tetraphenylborate.

  1. GENERAL: Cluster Growth Through Monomer Adsorption Processes

    NASA Astrophysics Data System (ADS)

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

    2010-02-01

    We propose a monomer adsorption model, in which only the monomers are allowed to diffuse and adsorb onto other clusters. By means of the generalized rate equation we investigate the kinetic behavior of the system with a special rate kernel. For the system without monomer input, the concentration aj(t) of the Aj clusters (j > 1) asymptotically retains a nonzero quantity, while for the system with monomer input, it decays with time and vanishes finally. We also investigate the kinetics of an interesting model with fixed-rate monomer adsorption. For the case without monomer source, the evolution of the system will halt at a finite time; while the system evolves infinitely in time in the case with monomer source. Finally, we also suggest a connection between the fixed-rate monomer adsorption systems and growing networks.

  2. Novel nano bearings constructed by physical adsorption

    NASA Astrophysics Data System (ADS)

    Zhang, Yongbin

    2015-09-01

    The paper proposes a novel nano bearing formed by the physical adsorption of the confined fluid to the solid wall. The bearing is formed between two parallel smooth solid plane walls sliding against one another, where conventional hydrodynamic lubrication theory predicted no lubricating effect. In this bearing, the stationary solid wall is divided into two subzones which respectively have different interaction strengths with the lubricating fluid. It leads to different physical adsorption and slip properties of the lubricating fluid at the stationary solid wall respectively in these two subzones. It was found that a significant load-carrying capacity of the bearing can be generated for low lubricating film thicknesses, because of the strong physical adsorption and non-continuum effects of the lubricating film.

  3. Cotton cellulose: enzyme adsorption and enzymic hydrolysis

    SciTech Connect

    Beltrame, P.L.; Carniti, P.; Focher, B.; Marzetti, A.; Cattaneo, M.

    1982-01-01

    The adsorption of a crude cellulase complex from Trichoderma viride on variously pretreated cotton cellulose samples was studied in the framework of the Langmuir approach at 2-8 degrees. The saturation amount of adsorbed enzyme was related to the susceptibility of the substrates to hydrolysis. In every case the adsorption process was faster by 2-3 orders of magnitude than the hydrolysis step to give end products. For ZnCl/sub 2/-treated cotton cellulose the Langmuir parameters correlated fairly well with the value of the Michaelis constant, measured for its enzymic hydrolysis, and the adsorptive complex was indistinguishable from the complex of the Michaelis-Menten model for the hydrolysis.

  4. Porous silicon functionalization for possible arsenic adsorption

    NASA Astrophysics Data System (ADS)

    Balderas-Valadez, Ruth Fabiola; Agarwal, Vivechana

    2014-09-01

    Thiol-functionalized porous silicon (PS) monolayer was evaluated for its possible application in As (III) adsorption. Dimercaptosuccinic acid (DMSA) attached to mesoporous silicon via amide bond linkages was used as a chelate for As (III). Two different aminosilanes namely 3-(aminopropyl) triethoxysilane (APTES) and 3-aminopropyl (diethoxy)-methylsilane (APDEMS) were tested as linkers to evaluate the relative response for DMSA attachment. The aminosilane-modified PS samples were attached to DMSA by wet impregnation followed by the adsorption of As (III). Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) have been used to identify the functional groups and to estimate the As (III) content, respectively. FTIR spectroscopy confirmed the covalent bonding of DMSA with amide and R-COOH groups on the nanostructured porous surface. XPS confirms the preferred arsenic adsorption on the surface of PS/DMSA samples as compared to the aminosilane-modified and bare PS substrates.

  5. Utilisation of chitinous materials in pigment adsorption.

    PubMed

    Wang, San-Lang; Chen, Yan-Cheng; Yen, Yue-Horng; Liang, Tzu-Wen

    2012-12-01

    The effect of adding the cells of four lactobacilli to a squid pen powder (SPP)-containing medium on prodigiosin (PG) production by Serratia marcescens TKU011 is examined. The best increase in PG productivity was shown by strain TKU012. Among the samples of strain TKU012 and the chitinous materials of cicada casting powder (CCP), shrimp shell powder (SSP), squid pen powder (SPP), α-chitin, and β-chitin, TKU012 cells displayed the best adsorption rate (84%) for PG, followed by CCP, SSP, SPP, α-chitin, and β-chitin. As for the water-soluble food colourants, Allura Red AC (R40) and Tartrazne (Y4), SPP and SSP had better adsorptive powers than pure chitin preparations, strain TKU012, and CCP. Treatment with organic solvents, hot alkali, or proteases (papain, bromelain) diminished the adsorption rates of the biosorbents.

  6. Adsorption properties of thermally sputtered calcein film

    NASA Astrophysics Data System (ADS)

    Kruglenko, I.; Burlachenko, J.; Kravchenko, S.; Savchenko, A.; Slabkovska, M.; Shirshov, Yu.

    2014-05-01

    High humidity environments are often found in such areas as biotechnology, food chemistry, plant physiology etc. The controlling of parameters of such ambiences is vitally important. Thermally deposited calcein films have extremely high adsorptivity at exposure to water vapor of high concentration. This feature makes calcein a promising material for humidity sensing applications. The aim of this work is to explain high sensitivity and selectivity of calcein film to high humidity. Quartz crystal microbalance sensor, AFM and ellipsometry were used for calcein film characterization and adsorption properties investigation. The proposed model takes into account both the molecular properties of calcein (the presence of several functional groups capable of forming hydrogen bonds, and their arrangement) and the features of structure of thermally deposited calcein film (film restructuring due to the switching of bonds "calcein-calcein" to "calcein-water" in the course of water adsorption).

  7. Porous silicon functionalization for possible arsenic adsorption

    PubMed Central

    2014-01-01

    Thiol-functionalized porous silicon (PS) monolayer was evaluated for its possible application in As (III) adsorption. Dimercaptosuccinic acid (DMSA) attached to mesoporous silicon via amide bond linkages was used as a chelate for As (III). Two different aminosilanes namely 3-(aminopropyl) triethoxysilane (APTES) and 3-aminopropyl (diethoxy)-methylsilane (APDEMS) were tested as linkers to evaluate the relative response for DMSA attachment. The aminosilane-modified PS samples were attached to DMSA by wet impregnation followed by the adsorption of As (III). Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) have been used to identify the functional groups and to estimate the As (III) content, respectively. FTIR spectroscopy confirmed the covalent bonding of DMSA with amide and R-COOH groups on the nanostructured porous surface. XPS confirms the preferred arsenic adsorption on the surface of PS/DMSA samples as compared to the aminosilane-modified and bare PS substrates. PMID:25249826

  8. Adsorption on Highly Ordered Porous Alumina

    NASA Astrophysics Data System (ADS)

    Mistura, Giampaolo; Bruschi, Lorenzo; Lee, Woo

    2016-10-01

    Porous anodic aluminum oxide (AAO) is characterized by a regular arrangement of the pores with a narrow pore size distribution over extended areas, uniform pore depth, and solid pore walls without micropores. Thanks to significant improvements in anodization techniques, structural engineering of AAO allows to accurately tailor the pore morphology. These features make porous AAO an excellent substrate to study adsorption phenomena. In this paper, we review recent experiments involving the adsorption in porous AAO. Particular attention will be devoted to adsorption in straight and structured pores with a closed end which shed new light on fundamental issues like the origin of hysteresis in closed end pores and the nature of evaporation from ink-bottle pores. The results will be compared to those obtained in other synthetic materials like porous silicon and silica.

  9. 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

  10. 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.

  11. The adsorption of polyelectrolytes on nanoparticles

    NASA Astrophysics Data System (ADS)

    Gao, Jun

    The adsorption of poly(N- isopropylacrylainide) (PNIPAM) and gelatin on surfactant- free polystyrene (PS) nanoparticles has been investigated by a combination of static and dynamic laser light scattering (LLS). We found that the coil-to-globule transition of thermo-sensitive PNIPAM chains at PS hydrophobic surface was three degrees lower than the lower critical solution temperature (LCST) of the free PNIPAM chains in water. The transition at surface in turn increased the adsorbed amount by additional adsorption when the temperature increased across the LCST. We established a method based on static LLS to calculate the adsorbed amount. By combining with dynamic LLS measurements, we were able to calculate the average density of the adsorbed layer. We made a general conclusion: For long linear flexible polymer chains adsorbed on a spherical surface driven by hydrophobic attraction, the volume of the adsorbed layer is proportional to the square of the adsorbed amount. We further proposed a simple scaling of the density profile for linear polymer chains on hydrophobic surface. For the adsorption of amphoteric polyelectrolyte gelatin on the same PS nanoparticles, we found that if pure water is used as a dispersing agent, the adsorption was driven by electrostatic attraction. However, by pre-dissolving gelatin in small amount of formamide and then repeating the adsorption processes, the adsorption was switched to the hydrophobic attraction driving and the same relationship between the shell volume and the adsorbed amount as that for PNIPAM/PS system recurred. Formamide is believed to have screened out the electrostatic interactions and possible hydrogen binding. We also found a general structural model in the study of different polymeric dispersions: the surface area per-stabilizer occupied is a constant; and successfully applied this model to the core-shell nanostructure formed by the self- assembly of block copolymer micelles. The preparation of narrowly distributed PS

  12. Protein adsorption to multi-component glasses

    NASA Astrophysics Data System (ADS)

    Hall, Matthew Micah

    2003-07-01

    The adsorption of human serum albumin (HSA) to sodium silicate, soda lime silicate (SLS), and sodium aluminosilicate (SAS) glass microspheres was investigated using sodiumdodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in conjunction with a colloidal silver stain for visualization. The 30 Na2O·70 SiO2 composition could not be evaluated due to an apparent chemical interference that occurred during silver staining. This inhibitory effect was attributed to the extensive corrosion that occurred during the protein elution and caused an elevation in the pH of the solution. The remaining glass compositions were sufficiently durable for further study. The HSA adsorption capacity of SLS glass microspheres containing 70 and 80 mol% SiO2 increased as CaO was substituted for Na2O. An abrupt decrease in the HSA adsorption capacity was observed for SLS glasses containing 60 mol% SiO2. A similar trend was observed for the SAS glass microspheres, although the SAS glasses adsorbed less HSA than the SLS glasses containing equivalent molar percentages of SiO2. The initial increase in HSA adsorption capacity for SLS and SAS glasses containing 70 and 80 MOM SiO2 was attributed to the introduction of positive charges into the glass surfaces via Ca2+ and Al3+ cations. The decrease in HSA adsorption capacity for SLS and SAS glasses containing 60 mol% SiO2 may be due to an enhanced affinity between the glasses and HSA, resulting in a "flattened" conformation that limits the total accessible area for adsorption.

  13. Adsorption of Gases on Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Mbaye, Mamadou Thiao

    This research focus in studying the interaction between various classical and quantum gases with novel carbon nanostructures, mainly carbon nanotubes (CNTs). Since their discovery by the Japanese physicist Sumio Iijima [1] carbon nanotubes have, experimentally and theoretically, been subjected to many scientific investigation. Studies of adsorption on CNTs are particularly directed toward their better usage in gas storage, gas separation, catalyst, drug delivery, and water purification. We explore the adsorption of different gases entrapped in a single, double, or multi-bundles of CNTs using computer simulations. The first system we investigate consists of Ar and Kr films adsorbed on zigzag or armchair nanotubes. Our simulations revealed that Kr atoms on intermediate size zigzag NTs undergo two phase transitions: A liquid-vapor (L→V), and liquid-commensurate (L→CS) with a fractional coverage of one Kr atoms adsorbed for every four carbon atoms. For Ar on zigzag and armchair NTs, the only transition observed is a L→V. In the second problem, we explore the adsorption of CO2 molecules in a nanotube bundle and calculate the isosteric heat of adsorption of the entrapped molecules within the groove. We observed that the lower the temperature, the higher the isosteric of adsorption. Last, we investigate the adsorption of hydrogen, Helium, and Neon gases on the groove site of two parallel nanotubes. At low temperature, the transverse motion on the plane perpendicular to the tubes' axis is frozen out and as a consequence, the heat capacity is reduced to 1/2. At high temperature, the atoms gain more degree of freedom and as a consequence the heat capacity is 5/2.

  14. Database for protein adsorption: update on developments

    NASA Astrophysics Data System (ADS)

    Paszek, Ewa; Vasina, Elena N.; Nicolau, Dan V.

    2008-12-01

    Protein adsorption at solid-liquid interfaces is critical to many applications, including biomaterials, protein microarrays and lab-on-a-chip devices. Despite this general interest, and a large amount of research in the last half a century, protein adsorption cannot be predicted with an engineering level, design-orientated accuracy. Here we describe a Biomolecular Adsorption Database (BAD), freely available online, which archives the published protein adsorption data. Piecewise linear regression with breakpoint applied to the data in the BAD suggests that the input variables to protein adsorption, i.e., protein concentration in solution; protein descriptors derived from primary structure (number of residues, protein hydrophobicity and spread of amino acid hydrophobicity, isoelectric point); surface descriptors (contact angle); and fluid environment descriptors (pH, ionic strength), correlate well with the output variable - the protein concentration on the surface. Furthermore, neural network analysis revealed that the size of the BAD makes it sufficiently representative, with a neural network-based predictive error of 5% or less. Interestingly, a consistently better fit is obtained if the BAD is divided into two separate subsets representing protein adsorption on hydrophilic and hydrophobic surfaces. Based on these findings, selected entries from the BAD have been used to construct neural network-based estimation routines, which predict the amount of adsorbed protein, the thickness of the absorbed layer and the surface tension of the proteincovered surface. While the BAD is of general interest, the prediction of the thickness and the surface tension of the protein-covered layers are of particular relevance to the design of microfluidics devices.

  15. Adsorptive Removal and Adsorption Kinetics of Fluoroquinolone by Nano-Hydroxyapatite.

    PubMed

    Chen, Yajun; Lan, Tao; Duan, Lunchao; Wang, Fenghe; Zhao, Bin; Zhang, Shengtian; Wei, Wei

    2015-01-01

    Various kinds of antibiotics, especially fluoroquinolone antibiotics (FQs) have been widely used for the therapy of infectious diseases in human and livestock. For their poorly absorbed by living organisms, large-scale misuse or abuse of FQs will foster drug resistance among pathogenic bacteria, as well as a variety of environmental problems when they were released in the environment. In this work, the adsorption properties of two FQs, namely norfloxacin (NOR) and ciprofloxacin (CIP), by nano-hydroxyapatite (n-HAP) were studied by batch adsorption experiments. The adsorption curves of FQs by n-HAP were simulated by Langmuir and Freundlich isotherms. The results shown that NOR and CIP can be adsorbed effectively by the adsorbent of n-HAP, and the adsorption capacity of FQs increase with increasing dosage of n-HAP. The optimum dosage of n-HAP for FQs removal was 20 g · L(-1), in which the removal efficiencies is 51.6% and 47.3%, and an adsorption equilibrium time is 20 min. The maximum removal efficiency occurred when pH is 6 for both FQs. The adsorption isotherm of FQs fits well for both Langmuir and Freundlich equations. The adsorption of both FQs by n-HAP follows second-order kinetics. PMID:26698573

  16. Applications and limits of theoretical adsorption models for predicting the adsorption properties of adsorbents.

    PubMed

    Park, Hyun Ju; Nguyen, Duc Canh; Na, Choon-Ki; Kim, Chung-il

    2015-01-01

    The objective of this study is to evaluate the applicability of adsorption models for predicting the properties of adsorbents. The kinetics of the adsorption of NO3- ions on a PP-g-AA-Am non-woven fabric have been investigated under equilibrium conditions in both batch and fixed bed column processes. The adsorption equilibrium experiments in the batch process were carried out under different adsorbate concentration and adsorbent dosage conditions and the results were analyzed using adsorption isotherm models, energy models, and kinetic models. The results of the analysis indicate that the adsorption occurring at a fixed adsorbate concentration with a varying adsorbent dosage occur more easily compared to those under a fixed adsorbent dosage with a varying adsorbate concentration. In the second part of the study, the experimental data obtained using fixed bed columns were fit to Bed Depth Service Time, Bohart-Adams, Clark, and Wolborska models, to predict the breakthrough curves and determine the column kinetic parameters. The adsorption properties of the NO3- ions on the PP-g-AA-Am non-woven fabric were differently described by different models for both the batch and fixed bed column process. Therefore, it appears reasonable to assume that the adsorption properties were dominated by multiple mechanisms, depending on the experimental conditions.

  17. Adsorptive Removal and Adsorption Kinetics of Fluoroquinolone by Nano-Hydroxyapatite

    PubMed Central

    Chen, Yajun; Lan, Tao; Duan, Lunchao; Wang, Fenghe; Zhao, Bin; Zhang, Shengtian; Wei, Wei

    2015-01-01

    Various kinds of antibiotics, especially fluoroquinolone antibiotics (FQs) have been widely used for the therapy of infectious diseases in human and livestock. For their poorly absorbed by living organisms, large-scale misuse or abuse of FQs will foster drug resistance among pathogenic bacteria, as well as a variety of environmental problems when they were released in the environment. In this work, the adsorption properties of two FQs, namely norfloxacin (NOR) and ciprofloxacin (CIP), by nano-hydroxyapatite (n-HAP) were studied by batch adsorption experiments. The adsorption curves of FQs by n-HAP were simulated by Langmuir and Freundlich isotherms. The results shown that NOR and CIP can be adsorbed effectively by the adsorbent of n-HAP, and the adsorption capacity of FQs increase with increasing dosage of n-HAP. The optimum dosage of n-HAP for FQs removal was 20 g·L-1, in which the removal efficiencies is 51.6% and 47.3%, and an adsorption equilibrium time is 20 min. The maximum removal efficiency occurred when pH is 6 for both FQs. The adsorption isotherm of FQs fits well for both Langmuir and Freundlich equations. The adsorption of both FQs by n-HAP follows second-order kinetics. PMID:26698573

  18. Initial stages of adsorption in the Cu/Si( 1 1 1 ) system

    NASA Astrophysics Data System (ADS)

    Shukrinov, P.; Savchenkov, A.; Mutombo, P.; Cháb, V.; Slezák, J.

    2002-05-01

    The adsorption of Cu atoms on a Si(1 1 1)-7×7 surface was studied using scanning tunnelling microscopy. Two different kinds of clusters were found at room temperature and we associate them with copper atoms embedded in subsurface layers. Short annealing at ˜550 °C stimulates a reaction, leading to the substitution of corner Si adatoms in the 7×7 unit cell. This configuration is stable with respect to continuing thermal processing.

  19. [Fluoride adsorption form drinking water by granular lanthanum alginate].

    PubMed

    Huo, Ya-Kun; Ding, Wen-Ming; Huang, Xia

    2010-11-01

    Granular lanthanum alginate was prepared by dripping solved sodium alginate into lanthanum chloride solution. After washed and dried, sorbent with 1-1.5 mm diameter, 25% (mass fraction) La content was made and applied for fluoride removal from drinking test. Adsorption performance such as adsorption rate, adsorption isotherm, pH and disturbing ions effects were tested in batch adsorption. The changes of adsorbent surface and the solution composition before and after adsorption were also studied. Results showed that the adsorption rate was fast, fluoride concentration trend to stable after 2h reaction, and the adsorption rate fit for pseudo second order equation. The adsorption was significantly affected by pH and some disturbing ions, optimum pH = 4, phosphate and carbonate reduced adsorption. Adsorption isotherm fitted Langmuir equation well; the max adsorption capacity was 197.2 mg x g(-1). SEM photographs of sorbent before and after adsorption showed significantly different surface morphology; EDX composition analysis of sorbent surface and solution concentration changes before and after adsorption showed that ion exchange take placed between solution F- and sorbent surface Cl- and OH-.

  20. Neutrophil-to-Lymphocyte Ratio Predicts PSA Response and Prognosis in Prostate Cancer: A Systematic Review and Meta-Analysis.

    PubMed

    Cao, Jian; Zhu, Xuan; Zhao, Xiaokun; Li, Xue-Feng; Xu, Ran

    2016-01-01

    An unprecedented advance has been seen in castration-resistant prostate cancer (CRPC) treatments in the past few years. With a number of novel agents were approved, there is a pressing need to develop improved prognostic biomarkers to facilitate the personalised selection and sequencing of these novel agents. Emerging evidence indicates that the neutrophil-to-lymphocyte ratio (NLR) is associated with poorer survival in patients with prostate cancer (PCa). However, the importance of the NLR for the prediction of the PSA response (PSARS) and biochemical recurrence (BCR) has been largely neglected. Here, we conducted a systematic review and meta-analysis to evaluate the prognostic value of the NLR for the PSARS, BCR, and survival in PCa. A systematic database search was performed using Embase, PubMed, the Cochrane Library, and the China National Knowledge Infrastructure (CNKI). A meta-analysis was performed by pooling hazard ratios (HRs), odds ratios (ORs) and the corresponding 95% confidence intervals (CIs). A total of 22 studies were included in the meta-analysis. Our results suggest that an elevated NLR predicts a lower PSARS rate (OR = 1.69, 95% CI: 1.40-1.98) and a higher possibility of BCR (HR = 1.12, 95% CI: 1.02-1.21). Additionally, we confirmed that an elevated NLR was a prognostic predictor of shorter overall survival (OS) in both metastatic castration-resistant PCa (mCRPC) (HR = 1.45, 95% CI: 1.32-1.59) and localized PCa (LPC) (HR = 1.12, 95% CI: 1.01-1.23) and that it predicted worse progression-free survival (PFS) in CRPC (HR = 1.42, 95% CI: 1.23-1.61) and poorer recurrence-free survival (RFS) (HR = 1.38, 95%CI: 1.01-1.75) in LPC. Our results suggest that an elevated NLR might be employed as a prognostic marker of biochemical changes and prognosis to facilitate risk stratification and decision making for individual treatment of PCa patients. The potential mechanisms underlying these associations and future research directions are also discussed. PMID

  1. Neutrophil-to-Lymphocyte Ratio Predicts PSA Response and Prognosis in Prostate Cancer: A Systematic Review and Meta-Analysis

    PubMed Central

    Zhao, Xiaokun; Li, Xue-Feng; Xu, Ran

    2016-01-01

    An unprecedented advance has been seen in castration-resistant prostate cancer (CRPC) treatments in the past few years. With a number of novel agents were approved, there is a pressing need to develop improved prognostic biomarkers to facilitate the personalised selection and sequencing of these novel agents. Emerging evidence indicates that the neutrophil-to-lymphocyte ratio (NLR) is associated with poorer survival in patients with prostate cancer (PCa). However, the importance of the NLR for the prediction of the PSA response (PSARS) and biochemical recurrence (BCR) has been largely neglected. Here, we conducted a systematic review and meta-analysis to evaluate the prognostic value of the NLR for the PSARS, BCR, and survival in PCa. A systematic database search was performed using Embase, PubMed, the Cochrane Library, and the China National Knowledge Infrastructure (CNKI). A meta-analysis was performed by pooling hazard ratios (HRs), odds ratios (ORs) and the corresponding 95% confidence intervals (CIs). A total of 22 studies were included in the meta-analysis. Our results suggest that an elevated NLR predicts a lower PSARS rate (OR = 1.69, 95% CI: 1.40–1.98) and a higher possibility of BCR (HR = 1.12, 95% CI: 1.02–1.21). Additionally, we confirmed that an elevated NLR was a prognostic predictor of shorter overall survival (OS) in both metastatic castration-resistant PCa (mCRPC) (HR = 1.45, 95% CI: 1.32–1.59) and localized PCa (LPC) (HR = 1.12, 95% CI: 1.01–1.23) and that it predicted worse progression-free survival (PFS) in CRPC (HR = 1.42, 95% CI: 1.23–1.61) and poorer recurrence-free survival (RFS) (HR = 1.38, 95%CI: 1.01–1.75) in LPC. Our results suggest that an elevated NLR might be employed as a prognostic marker of biochemical changes and prognosis to facilitate risk stratification and decision making for individual treatment of PCa patients. The potential mechanisms underlying these associations and future research directions are also

  2. Visually Estimated MRI Targeted Prostate Biopsy Could Improve the Detection of Significant Prostate Cancer in Patients with a PSA Level <10 ng/mL

    PubMed Central

    Lee, Dong Hoon; Nam, Jong Kil; Park, Sung Woo; Lee, Seung Soo; Han, Ji-Yeon; Lee, Sang Don; Lee, Joon Woo

    2016-01-01

    Purpose To compare prostate cancer detection rates between 12 cores transrectal ultrasound-guided prostate biopsy (TRUS-Bx) and visually estimated multiparametric magnetic resonance imaging (mp-MRI)-targeted prostate biopsy (MRI-visual-Bx) for patients with prostate specific antigen (PSA) level less than 10 ng/mL. Materials and Methods In total, 76 patients with PSA levels below 10 ng/mL underwent 3.0 Tesla mp-MRI and TRUS-Bx prospectively in 2014. In patients with abnormal lesions on mp-MRI, we performed additional MRI-visual-Bx. We compared pathologic results, including the rate of clinically significant prostate cancer cores (cancer length greater than 5 mm and/or any Gleason grade greater than 3 in the biopsy core). Results The mean PSA was 6.43 ng/mL. In total, 48 of 76 (63.2%) patients had abnormal lesions on mp-MRI, and 116 targeted biopsy cores, an average of 2.42 per patient, were taken. The overall detection rates of prostate cancer using TRUS-Bx and MRI-visual-Bx were 26/76 (34.2%) and 23/48 (47.9%), respectively. In comparing the pathologic results of TRUS-Bx and MRI-visual-Bx cores, the positive rates were 8.4% (77 of 912 cores) and 46.6% (54 of 116 cores), respectively (p<0.001). Mean cancer core lengths and mean cancer core percentages were 3.2 mm and 24.5%, respectively, in TRUS-Bx and 6.3 mm and 45.4% in MRI-visual-Bx (p<0.001). In addition, Gleason score ≥7 was noted more frequently using MRI-visual-Bx (p=0.028). The detection rate of clinically significant prostate cancer was 27/77 (35.1%) and 40/54 (74.1%) for TRUS-Bx and MRI-visual-Bx, respectively (p<0.001). Conclusion MRI-visual-Bx showed better performance in the detection of clinically significant prostate cancer, compared to TRUS-Bx among patients with a PSA level less than 10 ng/mL. PMID:26996553

  3. PSA Response to Lenalidomide Therapy in a Pre-Treated Patient with Metastatic Prostate Cancer Refractory to Hormones and Chemotherapy: A Case Report

    PubMed Central

    Gasent Blesa, Joan Manel; Godoy, Miguel Peris; Esparcia, María Fonfría; Mollá, Sara Blasco; Magán, Balbino Mancheño; Sempere Ortells, José Miguel; Sánchez, José Luis

    2012-01-01

    Hormone-resistant prostate cancer (HRPC) occurs when prostate cancer is no longer responsive to hormone therapy. Treatment options are limited, and there is a clear necessity for therapies that improve outcome. Preclinical and clinical evidence supports the role of the immunomodulatory agent lenalidomide in HRPC. In this paper, we report that lenalidomide showed antitumoral activity in a patient with HRPC and bone metastases pre-treated with chemotherapy, decreased the PSA level and improved the patient's health status for the first 5 months. It is important to emphasize that it was not associated with hematologic toxicity. PMID:22666210

  4. Adsorption of herbicides using activated carbons

    SciTech Connect

    Derbyshire, F.; Jagtoyan, M.; Lafferty, C.; Kimber, G.

    1996-10-01

    This work describes development of a series of novel activated carbon materials and their testing for possible water treatment applications by studying the adsorption of sodium pentachlorphenolate, PCP (a common herbicide/wood preservative). Although the application of activated carbons is an established technology for the treatment of public water supplies, there is a growing need for materials with higher selectivity and adsorptive capacities as well as high abrasion resistance. The materials that will be discussed include extruded wood-derived carbons with novel pore size distributions and high hardness, as well as activated carbon fiber composites. Comparisons will be made with commercial granular water treatment carbons.

  5. Well Completion Report for Corrective Action Unit 447, Project Shoal Area, Churchill County, Nevada, Rev. No.: 0

    SciTech Connect

    Rick Findlay

    2006-09-01

    This Well Completion Report is being provided as part of the implementation of the Corrective Action Decision Document (CADD)/Corrective Action Plan (CAP) for Corrective Action Unit (CAU) 447 (NNSA/NSO, 2006a). The CADD/CAP is part of an ongoing U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (NNSA/NSO) funded project for the investigation of CAU 447 at the Project Shoal Area (PSA). All work performed on this project was conducted in accordance with the ''Federal Facility Agreement and Consent Order'' (FFACO) (1996), and all applicable Nevada Division of Environmental Protection (NDEP) policies and regulations. Investigation activities included the drilling, construction, and development of three monitoring/validation (MV) wells at the PSA. This report summarizes the field activities and data collected during the investigation.

  6. Density Functional Theory Study of Hydrogen Adsorption in a Ti-Decorated Mg-Based Metal-Organic Framework-74.

    PubMed

    Suksaengrat, Pitphichaya; Amornkitbamrung, Vittaya; Srepusharawoot, Pornjuk; Ahuja, Rajeev

    2016-03-16

    The Ti-binding energy and hydrogen adsorption energy of a Ti-decorated Mg-based metal-organic framework-74 (Mg-MOF-74) were evaluated by using first-principles calculations. Our results revealed that only three Ti adsorption sites were found to be stable. The adsorption site near the metal oxide unit is the most stable. To investigate the hydrogen-adsorption properties of Ti-functionalized Mg-MOF-74, the hydrogen-binding energy was determined. For the most stable Ti adsorption site, we found that the hydrogen adsorption energy ranged from 0.26 to 0.48 eV H2 (-1) . This is within the desirable range for practical hydrogen-storage applications. Moreover, the hydrogen capacity was determined by using ab initio molecular dynamics simulations. Our results revealed that the hydrogen uptake by Ti-decorated Mg-MOF-74 at temperatures of 77, 150, and 298 K and ambient pressure were 1.81, 1.74, and 1.29 H2  wt %, respectively. PMID:26717417

  7. Influence of Environmental Factors on the Adsorption Capacity and Thermal Conductivity of Silica Nano-Porous Materials.

    PubMed

    Zhang, Hu; Gu, Wei; Li, Ming-Jia; Fang, Wen-Zhen; Li, Zeng-Yao; Tao, Wen-Quan

    2015-04-01

    In this work, the influence of temperature and humidity environment on the water vapor adsorption capacity and effective thermal conductivity of silica nano-porous material is conducted within a relative humidity range from 15% to 90% at 25 °C, 40 °C and 55 °C, respectively. The experiment results show that both the temperature and relative humidity have significant influence on the adsorption capacity and effective thermal conductivity of silica nano-porous materials. The adsorption capacity and effective thermal conductivity increase with humidity because of the increases of water vapor concentration. The effective thermal conductivity increases linearly with adsorption saturation capacity at constant temperature. Because adsorption process is exothermic reaction, the increasing temperature is not conducive to the adsorption. But the effective thermal conductivity increases with the increment of temperature at the same water uptake because of the increment of water thermal conductivity with temperature Geometric models and unit cell structure are adopted to predict the effective thermal conductivity and comparisons with the experimental result are made, and for the case of moist silica nano-porous materials with high porosity no quantitative agreement is found. It is believed that the adsorbed water will fill in the nano-pores and gap and form lots of short cuts, leading to a significant reduction of the thermal resistance.

  8. Unit Cells

    ERIC Educational Resources Information Center

    Olsen, Robert C.; Tobiason, Fred L.

    1975-01-01

    Describes the construction of unit cells using clear plastic cubes which can be disassembled, and one inch cork balls of various colors, which can be cut in halves, quarters, or eighths, and glued on the inside face of the cube, thus simulating a unit cell. (MLH)

  9. UNIT, PETROLOGY.

    ERIC Educational Resources Information Center

    Louisiana Arts and Science Center, Baton Rouge.

    THIS TEACHER'S GUIDE FOR A UNIT ON PETROLOGY IS SUITABLE FOR ADAPTATION AT EITHER THE UPPER ELEMENTARY OR THE JUNIOR HIGH SCHOOL LEVELS. THE UNIT BEGINS WITH A STORY THAT INTRODUCES VOLCANIC ACTION AND IGNEOUS ROCK FORMATION. SELECTED CONCEPTS ARE LISTED FOLLOWED BY SUGGESTED ACTIVITIES. A BIBLIOGRAPHY, FILM LIST, VOCABULARY LIST, AND QUESTION AND…

  10. UNIT, ALASKA.

    ERIC Educational Resources Information Center

    Louisiana Arts and Science Center, Baton Rouge.

    THE UNIT DESCRIBED IN THIS BOOKLET DEALS WITH THE GEOGRAPHY OF ALASKA. THE UNIT IS PRESENTED IN OUTLINE FORM. THE FIRST SECTION DEALS PRINCIPALLY WITH THE PHYSICAL GEOGRAPHY OF ALASKA. DISCUSSED ARE (1) THE SIZE, (2) THE MAJOR LAND REGIONS, (3) THE MOUNTAINS, VOLCANOES, GLACIERS, AND RIVERS, (4) THE NATURAL RESOURCES, AND (5) THE CLIMATE. THE…

  11. 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

  12. 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

  13. 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

  14. Unexpected coupling between flow and adsorption in porous media.

    PubMed

    Vanson, Jean-Mathieu; Coudert, François-Xavier; Rotenberg, Benjamin; Levesque, Maximilien; Tardivat, Caroline; Klotz, Michaela; Boutin, Anne

    2015-08-14

    We study the interplay between transport and adsorption in porous systems under a fluid flow, based on a lattice Boltzmann scheme extended to account for adsorption. We performed simulations on well-controlled geometries with slit and grooved pores, investigating the influence of adsorption and flow on dispersion coefficient and adsorbed density. In particular, we present a counterintuitive effect where fluid flow induces heterogeneity in the adsorbate, displacing the adsorption equilibrium towards downstream adsorption sites in grooves. We also present an improvement of the adsorption-extended lattice Boltzmann scheme by introducing the possibility for saturating Langmuir-like adsorption, while earlier work focused on linear adsorption phenomena. We then highlight the impact of this change in situations of high concentration of adsorbate. PMID:26139013

  15. The Calculation of Adsorption Isotherms from Chromatographic Peak Shapes

    ERIC Educational Resources Information Center

    Neumann, M. G.

    1976-01-01

    Discusses the relationship between adsorption isotherms and elution peak shapes in gas chromatography, and describes a laboratory experiment which involves the adsorption of hexane, cyclohexane, and benzene on alumina at different temperatures. (MLH)

  16. IMPACT OF OXYGEN MEDIATED OXIDATIVE COUPLING ON ADSORPTION KINETICS

    EPA Science Inventory

    The presence of molecular oxygen in the test environment promotes oxidative coupling (polymer formation) of phenolic compounds on the surface of granular activated carbon (GAC). Both adsorption equilibria and adsorption kinetics are affected by these chemical reactions. Lack of...

  17. Adsorption of thorium from aqueous solutions by perlite.

    PubMed

    Talip, Z; Eral, M; Hiçsönmez, U

    2009-02-01

    The use of expanded perlite for the adsorption of thorium from aqueous solution by batch technique is presented. The effects of particle size, pH of the solution, initial thorium concentration, shaking time, V/m ratio and temperature were determined. It was found that the adsorption capacity increases by the increase in the pH of the suspensions. The rate of thorium adsorption on expanded perlite was observed to be fast in the first hour of the reaction time. Adsorption isotherms were expressed by Langmuir and Freundlich adsorption models and the adsorption experiments conducted at 30 +/- 1 degrees C showed that the adsorption isotherms correlated well with the Langmuir model. From the adsorption data, thermodynamic parameters such as DeltaG(o), DeltaH(o) and DeltaS(o) were calculated as a function of temperature.

  18. Factors affecting the adsorption of xenon on activated carbon

    SciTech Connect

    Underhill, D.W.; DiCello, D.C.; Scaglia, L.A.; Watson, J.A.

    1986-08-01

    The presence of water vapor was found to interfere strongly with the dynamic adsorption of /sup 133/Xe on coconut-base activated charcoal. The percent loss in the xenon adsorption coefficient was similar to values reported earlier for the adsorption of krypton on humidified charcoal. Attempts to increase the adsorption of xenon by (a) using a petroleum-based adsorbent with an extremely high surface area and (b) by impregnation of the adsorbent with iodine were not successful.

  19. Electrical swing adsorption gas storage and delivery system

    DOEpatents

    Judkins, Roddie R.; Burchell, Timothy D.

    1999-01-01

    Systems and methods for electrical swing natural gas adsorption are described. An apparatus includes a pressure vessel; an electrically conductive gas adsorptive material located within the pressure vessel; and an electric power supply electrically connected to said adsorptive material. The adsorptive material can be a carbon fiber composite molecular sieve (CFCMS). The systems and methods provide advantages in that both a high energy density and a high ratio of delivered to stored gas are provided.

  20. Electrical swing adsorption gas storage and delivery system

    DOEpatents

    Judkins, R.R.; Burchell, T.D.

    1999-06-15

    Systems and methods for electrical swing natural gas adsorption are described. An apparatus includes a pressure vessel; an electrically conductive gas adsorptive material located within the pressure vessel; and an electric power supply electrically connected to said adsorptive material. The adsorptive material can be a carbon fiber composite molecular sieve (CFCMS). The systems and methods provide advantages in that both a high energy density and a high ratio of delivered to stored gas are provided. 5 figs.

  1. Removal of hazardous organic pollutants by biomass adsorption

    SciTech Connect

    Bell, J.P.; Tsezos, M.

    1987-04-01

    This study is aimed at understanding adsorption in biological treatment processes and developing models for predicting the fate of hazardous organic pollutants entering biological wastewater treatment plants. Adsorption of organic chemicals onto two types of inactive microbial biomass was examined. Desorption, temperature effects, and the thermodynamics of the adsorption process were also investigated. Adsorption reversibility demonstrated by pesticides indicate their potential for leaching from land disposal sludges. (Refs. 30).

  2. Photosynthetic units.

    PubMed

    Schmid, G H; Gaffron, H

    1968-08-01

    Leaf tissues of aurea mutants of tobacco and Lespedeza have been shown to have higher photosynthetic capacity per molecule of chlorophyll, a higher saturation intensity, a simpler lamellar structure, and the same quantum yield as their dark green parents. Here we report on the values of photosynthetic units for both types of plants and some algae. The unit has been assumed to be about as uniform and steady in the plant world as the quantum efficiency. The number on which all theoretical discussions have been based so far is 2400 per O(2) evolved or CO(2) reduced. With dark green plants and algae our determinations of units by means of 40 microsec flashes superimposed on a steady rate of background photosynthesis at 900 ergs cm(-2) sec(-1) of red light yielded mostly numbers between 2000 and 2700. However, the photosynthetic unit turned out to be very variable, even in these objects. In aurea mutants the unit was distinctly smaller, averaging 600 chl/CO(2). By choosing the right combination of colors for flash and background light, units as low as 300 chl/CO(2) or 40 chl/e(-) could be measured consistently. We found five well-defined groups of units composed of multiples of its smallest member. These new findings are discussed in terms of structural entities that double or divide under the influence of far-red light.

  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. Fluorocarbon adsorption in hierarchical porous frameworks

    NASA Astrophysics Data System (ADS)

    Motkuri, Radha Kishan; Annapureddy, Harsha V. R.; Vijaykumar, M.; Schaef, H. Todd; Martin, Paul F.; McGrail, B. Peter; Dang, Liem X.; Krishna, Rajamani; Thallapally, Praveen K.

    2014-07-01

    Metal-organic frameworks comprise an important class of solid-state materials and have potential for many emerging applications such as energy storage, separation, catalysis and bio-medical. Here we report the adsorption behaviour of a series of fluorocarbon derivatives on a set of microporous and hierarchical mesoporous frameworks. The microporous frameworks show a saturation uptake capacity for dichlorodifluoromethane of >4 mmol g-1 at a very low relative saturation pressure (P/Po) of 0.02. In contrast, the mesoporous framework shows an exceptionally high uptake capacity reaching >14 mmol g-1 at P/Po of 0.4. Adsorption affinity in terms of mass loading and isosteric heats of adsorption is found to generally correlate with the polarizability and boiling point of the refrigerant, with dichlorodifluoromethane >chlorodifluoromethane >chlorotrifluoromethane >tetrafluoromethane >methane. These results suggest the possibility of exploiting these sorbents for separation of azeotropic mixtures of fluorocarbons and use in eco-friendly fluorocarbon-based adsorption cooling.

  5. Fluorocarbon adsorption in hierarchical porous frameworks.

    PubMed

    Motkuri, Radha Kishan; Annapureddy, Harsha V R; Vijaykumar, M; Schaef, H Todd; Martin, Paul F; McGrail, B Peter; Dang, Liem X; Krishna, Rajamani; Thallapally, Praveen K

    2014-07-09

    Metal-organic frameworks comprise an important class of solid-state materials and have potential for many emerging applications such as energy storage, separation, catalysis and bio-medical. Here we report the adsorption behaviour of a series of fluorocarbon derivatives on a set of microporous and hierarchical mesoporous frameworks. The microporous frameworks show a saturation uptake capacity for dichlorodifluoromethane of >4 mmol g(-1) at a very low relative saturation pressure (P/Po) of 0.02. In contrast, the mesoporous framework shows an exceptionally high uptake capacity reaching >14 mmol g(-1) at P/Po of 0.4. Adsorption affinity in terms of mass loading and isosteric heats of adsorption is found to generally correlate with the polarizability and boiling point of the refrigerant, with dichlorodifluoromethane > chlorodifluoromethane > chlorotrifluoromethane > tetrafluoromethane > methane. These results suggest the possibility of exploiting these sorbents for separation of azeotropic mixtures of fluorocarbons and use in eco-friendly fluorocarbon-based adsorption cooling.

  6. Fluorocarbon adsorption in hierarchical porous frameworks

    SciTech Connect

    Motkuri, RK; Annapureddy, HVR; Vijaykumar, M; Schaef, HT; Martin, PF; McGrail, BP; Dang, LX; Krishna, R; Thallapally, PK

    2014-07-09

    Metal-organic frameworks comprise an important class of solid-state materials and have potential for many emerging applications such as energy storage, separation, catalysis and bio-medical. Here we report the adsorption behaviour of a series of fluorocarbon derivatives on a set of microporous and hierarchical mesoporous frameworks. The microporous frameworks show a saturation uptake capacity for dichlorodifluoromethane of >4 mmol g(-1) at a very low relative saturation pressure (P/P-o) of 0.02. In contrast, the mesoporous framework shows an exceptionally high uptake capacity reaching >14 mmol g(-1) at P/P-o of 0.4. Adsorption affinity in terms of mass loading and isosteric heats of adsorption is found to generally correlate with the polarizability and boiling point of the refrigerant, with dichlorodifluoromethane >chlorodifluoromethane >chlorotrifluoromethane >tetrafluoromethane >methane. These results suggest the possibility of exploiting these sorbents for separation of azeotropic mixtures of fluorocarbons and use in eco-friendly fluorocarbon-based adsorption cooling.

  7. Zinc modulates thrombin adsorption to fibrin

    SciTech Connect

    Hopmeier, P.; Halbmayer, M.; Fischer, M.; Marx, G. )

    1990-05-01

    Human thrombin with high affinity to Sepharose insolubilized fibrin monomers (high-affinity thrombin) was used to investigate the effect of Zn(II) on the thrombin adsorption to fibrin. Results showed that at Zn(II) concentrations exceeding 100 mumols/l, thrombin binding to fibrin was decreased concomitant with the Zn(II) concentration and time; at lower Zn(II) concentrations, thrombin adsorption was enhanced. Experimental results were identical by using 125I-labelled high-affinity alpha-thrombin or by measuring the thrombin activity either by chromogenic substrate or by a clotting time method. In contrast, Ca(II) alone (final conc. 3 mmol/l) or in combination with Zn(II) was not effective. However, at higher Ca(II) concentrations (7.5-15 mmol/l), thrombin adsorption was apparently decreased. Control experiments revealed that Zn(II) had no impact on the clottability of fibrinogen, and that the results of the experiments with Ca(II) were not altered by possible cross-linking of fibrin. We conclude that unlike Ca(II), Zn(II) is highly effective in modulating thrombin adsorption to fibrin.

  8. Modeling adsorption with lattice Boltzmann equation

    PubMed Central

    Guo, Long; Xiao, Lizhi; Shan, Xiaowen; Zhang, Xiaoling

    2016-01-01

    The research of adsorption theory has recently gained renewed attention due to its critical relevance to a number of trending industrial applications, hydrogen storage and shale gas exploration for instance. The existing theoretical foundation, laid mostly in the early twentieth century, was largely based on simple heuristic molecular interaction models and static interaction potential which, although being insightful in illuminating the fundamental mechanisms, are insufficient for computations with realistic adsorbent structure and adsorbate hydrodynamics, both critical for real-life applications. Here we present and validate a novel lattice Boltzmann model incorporating both adsorbate-adsorbate and adsorbate-adsorbent interactions with hydrodynamics which, for the first time, allows adsorption to be computed with real-life details. Connection with the classic Ono-Kondo lattice theory is established and various adsorption isotherms, both within and beyond the IUPAC classification are observed as a pseudo-potential is varied. This new approach not only enables an important physical to be simulated for real-life applications, but also provides an enabling theoretical framework within which the fundamentals of adsorption can be studied. PMID:27256325

  9. Critical analysis of adsorption data statistically

    NASA Astrophysics Data System (ADS)

    Kaushal, Achla; Singh, S. K.

    2016-09-01

    Experimental data can be presented, computed, and critically analysed in a different way using statistics. A variety of statistical tests are used to make decisions about the significance and validity of the experimental data. In the present study, adsorption was carried out to remove zinc ions from contaminated aqueous solution using mango leaf powder. The experimental data was analysed statistically by hypothesis testing applying t test, paired t test and Chi-square test to (a) test the optimum value of the process pH, (b) verify the success of experiment and (c) study the effect of adsorbent dose in zinc ion removal from aqueous solutions. Comparison of calculated and tabulated values of t and χ 2 showed the results in favour of the data collected from the experiment and this has been shown on probability charts. K value for Langmuir isotherm was 0.8582 and m value for Freundlich adsorption isotherm obtained was 0.725, both are <1, indicating favourable isotherms. Karl Pearson's correlation coefficient values for Langmuir and Freundlich adsorption isotherms were obtained as 0.99 and 0.95 respectively, which show higher degree of correlation between the variables. This validates the data obtained for adsorption of zinc ions from the contaminated aqueous solution with the help of mango leaf powder.

  10. Adsorption of Ions at Uncharged Insoluble Monolayers.

    PubMed

    Peshkova, Tatyana V; Minkov, Ivan L; Tsekov, Roumen; Slavchov, Radomir I

    2016-09-01

    A method is proposed for the experimental determination of the adsorption of inorganic electrolytes at a surface covered with insoluble surfactant monolayer. This task is complicated by the fact that the change of the salt concentration alters both chemical potentials of the electrolyte and the surfactant. Our method resolves the question by combining data for the surface pressure versus area of the monolayer at several salt concentrations with data for the equilibrium spreading pressure of crystals of the surfactant (used to fix a standard state). We applied the method to alcohols spread at the surface of concentrated halide solutions. The measured salt adsorption is positive and has nonmonotonic dependence on the area per surfactant molecule. For the liquid expanded film, depending on the concentration, there is one couple of ions adsorbed per each 3-30 surfactant molecules. We analyzed which ion, the positive or the negative, stands closer to the surface, by measuring the effect of NaCl on the Volta potential of the monolayer. The potentiometric data suggest that Na(+) is specifically adsorbed, while Cl(-) remains in the diffuse layer, i.e., the surface is positively charged. The observed reverse Hofmeister series of the adsorptions of NaF, NaCl, and NaBr suggests the same conclusion holds for all these salts. The force that causes the adsorption of Na(+) seems to be the interaction of the ion with the dipole moment of the monolayer. PMID:27529571

  11. Gas separation by adsorption in carbon nanohorns

    NASA Astrophysics Data System (ADS)

    Nekhai, Anton; Gatica, Silvina

    Gas separation by adsorption can be accomplished by three basic physical mechanisms: equilibria, kinetics, and steric effects. Equilibrium mechanisms rely on the strength of attraction between gas molecules and their substrate. For example, CO2 possesses the strongest, attractive interactions with its substrate. As a result, the equilibrium mechanism presents the most plausible strategy to separate carbon dioxide from mixtures. The specification of a sound adsorbent is the key for separation by adsorption. In this paper we investigate carbon nanohrons for selectivity of carbon dioxide over methane. Carbon Nanohorns resemble short, wide, highly defected single-wall nanotubes that end in conical tips (``horns''). In contrast to regular nanotubes that assemble into parallel bundles, nanohorns form spherical aggregates with the nanohorns arranged along radial directions. Using the simulation technique Grand Canonical Monte Carlo (GCMC) we obtained the adsorption isotherms of CH4 and CO2 in a 2D array of carbon nanohorns. We estimated the selectivity based on the IAST approximation. We also study the adsorption of argon and neon and compare with experimental results. We acknowledge support from the Partnership for Reduced Dimension Materials (PRDM), NSF Grant No. DMR1205608.

  12. Modeling adsorption with lattice Boltzmann equation.

    PubMed

    Guo, Long; Xiao, Lizhi; Shan, Xiaowen; Zhang, Xiaoling

    2016-01-01

    The research of adsorption theory has recently gained renewed attention due to its critical relevance to a number of trending industrial applications, hydrogen storage and shale gas exploration for instance. The existing theoretical foundation, laid mostly in the early twentieth century, was largely based on simple heuristic molecular interaction models and static interaction potential which, although being insightful in illuminating the fundamental mechanisms, are insufficient for computations with realistic adsorbent structure and adsorbate hydrodynamics, both critical for real-life applications. Here we present and validate a novel lattice Boltzmann model incorporating both adsorbate-adsorbate and adsorbate-adsorbent interactions with hydrodynamics which, for the first time, allows adsorption to be computed with real-life details. Connection with the classic Ono-Kondo lattice theory is established and various adsorption isotherms, both within and beyond the IUPAC classification are observed as a pseudo-potential is varied. This new approach not only enables an important physical to be simulated for real-life applications, but also provides an enabling theoretical framework within which the fundamentals of adsorption can be studied. PMID:27256325

  13. Modeling the Adsorption of Oxalate onto Montmorillonite.

    PubMed

    Ramos, M Elena; Emiroglu, Caglayan; García, David; Sainz-Díaz, C Ignacio; Huertas, F Javier

    2015-11-01

    In this work, a multiscale modeling of the interaction of oxalate with clay mineral surfaces from macroscale thermodynamic equilibria simulations to atomistic calculations is presented. Previous results from macroscopic adsorption data of oxalate on montmorillonite in 0.01 M KNO3 media at 25 °C within the pH range from 2.5 to 9 have been used to develop a surface complexation model. The experimental adsorption edge data were fitted using the triple-layer model (TLM) with the aid of the FITEQL 4.0 computer program. Surface complexation of oxalate is described by two reactions: >AlOH + Ox(2-) + 2H(+) = >AlOxH + H2O (log K = 14.39) and >AlOH + Ox(2-) + H(+) = >AlOx(-) + H2O (log K = 10.39). The monodentate complex >AlOxH dominated adsorption below pH 4, and the bidentate complex >AlOx(-) was predominant at higher pH values. Both of the proposed inner-sphere oxalate species are qualitatively consistent with previously published diffuse reflectance FTIR spectroscopic results for oxalate on montmorillonite edge surface (Chem. Geol. 2014, 363, 283-292). Atomistic computational studies have been performed to understand the interactions at the molecular level between adsorbates and mineral surface, showing the atomic structures and IR frequency shifts of the adsorption complexes of oxalate with the edge surface of a periodic montmorillonite model. PMID:26444928

  14. Ammonia Production Using Pressure Swing Adsorption

    SciTech Connect

    2009-02-01

    This factsheet describes a research project whose overall objective is to develop and demonstrate a technically feasible and commercially viable system that integrates reaction to produce ammonia along with recovery of the products by adsorption separation methods and significantly decrease the energy requirement in ammonia production.

  15. A computational analysis for amino acid adsorption

    NASA Astrophysics Data System (ADS)

    Owens, Brandon E.; Riemann, Andreas

    2014-06-01

    In this study we have systematically investigated the effects of surface configuration and molecular state for the adsorption of methionine (C5H11NO2S) on a graphite surface using two model force fields, AMBER 3 and MM +. Computational results were compared with experimental results.

  16. ADSORPTION OF ORGANIC CATIONS TO NATURAL MATERIALS

    EPA Science Inventory

    The factors that control the extent of adsorption of amphiphilic organic cations on environmental and pristine surfaces have been studied. The sorbents were kaolinite, montmorillonite, two aquifer materials, and a soil; solutions contained various concentrations of NaCl and CaCl,...

  17. Random sequential adsorption on partially covered surfaces

    NASA Astrophysics Data System (ADS)

    Adamczyk, Zbigniew; Weroński, Paweł

    1998-06-01

    The random sequential adsorption (RSA) approach was used to analyze adsorption of hard spheres at surfaces precovered with smaller sized particles. Numerical simulations were performed to determine the available surface function φl of larger particles for various particle size ratios λ=al/as and surface concentration of smaller particles θs. It was found that the numerical results were in a reasonable agreement with the formula stemming from the scaled particle theory with the modification for the sphere/sphere geometry. Particle adsorption kinetics was also determined in terms of the RSA simulations. By extrapolating the θl vs τ-1/2 dependencies, the jamming concentrations of larger spheres θl∞ were determined as a function of the initial smaller sphere concentration. It was found that θl∞ were considerably reduced by the presence of smaller sized particles, especially for λ≫1. The pair correlation function g of larger particles in the jamming state was also determined, showing more short range ordering (at the same θl) in comparison with monodisperse systems. The theoretical predictions stemming from our calculations suggest that the presence of trace amounts of very small particles may exert a decisive influence on adsorption of larger particles.

  18. Adsorption Kinetics in Nanoscale Porous Coordination Polymers

    SciTech Connect

    Nune, Satish K.; Thallapally, Praveen K.; McGrail, Benard Peter; Annapureddy, Harsha V. R.; Dang, Liem X.; Mei, Donghai; Karri, Naveen; Alvine, Kyle J.; Olszta, Matthew J.; Arey, Bruce W.; Dohnalkova, Alice

    2015-10-07

    Nanoscale porous coordination polymers were synthesized using simple wet chemical method. The effect of various polymer surfactants on colloidal stability and shape selectivity was investigated. Our results suggest that the nanoparticles exhibited significantly improved adsorption kinetics compared to bulk crystals due to decreased diffusion path lengths and preferred crystal plane interaction.

  19. 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

  20. Adsorption of Ions at Uncharged Insoluble Monolayers

    NASA Astrophysics Data System (ADS)

    Peshkova, T. V.; Minkov, I. L.; Tsekov, R.; Slavchov, R. I.

    2016-08-01

    A method is proposed for the experimental determination of the adsorption of inorganic electrolytes at a surface covered with insoluble surfactant monolayer. This task is complicated by the fact that the change of the salt concentration alters both chemical potentials of the electrolyte and the surfactant. Our method resolves the question by combining data for the surface pressure versus area of the monolayer at several salt concentrations with data for the equilibrium spreading pressure of crystals of the surfactant (used to fix a standard state). We applied the method to alcohols spread at the surface of concentrated halide solutions. The measured salt adsorption is positive and has nonmonotonic dependence on the area per surfactant molecule. For the liquid expanded film, depending on the concentration, there is one couple of ions adsorbed per each 3–30 surfactant molecules. We analyzed which ion, the positive or the negative, stands closer to the surface, by measuring the effect of NaCl on the Volta potential of the monolayer. The potentiometric data suggest that Na+ is specifically adsorbed, while Cl– remains in the diffuse layer, i.e., the surface is positively charged. The observed reverse Hofmeister series of the adsorptions of NaF, NaCl, and NaBr suggests the same conclusion holds for all these salts. The force that causes the adsorption of Na+ seems to be the interaction of the ion with the dipole moment of the monolayer.

  1. H2O Adsorption Kinetics on Smectites

    NASA Technical Reports Server (NTRS)

    Zent, Aaron P.; Quinn, Richard C.; Howard, Jeanie; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    The adsorptive equilibration of H2O a with montomorillonite, a smectite clay has been measured. At low temperatures and pressures, equilibration can require many hours, effectively preventing smectites at the martian surface from responding rapidly to diurnal pressure and temperature variations.

  2. 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)

  3. Adsorption of Polymers on Rough Surfaces

    NASA Astrophysics Data System (ADS)

    Venkatakrishnan, Abishek; Kuppa, Vikram

    2014-03-01

    Most of the surfaces encountered in nature display irregularity and self-similarity at certain length scales. Such real surfaces can be mimicked via fractal surfaces using an algorithm that produces random surfaces. The problem of polymer chains adsorbed on smooth surfaces has been well understood whereas adsorption on rough surfaces still remains unclear due to the complexity involved in equilibration and sampling of molecules in such systems. The enthalpic interactions between the monomers and the entropic penalty arising due to adsorption on rough surfaces are significantly different from smooth surfaces. In this study, we investigate the adsorption of freely rotating polymer chains on fractal surfaces by Monte-Carlo molecular simulations. Random fractal surfaces are generated using the diamond-square algorithm for different values of the Hurst parameter. Properties like monomer-surface interaction, density profiles, chain orientation profiles and distribution of adsorbed chain fractions are investigated. We also demonstrate the significant effect of fractal dimension on adsorption of polymers on rough surfaces.

  4. Adsorption features of flavonoids on macroporous adsorption resins functionalized with ionic liquids.

    PubMed

    Lou, Song; Di, Duolong

    2012-10-01

    A series of macroporous adsorption resins (MARs) with novel structures is synthesized via Friedel-Crafts catalyzed reaction. The adsorption kinetics of the synthetic resins with respect to the purification effect is systematically investigated by means of the response surface methodology (RSM). The kinetic data cannot be fitted to the classical model because it does not take multicompartments and desorption rates into consideration. A new multicompartment louver-tide theory is thus developed considering that adsorption is an indefinite dynamic equilibrium process, which can be divided into innumerable ingredients with different desorption rates. This theory produces much better fits to the experimental data and provides a quantitative explanation with multicompartments and adsorption/desorption rates. PMID:22811393

  5. Visualizing Gas Adsorption on Porous Solids: Four Simple, Effective Demonstrations

    ERIC Educational Resources Information Center

    Cheung, Ocean

    2014-01-01

    Gas adsorption on porous solids is a topic that is often discussed in an undergraduate chemistry or chemical engineering course. The idea of porosity and gas adsorption on a porous solid is usually discussed with adsorption isotherms recorded using commercially available equipment. This discussion can be rather abstract and can be difficult for…

  6. Adsorption of halogenated aliphatic contaminants by graphene nanomaterials.

    PubMed

    Zhou, Yang; Apul, Onur Guven; Karanfil, Tanju

    2015-08-01

    In this study, adsorption of ten environmentally halogenated aliphatic synthetic organic compounds (SOCs) by a pristine graphene nanosheet (GNS) and a reduced graphene oxide (rGO) was examined, and their adsorption behaviors were compared with those of a single-walled carbon nanotube (SWCNT) and a granular activated carbon (GAC). In addition, the impacts of background water components (i.e., natural organic matter (NOM), ionic strength (IS) and pH) on the SOC adsorption behavior were investigated. The results indicated HD3000 and SWCNT with higher microporous volumes exhibited higher adsorption capacities for the selected aliphatic SOCs than graphenes, demonstrating microporosity of carbonaceous adsorbents played an important role in the adsorption. Analysis of adsorption isotherms demonstrated that hydrophobic interactions were the dominant contributor to the adsorption of aliphatic SOCs by graphenes. However, π-π electron donor-acceptor and van der Waals interactions are likely the additional mechanisms contributing to the adsorption of aliphatic SOCs on graphenes. Among the three background solution components examined, NOM showed the most influential effect on adsorption of the selected aliphatic SOCs, while pH and ionic strength had a negligible effects. The NOM competition on aliphatic adsorption was less pronounced on graphenes than SWCNT. Overall, in terms of adsorption capacities, graphenes tested in this study did not exhibit a major advantage over SWCNT and GAC for the adsorption of aliphatic SOCs.

  7. 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.

  8. Influence of Soil Solution Salinity on Molybdenum Adsorption by Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Molybdenum (Mo) adsorption on five arid-zone soils from California was investigated as a function of equilibrium solution Mo concentration (0-30 mg L-1), solution pH (4-8), and electrical conductivity (EC = 0.3 or 8 dS m-1). Molybdenum adsorption decreased with increasing pH. An adsorption maximum...

  9. [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

  10. [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.

  11. Dynamic technique for measuring adsorption in a gas chromatograph

    NASA Technical Reports Server (NTRS)

    Deuel, C. L.; Hultgren, N. W.; Mobert, M. L.

    1973-01-01

    Gas-chromatographic procedure, together with mathematical analysis of adsorption isotherm, allows relative surface areas and adsorptive powers for trace concentrations to be determined in a few minutes. Technique may be used to evaluate relative surface areas of different adsorbates, expressed as volume of adsorbent/gram of adsorbate, and to evaluate their relative adsorptive power.

  12. Adsorption of oxygen and 1-butene on magnesium ferrite

    SciTech Connect

    Samuilova, O.K.; Kozlova, M.M.; Yagodovskii, V.D.

    1986-08-01

    The kinetics of the adsorption of oxygen and 1-butene on magnesium ferrite was studied. Conductometry and thermal desorption methods were used to investigate the adsorption of oxygen on magnesium ferrite. Two forms of adsorbed oxygen were found. The formation of these forms affects the kinetics of the adsorption of 1-butene.

  13. Adsorption of DNA onto anionic lipid surfaces.

    PubMed

    Martín-Molina, Alberto; Luque-Caballero, Germán; Faraudo, Jordi; Quesada-Pérez, Manuel; Maldonado-Valderrama, Julia

    2014-04-01

    Currently self-assembled DNA delivery systems composed of DNA multivalent cations and anionic lipids are considered to be promising tools for gene therapy. These systems become an alternative to traditional cationic lipid-DNA complexes because of their low cytotoxicity lipids. However, currently these nonviral gene delivery methods exhibit low transfection efficiencies. This feature is in large part due to the poorly understood DNA complexation mechanisms at the molecular level. It is well-known that the adsorption of DNA onto like charged lipid surfaces requires the presence of multivalent cations that act as bridges between DNA and anionic lipids. Unfortunately, the molecular mechanisms behind such adsorption phenomenon still remain unclear. Accordingly a historical background of experimental evidence related to adsorption and complexation of DNA onto anionic lipid surfaces mediated by different multivalent cations is firstly reviewed. Next, recent experiments aimed to characterise the interfacial adsorption of DNA onto a model anionic phospholipid monolayer mediated by Ca(2+) (including AFM images) are discussed. Afterwards, modelling studies of DNA adsorption onto charged surfaces are summarised before presenting preliminary results obtained from both CG and all-atomic MD computer simulations. Our results allow us to establish the optimal conditions for cation-mediated adsorption of DNA onto negatively charged surfaces. Moreover, atomistic simulations provide an excellent framework to understand the interaction between DNA and anionic lipids in the presence of divalent cations. Accordingly,our simulation results in conjunction go beyond the macroscopic picture in which DNA is stuck to anionic membranes by using multivalent cations that form glue layers between them. Structural aspects of the DNA adsorption and molecular binding between the different charged groups from DNA and lipids in the presence of divalent cations are reported in the last part of the study

  14. Adsorption of ionisable pesticides in soils.

    PubMed

    Kah, M; Brown, C D

    2006-01-01

    Understanding the fate of a pesticide in soil is fundamental to the accurate assessment of its environmental behaviour and vital in ensuring the safe use of new and existing products. Ionisable pesticides comprise a significant proportion of both existing and new active substances registered for use in agriculture worldwide. This group of pesticides includes chemicals that are frequently found in groundwater and surface waters in many different countries. Despite this, approaches to predict the influence of soil properties on the behaviour of ionisable pesticides in soils are poorly developed. Current regulatory assessments frequently default to methods developed for nonionic chemicals, although it is evident that ionisable compounds do not often react like neutral molecules. This review presents the state of knowledge on the adsorption of ionisable pesticides in soils. It first introduces the issues concerning adsorption and the characteristics of this particular kind of chemical. The mechanisms postulated for the adsorption of ionisable pesticides are then described: these are hydrophobic partitioning, ionic exchange, charge transfer, ligand exchange, cation or water bridging, and the formation of bound residues. Relatively little experimental evidence is available, and we are still unable to determine the quantitative contribution of each process in a particular situation. Knowledge is still lacking concerning phenomena occurring at the surfaces of soil particles. Measurements do not allow determination of the operative pH at the surface of soil particles or in microenvironments, and the influence of ionic strength or competition effects is difficult to assess. Subsequently, the review focuses on the influence of soil properties on adsorption and on potential to predict the behaviour of ionisable pesticides in soils. Unlike hydrophobic compounds, adsorption of ionisable pesticides is highly sensitive to variation in pH. This relationship mainly derives from the

  15. Adsorption of hematite nanoparticles onto Caco-2 cells and the cellular impairments: effect of particle size.

    PubMed

    Zhang, Wen; Kalive, Madhavi; Capco, David G; Chen, Yongsheng

    2010-09-01

    The increasing applications of engineered nanomaterials nowadays have elevated the potential of human exposure through various routes including inhalation, skin penetration and digestion. To date there is scarce information on a quantitative description of the interactions between nanoparticles (NPs) and cell surfaces and the detrimental effects from the exposure. The purpose of this work was to study in vitro exposure of Caco-2 cells to hematite (alpha-Fe(2)O(3)) NPs and to determine the particle size effects on the adsorption behaviors. Cellular impairment was also investigated and compared. Hematite NPs were synthesized as part of this study with a discrete size distribution and uniform morphology examined by dynamic light scattering (DLS) and confirmed by transmission electron microscopy (TEM). Caco-2 cells were cultured as a model epithelium to mirror human intestinal cells and used to evaluate the impacts of the exposure to NPs by measuring transepithelial electrical resistance (TEER). Cell surface disruption, localization and translocation of NPs through the cells were analyzed with immunocytochemical staining and confocal microscopy. Results showed that hematite NPs had mean diameters of 26, 53, 76 and 98 nm and were positively charged with minor aggregation in the buffer solution. Adsorption of the four sizes of NPs on cells reached equilibrium within approximately 5 min but adsorption kinetics were found to be size-dependent. The adsorption rates expressed as mg m(-2) min(-1) were greater for large NPs (76 and 98 nm) than those for small NPs (26 and 53 nm). However, adsorption rates, expressed in units of m(-2) min(-1), were much greater for small NPs than large ones. After the adsorption equilibrium was reached, the adsorbed mass of NPs on a unit area of cells was calculated and showed no significant size dependence. Longer exposure time (>3 h) induced adverse cellular effects as indicated by the drop in TEER compared to the control cells without the

  16. Adsorption of hematite nanoparticles onto Caco-2 cells and the cellular impairments: effect of particle size

    NASA Astrophysics Data System (ADS)

    Zhang, Wen; Kalive, Madhavi; Capco, David G.; Chen, Yongsheng

    2010-09-01

    The increasing applications of engineered nanomaterials nowadays have elevated the potential of human exposure through various routes including inhalation, skin penetration and digestion. To date there is scarce information on a quantitative description of the interactions between nanoparticles (NPs) and cell surfaces and the detrimental effects from the exposure. The purpose of this work was to study in vitro exposure of Caco-2 cells to hematite (α-Fe2O3) NPs and to determine the particle size effects on the adsorption behaviors. Cellular impairment was also investigated and compared. Hematite NPs were synthesized as part of this study with a discrete size distribution and uniform morphology examined by dynamic light scattering (DLS) and confirmed by transmission electron microscopy (TEM). Caco-2 cells were cultured as a model epithelium to mirror human intestinal cells and used to evaluate the impacts of the exposure to NPs by measuring transepithelial electrical resistance (TEER). Cell surface disruption, localization and translocation of NPs through the cells were analyzed with immunocytochemical staining and confocal microscopy. Results showed that hematite NPs had mean diameters of 26, 53, 76 and 98 nm and were positively charged with minor aggregation in the buffer solution. Adsorption of the four sizes of NPs on cells reached equilibrium within approximately 5 min but adsorption kinetics were found to be size-dependent. The adsorption rates expressed as mg m - 2 min - 1 were greater for large NPs (76 and 98 nm) than those for small NPs (26 and 53 nm). However, adsorption rates, expressed in units of m - 2 min - 1, were much greater for small NPs than large ones. After the adsorption equilibrium was reached, the adsorbed mass of NPs on a unit area of cells was calculated and showed no significant size dependence. Longer exposure time (>3 h) induced adverse cellular effects as indicated by the drop in TEER compared to the control cells without the exposure

  17. Effect of hypertension on bacteria composition of prostate biopsy in patients with benign prostatic hyperplasia and prostate cancer in PSA grey-zone

    PubMed Central

    NI, XIAOFENG; MENG, HONGZHOU; ZHOU, FENG; YU, HAINING; XIANG, JIANJIAN; SHEN, SHENGRONG

    2016-01-01

    Diagnostic prostate cancer (PC) is difficult to diagnose by prostate biopsy, even in patients with markedly elevated PSA levels. Therefore, we aimed to identify a new, better technique to detect PC in a more consistent manner. A variety of steps were employed to validate this proposed method, including DNA extraction, polymerase chain reaction (PCR) amplification, denaturing gradient gel electrophoresis (DGGE) and DGGE band sequencing. Four transperineal prostate biopsy specimens were obtained from male patients. The patients were under the age of 65 and PSA levels were 4–10 ng/ml. We also investigated the bacteria composition of transperineal prostate biopsy in patients with benign prostatic hyperplasia (BPH) and PC by PCR-DGGE profiling. Sequences from selected bands 2 and 4 both matched with Sphingomonas, which is present in lower amounts in PC without hypertension as compared to PC with hypertension, while there were no particular differences in the BPH group. Specific bacteria from the prostate biopsy tissues provide further confidence in PC diagnosis based on a PCR approach as a diagnostic tool, while hypertension was found to be a disturbing factor that can affect the diagnosis of BPH and PC in grey-zone. PMID:27284421

  18. Expression analysis of the spi gene in the pock-forming plasmid pSA1.1 from Streptomyces azureus and localization of its product during differentiation.

    PubMed

    Doi, Katusmi; Ohyama, Yukiko; Yokoyama, Eiji; Nishiyama, Takashi; Fujino, Yasuhiro; Nagayoshi, Yuko; Ohshima, Toshihisa; Ogata, Seiya

    2012-08-01

    The sporulation inhibitory gene spi in the pock-forming conjugative plasmid pSA1.1 of Streptomyces azureus was introduced into cells via a high or low copy number vector to examine the effect of gene dosage on the growth of Streptomyces lividans TK24 as a host. In transformants carrying a high spi copy number, nutrient mycelial growth was inhibited, as was morphological differentiation from substrate mycelium to aerial mycelium on solid media. The degree of inhibition depended on the spi gene dosage, but the presence of pSA1.1 imp genes, which encode negative repressor proteins for spi, relieved the inhibition. Confocal images of Spi tagged with enhanced green fluorescent protein in cells on solid media revealed that spi expression was initiated at the time of elongation of substrate mycelium, that its expression increased dramatically at septation in aerial hyphae, and that the expression was maximal during prespore formation. Expression of spi covered the whole of the hyphae, and the level of expression at the tip of the hyphae during prespore formation was about sixfold greater than during substrate mycelial growth and threefold greater than during aerial mycelial growth. Thus, localized expression of spi at particular times may inhibit sporulation until triggering imp expression to repress its inhibitory effects.

  19. The effect of high level natural ionizing radiation on expression of PSA, CA19-9 and CEA tumor markers in blood serum of inhabitants of Ramsar, Iran.

    PubMed

    Heidari, Mohammad Hassan; Porghasem, Mohsen; Mirzaei, Nazanin; Mohseni, Jafar Hesam; Heidari, Matine; Azargashb, Eznollah; Movafagh, Abolfazl; Heidari, Reihane; Molouki, Aidin; Larijani, Leila

    2014-02-01

    Since several high level natural radiation areas (HLNRAs) exist on our planet, considerable attention has been drawn to health issues that may develop as the result of visiting or living in such places. City of Ramsar in Iran is an HNLRA, and is a tourist attraction mainly due to its hot spas. However, the growing awareness over its natural radiation sources has prompted widespread scientific investigation at national level. In this study, using an ELISA method, the level of expression of three tumor markers known as carcinoembryonic antigen (CEA), prostate-specific antigen (PSA) and carcino antigen 19-9 (CA19-9) in blood serum of 40 local men of Ramsar (subject group) was investigated and compared to 40 men from the city of Noshahr (control group). Noshahr was previously identified as a normal level natural radiation area (NLNRA) that is some 85 km far from Ramsar. According to statistical analysis, there was a significant difference in the levels of PSA and CA19-9 markers between the two groups (p < 0.001) with those of Ramsar being considerably higher. CEA level did not show any difference. Although some of the volunteers tested positive to the markers, they were in good health as confirmed by the physician. Moreover, the high number of positive markers in Noshahr was considerable. Therefore, future study is needed to further validate this result and to determine the level of positivity to tumor markers in both cities.

  20. [A comparative study of the role of the yadA, invA, and psaA genes in the pathogenicity of Yersinia pseudotuberculosis].

    PubMed

    Karataev, G I; Markov, A R; Siniashina, L N; Miller, G G; Klitsunova, N V; Titova, I V; Semin, E G; Goncharova, N I; Pokrovskaia, M S; Amelina, I P; Amoako, K; Smirnov, G B

    2008-01-01

    The roles of yadA, invA, and psaA genes introduced into the genetic background of the Y. pseudotuberculosis strain possessing the large p VM82 plasmid in virulence and invasion capacity were studied. Isogenic single mutants as well as double and multiple mutants of these genes were constructed and used. LD50 was used as a measure of virulence and the estimation of the ability to invade mammalian cells and the effect of infection on the weight changes of infected mice were used as additional indicators of pathogenicity. It was shown that the YadA had a major effect on the bacterial virulence when compared with the effects of PsaA and InvA. InvA appears to mediate the main pathway of the cellular invasion. YadA is responsible for the weight loss after infection of mice with sublethal doses of Y. pseudotuberculosis. The effects of YadA on virulence and of InvA on bacterial invasion were independent of the expression of the other genes studied. To our knowledge, this study showed for the first time the direct involvement of YadA in the virulence of Y. pseudotuberculosis in mice. Further pathomorphological studies are required to reveal the differences in the pathogenesis of pseudotuberculosis caused by yadA mutants or yadA+ bacteria of Y. pseudotuberculosis.

  1. Antibody Binding Specificity for Kappa (Vκ) Light Chain-containing Human (IgM) Antibodies: Polysialic Acid (PSA) Attached to NCAM as a Case Study

    PubMed Central

    Watzlawik, Jens O.; Kahoud, Robert J.; Wootla, Bharath; Painter, Meghan M.; Warrington, Arthur E.; Carey, William A.; Rodriguez, Moses

    2016-01-01

    Antibodies of the IgM isotype are often neglected as potential therapeutics in human trials, animal models of human diseases as well as detecting agents in standard laboratory techniques. In contrast, several human IgMs demonstrated proof of efficacy in cancer models and models of CNS disorders including multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). Reasons for their lack of consideration include difficulties to express, purify and stabilize IgM antibodies, challenge to identify (non-protein) antigens, low affinity binding and fundamental knowledge gaps in carbohydrate and lipid research. This manuscript uses HIgM12 as an example to provide a detailed protocol to detect antigens by Western blotting, immunoprecipitations and immunocytochemistry. HIgM12 targets polysialic acid (PSA) attached to the neural cell adhesion molecule (NCAM). Early postnatal mouse brain tissue from wild type (WT) and NCAM knockout (KO) mice lacking the three major central nervous system (CNS) splice variants NCAM180, 140 and 120 was used to evaluate the importance of NCAM for binding to HIgM12. Further enzymatic digestion of CNS tissue and cultured CNS cells using endoneuraminidases led us to identify PSA as the specific binding epitope for HIgM12. PMID:27404858

  2. How specific halide adsorption varies hydrophobic interactions.

    PubMed

    Stock, Philipp; Müller, Melanie; Utzig, Thomas; Valtiner, Markus

    2016-03-11

    Hydrophobic interactions (HI) are driven by the water structure around hydrophobes in aqueous electrolytes. How water structures at hydrophobic interfaces and how this influences the HI was subject to numerous studies. However, the effect of specific ion adsorption on HI and hydrophobic interfaces remains largely unexplored or controversial. Here, the authors utilized atomic force microscopy force spectroscopy at well-defined nanoscopic hydrophobic interfaces to experimentally address how specific ion adsorption of halide ions as well as NH4 (+), Cs(+), and Na(+) cations alters interaction forces across hydrophobic interfaces. Our data demonstrate that iodide adsorption at hydrophobic interfaces profoundly varies the hydrophobic interaction potential. A long-range and strong hydration repulsion at distances D > 3 nm, is followed by an instability which could be explained by a subsequent rapid ejection of adsorbed iodides from approaching hydrophobic interfaces. In addition, the authors find only a weakly pronounced influence of bromide, and as expected no influence of chloride. Also, all tested cations do not have any significant influence on HI. Complementary, x-ray photoelectron spectroscopy and quartz-crystal-microbalance with dissipation monitoring showed a clear adsorption of large halide ions (Br(-)/I(-)) onto hydrophobic self-assembled monolayers (SAMs). Interestingly, iodide can even lead to a full disintegration of SAMs due to specific and strong interactions of iodide with gold. Our data suggest that hydrophobic surfaces are not intrinsically charged negatively by hydroxide adsorption, as it was generally believed. Hydrophobic surfaces rather interact strongly with negatively charged large halide ions, leading to a surface charging and significant variation of interaction forces.

  3. Cryogels: morphological, structural and adsorption characterisation.

    PubMed

    Gun'ko, Vladimir M; Savina, Irina N; Mikhalovsky, Sergey V

    2013-01-01

    Experimental results on polymer, protein, and composite cryogels and data treatment methods used for morphological, textural, structural, adsorption and diffusion characterisation of the materials are analysed and compared. Treatment of microscopic images with specific software gives quantitative structural information on both native cryogels and freeze-dried materials that is useful to analyse the drying effects on their structure. A combination of cryoporometry, relaxometry, thermoporometry, small angle X-ray scattering (SAXS), equilibrium and kinetic adsorption of low and high-molecular weight compounds, diffusion breakthrough of macromolecules within macroporous cryogel membranes, studying interactions of cells with cryogels provides a consistent and comprehensive picture of textural, structural and adsorption properties of a variety of cryogels. This analysis allows us to establish certain regularities in the cryogel properties related to narrow (diameter 0.4100 μm) with boundary sizes within modified life science pore classification. Particular attention is paid to water bound in cryogels in native superhydrated or freeze-dried states. At least, five states of water - free unbound, weakly bound (changes in the Gibbs free energy-ΔG<0.5-0.8 kJ/mol) and strongly bound (-ΔG>0.8 kJ/mol), and weakly associated (chemical shift of the proton resonance δ(H)=1-2 ppm) and strongly associated (δ(H)=3-6 ppm) waters can be distinguished in hydrated cryogels using (1)H NMR, DSC, TSDC, TG and other methods. Different software for image treatment or developed to analyse the data obtained with the adsorption, diffusion, SAXS, cryoporometry and thermoporometry methods and based on regularisation algorithms is analysed and used for the quantitative morphological, structural and adsorption characterisation of individual and composite cryogels, including polymers

  4. Adsorption of heavy metal ions by hierarchically structured magnetite-carbonaceous spheres.

    PubMed

    Gong, Jingming; Wang, Xiaoqing; Shao, Xiulan; Yuan, Shuang; Yang, Chenlin; Hu, Xianluo

    2012-11-15

    Magnetically driven separation technology has received considerable attention in recent decade for its great potential application. In this work, hierarchically structured magnetite-carbonaceous microspheres (Fe(3)O(4)-C MSs) have been synthesized for the adsorption of heavy metal ions from aqueous solution. Each sphere contains numerous unique rattle-type structured magnetic particles, realizing the integration of rattle-type building unit into microspheres. The as-prepared composites with high BET surface area, hierarchical as well as mesoporous structures, exhibit an excellent adsorption capacity for heavy metal ions and a convenient separation procedure with the help of an external magnet. It was found that the maximum adsorption capacity of the composite toward Pb(2+) was ∼126mgg(-1), displaying a high efficiency for the removal of heavy metal ions. The Freundlich adsorption isotherm was applicable to describe the removal processes. Kinetics of the Pb(2+) removal was found to follow pseudo-second-order rate equation. The as-prepared composite of Fe(3)O(4)-C MSs as well as Pb(2+)-adsorbed composite were carefully examined by scanning electron microscopy (SEM), Zeta potential measurements, Fourier transform infrared spectroscopy (FT-IR), nitrogen sorption measurements, and X-ray photoelectron spectroscopy (XPS). Based on the characterization results, a possible mechanism of Pb(2+) removal with the composite of Fe(3)O(4)-C MSs was proposed.

  5. Phosphate adsorption on aluminum-coordinated functionalized macroporous–mesoporous silica: Surface structure and adsorption behavior

    SciTech Connect

    Huang, Weiya; Li, Dan; Zhu, Yi; Xu, Kai; Li, Jianqiang; Han, Boping; Zhang, Yuanming

    2013-12-15

    Graphical abstract: - Highlights: • Al-coordinated functionalized macroporous–mesoporous silica for phosphate removal. • It had the maximum adsorption capacity of 23.59 mg P/g. • Over 95% of the final adsorption capacity reached in the first 1 min. - Abstract: In this study, Al(III)-coordinated diamino-functionalized macroporous–mesoporous silica was synthesized and characterized by X-ray diffraction, N{sub 2} adsorption–desorption, Fourier transform infrared spectroscopy, scanning and transmission electron microscopy. Because of well-defined and interconnecting macroporous–mesoporous networks, the resulting adsorbent (MM-SBA) exhibited a significantly better phosphate adsorption performance and faster removal rate, as compared with the mesoporous adsorbent (M-SBA). Based on the Freundlich and Langmuir models, the phosphate adsorption capacity and the maximum adsorption capacity of MM-SBA were 7.99 mg P/g and 23.59 mg P/g, respectively. In the kinetic study of MM-SBA, over 95% of its final adsorption capacity reached in the first 1 min; whereas that of M-SBA was less than 79%.

  6. 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.

  7. Patients with Persistently Elevated PSA and Negative Results of TRUS-Biopsy: Does 6-Month Treatment with Dutasteride can Indicate Candidates for Re-Biopsy. What is the Best of Saturation Schemes: Transrectal or Transperineal Approach?

    PubMed

    Kravchick, Sergey; Lobik, Leonid; Cytron, Shmuel; Kravchenko, Yakov; Dor, David Ben; Peled, Ronit

    2015-09-01

    To identify patients who actually need a re - biopsy, based on alterations in PSA readings after 6-month treatment with Dutasteride. We also sought to bring out the most beneficial re-biopsy scheme. We have reviewed the records of patients with persistently elevated PSA and at least one set of TRUS biopsies. Patients who were treated with alpha -blockers/Dutasteride combination were considered as the study group, while patients in control received alpha-blockers alone. Patients in both groups underwent re-biopsy 6 months later. The two protocols of re-biopsies were used at that time: 20-24 cores saturation transrectal (ST)) and ≥ 40 cores saturation transperineal template-guided (STT) biopsies. One hundred thirty-three patients were included in this study. In 86.7 % of the patients in the study group mean PSA decreased from 7.4 ± 2.69 to 4.037 ± 1.53 (p-0.001). The overall cancer detection rate was 29 % (n-39: 19 v/s 20, control and study groups, respectively). In the study group PSA decreased to 26.73 ± 11.26 % in patients with cancer, compared with 40.54 ± 13.3 % in patients without. It must be emphasized that STT-biopsies detected significantly more cancers (38.46 v/s 20.59 %, p- 0.005). Mean cores number got to 21 ± 2.45 and 45 ± 5.65 in ST and STT biopsies, respectively. Six-month treatment with Dutasteride decreases PSA readings in 86.7 % of the patients. A PSA decline of less than 40% (cutoff) should be considered as an indicator for re-biopsy. Transperineal template-guided biopsies had a higher cancer detection rate. PMID:25753982

  8. Precise control of surface electrostatic forces on polymer brush layers with opposite charges for resistance to protein adsorption.

    PubMed

    Sakata, Sho; Inoue, Yuuki; Ishihara, Kazuhiko

    2016-10-01

    Various molecular interaction forces are generated during protein adsorption process on material surfaces. Thus, it is necessary to control them to suppress protein adsorption and the subsequent cell and tissue responses. A series of binary copolymer brush layers were prepared via surface-initiated atom transfer radical polymerization, by mixing the cationic monomer unit and anionic monomer unit randomly in various ratios. Surface characterization revealed that the constructed copolymer brush layers exhibited an uniform super-hydrophilic nature and different surface potentials. The strength of the electrostatic interaction forces operating on these mixed-charge copolymer brush surfaces was evaluated quantitatively using force-versus-distance (f-d) curve measurements by atomic force microscopy (AFM) and probes modified by negatively charged carboxyl groups or positively charged amino groups. The electrostatic interaction forces were determined based on the charge ratios of the copolymer brush layers. Notably, the surface containing equivalent cationic/anionic monomer units hardly interacted with both the charged groups. Furthermore, the protein adsorption force and the protein adsorption mass on these surfaces were examined by AFM f-d curve measurement and surface plasmon resonance measurement, respectively. To clarify the influence of the electrostatic interaction on the protein adsorption behavior on the surface, three kinds of proteins having negative, positive, and relatively neutral net charges under physiological conditions were used in this study. We quantitatively demonstrated that the amount of adsorbed proteins on the surfaces would have a strong correlation with the strength of surface-protein interaction forces, and that the strength of surface-protein interaction forces would be determined from the combination between the properties of the electrostatic interaction forces on the surfaces and the charge properties of the proteins. Especially, the

  9. Adsorption of basic dyes from aqueous solution onto pumice powder.

    PubMed

    Akbal, Feryal

    2005-06-15

    The adsorption of methylene blue and crystal violet on pumice powder samples of varying compositions was investigated using a batch adsorption technique. The effects of various experimental parameters, such as adsorbent dosage, initial dye concentration, and contact time, were also investigated. The extent of dye removal increased with decreased initial concentration of the dye and also increased with increased contact time and amount of adsorbent used. Adsorption data were modeled using the Freundlich adsorption isotherm. The adsorption kinetic of methylene blue and crystal violet could be described by the pseudo-second-order reaction model.

  10. Adsorption-desorption behavior of thiram onto humic acid.

    PubMed

    Filipe, O M S; Vidal, M M; Duarte, A C; Santos, E B H

    2009-06-10

    The adsorption/desorption behavior of pure thiram (Thi-P) and formulated thiram (Thi-F) onto commercial humic acids (HA) was studied using a batch equilibration procedure. Results of adsorption kinetic experiments showed that thiram adsorption is a fast process since 85% of the equilibrium concentration is reached within two hours. Experimental K(D) values between 0.110 to 0.210 L g(-1) were obtained for the adsorption of both Thi-P and Thi-F onto HA, suggesting that thiram is strongly sorbed by humic acids. In general, for both Thi-P and Thi-F, the lower the initial thiram concentration, the stronger is its adsorption (higher K(D) and percentage adsorption values). The adsorption isotherms were found to match the BET model. The results show that thiram adsorption onto condensed humic acids cannot be explained only in terms of specific interactions, such as those identified in studies of adsorption of thiram with humic acids in solution. The comparison of sorption and desorption results allowed the observation of hysteresis phenomena. Desorption K(D) values were consistently higher than those for adsorption at the same equilibrium concentration. Hysteresis was lower for the formulated thiram suggesting that adsorption is more reversible in the presence of the formulation components turning the pesticide more susceptible to be leached.

  11. Ibuprofen adsorption in four agricultural volcanic soils.

    PubMed

    Estevez, Esmeralda; Hernandez-Moreno, Jose Manuel; Fernandez-Vera, Juan Ramon; Palacios-Diaz, Maria Pino

    2014-01-15

    Ibuprofen (IB) is a high environmental risk drug and one of the most frequently prescribed in human medicine. Recently, IB has been detected in Gran Canaria in reclaimed water for irrigation and in groundwater. Adsorption was studied in four volcanic soils from three islands of the Canarian Archipelago. Once the biodegradation process has been excluded from the experimental conditions, a batch method was applied using initial concentrations of 1-5-10-20-50-100-200 mg L(-1) and two soil/water ratios (w/V): 1:5 (OECD, 2000) and 1:1. Non-linear and linearized Langmuir and Freundlich equations were well fitted. The wide IB range tested in our batch studies allowed us to measure experimental adsorption values close to the maximum adsorption capacity (S(max)) as estimated by Langmuir, making it possible thereby to validate the use of the Langmuir equation when there is a burst of contamination at high concentration. The distribution coefficient (Kd), S(max) and Retardation Factor (RF) varied from 0.04 to 0.5 kg L(-1), 4-200 mgk g(-1) and 1.2-1.9, respectively. The lowest S(max) and Kd values were found for the 1:1S/W ratio whereas most batch studies employ 1:5S/W ratios, thus obtaining higher adsorption parameters than when considering field conditions (1:1). Despite the high anion retention of andic soils, similar Kd and RF to those reported for other soils were obtained in 1:5, while high S(max) was found. Our results demonstrate that IB adsorption in volcanic areas responds not only to the soil properties commonly cited in adsorption studies, but also depends on andic properties, sorbent concentration and Dissolved Organic Carbon, the higher values of which are related to the lower Kd and S(max). The low RF and low detection frequency of the IB in groundwater suggests that a) reclaimed water irrigation is not the main source of IB, and b) the existence of some uncontrolled water disposal points in the zone.

  12. Carbon dioxide adsorption in Brazilian coals

    SciTech Connect

    Jose Luciano Soares; Andre L.B. Oberziner; Humberto J. Jose; Alirio E. Rodrigues; Regina F.P.M. Moreira

    2007-01-15

    Carbon dioxide (CO{sub 2}) is one of the most important greenhouse gases. In the period between 1980 and 1998, CO{sub 2} emissions increased more than 21% and projections suggest that the emissions will continue to increase globally by 2.2% between 2000 and 2020 and 3.3% in the developed countries. The sequestration of CO{sub 2} in deep unminable coal beds is one of the more promising of several methods of geological sequestration that are currently being investigated. CO{sub 2} can adsorb onto coal, and there are several studies demonstrating that CO{sub 2} dissolves in coals and swells them. At very low pressures (P {lt} 1 bar), CO{sub 2} dissolution does not seem to be a problem; however, high pressures are necessary for CO{sub 2} sequestration (P {gt} 50 bar). In this study, we evaluated the kinetics and equilibrium of sorption of CO{sub 2} on Brazilian coals at low pressures. The adsorption equilibrium isotherm at room temperature (30{sup o}C) was measured through the static method. The results showed that the Freundlich model or the Langmuir model is suitable to describe the equilibrium experimental results. The CO{sub 2} adsorption capacity of Brazilian coals are in the range of 0.089-0.186 mmol CO{sub 2}/g, which are typical values for coals with high ash content. The dynamics of adsorption in a fixed-bed column that contains granular coal (particle sizes of 0.8, 2.4, and 4.8 mm) showed that the adsorption rate is fast and a mathematical model was developed to describe the CO{sub 2} dynamics of the adsorption in a fixed-bed column. The linear driving force (LDF) was used to describe the rate of adsorption and the mass-transfer constants of the LDF model (K{sub s}) are in the range of 1.0-2.0 min{sup -1}. 29 refs., 5 figs., 3 tabs.

  13. Adsorption of catechol from aqueous solution by aminated hypercrosslinked polymers.

    PubMed

    Sun, Yue; Li, Xiao-Tao; Xu, Chao; Chen, Jin-Long; Li, Ai-Min; Zhang, Quan-Xing

    2005-01-01

    Adsorption of catechol from aqueous solution with the hypercrosslinked polymeric adsorbent NDA-100 and its derivatives AH-1, AH-2 and AH-3 aminated by dimethylamine, the commercial resin Amberlite XAD-4 and weakly basic anion exchanger resin D301 was compared. It was found that the aminated hypercrosslinked resins had the highest adsorption capacities among the tested polymers. The empirical Freundlich equation was successfully employed to describe the adsorption process. Specific surface area and micropore structure of the adsorbent, in company with tertiary amino groups on matrix affected the adsorption performance towards catechol. In addition, thermodynamic study was carried out to interpret the adsorption mechanism. Kinetic study testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate and increase the adsorption apparent activation energy.

  14. 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.

  15. 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