Science.gov

Sample records for adsorbent dosage contact

  1. Contact and friction of nanoasperities: effects of adsorbed monolayers.

    PubMed

    Cheng, Shengfeng; Luan, Binquan; Robbins, Mark O

    2010-01-01

    Molecular dynamics simulations are used to study contact between a rigid, nonadhesive, and spherical tip with radius of order 30 nm and a flat elastic substrate covered with a fluid monolayer of adsorbed chain molecules. Previous studies of bare surfaces showed that the atomic scale deviations from a sphere that are present on any tip constructed from discrete atoms lead to significant deviations from continuum theory and dramatic variability in friction forces. Introducing an adsorbed monolayer leads to larger deviations from continuum theory but decreases the variations between tips with different atomic structure. Although the film is fluid, it remains in the contact and behaves qualitatively like a thin elastic coating except for certain tips at high loads. Measures of the contact area based on the moments or outer limits of the pressure distribution and on counting contacting atoms are compared. The number of tip atoms making contact during a time interval Deltat grows as a power of Deltat when the film is present and as the logarithm of Deltat for bare surfaces. Friction is measured by displacing the tip at a constant velocity or pulling the tip with a spring. Both static and kinetic friction rise linearly with load at small loads. Transitions in the state of the film lead to nonlinear behavior at large loads. The friction is less clearly correlated with contact area than load. PMID:20365427

  2. Product development studies on surface-adsorbed nanoemulsion of olmesartan medoxomil as a capsular dosage form.

    PubMed

    Singh, Sumita; Pathak, Kamla; Bali, Vikas

    2012-12-01

    The present study aimed at development of capsular dosage form of surface-adsorbed nanoemulsion (NE) of olmesartan medoxomil (OLM) so as to overcome the limitations associated with handling of liquid NEs without affecting their pharmaceutical efficacy. Selection of oil, surfactant, and cosurfactant for construction of pseudoternary phase diagrams was made on the basis of solubility of drug in these excipients. Rationally selected NE formulations were evaluated for percentage transmittance, viscosity, refractive index, globule size, zeta potential, and polydispersity index (PDI). Formulation (F3) comprising of Capmul MCM® (10% v/v), Tween 80® (11.25% v/v), polyethylene glycol 400 (3.75% v/v), and double-distilled water (75% v/v) displayed highest percentage cumulative drug release (%CDR; 96.69 ± 1.841), least globule size (17.51 ± 5.87 nm), low PDI (0.203 ± 0.032), high zeta potential (-58.93 ± 0.98 mV), and hence was selected as the optimized formulation. F3 was adsorbed over colloidal silicon dioxide (2 ml/400 mg) to produce free-flowing solid surface-adsorbed NE that presented a ready-to-fill capsule composition. Conversion of NE to surface-adsorbed NE and its reconstitution to NE did not affect the in vitro release profile of OLM as the similarity factor with respect to NE was found to be 66% and 73% respectively. The %CDR after 12 h for optimized NE, surface-adsorbed NE, and reconstituted NE was found to be 96.69 ± 0.54, 96.07 ± 1.76, and 94.78 ± 1.57, respectively (p > 0.05). The present study established capsulated surface-adsorbed NE as a viable delivery system with the potential to overcome the handling limitations of NE. PMID:22965661

  3. Contact line of adsorbed colloid-polymer droplets in theory and experiment.

    PubMed

    Koning, Jesper; Hennequin, Yves; Bonn, Daniel; Indekeu, Joseph O

    2016-05-01

    The contact line between the colloid-rich bulk liquid and an adsorbed thin film in colloid-polymer mixtures (CPM) is studied by means of an interface displacement model. The interface displacement profiles are compared to laser scanning confocal microscopy (LSCM) images. The mixtures consist of poly(methylmetacrylate) (PMMA) colloids and polystyrene (PS) polymers with polymer-to-colloid size ratio q = 1.18. Based on the experimental parameters, the theoretical model predicts a contact angle for colloid-rich liquid droplets adsorbed on glass of θ∞ = 59°, assuming a contact line with infinite radius, R = ∞. When a contact-line curvature correction and a correction for the protein-limit character of the CPM are taken into account, a modest shift is obtained. The refined theory predicts θ≈ 56°. The contact angle determined visually from the LSCM images is θ≈ 30°. The model predicts a three-phase contact-line tension of τ = -1.2 × 10(-12) N (uncorrected) and τ = -2.3 × 10(-13) N (with protein-limit correction), which is physically sound both in sign and magnitude. The line tension influences the contact angle to a small extent due to the contact line curvature. The predicted width of the transition zone between the thin film and the droplet is about 2 μm. The effect of gravity is noticeable as a deformation near the middle of the droplet. PMID:27029605

  4. Influence of adsorbed fluids on the rolling contact deformation of MgO single crystals

    NASA Technical Reports Server (NTRS)

    Dufrane, K. F.

    1977-01-01

    Basic phenomena associated with rolling contact deformation were studied using MgO as a model bearing material. A hardened steel ball was rolled on MgO single crystals in slow-speed reciprocating motion and in high-speed circular motion. The resulting deformation was studied by dislocation etch-pit techniques. The presence of adsorbed fluids, such as silicone oil, white mineral oil, and toluene, with slow-speed sliding caused a dramatic change in slip mode and premature surface spalling compared with similar experiments in air or under water. In contrast, dimethyl formamide inhibited these slip processes. The results are consistent with the dependence of dislocation mobility on adsorbed species. High-speed hydrodynamic rolling with mineral oil lubrication produced a different slip phenomena entirely from the slow-speed rolling. The slip bands resembled those produced in tensile tests, and all slip apparently initiated at subsurface sites.

  5. Dosage of amyloid precursor protein affects axonal contact guidance in Down syndrome.

    PubMed

    Sosa, Lucas J; Postma, Nienke L; Estrada-Bernal, Adriana; Hanna, M; Guo, R; Busciglio, Jorge; Pfenninger, Karl H

    2014-01-01

    Amyloid precursor protein (APP), encoded on Hsa21, functions as a cell adhesion molecule (CAM) in axonal growth cones (GCs) of the developing brain. We show here that axonal GCs of human fetal Down syndrome (DS) neurons (and of a DS mouse model) overexpress APP protein relative to euploid controls. We investigated whether DS neurons generate an abnormal, APP-dependent GC phenotype in vitro. On laminin, which binds APP and β1 integrins (Itgb1), DS neurons formed enlarged and faster-advancing GCs compared to controls. On peptide matrices that bind APP only, but not on those binding exclusively Itgb1 or L1CAM, DS GCs were significantly enlarged (2.0-fold), formed increased close adhesions (1.8-fold), and advanced faster (1.4-fold). In assays involving alternating stripes of monospecific matrices, human control GCs exhibited no preference for any of the substrates, whereas DS GCs preferred the APP-binding matrix (cross-over decreased significantly from 48.2 to 27.2%). Reducing APP expression in DS GCs with siRNA normalized most measures of the phenotype, including substrate choice. These experiments show that human DS neurons exhibit an APP-dependent, abnormal GC phenotype characterized by increased adhesion and altered contact guidance. The results suggest that APP overexpression may perturb axonal pathfinding and circuit formation in developing DS brain. PMID:24036883

  6. Polarizabilities of Adsorbed and Assembled Molecules: Measuring the Conductance through Buried Contacts

    PubMed Central

    2010-01-01

    We have measured the polarizabilities of four families of molecules adsorbed to Au{111} surfaces, with structures ranging from fully saturated to fully conjugated, including single-molecule switches. Measured polarizabilities increase with increasing length and conjugation in the adsorbed molecules and are consistent with theoretical calculations. For single-molecule switches, the polarizability reflects the difference in substrate−molecule electronic coupling in the ON and OFF conductance states. Calculations suggest that the switch between the two conductance states is correlated with an oxidation state change in a nitro functional group in the switch molecules. PMID:21077677

  7. Theoretical study of the three-phase contact line and its tension in adsorbed colloid-polymer mixtures.

    PubMed

    Vandecan, Yves; Indekeu, Joseph O

    2008-03-14

    We perform a theoretical study of the three-phase contact line and the line tension in an adsorbed colloid-polymer mixture near a first-order wetting transition, employing an interface displacement model. We use a simple free-energy functional to describe a colloid-polymer mixture near a hard wall. The bulk phase behavior and the substrate-adsorbate interaction are modeled by the free-volume theory for ideal polymers. The large size of the colloidal particles and the suppression of the van der Waals interaction by optical matching of colloid and solvent justify the planar hard wall model for the substrate. Following the Fisher-Jin scheme, we derive from the free-energy functional an interface potential V(l) for these mixtures. For a particle diameter of 10-100 nm, the calculations indicate a line tension tau approximately 10(-12)-10(-13) N at room temperature. In view of the ultralow interfacial tension in colloid-polymer mixtures, gamma approximately 10(-7) Nm, this leads to a rather large characteristic length scale taugamma in the micrometer range for the three-phase contact zone width. In contrast with molecular fluids, this zone could be studied directly with optical techniques such as confocal scanning laser microscopy. PMID:18345923

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

    PubMed

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

    2015-10-20

    Interparticle forces govern the mechanical behavior of granular matter and direct the hierarchical assembling of nanoparticles into supramolecular structures. Understanding how these forces change under different ambient conditions would directly benefit industrial-scale nanoparticle processing units such as filtering and fluidization. Here we rationalize and quantify the contributions of dispersion, capillary, and solvation forces between hydrophilic TiO2 nanoparticles with sub-10 nm diameter and show that the humidity dependence of the interparticle forces is governed by a delicate interplay between the structure of adsorbed water layers and the surface roughness. All-atom molecular dynamics modeling supported by force-spectroscopy experiments reveals an unexpected decrease in the contact forces at increasing humidity for nearly spherical particles, while the forces between rough particles are insensitive to strong humidity changes. Our results also frame the limits of applicability of discrete solvation and continuum capillary theories in a regime where interparticle forces are dominated by the molecular nature of surface adsorbates. PMID:26414448

  9. The Influence of Contact Adsorbed Ions on the Photoelectrochemical Behaviour of α-HgS

    NASA Astrophysics Data System (ADS)

    Repenning, D.; Schumawcher, R.; Schindler, R. N.

    1982-04-01

    Results are reported to describe the influence of additives on the photoelectrochemical properties of the liquid junction α-HgS/electrolyte. The semiconductor electrodes were prepared by sublimation of α-HgS on Au substrates. The electrolyte was modified by additives such as Cl-, Br-, J-, and CN- ions. It was found that these anions play an important role in determining the flat band Vfb and the transition potential Vtr. Generally, both the nature and the concentration of the additives affect Vfb and Vtr.The results are interpreted in terms of contact adsorption of the used anions. It is further indicated that the adsorptive properties can be correlated to a possible chemical reaction of mercury cations with halide anions to form insoluble layers at the surface.

  10. Adsorption of high ammonium nitrogen from wastewater using a novel ceramic adsorbent and the evaluation of the ammonium-adsorbed-ceramic as fertilizer.

    PubMed

    Zhao, Yingxin; Yang, Yingnan; Yang, Shengjiong; Wang, Qinghong; Feng, Chuanping; Zhang, Zhenya

    2013-03-01

    A novel ceramic adsorbent was developed to adsorb ammonium from high concentration ammonium contaminated wastewater. Typical gardening cultivation mediums in Japan-Kanuma clay and Akadama clay were used to synthesize the ceramic adsorbent. Static batch experiments were conducted to investigate the effect of various parameters such as contact time, initial ammonium concentration, adsorbent dosage, and competing cations during the ammonium adsorption process. The results revealed that the Freundlich isotherm model fitted better with the adsorption process than the Langmuir model, and the adsorption process was well described by pseudo-second-order kinetic model. The maximum nitrogen adsorption capacity of the ceramic adsorbent was 75.5 mg g(-1) at an initial NH(4)(+)-N concentration of 10,000 mg L(-1), dosage of 20 g L(-1), and contact time of 480 min. Results demonstrated that the low-cost ceramic adsorbent directly used as nitrogen fertilizer was feasible for its high ammonium nitrogen content, nontoxic effect on the environment and excellent soil properties. PMID:23153680

  11. Suppression of alveolar macrophage membrane receptor-mediated phagocytosis by model and actual particle-adsorbate complexes. Initial contact with the alveolar macrophage membrane.

    PubMed Central

    Jakab, G J; Risby, T H; Sehnert, S S; Hmieleski, R R; Farrington, J E

    1990-01-01

    Alveolar macrophages were treated with carbon blacks and adsorbates in order to evaluate the biologic effect of adsorbate, adsorbent and adsorbate-adsorbent complexes. Their capacity to phagocytize a subsequent challenge via the Fc-membrane receptor was quantified. Phagocytosis was suppressed in a dose-related manner with increasing concentrations of both carbon blacks and adsorbates. Carbon black N339 covered with 0.5 monolayers of the adsorbates suppressed phagocytosis more than N339 without the adsorbates. Increasing the adsorbate acrolein coverage from 0.5 to greater than 2.0 monolayers suppressed phagocytosis in a dose-related manner. Finally, samples of diesel particulate matter collected from an engine operated on a pure hydrocarbon fuel with various oxidizers, air (PSU #1) and an oxidizer free of nitrogen (N-free) were tested. Treatment of the macrophages with PSU #1 had a negligible effect on phagocytosis whereas the N-free sample suppressed phagocytosis in a dose-related manner. The data show that alveolar macrophage Fc-receptor-mediated phagocytosis is affected by: carbon black and adsorbate identity and concentration, coverage of the carbon black with adsorbates, and the oxidizer used in the generation of particles emitted by a diesel engine. Images FIGURE 6. PMID:2401270

  12. Microwave assisted thermal treatment of defective coffee beans press cake for the production of adsorbents.

    PubMed

    Franca, Adriana S; Oliveira, Leandro S; Nunes, Anne A; Alves, Cibele C O

    2010-02-01

    Defective coffee press cake, a residue from coffee oil biodiesel production, was evaluated as an adsorbent for removal of basic dyes (methylene blue--MB) from aqueous solutions. The adsorbent was prepared by microwave treatment, providing a significant reduction in processing time coupled to an increase in adsorption capacity in comparison to conventional carbonization in a muffle furnace. Batch adsorption tests were performed at 25 degrees C and the effects of particle size, contact time, adsorbent dosage and initial solution pH were investigated. Adsorption kinetics was better described by a second-order model. The experimental adsorption equilibrium data were fitted to Langmuir, Freundlich and Tempkin adsorption models, with Langmuir providing the best fit. The results presented in this study show that microwave activation presents great potential as an alternative method in the production of adsorbents. PMID:19767204

  13. Adsorbent and adsorbent bed for materials capture and separation processes

    SciTech Connect

    Liu, Wei

    2011-01-25

    A method device and material for performing adsorption wherein a fluid mixture is passed through a channel in a structured adsorbent bed having a solid adsorbent comprised of adsorbent particles having a general diameter less than 100 um, loaded in a porous support matrix defining at least one straight flow channel. The adsorbent bed is configured to allow passage of a fluid through said channel and diffusion of a target material into said adsorbent under a pressure gradient driving force. The targeted molecular species in the fluid mixture diffuses across the porous support retaining layer, contacts the adsorbent, and adsorbs on the adsorbent, while the remaining species in the fluid mixture flows out of the channel.

  14. Poorly crystalline hydroxyapatite: A novel adsorbent for enhanced fulvic acid removal from aqueous solution

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Yang, Lei; Zhong, Wenhui; Cui, Jing; Wei, Zhenggui

    2015-03-01

    In this study, poorly crystalline hydroxyapatite (HAP) was developed as an efficient adsorbent for the removal of fulvic acid (FA) from aqueous solution. Surface functionality, crystallinity, and morphology of the synthetic adsorbent were studied by Fourier-transformation infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of various parameters such as crystallinity of adsorbent, contact time, adsorbent dosage, pH, initial adsorbate concentration, temperature, ionic strength and the presence of alkaline earth metal ions on FA adsorption were investigated. Results indicated that the nanosized HAP calcined at lower temperature was poorly crystalline (Xc = 0.23) and had better adsorption capacity for FA than those (Xc = 0.52, 0.86) calcined at higher temperature. FA removal was increased with increases of adsorbent dosage, temperature, ionic strength and the presence of alkali earth metal ions, but decreased as the pH increased. Kinetic studies showed that pseudo-second-order kinetic model better described the adsorption process. Equilibrium data were best described by Sips models, and the estimated maximum adsorption capacity of poorly crystalline HAP was 90.20 mg/g at 318 K, displaying higher efficiency for FA removal than previously reported adsorbents. FT-IR results revealed that FA adsorption over the adsorbent could be attributed to the surface complexation between the oxygen atom of functional groups of FA and calcium ions of HAP. Regeneration studies indicated that HAP could be recyclable for a long term. Findings of the present work highlight the potential for using poorly crystalline HAP nanoparticles as an effective and recyclable adsorbent for FA removal from aqueous solution.

  15. Adsorbent phosphates

    NASA Technical Reports Server (NTRS)

    Watanabe, S.

    1983-01-01

    An adsorbent which uses as its primary ingredient phosphoric acid salts of zirconium or titanium is presented. Production methods are discussed and several examples are detailed. Measurements of separating characteristics of some gases using the salts are given.

  16. Adsorption of dimethyl trisulfide from aqueous solution on a low-cost adsorbent: thermally activated pinecone

    NASA Astrophysics Data System (ADS)

    Shang, Jingge; He, Wei; Fan, Chengxin

    2015-01-01

    Thermally activated pinecone (TAP) was used for the adsorption of dimethyl trisulfide (DMTS) from aqueous solutions, which was proved to be the main odorous in algae-caused black bloom. The effects of adsorbent dosage, adsorbate concentration and contact time on DMTS biosorption were studied. The TAP produced at 600°C exhibited a relatively high surface area (519.69 m2/g) and excellent adsorption capacity. The results show that the adsorption of DMTS was initially fast and that the equilibrium time was 6 h. Higher initial DMTS concentrations led to lower removal percentages but higher adsorption capacity. The removal percentage of DMTS increased and the adsorption capacity of TAP decreased with an increase in adsorbent dosage. The adsorption process conforms well to a pseudo-second-order kinetics model. The adsorption of DMTS is more appropriately described by the Freundlich isotherm ( R 2 =0.996 1) than by the Langmuir isotherm ( R 2 =0.916 9). The results demonstrate that TAP could be an attractive low-cost adsorbent for removing DMTS from water.

  17. Natural Iraqi palygorskite clay as low cost adsorbent for the treatment of dye containing industrial wastewater.

    PubMed

    Nassir Taha, Dakhil; Sadi Samaka, Isra'a

    2012-01-01

    In this study, natural Iraqi low- cost locally available clay (palygorskite) was studied for its potential use as an adsorbent for removal Congo red from aqueous solutions. Batch type experiments were conducted to study the effect of contact time, initial pH of the dye solution, initial dye concentration, adsorbent dosage, and particle size of adsorbent on adsorption capacity of Congo red. The adsorption occurred very fast initially and attains equilibrium within 60 min. When the effect of pH of solution dye on the yield adsorption has been carried in a range of 2-10, the adsorption obtained was nearly the same with very slightly effect of pH and it was reported that above 49.07 mg/g of Cong red by palygorskite clay occurred in the pH range 2 to 10. It was observed that the removal of Congo red increase with increasing initial dye concentration and adsorbent dose, but, adsorption capacity decrease with increasing adsorbent dose. The adsorption capacity increase with decreasing particle size of adsorbent. The equilibrium adsorption data were interpreted using Langmuir and Freundlich isotherm models. The obtained results revealed that the equilibrium data closely followed both models, but the Langmuir isotherm fitted the data better. The maximum adsorption capacity was found to be 99 mg/g at ambient temperature. Results indicate that Iraqi palygorskite clay could be employed as a low cost alternative to commercial activated carbon in wastewater treatment for the removal of colour and dyes. PMID:23196874

  18. An efficient removal of methyl orange dye from aqueous solution by adsorption onto chitosan/MgO composite: A novel reusable adsorbent

    NASA Astrophysics Data System (ADS)

    Haldorai, Yuvaraj; Shim, Jae-Jin

    2014-02-01

    We report a novel multi-functional magnesium oxide (MgO) immobilized chitosan (CS) composite was prepared by chemical precipitation method. The CS-MgO composite was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy and zeta potential. The composite was applied as a novel adsorbent for removal of methyl orange model dye and the effect of adsorbent dosage, pH and contact time were studied. The adsorption kinetics followed a pseudo second order reaction. The adsorbent efficiency was unaltered even after five cycles of reuse. In addition, the composite exhibited a superior antibacterial efficacy of 93% within 24 h against Escherichia coli as measured by colony forming units. Based on the data of present investigation the composite being a biocompatible, eco-friendly and low-cost adsorbent with antibacterial activity could find potential applications in variety of fields and in particular environmental applications.

  19. Removal of lead and zinc ions from water by low cost adsorbents.

    PubMed

    Mishra, P C; Patel, R K

    2009-08-30

    In this study, activated carbon, kaolin, bentonite, blast furnace slag and fly ash were used as adsorbent with a particle size between 100 mesh and 200 mesh to remove the lead and zinc ions from water. The concentration of the solutions prepared was in the range of 50-100 mg/L for lead and zinc for single and binary systems which are diluted as required for batch experiments. The effect of contact time, pH and adsorbent dosage on removal of lead and zinc by adsorption was investigated. The equilibrium time was found to be 30 min for activated carbon and 3h for kaolin, bentonite, blast furnace slag and fly ash. The most effective pH value for lead and zinc removal was 6 for activated carbon. pH value did not effect lead and zinc removal significantly for other adsorbents. Adsorbent doses were varied from 5 g/L to 20 g/L for both lead and zinc solutions. An increase in adsorbent doses increases the percent removal of lead and zinc. A series of isotherm studies was undertaken and the data evaluated for compliance was found to match with the Langmuir and Freundlich isotherm models. To investigate the adsorption mechanism, the kinetic models were tested, and it follows second order kinetics. Kinetic studies reveals that blast furnace slag was not effective for lead and zinc removal. The bentonite and fly ash were effective for lead and zinc removal. PMID:19299083

  20. Experimental study of electric dipoles on an oxygen-adsorbed Si(100)-2 × 1 surface by non-contact scanning nonlinear dielectric microscopy

    SciTech Connect

    Suzuki, Masataka; Yamasue, Kohei Cho, Yasuo

    2015-07-20

    Oxygen-adsorption on a Si(100)-2 × 1 surface is investigated by using non-contact scanning nonlinear dielectric microscopy (NC-SNDM). On the Si(100)-2 × 1 surface exposed to oxygen (O{sub 2}) gas at room temperature, several variations in atomic configuration and electric dipole moment of dimers are observed. Models are proposed for oxygen adsorption which are consistent with the topographies and electric dipole moment distributions obtained by NC-SNDM.

  1. Chitosan/Graphene Oxide Composite as an Effective Adsorbent for Reactive Red Dye Removal.

    PubMed

    Guo, Xiaoqing; Qu, Lijun; Tian, Mingwei; Zhu, Shifeng; Zhang, Xiansheng; Tang, Xiaoning; Sun, Kaikai

    2016-07-01

    Chitosan, modified with different dosages of graphene oxide (GO) and reduced graphene oxide (rGO), was first prepared, and its adsorption capacity for reactive red (RR) dye in aqueous solutions was investigated, in this paper. The structure and morphology of the adsorbents were characterized by FT-IR, XRD, SEM, EDX, BET, and TGA. The effect of varying parameters (pH, temperature, adsorbent loading, and contact time) was also investigated. The maximum adsorption capacity based on the Langmuir model was found to be 32.16 mg/g. In addition, experimental kinetic data were analyzed by the psuedo-first order and psuedo-second order equation models. The psuedo-second order model proved to be the best model for the adsorption system, which suggested that adsorption might be controlled by the chemical rate-limiting step through sharing of electrons or by covalent forces. PMID:27329054

  2. Examining Adsorbed Polymer Conformations with Fluorescence Imaging

    NASA Astrophysics Data System (ADS)

    Parkes, Maria; Chennaoui, Mourad; Wong, Janet; Tribology Group, Dept. of Mechanical Engineering Team

    2011-03-01

    The conformation of adsorbed polymers can have significant impact on their properties such as dynamics and elasticity as well as their ability to take part in reactions with other molecules. Experimental research to determine adsorbed polymer conformation has relied mainly on atomic force microscopy (AFM) studies. During an AFM scan, the contact between the scanning probe and the polymer could affect the polymer conformation, particularly where parts of the polymer might have formed projected loops and tails. In this work, conformations of model polymers are examined with total internal reflection fluorescence microscopy (TIRFM). The advantage of TIRFM over AFM is that TIRFM is a non contact technique. Lambda DNA labelled along its length with fluorescent probes was adsorbed in a projected 2D -- 3D state. With TIRFM, the relationship between intensity and depth was used as a basis to determine how the conformation of the adsorbed polymers evolved with time using our custom algorithm.

  3. Controlled release liquid dosage formulation

    DOEpatents

    Benton, Ben F.; Gardner, David L.

    1989-01-01

    A liquid dual coated dosage formulation sustained release pharmaceutic having substantial shelf life prior to ingestion is disclosed. A dual coating is applied over controlled release cores to form dosage forms and the coatings comprise fats melting at less than approximately 101.degree. F. overcoated with cellulose acetate phthalate or zein. The dual coated dosage forms are dispersed in a sugar based acidic liquid carrier such as high fructose corn syrup and display a shelf life of up to approximately at least 45 days while still retaining their release profiles following ingestion. Cellulose acetate phthalate coated dosage form cores can in addition be dispersed in aqueous liquids of pH <5.

  4. Synthesis of nickel sulfide nanoparticles loaded on activated carbon as a novel adsorbent for the competitive removal of Methylene blue and Safranin-O.

    PubMed

    Ghaedi, M; Pakniat, M; Mahmoudi, Z; Hajati, S; Sahraei, R; Daneshfar, A

    2014-04-01

    Nickel sulfide nanoparticle-loaded activated carbon (NiS-NP-AC) were synthesized as a novel adsorbent for simultaneous and rapid adsorption of Methylene blue (MB) and Safranin-O (SO), as most together compounds in wastewater. NiS-NP-AC was characterized using different techniques such as UV-visible, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Brunauer-Emmett-Teller (BET). The surface area of the adsorbent was found to be very high (1018m(2)/g according BET). By using central composite design (CCD), the effects of variables such as pH, adsorbent dosage, MB concentration, SO concentration and contact time on binary dyes removal were examined and optimized values were found to be 8.1, 0.022g, 17.8mg/L, and 5mg/L and 5.46min, respectively. The very short time required for the dyes removal makes this novel adsorbent as a promising tool for wastewater treatment applications. Different models were applied to analyze experimental isotherm data. Modified-extended Langmuir model showed good fit to equilibrium data with maximum adsorption capacity at 0.022g of adsorbent. An empirical extension of competitive modified-extended Langmuir model was proposed to predict the simultaneous adsorption behavior of MB and SO. Kinetic models were applied to fit the experimental data at various adsorbent dosages and initial dyes concentrations. It was seen that pseudo-second-order equation is suitable to fit the experimental data. Individual removalof each dye was also studied. PMID:24412794

  5. Carbonaceous adsorbent regeneration and halocarbon displacement by hydrocarbon gases

    DOEpatents

    Senum, G.I.; Dietz, R.N.

    1994-04-05

    This invention describes a process for regeneration of halocarbon bearing carbonaceous adsorbents through which a carbonaceous adsorbent is contacted with hydrocarbon gases, preferably propane, butane and pentane at near room temperatures and at atmospheric pressure. As the hydrocarbon gases come in contact with the adsorbent, the hydrocarbons displace the halocarbons by physical adsorption. As a result of using this process, the halocarbon concentration and the hydrocarbon eluant is increased thereby allowing for an easier recovery of pure halocarbons. By using the process of this invention, carbonaceous adsorbents can be regenerated by an inexpensive process which also allows for subsequent re-use of the recovered halocarbons. 8 figures.

  6. Carbonaceous adsorbent regeneration and halocarbon displacement by hydrocarbon gases

    DOEpatents

    Senum, Gunnar I.; Dietz, Russell N.

    1994-01-01

    This invention describes a process for regeneration of halocarbon bearing carbonaceous adsorbents through which a carbonaceous adsorbent is contacted with hydrocarbon gases, preferably propane, butane and pentane at near room temperatures and at atmospheric pressure. As the hydrocarbon gases come in contact with the adsorbent, the hydrocarbons displace the halocarbons by physical adsorption. As a result of using this process, the halocarbon concentration and the hydrocarbon eluant is increased thereby allowing for an easier recovery of pure halocarbons. By using the process of this invention, carbonaceous adsorbents can be regenerated by an inexpensive process which also allows for subsequent re-use of the recovered halocarbons.

  7. A novel agricultural waste adsorbent for the removal of lead (II) ions from aqueous solutions.

    PubMed

    Ibrahim, M N Mohamad; Ngah, W S Wan; Norliyana, M S; Daud, W R Wan; Rafatullah, M; Sulaiman, O; Hashim, R

    2010-10-15

    The present study explores the ability of modified soda lignin (MSL) extracted from oil palm empty fruit bunches (EFB) in removing lead (II) ions from aqueous solutions. The effect of contact time, point zero charge (pH(pzc)) and pH of the solution, initial metal ion concentration and adsorbent dosage on the removal process were investigated. Furthermore, the MSL is characterized by SEM, XRF, FT-IR and surface area analysis. Equilibrium adsorption isotherms and kinetics were investigated. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of adsorption. The kinetic data obtained at different initial concentrations were analyzed using pseudo-first-order and pseudo-second-order models. The results provide strong evidence to support the hypothesis of adsorption mechanism. PMID:20619537

  8. Volumetric Interpretation of Protein Adsorption: Capacity Scaling with Adsorbate Molecular Weight and Adsorbent Surface Energy

    PubMed Central

    Parhi, Purnendu; Golas, Avantika; Barnthip, Naris; Noh, Hyeran; Vogler, Erwin A.

    2009-01-01

    Silanized-glass-particle adsorbent capacities are extracted from adsorption isotherms of human serum albumin (HSA, 66 kDa), immunoglobulin G (IgG, 160 kDa), fibrinogen (Fib, 341 kDa), and immunoglobulin M (IgM, 1000 kDa) for adsorbent surface energies sampling the observable range of water wettability. Adsorbent capacity expressed as either mass-or-moles per-unit-adsorbent-area increases with protein molecular weight (MW) in a manner that is quantitatively inconsistent with the idea that proteins adsorb as a monolayer at the solution-material interface in any physically-realizable configuration or state of denaturation. Capacity decreases monotonically with increasing adsorbent hydrophilicity to the limit-of-detection (LOD) near τo = 30 dyne/cm (θ~65o) for all protein/surface combinations studied (where τo≡γlvocosθ is the water adhesion tension, γlvo is the interfacial tension of pure-buffer solution, and θ is the buffer advancing contact angle). Experimental evidence thus shows that adsorbent capacity depends on both adsorbent surface energy and adsorbate size. Comparison of theory to experiment implies that proteins do not adsorb onto a two-dimensional (2D) interfacial plane as frequently depicted in the literature but rather partition from solution into a three-dimensional (3D) interphase region that separates the physical surface from bulk solution. This interphase has a finite volume related to the dimensions of hydrated protein in the adsorbed state (defining “layer” thickness). The interphase can be comprised of a number of adsorbed-protein layers depending on the solution concentration in which adsorbent is immersed, molecular volume of the adsorbing protein (proportional to MW), and adsorbent hydrophilicity. Multilayer adsorption accounts for adsorbent capacity over-and-above monolayer and is inconsistent with the idea that protein adsorbs to surfaces primarily through protein/surface interactions because proteins within second (or higher

  9. Hysteresis during contact angles measurement.

    PubMed

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

    2010-03-15

    A theory, based on the presence of an adsorbed film in the vicinity of the triple contact line, provides a molecular interpretation of intrinsic hysteresis during the measurement of static contact angles. Static contact angles are measured by placing a sessile drop on top of a flat solid surface. If the solid surface has not been previously in contact with a vapor phase saturated with the molecules of the liquid phase, the solid surface is free of adsorbed liquid molecules. In the absence of an adsorbed film, molecular forces configure an advancing contact angle larger than the static contact angle. After some time, due to an evaporation/adsorption process, the interface of the drop coexists with an adsorbed film of liquid molecules as part of the equilibrium configuration, denoted as the static contact angle. This equilibrium configuration is metastable because the droplet has a larger vapor pressure than the surrounding flat film. As the drop evaporates, the vapor/liquid interface contracts and the apparent contact line moves towards the center of the drop. During this process, the film left behind is thicker than the adsorbed film and molecular attraction results in a receding contact angle, smaller than the equilibrium contact angle. PMID:20060981

  10. Lead removal with adsorbing colloid flotation

    SciTech Connect

    Thackston, E.L.; Wilson, D.J.; Hanson, J.S.; Miller, D.L. Jr.

    1980-02-01

    A process that removes lead from industrial waste by adsorbing colloid foam flotation has been designed and demonstrated. A system of ferric chloride and sodium lauryl sulfate, both relatively inexpensive chemicals, gave good performance with optimum dosages of sodium lauryl sulfate at 40 mg/l and trivalent iron at 150 mg/l. With optimum chemical and hydraulic conditions, the pilot plant was able to produce effluents with lead concentrations of less than 0.5 mg/l. The process may be especially attractive where space for heavy metals removal equipment is extremely limited.

  11. X-Chromosome dosage compensation.

    PubMed

    Meyer, Barbara J

    2005-01-01

    In mammals, flies, and worms, sex is determined by distinctive regulatory mechanisms that cause males (XO or XY) and females (XX) to differ in their dose of X chromosomes. In each species, an essential X chromosome-wide process called dosage compensation ensures that somatic cells of either sex express equal levels of X-linked gene products. The strategies used to achieve dosage compensation are diverse, but in all cases, specialized complexes are targeted specifically to the X chromosome(s) of only one sex to regulate transcript levels. In C. elegans, this sex-specific targeting of the dosage compensation complex (DCC) is controlled by the same developmental signal that establishes sex, the ratio of X chromosomes to sets of autosomes (X:A signal). Molecular components of this chromosome counting process have been defined. Following a common step of regulation, sex determination and dosage compensation are controlled by distinct genetic pathways. C. elegans dosage compensation is implemented by a protein complex that binds both X chromosomes of hermaphrodites to reduce transcript levels by one-half. The dosage compensation complex resembles the conserved 13S condensin complex required for both mitotic and meiotic chromosome resolution and condensation, implying the recruitment of ancient proteins to the new task of regulating gene expression. Within each C. elegans somatic cell, one of the DCC components also participates in the separate mitotic/meiotic condensin complex. Other DCC components play pivotal roles in regulating the number and distribution of crossovers during meiosis. The strategy by which C. elegans X chromosomes attract the condensin-like DCC is known. Small, well-dispersed X-recognition elements act as entry sites to recruit the dosage compensation complex and to nucleate spreading of the complex to X regions that lack recruitment sites. In this manner, a repressed chromatin state is spread in cis over short or long distances, thus establishing the

  12. User-oriented batch reactor solutions to the homogeneous surface diffusion model for different activated carbon dosages.

    PubMed

    Zhang, Qiong; Crittenden, John; Hristovski, Kiril; Hand, David; Westerhoff, Paul

    2009-04-01

    This paper presents a simplified approach and user-oriented solutions to the homogeneous surface diffusion model (HSDM) equations for determining the surface diffusivity using a batch reactor system. Once the surface diffusivity is known, this model could also be used to estimate the performance of activated carbon (AC) applications as a function of contact time. In addition, fixed-bed performance can be predicted using the user-oriented solutions to the HSDM for fixed beds. The step-by-step procedure for determining surface diffusion coefficients of an activated carbon adsorber, which was initially developed by Hand, Crittenden and Thacker in 1983 for a carbon dose where C(equilibrium)/C(0)=0.5, is modified to allow calculations for different carbon dosages. This modification provides solutions to the HSDM equations for different activated carbon dosages. The solutions to the HSDM framework are provided as simplified algebraic equations suitable for quick and easy estimations of D(S). The excel spread sheet is provided in the supplemental information and a detailed example is discussed. PMID:19249812

  13. Use of sepiolite as an adsorbent for the removal of copper (II) from industrial waste leachate

    NASA Astrophysics Data System (ADS)

    Gamze Turan, N.; Ardali, Yüksel

    2013-04-01

    as talc, but it has discontinuities and inversion of the silica sheets, which give rise to structural tunnels and blocks. In the inner blocks, all corners of the silica tetrahedral are connected to adjacent blocks, but in the outer blocks, some of the corners are Si atoms bound to hydroxyls (Si-OH). This unique structure allows the penetration of organic and inorganic species into the structure and assigns sepiolite an industrial importance in adsorption. The objective of the present study is to investigate the feasibility of using sepiolite for the adsorptive removal of Cu (II) from the industrial waste leachate. The adsorption capacities and sorption efficiencies are determined. The pseudo first order, the pseudo-second order, Elovich and the intra particle diffusion kinetic models are used to describe the kinetic data to estimate the rate constants. The adsorption of Cu (II) from the aqueous leachate of industrial wastes onto sepiolite was performed using a batch equilibrium technique. At first stage, one-factor-at-a-time experiments were performed to see the individual effects of initial pH, adsorbent dosage and contact time. The adsorption of Cu (II) was favorably influenced by an increase in the adsorbent dosage. The maximum percent removal of Cu (II) were observed at pH>6, and significantly decreased at lower pH value. The optimum contact time is found as 10 min. for the removal of Cu (II). The increment in contact time from 10 min. to 120 min. did not show a significant effect on efficiency. The maximum Cu (II) adsorption efficiencies were obtained at 94.45%. The pseudo second order kinetic model agrees very well with the dynamical behavior for the adsorption of Cu (II) from aqueous leachate of industrial waste onto sepiolite. The results indicate that the use of sepiolite that is locally available and almost free of cost as an adsorbent could be a viable alternative to activated carbon for the removal of Cu (II) ions from aqueous solutions.

  14. Molecular Adsorber Coating

    NASA Technical Reports Server (NTRS)

    Straka, Sharon; Peters, Wanda; Hasegawa, Mark; Hedgeland, Randy; Petro, John; Novo-Gradac, Kevin; Wong, Alfred; Triolo, Jack; Miller, Cory

    2011-01-01

    A document discusses a zeolite-based sprayable molecular adsorber coating that has been developed to alleviate the size and weight issues of current ceramic puck-based technology, while providing a configuration that more projects can use to protect against degradation from outgassed materials within a spacecraft, particularly contamination-sensitive instruments. This coating system demonstrates five times the adsorption capacity of previously developed adsorber coating slurries. The molecular adsorber formulation was developed and refined, and a procedure for spray application was developed. Samples were spray-coated and tested for capacity, thermal optical/radiative properties, coating adhesion, and thermal cycling. Work performed during this study indicates that the molecular adsorber formulation can be applied to aluminum, stainless steel, or other metal substrates that can accept silicate-based coatings. The coating can also function as a thermal- control coating. This adsorber will dramatically reduce the mass and volume restrictions, and is less expensive than the currently used molecular adsorber puck design.

  15. Size selective hydrophobic adsorbent for organic molecules

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K. (Inventor); Hickey, Gregory S. (Inventor)

    1997-01-01

    The present invention relates to an adsorbent formed by the pyrolysis of a hydrophobic silica with a pore size greater than 5 .ANG., such as SILICALITE.TM., with a molecular sieving polymer precursor such as polyfurfuryl alcohol, polyacrylonitrile, polyvinylidene chloride, phenol-formaldehyde resin, polyvinylidene difluoride and mixtures thereof. Polyfurfuryl alcohol is the most preferred. The adsorbent produced by the pyrolysis has a silicon to carbon mole ratio of between about 10:1 and 1:3, and preferably about 2:1 to 1:2, most preferably 1:1. The pyrolysis is performed as a ramped temperature program between about 100.degree. and 800.degree. C., and preferably between about 100.degree. and 600.degree. C. The present invention also relates to a method for selectively adsorbing organic molecules having a molecular size (mean molecular diameter) of between about 3 and 6 .ANG. comprising contacting a vapor containing the small organic molecules to be adsorbed with the adsorbent composition of the present invention.

  16. Complementary Barrier Infrared Detector (CBIRD) Contact Methods

    NASA Technical Reports Server (NTRS)

    Ting, David Z.; Hill, Cory J.; Gunapala, Sarath D.

    2013-01-01

    The performance of the CBIRD detector is enhanced by using new device contacting methods that have been developed. The detector structure features a narrow gap adsorber sandwiched between a pair of complementary, unipolar barriers that are, in turn, surrounded by contact layers. In this innovation, the contact adjacent to the hole barrier is doped n-type, while the contact adjacent to the electron barrier is doped p-type. The contact layers can have wider bandgaps than the adsorber layer, so long as good electrical contacts are made to them. If good electrical contacts are made to either (or both) of the barriers, then one could contact the barrier(s) directly, obviating the need for additional contact layers. Both the left and right contacts can be doped either n-type or ptype. Having an n-type contact layer next to the electron barrier creates a second p-n junction (the first being the one between the hole barrier and the adsorber) over which applied bias could drop. This reduces the voltage drop over the adsorber, thereby reducing dark current generation in the adsorber region.

  17. Regenerative adsorbent heat pump

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1991-01-01

    A regenerative adsorbent heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system and at least a portion of the heat of adsorption. A series of at least four compressors containing an adsorbent is provided. A large amount of heat is transferred from compressor to compressor so that heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

  18. Removal effects and mechanisms of Microcystic aeruginosa by Chitosan-modified Adsorbent

    NASA Astrophysics Data System (ADS)

    Yang, Xi; Wu, Cuirong; He, Yan; Zhang, Bingru; Li, Fengting

    2010-11-01

    The health of humans and other organisms is threatened by increasingly serious water contamination by algae in all the country's major lakes such as Taihu Lake. This experiment was conducted to investigate the removal effects and mechanism of Microcystic aeruginosa by Chitosan-modified adsorbent, with comparison of polyaluminium chloride (PAC) and poly ferric sulfate (PFS). Microcystic aeruginosa grown in the laboratory was used for this experiment. The results showed that the algae-removal efficiency of Chitosan-modified adsorbent presents a good performance. When the dosage of the adsorbent reached 20 ppm, the turbidity and the chlorophyll a of treated water dropped by 90% and 86%, respectively. Compared to conventional coagulation, the dosage was reduced. The adhesive bridge effect of Chitosan and adsorption of modified adsorbent provided an important complement to subsequent dehydrating treatment for algae.

  19. Radiopharmaceutical dosage selection for pediatric nuclear medicine

    SciTech Connect

    Shore, R.M.; Hendee, W.R.

    1986-02-01

    To identify the most rational method for adjusting adult radiopharmaceutical dosages for children, four methods of dosage computation were examined from the perspectives of diagnostic adequacy and radiation absorbed dose. For static imaging, information density is the most important factor in study quality, and adjustment of dosage by body weight (Wt) for thick organs, and body surface area (BSA) for thin organs is recommended. Compared with adults, small children receive less radiation exposure if radiopharmaceutical dosages are adjusted by Wt, and slightly greater exposure if dosages are adjusted by BSA. For dynamic imaging studies, dosage requirements are governed by the spatial resolution needed for region of interest assignment, and the statistical reliability of the time-activity data. For dynamic renal imaging, renograms of similar quality are obtained if dosages are adjusted by height (Ht). Dynamic cardiac studies might appear to require dosages even larger than those adjusted by Ht which would result in higher radiation absorbed doses to pediatric patients. However, smaller dosages can be used in children by prolonging the imaging time and accepting lower temporal resolution. Dosage requirements for dynamic studies depend on which physiologic characteristics are measured from the time-activity data. Since the measurements of some characteristics demand higher count rates than others, dosage requirements ultimately depend on which measurements are clinically necessary. Close attention to the factors that determine these requirements may yield significant reduction in dosages, and thus in radiation exposure, for patients of all ages.

  20. Contact dermatitis

    MedlinePlus

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

  1. Novel adhesive properties of poly(ethylene-oxide) adsorbed nanolayers

    NASA Astrophysics Data System (ADS)

    Zeng, Wenduo

    Solid-polymer interfaces play crucial roles in the multidisciplinary field of nanotechnology and are the confluence of physics, chemistry, biology, and engineering. There is now growing evidence that polymer chains irreversibly adsorb even onto weakly attractive solid surfaces, forming a nanometer-thick adsorbed polymer layer ("adsorbed polymer nanolayers"). It has also been reported that the adsorbed layers greatly impact on local structures and properties of supported polymer thin films. In this thesis, I aim to clarify adhesive and tribological properties of adsorbed poly(ethylene-oxide) (PEO) nanolayers onto silicon (Si) substrates, which remain unsolved so far. The adsorbed nanolayers were prepared by the established protocol: one has to equilibrate the melt or dense solution against a solid surface; the unadsorbed chains can be then removed by a good solvent, while the adsorbed chains are assumed to maintain the same conformation due to the irreversible freezing through many physical solid-segment contacts. I firstly characterized the formation process and the surface/film structures of the adsorbed nanolayers by using X-ray reflectivity, grazing incidence X-ray diffraction, and atomic force microscopy. Secondly, to compare the surface energy of the adsorbed layers with the bulk, static contact angle measurements with two liquids (water and glycerol) were carried out using a optical contact angle meter equipped with a video camera. Thirdly, I designed and constructed a custom-built adhesion-testing device to quantify the adhesive property. The experimental results provide new insight into the microscopic structure - macroscopic property relationship at the solid-polymer interface.

  2. The Enigma of Rapamycin Dosage.

    PubMed

    Mukhopadhyay, Suman; Frias, Maria A; Chatterjee, Amrita; Yellen, Paige; Foster, David A

    2016-03-01

    The mTOR pathway is a critical regulator of cell growth, proliferation, metabolism, and survival. Dysregulation of mTOR signaling has been observed in most cancers and, thus, the mTOR pathway has been extensively studied for therapeutic intervention. Rapamycin is a natural product that inhibits mTOR with high specificity. However, its efficacy varies by dose in several contexts. First, different doses of rapamycin are needed to suppress mTOR in different cell lines; second, different doses of rapamycin are needed to suppress the phosphorylation of different mTOR substrates; and third, there is a differential sensitivity of the two mTOR complexes mTORC1 and mTORC2 to rapamycin. Intriguingly, the enigmatic properties of rapamycin dosage can be explained in large part by the competition between rapamycin and phosphatidic acid (PA) for mTOR. Rapamycin and PA have opposite effects on mTOR whereby rapamycin destabilizes and PA stabilizes both mTOR complexes. In this review, we discuss the properties of rapamycin dosage in the context of anticancer therapeutics. Mol Cancer Ther; 15(3); 347-53. ©2016 AACR. PMID:26916116

  3. Kinetics and isotherm analysis of Tropaeoline 000 adsorption onto unsaturated polyester resin (UPR): a non-carbon adsorbent.

    PubMed

    Jain, Rajeev; Sharma, Pooja; Sikarwar, Shalini

    2013-03-01

    The presence of dyes in water is undesirable due to the toxicological impact of their entrance into the food chain. Owing to the recalcitrant nature of dyes to biological oxidation, a tertiary treatment like adsorption is required. In the present study, unsaturated polyester resin (UPR) has been used as a sorbent in the treatment of dye-contaminated water. Different concentrations of Tropaeoline 000 containing water were treated with UPR. The preliminary investigations were carried out by batch adsorption to examine the effects of pH, adsorbate concentration, adsorbent dosage, contact time, and temperature. A plausible mechanism for the ongoing adsorption process and thermodynamic parameters have also been obtained from Langmuir and Freundlich adsorption isotherm models. Thermodynamic parameter showed that the sorption process of Tropaeoline 000 onto activated carbon (AC) and UPR were feasible, spontaneous, and endothermic under studied conditions. The estimated values for (ΔG) are -10.48 × 10(3) and -6.098 × 10(3) kJ mol(-1) over AC and UPR at 303 K (30 °C), indicating towards a spontaneous process. The adsorption process followed pseudo-first-order model. The mass transfer property of the sorption process was studied using Lagergren pseudo-first-order kinetic models. The values of % removal and k (ad) for dye systems were calculated at different temperatures (303-323 K). The mechanism of the adsorption process was determined from the intraparticle diffusion model. PMID:22689095

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

    DOEpatents

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

    1999-01-01

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

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

    DOEpatents

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

    1999-06-29

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

  6. Contact Dermatitis

    MedlinePlus

    ... care Kids’ zone Video library Find a dermatologist Contact dermatitis Overview Contact dermatitis: Many health care workers ... to touching her face while wearing latex gloves. Contact dermatitis: Overview Almost everyone gets this type of ...

  7. Estimated Radiation Dosage on Mars

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This global map of Mars shows the estimated radiation dosages from cosmic rays reaching the surface, a serious health concern for any future human exploration of the planet.

    The estimates are based on cosmic-radiation measurements by the Mars radiation environment experiment, an instrument on NASA's Mars 2000 Odyssey spacecraft, plus information about Mars' surface elevations from the laser altimeter instrument on NASA's Mars Global Surveyor. The areas of Mars expected to have the lowest levels of cosmic radiation are where the elevation is lowest, because those areas have more atmosphere above them to block out some of the radiation. Earth's thick atmosphere shields us from most cosmic radiation, but Mars has a much thinner atmosphere than we have on Earth.

    The colors in the map refer to the estimated annual dose equivalent in rems, a unit of radiation dose. The range is generally from 10 rems(color-coded dark blue) to 20 rems (color coded dark red). Radiation exposure for astronauts on the International Space Station in Earth orbit is typically equivalent to an annualized rate of 20 to 40 rems.

    NASA's Jet Propulsion Laboratory, Pasadena, Calif. manages the 2001 Mars Odyssey and Mars Global Surveyor missions for NASA's Office of Space Science, Washington D.C. The Mars radiation environment experiment was developed by NASA's Johnson Space Center, Houston. Lockheed Martin Astronautics, Denver, is the prime contractor for Odyssey, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  8. Adsorbed Water Illustration

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Thermal and Electrical Conductivity Probe on NASA's Phoenix Mars Lander detected small and variable amounts of water in the Martian soil.

    In this schematic illustration, water molecules are represented in red and white; soil minerals are represented in green and blue. The water, neither liquid, vapor, nor solid, adheres in very thin films of molecules to the surfaces of soil minerals. The left half illustrates an interpretation of less water being adsorbed onto the soil-particle surface during a period when the tilt, or obliquity, of Mars' rotation axis is small, as it is in the present. The right half illustrates a thicker film of water during a time when the obliquity is greater, as it is during cycles on time scales of hundreds of thousands of years. As the humidity of the atmosphere increases, more water accumulates on mineral surfaces. Thicker films behave increasingly like liquid water.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  9. Advances in solid dosage form manufacturing technology.

    PubMed

    Andrews, Gavin P

    2007-12-15

    Currently, the pharmaceutical and healthcare industries are moving through a period of unparalleled change. Major multinational pharmaceutical companies are restructuring, consolidating, merging and more importantly critically assessing their competitiveness to ensure constant growth in an ever-more demanding market where the cost of developing novel products is continuously increasing. The pharmaceutical manufacturing processes currently in existence for the production of solid oral dosage forms are associated with significant disadvantages and in many instances provide many processing problems. Therefore, it is well accepted that there is an increasing need for alternative processes to dramatically improve powder processing, and more importantly to ensure that acceptable, reproducible solid dosage forms can be manufactured. Consequently, pharmaceutical companies are beginning to invest in innovative processes capable of producing solid dosage forms that better meet the needs of the patient while providing efficient manufacturing operations. This article discusses two emerging solid dosage form manufacturing technologies, namely hot-melt extrusion and fluidized hot-melt granulation. PMID:17855217

  10. Control of acid gases using a fluidized bed adsorber.

    PubMed

    Chiang, Bo-Chin; Wey, Ming-Yen; Yeh, Chia-Lin

    2003-08-01

    During incineration, secondary pollutants such as acid gases, organic compounds, heavy metals and particulates are generated. Among these pollutants, the acid gases, including sulfur oxides (SO(x)) and hydrogen chloride (HCl), can cause corrosion of the incinerator piping and can generate acid rain after being emitted to the atmosphere. To address this problem, the present study used a novel combination of air pollution control devices (APCDs), composed of a fluidized bed adsorber integrated with a fabric filter. The major objective of the work is to demonstrate the performance of a fluidized bed adsorber for removal of acid gases from flue gas of an incinerator. The adsorbents added in the fluidized bed adsorber were mainly granular activated carbon (AC; with or without chemical treatment) and with calcium oxide used as an additive. The advantages of a fluidized bed reactor for high mass transfer and high gas-solid contact can enhance the removal of acid gases when using a dry method. On the other hand, because the fluidized bed can filter particles, fine particles prior to and after passing through the fluidized bed adsorber were investigated. The competing adsorption on activated carbon between different characteristics of pollutants was also given preliminary discussion. The results indicate that the removal efficiencies of the investigated acid gases, SO(2) and HCl, are higher than 94 and 87%, respectively. Thus, a fluidized bed adsorber integrated with a fabric filter has the potential to replace conventional APCDs, even when there are other pollutants at the same time. PMID:12935758

  11. Photopatch test reactivity: effect of photoallergen concentration and UVA dosaging.

    PubMed

    Hasan, T; Jansen, C T

    1996-06-01

    We have studied the influence of variations in allergen concentration and UVA dosaging on the results of photopatch testing with the Scandinavian standard photopatch series in 29 patients with photocontact and/or contact allergy to 1 or several of the allergens in that series. Photocontact test reactions were more sensitive to allergen dilution than plain contact test reactions. Even dilution from the standard 5% to 2.5% significantly reduced para-aminobenzoic acid photocontact test reactions. Reducing the UVA dose from the standard 5 J/cm2 to 2.5 or 1 J/cm2 in 2 out of 5 cases turned a significant (++) reaction into a doubtful one (+). Increasing the standard UVA dose of 5 J/ cm2 to 20-40 J/cm2 turned a single + photocontact reaction to trichlorcarbanilide and a single 1 + plain contact reaction to chlorhexidine into ++ reactions. In the majority of cases, however, neither photocontact nor plain contact test reactions were augemented by UVA doses up to 80 J/cm2. We conclude that a UVA dose of 5 J/cm2 is sufficient for eliciting photocontact allergic test reactions, and that a reduction of either the UVA dose level or the standard allergen concentrations of the Scandinavian photopatch test guidelines may cause loss of significant photocontact test reactions in a proportion of the cases. PMID:8879921

  12. CNS myelination and PLP gene dosage.

    PubMed

    Woodward, K; Malcolm, S

    2001-08-01

    The phenomenon of gene dosage effects demonstrates that the mechanisms of some genetic diseases are best recognised at the genomic level. Classical gene mutation screening approaches utilising PCR are unsuccessful in unravelling the basis of disease because the gene sequence is unaltered and only the copy number is different. Techniques for detecting DNA dosage are required. Examples of haploinsufficiency and gene deletions are well documented, but increased gene dosage is also an important genetic mechanism in disorders involving myelin proteins in the central (CNS) and peripheral nervous system (PNS). Here we review the dosage effects and mutations of the proteolipid protein (PLP) gene that causes Pelizaeus-Merzbacher disease (PMD) and spastic paraplegia Type 2 (SPG2) disorders of CNS myelination. Similarities are drawn with the peripheral neuropathies Charcot-Marie-Tooth disease Type 1 (CMT1A) and hereditary neuropathy with liability to pressure palsies (HNPP) that are also caused by dosage effects and mutations in a single myelin protein gene (peripheral myelin protein 22, PMP-22). We compare the different mutational mechanisms in man and analogous mouse models that suggest a function for PLP beyond its structural role in myelin. We focus on the increased dosage of the PLP gene that is the major cause of PMD and results from a submicroscopic duplication of Xq22. Other clinical phenotypes may arise from gene dosage imbalance with the potential effect of submicroscopic duplications and deletions of the genome being underestimated. Genome sequencing may identify intrinsic structural properties of the DNA with greater susceptibility to these rearrangements and thereby reflect structural changes in the genome. PMID:11535114

  13. Investigation on removal of malachite green using EM based compost as adsorbent.

    PubMed

    Bhagavathi Pushpa, T; Vijayaraghavan, J; Sardhar Basha, S J; Sekaran, V; Vijayaraghavan, K; Jegan, J

    2015-08-01

    The discarded materials from different sources can be utilized as effective materials in wastewater remediation. This proposed study was aimed mainly to investigate the possibility of Effective Microorganisms based compost (EMKC), which is derived from the kitchen solid waste, as a non-conventional low cost adsorbent for the removal of malachite green from aqueous solution. Batch experiments were carried out to evaluate the optimum operating parameters like pH (2-9), initial dye concentration (50-1000mg/L), adsorbent particle size (0.6-2.36mm) and adsorbent dosage (2-12g/L). EMKC recorded maximum uptake of 136.6mg/g of MG at pH 8, initial dye concentration 1000mg/L, adsorbent particle size 1.18mm and adsorbent dosage 4g/L. Two and three parameter adsorption models were employed to describe experimental biosorption isotherm data. The results revealed that the Sips model resulted in better fit than other models. The pseudo-first and -second order models were applied to describe kinetic data, of which the pseudo-second order described experimental data better with high correlation coefficient. This investigation suggested that EMKC could be an effective and low cost material for the removal of malachite green dye from aqueous solution. PMID:25938698

  14. [Preparation and investigation of gemfibrozil + dimethyl-beta-cyclodextrin products and solid dosage forms].

    PubMed

    Hassan, Bin Hassan; Aigner, Zoltán; Kása, Péter; Hódi, Klára; Eros, István

    2005-01-01

    Gemfibrozil is a lipid-regulating active substance. Dimethyl-beta-cyclodextrin products were prepared from this sparingly soluble pharmacon by means of methods such as physical mixing, kneading, spray drying and ultrasonication. Solid dosage forms (hydroxypropylmethyl cellulose /HPMC/ capsules and tablets) were prepared from the selected products on the basis of their dissolution profile and the in vitro membrane diffusion results. This publication details the results of electronmicroscopic morphological studies, particle size analysis and wetting contact angle determinations, and also the preparation and examination of the resulting solid dosage forms. PMID:16318236

  15. Telocyte's contacts.

    PubMed

    Faussone-Pellegrini, Maria-Simonetta; Gherghiceanu, Mihaela

    2016-07-01

    Telocytes (TC) are an interstitial cell type located in the connective tissue of many organs of humans and laboratory mammals. By means of homocellular contacts, TC build a scaffold whose meshes integrity and continuity are guaranteed by those contacts having a mechanical function; those contacts acting as sites of intercellular communication allow exchanging information and spreading signals. Heterocellular contacts between TC and a great variety of cell types give origin to mixed networks. TC, by means of all these types of contacts, their interaction with the extracellular matrix and their vicinity to nerve endings, are part of an integrated system playing tissue/organ-specific roles. PMID:26826524

  16. Nitric oxide releasing material adsorbs more fibrinogen.

    PubMed

    Lantvit, Sarah M; Barrett, Brittany J; Reynolds, Melissa M

    2013-11-01

    One mechanism of the failure of blood-contacting devices is clotting. Nitric oxide (NO) releasing materials are seen as a viable solution to the mediation of surface clotting by preventing platelet activation; however, NO's involvement in preventing clot formation extends beyond controlling platelet function. In this study, we evaluate NO's effect on factor XII (fibrinogen) adsorption and activation, which causes the initiation of the intrinsic arm of the coagulation cascade. This is done by utilizing a model plasticized poly(vinyl) chloride (PVC), N-diazeniumdiolate system and looking at the adsorption of fibrinogen, an important clotting protein, to these surfaces. The materials have been prepared in such a way to eliminate changes in surface properties between the control (plasticized PVC) and composite (NO-releasing) materials. This allows us to isolate NO release and determine the effect on the adsorption of fibrinogen, to the material surface. Surprisingly, it was found that an NO releasing material with a surface flux of 17.4 ± 0.5 × 10(-10) mol NO cm(-2) min(-1) showed a significant increase in the amount of fibrinogen adsorbed to the material surface compared to one with a flux of 13.0 ± 1.6 × 10(-10) mol NO cm(-2) min(-1) and the control (2334 ± 496, 226 ± 99, and 103 ±31% fibrinogen adsorbed of control, respectively). This study suggests that NO's role in controlling clotting is extended beyond platelet activation. PMID:23554300

  17. Synthesis of arsenic graft adsorbents in pilot scale

    NASA Astrophysics Data System (ADS)

    Hoshina, Hiroyuki; Kasai, Noboru; Shibata, Takuya; Aketagawa, Yasushi; Takahashi, Makikatsu; Yoshii, Akihiro; Tsunoda, Yasuhiko; Seko, Noriaki

    2012-08-01

    Synthesis of arsenic (As) adsorbents in pilot scale was carried out with a synthesizing apparatus by radiation-induced graft polymerization of 2-hydroxyethyl methacrylate phosphoric acid monomer (PA), which consists of phosphoric acid mono- (50%) and di- (50%) ethyl methacrylate esters onto a nonwoven cotton fabric (NCF), and following chemical modification by contact with a zirconium (Zr) solution. The apparatus which was equipped with reaction tanks, a washing tank and a pump can produce up to 0.3 m×14 m size of the As(V) adsorbent in one reaction. A degree of grafting of 150% was obtained at an irradiation dose of 20 kGy with 5% of PA solution mixed with deionized water for 1 h at 40 °C. Finally, after Zr(IV) was loaded onto a NCF with 5 mmol/L of Zr(IV) solution, the graft adsorbent for the removal of As(V) was achieved in pilot-scale. The adsorbent which was synthesized in pilot scale was evaluated in batch mode adsorption with 1 ppm (mg/l) of As(V) solution for 2 h at room temperature. As a result, the adsorption capacity for As(V) was 0.02 mmol/g-adsorbent.

  18. Interlocking order parameter fluctuations in structural transitions between adsorbed polymer phases.

    PubMed

    Martins, Paulo H L; Bachmann, Michael

    2016-01-21

    By means of contact-density chain-growth simulations of a simple coarse-grained lattice model for a polymer grafted at a solid homogeneous substrate, we investigate the complementary behavior of the numbers of surface-monomer and monomer-monomer contacts under various solvent and thermal conditions. This pair of contact numbers represents an appropriate set of order parameters that enables the distinct discrimination of significantly different compact phases of polymer adsorption. Depending on the transition scenario, these order parameters can interlock in perfect cooperation. The analysis helps understand the transitions from compact filmlike adsorbed polymer conformations into layered morphologies and dissolved adsorbed structures, respectively, in more detail. PMID:26690091

  19. [Evaluation of voriconazole oral dosage in Japan].

    PubMed

    Hamada, Yukihiro; Kawasumi, Noriyo; Hirai, Jun; Yamagishi, Yuka; Mikamo, Hiroshige

    2014-10-01

    Voriconazole (VRCZ), a broad-spectrum triazole, is served in two dosage forms-injection and oral. VRCZ is difference dosage of oral and intravenous administration writing a medical package insert in Japan. 6 mg/kg intravenous injection (IV) twice daily for first day as initial loading dose, followed by 3-4 mg/kg IV twice daily between meals is recommended. 300 mg orally twice daily for first day as initial loading dose, followed by 150-200 mg orally twice daily between meals is recommended. Patients weighing over 40 kg, 200 mg orally twice daily between meals is recommended. Patients weighing under 40 kg, 100 mg orally twice daily between meals is recommended, increase to 150 mg twice daily if inadequate response. This study evaluated VRCZ trough concentration and oral dosage in the 23 cases which administered VRCZ to analysis for TDM in Aichi University Hospital. Spearman rank correlation coefficient was calculated to examine relationships among variables. The level of statistical significance was set at p=0.05. All data were analyzed and processed on JMP 8 (SAS Institute Japan). There was a significant positive correlation between VRCZ trough concentration and dose/weight (r=0.47 p<0.05). In this result, VRCZ oral dosage is appropriate to administer dose/weight (mg/kg) twice a day as same as IV. PMID:25566590

  20. Conformational changes of adsorbed proteins

    NASA Astrophysics Data System (ADS)

    Allen, Scott

    2005-03-01

    The adsorption of bovine serum albumin (BSA) and pepsin to gold surfaces has been studied using surface plasmon resonance (SPR). Proteins are adsorbed from solution onto a gold surface and changes in the conformation of the adsorbed proteins are induced by changing the buffer solution. We selected pH and ionic strength values for the buffer solutions that are known from our circular dichroism measurements to cause conformational changes of the proteins in bulk solution. We find that for both BSA and pepsin the changes in conformation are impeded by the interaction of the protein with the gold surface.

  1. Electrical contact resistance degradation of a hot-switched simulated metal MEMS contact.

    SciTech Connect

    Dugger, Michael Thomas; Dickrell, Daniel John, III

    2005-03-01

    Electrical contact resistance testing was performed by hot-switching a simulated gold-platinum metal microelectromechanical systems contact. The experimental objective was to determine the sensitivity of the contact resistance degradation to current level and environment. The contact resistance increased sharply after 100 hot-switched cycles in air. Hot-switching at a reduced current and in nitrogen atmosphere curtailed contact resistance degradation by several orders of magnitude. The mechanism responsible for the resistance degradation was found to be arc-induced decomposition of adsorbed surface contaminants.

  2. Desorption of uranium recovered with fibrous amidoxime adsorbent shaped into balls

    SciTech Connect

    Kusakabe, Katsuki; Isumi, Noriaki; Morooka, Shigeharu )

    1994-07-01

    Amidoxime fiber synthesized with a commercial PAN fiber was packed in 2 cm-diameter spherical shells made of plastic net. The adsorbent balls were then packed in a cage through which seawater passed. This shape of adsorbent increased the contact efficiency between adsorbent and seawater but might decrease the desorption rate of uranium adsorbed in the balls. The rate of desorption from 2 cm-diameter adsorbent balls packed in a column was nearly equal to the value obtained with completely dispersed amidoxime fiber, however, when the eluent velocity through the balls was higher than 2-4 cm[center dot]s[sup [minus]1] and the void fraction in the balls was higher than 0.8. Most of the liquid held in the balls was removed with a light centrifugation. 11 refs., 4 figs., 1 tab.

  3. Higher unit dosage of psychotropic drugs.

    PubMed

    Burrell, C D

    1975-12-01

    The realities of the marketplace dictate that pharmaceutical companies seek to develop higher unit dosage forms. Technical problems not infrequently hinder such development. In low doses once-a-day medication with psychotropics is possible and practical. The potential for adverse reactions frequently renders it desirable to divide higher daily doses into two separate doses, one given in the morning and the other in the evening. PMID:1233527

  4. Study of dosage compensation in Drosophila.

    PubMed Central

    Chiang, Pei-Wen; Kurnit, David M

    2003-01-01

    Using a sensitive RT-QPCR assay, we analyzed the regulatory effects of sex and different dosage compensation mutations in Drosophila. To validate the assay, we showed that regulation for several genes indeed varied with the number of functional copies of that gene. We then confirmed that dosage compensation occurred for most genes we examined in male and female flies. Finally, we examined the effects on regulation of several genes in the MSL pathway, presumed to be involved in sex-dependent determination of regulation. Rather than seeing global alterations of either X chromosomal or autosomal genes, regulation of genes on either the X chromosome or the autosomes could be elevated, depressed, or unaltered between sexes in unpredictable ways for the various MSL mutations. Relative dosage for a given gene between the sexes could vary at different developmental times. Autosomal genes often showed deranged regulatory levels, indicating they were in pathways perturbed by X chromosomal changes. As exemplified by the BR-C locus and its dependent Sgs genes, multiple genes in a given pathway could exhibit coordinate regulatory modulation. The variegated pattern shown for expression of both X chromosomal and autosomal loci underscores the complexity of gene expression so that the phenotype of MSL mutations does not reflect only simple perturbations of genes on the X chromosome. PMID:14668373

  5. Extraction of palladium from acidic solutions with the use of carbon adsorbents

    SciTech Connect

    O.N. Kononova; N.G. Goryaeva; N.B. Dostovalova; S.V. Kachin; A.G. Kholmogorov

    2007-08-15

    We studied the sorption of palladium(II) on LKAU-4, LKAU-7, and BAU carbon adsorbents from model hydrochloric acid solutions and the solutions of spent palladium-containing catalysts. It was found that sorbents based on charcoal (BAU) and anthracite (LKAU-4) were characterized by high sorption capacities for palladium. The kinetics of the saturation of carbon adsorbents with palladium(II) ions was studied, and it was found that more than 60% of the initial amount of Pd(II) was recovered in a 1-h contact of an adsorbent with a model solution. This value for the solutions of spent catalysts was higher than 35%.

  6. Estimated Maximal Safe Dosages of Tumescent Lidocaine

    PubMed Central

    Jeske, Daniel R.

    2016-01-01

    BACKGROUND: Tumescent lidocaine anesthesia consists of subcutaneous injection of relatively large volumes (up to 4 L or more) of dilute lidocaine (≤1 g/L) and epinephrine (≤1 mg/L). Although tumescent lidocaine anesthesia is used for an increasing variety of surgical procedures, the maximum safe dosage is unknown. Our primary aim in this study was to measure serum lidocaine concentrations after subcutaneous administration of tumescent lidocaine with and without liposuction. Our hypotheses were that even with large doses (i.e., >30 mg/kg), serum lidocaine concentrations would be below levels associated with mild toxicity and that the concentration-time profile would be lower after liposuction than without liposuction. METHODS: Volunteers participated in 1 to 2 infiltration studies without liposuction and then one study with tumescent liposuction totally by local anesthesia. Serum lidocaine concentrations were measured at 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, and 24 hours after each tumescent lidocaine infiltration. Area under the curve (AUC∞) of the serum lidocaine concentration-time profiles and peak serum lidocaine concentrations (Cmax) were determined with and without liposuction. For any given milligram per kilogram dosage, the probability that Cmax >6 μg/mL, the threshold for mild lidocaine toxicity was estimated using tolerance interval analysis. RESULTS: In 41 tumescent infiltration procedures among 14 volunteer subjects, tumescent lidocaine dosages ranged from 19.2 to 52 mg/kg. Measured serum lidocaine concentrations were all <6 μg/mL over the 24-hour study period. AUC∞s with liposuction were significantly less than those without liposuction (P = 0.001). The estimated risk of lidocaine toxicity without liposuction at a dose of 28 mg/kg and with liposuction at a dose of 45 mg/kg was ≤1 per 2000. CONCLUSIONS: Preliminary estimates for maximum safe dosages of tumescent lidocaine are 28 mg/kg without liposuction and 45 mg/kg with liposuction. As a

  7. The density and refractive index of adsorbing protein layers.

    PubMed

    Vörös, Janos

    2004-07-01

    The structure of the adsorbing layers of native and denatured proteins (fibrinogen, gamma-immunoglobulin, albumin, and lysozyme) was studied on hydrophilic TiO(2) and hydrophobic Teflon-AF surfaces using the quartz crystal microbalance with dissipation and optical waveguide lightmode spectroscopy techniques. The density and the refractive index of the adsorbing protein layers could be determined from the complementary information provided by the two in situ instruments. The observed density and refractive index changes during the protein-adsorption process indicated the presence of conformational changes (e.g., partial unfolding) in general, especially upon contact with the hydrophobic surface. The structure of the formed layers was found to depend on the size of the proteins and on the experimental conditions. On the TiO(2) surface smaller proteins formed a denser layer than larger ones and the layer of unfolded proteins was less dense than that adsorbed from the native conformation. The hydrophobic surface induced denaturation and resulted in the formation of thin compact protein films of albumin and lysozyme. A linear correlation was found between the quartz crystal microbalance measured dissipation factor and the total water content of the layer, suggesting the existence of a dissipative process that is related to the solvent molecules present inside the adsorbed protein layer. Our measurements indicated that water and solvent molecules not only influence the 3D structure of proteins in solution but also play a crucial role in their adsorption onto surfaces. PMID:15240488

  8. Supercritical fluid regeneration of adsorbents

    NASA Astrophysics Data System (ADS)

    Defilippi, R. P.; Robey, R. J.

    1983-05-01

    The results of a program to perform studies supercritical (fluid) carbon dioxide (SCF CO2) regeneration of adsorbents, using samples of industrial wastewaters from manufacturing pesticides and synthetic solution, and to estimate the economics of the specific wastewater treatment regenerations, based on test data are given. Processing costs for regenerating granular activated carbon GAC) for treating industrial wastewaters depend on stream properties and regeneration throughput.

  9. Robust Maleimide-Functionalized Gold Surfaces and Nanoparticles Generated Using Custom-Designed Bidentate Adsorbates.

    PubMed

    Park, Chul Soon; Lee, Han Ju; Jamison, Andrew C; Lee, T Randall

    2016-07-26

    A series of custom-designed alkanethioacetate ligands were synthesized to provide a facile method of attaching maleimide-terminated adsorbates to gold nanostructures via thiolate bonds. Monolayers on flat gold substrates derived from both mono- and dithioacetates, with and without oligo(ethylene glycol) (OEG) moieties in their alkyl spacers, were characterized using X-ray photoelectron spectroscopy, polarization modulation infrared reflection-absorption spectroscopy, ellipsometry, and contact angle goniometry. For all adsorbates, the resulting monolayers revealed that a higher packing density and more homogeneous surface were generated when the film was formed in EtOH, but a higher percentage of bound thiolate was obtained in THF. A series of gold nanoparticles (AuNPs) capped with each adsorbate were prepared to explore how adsorbate structure influences aqueous colloidal stability under extreme conditions, as examined visually and spectroscopically. The AuNPs coated with adsorbates that include OEG moieties exhibited enhanced stability under high salt concentration, and AuNPs capped with dithioacetate adsorbates exhibited improved stability against ligand exchange in competition with dithiothreitol (DTT). Overall, the best results were obtained with a chelating dithioacetate adsorbate that included OEG moieties in its alkyl spacer, imparting improved stability via enhanced solubility in water and superior adsorbate attachment owing to the chelate effect. PMID:27385466

  10. Uptake of uranium from seawater by amidoxime-based polymeric adsorbent marine testing

    SciTech Connect

    Tsouris, C.; Kim, J.; Oyola, Y.; Mayes, R.; Hexel, C.; Sostre Gonzalez, F.; Janke, C.; Dai, S.; Gill, G.; Kuo, L.J.; Wood, J.; Choe, K.Y.; Pourmand, A.; D'Alessandro, E.; Buesseler, K.; Pike, S.

    2013-07-01

    Amidoxime-based polymer adsorbents in the form of functionalized fibers were prepared at the Oak Ridge National Laboratory (ORNL) and screened in laboratory experiments, in terms of uranium uptake capacity, using spiked uranium solution and seawater samples. Batch laboratory experiments conducted with 5-gallon seawater tanks provided equilibrium information. Based on results from 5-gallon experiments, the best adsorbent was selected for field-testing of uranium adsorption from seawater. Flow-through column tests have been performed at different marine sites to investigate the uranium uptake rate and equilibrium capacity under diverse biogeochemistry. The maximum amount of uranium uptake from seawater tests at Sequim, WA, was 3.3 mg U/g adsorbent after eight weeks of contact of the adsorbent with seawater. This amount was three times higher than the maximum adsorption capacity achieved in this study by a leading adsorbent developed by the Japan Atomic Energy Agency (JAEA), which was 1.1 mg U/g adsorbent at equilibrium. The initial uranium uptake rate of the ORNL adsorbent was 2.6 times higher than that of the JAEA adsorbent under similar conditions. A mathematical model derived from the mass balance of uranium was employed to describe the data. (authors)

  11. Alcohol, aggression and assertiveness in men: dosage and expectancy effects.

    PubMed

    Kreutzer, J S; Schneider, H G; Myatt, C R

    1984-05-01

    The effect of alcohol on aggression and assertiveness was examined in 54 men college students. A 2 (high vs low dosage expectancy) x 3 (0.0, 0.5 and 1.0 ml of 95% alcohol per kg of body weight) design was used. There was an increase in self-reported aggression at the moderate dosage but an increase only in profanity at the high dosage. The expectancy manipulation also produced an increase in self-reported aggression. Actual dosage and dosage expectancy did not influence assertiveness. PMID:6748671

  12. Method And Apparatus For Regenerating Nox Adsorbers

    DOEpatents

    Driscoll, J. Joshua; Endicott, Dennis L.; Faulkner, Stephen A.; Verkiel, Maarten

    2006-03-28

    Methods and apparatuses for regenerating a NOx adsorber coupled with an exhaust of an engine. An actuator drives a throttle valve to a first position when regeneration of the NOx adsorber is desired. The first position is a position that causes the regeneration of the NOx adsorber. An actuator drives the throttle valve to a second position while regeneration of the NOx adsorber is still desired. The second position being a position that is more open than the first position and operable to regenerate a NOx adsorber.

  13. Evaluation of new indomethacin dosage forms.

    PubMed

    Waller, E S

    1983-01-01

    Indomethacin, an indole derivative nonsteroidal anti-inflammatory drug, has been available since the early 1960s in gelatin capsules. In 1982, a sustained release product, Indocin SR, was marketed. Awaiting marketing approval is a unique controlled release form of indomethacin, Indos. The disposition of indomethacin includes enterohepatic cycling and extensive metabolism to inactive metabolites. Enterohepatic cycling makes interpretation of bioavailability estimates of indomethacin dosage forms difficult. The relationship of indomethacin plasma concentration to therapeutic effects and side effects is inconclusive. It appears in vivo prostaglandin inhibition occurs at very low plasma concentrations that are achievable with all available dosage forms. Indocin SR is a sustained release capsule of indomethacin designed to deliver 25 mg of drug immediately and 50 mg gradually. Absolute bioavailability of the product is 80%. The plasma concentration-time curves do not show good sustained release characteristics; after four hours plasma concentrations resemble those seen with a single dose of regular capsule. The cost compared with Indocin is competitive. Indos is a zero-order release form of indomethacin. It is a unique drug delivery system that shows good controlled release characteristics. Bioavailability is 85%. Both Indocin SR and Indos are apparently therapeutically equivalent to indomethacin capsules. In elderly patients, Indos has been shown to be associated with fewer side effects than Indocin. Both Indocin SR and Indos have the advantage of once or twice daily dosing. PMID:6361702

  14. Bioavailability of valsartan oral dosage forms.

    PubMed

    Sunkara, Gangadhar; Bende, Girish; Mendonza, Anisha E; Solar-Yohay, Susan; Biswal, Shibadas; Neelakantham, Srikanth; Wagner, Robert; Flarakos, Jimmy; Zhang, Yiming; Jarugula, Venkateswar

    2014-03-01

    The oral bioavailability of valsartan from extemporaneous suspension and solution formulations were evaluated relative to tablet formulation in two separate open-label, randomized crossover studies in healthy adults. In both studies, the plasma concentrations of valsartan after oral administration were analyzed using validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods, and the corresponding pharmacokinetic parameters were estimated using noncompartmental analysis. The peak plasma concentration (Cmax ) and area under the concentration time-curves (AUC(0-∞) ) of valsartan from the extemporaneous suspension were higher by 1.93- and 1.56-fold, respectively, relative to the tablet formulation (P < .001). The Cmax and AUC(0-∞) of valsartan from the oral solution were higher by 2.21- and 1.74-fold, respectively, relative to the tablet formulation (P < .001). These results indicate that both rate and extent of absorption of valsartan are higher in the two liquid dosage forms (extemporaneous suspension and solution formulations) relative to the solid oral dosage form (tablet formulation). PMID:27128457

  15. 3,5-Dichlorophenol Removal From Wastewater Using Alternative Adsorbents

    NASA Astrophysics Data System (ADS)

    Kobetičová, Hana; Lipovský, Marek; Wachter, Igor; Soldán, Maroš

    2015-06-01

    The main objective of this paper is to evaluate the efficiency of 3,5-dichlorophenol removal from wastewater by using alternative low cost adsorbents. Waste from the production and processing of metals (black nickel mud, red mud) and a biosorbent (Lemna minor) were used for this research. Initial concentration of the contaminant was 4 mmol L-1, the contact time of sorbent and waste water was 0 - 48 hrs and the temperature during experiment was 25 ± 0.2 °C. The results show that the highest removal efficiency of 3,5 - dichlorophenol (58.18 %) was reached by the red mud in 48 hours.

  16. Effect of adsorbed chlorine and oxygen on shear strength of iron and copper junctions

    NASA Technical Reports Server (NTRS)

    Wheeler, D. R.

    1975-01-01

    Static friction experiments were performed in ultrahigh vacuum at room temperature on copper, iron, and steel contacts selectively contaminated with oxygen and chlorine in submonolayer amounts. The concentration of the adsorbates was determined with Auger electron spectroscopy and was measured relative to the saturation concentration of oxygen on iron (concentration 1.0). The coefficient of static friction decreased with increasing adsorbate concentration. It was independent of the metal and the adsorbate. The results compared satisfactorily with an extension of the junction growth theory to heterogeneous interfaces. The reduction in interfacial shear strength was measured by the ratio sub a/sub m where sub a is the shear strength of the interface with an adsorbate concentration of 1.0, and sub m is the strength of the clean metal interface. This ratio was 0.835 + or - 0.012 for all the systems tested.

  17. X Chromosome and Autosome Dosage Responses in Drosophila melanogaster Heads.

    PubMed

    Chen, Zhen-Xia; Oliver, Brian

    2015-06-01

    X chromosome dosage compensation is required for male viability in Drosophila. Dosage compensation relative to autosomes is two-fold, but this is likely to be due to a combination of homeostatic gene-by-gene regulation and chromosome-wide regulation. We have baseline values for gene-by-gene dosage compensation on autosomes, but not for the X chromosome. Given the evolutionary history of sex chromosomes, these baseline values could differ. We used a series of deficiencies on the X and autosomes, along with mutations in the sex-determination gene transformer-2, to carefully measure the sex-independent X-chromosome response to gene dosage in adult heads by RNA sequencing. We observed modest and indistinguishable dosage compensation for both X chromosome and autosome genes, suggesting that the X chromosome is neither inherently more robust nor sensitive to dosage change. PMID:25850426

  18. A novel fiber-based adsorbent technology

    SciTech Connect

    Reynolds, T.A.

    1997-10-01

    In this Phase I Small Business Innovation Research program, Chemica Technologies, Inc. is developing an economical, robust, fiber-based adsorbent technology for removal of heavy metals from contaminated water. The key innovation is the development of regenerable adsorbent fibers and adsorbent fiber cloths that have high capacity and selectivity for heavy metals and are chemically robust. The process has the potential for widespread use at DOE facilities, mining operations, and the chemical process industry.

  19. Quasiparticle excitations of adsorbates on doped graphene

    NASA Astrophysics Data System (ADS)

    Lischner, Johannes; Wickenburg, Sebastian; Wong, Dillon; Karrasch, Christoph; Wang, Yang; Lu, Jiong; Omrani, Arash A.; Brar, Victor; Tsai, Hsin-Zon; Wu, Qiong; Corsetti, Fabiano; Mostofi, Arash; Kawakami, Roland K.; Moore, Joel; Zettl, Alex; Louie, Steven G.; Crommie, Mike

    Adsorbed atoms and molecules can modify the electronic structure of graphene, but in turn it is also possible to control the properties of adsorbates via the graphene substrate. In my talk, I will discuss the electronic structure of F4-TCNQ molecules on doped graphene and present a first-principles based theory of quasiparticle excitations that captures the interplay of doping-dependent image charge interactions between substrate and adsorbate and electron-electron interaction effects on the molecule. The resulting doping-dependent quasiparticle energies will be compared to experimental scanning tunnelling spectra. Finally, I will also discuss the effects of charged adsorbates on the electronic structure of doped graphene.

  20. Application of longan shell as non-conventional low-cost adsorbent for the removal of cationic dye from aqueous solution

    NASA Astrophysics Data System (ADS)

    Wang, Ya; Zhu, Lin; Jiang, Haitao; Hu, Fang; Shen, Xiangqian

    2016-04-01

    With simple physical treatment, adsorption potential of longan shell for the methylene blue (MB) from aqueous solution was studied as a low-cost material under the conditions of adsorbent dosage (1-6 g/L), initial solution pH (2-12), contact time (5-180 min), temperature (293, 313, 313 K) and initial dye concentration (100-500 mg/L). The SEM images and FTIR spectra of longan shell before and after dye adsorption were analyzed to understand the adsorption process of MB onto longan shell. The kinetic data and the equilibrium data were simulated by different kinetic and isotherm models, respectively. The results showed that the adsorption process was well described by the pseudo-second-order kinetic model, and the experimental equilibrium data were better fit to Langmuir equation than Freundlich equation with the maximum adsorption capacity of 141.04 mg/g. In addition, main activation parameters (Ea, ΔH#, ΔS# and ΔG#) and thermodynamic parameters (ΔG°, ΔH° and ΔS°) of the absorption process were also determined.

  1. Application of longan shell as non-conventional low-cost adsorbent for the removal of cationic dye from aqueous solution.

    PubMed

    Wang, Ya; Zhu, Lin; Jiang, Haitao; Hu, Fang; Shen, Xiangqian

    2016-04-15

    With simple physical treatment, adsorption potential of longan shell for the methylene blue (MB) from aqueous solution was studied as a low-cost material under the conditions of adsorbent dosage (1-6 g/L), initial solution pH (2-12), contact time (5-180 min), temperature (293, 313, 313 K) and initial dye concentration (100-500 mg/L). The SEM images and FTIR spectra of longan shell before and after dye adsorption were analyzed to understand the adsorption process of MB onto longan shell. The kinetic data and the equilibrium data were simulated by different kinetic and isotherm models, respectively. The results showed that the adsorption process was well described by the pseudo-second-order kinetic model, and the experimental equilibrium data were better fit to Langmuir equation than Freundlich equation with the maximum adsorption capacity of 141.04 mg/g. In addition, main activation parameters (E(a), ΔH(#), ΔS(#) and ΔG(#)) and thermodynamic parameters (ΔG°, ΔH° and ΔS°) of the absorption process were also determined. PMID:26878356

  2. Equilibrium, Thermodynamics, and Kinetic Sorption Studies for the Removal of Coomassie Brilliant Blue on Wheat Bran as a Low-Cost Adsorbent

    PubMed Central

    Ata, Sadia; Imran Din, Muhammad; Rasool, Atta; Qasim, Imran; Ul Mohsin, Ijaz

    2012-01-01

    The sorption studies of coomassie brilliant blue (CBB) from aqueous solution have been carried out on wheat bran (WB). Coomassie brilliant blue on wheat bran was used to study the adsorption behavior under various parameters such as pH, dosage amount, and contact time. It was observed that under optimized conditions up to 95.70% dye could be removed from solution onto WB. Langmuir and Freundlich adsorption isotherms were used to elaborate the results. Freundlich model was found to be fitted well and favored multilayer adsorption. The Freundlich constants n and KF were determined as 0.53 and 2.5 × 10−4. Thermodynamic parameters such as ΔG, ΔH, and ΔS studied were taking into account, showed spontaneous and favorable reaction for coomassie brilliant blue on wheat bran. The maximum adsorption capacity qm was found to be 6.410 mg/g. The investigations show that non treated WB is a low-cost adsorbent for the removal of dyes from textile industry effluents. PMID:22567559

  3. Prioritized Contact Transport Stream

    NASA Technical Reports Server (NTRS)

    Hunt, Walter Lee, Jr. (Inventor)

    2015-01-01

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

  4. Types of Contact Lenses

    MedlinePlus

    ... Consumer Devices Consumer Products Contact Lenses Types of Contact Lenses Share Tweet Linkedin Pin it More sharing ... Orthokeratology (Ortho-K) Decorative (Plano) Contact Lenses Soft Contact Lenses Soft contact lenses are made of soft, ...

  5. An effective desiccant system to regulate the humidity inside the chambers of the solid dosage forms.

    PubMed

    Lehto, Vesa-Pekka; Erling, Ida

    2007-11-01

    The most common way to protect moisture-sensitive pharmaceutical powders is to utilize protective packaging. However, the most convenient package materials are all permeable to water molecules to some extent and limited protection is normally achieved with this arrangement even though desiccants are employed. In the present study we introduce a novel system that can regulate the internal humidity of the containers used with solid dosage forms for a desired time at a requested level. Instead of the widely used solid adsorbents the system utilizes saturated salt solutions loaded in desiccant bags made of various polymer materials with appropriate permeation properties. By utilizing salt solutions the size of the desiccant bag can be further reduced. A wide variety of commonly used powder chambers and desiccant bags are tested, proving the effectiveness of the introduced system. PMID:18058320

  6. The uranium from seawater program at PNNL: Overview of marine testing, adsorbent characterization, adsorbent durability, adsorbent toxicity, and deployment studies

    DOE PAGESBeta

    Gill, Gary A.; Kuo, Li -Jung; Janke, Christopher James; Park, Jiyeon; Jeters, Robert T.; Bonheyo, George T.; Pan, Horng -Bin; Wai, Chien; Khangaonkar, Tarang P.; Bianucci, Laura; et al

    2016-02-07

    The Pacific Northwest National Laboratory's (PNNL) Marine Science Laboratory (MSL) located along the coast of Washington State is evaluating the performance of uranium adsorption materials being developed for seawater extraction under realistic marine conditions with natural seawater. Two types of exposure systems were employed in this program: flow-through columns for testing of fixed beds of individual fibers and pellets and a recirculating water flume for testing of braided adsorbent material. Testing consists of measurements of the adsorption of uranium and other elements from seawater as a function of time, typically 42 to 56 day exposures, to determine the adsorbent capacitymore » and adsorption rate (kinetics). Analysis of uranium and other trace elements collected by the adsorbents was conducted following strong acid digestion of the adsorbent with 50% aqua regia using either Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) or Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The ORNL 38H adsorbent had a 56 day adsorption capacity of 3.30 ± 0.68 g U/ kg adsorbent (normalized to a salinity of 35 psu), a saturation adsorption capacity of 4.89 ± 0.83 g U/kg of adsorbent material (normalized to a salinity of 35 psu) and a half-saturation time of 28 10 days. The AF1 adsorbent material had a 56 day adsorption capacity of 3.9 ± 0.2 g U/kg adsorbent material (normalized to a salinity of 35 psu), a saturation capacity of 5.4 ± 0.2 g U/kg adsorbent material (normalized to a salinity of 35 psu) and a half saturation time of 23 2 days. The ORNL amidoxime-based adsorbent materials are not specific for uranium, but also adsorb other elements from seawater. The major doubly charged cations in seawater (Ca and Mg) account for a majority of the cations adsorbed (61% by mass and 74% by molar percent). For the ORNL AF1 adsorbent material, U is the 4th most abundant element adsorbed by mass and 7th most abundant by molar percentage. Marine testing

  7. The Uranium from Seawater Program at PNNL: Overview of marine testing, adsorbent characterization, adsorbent durability, adsorbent toxicity, and deployment studies

    SciTech Connect

    Gill, Gary; Kuo, Li-Jung; Janke, Christopher James; Park, Jiyeon; Jeters, Robert T; Bonheyo, George; Pan, Horng-Bin; Wai, Chien; Khangaonkar, Tarang P; Bianucci, Laura; Wood, Jordana; Warner, Marvin G; Peterson, Sonja; Abrecht, David; Mayes, Richard T; Tsouris, Costas; Oyola, Yatsandra; Strivens, Jonathan E.; Schlafer, Nicholas; Addleman, Shane R; Chouyyok, Wilaiwan; Das, Sadananda; Kim, Jungseung; Buesseler, Dr. Ken; Breier, Crystalline; D'Alessandro, Dr. Evan

    2016-01-01

    The Pacific Northwest National Laboratory s (PNNL) Marine Science Laboratory (MSL) located along the coast of Washington State is evaluating the performance of uranium adsorption materials being developed for seawater extraction under realistic marine conditions with natural seawater. Two types of exposure systems were employed in this program: flow-through columns for testing of fixed beds of individual fibers and pellets and a recirculating water flume for testing of braided adsorbent material. Testing consists of measurements of the adsorption of uranium and other elements from seawater as a function of time, typically 42 to 56 day exposures, to determine the adsorbent capacity and adsorption rate (kinetics). Analysis of uranium and other trace elements collected by the adsorbents was conducted following strong acid digestion of the adsorbent with 50% aqua regia using either Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) or Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The ORNL 38H adsorbent had a 56 day adsorption capacity of 3.30 0.68 g U/ kg adsorbent (normalized to a salinity of 35 psu), a saturation adsorption capacity of 4.89 0.83 g U/kg of adsorbent material (normalized to a salinity of 35 psu) and a half-saturation time of 28 10 days. The AF1 adsorbent material had a 56 day adsorption capacity of 3.9 0.2 g U/kg adsorbent material (normalized to a salinity of 35 psu), a saturation capacity of 5.4 0.2 g U/kg adsorbent material (normalized to a salinity of 35 psu) and a half saturation time of 23 2 days. The ORNL amidoxime-based adsorbent materials are not specific for uranium, but also adsorb other elements from seawater. The major doubly charged cations in seawater (Ca and Mg) account for a majority of the cations adsorbed (61% by mass and 74% by molar percent). For the ORNL AF1 adsorbent material, U is the 4th most abundant element adsorbed by mass and 7th most abundant by molar percentage. Marine testing at Woods Hole

  8. [Reexaminations of dosages in Shanghanlun: comparison of the dosages among decoctions, pills and powder formulations].

    PubMed

    Suzuki, Tatsuhiko; Endo, Jiro

    2011-01-01

    This paper reveals the dosages of decoctions in Shanghanlun in relation of pills and powder formulations, and obtains following results. At the first examination of the system of weight, while Taohongjing shows three kinds of system of weight; [(1)1liang is equivalent to 14 g. (2) 1liang = 7 g (3) 1liang = 1.4 g], he describes the necessity of the corrective system of weight among the decoctions, the pills and the powder formulations. After Song dynasty, Zhusanfa, which is the method of preparing the decoction by placing powder ingredients of prescriptions in water and simmer, have been mainly adopted. In the term of Zhusanfa, although the whole quantities of prescriptions are written with the ancient weight unit, the notation of the dosage is indicated by the current weight unit, Qian. In Shanghanlun, since the dosage form seems to have been changed from the pills or the powders into the decoction, some of decoctions contain impractical dose for decoction. PMID:21796994

  9. Complete braided adsorbent for marine testing to demonstrate 3g-U/kg-adsorbent

    SciTech Connect

    Janke, Chris; Yatsandra, Oyola; Mayes, Richard; none,; Gill, Gary; Li-Jung, Kuo; Wood, Jordana; Sadananda, Das

    2014-04-30

    ORNL has manufactured four braided adsorbents that successfully demonstrated uranium adsorption capacities ranging from 3.0-3.6 g-U/kg-adsorbent in marine testing at PNNL. Four new braided and leno woven fabric adsorbents have also been prepared by ORNL and are currently undergoing marine testing at PNNL.

  10. Fluorescence dynamics of microsphere-adsorbed sunscreens

    NASA Astrophysics Data System (ADS)

    Krishnan, R.

    2005-03-01

    Sunscreens are generally oily substances which are prepared in organic solvents, emulsions or dispersions with micro- or nanoparticles. These molecules adsorb to and integrate into skin cells. In order to understand the photophysical properties of the sunscreen, we compare steady-state and time-resolved fluorescence in organic solvent of varying dielectric constant ɛ and adsorbed to polystyrene microspheres and dispersed in water. Steady-state fluorescence is highest and average fluorescence lifetime longest in toluene, the solvent of lowest ɛ. However, there is no uniform dependence on ɛ. Sunscreens PABA and padimate-O show complex emission spectra. Microsphere-adsorbed sunscreens exhibit highly non-exponential decay, illustrative of multiple environments of the adsorbed molecule. The heterogeneous fluorescence dynamics likely characterizes sunscreen adsorbed to cells.

  11. Nanovalved Adsorbents for CH4 Storage.

    PubMed

    Song, Zhuonan; Nambo, Apolo; Tate, Kirby L; Bao, Ainan; Zhu, Minqi; Jasinski, Jacek B; Zhou, Shaojun J; Meyer, Howard S; Carreon, Moises A; Li, Shiguang; Yu, Miao

    2016-05-11

    A novel concept of utilizing nanoporous coatings as effective nanovalves on microporous adsorbents was developed for high capacity natural gas storage at low storage pressure. The work reported here for the first time presents the concept of nanovalved adsorbents capable of sealing high pressure CH4 inside the adsorbents and storing it at low pressure. Traditional natural gas storage tanks are thick and heavy, which makes them expensive to manufacture and highly energy-consuming to carry around. Our design uses unique adsorbent pellets with nanoscale pores surrounded by a coating that functions as a valve to help manage the pressure of the gas and facilitate more efficient storage and transportation. We expect this new concept will result in a lighter, more affordable product with increased storage capacity. The nanovalved adsorbent concept demonstrated here can be potentially extended for the storage of other important gas molecules targeted for diverse relevant functional applications. PMID:27124722

  12. NOx adsorber and method of regenerating same

    SciTech Connect

    Endicott, Dennis L.; Verkiel, Maarten; Driscoll, James J.

    2007-01-30

    New technologies, such as NOx adsorber catalytic converters, are being used to meet increasingly stringent regulations on undesirable emissions, including NOx emissions. NOx adsorbers must be periodically regenerated, which requires an increased fuel consumption. The present disclosure includes a method of regenerating a NOx adsorber within a NOx adsorber catalytic converter. At least one sensor positioned downstream from the NOx adsorber senses, in the downstream exhaust, at least one of NOx, nitrous oxide and ammonia concentrations a plurality of times during a regeneration phase. The sensor is in communication with an electronic control module that includes a regeneration monitoring algorithm operable to end the regeneration phase when a time rate of change of the at least one of NOx, nitrous oxide and ammonia concentrations is after an expected plateau region begins.

  13. Uptake of Uranium from Seawater by Amidoxime-Based Polymeric Adsorbent: Field Experiments, Modeling, and Updated Economic Assessment

    SciTech Connect

    Kim, Jungseung; Tsouris, Constantinos; Oyola, Yatsandra; Janke, C.; Mayes, R. T.; Dai, Sheng; Gill, Gary A.; Kuo, Li-Jung; Wood, Jordana R.; Choe, Key-Young; Schneider, Erich; Lindner, Harry

    2014-04-09

    Uranium recovery from seawater has been investigated for several decades for the purpose of securing nuclear fuel for energy production. In this study, field column experiments have been performed at the Marine Sciences Laboratory of the Pacific Northwest National Laboratory (PNNL) using a laboratory-proven, amidoxime-based polymeric adsorbent developed at the Oak Ridge National Laboratory (ORNL). The adsorbent was packed either in in-line filters or in flow-through columns. The maximum amount of uranium uptake from seawater was 3.3 mg of U/g of adsorbent after 8 weeks of contact between the adsorbent and seawater. This uranium adsorption amount was about 3 times higher than the maximum amount achieved in this study by a leading adsorbent developed at the Japan Atomic Energy Agency (JAEA).

  14. Defluoridation of groundwater using brick powder as an adsorbent.

    PubMed

    Yadav, Asheesh Kumar; Kaushik, C P; Haritash, Anil Kumar; Kansal, Ankur; Rani, Neetu

    2006-02-01

    Defluoridation of groundwater using brick powder as an adsorbent was studied in batch process. Different parameters of adsorption, viz. effect of pH, effect of dose and contact time were selected and optimized for the study. Feasible optimum conditions were applied to two groundwater samples of high fluoride concentration to study the suitability of adsorbent in field conditions. Comparison of adsorption by brick powder was made with adsorption by commercially available activated charcoal. In the optimum condition of pH and dose of adsorbents, the percentage defluoridation from synthetic sample, increased from 29.8 to 54.4% for brick powder and from 47.6 to 80.4% for commercially available activated charcoal with increasing the contact time starting from 15 to 120 min. Fluoride removal was found to be 48.73 and 56.4% from groundwater samples having 3.14 and 1.21 mg l(-1) fluoride, respectively, under the optimized conditions. Presence of other ions in samples did not significantly affect the deflouridation efficiency of brick powder. The optimum pH range for brick powder was found to be 6.0-8.0 and adsorption equilibrium was found to be 60 min. These conditions make it very suitable for use in drinking water treatment. Deflouridation capacity of brick powder can be explained on the basis of the chemical interaction of fluoride with the metal oxides under suitable pH conditions. The adsorption process was found to follow first order rate mechanism as well as Freundlich isotherm. PMID:16233952

  15. 21 CFR 520.540 - Dexamethasone oral dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Dexamethasone oral dosage forms. 520.540 Section 520.540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Dexamethasone oral dosage forms....

  16. 21 CFR 520.88 - Amoxicillin oral dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Amoxicillin oral dosage forms. 520.88 Section 520.88 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.88 Amoxicillin...

  17. 21 CFR 520.2325 - Sulfaquinoxaline oral dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sulfaquinoxaline oral dosage forms. 520.2325 Section 520.2325 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Sulfaquinoxaline oral dosage forms....

  18. 21 CFR 520.2325 - Sulfaquinoxaline oral dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sulfaquinoxaline oral dosage forms. 520.2325 Section 520.2325 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Sulfaquinoxaline oral dosage forms....

  19. 21 CFR 520.1044 - Gentamicin sulfate oral dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Gentamicin sulfate oral dosage forms. 520.1044 Section 520.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1044...

  20. 21 CFR 520.1044 - Gentamicin sulfate oral dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Gentamicin sulfate oral dosage forms. 520.1044 Section 520.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1044...

  1. 21 CFR 520.1044 - Gentamicin sulfate oral dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Gentamicin sulfate oral dosage forms. 520.1044 Section 520.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1044...

  2. 21 CFR 520.1044 - Gentamicin sulfate oral dosage forms.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Gentamicin sulfate oral dosage forms. 520.1044 Section 520.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1044...

  3. 21 CFR 520.1044 - Gentamicin sulfate oral dosage forms.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Gentamicin sulfate oral dosage forms. 520.1044 Section 520.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1044...

  4. Problem solved: dosage calculation in a nursing program.

    PubMed

    Jackson, Nancy V; De Carlo, James J

    2011-01-01

    Patient safety, including the safe administration of medications, is an essential component of nursing practice. However, helping students calculate medication dosages has continually challenged faculty members and students. The authors describe a comprehensive approach to teaching and evaluating dosage calculation. Common barriers to helping students master necessary math skills required for accuracy are addressed. PMID:21330900

  5. 21 CFR 520.763 - Dithiazanine iodide oral dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Dithiazanine iodide oral dosage forms. 520.763 Section 520.763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Dithiazanine iodide oral dosage forms....

  6. 21 CFR 520.540 - Dexamethasone oral dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Dexamethasone oral dosage forms. 520.540 Section 520.540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Dexamethasone oral dosage forms....

  7. 21 CFR 520.540 - Dexamethasone oral dosage forms.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Dexamethasone oral dosage forms. 520.540 Section 520.540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Dexamethasone oral dosage forms....

  8. 21 CFR 520.540 - Dexamethasone oral dosage forms.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Dexamethasone oral dosage forms. 520.540 Section 520.540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Dexamethasone oral dosage forms....

  9. 21 CFR 520.540 - Dexamethasone oral dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Dexamethasone oral dosage forms. 520.540 Section 520.540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Dexamethasone oral dosage forms....

  10. 21 CFR 520.2345 - Tetracycline oral dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Tetracycline oral dosage forms. 520.2345 Section 520.2345 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Tetracycline oral dosage forms....

  11. 21 CFR 520.88 - Amoxicillin oral dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Amoxicillin oral dosage forms. 520.88 Section 520.88 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.88 Amoxicillin...

  12. 21 CFR 520.88 - Amoxicillin oral dosage forms.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Amoxicillin oral dosage forms. 520.88 Section 520.88 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.88 Amoxicillin...

  13. 21 CFR 520.88 - Amoxicillin oral dosage forms.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Amoxicillin oral dosage forms. 520.88 Section 520.88 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.88 Amoxicillin...

  14. 21 CFR 520.88 - Amoxicillin oral dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Amoxicillin oral dosage forms. 520.88 Section 520.88 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.88 Amoxicillin...

  15. 21 CFR 520.390 - Chloramphenicol oral dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Chloramphenicol oral dosage forms. 520.390 Section 520.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Chloramphenicol oral dosage forms....

  16. 21 CFR 520.390 - Chloramphenicol oral dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Chloramphenicol oral dosage forms. 520.390 Section 520.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Chloramphenicol oral dosage forms....

  17. 21 CFR 520.390 - Chloramphenicol oral dosage forms.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Chloramphenicol oral dosage forms. 520.390 Section 520.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Chloramphenicol oral dosage forms....

  18. 21 CFR 520.390 - Chloramphenicol oral dosage forms.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Chloramphenicol oral dosage forms. 520.390 Section 520.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Chloramphenicol oral dosage forms....

  19. 21 CFR 520.390 - Chloramphenicol oral dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Chloramphenicol oral dosage forms. 520.390 Section 520.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Chloramphenicol oral dosage forms....

  20. 21 CFR 522.1222 - Ketamine hydrochloride injectable dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Ketamine hydrochloride injectable dosage forms. 522.1222 Section 522.1222 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... ANIMAL DRUGS § 522.1222 Ketamine hydrochloride injectable dosage forms....

  1. 21 CFR 522.1222 - Ketamine hydrochloride injectable dosage forms.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Ketamine hydrochloride injectable dosage forms. 522.1222 Section 522.1222 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... ANIMAL DRUGS § 522.1222 Ketamine hydrochloride injectable dosage forms....

  2. 21 CFR 522.1222 - Ketamine hydrochloride injectable dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Ketamine hydrochloride injectable dosage forms. 522.1222 Section 522.1222 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... ANIMAL DRUGS § 522.1222 Ketamine hydrochloride injectable dosage forms....

  3. 21 CFR 520.1696 - Penicillin oral dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Penicillin oral dosage forms. 520.1696 Section 520.1696 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1696 Penicillin...

  4. 21 CFR 526.1696 - Penicillin intramammary dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Penicillin intramammary dosage forms. 526.1696 Section 526.1696 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS INTRAMAMMARY DOSAGE FORMS § 526.1696...

  5. 21 CFR 526.1696 - Penicillin intramammary dosage forms.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Penicillin intramammary dosage forms. 526.1696 Section 526.1696 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Penicillin intramammary dosage forms....

  6. 21 CFR 526.1696 - Penicillin intramammary dosage forms.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Penicillin intramammary dosage forms. 526.1696 Section 526.1696 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Penicillin intramammary dosage forms....

  7. 21 CFR 520.1696 - Penicillin oral dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Penicillin oral dosage forms. 520.1696 Section 520.1696 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1696 Penicillin...

  8. 21 CFR 526.1696 - Penicillin intramammary dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Penicillin intramammary dosage forms. 526.1696 Section 526.1696 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Penicillin intramammary dosage forms....

  9. 21 CFR 526.1696 - Penicillin intramammary dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Penicillin intramammary dosage forms. 526.1696 Section 526.1696 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Penicillin intramammary dosage forms....

  10. 21 CFR 520.1696 - Penicillin oral dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Penicillin oral dosage forms. 520.1696 Section 520.1696 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1696 Penicillin...

  11. 21 CFR 522.1222 - Ketamine hydrochloride injectable dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ketamine hydrochloride injectable dosage forms. 522.1222 Section 522.1222 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... ANIMAL DRUGS § 522.1222 Ketamine hydrochloride injectable dosage forms....

  12. 21 CFR 522.313 - Ceftiofur injectable dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ceftiofur injectable dosage forms. 522.313 Section 522.313 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL...

  13. 21 CFR 522.1660 - Oxytetracycline injectable dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Oxytetracycline injectable dosage forms. 522.1660 Section 522.1660 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... § 522.1660 Oxytetracycline injectable dosage forms....

  14. Protection of live bacteria from bile acid toxicity using bile acid adsorbing resins.

    PubMed

    Edwards, Alexander D; Slater, Nigel K H

    2009-06-12

    We previously demonstrated that a dry, room temperature stable formulation of a live bacterial vaccine was highly susceptible to bile, and suggested that this will lead to significant loss of viability of any live bacterial formulation released into the intestine using an enteric coating or capsule. We found that bile and acid tolerance is very rapidly recovered after rehydration with buffer or water, raising the possibility that rehydration in the absence of bile prior to release into the intestine might solve the problem of bile toxicity to dried cells. We describe here a novel formulation that combines extensively studied bile acid adsorbent resins with the dried bacteria, to temporarily adsorb bile acids and allow rehydration and recovery of bile resistance of bacteria in the intestine before release. Tablets containing the bile acid adsorbent cholestyramine release 250-fold more live bacteria when dissolved in a bile solution, compared to control tablets without cholestyramine or with a control resin that does not bind bile acids. We propose that a simple enteric coated oral dosage form containing bile acid adsorbent resins will allow improved live bacterial delivery to the intestine via the oral route, a major step towards room temperature stable, easily administered and distributed vaccine pills and other bacterial therapeutics. PMID:19490986

  15. Stability of dry coated solid dosage forms.

    PubMed

    Kablitz, Caroline Désirée; Urbanetz, Nora Anne

    2009-01-01

    The dry coating process was evaluated in terms of storage stability investigating drug release and agglomeration tendency of the different coated oral dosage forms; hydroxypropyl methylcellulose acetate succinate (HPMCAS) was used with triethylcitrate (TEC) as plasticizer and acetylated monoglyceride (Myvacet) as wetting agent. Talc or colloidal silicon dioxide (Aerosil) was used as anti-tacking agents. In contrast to coating formulations consisting of HPMCAS and Myvacet all formulations containing TEC showed enteric resistance and no agglomeration tendency after preparation. After storage at 10% RH +/- 5% enteric resistance is increased slightly. This increase is more pronounced at 60% RH +/- 5%. The formulations without anti-tacking agents showed higher drug releases after 12 and 24 months due to the damage of the film's integrity during sample preparation caused by the high tackiness of the film. Tackiness is not affected by storing if samples are stored at low relative humidity. At high relative humidity tackiness increases upon storage especially for formulations without anti-tacking agents. The sieving results of the agglomeration measurements after storage can be confirmed by ring shear measurements performed immediately after preparation and approved to be a tool, which is able to predict the agglomeration during storage. PMID:19883250

  16. Separation of the attractive and repulsive contributions to the adsorbate-adsorbate interactions of polar adsorbates on Si(100)

    NASA Astrophysics Data System (ADS)

    Lin, Ying-Hsiu; Jeng, Horng-Tay; Lin, Deng-Sung

    2015-11-01

    Dissociative adsorption of H2O, NH3, CH3OH and CH3NH2 polar molecules on the Si(100) surface results in a 1:1 mixture of two adsorbates (H and multi-atomic fragment A = OH, NH2, CH3O, CH3NH, respectively) on the surface. By using density functional theory (DFT) calculations, the adsorption geometry, the total energies and the charge densities for various possible ordered structures of the mixed adsorbate layer have been found. Analyzing the systematic trends in the total energies unveils concurrently the nearest-neighbor interactions ENN and the next nearest-neighbor interactions ENNN between two polar adsorbates A. In going from small to large polar adsorbates, ENN's exhibit an attractive-to-repulsive crossover behavior, indicating that they include competing attractive and repulsive contributions. Exploration of the charge density distributions allows the estimation of the degree of charge overlapping between immediately neighboring A's, the resulting contribution of the steric repulsions, and that of the attractive interactions to the corresponding ENN's. The attractive contributions to nearest neighboring adsorbate-adsorbate interactions between the polar adsorbates under study are shown to result from hydrogen bonds or dipole-dipole interactions.

  17. Analysis of Adsorbate-Adsorbate and Adsorbate-Adsorbent Interactions to Decode Isosteric Heats of Gas Adsorption.

    PubMed

    Madani, S Hadi; Sedghi, Saeid; Biggs, Mark J; Pendleton, Phillip

    2015-12-21

    A qualitative interpretation is proposed to interpret isosteric heats of adsorption by considering contributions from three general classes of interaction energy: fluid-fluid heat, fluid-solid heat, and fluid-high-energy site (HES) heat. Multiple temperature adsorption isotherms are defined for nitrogen, T=(75, 77, 79) K, argon at T=(85, 87, 89) K, and for water and methanol at T=(278, 288, 298) K on a well-characterized polymer-based, activated carbon. Nitrogen and argon are subjected to isosteric heat analyses; their zero filling isosteric heats of adsorption are consistent with slit-pore, adsorption energy enhancement modelling. Water adsorbs entirely via specific interactions, offering decreasing isosteric heat at low pore filling followed by a constant heat slightly in excess of water condensation enthalpy, demonstrating the effects of micropores. Methanol offers both specific adsorption via the alcohol group and non-specific interactions via its methyl group; the isosteric heat increases at low pore filling, indicating the predominance of non-specific interactions. PMID:26538339

  18. Inorganic chemically active adsorbents (ICAAs)

    SciTech Connect

    Ally, M.R.; Tavlarides, L.

    1997-10-01

    Oak Ridge National Laboratory (ORNL) researchers are developing a technology that combines metal chelation extraction technology and synthesis chemistry. They begin with a ceramic substrate such as alumina, titanium oxide or silica gel because they provide high surface area, high mechanical strength, and radiolytic stability. One preparation method involves silylation to hydrophobize the surface, followed by chemisorption of a suitable chelation agent using vapor deposition. Another route attaches newly designed chelating agents through covalent bonding by the use of coupling agents. These approaches provide stable and selective, inorganic chemically active adsorbents (ICAAs) tailored for removal of metals. The technology has the following advantages over ion exchange: (1) higher mechanical strength, (2) higher resistance to radiation fields, (3) higher selectivity for the desired metal ion, (4) no cation exchange, (5) reduced or no interference from accompanying anions, (6) faster kinetics, and (7) easy and selective regeneration. Target waste streams include metal-containing groundwater/process wastewater at ORNL`s Y-12 Plant (multiple metals), Savannah River Site (SRS), Rocky Flats (multiple metals), and Hanford; aqueous mixed wastes at Idaho National Engineering Laboratory (INEL); and scrubber water generated at SRS and INEL. Focus Areas that will benefit from this research include Mixed Waste, and Subsurface Contaminants.

  19. Chitosan, nanoclay and chitosan-nanoclay composite as adsorbents for Rhodamine-6G and the resulting optical properties.

    PubMed

    Vanamudan, Ageetha; Pamidimukkala, Padmaja

    2015-03-01

    The objective of this study was to investigate the use of chitosan-clay nanocomposite (CC) as an adsorbent for Rhodamine 6G (Rh-6G). The effects of adsorbent dose, contact time, and concentration on the adsorption process were systematically studied. Isotherm models were applied to the experimental equilibrium data obtained from spectrophotometric measurements of dye adsorption. Various Kinetic models were used to describe the kinetic data and evaluate of rate constants. Rh-6G loaded adsorbents were investigated for their optical and photophysical properties. PMID:25526692

  20. The preparation of polyelectrolyte complexes carboxymethyl chitosan(CMC)-pectin by reflux method as a Pb (II) metal ion adsorbent

    NASA Astrophysics Data System (ADS)

    Hastuti, Budi; Mudasir, Siswanta, Dwi; Triyono

    2016-02-01

    Aim of this research is to synthesized a chemically stable polyelectrolyte complexs carboxymetyl chitosan CMC-pectin as Pb(II) ion adsorbent by reflux method. During synthesis process, the optimum mass ratio of CMC and pectin was pre-determined and the active groups of the CMC-pectin complex was characterized by using IR spectrofotometer. Finally, adsorption capacity of the adsorbent material for Pb (II) ions was studied under optimum condition, i.e. adsorbent mass, contact time, and pH. Result shows that CMC could be succesfully combined with pectin to produce CMC-pectin complex. The optimum mass ratio CMC: pectin to form the polyelectrolyte complexs CMC-pectin was 70% : 30%. The active groups identified in the CMC-pectin complex was a hydroxyl (OH) and carboxylate (-COOH) groups. The optimum conditions for Pb (II) ion absoprtion was 10 mg of the adsorbent mass, 75 min of contact time, and pH 5. This material can be effectively used as adsorbents for Pb (II) ions, where up to 91% Pb (II) metal ions was adsorbed from aqueous solution and the adsorption capacity of the adsorbent was 41.63 mg/g.

  1. Low-cost magnetic adsorbent for As(III) removal from water: adsorption kinetics and isotherms.

    PubMed

    Kango, Sarita; Kumar, Rajesh

    2016-01-01

    Magnetite nanoparticles as adsorbent for arsenic (As) were coated on sand particles. The coated sand was used for the removal of highly toxic element 'As(III)' from drinking water. Here, batch experiments were performed with the variation of solution pH, adsorbent dose, contact time and initial arsenic concentration. The adsorbent showed significant removal efficiency around 99.6 % for As(III). Analysis of adsorption kinetics revealed that the adsorbent follows pseudo-second-order kinetics model showing R (2) = 0.999, whereas for pseudo-first-order kinetics model, the value of R (2) was 0.978. In the case of adsorption equilibrium, the data is well fitted with Langmuir adsorption isotherm model (R (2) > 0.99), indicating monolayer adsorption of As(III) on the surface of adsorbent. The existence of commonly present ions in water influences the removal efficiency of As(III) minutely in the following order PO4 (3-) > HCO3 (-) > Cl(-) > SO4 (2-). The obtained adsorbent can be used to overcome the problem of water filtration in rural areas. Moreover, as the nano-magnetite is coated on the sand, it avoids the problem of extraction of nanoparticles from treated water and can easily be removed by a simple filtration process. PMID:26711813

  2. 2-chlorophenol sorption from aqueous solution using granular activated carbon and polymeric adsorbents

    NASA Astrophysics Data System (ADS)

    Ghatbandhe, A. S.; Jahagirdar, H. G.; Yenkie, M. K. N.; Deosarkar, S. D.

    2013-08-01

    Adsorption equilibrium and kinetics of 2-chlorophenol (2-CP) one of the chlorophenols (CPs) onto bituminous coal based Filtrasorb-400 grade granular activated carbon and three different types of polymeric adsorbents were studied in aqueous solution in a batch system. Langmuir isotherm models were applied to experimental equilibrium data of 2-CP adsorption. Equilibrium data fitted very well to the Langmuir equilibrium models of 2-CP. Adsorbent monolayer capacity Q Langmuir constant b and adsorption rate constants k a were evaluated. 2-CP adsorption using GAC is very rapid in the first hour of contact where 70-80% of the adsorbate is removed by GAC followed by a slow approach to equilibrium. Whereas in case of polymeric adsorbents 60-65% of the adsorbate is removed in the first 30 min which is then followed by a slow approach to equilibrium. The order of adsorption of 2-CP on different adsorbents used in the study is found to be in following order: F-400 > XAD-1180 > XAD-4 > XAD-7HP.

  3. Site blocking effects on adsorbed polyacrylamide conformation

    NASA Astrophysics Data System (ADS)

    Brotherson, Brett A.

    The use of polymers as flocculating additives is a common practice in many manufacturing environments. However, exactly how these polymers interact with surfaces is relatively unknown. One specific topic which is thought to be very important to flocculation is an adsorbed polymer's conformation. Substantial amounts of previous work, mainly using simulations, have been performed to elucidate the theory surrounding adsorbed polymer conformations. Yet, there is little experimental work which directly verifies current theory. In order to optimize the use of polymer flocculants in industrial applications, a better understanding of an adsorbed polymer's conformation on a surface beyond theoretical simulations is necessary. This work looks specifically at site blocking, which has a broad impact on flocculation, adsorption, and surface modification, and investigated its effects on the resulting adsorbed polymer conformation. Experimental methods which would allow direct determination of adsorbed polymer conformational details and be comparable with previous experimental results were first determined or developed. Characterization of an adsorbed polymer's conformation was then evaluated using dynamic light scattering, a currently accepted experimental technique to examine this. This commonly used technique was performed to allow the comparison of this works results with past literature. Next, a new technique using atomic force microscopy was developed, building on previous experimental techniques, to allow the direct determination of an adsorbed polymer's loop lengths. This method also was able to quantify changes in the length of adsorbed polymer tails. Finally, mesoscopic simulation was attempted using dissipative particle dynamics. In order to determine more information about an adsorbed polymer's conformation, three different environmental factors were analyzed: an adsorbed polymer on a surface in water, an adsorbed polymer on a surface in aqueous solutions of varying

  4. Adsorbed natural gas storage with activated carbon

    SciTech Connect

    Sun, Jian; Brady, T.A.; Rood, M.J.

    1996-12-31

    Despite technical advances to reduce air pollution emissions, motor vehicles still account for 30 to 70% emissions of all urban air pollutants. The Clean Air Act Amendments of 1990 require 100 cities in the United States to reduce the amount of their smog within 5 to 15 years. Hence, auto emissions, the major cause of smog, must be reduced 30 to 60% by 1998. Natural gas con be combusted with less pollutant emissions. Adsorbed natural gas (ANG) uses adsorbents and operates with a low storage pressure which results in lower capital costs and maintenance. This paper describes the production of an activated carbon adsorbent produced from an Illinois coal for ANG.

  5. States of water adsorbed on perindopril crystals

    NASA Astrophysics Data System (ADS)

    Stepanov, V. A.; Khmelevskaya, V. S.; Bogdanov, N. Yu.; Gorchakov, K. A.

    2011-10-01

    The relationship between the structural state of adsorbed water, the crystal structure of the substances, and the solubility of the perindopril salt C19H32N2O5 · C4H11N in water was studied by IR spectroscopy and X-ray diffractometry. The high-frequency shift of the stretching vibrations of adsorbed water and the solubility depend on the crystal structure of the drug substance. A reversible chemical reaction occurred between the adsorbed water and the perindopril salt.

  6. Rupture force of adsorbed self-assembled surfactant layers. Effect of the dielectric exchange force

    NASA Astrophysics Data System (ADS)

    Teschke, O.; Ceotto, G.; de Souza, E. F.

    2001-08-01

    The tip applied force necessary to obtain tip/substrate contact, i.e., rupture force between adsorbed layers of self-assembled surfactant films and atomic force microscope (AFM) tips in water has been measured. A substantial contribution of this rupture force is due to the dielectric exchange force (DEF). The DEF model is in agreement with the observation that the surfactant layer rupture forces are smaller in the thickest layers, where the compactness of the adsorbed film results in the smallest values of the dielectric permittivity. Within experimental accuracy a dielectric permittivity value of ˜4 for bilayers and of ˜36 for monolayers is found.

  7. Aminophylline Dosage In Asthma Exacerbations in Children: A Systematic Review

    PubMed Central

    2016-01-01

    Background Adequate asthma treatment of childhood exacerbations with IV aminophylline depends on appropriate dosage. Recommendations to aim for a target therapeutic range may be inappropriate as serum concentrations correlate poorly with clinical improvement. This review aims to evaluate the evidence for the optimum dosage strategy of intravenous aminophylline in children suffering an exacerbation of asthma. Methods A systematic review comparing dosage regimens of intravenous aminophylline in children suffering an exacerbation of asthma. Primary outcomes were time until resolution of symptoms, mortality and need for mechanical ventilation. Secondary outcomes were date until discharge criteria are met, actual discharge and adverse effects. Data sources CENTRAL, CINAHL, MEDLINE and Web of Science. Search performed in March 2016 Eligibility criteria Studies using intravenous aminophylline in children with an acute exacerbation of asthma which reported the dosage and clinical outcomes. Findings 14 RCTs were included. There is a poor relationship between the dosage administered to children and symptom resolution, length of stay or need for mechanical ventilation. This study is limited due to its use of indirect evidence. Conclusion The currently recommended dosage regimens may not represent the optimum safety and efficacy of intravenous aminophylline. There is a need to develop the evidence base correlating dosage with patient centered clinical outcomes, to improve prescribing practices. PMID:27483163

  8. Gene dosage effects on the synthesis of maltase in yeast.

    PubMed Central

    Mowshowitz, D B

    1979-01-01

    Inbred strains of Saccharomyces cerevisiae carrying MAL1, MAL2, or MAL6 in a common background were used to construct (i) homo- or heterozygous diploids carrying one or two active alleles of a single MAL locus (MAL1, MAL2, or MAL6) and (ii) triploids carrying one, two, or three active alleles of MAL2. The diploid and triploid strains were used to investigate gene dosage effects of the differential rate of maltase synthesis (delta enzyme activity/delta growth) and the kinetics of induction (for MAL2). All three MAL loci exhibited a gene dosage effect on the differential rate of maltase synthesis; MAL2 also exhibited a gene dosage effect on the kinetics of induction. The dosage effects of the MAL1 and MAL6 loci were additive, but the effects of the MAL2 locus were not; the magnitude of the MAL2 gene dosage effect decreased with increasing dosage. These results are compatible with the current genetic evidence that the MAL genes are regulatory loci if the product(s) of the MAL1 and MAL6 locus is produced in limiting amounts but the product(s) of the MAL2 locus is produced in excess, except at very low genes dosages. PMID:374342

  9. EDITORIAL: Close contact Close contact

    NASA Astrophysics Data System (ADS)

    Demming, Anna

    2010-07-01

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

  10. Crusted scabies and multiple dosages of ivermectin.

    PubMed

    Ortega-Loayza, Alex G; McCall, Calvin O; Nunley, Julia R

    2013-05-01

    We present the case of a bone marrow transplant patient who was diagnosed with crusted scabies but did not respond to the usual approach with topical permethrin and ivermectin. The Centers for Disease Control and Prevention were contacted and suggested a 7-dose regimen of ivermectin. The patient started to improve remarkably after the third dose, and the skin eruption was resolved after 7 doses. This case supports the use of a more prolonged course of oral ivermectin for crusted scabies in those who fail the conventional approach. PMID:23652958

  11. Extending the market exclusivity of therapeutic antibodies through dosage patents.

    PubMed

    Storz, Ulrich

    2016-07-01

    Dosage patents are one way to extend the market exclusivity of an approved drug beyond the lifetime of the patent that protects the drug as such. Dosage patents may help to compensate the applicant for the long period where the active pharmaceutical ingredient as such is already under patent prosecution, but not on the market yet, due to lengthy development and approval procedures. This situation erodes part of the time the drug is marketed under patent protection. Dosage patents filed at a later date can provide remedy for this problem. Examples of successful and unsuccesful attempts, and the reasons for the respective outcomes, are provided in this article. PMID:27115842

  12. Contact micromechanics in granular media with clay

    SciTech Connect

    Ita, S.L.

    1994-08-01

    Many granular materials, including sedimentary rocks and soils, contain clay particles in the pores, grain contacts, or matrix. The amount and location of the clays and fluids can influence the mechanical and hydraulic properties of the granular material. This research investigated the mechanical effects of clay at grain-to-grain contacts in the presence of different fluids. Laboratory seismic wave propagation tests were conducted at ultrasonic frequencies using spherical glass beads coated with Montmorillonite clay (SWy-1) onto which different fluids were adsorbed. For all bead samples, seismic velocity increased and attenuation decreased as the contact stiffnesses increased with increasing stress demonstrating that grain contacts control seismic transmission in poorly consolidated and unconsolidated granular material. Coating the beads with clay added stiffness and introduced viscosity to the mechanical contact properties that increased the velocity and attenuation of the propagating seismic wave. Clay-fluid interactions were studied by allowing the clay coating to absorb water, ethyl alcohol, and hexadecane. Increasing water amounts initially increased seismic attenuation due to clay swelling at the contacts. Attenuation decreased for higher water amounts where the clay exceeded the plastic limit and was forced from the contact areas into the surrounding open pore space during sample consolidation. This work investigates how clay located at grain contacts affects the micromechanical, particularly seismic, behavior of granular materials. The need for this work is shown by a review of the effects of clays on seismic wave propagation, laboratory measurements of attenuation in granular media, and proposed mechanisms for attenuation in granular media.

  13. IR investigations of surfaces and adsorbates

    SciTech Connect

    Gwyn Williams

    2001-12-10

    Synchrotron infrared reflection-absorption measurements on single crystal metal surfaces with adsorbates have led to the determination of many key parameters related to the bonding vibrational modes and the dynamics of adsorbates. In particular, energy couplings between electrons and adsorbate motion have been shown to be a dominant mechanism on metal surfaces. Excellent agreement has been obtained with calculations for many of the observations, and the synergy between theory and experiment has led to a deeper understanding of the roles of electrons and phonons in determining the properties of interfaces and their roles in phenomena as diverse as friction, lubrication, catalysis and adhesion. Nonetheless, as the experiments are pushed harder, to describe such effects as co-adsorbed systems, disagreements continue to challenge the theory and our comprehension also is still evolving.

  14. PERVAPORATION USING ADSORBENT-FILLED MEMBRANES

    EPA Science Inventory

    Membranes containing selective fillers, such as zeolites and activated carbon, can improve the separation by pervaporation. Applications of adsorbent-filled membranes in pervaporation have been demonstrated by a number of studies. These applications include removal of organic co...

  15. Selective LPCVD tungsten for contact barrier applications

    SciTech Connect

    Levy, R.A.; Green, M.L.; Gallagher, P.K.; Ali, Y.S.

    1986-09-01

    This study assesses the use of selective LPCVD tungsten as a contact barrier in VLSI circuits. Measurements of the contact resistance and leakage current are evaluated as a function of variations in W deposition parameters, implant type, implant dosage, and metallization heat-treatment. Addition of SiF/sub 4/ to alter the equilibrium of the displacement reaction is seen to cause minimal erosion and encroachment of the Si contacts as well as produce low and thermally stable contact resistance to both n/sup +/ and p/sup +/ diffusions. For surface doping concentrations of 1.44 x 10/sup 20/ cm/sup -3/ As and 0.62 x 10/sup 20/ cm/sup -3/B, measured values for the contact resistance for 2.0 ..mu..m sized vias are near 30..cap omega... Such values are quite compatible with high performance CMOS device requirements. Further reductions in these values are achieved with use of a self-aligned PtSi/W contact barrier metallization. The contact resistance for 2.0 ..mu..m sized vias are, in this case, near 4 and 15..cap omega.. for the n/sup +/ and p/sup +/ diffusions, respectively. Sporadic leakage across shallow n/sup +//P-Tub junctions remains, however, a serious problem associated with this selective LPCVD W process. Understanding the origin of this leakage and eliminating it can lead to numerous applications of this technology in VLSI manufacturing.

  16. Comparative safety of testosterone dosage forms

    PubMed Central

    Layton, J. Bradley; Meier, Christoph R.; Sharpless, Julie L.; Stürmer, Til; Jick, Susan S.; Brookhart, M. Alan

    2015-01-01

    Importance Increases in testosterone use and mixed reports of adverse events have raised concerns about the cardiovascular safety of testosterone. Testosterone is available in several delivery mechanisms with varying pharmacokinetics; injections cause spikes in testosterone levels, while transdermal patches and gels cause more subtle but sustained increases. The comparative cardiovascular safety of gels, injections and patches has not been studied. Objective To determine the comparative cardiovascular safety of testosterone injections, patches, and gels. Design Retrospective cohort study. Setting Administrative claims from a commercially-insured and Medicare population in the United States, and general practitioner records from the United Kingdom, years 2000 – 2012 Participants Adult (18+), male initiators of testosterone patches, gels, or injections following 180 days free of any testosterone use Exposure New initiation of a testosterone dosage form, followed for up to one year Main Outcomes and Measures In- or outpatient medical records, diagnoses, or claims for: cardio- and cerebrovascular events, including myocardial infarction (MI), unstable angina, stroke, composite acute event (MI, unstable angina, or stroke); venous thromboembolism (VTE); mortality, and all-cause hospitalization. Results We identified 431,687 testosterone initiators between the 3 datasets: 36% injection, 9% patch, 55% gel. Medicare had a majority of injection initiators (51%); the US commercially-insured population had majority gel initiators (56%); the United Kingdom had equal proportions of injections and gels (~41%). When compared to gels, injection initiators had higher hazards of CV events (MI, UA, and stroke) (HR=1.26, 95% CI: 1.18–1.35), hospitalization (HR=1.16, 95% CI: 1.13–1.18), and death (HR=1.34, 95% CI: 1.15–1.56), but not VTE (HR=0.92, 95% CI: 0.76–1.11). Patches did not confer increased hazards of CV events compared to gels (HR=1.10, 95% CI: 0.94–1

  17. Dispersed-phase adsorbents for biotechnology applications

    SciTech Connect

    Scott, C.D.

    1987-01-01

    A new type of adsorbent material has been developed in which very small adsorbent particles are entrapped in a hydrocolloidal gel matrix that is formed into small, monodisperse spherical beads. Examples of applications of this type of material include dispersed, hydrous transition metal oxides that can be used for the retention of biocatalysts, such as enzymes, and certain microorganisms or microbial fragments that can be dispersed into the gel matrix to accumulate and isolate various dissolved metals. 7 refs., 2 figs., 2 tabs.

  18. Regenerable activated bauxite adsorbent alkali monitor probe

    DOEpatents

    Lee, Sheldon H. D.

    1992-01-01

    A regenerable activated bauxite adsorber alkali monitor probe for field applications to provide reliable measurement of alkali-vapor concentration in combustion gas with special emphasis on pressurized fluidized-bed combustion (PFBC) off-gas. More particularly, the invention relates to the development of a easily regenerable bauxite adsorbent for use in a method to accurately determine the alkali-vapor content of PFBC exhaust gases.

  19. Hydrophobic Porous Material Adsorbs Small Organic Molecules

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K.; Hickey, Gregory S.

    1994-01-01

    Composite molecular-sieve material has pore structure designed specifically for preferential adsorption of organic molecules for sizes ranging from 3 to 6 angstrom. Design based on principle that contaminant molecules become strongly bound to surface of adsorbent when size of contaminant molecules is nearly same as that of pores in adsorbent. Material used to remove small organic contaminant molecules from vacuum systems or from enclosed gaseous environments like closed-loop life-support systems.

  20. Mesoporous Silica: A Suitable Adsorbent for Amines

    PubMed Central

    2009-01-01

    Mesoporous silica with KIT-6 structure was investigated as a preconcentrating material in chromatographic systems for ammonia and trimethylamine. Its adsorption capacity was compared to that of existing commercial materials, showing its increased adsorption power. In addition, KIT-6 mesoporous silica efficiently adsorbs both gases, while none of the employed commercial adsorbents did. This means that KIT-6 Mesoporous silica may be a good choice for integrated chromatography/gas sensing micro-devices. PMID:20628459

  1. Regenerable activated bauxite adsorbent alkali monitor probe

    DOEpatents

    Lee, S.H.D.

    1992-12-22

    A regenerable activated bauxite adsorber alkali monitor probe for field applications to provide reliable measurement of alkali-vapor concentration in combustion gas with special emphasis on pressurized fluidized-bed combustion (PFBC) off-gas. More particularly, the invention relates to the development of a easily regenerable bauxite adsorbent for use in a method to accurately determine the alkali-vapor content of PFBC exhaust gases. 6 figs.

  2. Printing medicines as orodispersible dosage forms: Effect of substrate on the printed micro-structure.

    PubMed

    Planchette, C; Pichler, H; Wimmer-Teubenbacher, M; Gruber, M; Gruber-Woelfler, H; Mohr, S; Tetyczka, C; Hsiao, W-K; Paudel, A; Roblegg, E; Khinast, J

    2016-07-25

    We present our recent advancements in developing a viable manufacturing process for printed medicine. Our approach involves using a non-contact printing system that incorporates both piezoelectric- and solenoid valve-based inkjet printing technologies, to deliver both active and inactive pharmaceutical materials onto medical-graded orodispersible films. By using two complimentary inkjet technologies, we were able to dispense an extensive range of fluids, from aqueous drug solutions to viscous polymer coating materials. Essentially, we demonstrate printing of a wide range of formulations for patient-ready, orodispersible drug dosage forms, without the risk of drug degradation by ink heating and of substrate damages (by contact printing). In addition, our printing process has been optimized to ensure that the drug doses can be loaded onto the orally dissolvable films without introducing defects, such as holes or tears, while retaining a smooth surface texture that promotes patient adherence and allows for uniform post-coatings. Results show that our platform technology can address key issues in manufacturing orodispersible drug dosage forms and bring us closer to delivering personalized and precision medicine to targeted patient populations. PMID:26541301

  3. Thiophilic adsorbents for RIA and ELISA procedures.

    PubMed

    Oscarsson, S; Chaga, G; Porath, J

    1991-10-25

    Three types of agarose derivatives have been prepared and investigated as adsorbents for radioimmunoassay and ELISA analysis. The analytical systems were evaluated using beta 2 microglobulin as a model. After a competitive reaction between the immunocomponents in solution, the formed immune complexes were adsorbed onto the adsorbent in the presence of 0.5 M potassium sulfate in 0.1 M Tris, pH 7.5. The binding constant between the interaction site on human IgG and the adsorbent 3-(2-pyridylthio)-2-hydroxypropylagarose (Py-S-gel) was determined to be 1.5 x 10(7) M-1 and the binding capacity was 20 mg/ml gel. The immune complex was desorbed by deleting potassium sulfate from the buffer, and only 0.5% of the total applied protein remained after washing the adsorbent with 0.5 M NaOH. The same adsorbent can be used repetitively with different systems. PMID:1940385

  4. Photochemistry of Nitrate Adsorbed on Mineral Dust

    NASA Astrophysics Data System (ADS)

    Gankanda, A.; Grassian, V. H.

    2013-12-01

    Mineral dust particles in the atmosphere are often associated with adsorbed nitrate from heterogeneous reactions with nitrogen oxides including HNO3 and NO2. Although nitrate ion is a well-studied chromophore in natural waters, the photochemistry of adsorbed nitrate on mineral dust particles is yet to be fully explored. In this study, wavelength dependence of the photochemistry of adsorbed nitrate on different model components of mineral dust aerosol has been investigated using transmission FTIR spectroscopy. Al2O3, TiO2 and NaY zeolite were used as model systems to represent non-photoactive oxides, photoactive semiconductor oxides and porous materials respectively, present in mineral dust aerosol. In this study, adsorbed nitrate is irradiated with 254 nm, 310 nm and 350 nm narrow band light. In the irradiation with narrow band light, NO2 is the only detectable gas-phase product formed from nitrate adsorbed on Al2O3 and TiO2. The NO2 yield is highest at 310 nm for both Al2O3 and TiO2. Unlike Al2O3 and TiO2, in zeolite, adsorbed nitrate photolysis to nitrite is observed only at 310 nm during narrow band irradiation. Moreover gas phase products were not detected during nitrate photolysis in zeolite at all three wavelengths. The significance of these differences as related to nitrate photochemistry on different mineral dust components will be highlighted.

  5. Partial dosage compensation in Strepsiptera, a sister group of beetles.

    PubMed

    Mahajan, Shivani; Bachtrog, Doris

    2015-02-01

    Sex chromosomes have evolved independently in many different taxa, and so have mechanisms to compensate for expression differences on sex chromosomes in males and females. Different clades have evolved vastly different ways to achieve dosage compensation, including hypertranscription of the single X in male Drosophila, downregulation of both X's in XX Caenorhabditis, or inactivation of one X in female mammals. In the flour beetle Tribolium, the X appears hyperexpressed in both sexes, which might represent the first of two steps to evolve dosage compensation along the paths mammals may have taken (i.e., upregulation of X in both sexes, followed by inactivation of one X in females). Here we test for dosage compensation in Strepsiptera, a sister taxon to beetles. We identify sex-linked chromosomes in Xenos vesparum based on genomic analysis of males and females, and show that its sex chromosome consists of two chromosomal arms in Tribolium: The X chromosome that is shared between Tribolium and Strepsiptera, and another chromosome that is autosomal in Tribolium and another distantly related Strepsiptera species, but sex-linked in X. vesparum. We use RNA-seq (RNA sequencing) to show that dosage compensation along the X of X. vesparum is partial and heterogeneous. In particular, genes that are X-linked in both beetles and Strepsiptera appear fully dosage compensated probably through downregulation in both sexes, whereas genes on the more recently added X segment have evolved only partial dosage compensation. In addition, reanalysis of published RNA-seq data suggests that Tribolium has evolved dosage compensation, without hypertranscribing the X in females. Our results demonstrate that patterns of dosage compensation are highly variable across sex-determination systems and even within species. PMID:25601100

  6. Partial Dosage Compensation in Strepsiptera, a Sister Group of Beetles

    PubMed Central

    Mahajan, Shivani; Bachtrog, Doris

    2015-01-01

    Sex chromosomes have evolved independently in many different taxa, and so have mechanisms to compensate for expression differences on sex chromosomes in males and females. Different clades have evolved vastly different ways to achieve dosage compensation, including hypertranscription of the single X in male Drosophila, downregulation of both X’s in XX Caenorhabditis, or inactivation of one X in female mammals. In the flour beetle Tribolium, the X appears hyperexpressed in both sexes, which might represent the first of two steps to evolve dosage compensation along the paths mammals may have taken (i.e., upregulation of X in both sexes, followed by inactivation of one X in females). Here we test for dosage compensation in Strepsiptera, a sister taxon to beetles. We identify sex-linked chromosomes in Xenos vesparum based on genomic analysis of males and females, and show that its sex chromosome consists of two chromosomal arms in Tribolium: The X chromosome that is shared between Tribolium and Strepsiptera, and another chromosome that is autosomal in Tribolium and another distantly related Strepsiptera species, but sex-linked in X. vesparum. We use RNA-seq (RNA sequencing) to show that dosage compensation along the X of X. vesparum is partial and heterogeneous. In particular, genes that are X-linked in both beetles and Strepsiptera appear fully dosage compensated probably through downregulation in both sexes, whereas genes on the more recently added X segment have evolved only partial dosage compensation. In addition, reanalysis of published RNA-seq data suggests that Tribolium has evolved dosage compensation, without hypertranscribing the X in females. Our results demonstrate that patterns of dosage compensation are highly variable across sex-determination systems and even within species. PMID:25601100

  7. An adsorbent monolith device to augment the removal of uraemic toxins during haemodialysis.

    PubMed

    Sandeman, Susan R; Howell, Carol A; Phillips, Gary J; Zheng, Yishan; Standen, Guy; Pletzenauer, Robert; Davenport, Andrew; Basnayake, Kolitha; Boyd, Owen; Holt, Stephen; Mikhalovsky, Sergey V

    2014-06-01

    Adsorbents designed with porosity which allows the removal of protein bound and high molecular weight uraemic toxins may improve the effectiveness of haemodialysis treatment of chronic kidney disease (CKD). A nanoporous activated carbon monolith prototype designed for direct blood contact was first assessed for its capacity to remove albumin bound marker toxins indoxyl sulphate (IS), p-cresyl sulphate (p-CS) and high molecular weight cytokine interleukin-6 in spiked healthy donor studies. Haemodialysis patient blood samples were then used to measure the presence of these markers in pre- and post-dialysis blood and their removal by adsorbent recirculation of post-dialysis blood samples. Nanopores (20-100 nm) were necessary for marker uraemic toxin removal during in vitro studies. Limited removal of IS and p-CS occurred during haemodialysis, whereas almost complete removal occurred following perfusion through the carbon monoliths suggesting a key role for such adsorbent therapies in CKD patient care. PMID:24573455

  8. Adsorption of phenolic compounds from aqueous solutions using carbon nanoporous adsorbent coated with polymer

    NASA Astrophysics Data System (ADS)

    Anbia, Mansoor; Ghaffari, Arezoo

    2009-09-01

    Phenolic compounds are a widespread class of water pollutants that are known to cause serious human health problems; and the demand for effective adsorbents for the removal of toxic compounds is increasing. In this work adsorption of phenol, resorcinol and p-cresol on mesoporous carbon material (CMK-1) and modified with polyaniline polymer (CMK-1/PANI) has been investigated in attempt to explore the possibility of using nanoporous carbon as an efficient adsorbent for pollutants. It was found that CMK-1/PANI exhibits significant adsorption for phenolic derivatives. Batch adsorption studies were carried out to study the effect of various parameters like adsorbent dose, pH, initial concentration and contact time. From the sorption studies it was observed that the uptake of resorcinol was higher than other phenolic derivatives. Freundlich and Langmuir adsorption isotherms were used to model the equilibrium adsorption data for phenolic compounds.

  9. Bioavailability of intranasal promethazine dosage forms in dogs

    NASA Technical Reports Server (NTRS)

    Ramanathan, R.; Geary, R. S.; Bourne, D. W.; Putcha, L.

    1998-01-01

    Intramuscular promethazine (PMZ) is used aboard the US Space Shuttle to ameliorate symptoms of space motion sickness. Bioavailability after an oral dose of PMZ during space flight is thought to be impaired because of gastrointestinal disturbances associated with weightlessness and space motion sickness. In an attempt to find an alternative dosage form for use in space, we evaluated two intranasal (i.n.) dosage forms of PMZ in dogs for absorption and bioavailability relative to that of an equivalent intramuscular dose. Promethazine (5 mg kg-1) was administered as two intranasal dosage forms and as an intramuscular (i.m.) dose to three dogs in a randomised cross-over design. Serial blood samples were taken and analysed for PMZ concentrations and the absorption and bioavailability of PMZ were calculated for the three dosage forms. PMZ absorption from the carboxymethyl cellulose microsphere i.n. dosage form was more rapid and complete than from the myverol cubic gel formulation or from an i.m. injection. Bioavailability of the microsphere formulation was also greater than that of the gel formulation (AUC 3009 vs 1727 ng h ml-1). The bioavailability of the two i.n. dosage forms (relative to that of the i.m. injection) were 94% (microsphere) and 54% (gel). The i.n. microsphere formulation of PMZ offers great promise as an effective non-invasive alternative for treating space motion sickness due to its rapid absorption and bioavailability equivalent to the i.m. dose.

  10. Insight into the adsorption of PPCPs by porous adsorbents: Effect of the properties of adsorbents and adsorbates.

    PubMed

    Zhu, Zengyin; Xie, Jiawen; Zhang, Mancheng; Zhou, Qing; Liu, Fuqiang

    2016-07-01

    Adsorption is an efficient method for removal of pharmaceuticals and personal care products (PPCPs). Magnetic resins are efficient adsorbents for water treatment and exhibit potential for PPCP removal. In this study, the magnetic hypercrosslinked resin Q100 was used for adsorption of PPCPs. The adsorption behavior of this resin was compared with those of two activated carbons, namely, Norit and F400D. Norit exhibited the fastest adsorption kinetics, followed by Q100. Norit featured a honeycomb shape and long-range ordered pore channels, which facilitated the diffusion of PPCPs. Moreover, the large average pore size of Q100 reduced diffusion resistance. The adsorbed amounts of 11 PPCPs on the three adsorbents increased with increasing adsorbate hydrophobicity. For Q100, a significant linear correlation was observed between the adsorption performance for PPCPs and hydrophobicity (logD value) of adsorbates (R(2) = 0.8951); as such, PPCPs with high logD values (>1.69) could be efficiently removed. Compared with those of Norit and F400D, the adsorption performance of Q100 was less affected by humic acid because of the dominant hydrophobic interaction. Furthermore, Q100 showed improved regeneration performance, which renders it promising for PPCP removal in practical applications. PMID:27131811

  11. Prediction of static contact angles on the basis of molecular forces and adsorption data

    NASA Astrophysics Data System (ADS)

    Diaz, M. Elena; Savage, Michael D.; Cerro, Ramon L.

    2016-08-01

    At a three-phase contact line, a liquid bulk phase is in contact with and coexists with a very thin layer of adsorbed molecules. This adsorbed film in the immediate vicinity of a liquid wedge modifies the balance of forces between the liquid and solid phases such that, when included in the balance of forces, a quantitative relationship emerges between the adsorbed film thickness and the static contact angle. This relationship permits the prediction of static contact angles from molecular forces and equilibrium adsorption data by means of quantities that are physically meaningful and measurable. For n-alkanes on polytetrafluoroethylene, for which there are experimental data available on adsorption and contact angles, our computations show remarkable agreement with the data. The results obtained are an improvement on previously published calculations—particularly for alkanes with a low number of carbon atoms, for which adsorption is significant.

  12. Fly ash adsorbents for multi-cation wastewater treatment

    NASA Astrophysics Data System (ADS)

    Visa, Maria; Isac, Luminita; Duta, Anca

    2012-06-01

    Class "F" fly ash (FA), collected from the Central Heat and Power (CHP) Plant Brasov (Romania), with oxides composition SiO2/Al2O3 over 2.4 proved good adsorbent properties, and was further used for obtaining a new substrate with good adsorption capacity for heavy metals from multi-cation wastewater treatment. Firstly, the new adsorbent was characterized by AFM, XRD, DSC, FTIR and the surface energy was evaluated by contact angle measurements. The experimental data suggested that the new type of substrate is predominant crystalline with highly polar surface. The substrate was used for removing the Pb2+, Cd2+ and Zn2+ cations from mixed solutions. The results show high efficiency and selective adsorption the Pb2+ and Zn2+ cations. The optimized adsorption parameters were further used in thermodynamic and kinetic studies of the adsorption processes. The Langmuir and Freundlich models were used to describe the processes. The pseudo-second order kinetics could well model all the processes, indicating a surface concentration of the adsorption sites with the same order of magnitude as the cation concentrations.

  13. Non-destructive determination of anisotropic mechanical properties of pharmaceutical solid dosage forms.

    PubMed

    Akseli, I; Hancock, B C; Cetinkaya, C

    2009-07-30

    The mechanical property anisotropy of compacts made from four commercially available pharmaceutical excipient powders (microcrystalline cellulose, lactose monohydrate, ascorbic acid, and aspartame) was evaluated. The speed of pressure (longitudinal) waves in the uni-axially compressed cubic compacts of each excipient in the three principle directions was determined using a contact ultrasonic method. Average Young's moduli of each compact in the axial (x) and radial (y and z) directions were characterized. The contact ultrasonic measurements revealed that average Young's modulus values vary with different testing orientations which indicate Young's modulus anisotropy in the compacts. The extent of Young's modulus anisotropy was quantified by using a dimensionless ratio and was found to be significantly different for each material (microcrystalline cellulose>lactose>aspartame>ascorbic acid). It is also observed that using the presented contact method, compacts at high solid fraction (0.857-0.859) could be differentiated than those at the solid fraction of 0.85 in their groups. The presented contact ultrasonic method is an attractive tool since it has the advantages of being sensitive to solid fraction ratio, non-destructive, requiring small amount of material and rapid. It is noteworthy that, since the approach provides insight into the performance of common pharmaceutical materials and fosters increased process knowledge, it can be applied to broaden the understanding of the effect of the mechanical properties on the performance (e.g., disintegration profiles) of solid oral dosage forms. PMID:19426791

  14. Modification of chitosan by swelling and crosslinking using epichlorohydrin as heavy metal Cr (VI) adsorbent in batik industry wastes

    NASA Astrophysics Data System (ADS)

    Hastuti, B.; Masykur, A.; Hadi, S.

    2016-02-01

    Study on chitosan modification by swelling and crosslinking and its application as a selective adsorbent for heavy metals Cr (VI) in batik industry wastes was done. Swelling is intended to improve chitosan porosity, whereas crosslinking is to increase the resistance of chitosan against acid. Natural samples are generally acidic, thus limiting chitosan application as an adsorbent. Modification of chitosan by combining swelling and crosslinking is expected to increase its adsorption capacity in binding heavy metal ions in water. The modified chitosan was later contacted with Cr (VI) to test its adsorption capacity with a variation of pH and contact time. Finally, application of modified chitosan was done in batik industry waste containing Cr (IV). Based on the results, chitosan-ECH 25% (v/v) was the optimum concentration of crosslinker to adsorb Cr (VI) ions. Modified chitosan has a solubility resistance to acids, even though a strong acid. Modification of chitosan also improved its adsorption capacity to Cr (VI) from 74% (pure chitosan) to 89% with contact time 30 min at pH 3. On the application to the batik wastes, the modified chitosan were able to adsorb Cr (IV) up to the level of 5 ppm. Thus, the modified chitosan has a potential to be applied to as an adsorbent of Cr (VI) in batik industry wastes.

  15. Black Molecular Adsorber Coatings for Spaceflight Applications

    NASA Technical Reports Server (NTRS)

    Abraham, Nithin Susan; Hasegawa, Mark Makoto; Straka, Sharon A.

    2014-01-01

    The molecular adsorber coating is a new technology that was developed to mitigate the risk of on-orbit molecular contamination on spaceflight missions. The application of this coating would be ideal near highly sensitive, interior surfaces and instruments that are negatively impacted by outgassed molecules from materials, such as plastics, adhesives, lubricants, epoxies, and other similar compounds. This current, sprayable paint technology is comprised of inorganic white materials made from highly porous zeolite. In addition to good adhesion performance, thermal stability, and adsorptive capability, the molecular adsorber coating offers favorable thermal control characteristics. However, low reflectivity properties, which are typically offered by black thermal control coatings, are desired for some spaceflight applications. For example, black coatings are used on interior surfaces, in particular, on instrument baffles for optical stray light control. Similarly, they are also used within light paths between optical systems, such as telescopes, to absorb light. Recent efforts have been made to transform the white molecular adsorber coating into a black coating with similar adsorptive properties. This result is achieved by optimizing the current formulation with black pigments, while still maintaining its adsorption capability for outgassing control. Different binder to pigment ratios, coating thicknesses, and spray application techniques were explored to develop a black version of the molecular adsorber coating. During the development process, coating performance and adsorption characteristics were studied. The preliminary work performed on black molecular adsorber coatings thus far is very promising. Continued development and testing is necessary for its use on future contamination sensitive spaceflight missions.

  16. Many-body dispersion effects in the binding of adsorbates on metal surfaces

    NASA Astrophysics Data System (ADS)

    Maurer, Reinhard J.; Ruiz, Victor G.; Tkatchenko, Alexandre

    2015-09-01

    A correct description of electronic exchange and correlation effects for molecules in contact with extended (metal) surfaces is a challenging task for first-principles modeling. In this work, we demonstrate the importance of collective van der Waals dispersion effects beyond the pairwise approximation for organic-inorganic systems on the example of atoms, molecules, and nanostructures adsorbed on metals. We use the recently developed many-body dispersion (MBD) approach in the context of density-functional theory [Tkatchenko et al., Phys. Rev. Lett. 108, 236402 (2012) and Ambrosetti et al., J. Chem. Phys. 140, 18A508 (2014)] and assess its ability to correctly describe the binding of adsorbates on metal surfaces. We briefly review the MBD method and highlight its similarities to quantum-chemical approaches to electron correlation in a quasiparticle picture. In particular, we study the binding properties of xenon, 3,4,9,10-perylene-tetracarboxylic acid, and a graphene sheet adsorbed on the Ag(111) surface. Accounting for MBD effects, we are able to describe changes in the anisotropic polarizability tensor, improve the description of adsorbate vibrations, and correctly capture the adsorbate-surface interaction screening. Comparison to other methods and experiment reveals that inclusion of MBD effects improves adsorption energies and geometries, by reducing the overbinding typically found in pairwise additive dispersion-correction approaches.

  17. Catalase-like activity studies of the manganese(II) adsorbed zeolites

    NASA Astrophysics Data System (ADS)

    Ćiçek, Ekrem; Dede, Bülent

    2013-12-01

    Preparation of manganese(II) adsorbed on zeolite 3A, 4A, 5A. AW-300, ammonium Y zeolite, organophilic, molecular sieve and catalase-like enzyme activity of manganese(II) adsorbed zeolites are reported herein. Firstly zeolites are activated at 873 K for two hours before contact manganese(II) ions. In order to observe amount of adsorption, filtration process applied for the solution. The pure zeolites and manganese(II) adsorbed zeolites were analysed by FT-IR. As a result according to the FT-IR spectra, the incorporation of manganese(II) cation into the zeolite structure causes changes in the spectra. These changes are expected particularly in the pseudolattice bands connected with the presence of alumino and silicooxygen tetrahedral rings in the zeolite structure. Furthermore, the catalytic activities of the Mn(II) adsorbed zeolites for the disproportionation of hydrogen peroxide were investigated in the presence of imidazole. The Mn(II) adsorbed zeolites display efficiency in the disproportion reactions of hydrogen peroxide, producing water and dioxygen in catalase-like activity.

  18. Many-body dispersion effects in the binding of adsorbates on metal surfaces.

    PubMed

    Maurer, Reinhard J; Ruiz, Victor G; Tkatchenko, Alexandre

    2015-09-14

    A correct description of electronic exchange and correlation effects for molecules in contact with extended (metal) surfaces is a challenging task for first-principles modeling. In this work, we demonstrate the importance of collective van der Waals dispersion effects beyond the pairwise approximation for organic-inorganic systems on the example of atoms, molecules, and nanostructures adsorbed on metals. We use the recently developed many-body dispersion (MBD) approach in the context of density-functional theory [Tkatchenko et al., Phys. Rev. Lett. 108, 236402 (2012) and Ambrosetti et al., J. Chem. Phys. 140, 18A508 (2014)] and assess its ability to correctly describe the binding of adsorbates on metal surfaces. We briefly review the MBD method and highlight its similarities to quantum-chemical approaches to electron correlation in a quasiparticle picture. In particular, we study the binding properties of xenon, 3,4,9,10-perylene-tetracarboxylic acid, and a graphene sheet adsorbed on the Ag(111) surface. Accounting for MBD effects, we are able to describe changes in the anisotropic polarizability tensor, improve the description of adsorbate vibrations, and correctly capture the adsorbate-surface interaction screening. Comparison to other methods and experiment reveals that inclusion of MBD effects improves adsorption energies and geometries, by reducing the overbinding typically found in pairwise additive dispersion-correction approaches. PMID:26374001

  19. Method for modifying trigger level for adsorber regeneration

    DOEpatents

    Ruth, Michael J.; Cunningham, Michael J.

    2010-05-25

    A method for modifying a NO.sub.x adsorber regeneration triggering variable. Engine operating conditions are monitored until the regeneration triggering variable is met. The adsorber is regenerated and the adsorbtion efficiency of the adsorber is subsequently determined. The regeneration triggering variable is modified to correspond with the decline in adsorber efficiency. The adsorber efficiency may be determined using an empirically predetermined set of values or by using a pair of oxygen sensors to determine the oxygen response delay across the sensors.

  20. Irritant Contact Dermatitis

    MedlinePlus

    ... and rashes clinical tools newsletter | contact Share | Irritant Contact Dermatitis Information for adults A A A This ... severe involvement in the patient's armpit. Overview Irritant contact dermatitis is an inflammatory rash caused by direct ...

  1. Contact Lens Risks

    MedlinePlus

    ... Health and Consumer Devices Consumer Products Contact Lenses Contact Lens Risks Share Tweet Linkedin Pin it More ... redness blurred vision swelling pain Serious Hazards of Contact Lenses Symptoms of eye irritation can indicate a ...

  2. Contact Lens Care

    MedlinePlus

    ... For Consumers Consumer Information by Audience For Women Contact Lens Care Share Tweet Linkedin Pin it More ... 1088, www.fda.gov/medwatch Learn More about Contact Lens Care Other Tips on Contact Lenses Decorative ...

  3. Contact Lens Solution Toxicity

    MedlinePlus

    ... rash and rashes clinical tools newsletter | contact Share | Contact Lens Solution Toxicity Information for adults A A A This image shows a reaction to contact lens solution. The prominent blood vessels and redness ...

  4. Dimensionally Frustrated Diffusion towards Fractal Adsorbers

    NASA Astrophysics Data System (ADS)

    Nair, Pradeep R.; Alam, Muhammad A.

    2007-12-01

    Diffusion towards a fractal adsorber is a well-researched problem with many applications. While the steady-state flux towards such adsorbers is known to be characterized by the fractal dimension (DF) of the surface, the more general problem of time-dependent adsorption kinetics of fractal surfaces remains poorly understood. In this Letter, we show that the time-dependent flux to fractal adsorbers (1

  5. Standoff Spectroscopy of Surface Adsorbed Chemicals

    SciTech Connect

    Van Neste, Charles W; Senesac, Larry R; Thundat, Thomas George

    2009-01-01

    Despite its immediate applications, selective detection of trace quantities of surface adsorbed chemicals, such as explosives, without physically collecting the sample molecules is a challenging task. Standoff spectroscopic techniques offer an ideal method of detecting chemicals without using a sample collection step. Though standoff spectroscopic techniques are capable of providing high selectivity, their demonstrated sensitivities are poor. Here we describe standoff detection of trace quantities of surface adsorbed chemicals using two quantum cascade lasers operated simultaneously, with tunable wavelength windows that match with absorption peaks of the analytes. This standoff method is a variation of photoacoustic spectroscopy, where scattered light from the sample surface is used for exciting acoustic resonance of the detector. We demonstrate a sensitivity of 100 ng/cm{sup 2} and a standoff detection distance of 20 m for surface adsorbed analytes such as explosives and tributyl phosphate.

  6. Desorption-induced recombination-cationization of metal-adsorbate adducts from sulfur precovered Ru(0001)

    NASA Astrophysics Data System (ADS)

    Cocco, R. A.; Tatarchuk, B. J.

    1990-03-01

    Temperature programmed static secondary ion mass spectrometry (TPSS) studies of pyrrole, furan and water on sulfur precovered Ru(0001) reveal significant increases in the coverage corrected adduct yield when these species desorb from the surface in an autocatalytic fashion. This effect has been attributed to an enhancement in the recombination-cationization rate which occurs when sputtered-ruthenium species contact desorbed organics just after leaving the surface. Adsorbates which do not undergo autocatalytic/explosive desorption do not exhibit this effect.

  7. Fabrication of nano Delafossite LiCo{sub 0.5}Fe{sub 0.5}O{sub 2} as the new adsorbent in efficient removal of reactive blue 5 from aqueous solutions

    SciTech Connect

    Khosravi, Iman; Yazdanbakhsh, Mohammad; Eftekhar, Melika; Haddadi, Zohreh

    2013-06-01

    Highlights: ► Fabrication of nano Delafossite LiCo{sub 0.5}Fe{sub 0.5}O{sub 2} by sol–gel method. ► Kinetic study of the adsorption properties. ► Removal of reactive blue 5 (RB5) as a reactive dye by the prepared new nanocatalyst. - Abstract: In this paper, nanoparticles of delafossite-type LiCo{sub 0.5}Fe{sub 0.5}O{sub 2} were prepared by sol–gel method in the presence of maleic acid as a chelating agent. The nanoparticles were characterized using differential thermal analysis, X-ray powder diffraction, Fourier infrared spectroscopy, transmission electron microscope, scanning electron microscopy and scanning tunneling microscopy. The nanoparticles showed the excellent adsorption properties towards reactive dye, reactive blue 5 (RB5). The adsorption studies were carried out at different pH values, various adsorbent dosages and contact time in a batch experiments. The kinetic studies indicate that the removal process obeys the second-order kinetic equation. Also, the isotherm evaluations reveal that the adsorption of RB5 by the nanoparticles follows the Freundlich model.

  8. Homogeneity study of ointment dosage forms by infrared imaging spectroscopy.

    PubMed

    Carneiro, Renato Lajarim; Poppi, Ronei Jesus

    2012-01-25

    Ointment dosage forms are semi-solid preparations intended for local or transdermal delivery of active substances usually for application to the skin and it is important that they present a homogeneous appearance. In this work, a study of the homogeneity of a tacrolimus ointment dosage form was performed using infrared imaging spectroscopy coupled with principal component analysis (PCA) and multivariate curve resolution with alternating least squares (MCR-ALS) to interpret the imaging data. Optical visible microscopy images indicated possible phase separation in the ointment and, based on the results presented by distribution concentration maps from infrared imaging, it was possible to conclude that, in fact, there was phase separation incorporated in the ointment. Thus, infrared imaging spectroscopy associated to PCA and MCR-ALS is demonstrated to be a powerful tool for the development process of ointment dosage forms. PMID:22018891

  9. Design of initial dosage regimen using a programmable calculator.

    PubMed

    Ritschel, W A; Eldon, M A

    1985-07-01

    A programmable calculator procedure for the determination of dosage regimens to achieve desired steady state concentrations is described. The dosage regimen prediction is based on data from the literature on pharmacokinetic parameters of drugs and correction factors specific for the patient's condition, such as renal failure, geriatric patient and congestive heart failure. The program is designed to generate dosage regimens based on desired steady state trough level, desired steady state peak level, desired mean steady state level, or to fluctuate between desired steady state peak and trough levels. The program can be used for I.V. and extravascular route of administration. A detailed program description and user instructions are presented and illustrated by three examples. PMID:3840551

  10. Electric contact phenomena in ultra clean and specifically contaminated systems.

    NASA Technical Reports Server (NTRS)

    Keller, D. V., Jr.

    1972-01-01

    Contact resistance has been used to characterize the processes of physical contact in metallic systems with ultra clean surfaces. The contact resistance versus load curves of iron and two cobalt alloys were used to demonstrate the existence of surface work hardening and interfacial creep during contact as well as the fracture characteristics of an interfacial junction as the load is removed. The presence of an adsorbed film of hydrogen or hydrogen ions on iron completely changes the contact process. A comparison of the contact resistance versus load data for ultra pure iron, an iron-cobalt alloy and a cobalt molybdenum-chromium was used to illustrate the effect of substrate mechanical properties on static adhesion and the ability to convert these data for the estimation of the dynamic coefficient of friction under the particular experimental conditions.

  11. Electric contact phenomena in ultra clean and specifically contaminated systems.

    NASA Technical Reports Server (NTRS)

    Keller, D. V., Jr.

    1971-01-01

    Contact resistance has been used to characterize the processes of physical contact in metallic systems with ultraclean surfaces. The contact resistance versus load curves of iron and two cobalt alloys were used to demonstrate the existence of surface work hardening and interfacial creep during contact as well as the fracture characteristics of an interfacial junction as the load is removed. The presence of an adsorbed film of hydrogen or hydrogen ions on iron completely changes the contact process. A comparison of the contact resistance versus load data for ultrapure iron, and iron-cobalt alloy, and a cobalt molybdenum-chromium was used to illustrate the effect of substrate mechanical properties on static adhesion and the ability to convert these data for the estimation of the dynamic coefficient of friction under the particular experimental conditions.

  12. The biogeochemical cycle of the adsorbed template. II - Selective adsorption of mononucleotides on adsorbed polynucleotide templates

    NASA Technical Reports Server (NTRS)

    Lazard, Daniel; Lahav, Noam; Orenberg, James B.

    1988-01-01

    Experimental results are presented for the verification of the specific interaction step of the 'adsorbed template' biogeochemical cycle, a simple model for a primitive prebiotic replication system. The experimental system consisted of gypsum as the mineral to which an oligonucleotide template attaches (Poly-C or Poly-U) and (5-prime)-AMP, (5-prime)-GMP, (5-prime)-CMP and (5-prime)-UMP as the interacting biomonomers. When Poly-C or Poly-U were used as adsorbed templates, (5-prime)-GMP and (5-prime)-AMP, respectively, were observed to be the most strongly adsorbed species.

  13. Effective removal of Congo red dye from aqueous solution using modified xanthan gum/silica hybrid nanocomposite as adsorbent.

    PubMed

    Ghorai, Soumitra; Sarkar, Amit Kumar; Panda, A B; Pal, Sagar

    2013-09-01

    The aim of this work is to study the feasibility of XG-g-PAM/SiO2 nanocomposite towards its potential application as high performance adsorbent for removal of Congo red (CR) dye from aqueous solution. The surface area, average pore size and total pore volume of the developed nanocomposite has been determined. The efficiency of CR dye adsorption depends on various factors like pH, temperature of the solution, equilibrium time of adsorption, agitation speed, initial concentration of dye and adsorbent dosage. It has been observed that the nanocomposite is having excellent CR dye adsorption capacity (Q0=209.205 mg g(-1)), which is considerably high. The dye adsorption process is controlled by pseudo-second order and intraparticle diffusion kinetic models. The adsorption equilibrium data correlates well with Langmuir isotherm. Desorption study indicates the efficient regeneration ability of the dye loaded nanocomposite. PMID:23896441

  14. Systemic antibody response to nano-size calcium phospate biocompatible adjuvant adsorbed HEV-71 killed vaccine

    PubMed Central

    2015-01-01

    Purpose Since 1980s, human enterovirus-71 virus (HEV-71) is one of the common infectious disease in Asian Pacific region since late 1970s without effective commercial antiviral or protective vaccine is unavailable yet. The work examines the role of vaccine adjuvant particle size and the route of administration on postvaccination antibody response towards HEV-71 vaccine adsorbed to calcium phosphate (CaP) adjuvant. Materials and Methods First, CaP nano-particles were compared to a commercial micro-size and vaccine alone. Secondly, intradermal reduced dosage was compared to the conventional intramuscular immunization. Killed HEV-71 vaccines adsorbed to CaP nano-size (73 nm) and commercial one of micro-size (1.7 µm) were administered through intradermal, intramuscular, rabbits received vaccine alone and unvaccinated animals. Results CaP nano-particles adsorbed HEV-71 vaccine displayed higher antibody than the micro-size or unadsorbed vaccine alone, through both parenteral immunization routes. Moreover, the intradermal route (0.5 µg/mL) of 0.1-mL volume per vaccine dose induced equal IgG antibody level to 1.0-mL intramuscular route (0.5 µg/mL). Conclusion The intradermal vaccine adsorbed CaP nano-adjuvant showed safer and significant antibody response after one-tenth reduced dose quantity (0.5 µg/mL) of only 0.1-mL volume as the most suitable protective, cost effective and affordable formulation not only for HEV-71; but also for developing further effective vaccines toward other human pathogens. PMID:25649429

  15. No X-chromosome dosage compensation in human proteomes.

    PubMed

    Chen, Xiaoshu; Zhang, Jianzhi

    2015-06-01

    The X and Y chromosomes of placental and marsupial mammals originated from a pair of autosomes. Ohno proposed that the expression levels of X-linked genes must have been doubled in males to compensate for the degeneration of their Y homologs. Recent mRNA sequencing experiments, however, found at most weak or infrequent X-chromosome dosage compensation. Nonetheless, dosage compensation need not occur at the mRNA level, because ultimately it is the protein concentration that matters. Analyzing human proteomic data from 22 tissues, we here report that X upregulation is absent at the protein level, indicating that Ohno's hypothesis is also invalid at the protein level. PMID:25697342

  16. Dosage-based parameters for characterization of puff dispersion results.

    PubMed

    Berbekar, Eva; Harms, Frank; Leitl, Bernd

    2015-01-01

    A set of parameters is introduced to characterize the dispersion of puff releases based on the measured dosage. These parameters are the dosage, peak concentration, arrival time, peak time, leaving time, ascent time, descent time and duration. Dimensionless numbers for the scaling of the parameters are derived from dimensional analysis. The dimensionless numbers are tested and confirmed based on a statistically representative wind tunnel dataset. The measurements were carried out in a 1:300 scale model of the Central Business District in Oklahoma City. Additionally, the effect of the release duration on the puff parameters is investigated. PMID:25278155

  17. Estimation of drug dosage regimens with a pharmacokinetic slide rule.

    PubMed

    Straughn, A B; Cruze, C A; Meyer, M C

    1977-02-01

    A pharmacokinetic slide rule to facilitate the computations based on relatively simple pharmacokinetic principles involved in the development of individualized drug dosage regimens is described. The calculations are based on the assumption that the body can be conceived as a one-compartment open model with drug elimination proceeding by apparent first-order kinetics. Examples are presented (1) to illustrate the clinical application of a slide rule to compute the time-course of drug in the body, (2) to calculate steady-state maximum and minimum levels, and accumulation during multiple dosage and (3) to estimate appropriate maintenance doses and intravenous infusion rates. PMID:842548

  18. World-wide radiation dosage calculations for air crew members.

    PubMed

    O'Brien, K; Smart, D F; Shea, M A; Felsberger, E; Schrewe, U; Friedberg, W; Copeland, K

    2003-01-01

    A greatly improved version of the computer program to calculate radiation dosage to air crew members is now available. Designated CARI-6, this program incorporates an updated geomagnetic cutoff rigidity model and a revision of the primary cosmic ray spectrum based on recent work by Gaisser and Stanev (1998). We believe CARI-6 provides the most accurate available method for calculating the radiation dosage to air crew members. The program is now utilized by airline companies around the world and provides unification for subsequent world-wide studies on the effects of natural radiation on aircrew members. PMID:14503487

  19. Unoccupied electronic states in adsorbate systems

    NASA Astrophysics Data System (ADS)

    Bertel, E.

    1991-11-01

    Experimental work on unoccupied electronic states in adsorbate systems on metallic substrates is reviewed with emphasis on recent developments. The first part is devoted to molecular adsorbates. Weakly chemisorbed hydrocarbons are briefly discussed. An exhaustive inverse photoemission (IPE) study of the CO bond to the transition metals Ni, Pb, and Pt is presented. Adsorbed NO is taken as an example to demonstrate the persisting discrepancies in the interpretation of IPE spectra. Atomic adsorbates are discussed in the second part. The quantum well state model is applied to interpret the surface states in reconstructing and non-reconstructing adsorption systems of alkali metals and hydrogen. A recent controversy on the unoccupied electronic states of the Cu(110)/O p(2×1) surface is critically reviewed. The quantum well state model is then compared to tight binding and local-density-functional calculations of the unoccupied bands and the deficiencies of the various approaches are pointed out. Finally, the relation between the surface state model and more chemically oriented models of surface bonding is briefly discussed.

  20. Structure of Non-Equilibrium Adsorbed Polymer Layers

    NASA Astrophysics Data System (ADS)

    O'Shaughnessy, Ben; Vavylonis, Dimitrios

    2004-03-01

    Equilibrium polymer adsorption has been widely studied theoretically. Many experiments however implicate strong non-equilibrium effects for monomer sticking energies somewhat larger than kT, the most common case. The structure and slow dynamics in these layers is not understood. We analyze theoretically non-equilibrium layers from dilute solutions in the limit of irreversible monomer adsorption. We find the density profile ˜ z-4/3 and loop distribution ˜ s-11/5 of the resulting layer are no different to equilibrium. However, single chain statistics are radically different: the layer consists of a flat inner portion of fully collapsed chains plus an outer part whose chains make only fN surface contacts where N is chain length. The contact fractions f follow a broad distribution, P(f) ˜ f-4/5, consistent with experiment [H. M. Schneider et al, Langmuir 12, 994 (1996)], and the lateral size R of adsorbed chains is of order the bulk coil size, R ˜ N^3/5. For equilibrium layers, by contrast, P has a unique peak at a value of f of order unity, while R ˜ N^1/2 is significantly less. The relaxation of a non-equilibrium layer towards equilibrium thus entails chain shrinkage and tighter binding. We speculate that the observed decrease of bulk-layer chain exchange rates with increasing aging reflects these internal layer dynamics.

  1. Development and Testing of Molecular Adsorber Coatings

    NASA Technical Reports Server (NTRS)

    Abraham, Nithin; Hasegawa, Mark; Straka, Sharon

    2012-01-01

    The effect of on-orbit molecular contamination has the potential to degrade the performance of spaceflight hardware and diminish the lifetime of the spacecraft. For example, sensitive surfaces, such as optical surfaces, electronics, detectors, and thermal control surfaces, are vulnerable to the damaging effects of contamination from outgassed materials. The current solution to protect these surfaces is through the use of zeolite coated ceramic adsorber pucks. However, these pucks and its additional complex mounting hardware requirements result in several disadvantages, such as size, weight, and cost related concerns, that impact the spacecraft design and the integration and test schedule. As a result, a new innovative molecular adsorber coating was developed as a sprayable alternative to mitigate the risk of on-orbit molecular contamination. In this study, the formulation for molecular adsorber coatings was optimized using various binders, pigment treatment methods, binder to pigment ratios, thicknesses, and spray application techniques. The formulations that passed coating adhesion and vacuum thermal cycling tests were further tested for its adsorptive capacity. Accelerated molecular capacitance tests were performed in an innovatively designed multi-unit system containing idealized contaminant sources. This novel system significantly increased the productivity of the testing phase for the various formulations that were developed. Work performed during the development and testing phases has demonstrated successful application of molecular adsorber coatings onto metallic substrates, as well as, very promising results for the adhesion performance and the molecular capacitance of the coating. Continued testing will assist in the qualification of molecular adsorber coatings for use on future contamination sensitive spaceflight missions.

  2. 21 CFR 201.55 - Statement of dosage.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 4 2011-04-01 2011-04-01 false Statement of dosage. 201.55 Section 201.55 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL LABELING Labeling Requirements for Prescription Drugs and/or Insulin § 201.55 Statement of...

  3. 21 CFR 201.55 - Statement of dosage.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 4 2013-04-01 2013-04-01 false Statement of dosage. 201.55 Section 201.55 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL LABELING Labeling Requirements for Prescription Drugs and/or Insulin § 201.55 Statement of...

  4. 21 CFR 201.55 - Statement of dosage.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 4 2012-04-01 2012-04-01 false Statement of dosage. 201.55 Section 201.55 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL LABELING Labeling Requirements for Prescription Drugs and/or Insulin § 201.55 Statement of...

  5. 21 CFR 201.55 - Statement of dosage.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Statement of dosage. 201.55 Section 201.55 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL LABELING Labeling Requirements for Prescription Drugs and/or Insulin § 201.55 Statement of...

  6. 21 CFR 201.55 - Statement of dosage.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 4 2014-04-01 2014-04-01 false Statement of dosage. 201.55 Section 201.55 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL LABELING Labeling Requirements for Prescription Drugs and/or Insulin § 201.55 Statement of...

  7. Calculating Dosages: A Programed Learner for Student Nurses.

    ERIC Educational Resources Information Center

    Hare, Mary

    Intended for nursing students, this programed workbook contains learning exercises and study tests on using household, apothecary, and metric systems in calculating medication dosages. The material, organized in six learning units, was designed to help students meet six objectives: correctly interpret and use accepted symbols and abbreviations in…

  8. Recent progress and open questions in Drosophila dosage compensation.

    PubMed

    Vensko, Steven P; Stone, Eric A

    2015-01-01

    Sexual dimorphism is observed in many traits across diverse taxa, and often it is quite extreme. Within a species, individuals of opposing sex can appear strikingly different, reflecting differences at the molecular level that may be similarly striking. Among the most extreme cases of such molecular sexual dimorphism is the quantity of sex chromosomes that each sex possesses. Hemizygous sex chromosomes are common to many species, and various mechanisms have evolved to regulate transcriptional activity to ensure appropriate sex chromosome-to-autosome gene expression stoichiometry. Among the most thoroughly investigated of these mechanisms is Drosophila melanogaster's male-specific lethal (MSL) complex-mediated dosage compensation. In Drosophila, the male X chromosome transcription is upregulated approximately two-fold in somatic tissues to counterbalance the effects of sex chromosome hemizygosity on transcript abundance. Despite dramatic advances in our understanding of the Drosophila dosage compensation, many questions remain unanswered, and our understanding of its molecular underpinnings remains incomplete. In this review, we synthesize recent progress in the field as a means to highlight open questions, including how the MSL complex targets the X chromosome, how dosage compensation has shaped evolution of X-linked genes, and the degree to which MSL complex-mediated dosage compensation varies in activity across somatic tissues. PMID:26213294

  9. 21 CFR 520.1448 - Monensin oral dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Monensin oral dosage forms. 520.1448 Section 520.1448 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... starting line). The loss on drying is not more than 10 percent when dried in vacuum at 60 °C for 2 hours....

  10. 21 CFR 520.1448 - Monensin oral dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Monensin oral dosage forms. 520.1448 Section 520.1448 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... starting line). The loss on drying is not more than 10 percent when dried in vacuum at 60 °C for 2 hours....

  11. 21 CFR 520.1448 - Monensin oral dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Monensin oral dosage forms. 520.1448 Section 520.1448 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... starting line). The loss on drying is not more than 10 percent when dried in vacuum at 60 °C for 2 hours....

  12. Health Instruction Packages: Drug Dosage, Classification, and Mixing.

    ERIC Educational Resources Information Center

    Bracchi, Dorothy P.; And Others

    Text, illustrations, and exercises are utilized in a set of seven learning modules to instruct nursing students in the fundamentals of drug classification, dosage, and mixing. The first module, by Dorothy Bracchi, teaches the student to identify six classifications of medication often administered to orthopedic patients: anti-neurospasmolytic…

  13. 76 FR 78815 - Oral Dosage Form New Animal Drugs; Cyclosporine

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-20

    ... HUMAN SERVICES Food and Drug Administration 21 CFR Part 520 Oral Dosage Form New Animal Drugs... Administration (FDA) is amending the animal drug regulations to reflect approval of a new animal drug application (NADA) filed by Novartis Animal Health US, Inc. The NADA provides for the veterinary prescription use...

  14. 75 FR 67031 - Oral Dosage Form New Animal Drugs; Domperidone

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-01

    ... HUMAN SERVICES Food and Drug Administration 21 CFR Part 520 Oral Dosage Form New Animal Drugs... Administration (FDA) is amending the animal drug regulations to reflect the original approval of a new animal.... 801-808. List of Subjects in 21 CFR Part 520 Animal drugs. 0 Therefore, under the Federal Food,...

  15. Software for Dosage Individualization of Voriconazole for Immunocompromised Patients

    PubMed Central

    VanGuilder, Michael; Donnelly, J. Peter; Blijlevens, Nicole M. A.; Brüggemann, Roger J. M.; Jelliffe, Roger W.; Neely, Michael N.

    2013-01-01

    The efficacy of voriconazole is potentially compromised by considerable pharmacokinetic variability. There are increasing insights into voriconazole concentrations that are safe and effective for treatment of invasive fungal infections. Therapeutic drug monitoring is increasingly advocated. Software to aid in the individualization of dosing would be an extremely useful clinical tool. We developed software to enable the individualization of voriconazole dosing to attain predefined serum concentration targets. The process of individualized voriconazole therapy was based on concepts of Bayesian stochastic adaptive control. Multiple-model dosage design with feedback control was used to calculate dosages that achieved desired concentration targets with maximum precision. The performance of the software program was assessed using the data from 10 recipients of an allogeneic hematopoietic stem cell transplant (HSCT) receiving intravenous (i.v.) voriconazole. The program was able to model the plasma concentrations with a high level of precision, despite the wide range of concentration trajectories and interindividual pharmacokinetic variability. The voriconazole concentrations predicted after the last dosages were largely concordant with those actually measured. Simulations provided an illustration of the way in which the software can be used to adjust dosages of patients falling outside desired concentration targets. This software appears to be an extremely useful tool to further optimize voriconazole therapy and aid in therapeutic drug monitoring. Further prospective studies are now required to define the utility of the controller in daily clinical practice. PMID:23380734

  16. Removal of Acid Orange 7 from aqueous solution using magnetic graphene/chitosan: a promising nano-adsorbent.

    PubMed

    Sheshmani, Shabnam; Ashori, Alireza; Hasanzadeh, Saeed

    2014-07-01

    Magnetic graphene/chitosan (MGCh) nanocomposite was fabricated through a facile chemical route and its application as a new adsorbent for Acid Orange 7 (AO7) removal was also investigated. After synthesis, the full characterization with various techniques (FTIR, XRD, VSM, and SEM) was achieved revealing many possible interactions/forces of dye-composite system. The results showed that, benefiting from the surface property of graphene oxide, the abundant amino and hydroxyl functional groups of chitosan, and from the magnetic property of Fe3O4, the adsorbent possesses quite a good and versatile adsorption capacity to the dye under investigation, and can be easily and rapidly extracted from water by magnetic attraction. The maximum absorption capacity was reached at initial pH 3 and 120min contact time. The batch adsorption experiments showed that the adsorption of the AO7 is considerably dependent on pH of milieu, amount of adsorbent, and contact time. The adsorption kinetics and isotherms were investigated to indicate that the kinetic and equilibrium adsorption were well-described by pseudo-first order kinetic and Langmuir isotherm model, respectively. The adsorption behavior suggested that the adsorbent surface was homogeneous in nature. The study suggests that the MGCh is a promising nano adsorbent for removal of anionic azo dyes from aqueous solution. PMID:24813679

  17. Evaluation of pharmaceuticals removal by sewage sludge-derived adsorbents with rapid small-scale column tests

    NASA Astrophysics Data System (ADS)

    Zhang, P.; Ding, R.; Wallace, R.; Bandosz, T.

    2015-12-01

    New composite adsorbents were developed by pyrolyzing sewage sludge and fish waste (75:25 or 90:10 dry mass ratio) at 650 oC and 950 oC. Batch adsorption experiments demonstrated that the composite adsorbents were able to adsorb a wide range of organic contaminants (volatile organic compounds, pharmaceuticals and endocrine disrupting compounds (EDCs), and nitrosamine disinfection byproducts) with high capacities. Here we further examine the performance of the adsorbents for the simultaneous removal of 8 pharmaceuticals and EDCs with rapid small-scale column tests (RSSCT). Results show that the order of breakthrough in RSSCT is in general consistent with the affinity determined via batch tests. As expected, the maximum amount of adsorption for each compound obtained from RSSCT is identical to or less than that obtained from batch tests (with only one exception), due to adsorption kinetics. However, despite the very different input concentration (1 mg/L vs. 100 mg/L) and contact time (2 min empty bed contact time vs. 16 hour equilibrium time) used in RSSCT and batch tests, the maximum amount of pharmaceuticals and EDCs adsorbed under RSSCT is still about one half of that under equilibrium batch tests, validating the approach of using batch tests with much higher input concentrations to determine adsorption capacities. Results of a pilot-scale column test in a drinking water treatment plant for pharmaceuticals removal will also be presented.

  18. Natural Transformation of Azotobacter vinelandii by Adsorbed Chromosomal DNA: Role of Adsorbed DNA Conformation

    NASA Astrophysics Data System (ADS)

    Lv, N.; Zilles, J.; Nguyen, H.

    2008-12-01

    Recent increases in antibiotic resistance among pathogenic microorganisms and the accompanying public health concerns result both from the widespread use of antibiotics and from the transfer of antibiotic resistance genes among microorganisms. To understand the transfer of antibiotic resistance genes and identify efficient measures to minimize these transfers, an interdisciplinary approach was used to identify physical and chemical factors that control the fate and biological availability of extracellular DNA. Quartz crystal microbalance with dissipation (QCM-D) was used to study extracellular DNA adsorption and the conformation of the adsorbed DNA on silica and natural organic matter (NOM) surfaces. Solution chemistry was varied systematically to investigate the role of adsorbed DNA conformation on transformation. Gene transfer was assessed under the same conditions using natural transformation of chromosomal DNA into the soil bacteria Azotobacter vinelandii. DNA adsorbed to both silica and NOM surfaces has a more compact and rigid conformation in the presence of Ca2+ compared to Na+. Extracellular DNA adsorbed on silica and NOM surfaces transformed A. vinelandii. The transformation efficiency of adsorbed DNA was up to 4 orders of magnitude lower than that of dissolved DNA. Preliminary results suggest that the presence of Ca2+ in groundwater (e.g. hardness) reduces the availability of adsorbed DNA for transformation.

  19. EMERGING TECHNOLOGY SUMMARY: DEMONSTRATION OF AMBERSORB 563 ADSORBENT TECHNOLOGY

    EPA Science Inventory

    A field pilot study was conducted to demonstrate the technical feasibility and cost-effectiveness of Ambersorb® 5631 carbonaceous adsorbent for remediating groundwater contaminated with volatile organic compounds (VOCs). The Ambersorb adsorbent technology demonstration consist...

  20. Modeling Effective Dosages in Hormetic Dose-Response Studies

    PubMed Central

    Belz, Regina G.; Piepho, Hans-Peter

    2012-01-01

    Background Two hormetic modifications of a monotonically decreasing log-logistic dose-response function are most often used to model stimulatory effects of low dosages of a toxicant in plant biology. As just one of these empirical models is yet properly parameterized to allow inference about quantities of interest, this study contributes the parameterized functions for the second hormetic model and compares the estimates of effective dosages between both models based on 23 hormetic data sets. Based on this, the impact on effective dosage estimations was evaluated, especially in case of a substantially inferior fit by one of the two models. Methodology/Principal Findings The data sets evaluated described the hormetic responses of four different test plant species exposed to 15 different chemical stressors in two different experimental dose-response test designs. Out of the 23 data sets, one could not be described by any of the two models, 14 could be better described by one of the two models, and eight could be equally described by both models. In cases of misspecification by any of the two models, the differences between effective dosages estimates (0–1768%) greatly exceeded the differences observed when both models provided a satisfactory fit (0–26%). This suggests that the conclusions drawn depending on the model used may diverge considerably when using an improper hormetic model especially regarding effective dosages quantifying hormesis. Conclusions/Significance The study showed that hormetic dose responses can take on many shapes and that this diversity can not be captured by a single model without risking considerable misinterpretation. However, the two empirical models considered in this paper together provide a powerful means to model, prove, and now also to quantify a wide range of hormetic responses by reparameterization. Despite this, they should not be applied uncritically, but after statistical and graphical assessment of their adequacy. PMID

  1. Analysis of Adsorbed Natural Gas Tank Technology

    NASA Astrophysics Data System (ADS)

    Knight, Ernest; Schultz, Conrad; Rash, Tyler; Dohnke, Elmar; Stalla, David; Gillespie, Andrew; Sweany, Mark; Seydel, Florian; Pfeifer, Peter

    With gasoline being an ever decreasing finite resource and with the desire to reduce humanity's carbon footprint, there has been an increasing focus on innovation of alternative fuel sources. Natural gas burns cleaner, is more abundant, and conforms to modern engines. However, storing compressed natural gas (CNG) requires large, heavy gas cylinders, which limits space and fuel efficiency. Adsorbed natural gas (ANG) technology allows for much greater fuel storage capacity and the ability to store the gas at a much lower pressure. Thus, ANG tanks are much more flexible in terms of their size, shape, and weight. Our ANG tank employs monolithic nanoporous activated carbon as its adsorbent material. Several different configurations of this Flat Panel Tank Assembly (FPTA) along with a Fuel Extraction System (FES) were examined to compare with the mass flow rate demands of an engine.

  2. Gas storage using fullerene based adsorbents

    NASA Technical Reports Server (NTRS)

    Loutfy, Raouf O. (Inventor); Lu, Xiao-Chun (Inventor); Li, Weijiong (Inventor); Mikhael, Michael G. (Inventor)

    2000-01-01

    This invention is directed to the synthesis of high bulk density high gas absorption capacity adsorbents for gas storage applications. Specifically, this invention is concerned with novel gas absorbents with high gravimetric and volumetric gas adsorption capacities which are made from fullerene-based materials. By pressing fullerene powder into pellet form using a conventional press, then polymerizing it by subjecting the fullerene to high temperature and high inert gas pressure, the resulting fullerene-based materials have high bulk densities and high gas adsorption capacities. By pre-chemical modification or post-polymerization activation processes, the gas adsorption capacities of the fullerene-based adsorbents can be further enhanced. These materials are suitable for low pressure gas storage applications, such as oxygen storage for home oxygen therapy uses or on-board vehicle natural gas storage. They are also suitable for storing gases and vapors such as hydrogen, nitrogen, carbon dioxide, and water vapor.

  3. Computer simulations of adsorbed liquid crystal films

    NASA Astrophysics Data System (ADS)

    Wall, Greg D.; Cleaver, Douglas J.

    2003-01-01

    The structures adopted by adsorbed thin films of Gay-Berne particles in the presence of a coexisting vapour phase are investigated by molecular dynamics simulation. The films are adsorbed at a flat substrate which favours planar anchoring, whereas the nematic-vapour interface favours normal alignment. On cooling, a system with a high molecule-substrate interaction strength exhibits substrate-induced planar orientational ordering and considerable stratification is observed in the density profiles. In contrast, a system with weak molecule-substrate coupling adopts a director orientation orthogonal to the substrate plane, owing to the increased influence of the nematic-vapour interface. There are significant differences between the structures adopted at the two interfaces, in contrast with the predictions of density functional treatments of such systems.

  4. Static and dynamic properties of tethered chains at adsorbing surfaces: A Monte Carlo study

    NASA Astrophysics Data System (ADS)

    Descas, Radu; Sommer, Jens-Uwe; Blumen, Alexander

    2004-05-01

    We present extensive Monte Carlo simulations of tethered chains of length N on adsorbing surfaces, considering the dilute case in good solvents, and analyze our results using scaling arguments. We focus on the mean number M of chain contacts with the adsorbing wall, on the chain's extension (the radius of gyration) perpendicular and parallel to the adsorbing surface, on the probability distribution of the free end and on the density profile for all monomers. At the critical adsorption strength ɛc one has Mc˜Nφ, and we find (using the above results) as best candidate φ to equal 0.59. However, slight changes in the estimation of ɛc lead to large deviations in the resulting φ; this might be a possible reason for the difference in the φ values reported in the literature. We also investigate the dynamical scaling behavior at ɛc, by focusing on the end-to-end correlation function and on the correlation function of monomers adsorbed at the wall. We find that at ɛc the dynamic scaling exponent a (which describes the relaxation time of the chain as a function of N) is the same as that of free chains. Furthermore, we find that for tethered chains the modes perpendicular to the surface relax quicker than those parallel to it, which may be seen as a splitting in the relaxation spectrum.

  5. Swelling induced regeneration of TiO2-impregnated chitosan adsorbents under visible light.

    PubMed

    Yang, Limin; Jiang, Lei; Hu, Di; Yan, Qingyun; Wang, Zhi; Li, Sisi; Chen, Cheng; Xue, Qi

    2016-04-20

    Since only the molecules that are in direct contact with the TiO2 surface undergo photosensitization, it is challenging to regenerate the TiO2-impregnated chitosan (TIC) adsorbent beads under visible light. This study focused on the role of chitosan swelling properties. It was found that dye-loaded TIC adsorbent exhibited a pH-dependent swelling owing to protonation/deprotonation of free amino groups on chitosan chains. In the acidic medium (pH<6.0), the adsorbent underwent a 'smart' phase transition from a dry contracted state to a hydrated swollen state, and its physicochemical properties were also significantly changed, which eventually enabled the photosensitized oxidation of dye. This swelling induced regeneration was further confirmed by Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The involvement of oxygen radical species (O2(-)/HOO and OH) was also confirmed with electron spin resonance (ESR) spectroscopy. Moreover, the adsorption effectiveness of TIC adsorbent was mostly recovered after six regeneration cycles. PMID:26876871

  6. Adsorption of Procion Red MX 8B using spent tea leaves as adsorbent

    NASA Astrophysics Data System (ADS)

    Heraldy, Eddy; Osa, Riesta Ramdhaniyati; Suryanti, Venty

    2016-02-01

    The adsorption of Procion Red MX 8B using spent tea leaves (STL) as adsorbent, has been studied by batch adsorption technique. The adsorbent was activated by NaOH 4% for 24 hours for delignification process. The adsorbent was characterized using FTIR to indetify the functional groups of cellulose was shown by uptake -OH, C-H and C-O. The optimum conditions of adsorption experiments were achieved when pH was set as 6 with contact time of 75 minutes and capacity of adsorption was 3.28 mg/g. The equilibrium data were fitted to Langmuir and Isotherm Freundlichs. The kinetic models, pseudo first order and pseudo second order were employed to describe the adsorption mechanism. The experimental results showed that the pseudo second order equation was the best model that described the adsorption behavior with the coefficient of correlation (R2) was equal higher than 0.99 The results suggested that STL had high potential to be used as effective adsorbent for Procion Red MX 8B removal.

  7. Tailoring fly ash activated with bentonite as adsorbent for complex wastewater treatment

    NASA Astrophysics Data System (ADS)

    Visa, Maria

    2012-12-01

    Used as adsorbent, alkali fly ash represents a low cost solution for advanced wastewater treatment. The alkali treatment raises sustainability issues therefore, in this research we aim to replace alkali fly ash with washed fly ash (FAw). For improving the adsorption capacity of washed fly ash, bentonite powder (B) was added, as a natural adsorbent with a composition almost identical to the fly ash. The new adsorbent was characterized by AFM, XRD, FTIR, SEM, EDS and the surface energy was evaluated by contact angle measurements. For understanding the complex adsorption process on this mixed substrate, preliminary tests were developed on synthetic wastewaters containing a single pollutant system (heavy metal), binary (two-heavy metals) and ternary (dye and two heavy metals) systems. Experiments were done on synthetic wastewaters containing methylene blue, cadmium and copper, using FAw, B and their powder mixtures. The pseudo-second order kinetics could well model all the processes, indicating a good adsorbent material which can be used for the pollutants removal from wastewater. After adsorption the substrates loaded with pollutants, annealed at 500 °C can be reused for padding in stone blocks.

  8. Many-body dispersion effects in the binding of adsorbates on metal surfaces

    SciTech Connect

    Maurer, Reinhard J.; Ruiz, Victor G.; Tkatchenko, Alexandre

    2015-09-14

    A correct description of electronic exchange and correlation effects for molecules in contact with extended (metal) surfaces is a challenging task for first-principles modeling. In this work, we demonstrate the importance of collective van der Waals dispersion effects beyond the pairwise approximation for organic–inorganic systems on the example of atoms, molecules, and nanostructures adsorbed on metals. We use the recently developed many-body dispersion (MBD) approach in the context of density-functional theory [Tkatchenko et al., Phys. Rev. Lett. 108, 236402 (2012) and Ambrosetti et al., J. Chem. Phys. 140, 18A508 (2014)] and assess its ability to correctly describe the binding of adsorbates on metal surfaces. We briefly review the MBD method and highlight its similarities to quantum-chemical approaches to electron correlation in a quasiparticle picture. In particular, we study the binding properties of xenon, 3,4,9,10-perylene-tetracarboxylic acid, and a graphene sheet adsorbed on the Ag(111) surface. Accounting for MBD effects, we are able to describe changes in the anisotropic polarizability tensor, improve the description of adsorbate vibrations, and correctly capture the adsorbate–surface interaction screening. Comparison to other methods and experiment reveals that inclusion of MBD effects improves adsorption energies and geometries, by reducing the overbinding typically found in pairwise additive dispersion-correction approaches.

  9. Fluoride removal from aqueous solution by Al(III)-Zr(IV) binary oxide adsorbent

    NASA Astrophysics Data System (ADS)

    Zhu, Jiuya; Lin, Xiaoyan; Wu, Pengwei; Zhou, Qiusheng; Luo, Xuegang

    2015-12-01

    In this study, a novel binary oxide adsorbent of Al2O3-ZrO2 was prepared via coprecipitation followed by calcination method, and the calcination temperatures were investigated. The adsorbent was characterized by XRD, EDX and XPS. The batch adsorption experiments were carried out at different parameters, such as solution pH, adsorbent dose, contact time, initial fluoride concentration and adsorption temperature, to evaluate the fluoride removal performance. The results showed that the adsorption isotherm was better described by the linear Langmuir model, and a maximum adsorption capacity was 114.54 mg/g. The adsorption kinetics was well fitted by the linear pseudo-second-order, and the correlation coefficient value (R2) was 0.997. The thermodynamic parameters of ΔH0, ΔS0 and ΔG0 were calculated, which showed that the fluoride adsorption process was spontaneous and exothermic. And the possible adsorption mechanism of the adsorbent for fluoride could involve the ligand-exchange and ion-exchange based on the results in the study.

  10. Simulations of noble gases adsorbed on graphene

    NASA Astrophysics Data System (ADS)

    Maiga, Sidi; Gatica, Silvina

    2014-03-01

    We present results of Grand Canonical Monte Carlo simulations of adsorption of Kr, Ar and Xe on a suspended graphene sheet. We compute the adsorbate-adsorbate interaction by a Lennard-Jones potential. We adopt a hybrid model for the graphene-adsorbate force; in the hybrid model, the potential interaction with the nearest carbon atoms (within a distance rnn) is computed with an atomistic pair potential Ua; for the atoms at r>rnn, we compute the interaction energy as a continuous integration over a carbon uniform sheet with the density of graphene. For the atomistic potential Ua, we assume the anisotropic LJ potential adapted from the graphite-He interaction proposed by Cole et.al. This interaction includes the anisotropy of the C atoms on graphene, which originates in the anisotropic π-bonds. The adsorption isotherms, energy and structure of the layer are obtained and compared with experimental results. We also compare with the adsorption on graphite and carbon nanotubes. This research was supported by NSF/PRDM (Howard University) and NSF (DMR 1006010).

  11. Orbital tomography for highly symmetric adsorbate systems

    NASA Astrophysics Data System (ADS)

    Stadtmüller, B.; Willenbockel, M.; Reinisch, E. M.; Ules, T.; Bocquet, F. C.; Soubatch, S.; Puschnig, P.; Koller, G.; Ramsey, M. G.; Tautz, F. S.; Kumpf, C.

    2012-10-01

    Orbital tomography is a new and very powerful tool to analyze the angular distribution of a photoemission spectroscopy experiment. It was successfully used for organic adsorbate systems to identify (and consequently deconvolute) the contributions of specific molecular orbitals to the photoemission data. The technique was so far limited to surfaces with low symmetry like fcc(110) oriented surfaces, owing to the small number of rotational domains that occur on such surfaces. In this letter we overcome this limitation and present an orbital tomography study of a 3,4,9,10-perylene-tetra-carboxylic-dianhydride (PTCDA) monolayer film adsorbed on Ag(111). Although this system exhibits twelve differently oriented molecules, the angular resolved photoemission data still allow a meaningful analysis of the different local density of states and reveal different electronic structures for symmetrically inequivalent molecules. We also discuss the precision of the orbital tomography technique in terms of counting statistics and linear regression fitting algorithm. Our results demonstrate that orbital tomography is not limited to low-symmetry surfaces, a finding which makes a broad field of complex adsorbate systems accessible to this powerful technique.

  12. Colored Contact Lens Dangers

    MedlinePlus

    ... Halloween Hazard: The Hidden Dangers of Buying Decorative Contact Lenses Without a Prescription Sep. 26, 2013 It ... she first put in a pair of colored contact lenses, Laura Butler of Parkersburg, W.Va., had " ...

  13. Allergic Contact Dermatitis

    MedlinePlus

    ... causes of allergic contact dermatitis include nickel, chromates, rubber chemicals, and topical antibiotic ointments and creams. Frequent ... construction workers who are in contact with cement. Rubber chemicals are found in gloves, balloons, elastic in ...

  14. PREFACE: Non-contact AFM Non-contact AFM

    NASA Astrophysics Data System (ADS)

    Giessibl, Franz J.; Morita, Seizo

    2012-02-01

    This special issue is focussed on high resolution non-contact atomic force microscopy (AFM). Non-contact atomic force microscopy was established approximately 15 years ago as a tool to image conducting and insulating surfaces with atomic resolution. Since 1998, an annual international conference has taken place, and although the proceedings of these conferences are a useful source of information, several key developments warrant devoting a special issue to this subject. In the theoretic field, the possibility of supplementing established techniques such as scanning tunneling microscopy (STM) and Kelvin probe microscopy with atomically resolved force micrsoscopy poses many challenges in the calculation of contrast and contrast reversal. The surface science of insulators, self-assembled monolayers and adsorbates on insulators is a fruitful field for the application of non-contact AFM: several articles in this issue are devoted to these subjects. Atomic imaging and manipulation have been pioneered using STM, but because AFM allows the measurement of forces, AFM has had a profound impact in this field as well. Three-dimensional force spectroscopy has allowed many important insights into surface science. In this issue a combined 3D tunneling and force microscopy is introduced. Non-contact AFM typically uses frequency modulation to measure force gradients and was initially used mainly in a vacuum. As can be seen in this issue, frequency modulation is now also used in ambient conditions, allowing better spatial and force resolution. We thank all of the contributors for their time and efforts in making this special issue possible. We are also very grateful to the staff of IOP Publishing for handling the administrative aspects and for steering the refereeing process. Non-contact AFM contents Relation between the chemical force and the tunnelling current in atomic point contacts: a simple model Pavel Jelínek, Martin Ondrácek and Fernando Flores Theoretical simulation of

  15. Glasses and Contact Lenses

    MedlinePlus

    ... Here's Help White House Lunch Recipes Glasses and Contact Lenses KidsHealth > For Kids > Glasses and Contact Lenses Print A A A Text Size What's ... together the way they should. But eyeglasses or contact lenses, also called corrective lenses, can help most ...

  16. Evaluation of raw soapstone (steatite) as adsorbent of trace elements present in Brazilian spirits.

    PubMed

    Louvera Silva, Karine Aparecida; da Costa Fernandes, Isabela; Bearzoti, Eduardo; Milani, Raquel Fernanda; Morgano, Marcelo Antonio; Quintaes, Kesia Diego

    2016-06-01

    The impact of soapstone (steatite) upon inorganic element contaminant concentrations in alcoholic beverages was investigated. Concentrations of As, Cd, Cu, Ni and Pb levels in 8 Brazilian spirits plus an alcoholic simulant were initially measured, and then measured following each 24h cycle of exposure to raw soapstone cups, for a total of 4 cycles/sample. The results were compared to the levels established by Brazilian and German regulations. The contact between the spirits and the soapstone reduced the Cu content by up to 50.4% and increased the Ni content by up to 622.2%, especially in the first contact cycle. The exposure of spirits to the soapstone exhibits a linear reduction in the Pb content (18.3-54.5%) while As and Cd levels remained unaltered throughout the experiments. In conclusion, crude soapstone in contact with alcoholic solutions acts as an adsorbent of trace elements (Cu and Pb) while releasing Ni. PMID:26830564

  17. Contact lens in keratoconus

    PubMed Central

    Rathi, Varsha M; Mandathara, Preeji S; Dumpati, Srikanth

    2013-01-01

    Contact lenses are required for the visual improvement in patients with keratoconus. Various contact lens options, such as rigid gas permeable (RGP) lenses, soft and soft toric lenses, piggy back contact lenses (PBCL), hybrid lenses and scleral lenses are availble. This article discusses about selection of a lens depending on the type of keratoconus and the fitting philosophies of various contact lenses including the starting trial lens. A Medline search was carried out for articles in the English language with the keywords keratoconus and various contact lenses such as Rose k lens, RGP lens, hybrid lens, scleral lens and PBCL. PMID:23925325

  18. Dosage compensation of the sex chromosomes and autosomes.

    PubMed

    Disteche, Christine M

    2016-08-01

    Males are XY and females are XX in most mammalian species. Other species such as birds have a different sex chromosome make-up: ZZ in males and ZW in females. In both types of organisms one of the sex chromosomes, Y or W, has degenerated due to lack of recombination with its respective homolog X or Z. Since autosomes are present in two copies in diploid organisms the heterogametic sex has become a natural "aneuploid" with haploinsufficiency for X- or Z-linked genes. Specific mechanisms have evolved to restore a balance between critical gene products throughout the genome and between males and females. Some of these mechanisms were co-opted from and/or added to compensatory processes that alleviate autosomal aneuploidy. Surprisingly, several modes of dosage compensation have evolved. In this review we will consider the evidence for dosage compensation and the molecular mechanisms implicated. PMID:27112542

  19. RFID Tag Helix Antenna Sensors for Wireless Drug Dosage Monitoring.

    PubMed

    Huang, Haiyu; Zhao, Peisen; Chen, Pai-Yen; Ren, Yong; Liu, Xuewu; Ferrari, Mauro; Hu, Ye; Akinwande, Deji

    2014-01-01

    Miniaturized helix antennas are integrated with drug reservoirs to function as RFID wireless tag sensors for real-time drug dosage monitoring. The general design procedure of this type of biomedical antenna sensors is proposed based on electromagnetic theory and finite element simulation. A cost effective fabrication process is utilized to encapsulate the antenna sensor within a biocompatible package layer using PDMS material, and at the same time form a drug storage or drug delivery unit inside the sensor. The in vitro experiment on two prototypes of antenna sensor-drug reservoir assembly have shown the ability to monitor the drug dosage by tracking antenna resonant frequency shift from 2.4-2.5-GHz ISM band with realized sensitivity of 1.27 [Formula: see text] for transdermal drug delivery monitoring and 2.76-[Formula: see text] sensitivity for implanted drug delivery monitoring. PMID:27170865

  20. Effect of different curcumin dosages on human gall bladder.

    PubMed

    Rasyid, Abdul; Rahman, Abdul Rashid Abdul; Jaalam, Kamaruddin; Lelo, Aznan

    2002-01-01

    Our previous study demonstrated that curcumin, an active compound of Curcuma xanthorrhiza and C. domestica, produces a positive cholekinetic effect. A 20 mg amount of curcumin is capable of contracting the gall bladder by up to 29% within an observation time of 2 h. The aim of the current study was to define the dosage of curcumin capable of producing a 50% contraction of the gall bladder, and to determine if there is a linear relationship between doubling the curcumin dosage and the doubling of gall bladder contraction. A randomised, single-blind, three-phase, crossover-designed examination was carried out on 12 healthy volunteers. Ultrasonography was carried out serially to measure the gall bladder volume. The data obtained was analysed by analysis of variance (ANOVA). The fasting volumes of gall bladders were similar (P > 0.50), with 17.28 +/- 5.47 mL for 20 mg curcumin, 18.34 +/- 3.75 mL for 40 mg and 18.24 +/- 3.72 mL for 80 mg. The percentage decrease in gall bladder volume 2 h after administration of 20, 40 and 80 mg was 34.10 +/- 10.16, 51.15 +/- 8.08 and 72.25 +/- 8.22, respectively, which was significantly different (P < 0.01). On the basis of the present findings, it appears that the dosage of cucumin capable of producing a 50% contraction of the bladder was 40 mg. This study did not show any linear relationship between doubling curcumin dosage and the doubling of gall bladder contraction. PMID:12495265

  1. Dipolar capillary interactions between tilted ellipsoidal particles adsorbed at fluid-fluid interfaces.

    PubMed

    Davies, Gary B; Botto, Lorenzo

    2015-10-28

    Capillary interactions have emerged as a tool for the directed assembly of particles adsorbed at fluid-fluid interfaces, and play a role in controlling the mechanical properties of emulsions and foams. In this paper, following Davies et al. [Adv. Mater., 2014, 26, 6715] investigation into the assembly of ellipsoidal particles at interfaces interacting via dipolar capillary interactions, we numerically investigate the interaction between tilted ellipsoidal particles adsorbed at a fluid-fluid interface as their aspect ratio, tilt angle, bond angle, and separation vary. High-resolution Surface Evolver simulations of ellipsoidal particle pairs in contact reveal an energy barrier between a metastable tip-tip configuration and a stable side-side configuration. The side-side configuration is the global energy minimum for all parameters we investigated. Lattice Boltzmann simulations of clusters of up to 12 ellipsoidal particles show novel highly symmetric flower-like and ring-like arrangements. PMID:26323324

  2. Magnetic nanopowder as effective adsorbent for the removal of Congo Red from aqueous solution.

    PubMed

    Paşka, O; Ianoş, R; Păcurariu, C; Brădeanu, A

    2014-01-01

    A magnetic iron oxide nanopowder (MnP), prepared by a simple and efficient combustion synthesis technique, was tested for the removal of the anionic dye Congo Red (CR) from aqueous solution. The influence of solution pH, adsorbent dose, temperature, contact time and initial dye concentration on the adsorption of CR onto MnP were investigated. It was shown that the CR adsorption was pH dependent and the adsorption mechanism was governed by electrostatic forces. The adsorption kinetic was best described by the pseudo-second-order model and the equilibrium data were well fitted to the Langmuir isotherm, yielding maximum adsorption capacity of 54.46 mg g(-1). The undeniable advantages of the MnP adsorbent such as inexpensive preparation method, good adsorption capacity and easy separation using an external magnetic field, recommend it as a promising candidate for the removal of anionic dyes from polluted water. PMID:24647189

  3. Status of dosage compensation of X chromosome in bovine genome.

    PubMed

    Ka, Sojeong; Ahn, Hyeonju; Seo, Minseok; Kim, Heebal; Kim, Jin Nam; Lee, Hyun-Jeong

    2016-08-01

    Dosage compensation system with X chromosome upregulation and inactivation have evolved to overcome the genetic imbalance between sex chromosomes in both male and female of mammals. Although recent development of chromosome-wide technologies has allowed us to test X upregulation, discrete data processing and analysis methods draw disparate conclusions. A series of expression studies revealed status of dosage compensation in some species belonging to monotremes, marsupials, rodents and primates. However, X upregulation in the Artiodactyla order including cattle have not been studied yet. In this study, we surveyed the genome-wide transcriptional upregulation in X chromosome in cattle RNA-seq data using different gene filtration methods. Overall examination of RNA-seq data revealed that X chromosome in the pituitary gland expressed more genes than in other peripheral tissues, which was consistent with the previous results observed in human and mouse. When analyzed with globally expressed genes, a median X:A expression ratio was 0.94. The ratio of 1-to-1 ortholog genes between chicken and mammals, however, showed considerable reduction to 0.68. These results indicate that status of dosage compensation for cattle is not deviated from those found in rodents and primate, and this is consistent with the evolutionary history of cattle. PMID:27376899

  4. Biowaiver Monographs for Immediate Release Solid Oral Dosage Forms: Levetiracetam.

    PubMed

    Petruševska, Marija; Berglez, Sandra; Krisch, Igor; Legen, Igor; Megušar, Klara; Peternel, Luka; Abrahamsson, Bertil; Cristofoletti, Rodrigo; Groot, D W; Kopp, Sabine; Langguth, Peter; Mehta, Mehul; Polli, James E; Shah, Vinod P; Dressman, Jennifer

    2015-09-01

    Literature and experimental data relevant for the decision to allow a waiver of in vivo bioequivalence (BE) testing for the approval of immediate release (IR) solid oral dosage forms containing levetiracetam are reviewed. Data on solubility and permeability suggest that levetiracetam belongs to class I of the biopharmaceutical classification system (BCS). Levetiracetam's therapeutic use, its wide therapeutic index, and its favorable pharmacokinetic properties make levetiracetam a valid candidate for the BCS-based biowaiver approach. Further, no BE studies with levetiracetam IR formulations in which the test formulation failed to show BE with the comparator have been reported in the open literature. On the basis of the overall evidence, it appears unlikely that a BCS-based biowaiver approach for levetiracetam IR solid oral dosage forms formulated with established excipients would expose patients to undue risks. Thus, the BCS-based biowaiver approach procedure is recommended for IR solid oral dosage form containing levetiracetam, provided the excipients in the formulation are also present in products that have been approved in countries belonging to or associated with the International Committee on Harmonization and are used in their usual quantities, and provided the dissolution profiles of the test and reference product comply with the current requirements for BCS-based biowaivers. PMID:25663270

  5. Spectrophotometric Assay of Mebendazole in Dosage Forms Using Sodium Hypochlorite

    NASA Astrophysics Data System (ADS)

    Swamy, N.; Prashanth, K. N.; Basavaiah, K.

    2014-07-01

    A simple, selective and sensitive spectrophotometric method is described for the determination of mebendazole (MBD) in bulk drug and dosage forms. The method is based on the reaction of MBD with hypochlorite in the presence of sodium bicarbonate to form the chloro derivative of MBD, followed by the destruction of the excess hypochlorite by nitrite ion. The color was formed by the oxidation of iodide with the chloro derivative of MBD to iodine in the presence of starch and forming the blue colored product, which was measured at 570 nm. The optimum conditions that affect the reaction were ascertained and, under these conditions, a linear relationship was obtained in the concentration range of 1.25-25.0·g/ml MBD. The calculated molar absorptivity and Sandell sensitivity values are 9.56·103 l·mol-1·cm-1 and 0.031 μg/cm2, respectively. The limits of detection and quantification are 0.11 and 0.33 μg/ml, respectively. The proposed method was applied successfully to the determination of MBD in bulk drug and dosage forms, and no interference was observed from excipients present in the dosage forms. The reliability of the proposed method was further checked by parallel determination by the reference method and also by recovery studies.

  6. Dosage Compensation in the African Malaria Mosquito Anopheles gambiae

    PubMed Central

    Rose, Graham; Krzywinska, Elzbieta; Kim, Jan; Revuelta, Loic; Ferretti, Luca; Krzywinski, Jaroslaw

    2016-01-01

    Dosage compensation is the fundamental process by which gene expression from the male monosomic X chromosome and from the diploid set of autosomes is equalized. Various molecular mechanisms have evolved in different organisms to achieve this task. In Drosophila, genes on the male X chromosome are upregulated to the levels of expression from the two X chromosomes in females. To test whether a similar mechanism is operating in immature stages of Anopheles mosquitoes, we analyzed global gene expression in the Anopheles gambiae fourth instar larvae and pupae using high-coverage RNA-seq data. In pupae of both sexes, the median expression ratios of X-linked to autosomal genes (X:A) were close to 1.0, and within the ranges of expression ratios between the autosomal pairs, consistent with complete compensation. Gene-by-gene comparisons of expression in males and females revealed mild female bias, likely attributable to a deficit of male-biased X-linked genes. In larvae, male to female ratios of the X chromosome expression levels were more female biased than in pupae, suggesting that compensation may not be complete. No compensation mechanism appears to operate in male germline of early pupae. Confirmation of the existence of dosage compensation in A. gambiae lays the foundation for research into the components of dosage compensation machinery in this important vector species. PMID:26782933

  7. Validation of a simplified netilmicin dosage regimen in infants.

    PubMed

    Klingenberg, Claus; Småbrekke, Lars; Lier, Tore; Flaegstad, Trond

    2004-01-01

    The aim of this study was to validate a simplified high-dosage, extended-interval netilmicin dosage regimen for infants. A total of 129 infants receiving 163 treatment courses of netilmicin (6 mg kg every 24 or 36 h depending on gestational age (GA), postnatal age and postmenstrual age) was analysed. Serum netilmicin concentrations were monitored before (Cmin), 30 min (C0.5h) after and 7.5 h (C7.5h) after the third dose. In 110 patients during first week of life mean C0.5h was 10.5 mg/l. Mean C0.5h was significantly lower (9.0 mg/l) in 38 infants older than 1 week of age. 14 of 15 patients with Cmin levels > or = 2 mg/l receiving netilmicin every 36 h were < 28 weeks of gestation. In the first week of life significant correlations between GA and elimination half-life (p < 0.001) and between plasma creatinine and elevated Cmin (p < 0.002) were found, but no correlation between C0.5h and GA. In this high-dosage regimen a dosing interval of 48 h for GA < 29 weeks, 36 h for GA 29-36 weeks and 24 h for full term babies seems appropriate, during first week of life, to avoid the majority of elevated trough levels and still obtain maximal therapeutic efficacy. PMID:15307571

  8. Modeling Thermal Contact Resistance

    NASA Technical Reports Server (NTRS)

    Kittel, Peter; Sperans, Joel (Technical Monitor)

    1994-01-01

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

  9. Magnesium oxide-impregnated tuff soil-derived ceramic: a novel cadmium(II) adsorbing media

    NASA Astrophysics Data System (ADS)

    Salim, Md; Bhakta, Jatindra N.; Maneesh, Namburath; Munekage, Yukihiro; Motomura, Kevin

    2015-07-01

    The contamination of cadmium (Cd) in the aquatic environment is one of the serious environmental and human health's risks. The present study attempted to develop the potential magnesium oxide (MgO)-impregnated tuff soil-derived ceramic (MITDC)-based novel adsorbent media for adsorbing higher rate of cadmium [Cd(II)] from water phase. A potential MITDC adsorbent media was developed using volcanic raw tuff soil and its Cd(II) adsorption capacity from water phase was evaluated comparing with the raw tuff soil. A series of studies were carried out in an agitated batch method at 20 ± 2 °C to characterize the adsorption capacity of MITDC under different conditions of factors, such as contact time (0-360 min), initial pH (3-11) of solution, dose of MITDC (2, 5, 7.5 and 10 g/L), and initial concentration of Cd(II) (5, 10, 20, 30, and 40 mg/L), influencing the adsorption mechanism. MITDC exhibited the equilibrium state of maximum Cd(II) adsorption at the contact time 120 min and pH 4.7 (removed 98.2 % Cd) when initial Cd(II) concentration was 10 mg/L in the present study. The dose of 7.5 g MITDC/L showed maximum removal of Cd(II) from water. Experimental data were described by the Freundlich and the Langmuir isotherms and equilibrium data fitted well with the Langmuir model (R 2 = 0.996). The Cd(II) adsorption capacity of MITDC was 31.25 mg/g. The high Cd(II) adsorption capacity indicated that novel MITDC could be used as a potential ceramic adsorbent media to remove high rate of Cd(II) from aqueous phase.

  10. Novel Adsorbent-Reactants for Treatment of Ash and Scrubber Pond Effluents

    SciTech Connect

    Bill Batchelor; Dong Suk Han; Eun Jung Kim

    2010-01-31

    The overall goal of this project was to evaluate the ability of novel adsorbent/reactants to remove specific toxic target chemicals from ash and scrubber pond effluents while producing stable residuals for ultimate disposal. The target chemicals studied were arsenic (As(III) and As(V)), mercury (Hg(II)) and selenium (Se(IV) and Se(VI)). The adsorbent/reactants that were evaluated are iron sulfide (FeS) and pyrite (FeS{sub 2}). Procedures for measuring concentrations of target compounds and characterizing the surfaces of adsorbent-reactants were developed. Effects of contact time, pH (7, 8, 9, 10) and sulfate concentration (0, 1, 10 mM) on removal of all target compounds on both adsorbent-reactants were determined. Stability tests were conducted to evaluate the extent to which target compounds were released from the adsorbent-reactants when pH changed. Surface characterization was conducted with x-ray photoelectron spectroscopy (XPS) to identify reactions occurring on the surface between the target compounds and surface iron and sulfur. Results indicated that target compounds could be removed by FeS{sub 2} and FeS and that removal was affected by time, pH and surface reactions. Stability of residuals was generally good and appeared to be affected by the extent of surface reactions. Synthesized pyrite and mackinawite appear to have the required characteristics for removing the target compounds from wastewaters from ash ponds and scrubber ponds and producing stable residuals.

  11. Removal of uranium from aqueous solution by a low cost and high-efficient adsorbent

    NASA Astrophysics Data System (ADS)

    Liu, Yun-Hai; Wang, You-Qun; Zhang, Zhi-Bin; Cao, Xiao-Hong; Nie, Wen-Bin; Li, Qin; Hua, Rong

    2013-05-01

    In this study, a low-cost and high-efficient carbonaceous adsorbent (HTC-COOH) with carboxylic groups was developed for U(VI) removal from aqueous solution compared with the pristine hydrothermal carbon (HTC). The structure and chemical properties of resultant adsorbents were characterized by Scanning electron microscope (SEM), N2 adsorption-desorption, Fourier transform-infrared spectra (FT-IR) and acid-base titration. The key factors (solution pH, contact time, initial U(VI) concentrations and temperature) affected the adsorption of U(VI) on adsorbents were investigated using batch experiments. The adsorption of U(VI) on HTC and HTC-COOH was pH-dependent, and increased with temperature and initial ion concentration. The adsorption equilibrium of U(VI) on adsorbents was well defined by the Langmuir isothermal equation, and the monolayer adsorption capacity of HTC-COOH was found to be 205.8 mg/g. The kinetics of adsorption was very in accordance with the pseudo-second-order rate model. The adsorption processes of U(VI) on HTC and HTC-COOH were endothermic and spontaneous in nature according to the thermodynamics of adsorption. Furthermore, HTC-COOH could selectively adsorption of U(VI) in aqueous solution containing co-existing ions (Mg2+, Co2+, Ni2+, Zn2+ and Mn2+). From the results of the experiments, it is found that the HTC-COOH is a potential adsorbent for effective removal of U(VI) from polluted water.

  12. Tuning the Receding Contact Angle on Hydrogels by Addition of Particles.

    PubMed

    Boulogne, François; Ingremeau, François; Limat, Laurent; Stone, Howard A

    2016-06-01

    Control of the swelling, chemical functionalization, and adhesivity of hydrogels are finding new applications in a wide range of material systems. We investigate experimentally the effect of adsorbed particles on hydrogels on the depinning of contact lines. In our experiments, a water drop containing polystyrene microspheres is deposited on a swelling hydrogel, which leads to the drop absorption and particle deposition. Two regimes are observed: a decreasing drop height with a pinned contact line followed by a receding contact line. We show that increasing the particles concentration increases the duration of the first regime and significantly decreases the total absorption time. The adsorbed particles increase the pinning force at the contact line. Finally, we develop a method to measure the receding contact angle with the consideration of the hydrogel swelling. PMID:27185647

  13. Conformational properties of an adsorbed charged polymer.

    PubMed

    Cheng, Chi-Ho; Lai, Pik-Yin

    2005-06-01

    The behavior of a strongly charged polymer adsorbed on an oppositely charged surface of a low-dielectric constant is formulated by the functional integral method. By separating the translational, conformational, and fluctuational degrees of freedom, the scaling behaviors for both the height of the polymer and the thickness of the diffusion layer are determined. Unlike the results predicted by scaling theory, we identified the continuous crossover from the weak compression to the compression regime. All the analytical results are found to be consistent with Monte Carlo simulations. Finally, an alternative (operational) definition of a charged polymer adsorption is proposed. PMID:16089715

  14. Recovery of Technetium Adsorbed on Charcoal

    SciTech Connect

    Engelmann, Mark D.; Metz, Lori A.; Ballou, Nathan E.

    2006-05-01

    Two methods capable of near complete recovery of technetium adsorbed on charcoal are presented. The first involves liquid extraction of the technetium from the charcoal by hot 4M nitric acid. An average recovery of 98% (n=3) is obtained after three rounds of extraction. The second method involves dry ashing with air in a quartz combustion tube at 400-450 C. This method yields an average recovery of 96% (n=5). Other thermal methods were attempted, but resulted in reduced recovery and incomplete material balance

  15. 21 CFR 524.1580 - Nitrofurazone ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Nitrofurazone ophthalmic and topical dosage forms... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.1580 Nitrofurazone ophthalmic and topical dosage forms....

  16. 21 CFR 524.660 - Dimethyl sulfoxide ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Dimethyl sulfoxide ophthalmic and topical dosage... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.660 Dimethyl sulfoxide ophthalmic and topical dosage forms....

  17. 21 CFR 524.390 - Chloramphenicol ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Chloramphenicol ophthalmic and topical dosage... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.390 Chloramphenicol ophthalmic and topical dosage forms....

  18. 21 CFR 524.1200 - Kanamycin ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Kanamycin ophthalmic and topical dosage forms. 524... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.1200 Kanamycin ophthalmic and topical dosage forms....

  19. 21 CFR 524.1600 - Nystatin ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Nystatin ophthalmic and topical dosage forms. 524... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.1600 Nystatin ophthalmic and topical dosage forms....

  20. 21 CFR 524.1484 - Neomycin sulfate ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Neomycin sulfate ophthalmic and topical dosage... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.1484 Neomycin sulfate ophthalmic and topical dosage forms....

  1. The Development of Teaching Efficacy for Drug-Dosage Calculation Instruction: A Nursing Faculty Perspective

    ERIC Educational Resources Information Center

    Vitale, Gail A.

    2011-01-01

    The purpose of this study was to examine how nursing efficacy for drug-dosage calculation instruction is determined. Medication administration is a critical function of nurses in healthcare settings. An essential component of safe medication administration is accurate drug-dosage calculation, but instruction in drug-dosage calculation methods…

  2. 21 CFR 330.3 - Imprinting of solid oral dosage form drug products.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 5 2011-04-01 2011-04-01 false Imprinting of solid oral dosage form drug products... AS SAFE AND EFFECTIVE AND NOT MISBRANDED General Provisions § 330.3 Imprinting of solid oral dosage form drug products. A requirement to imprint an identification code on solid oral dosage form...

  3. 21 CFR 330.3 - Imprinting of solid oral dosage form drug products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 5 2014-04-01 2014-04-01 false Imprinting of solid oral dosage form drug products... AS SAFE AND EFFECTIVE AND NOT MISBRANDED General Provisions § 330.3 Imprinting of solid oral dosage form drug products. A requirement to imprint an identification code on solid oral dosage form...

  4. 21 CFR 330.3 - Imprinting of solid oral dosage form drug products.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 5 2012-04-01 2012-04-01 false Imprinting of solid oral dosage form drug products... AS SAFE AND EFFECTIVE AND NOT MISBRANDED General Provisions § 330.3 Imprinting of solid oral dosage form drug products. A requirement to imprint an identification code on solid oral dosage form...

  5. 21 CFR 330.3 - Imprinting of solid oral dosage form drug products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Imprinting of solid oral dosage form drug products... AS SAFE AND EFFECTIVE AND NOT MISBRANDED General Provisions § 330.3 Imprinting of solid oral dosage form drug products. A requirement to imprint an identification code on solid oral dosage form...

  6. 21 CFR 330.3 - Imprinting of solid oral dosage form drug products.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 5 2013-04-01 2013-04-01 false Imprinting of solid oral dosage form drug products... AS SAFE AND EFFECTIVE AND NOT MISBRANDED General Provisions § 330.3 Imprinting of solid oral dosage form drug products. A requirement to imprint an identification code on solid oral dosage form...

  7. 21 CFR 522.1696 - Penicillin G procaine implantation and injectable dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Penicillin G procaine implantation and injectable dosage forms. 522.1696 Section 522.1696 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... DOSAGE FORM NEW ANIMAL DRUGS § 522.1696 Penicillin G procaine implantation and injectable dosage forms....

  8. 21 CFR 522.1696 - Penicillin G procaine implantation and injectable dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Penicillin G procaine implantation and injectable dosage forms. 522.1696 Section 522.1696 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... DOSAGE FORM NEW ANIMAL DRUGS § 522.1696 Penicillin G procaine implantation and injectable dosage forms....

  9. 21 CFR 522.1696 - Penicillin G procaine implantation and injectable dosage forms.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Penicillin G procaine implantation and injectable dosage forms. 522.1696 Section 522.1696 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... DOSAGE FORM NEW ANIMAL DRUGS § 522.1696 Penicillin G procaine implantation and injectable dosage forms....

  10. 21 CFR 522.1696 - Penicillin G procaine implantation and injectable dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Penicillin G procaine implantation and injectable dosage forms. 522.1696 Section 522.1696 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... DOSAGE FORM NEW ANIMAL DRUGS § 522.1696 Penicillin G procaine implantation and injectable dosage forms....

  11. 21 CFR 522.960 - Flumethasone implantation or injectable dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Flumethasone implantation or injectable dosage... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.960 Flumethasone implantation or injectable dosage forms....

  12. 21 CFR 522.90 - Ampicillin implantation and injectible dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ampicillin implantation and injectible dosage... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.90 Ampicillin implantation and injectible dosage forms....

  13. 21 CFR 524.1662 - Oxytetracycline hydrochloride ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Oxytetracycline hydrochloride ophthalmic and topical dosage forms. 524.1662 Section 524.1662 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... DOSAGE FORM NEW ANIMAL DRUGS § 524.1662 Oxytetracycline hydrochloride ophthalmic and topical dosage forms....

  14. "Soft" metallic contact to isolated C60 molecules.

    PubMed

    Glowatzki, Hendrik; Bröker, Benjamin; Blum, Ralf-Peter; Hofmann, Oliver T; Vollmer, Antje; Rieger, Ralph; Müllen, Klaus; Zojer, Egbert; Rabe, Jürgen P; Koch, Norbert

    2008-11-01

    C60 adsorbed on a monolayer of hexaazatriphenylene-hexanitrile (HATCN) on Ag(111) is investigated by ultraviolet photoelectron spectroscopy (UPS) and scanning tunneling microscopy. UPS and quantum-mechanical modeling show that HATCN chemisorbed on Ag(111) displays metallic character. This metallic molecular layer decouples C60 electronically from the Ag substrate and simultaneously acts both as template for the stable adsorption of isolated C60 molecules at room temperature and as "soft" metallic contact for subsequently deposited molecules. PMID:18954123

  15. Protein adsorption on surfaces: dynamic contact-angle (DCA) and quartz-crystal microbalance (QCM) measurements.

    PubMed

    Stadler, H; Mondon, M; Ziegler, C

    2003-01-01

    Adsorption of the protein bovine serum albumin (BSA) on gold has been tested at various concentrations in aqueous solution by dynamic contact-angle analysis (DCA) and quartz-crystal microbalance (QCM) measurements. With the Wilhelmy plate technique advancing and receding contact angles and the corresponding hysteresis were measured and correlated with the hydrophilicity and the homogeneity of the surface. With electrical admittance measurements of a gold-coated piezoelectrical quartz crystal, layer mass and viscoelastic contributions to the resonator's frequency shift during adsorption could be separated. A correlation was found between the adsorbed mass and the homogeneity and hydrophilicity of the adsorbed film. PMID:12520439

  16. Optimizing heterosurface adsorbent synthesis for liquid chromatography

    NASA Astrophysics Data System (ADS)

    Bogoslovskii, S. Yu.; Serdan, A. A.

    2016-03-01

    The structural and geometric parameters of a silica matrix (SM) for the synthesis of heterosurface adsorbents (HAs) are optimized. Modification is performed by shielding the external surfaces of alkyl-modified silica (AS) using human serum albumin and its subsequent crosslinking. The structural and geometric characteristics of the SM, AS, and HA are measured via low-temperature nitrogen adsorption. It is found that the structural characteristics of AS pores with diameters D < 6 nm do not change during HA synthesis, while the volume of pores with diameters of 6 nm < D < 9 nm shrinks slightly due to the adsorption of albumin in the pore orifices. It is established that the volume of pores with diameters D > 9 nm reduces significantly due to adsorption of albumin. It is concluded that silica gel with a maximum pore size distribution close to 5 nm and a minimal proportion of pores with D > 9 nm is optimal for HA synthesis; this allows us to achieve the greatest similarity between the chromatographic retention parameters for HA and AS. The suitability of the synthesized adsorbents for analyzing drugs in biological fluids through direct sample injection is confirmed by chromatography. It was found that the percentage of the protein fraction detected at the outlet of the chromatographic column is 98%.

  17. Adsorbents as antiendotoxin agents in experimental colitis.

    PubMed Central

    Gardiner, K R; Anderson, N H; McCaigue, M D; Erwin, P J; Halliday, M I; Rowlands, B J

    1993-01-01

    The intestinal mucosa protects the body from a large reservoir of intraluminal pathogenic bacteria and endotoxins. This mucosal barrier is disrupted by the inflammation and ulceration of inflammatory bowel disease and may permit the absorption of toxic bacterial products. Systemic endotoxaemia has been demonstrated in ulcerative colitis and Crohn's disease and correlates with the extent and activity of disease. In this study the efficacy of absorbents as antiendotoxin agents in a hapten induced rat model of colitis is investigated. Induction of colitis was associated with systemic endotoxaemia. Enteral administration of terra fullonica and kaolin, but not of charcoal, significantly reduced systemic endotoxaemia (terra fullonica 4.2 (1.40) pg/ml; kaolin 5.29 (1.86) pg/ml; charcoal 32.7 (16.6) pg/ml; water 39.8 (12.6) pg/ml). Data expressed as mean (SE). With increasing severity of colitis, there was a decreasing ability of adsorbent therapy (terra fullonica) to control systemic endotoxaemia. Enteral administration of adsorbents controls gut derived systemic endotoxaemia in experimental colitis in animals and may be a useful antiendotoxin treatment in patients with inflammatory bowel disease. PMID:8432452

  18. Block copolymer adsorbed layers on solids

    NASA Astrophysics Data System (ADS)

    Sen, Mani; Jiang, Naisheng; Gowd, Bhoje; Endoh, Maya; Koga, Tadanori

    Block copolymer thin films offer a simple and effective route to fabricate highly ordered periodic microdomain structures. The fundamental, yet unsolved question is whether these highly oriented microdomain structures persist even near an impenetrable solid wall. We here report the adsorbed structures of polystyrene-block-poly (4-vinylpyridine) (PS-block-P4VP, Mw = 41,000, PS (weight fraction =0.81) formed on planar silicon substrates. Perpendicularly aligned cylindrical microdomains were created by solvent vapor annealing (Gowd et al., Soft Matter, 2014, 10, 7753), and the adsorbed layer was derived by solvent leaching with chloroform, a good solvent for the polymers and thereafter characterized by using atomic force microscopy, scanning electron microscopy, grazing incidence small angle x-ray scattering, and x-ray reflectivity. The results showed that both PS and P4VP chains lie flat on the substrate, forming a microphase-separated structure (MSS) without long-range order. Moreover, a spin-coated PS-block-P4VP thin film annealed under vacuum at 190 °C showed similar MSS on the substrate, indicating the generality of the interfacial polymer structure. Details will be discussed in the presentation. NSF Grant No. CMMI-1332499.

  19. Mimetite Formation from Goethite-Adsorbed Ions.

    PubMed

    Kleszczewska-Zębala, Anna; Manecki, Maciej; Bajda, Tomasz; Rakovan, John; Borkiewicz, Olaf J

    2016-06-01

    Bioavailability of arsenic in contaminated soils and wastes can be reduced to insignificant levels by precipitation of mimetite Pb5(AsO4)3Cl. The objective of this study is to elucidate mechanisms of the reaction between solution containing lead ions and arsenates adsorbed on synthetic goethite (AsO4-goethite), or arsenate ions in the solution and goethite saturated with adsorbed Pb (Pb-goethite). These reactions, in the presence of Cl, result in rapid crystallization of mimetite. Formation of mimetite is faster than desorption of AsO4 but slower than desorption of Pb from the goethite surface. Slow desorption of arsenates from AsO4-goethite results in heterogeneous precipitation and formation of mimetite incrustation on goethite crystals. Desorption of lead from Pb-goethite is at least as fast as diffusion and advection of AsO4 and Cl in suspension allowing for homogeneous crystallization of mimetite in intergranular solution. Therefore, the mechanism of nucleation is primarily driven by the kinetics of constituent supply to the saturation front, rather than by the thermodynamics of nucleation. The products of the reactions are well documented using microscopy methods such as scanning electron microscopy, electron backscattered diffraction, X-ray diffraction, and Fourier transform infrared spectroscopy. PMID:27329315

  20. The persistence length of adsorbed dendronized polymers.

    PubMed

    Grebikova, Lucie; Kozhuharov, Svilen; Maroni, Plinio; Mikhaylov, Andrey; Dietler, Giovanni; Schlüter, A Dieter; Ullner, Magnus; Borkovec, Michal

    2016-07-21

    The persistence length of cationic dendronized polymers adsorbed onto oppositely charged substrates was studied by atomic force microscopy (AFM) and quantitative image analysis. One can find that a decrease in the ionic strength leads to an increase of the persistence length, but the nature of the substrate and of the generation of the side dendrons influence the persistence length substantially. The strongest effects as the ionic strength is being changed are observed for the fourth generation polymer adsorbed on mica, which is a hydrophilic and highly charged substrate. However, the observed dependence on the ionic strength is much weaker than the one predicted by the Odijk, Skolnik, and Fixman (OSF) theory for semi-flexible chains. Low-generation polymers show a variation with the ionic strength that resembles the one observed for simple and flexible polyelectrolytes in solution. For high-generation polymers, this dependence is weaker. Similar dependencies are found for silica and gold substrates. The observed behavior is probably caused by different extents of screening of the charged groups, which is modified by the polymer generation, and to a lesser extent, the nature of the substrate. For highly ordered pyrolytic graphite (HOPG), which is a hydrophobic and weakly charged substrate, the electrostatic contribution to the persistence length is much smaller. In the latter case, we suspect that specific interactions between the polymer and the substrate also play an important role. PMID:27353115

  1. Photodecomposition of chloromethanes adsorbed on silica surfaces

    NASA Technical Reports Server (NTRS)

    Ausloos, P.; Rebbert, R. E.; Glasgow, L.

    1977-01-01

    Irradiation of CCl4, CFCl3, and CF2Cl2 in the presence of C2H6 in vessels containing silica sand or fused quartz tubing results in the formation of chlorine-containing products. The formation of these compounds occurs at wavelengths extending up to approximately 400 nm, that is, at wavelengths well beyond the absorption threshold of the chloromethanes in the gas phase. It is suggested that CCl4 adsorbed on silica surfaces photodissociates to yield CCl3 and CCl2 species. The poor material balance obtained in these experiments indicates that several of the chlorine-containing fragments are strongly adsorbed on the surface. At a CCl4 pressure of 13 Pa (0.1 torr), photolysis with 366 nm light in the presence of sand results in the decomposition of one molecule for every 10,000 photons striking the surface. Under otherwise identical conditions, the photon-induced breadkdown of CFCl3 and CF2Cl2 is respectively only 10% or 3% as efficient.

  2. Investigation of drug-porous adsorbent interactions in drug mixtures with selected porous adsorbents.

    PubMed

    Madieh, Shadi; Simone, Michael; Wilson, Wendy; Mehra, Dev; Augsburger, Larry

    2007-04-01

    The adsorption of drugs onto porous substrates may prove to be a convenient method by which to enhance the dissolution rate of certain poorly water-soluble drugs in body fluids. The purpose of this research is to provide a better understanding of the type of interactions occurring between drugs and certain pharmaceutically acceptable porous adsorbents that leads to enhanced drug dissolution rates. The interactions between ibuprofen (acidic drug), acetaminophen (acidic drug), dipyridamole (basic drug), and the porous adsorbents used (calcium silicate and silica gel) were investigated using differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier Transform infrared spectroscopy (FTIR). DSC and PXRD results indicated a significant loss of crystallinity of both ibuprofen and acetaminophen but not dipyridamole. In the case of ibuprofen, FTIR results indicated the ionization of the carboxylic group based on the shift in the FTIR carboxylic band. Dissolution of ibuprofen from its mixtures with porous adsorbents was found to be significantly higher compared to the neat drug, whereas dipyridamole dissolution from its mixtures with porous adsorbents was not significantly different from that of the neat drug. PMID:17221849

  3. Equilibrium molecular theory of two-dimensional adsorbate drops on surfaces of heterogeneous adsorbents

    NASA Astrophysics Data System (ADS)

    Tovbin, Yu. K.

    2016-08-01

    A molecular statistical theory for calculating the linear tension of small multicomponent droplets in two-dimensional adsorption systems is developed. The theory describes discrete distributions of molecules in space (on a scale comparable to molecular size) and continuous distributions of molecules (at short distances inside cells) in their translational and vibrational motions. Pair intermolecular interaction potentials (the Mie type potential) in several coordination spheres are considered. For simplicity, it is assumed that distinctions in the sizes of mixture components are slight and comparable to the sizes of adsorbent adsorption centers. Expressions for the pressure tensor components inside small droplets on the heterogeneous surface of an adsorbent are obtained, allowing calculations of the thermodynamic characteristics of a vapor-fluid interface, including linear tension. Problems in refining the molecular theory are discussed: describing the properties of small droplets using a coordination model of their structure, considering the effect an adsorbate has on the state of a near-surface adsorbent region, and the surface heterogeneity factor in the conditions for the formation of droplets.

  4. Colors and contact dermatitis.

    PubMed

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

    2014-01-01

    The diagnosis of skin diseases relies on several clinical signs, among which color is of paramount importance. In this review, we consider certain clinical presentations of both eczematous and noneczematous contact dermatitis in which color plays a peculiar role orientating toward the right diagnosis. The conditions that will be discussed include specific clinical-morphologic subtypes of eczematous contact dermatitis, primary melanocytic, and nonmelanocytic contact hyperchromia, black dermographism, contact chemical leukoderma, and others. Based on the physical, chemical, and biologic factors underlying a healthy skin color, the various skin shades drawing a disease picture are thoroughly debated, stressing their etiopathogenic origins and histopathologic aspects. PMID:25000236

  5. Constructions of contact manifolds

    NASA Astrophysics Data System (ADS)

    Geiges, Hansjörg

    1997-05-01

    1. IntroductionIt has been known for some time that contact structures show a high degree of topological flexibility in the sense that many topological operations can be performed on contact manifolds while preserving the contact property. For instance, Martinet [14] used a surgery description of 3-manifolds to show that every closed, oriented 3-manifold admits a contact structure, and alternative proofs of this result were given later by Thurston and Winkelnkemper [18], who based their proof on an open book decomposition, and Gonzalo [8], who used branched covers. These, however, are all strictly 3-dimensional constructions.

  6. Optical contact micrometer

    DOEpatents

    Jacobson, Steven D.

    2014-08-19

    Certain examples provide optical contact micrometers and methods of use. An example optical contact micrometer includes a pair of opposable lenses to receive an object and immobilize the object in a position. The example optical contact micrometer includes a pair of opposable mirrors positioned with respect to the pair of lenses to facilitate viewing of the object through the lenses. The example optical contact micrometer includes a microscope to facilitate viewing of the object through the lenses via the mirrors; and an interferometer to obtain one or more measurements of the object.

  7. Rapid enrichment of rare-earth metals by carboxymethyl cellulose-based open-cellular hydrogel adsorbent from HIPEs template.

    PubMed

    Zhu, Yongfeng; Wang, Wenbo; Zheng, Yian; Wang, Feng; Wang, Aiqin

    2016-04-20

    A series of monolithic open-cellular hydrogel adsorbents based on carboxymethylcellulose (CMC) were prepared through high internal phase emulsions (HIPEs) and used to enrich the rare-earth metals La(3+) and Ce(3+). The changes of pore structure, and the effects of pH, contact time, initial concentration on the adsorption performance were systematically studied. The results show that the as-prepared monolithic hydrogel adsorbents possess good open-cellular framework structure and have fast adsorption kinetics and high adsorption capacity for La(3+) and Ce(3+). The involved adsorption system can reach equilibrium within 30min and the maximal adsorption capacity is determined to be 384.62mg/g for La(3+) and 333.33mg/g for Ce(3+). Moreover, these porous hydrogel adsorbents show an excellent adsorptive reusability for La(3+) and Ce(3+) through five adsorption-desorption cycles. Such a pore hierarchy structure makes this monolithic open-cellular hydrogel adsorbent be an effective adsorbent for effective enrichment of La(3+) and Ce(3+) from aqueous solution. PMID:26876827

  8. Impact of temperature and electrical potentials on the stability and structure of collagen adsorbed on the gold electrode

    NASA Astrophysics Data System (ADS)

    Meiners, Frank; Ahlers, Michael; Brand, Izabella; Wittstock, Gunther

    2015-01-01

    The morphology and structure of collagen type I adsorbed on gold electrodes were studied as a function of electrode potential and temperature by means of capacitance measurements, polarization modulation infrared reflection-absorption spectroscopy and scanning force microscopy at temperatures of 37 °C, 43 °C and 50 °C. The selected temperatures corresponded to the normal body temperature, temperature of denaturation of collagen molecules and denaturation of collagen fibrils, respectively. Independently of the solution temperature, collagen was adsorbed on gold electrodes in the potential range - 0.7 V < E < 0.4 V vs. Ag/AgCl, where the protein film was very stable. Fragments of collagen molecules made a direct contact to the gold surface and water was present in the film. Protein molecules were oriented preferentially with their long axis towards the gold surface. Collagen molecules in the adsorbed state preserved their native triple helical structure even at temperatures corresponding to collagen denaturation in aqueous solutions. Application of E < - 0.75 V vs. Ag/AgCl leads to the swelling of the protein film by water and desorption from the electrode surface. IR spectra provided no evidence of the thermal denaturation of adsorbed collagen molecules. A temperature increase to 50 °C leads to a distortion of the collagen film. The processes of aggregation and fibrilization were preferred over thermal denaturation for collagen adsorbed on the electrode surface and exposed to changing potentials.

  9. Development of a new adsorbent from agro-industrial waste and its potential use in endocrine disruptor compound removal.

    PubMed

    Rovani, Suzimara; Censi, Monique T; Pedrotti, Sidnei L; Lima, Eder C; Cataluña, Renato; Fernandes, Andreia N

    2014-04-30

    A new activated carbon (AC) material was prepared by pyrolysis of a mixture of coffee grounds, eucalyptus sawdust, calcium hydroxide and soybean oil at 800°C. This material was used as adsorbent for the removal of the endocrine disruptor compounds 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) from aqueous solutions. The carbon material was characterized by scanning electron microscopy (SEM), infrared spectroscopy (FTIR), N2 adsorption/desorption curves and point of zero charge (pHPZC). Variables including the initial pH of the adsorbate solutions, adsorbent masses and contact time were optimized. The optimum range of initial pH for removal of endocrine disruptor compounds (EDC) was 2.0-11.0. The kinetics of adsorption were investigated using general order, pseudo first-order and pseudo-second order kinetic models. The Sips isotherm model gave the best fits of the equilibrium data (298K). The maximum amounts of E2 and EE2 removed at 298K were 7.584 (E2) and 7.883mgg(-1) (EE2) using the AC as adsorbent. The carbon adsorbent was employed in SPE (solid phase extraction) of E2 and EE2 from aqueous solutions. PMID:24647264

  10. Electrochemically adsorbed Pb on Ag (111) studied with grazing- incidence x-ray scattering

    SciTech Connect

    Kortright, J.B.; Ross, P.N.; Melroy, O.R.; Toney, M.F.; Borges, G.L.; Samant, M.G.

    1989-04-01

    Grazing-incidence x-ray scattering studies of the evolution of electrochemically deposited layers of lead on silver (111) as a function of applied electrochemical potential are presented. Measurements were made with the adsorbed layers in contact with solution in a specially designed sample cell. The observed lead structures are a function of the applied potential and range from an incommensurate monolayer, resulting from underpotential deposition, to randomly oriented polycrystalline bulk lead, resulting from lower deposition potentials. These early experiments demonstrate the ability of in situ x-ray diffraction measurements to determine structures associated with electrochemical deposition. 6 refs., 4 figs.

  11. Adsorbent Alkali Conditioning for Uranium Adsorption from Seawater. Adsorbent Performance and Technology Cost Evaluation

    SciTech Connect

    Tsouris, Costas; Mayes, Richard T.; Janke, Christopher James; Dai, Sheng; Das, S.; Liao, W. -P.; Kuo, Li-Jung; Wood, Jordana; Gill, Gary; Byers, Maggie Flicker; Schneider, Eric

    2015-09-30

    The Fuel Resources program of the Fuel Cycle Research and Development program of the Office of Nuclear Energy (NE) is focused on identifying and implementing actions to assure that nuclear fuel resources are available in the United States. An immense source of uranium is seawater, which contains an estimated amount of 4.5 billion tonnes of dissolved uranium. This unconventional resource can provide a price cap and ensure centuries of uranium supply for future nuclear energy production. NE initiated a multidisciplinary program with participants from national laboratories, universities, and research institutes to enable technical breakthroughs related to uranium recovery from seawater. The goal is to develop advanced adsorbents to reduce the seawater uranium recovery technology cost and uncertainties. Under this program, Oak Ridge National Laboratory (ORNL) has developed a new amidoxime-based adsorbent of high surface area, which tripled the uranium capacity of leading Japanese adsorbents. Parallel efforts have been focused on the optimization of the physicochemical and operating parameters used during the preparation of the adsorbent for deployment. A set of parameters that need to be optimized are related to the conditioning of the adsorbent with alkali solution, which is necessary prior to adsorbent deployment. Previous work indicated that alkali-conditioning parameters significantly affect the adsorbent performance. Initiated in 2014, this study had as a goal to determine optimal parameters such as base type and concentration, temperature, and duration of conditioning that maximize the uranium adsorption performance of amidoxime functionalized adsorbent, while keeping the cost of uranium production low. After base-treatment at various conditions, samples of adsorbent developed at ORNL were tested in this study with batch simulated seawater solution of 8-ppm uranium concentration, batch seawater spiked with uranium nitrate at 75-100 ppb uranium, and continuous

  12. Gene Expression Dosage Regulation in an Allopolyploid Fish

    PubMed Central

    Matos, I; Machado, M. P.; Schartl, M.; Coelho, M. M.

    2015-01-01

    How allopolyploids are able not only to cope but profit from their condition is a question that remains elusive, but is of great importance within the context of successful allopolyploid evolution. One outstanding example of successful allopolyploidy is the endemic Iberian cyprinid Squalius alburnoides. Previously, based on the evaluation of a few genes, it was reported that the transcription levels between diploid and triploid S. alburnoides were similar. If this phenomenon occurs on a full genomic scale, a wide functional ‘‘diploidization’’ could be related to the success of these polyploids. We generated RNA-seq data from whole juvenile fish and from adult livers, to perform the first comparative quantitative transcriptomic analysis between diploid and triploid individuals of a vertebrate allopolyploid. Together with an assay to estimate relative expression per cell, it was possible to infer the relative sizes of transcriptomes. This showed that diploid and triploid S. alburnoides hybrids have similar liver transcriptome sizes. This in turn made it valid to directly compare the S. alburnoides RNA-seq transcript data sets and obtain a profile of dosage responses across the S. alburnoides transcriptome. We found that 64% of transcripts in juveniles’ samples and 44% in liver samples differed less than twofold between diploid and triploid hybrids (similar expression). Yet, respectively 29% and 15% of transcripts presented accurate dosage compensation (PAA/PA expression ratio of 1 instead of 1.5). Therefore, an exact functional diploidization of the triploid genome does not occur, but a significant down regulation of gene expression in triploids was observed. However, for those genes with similar expression levels between diploids and triploids, expression is not globally strictly proportional to gene dosage nor is it set to a perfect diploid level. This quantitative expression flexibility may be a strong contributor to overcome the genomic shock, and be an

  13. X-marks the spot: X-chromosome identification during dosage compensation☆

    PubMed Central

    Chery, Jessica; Larschan, Erica

    2016-01-01

    Dosage compensation is the essential process that equalizes the dosage of X-linked genes between the sexes in heterogametic species. Because all of the genes along the length of a single chromosome are co-regulated, dosage compensation serves as a model system for understanding how domains of coordinate gene regulation are established. Dosage compensation has been best studied in mammals, flies and worms. Although dosage compensation systems are seemingly diverse across species, there are key shared principles of nucleation and spreading that are critical for accurate targeting of the dosage compensation complex to the X-chromosome(s). We will highlight the mechanisms by which long non-coding RNAs function together with DNA sequence elements to tether dosage compensation complexes to the X-chromosome. This article is part of a Special Issue entitled: Chromatin and epigenetic regulation of animal development. PMID:24406325

  14. Fundamental characteristics of synthetic adsorbents intended for industrial chromatographic separations.

    PubMed

    Adachi, Tadashi; Isobe, Eiji

    2004-05-14

    With the aim of obtaining comprehensive information on the selection of synthetic adsorbents for industrial applications, effect of pore and chemical structure of industrial-grade synthetic adsorbents on adsorption capacity of several pharmaceutical compounds was investigated. For relatively low molecular mass compounds, such as cephalexin, berberine chloride and tetracycline hydrochloride, surface area per unit volume of polystyrenic adsorbents dominated the equilibrium adsorption capacity. On the contrary, effect of pore size of the polystyrenic adsorbents on the equilibrium adsorption capacity was observed for relatively high molecular mass compounds, such as rifampicin, Vitamin B12 and insulin. Polystyrenic adsorbent with high surface area and small pore size showed small adsorption capacity for relatively high molecular mass compounds, whereas polystyrenic adsorbent with relatively small surface area but with large pore size showed large adsorption capacity. Effect of chemical structure on the equilibrium adsorption capacity of several pharmaceutical compounds was also studied among polystyrenic, modified polystyrenic and polymethacrylic adsorbents. The modified polystyrenic adsorbent showed larger adsorption capacity for all compounds tested in this study due to enhanced hydrophobicity. The polymethacrylic adsorbent possessed high adsorption capacity for rifampicin and insulin, but it showed lower adsorption capacity for the other compounds studied. This result may be attributed to hydrogen bonding playing major role for the adsorption of compounds on polymethacrylic adsorbent. Furthermore, column adsorption experiments were operated to estimate the effect of pore characteristics of the polystyrenic adsorbents on dynamic adsorption behavior, and it is found that both surface area and pore size of the polystyrenic adsorbents significantly affect the dynamic adsorption capacity as well as flow rate. PMID:15139411

  15. Language Contact: An Introduction.

    ERIC Educational Resources Information Center

    Thomason, Sarah G.

    This book surveys situations in which language contact arises and focuses on what happens to the languages themselves: sometimes nothing, sometimes the incorporation of new words, sometimes the spread of new sounds and sentence structures across many languages and wide swathes of territory. It outlines the origins and results of contact-induced…

  16. Miniature intermittent contact switch

    NASA Technical Reports Server (NTRS)

    Sword, A.

    1972-01-01

    Design of electric switch for providing intermittent contact is presented. Switch consists of flexible conductor surrounding, but separated from, fixed conductor. Flexing of outside conductor to contact fixed conductor completes circuit. Advantage is small size of switch compared to standard switches.

  17. Video STM Studies of Adsorbate Diffusion at Electrochemical Interfaces

    NASA Astrophysics Data System (ADS)

    Tansel, T.; Magnussen, O. M.

    2006-01-01

    Direct in situ studies of the surface diffusion of isolated adsorbates at an electrochemical interface by high-speed scanning tunneling microscopy (video STM) are presented for sulfide adsorbates on Cu(100) in HCl solution. As revealed by a quantitative statistical analysis, the adsorbate motion can be described by thermally activated hopping between neighboring adsorption sites with an activation energy that increases linearly with electrode potential by 0.50 eV per V. This can be explained by changes in the adsorbate dipole moment during the hopping process and contributions from coadsorbates.

  18. Noneczematous Contact Dermatitis

    PubMed Central

    Foti, Caterina; Vestita, Michelangelo; Angelini, Gianni

    2013-01-01

    Irritant or allergic contact dermatitis usually presents as an eczematous process, clinically characterized by erythematoedematovesicous lesions with intense itching in the acute phase. Such manifestations become erythematous-scaly as the condition progresses to the subacute phase and papular-hyperkeratotic in the chronic phase. Not infrequently, however, contact dermatitis presents with noneczematous features. The reasons underlying this clinical polymorphism lie in the different noxae and contact modalities, as well as in the individual susceptibility and the various targeted cutaneous structures. The most represented forms of non-eczematous contact dermatitis include the erythema multiforme-like, the purpuric, the lichenoid, and the pigmented kinds. These clinical entities must obviously be discerned from the corresponding “pure” dermatitis, which are not associated with contact with exogenous agents. PMID:24109520

  19. Electrical Contacts to Nanomaterials.

    PubMed

    Bandaru, P R; Faraby, H; DiBattista, M

    2015-12-01

    The efficient passage of electrical current from an external contact to a nanomaterial is necessary for harnessing characteristics unique to the nanoscale, such as those relevant to energy quantization. However, an intrinsic resistance pertinent to dimensionality crossover and the presence of impurities precludes optimal electrical contact formation. In this review, we first discuss the relevant principles and contact resistance measurement methodologies, with modifications necessary for the nanoscale. Aspects related to the deposition of the contact material are deemed to be crucial. Consequently, the use of focused ion beam (FIB) based deposition, which relies on the ion-induced decomposition of a metallorganic precursor, and which has been frequently utilized for nanoscale contacts is considered in detail. PMID:26682353

  20. Linear transport models for adsorbing solutes

    NASA Astrophysics Data System (ADS)

    Roth, K.; Jury, W. A.

    1993-04-01

    A unified linear theory for the transport of adsorbing solutes through soils is presented and applied to analyze movement of napropamide through undisturbed soil columns. The transport characteristics of the soil are expressed in terms of the travel time distribution of the mobile phase which is then used to incorporate local interaction processes. This approach permits the analysis of all linear transport processes, not only the small subset for which a differential description is known. From a practical point of view, it allows the direct use of measured concentrations or fluxes of conservative solutes to characterize the mobile phase without first subjecting them to any model. For complicated flow regimes, this may vastly improve the identification of models and estimation of their parameters for the local adsorption processes.

  1. The persistence length of adsorbed dendronized polymers

    NASA Astrophysics Data System (ADS)

    Grebikova, Lucie; Kozhuharov, Svilen; Maroni, Plinio; Mikhaylov, Andrey; Dietler, Giovanni; Schlüter, A. Dieter; Ullner, Magnus; Borkovec, Michal

    2016-07-01

    The persistence length of cationic dendronized polymers adsorbed onto oppositely charged substrates was studied by atomic force microscopy (AFM) and quantitative image analysis. One can find that a decrease in the ionic strength leads to an increase of the persistence length, but the nature of the substrate and of the generation of the side dendrons influence the persistence length substantially. The strongest effects as the ionic strength is being changed are observed for the fourth generation polymer adsorbed on mica, which is a hydrophilic and highly charged substrate. However, the observed dependence on the ionic strength is much weaker than the one predicted by the Odijk, Skolnik, and Fixman (OSF) theory for semi-flexible chains. Low-generation polymers show a variation with the ionic strength that resembles the one observed for simple and flexible polyelectrolytes in solution. For high-generation polymers, this dependence is weaker. Similar dependencies are found for silica and gold substrates. The observed behavior is probably caused by different extents of screening of the charged groups, which is modified by the polymer generation, and to a lesser extent, the nature of the substrate. For highly ordered pyrolytic graphite (HOPG), which is a hydrophobic and weakly charged substrate, the electrostatic contribution to the persistence length is much smaller. In the latter case, we suspect that specific interactions between the polymer and the substrate also play an important role.The persistence length of cationic dendronized polymers adsorbed onto oppositely charged substrates was studied by atomic force microscopy (AFM) and quantitative image analysis. One can find that a decrease in the ionic strength leads to an increase of the persistence length, but the nature of the substrate and of the generation of the side dendrons influence the persistence length substantially. The strongest effects as the ionic strength is being changed are observed for the fourth

  2. Can we reduce the dosage of biologics in spondyloarthritis?

    PubMed

    Olivieri, Ignazio; D'Angelo, Salvatore; Padula, Angela; Leccese, Pietro; Nigro, Angelo; Palazzi, Carlo

    2013-05-01

    TNF blockers have revolutionized the management of spondyloarthritis (SpA). To date, four anti-TNFα agents (etanercept, infliximab, adalimumab, golimumab) have been approved for the management of ankylosing spondylitis (AS) and psoriatic arthritis (PsA). The first objective in the management of AS and PsA with TNF inhibitors is to reduce disease activity to clinical remission or low disease activity. After remission has been achieved, this state should be maintained as long as possible. However, the financial burden associated with the cost of anti-TNF agents as well as concerns about their long-term safety suggest reducing the dosage of the drug or discontinuing the therapy in the hopes of drug-free remission. The aim of this review is to examine what has, till now, been published on this topic in axial SpA, which includes AS and non-radiographic axial SpA (nr-axSpA), peripheral SpA and PsA. Discontinuation of therapy in axial SpA is not possible in the majority of patients, while on the contrary, reducing the dosage often is. In some patients with peripheral SpA and PsA it is also possible to discontinue therapy and to achieve drug-free remission. PMID:22940233

  3. Gene Dosage Imbalance Contributes to Chromosomal Instability-Induced Tumorigenesis.

    PubMed

    Clemente-Ruiz, Marta; Murillo-Maldonado, Juan M; Benhra, Najate; Barrio, Lara; Pérez, Lidia; Quiroga, Gonzalo; Nebreda, Angel R; Milán, Marco

    2016-02-01

    Chromosomal instability (CIN) is thought to be a source of mutability in cancer. However, CIN often results in aneuploidy, which compromises cell fitness. Here, we used the dosage compensation mechanism (DCM) of Drosophila to demonstrate that chromosome-wide gene dosage imbalance contributes to the deleterious effects of CIN-induced aneuploidy and its pro-tumorigenic action. We present evidence that resetting of the DCM counterbalances the damaging effects caused by CIN-induced changes in X chromosome number. Importantly, interfering with the DCM suffices to mimic the cellular effects of aneuploidy in terms of reactive oxygen species (ROS) production, JNK-dependent cell death, and tumorigenesis upon apoptosis inhibition. We unveil a role of ROS in JNK activation and a variety of cellular and tissue-wide mechanisms that buffer the deleterious effects of CIN, including DNA-damage repair, activation of the p38 pathway, and cytokine induction to promote compensatory proliferation. Our data reveal the existence of robust compensatory mechanisms that counteract CIN-induced cell death and tumorigenesis. PMID:26859353

  4. Maintenance and Loss of Duplicated Genes by Dosage Subfunctionalization.

    PubMed

    Gout, Jean-Francois; Lynch, Michael

    2015-08-01

    Whole-genome duplications (WGDs) have contributed to gene-repertoire enrichment in many eukaryotic lineages. However, most duplicated genes are eventually lost and it is still unclear why some duplicated genes are evolutionary successful whereas others quickly turn to pseudogenes. Here, we show that dosage constraints are major factors opposing post-WGD gene loss in several Paramecium species that share a common ancestral WGD. We propose a model where a majority of WGD-derived duplicates preserve their ancestral function and are retained to produce enough of the proteins performing this same ancestral function. Under this model, the expression level of individual duplicated genes can evolve neutrally as long as they maintain a roughly constant summed expression, and this allows random genetic drift toward uneven contributions of the two copies to total expression. Our analysis suggests that once a high level of imbalance is reached, which can require substantial lengths of time, the copy with the lowest expression level contributes a small enough fraction of the total expression that selection no longer opposes its loss. Extension of our analysis to yeast species sharing a common ancestral WGD yields similar results, suggesting that duplicated-gene retention for dosage constraints followed by divergence in expression level and eventual deterministic gene loss might be a universal feature of post-WGD evolution. PMID:25908670

  5. Emergence of 3D Printed Dosage Forms: Opportunities and Challenges.

    PubMed

    Alhnan, Mohamed A; Okwuosa, Tochukwu C; Sadia, Muzna; Wan, Ka-Wai; Ahmed, Waqar; Arafat, Basel

    2016-08-01

    The recent introduction of the first FDA approved 3D-printed drug has fuelled interest in 3D printing technology, which is set to revolutionize healthcare. Since its initial use, this rapid prototyping (RP) technology has evolved to such an extent that it is currently being used in a wide range of applications including in tissue engineering, dentistry, construction, automotive and aerospace. However, in the pharmaceutical industry this technology is still in its infancy and its potential yet to be fully explored. This paper presents various 3D printing technologies such as stereolithographic, powder based, selective laser sintering, fused deposition modelling and semi-solid extrusion 3D printing. It also provides a comprehensive review of previous attempts at using 3D printing technologies on the manufacturing dosage forms with a particular focus on oral tablets. Their advantages particularly with adaptability in the pharmaceutical field have been highlighted, which enables the preparation of dosage forms with complex designs and geometries, multiple actives and tailored release profiles. An insight into the technical challenges facing the different 3D printing technologies such as the formulation and processing parameters is provided. Light is also shed on the different regulatory challenges that need to be overcome for 3D printing to fulfil its real potential in the pharmaceutical industry. PMID:27194002

  6. RFID Tag Helix Antenna Sensors for Wireless Drug Dosage Monitoring

    PubMed Central

    Huang, Haiyu; Zhao, Peisen; Chen, Pai-Yen; Ren, Yong; Liu, Xuewu; Ferrari, Mauro; Hu, Ye; Akinwande, Deji

    2014-01-01

    Miniaturized helix antennas are integrated with drug reservoirs to function as RFID wireless tag sensors for real-time drug dosage monitoring. The general design procedure of this type of biomedical antenna sensors is proposed based on electromagnetic theory and finite element simulation. A cost effective fabrication process is utilized to encapsulate the antenna sensor within a biocompatible package layer using PDMS material, and at the same time form a drug storage or drug delivery unit inside the sensor. The in vitro experiment on two prototypes of antenna sensor-drug reservoir assembly have shown the ability to monitor the drug dosage by tracking antenna resonant frequency shift from 2.4–2.5-GHz ISM band with realized sensitivity of 1.27 \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}$\\mu~{\\rm l}/{\\rm MHz}$\\end{document} for transdermal drug delivery monitoring and 2.76-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}$\\mu~{\\rm l}/{\\rm MHz}$\\end{document} sensitivity for implanted drug delivery monitoring. PMID:27170865

  7. Evaluation of the dosage of ivermectin in falcons.

    PubMed

    Lierz, M

    2001-05-12

    Twelve groups of falcons, each containing three female gyrfalcon-peregrine falcon hybrids (Falco rusticolus x Falco peregrinus) were injected intramuscularly with a single dose of ivermectin ranging from 0.2 mg/kg to 11 mg/kg bodyweight, and a control group was injected with water. Doses of ivermectin between 0.2 and 5 mg/kg failed to produce clinical signs of illness in the birds. Four birds which received either 6, 7 or 8 mg/kg showed slight clinical signs, and all the birds receiving 9 to 11 mg/kg showed more or less severe clinical signs of anorexia, apathy and sedation. Slight changes in the mean plasma activities of aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase (AP) were detected in the group dosed with 5 mg/kg, and higher dosages caused marked changes in these enzymes as well as in the mean plasma activity of lactate dehydrogenase. The mean activity of AP decreased, and the activities of the other enzymes increased. A dosage of 2 to 3 mg/kg ivermectin is recommended as a safe and effective antiparasitic drug for falcons and it has been used successfully to treat infestations of Serratospiculum species. PMID:11386446

  8. Chiral recognition in dimerization of adsorbed cysteine observed by scanning tunnelling microscopy

    NASA Astrophysics Data System (ADS)

    Kühnle, Angelika; Linderoth, Trolle R.; Hammer, Bjørk; Besenbacher, Flemming

    2002-02-01

    Stereochemistry plays a central role in controlling molecular recognition and interaction: the chemical and biological properties of molecules depend not only on the nature of their constituent atoms but also on how these atoms are positioned in space. Chiral specificity is consequently fundamental in chemical biology and pharmacology and has accordingly been widely studied. Advances in scanning probe microscopies now make it possible to probe chiral phenomena at surfaces at the molecular level. These methods have been used to determine the chirality of adsorbed molecules, and to provide direct evidence for chiral discrimination in molecular interactions and the spontaneous resolution of adsorbates into extended enantiomerically pure overlayers. Here we report scanning tunnelling microscopy studies of cysteine adsorbed to a (110) gold surface, which show that molecular pairs formed from a racemic mixture of this naturally occurring amino acid are exclusively homochiral, and that their binding to the gold surface is associated with local surface restructuring. Density-functional theory calculations indicate that the chiral specificity of the dimer formation process is driven by the optimization of three bonds on each cysteine molecule. These findings thus provide a clear molecular-level illustration of the well known three-point contact model for chiral recognition in a simple bimolecular system.

  9. Untangleing the effects of chain rigidity on the structure and dynamics of strongly adsorbed polymer melts

    SciTech Connect

    Carrillo, Jan-Michael Y.; Cheng, Shiwang; Kumar, Rajeev; Goswami, Monojoy; Sokolov, Alexei P; Sumpter, Bobby G.

    2015-06-11

    Here, we present a detailed analysis of coarse-grained molecular dynamics simulations of semiflexible polymer melts in contact with a strongly adsorbing substrate. We have characterized the segments in the interfacial layer by counting the number of trains, loops, tails and unadsorbed segments. For more rigid chains, a tail and an adsorbed segment (a train) dominate while loops are more prevalent in more flexible chains. The tails exhibit a non-uniformly stretched conformation akin to the polydispersed pseudobrush envisioned by Guiselin. To probe the dynamics of the segments we computed the layer z-resolved intermediate coherent collective dynamics structure factor, S(q, t, z), mean-square displacement of segments, and the 2nd Legendre polynomial of the time-autocorrelation of unit bond vectors, 2[ni(t,z)•ni(0,z)]>. Our results show that segmental dynamics is slower for stiffer chains and there is a strong correlation between the structure and dynamics in the interfacial layer. There is no glassy layer, and the slowing down in dynamics of stiffer chains in the adsorbed region can be attributed to the densification and the more persistent layering of segments.

  10. Untangleing the effects of chain rigidity on the structure and dynamics of strongly adsorbed polymer melts

    DOE PAGESBeta

    Carrillo, Jan-Michael Y.; Cheng, Shiwang; Kumar, Rajeev; Goswami, Monojoy; Sokolov, Alexei P; Sumpter, Bobby G.

    2015-06-11

    Here, we present a detailed analysis of coarse-grained molecular dynamics simulations of semiflexible polymer melts in contact with a strongly adsorbing substrate. We have characterized the segments in the interfacial layer by counting the number of trains, loops, tails and unadsorbed segments. For more rigid chains, a tail and an adsorbed segment (a train) dominate while loops are more prevalent in more flexible chains. The tails exhibit a non-uniformly stretched conformation akin to the polydispersed pseudobrush envisioned by Guiselin. To probe the dynamics of the segments we computed the layer z-resolved intermediate coherent collective dynamics structure factor, S(q, t, z),more » mean-square displacement of segments, and the 2nd Legendre polynomial of the time-autocorrelation of unit bond vectors, 2[ni(t,z)•ni(0,z)]>. Our results show that segmental dynamics is slower for stiffer chains and there is a strong correlation between the structure and dynamics in the interfacial layer. There is no glassy layer, and the slowing down in dynamics of stiffer chains in the adsorbed region can be attributed to the densification and the more persistent layering of segments.« less

  11. Thermal and Electronic Fluctuations of Flexible Adsorbed Molecules: Azobenzene on Ag(111)

    NASA Astrophysics Data System (ADS)

    Maurer, Reinhard J.; Liu, Wei; Poltavsky, Igor; Stecher, Thomas; Oberhofer, Harald; Reuter, Karsten; Tkatchenko, Alexandre

    2016-04-01

    We investigate the thermal and electronic collective fluctuations that contribute to the finite-temperature adsorption properties of flexible adsorbates on surfaces on the example of the molecular switch azobenzene C12 H10 N2 on the Ag(111) surface. Using first-principles molecular dynamics simulations, we obtain the free energy of adsorption that accurately accounts for entropic contributions, whereas the inclusion of many-body dispersion interactions accounts for the electronic correlations that govern the adsorbate binding. We find the adsorbate properties to be strongly entropy driven, as can be judged by a kinetic molecular desorption prefactor of 1024 s-1 that largely exceeds previously reported estimates. We relate this effect to sizable fluctuations across structural and electronic observables. A comparison of our calculations to temperature-programed desorption measurements demonstrates that finite-temperature effects play a dominant role for flexible molecules in contact with polarizable surfaces, and that recently developed first-principles methods offer an optimal tool to reveal novel collective behavior in such complex systems.

  12. Thermal and Electronic Fluctuations of Flexible Adsorbed Molecules: Azobenzene on Ag(111).

    PubMed

    Maurer, Reinhard J; Liu, Wei; Poltavsky, Igor; Stecher, Thomas; Oberhofer, Harald; Reuter, Karsten; Tkatchenko, Alexandre

    2016-04-01

    We investigate the thermal and electronic collective fluctuations that contribute to the finite-temperature adsorption properties of flexible adsorbates on surfaces on the example of the molecular switch azobenzene C_{12}H_{10}N_{2} on the Ag(111) surface. Using first-principles molecular dynamics simulations, we obtain the free energy of adsorption that accurately accounts for entropic contributions, whereas the inclusion of many-body dispersion interactions accounts for the electronic correlations that govern the adsorbate binding. We find the adsorbate properties to be strongly entropy driven, as can be judged by a kinetic molecular desorption prefactor of 10^{24}  s^{-1} that largely exceeds previously reported estimates. We relate this effect to sizable fluctuations across structural and electronic observables. A comparison of our calculations to temperature-programed desorption measurements demonstrates that finite-temperature effects play a dominant role for flexible molecules in contact with polarizable surfaces, and that recently developed first-principles methods offer an optimal tool to reveal novel collective behavior in such complex systems. PMID:27104719

  13. Anomalous conformational transitions in cytochrome C adsorbing to Langmuir-Blodgett films

    NASA Astrophysics Data System (ADS)

    Sankaranarayanan, Kamatchi; Nair, B. U.; Dhathathreyan, A.

    2013-05-01

    Helix to beta conformational transitions in proteins has attracted much attention due to their relevance to fibril formation which is implicated in many neurological diseases. This study reports on unusual conformational transition of cytochrome C adsorbing to hydrophilic surface containing pure cationic lipid and mixed Langmuir-Blodgett films (LB films) of cationic and neutral lipids. Evidence for conformational changes of the protein from its native helical state to beta sheet comes from Circular dichroic spectroscopy (CD spectroscopy). Analysis of these samples using High resolution TEM (HRTEM) shows a typical fibrillar pattern with each strand spacing of about 0.41 nm across which can be attributed to the repeat distance of interdigitated neighboring hydrogen-bonded ribbons in a beta sheet. Changes in contact angles of protein adsorbing to the LB films together with the increased mass uptake of water using quartz crystal microbalance (QCM) confirm the role of positive charges in the conformational transition. Dehydration of the protein resulting from the excess water entrainment in the polar planes of the cationic lipid in hydrophilic surface seems to trigger the refolding of the protein to beta sheet while it retains its native conformation in hydrophobic films. The results suggest that drastic conformational changes in CytC adsorbing to cationic lipids may be of significance in its role as a peripheral membrane protein.

  14. Low-Friction Adsorbed Layers of a Triblock Copolymer Additive in Oil-Based Lubrication.

    PubMed

    Yamada, Shinji; Fujihara, Ami; Yusa, Shin-ichi; Tanabe, Tadao; Kurihara, Kazue

    2015-11-10

    The tribological properties of the dilute solution of an ABA triblock copolymer, poly(11-acrylamidoundecanoic acid)-block-poly(stearyl methacrylate)-block-poly(11-acrylamidoundecanoic acid (A5S992A5), in poly(α-olefin) (PAO) confined between mica surfaces were investigated using the surface forces apparatus (SFA). Friction force was measured as a function of applied load and sliding velocity, and the film thickness and contact geometry during sliding were analyzed using the fringes of equal chromatic order (FECO) in the SFA. The results were contrasted with those of confined PAO films; the effects of the addition of A5S992A5 on the tribological properties were discussed. The thickness of the A5S992A5/PAO system varied with time after surface preparation and with repetitive sliding motions. The thickness was within the range from 40 to 70 nm 1 day after preparation (the Day1 film), and was about 20 nm on the following day (the Day2 film). The thickness of the confined PAO film was thinner than 1.4 nm, indicating that the A5S992A5/PAO system formed thick adsorbed layers on mica surfaces. The friction coefficient was about 0.03 to 0.04 for the Day1 film and well below 0.01 for the Day2 film, which were 1 or 2 orders of magnitude lower than the values for the confined PAO films. The time dependent changes of the adsorbed layer thickness and friction properties should be caused by the relatively low solubility of A5S992A5 in PAO. The detailed analysis of the contact geometry and friction behaviors implies that the particularly low friction of the Day2 film originates from the following factors: (i) shrinkage of the A5S992A5 molecules (mainly the poly(stearyl methacrylate) blocks) that leads to a viscoelastic properties of the adsorbed layers; and (ii) the intervening PAO layer between the adsorbed polymer layers that constitutes a high-fluidity sliding interface. Our results suggest that the block copolymer having relatively low solubility in a lubricant base oil is

  15. Telescopic vision contact lens

    NASA Astrophysics Data System (ADS)

    Tremblay, Eric J.; Beer, R. Dirk; Arianpour, Ashkan; Ford, Joseph E.

    2011-03-01

    We present the concept, optical design, and first proof of principle experimental results for a telescopic contact lens intended to become a visual aid for age-related macular degeneration (AMD), providing magnification to the user without surgery or external head-mounted optics. Our contact lens optical system can provide a combination of telescopic and non-magnified vision through two independent optical paths through the contact lens. The magnified optical path incorporates a telescopic arrangement of positive and negative annular concentric reflectors to achieve 2.8x - 3x magnification on the eye, while light passing through a central clear aperture provides unmagnified vision.

  16. Optical contacting of quartz

    NASA Technical Reports Server (NTRS)

    Payne, L. L.

    1982-01-01

    The strength of the bond between optically contacted quartz surfaces was investigated. The Gravity Probe-B (GP-B) experiment to test the theories of general relativity requires extremely precise measurements. The quartz components of the instruments to make these measurements must be held together in a very stable unit. Optical contacting is suggested as a possible method of joining these components. The fundamental forces involved in optical contacting are reviewed and relates calculations of these forces to the results obtained in experiments.

  17. Systemic toxicity from repeated cutaneous contact with 2,4-pentanedione.

    PubMed

    Ballantyne, B

    2001-02-01

    2,4-Pentanedione (2,4 PD; CAS Number 123-54-6) is an industrial chemical with potential for skin contact. Repeated exposure studies by peroral and inhalation routes have shown central neurotoxicity and possible effects on the immune system. To determine the likelihood for systemic toxicity by cutaneous contact with 2,4-PD, a short-term repeated skin contact study was conducted in New Zealand white rabbits. The planned protocol was for dosing, with 0.5, 1.0 and 1.5 ml undiluted 2,4-PD by 6 h occlusive contact/d for 9 d; these were equivalent to dosages of 244, 975 and 1463 mg/kg/d. A dosage-related skin irritation was seen macroscopically and by light microscopy, which was minimal at the low dosage. Mortalities occurred at the mid (1/6 males, 3/6 females) and high dosages (5/12 males, 7/12 females), with deaths between the 2nd and 5th dosing day. In view of these mortalities and signs, dosing of the mid and high dose animals was discontinued, and survivors were kept to the end of the dosing period. Signs at the mid and high dosage included hypoactivity, tremors, convulsions, uncoordinated movements and prostration, and appeared between the 2nd and 4th dose. Body weight gain and food consumption were reduced for the mid and high dosage groups. Increased hemoglobin, hematocrit and erythrocyte counts may have been associated with dehydration, and increased heterophil count with cutaneous inflammation. Several serum biochemical changes reflected cutaneous irritation, and high creatine kinase activity was probably a consequence of convulsions. Immune effects included decreased lymphocyte counts and lymphoid necrosis in spleen and thymus. Central neuropathology in the mid and high dosages was seen as hemorrhages and neuronal degeneration, the latter principally in piriform cortex, globus pallidus and hippocampus. No peripheral neuropathy was present. 244 mg/kg/d was the no-effects dosage for systemic toxicity. This study confirmed a potential for systemic toxicity

  18. Impact of environmental conditions on the contact physics of gold contact RF microelectromechanical systems (MEMS) switches

    NASA Astrophysics Data System (ADS)

    Brown, Christopher John

    a function of time is related to the creep of gold asperities at the contact interface. The change in contact resistance over time can be described by a power law relation derived from the single asperity creep model that takes into account the surface topography, material characteristics, and contributions from additional sources such as adsorbed film layers. Additionally, it was shown that the creep mechanism was temperature dependent and that creep was significantly decreased at cryogenic temperatures. A drop in pressure as a result from cryogenic temperatures was observed to create switch bounce at closure. This was explored in a set of room temperature experiments which established the onset of bounce at 60 Torr. The results were and correlated to the damping coefficient and the ratio of the damping force to the electrostatic force of actuation. This work contributes to the field of contact physics and MEMS switch technology by firmly establishing the role of creep in contact mechanics and quantifying its time and temperature dependent impact on contact resistance.

  19. SORPTION PROPERTIES OF MODEL COMPOUNDS ON C18 ADSORBENTS

    EPA Science Inventory

    The bonded silica adsorbent Bondapak-C18 was evaluated for removing organic matter from secondary sewage effluents and from solutions of pure organic compounds. The adsorbent is hydrophobic and its behavior with water samples may be erratic unless first wet with a solvent. Howeve...

  20. Development of a Desulfurization Strategy for a NOx Adsorber Catalyst

    SciTech Connect

    Tomazic, Dean

    2000-08-20

    Improve NOx regeneration calibration developed in DECSE Phase I project to understand full potential of NOx adsorber catalyst over a range of operating temperatures. Develop and demonstrate a desulfurization process to restore NOx conversion efficiency lost to sulfur contamination. Investigate effect of desulfurization process on long-term performance of the NOx adsorber catalyst.

  1. The role of adsorbed water on the friction of a layer of submicron particles

    USGS Publications Warehouse

    Sammis, Charles G.; Lockner, David A.; Reches, Ze’ev

    2011-01-01

    Anomalously low values of friction observed in layers of submicron particles deformed in simple shear at high slip velocities are explained as the consequence of a one nanometer thick layer of water adsorbed on the particles. The observed transition from normal friction with an apparent coefficient near μ = 0.6 at low slip speeds to a coefficient near μ = 0.3 at higher slip speeds is attributed to competition between the time required to extrude the water layer from between neighboring particles in a force chain and the average lifetime of the chain. At low slip speeds the time required for extrusion is less than the average lifetime of a chain so the particles make contact and lock. As slip speed increases, the average lifetime of a chain decreases until it is less than the extrusion time and the particles in a force chain never come into direct contact. If the adsorbed water layer enables the otherwise rough particles to rotate, the coefficient of friction will drop to μ = 0.3, appropriate for rotating spheres. At the highest slip speeds particle temperatures rise above 100°C, the water layer vaporizes, the particles contact and lock, and the coefficient of friction rises to μ = 0.6. The observed onset of weakening at slip speeds near 0.001 m/s is consistent with the measured viscosity of a 1 nm thick layer of adsorbed water, with a minimum particle radius of approximately 20 nm, and with reasonable assumptions about the distribution of force chains guided by experimental observation. The reduction of friction and the range of velocities over which it occurs decrease with increasing normal stress, as predicted by the model. Moreover, the analysis predicts that this high-speed weakening mechanism should operate only for particles with radii smaller than approximately 1 μm. For larger particles the slip speed required for weakening is so large that frictional heating will evaporate the adsorbed water and weakening will not occur.

  2. The Impact of Adsorbed Triethylene Glycol on Water Wettability of the {1014} Calcium Carbonate Surface

    NASA Astrophysics Data System (ADS)

    Olsen, R.

    2015-12-01

    Water flooding is increasingly being used as a method of enhanced oil recovery and frequently involves calcium carbonate reservoirs. Very often, thermodynamic conditions in the upper few hundred meters allow for hydrate formation. One possible method of preventing hydrates is to inject hydrate inhibitors such as triethylene glycol (TEG) into the reservoir. Thus, it is of importance to know how such glycols affect water wettability, which is an important factor defining the oil behavior in such reservoirs. Wettability of a surface is defined by the contact angle of a liquid drop on the surface. The stronger the liquid is attracted to the surface, the smaller the wetting angle becomes, implying an increased degree of wetting. Therefore, it is possible to gain qualitative knowledge of the change in wetting properties with respect to external influences by studying corresponding changes in free energy of adsorption of the liquid. In our work [1], we used molecular dynamics (MD) and Born-Oppenheimer molecular dynamics (BOMD) to study how adsorbed TEG on the {1014} calcium carbonate surface affected adsorbed water. We used the changes in density profiles of water to estimate changes in adsorption free energy of water. The adaptive biasing force (ABF) method was applied to TEG to calculate the adsorption free energy of TEG on the calcium carbonate surface. We found that water wetting of the calcium carbonate surface decreased in the presence of adsorbed TEG. [1] - Olsen, R.; Leirvik, K.; Kvamme, B.; Kuznetsova, T. Adsorption Properties of Triethylene Glycol on a Hydrated {1014} Calcite Surface and Its Effect on Adsorbed Water, Langmuir 2015, DOI: 10.1021/acs.langmuir.5b02228

  3. Removing adsorbed heavy metal ions from sand surfaces via applying interfacial properties of rhamnolipid.

    PubMed

    Haryanto, Bode; Chang, Chien-Hsiang

    2015-01-01

    In this study, the interfacial properties of biosurfactant rhamnolipid were investigated and were applied to remove adsorbed heavy metal ions from sand surfaces with flushing operations. The surface tension-lowering activity, micelle charge characteristic, and foaming ability of rhamnolipid were identified first. For rhamnolipid in water, the negatively charged characteristic of micelles or aggregates was confirmed and the foaming ability at concentrations higher than 40 mg/L was evaluated. By using the rhamnolipid solutions in a batch washing approach, the potential of applying the interfacial properties of rhamnolipid to remove adsorbed copper ions from sand surfaces was then demonstrated. In rhamnolipid solution flushing operations for sand-packed medium, higher efficiency was found for the removal of adsorbed copper ions with residual type than with inner-sphere interaction type, implying the important role of interaction type between the copper ion and the sand surface in the removal efficiency. In addition, the channeling effect of rhamnolipid solution flow in the sand-packed medium was clearly observed in the solution flushing operations and was responsible for the low removal efficiency with low contact areas between solution and sand. By using rhamnolipid solution with foam to flush the sand-packed medium, one could find that the channeling effect of the solution flow was reduced and became less pronounced with the increase in the rhamnolipid concentration, or with the enhanced foaming ability. With the reduced channeling effect in the flushing operations, the removal efficiency for adsorbed copper ions was significantly improved. The results suggested that the foam-enhanced rhamnolipid solution flushing operation was efficient in terms of surfactant usage and operation time. PMID:25748376

  4. Dynamics of Confined Flexible and Unentangled Polymer Melts in Highly Adsorbing Cylindrical Pores

    SciTech Connect

    Carrillo, Jan-Michael Y; Sumpter, Bobby G

    2014-01-01

    Inspired by the recent neutron spin echo experiments (NSE) designed to address the dynamic phenomena in polymer melts that are induced by interactions with a confining surface, we performed coarse-grained molecular dynamics simulations to replicate the experimental results in order to provide new molecular insight for the observations. The results show excellent agreement in the values obtained for the normalized coherent single chain dynamic structure factor, S(Q;Dt)/S(Q;0) , between experiments and simulations. The simulations indicate that using different chain molecular weights that are used to achieve scattering contrast results in the uneven distribution of scatterers in the radial direction because lower molecular weight chains prefer to adsorb in the confining surface. In the bulk configuration, both simulations and experiments confirm that the polymer chains follow Rouse dynamics. However, under confinement, the Rouse modes are suppressed. The mean-squared radius of gyration, R2g, and the average relative shape anisotropy k2 of the conformation of the polymer chains indicate a pancake-like conformation near the surface and a bulk-like conformation near the center of the confining cylinder. Direct visualization of the polymers in the simulation confirm the pancake-like conformation of the adsorbed chains and the presence of trains, loops and tails in the region between the adsorbed chains and the chains not in contact with the surface. Despite the presence of these different conformations, the average form factor of the confined chains still follows the Debye function which describes linear ideal chains, which is in agreement with small angle neutron scattering (SANS) experiments. The experimentally inaccessible mean squared displacement of the confined monomers, calculated as a function of radial distance from the pore surface, was obtained in the simulations. The simulation shows a gradual increase of the MSD from the adsorbed, but mobile layer, to that

  5. Occupational Contact Dermatitis

    PubMed Central

    2008-01-01

    Occupational contact dermatitis accounts for 90% of all cases of work-related cutaneous disorders. It can be divided into irritant contact dermatitis, which occurs in 80% of cases, and allergic contact dermatitis. In most cases, both types will present as eczematous lesions on exposed parts of the body, notably the hands. Accurate diagnosis relies on meticulous history taking, thorough physical examination, careful reading of Material Safety Data Sheets to distinguish between irritants and allergens, and comprehensive patch testing to confirm or rule out allergic sensitization. This article reviews the pathogenesis and clinical manifestations of occupational contact dermatitis and provides diagnostic guidelines and a rational approach to management of these often frustrating cases. PMID:20525126

  6. Contacting American Overseas Schools.

    ERIC Educational Resources Information Center

    Engelhardt, David

    1993-01-01

    Provides contacts for architects or educational consultants who wish to work overseas. Cites a directory, newsletters, newspapers, and associations focused on educators involved with independent overseas schools that are organized around the United States curriculum. (MLF)

  7. ELECTRIC CONTACT MEANS

    DOEpatents

    Grear, J.W. Jr.

    1959-03-10

    A switch adapted to maintain electrical connections under conditions of vibration or acceleration is described. According to the invention, thc switch includes a rotatable arm carrying a conductive bar arranged to close against two contacts spaced in the same plane. The firm and continuous engagement of the conductive bar with the contacts is acheived by utilizeing a spring located betwenn the vbar and athe a rem frzme and slidable mounting the bar in channel between two arms suspendef from the arm frame.

  8. The impact of contact

    NASA Astrophysics Data System (ADS)

    Finney, B.

    1986-10-01

    Scenarios of the impact on human society of radio contact with an extraterrestrial civilization are presented. Some believe that contact with advanced extraterrestrials would quickly devastate the human spirit, while others believe that these super-intelligent beings would show the inhabitants of the earth how to live in peace. It is proposed that the possible existence of extraterrestrial civilizations and the development of means of studying and communicating with them need to be considered.

  9. Contact dermatitis complicating pinnaplasty.

    PubMed

    Singh-Ranger, G; Britto, J A; Sommerlad, B C

    2001-04-01

    Proflavine allergy is uncommon, occurring in approximately 6% of patients attending contact dermatitis clinics. Proflavine wool is used by many surgeons in the UK as a dressing that can be moulded to conform to the contours of a corrected prominent ear. It may have bacteriostatic properties. We present a case where contact dermatitis in response to proflavine developed after pinnaplasty. This caused diagnostic confusion, a lengthened hospital stay and an unsightly hypertrophic scar. PMID:11254419

  10. Kinetic study of lead adsorption to composite biopolymer adsorbent

    SciTech Connect

    Seki, H.; Suzuki, A.

    1999-03-15

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

  11. Structure and properties of water film adsorbed on mica surfaces

    NASA Astrophysics Data System (ADS)

    Zhao, Gutian; Tan, Qiyan; Xiang, Li; Cai, Di; Zeng, Hongbo; Yi, Hong; Ni, Zhonghua; Chen, Yunfei

    2015-09-01

    The structure profiles and physical properties of the adsorbed water film on a mica surface under conditions with different degrees of relative humidity are investigated by a surface force apparatus. The first layer of the adsorbed water film shows ice-like properties, including a lattice constant similar with ice crystal, a high bearing capacity that can support normal pressure as high as 4 MPa, a creep behavior under the action of even a small normal load, and a character of hydrogen bond. Adjacent to the first layer of the adsorbed water film, the water molecules in the outer layer are liquid-like that can flow freely under the action of external loads. Experimental results demonstrate that the adsorbed water layer makes the mica surface change from hydrophilic to weak hydrophobic. The weak hydrophobic surface may induce the latter adsorbed water molecules to form water islands on a mica sheet.

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

    PubMed

    Seki; Suzuki

    1999-03-15

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

  13. Lettuce contact allergy.

    PubMed

    Paulsen, Evy; Andersen, Klaus E

    2016-02-01

    Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present new data on lettuce contact allergy and review the literature. Lettuce is weakly allergenic, and occupational cases are mainly reported. Using aimed patch testing in Compositae-allergic patients, two recent Danish studies showed prevalence rates of positive lettuce reactions of 11% and 22%. The majority of cases are non-occupational, and may partly be caused by cross-reactivity. The sesquiterpene lactone mix seems to be a poor screening agent for lettuce contact allergy, as the prevalence of positive reactions is significantly higher in non-occupationally sensitized patients. Because of the easy degradability of lettuce allergens, it is recommended to patch test with freshly cut lettuce stem and supplement this with Compositae mix. As contact urticaria and protein contact dermatitis may present as dermatitis, it is important to perform prick-to-prick tests, and possibly scratch patch tests as well. Any person who is occupationally exposed to lettuce for longer periods, especially atopics, amateur gardeners, and persons keeping lettuce-eating pets, is potentially at risk of developing lettuce contact allergy. PMID:26289653

  14. Feasability of a new process to produce fast disintegrating pellets as novel multiparticulate dosage form for pediatric use.

    PubMed

    Hoang Thi, Thanh Huong; Lhafidi, Siham; Carneiro, Simone Pinto; Flament, Marie-Pierre

    2015-12-30

    Novel orally disintegrating system based on multiparticulate form was developed, offering an alternative to encounter major issues in the design of dosage form for pediatric patients, i.e., the difficulty in swallowing large solid dosage form (tablet or capsule), and the requirement to cover a broad range of doses for different age groups. Microcrystalline cellulose-based pellets containing acetaminophen were prepared via extrusion/spheronization followed by freeze-drying. The in vitro disintegration behavior of these pellets was quantitatively measured with a texture analyzer. Mercury intrusion and gas adsorption techniques, scanning electron microscopy of pellet surface and cross-section were performed in order to characterize their internal porous structure. Pellets characteristics such as size distribution, sphericity, friability and drug release were also determined. The developing process was able to produce pellets containing high drug loading (25, 50 and up to 75%, w/w) with good sphericity (aspect ratio ∼1) and low friability. The pellets exhibited an instantaneous disintegration upon contact with water, which was indicated by two parameters: the disintegration onset was approximating to 0, and the disintegration time less than 5s. The fast disintegration behavior is correlated with the pellet internal structure characterized by a capillary network with pore diameter varying from 0.1 to 10μm. Such a structure not only ensured a rapid disintegration but it also offers to freeze-dried pellets adequate mechanical properties in comparison with conventional freeze-dried forms. Due to pellet disintegration, fast dissolution of acetaminophen was achieved, i.e., more than 90% of drug released within 15min. This novel multiparticulate system offers novel age-appropriate dosage form for pediatric population owing to their facility of administration (fast disintegration) and dosing flexibility (divided and reduced-size solid form). PMID:26403385

  15. Long-acting injectable hormonal dosage forms for contraception.

    PubMed

    Wu, Linfeng; Janagam, Dileep R; Mandrell, Timothy D; Johnson, James R; Lowe, Tao L

    2015-07-01

    Although great efforts have been made to develop long-acting injectable hormonal contraceptives for more than four decades, few long-acting injectable contraceptives have reached the pharmaceutical market or even entered clinical trials. On the other hand, in clinical practice there is an urgent need for injectable long-acting reversible contraceptives which can provide contraceptive protection for more than 3 months after one single injection. Availability of such products will offer great flexibility to women and resolve certain continuation issues currently occurring in clinics. Herein, we reviewed the strategies exploited in the past to develop injectable hormonal contraceptive dosages including drug microcrystal suspensions, drug-loaded microsphere suspensions and in situ forming depot systems for long-term contraception and discussed the potential solutions for remaining issues met in the previous development. PMID:25899076

  16. Mammalian Y chromosomes retain widely expressed dosage-sensitive regulators.

    PubMed

    Bellott, Daniel W; Hughes, Jennifer F; Skaletsky, Helen; Brown, Laura G; Pyntikova, Tatyana; Cho, Ting-Jan; Koutseva, Natalia; Zaghlul, Sara; Graves, Tina; Rock, Susie; Kremitzki, Colin; Fulton, Robert S; Dugan, Shannon; Ding, Yan; Morton, Donna; Khan, Ziad; Lewis, Lora; Buhay, Christian; Wang, Qiaoyan; Watt, Jennifer; Holder, Michael; Lee, Sandy; Nazareth, Lynne; Alföldi, Jessica; Rozen, Steve; Muzny, Donna M; Warren, Wesley C; Gibbs, Richard A; Wilson, Richard K; Page, David C

    2014-04-24

    The human X and Y chromosomes evolved from an ordinary pair of autosomes, but millions of years ago genetic decay ravaged the Y chromosome, and only three per cent of its ancestral genes survived. We reconstructed the evolution of the Y chromosome across eight mammals to identify biases in gene content and the selective pressures that preserved the surviving ancestral genes. Our findings indicate that survival was nonrandom, and in two cases, convergent across placental and marsupial mammals. We conclude that the gene content of the Y chromosome became specialized through selection to maintain the ancestral dosage of homologous X-Y gene pairs that function as broadly expressed regulators of transcription, translation and protein stability. We propose that beyond its roles in testis determination and spermatogenesis, the Y chromosome is essential for male viability, and has unappreciated roles in Turner's syndrome and in phenotypic differences between the sexes in health and disease. PMID:24759411

  17. Drug dosage in continuous venoveno hemofiltration in critically ill children.

    PubMed

    Assadi, Farahnak; Shahrbaf, Fatemeh Ghane

    2016-01-01

    The dosage of drugs in patients requiring continuous renal replacement therapy need to be adjusted based on a number of variables that that affect pharmacokinetics (PK) including patient weight, CRRT modality (convention, vs. diffusion), blood and/or effluent flow, hemofilter characteristics, physiochemical drug properties, volume of distribution, protein binding and half-life as well as residual renal function. There is a paucity of data on PK studies in children with acute kidney injury requiring CRRT. When possible, therapeutic drug monitoring should be utilized for those medications where serum drug concentrations can be obtained in a clinically relevant time frame. Also, a patient-centered team approach that includes an intensive care unit pharmacist is recommended to prevent medication-related errors and enhance safe and effective medication use is highly recommended. The aim of this article is to review the current guidelines for drug dosing in critically ill children who require continuous venovenous hemofiltration. PMID:26709896

  18. Mammalian Y chromosomes retain widely expressed dosage-sensitive regulators

    PubMed Central

    Bellott, Daniel W.; Hughes, Jennifer F.; Skaletsky, Helen; Brown, Laura G.; Pyntikova, Tatyana; Cho, Ting-Jan; Koutseva, Natalia; Zaghlul, Sara; Graves, Tina; Rock, Susie; Kremitzki, Colin; Fulton, Robert S.; Dugan, Shannon; Ding, Yan; Morton, Donna; Khan, Ziad; Lewis, Lora; Buhay, Christian; Wang, Qiaoyan; Watt, Jennifer; Holder, Michael; Lee, Sandy; Nazareth, Lynne; Alföldi, Jessica; Rozen, Steve; Muzny, Donna M.; Warren, Wesley C.; Gibbs, Richard A.; Wilson, Richard K.; Page, David C.

    2014-01-01

    The human X and Y chromosomes evolved from an ordinary pair of autosomes, but millions of years ago genetic decay ravaged the Y chromosome, and only three percent of its ancestral genes survived. We reconstructed the evolution of the Y chromosome across eight mammals to identify biases in gene content and the selective pressures that preserved the surviving ancestral genes. Our findings indicate that survival was non-random, and in two cases, convergent across placental and marsupial mammals. We conclude that the Y chromosome's gene content became specialized through selection to maintain the ancestral dosage of homologous X-Y gene pairs that function as broadly expressed regulators of transcription, translation and protein stability. We propose that beyond its roles in testis determination and spermatogenesis, the Y chromosome is essential for male viability, and plays unappreciated roles in Turner syndrome and in phenotypic differences between the sexes in health and disease. PMID:24759411

  19. Oral Solid Dosage Form Disintegration Testing - The Forgotten Test.

    PubMed

    Al-Gousous, Jozef; Langguth, Peter

    2015-09-01

    Since its inception in the 1930s, disintegration testing has become an important quality control (QC) test in pharmaceutical industry, and disintegration test procedures for various dosage forms have been described by the different pharmacopoeias, with harmonization among them still not quite complete. However, because of the fact that complete disintegration does not necessarily imply complete dissolution, much more research has been focused on dissolution rather than on disintegration testing. Nevertheless, owing to its simplicity, disintegration testing seems to be an attractive replacement to dissolution testing as recognized by the International Conference on Harmonization guidelines, in some cases. Therefore, with proper research being carried out to overcome the associated challenges, the full potential of disintegration testing could be tapped saving considerable efforts allocated to QC testing and quality assurance. PMID:25546430

  20. Milestone Report - Complete New Adsorbent Materials for Marine Testing to Demonstrate 4.5 g-U/kg Adsorbent

    SciTech Connect

    Janke, Christopher James; Das, Sadananda; Oyola, Yatsandra; Mayes, Richard T.; Saito, Tomonori; Brown, Suree; Gill, Gary; Kuo, Li-Jung; Wood, Jordana

    2014-08-01

    This report describes work on the successful completion of Milestone M2FT-14OR03100115 (8/20/2014) entitled, “Complete new adsorbent materials for marine testing to demonstrate 4.5 g-U/kg adsorbent”. This effort is part of the Seawater Uranium Recovery Program, sponsored by the U.S. Department of Energy, Office of Nuclear Energy, and involved the development of new adsorbent materials at the Oak Ridge National Laboratory (ORNL) and marine testing at the Pacific Northwest National Laboratory (PNNL). ORNL has recently developed two new families of fiber adsorbents that have demonstrated uranium adsorption capacities greater than 4.5 g-U/kg adsorbent after marine testing at PNNL. One adsorbent was synthesized by radiation-induced graft polymerization of itaconic acid and acrylonitrile onto high surface area polyethylene fibers followed by amidoximation and base conditioning. This fiber showed a capacity of 4.6 g-U/kg adsorbent in marine testing at PNNL. The second adsorbent was prepared by atom-transfer radical polymerization of t-butyl acrylate and acrylonitrile onto halide-functionalized round fibers followed by amidoximation and base hydrolysis. This fiber demonstrated uranium adsorption capacity of 5.4 g-U/kg adsorbent in marine testing at PNNL.

  1. Over-the-counter pharmaceuticals: exploratory research of consumer preference toward solid oral dosage forms.

    PubMed

    Reisenwitz, T H; Wimbish, G J

    1996-01-01

    The capsule dosage form in nonprescription pharmaceuticals persists as being one of the most vulnerable to product tampering. This study examines consumer preference toward three solid oral dosage forms (capsules, caplets, and tablets) in nonprescription products. Thirteen independent variables representing dosage form attributes are measured on semantic differential scales. The data are analyzed using analysis of variance (ANOVA) and factor analysis. Implications for the pharmaceutical marketer are noted. Future directions for research are also outlined. PMID:10159645

  2. Imaging the wave functions of adsorbed molecules

    PubMed Central

    Lüftner, Daniel; Ules, Thomas; Reinisch, Eva Maria; Koller, Georg; Soubatch, Serguei; Tautz, F. Stefan; Ramsey, Michael G.; Puschnig, Peter

    2014-01-01

    The basis for a quantum-mechanical description of matter is electron wave functions. For atoms and molecules, their spatial distributions and phases are known as orbitals. Although orbitals are very powerful concepts, experimentally only the electron densities and -energy levels are directly observable. Regardless whether orbitals are observed in real space with scanning probe experiments, or in reciprocal space by photoemission, the phase information of the orbital is lost. Here, we show that the experimental momentum maps of angle-resolved photoemission from molecular orbitals can be transformed to real-space orbitals via an iterative procedure which also retrieves the lost phase information. This is demonstrated with images obtained of a number of orbitals of the molecules pentacene (C22H14) and perylene-3,4,9,10-tetracarboxylic dianhydride (C24H8O6), adsorbed on silver, which are in excellent agreement with ab initio calculations. The procedure requires no a priori knowledge of the orbitals and is shown to be simple and robust. PMID:24344291

  3. Mesoporous carbon nanomaterials as environmental adsorbents.

    PubMed

    Tripathi, Pranav K; Gan, Lihua; Liu, Mingxian; Rao, Nageswara N

    2014-02-01

    The transportation and diffusion of the guest objects or molecules in the porous carbon nanomaterials can be facilitated by reducing the pathway and resistance. The reduced pathway depends on the porous nature of carbon nanomaterials. Classification of porous carbon materials by the International Union of Pure and Applied Chemistry (IUPAC) has given a new opportunity to design the pores as per their applicability and to understand the mobility of ions, atoms, and molecules in the porous network of carbon materials and also advanced their countless applicability. However, synthesis of carbon nanomaterials with a desired porous network is still a great challenge. Although, remarkable developments have taken place in the recent years, control over the pores size and/or hierarchical porous architectures, especially in the synthesis of carbon nanospheres (CNSs) and ordered mesoporous carbon (OMCs) is still intriguing. The micro and mesoporous CNSs and OMCs have been prepared by a variety of procedures and over a wide range of compositions using various different surfactant templates and carbon precursors etc. The mechanisms of formation of micromesopore in the CNSs and OMCs are still evolving. On the other hand, the urge for adsorbents with very high adsorption capacities for removing contaminants from water is growing steadily. In this review, we address the state-of-the-art synthesis of micro and mesoporous CNSs and OMCs, giving examples of their applications for adsorptive removals of contaminants including our own research studies. PMID:24749459

  4. NASA Applications of Molecular Adsorber Coatings

    NASA Technical Reports Server (NTRS)

    Abraham, Nithin S.

    2015-01-01

    The Molecular Adsorber Coating (MAC) is a new, innovative technology that was developed to reduce the risk of molecular contamination on spaceflight applications. Outgassing from materials, such as plastics, adhesives, lubricants, silicones, epoxies, and potting compounds, pose a significant threat to the spacecraft and the lifetime of missions. As a coating made of highly porous inorganic materials, MAC offers impressive adsorptive capabilities that help capture and trap contaminants. Past research efforts have demonstrated the coating's promising adhesion performance, optical properties, acoustic durability, and thermal stability. These results advocate its use near or on surfaces that are targeted by outgassed materials, such as internal optics, electronics, detectors, baffles, sensitive instruments, thermal control coatings, and vacuum chamber test environments. The MAC technology has significantly progressed in development over the recent years. This presentation summarizes the many NASA spaceflight applications of MAC and how the coatings technology has been integrated as a mitigation tool for outgassed contaminants. For example, this sprayable paint technology has been beneficial for use in various vacuum chambers for contamination control and hardware bake-outs. The coating has also been used in small instrument cavities within spaceflight instrument for NASA missions.

  5. Morphological characterization of furfuraldehyde resins adsorbents

    SciTech Connect

    Sanchez, R.; Monteiro, S.N.; D`Almeida, J.R.

    1996-12-31

    Sugar cane is one of the most traditional plantation cultivated crops in large areas in Brazil. The State University of the North of Rio de Janeiro, UENF, is currently engaged in a program aimed to exploit the potentialities of sugar cane industry as a self sustained non-polluting enterprise. One of the projects being carried out at the UENF is the transformation of sugar cane bagasse in precursor materials for the industry of furan derivatives such as the furfuraldehyde resins obtained by acid catalysis. The possibility of employing acid catalyzed furfuraldehyde resins as selective adsorbents has arisen during a comprehensive study of physical-chemical adsorption properties of these materials. The morphology of these resins depend on the synthesis method. Scanning Electron Microscopic studies of these materials which were synthesized, in bulk (FH-M) and solution (FH-D), showed differences in surface density and particle size. Using mercury porosimeter techniques and BET adsorption methods, it was found different pore size distributions and a decrement in surface area when solvent was employed in the synthesis process. By thermogravimetric analysis it was found similar weight losses (6%) of water adsorption and a small differences in thermal stabilities.

  6. Compensation of Dosage-Sensitive Genes on the Chicken Z Chromosome.

    PubMed

    Zimmer, Fabian; Harrison, Peter W; Dessimoz, Christophe; Mank, Judith E

    2016-01-01

    In many diploid species, sex determination is linked to a pair of sex chromosomes that evolved from a pair of autosomes. In these organisms, the degeneration of the sex-limited Y or W chromosome causes a reduction in gene dose in the heterogametic sex for X- or Z-linked genes. Variations in gene dose are detrimental for large chromosomal regions when they span dosage-sensitive genes, and many organisms were thought to evolve complete mechanisms of dosage compensation to mitigate this. However, the recent realization that a wide variety of organisms lack complete mechanisms of sex chromosome dosage compensation has presented a perplexing question: How do organisms with incomplete dosage compensation avoid deleterious effects of gene dose differences between the sexes? Here we use expression data from the chicken (Gallus gallus) to show that ohnologs, duplicated genes known to be dosage-sensitive, are preferentially dosage-compensated on the chicken Z chromosome. Our results indicate that even in the absence of a complete and chromosome wide dosage compensation mechanism, dosage-sensitive genes are effectively dosage compensated on the Z chromosome. PMID:27044516

  7. Compensation of Dosage-Sensitive Genes on the Chicken Z Chromosome

    PubMed Central

    Zimmer, Fabian; Harrison, Peter W.; Dessimoz, Christophe; Mank, Judith E.

    2016-01-01

    In many diploid species, sex determination is linked to a pair of sex chromosomes that evolved from a pair of autosomes. In these organisms, the degeneration of the sex-limited Y or W chromosome causes a reduction in gene dose in the heterogametic sex for X- or Z-linked genes. Variations in gene dose are detrimental for large chromosomal regions when they span dosage-sensitive genes, and many organisms were thought to evolve complete mechanisms of dosage compensation to mitigate this. However, the recent realization that a wide variety of organisms lack complete mechanisms of sex chromosome dosage compensation has presented a perplexing question: How do organisms with incomplete dosage compensation avoid deleterious effects of gene dose differences between the sexes? Here we use expression data from the chicken (Gallus gallus) to show that ohnologs, duplicated genes known to be dosage-sensitive, are preferentially dosage-compensated on the chicken Z chromosome. Our results indicate that even in the absence of a complete and chromosome wide dosage compensation mechanism, dosage-sensitive genes are effectively dosage compensated on the Z chromosome. PMID:27044516

  8. Contact Lenses for Vision Correction

    MedlinePlus

    ... Contact Lenses Colored Contact Lenses Contact Lenses for Vision Correction Written by: Kierstan Boyd Reviewed by: Brenda ... on the surface of the eye. They correct vision like eyeglasses do and are safe when used ...

  9. From adsorption to condensation: the role of adsorbed molecular clusters.

    PubMed

    Yaghoubian, Sima; Zandavi, Seyed Hadi; Ward, C A

    2016-08-01

    The adsorption of heptane vapour on a smooth silicon substrate with a lower temperature than the vapour is examined analytically and experimentally. An expression for the amount adsorbed under steady state conditions is derived from the molecular cluster model of the adsorbate that is similar to the one used to derive the equilibrium Zeta adsorption isotherm. The amount adsorbed in each of a series of steady experiments is measured using a UV-vis interferometer, and gives strong support to the amount predicted to be adsorbed. The cluster distribution is used to predict the subcooling temperature required for the adsorbed vapour to make a disorder-order phase transition to become an adsorbed liquid, and the subcooling temperature is found to be 2.7 ± 0.4 K. The continuum approach for predicting the thickness of the adsorbed liquid film originally developed by Nusselt is compared with that measured and is found to over-predict the thickness by three-orders of magnitude. PMID:27426944

  10. Methane Recovery from Gaseous Mixtures Using Carbonaceous Adsorbents

    NASA Astrophysics Data System (ADS)

    Buczek, Bronisław

    2016-06-01

    Methane recovery from gaseous mixtures has both economical and ecological aspect. Methane from different waste gases like mine gases, nitrogenated natural gases and biogases can be treated as local source for production electric and heat energy. Also occurs the problem of atmosphere pollution with methane that shows over 20 times more harmful environmental effect in comparison to carbon dioxide. One of the ways utilisation such gases is enrichment of methane in the PSA technique, which requires appropriate adsorbents. Active carbons and carbon molecular sieve produced by industry and obtained in laboratory scale were examined as adsorbent for methane recuperation. Porous structure of adsorbents was investigated using densimetry measurements and adsorption of argon at 77.5K. On the basis of adsorption data, the Dubinin-Radushkevich equation parameters, micropore volume (Wo) and characteristics of energy adsorption (Eo) as well as area micropores (Smi) and BET area (SBET) were determined. The usability of adsorbents in enrichment of the methane was evaluated in the test, which simulate the basic stages of PSA process: a) adsorbent degassing, b) pressure raise in column by feed gas, c) cocurrent desorption with analysis of out flowing gas. The composition of gas phase was accepted as the criterion of the suitability of adsorbent for methane separation from gaseous mixtures. The relationship between methane recovery from gas mixture and texture parameters of adsorbents was found.

  11. Mercury adsorption properties of sulfur-impregnated adsorbents

    USGS Publications Warehouse

    Hsi, N.-C.; Rood, M.J.; Rostam-Abadi, M.; Chen, S.; Chang, R.

    2002-01-01

    Carbonaceous and noncarbonaceous adsorbents were impregnated with elemental sulfur to evaluate the chemical and physical properties of the adsorbents and their equilibrium mercury adsorption capacities. Simulated coal combustion flue gas conditions were used to determine the equilibrium adsorption capacities for Hg0 and HgCl2 gases to better understand how to remove mercury from gas streams generated by coal-fired utility power plants. Sulfur was deposited onto the adsorbents by monolayer surface deposition or volume pore filling. Sulfur impregnation increased the total sulfur content and decreased the total and micropore surface areas and pore volumes for all of the adsorbents tested. Adsorbents with sufficient amounts of active adsorption sites and sufficient microporous structure had mercury adsorption capacities up to 4,509 ??g Hg/g adsorbent. Elemental sulfur, organic sulfur, and sulfate were formed on the adsorbents during sulfur impregnation. Correlations were established with R2>0.92 between the equilibrium Hg0/HgCl2 adsorption capacities and the mass concentrations of elemental and organic sulfur. This result indicates that elemental and organic sulfur are important active adsorption sites for Hg0 and HgCl2.

  12. Contact-active antibacterial aerogels from cellulose nanofibrils.

    PubMed

    Henschen, Jonatan; Illergård, Josefin; Larsson, Per A; Ek, Monica; Wågberg, Lars

    2016-10-01

    The use of cellulose aerogels as antibacterial materials has been investigated by applying a contact-active layer-by-layer modification to the aerogel surface. Studying the adsorption of multilayers of polyvinylamine (PVAm) and polyacrylic acid to aerogels comprising crosslinked cellulose nanofibrils and monitoring the subsequent bacterial adhesion revealed that up to 26mgPVAmgaerogel(-1) was adsorbed without noticeably affecting the aerogel structure. The antibacterial effect was tested by measuring the reduction of viable bacteria in solution when the aerogels were present. The results show that >99.9% of the bacteria adhered to the surface of the aerogels. Microscopy further showed adherence of bacteria to the surfaces of the modified aerogels. These results indicate that it is possible to create materials with three-dimensional cellulose structures that adsorb bacteria with very high efficiency utilizing the high specific surface area of the aerogels in combination with their open structure. PMID:27391038

  13. Contact binary stars

    NASA Astrophysics Data System (ADS)

    Mochnacki, S. W.

    1981-04-01

    Densities, corrected primary colors, minimum periods, inferred masses, luminosities, and specific angular momenta are computed from data on 37 W Ursae Majoris systems. A-type systems, having lower densities and angular momenta than the W-type systems, are shown to be evolved, and a new class of contact binary is identified, the OO Aquilae systems, whose members have evolved into contact. Evolutionary grids based on the contact condition agree with observation, except in that the evolved A-type systems have lost more angular momentum than predicted by gravitational radiation alone. This is accounted for by stellar wind magnetic braking, which is shown to be effective on a shorter time scale and to be important in other kinds of binaries containing a cool, tidally coupled component.

  14. Shoe allergic contact dermatitis.

    PubMed

    Matthys, Erin; Zahir, Amir; Ehrlich, Alison

    2014-01-01

    Foot dermatitis is a widespread condition, affecting men and women of all ages. Because of the location, this condition may present as a debilitating problem to those who have it. Allergic contact dermatitis involving the feet is frequently due to shoes or socks. The allergens that cause shoe dermatitis can be found in any constituent of footwear, including rubber, adhesives, leather, dyes, metals, and medicaments. The goal of treatment is to identify and minimize contact with the offending allergen(s). The lack of product information released from shoe manufacturers and the continually changing trends in footwear present a challenge in treating this condition. The aim of this study is to review the current literature on allergic contact shoe dermatitis; clinical presentation, allergens, patch testing, and management will be discussed. PubMed and MEDLINE databases were used for the search, with a focus on literature updates from the last 15 years. PMID:25000234

  15. Contact sensitization in children.

    PubMed

    Manzini, B M; Ferdani, G; Simonetti, V; Donini, M; Seidenari, S

    1998-01-01

    Our study concerns contact sensitization in children, the frequency of which is still debated in the literature, even though specific reports are increasing. During a 7 year period (1988-1994) 670 patients, 6 months to 12 years of age, were patch tested with the European standard series, integrated with 24 haptens, at the same concentrations as for adults. We observed positive results in 42% of our patients. Thimerosal, nickel sulfate, Kathon CG, fragrance mix, neomycin, wool alcohols, and ammoniated mercury induced most of the positive responses. The highest sensitization rate was found in children from 0 to 3 years of age. Comments on main positive haptens are reported. Seventy-seven percent of our sensitized patients were atopics, suggesting that atopy represents a predisposing factor for contact hypersensitivity. Patch testing represents a useful diagnostic procedure for the definition of childhood eczematous dermatitis and for the identification of agents inducing contact sensitization which is frequently associated with atopic dermatitis. PMID:9496796

  16. Cross-contact chain

    NASA Technical Reports Server (NTRS)

    Lieneweg, Udo (Inventor)

    1988-01-01

    A system is provided for use with wafers that include multiple integrated circuits that include two conductive layers in contact at multiple interfaces. Contact chains are formed beside the integrated circuits, each contact chain formed of the same two layers as the circuits, in the form of conductive segments alternating between the upper and lower layers and with the ends of the segments connected in series through interfaces. A current source passes a current through the series-connected segments, by way of a pair of current tabs connected to opposite ends of the series of segments. While the current flows, voltage measurements are taken between each of a plurality of pairs of voltage tabs, the two tabs of each pair connected to opposite ends of an interface that lies along the series-connected segments. A plot of interface conductances on a normal probability chart, enables prediction of the yield of good integrated circuits from the wafer.

  17. Cross-contact chain

    NASA Technical Reports Server (NTRS)

    Lieneweg, U. (Inventor)

    1986-01-01

    A system is provided for use with wafers that include multiple integrated circuits that include two conductive layers in contact at multiple interfaces. Contact chains are formed beside the integrated circuits, each contact chain formed of the same two layers as the circuits, in the form of conductive segments alternating between the upper and lower layers and with the ends of the segments connected in series through interfaces. A current source passes a current through the series-connected segments, by way of a pair of current tabs connected to opposite ends of the series of segments. While the current flows, voltage measurements are taken between each of a plurality of pairs of voltage tabs, the two tabs of each pair connected to opposite ends of an interface that lies along the series-connected segments. A plot of interface conductances on normal probability chart enables prediction of the yield of good integrated circuits from the wafer.

  18. Remediation of Organic and Inorganic Arsenic Contaminated Groundwater using a Nonocrystalline TiO2 Based Adsorbent

    SciTech Connect

    Jing, C.; Meng, X; Calvache, E; Jiang, G

    2009-01-01

    A nanocrystalline TiO2-based adsorbent was evaluated for the simultaneous removal of As(V), As(III), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in contaminated groundwater. Batch experimental results show that As adsorption followed pseudo-second order rate kinetics. The competitive adsorption was described with the charge distribution multi-site surface complexation model (CD-MUSIC). The groundwater containing an average of 329 ?g L-1 As(III), 246 ?g L-1 As(V), 151 ?g L-1 MMA, and 202 ?g L-1 DMA was continuously passed through a TiO2 filter at an empty bed contact time of 6 min for 4 months. Approximately 11 000, 14 000, and 9900 bed volumes of water had been treated before the As(III), As(V), and MMA concentration in the effluent increased to 10 ?g L-1. However, very little DMA was removed. The EXAFS results demonstrate the existence of a bidentate binuclear As(V) surface complex on spent adsorbent, indicating the oxidation of adsorbed As(III). A nanocrystalline TiO2-based adsorbent could be used for the simultaneous removal of As(V), As(III), MMA, and DMA in contaminated groundwater.

  19. A modified cryostat for photo-electrical characterization of porous materials in controlled atmosphere at very low gas dosage

    NASA Astrophysics Data System (ADS)

    Cultrera, Alessandro; Amato, Giampiero; Boarino, Luca; Lamberti, Carlo

    2014-08-01

    We developed an integrated system for photo-electrical characterization of materials for sensing applications in strictly controlled environment conditions. The peculiar aspect of this setup is the capability of a fine-tuned gas dosage and a fast dynamic chamber pressure control, coupled with current and voltage sensing within a modified cryostat. To illustrate the capabilities of our system we have characterised both p+-type mesoporous silicon (meso-PS) membranes and nano-crystalline mesoporous titanium dioxide (nc-TiO2) films. In particular, as a main topic is presented a well-resolved characterization of mesoporous silicon electrical conductivity changes induced by presence of ethanol. At low pore filling level adsorbate-shunted conduction is avoided, while dielectric screening effects on frozen doping centres are observable. Beside we presented observation of mesoporous titanium dioxide photo-conductivity as a function of different gas pressure reporting opposite effects of relatively low- and high-pressure regimes. High reproducibility provided by the system is discussed as a final remark.

  20. Alkylammonium montmorillonites as adsorbents for organic vapors from air

    SciTech Connect

    Harper, M.; Purnell, C.J. )

    1990-01-01

    Montmorillonite clays may be modified by the exchange of the inorganic interlayer cations with alkylammonium ions, resulting in a fixed internal porosity. The pore size and shape depend on the nature of the alkylammonium ion. A number of different ions were used to prepare adsorbents with varying properties, and these were examined for their potential application to sampling organic vapors in air. Characterization involved determination of nitrogen and water contents, surface area, interlayer spacing, thermal stability, and breakthrough volumes of organic vapors. The adsorbent that showed the most promise (tetramethylammonium montmorillonite (TMA)) was further evaluated for use as an adsorbent in both thermal- and solvent-desorable sampling systems.

  1. Dosage optimization in positron emission tomography: state-of-the-art methods and future prospects

    PubMed Central

    Karakatsanis, Nicolas A; Fokou, Eleni; Tsoumpas, Charalampos

    2015-01-01

    Positron emission tomography (PET) is widely used nowadays for tumor staging and therapy response in the clinic. However, average PET radiation exposure has increased due to higher PET utilization. This study aims to review state-of-the-art PET tracer dosage optimization methods after accounting for the effects of human body attenuation and scan protocol parameters on the counting rate. In particular, the relationship between the noise equivalent count rate (NECR) and the dosage (NECR-dosage curve) for a range of clinical PET systems and body attenuation sizes will be systematically studied to prospectively estimate the minimum dosage required for sufficiently high NECR. The optimization criterion can be determined either as a function of the peak of the NECR-dosage curve or as a fixed NECR score when NECR uniformity across a patient population is important. In addition, the systematic NECR assessments within a controllable environment of realistic simulations and phantom experiments can lead to a NECR-dosage response model, capable of predicting the optimal dosage for every individual PET scan. Unlike conventional guidelines suggesting considerably large dosage levels for obese patients, NECR-based optimization recommends: i) moderate dosage to achieve 90% of peak NECR for obese patients, ii) considerable dosage reduction for slimmer patients such that uniform NECR is attained across the patient population, and iii) prolongation of scans for PET/MR protocols, where longer PET acquisitions are affordable due to lengthy MR sequences, with motion compensation becoming important then. Finally, the need for continuous adaptation of dosage optimization to emerging technologies will be discussed. PMID:26550543

  2. Contact activation of blood-plasma coagulation

    NASA Astrophysics Data System (ADS)

    Golas, Avantika

    "adsorption-dilution" effect that blocks FXII contact with hydrophobic activator surfaces. The adsorption-dilution effect explains the apparent specificity for hydrophilic activators pursued by earlier investigators. Finally a comparison of FXII autoactivation in buffer, serum, protein cocktail, and plasma solutions is shown herein. Activation of blood plasma coagulation in vitro by contact with material surfaces is demonstrably dependent on plasma-volume-to-activator-surface-area ratio. However, activation of factor XII dissolved in buffer, protein cocktail, heat-denatured serum, and FXI deficient plasma does not exhibit activator surface-area dependence. Instead, a highly-variable burst of procoagulant-enzyme yield is measured that exhibits no measurable kinetics, sensitivity to mixing, or solution-temperature dependence. Thus, FXII activation in both buffer and protein-containing solutions does not exhibit characteristics of a biochemical reaction but rather appears to be a "mechanochemical" reaction induced by FXII molecule interactions with hydrophilic activator particles that do not formally adsorb blood proteins from solution. Results strongly suggest that activator surface-area dependence observed in contact activation of plasma coagulation does not solely arise at the FXII activation step of the intrinsic pathway.

  3. Utilization of maize husk (Zea mays L.) as low-cost adsorbent in removal of iron from aqueous solution.

    PubMed

    Indah, S; Helard, D; Sasmita, A

    2016-01-01

    Adsorption of iron from aqueous solution by using maize husk (Zea mays L.) as a low-cost adsorbent was studied. Batch experiments were carried out at ambient temperature, 0.075-0.250 mm of particle size and 100 rpm of agitation speed to determine the influence of initial pH, adsorbent dose, initial concentration and contact time on the removal of iron. Langmuir and Freundlich models were applied to describe the adsorption isotherm of iron by maize husk. The results showed that optimum condition of iron removal were 4 of pH solution, 20 g/L of adsorbent dose, 10 mg/L of Fe concentration and 15 min of contact time of adsorption with 0.499 mg Fe/g maize husk of adsorption capacity. Experimental data fitted well to Langmuir's adsorption equilibrium isotherm within the concentration range studied. This study demonstrated that maize husk, which is an agricultural waste, has potential for iron removal from groundwater or other polluted waters. PMID:27332838

  4. Influence of dosage and chemical restraints on feline excretory urography.

    PubMed

    Ajadi, R A; Adetunji, A; Omoerah, V O; Okoh, J U

    2006-12-01

    Three series of trials involving 10 domestic short-haired cats were carried out to determine the influence of dosage of contrast media or type of chemical restraint on feline excretory urography. The 1st series (group A) involved 5 cats sedated with 2.0 mg/kg intramuscular (i.m) injection of 2% xylazine and receiving 800 mg/kg of 76 % meglumine diatrizoate (urografin). The 2nd series (group B) involved another 5 cats sedated with 2.0 mg/kg (i.m) injection of 2% xylazine and receiving 1200 mg/kg of 76% urografin. The 3rd series (group C) involved the repeat urography of the group B cats but sedated with 15 mg/kg (i.m) injection of 5% ketamine hydrochloride. Ventrodorsal radiographs were obtained immediately, 5, 15 and 40 minutes after the injection of 76% urografin. Scores were assigned to nephrographic opacification as described in the literature. The heart rates, respiratory rates and rectal temperatures of the cats were also determined before sedation, after sedation, immediately after the injection of 76% urografin and at 15-minute intervals over a period of 60 minutes. In this study, there were significant differences (P < 0.05) in the nephrographic opacification scores between the group A and group B cats at times 0 and 40 minutes post-administration of urografin. Group A cats had good initial nephrographic opacification which faded later while the nephrographic opacification of group B cats progressively increased. Similarly, nephrographic opacification was significantly (P < 0.05) higher in the xylazine-sedated cats (groups A and B) than the ketamine-sedated cats (group C). However, there were no significant differences (P > 0.05) in heart rates, respiratory rates and rectal temperatures between the 3 groups of cats. It was therefore concluded that increasing the dosage of urografin above 800 mg/kg in cats does not provide additional beneficial effects on the nephrograms produced. Xylazine sedation was observed to produce better nephrographic opacification

  5. Relative Bioavailability of Scopolamine Dosage Forms and Interaction with Dextroamphetamine

    NASA Technical Reports Server (NTRS)

    Boyd, Jason L.; Du, Brian; Vaksman, Zalman; Locke, James P.; Putcha, Lakshmi

    2007-01-01

    The NASA Reduced Gravity Office (RGO) uses scopolamine (SCOP) and in combination with dextoamphetamine (DEX) to manage motion sickness symptoms during parabolic flights. The medications are dispensed as custom dosage forms as gelatin capsules. Anecdotal evidence of efficacy suggests that these formulations are unreliable and less efficacious for the treatment of motion sickness. We estimated bioavailability of four different oral formulations used by NASA for the treatment of motion sickness. Twelve healthy, non-smoking subjects between 21and 48 years of age received four treatments on separate days in a randomized fashion; the treatments were 0.8 mg SCOP alone as tablet, 0.8 mg SCOP alone in gel cap, 0.8 mg SCOP and 10 mg DEX as tablets, and 0.8 mg SCOP and 10 mg DEX in gel cap. After each treatment, blood, saliva, and urine samples were collected at scheduled time intervals for 24 h after dosing. Bioavailability and pharmacokinetic parameters were calculated and compared using ANOVA. After administration of SCOP tablets alone, maximum concentration (C(sub max)) and time for maximum concentration (t(sub max)) were 0.26 plus or minus 0.04 ng/mL and 0.71 plus or minus 0.02 h, respectively; volume of distribution, and clearance were 47.6 plus or minus 4.72 L/kg and 23.0 plus or minus 4.58 L/h/kg, respectively. SCOP t(sub max) after administration as gelcaps was significantly longer than that with tablets (1.04 h, p less than 0.05), but no significant differences in other pharmacokinetic parameters of SCOP were observed between the two dosage forms. When coadministered with DEX, the area underneath the concentration versus time curve (AUC) of SCOP was significantly reduced to 0.61 plus or minus 0.09 and 0.64 plus or minus 0.11 ng (raised dot) h/mL after administration as a tablet or gelcap formulation, respectively; SCOP C(sub max) was lower after coadministration with DEX, this difference, however, was not statistically significant. Delayed absorption with gelcaps

  6. Contact and fumigant toxicity of a botanical-based feeding deterrent of the stable fly, Stomoxys calcitrans (Diptera: Muscidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The toxicity of several plant essential oils and some ingredient compounds was evaluated by contact and fumigant toxicity bioassays. Among the three test plant essential oils, catnip at a 20-mg dosage showed the strongest toxicity against stable flies, with the shortest knock-down time (~7 min) and ...

  7. Thermal contact conductance for cylindrical and spherical contacts

    NASA Astrophysics Data System (ADS)

    Sunil Kumar, S.; Abilash, P. M.; Ramamurthi, K.

    A prediction methodology based on Monte-Carlo simulation model, developed for flat conforming surfaces in contact, is modified and extended to predict contact conductance between curvilinear surfaces like cylinders and spheres. Experiments are also conducted in vacuum for the measurement of contact conductance between stainless steel and aluminium cylindrical contacts and stainless steel spherical contacts over a range of contact pressures. The contact conductance between cylindrical and spherical bodies is, in general, about an order of magnitude lower than for flat surfaces in contact. Increase of surface roughness and decrease in contact pressure lowers the contact conductance. However, the influence of these parameters is larger than those obtained for flat surfaces. The prediction for different parametric conditions agree closely with those measured in the experiments.

  8. Mechanical properties of hexadecane-water interfaces with adsorbed hydrophobic bacteria

    NASA Astrophysics Data System (ADS)

    Kang, Zhewen

    Certain strains of hydrophobic bacteria are known to play critical roles in petroleum-related applications. The aim of this study was to investigate how hydrophobic bacteria in their stationary phase could adsorb onto the hexadecane-water interface and alter its mechanical properties. The two strains of bacteria used in forming the interfacial films were Acinetobacter venetianus RAG-1 (a Gram-negative bacterium) and Rhodococcus erythropolis 20S-E1-c (Gram-positive). Experiments at two different length scales (millimetre and micrometre) were conducted and the results were compared. In addition, a simple flow experiment was designed in a constricted channel and the results were related to the intrinsic mechanical properties of bacteria-adsorbed films. On the millimetre scale, using the pendant drop technique, the film interfacial tension was monitored as the surface area was made to undergo changes. Under static conditions, both types of bacteria showed no significant effect on the interfacial tension. When subjected to transient excitations, the two bacterial films exhibited qualitatively similar, yet quantitative distinct rheological properties (including film elasticities and relaxation times). Under continuous reduction of surface area, the RAG-1 system showed a "paper-like" interface, while the interface of the 20S-E1-c system was "soap film-like." These macroscopic observations could be explained by the surface ultrastructures of the two cell strains. On the micrometre scale, using the micropipette technique, colloidal stability of the bacteria-coated oil droplets was examined through direct-contact experiments. Both types of bacteria were seen to function as effective stabilizers. In addition, the adsorbed bacteria also interacted with one another at the interface, giving rise to higher order 2-D rheological properties. A technique of directly probing the mechanical properties of the emulsion drop surfaces revealed that (a) the films behaved as purely elastic

  9. Contact: Releasing the news

    NASA Astrophysics Data System (ADS)

    Pinotti, Roberto

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

  10. [Contact allergies in musicians].

    PubMed

    Gasenzer, E R; Neugebauer, E A M

    2012-12-01

    During the last years, the problem of allergic diseases has increased. Allergies are errant immune responses to a normally harmless substance. In musicians the allergic contact dermatitis to exotic woods is a special problem. Exotic rosewood contains new flavonoids, which trigger an allergic reaction after permanent contact with the instrument. High quality woodwind instruments such as baroque flute or clarinets are made in ebony or palisander because of its great sound. Today instruments for non-professional players are also made in these exotic materials and non-professionals may have the risk to develop contact dermatitis, too. Brass-player has the risk of an allergic reaction to the different metals contained in the metal sheets of modern flutes and brass instruments. Specially nickel and brass alloys are used to product flute tubes or brass instruments. Special problem arises in children: patients who are allergic to plants or foods have a high risk to develop contact dermatitis. Parents don't know the materials of low-priced instruments for beginners. Often unknown cheap woods from exotic areas are used. Low-priced brass instruments contain high amount of brass and other cheap metals. Physicians should advice musician-patients or parents about the risks of the different materials and look for the reason of eczema on mouth, face, or hands. PMID:23233303

  11. [Current contact allergens].

    PubMed

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

    2011-10-01

    Ever-changing exposure to contact allergens, partly due to statutory directives (e.g. nickel, chromate, methyldibromo glutaronitrile) or recommendations from industrial associations (e.g. hydroxyisohexyl 3-cyclohexene carboxaldehyde), requires on-going epidemiologic surveillance of contact allergy. In this paper, the current state with special focus in fragrances and preservatives is described on the basis of data of the Information Network of Departments of Dermatology (IVDK) of the year 2010. In 2010, 12,574 patients were patch tested in the dermatology departments belonging to the IVDK. Nickel is still the most frequent contact allergen. However the continuously improved EU nickel directive already has some beneficial effect; sensitization frequency in young women is dropping. In Germany, chromate-reduced cement has been in use now for several years, leading to a decline in chromate sensitization in brick-layers. Two fragrance mixes are part of the German baseline series; they are still relevant. The most important fragrances in these mixes still are oak moss absolute and hydroxyisohexyl 3-cyclohexene carboxaldehyde. However, in relation to these leading allergens, sensitization frequency to other fragrances contained in the mixes seems to be increasing. Among the preservatives, MCI/MI has not lost its importance as contact allergen, in contrast to MDBGN. Sources of MCI/MI sensitization obviously are increasingly found in occupational context. Methylisothiazolinone is a significant allergen in occupational settings, and less frequently in body care products. PMID:21901563

  12. Thermal Contact Conductance

    NASA Technical Reports Server (NTRS)

    Salerno, Louis J.; Kittel, Peter

    1997-01-01

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

  13. Multigrid contact detection method

    NASA Astrophysics Data System (ADS)

    He, Kejing; Dong, Shoubin; Zhou, Zhaoyao

    2007-03-01

    Contact detection is a general problem of many physical simulations. This work presents a O(N) multigrid method for general contact detection problems (MGCD). The multigrid idea is integrated with contact detection problems. Both the time complexity and memory consumption of the MGCD are O(N) . Unlike other methods, whose efficiencies are influenced strongly by the object size distribution, the performance of MGCD is insensitive to the object size distribution. We compare the MGCD with the no binary search (NBS) method and the multilevel boxing method in three dimensions for both time complexity and memory consumption. For objects with similar size, the MGCD is as good as the NBS method, both of which outperform the multilevel boxing method regarding memory consumption. For objects with diverse size, the MGCD outperform both the NBS method and the multilevel boxing method. We use the MGCD to solve the contact detection problem for a granular simulation system based on the discrete element method. From this granular simulation, we get the density property of monosize packing and binary packing with size ratio equal to 10. The packing density for monosize particles is 0.636. For binary packing with size ratio equal to 10, when the number of small particles is 300 times as the number of big particles, the maximal packing density 0.824 is achieved.

  14. Compact contacting device

    NASA Technical Reports Server (NTRS)

    Acharya, Arun (Inventor); Gottzmann, Christian F. (Inventor); Lockett, Michael J. (Inventor); Schneider, James S. (Inventor); Victor, Richard A. (Inventor); Zawierucha, Robert (Inventor)

    1994-01-01

    An apparatus comprising a rotatable mass of structured packing for mass or heat transfer between two contacting fluids of different densities wherein the packing mass is made up of corrugated sheets of involute shape relative to the axis of the packing mass and form a logarithmic spiral curved counter to the direction of rotation.

  15. Religious Allergic Contact Dermatitis.

    PubMed

    Goldenberg, Alina; Matiz, Catalina; Eichenfield, Lawrence F

    2015-01-01

    Henna, derived from a combination of natural leaves and coloring additives, is a common decorative dye traditionally used in many Islamic religious celebrations. Para-phenylenediamine (PPD), a major component of black henna tattoo, is a strong sensitizer and common allergen. We report a case of severe connubial allergic contact dermatitis after black henna heterotransfer in a girl. PMID:25968562

  16. Have Confidence in Contact

    ERIC Educational Resources Information Center

    Crisp, Richard J.; Turner, Rhiannon N.

    2010-01-01

    In an article in the May-June 2009 "American Psychologist," we discussed a new approach to reducing prejudice and encouraging more positive intergroup relations (Crisp & Turner, 2009). We named the approach imagined intergroup contact and defined it as "the mental simulation of a social interaction with a member or members of an outgroup category"…

  17. Evolution of dosage compensation in Diptera: the gene maleless implements dosage compensation in Drosophila (Brachycera suborder) but its homolog in Sciara (Nematocera suborder) appears to play no role in dosage compensation.

    PubMed Central

    Ruiz, M F; Esteban, M R; Doñoro, C; Goday, C; Sánchez, L

    2000-01-01

    In Drosophila melanogaster and in Sciara ocellaris dosage compensation occurs by hypertranscription of the single male X chromosome. This article reports the cloning and characterization in S. ocellaris of the gene homologous to maleless (mle) of D. melanogaster, which implements dosage compensation. The Sciara mle gene produces a single transcript, encoding a helicase, which is present in both male and female larvae and adults and in testes and ovaries. Both Sciara and Drosophila MLE proteins are highly conserved. The affinity-purified antibody to D. melanogaster MLE recognizes the S. ocellaris MLE protein. In contrast to Drosophila polytene chromosomes, where MLE is preferentially associated with the male X chromosome, in Sciara MLE is found associated with all chromosomes. Anti-MLE staining of Drosophila postblastoderm male embryos revealed a single nuclear dot, whereas Sciara male and female embryos present multiple intranuclear staining spots. This expression pattern in Sciara is also observed before blastoderm stage, when dosage compensation is not yet set up. The affinity-purified antibodies against D. melanogaster MSL1, MSL3, and MOF proteins involved in dosage compensation also revealed no differences in the staining pattern between the X chromosome and the autosomes in both Sciara males and females. These results lead us to propose that different proteins in Drosophila and Sciara would implement dosage compensation. PMID:11102379

  18. A System for Dosage-Based Functional Genomics in Poplar[OPEN

    PubMed Central

    2015-01-01

    Altering gene dosage through variation in gene copy number is a powerful approach to addressing questions regarding gene regulation, quantitative trait loci, and heterosis, but one that is not easily applied to sexually transmitted species. Elite poplar (Populus spp) varieties are created through interspecific hybridization, followed by clonal propagation. Altered gene dosage relationships are believed to contribute to hybrid performance. Clonal propagation allows for replication and maintenance of meiotically unstable ploidy or structural variants and provides an alternative approach to investigating gene dosage effects not possible in sexually propagated species. Here, we built a genome-wide structural variation system for dosage-based functional genomics and breeding of poplar. We pollinated Populus deltoides with gamma-irradiated Populus nigra pollen to produce >500 F1 seedlings containing dosage lesions in the form of deletions and insertions of chromosomal segments (indel mutations). Using high-precision dosage analysis, we detected indel mutations in ∼55% of the progeny. These indels varied in length, position, and number per individual, cumulatively tiling >99% of the genome, with an average of 10 indels per gene. Combined with future phenotype and transcriptome data, this population will provide an excellent resource for creating and characterizing dosage-based variation in poplar, including the contribution of dosage to quantitative traits and heterosis. PMID:26320226

  19. 21 CFR 524.981 - Fluocinolone acetonide ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Fluocinolone acetonide ophthalmic and topical... AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.981 Fluocinolone acetonide ophthalmic and topical dosage forms....

  20. 10 CFR 35.63 - Determination of dosages of unsealed byproduct material for medical use.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Determination of dosages of unsealed byproduct material for medical use. 35.63 Section 35.63 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL General Technical Requirements § 35.63 Determination of dosages of unsealed byproduct material for medical use. (a) A licensee shall...

  1. 21 CFR 529.1044 - Gentamicin sulfate in certain other dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Gentamicin sulfate in certain other dosage forms. 529.1044 Section 529.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... § 529.1044 Gentamicin sulfate in certain other dosage forms....

  2. 21 CFR 524.1044 - Gentamicin sulfate ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Gentamicin sulfate ophthalmic and topical dosage forms. 524.1044 Section 524.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... NEW ANIMAL DRUGS § 524.1044 Gentamicin sulfate ophthalmic and topical dosage forms....

  3. 21 CFR 529.1044 - Gentamicin sulfate in certain other dosage forms.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Gentamicin sulfate in certain other dosage forms. 529.1044 Section 529.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... § 529.1044 Gentamicin sulfate in certain other dosage forms....

  4. 21 CFR 524.1044 - Gentamicin sulfate ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Gentamicin sulfate ophthalmic and topical dosage forms. 524.1044 Section 524.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... NEW ANIMAL DRUGS § 524.1044 Gentamicin sulfate ophthalmic and topical dosage forms....

  5. 21 CFR 524.1044 - Gentamicin sulfate ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Gentamicin sulfate ophthalmic and topical dosage forms. 524.1044 Section 524.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... NEW ANIMAL DRUGS § 524.1044 Gentamicin sulfate ophthalmic and topical dosage forms....

  6. 21 CFR 529.1044 - Gentamicin in certain other dosage forms.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Gentamicin in certain other dosage forms. 529.1044 Section 529.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Gentamicin in certain other dosage forms....

  7. 21 CFR 524.1044 - Gentamicin sulfate ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Gentamicin sulfate ophthalmic and topical dosage forms. 524.1044 Section 524.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... NEW ANIMAL DRUGS § 524.1044 Gentamicin sulfate ophthalmic and topical dosage forms....

  8. 21 CFR 524.1044 - Gentamicin ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Gentamicin ophthalmic and topical dosage forms. 524.1044 Section 524.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... ANIMAL DRUGS § 524.1044 Gentamicin ophthalmic and topical dosage forms....

  9. 21 CFR 529.1044 - Gentamicin sulfate in certain other dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Gentamicin sulfate in certain other dosage forms. 529.1044 Section 529.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... § 529.1044 Gentamicin sulfate in certain other dosage forms....

  10. 21 CFR 529.1044 - Gentamicin sulfate in certain other dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Gentamicin sulfate in certain other dosage forms. 529.1044 Section 529.1044 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... § 529.1044 Gentamicin sulfate in certain other dosage forms....

  11. 21 CFR 524.390 - Chloramphenicol ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Chloramphenicol ophthalmic and topical dosage forms. 524.390 Section 524.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... NEW ANIMAL DRUGS § 524.390 Chloramphenicol ophthalmic and topical dosage forms....

  12. 21 CFR 522.1696 - Penicillin G procaine injectable dosage forms.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Penicillin G procaine injectable dosage forms. 522.1696 Section 522.1696 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... ANIMAL DRUGS § 522.1696 Penicillin G procaine injectable dosage forms....

  13. 21 CFR 524.1881 - Prednisolone acetate ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Prednisolone acetate ophthalmic and topical dosage forms. 524.1881 Section 524.1881 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... NEW ANIMAL DRUGS § 524.1881 Prednisolone acetate ophthalmic and topical dosage forms....

  14. 21 CFR 524.1881 - Prednisolone acetate ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Prednisolone acetate ophthalmic and topical dosage forms. 524.1881 Section 524.1881 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... NEW ANIMAL DRUGS § 524.1881 Prednisolone acetate ophthalmic and topical dosage forms....

  15. 21 CFR 524.1881 - Prednisolone acetate ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Prednisolone acetate ophthalmic and topical dosage forms. 524.1881 Section 524.1881 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... NEW ANIMAL DRUGS § 524.1881 Prednisolone acetate ophthalmic and topical dosage forms....

  16. 21 CFR 524.1881 - Prednisolone acetate ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Prednisolone acetate ophthalmic and topical dosage forms. 524.1881 Section 524.1881 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... NEW ANIMAL DRUGS § 524.1881 Prednisolone acetate ophthalmic and topical dosage forms....

  17. 21 CFR 522.2444 - Sodium thiopental implantation or injectable dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium thiopental implantation or injectable... AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.2444 Sodium thiopental implantation or injectable dosage forms....

  18. 21 CFR 520.1802 - Piperazine-carbon disulfide complex oral dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Piperazine-carbon disulfide complex oral dosage forms. 520.1802 Section 520.1802 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... § 520.1802 Piperazine-carbon disulfide complex oral dosage forms....

  19. 21 CFR 520.1802 - Piperazine-carbon disulfide complex oral dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Piperazine-carbon disulfide complex oral dosage forms. 520.1802 Section 520.1802 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... § 520.1802 Piperazine-carbon disulfide complex oral dosage forms....

  20. 21 CFR 520.1802 - Piperazine-carbon disulfide complex oral dosage forms.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Piperazine-carbon disulfide complex oral dosage forms. 520.1802 Section 520.1802 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... § 520.1802 Piperazine-carbon disulfide complex oral dosage forms....

  1. 21 CFR 520.1802 - Piperazine-carbon disulfide complex oral dosage forms.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Piperazine-carbon disulfide complex oral dosage forms. 520.1802 Section 520.1802 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... § 520.1802 Piperazine-carbon disulfide complex oral dosage forms....

  2. 21 CFR 520.1802 - Piperazine-carbon disulfide complex oral dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Piperazine-carbon disulfide complex oral dosage forms. 520.1802 Section 520.1802 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... § 520.1802 Piperazine-carbon disulfide complex oral dosage forms....

  3. 21 CFR 522.1662 - Oxytetracycline hydrochloride implantation or injectable dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Oxytetracycline hydrochloride implantation or injectable dosage forms. 522.1662 Section 522.1662 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.1662 Oxytetracycline hydrochloride implantation or...

  4. Radiation grafted adsorbents for newly emerging environmental applications

    NASA Astrophysics Data System (ADS)

    Mahmoud Nasef, Mohamed; Ting, T. M.; Abbasi, Ali; Layeghi-moghaddam, Alireza; Sara Alinezhad, S.; Hashim, Kamaruddin

    2016-01-01

    Radiation induced grafting (RIG) is acquired to prepare a number of adsorbents for newly emerging environmental applications using a single route involving RIG of glycidymethacrylate (GMA) onto polyethylene-polypropylene (PE-PP) non-woven fabric. The grafted fabric was subjected to one of three functionalization reactions to impart desired ionic characters. This included treatment with (1) N-dimethyl-D-glucamine, (2) triethylamine and (3) triethylamine and alkalisation with KOH. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) were used to study the changes in chemical and physical structures of the obtained fibrous adsorbents. The potential applications of the three adsorbents for removal of boron from solutions, capturing CO2 from CO2/N2 mixtures and catalysing transesterification of triacetin/methanol to methyl acetate (biodiesel) were explored. The obtained fibrous adsorbents provide potential alternatives to granular resins for the investigated applications and require further development.

  5. SUPERCRITICAL FLUID EXTRACTION OF PARTICULATE AND ADSORBENT MATERIALS

    EPA Science Inventory

    The report is a summary of work performed by PNL on the extraction of semivolatile organic materials (SVOCs), for example, polynuclear aromatic compounds, from various adsorbents and environmental matrices, using supercritical fluids (SCFs) as extractants. The results of the work...

  6. Anomalous thermal denaturing of proteins adsorbed to nanoparticles

    NASA Astrophysics Data System (ADS)

    Teichroeb, J. H.; Forrest, J. A.; Ngai, V.; Jones, L. W.

    2006-09-01

    We have used localized surface plasmon resonance (LSPR) to monitor the structural changes that accompany thermal denaturing of bovine serum albumin (BSA) adsorbed onto gold nanospheres of size 5nm-60nm. The effect of the protein on the LSPR was monitored by visible extinction spectroscopy. The position of the resonance is affected by the conformation of the adsorbed protein layer, and as such can be used as a very sensitive probe of thermal denaturing that is specific to the adsorbed protein. The results are compared to detailed calculations and show that full calculations can lead to significant increases in knowledge where gold nanospheres are used as biosensors. Thermal denaturing on spheres with diameter > 20 nm show strong similarity to bulk calorimetric studies of BSA in solution. BSA adsorbed on nanospheres with d ⩽ 15nm shows a qualitative difference in behavior, suggesting a sensitivity of denaturing characteristics on local surface curvature. This may have important implications for other protein-nanoparticle interactions.

  7. Removal of adsorbed gases with CO2 snow

    NASA Astrophysics Data System (ADS)

    Zito, Richard R.

    1991-09-01

    During the outgassing of orbiting astronomical observatories, the condensation of molecular species on optical surfaces can create difficulties for astronomers. The problem is particularly severe in ultraviolet astronomy where the adsorption of only a few atomic layers of some substances can be very damaging. In this paper the removal of adsorbed atomic layers using carbon dioxide snow is discussed. The rate of removal of adsorbed layers of isopropyl alcohol, Freon TF, and deionized distilled water on Teflon substrates was experimentally determined. The removal of fingerprints (containing fatty acids such as stearic acid) from optical surfaces is also demonstrated. The presence and rate of removal of the multilayers was monitored by detecting the molecular dipole field of adsorbed molecular species. For isopropyl alcohol, Freon TF (trichlorotrifluoroethane), and water adsorbed multilayers were removed in under 1.5 seconds. Fingerprint removal was much more difficult and required 20 seconds of spraying with a mixture of carbon dioxide snow flakes and atomized microdroplets of isopropyl alcohol.

  8. Electronic structure of benzene adsorbed on Ni and Cu surfaces

    SciTech Connect

    Weinelt, M.; Nilsson, A.; Wassdahl, N.

    1997-04-01

    Benzene has for a long time served as a prototype adsorption system of large molecules. It adsorbs with the molecular plane parallel to the surface. The bonding of benzene to a transition metal is typically viewed to involve the {pi} system. Benzene adsorbs weakly on Cu and strongly on Ni. It is interesting to study how the adsorption strength is reflected in the electronic structure of the adsorbate-substrate complex. The authors have used X-ray Emission (XE) and X-ray Absorption (XA) spectroscopies to selectively study the electronic states localized on the adsorbed benzene molecule. Using XES the occupied states can be studies and with XAS the unoccupied states. The authors have used beamline 8.0 and the Swedish endstation equipped with a grazing incidence x-ray spectrometer and a partial yield absorption detector. The resolution in the XES and XAS were 0.5 eV and 0.05 eV, respectively.

  9. Trace contaminant studies of HSC adsorbent. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Yieh, D. T. N.

    1978-01-01

    The adsorption and desorption of fifteen trace contaminants on HSC (polyethylenimine coated acrylic ester) adsorbent were experimentally investigated with the following two objectives: to test the removal potential and the adsorption reversibility of the selected trace contaminants, and to test the effect a preadsorbed trace contaminant has on the CO2 adsorption capacity. The experimental method for acquiring the adsorption equilibrium data used is based on the volumetric (or displacement) concept of vacuum adsorption. From the experimental results, it was found that the HSC adsorbent has good adsorption potential for contaminants of alcohol compounds, esters, and benzene compounds; whereas, adsorption of ketone compounds, oxidizing and reducing agents are detrimental to the adsorbent. In addition, all liquid contaminants reduce the CO2 capacity of HSC adsorbent.

  10. New insights into perfluorinated adsorbents for analytical and bioanalytical applications.

    PubMed

    Marchetti, Nicola; Guzzinati, Roberta; Catani, Martina; Massi, Alessandro; Pasti, Luisa; Cavazzini, Alberto

    2015-01-01

    Perfluorinated (F-) adsorbents are generally prepared by bonding perfluoro-functionalized silanes to silica gels. They have been employed for a long time essentially as media for solid-phase extraction of F-molecules or F-tagged molecules in organic chemistry and heterogeneous catalysis. More recently, this approach has been extended to proteomics and metabolomics. Owing to their unique physicochemical properties, namely fluorophilicity and proteinophilicity, and a better understanding of some fundamental aspects of their behavior, new applications of F-adsorbents in the field of environmental science and bio-affinity studies can be envisaged. In this article, we revisit the most important features of F-adsorbents by focusing, in particular, on some basic information that has been recently obtained through (nonlinear) chromatographic studies. Finally, we try to envisage new applications and possibilities that F-adsorbents will allow in the near future. PMID:25358910

  11. Adsorption of β-galactosidase on silica and aluminosilicate adsorbents

    NASA Astrophysics Data System (ADS)

    Atyaksheva, L. F.; Dobryakova, I. V.; Pilipenko, O. S.

    2015-03-01

    It is shown that adsorption of β-galactosidase of Aspergillus oryzae fungi on mesoporous and biporous silica and aluminosilicate adsorbents and the rate of the process grow along with the diameter of the pores of the adsorbent. It is found that the shape of the adsorption isotherms changes as well, depending on the texture of the adsorbent: the Michaelis constant rises from 0.3 mM for the enzyme in solution to 0.4-0.5 mM for the enzyme on a surface in the hydrolysis of o-nitrophenyl-β-D-galactopyranoside. It is concluded that β-galactosidase displays its maximum activity on the surface of biporous adsorbents.

  12. Sorption studies of Cr(VI) from aqueous solution using bio-char as an adsorbent.

    PubMed

    Hyder, A H M G; Begum, Shamim A; Egiebor, Nosa O

    2014-01-01

    The characteristics of sorption of hexavalent chromium (Cr(VI)) onto bio-char derived from wood chips (spruce, pine, and fir) were evaluated as a function of pH, initial Cr(VI) concentration and bio-char dosage using synthetic wastewater in batch tests. The initial Cr(VI) concentrations were varied between 10 and 500 mg/L to investigate equilibrium, kinetics, and isotherms of the sorption process. About 100% of Cr(VI) was removed at pH 2 with initial Cr(VI) concentration of 10 mg/L using 4 g of bio-char after 5 hours of sorption reaction. The maximum sorption capacity of the bio-char was 1.717 mg/g for an initial Cr(VI) concentration of 500 mg/L after 5 hours. The sorption kinetics of total Cr onto bio-char followed the second-order kinetic model. The Langmuir isotherm model provided the best fit for total Cr sorption onto bio-char. The bio-char used is a co-product of a down draft gasifier that uses the derived syngas to produce electricity. Bio-char as a low cost adsorbent demonstrated promising results for removal of Cr(VI) from aqueous solution. The findings of this study would be useful in designing a filtration unit with bio-char in a full-scale water and wastewater treatment plant for the Cr(VI) removal from contaminated waters. PMID:24901621

  13. Oil palm biomass as an adsorbent for heavy metals.

    PubMed

    Vakili, Mohammadtaghi; Rafatullah, Mohd; Ibrahim, Mahamad Hakimi; Abdullah, Ahmad Zuhairi; Salamatinia, Babak; Gholami, Zahra

    2014-01-01

    Many industries discharge untreated wastewater into the environment. Heavy metals from many industrial processes end up as hazardous pollutants of wastewaters.Heavy metal pollution has increased in recent decades and there is a growing concern for the public health risk they may pose. To remove heavy metal ions from polluted waste streams, adsorption processes are among the most common and effective treatment methods. The adsorbents that are used to remove heavy metal ions from aqueous media have both advantages and disadvantages. Cost and effectiveness are two of the most prominent criteria for choosing adsorbents. Because cost is so important, great effort has been extended to study and find effective lower cost adsorbents.One class of adsorbents that is gaining considerable attention is agricultural wastes. Among many alternatives, palm oil biomasses have shown promise as effective adsorbents for removing heavy metals from wastewater. The palm oil industry has rapidly expanded in recent years, and a large amount of palm oil biomass is available. This biomass is a low-cost agricultural waste that exhibits, either in its raw form or after being processed, the potential for eliminating heavy metal ions from wastewater. In this article, we provide background information on oil palm biomass and describe studies that indicate its potential as an alternative adsorbent for removing heavy metal ions from wastewater. From having reviewed the cogent literature on this topic we are encouraged that low-cost oil-palm-related adsorbents have already demonstrated outstanding removal capabilities for various pollutants.Because cost is so important to those who choose to clean waste streams by using adsorbents, the use of cheap sources of unconventional adsorbents is increasingly being investigated. An adsorbent is considered to be inexpensive when it is readily available, is environmentally friendly, is cost-effective and be effectively used in economical processes. The

  14. Mathematical modeling of drug release from lipid dosage forms.

    PubMed

    Siepmann, J; Siepmann, F

    2011-10-10

    Lipid dosage forms provide an interesting potential for controlled drug delivery. In contrast to frequently used poly(ester) based devices for parenteral administration, they do not lead to acidification upon degradation and potential drug inactivation, especially in the case of protein drugs and other acid-labile active agents. The aim of this article is to give an overview on the current state of the art of mathematical modeling of drug release from this type of advanced drug delivery systems. Empirical and semi-empirical models are described as well as mechanistic theories, considering diffusional mass transport, potentially limited drug solubility and the leaching of other, water-soluble excipients into the surrounding bulk fluid. Various practical examples are given, including lipid microparticles, beads and implants, which can successfully be used to control the release of an incorporated drug during periods ranging from a few hours up to several years. The great benefit of mechanistic mathematical theories is the possibility to quantitatively predict the effects of different formulation parameters and device dimensions on the resulting drug release kinetics. Thus, in silico simulations can significantly speed up product optimization. This is particularly useful if long release periods (e.g., several months) are targeted, since experimental trial-and-error studies are highly time-consuming in these cases. In the future it would be highly desirable to combine mechanistic theories with the quantitative description of the drug fate in vivo, ideally including the pharmacodynamic efficacy of the treatments. PMID:21802501

  15. Studies of phase transitions in the aripiprazole solid dosage form.

    PubMed

    Łaszcz, Marta; Witkowska, Anna

    2016-01-01

    Studies of the phase transitions in an active substance contained in a solid dosage form are very complicated but essential, especially if an active substance is classified as a BCS Class IV drug. The purpose of this work was the development of sensitive methods for the detection of the phase transitions in the aripiprazole tablets containing initially its form III. Aripiprazole exhibits polymorphism and pseudopolymorphism. Powder diffraction, Raman spectroscopy and differential scanning calorimetry methods were developed for the detection of the polymorphic transition between forms III and I as well as the phase transition of form III into aripiprazole monohydrate in tablets. The study involved the initial 10 mg and 30 mg tablets, as well as those stored in Al/Al blisters, a triplex blister pack and HDPE bottles (with and without desiccant) under accelerated and long term conditions. The polymorphic transition was not observed in the initial and stored tablets but it was visible on the DSC curve of the Abilify(®) 10 mg reference tablets. The formation of the monohydrate was observed in the diffractograms and Raman spectra in the tablets stored under accelerated conditions. The monohydrate phase was not detected in the tablets stored in the Al/Al blisters under long term conditions. The results showed that the Al/Al blisters can be recommended as the packaging of the aripiprazole tablets containing form III. PMID:26397209

  16. Carboxymethyl starch mucoadhesive microspheres as gastroretentive dosage form.

    PubMed

    Lemieux, Marc; Gosselin, Patrick; Mateescu, Mircea Alexandru

    2015-12-30

    Carboxymethyl starch microspheres (CMS-MS) were produced from carboxymethyl starch powder (CMS-P) with a degree of substitution (DS) from 0.1 to 1.5 in order to investigate the influence of DS on physicochemical, drug release and mucoadhesion properties as well as interactions with gastrointestinal tract (GIT) epithelial barrier models. Placebo and furosemide loaded CMS-MS were obtained by emulsion-crosslinking with sodium trimetaphosphate (STMP). DS had an impact on increasing equilibrium water uptake and modulating drug release properties of the CMS-MS according to the surrounding pH. The transepithelial electrical resistance (TEER) of NCI-N87 gastric cell monolayers was not influenced in presence of CMS-MS, whereas that of Caco-2 intestinal cell monolayers decreased with increasing DS but recovered initial values at about 15h post-treatment. CMS-MS with increasing DS also enhanced furosemide permeability across both NCI-N87 and Caco-2 monolayers at pH gradients from 3.0 to 7.4. Mucoadhesion of CMS-MS on gastric mucosa (acidic condition) increased with the DS up to 55% for a DS of 1.0 but decreased on neutral intestinal mucosa to less than 10% with DS of 0.1. The drug release, permeability enhancement and mucoadhesive properties of the CMS-MS suggest CMS-MS with DS between 0.6 and 1.0 as suitable excipient for gastroretentive oral delivery dosage forms. PMID:26456246

  17. Biowaiver Monographs for Immediate Release Solid Oral Dosage Forms: Ribavirin.

    PubMed

    Goodarzi, Navid; Barazesh Morgani, Ahmadreza; Abrahamsson, Bertil; Cristofoletti, Rodrigo; Groot, D W; Langguth, Peter; Mehta, Mehul U; Polli, James E; Shah, Vinod P; Dressman, Jennifer B

    2016-04-01

    Literature data relevant to the decision to allow a waiver of in vivo bioequivalence (BE) testing for the approval of immediate release solid oral dosage forms containing ribavirin are reviewed. Ribavirin is highly soluble, but its permeability characteristics are not well defined. Therefore according to the Biopharmaceutical Classification System, and taking a "worst case" approach, ribavirin should be assigned to class III. As ribavirin is transported across the brush border membrane of the human jejunum by hCNT2, it shows saturable uptake in the intestine. However, no common excipients have been shown to compete for ribavirin absorption, nor have problems with BE of immediate release ribavirin formulations containing different excipients and produced by different manufacturing methods been reported in the open literature. So the risk of bioinequivalence caused by these factors appears to be low. Ribavirin is considered a narrow therapeutic index drug, as judged by comparing the minimum effective concentration and minimum toxic concentrations in blood. Although ribavirin would not be eligible for approval via a Biopharmaceutical Classification System-based biowaiver procedure according to today's guidances due to its narrow therapeutic index, the risks of biowaiving should be weighed against the considerable risks associated with studying BE of ribavirin products in healthy subjects. PMID:26952879

  18. Sample sizes in dosage investigational clinical trials: a systematic evaluation.

    PubMed

    Huang, Ji-Han; Su, Qian-Min; Yang, Juan; Lv, Ying-Hua; He, Ying-Chun; Chen, Jun-Chao; Xu, Ling; Wang, Kun; Zheng, Qing-Shan

    2015-01-01

    The main purpose of investigational phase II clinical trials is to explore indications and effective doses. However, as yet, there is no clear rule and no related published literature about the precise suitable sample sizes to be used in phase II clinical trials. To explore this, we searched for clinical trials in the ClinicalTrials.gov registry using the keywords "dose-finding" or "dose-response" and "Phase II". The time span of the search was September 20, 1999, to December 31, 2013. A total of 2103 clinical trials were finally included in our review. Regarding sample sizes, 1,156 clinical trials had <40 participants in each group, accounting for 55.0% of the studies reviewed, and only 17.2% of the studies reviewed had >100 patient cases in a single group. Sample sizes used in parallel study designs tended to be larger than those of crossover designs (median sample size 151 and 37, respectively). In conclusion, in the earlier phases of drug research and development, there are a variety of designs for dosage investigational studies. The sample size of each trial should be comprehensively considered and selected according to the study design and purpose. PMID:25609916

  19. REFLECTIONS ON QUALITY AND DOSAGE OF PRESCHOOL AND CHILDREN'S DEVELOPMENT.

    PubMed

    Votruba-Drzal, Elizabeth; Miller, Portia

    2016-06-01

    This ambitious monograph tackles several important questions related to children's preschool experiences that have relevance for program and policy initiatives at the state and federal levels. The authors' approach is rigorous: they conduct parallel analyses across eight large and diverse studies of preschool children in center care and use meta-analysis to summarize patterns across studies. The study finds nonlinear associations between preschool quality and gains in language and literacy skills, with larger associations in higher versus lower quality classrooms. Results also show that domain-specific measures of preschool quality were more strongly related to children's development than global quality measures. The "dosage" of preschool was likewise important: more years in Head Start predicted larger vocabulary and literacy gains, whereas more time spent on instruction predicted greater literacy and math skills growth. In this commentary, we situate these findings in the broader literature addressing links between preschool experiences and children's development and discuss key takeaways for research, practice, and policy. PMID:27273510

  20. [Oral dosage forms for children: acceptability and palatability].

    PubMed

    Kojima, Jun

    2015-01-01

    Children generally reject taking medicine which does not have a favorable shape, taste, flavor, etc. However, if a child who needs to take a medicine, rejects taking it, he might never recover from his condition. When a child is unable to take medicine orally, it is intravenously administered, and he and his caregivers then may experience stress. Syrups and suspensions are considered as favorable types of dosage forms in which to orally administer medicine to infants and children. However, they may have disadvantages such as solubility, a bad taste, portability problems or required refrigerator storage. World Health Organization (WHO) currently favors that infants and children be treated with oral solid medicines. New oral solid tablets, such as a mini-tablet, instead of liquid medicines are proposed for this group, however, there are a few reports that mini-tablets are suitable for infants and children. Palatability is one of the main elements of patient acceptability of an oral pediatric medicine. Palatability is defined as the overall appreciation of an oral medicinal product in relation to its smell, taste, aftertaste and feeling in the mouth. Design of the formulation of an oral pediatric medicine should be considered together with its palatability. PMID:25747220

  1. Spectrophotometric determination of diloxanide furoate in its dosage forms.

    PubMed

    Al-Ghanam, S M; Belal, F

    2001-09-01

    A simple and sensitive spectrophotometric method has been developed for the determination of diloxanide furoate in its dosage forms. The method is based on the reaction of the drug with potassium permanganate in the presence of sodium hydroxide to produce a bluish green coloured species measurable at 610 nm. The absorbance-concentration plot is linear over the range 2.5-20 microg/ml with correlation coefficient (n = 8) of 0.9998 and minimum detectability of 0.2 microg/ml (6.1 x 10(-7) M). The molar absorptivity was 1.1 x 10(4) l/mol cm. The different experimental parameters affecting the development and stability of the colour were carefully studied and optimised. The proposed method was applied successfully for the determination of diloxanide furoate in its tablet form. The results obtained were in good agreement with those obtained using the official method. The proposed method could be applied to the determination of diloxanide furoate in presence of some co-formulated drugs. The effect of sensitisers and surfactants on the performance of the proposed method was also studied. A proposal of the reaction pathway was presented. PMID:11680811

  2. An interface model for dosage adjustment connects hematotoxicity to pharmacokinetics.

    PubMed

    Meille, C; Iliadis, A; Barbolosi, D; Frances, N; Freyer, G

    2008-12-01

    When modeling is required to describe pharmacokinetics and pharmacodynamics simultaneously, it is difficult to link time-concentration profiles and drug effects. When patients are under chemotherapy, despite the huge amount of blood monitoring numerations, there is a lack of exposure variables to describe hematotoxicity linked with the circulating drug blood levels. We developed an interface model that transforms circulating pharmacokinetic concentrations to adequate exposures, destined to be inputs of the pharmacodynamic process. The model is materialized by a nonlinear differential equation involving three parameters. The relevance of the interface model for dosage adjustment is illustrated by numerous simulations. In particular, the interface model is incorporated into a complex system including pharmacokinetics and neutropenia induced by docetaxel and by cisplatin. Emphasis is placed on the sensitivity of neutropenia with respect to the variations of the drug amount. This complex system including pharmacokinetic, interface, and pharmacodynamic hematotoxicity models is an interesting tool for analysis of hematotoxicity induced by anticancer agents. The model could be a new basis for further improvements aimed at incorporating new experimental features. PMID:19107581

  3. Residence time determination for adsorbent beds of different configurations

    SciTech Connect

    Otermat, J.E.; Wikoff, W.O.; Kovach, J.L.

    1995-02-01

    The residence time calculations of ASME AG-1 Code, Section FC, currently specify a screen surface area method, that is technically incorrect. Test data has been obtained on Type II adsorber trays of different configurations to establish residence time in the adsorber trays. These data indicate that the air volume/carbon volume ratio or the average screen area are more appropriate for the calculation of the residence time calculation than the currently used, smallest screen area basis.

  4. Feedback Control of Sex Determination by Dosage Compensation Revealed through Caenorhabditis Elegans Sdc-3 Mutations

    PubMed Central

    DeLong, L.; Plenefisch, J. D.; Klein, R. D.; Meyer, B. J.

    1993-01-01

    In Caenorhabditis elegans, sex determination and dosage compensation are coordinately controlled through a group of genes that respond to the primary sex determination signal. Here we describe a new gene, sdc-3, that also controls these processes. In contrast to previously described genes, the sex determination and dosage compensation activities of sdc-3 are separately mutable, indicating that they function independently. Paradoxically, the sdc-3 null phenotype fails to reveal the role of sdc-3 in sex determination: sdc-3 null mutations that lack both activities disrupt dosage compensation but cause no overt sexual transformation. We demonstrate that the dosage compensation defect of sdc-3 null alleles suppresses their sex determination defect. This self-suppression phenomenon provides a striking example of how a disruption in dosage compensation can affect sexual fate. We propose that the suppression occurs via a feedback mechanism that acts at an early regulatory step in the sex determination pathway to promote proper sexual identity. PMID:8462848

  5. Evolution of dosage compensation under sexual selection differs between X and Z chromosomes

    PubMed Central

    Mullon, Charles; Wright, Alison E.; Reuter, Max; Pomiankowski, Andrew; Mank, Judith E.

    2015-01-01

    Complete sex chromosome dosage compensation has more often been observed in XY than ZW species. In this study, using a population genetic model and the chicken transcriptome, we assess whether sexual conflict can account for this difference. Sexual conflict over expression is inevitable when mutation effects are correlated across the sexes, as compensatory mutations in the heterogametic sex lead to hyperexpression in the homogametic sex. Coupled with stronger selection and greater reproductive variance in males, this results in slower and less complete evolution of Z compared with X dosage compensation. Using expression variance as a measure of selection strength, we find that, as predicted by the model, dosage compensation in the chicken is most pronounced in genes that are under strong selection biased towards females. Our study explains the pattern of weak dosage compensation in ZW systems, and suggests that sexual selection plays a major role in shaping sex chromosome dosage compensation. PMID:26212613

  6. Calculator programs to deal with non-steady state, multiple dosage regimen clinical pharmacokinetics.

    PubMed

    Ensom, R J; Nakagawa, R S

    1983-07-01

    Serum drug levels have become a useful tool in the optimization of dosage requirements for several therapeutically important drugs. In the acute care situation the interpretation of these levels is complicated by multiple dosage regimens and inadequate time to achieve steady-state serum drug levels. Mathematical equations describing first order single compartment pharmacokinetics have been compiled. An alpha-numeric programmable calculator has been programmed to accept information regarding up to seven different serial dosage regimens. The calculator is also programmed to predict concentrations at any time during a complex set of dosage regimens or peak, trough, and average concentrations given a maintenance dosage regimen. Examples are given to demonstrate the usefulness of the programs in the clinical setting. PMID:6688607

  7. The effect of load in a contact with boundary lubrication. [reduction of coefficient of friction

    NASA Technical Reports Server (NTRS)

    Georges, J. M.; Lamy, B.; Daronnat, M.; Moro, S.

    1978-01-01

    The effect of the transition load on the wear in a contact with boundary lubrication was investigated. An experimental method was developed for this purpose, and parameters affecting the boundary lubrication under industrial operating conditions were identified. These parameters are the adsorbed boundary film, the contact microgeometry (surface roughness), macrogeometry, and hardness of materials used. It was found that the curve of the tops of the surface protrustion affect the transition load, and thus the boundary lubrication. The transition load also depends on the chemical nature of the contact and its geometrical and mechanical aspects.

  8. Schiff base - Chitosan grafted L-monoguluronic acid as a novel solid-phase adsorbent for removal of congo red.

    PubMed

    Yuan, Bo; Qiu, Li-Gan; Su, Hong-Zhen; Cao, Cheng-Liang; Jiang, Ji-Hong

    2016-01-01

    A novel modified chitosan adsorbent (GL-SBCS) was synthesized by covalently grafting a Schiff base-chitosan (SBCS) onto the surface of l-monoguluronic acid. Physico-chemical investigation on the adsorption of congo red, an anionic azo dye by GL-SBCS has been carried out. The effect of different weight contents of chitosan in GL-SBCS composite, adsorbent dosage, initial pH and contract time were studied in detail using batch adsorption. Results showed that GL-SBCS exhibited better than normal CS and l-monoguluronic acid. Further investigation demonstrated that the adsorption pattern fitted well with the Langmuir model (R(2)>0.99) but less-satisfied the Freundlich model. Both ionic interaction as well as physical forces is responsible for binding of congo red with GL-SBCS as determined by zeta potential measurement Both sodium chloride and sodium dodecyl sulfate significantly influenced the adsorption process. SBCS would be a good method and resource to increase absorption efficiency for the removal of anionic dyes in a wastewater treatment process. PMID:26432372

  9. Efforts to Consolidate Chalcogels with Adsorbed Iodine

    SciTech Connect

    Riley, Brian J.; Pierce, David A.; Chun, Jaehun

    2013-08-28

    This document discusses ongoing work with non-oxide aerogels, called chalcogels, that are under development at the Pacific Northwest National Laboratory as sorbents for gaseous iodine. Work was conducted in fiscal year 2012 to demonstrate the feasibility of converting Sn2S3 chalcogel without iodine into a glass. This current document summarizes the work conducted in fiscal year 2013 to assess the consolidation potential of non-oxide aerogels with adsorbed iodine. The Sn2S3 and Sb13.5Sn5S20 chalcogels were selected for study. The first step in the process for these experiments was to load them with iodine (I2). The I2 uptake was ~68 mass% for Sn2S3 and ~50 mass% for Sb13.5Sn5S20 chalcogels. X-ray diffraction (XRD) of both sets of sorbents showed that metal-iodide complexes were formed during adsorption, i.e., SnI4 for Sn2S3 and SbI3 for Sb13.5Sn5S20. Additionally, metal-sulfide-iodide complexes were formed, i.e., SnSI for Sn2S3 and SbSI for Sb13.5Sn5S20. No XRD evidence for unreacted iodine was found in any of these samples. Once the chalcogels had reached maximum adsorption, the consolidation potential was assessed. Here, the sorbents were heated for consolidation in vacuum-sealed quartz vessels. The Sb13.5Sn5S20 chalcogel was heated both (1) in a glassy carbon crucible within a fused quartz tube and (2) in a single-containment fused quartz tube. The Sn2S3 chalcogel was only heated in a single-containment fused quartz tube. In both cases with the single-containment fused quartz experiments, the material consolidated nicely. However, in both cases, there were small fractions of metal iodides not incorporated into the final product as well as fused quartz particles within the melt due to the sample attacking the quartz wall during the heat treatment. The Sb13.5Sn5S20 did not appear to attack the glassy carbon crucible so, for future experiments, it would be ideal to apply a coating, such as pyrolytic graphite, to the inner walls of the fused quartz vessel to prevent

  10. Evaluation of a cesium adsorbent grafted with ammonium 12-molybdophosphate

    NASA Astrophysics Data System (ADS)

    Shibata, Takuya; Seko, Noriaki; Amada, Haruyo; Kasai, Noboru; Saiki, Seiichi; Hoshina, Hiroyuki; Ueki, Yuji

    2016-02-01

    A fibrous cesium (Cs) adsorbent was developed using radiation-induced graft polymerization with a cross-linked structure containing a highly stable adsorption ligand. The ligand, ammonium 12-molybdophosphate (AMP), was successfully introduced onto the fibrous polyethylene trunk material. The resulting Cs adsorbent contained 36% nonwoven fabric polyethylene (NFPE), 1% AMP, 2% triallyl isocyanurate (TAIC) and 61% glycidyl methacrylate (GMA). The adsorbent's Cs adsorption capacity was evaluated using batch and column tests. It was determined that the adsorbent could be used in a wide pH range. The amount of desorbed molybdenum, which can be used as an estimate for AMP stability on the Cs adsorbent, was minimized at the standard drinking water pH range of 5.8-8.6. Based from the inspection on the adherence of these results to the requirements set forth by the Food Sanitation Act by a third party organization, it can be concluded that the developed Cs adsorbent can be safely utilized for drinking water.

  11. Application of Silver Impregnated Iodine Adsorbent to Nuclear Facilities

    NASA Astrophysics Data System (ADS)

    Fukasawa, Tetsuo; Nakamura, Tomotaka; Kondo, Yoshikazu; Funabashi, Kiyomi

    Radioactive iodine is one of the most important nuclides to be prevented for release from nuclear facilities and many facilities have off-gas treatment systems to minimize the volatile nuclides dispersion to the environment. Silver impregnated inorganic adsorbents were known as inflammable and stable fixing materials for iodine and the authors started to develop 25 years ago a kind of inorganic adsorbent that has better capability compared with conventional ones. Aluminum oxide (Alumina) was selected as a carrier material and silver nitrate as an impregnated one. Pore diameters were optimized to avoid the influence of impurities such as humidity in the off-gas stream at lower temperatures. Experiments and improvements were alternately conducted for the new adsorbent. The tests were carried out in various conditions to confirm the performance of the developed adsorbent, which clarified its good ability to remove iodine. Silver nitrate impregnated alumina adsorbent (AgA) has about twice the capacity for iodine adsorption and higher iodine removal efficiency at relatively high humidity than conventional ones. The AgA chemically and stably fixes radioactive iodine and fits the storage and disposal of used adsorbent. AgA is now and will be applied to nuclear power plants, reprocessing plants, and research facilities.

  12. Cryogenic adsorber design in a helium refrigeration system

    NASA Astrophysics Data System (ADS)

    Hu, Zhongjun; Zhang, Ning; Li, Zhengyu; Li, Q.

    2012-06-01

    The cryogenic adsorber is specially designed to eliminate impurities in gaseous helium such as O2, and N2 which is normally difficult to remove, based on the reversible cryotrapping of impurities on an activated carbon bed. The coconut shell activated carbon is adopted because of its developed micropore structure and specific surface area. This activated carbon adsorption is mostly determined by the micropore structure, and the adsorption rate of impurities is inversely proportional to the square of the particle sizes. The active carbon absorber's maximum permissible flow velocity is 0.25 m/s. When the gas flow velocity increases, the adsorption diffusion rate of the adsorbent is reduced, because an increase in the magnitude of the velocity resulted in a reduced amount of heat transfer to a unit volume of impure gas. According to the numerical simulation of N2 adsorption dynamics, the appropriate void tower link speed and the saturated adsorption capacity are determined. Then the diameter and height of the adsorber are designed. The mass transfer length should be taken into account in the adsorber height design. The pressure decrease is also calculated. The important factors that influence the adsorber pressure decrease are the void tower speed, the adsorbed layer height, and the active carbon particle shape and size.

  13. Friction and transfer of copper, silver, and gold to iron in the presence of various adsorbed surface films

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1979-01-01

    Sliding friction experiments were conducted with the noble metals copper, silver, and gold and two binary alloys of these metals contacting iron in the presence of various adsorbates including, oxygen, methyl mercaptan, and methyl chloride. A pin on disk specimen configuration was used with a load of 100 grams, sliding velocity of 60 mm/min; at 25 C with the surfaces saturated with the adsorbates. Auger emission spectroscopy was used to monitor surface films. Results of the experiments indicate that friction and transfer characteristics are highly specific with respect to both the noble metal and surface film present. With all three metals and films transfer of the noble metal to iron occurred very rapidly. With all metals and films transfer of the noble metal to iron continuously increased with repeated passes except for silver and copper sliding on iron sulfide.

  14. A novel magnetic adsorbent based on waste litchi peels for removing Pb(II) from aqueous solution.

    PubMed

    Jiang, Ruixue; Tian, Jiyu; Zheng, Hao; Qi, Jinqiu; Sun, Shujuan; Li, Xiaochen

    2015-05-15

    A new magnetic bioadsorbent, magnetic litchi peel (MLP), was synthesized by coating powdered litchi peel with Fe3O4, and was used for removing Pb(II) from aqueous solutions. The influencing factors, adsorption isotherms, kinetics, and thermodynamics of Pb(II) adsorption by MLP were investigated using batch assays. Optimum Pb(II) adsorption by MLP was achieved using a contact time of 120 min, an adsorbent dose of 5 g/L, and pH of 6.0. The adsorption equilibrium data conformed to the Langmuir isotherm model, yielding a maximum Pb(II) adsorption capacity of 78.74 mg/g. The adsorption kinetics for Pb(II) adsorption by MLP followed a pseudo-second-order model. The thermodynamic results suggested that Pb(II) adsorption by MLP was spontaneous and exothermic. Additionally, the magnetic adsorbent was easily and rapidly separated out of solution under an external magnetic field. PMID:25770959

  15. The shaping and functional consequences of the dosage effect landscape in multiple myeloma

    PubMed Central

    2013-01-01

    Background Multiple myeloma (MM) is a malignant proliferation of plasma B cells. Based on recurrent aneuploidy such as copy number alterations (CNAs), myeloma is divided into two subtypes with different CNA patterns and patient survival outcomes. How aneuploidy events arise, and whether they contribute to cancer cell evolution are actively studied. The large amount of transcriptomic changes resultant of CNAs (dosage effect) pose big challenges for identifying functional consequences of CNAs in myeloma in terms of specific driver genes and pathways. In this study, we hypothesize that gene-wise dosage effect varies as a result from complex regulatory networks that translate the impact of CNAs to gene expression, and studying this variation can provide insights into functional effects of CNAs. Results We propose gene-wise dosage effect score and genome-wide karyotype plot as tools to measure and visualize concordant copy number and expression changes across cancer samples. We find that dosage effect in myeloma is widespread yet variable, and it is correlated with gene expression level and CNA frequencies in different chromosomes. Our analysis suggests that despite the enrichment of differentially expressed genes between hyperdiploid MM and non-hyperdiploid MM in the trisomy chromosomes, the chromosomal proportion of dosage sensitive genes is higher in the non-trisomy chromosomes. Dosage-sensitive genes are enriched by genes with protein translation and localization functions, and dosage resistant genes are enriched by apoptosis genes. These results point to future studies on differential dosage sensitivity and resistance of pro- and anti-proliferation pathways and their variation across patients as therapeutic targets and prognosis markers. Conclusions Our findings support the hypothesis that recurrent CNAs in myeloma are selected by their functional consequences. The novel dosage effect score defined in this work will facilitate integration of copy number and

  16. Contact Graph Routing

    NASA Technical Reports Server (NTRS)

    Burleigh, Scott C.

    2011-01-01

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

  17. Gold recovery from low concentrations using nanoporous silica adsorbent

    NASA Astrophysics Data System (ADS)

    Aledresse, Adil

    The development of high capacity adsorbents with uniform porosity denoted 5%MP-HMS (5% Mercaptopropyl-Hexagonal Mesoporous Structure) to extract gold from noncyanide solutions is presented. The preliminary studies from laboratory simulated noncyanide gold solutions show that the adsorption capacities of these materials are among the highest reported. The high adsorption saturation level of these materials, up to 1.9 mmol/g (37% of the adsorbent weight) from gold chloride solutions (potassium tetrachloroaurate) and 2.9 mmol/g (57% of the adsorbent weight) from gold bromide solutions (potassium tetrabromoaurate) at pH = 2, is a noteworthy feature of these materials. This gold loading from [AuC4]- and [AuBr4 ]- solutions corresponds to a relative Au:S molar ratio of 2.5:1 and 3.8:1, respectively. These rates are significantly higher than the usual 1:1 (Au:S) ratio expected for metal ion binding with the material. The additional gold ions loaded have been spontaneously reduced to metallic gold in the mesoporous material. Experimental studies indicated high maximum adsorptions of gold as high as 99.9% recovery. Another promising attribute of these materials is their favourable adsorption kinetics. The MP-HMS reaches equilibrium (saturation) in less than 1 minute of exposure in gold bromide and less than 10 minutes in gold chloride. The MP-HMS materials adsorption is significantly improved by agitation and the adsorption capacity of Au (III) ions increases with the decrease in pH. The recovery of adsorbed gold and the regeneration of spent adsorbent were investigated for MP-HMS adsorbent. The regenerated adsorbent (MP-HMS) maintained its adsorption capacity even after repeated use and all the gold was successfully recovered from the spent adsorbent. For the fist time, a promising adsorbent system has been found that is capable of effectively concentrating gold thiosulphate complexes, whereas conventional carbon-inpulp (CIP) and carbon-in-leach (CIL) systems fail. The

  18. Performance of magnetic activated carbon composite as peroxymonosulfate activator and regenerable adsorbent via sulfate radical-mediated oxidation processes.

    PubMed

    Oh, Wen-Da; Lua, Shun-Kuang; Dong, Zhili; Lim, Teik-Thye

    2015-03-01

    Magnetic activated carbon composite (CuFe2O4/AC, MACC) was prepared by a co-precipitation-calcination method. The MACC consisted of porous micro-particle morphology with homogeneously distributed CuFe2O4 and possessed high magnetic saturation moment (8.1 emu g(-1)). The performance of MACC was evaluated as catalyst and regenerable adsorbent via peroxymonosulfate (PMS, Oxone(®)) activation for methylene blue (MB) removal. Optimum CuFe2O4/AC w/w ratio was 1:1.5 giving excellent performance and can be reused for at least 3 cycles. The presence of common inorganic ions, namely Cl(-) and NO3(-) did not exert significant influence on MB degradation but humic acid decreased the MB degradation rate. As a regenerable adsorbent, negligible difference in regeneration efficiency was observed when a higher Oxone(®) dosage was employed but a better efficiency was obtained at a lower MACC loading. The factors hindering complete MACC regeneration are MB adsorption irreversibility and AC surface modification by PMS making it less favorable for subsequent MB adsorption. With an additional mild heat treatment (150 °C) after regeneration, 82% of the active sites were successfully regenerated. A kinetic model incorporating simultaneous first-order desorption, second-order adsorption and pseudo-first order degradation processes was numerically-solved to describe the rate of regeneration. The regeneration rate increased linearly with increasing Oxone(®):MACC ratio. The MACC could potentially serve as a catalyst for PMS activation and regenerable adsorbent. PMID:25463211

  19. Contact dynamics math model

    NASA Technical Reports Server (NTRS)

    Glaese, John R.; Tobbe, Patrick A.

    1986-01-01

    The Space Station Mechanism Test Bed consists of a hydraulically driven, computer controlled six degree of freedom (DOF) motion system with which docking, berthing, and other mechanisms can be evaluated. Measured contact forces and moments are provided to the simulation host computer to enable representation of orbital contact dynamics. This report describes the development of a generalized math model which represents the relative motion between two rigid orbiting vehicles. The model allows motion in six DOF for each body, with no vehicle size limitation. The rotational and translational equations of motion are derived. The method used to transform the forces and moments from the sensor location to the vehicles' centers of mass is also explained. Two math models of docking mechanisms, a simple translational spring and the Remote Manipulator System end effector, are presented along with simulation results. The translational spring model is used in an attempt to verify the simulation with compensated hardware in the loop results.

  20. Simulating Contact Binaries

    NASA Astrophysics Data System (ADS)

    Kadam, Kundan; Clayton, Geoffrey C.; Frank, Juhan; Tohline, Joel E.; Staff, Jan E.; Motl, Patrick M.; Marcello, Dominic

    2014-06-01

    About one in every 150 stars is a contact binary system of WUMa type and it was thought for a long time that such a binary would naturally proceed towards merger, forming a single star. In September 2008 such a merger was observed in the eruption of a “red nova", V1309 Sco. We are developing a hydrodynamics simulation for contact binaries using Self Consistent Field (SCF) techniques, so that their formation, structural, and merger properties could be studied. This model can also be used to probe the stability criteria such as the large-scale equatorial circulations and the minimum mass ratio. We also plan to generate light curves from the simulation data in order to compare with the observed case of V1309 Sco. A comparison between observations and simulations will help us better understand the nova-like phenomena of stellar mergers.

  1. Utility of adsorbents in the purification of drinking water: a review of characterization, efficiency and safety evaluation of various adsorbents.

    PubMed

    Dubey, Shashi Prabha; Gopal, Krishna; Bersillon, J L

    2009-05-01

    Clean drinking water is one of the implicit requisites fora healthy human population. However the growing industrialization and extensive use of chemicals for various concerns, has increased the burden of unwanted pollutants in the drinking water of developing countries like India. The entry of potentially hazardous substances into the biota has been magnifying day by day. In the absence of a possible stoppage of these, otherwise, useful chemicals, the only way to maintain safer water bodies is to develop efficient purifying technologies. One such immensely beneficial procedure that has been in use is that of purification of water using 'adsorbents'. Indigenous minerals and natural plants products have potential for removing many pollutants viz. fluoride, arsenic, nitrate, heavy metals, pesticides as well as trihalomethanes. Adsorbents which are derived from carbon, alumina, zeolite, clay minerals, iron ores, industrial by products, and natural products viz. parts of the plants, herbs and algal biomass offer promising potential of removal. In the recent years attention has been paid to develop process involving screening/pretreatment/activation/impregnation using alkalies, acids, alum, lime, manganese dioxide, ferric chloride and other chemicals which are found to enhance their adsorbing efficiency. Chemical characterization of these adsorbents recapitulates the mechanism of the process. It is imperative to observe that capacities of the adsorbents may vary depending on the characteristics, chemical modifications and concentration of the individual adsorbent. Removal kinetics is found to be based on the experimental conditions viz. pH, concentration of the adsorbate, quantity of the adsorbent and temperature. It is suggested that isotherm model is suitable tool to assess the adsorption capacities in batch and column modes. Safety evaluation and risk assessment of the process/products may be useful to provide guidelines for its sustainable disposal. PMID:20120453

  2. Removal of Direct Red 12B by garlic peel as a cheap adsorbent: Kinetics, thermodynamic and equilibrium isotherms study of removal

    NASA Astrophysics Data System (ADS)

    Asfaram, A.; Fathi, M. R.; Khodadoust, S.; Naraki, M.

    2014-06-01

    The removal of dyes from industrial waste is very important from health and hygiene point of view and for environmental protection. In this work, efficiency and performance of garlic peel (GP) adsorbent for the removal of Direct Red 12B (DR12B) from wastewater was investigated. The influence of variables including pH, concentration of the dye and amount of adsorbent, particle size, contact time and temperature on the dye removal has been investigated. It was observed that the pseudo-second-order kinetic model fits better with good correlation coefficient and the equilibrium data fitted well with the Langmuir model. More than 99% removal efficiency was obtained within 25 min at adsorbent dose of 0.2 g per 50 ml for initial dye concentration of 50 mg L-1. Calculation of various thermodynamic parameters such as, Gibb's free energy, entropy and enthalpy of the on-going adsorption process indicate feasibility and endothermic nature of DR12B adsorption.

  3. A multi-spectral approach to differentiate the effects of adsorbent pretreatments on the characteristics of NOM and membrane fouling.

    PubMed

    Wang, Long-Fei; Benjamin, Mark M

    2016-07-01

    Pretreatment of feed water is widely applied to mitigate NOM-induced fouling of low-pressure membranes. This research investigated the effectiveness of two pretreatment modes for NOM removal by heated aluminum oxide particles (HAOPs) and the associated reductions in membrane fouling and trihalomethane (THM) formation potential. One mode, referred to here as pre-adsorption, is the conventional process in which adsorbent particles are added to and thoroughly mixed with the feed, after which the particles are separated from the water either upstream of or by the membrane. By contrast, in the pre-deposition mode, a thin layer of adsorbent particles is deposited on a support media (which could be the membrane) prior to passing feed through the layer and the membrane. Although both pretreatment methods remove similar amounts of DOC at the same adsorbent dose, pre-deposition is superior with respect to mitigating membrane fouling and reducing DBP formation. UV and fluorescence spectroscopy and HPSEC analysis indicate that a pre-deposited adsorbent layer removes more chromophores and low apparent molecular weight (AMW) material than pre-adsorption does. Based on absorbance ratios at selected wavelengths, a pre-deposited HAOPs layer removes more aromatic moieties than aliphatic carboxyls, especially at higher HAOPs doses. In addition, pre-deposition is more effective than pre-adsorption at reducing the THM formation potential. The results provide new insights into the interactions between HAOPs and NOM molecules and shed light on the significantly different effects of different adsorbent contacting modes on the fouling potential of the pretreated water. PMID:27082692

  4. Contact dermatitis in children

    PubMed Central

    2010-01-01

    Contact dermatitis in pediatric population is a common but (previously) under recognized disease. It is usually divided into the allergic and the irritant forms. The diagnosis is usually obtained with the patch test technique after conducting a thorough medical history and careful physical examination but patch testing in infants may be particularly difficult, and false-positive reactions may occur. This study also provides an overview of the most common allergens in pediatric population and discusses various therapeutic modalities. PMID:20205907

  5. Contact stress sensor

    DOEpatents

    Kotovsky, Jack

    2014-02-11

    A method for producing a contact stress sensor that includes one or more MEMS fabricated sensor elements, where each sensor element of includes a thin non-recessed portion, a recessed portion and a pressure sensitive element adjacent to the recessed portion. An electric circuit is connected to the pressure sensitive element. The circuit includes a pressure signal circuit element configured to provide a signal upon movement of the pressure sensitive element.

  6. Contact stress sensor

    DOEpatents

    Kotovsky, Jack

    2012-02-07

    A contact stress sensor includes one or more MEMS fabricated sensor elements, where each sensor element of includes a thin non-recessed portion, a recessed portion and a pressure sensitive element adjacent to the recessed portion. An electric circuit is connected to the pressure sensitive element. The circuit includes a thermal compensator and a pressure signal circuit element configured to provide a signal upon movement of the pressure sensitive element.

  7. Fabricating electrospun cellulose nanofibre adsorbents for ion-exchange chromatography

    PubMed Central

    Dods, Stewart R.; Hardick, Oliver; Stevens, Bob; Bracewell, Daniel G.

    2015-01-01

    Protein separation is an integral step in biopharmaceutical manufacture with diffusion-limited packed bed chromatography remaining the default choice for industry. Rapid bind-elute separation using convective mass transfer media offers advantages in productivity by operating at high flowrates. Electrospun nanofibre adsorbents are a non-woven fibre matrix of high surface area and porosity previously investigated as a bioseparation medium. The effects of compression and bed layers, and subsequent heat treatment after electrospinning cellulose acetate nanofibres were investigated using diethylaminoethyl (DEAE) or carboxylate (COO) functionalisations. Transbed pressures were measured and compared by compression load, COO adsorbents were 30%, 70% and 90% higher than DEAE for compressions 1, 5 and 10 MPa, respectively, which was attributed to the swelling effect of hydrophilic COO groups. Dynamic binding capacities (DBCs) at 10% breakthrough were measured between 2000 and 12,000 CV/h (2 s and 0.3 s residence times) under normal binding conditions, and DBCs increased with reactant concentration from 4 to 12 mg BSA/mL for DEAE and from 10 to 21 mg lysozyme/mL for COO adsorbents. Comparing capacities of compression loads applied after electrospinning showed that the lowest load tested, 1 MPa, yielded the highest DBCs for DEAE and COO adsorbents at 20 mg BSA/mL and 27 mg lysozyme/mL, respectively. At 1 MPa, DBCs were the highest for the lowest flowrate tested but stabilised for flowrates above 2000 CV/h. For compression loads of 5 MPa and 10 MPa, adsorbents recorded lower DBCs than 1 MPa as a result of nanofibre packing and reduced surface area. Increasing the number of bed layers from 4 to 12 showed decreasing DBCs for both adsorbents. Tensile strengths were recorded to indicate the mechanical robustness of the adsorbent and be related to packing the nanofibre adsorbents in large scale configurations such as pleated cartridges. Compared with an

  8. Functional modular contact lens

    NASA Astrophysics Data System (ADS)

    Shum, Angela J.; Cowan, Melissa; Lähdesmäki, Ilkka; Lingley, Andrew; Otis, Brian; Parviz, Babak A.

    2009-08-01

    Tear fluid offers a potential route for non-invasive sensing of physiological parameters. Utilization of this potential depends on the ability to manufacture sensors that can be placed on the surface of the eye. A contact lens makes a natural platform for such sensors, but contact lens polymers present a challenge for sensor fabrication. This paper describes a microfabrication process for constructing sensors that can be integrated into the structure of a functional contact lens in the future. To demonstrate the capabilities of the process, an amperometric glucose sensor was fabricated on a polymer substrate. The sensor consists of platinum working and counter electrodes, as well as a region of indium-tin oxide (ITO) for glucose oxidase immobilization. An external silver-silver chloride electrode was used as the reference electrode during the characterization experiments. Sensor operation was validated by hydrogen peroxide measurements in the 10- 20 μM range and glucose measurements in the 0.125-20 mM range.

  9. Acrylate Systemic Contact Dermatitis.

    PubMed

    Sauder, Maxwell B; Pratt, Melanie D

    2015-01-01

    Acrylates, the 2012 American Contact Dermatitis Society allergen of the year, are found in a range of products including the absorbent materials within feminine hygiene pads. When fully polymerized, acrylates are nonimmunogenic; however, if not completely cured, the monomers can be potent allergens.A 28-year-old woman is presented, who had her teeth varnished with Isodan (Septodont, Saint-Maur-des-Fossés, France) containing HEMA (2-hydroxyethyl methacrylate) with no initial reaction. Approximately 1 month later, the patient developed a genital dermatitis secondary to her feminine hygiene pads. The initial reaction resolved, but 5 months later, the patient developed a systemic contact dermatitis after receiving a second varnishing.The patient was dramatically patch test positive to many acrylates. This case demonstrates a reaction to likely unpolymerized acrylates within a feminine hygiene pad, as well as broad cross-reactivity or cosensitivity to acrylates, and possibly a systemic contact dermatitis with systemic re-exposure to unpolymerized acrylates. PMID:26367207

  10. Pediatric contact dermatitis.

    PubMed

    Sharma, Vinod K; Asati, Dinesh P

    2010-01-01

    Allergic contact dermatitis (ACD) in children, until recently, was considered rare. ACD was considered as a disorder of the adult population and children were thought to be spared due to a lack of exposure to potential allergens and an immature immune system. Prevalence of ACD to even the most common allergens in children, like poison ivy and parthenium, is relatively rare as compared to adults. However, there is now growing evidence of contact sensitization of the pediatric population, and it begins right from early childhood, including 1-week-old neonates. Vaccinations, piercing, topical medicaments and cosmetics in younger patients are potential exposures for sensitization. Nickel is the most common sensitizer in almost all studies pertaining to pediatric contact dermatitis. Other common allergens reported are cobalt, fragrance mix, rubber, lanolin, thiomersol, neomycin, gold, mercapto mix, balsum of Peru and colophony. Different factors like age, sex, atopy, social and cultural practices, habit of parents and caregivers and geographic changes affect the patterns of ACD and their variable clinical presentation. Patch testing should be considered not only in children with lesions of a morphology suggestive of ACD, but in any child with dermatitis that is difficult to control. PMID:20826990

  11. Elution by Le Chatelier's principle for maximum recyclability of adsorbents: applied to polyacrylamidoxime adsorbents for extraction of uranium from seawater.

    PubMed

    Oyola, Yatsandra; Vukovic, Sinisa; Dai, Sheng

    2016-05-28

    Amidoxime-based polymer adsorbents have attracted interest within the last decade due to their high adsorption capacities for uranium and other rare earth metals from seawater. The ocean contains an approximated 4-5 billion tons of uranium and even though amidoxime-based adsorbents have demonstrated the highest uranium adsorption capacities to date, they are still economically impractical because of their limited recyclability. Typically, the adsorbed metals are eluted with a dilute acid solution that not only damages the amidoxime groups (metal adsorption sites), but is also not strong enough to remove the strongly bound vanadium, which decreases the adsorption capacity with each cycle. We resolved this challenge by incorporating Le Chatelier's principle to recycle adsorbents indefinitely. We used a solution with a high concentration of amidoxime-like chelating agents, such as hydroxylamine, to desorb nearly a 100% of adsorbed metals, including vanadium, without damaging the metal adsorption sites and preserving the high adsorption capacity. The method takes advantage of knowing the binding mode between the amidoxime ligand and the metal and mimics it with chelating agents that then in a Le Chatelier's manner removes metals by shifting to a new chemical equilibrium. For this reason the method is applicable to any ligand-metal adsorbent and it will make an impact on other extraction technologies. PMID:27117598

  12. Ceria modified activated carbon: an efficient arsenic removal adsorbent for drinking water purification

    NASA Astrophysics Data System (ADS)

    Sawana, Radha; Somasundar, Yogesh; Iyer, Venkatesh Shankar; Baruwati, Babita

    2016-03-01

    Ceria (CeO2) coated powdered activated carbon was synthesized by a single step chemical process and demonstrated to be a highly efficient adsorbent for the removal of both As(III) and As(V) from water without any pre-oxidation process. The formation of CeO2 on the surface of powdered activated carbon was confirmed by X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. The percentage of Ce in the adsorbent was confirmed to be 3.5 % by ICP-OES. The maximum removal capacity for As(III) and As(V) was found to be 10.3 and 12.2 mg/g, respectively. These values are comparable to most of the commercially available adsorbents. 80 % of the removal process was completed within 15 min of contact time in a batch process. More than 95 % removal of both As(III) and As(V) was achieved within an hour. The efficiency of removal was not affected by change in pH (5-9), salinity, hardness, organic (1-4 ppm of humic acid) and inorganic anions (sulphate, nitrate, chloride, bicarbonate and fluoride) excluding phosphate. Presence of 100 ppm phosphate reduced the removal significantly from 90 to 18 %. The equilibrium adsorption pattern of both As(III) and As(V) fitted well with the Freundlich model with R 2 values 0.99 and 0.97, respectively. The material shows reusability greater than three times in a batch process (arsenic concentration reduced below 10 ppb from 330 ppb) and a life of at least 100 L in a column study with 80 g material when tested under natural hard water (TDS 1000 ppm, pH 7.8, hardness 600 ppm as CaCO3) spiked with 330 ppb of arsenic.

  13. Bioavailability of medroxyprogesterone acetate from three oral dosage formulations.

    PubMed

    Stalker, D J; Welshman, I R; Pollock, S R

    1992-01-01

    The bioavailability of three formulations of medroxyprogesterone acetate (MPA) was assessed in 30 healthy male volunteers in a three-way, open-label, cross-over-designed trial. Each subject received one Provera 500-mg tablet, one Farlutal 500-mg tablet, and one Provera 500-mg granule packet according to a randomized schedule, with each treatment separated by a 21-day washout period. Serum MPA levels were determined using both radioimmunoassay (RIA) and high-performance liquid chromatography techniques. Based on the results of RIA analysis, Farlutal tablets produced significantly lower serum MPA concentrations compared with Provera tablets at most sampling times, resulting in statistically lower AUC0-144 for the Farlutal tablet (544 vs 768 ng.hr/ml; -29.2%). The Farlutal tablet also had a significantly lower maximum concentration than the Provera tablet (27.8 vs 47.4 ng/ml; -41.4%). However, there was no significant difference in time of maximum concentration between the tablet formulations (3.71 vs 3.41 hr), indicating that the rates of absorption of the two tablet formulations were comparable. Provera granules provided significantly higher serum MPA levels than Provera tablets at 0.5, 1, 1.5, 2, and 6 hours, and the AUC0-144 for Provera granules was higher by 5.47% (810 vs 768 ng.hr/ml). There were no differences in terminal elimination rate constants among the dosage forms. No significant adverse events were noted during the trial. The relative bioavailabilities of Provera granules and Farlutal tablets were 105% and 71.2%, respectively, compared with Provera tablets. PMID:1388093

  14. COX-2 gene dosage-dependent defects in kidney development.

    PubMed

    Slattery, Patrick; Frölich, Stefanie; Schreiber, Yannik; Nüsing, Rolf M

    2016-05-15

    Deletion of cyclooxygenase (COX)-2 causes impairment of kidney development, including hypothrophic glomeruli and cortical thinning. A critical role for COX-2 is seen 4-8 days postnatally. The present study was aimed at answering whether different COX-2 gene dosage and partial pharmacological COX-2 inhibition impairs kidney development. We studied kidney development in COX-2(+/+), COX-2(+/-), and COX-2(-/-) mice as well as in C57Bl6 mice treated postnatally with low (5 mg·kg(-1)·day(-1)) and high (10 mg·kg(-1)·day(-1)) doses of the selective COX-2 inhibitor SC-236. COX-2(+/-) mice exhibit impaired kidney development leading to reduced glomerular size but, in contrast to COX-2(-/-) mice, only marginal cortical thinning. Moreover, in COX-2(+/-) and COX-2(-/-) kidneys, juxtamedullary glomeruli, which develop in the very early stages of nephrogenesis, also showed a size reduction. In COX-2(+/-) kidneys at the age of 8 days, we observed significantly less expression of COX-2 mRNA and protein and less PGE2 and PGI2 synthetic activity compared with COX-2(+/+) kidneys. The renal defects in COX-2(-/-) and COX-2(+/-) kidneys could be mimicked by high and low doses of SC-236, respectively. In aged COX-2(+/-) kidneys, glomerulosclerosis was observed; however, in contrast to COX-2(-/-) kidneys, periglomerular fibrosis was absent. COX-2(+/-) mice showed signs of kidney insufficiency, demonstrated by enhanced serum creatinine levels, quite similar to COX-2(-/-) mice, but, in contrast, serum urea remained at the control level. In summary, function of both COX-2 gene alleles is absolutely necessary to ensure physiological development of the mouse kidney. Loss of one copy of the COX-2 gene or partial COX-2 inhibition is associated with distinct renal damage and reduced kidney function. PMID:26984955

  15. The importance of MDR1 gene polymorphisms for tacrolimus dosage.

    PubMed

    Kravljaca, Milica; Perovic, Vladimir; Pravica, Vera; Brkovic, Voin; Milinkovic, Marija; Lausevic, Mirjana; Naumovic, Radomir

    2016-02-15

    Polymorphisms of the multi drug resistance (MDR1) gene cause variability in P-glycoprotein mediated metabolism of tacrolimus. The aim of this study was to examine the relationship between MDR1 gene single nucleotide polymorphisms (SNPs) and their haplotypes with dosage of tacrolimus in kidney transplant recipients who were cytochrome (CYP) 3A5*3 homozygotes. This study included 91 kidney transplant recipients followed two years after transplantation. Detection and analysis of MDR1 gene polymorphisms in positions C1236T, G2677T/A and C3435T were performed using PCR method. Patients with variant alleles for SNPs G2677T/A and C3435T required higher doses of tacrolimus and had a lower level/dose (L/D) ratio than patients with wild alleles or heterozygotes. That difference was the most obvious for SNP G2677T/A where TT homozygotes required significantly higher doses of tacrolimus during whole follow-up. Their L/D was significantly lower in the first month after transplantation. Recipients with CTT/TTT haplotype also had lower L/D than those with CGC/TTT and CGC/CGC, significantly in the 10th and 20th days after transplantation respectively (p<0.05). Our results demonstrate that TT homozygotes at positions G2677T/A and C3435T required a higher tacrolimus dose than those with wild alleles or heterozygotes. It may be helpful in the prevention of tacrolimus nephrotoxicity early after transplantation. PMID:26705892

  16. Cystic gene dosage influences kidney lesions after nephron reduction.

    PubMed

    Le Corre, Stéphanie; Viau, Amandine; Burtin, Martine; El-Karoui, Khalil; Cnops, Yvette; Terryn, Sara; Debaix, Huguette; Bérissi, Sophie; Gubler, Marie-Claire; Devuyst, Olivier; Terzi, Fabiola

    2015-01-01

    Cystic kidney disease is characterized by the progressive development of multiple fluid-filled cysts. Cysts can be acquired, or they may appear during development or in postnatal life due to specific gene defects and lead to renal failure. The most frequent form of this disease is the inherited polycystic kidney disease (PKD). Experimental models of PKD showed that an increase of cellular proliferation and apoptosis as well as defects in apico-basal and planar cell polarity or cilia play a critical role in cyst development. However, little is known about the mechanisms and the mediators involved in acquired cystic kidney diseases (ACKD). In this study, we used the nephron reduction as a model to study the mechanisms underlying cyst development in ACKD. We found that tubular dilations after nephron reduction recapitulated most of the morphological features of ACKD. The development of tubular dilations was associated with a dramatic increase of cell proliferation. In contrast, the apico-basal polarity and cilia did not seem to be affected. Interestingly, polycystin 1 and fibrocystin were markedly increased and polycystin 2 was decreased in cells lining the dilated tubules, whereas the expression of several other cystic genes did not change. More importantly, Pkd1 haploinsufficiency accelerated the development of tubular dilations after nephron reduction, a phenotype that was associated to a further increase of cell proliferation. These data were relevant to humans ACKD, as cystic genes expression and the rate of cell proliferation were also increased. In conclusion, our study suggests that the nephron reduction can be considered a suitable model to study ACKD and that dosage of genes involved in PKD is also important in ACKD. PMID:25531116

  17. Dual contact pogo pin assembly

    DOEpatents

    Hatch, Stephen McGarry

    2016-06-21

    A contact assembly includes a base and a pair of electrical contacts supported by the base. A first end of the first electrical contact corresponds to a first end of the base and is configured to engage a first external conductive circuit element. A first end of the second electrical contact also corresponds to the first end of the base and is configured to engage a second external conductive circuit element. The first contact and the second contact are electrically isolated from one another and configured to compress when engaging an external connector element. The base includes an aperture positioned on a second end of the base outboard of a second end of the first and second electrical contacts. The aperture presents a narrowing shape with a wide mouth distal the electrical contacts and a narrow internal through-hole proximate the electrical contacts.

  18. Dual contact pogo pin assembly

    DOEpatents

    Hatch, Stephen McGarry

    2015-01-20

    A contact assembly includes a base and a pair of electrical contacts supported by the base. A first end of the first electrical contact corresponds to a first end of the base and is configured to engage a first external conductive circuit element. A first end of the second electrical contact also corresponds to the first end of the base and is configured to engage a second external conductive circuit element. The first contact and the second contact are electrically isolated from one another and configured to compress when engaging an external connector element. The base includes an aperture positioned on a second end of the base outboard of a second end of the first and second electrical contacts. The aperture presents a narrowing shape with a wide mouth distal the electrical contacts and a narrow internal through-hole proximate the electrical contacts.

  19. Positive frequency shifts observed upon adsorbing micron-sized solid objects to a quartz crystal microbalance from the liquid phase.

    PubMed

    Pomorska, Agata; Shchukin, Dmitry; Hammond, Richard; Cooper, Matthew A; Grundmeier, Guido; Johannsmann, Diethelm

    2010-03-15

    By specifically binding derivatized colloidal particles and physisorbing nonderivatized particles to the surface of a quartz crystal microbalance (QCM), we have observed positive shifts of frequency, Deltaf, in contrast to the negative frequency shifts typically found in adsorption experiments. Evidently, the Sauerbrey relation does not apply to this situation. A comparison of frequencies shifts and bandwidths on different overtones reveals a coupled resonance: at low overtones, Deltaf is negative, whereas it is positive at high overtones, with maximal resonance bandwidth observed at the crossover point. As predicted by the Dybwad model, the spheres bound to the surface form resonating systems on their own. A composite resonator is formed, consisting of a large crystal with resonance frequency omega and the adsorbed spheres with resonance frequency omega(S). In the case in which the resonance frequency of the small spheres (firmly attached to crystal), omega(S), is higher than the resonance frequency of the crystal, omega, Deltaf of the composite system is negative (leading to the Sauerbrey limit). In the opposite limit (that is, in the case of large adsorbed particles bound to the sensor surface via a sufficiently weak bridge) Deltaf is positive. Such a behavior is known from sphere-plate contacts in the dry state. Finite element calculation demonstrates that this phenomena is also plausible in liquid phase media, with Deltaf critically dependent on the strength of the sphere-plate contact. Operated in this mode, the QCM most likely probes the contact strength, rather than the mass of the particle. PMID:20166672

  20. Softgels: consumer perceptions and market impact relative to other oral dosage forms.

    PubMed

    Jones, W J; Francis, J J

    2000-01-01

    Softgels, which contain a liquid formulation of a drug, often provide clinical benefit over other solid oral dosage forms and may represent an attractive alternative to them. A consumer preference survey of softgels versus other solid forms investigated four areas: (1) identification of various dosage forms; (2) perception of therapeutic benefit (easiest to swallow, faster-acting, work longer); (3) impact of individual product characteristics on overall product selection; and (4) market impact in terms of premiums consumers would pay on the basis of dosage form. The 300 survey participants strongly preferred clear softgels over other dosage forms in virtually every area. Softgels were perceived as easy to swallow and fast-acting, with a duration of action second only to that of a two-piece capsule. Overall preference was driven by ease of swallowing, and softgels were rated first by the majority of respondents. Consumers would be interested in various products if these were available as softgels rather than in their current oral dosage forms and may be willing to pay a premium for softgel products. This survey confirms consumer preferences for particular dosage forms and for softgels over other solid forms. Pharmaceutical scientists and marketers should consider softgels as alternative dosage forms when developing new compounds or considering life-cycle management of existing products. PMID:11186141

  1. Dosage Effects of a Drosophila Sodium Channel Gene on Behavior and Axonal Excitability

    PubMed Central

    Stern, M.; Kreber, R.; Ganetzky, B.

    1990-01-01

    The effects of para mutations on behavior and axonal excitability in Drosophila suggested that para specifically affects sodium channels. This hypothesis was confirmed by molecular analysis of the para locus, which demonstrates that the encoded para product is a sodium channel polypeptide. Here we characterize the effects of altered para(+) dosage on behavior and axonal excitability, both in an otherwise wild-type background and in combination with two other mutations: nap(ts), which also affects sodium channels, and Sh(KS133), which specifically affects potassium channels. Whereas it was previously shown that decreased dosage of para(+) is unconditionally lethal in a .nap(ts) background, we find that increased dosage of para(+) suppresses nap(ts). Similarly, we find that para hypomorphs or decreased dosage of para(+) suppresses Sh(KS133), whereas increased dosage of para(+) enhances Sh(KS133). The electrophysiological basis for these effects is investigated. Other genes in Drosophila that have sequence homology to sodium channels do not show such dosage effects, which suggests that the para(+) product has a function distinct from that of other putative Drosophila sodium channel genes. We conclude that the number of sodium channels present in at least some Drosophila neurons can be affected by changes in para(+) gene dosage, and that the level of para(+) expression can strongly influence neuronal excitability. PMID:2155153

  2. Theoretical study of line and boundary tension in adsorbed colloid-polymer mixtures.

    PubMed

    Koning, Jesper; Vandecan, Yves; Indekeu, Joseph

    2014-07-28

    An extended theoretical study of interface potentials in adsorbed colloid-polymer mixtures is performed. To describe the colloid-polymer mixture near a hard wall, a simple Cahn-Nakanishi-Fisher free-energy functional is used. The bulk phase behaviour and the substrate-adsorbate interaction are modelled by the free-volume theory for ideal polymers with polymer-to-colloid size ratios q = 0.6 and q = 1. The interface potentials are constructed with help from a Fisher-Jin crossing constraint. By manipulating the crossing density, a complete interface potential can be obtained from natural, single-crossing, profiles. The line tension in the partial wetting regime and the boundary tension along prewetting are computed from the interface potentials. The line tensions are of either sign, and descending with increasing contact angle. The line tension takes a positive value of 10(-14)-10(-12) N near a first-order wetting transition, passes through zero and decreases to minus 10(-14)-10(-12) N away from the first-order transition. The calculations of the boundary tension along prewetting yield values increasing from zero at the prewetting critical point up to the value of the line tension at first-order wetting. PMID:25084953

  3. Theoretical study of line and boundary tension in adsorbed colloid-polymer mixtures

    NASA Astrophysics Data System (ADS)

    Koning, Jesper; Vandecan, Yves; Indekeu, Joseph

    2014-07-01

    An extended theoretical study of interface potentials in adsorbed colloid-polymer mixtures is performed. To describe the colloid-polymer mixture near a hard wall, a simple Cahn-Nakanishi-Fisher free-energy functional is used. The bulk phase behaviour and the substrate-adsorbate interaction are modelled by the free-volume theory for ideal polymers with polymer-to-colloid size ratios q = 0.6 and q = 1. The interface potentials are constructed with help from a Fisher-Jin crossing constraint. By manipulating the crossing density, a complete interface potential can be obtained from natural, single-crossing, profiles. The line tension in the partial wetting regime and the boundary tension along prewetting are computed from the interface potentials. The line tensions are of either sign, and descending with increasing contact angle. The line tension takes a positive value of 10-14-10-12 N near a first-order wetting transition, passes through zero and decreases to minus 10-14-10-12 N away from the first-order transition. The calculations of the boundary tension along prewetting yield values increasing from zero at the prewetting critical point up to the value of the line tension at first-order wetting.

  4. Cadmium telluride nanoparticles loaded on activated carbon as adsorbent for removal of sunset yellow.

    PubMed

    Ghaedi, M; Hekmati Jah, A; Khodadoust, S; Sahraei, R; Daneshfar, A; Mihandoost, A; Purkait, M K

    2012-05-01

    Adsorption is a promising technique for decolorization of effluents of textile dyeing industries but its application is limited due to requirement of high amounts of adsorbent required. The objective of this study was to assess the potential of cadmium telluride nanoparticles loaded onto activated carbon (CdTN-AC) for the removal of sunset yellow (SY) dye from aqueous solution. Adsorption studies were conducted in a batch mode varying solution pH, contact time, initial dye concentration, CdTN-AC dose, and temperature. In order to investigate the efficiency of SY adsorption on CdTN-AC, pseudo-first-order, pseudo-second-order, Elovich, and intra-particle diffusion kinetic models were studied. It was observed that the pseudo-second-order kinetic model fits better than other kinetic models with good correlation coefficient. Equilibrium data were fitted to the Langmuir model. Thermodynamic parameters such as enthalpy, entropy, activation energy, and sticking probability were also calculated. It was found that the sorption of SY onto CdTN-AC was spontaneous and endothermic in nature. The proposed adsorbent is applicable for SY removal from waste of real effluents including pea-shooter, orange drink and jelly banana with efficiency more than 97%. PMID:22306446

  5. Cadmium telluride nanoparticles loaded on activated carbon as adsorbent for removal of sunset yellow

    NASA Astrophysics Data System (ADS)

    Ghaedi, M.; Hekmati Jah, A.; Khodadoust, S.; Sahraei, R.; Daneshfar, A.; Mihandoost, A.; Purkait, M. K.

    2012-05-01

    Adsorption is a promising technique for decolorization of effluents of textile dyeing industries but its application is limited due to requirement of high amounts of adsorbent required. The objective of this study was to assess the potential of cadmium telluride nanoparticles loaded onto activated carbon (CdTN-AC) for the removal of sunset yellow (SY) dye from aqueous solution. Adsorption studies were conducted in a batch mode varying solution pH, contact time, initial dye concentration, CdTN-AC dose, and temperature. In order to investigate the efficiency of SY adsorption on CdTN-AC, pseudo-first-order, pseudo-second-order, Elovich, and intra-particle diffusion kinetic models were studied. It was observed that the pseudo-second-order kinetic model fits better than other kinetic models with good correlation coefficient. Equilibrium data were fitted to the Langmuir model. Thermodynamic parameters such as enthalpy, entropy, activation energy, and sticking probability were also calculated. It was found that the sorption of SY onto CdTN-AC was spontaneous and endothermic in nature. The proposed adsorbent is applicable for SY removal from waste of real effluents including pea-shooter, orange drink and jelly banana with efficiency more than 97%.

  6. A comparison of adsorbed and grafted fibronectin coatings under static and dynamic conditions.

    PubMed

    Montaño-Machado, Vanessa; Hugoni, Ludivine; Díaz-Rodríguez, Sergio; Tolouei, Ranna; Chevallier, Pascale; Pauthe, Emmanuel; Mantovani, Diego

    2016-09-21

    Coatings for medical devices are expected to improve their surface biocompatibility mainly by being bioactive, i.e. stimulating healing-oriented interactions with living cells, tissues and organs. In particular, for stent applications, coatings are often designed to enhance the endothelialization process. The coating strategy will be primarily responsible for the interfacial properties between the substrate and the coating, which must show high stability. Therefore, the present work aims at comparing the stability of adsorbed and grafted fibronectin, a protein well-known to promote endothelialization. Fibronectin coatings were deposited on fluorocarbon films generated by a plasma-based process on stainless steel substrates. Then, deformation tests were performed in order to simulate the stenting procedure and stability tests were completed under static and under-flow conditions. Coatings were characterized by XPS, AFM, water contact angle, immunostaining and ToF-SIMS analyses. The results show higher stability for the grafted coatings; indeed, the integrity of the protein simply adsorbed was strongly compromised especially after under-flow tests. Both coatings exhibited similar behavior after deformation and static tests. These results clearly show the impact of the coating strategy on the overall stability of the coatings as well as the importance of under-flow investigations. PMID:27546569

  7. Process development for removal of substituted phenol by carbonaceous adsorbent obtained from fertilizer waste

    SciTech Connect

    Srivastava, S.K.; Mohan, D.; Tyagi, R.; Pal, N.

    1997-09-01

    Waste slurry, generated in local fertilizer plants, is converted into a cheap carbonaceous material. The product so obtained has been characterized and utilized for the removal of 2,4-dinitrophenol (DNP). The removal of DNP is 100% weight-to-weight (w/w) at low concentrations, while it is 80% w/w at higher concentrations. Several factors affecting the removal of DNP from water (e.g., particle size distribution, solution pH, contact time, loading of DNP on the adsorbent, etc.) have been studied at optimum pH (4.0). Both batch and column studies were performed. The adsorption capacities, adsorption rates, and break-through curves are used to optimize the contactors and identify design correlations. Some feasibility experiments have been performed, with an aim to recover DNP and chemical regeneration of the spent column. It is observed that 60 mL of 5% w/w NaOH is sufficient for almost complete desorption of DNP (loaded 57.5 mg, desorbed 55.2 mg). After regeneration with 1M HNO{sub 3}, the sorption capacity of the column is almost the same as that of virgin adsorbent material.

  8. Novel simulated moving-bed adsorber for the fractionation of gas mixtures.

    PubMed

    Rao, D P; Sivakumar, S V; Mandal, Susmita; Kota, Sridevi; Ramaprasad, B S G

    2005-03-25

    The separation of propylene-propane mixture is an energy intensive operation commercially practiced using cryogenic distillation. The separation by pressure swing adsorption has been studied as an alternative. A fixed-bed pressure swing adsorption yields the heavy component as a pure product. The product recovery and the productivity are not high. In a moving-bed process, because of the counter-current solid-gas contact, the separation achieved is similar to that of the fractionation by distillation. Although the moving-bed operation offers the upper limit for the performance of a cyclic adsorptive process, due to mechanical complexities in the handling of solids the 'simulated' moving-bed is preferred. By moving the inlet and outlet ports of streams located along the length of the bed, a moving-bed process can be realized in a fixed bed. We describe here a 'moving-port' system which permits injection or withdrawal of the fluid along the axial direction in a fixed bed. A fixed bed embedded with the moving-port systems emulates a simulated moving-bed adsorber. The proposed adsorber can fractionate a binary gas mixture into two product streams with high purities. It is similar to the Sorbex process of UOP but does not have the eluent as an additional separating agent. A parametric study indicates that high purity products and a higher productivity by an order of magnitude can be achieved with simulated moving-beds compared to the fixed beds. PMID:15844493

  9. Adsorbed and near surface structure of ionic liquids at a solid interface.

    PubMed

    Segura, Juan José; Elbourne, Aaron; Wanless, Erica J; Warr, Gregory G; Voïtchovsky, Kislon; Atkin, Rob

    2013-03-01

    The structure of solid-ionic liquid (IL) interfaces has been characterised with unprecedented clarity by employing a range of atomic force microscopy (AFM) imaging techniques and tip pressures appropriate for the system under study. Soft contact and amplitude-modulation (AM) AFM imaging have been used to elucidate the lateral structure of ILs adsorbed onto mica, and in the near surface ion layers. Data is presented for ethylammonium nitrate (EAN) and 1-ethyl-3-methylimidazolium bis(trifluoro-methylsulfonyl)imide (EMIm TFSI). Whereas EAN is a protic IL that forms a nanostructured sponge phase in the bulk, EMIm TFSI is aprotic and has weak (or absent) bulk association structure. Comparison of results obtained for the two liquids elucidates how the strength of bulk liquid morphology effects lateral organisation at the surface, and any effect of IL class, i.e. protic versus aprotic. Imaging reveals EAN self assembles at the solid surface in a worm-like morphology, whereas EMIm cations adsorb in a more isolated fashion, but still in rows templated by the mica surface. To the authors' knowledge, the wormlike structures present at the EAN-mica interface are the smallest self-assembled aggregates ever imaged on a solid surface. PMID:23361257

  10. Fast removal of copper ions from aqueous solution using an eco-friendly fibrous adsorbent.

    PubMed

    Niu, Yaolan; Ying, Diwen; Li, Kan; Wang, Yalin; Jia, Jinping

    2016-10-01

    Functional PET fiber (PET-AA-CS) was prepared by oxygen-plasma pretreatment and grafting of acrylic acid (AA) and low-molecular-weight chitosan (LMCS) on the polyethylene glycol terephthalate (PET) substrate. This adsorbent was targeted for quick removal of metal ion in river pollutions with an easy recycling of the fiber after emergency processing. The fabricated PET-AA-CS was characterized by the scanning electron microscope (SEM), contact angle, fourier transform infrared (FTIR) spectra and X-ray photoelectron spectroscopy (XPS) to look into its morphology, surface functional groups, and adsorption mechanism of copper ions from the aqueous solution. The overall adsorption process of copper ions on the PET-AA-CS was pH-dependent with an optimal pH value of 5.0, at which a maximum capacity of 68.97 mg g(-1) was obtained. The result of fitting also shows that adsorption process follows the Langmuir isotherm and pseudo-second-order model. Moreover, the material shows good stability during 5 cycles of adsorption and desorption, and also shows no significant effect of co-existing ions including Ca(2+), Mg(2+), K(+), Cl(-), and et al. In general, PET-AA-CS developed in this study shows significant benefit of eco-friend and cost-efficiency for fast removal of copper ions in potential river metal pollutions comparing with traditional adsorbents. PMID:27470942

  11. Measuring the specific contact resistance of contacts to semiconductor nanowires

    NASA Astrophysics Data System (ADS)

    Mohney, S. E.; Wang, Y.; Cabassi, M. A.; Lew, K. K.; Dey, S.; Redwing, J. M.; Mayer, T. S.

    2005-02-01

    Ohmic contacts to semiconductor nanowires are essential components of many new nanoscale electronic devices. Equations for extracting specific contact resistance (or contact resistivity) from several different test structures have been developed by modeling the metal/semiconductor contact as a transmission line, leading to the development of equations analogous to those used for planar contacts. The advantages and disadvantages of various test structures are discussed. To fabricate test structures using a convenient four-point approach, silicon nanowires have been aligned using field-assisted assembly and contacts fabricated. Finally, specific contact resistances near 5 × 10 -4 Ω cm 2 have been measured for Ti/Au contacts to p-type Si nanowires with diameters of 78 and 104 nm.

  12. Stability considerations in liquid dosage forms extemporaneously prepared from commercially available products.

    PubMed

    Glass, Beverley D; Haywood, Alison

    2006-01-01

    The pharmacist, both in community and hospital pharmacy practice, is often challenged with the preparation of a liquid dosage form not available commercially for paediatric patients, those adults unable to swallow tablets or capsules and patients who must receive medications via nasogastric or gastrostomy tubes. Recognising the lack of information available to healthcare professionals, a general discussion of the various parameters that may be modified in preparing these dosage forms and a tabulated summary of the dosage forms presented in the literature is described, which, although not exhaustive, will provide information on the formulation and stability of the most commonly prepared extemporaneous liquid dosage forms. An extensive survey of the literature and investigation of 83 liquid dosage forms revealed that stability considerations were of concern for only 7.2% of these liquid dosage forms, extemporaneously prepared from the following commercially available products: captopril, hydralazine hydrochloride, isoniazid, levothyroxine sodium, phenoxybenzamine hydrochloride and tetracycline hydrochloride. Inclusion of the antioxidant, sodium ascorbate in the liquid dosage form for captopril resulted in improved stability at 4 degrees C. Hydralazine hydrochloride, isoniazid and phenoxybenzamine hydrochloride were adversely affected due to interactions with excipients in the formulation, while the effect of the preservative in lowering the pH in a levothyroxine sodium mixture resulted in decreased stability. Interestingly, the instability in these formulations is primarily due to interactions between the drug substance and the excipients rather than degradation of the active pharmaceutical ingredient by standard routes such as oxidation, hydrolysis, photolysis or thermolysis. This low percentage however illustrates the low risk associated with these dosage forms investigated. It may be concluded that when considering the safety and efficacy of liquid dosage forms

  13. Partial Model of Insulator/Insulator Contact Charging

    NASA Technical Reports Server (NTRS)

    Hogue, Michael; Calle, C. I.; Buhler, C. R.; Mucciolo, E. R.

    2005-01-01

    Two papers present a two-phase equilibrium model that partly explains insulator/ insulator contact charging. In this model, a vapor of ions within a gas is in equilibrium with a submonolayer of ions of the same species that have been adsorbed on the surface of an insulator. The surface is modeled as having localized states, each with a certain energy of adsorption for an ion. In an earlier version of the model described in the first paper, the ions do not interact with each other. Using the grand canonical ensemble, the chemical potentials of both vapor and absorbed phases are derived and equated to determine the vapor pressure. If a charge is assigned to the vapor particles (in particular, if single ionization is assumed), then the surface charge density associated with adsorbed ions can be calculated as a function of pressure. In a later version of the model presented in the second paper, the submodel of the vapor phase is extended to include electrostatic interactions between vapor ions and adsorbed ones as well as the screening effect, at a given distance from the surface, of ions closer to the surface. Theoretical values of this model closely match preliminary experimental data on the discharge of insulators as a function of pressure.

  14. Mesoporous magnetic secondary nanostructures as versatile adsorbent for efficient scavenging of heavy metals

    PubMed Central

    Bhattacharya, Kakoli; Parasar, Devaborniny; Mondal, Bholanath; Deb, Pritam

    2015-01-01

    Porous magnetic secondary nanostructures exhibit high surface area because of the presence of plentiful interparticle spaces or pores. Mesoporous Fe3O4 secondary nanostructures (MFSNs) have been studied here as versatile adsorbent for heavy metal scavenging. The porosity combined with magnetic functionality of the secondary nanostructures has facilitated efficient heavy metal (As, Cu and Cd) remediation from water solution within a short period of contact time. It is because of the larger surface area of MFSNs due to the porous network in addition to primary nanostructures which provides abundant adsorption sites facilitating high adsorption of the heavy metal ions. The brilliance of adsorption property of MFSNs has been realized through comprehensive adsorption studies and detailed kinetics. Due to their larger dimension, MFSNs help in overcoming the Brownian motion which facilitates easy separation of the metal ion sorbed secondary nanostructures and also do not get drained out during filtration, thus providing pure water. PMID:26602613

  15. Mesoporous magnetic secondary nanostructures as versatile adsorbent for efficient scavenging of heavy metals

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Kakoli; Parasar, Devaborniny; Mondal, Bholanath; Deb, Pritam

    2015-11-01

    Porous magnetic secondary nanostructures exhibit high surface area because of the presence of plentiful interparticle spaces or pores. Mesoporous Fe3O4 secondary nanostructures (MFSNs) have been studied here as versatile adsorbent for heavy metal scavenging. The porosity combined with magnetic functionality of the secondary nanostructures has facilitated efficient heavy metal (As, Cu and Cd) remediation from water solution within a short period of contact time. It is because of the larger surface area of MFSNs due to the porous network in addition to primary nanostructures which provides abundant adsorption sites facilitating high adsorption of the heavy metal ions. The brilliance of adsorption property of MFSNs has been realized through comprehensive adsorption studies and detailed kinetics. Due to their larger dimension, MFSNs help in overcoming the Brownian motion which facilitates easy separation of the metal ion sorbed secondary nanostructures and also do not get drained out during filtration, thus providing pure water.

  16. Adsorption of arsenate from aqueous solution by rice husk-based adsorbent

    NASA Astrophysics Data System (ADS)

    Khan, Taimur; Chaudhuri, Malay

    2013-06-01

    Rice husk-based adsorbent (RHBA) was prepared by burning rice husk in a muffle furnace at 400°C for 4 h and adsorption of arsenate by the RHBA from aqueous solution was examined. Batch adsorption test showed that extent of arsenate adsorption depended on contact time and pH. Equilibrium adsorption was attained in 60 min, with maximum adsorption occurring at pH 7. Equilibrium adsorption data were well described by the Freundlich isotherm model. Freundlich constants Kf and 1/n were 3.62 and 2, respectively. The RHBA is effective in the adsorption of arsenate from water and is a potentially suitable filter medium for removing arsenate from groundwater at wells or in households.

  17. Decomposition products of N, N'-disalicylidene-1,2-propanediamine adsorbed on 304 stainless steel

    NASA Astrophysics Data System (ADS)

    Chusuei, C. C.; Morris, R. E.; Schreifels, J. A.

    1999-12-01

    The compound, N, N'-disalicylidene-1,2-propanediamine, is commonly added to jet fuels to counteract the catalysis of thermally induced autoxidation by certain dissolved metals. The behavior of the metal deactivator additive (MDA) in thermally stressed jet fuel has raised questions on whether it decomposes after coming into contact with hot metal surfaces within the aircraft fuel system. Temperature programmed desorption (TPD) was performed to detect decomposition products of MDA on the 304SS surface. A method of scanning a relatively large mass range during desorption was developed to acquire 3-dimensional contour TPD (CTPD) plots of adsorbed species on the surface. Compounds with molecular masses of 107, 133, 232 and 290 were detected and their structures proposed. Conventional TPD spectra of selected molecular masses were then taken as a function of exposure. Mechanistic pathways for decomposition of MDA and formation of new compounds on the surfaces are proposed.

  18. Probing interactions between TiO 2 photocatalyst and adsorbing species using quartz crystal microbalance

    NASA Astrophysics Data System (ADS)

    Morand, R.; Noworyta, K.; Augustynski, J.

    2002-10-01

    Photoactivity of nanocrystalline TiO 2 films is shown to be strongly affected by the presence in aqueous solution of salicylic acid, known to form Ti(IV)salicylate surface complexes. In particular, the photooxidation of methanol - an effective hole scavenger - at TiO 2 appears to be in part, or even completely inhibited by the additions of increasing amounts of salicylic acid. The chemisorption of salicylic and also phthalic acid on TiO 2 was followed using quartz crystal microbalance, QCM. The observed resonant frequency changes of the quartz crystal bearing TiO 2 films, accompanying increasing additions of the benzoic acids to the contacting solutions, indicate large displacement of water as a consequence of the adsorbent-imparted hydrophobicity of the interface.

  19. Solid particles adsorbed on capillary-bridge-shaped fluid polystyrene surfaces.

    PubMed

    McEnnis, Kathleen; Dinsmore, Anthony D; Russell, Thomas P

    2015-05-19

    Particles adsorbed on microscopic polystyrene (PS) capillary bridge surfaces were observed to investigate their motion under capillary forces arising from a nonuniform shape. Capillary bridges were created by placing thin PS films, heated above the glass transition temperature (Tg), between two electrodes with an air gap between the surface of the PS and the upper electrode. Silica particles, 100 nm in diameter, were placed on the surface of the PS capillary bridges, and the sample was heated above the Tg of PS to enable particle motion. Samples were cooled to below Tg, and the locations of the particles were observed using scanning electron microscopy. The particles did not preferentially locate around the center of the capillary bridge, as predicted by others, but instead segregated to the edges. These results indicate that the forces driving particles to the three-phase contact line (air/PS/electrode surface) are greater than those locating particles around the center. PMID:25938879

  20. Mesoporous magnetic secondary nanostructures as versatile adsorbent for efficient scavenging of heavy metals.

    PubMed

    Bhattacharya, Kakoli; Parasar, Devaborniny; Mondal, Bholanath; Deb, Pritam

    2015-01-01

    Porous magnetic secondary nanostructures exhibit high surface area because of the presence of plentiful interparticle spaces or pores. Mesoporous Fe3O4 secondary nanostructures (MFSNs) have been studied here as versatile adsorbent for heavy metal scavenging. The porosity combined with magnetic functionality of the secondary nanostructures has facilitated efficient heavy metal (As, Cu and Cd) remediation from water solution within a short period of contact time. It is because of the larger surface area of MFSNs due to the porous network in addition to primary nanostructures which provides abundant adsorption sites facilitating high adsorption of the heavy metal ions. The brilliance of adsorption property of MFSNs has been realized through comprehensive adsorption studies and detailed kinetics. Due to their larger dimension, MFSNs help in overcoming the Brownian motion which facilitates easy separation of the metal ion sorbed secondary nanostructures and also do not get drained out during filtration, thus providing pure water. PMID:26602613

  1. Sex Chromosome Dosage Compensation in Heliconius Butterflies: Global yet Still Incomplete?

    PubMed Central

    Walters, James R.; Hardcastle, Thomas J.; Jiggins, Chris D.

    2015-01-01

    The evolution of heterogametic sex chromosomes is often—but not always—accompanied by the evolution of dosage compensating mechanisms that mitigate the impact of sex-specific gene dosage on levels of gene expression. One emerging view of this process is that such mechanisms may only evolve in male-heterogametic (XY) species but not in female-heterogametic (ZW) species, which will consequently exhibit “incomplete” sex chromosome dosage compensation. However, recent results suggest that at least some Lepidoptera (moths and butterflies) may prove to be an exception to this prediction. Studies in bombycoid moths indicate the presence of a chromosome-wide epigenetic mechanism that effectively balances Z chromosome gene expression between the sexes by reducing Z-linked expression in males. In contrast, strong sex chromosome dosage effects without any reduction in male Z-linked expression were previously reported in a pyralid moth, suggesting a lack of any such dosage compensating mechanism. Here we report an analysis of sex chromosome dosage compensation in Heliconius butterflies, sampling multiple individuals for several different adult tissues (head, abdomen, leg, mouth, and antennae). Methodologically, we introduce a novel application of linear mixed-effects models to assess dosage compensation, offering a unified statistical framework that can estimate effects specific to chromosome, to sex, and their interactions (i.e., a dosage effect). Our results show substantially reduced Z-linked expression relative to autosomes in both sexes, as previously observed in bombycoid moths. This observation is consistent with an increasing body of evidence that some lepidopteran species possess an epigenetic dosage compensating mechanism that reduces Z chromosome expression in males to levels comparable with females. However, this mechanism appears to be imperfect in Heliconius, resulting in a modest dosage effect that produces an average 5–20% increase in male expression

  2. Conservation and de novo acquisition of dosage compensation on newly evolved sex chromosomes in Drosophila

    PubMed Central

    Alekseyenko, Artyom A.; Ellison, Christopher E.; Gorchakov, Andrey A.; Zhou, Qi; Kaiser, Vera B.; Toda, Nick; Walton, Zaak; Peng, Shouyong; Park, Peter J.; Bachtrog, Doris; Kuroda, Mitzi I.

    2013-01-01

    Dosage compensation has arisen in response to the evolution of distinct male (XY) and female (XX) karyotypes. In Drosophila melanogaster, the MSL complex increases male X transcription approximately twofold. X-specific targeting is thought to occur through sequence-dependent binding to chromatin entry sites (CESs), followed by spreading in cis to active genes. We tested this model by asking how newly evolving sex chromosome arms in Drosophila miranda acquired dosage compensation. We found evidence for the creation of new CESs, with the analogous sequence and spacing as in D. melanogaster, providing strong support for the spreading model in the establishment of dosage compensation. PMID:23630075

  3. Vibrational Studies of Adsorbate-Induced Reconstruction on Molybdenum Surfaces.

    NASA Astrophysics Data System (ADS)

    Lopinski, Gregory Peter

    Adsorbate-induced rearrangement of the substrate structure strongly modifies the adsorbate-substrate and adsorbate-adsorbate interactions, leading to the complex behavior observed in many chemisorption systems. In this thesis the H/Mo(211), O/Mo(211) and Na/Mo(100) systems have been studied using high resolution electron energy loss spectroscopy (HREELS) to observe vibrations of the adsorbed atoms. The vibrational data is correlated with observations of the long-range order probed by LEED as well as the work function changes induced by adsorption. Adsorbate -induced substrate reconstruction plays an important role in all three of these systems. Studies of the coadsorption systems O+H/Mo(211) and Na+O/Mo(100) indicate how these effects can influence interactions between adsorbates. For H/Mo(211), above 1ML a (1 x 1) to (1 x 2) transition is observed and attributed to modification of the substrate periodicity. Below 1ML, H atoms are bridge bonded and induce local distortions of the substrate. The transition to the (1 x 2) phase involves the ordering of these displacements and occupation of three-fold sites partially populated by conversion of the bridge bonded species. This conversion accounts for the sawtooth-like coverage dependence of the work function. The structural model proposed for this system is also supported by the desorption parameters and partial molar entropy extracted from adsorption isobars. Oxygen adsorption on Mo(211) involves the occupation of multiple binding sites, with both the long-range order and the local geometry of the adsorbate phases strongly temperature dependent. Coadsorption of low coverages of oxygen and hydrogen leads to segregation of the two adsorbates which can be understood in terms of a substrate-mediated repulsive interaction between O and H. For Na/Mo(100), the frequency of the Na-Mo symmetric stretch mode does not shift with coverage although the mode intensity is strongly coverage dependent. The absence of a frequency shift

  4. [DSC and FTIR study of adsorbed lysozyme on hydrophobic surface].

    PubMed

    Lei, Zu-meng; Geng, Xin-peng; Dai, Li; Geng, Xin-du

    2008-09-01

    During a process of hen egg white lysozyme adsorption and folding on a moderately hydrophobic surface (PEG-600), the effects of salt((NH4)2SO4) concentrations, surface coverage and denaturant (guanidine hydrochloride, GuHCl) concentrations on thermal stability and the changes in the molecular conformation of adsorbed native and denatured lysozyme without aqueous solution were studied with a combination of differential scanning calorimetry (DSC) with FTIR spectroscopy. The results showed that temperature due to endothermic peaks was reduced and the disturbance increased at higher temperature with the increase in salt concentration and surface coverage of adsorbed protein. beta-Sheet and beta-Turn stucture increased while alpha-Helix structure decreased after the adsorption. The peaks corresponding to both C-C stretching frequency in 1400-1425 cm(-1) and amide I band frequency in 1650-1670 cm(-1) of adsorbed denatured lysozyme can be detected in FTIR spectra while that due to amide I band frequency of adsorbed native lysozyme almost can't be observed. Adsorption resulted in structural loss of adsorbed native lysozyme, whose performance was less stable. PMID:19093560

  5. High capacity cryogel-type adsorbents for protein purification.

    PubMed

    Singh, Naveen Kumar; Dsouza, Roy N; Grasselli, Mariano; Fernández-Lahore, Marcelo

    2014-08-15

    Cryogel bodies were modified to obtain epoxy groups by graft-copolymerization using both chemical and gamma irradiation initiation techniques. The free epoxy adsorbents were reacted further to introduce diethylaminoethanol (DEAE) functionalities. The resulting weak anion-exchange cryogel adsorbents showed dynamic binding capacities of ca. 27±3mg/mL, which was significantly higher than previously reported for this type of adsorbent material. Gamma irradiated grafting initiation showed a 4-fold higher capacity for proteins than chemical grafting initiation procedures. The phosphate capacity for these DEAE cryogels was 119mmol/L and also showed similar column efficiency as compared to commercial adsorbents. The large pores in the cryogel structure ensure convective transport of the molecules to active binding sites located on the polymer-grafted surface of cryogels. However, as cryogels have relatively large pores (10-100μm), the BET area available for surface activation is low, and consequently, the capacity of the cryogels is relatively low for biomolecules, especially when compared to commercial beaded adsorbents. Nevertheless, we have shown that gamma ray mediated surface grafting of cryogel matrices greatly enhance their functional and adsorptive properties. PMID:24980092

  6. Contact resistivities of metal-insulator-semiconductor contacts and metal-semiconductor contacts

    NASA Astrophysics Data System (ADS)

    Yu, Hao; Schaekers, Marc; Barla, Kathy; Horiguchi, Naoto; Collaert, Nadine; Thean, Aaron Voon-Yew; De Meyer, Kristin

    2016-04-01

    Applying simulations and experiments, this paper systematically compares contact resistivities (ρc) of metal-insulator-semiconductor (MIS) contacts and metal-semiconductor (MS) contacts with various semiconductor doping concentrations (Nd). Compared with the MS contacts, the MIS contacts with the low Schottky barrier height are more beneficial for ρc on semiconductors with low Nd, but this benefit diminishes gradually when Nd increases. With high Nd, we find that even an "ideal" MIS contact with optimized parameters cannot outperform the MS contact. As a result, the MIS contacts mainly apply to devices that use relatively low doped semiconductors, while we need to focus on the MS contacts to meet the sub-1 × 10-8 Ω cm2 ρc requirement for future Complementary Metal-Oxide-Semiconductor (CMOS) technology.

  7. Contact dermatitis in hairdressers.

    PubMed

    Nethercott, J R; MacPherson, M; Choi, B C; Nixon, P

    1986-02-01

    18 cases of hand dermatitis in hairdressers seen over a 5-year period are reviewed. The diagnoses in these patients are discussed with reference to other studies of hand dermatitis in hairdressers. Contact allergy due to paraphenylenediamine and related hair dyes was the presenting complaint in younger hairdressers, while formaldehyde allergy occurred in those who were older. The prognosis in the former group of workers with respect to continued employment in the trade tended to be poorer than the latter. Follow-up revealed that hand dermatitis often resulted in the worker not continuing to work in the hairdressing trade. PMID:2940055

  8. Adhesive Contact Sweeper

    NASA Technical Reports Server (NTRS)

    Patterson, Jonathan D.

    1993-01-01

    Adhesive contact sweeper removes hair and particles vacuum cleaner leaves behind, without stirring up dust. Also cleans loose rugs. Sweeper holds commercially available spools of inverted adhesive tape. Suitable for use in environments in which air kept free of dust; optics laboratories, computer rooms, and areas inhabited by people allergic to dust. For carpets, best used in tandem with vacuum cleaner; first pass with vacuum cleaner removes coarse particles, and second pass with sweeper extracts fine particles. This practice extends useful life of adhesive spools.

  9. Contact dermatitis to methylisothiazolinone*

    PubMed Central

    Scherrer, Maria Antonieta Rios; Rocha, Vanessa Barreto; Andrade, Ana Regina Coelho

    2015-01-01

    Methylisothiazolinone (MI) is a preservative found in cosmetic and industrial products. Contact dermatitis caused by either methylchloroisothiazolinone/methylisothiazolinone (MCI/MI or Kathon CG) or MI has shown increasing frequency. The latter is preferably detected through epicutaneous testing with aqueous MI 2000 ppm, which is not included in the Brazilian standard tray. We describe a series of 23 patients tested using it and our standard tray. A case with negative reaction to MCI/MI and positive to MI is emphasized. PMID:26734880

  10. Allergic Contact Dermatitis

    PubMed Central

    Nelson, Jenny L.

    2010-01-01

    Epicutaneous patch testing is the gold standard method for the diagnosis of allergic contact dermatitis. Despite this knowledge, many clinical dermatologists do not offer patch testing in their offices or offer testing with only a limited number of allergens. Introduced in 1995, the Thin-Layer Rapid Use Epicutaneous Test originally contained 23 allergens and one control. In 2007, five additional allergens were added. This United States Food and Drug Administration-approved patch testing system made patch testing more convenient, and after its introduction, more dermatologists offered patch testing services. However, the number of allergens in the Thin-Layer Rapid Use Epicutaneous Test remains relatively low. Every two years, the North American Contact Dermatitis Group collects and reports the data from patch testing among its members to a standardized series of allergens. In 2005-2006, the Group used a series of 65 allergens. Of the top 30 allergens reported in 2005-2006, 10 were not included in the Thin-Layer Rapid Use Epicutaneous Test. Knowledge of and testing for additional allergens such as these may increase patch testing yield. PMID:20967194

  11. [Systemic contact dermatitis].

    PubMed

    Nowak, Daria; Gomułka, Krzysztof; Dziemieszonek, Paulina; Panaszek, Bernard

    2016-01-01

    Systemic contact dermatitis (SCD) is a skin inflammation occurring in a patient after systemic administration of a hapten, which previously caused an allergic contact skin reaction in the same person. Most frequently, hypersensitivity reactions typical for SCD occur after absorption of haptens with food or inhalation. Haptens occur mainly in the forms of metals and compounds present in natural resins, preservatives, food thickeners, flavorings and medicines. For many years, several studies have been conducted on understanding the pathogenesis of SCD in which both delayed type hypersensitivity (type IV) and immediate type I are observed. Components of the complement system are also suspected to attend there. Helper T cells (Th) (Th1 and Th2), cytotoxic T lymphocytes (Tc), and NK cells play a crucial role in the pathogenesis of SCD. They secrete a number of pro-inflammatory cytokines. In addition, regulatory T cells (Tregs) have an important role. They control and inhibit activity of the immune system during inflammation. Tregs release suppressor cytokines and interact directly with a target cell through presentation of immunosuppressive particles at the cell surface. Diagnostic methods are generally the patch test, oral provocation test, elimination diet and lymphocyte stimulation test. There are many kinds of inflammatory skin reactions caused by systemic haptens' distribution. They are manifested in a variety of clinical phenotypes of the disease. PMID:26943310

  12. A pH- and Temperature-Responsive Magnetic Composite Adsorbent for Targeted Removal of Nonylphenol.

    PubMed

    Zhen, Yang; Ning, Zhuo; Shaopeng, Zhang; Yayi, Dong; Xuntong, Zhang; Jiachun, Shen; Weiben, Yang; Yuping, Wang; Jianqiang, Chen

    2015-11-11

    A pH- and temperature-responsive magnetic adsorbent [poly(N-isopropylacrylamide) grafted chitosan/Fe3O4 composite particles, CN-MCP], was synthesized for the removal of the endocrine-disrupting chemical nonylphenol. According to the structural characteristics (changeable surface-charge and hydrophilic/hydrophobic properties) of the targeted contaminant, CN-MCP was designed owning special structure (pH- and temperature-responsiveness for the changeable surface-charge and adjustable hydrophilic/hydrophobic properties, respectively). Compared to chitosan magnetic composite particles without grafting modification (CS-MCP) and several other reported adsorbents, CN-MCP exhibited relatively high adsorption capacity for nonylphenol under corresponding optimal conditions (123 mg/g at pH 9 and 20 °C; 116 mg/g at pH 5 and 40 °C). Meanwhile, high selectivity of the novel adsorbent in selective adsorption of nonylphenol from bisolute solution of nonylphenol and phenol was found. Effects of grafting ratio of the grafted polymer branches and coexisting inorganic salts on the adsorption were systematically investigated. Moreover, CN-MCP demonstrated desired reusability during 20 times of adsorption-desorption recycling. The high adsorption capacity, high selectivity, and desired reusability aforementioned revealed the significant application potential of CN-MCP in the removal of NP. On the basis of the adsorption behaviors, isotherms equilibrium, thermodynamics and kinetics studies, and instrumental analyses including X-ray photoelectron spectroscopy, BET specific surface area, zeta potential, and static water contact angle measurements, distinct adsorption mechanisms were found under various conditions: charge attraction between CN-MCP and the contaminant, as well as binding between polymeric branches of CN-MCP and nonyls, contributed to the adsorption at pH 9 and 20 °C; whereas hydrophobic interaction between CN-MCP and nonylphenol played a dominant role at pH 5 and 40

  13. Orientation and order of aqueous organic ions adsorbed to a solid surface

    SciTech Connect

    Sukhishvili, S.A.; Granick, S.

    1999-01-21

    The adsorption and orientation of an aqueous organic ion with anisotropic shape (1,4-dimethylpyridinium, P{sup +}) at the surface of oxidized silicon carrying opposite charge (produced by conditions of high pH) were studied using polarized infrared spectroscopy in attenuated total reflection (FTIR-ATR). Orientation relative to the surface was quantified from the dichroic ratio of in-plane skeletal vibrations of the pyridinium ring (1643 and 1523 cm{sup {minus}1}), and the adsorbed amount was inferred from the intensity of these bands. The sticking energy of the organic ion was slightly larger than that of small inorganic ions of the same charge (Li{sup +}, Na{sup +}, Cs{sup +}). From relative quantities adsorbed in competitive adsorption, the relative sticking energy was quantified ({approximately}7k{sub B}T relative to Na{sup +} at pH = 9.2 and varying in the order Cs{sup +} > Na{sup +} > Li{sup +} by the total amount of 0.6k{sub B}T). At low ionic strength (no inorganic ions present except those in the buffer solution), P{sup +} stood preferably parallel to the surface when the surface coverage was low but more nearly upright both as its surface coverage increased and as the concentration of coadsorbed small ions increased. This shows the influence of steric packing on the orientation of this ion of asymmetric shape. The larger the hydrated diameter of the coadsorbed ion, the more the P{sup +} ion tilted away from the surface (H{sup +} < Li{sup +}, Na{sup +}, Cs{sup +} < Mg{sup 2+}). Furthermore, if the mass adsorbed exceeded a critical level, both the tilt and the amount adsorbed jumped in response to increasing P{sup +} concentration in bulk solution, with hysteresis upon dilution. This jump, together with the measured ellipsometric thickness and contact angle, suggests that the discontinuity involved structural change within a single monolayer. The organic ion thus behaved at the surface as an embryonic amphiphile, although in the bulk, micelle formation has

  14. Unusual Morphologies of Poly(vinyl alcohol) Thin Films Adsorbed on Poly(dimethylsiloxane) Substrates.

    PubMed

    Karki, Akchheta; Nguyen, Lien; Sharma, Bhanushee; Yan, Yan; Chen, Wei

    2016-04-01

    Adsorption of poly(vinyl alcohol) (PVOH), 99% and 88% hydrolyzed poly(vinyl acetate), to poly(dimethylsiloxane) (PDMS) substrates was studied. The substrates were prepared by covalently attaching linear PDMS polymers of 2, 9, 17, 49, and 116 kDa onto silicon wafers. As the PDMS molecular weight/thickness increases, the adsorbed PVOH thin films progressively transition from continuous to discontinuous morphologies, including honeycomb and fractal/droplet. The structures are the result of thin film dewetting that occurs upon exposure to air. The PVOH film thickness does not vary significantly on these PDMS substrates, implicating the PDMS thickness as the cause for the morphology differences. The adsorbed PVOH thin films are less stable and have a stronger tendency to dewet on thicker, more liquid-like PDMS layers. When PVOH(99%) and PVOH(88%) thin films are compared, fractal and droplet morphologies are observed on high molecular weight PDMS substrates, respectively. The formation of the unique fractal features in the PVOH(99%) thin films as well as other crystalline and semicrystalline thin films is most likely driven by crystallization during the dehydration process in a diffusion-limited aggregation fashion. The only significant enhancement in hydrophilicity via PVOH adsorption was obtained on PDMS(2k), which is completely covered with a PVOH thin film. To mimic the lower receding contact angle and less liquid-like character of the PDMS(2k) substrate, light plasma treatment of the higher molecular weight PDMS substrates was carried out. On the treated PDMS substrates, the adsorbed PVOH thin films are in the more continuous honeycomb morphology, giving rise to significantly enhanced wettability. Furthermore, hydrophobic recovery of the hydrophilized PDMS substrates was not observed during a 1 week period. Thus, light plasma oxidation and subsequent PVOH adsorption can be utilized as a means to effectively hydrophilize conventional PDMS substrates. This study

  15. Adsorption of lead ions on composite biopolymer adsorbent

    SciTech Connect

    Seki, Hideshi; Suzuki, Akira

    1996-04-01

    A fundamental study about the application of biopolymers to the recovery of lead from dilute solution was carried out. A membranous composite biopolymer adsorbent containing two kind of biopolymers, alginic acid (AA) and humic acid (HA), was prepared. HA, which has high solubility in water, was almost completely immobilized in the adsorbent by a combination of calcium alginate gel and activated carbon powder. A general model for complexation between divalent metal ions and acidic sites on biopolymers was applied to explain the adsorption mechanism of lead on the adsorbent (HA-M). The results showed that the complexation constants and the complexation capacities of lead-AA and lead-HA systems were scarcely influenced by immobilization.

  16. Method of recovering adsorbed liquid compounds from molecular sieve columns

    DOEpatents

    Burkholder, Harvey R.; Fanslow, Glenn E.

    1983-01-01

    Molecularly adsorbed volatile liquid compounds are recovered from molecular sieve adsorbent columns by directionally applying microwave energy to the bed of the adsorbent to produce a mixed liquid-gas effluent. The gas portion of the effluent generates pressure within the bed to promote the discharge of the effluent from the column bottoms. Preferably the discharged liquid-gas effluent is collected in two to three separate fractions, the second or intermediate fraction having a substantially higher concentration of the desorbed compound than the first or third fractions. The desorption does not need to be assisted by passing a carrier gas through the bed or by applying reduced pressure to the outlet from the bed.

  17. SERS effect of isonicotinic acid adsorbed on a copper electrode

    NASA Astrophysics Data System (ADS)

    Noda, Lucia K.; Sala, O.

    1987-11-01

    The surface enhanced Raman spectra (SERS) of isonicotinic acid adsorbed on a copper electrode were obtained in order to verify their dependence on the type of electrolyte solution, pH and applied potential. The results are discussed considering the most characteristic bands of the species (protonated or nonprotonated) in the ring nitrogen and in the carboxylic group. In specifically adsorbed electrolytes (Cl - and mainly I -) the completely protonated species is more stabilized on the electrode surface than it is in non-specifically adsorbed anions (ClO -4), because of the formation of ion pairs with the coadsorbed halide ions. For more negative potentials, even at low pH values, the spectra are characteristic of the nonprotonated species.

  18. Method of recovering adsorbed liquid compounds from molecular sieve columns

    DOEpatents

    Burkholder, H.R.; Fanslow, G.E.

    1983-12-20

    Molecularly adsorbed volatile liquid compounds are recovered from molecular sieve adsorbent columns by directionally applying microwave energy to the bed of the adsorbent to produce a mixed liquid-gas effluent. The gas portion of the effluent generates pressure within the bed to promote the discharge of the effluent from the column bottoms. Preferably the discharged liquid-gas effluent is collected in two to three separate fractions, the second or intermediate fraction having a substantially higher concentration of the desorbed compound than the first or third fractions. The desorption does not need to be assisted by passing a carrier gas through the bed or by applying reduced pressure to the outlet from the bed. 8 figs.

  19. Lotus Dust Mitigation Coating and Molecular Adsorber Coating

    NASA Technical Reports Server (NTRS)

    O'Connor, Kenneth M.; Abraham, Nithin S.

    2015-01-01

    NASA Goddard Space Flight Center has developed two unique coating formulations that will keep surfaces clean and sanitary and contain contaminants.The Lotus Dust Mitigation Coating, modeled after the self-cleaning, water-repellant lotus leaf, disallows buildup of dust, dirt, water, and more on surfaces. This coating, has been successfully tested on painted, aluminum, glass, silica, and some composite surfaces, could aid in keeping medical assets clean.The Molecular Adsorber Coating is a zeolite-based, sprayable molecular adsorber coating, designed to prevent outgassing in materials in vacuums. The coating works well to adsorb volatiles and contaminates in manufacturing and processing, such as in pharmaceutical production. The addition of a biocide would also aid in controlling bacteria levels.

  20. High-performances carbonaceous adsorbents for hydrogen storage

    NASA Astrophysics Data System (ADS)

    Zhao, Weigang; Fierro, Vanessa; Aylon, E.; Izquierdo, M. T.; Celzard, Alain

    2013-03-01

    Activated carbons (ACs) with controlled microporosity have been prepared and their H2 storage performances have been tested in a gravimetric device. Such adsorbents are natural Chinese anthracites chemically activated with alkaline hydroxides, NaOH or KOH. Outstanding total storage capacities of hydrogen, as high as 6.6wt.% equivalent to excess capacity of 6.2 wt.%, have been obtained at 4MPa for some of these adsorbents. These values of hydrogen adsorption are among the best, if not the highest, ever published so far in the open literature. They are well above those of some commercial materials, e.g. Maxsorb-3, considered as a reference of high-performance adsorbent for hydrogen adsorption. Such exceptional storage capacities may be ascribed to a higher volume of micropores (< 2nm).