Science.gov

Sample records for agp silica monolith

  1. Selective oxidation of cyclohexene through gold functionalized silica monolith microreactors

    NASA Astrophysics Data System (ADS)

    Alotaibi, Mohammed T.; Taylor, Martin J.; Liu, Dan; Beaumont, Simon K.; Kyriakou, Georgios

    2016-04-01

    Two simple, reproducible methods of preparing evenly distributed Au nanoparticle containing mesoporous silica monoliths are investigated. These Au nanoparticle containing monoliths are subsequently investigated as flow reactors for the selective oxidation of cyclohexene. In the first strategy, the silica monolith was directly impregnated with Au nanoparticles during the formation of the monolith. The second approach was to pre-functionalize the monolith with thiol groups tethered within the silica mesostructure. These can act as evenly distributed anchors for the Au nanoparticles to be incorporated by flowing a Au nanoparticle solution through the thiol functionalized monolith. Both methods led to successfully achieving even distribution of Au nanoparticles along the length of the monolith as demonstrated by ICP-OES. However, the impregnation method led to strong agglomeration of the Au nanoparticles during subsequent heating steps while the thiol anchoring procedure maintained the nanoparticles in the range of 6.8 ± 1.4 nm. Both Au nanoparticle containing monoliths as well as samples with no Au incorporated were tested for the selective oxidation of cyclohexene under constant flow at 30 °C. The Au free materials were found to be catalytically inactive with Au being the minimum necessary requirement for the reaction to proceed. The impregnated Au-containing monolith was found to be less active than the thiol functionalized Au-containing material, attributable to the low metal surface area of the Au nanoparticles. The reaction on the thiol functionalized Au-containing monolith was found to depend strongly on the type of oxidant used: tert-butyl hydroperoxide (TBHP) was more active than H2O2, likely due to the thiol induced hydrophobicity in the monolith.

  2. The Advanced Virgo monolithic fused silica suspension

    NASA Astrophysics Data System (ADS)

    Aisa, D.; Aisa, S.; Campeggi, C.; Colombini, M.; Conte, A.; Farnesini, L.; Majorana, E.; Mezzani, F.; Montani, M.; Naticchioni, L.; Perciballi, M.; Piergiovanni, F.; Piluso, A.; Puppo, P.; Rapagnani, P.; Travasso, F.; Vicerè, A.; Vocca, H.

    2016-07-01

    The detection of gravitational waves is one of the most challenging prospects faced by experimental physicists. Suspension thermal noise is an important noise source at operating frequencies between approximately 10 and 30 Hz, and represents a limit to the sensitivity of the ground based interferometric gravitational wave detectors. Its effects can be reduced by minimizing the losses and by optimizing the geometry of the suspension fiber as well as its attachment system. In this proceeding we will describe the mirrors double stage monolithic suspension system to be used in the Advanced Virgo (AdV) detector. We also present the results of the thermal noise study, performed with the help of a finite elements model, taking into account the precise geometry of the fibers attachment systems on the suspension elements. We shall demonstrate the suitability of this suspension for installation in AdV.

  3. Preparing Silica Aerogel Monoliths via a Rapid Supercritical Extraction Method

    PubMed Central

    Gorka, Caroline A.

    2014-01-01

    A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The procedure requires 15-20 min of preparation time, during which a liquid precursor mixture is prepared and poured into wells of a metal mold that is placed between the platens of a hydraulic hot press, followed by several hours of processing within the hot press. The precursor solution consists of a 1.0:12.0:3.6:3.5 x 10-3 molar ratio of tetramethylorthosilicate (TMOS):methanol:water:ammonia. In each well of the mold, a porous silica sol-gel matrix forms. As the temperature of the mold and its contents is increased, the pressure within the mold rises. After the temperature/pressure conditions surpass the supercritical point for the solvent within the pores of the matrix (in this case, a methanol/water mixture), the supercritical fluid is released, and monolithic aerogel remains within the wells of the mold. With the mold used in this procedure, cylindrical monoliths of 2.2 cm diameter and 1.9 cm height are produced. Aerogels formed by this rapid method have comparable properties (low bulk and skeletal density, high surface area, mesoporous morphology) to those prepared by other methods that involve either additional reaction steps or solvent extractions (lengthier processes that generate more chemical waste).The rapid supercritical extraction method can also be applied to the fabrication of aerogels based on other precursor recipes. PMID:24637334

  4. Exploring the pressure resistance limits of monolithic silica capillary columns.

    PubMed

    Hara, Takeshi; Eeltink, Sebastiaan; Desmet, Gert

    2016-05-13

    We report on an experimental approach to measure the pressure stability and mechanical strength of monolithic silica capillary columns with different diameters (50 and 100μm i.d.) and considering two different domain sizes, typical for the second generation monoliths or smaller. The approach consists of exposing the capillaries to ultra-high pressures (gradually stepwise increased from 20 to 80MPa), with intermediate measurements of the column efficiency, permeability and retention factors to check the mechanical stability of the bed. It was observed that all tested columns withstood the imposed pressure stress, i.e., all the tested parameters remained unaffected up till the maximal test pressure of 80MPa. The applied pressure gradient corresponded to 320MPa/m. The two 100μm i.d.-capillary columns were also exposed to pressures between 80 and 90MPa for a prolonged time (8h), and this did not cause any damage either. PMID:27086284

  5. Monolithic Cylindrical Fused Silica Resonators with High Q Factors.

    PubMed

    Pan, Yao; Wang, Dongya; Wang, Yanyan; Liu, Jianping; Wu, Suyong; Qu, Tianliang; Yang, Kaiyong; Luo, Hui

    2016-01-01

    The cylindrical resonator gyroscope (CRG) is a typical Coriolis vibratory gyroscope whose performance is determined by the Q factor and frequency mismatch of the cylindrical resonator. Enhancing the Q factor is crucial for improving the rate sensitivity and noise performance of the CRG. In this paper, for the first time, a monolithic cylindrical fused silica resonator with a Q factor approaching 8 × 10⁵ (ring-down time over 1 min) is reported. The resonator is made of fused silica with low internal friction and high isotropy, with a diameter of 25 mm and a center frequency of 3974.35 Hz. The structure of the resonator is first briefly introduced, and then the experimental non-contact characterization method is presented. In addition, the post-fabrication experimental procedure of Q factor improvement, including chemical and thermal treatment, is demonstrated. The Q factor improvement by both treatments is compared and the primary loss mechanism is analyzed. To the best of our knowledge, the work presented in this paper represents the highest reported Q factor for a cylindrical resonator. The proposed monolithic cylindrical fused silica resonator may enable high performance inertial sensing with standard manufacturing process and simple post-fabrication treatment. PMID:27483263

  6. Monolithic Cylindrical Fused Silica Resonators with High Q Factors

    PubMed Central

    Pan, Yao; Wang, Dongya; Wang, Yanyan; Liu, Jianping; Wu, Suyong; Qu, Tianliang; Yang, Kaiyong; Luo, Hui

    2016-01-01

    The cylindrical resonator gyroscope (CRG) is a typical Coriolis vibratory gyroscope whose performance is determined by the Q factor and frequency mismatch of the cylindrical resonator. Enhancing the Q factor is crucial for improving the rate sensitivity and noise performance of the CRG. In this paper, for the first time, a monolithic cylindrical fused silica resonator with a Q factor approaching 8 × 105 (ring-down time over 1 min) is reported. The resonator is made of fused silica with low internal friction and high isotropy, with a diameter of 25 mm and a center frequency of 3974.35 Hz. The structure of the resonator is first briefly introduced, and then the experimental non-contact characterization method is presented. In addition, the post-fabrication experimental procedure of Q factor improvement, including chemical and thermal treatment, is demonstrated. The Q factor improvement by both treatments is compared and the primary loss mechanism is analyzed. To the best of our knowledge, the work presented in this paper represents the highest reported Q factor for a cylindrical resonator. The proposed monolithic cylindrical fused silica resonator may enable high performance inertial sensing with standard manufacturing process and simple post-fabrication treatment. PMID:27483263

  7. Recent Progress in Monolithic Silica Columns for High-Speed and High-Selectivity Separations

    NASA Astrophysics Data System (ADS)

    Ikegami, Tohru; Tanaka, Nobuo

    2016-06-01

    Monolithic silica columns have greater (through-pore size)/(skeleton size) ratios than particulate columns and fixed support structures in a column for chemical modification, resulting in high-efficiency columns and stationary phases. This review looks at how the size range of monolithic silica columns has been expanded, how high-efficiency monolithic silica columns have been realized, and how various methods of silica surface functionalization, leading to selective stationary phases, have been developed on monolithic silica supports, and provides information on the current status of these columns. Also discussed are the practical aspects of monolithic silica columns, including how their versatility can be improved by the preparation of small-sized structural features (sub-micron) and columns (1 mm ID or smaller) and by optimizing reaction conditions for in situ chemical modification with various restrictions, with an emphasis on recent research results for both topics.

  8. Recent Progress in Monolithic Silica Columns for High-Speed and High-Selectivity Separations.

    PubMed

    Ikegami, Tohru; Tanaka, Nobuo

    2016-06-12

    Monolithic silica columns have greater (through-pore size)/(skeleton size) ratios than particulate columns and fixed support structures in a column for chemical modification, resulting in high-efficiency columns and stationary phases. This review looks at how the size range of monolithic silica columns has been expanded, how high-efficiency monolithic silica columns have been realized, and how various methods of silica surface functionalization, leading to selective stationary phases, have been developed on monolithic silica supports, and provides information on the current status of these columns. Also discussed are the practical aspects of monolithic silica columns, including how their versatility can be improved by the preparation of small-sized structural features (sub-micron) and columns (1 mm ID or smaller) and by optimizing reaction conditions for in situ chemical modification with various restrictions, with an emphasis on recent research results for both topics. PMID:27306311

  9. Preconcentration of milk proteins using octadecylated monolithic silica microchip.

    PubMed

    Alzahrani, Eman; Welham, Kevin

    2013-10-10

    Sample preparation is a bottleneck in systems for chemical analysis and it is a required step in order to remove interference and preconcentrate the target analytes. Much research in recent years has focused on porous monolithic materials since they are highly permeable to liquid flow and show high mass transfer compared with common packed beds. This study has focused on the use of a glass microchip containing an inorganic silica-based monolithic material modified with octadecyl groups for preconcentration of milk proteins from skimmed cows' milk that vary in molecular weight, hydrophobicity, and abundance. Comparison between the fabricated device and a commercial cartridge for the preconcentration of proteins in skimmed cows' milk showed the ability of the device to successfully enrich protein mixtures from the sample. The three replicate experiments showed that the RSD of the mass to charge ratio of milk proteins ranged from 0.01 to 0.46%. In addition, it was found that there were no significant differences between the observed and reported masses of the milk proteins and the relative percentage error of the molecular masses ranged between 0.03 and 0.90%. The fact that the small amounts of sample required and short sample preparation time suggest that this new microfluidic device may be a viable alternative to existing procedures for protein extraction from real samples. PMID:24070482

  10. Fabrication of large-sized silica monolith exceeding 1000 mL with high structural homogeneity.

    PubMed

    Miyamoto, Riichi; Ando, Yukiko; Kurusu, Chie; Bai, Hong-zhi; Nakanishi, Kazuki; Ippommatsu, Masamichi

    2013-06-01

    Reproducible fabrication of the hierarchically porous monolithic silica in a large volume exceeding 1000 mL has been established. By the hydrothermal enlargement of the fully accessible small pores to exceed 50 nm in diameter, the capillary force emerged on solvent evaporation was dramatically reduced, which allowed the preparation of crack-free monoliths with evaporative solvent removal under an ambient pressure. The local temperature inhomogeneity within a reaction vessel in a large volume was precisely controlled to cancel the heat evolved by the hydrolysis reaction of tetramethoxysilane and that consumed to melt ice cubes dispersed in the solution, resulting in large monolithic silica pieces with improved structural homogeneity. Homogeneity of the pore structure was confirmed, both on macro- and mesoscales, using SEM, mercury intrusion, and nitrogen adsorption/desorption measurements. Furthermore, the deviations in chromatographic performance were examined by evaluating multiple smaller monolithic columns prepared from the monolithic silica pieces cut from different parts of a large monolith. All the daughter columns thus prepared exhibited comparable performances to each other to prove the overall homogeneity of the mother monolith. Preliminary results on high-speed separation of peptides and proteins by the octadecylsilylated silica monolith of the above production have also been demonstrated. PMID:23568889

  11. Formation of bimodal porous silica-titania monoliths by sol-gel route

    NASA Astrophysics Data System (ADS)

    Ruzimuradov, O. N.

    2011-10-01

    Silica-titania monoliths with micrometer-scale macroporous and nanometer-scale mesoporous structure and high titania contents are prepared by sol-gel process and phase separation. Titanium alkoxide precursor was not effective in the preparation of high titania content composites because of strong decrease in phase separation tendency. Bimodal porous gels with high titania content were obtained by using inorganic salt precursors such as titanium sulfate and titanium chloride. Various characterization techniques, including SEM, XRD, Hg porosimetry and N2 adsorption have been carried out to investigate the formation process and physical-chemical properties of silica-titania monoliths. The characterization results show that the silica-titania monoliths possess a bimodal porous structure with well-dispersed titania inside silica network. The addition of titania in silica improves the thermal stability of both macroporous and mesoporous structures.

  12. Silica-based polypeptide-monolithic stationary phase for hydrophilic chromatography and chiral separation.

    PubMed

    Zhao, Licong; Yang, Limin; Wang, Qiuquan

    2016-05-13

    Glutathione (GSH)-, somatostatin acetate (ST)- and ovomucoid (OV)-functionalized silica-monolithic stationary phases were designed and synthesized for HILIC and chiral separation using capillary electrochromatography (CEC). GSH, ST and OV were covalently incorporated into the silica skeleton via the epoxy ring-opening reaction between their amino groups and the glycidyl moiety in γ-glycidoxypropyltrimethoxysilane (GPTMS) together with polycondensation and copolymerization of tetramethyloxysilane and GPTMS. Not only could the direction and electroosmotic flow magnitude on the prepared GSH-, ST- and OV-silica hybrid monolithic stationary phases be controlled by the pH of the mobile phase, but also a typical HILIC behavior was observed so that the nucleotides and HPLC peptide standard mixture could be baseline separated using an aqueous mobile phase without any acetonitrile during CEC. Moreover, the prepared monolithic columns had a chiral separation ability to separate dl-amino acids. The OV-silica hybrid monolithic column was most effective in chiral separation and could separate dl-glutamic acid (Glu) (the resolution R=1.07), dl-tyrosine (Tyr) (1.57) and dl-histidine (His) (1.06). Importantly, the chiral separation ability of the GSH-silica hybrid monolithic column could be remarkably enhanced when using gold nanoparticles (AuNPs) to fabricate an AuNP-mediated GSH-AuNP-GSH-silica hybrid monolithic column. The R of dl-Glu, dl-Tyr and dl-His reached 1.19, 1.60 and 2.03. This monolithic column was thus applied to separate drug enantiomers, and quantitative separation of all four R/S drug enantiomers were achieved with R ranging from 4.36 to 5.64. These peptide- and protein-silica monolithic stationary phases with typical HILIC separation behavior and chiral separation ability implied their promise for the analysis of not only the future metabolic studies, but also drug enantiomers recognition.

  13. Feasibility of the preparation of silica monoliths for gas chromatography: fast separation of light hydrocarbons.

    PubMed

    Azzouz, Imadeddine; Essoussi, Anouar; Fleury, Joachim; Haudebourg, Raphael; Thiebaut, Didier; Vial, Jerome

    2015-02-27

    The preparation conditions of silica monoliths for gas chromatography were investigated. Silica-based monolithic capillary columns based on sol-gel process were tested in the course of high-speed gas chromatographic separations of light hydrocarbons mixture (C1-C4). The impact of modifying the amount of porogen and/or catalyst on the monolith properties were studied. At the best precursor/catalyst/porogen ratio evaluated, a column efficiency of about 6500 theoretical plates per meter was reached with a very good resolution (4.3) for very light compounds (C1-C2). The test mixture was baseline separated on a 70cm column. To our knowledge for the first time a silica-based monolithic capillary column was able to separate light hydrocarbons from methane to n-butane at room temperature with a back pressure in the range of gas chromatography facilities (under 4.1bar).

  14. Feasibility of the preparation of silica monoliths for gas chromatography: fast separation of light hydrocarbons.

    PubMed

    Azzouz, Imadeddine; Essoussi, Anouar; Fleury, Joachim; Haudebourg, Raphael; Thiebaut, Didier; Vial, Jerome

    2015-02-27

    The preparation conditions of silica monoliths for gas chromatography were investigated. Silica-based monolithic capillary columns based on sol-gel process were tested in the course of high-speed gas chromatographic separations of light hydrocarbons mixture (C1-C4). The impact of modifying the amount of porogen and/or catalyst on the monolith properties were studied. At the best precursor/catalyst/porogen ratio evaluated, a column efficiency of about 6500 theoretical plates per meter was reached with a very good resolution (4.3) for very light compounds (C1-C2). The test mixture was baseline separated on a 70cm column. To our knowledge for the first time a silica-based monolithic capillary column was able to separate light hydrocarbons from methane to n-butane at room temperature with a back pressure in the range of gas chromatography facilities (under 4.1bar). PMID:25622518

  15. Positron detection in silica monoliths for miniaturised quality control of PET radiotracers.

    PubMed

    Tarn, Mark D; Maneuski, Dzmitry; Alexander, Richard; Brown, Nathaniel J; O'Shea, Val; Pimlott, Sally L; Pamme, Nicole; Archibald, Stephen J

    2016-06-01

    We demonstrate the use of the miniaturised Medipix positron sensor for detection of the clinical PET radiotracer, [(68)Ga]gallium-citrate, on a silica-based monolith, towards microfluidic quality control. The system achieved a far superior signal-to-noise ratio compared to conventional sodium iodide-based radio-HPLC detection and allowed real-time visualisation of positrons in the monolith. PMID:27029282

  16. Ground, sieved, and C18 modified monolithic silica particles for packing material of microcolumn high-performance liquid chromatography.

    PubMed

    Ko, Joung Ho; Baik, Yoon Suk; Park, Seong Tae; Cheong, Won Jo

    2007-03-16

    We here report a new type of stationary phase for microcolumns. C18 modified silica monolith particles were prepared by grinding and sieving the silica monolith followed by C18 modification and end-capping, and were used as packing material. Ground silica monolith particles were not spherical but irregular with some residual monolithic network structure. The separation efficiency of the stationary phase made of sieved monolith particles (5-10 microm) was better than that of the stationary phase made of unsieved particles. The microcolumn packed with the sieved C18 ground monolith particles (5-10 microm) showed quite good separation efficiency (height equivalent to theoretical plate, HETP, as low as 15 microm) and it was even superior to the microcolumn packed with a commercial spherical 5 microm C18 stationary phase. The column pressure drop of C18 monolith particles was about two-third of that of the commercial spherical C18 phase. The preparation method of C18 stationary phase with ground and sieved silica monolith particles presumably suggests advantages of simplicity and convenience in modification and washing procedures compared to bulk silica monolith. It also showed both improved separation efficiency and low back pressure. PMID:17289065

  17. Thick silica gel coatings on methylsilsesquioxane monoliths using anisotropic phase separation.

    PubMed

    Kanamori, Kazuyoshi; Nakanishi, Kazuki; Hanada, Teiichi

    2006-11-01

    Silica gel coatings on methyltrimethoxysilane (MTMS)-derived monoliths have been studied using wetting transition. Wetting transition is observed in a small confined space, where a coating solution phase-separates into a well-coarsened dimension, making all the phase-separating polymerizing silica phase dynamically flow onto the existing surface of a mold. Bulk coating experiments have shown reductions of both macropore volume and diameter due to the coated layer. Comparing HPLC efficiencies of the coated monolith with those of the non-coated MTMS monolith revealed that the retention factors drastically increased in both normal- and reversed-phase modes. This is attributed to the existence of considerable amounts of accessible micropores left inside the coated layer, where analyte molecules travel and adsorb for a considerable period of time.

  18. Monolithic stationary phases with incorporated fumed silica nanoparticles. Part II. Polymethacrylate-based monolithic column with "covalently" incorporated modified octadecyl fumed silica nanoparticles for reversed-phase chromatography.

    PubMed

    Aydoğan, Cemil; El Rassi, Ziad

    2016-05-01

    This study is concerned with the incorporation of surface modified fumed silica nanoparticles (FSNPs) into polymethacrylate based monolithic columns for use in reversed phase chromatography (RPC) of small solutes and proteins. First, FSNPs were modified with 3-(trimethoxysilyl)propylmethacrylate (TMSPM) to yield the "hybrid" methacryloyl fumed silica nanoparticle (MFSNP) monomer. The resulting MFSNP was then mixed with glyceryl monomethacrylate (GMM) and ethylene dimethacrylate (EDMA) in a binary porogenic solvent composed of cyclohexanol and dodecanol, and the in situ copolymerization of MFSNP, GMM and EDMA was performed in a stainless steel column of 4.6 mm i.d. The silanol groups of the hybrid monolith thus obtained were grafted with octadecyl ligands by perfusing the hybrid monolithic column with a solution of 4% w/v of dimethyloctadecylchlorosilane (DODCS) in toluene while the column was maintained at 110°C for 6h (in a heated HPLC oven). One of the originalities of this study was to demonstrate MFSNP as a novel derivatized "hybrid monomer" in making RPC monolithic columns with surface bound octadecyl ligands. In this respect, the RPC behavior of the monolithic column with "covalently" incorporated FNSPs having surface grafted octadecyl ligands was evaluated with alkylbenzenes, aniline derivatives and phenolic compounds. The results showed that the hybrid poly(GMA-EDMA-MFSNP) having surface bound octadecyl ligands exhibited hydrophobic interactions under reversed phase elution conditions. Furthermore, six standard proteins were baseline separated on the column using a 10min linear gradient elution at increasing ACN concentration in the mobile phase at a flow rate of 1.0mL/min using a 10 cm×4.6mm i.d. column. The relative standard deviations (RSDs) for the retention times of the tested solutes were lower than 2.1% and 2.4% under isocratic elution and gradient elution conditions, respectively. PMID:27059396

  19. Monolithic stationary phases with incorporated fumed silica nanoparticles. Part I. Polymethacrylate-based monolithic column with incorporated bare fumed silica nanoparticles for hydrophilic interaction liquid chromatography.

    PubMed

    Aydoğan, Cemil; El Rassi, Ziad

    2016-05-01

    Fumed silica nanoparticles (FSNPs), were incorporated for the first time into a polymethacrylate monolithic column containing glyceryl monomethacrylate (GMM) and ethylene dimethacrylate (EDMA) in order to develop a new monolithic column for hydrophilic interaction high performance liquid chromatography (HILIC). When compared to poly(GMM-EDMA) monolithic column without FSNPs, the same monolithic column with incorporated FSNPs yielded important effects on HILIC separations. The effects of monomers and FSNPs content of the polymerization mixture on the performance of the monolithic column were examined in details, and the optimized stationary phase was investigated over a wide range of mobile phase composition with polar acidic, weakly basic and neutral analytes including hydroxy benzoic acids, nucleotides, nucleosides, dimethylformamide, formamide and thiourea. The retention of these analytes was mainly controlled by hydrophilic interactions with the FSNPs and electrostatic repulsion from the negatively charged silica surface in the case of hydroxy benzoic acids and nucleotides. The electrostatic repulsion was minimized by decreasing the pH of the aqueous component of the mobile phase, which in turn enhanced the retention of acidic solutes. Nucleotides were best separated using step gradient elution at decreasing pH as well as ACN concentration in the mobile phase. Improved peak shape and faster analysis of nucleosides were attained by a fast linear gradient elution with a shallow decrease in the ACN content of the ACN-rich mobile phase. The run-to-run and column-to-column reproducibility were satisfactory. The percent relative standard deviations (%RSDs) for the retention times of tested solutes were lower than 2.5% under isocratic conditions and lower than 3.5 under gradient conditions. PMID:27059399

  20. Monolithic stationary phases with incorporated fumed silica nanoparticles. Part I. Polymethacrylate-based monolithic column with incorporated bare fumed silica nanoparticles for hydrophilic interaction liquid chromatography.

    PubMed

    Aydoğan, Cemil; El Rassi, Ziad

    2016-05-01

    Fumed silica nanoparticles (FSNPs), were incorporated for the first time into a polymethacrylate monolithic column containing glyceryl monomethacrylate (GMM) and ethylene dimethacrylate (EDMA) in order to develop a new monolithic column for hydrophilic interaction high performance liquid chromatography (HILIC). When compared to poly(GMM-EDMA) monolithic column without FSNPs, the same monolithic column with incorporated FSNPs yielded important effects on HILIC separations. The effects of monomers and FSNPs content of the polymerization mixture on the performance of the monolithic column were examined in details, and the optimized stationary phase was investigated over a wide range of mobile phase composition with polar acidic, weakly basic and neutral analytes including hydroxy benzoic acids, nucleotides, nucleosides, dimethylformamide, formamide and thiourea. The retention of these analytes was mainly controlled by hydrophilic interactions with the FSNPs and electrostatic repulsion from the negatively charged silica surface in the case of hydroxy benzoic acids and nucleotides. The electrostatic repulsion was minimized by decreasing the pH of the aqueous component of the mobile phase, which in turn enhanced the retention of acidic solutes. Nucleotides were best separated using step gradient elution at decreasing pH as well as ACN concentration in the mobile phase. Improved peak shape and faster analysis of nucleosides were attained by a fast linear gradient elution with a shallow decrease in the ACN content of the ACN-rich mobile phase. The run-to-run and column-to-column reproducibility were satisfactory. The percent relative standard deviations (%RSDs) for the retention times of tested solutes were lower than 2.5% under isocratic conditions and lower than 3.5 under gradient conditions.

  1. Monolithic stationary phases with incorporated fumed silica nanoparticles. Part II. Polymethacrylate-based monolithic column with "covalently" incorporated modified octadecyl fumed silica nanoparticles for reversed-phase chromatography.

    PubMed

    Aydoğan, Cemil; El Rassi, Ziad

    2016-05-01

    This study is concerned with the incorporation of surface modified fumed silica nanoparticles (FSNPs) into polymethacrylate based monolithic columns for use in reversed phase chromatography (RPC) of small solutes and proteins. First, FSNPs were modified with 3-(trimethoxysilyl)propylmethacrylate (TMSPM) to yield the "hybrid" methacryloyl fumed silica nanoparticle (MFSNP) monomer. The resulting MFSNP was then mixed with glyceryl monomethacrylate (GMM) and ethylene dimethacrylate (EDMA) in a binary porogenic solvent composed of cyclohexanol and dodecanol, and the in situ copolymerization of MFSNP, GMM and EDMA was performed in a stainless steel column of 4.6 mm i.d. The silanol groups of the hybrid monolith thus obtained were grafted with octadecyl ligands by perfusing the hybrid monolithic column with a solution of 4% w/v of dimethyloctadecylchlorosilane (DODCS) in toluene while the column was maintained at 110°C for 6h (in a heated HPLC oven). One of the originalities of this study was to demonstrate MFSNP as a novel derivatized "hybrid monomer" in making RPC monolithic columns with surface bound octadecyl ligands. In this respect, the RPC behavior of the monolithic column with "covalently" incorporated FNSPs having surface grafted octadecyl ligands was evaluated with alkylbenzenes, aniline derivatives and phenolic compounds. The results showed that the hybrid poly(GMA-EDMA-MFSNP) having surface bound octadecyl ligands exhibited hydrophobic interactions under reversed phase elution conditions. Furthermore, six standard proteins were baseline separated on the column using a 10min linear gradient elution at increasing ACN concentration in the mobile phase at a flow rate of 1.0mL/min using a 10 cm×4.6mm i.d. column. The relative standard deviations (RSDs) for the retention times of the tested solutes were lower than 2.1% and 2.4% under isocratic elution and gradient elution conditions, respectively.

  2. Hydrothermal preparation of hybrid carbon/silica monolithic capillary column for liquid chromatography.

    PubMed

    Yang, Peiling; Wang, Wentao; Xiao, Xing; Jia, Li

    2014-08-01

    A simple, easy and economical approach for the preparation of a hybrid carbon/silica monolithic capillary column was described for the first time by using silica monolith as framework in combination with hydrothermal carbonization at 180°C. During the preparation process, formamide was introduced to the reaction solutions to reduce the dissolution rate of monolithic silica skeleton and its optimal concentration was 1.5 M. Fourier transform infrared spectrometry, scanning electron microscopy, energy dispersive X-ray spectrometry, and inverse size exclusion chromatography were carried out to characterize the as-prepared column. The results demonstrated that carbon spheres ranging from 150 to 1000 nm were successfully attached to the surface of silica skeleton. The prepared hybrid carbon/silica column had a permeability of 4.4 × 10(-14) m(2). Chromatographic performance of the column was evaluated by separation of various compounds including alkylbenzenes, nucleosides and bases, and aromatic acids. The column exhibited an efficiency of 75,000 plates/m for butylbenzene at the optimal linear velocity of 0.23 mm/s. The successful separation of these compounds and the study on mechanism indicated that the column can be applied in mixed-mode chromatography. PMID:24830747

  3. The use of carrier RNA to enhance DNA extraction from microfluidic-based silica monoliths.

    PubMed

    Shaw, Kirsty J; Thain, Lauren; Docker, Peter T; Dyer, Charlotte E; Greenman, John; Greenway, Gillian M; Haswell, Stephen J

    2009-10-12

    DNA extraction was carried out on silica-based monoliths within a microfluidic device. Solid-phase DNA extraction methodology was applied in which the DNA binds to silica in the presence of a chaotropic salt, such as guanidine hydrochloride, and is eluted in a low ionic strength solution, such as water. The addition of poly-A carrier RNA to the chaotropic salt solution resulted in a marked increase in the effective amount of DNA that could be recovered (25ng) compared to the absence of RNA (5ng) using the silica-based monolith. These findings confirm that techniques utilising nucleic acid carrier molecules can enhance DNA extraction methodologies in microfluidic applications.

  4. Facile preparation of organic-silica hybrid monolith for capillary hydrophilic liquid chromatography based on "thiol-ene" click chemistry.

    PubMed

    Chen, Ming-Luan; Zhang, Jun; Zhang, Zheng; Yuan, Bi-Feng; Yu, Qiong-Wei; Feng, Yu-Qi

    2013-04-01

    In this work, a one-step approach to facile preparation of organic-inorganic hybrid monoliths was successfully developed. After vinyl-end organic monomers and azobisisobutyronitrile (AIBN) were mixed with hydrolyzed tetramethoxysilane (TMOS) and 3-mercaptopropyltrimethoxysilane (MPTMS), the homogeneous mixture was introduced into a fused-silica capillary for simultaneous polycondensation and "thiol-ene" click reaction to form the organic-silica hybrid monoliths. By employing this strategy, two types of organic-silica hybrid monoliths with positively charged quaternary ammonium and amide groups were prepared, respectively. The functional groups were successfully introduced onto the monoliths during the sol-gel process with "thiol-ene" click reaction, which was demonstrated by ζ-potential assessment, energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared (FT-IR) spectroscopy. The porous structure of the prepared monolithic columns was examined by scanning electron microscopy (SEM), nitrogen adsorption-desorption measurement, and mercury intrusion porosimetry. These results indicate the prepared organic-silica hybrid monoliths possess homogeneous column bed, large specific surface area, good mechanical stability, and excellent permeability. The prepared monolithic columns were then applied for anion-exchange/hydrophilic interaction liquid chromatography. Different types of analytes, including benzoic acids, inorganic ions, nucleosides, and nucleotides, were well separated with high column efficiency around 80,000-130,000 plates/m. Taken together, we present a facile and universal strategy to prepare organic-silica hybrid monoliths with a variety of organic monomers using one-step approach.

  5. Facile preparation of organic-silica hybrid monolith for capillary hydrophilic liquid chromatography based on "thiol-ene" click chemistry.

    PubMed

    Chen, Ming-Luan; Zhang, Jun; Zhang, Zheng; Yuan, Bi-Feng; Yu, Qiong-Wei; Feng, Yu-Qi

    2013-04-01

    In this work, a one-step approach to facile preparation of organic-inorganic hybrid monoliths was successfully developed. After vinyl-end organic monomers and azobisisobutyronitrile (AIBN) were mixed with hydrolyzed tetramethoxysilane (TMOS) and 3-mercaptopropyltrimethoxysilane (MPTMS), the homogeneous mixture was introduced into a fused-silica capillary for simultaneous polycondensation and "thiol-ene" click reaction to form the organic-silica hybrid monoliths. By employing this strategy, two types of organic-silica hybrid monoliths with positively charged quaternary ammonium and amide groups were prepared, respectively. The functional groups were successfully introduced onto the monoliths during the sol-gel process with "thiol-ene" click reaction, which was demonstrated by ζ-potential assessment, energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared (FT-IR) spectroscopy. The porous structure of the prepared monolithic columns was examined by scanning electron microscopy (SEM), nitrogen adsorption-desorption measurement, and mercury intrusion porosimetry. These results indicate the prepared organic-silica hybrid monoliths possess homogeneous column bed, large specific surface area, good mechanical stability, and excellent permeability. The prepared monolithic columns were then applied for anion-exchange/hydrophilic interaction liquid chromatography. Different types of analytes, including benzoic acids, inorganic ions, nucleosides, and nucleotides, were well separated with high column efficiency around 80,000-130,000 plates/m. Taken together, we present a facile and universal strategy to prepare organic-silica hybrid monoliths with a variety of organic monomers using one-step approach. PMID:23434082

  6. Dipyridyl-immobilized ionic liquid type hybrid silica monolith for hydrophilic interaction electrochromatography.

    PubMed

    Wang, Xiao; Zheng, Na; Huang, Yifang; Wang, Jiabin; Lin, Xucong; Xie, Zenghong

    2013-11-01

    A pyridinium-based immobilized ionic liquid type multifunctional hybrid silica monolith was prepared by the in situ polymerization of 3-chloropropyl-silica matrix and 4,4'-dipyridyl for hydrophilic interaction CEC. The obtained hybrid monolith possessed of high stable skeletal microstructures with obviously hydrophilic retention mechanism under ACN content >50% in the mobile phase. Strong and stable anodic EOF could be observed under a broad pH range from pH 3.0 to 9.0. Due to the immobilized dipyridyl groups bonded to the silica matrix surface, the resulting hydrophilic hybrid monolith possessed multiple separation interactions including hydrogen bond, π-π, and anion exchange. Excellent separations of various polar analytes including electroneutral phenols, charged acid nucleotides, and basic analytes were successfully achieved. The highest column efficiencies up to 120,000, 164,000, and 106,000 plates/m were obtained for nucleotides, nucleic acid bases, and nucleosides and nicotines, respectively. These results demonstrated that the dipyridyl-immobilized ionic liquid functionalized hybrid monolith possessed highly mechanical stability and good chromatographic performance for hydrophilic interaction electrochromatography.

  7. Combination of porous silica monolith and gold thin films for electrode material of supercapacitor

    NASA Astrophysics Data System (ADS)

    Pastre, A.; Cristini-Robbe, O.; Boé, A.; Raulin, K.; Branzea, D.; El Hamzaoui, H.; Kinowski, C.; Rolland, N.; Bernard, R.

    2015-12-01

    An all-solid electrical double layer supercapacitor was prepared, starting from a porous silica matrix coated with a gold thin-film. The metallization of the silica xerogel was performed by an original wet chemical process, based on the controlled growth of gold nanoparticles on two opposite faces of the silica monolith as a seed layer, followed by an electroless deposition of a continuous gold thin film. The thickness of the metallic thin film was assessed to be 700 nm. The silica plays two major roles: (1) it is used as a porous matrix for the gold electrode, creating a large specific surface area, and (2) it acts as a separator (non-metallized part of the silica). The silica monolith was soaked in a polyvinyl alcohol and phosphoric acid mixture which is used as polymer electrolyte. Capacitance effect was demonstrated by cyclic voltammetry experiments. The specific capacitance was found to be equal to 0.95 mF cm- 2 (9.5 F g-1). No major degradation occurs within more than 3000 cycles.

  8. Co(2+)@Mesoporous Silica Monoliths: Tailor-Made Nanoreactors for Confined Soft Chemistry.

    PubMed

    Delahaye, Emilie; Moulin, Robinson; Aouadi, Merwen; Trannoy, Virgile; Beaunier, Patricia; Fornasieri, Giulia; Bleuzen, Anne

    2015-11-16

    Mesoporous silica monoliths with various ordered nanostructures containing transition metal M(2+) cations in variable amounts were elaborated and studied. A phase diagram depicting the different phases as a function of the M(2+) salt/tetramethyl orthosilicate (TMOS) and surfactant P123/TMOS ratios was established. Thermal treatment resulted in mesoporous monoliths containing isolated, accessible M(2+) species or condensed metal oxides, hydroxides, and salts, depending on the strength of the interactions between the metal species and the ethylene oxide units of P123. The ordered mesoporosity of the monoliths containing accessible M(2+) ions was used as a nanoreactor for the elaboration of various transition metal compounds (Prussian blue analogues, Hofmann compounds, metal-organic frameworks), and this opens the way to the elaboration of a large range of nanoparticles of multifunctional materials.

  9. One-pot synthesis of a new high vinyl content hybrid silica monolith dedicated to nanoliquid chromatography.

    PubMed

    Racha, El-Debs; Gay, Pauline; Dugas, Vincent; Demesmay, Claire

    2016-03-01

    A new vinyltrimethoxysilane-based hybrid silica monolith was developed and used as a reversed-phase capillary column. The synthesis of this rich vinyl hybrid macroporous monolith, by cocondensation of vinyltrimethoxysilane with tetramethoxysilane, was investigated using an unconventional (formamide, nitric acid) porogen/catalyst system. A macroporous hybrid silica monolith with 80% in mass of vinyltrimethoxysilane in the feeding silane solution was obtained and compared to a more conventional low vinyl content hybrid monolith with only of 20% vinyltrimethoxysilane. Monoliths were characterized by scanning electron microscopy, (29) Si nuclear magnetic resonance spectroscopy and N2 adsorption-desorption. About 80% of the vinyl precursor was incorporated in the final materials, leading to 15.9 and 61.5% of Si atoms bonded to vinyl groups for 20% vinyltrimethoxysilane and 80% vinyltrimethoxysilane, respectively. The 80% vinyltrimethoxysilane monolith presents a lower surface area than 20% vinyltrimethoxysilane (159 versus 551 m(2) /g), which is nevertheless compensated by a higher vinyl surface density. Chromatographic properties were evaluated in reversed-phase mode. Plots of ln(k) versus percentage of organic modifier were used to assess the reversed-phase mechanism. Its high content of organic groups leads to high retention properties. Column efficiencies of 170 000 plates/m were measured for this 80% vinyltrimethoxysilane hybrid silica monolith. Long capillary monolithic columns (90 cm) were successfully synthesized (N = 120 000).

  10. Separation of hydrophobic metabolites using monolithic silica column in high-performance liquid chromatography and supercritical fluid chromatography.

    PubMed

    Bamba, Takeshi; Fukusaki, Eiichiro

    2009-08-01

    Monolithic silica columns have very low back-pressures and offer several advantages over conventional columns packed with spherical particles, such as high separation efficiency and rapid analysis. In this review, we report the applicability of monolithic silica columns for the analysis of complex hydrophobic metabolites. We have used monolithic columns in HPLC and developed a separation technique for the high-speed and high-resolution analysis of the geometric analogs of natural polyprenols. We also used monolithic columns in supercritical fluid chromatography for the successful separation of the structural isomers of carotenoids after deciding the analytical conditions that were suitable for this separation and have developed a method for profiling biological samples containing complex matrices. We have proved that excellent resolution can be obtained by connecting a number of monolithic columns in series.

  11. On-chip generation and demultiplexing of quantum correlated photons using a silicon-silica monolithic photonic integration platform.

    PubMed

    Matsuda, Nobuyuki; Karkus, Peter; Nishi, Hidetaka; Tsuchizawa, Tai; Munro, William J; Takesue, Hiroki; Yamada, Koji

    2014-09-22

    We demonstrate the generation and demultiplexing of quantum correlated photons on a monolithic photonic chip composed of silicon and silica-based waveguides. Photon pairs generated in a nonlinear silicon waveguide are successfully separated into two optical channels of an arrayed-waveguide grating fabricated on a silica-based waveguide platform.

  12. High efficiency, high temperature separations on silica based monolithic columns.

    PubMed

    Rogeberg, Magnus; Wilson, Steven Ray; Malerod, Helle; Lundanes, Elsa; Tanaka, Nobuo; Greibrokk, Tyge

    2011-10-14

    The effect of temperature on separation using reversed-phase monolithic columns has been investigated using a nano-LC pumping system for gradient separation of tryptic peptides with MS detection. A goal of this study was to find optimal conditions for high-speed separations. The chromatographic performance of the columns was evaluated by peak capacity and peak capacity per time unit. Column lengths ranging from 20 to 100 cm and intermediate gradient times from 10 to 30 min were investigated to assess the potential of these columns in a final step separation, e.g. after fractionation or specific sample preparation. Flow rates from 250 to 2000 nL/min and temperatures from 20 to 120°C were investigated. Temperature had a significant effect on fast separations, and a flow rate of 2000 nL/min and a temperature of 80°C gave the highest peak capacity per time unit. These settings produced 70% more protein identifications in a biological sample compared to a conventional packed column. Alternatively, an equal amount of protein identifications was obtained with a 40% reduction in run time compared to the conventional packed column.

  13. One-Pot Approach to Prepare Organo-silica Hybrid Capillary Monolithic Column with Intact Mesoporous Silica Nanoparticle as Building Block

    PubMed Central

    Liu, Shengju; Peng, Jiaxi; Liu, Zheyi; Liu, Zhongshan; Zhang, Hongyan; Wu, Ren’an

    2016-01-01

    A facile “one-pot” approach to prepare organo-silica hybrid capillary monolithic column with intact mesoporous silica nanoparticle (IMSN) as crosslinker and building block was described. An IMSN crosslinked octadecyl-silica hybrid capillary monolithic column (IMSN-C18 monolithic column) was successfully prepared, and the effects of fabrication conditions (e.g. concentration of intact mesoporous silica nanoparticle, polycondensation temperature, content of vinyltrimethoxysilane and stearyl methacrylate) on the structures of the IMSN-C18 monolithic column were studied in detail. The IMSN-C18 hybrid monolithic column possessed uniform morphology, good mechanical and pH stability (pH 1.1–11), which was applied to the separations of alkyl benzenes, polycyclic aromatic hydrocarbons (PAHs), as well as proteins. The minimum plate height of 10.5 μm (corresponding to 95000 N m−1) for butylbenzene and high reproducibility were achieved. The analysis of tryptic digest of bovine serum albumin (BSA) was carried out on the IMSN-C18 monolithic column by cLC coupled mass spectrometry (cLC-MS/MS), with the protein sequence coverage of 87.5% for BSA, demonstrating its potential application in proteomics. PMID:27698475

  14. Robust monolithic silica-based on-chip electro-osmotic micro-pump.

    PubMed

    Nie, Fu-Qiang; Macka, Mirek; Barron, Leon; Connolly, Damian; Kent, Nigel; Paull, Brett

    2007-05-01

    A robust, compact, on-chip, electro-osmotic micro-pump (EOP) for micro-flow analysis, based on parallel, encased, 10 x 0.1 mm I.D. monolithic silica capillary columns has been developed. A 15 x 40 x 2 mm poly(methyl methacrylate) (PMMA) chip, containing a total of nine parallel EOP systems was fabricated, allowing the use of single, double or triple monolithic columns to produce increased flow as required. The monolithic silica was compatible with both aqueous and organic solvents without swelling or shrinking problems, with the triple column EOP capable of generating flow of up to 0.6 microL min(-1) under zero pressure load and over 0.1 microL min(-1) with an applied pressure of ca. 2.4 bar using an applied voltage of just 2 kV. Current generated at the 2 kV applied voltage for a 2 mM acetate buffer solution (pH 4.5) was under 4 microA, allowing stable, bubble-free flow. The developed triple column EOP was incorporated within a micro-fluidic chip (5.0 x 2.0 x 0.4 cm) integrated with a second single 10 x 0.1 mm column EOP, for combined sample injection and simple on-chip micro-flow analysis.

  15. Separation of polyprenol and dolichol by monolithic silica capillary column chromatography.

    PubMed

    Bamba, Takeshi; Fukusaki, Eiiciro; Minakuchi, Hiroshi; Nakazawa, Yoshihisa; Kobayashi, Akio

    2005-10-01

    We attempted an analysis of naturally occurring polyprenol and dolichol using a monolithic silica capillary column in HPLC. First, the separation of the polyprenol mixture alone was performed using a 250 x 0.2 mm inner diameter (ID) octadecylsilyl (ODS)-monolithic silica capillary column. The resolution of the separation between octadecaprenol (prenol 18) and nonadecaprenol (prenol 19) exceeded by >or=2-fold the level recorded when using a conventional ODS-silica particle-packed column (250 x 4.6 mm ID) under the same elution conditions. Next, the mixture of the prenol type (polyprenol) and dolichol type (dihydropolyprenol) was subjected to this capillary HPLC system, and the separation of each homolog was successfully achieved. During the analysis of polyprenol fraction derived from Eucommia ulmoides leaves, dolichols were found as a single peak, including all-trans-polyprenol and cis-polyprenol previously identified. This sensitive high-resolution system is very useful for the analysis of compounds that are structurally close to polyprenols and dolichols and that have a low content.

  16. Effect of polyethylene glycol on pore structure and separation efficiency of silica-based monolithic capillary columns.

    PubMed

    Hara, Takeshi; Desmet, Gert; Baron, Gino V; Minakuchi, Hiroyoshi; Eeltink, Sebastiaan

    2016-04-15

    Monolithic silica materials (first unclad monolith rods, then monolithic capillary columns) were prepared using various amounts of polyethylene glycols (PEGs) with different molecular weight (MW). The monolith rods were used to examine the mesoporosity by argon physisorption technique, and the macroporosity by mercury intrusion porosimetry. Subsequently, silica-based monolithic capillary columns with an inner diameter of 100 μm were produced using the same preparation conditions as used for the rods. The results obtained with the monolith rods showed the following important findings: (1) it is feasible to fabricate monolithic silica rods possessing macropore size of 0.5-1.4 μm by tuning the amount of PEGs (independently of the MW), whereas the macropore volume and the mesoporosity remain similar. (2) the smallest macropore size (0.5 μm) rod prepared with PEG having a MW=20,000g/mol provided a narrower macropore size distribution than with PEG with MW=10,000g/mol. The monolithic capillary columns produced with the different PEG type showed similar retention factors for hexylbenzene (k=2.3-2.4) and similar t0-based column permeability (Kv0=2.3-2.4×10(-14)m(2)) in 20:80% (v/v) water:methanol, as expected from the results obtained with the monolith rods. The column prepared with PEG of MW=20,000g/mol gave a plate height of H=4.0 μm for hexylbenzene at an optimal linear velocity of u0=2.6mm/s in 20:80% (v/v) water containing 0.1% formic acid:acetonitrile. To the best of our knowledge, this is the lowest plate height ever recorded for a monolithic column. Comparing the kinetic performance at 30MPa shows that the best monolithic silica column obtained in the present study performs better than the second-generation monolithic silica columns developed up till now in the practically most relevant range of plate numbers (N≤40,000). In this range, the performance is now similar to that of 2.7 μm core-shell particle columns. PMID:26976349

  17. Silica-based monolithic capillary columns modified by liposomes for characterization of analyte-liposome interactions by capillary liquid chromatography.

    PubMed

    Moravcová, Dana; Planeta, Josef; Wiedmer, Susanne K

    2013-11-22

    This study introduces a silica-based monolith in a capillary format (0.1 mm × 100 mm) as a support for immobilization of liposomes and its characterization in immobilized liposome chromatography. Silica-based monolithic capillary columns prepared by acidic hydrolysis of tetramethoxysilane in the presence of polyethylene glycol and urea were modified by (3-aminopropyl)trimethoxysilane, whereby amino groups were introduced to the monolithic surface. These groups undergo reaction with glutaraldehyde to form an iminoaldehyde, allowing covalent binding of pre-formed liposomes containing primary amino groups. Two types of phospholipid vesicles were used for column modification; these were 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphatidyl choline with and without 1,2-diacyl-sn-glycero-3-phospho-L-serine. The prepared columns were evaluated under isocratic separation conditions employing 20mM phosphate buffer at pH 7.4 as a mobile phase and a set of unrelated drugs as model analytes. The liposome layer on the synthesized columns significantly changed the column selectivity compared to the aminopropylsilylated monolithic stationary phase. Monolithic columns modified by liposomes were stable under the separation conditions, which proved the applicability of the suggested preparation procedure for the synthesis of capillary columns dedicated to study analyte-liposome interactions. The column efficiency originating from the silica monolith was preserved and reached, e.g., more than 120,000 theoretical plates/m for caffeine as a solute. PMID:23978749

  18. Rapid and mild purification method for nanoparticles from a dispersed solution using a monolithic silica disk.

    PubMed

    Itoh, Naoki; Santa, Tomofumi; Kato, Masaru

    2015-07-24

    A rapid and mild purification method for nanoparticles using the commercially available monolithic silica disk, MonoSpin(®), was developed. The nanoparticles were purified from a dispersed solution by filtration with the aid of centrifugation at 2290×g for 2min. The purification conditions were rapid, mild, and simple compared with those of the conventional purification methods such as ultracentrifugation, dialysis, size exclusion chromatography, and ultrafiltration. The method was shown to be applicable for the purification of various nanoparticles, regardless of their size (from 21 to 100nm), composition material (silica, polyethylene glycol, and pegylated liposome), and encapsulated molecule (rhodamine 110 and doxorubicin). It was shown that this method is applicable to the purification of a wide range of nanoparticles in many different fields.

  19. Fast HPLC for quality control of Harpagophytum procumbens by using a monolithic silica column: method transfer from conventional particle-based silica column.

    PubMed

    Schmidt, Alexander H

    2005-05-01

    The applicability of a monolithic C18-bonded silica column for the rapid HPLC separation of ingredients in medicinal plants and their phytopharmaceutical preparations has been evaluated in the author's laboratory. In this presentation, an existing method for the determination of the iridoid glycoside harpagoside in Harpagophytum procumbens (Devil's Claw) was successfully transferred from a conventional particle-based C18 silica column to a monolithic silica column. The very high porosity of the stationary phase allows chromatography with a much lower backpressure than on conventional columns. Therefore, the flow rate could be easily increased from 0.8 mL/min (particle-based column) to 5 mL/min (monolithic column) and the run-time reduced from 30 to 5 min (that is a reduction about 85% !), without losing any chromatographic resolution of the compound of interest. The amount of harpagoside was measured with the original method on a conventional particle-based silica column and on the adapted method on a monolithic silica column. The statistical mean t-test showed no significant differences of the variances and the means indicating that the fast HPLC method is an acceptable alternative. The shorter analysis time makes the method very valuable for commercial quality control of Harpagophytum extracts and its pharmaceutical preparations. PMID:15909544

  20. Preparation and complex characterization of silica holmium sol-gel monoliths.

    PubMed

    Cacaina, D; Areva, S; Laaksonen, H; Simon, S; Ylänen, H

    2011-01-01

    Amorphous, sol-gel derived SiO(2) are known to biocompatible and bioresorbable materials. Biodegradable and inert materials containing radioactive isotopes have potential application as delivery vehicles of the beta radiation to the cancer tumors inside the body. Incorporation of holmium in the sol-gel derived SiO(2) could lead to the formation of a biodegradable material which could be used as carrier biomaterial for the radiation of radioactive holmium to the various cancer sites. The homogeneity of the prepared sol-gel silica holmium monoliths was investigated by Back Scattered Electron Imaging of Scanning Electron Microscope equipped with Energy Dispersive X-ray Analysis, X-ray Induced Photoelectron Spectroscopy and Nuclear Magnetic Resonance Spectroscopy. The biodegradation of the monoliths was investigated in Simulated Body Fluid and TRIS (Trizma pre-set Crystals) solution. The results show that by suitable tailoring of the sol-gel processing parameters holmium can be homogeneously incorporated in the silica matrix with a controlled biodegradation rate.

  1. Diffusion of dissolved ions from wet silica sol-gel monoliths: implications for biological encapsulation.

    PubMed

    Dickson, David J; Lassetter, Bethany; Glassy, Benjamin; Page, Catherine J; Yokochi, Alexandre F T; Ely, Roger L

    2013-02-01

    Divalent nickel (Ni(2+)), Cu(II)EDTA, methyl orange, and dichromate were used to investigate diffusion from hydrated silica sol-gel monoliths. The objective was to examine diffusion of compounds on a size regime relevant to supporting biological components encapsulated within silica gel prepared in a biologically compatible process space with no post-gelation treatments. With an initial sample set, gels prepared from tetraethoxysilane were explored in a factorial design with Ni(2+) as the tracer, varying water content during hydrolysis, acid catalyst present during hydrolysis, and the final concentration of silica. A second sample set explored diffusion of all four tracers in gels prepared with aqueous silica precursors and a variety of organically modified siloxanes. Excluding six outliers which displayed significant syneresis, the mean diffusion constant (D(gel)) across the entire process space of sample set 1 was 2.42×10(-10) m(2) s(-1); approximately 24% of the diffusion coefficient of Ni(2+) in unconfined aqueous solution. In sample set 2, the tracer size and not gel hydrophobicity was the primary determinant of changes in diffusion rates. A strong linear inverse correlation was found between tracer size and the magnitude of D(gel). Based on correlation with the tracers used in this investigation, the characteristic 1-h diffusion distance for carbonate species relevant to supporting active phototrophic organisms was approximately 1.5mm. These results support the notion that silica sol-gel formulations may be optimized for a given biological entity of interest with manageable impact to the diffusion of small ions and molecules.

  2. Single-step approach for fabrication of vancomycin-bonded silica monolith as chiral stationary phase.

    PubMed

    Hsieh, Ming-Lung; Chau, Lai-Kwan; Hon, Yung-Son

    2014-09-01

    A vancomycin-bonded silica monolithic column for capillary electrochromatography (CEC) was prepared by a single-step in situ sol-gel approach. This sol-gel process incorporates a synthetic sol-gel precursor which contains a macrocyclic antibiotic, vancomycin, to form a porous silica network inside a fused-silica capillary. To avoid degradation of vancomycin during the column fabrication, a mild step was adopted into the sol-gel process. The performance of the vancomycin chiral stationary phase was investigated by CEC in both the reversed-phase mode and the normal-phase mode. The vancomycin chiral stationary phase was optimized with respect to vancomycin loading in the reversed-phase mode for chiral separation of thalidomide enantiomers. The best efficiency and resolution values of 94600plates/m and 5.79, respectively, were achieved. The optimized column was further applied to chiral separation of alprenolol enantiomers. A plate height of less than 7μm for the first eluted enantiomer of alprenolol was obtained in an aqueous mobile phase at a flow rate of 0.74mm/s. Using enantiomers of seven β-blockers and some other basic enantiomers as test analytes, separation efficiencies of up to 148100plates/m in the reversed-phase mode and up to 138100plates/m in the normal-phase mode were achieved.

  3. One-pot preparation of glutathione-silica hybrid monolith for mixed-mode capillary liquid chromatography based on "thiol-ene" click chemistry.

    PubMed

    Lin, Zian; Tan, Xiaoqing; Yu, Ruifang; Lin, Jiashi; Yin, Xiaofei; Zhang, Lan; Yang, Huanghao

    2014-08-15

    A novel glutathione (GSH)-silica hybrid monolithic column synthesized via a combination of thiol-ene click reaction and one-pot process was described, where thiol-end GSH organic monomer and 2,2-azobisisobutyronitrile (AIBN) were mixed with hydrolyzed tetramethyloxysilane (TMOS) and γ-methacryloxypropyltrimethoxysilane (γ-MAPS) and then introduced into a fused-silica capillary for simultaneous polycondensation and "thiol-ene" click reaction to form the GSH-silica hybrid monolith. The effects of the molar ratio of TMOS/γ-MAPS, the amount of GSH, and the volume of porogen on the morphology, permeability and pore properties of the prepared GSH-silica hybrid monoliths were studied in detail. A uniform monolithic network with high porosity was obtained. A series of test compounds including alkylbenzenes, amides, and anilines were used to evaluate the retention behaviors of the GSH-silica hybrid monolithic column. The results demonstrated that the prepared GSH-silica hybrid monolith exhibited multiple interactions including hydrophobicity, hydrophilicity, as well as cation exchange interaction. The run-to-run, column-to-column and batch-to-batch reproducibilities of the GSH-silica hybrid monolith for phenols' retention were satisfactory with the relative standard deviations (RSDs) less than 1.3% (n=5), 2.6% (n=3) and 3.2% (n=3), respectively, indicating the effectiveness and practicability of the proposed method. In addition, the GSH-silica hybrid monolith was applied to the separation of nucleotides, peptides and protein tryptic digests, respectively. The successful applications suggested the potential of the GSH-silica hybrid monolith in complex sample analysis.

  4. Damping and tuning of the fibre violin modes in monolithic silica suspensions

    NASA Astrophysics Data System (ADS)

    Goßler, S.; Cagnoli, G.; Crooks, D. R. M.; Lück, H.; Rowan, S.; Smith, J. R.; Strain, K. A.; Hough, J.; Danzmann, K.

    2004-03-01

    High Q mirror suspensions are a key element of the advanced interferometric gravitational-wave detectors. In December 2002 the last of the final interferometer optics of GEO 600 were monolithically suspended, using fused silica fibres. The violin modes of the suspension fibres can have Q greater than 108 and can therefore interfere with the interferometer length control servo. Hence, the violin modes need to be damped, without degrading the pendulum Q itself. Furthermore, the frequency spread of the fibres used has to be small to allow for high Q notch filtering in the length control servo. The requirements for the violin modes of the two GEO 600 inboard suspensions are Q < 3 × 106 for the fundamental and Q < 2 × 106 for the first harmonic mode, respectively. The frequency spread should not exceed 10% within one mode. To accomplish that, two sections of the fibres were coated with amorphous Teflon. By applying the coating, the Q of the relevant modes can be degraded to the desired values and furthermore, the frequencies of these modes can be tuned almost independently with a good accuracy over a wide range. After welding the fibres in the monolithic suspension, a corrective coating was applied to some fibres, to compensate for the frequency spread due to the tension spread of the four fibres within a suspension. We present the method and the results achieved.

  5. Aptamer-based organic-silica hybrid affinity monolith prepared via "thiol-ene" click reaction for extraction of thrombin.

    PubMed

    Wang, Zheng; Zhao, Jin-cheng; Lian, Hong-zhen; Chen, Hong-yuan

    2015-06-01

    A novel strategy for preparing aptamer-based organic-silica hybrid monolithic column was developed via "thiol-ene" click chemistry. Due to the large specific surface area of the hybrid matrix and the simplicity, rapidness and high efficiency of "thiol-ene" click reaction, the average coverage density of aptamer on the organic-silica hybrid monolith reached 420 pmol μL(-1). Human α-thrombin can be captured on the prepared affinity monolithic column with high specificity and eluted by NaClO4 solution. N-p-tosyl-Gly-Pro-Arg p-nitroanilide acetate was used as the sensitive chromogenic substrate of thrombin. The thrombin enriched by this affinity column was detected with a detection of limit of 0.01 μM by spectrophotometry. Furthermore, the extraction recovery of thrombin at 0.15 μM in human serum was 91.8% with a relative standard deviation of 4.0%. These results indicated that "thiol-ene" click chemistry provided a promising technique to immobilize aptamer on organic-inorganic hybrid monolith and the easily-assembled affinity monolithic material could be used to realize highly selective recognition of trace proteins.

  6. Detailed characterization of the kinetic performance of first and second generation silica monolithic columns for reversed-phase chromatography separations.

    PubMed

    Cabooter, Deirdre; Broeckhoven, Ken; Sterken, Roman; Vanmessen, Alison; Vandendael, Isabelle; Nakanishi, Kazuki; Deridder, Sander; Desmet, Gert

    2014-01-17

    The kinetic performance of commercially available first generation and prototype second generation silica monoliths has been investigated for 2.0mm and 3.0-3.2mm inner diameter columns. It is demonstrated that the altered sol-gel process employed for the production of second generation monoliths results in structures with a smaller characteristic size leading to an improved peak shape and higher efficiencies. The permeability of the columns however, decreases significantly due to the smaller throughpore and skeleton sizes. Scanning electron microscopy pictures suggest the first generation monoliths have cylindrical skeleton branches, whereas the second generation monoliths rather have skeleton branches that resemble a single chain of spherical globules. Using recently established correlations for the flow resistance of cylindrical and globule chain type monolithic structures, it is demonstrated that the higher flow resistance of the second generation monoliths can be entirely attributed to their smaller skeleton sizes, which is also evident from the external porosity that is largely the same for both monolith generations (ɛe∼0.65). The recorded van Deemter plots show a clear improvement in efficiency for the second generation monoliths (minimal plate heights of 13.6-14.1μm for the first and 6.5-8.2μm for the second generation, when assessing the plate count using the Foley-Dorsey method). The corresponding kinetic plots, however, indicate that the much reduced permeability of the second generation monoliths results in kinetic performances (time needed to achieve a given efficiency) which are only better than those of the first generation for plate counts up to N∼45,000. For more complex samples (N≥50,000), the first generation monoliths can intrinsically still provide faster analysis due to their high permeability. It is also demonstrated that - despite the improved efficiency of the second generation monoliths in the practical range of separations (N=10

  7. High-performance liquid chromatography separation of unsaturated organic compounds by a monolithic silica column embedded with silver nanoparticles.

    PubMed

    Zhu, Yang; Morisato, Kei; Hasegawa, George; Moitra, Nirmalya; Kiyomura, Tsutomu; Kurata, Hiroki; Kanamori, Kazuyoshi; Nakanishi, Kazuki

    2015-08-01

    The optimization of a porous structure to ensure good separation performances is always a significant issue in high-performance liquid chromatography column design. Recently we reported the homogeneous embedment of Ag nanoparticles in periodic mesoporous silica monolith and the application of such Ag nanoparticles embedded silica monolith for the high-performance liquid chromatography separation of polyaromatic hydrocarbons. However, the separation performance remains to be improved and the retention mechanism as compared with the Ag ion high-performance liquid chromatography technique still needs to be clarified. In this research, Ag nanoparticles were introduced into a macro/mesoporous silica monolith with optimized pore parameters for high-performance liquid chromatography separations. Baseline separation of benzene, naphthalene, anthracene, and pyrene was achieved with the theoretical plate number for analyte naphthalene as 36,000 m(-1). Its separation function was further extended to cis/trans isomers of aromatic compounds where cis/trans stilbenes were chosen as a benchmark. Good separation of cis/trans-stilbene with separation factor as 7 and theoretical plate number as 76,000 m(-1) for cis-stilbene was obtained. The trans isomer, however, is retained more strongly, which contradicts the long- established retention rule of Ag ion chromatography. Such behavior of Ag nanoparticles embedded in a silica column can be attributed to the differences in the molecular geometric configuration of cis/trans stilbenes.

  8. Synthesis and Surface Reactivity of Vinylized Macroporous Silica Monoliths: One-Pot Hybrid versus Postsynthesis Grafting Strategies.

    PubMed

    El-Debs, Racha; Cadoux, Franck; Bois, Laurence; Bonhommé, Anne; Randon, Jérôme; Dugas, Vincent; Demesmay, Claire

    2015-10-27

    Different synthesis routes have been implemented to prepare macroporous monoliths with vinyl pendant groups and micrometric skeletons and through-pore sizes. A standard process combining the synthesis of a widely used (methyltrimethoxysilane/tetramethoxysilane) (MTMS/TMOS) hybrid silica monolith and the postsilanization with vinyltrimethoxysilane (VTMS) was used as reference material (Vgr-MTMS). An alternative "one-pot" procedure was used to obtain vinylized hybrid monoliths. Two VTMS/TMOS hybrid based monoliths were successfully prepared starting from 20% (w) and 80% (w/w) of VTMS, respectively, called 20-VTMS and 80-VTMS. Monoliths were characterized by SEM, nitrogen-adsorption isotherm, and (29)Si MAS NMR spectroscopy. One-pot synthesis allowed to obtain higher vinyl contents (15.9 and 61.5 mol % of Si atoms bonded to vinyl groups respectively for 20-VTMS and 80-VTMS) than for the postgrafted one (7.1%). Accessibility of vinyl groups was determined by the extent of bromination reactions followed by FTIR-ATR spectroscopy. Bromination with reaction yields were higher than 80% for all materials (80%, 85%, and 100% for 80-VTMS, 20-VTMS, and Vgr-MTMS respectively), with no diffusion issues The chemical reactivity of the pendant vinyl groups was investigated through radical-mediated thiol-ene reaction and radical-initiated bisulfite addition. Reaction yields for the two VTMS hybrid monoliths were quite lower (4-6%) than those obtained (about 50%) for the Vgr-MTMS monolith. The difference in reactivity was attributed to the steric hindrance of the vinyl moieties at the surface of hybrid materials. However, the lower reactivity of vinyl groups is compensated by their considerably higher surface density. Thus, hybrid monoliths are advantageous over their grafted counterparts, due to their higher hydrolytic stability and to the greater simplicity of the one-pot process. A chromatographic application exemplifies their interest and performances in separation science. PMID

  9. Synthesis and Surface Reactivity of Vinylized Macroporous Silica Monoliths: One-Pot Hybrid versus Postsynthesis Grafting Strategies.

    PubMed

    El-Debs, Racha; Cadoux, Franck; Bois, Laurence; Bonhommé, Anne; Randon, Jérôme; Dugas, Vincent; Demesmay, Claire

    2015-10-27

    Different synthesis routes have been implemented to prepare macroporous monoliths with vinyl pendant groups and micrometric skeletons and through-pore sizes. A standard process combining the synthesis of a widely used (methyltrimethoxysilane/tetramethoxysilane) (MTMS/TMOS) hybrid silica monolith and the postsilanization with vinyltrimethoxysilane (VTMS) was used as reference material (Vgr-MTMS). An alternative "one-pot" procedure was used to obtain vinylized hybrid monoliths. Two VTMS/TMOS hybrid based monoliths were successfully prepared starting from 20% (w) and 80% (w/w) of VTMS, respectively, called 20-VTMS and 80-VTMS. Monoliths were characterized by SEM, nitrogen-adsorption isotherm, and (29)Si MAS NMR spectroscopy. One-pot synthesis allowed to obtain higher vinyl contents (15.9 and 61.5 mol % of Si atoms bonded to vinyl groups respectively for 20-VTMS and 80-VTMS) than for the postgrafted one (7.1%). Accessibility of vinyl groups was determined by the extent of bromination reactions followed by FTIR-ATR spectroscopy. Bromination with reaction yields were higher than 80% for all materials (80%, 85%, and 100% for 80-VTMS, 20-VTMS, and Vgr-MTMS respectively), with no diffusion issues The chemical reactivity of the pendant vinyl groups was investigated through radical-mediated thiol-ene reaction and radical-initiated bisulfite addition. Reaction yields for the two VTMS hybrid monoliths were quite lower (4-6%) than those obtained (about 50%) for the Vgr-MTMS monolith. The difference in reactivity was attributed to the steric hindrance of the vinyl moieties at the surface of hybrid materials. However, the lower reactivity of vinyl groups is compensated by their considerably higher surface density. Thus, hybrid monoliths are advantageous over their grafted counterparts, due to their higher hydrolytic stability and to the greater simplicity of the one-pot process. A chromatographic application exemplifies their interest and performances in separation science.

  10. Unique Separation Behavior of a C60 Fullerene-Bonded Silica Monolith Prepared by an Effective Thermal Coupling Agent.

    PubMed

    Kubo, Takuya; Murakami, Yoshiki; Tsuzuki, Madoka; Kobayashi, Hiroshi; Naito, Toyohiro; Sano, Tomoharu; Yan, Mingdi; Otsuka, Koji

    2015-12-01

    Herein, we report a newly developed C60 fullerene-bonded silica monolith in a capillary with unique retention behavior due to the structure of C60 fullerene. N-Hydroxysuccinimide (NHS)-conjugated C60 fullerene was successfully synthesized by a thermal coupling agent, perfluorophenyl azide (PFPA), and assigned by spectroscopic analyses. Then, NHS-PFPA-C60 fullerene was attached onto the surface of a silica monolith in a capillary. The capillary provided specific separation ability for polycyclic aromatic hydrocarbons in liquid chromatography by an effective π-π interaction. Furthermore, corannulene, which has a hemispherical structure, was selectively retained in the capillary based on the specific structural recognition due to the spherical C60 fullerene. This is the first report revealing the spherical recognition ability by C60 fullerene in liquid chromatographic separation.

  11. Possibilities of retention prediction in fast gradient liquid chromatography. Part 3: Short silica monolithic columns.

    PubMed

    Jandera, Pavel; Hájek, Tomáš

    2015-09-01

    We studied possibilities of prediction of the gradient elution data for alkylbenzenes, flavones and phenolic acids on two short octadecyl silica gel monolithic columns, namely a Chromolith Flash C18, 25×4.6mm, and a "new generation" Chromolith High Resolution C18, 50×4.6mm, in fast 1-2min gradients. With fixed short gradient times and varying gradient ranges of acetonitrile concentration in water, high flow rates of the mobile phase (3-5mL/min) could be used. The gradient elution data were predicted from four gradient models based on two-parameter and three-parameter isocratic retention equations. Various gradient retention models can be used for prediction of chromatograms and optimization of separation within a fixed gradient time. A two-parameter log-log model introduced in 1974 and a three-parameter model introduced in 1980 provided slightly more accurate prediction than the Linear Solvent Strength (LSS) semi-logarithmic two-parameter model, most frequently used in reversed-phase LC. A three-parameter model introduced in 1978 provided slightly improved accuracy of prediction of gradient data with respect to two-parameter models, in contrast to another, more recent three-parameter empirical model introduced in 2010 (which failed for gradients starting at a non-zero concentration of acetonitrile). Both a longer (5cm) and more efficient Chromolith HR column and a shorter (2.5cm) slightly less efficient Chromolith Flash column provide useful separations in fast gradients (1-2min) at high flow rates (3.5-5mL/min), especially in second dimension of two-dimensional LC×LC, in combination with HILIC separation on monolithic microcolumn in D1. PMID:26239700

  12. Simple practical approach for sample loading prior to DNA extraction using a silica monolith in a microfluidic device.

    PubMed

    Shaw, Kirsty J; Joyce, Domino A; Docker, Peter T; Dyer, Charlotte E; Greenman, John; Greenway, Gillian M; Haswell, Stephen J

    2009-12-01

    A novel DNA loading methodology is presented for performing DNA extraction on a microfluidic system. DNA in a chaotropic salt solution was manually loaded onto a silica monolith orthogonal to the subsequent flow of wash and elution solutions. DNA was successfully extracted from buccal swabs using electro-osmotic pumping (EOP) coupled with in situ reagents contained within a 1.5% agarose gel matrix. The extracted DNA was of sufficient quantity and purity for polymerase chain reaction (PCR) amplification.

  13. Enhancing the separation performance of the first-generation silica monolith using active flow technology: parallel segmented flow mode of operation.

    PubMed

    Soliven, Arianne; Foley, Dominic; Pereira, Luisa; Dennis, Gary R; Shalliker, R Andrew; Cabrera, Karin; Ritchie, Harald; Edge, Tony

    2014-03-21

    Active flow technology (AFT) columns are designed to minimise inefficient flow processes associated with the column wall and radial heterogeneity of the stationary phase bed. This study is the first to investigate AFT on an analytical scale 4.6mm internal diameter first-generation silica monolith. The performance was compared to a conventional first-generation silica monolith and it was observed that the AFT monolith had an increase in efficiency values that ranged from 15 to 111%; the trend demonstrating efficiency gains increasing as the volumetric flow to the detector was decreased, but with no loss in sensitivity.

  14. Hybrid silica monolith for microextraction by packed sorbent to determine drugs from plasma samples by liquid chromatography-tandem mass spectrometry.

    PubMed

    de Souza, Israel D; Domingues, Diego S; Queiroz, Maria E C

    2015-08-01

    The present study (1) reports on the synthesis of two hybrid silica monoliths functionalized with aminopropyl or cyanopropyl groups by the sol-gel process; (2) evaluates these monoliths as selective stationary phase for microextraction by packed sorbent (MEPS) to determine drugs in plasma samples via liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the multiple reactions monitoring (MRM) mode; and (3) discusses important factors related to the optimization of MEPS efficiency as well as the carryover effect. The prepared hybrid silica monoliths consisted of a uniform, porous, and continuous silica monolithic network. The structure of the aminopropyl hybrid silica monolith was more compact than the structure of the cyanopropyl hybrid silica monolith. The Fourier-transform infrared spectroscopy (FTIR) spectra of the hybrid silica monoliths displayed readily identifiable peaks, characteristic of the cyanopropyl and aminopropyl groups. Compared with the aminopropyl hybrid silica phase, the cyanopropyl hybrid silica phase exhibited higher binding capacity for most of the target drugs. The developed method afforded adequate linearity at concentrations ranging from the lower limit of quantification (0.05-1.00 ng mL(-1)) to the upper limit of quantification (40-10,500 ng mL(-1)); the coefficients of determination (r(2)) were higher than 0.9955. The precision of the method presented coefficients of variation (CV) lower than 14%; the relative standard error (RSE) of the accuracy ranged from -12% to 14%. The developed method allowed for simultaneous analysis of five antipsychotics (olanzapine, quetiapine, clozapine, haloperidol, and chlorpromazine) in combination with seven antidepressants (mirtazapine, paroxetine, citalopram, sertraline, imipramine, clomipramine, fluoxetine), two anticonvulsants (carbamazepine and lamotrigine), and two anxiolytics (diazepam and clonazepam) in plasma samples from schizophrenic patients, which should be valuable for therapeutic drug

  15. Behavior of short silica monolithic columns in high pressure gas chromatography.

    PubMed

    Maniquet, Adrien; Bruyer, Nicolas; Raffin, Guy; Baco-Antoniali, Franck; Demesmay, Claire; Dugas, Vincent; Randon, Jérôme

    2016-08-19

    In order to analyze light hydrocarbons mixtures with silica monolithic columns, a conventional gas chromatograph was modified to work with carrier gas pressure as high as 60bar. To understand hydrodynamic flow and retention with short columns (less than 30cm), special attention was required due to the temperature difference between the oven area and the FID detector which contain a significant length of the column. Efficiency and selectivity using various carrier gases (helium, nitrogen and carbon dioxide) at different inlet pressure for different oven temperature were studied. Carrier gas nature was a very significant parameter: on one side, linked to adsorption mechanism for gases like nitrogen and carbon dioxide onto the stationary phase modifying retention and selectivity, on the other side in relation to the minimum theoretical plate height which was as low as 15μm (66 000 platem(-1)) using carbon dioxide as carrier gas. The chromatographic system was then used to separate methane, ethane, ethylene, acetylene, propane, cyclopropane, and butane in less than 30s. PMID:27432790

  16. Rapid determination of amino acids in biological samples using a monolithic silica column.

    PubMed

    Song, Yanting; Funatsu, Takashi; Tsunoda, Makoto

    2012-05-01

    A high-performance liquid chromatography method in which fluorescence detection is used for the simultaneous determination of 21 amino acids is proposed. Amino acids were derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) and then separated on a monolithic silica column (MonoClad C18-HS, 150 mm×3 mm i.d.). A mixture of 25 mM citrate buffer containing 25 mM sodium perchlorate (pH 5.5) and acetonitrile was used as the mobile phase. We found that the most significant factor in the separation was temperature, and a linear temperature gradient from 30 to 49°C was used to control the column temperature. The limits of detection and quantification for all amino acids ranged from 3.2 to 57.2 fmol and 10.8 to 191 fmol, respectively. The calibration curves for the NBD-amino acid had good linearity within the range of 40 fmol to 40 pmol when 6-aminocaproic acid was used as an internal standard. Using only conventional instruments, the 21 amino acids could be analyzed within 10 min. This method was found to be suitable for the quantification of the contents of amino acids in mouse plasma and adrenal gland samples.

  17. Antibody-coupled monolithic silica microtips for highthroughput molecular profiling of circulating exosomes

    PubMed Central

    Ueda, Koji; Ishikawa, Nobuhisa; Tatsuguchi, Ayako; Saichi, Naomi; Fujii, Risa; Nakagawa, Hidewaki

    2014-01-01

    Exosome-mediated signal transportation plays a variety of critical roles in cancer progression and metastasis. From the aspect of cancer diagnosis, circulating exosomes are ideal resources of biomarkers because molecular features of tumor cells are transcribed on them. However, isolating pure exosomes from body fluids is time-consuming and still major challenge to be addressed for comprehensive profiling of exosomal proteins and miRNAs. Here we constructed anti-CD9 antibody-coupled highly porous monolithic silica microtips which allowed automated rapid and reproducible exosome extraction from multiple clinical samples. We applied these tips to explore lung cancer biomarker proteins on exosomes by analyzing 46 serum samples. The mass spectrometric quantification of 1,369 exosomal proteins identified CD91 as a lung adenocarcinoma specific antigen on exosomes, which was further validated with CD9-CD91 exosome sandwich ELISA measuring 212 samples. Our simple device can promote not only biomarker discovery studies but also wide range of omics researches about exosomes. PMID:25167841

  18. Catalyst assisted synthesis of initiator attached silica monolith particles via isocyanate-hydroxyl reaction for production of polystyrene bound chromatographic stationary phase of excellent separation efficiency.

    PubMed

    Ali, Faiz; Kim, Yune Sung; Lee, Jin Wook; Cheong, Won Jo

    2014-01-10

    Dibutyltin dichloride (DBTDC) was used as a catalyst to chemically bind 4-chloromehtylphenylisocynate (4-CPI) to porous monolithic silica particles via isocyanate-hydroxyl reaction, and the reaction product was reacted with sodium diethyldithiocarbamate (SDDC) to yield initiator attached silica monolith particles. Reversible addition-fragmentation transfer (RAFT) polymerization was taken place on them to result in polystyrene attached silica particles that showed excellent separation efficiency when packed in a chromatographic column (1.0 mm × 300 mm). The numbers of theoretical plates (N) of 56,500 is better than those of any commercially available HPLC or UHPLC column yet.

  19. Enantiomeric separation by capillary electrochromatography on a sulfated poly β-cyclodextrin modified silica-based monolith.

    PubMed

    Yuan, Ruijuan; Wang, Yan; Ding, Guosheng

    2010-01-01

    A sulfated poly β-cyclodextrin (SPCD) modified silica-based monolithic column was prepared for enantiomeric separation. First, 2-hydroxy-3-allyloxy-propyl-β-cyclodextrin (allyl-β-CD) was bonded onto a bifunctional reagent 3-(methacryloxy)propyltriethoxysilane (γ-MAPS) modified silica-based monolith through radical polymerization; the column was then sulfated with chlorosulfonic acid. The SPCD chiral stationary phase resolved the boring problem associated with desalting when sulfated CDs were synthesized to act as chiral additives. The inorganic salt in the column introduced during the sulfating process could be easily removed by washing the column with water for some time. Chiral compounds investigated were successfully resolved into their enantiomers on the SPCD modified monolith in the capillary electrochromatography (CEC) mode. Due to the existence of the -SO(3)H group, electrosmotic flow (EOF) was obviously increased, and all of the separations could be carried out in 20 min with only a minor loss in the column efficiency and resolution. PMID:20834124

  20. Textural characterization of native and n-alky-bonded silica monoliths by mercury intrusion/extrusion, inverse size exclusion chromatography and nitrogen adsorption.

    PubMed

    Thommes, M; Skudas, R; Unger, K K; Lubda, D

    2008-05-16

    Native and n-alkyl-bonded (n-octadecyl) monolithic silica rods with mesopores in the range between 10 and 25 nm and macropores in the range between 1.8 and 6.0 microm were examined by mercury intrusion/extrusion, inverse size exclusion chromatography (ISEC) and nitrogen sorption. Our results reveal very good agreement for the mesopore size distribution obtained from nitrogen adsorption (in combination with an advanced NLDFT analysis) and ISEC. Our studies highlight the importance of mercury porosimetry for the assessment of the macropore size distribution and show that mercury porosimetry is the only method which allows obtaining a combined and comprehensive structural characterization of macroporous/mesoporous silica monoliths. Our data clearly confirm that mercury porosimetry hysteresis and entrapment have different origin, and indicate the intrinsic nature of mercury porosimetry hysteresis in these silica monoliths. Within this context some silica monoliths show the remarkable result of no entrapment of mercury after extrusion from the mesopore system (i.e. for the first intrusion/extrusion cycle). The results of a systematic study of the mercury intrusion/extrusion behavior into native silica monoliths and monoliths with bonded n-alkyl groups reveals that the macro (through) pore structure, which controls the mass transfer to and from the mesopores, here mainly controls the entrapment behavior. Our data suggest that mercury intrusion/extrusion porosimetry does not only allow to obtain a comprehensive pore structure analysis, but can also serve as a tool to estimate the mass transport properties of silica monoliths to be employed in liquid-phase separation processes. PMID:18423477

  1. Chip electrochromatographic systems: Novel vertically aligned carbon nanotube and silica monoliths based separations

    NASA Astrophysics Data System (ADS)

    Goswami, Shubhodeep

    2009-12-01

    Miniaturized chemical analysis systems, also know as 'lab-on-a-chip' devices have been rapidly developing over the last decade. Capillary electrochromatography (CEC), a multidimensional separation technique combining capillary electrophoresis (CE) and liquid chromatography (LC) has been of great interest for chip based applications. Preliminary work has been undertaken to develop vertically aligned carbon nanotubes and photopolymerizable silica solgel as novel stationary phase materials for 'chip CEC' separations. Patterned growth of CNTs in a specific location of the channel has been carried out using a solid phase Fe-Al catalyst as well as a vapor deposited ferrocene catalyst. Characterization of the CNT "forests" was achieved using optical microscopy, secondary electron microscopy, high resolution tunneling electron microscopy and Raman spectroscopy. Proof-of-concept applications were demonstrated using reversed phase CEC separations as well as solid phase extraction of a glycosylated protein using concanavilin A immobilized onto the CNT bed. Photopolymerizable silica solgel materials were developed as stationary phase for microfluidic electrochromatographic separations in disposable polydimethylsiloxane (PDMS) chip devices. Effect on morphology and pore size of gels were studied as function of UV and solgel polymerization conditions, porogen, salt additives, geometry and hydrolyzable methoxy-ies. Structural morphologies were studied with Secondary Electron Microscopy (SEM). Pore size and pore volumes were characterized by thermal porometry, nitrogen BET adsorptions and differential scanning calorimetry. Computational fluid dynamics and confocal microscopy tools were employed to study the transport of fluids and model analytes. These investigations were directed towards evolving improved strategies for rinsing of uncrosslinked monomers to form porous monoliths as well as to effect a desired separation under a set of electrochromatograhic conditions

  2. Synthesis of boronate-silica hybrid affinity monolith via a one-pot process for specific capture of glycoproteins at neutral conditions.

    PubMed

    Yang, F; Mao, J; He, X W; Chen, L X; Zhang, Y K

    2013-08-01

    In this study, a boronate-silica hybrid affinity monolith was prepared for specific capture of glycoproteins at neutral pH condition. The monolith was synthesized via a facile one-pot procedure in a stainless steel column by concurrently mixing hydrolyzed alkoxysilanes tetramethoxysilane and vinyltrimethoxysilane, organic monomer 3-acrylamidophenylboronic acid and initiator 2,2'-azobisisobutyronitrile together. The polycondensation of alkoxysilanes and copolymerization of organic monomer and vinyl-silica monolith were carried out successively by reacting at different temperatures. After optimizing the preparation conditions, the resulting hybrid affinity monolith was systematically characterized and exhibited excellent affinity to both cis-diol-containing small molecules and glycoproteins at neutral and physiological pH, including adenosine, horseradish peroxidase, transferrin and ovalbumin. The binding capacity of ovalbumin on monolith was measured to be 2.5 mg g(-1) at pH 7.0. Furthermore, the hybrid affinity monolith was applied to the separation of transferrin from bovine serum sample at a physiological condition. Good repeatability was obtained and the relative standard deviations of retention time were 1.15 and 4.77 % (n = 5) for run-to-run and column-to-column, respectively. PMID:23807307

  3. Histidine-modified organic-silica hybrid monolithic column for mixed-mode per aqueous and ion-exchange capillary electrochromatography.

    PubMed

    Tang, Sheng; Liu, Shujuan; Liang, Xiaojing; Tang, Xiaofen; Wu, Xingcai; Guo, Yong; Liu, Xia; Jiang, Shengxiang

    2015-06-01

    A novel organic-silica hybrid monolith was prepared through the binding of histidine onto the surface of monolithic matrix for mixed-mode per aqueous and ion-exchange capillary electrochromatography. The imidazolium and amino groups on the surface of the monolithic stationary phase were used to generate an anodic electro-osmotic flow as well as to provide electrostatic interaction sites for the charged compounds at low pH. Typical per aqueous chromatographic behavior was observed in water-rich mobile phases. Various polar and hydrophilic analytes were selected to evaluate the characteristics and chromatographic performance of the obtained monolith. Under per aqueous conditions, the mixed-mode mechanism of hydrophobic and ion-exchange interactions was observed and the resultant monolithic column proved to be very versatile for the efficient separations of these polar and hydrophilic compounds (including amides, nucleosides and nucleotide bases, benzoic acid derivatives, and amino acids) in highly aqueous mobile phases. The successful applications suggested that the histidine-modified organic-silica hybrid monolithic column could offer a wide range of retention behaviors and flexible selectivities toward polar and hydrophilic compounds.

  4. Monolithic silica columns functionalized with substituted polyproline-derived chiral selectors as chiral stationary phases for high-performance liquid chromatography.

    PubMed

    Sancho, Raquel; Novell, Arnau; Svec, Frantisek; Minguillón, Cristina

    2014-10-01

    In this study, two polyproline-derived chiral selectors are bonded to monolithic silica gel columns. In spite of high chiral selector coverage, the derivatization was found to have only a slight effect on the hydrodynamics of the mobile phase through the column. The enantioseparation ability of the resulting chiral monolithic columns was evaluated with a series of structurally diverse racemic test compounds. When compared to analogous bead-based chiral stationary phases, higher enantioseparation and broader application domain were observed for monolithic columns. Moreover, the increase in flow rate produces a minor reduction of resolution, which permits to shorten analysis time. Additionally, increased loadability defines chiral polyproline derived monoliths as adequate for preparative chromatography.

  5. Enantiomer separation of acidic chiral compounds on a quinine-silica/zirconia hybrid monolith by capillary electrochromatography.

    PubMed

    Tran, Le Ngoc; Park, Jung Hag

    2015-05-29

    A weak anion-exchanger chiral selector, quinine-incorporated silica/zirconia hybrid monolithic (QUI-S/ZHM) capillary column was prepared by sol-gel technology. The performance of the QUI-S/ZHM column was investigated for enantioresolution of a set of acidic chiral drugs and dinitrobenzoyl (DNB)-amino acids by capillary electrochromatography in aqueous organic mobile phases composed of acetonitrile (ACN) and triethylammonium acetate (TEAA) buffer. Effects of several parameters including the ACN content, concentration and pH of the mobile phase on the chiral separation were examined. Baseline resolutions of all the compounds were obtained in the mobile phase consisting of 70:30 ACN/TEAA (10mM, pH 6) under applied voltage of -10kV at 25°C within 20min.

  6. An electro-osmotic micro-pump based on monolithic silica for micro-flow analyses and electro-sprays.

    PubMed

    Chen, Zilin; Wang, Ping; Chang, Hsueh-Chia

    2005-06-01

    A high-pressure electro-osmotic micro-pump fabricated by a sol-gel process is reported as a fluid-driving unit in a flow-injection analysis (FIA) system. The micro FIA system consists of a monolithic micro-pump on a glass slide (2.5 x 7.5 cm), a micro-injector, and a micro-sensor (2.5 x 1.5 cm). The monolithic silica matrix has a continuous skeleton morphology with micrometer-sized through-pores. The micrometer-size pores with a large negative surface charge density build up a large pressure under a DC electric field to drive fluid through the downstream units. A novel Nafion joint for the downstream cathode eliminates flow into the electrode reservoir and further enhances pressure build-up. The measured pump-pressure curve indicated a maximum pressure of 0.4 MPa at flow rate of 0.4 microL min(-1) at 6 kV. Despite the large voltage, the small current transmission area through the monolith produced a negligible current (less than 100 microA) that did not generate bubbles or ion contaminants. The flow rate can be precisely controlled in the range 200 nL to 2.5 microL min(-1) by varying the voltage from 1 to 6 kV. The high pump pressure and the large current-free DC field also enabled the pump to act as an electro-spray interface with a downstream analytical instrument.

  7. C₁₈-bound porous silica monolith particles as a low-cost high-performance liquid chromatography stationary phase with an excellent chromatographic performance.

    PubMed

    Ali, Faiz; Cheong, Won Jo

    2014-12-01

    Ground porous silica monolith particles with an average particle size of 2.34 μm and large pores (363 Å) exhibiting excellent chromatographic performance have been synthesized on a relatively large scale by a sophisticated sol-gel procedure. The particle size distribution was rather broad, and the d(0.1)/d(0.9) ratio was 0.14. The resultant silica monolith particles were chemically modified with chlorodimethyloctadecylsilane and end-capped with a mixture of hexamethyldisilazane and chlorotrimethylsilane. Very good separation efficiency (185,000/m) and chromatographic resolution were achieved when the C18 -bound phase was evaluated for a test mixture of five benzene derivatives after packing in a stainless-steel column (1.0 mm × 150 mm). The optimized elution conditions were found to be 70:30 v/v acetonitrile/water with 0.1% trifluoroacetic acid at a flow rate of 25 μL/min. The column was also evaluated for fast analysis at a flow rate of 100 μL/min, and all the five analytes were eluted within 3.5 min with reasonable efficiency (ca. 60,000/m) and resolution. The strategy of using particles with reduced particle size and large pores (363 Å) combined with C18 modification in addition to partial-monolithic architecture has resulted in a useful stationary phase (C18 -bound silica monolith particles) of low production cost showing excellent chromatographic performance.

  8. Tailoring the macroporous structure of monolithic silica-based capillary columns with potential for liquid chromatography.

    PubMed

    Laschober, Stefan; Sulyok, Michael; Rosenberg, Erwin

    2007-03-01

    The present work aims at the optimisation of the synthesis of methyl-silsesquioxane monolithic capillary columns using a sol-gel based protocol. The influence of reaction conditions such as temperature, reaction mixture composition and catalyst concentration has been examined. The morphology of the products was studied by scanning electron microscopy and nitrogen adsorption. Monolithic capillary columns were obtained with a skeleton-like structure with open pores. Pore diameters vary from 0.8 to 15 microm, diameters of the xerogel network vary from 0.4 to 12 microm, respectively. Specific surface areas up to 334 m2/g have been observed, however, many materials did not possess areas above few m2/g which represents the limit of detection of the nitrogen porosimetry measurements. Excellent adhesion to the capillary wall was observed in all cases, and drying was possible at ambient conditions without the formation of cracks. PMID:17241639

  9. Continuous laser irradiation under ambient conditions: A simple way for the space-selective growth of gold nanoparticles inside a silica monolith

    SciTech Connect

    El Hamzaoui, Hicham; Bernard, Remy; Chahadih, Abdallah; Chassagneux, Fernand; Bois, Laurence; Capoen, Bruno; Bouazaoui, Mohamed

    2011-09-15

    Highlights: {yields} Visible continuous laser direct-write gold nanoparticles inside a silica monolith. {yields} The presence of the additive (Na{sub 2}CO{sub 3}) is not necessary to the growth of gold nanoparticles. {yields} A simple heat treatment leads to precipitation of gold nanoparticles inside the silica matrices with, or without, the additive. {yields} The local precipitation of gold nanoparticles by continuous photo-irradiation occurs following a photo-thermal activated mechanism. -- Abstract: Thanks to the potential and various applications of metal-dielectric nanocomposites, their syntheses constitute an interesting subject in material research. In this work, we demonstrate the achievement of gold nanocrystals growth through a visible and continuous laser irradiation. The in situ and direct space-selective generation of metallic nanoparticles is localized under the surface within transparent silica monoliths. For that purpose, the porous silica monoliths are prepared using a sol-gel route and post-doped with gold precursors before the irradiation. The presence of Au nanoparticles inside the irradiated areas was evidenced using absorption spectroscopy, X-ray diffraction analysis and transmission electron microscopy. The comparison between the results obtained after a laser irradiation and by a simple heat-treatment reveals that the local precipitation of gold nanoparticles by continuous photo-irradiation occurs following a photo-thermal activated mechanism.

  10. Temperature Effects on Agrobacterium Phytochrome Agp1

    PubMed Central

    Njimona, Ibrahim; Lamparter, Tilman

    2011-01-01

    Phytochromes are widely distributed biliprotein photoreceptors with a conserved N-terminal chromophore-binding domain. Most phytochromes bear a light-regulated C-terminal His kinase or His kinase-like region. We investigated the effects of light and temperature on the His kinase activity of the phytochrome Agp1 from Agrobacterium tumefaciens. As in earlier studies, the phosphorylation activity of the holoprotein after far-red irradiation (where the red-light absorbing Pr form dominates) was stronger than that of the holoprotein after red irradiation (where the far red-absorbing Pfr form dominates). Phosphorylation activities of the apoprotein, far red-irradiated holoprotein, and red-irradiated holoprotein decreased when the temperature increased from 25°C to 35°C; at 40°C, almost no kinase activity was detected. The activity of a holoprotein sample incubated at 40°C was nearly completely restored when the temperature returned to 25°C. UV/visible spectroscopy indicated that the protein was not denatured up to 45°C. At 50°C, however, Pfr denatured faster than the dark-adapted sample containing the Pr form of Agp1. The Pr visible spectrum was unaffected by temperatures of 20–45°C, whereas irradiated samples exhibited a clear temperature effect in the 30–40°C range in which prolonged irradiation resulted in the photoconversion of Pfr into a new spectral species termed Prx. Pfr to Prx photoconversion was dependent on the His-kinase module of Agp1; normal photoconversion occurred at 40°C in the mutant Agp1-M15, which lacks the C-terminal His-kinase module, and in a domain-swap mutant in which the His-kinase module of Agp1 is replaced by the His-kinase/response regulator module of the other A. tumefaciens phytochrome, Agp2. The temperature-dependent kinase activity and spectral properties in the physiological temperature range suggest that Agp1 serves as an integrated light and temperature sensor in A. tumefaciens. PMID:22043299

  11. Fast, noninvasive and simultaneous near-infrared spectroscopic characterisation of physicochemical stationary phases' properties: from silica particles towards monoliths.

    PubMed

    Petter, Christine H; Heigl, Nico; Bonn, Günther K; Huck, Christian W

    2008-08-01

    The design of novel stationary phases is a permanent demanding challenge in chromatographic separation science to enable analysis with enhanced selectivity, specificity and speed. Therefore, the characterisation of chemical and physical properties is next to calculation of chromatographic parameters essential. Conventionally, chemical parameters including surface coverage are determined by burning combustion or frontal analysis, physical parameters including particle size, pore size, pore volume and surface area are determined by SEM, mercury intrusion porosimetry (MIP) and Brunauer-Emmett-Teller (BET). All these methods are time consuming, invasive and require besides special equipment some special trained laboratory staff. Therefore, we introduced near-infrared spectroscopy (NIRS) as a noninvasive, easy-to-handle technology with wavenumber ranging from 4000 to 10,000 cm(-1) enabling analysis within only a few seconds at higher precision than the conventional methods. Investigated materials comprise porous and nonporous silica gel, carbon-based nanomaterials (fullerenes), polymer beads and monoliths. Different carriers themselves and their kind of derivatisations (RP, normal-phase, ion-exchanger, IMAC (immobilised metal affinity chromatography), affinity) can be determined by applying principal component analysis (PCA) of recorded spectra. Partial least square regression (PLSR) enables the determination of particle size, pore size, pore volume, porosity, total porosity and surface area with one single measurement. For the optimised design of well-defined polymer beads and monoliths, real-time in situ monitoring to control, e. g. particle and pore sizes as well as monomer content during the polymerisation process, can be extremely helpful. In this article, the advantages of this fast, noninvasive high-throughput NIRS methods are summarised, discussed in detail and different applications of the individual characterised materials are shown.

  12. Preparation and evaluation of o-phenanthroline immobilized on a hybrid silica monolith modified with ionic liquids for reversed-phase pressurized capillary electrochromatography.

    PubMed

    Qin, Wenfei; Lü, Haixia; Xie, Zenghong

    2014-12-01

    A novel o-phenanthroline-immobilized ionic-liquid-modified hybrid monolith for capillary electrochromatography was synthesized based on chloropropyl-silica, which was prepared by the in situ polymerization of tetramethoxysilane and 3-chloropropyltrimethoxysilane via a sol-gel process. The morphology of the hybrid monolith was characterized by scanning electron microscopy, and relatively stable anodic electroosmotic flow was observed under a broad pH ranged from pH 3.0 to 9.0. The separation mechanism was investigated by separating four neutral molecules (toluene, dimethylformamide, formamide, and thiourea). The obtained hybrid monolith possessed an obviously reversed-phase retention mechanism, but when the acetonitrile content in the mobile phase was >90% v/v, a weak hydrophilic mechanism was observed on the resultant o-phenanthroline-modified chloropropyl-silica hybrid monolith. The reproducibility of the column was also investigated by measuring relative standard deviations of the migration time for four neutral molecules. Relative standard deviations of run to run (n = 3), day to day (n = 3), and column to column (n = 3) were in the range of 0.4-0.7, 0.9-2.1, and 1.4-3.3%, respectively. Basic separations of various polar analytes including phenols and aromatic amines were successfully achieved.

  13. Application of a Burkholderia cepacia lipase-immobilized silica monolith to batch and continuous biodiesel production with a stoichiometric mixture of methanol and crude Jatropha oil

    PubMed Central

    2011-01-01

    Background The enzymatic production of biodiesel through alcoholysis of triglycerides has become more attractive because it shows potential in overcoming the drawbacks of chemical processes. In this study, we investigate the production of biodiesel from crude, non-edible Jatropha oil and methanol to characterize Burkholderia cepacia lipase immobilized in an n-butyl-substituted hydrophobic silica monolith. We also evaluate the performance of a lipase-immobilized silica monolith bioreactor in the continuous production of biodiesel. Results The Jatropha oil used contained 18% free fatty acids, which is problematic in a base-catalyzed process. In the lipase-catalyzed reaction, the presence of free fatty acids made the reaction mixture homogeneous and allowed bioconversion to proceed to 90% biodiesel yield after a 12 hour reaction time. The optimal molar ratio of methanol to oil was 3.3 to 3.5 parts methanol to one part oil, with water content of 0.6% (w/w). Further experiments revealed that B. cepacia lipase immobilized in hydrophobic silicates was sufficiently tolerant to methanol, and glycerol adsorbed on the support disturbed the reaction to some extent in the present reaction system. The continuous production of biodiesel was performed at steady state using a lipase-immobilized silica monolith bioreactor loaded with 1.67 g of lipase. The yield of 95% was reached at a flow rate of 0.6 mL/h, although the performance of the continuous bioreactor was somewhat below that predicted from the batch reactor. The bioreactor was operated successfully for almost 50 days with 80% retention of the initial yield. Conclusions The presence of free fatty acids originally contained in Jatropha oil improved the reaction efficiency of the biodiesel production. A combination of B. cepacia lipase and its immobilization support, n-butyl-substituted silica monolith, was effective in the production of biodiesel. This procedure is easily applicable to the design of a continuous flow

  14. Synthesis of robust hierarchical silica monoliths by surface-mediated solution/precipitation reactions over different scales: designing capillary microreactors for environmental applications.

    PubMed

    García-Aguilar, J; Miguel-García, I; Berenguer-Murcia, Á; Cazorla-Amorós, D

    2014-12-24

    A synthetic procedure to prepare novel materials (surface-mediated fillings) based on robust hierarchical monoliths is reported. The methodology includes the deposition of a (micro- or mesoporous) silica thin film on the support followed by growth of a porous monolithic SiO2 structure. It has been demonstrated that this synthesis is viable for supports of different chemical nature with different inner diameters without shrinkage of the silica filling. The formation mechanism of the surface-mediated fillings is based on a solution/precipitation process and the anchoring of the silica filling to the deposited thin film. The interaction between the two SiO2 structures (monolith and thin film) depends on the porosity of the thin film and yields composite materials with different mechanical stability. By this procedure, capillary microreactors have been prepared and have been proved to be highly active and selective in the total and preferential oxidation of carbon monoxide (TOxCO and PrOxCO).

  15. Preparation of organic-inorganic hybrid silica monolith with octyl and sulfonic acid groups for capillary electrochromatograhpy and application in determination of theophylline and caffeine in beverage.

    PubMed

    Chen, Ming-Luan; Zheng, Ming-Ming; Feng, Yu-Qi

    2010-05-21

    An organic-inorganic hybrid silica monolithic column with octyl and sulfonic acid groups has been prepared by sol-gel technique for capillary electrochromatograhpy. The structure of hybrid monolith was optimized by changing the composition of tetraethoxysilane (TEOS), octyltriethoxysilane (C(8)-TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) in the mixture of precursors. Then, the obtained hybrid monolith was oxidized using hydrogen peroxide (30%, w/w) to yield sulfonic acid groups. The sulfonic acid group, which served as strong cation-exchanger, dominated the charge on the surface of the capillary column and generated stable electroosmotic flow (EOF) in a wide range of pH. The monolithic column was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and elemental analysis (EA), and the performance of column was evaluated in detail by separating different kinds of compounds with column efficiency up to 155,000 plates/m for thiourea. In addition, this monolithic column was also applied in the analysis of theophylline (TP) and caffeine (CA) in beverages. The detection limits were 0.39 and 0.48 microg/mL for theophylline and caffeine, respectively. The method reproducibility was tested by evaluating the intra- and inter-day precisions, and relative standard deviations of less than 3.9 and 8.4%, respectively, were obtained. Recoveries of compounds from spiked beverage samples ranged from 87.2 to 105.2%.

  16. Violin mode amplitude glitch monitor for the presence of excess noise on the monolithic silica suspensions of GEO 600

    NASA Astrophysics Data System (ADS)

    Sorazu, B.; Strain, K. A.; Heng, I. S.; Kumar, R.

    2010-08-01

    Non-Gaussian features of data from gravitational wave detectors are of interest as unpredictable 'glitches' limit the sensitivity of searches for many kinds of signal. We consider events due to non-random excitations of the test masses and their suspension fibres. These events could, for example, be related to acoustic emissions in the fibres due to the presence and propagation of cracks or another type of structural perturbation, and they would generate excess noise above the Gaussian background, which matches the level expected due to thermal noise. We look for excess noise in the fundamental violin modes of the monolithic silica suspension fibres of GEO 600. We describe the algorithm used to monitor the violin mode amplitude for glitches, present our results and consider how these may be applied to advanced detectors. The conclusion of our analysis is that no excess noise above what was considered to be thermal noise was observed for several days of h(t) data analysed at the frequency of the selected violin modes.

  17. Silica-based monolithic column with evaporative light scattering detector for HPLC analysis of bacosides and apigenin in Bacopa monnieri.

    PubMed

    Bhandari, Pamita; Kumar, Neeraj; Singh, Bikram; Singh, Virendra; Kaur, Inderjeet

    2009-08-01

    A high performance liquid chromatographic method using a silica-based monolithic column coupled with evaporative light scattering detector (HPLC-ELSD) was developed and validated for simultaneous quantification of bacosides (bacoside A, bacopaside I, bacoside A(3), bacopaside II, bacopaside X, bacopasaponin C) and apigenin in Bacopa monnieri. The chromatographic resolution was achieved on a Chromolith RP-18 (100x4.6 mm) column with acetonitrile/water (30:70) as mobile phase in isocratic elution at a flow rate of 0.7 mL/min. The drift tube temperature of the ELSD was set to 95 degrees C, and the nitrogen flow rate was 2.0 SLM (standard liter per minute). The calibration curves revealed a good linear relationship (r(2) > 0.9988) within the test ranges. The detection limits (S/N = 3) and the quantification limits (S/N = 10) for the compounds were in the range of 0.54-6.06 and 1.61-18.78 microg/mL, respectively. Satisfactory average recovery was observed in the range of 95.8-99.0%. The method showed good reproducibility for the quantification of these compounds in B. monnieri with intra- and inter-day precision of less than 0.69 and 0.67%, respectively. The validated method was successfully applied to quantify analytes in nine accessions of B. monnieri and thus provides a new basis for overall quality assessment of B. monnieri.

  18. Nanogold-Decorated Silica Monoliths as Highly Efficient Solid-Phase Adsorbent for Ultratrace Mercury Analysis in Natural Waters.

    PubMed

    Huber, Jessica; Heimbürger, Lars-Eric; Sonke, Jeroen E; Ziller, Sebastian; Lindén, Mika; Leopold, Kerstin

    2015-11-01

    We propose a novel analytical method for mercury (Hg) trace determination based on direct Hg preconcentration from aqueous solution onto a gold nanoparticle-decorated silica monolith (AuNP@SiO2). Detection of Hg is performed after thermal desorption by means of atomic fluorescence spectrometry. This new methodology benefits from reagent-free, time- and cost-saving procedure, due to most efficient solid-phase adsorbent and results in high sensitive quantification. The excellent analytical performance of the whole procedure is demonstrated by a limit of detection as low as 1.31 ng L(-1) for only one-min accumulation duration. A good reproducibility with standard deviations ≤5.4% is given. The feasibility of the approach in natural waters was confirmed by a recovery experiment in spiked seawater with a recovery rate of 101%. Moreover, the presented method was validated through reference analysis of a submarine groundwater discharge sample by cold vapor-atomic fluorescence spectrometry resulting in a very good agreement of the found values. Hence the novel method is a very promising new tool for low-level Hg monitoring in natural waters providing easy-handling on-site preconcentration, reagent-free stabilization as well as reagent-free, highly sensitive detection.

  19. Ion chromatographic determination of hydroxide ion on monolithic reversed-phase silica gel columns coated with nonionic and cationic surfactants.

    PubMed

    Xu, Qun; Mori, Masanobu; Tanaka, Kazuhiko; Ikedo, Mikaru; Hu, Wenzhi; Haddad, Paul R

    2004-07-01

    The determination of hydroxide by ion chromatography (IC) is demonstrated using a monolithic octadecylsilyl (ODS)-silica gel column coated first with a nonionic surfactant (polyoxyethylene (POE)) and then with a cationic surfactant (cetyltrimethylammonium bromide (CTAB)). This stationary phase, when used in conjunction with a 10 mmol/l sodium sulfate eluent at pH 8.2, was found to be suitable for the rapid and efficient separation of hydroxide from some other anions, based on a conventional ion-exchange mechanism. The peak directions and detection responses for these ions were in agreement with their known limiting equivalent ionic conductance values. Under these conditions, a linear calibration plot was obtained for hydroxide ion over the range 16 micromol/l to 15 mmol/l, and the detection limit determined at a signal-to-noise ratio of 3 was 6.4 micromol/l. The double-coated stationary phase described above was shown to be superior to a single coating of cetyltrimethylammonium bromide alone, in terms of separation efficiency and stability of the stationary phase. A range of samples comprising solutions of some strong and weak bases was analyzed by the proposed method and the results obtained were in good agreement with those obtained by conventional potentiometric pH measurement.

  20. Surface modified aerogel monoliths

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas (Inventor); Johnston, James C. (Inventor); Kuczmarski, Maria A. (Inventor); Meador, Mary Ann B. (Inventor)

    2013-01-01

    This invention comprises reinforced aerogel monoliths such as silica aerogels having a polymer coating on its outer geometric surface boundary, and to the method of preparing said aerogel monoliths. The polymer coatings on the aerogel monoliths are derived from polymer precursors selected from the group consisting of isocyanates as a precursor, precursors of epoxies, and precursors of polyimides. The coated aerogel monoliths can be modified further by encapsulating the aerogel with the polymer precursor reinforced with fibers such as carbon or glass fibers to obtain mechanically reinforced composite encapsulated aerogel monoliths.

  1. Development of a bi-functional silica monolith for electro-osmotic pumping and DNA clean-up/extraction using gel-supported reagents in a microfluidic device.

    PubMed

    Oakley, Jennifer A; Shaw, Kirsty J; Docker, Peter T; Dyer, Charlotte E; Greenman, John; Greenway, Gillian M; Haswell, Stephen J

    2009-06-01

    A silica monolith used to support both electro-osmotic pumping (EOP) and the extraction/elution of DNA coupled with gel-supported reagents is described. The benefits of the combined EOP extraction/elution system were illustrated by combining DNA extraction and gene amplification using the polymerase chain reaction (PCR) process. All the reagents necessary for both processes were supported within pre-loaded gels that allow the reagents to be stored at 4 degrees C for up to four weeks in the microfluidic device. When carrying out an analysis the crude sample only needed to be hydrodynamically introduced into the device which was connected to an external computer controlled power supply via platinum wire electrodes. DNA was extracted with 65% efficiency after loading lysed cells onto a silica monolith. Ethanol contained within an agarose gel matrix was then used to wash unwanted debris away from the sample by EOP (100 V cm(-1) for 5 min). The retained DNA was subsequently eluted from the monolith by water contained in a second agarose gel, again by EOP using an electric field of 100 V cm(-1) for 5 min, and transferred into the PCR reagent containing gel. The eluted DNA in solution was successfully amplified by PCR, confirming that the concept of a complete self-contained microfluidic device could be realised for DNA sample clean up and amplification, using a simple pumping and on-chip reagent storage methodology.

  2. Preparation of high efficiency and low carry-over immobilized enzymatic reactor with methacrylic acid-silica hybrid monolith as matrix for on-line protein digestion.

    PubMed

    Yuan, Huiming; Zhang, Lihua; Zhang, Yukui

    2014-12-01

    In this work, a novel kind of organic-silica hybrid monolith based immobilized enzymatic reactor (IMER) was developed. The monolithic support was prepared by a single step "one-pot" strategy via the polycondensation of tetramethoxysilane and vinyltrimethoxysilane and in situ copolymerization of methacrylic acid and vinyl group on the precondensed siloxanes with ammonium persulfate as the thermal initiator. Subsequently, the monolith was activated by N-(3-dimethylaminopropyl) - N'-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS), followed by the modification of branched polyethylenimine (PEI) to improve the hydrophilicity. Finally, after activated by EDC and NHS, trypsin was covalently immobilized onto the monolithic support. The performance of such a microreactor was evaluated by the in sequence digestion of bovine serum albumin (BSA) and myoglobin, followed by MALDI-TOF-MS analysis. Compared to those obtained by traditional in-solution digestion, not only higher sequence coverages for BSA (74±1.4% vs. 59.5±2.7%, n=6) and myoglobin (93±3% vs. 81±4.5%, n=6) were obtained, but also the digestion time was shortened from 24h to 2.5 min, demonstrating the high digestion efficiency of such an IMER. The carry-over of these two proteins on the IMER was investigated, and peptides from BSA could not be found in mass spectrum of myoglobin digests, attributed to the good hydrophilicity of our developed monolithic support. Moreover, the dynamic concentration range for protein digestion was proved to be four orders of magnitude, and the IMER could endure at least 7-day consecutive usage. Furthermore, such an IMER was coupled with nano-RPLC-ESI/MS/MS for the analysis of extracted proteins from Escherichia coli. Compared to formerly reported silica hybrid monolith based IMER and the traditional in-solution counterpart, by our developed IMER, although the identified protein number was similar, the identified distinct peptide number was improved by 7% and 25% respectively

  3. Preparation of high efficiency and low carry-over immobilized enzymatic reactor with methacrylic acid-silica hybrid monolith as matrix for on-line protein digestion.

    PubMed

    Yuan, Huiming; Zhang, Lihua; Zhang, Yukui

    2014-12-01

    In this work, a novel kind of organic-silica hybrid monolith based immobilized enzymatic reactor (IMER) was developed. The monolithic support was prepared by a single step "one-pot" strategy via the polycondensation of tetramethoxysilane and vinyltrimethoxysilane and in situ copolymerization of methacrylic acid and vinyl group on the precondensed siloxanes with ammonium persulfate as the thermal initiator. Subsequently, the monolith was activated by N-(3-dimethylaminopropyl) - N'-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS), followed by the modification of branched polyethylenimine (PEI) to improve the hydrophilicity. Finally, after activated by EDC and NHS, trypsin was covalently immobilized onto the monolithic support. The performance of such a microreactor was evaluated by the in sequence digestion of bovine serum albumin (BSA) and myoglobin, followed by MALDI-TOF-MS analysis. Compared to those obtained by traditional in-solution digestion, not only higher sequence coverages for BSA (74±1.4% vs. 59.5±2.7%, n=6) and myoglobin (93±3% vs. 81±4.5%, n=6) were obtained, but also the digestion time was shortened from 24h to 2.5 min, demonstrating the high digestion efficiency of such an IMER. The carry-over of these two proteins on the IMER was investigated, and peptides from BSA could not be found in mass spectrum of myoglobin digests, attributed to the good hydrophilicity of our developed monolithic support. Moreover, the dynamic concentration range for protein digestion was proved to be four orders of magnitude, and the IMER could endure at least 7-day consecutive usage. Furthermore, such an IMER was coupled with nano-RPLC-ESI/MS/MS for the analysis of extracted proteins from Escherichia coli. Compared to formerly reported silica hybrid monolith based IMER and the traditional in-solution counterpart, by our developed IMER, although the identified protein number was similar, the identified distinct peptide number was improved by 7% and 25% respectively

  4. MicroSPE-nanoLC-ESI-MS/MS Using 10-μm-i.d. Silica-Based Monolithic Columns for Proteomics

    SciTech Connect

    Luo, Quanzhou; Page, Jason S.; Tang, Keqi; Smith, Richard D.

    2007-01-01

    Silica-based monolithic narrow bore capillary columns (25 cm x 10 µm i.d.) with an integrated nanoESI emitter has been developed to provide high quality and robust microSPE-nanoLC-ESI-MS analyses. The integrated nanoESI emitter adds no dead volume to the LC separation, allowing stable electrospray performance to be obtained at flow rates of ~10 nL/min. In an initial application we identified 5510 unique peptides covering 1443 distinct Shewanella oneidensis proteins from a 300 ng tryptic digest sample in a single 4-h LC-MS/MS analysis using a linear ion trap MS (LTQ). We found the use of an integrated monolithic ESI emitter provided enhanced resistance to clogging and good run-to-run reproducibility.

  5. One-pot preparation of a mixed-mode organic-silica hybrid monolithic capillary column and its application in determination of endogenous gibberellins in plant tissues.

    PubMed

    Zhang, Zheng; Hao, Yan-Hong; Ding, Jun; Xu, Sheng-Nan; Yuan, Bi-Feng; Feng, Yu-Qi

    2015-10-16

    A newly improved one-pot method, based on "thiol-ene" click chemistry and sol-gel approach in microemulsion system, was developed for the preparation of C8/PO(OH)2-silica hybrid monolithic capillary column. The prepared monolith possesses large specific surface area, narrow mesopore size distribution and high column efficiency. The monolithic column was demonstrated to have cation exchange/reversed-phase (CX/RP) mixed-mode retention for analytes on nano-liquid chromatography (nano-LC). On the basis of the developed nano-LC system with MS detector coupled to pipette tip solid phase extraction (PT-SPE) and derivatization process, we then realized simultaneous determination of 10 gibberellins (GAs) with low limits of detection (LODs, 0.003-0.025 ng/mL). Furthermore, 6 endogenous GAs in only 5mg rice leaves (fresh weight) were successfully detected and quantified. The developed PT-SPE-nano-LC-MS strategy may offer promising applications in the determination of low abundant bioactive molecules from complex matrix.

  6. Effect of the presence of an ordered micro-pillar array on the formation of silica monoliths.

    PubMed

    Detobel, Frederik; Eghbali, Hamed; De Bruyne, Selm; Terryn, Herman; Gardeniers, Han; Desmet, Gert

    2009-10-30

    We report on the synthesis of siloxane-based monoliths in the presence of a two-dimensional, perfectly ordered array of micro-pillars. Both methyltrimethoxysilane- and tetramethoxysilane-based monoliths were considered. The obtained structures were analyzed using scanning-electron microscopy and can be explained from the general theory of surface-directed phase separation in confined spaces. The formed structures are to a large extent nearly exclusively determined by the ratio between the bulk domain size of the monolith on the one hand and the distance between the micro-pillars on the other hand. When this ratio is small, the presence of the pillars has nearly no effect on the morphology of the produced monoliths. However, when the ratio approaches unity and ascends above it, some new types of monolith morphologies are induced, two of which appear to have interesting properties for use as novel chromatographic supports. One of these structures (obtained when the domain size/inter-pillar distance ratio is around unity) is a 3D network of linear interconnections between the pillars, organized such that all skeleton branches are oriented perpendicular to the micro-pillar surface. A second interesting structure is obtained at even higher values of the domain size/inter-pillar distance ratio. In this case, each individual micro-pillar is uniformly coated with a mesoporous shell.

  7. Simultaneous determination of dibucaine and naphazoline in human serum by monolithic silica spin column extraction and liquid chromatography-mass spectrometry.

    PubMed

    Saito, Takeshi; Morita, Seiji; Kishiyama, Izumi; Miyazaki, Shota; Nakamoto, Akihiro; Nishida, Manami; Namera, Akira; Nagao, Masataka; Inokuchi, Sadaki

    2008-09-01

    A simple, sensitive, and specific liquid chromatography-mass spectrometry (LC-MS) method for simultaneous determination of dibucaine and naphazoline from serum was developed and validated. The extraction procedure was performed using a monolithic silica spin column. Chromatographic separation of dibucaine and naphazoline was achieved on a C(18) reverse phase column with a mobile phase gradient (mobile phase A: 10 mM ammonium formate and mobile phase B: acetonitrile) at a flow rate of 0.2 mL/min. LC-MS was operated under the selective ion monitoring mode using the electrospray ionization technique in the positive mode. The retention times for naphazoline, dibucaine, and the internal standard (IS) were 6.7, 7.8, and 8.0 min, respectively. A linear graph was obtained for dibucaine and naphazoline with correlation coefficients >0.998 for all analytes by this method. The limit of quantification of dibucaine and naphazoline was 10 and 25 ng/mL, respectively. The mean recoveries were greater than 70%. Both compounds were stable under conditions of short-term storage, long-term storage as well as after freeze-thaw cycles. Monolithic spin column extraction and LC-MS analysis enabled the separation of dibucaine and naphazoline within 20 min.

  8. Comprehensive profiling of ribonucleosides modification by affinity zirconium oxide-silica composite monolithic column online solid-phase microextraction - Mass spectrometry analysis.

    PubMed

    Jiang, Han-Peng; Chu, Jie-Mei; Lan, Meng-Dan; Liu, Ping; Yang, Na; Zheng, Fang; Yuan, Bi-Feng; Feng, Yu-Qi

    2016-09-01

    More than 140 modified ribonucleosides have been identified in RNA. Determination of endogenous modified ribonucleosides in biological fluids may serve as non-invasive disease diagnostic strategy. However, detection of the modified ribonucleosides in biological fluids is challenging, especially for the low abundant modified ribonucleosides due to the serious matrix interferences of biological fluids. Here, we developed a facile preparation strategy and successfully synthesized zirconium oxide-silica (ZrO2/SiO2) composite capillary monolithic column that exhibited excellent performance for the selective enrichment of cis-diol-containing compounds. Compared with the boronate-based affinity monolith, the ZrO2/SiO2 monolith showed ∼2 orders of magnitude higher extraction capacity and can be used under physiological pH (pH 6.5-7.5). Using the prepared ZrO2/SiO2 composite monolith as the trapping column and reversed-phase C18 column as the analytical column, we further established an online solid-phase microextraction (SPME) in combination with liquid chromatography-mass spectrometry (online SPME-LC-MS/MS) analysis for the comprehensive profiling of ribonucleosides modification in human urine. Our results showed that 68 cis-diol-containing ribosylated compounds were identified in human urine, which is, to the best of our knowledge, the highest numbers of cis-diol-containing compounds were determined in a single analysis. It is worth noting that four modified ribonucleosides were discovered in the human urine for the first time. In addition, the quantification results from the pooled urine samples showed that compared to healthy controls, the contents of sixteen ribose conjugates in the urine of gastric cancer, eleven in esophagus cancer and seven in lymphoma increased more than two folds. Among these ribose conjugates, four ribose conjugates increased more than two folds in both gastric cancer and esophagus cancer; three ribose conjugates increased more than two

  9. Comprehensive profiling of ribonucleosides modification by affinity zirconium oxide-silica composite monolithic column online solid-phase microextraction - Mass spectrometry analysis.

    PubMed

    Jiang, Han-Peng; Chu, Jie-Mei; Lan, Meng-Dan; Liu, Ping; Yang, Na; Zheng, Fang; Yuan, Bi-Feng; Feng, Yu-Qi

    2016-09-01

    More than 140 modified ribonucleosides have been identified in RNA. Determination of endogenous modified ribonucleosides in biological fluids may serve as non-invasive disease diagnostic strategy. However, detection of the modified ribonucleosides in biological fluids is challenging, especially for the low abundant modified ribonucleosides due to the serious matrix interferences of biological fluids. Here, we developed a facile preparation strategy and successfully synthesized zirconium oxide-silica (ZrO2/SiO2) composite capillary monolithic column that exhibited excellent performance for the selective enrichment of cis-diol-containing compounds. Compared with the boronate-based affinity monolith, the ZrO2/SiO2 monolith showed ∼2 orders of magnitude higher extraction capacity and can be used under physiological pH (pH 6.5-7.5). Using the prepared ZrO2/SiO2 composite monolith as the trapping column and reversed-phase C18 column as the analytical column, we further established an online solid-phase microextraction (SPME) in combination with liquid chromatography-mass spectrometry (online SPME-LC-MS/MS) analysis for the comprehensive profiling of ribonucleosides modification in human urine. Our results showed that 68 cis-diol-containing ribosylated compounds were identified in human urine, which is, to the best of our knowledge, the highest numbers of cis-diol-containing compounds were determined in a single analysis. It is worth noting that four modified ribonucleosides were discovered in the human urine for the first time. In addition, the quantification results from the pooled urine samples showed that compared to healthy controls, the contents of sixteen ribose conjugates in the urine of gastric cancer, eleven in esophagus cancer and seven in lymphoma increased more than two folds. Among these ribose conjugates, four ribose conjugates increased more than two folds in both gastric cancer and esophagus cancer; three ribose conjugates increased more than two

  10. More sensitive and quantitative proteomic measurements using very low flow rate porous silica monolithic LC columns with electrospray ionization-mass spectrometry

    SciTech Connect

    Luo, Quanzhou; Tang, Keqi; Yang, Feng; Elias, Ayesha; Shen, Yufeng; Moore, Ronald J.; Zhao, Rui; Hixson, Kim K.; Rossie, Sandra S.; Smith, Richard D.

    2006-05-01

    The sensitivity of proteomics measurements using liquid chromatography (LC) separations interfaced with electrospray ionization-mass spectrometry (ESI-MS) improves approximately inversely with liquid flow rate, making attractive the use of smaller inner diameter LC columns. We report the development and initial application of 10 µm i.d. silica-based monolithic LC columns providing more sensitive proteomics measurements. The implementation provides robust performance and suitability for automated proteome analyses due to integration with a micro solid phase extraction pre-column for ease of sample injection and clean-up prior to the reversed phased LC separation. Greater than 10-fold improvement in sensitivity was obtained compared to analyses using more conventional capillary LC, enabling e.g. the identification of >5000 different peptides by MS/MS from 100-ng of a Shewanella oneidensis tryptic digest using an ion trap MS. The low nL/min LC flow rates provide more uniform signal intensities for different peptides, and provided improved quantitative measurements compared to conventional separation systems without the use of internal standards or isotopic labeling. The improved sensitivity allowed LC-MS measurements of immunopurified protein phosphatase 5 that were in good agreement with quantitative western blot analyses.

  11. Rapid tea catechins and caffeine determination by HPLC using microwave-assisted extraction and silica monolithic column.

    PubMed

    Rahim, A A; Nofrizal, S; Saad, Bahruddin

    2014-03-15

    A rapid reversed-phase high performance liquid chromatographic method using a monolithic column for the determination of eight catechin monomers and caffeine was developed. Using a mobile phase of water:acetonitrile:methanol (83:6:11) at a flow rate of 1.4 mL min(-1), the catechins and caffeine were isocratically separated in about 7 min. The limits of detection and quantification were in the range of 0.11-0.29 and 0.33-0.87 mg L(-1), respectively. Satisfactory recoveries were obtained (94.2-105.2 ± 1.8%) for all samples when spiked at three concentrations (5, 40 and 70 mg L(-1)). In combination with microwave-assisted extraction (MAE), the method was applied to the determination of the catechins and caffeine in eleven tea samples (6 green, 3 black and 2 oolong teas). Relatively high levels of caffeine were found in black tea, but higher levels of the catechins, especially epigallocatechin gallate (EGCG) were found in green teas.

  12. Profiling of cis-diol-containing nucleosides and ribosylated metabolites by boronate-affinity organic-silica hybrid monolithic capillary liquid chromatography/mass spectrometry.

    PubMed

    Jiang, Han-Peng; Qi, Chu-Bo; Chu, Jie-Mei; Yuan, Bi-Feng; Feng, Yu-Qi

    2015-01-01

    RNA contains a large number of modified nucleosides. In the metabolic re-exchange of RNA, modified nucleosides cannot be recycled and are thus excreted from cells into biological fluids. Determination of endogenous modified nucleosides in biological fluids may serve as non-invasive cancers diagnostic methods. Here we prepared boronate-affinity organic-silica hybrid capillary monolithic column (BOHCMC) that exhibited excellent selectivity toward the cis-diol-containing compounds. We then used the prepared BOHCMC as the on-line solid-phase microextraction (SPME) column and developed an on-line SPME-LC-MS/MS method to comprehensively profile cis-diol-containing nucleosides and ribosylated metabolites in human urine. Forty-five cis-diol-containing nucleosides and ribosylated metabolites were successfully identified in human urine. And five ribose conjugates, for the first time, were identified existence in human urine in the current study. Furthermore, the relative quantification suggested 4 cis-diol-containing compounds (5'-deoxy-5'-methylthioadensine, N(4)-acetylcytidine, 1-ribosyl-N-propionylhistamine and N(2),N(2),7-trimethylguanosine) increased more than 1.5 folds in all the 3 types of examined cancers (lung cancer, colorectal cancer, and nasopharyngeal cancer) compared to healthy controls. The on-line SPME-LC-MS/MS method demonstrates a promising method for the comprehensive profiling of cis-diol-containing ribose conjugates in human urines, which provides an efficient strategy for the identification and discovery of biomarkers and may be used for the screening of cancers. PMID:25585609

  13. Profiling of cis-Diol-containing Nucleosides and Ribosylated Metabolites by Boronate-affinity Organic-silica Hybrid Monolithic Capillary Liquid Chromatography/Mass Spectrometry

    PubMed Central

    Jiang, Han-Peng; Qi, Chu-Bo; Chu, Jie-Mei; Yuan, Bi-Feng; Feng, Yu-Qi

    2015-01-01

    RNA contains a large number of modified nucleosides. In the metabolic re-exchange of RNA, modified nucleosides cannot be recycled and are thus excreted from cells into biological fluids. Determination of endogenous modified nucleosides in biological fluids may serve as non-invasive cancers diagnostic methods. Here we prepared boronate-affinity organic-silica hybrid capillary monolithic column (BOHCMC) that exhibited excellent selectivity toward the cis-diol-containing compounds. We then used the prepared BOHCMC as the on-line solid-phase microextraction (SPME) column and developed an on-line SPME-LC-MS/MS method to comprehensively profile cis-diol-containing nucleosides and ribosylated metabolites in human urine. Forty-five cis-diol-containing nucleosides and ribosylated metabolites were successfully identified in human urine. And five ribose conjugates, for the first time, were identified existence in human urine in the current study. Furthermore, the relative quantification suggested 4 cis-diol-containing compounds (5′-deoxy-5′-methylthioadensine, N4-acetylcytidine, 1-ribosyl-N-propionylhistamine and N2,N2,7-trimethylguanosine) increased more than 1.5 folds in all the 3 types of examined cancers (lung cancer, colorectal cancer, and nasopharyngeal cancer) compared to healthy controls. The on-line SPME-LC-MS/MS method demonstrates a promising method for the comprehensive profiling of cis-diol-containing ribose conjugates in human urines, which provides an efficient strategy for the identification and discovery of biomarkers and may be used for the screening of cancers. PMID:25585609

  14. Increased α1-3 fucosylation of α-1-acid glycoprotein (AGP) in pancreatic cancer.

    PubMed

    Balmaña, Meritxell; Giménez, Estela; Puerta, Angel; Llop, Esther; Figueras, Joan; Fort, Esther; Sanz-Nebot, Victoria; de Bolós, Carme; Rizzi, Andreas; Barrabés, Sílvia; de Frutos, Mercedes; Peracaula, Rosa

    2016-01-30

    Pancreatic cancer (PDAC) lacks reliable diagnostic biomarkers and the search for new biomarkers represents an important challenge. Previous results looking at a small cohort of patients showed an increase in α-1-acid glycoprotein (AGP) fucosylation in advanced PDAC using N-glycan sequencing. Here, we have analysed AGP glycoforms in a larger cohort using several analytical techniques including mass spectrometry (MS), capillary zone electrophoresis (CZE) and enzyme-linked lectin assays (ELLAs) for determining AGP glycoforms which could be PDAC associated. AGP from 31 serum samples, including healthy controls (HC), chronic pancreatitis (ChrP) and PDAC patients, was purified by immunoaffinity chromatography. Stable isotope labelling of AGP released N-glycans and their analysis by zwitterionic hydrophilic interaction capillary liquid chromatography electrospray MS (μZIC-HILIC-ESI-MS) showed an increase in AGP fucosylated glycoforms in PDAC compared to ChrP and HC. By CZE-UV analysis, relative concentrations of some of the AGP isoforms were found significantly different compared to those in PDAC and HC. Finally, ELLAs using Aleuria aurantia lectin displayed a significant increase in AGP fucosylation, before and after AGP neuraminidase treatment, in advanced PDAC compared to ChrP and HC, respectively. Altogether, these results indicate that α1-3 fucosylated glycoforms of AGP are increased in PDAC and could be potentially regarded as a PDAC biomarker. PMID:26563517

  15. Arabinogalactan protein 31 (AGP31), a putative network-forming protein in Arabidopsis thaliana cell walls?

    PubMed Central

    Hijazi, May; Roujol, David; Nguyen-Kim, Huan; del Rocio Cisneros Castillo, Liliana; Saland, Estelle; Jamet, Elisabeth; Albenne, Cécile

    2014-01-01

    Background and Aims Arabinogalactan protein 31 (AGP31) is a remarkable plant cell-wall protein displaying a multi-domain organization unique in Arabidopsis thaliana: it comprises a predicted signal peptide (SP), a short AGP domain of seven amino acids, a His-stretch, a Pro-rich domain and a PAC (PRP-AGP containing Cys) domain. AGP31 displays different O-glycosylation patterns with arabinogalactans on the AGP domain and Hyp-O-Gal/Ara-rich motifs on the Pro-rich domain. AGP31 has been identified as an abundant protein in cell walls of etiolated hypocotyls, but its function has not been investigated thus far. Literature data suggest that AGP31 may interact with cell-wall components. The purpose of the present study was to identify AGP31 partners to gain new insight into its function in cell walls. Methods Nitrocellulose membranes were prepared by spotting different polysaccharides, which were either obtained commercially or extracted from cell walls of Arabidopsis thaliana and Brachypodium distachyon. After validation of the arrays, in vitro interaction assays were carried out by probing the membranes with purified native AGP31 or recombinant PAC-V5-6xHis. In addition, dynamic light scattering (DLS) analyses were carried out on an AGP31 purified fraction. Key Results It was demonstrated that AGP31 interacts through its PAC domain with galactans that are branches of rhamnogalacturonan I. This is the first experimental evidence that a PAC domain, also found as an entire protein or a domain of AGP31 homologues, can bind carbohydrates. AGP31 was also found to bind methylesterified polygalacturonic acid, possibly through its His-stretch. Finally, AGP31 was able to interact with itself in vitro through its PAC domain. DLS data showed that AGP31 forms aggregates in solution, corroborating the hypothesis of an auto-assembly. Conclusions These results allow the proposal of a model of interactions of AGP31 with different cell-wall components, in which AGP31 participates in

  16. Transcriptional induction of the agp/ebp (c/ebp beta) gene by hepatocyte growth factor.

    PubMed

    Shen, B J; Chang, C J; Lee, H S; Tsai, W H; Miau, L H; Lee, S C

    1997-06-01

    Hepatocyte growth factor (HGF) is a pleiotropic factor with mitogenic, morphogenic, motogenic, cytotoxic, or growth inhibitory activity. Although the signaling of HGF is mediated through the cell membrane receptor c-Met, the molecular mechanism of downstream signal transduction remains obscure. In this report, we present evidence that shows HGF can stimulate the expression of AGP/EBP (C/EBP beta) and NF-kappaB, which are both key transcription factors responsible for the regulation of many genes under stress conditions or during the acute-phase response. Biochemical and functional analysis indicates that the HGF-responsive element is located in the region -376 to -352 (URE1) of the 5'-upstream regulatory sequence of agp/ebp. Activation of NF-kappaB by HGF was observed to precede the induction of agp/ebp. Further studies indicate that NF-kappaB can cooperate with AGP/EBP or other members of the C/EBP family to activate the agp/ebp gene in both URE1 and URE2-dependent manner. These results suggest that the induction of the agp/ebp gene by HGF is mediated at least in part by its activation of NF-kappaB. The activated NF-kappaB then interacts with AGP/EBP, resulting in the induction of agp/ebp.

  17. Monolithic Domes.

    ERIC Educational Resources Information Center

    Lanham, Carol

    2002-01-01

    Describes how the energy savings, low cost, and near-absolute protection from tornadoes provided by monolithic domes is starting to appeal to school districts for athletic and other facilities, including the Italy (Texas) Independent School District. Provides an overview of monolithic dome construction. (EV)

  18. AGP: a multimethods web server for alignment-free genome phylogeny.

    PubMed

    Cheng, Jinkui; Cao, Fuliang; Liu, Zhihua

    2013-05-01

    Phylogenetic analysis based on alignment method meets huge challenges when dealing with whole-genome sequences, for example, recombination, shuffling, and rearrangement of sequences. Thus, various alignment-free methods for phylogeny construction have been proposed. However, most of these methods have not been implemented as tools or web servers. Researchers cannot use these methods easily with their data sets. To facilitate the usage of various alignment-free methods, we implemented most of the popular alignment-free methods and constructed a user-friendly web server for alignment-free genome phylogeny (AGP). AGP integrated the phylogenetic tree construction, visualization, and comparison functions together. Both AGP and all source code of the methods are available at http://www.herbbol.org:8000/agp (last accessed February 26, 2013). AGP will facilitate research in the field of whole-genome phylogeny and comparison.

  19. AtAGP18 is localized at the plasma membrane and functions in plant growth and development.

    PubMed

    Zhang, Yizhu; Yang, Jie; Showalter, Allan M

    2011-04-01

    Arabinogalactan-proteins (AGPs) are a family of highly glycosylated hydroxyproline-rich glycoproteins (HRGPs). AtAGP17, 18 and 19 comprise the lysine-rich classical AGP subfamily in Arabidopsis. Overexpression of GFP-AtAGP17/18/19 fusion proteins in Arabidopsis revealed localization of the fusion proteins on the plant cell surface of different organs. Subcellular localization of the fusion proteins at the plasma membrane was further determined by plasmolysis of leaf trichome cells. To elucidate AtAGP17/18/19 function(s), these AGPs were expressed without the green fluorescent protein (GFP) tag under the control of 35S cauliflower mosaic virus promoter. In contrast to AtAGP17/AtAGP19 overexpressors which showed phenotypes identical to wild-type plants, AtAGP18 overexpressors displayed several phenotypes distinct from wild-type plants. Specifically, these overexpressors had smaller rosettes and shorter stems and roots, produced more branches and had less viable seeds. Moreover, these AtAGP18 overexpressors exhibited similar phenotypes to tomato LeAGP-1 overexpressors, suggesting these two AGP genes may have similar function(s) in Arabidopsis and tomato. PMID:21165646

  20. Discovery of Inhibitors for the Ether Lipid-Generating Enzyme AGPS as Anti-Cancer Agents

    PubMed Central

    Piano, Valentina; Benjamin, Daniel I; Valente, Sergio; Nenci, Simone; Mai, Antonello; Aliverti, Alessandro; Nomura, Daniel K; Mattevi, Andrea

    2015-01-01

    Dysregulated ether lipid metabolism is an important hallmark of cancer cells. Previous studies have reported that lowering ether lipid levels by genetic ablation of the ether lipid-generating enzyme alkyl-glycerone phosphate synthase (AGPS) lowers key structural and oncogenic ether lipid levels and alters fatty acid, glycerophospholipid, and eicosanoid metabolism to impair cancer pathogenicity, indicating that AGPS may be a potential therapeutic target for cancer. In this study, we have performed a small-molecule screen to identify candidate AGPS inhibitors. We have identified several lead AGPS inhibitors and have structurally characterized their interactions with the enzyme and show that these inhibitors bind to distinct portions of the active site. We further show that the lead AGPS inhibitor 1a selectively lowers ether lipid levels in several types of human cancer cells and impairs their cellular survival and migration. We provide here the first report of in situ-effective pharmacological tools for inhibiting AGPS, which may provide chemical scaffolds for future AGPS inhibitor development for cancer therapy. PMID:26322624

  1. Discovery of Inhibitors for the Ether Lipid-Generating Enzyme AGPS as Anti-Cancer Agents.

    PubMed

    Piano, Valentina; Benjamin, Daniel I; Valente, Sergio; Nenci, Simone; Marrocco, Biagina; Mai, Antonello; Aliverti, Alessandro; Nomura, Daniel K; Mattevi, Andrea

    2015-11-20

    Dysregulated ether lipid metabolism is an important hallmark of cancer cells. Previous studies have reported that lowering ether lipid levels by genetic ablation of the ether lipid-generating enzyme alkyl-glycerone phosphate synthase (AGPS) lowers key structural and oncogenic ether lipid levels and alters fatty acid, glycerophospholipid, and eicosanoid metabolism to impair cancer pathogenicity, indicating that AGPS may be a potential therapeutic target for cancer. In this study, we have performed a small-molecule screen to identify candidate AGPS inhibitors. We have identified several lead AGPS inhibitors and have structurally characterized their interactions with the enzyme and show that these inhibitors bind to distinct portions of the active site. We further show that the lead AGPS inhibitor 1a selectively lowers ether lipid levels in several types of human cancer cells and impairs their cellular survival and migration. We provide here the first report of in situ-active pharmacological tools for inhibiting AGPS, which may provide chemical scaffolds for future AGPS inhibitor development for cancer therapy.

  2. Monolithic spectrometer

    DOEpatents

    Rajic, S.; Egert, C.M.; Kahl, W.K.; Snyder, W.B. Jr.; Evans, B.M. III; Marlar, T.A.; Cunningham, J.P.

    1998-05-19

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays. 6 figs.

  3. Monolithic spectrometer

    DOEpatents

    Rajic, Slobodan; Egert, Charles M.; Kahl, William K.; Snyder, Jr., William B.; Evans, III, Boyd M.; Marlar, Troy A.; Cunningham, Joseph P.

    1998-01-01

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays.

  4. The glycosylation of AGP and its associations with the binding to methadone.

    PubMed

    Behan, Jennifer L; Cruickshank, Yvonne E; Matthews-Smith, Gerri; Bruce, Malcolm; Smith, Kevin D

    2013-01-01

    Methadone remains the most common form of pharmacological therapy for opioid dependence; however, there is a lack of explanation for the reports of its relatively low success rate in achieving complete abstinence. One hypothesis is that in vivo binding of methadone to the plasma glycoprotein alpha-1-acid glycoprotein (AGP), to a degree dependent on the molecular structure, may render the drug inactive. This study sought to determine whether alterations present in the glycosylation pattern of AGP in patients undergoing various stages of methadone therapy (titration < two weeks, harm reduction < one year, long-term > one and a half years) could affect the affinity of the glycoprotein to bind methadone. The composition of AGP glycosylation was determined using high pH anion exchange chromatography (HPAEC) and intrinsic fluorescence analysed to determine the extent of binding to methadone. The monosaccharides galactose and N-acetyl-glucosamine were elevated in all methadone treatment groups indicating alterations in AGP glycosylation. AGP from all patients receiving methadone therapy exhibited a greater degree of binding than the normal population. This suggests that analysing the glycosylation of AGP in patients receiving methadone may aid in determining whether the therapy is likely to be effective.

  5. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    DOEpatents

    Wang, Daojing; Yang, Peidong; Kim, Woong; Fan, Rong

    2011-09-20

    Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

  6. Counterflow isotachophoresis in a monolithic column.

    PubMed

    Liu, Bingwen; Cong, Yongzheng; Ivory, Cornelius F

    2014-09-01

    This study describes stationary counterflow isotachophoresis (ITP) in a poly(acrylamide-co-N,N'-methylenebisacrylamide) monolithic column as a means for improving ITP processing capacity and reducing dispersion. The flow profile in the monolith was predicted using COMSOL's Brinkman Equation application mode, which revealed that the flow profile was mainly determined by monolith permeability. As monolith permeability decreases, the flow profile changes from a parabolic shape to a plug shape. An experimental monolithic column was prepared in a fused-silica capillary using an ultraviolet-initiated polymerization method. A monolithic column made from 8% (wt.) monomer was chosen for the stationary counterflow ITP experiments. Counterflow ITP in the monolithic column showed undistorted analyte zones with significantly reduced dispersion compared to the severe dispersion observed in an open capillary. Particularly, for r-phycoerythrin focused by counterflow ITP, its zone width in the monolithic column was only one-third that observed in an open capillary. These experiments demonstrate that stationary counterflow ITP in monoliths can be a robust and practical electrofocusing method.

  7. Synthesis and applications of monolithic HPLC columns

    NASA Astrophysics Data System (ADS)

    Liang, Chengdu

    Silica and carbon monolithic columns were synthesized and modified for liquid chromatography applications. Column configurations and cladding techniques were investigated in detail. Three novel approaches have been developed for the synthesis of bimodal porous rods. Out of these three methods, gel-casting was adopted for the synthesis of silica monoliths with ordered mesopores and uniform macropores; the use of colloidal templates and dual phase separation has been successfully implemented for the synthesis of carbon monoliths with well-controlled meso- and macro- porosities. The formation of mesopores in carbon materials has been further studied in the microphase separation of block copolymers. Electrochemical modification of carbon monoliths was discovered to be an efficient method for converting covalently bonded functionalities to carbon monoliths. N,N'-diethylaminobenzene has been attached to carbon surface for the separation of proteins and protein digests. The performances of carbon-based monolithic columns were studied intensely through frontal analysis and Van Deemter plot. Temperature and pressure effects were also investigated in carbon-based columns. The density of bonding on the modified carbon monoliths was characterized by thermogravimetric analysis.

  8. CsAGP1, a Gibberellin-Responsive Gene from Cucumber Hypocotyls, Encodes a Classical Arabinogalactan Protein and Is Involved in Stem Elongation

    PubMed Central

    Park, Me Hea; Suzuki, Yoshihito; Chono, Makiko; Knox, J. Paul; Yamaguchi, Isomaro

    2003-01-01

    Fluorescence differential display was used to isolate the gibberellin (GA)-responsive gene, CsAGP1, from cucumber (Cucumis sativus) hypocotyls. A sequence analysis of CsAGP1 indicated that the gene putatively encodes a “classical” arabinogalactan protein (AGP) in cucumber. Transgenic tobacco (Nicotiana tabacum) plants overexpressing CsAGP1 under the control of the cauliflower mosaic virus 35S promoter produced a Y(βGlc)3-reactive proteoglycan in addition to AGPs present in wild-type tobacco plants. Immuno-dot blotting of the product, using anti-AGP antibodies, showed that the CsAGP1 protein had the AGP epitopes common to AGP families. The transcription level of CsAGP1 in cucumber hypocotyls increased in response not only to GA but also to indole-3-acetic acid. Although CsAGP1 is expressed in most vegetative tissues of cucumber, including the shoot apices and roots, the GA treatment resulted in an increase in the mRNA level of CsAGP1 only in the upper part of the hypocotyls. Y(βGlc)3, which selectively binds AGPs, inhibited the hormone-promoted elongation of cucumber seedling hypocotyls. Transgenic plants ectopically expressing CsAGP1 showed a taller stature and earlier flowering than the wild-type plants. These observations suggest that CsAGP1 is involved in stem elongation. PMID:12644694

  9. CsAGP1, a gibberellin-responsive gene from cucumber hypocotyls, encodes a classical arabinogalactan protein and is involved in stem elongation.

    PubMed

    Park, Me Hea; Suzuki, Yoshihito; Chono, Makiko; Knox, J Paul; Yamaguchi, Isomaro

    2003-03-01

    Fluorescence differential display was used to isolate the gibberellin (GA)-responsive gene, CsAGP1, from cucumber (Cucumis sativus) hypocotyls. A sequence analysis of CsAGP1 indicated that the gene putatively encodes a "classical" arabinogalactan protein (AGP) in cucumber. Transgenic tobacco (Nicotiana tabacum) plants overexpressing CsAGP1 under the control of the cauliflower mosaic virus 35S promoter produced a Y(betaGlc)(3)-reactive proteoglycan in addition to AGPs present in wild-type tobacco plants. Immuno-dot blotting of the product, using anti-AGP antibodies, showed that the CsAGP1 protein had the AGP epitopes common to AGP families. The transcription level of CsAGP1 in cucumber hypocotyls increased in response not only to GA but also to indole-3-acetic acid. Although CsAGP1 is expressed in most vegetative tissues of cucumber, including the shoot apices and roots, the GA treatment resulted in an increase in the mRNA level of CsAGP1 only in the upper part of the hypocotyls. Y(betaGlc)(3), which selectively binds AGPs, inhibited the hormone-promoted elongation of cucumber seedling hypocotyls. Transgenic plants ectopically expressing CsAGP1 showed a taller stature and earlier flowering than the wild-type plants. These observations suggest that CsAGP1 is involved in stem elongation.

  10. Macroporous silver monoliths using a simple surfactant

    NASA Astrophysics Data System (ADS)

    Khan, Farid; Eswaramoorthy, Muthusamy; Rao, C. N. R.

    2007-01-01

    An elegant method to synthesize porous silver monoliths using a simple surfactant cum reductant, Triton X-114, as the sacrificial template is described. The gel forming property of the surfactant with silver nitrate is utilized to make the porous framework. The monoliths obtained with a mixture of Triton X-114 and dextran have also been examined. A significant improvement in the pore structure was observed when Triton X-114 was used along with Ludox silica sol, followed by calcination and HF treatment. The presence of interparticle pores in the 20-25 nm range on the macroporous silver framework suggests the role of silica spheres in the nanopore formation.

  11. Transcriptional induction of the alpha-1 acid glycoprotein (AGP) gene by synergistic interaction of two alternative activator forms of AGP/enhancer-binding protein (C/EBP beta) and NF-kappaB or Nopp140.

    PubMed Central

    Lee, Y M; Miau, L H; Chang, C J; Lee, S C

    1996-01-01

    Alpha-1 acid glycoprotein/enhancer-binding protein (AGP/EBP) (C/EBPbeta), a member of the C/EBP family, is one of the key transcription factors responsible for the induction of a wide array of genes, some of which are expressed during the acute-phase response. Both activator and repressor were shown to be encoded by the intronless agp/ebp or its rat and human homologs, which contain a common bZIP domain at their C-terminal regions. Expression of the AGP gene (agp) is regulated by AGP/EBP in liver during the acute-phase response. However, the molecular mechanism for this regulation is poorly understood. The experiments reported here demonstrate that two activator forms of AGP/EBP, one of which has an additional 21 amino acids at its N-terminal region, are expressed in liver as well as in a number of cell lines. We have also demonstrated that NF-kappaB and a phosphoprotein of 140 kDa, Nopp140, interact with different AGP/EBP activators synergistically, which results in induction of the agp gene in an AGP/EBP-binding-motif-dependent manner. Furthermore, extracellular stimuli that are known to be NF-kappaB inducers can selectively activate the agp gene by cooperating with one of the two activator forms of AGP/EBP. The physiological significance of differential regulation for the function of two activator forms of AGP/EBP through selective interaction with different transcription factors is discussed. PMID:8754826

  12. Transcriptional induction of the alpha-1 acid glycoprotein (AGP) gene by synergistic interaction of two alternative activator forms of AGP/enhancer-binding protein (C/EBP beta) and NF-kappaB or Nopp140.

    PubMed

    Lee, Y M; Miau, L H; Chang, C J; Lee, S C

    1996-08-01

    Alpha-1 acid glycoprotein/enhancer-binding protein (AGP/EBP) (C/EBPbeta), a member of the C/EBP family, is one of the key transcription factors responsible for the induction of a wide array of genes, some of which are expressed during the acute-phase response. Both activator and repressor were shown to be encoded by the intronless agp/ebp or its rat and human homologs, which contain a common bZIP domain at their C-terminal regions. Expression of the AGP gene (agp) is regulated by AGP/EBP in liver during the acute-phase response. However, the molecular mechanism for this regulation is poorly understood. The experiments reported here demonstrate that two activator forms of AGP/EBP, one of which has an additional 21 amino acids at its N-terminal region, are expressed in liver as well as in a number of cell lines. We have also demonstrated that NF-kappaB and a phosphoprotein of 140 kDa, Nopp140, interact with different AGP/EBP activators synergistically, which results in induction of the agp gene in an AGP/EBP-binding-motif-dependent manner. Furthermore, extracellular stimuli that are known to be NF-kappaB inducers can selectively activate the agp gene by cooperating with one of the two activator forms of AGP/EBP. The physiological significance of differential regulation for the function of two activator forms of AGP/EBP through selective interaction with different transcription factors is discussed.

  13. Highly stable, monolithic, single-mode mid-infrared supercontinuum source based on low-loss fusion spliced silica and fluoride fibers.

    PubMed

    Yin, Ke; Zhang, Bin; Yao, Jinmei; Yang, Linyong; Chen, Shengping; Hou, Jing

    2016-03-01

    A 0.8 to 4.5 μm highly stable all-fiber spliced mid-infrared supercontinuum (SC) source was presented. The joint between the single-mode (SM) pump silica fiber and the ZBLAN fiber (ZrF4 - BaF2 - LaF3 - AlF3 - NaF, a type of fluoride fiber) was fusion spliced, which greatly improved the SC's stability. The low-loss splicing was guaranteed by the similar mode field areas of the fundamental mode LP(01) of the silica and ZBLAN fibers. At the splicing joint the ZBLAN fiber enveloped the silica fiber, thus increasing the robustness of the splice. A low splicing loss of less than 0.1 dB was calculated, which ensured that the whole SC source was very reliable. The SC had a maximal average power of 550.8 mW with a 1.5 dB spectral bandwidth ranging from 2642 to 4065 nm. In particular, the SC power for λ>3.8  μm was measured to be 116.1 mW with a power ratio of ∼21.1% of the total SC power. Perfect Gaussian beam profiles of the SC source demonstrated its SM operation. Over 12 h of continuous operation of this SC source showed its outstanding power stability with a root mean square variation of 0.59%, which also demonstrated the high quality of the fusion spliced joint. PMID:26974087

  14. Selective microemulsion liquid chromatography analysis of dopamine receptor antagonist LE300 and its N-methyl metabolite in mouse sera by using a monolithic silica column.

    PubMed

    Al-Majed, Abdulrhman A; Hefnawy, Mohamed M; Mohammed, Mostafa S; Attia, Sabry M; Lehmann, Jochen

    2015-05-01

    A highly selective, sensitive, and rapid microemulsion liquid chromatography (MELC) method was developed and validated for the simultaneous determination of a novel type of dopamine receptor antagonist LE300 and its N-methyl metabolite in mouse sera. LE300, its N-methyl metabolite, and pindolol (an internal standard) were detected using excitation and emission wavelengths of 275 and 340 nm, respectively. HPLC analysis by using a monolithic column was performed by directly injecting the sample after appropriate dilution with the microemulsion mobile phase. The chromatographic behaviour of these compounds was studied to demonstrate their chromatographic efficiency, retention, and peak symmetry. The MELC method was validated for its specificity, linearity, accuracy, precision, robustness and stability. An experimental design was used during validation to evaluate method robustness. The calibration curves in serum showed excellent linearity (r=0.997) over concentrations ranging from 10 to 400 ngmL(-1) for LE300 and 15 to 500 ngmL(-1) for its N-methyl metabolite. The mean relative standard deviation (RSD) of the results of inter- and intra-day precision and accuracy of LE300 and its N-methyl metabolite were ≤5%. The overall recoveries of LE300 and its N-methyl metabolite from mouse sera were in the range 97.9-101.5% with %RSD ranging from 0.98% to 3.63%, which were in line with ICH guidelines. The assay was successfully applied in a pharmacokinetic study.

  15. Monolithic ceramics

    NASA Technical Reports Server (NTRS)

    Herbell, Thomas P.; Sanders, William A.

    1992-01-01

    A development history and current development status evaluation are presented for SiC and Si3N4 monolithic ceramics. In the absence of widely sought improvements in these materials' toughness, and associated reliability in structural applications, uses will remain restricted to components in noncritical, nonman-rated aerospace applications such as cruise missile and drone gas turbine engine components. In such high temperature engine-section components, projected costs lie below those associated with superalloy-based short-life/expendable engines. Advancements are required in processing technology for the sake of fewer and smaller microstructural flaws.

  16. Identification of alpha-1 acid glycoprotein (AGP) as a potential marker of impaired growth in the newborn piglet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two studies were conducted to investigate the relationship between the circulating levels of the acute phase proteins haptoglobin (HP) and alpha 1 acid glycoprotein (AGP) and growth potential in neonatal pigs. In runts, the circulating level of AGP, but not HP in serum of newborn piglets was higher...

  17. Increased thermal conductivity monolithic zeolite structures

    DOEpatents

    Klett, James; Klett, Lynn; Kaufman, Jonathan

    2008-11-25

    A monolith comprises a zeolite, a thermally conductive carbon, and a binder. The zeolite is included in the form of beads, pellets, powders and mixtures thereof. The thermally conductive carbon can be carbon nano-fibers, diamond or graphite which provide thermal conductivities in excess of about 100 W/mK to more than 1,000 W/mK. A method of preparing a zeolite monolith includes the steps of mixing a zeolite dispersion in an aqueous colloidal silica binder with a dispersion of carbon nano-fibers in water followed by dehydration and curing of the binder is given.

  18. Redox regulation of glycogen biosynthesis in the cyanobacterium Synechocystis sp. PCC 6803: analysis of the AGP and glycogen synthases.

    PubMed

    Díaz-Troya, Sandra; López-Maury, Luis; Sánchez-Riego, Ana María; Roldán, Miguel; Florencio, Francisco J

    2014-01-01

    Glycogen constitutes the major carbon storage source in cyanobacteria, as starch in algae and higher plants. Glycogen and starch synthesis is linked to active photosynthesis and both of them are degraded to glucose in the dark to maintain cell metabolism. Control of glycogen biosynthesis in cyanobacteria could be mediated by the regulation of the enzymes involved in this process, ADP-glucose pyrophosphorylase (AGP) and glycogen synthase, which were identified as putative thioredoxin targets. We have analyzed whether both enzymes were subjected to redox modification using purified recombinant enzymes or cell extracts in the model cyanobacterium Synechocystis sp. PCC 6803. Our results indicate that both AGP and glycogen synthases are sensitive to copper oxidation. However, only AGP exhibits a decrease in its enzymatic activity, which is recovered after reduction by DTT or reduced thioredoxin (TrxA), suggesting a redox control of AGP. In order to elucidate the role in redox control of the cysteine residues present on the AGP sequence (C45, C185, C320, and C337), they were replaced with serine. All AGP mutant proteins remained active when expressed in Synechocystis, although they showed different electrophoretic mobility profiles after copper oxidation, reflecting a complex pattern of cysteines interaction.

  19. Process for Preparing Epoxy-Reinforced Silica Aerogels

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B (Inventor)

    2016-01-01

    One-pot reaction process for preparing epoxy-reinforced monolithic silica aerogels comprising the reaction of at least one silicon compound selected from the group consisting of alkoxysilanes, orthosilicates and combination thereof in any ratio with effective amounts of an epoxy monomer and an aminoalkoxy silane to obtain an epoxy monomer-silica sol in solution, subsequently preparing an epoxy-monomer silica gel from said silica sol solution followed by initiating polymerization of the epoxy monomer to obtain the epoxy-reinforced monolithic silica aerogel.

  20. Method for making monolithic metal oxide aerogels

    DOEpatents

    Droege, M.W.; Coronado, P.R.; Hair, L.M.

    1995-03-07

    Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The present invention is especially advantageous for making metal oxides other than silica that are prone to forming opaque, cracked aerogels. 6 figs.

  1. Method for making monolithic metal oxide aerogels

    DOEpatents

    Droege, Michael W.; Coronado, Paul R.; Hair, Lucy M.

    1995-01-01

    Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The present invention is especially advantageous for making metal oxides other than silica that are prone to forming opaque, cracked aerogels.

  2. Process for preparing polymer reinforced silica aerogels

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B. (Inventor); Capadona, Lynn A. (Inventor)

    2011-01-01

    Process for preparing polymer-reinforced silica aerogels which comprises a one-pot reaction of at least one alkoxy silane in the presence of effective amounts of a polymer precursor to obtain a silica reaction product, the reaction product is gelled and subsequently subjected to conditions that promotes polymerization of the precursor and then supercritically dried to obtain the polymer-reinforced monolithic silica aerogels.

  3. Ether lipid generating enzyme AGPS alters the balance of structural and signaling lipids to fuel cancer pathogenicity.

    PubMed

    Benjamin, Daniel I; Cozzo, Alyssa; Ji, Xiaodan; Roberts, Lindsay S; Louie, Sharon M; Mulvihill, Melinda M; Luo, Kunxin; Nomura, Daniel K

    2013-09-10

    Aberrant lipid metabolism is an established hallmark of cancer cells. In particular, ether lipid levels have been shown to be elevated in tumors, but their specific function in cancer remains elusive. We show here that the metabolic enzyme alkylglyceronephosphate synthase (AGPS), a critical step in the synthesis of ether lipids, is up-regulated across multiple types of aggressive human cancer cells and primary tumors. We demonstrate that ablation of AGPS in cancer cells results in reduced cell survival, cancer aggressiveness, and tumor growth through altering the balance of ether lipid, fatty acid, eicosanoid, and fatty acid-derived glycerophospholipid metabolism, resulting in an overall reduction in the levels of several oncogenic signaling lipids. Taken together, our results reveal that AGPS, in addition to maintaining ether lipids, also controls cellular utilization of fatty acids, favoring the generation of signaling lipids necessary for promoting the aggressive features of cancer. PMID:23980144

  4. Monolithic exploding foil initiator

    DOEpatents

    Welle, Eric J; Vianco, Paul T; Headley, Paul S; Jarrell, Jason A; Garrity, J. Emmett; Shelton, Keegan P; Marley, Stephen K

    2012-10-23

    A monolithic exploding foil initiator (EFI) or slapper detonator and the method for making the monolithic EFI wherein the exploding bridge and the dielectric from which the flyer will be generated are integrated directly onto the header. In some embodiments, the barrel is directly integrated directly onto the header.

  5. New Monolithic Dome Schools.

    ERIC Educational Resources Information Center

    Parker, Freda

    2000-01-01

    Discusses how the Grand Meadow (Minnesota) school district got more than twice the grant money asked for from the state's legislature as well as voter approval for five new $8 million monolithic domes for their K-12 facility. Three additional school district successes in developing monolithic domes for their schools are examined. (GR)

  6. Weak anion exchange chromatographic profiling of glycoprotein isoforms on a polymer monolithic capillary.

    PubMed

    Liu, Jing; Ren, Lianbing; Liu, Yunchun; Li, Hengye; Liu, Zhen

    2012-03-01

    High resolution separation of intact glycoproteins, which is essential for many aspects such as finger-print profiling, represents a great challenge because one glycoprotein can exhibit many isoforms with close physicochemical properties. Monolithic columns are important separation media for the separation of intact proteins due to its significant advantages such as easy preparation, high column efficiency and high permeability. However, there are few reports on high resolution profiling of intact glycoproteins. Herein, we presented a polymeric weak anion exchange (WAX) monolithic capillary for high resolution separation of glycoprotein isoforms. A base monolith was first prepared through ring-opening polymerization between tris(2,3-epoxypropyl)isocyanurate and tri(2-aminoethyl), and then modified through reacting with ammonia aqueous solution to convert the unreacted epoxide moieties into primary amino groups. The prepared monolithic capillary was characterized in terms of morphology, pore size, hydrophilicity and reproducibility. The obtained WAX monolithic capillary exhibited desired through-pores and mesopore size, stable skeleton and hydrophilic nature. The performance of the capillary was evaluated using several typical glycoproteins such as α(1)-acid glycoprotein (AGP) as mode analytes. Effects of the experimental parameters on the glycoform resolution were investigated. Under the optimized separation conditions, the tested glycoproteins were all resolved into distinct glycoforms. A comparative investigation with capillary zone electrophoresis (CZE) revealed that this WAX column provided better selectivity as more isoforms were observed, although the resolution of some glycoprotein isoforms decreased.

  7. Focussed ion beam serial sectioning and imaging of monolithic materials for 3D reconstruction and morphological parameter evaluation.

    PubMed

    Vázquez, Mercedes; Moore, David; He, Xiaoyun; Ben Azouz, Aymen; Nesterenko, Ekaterina; Nesterenko, Pavel; Paull, Brett; Brabazon, Dermot

    2014-01-01

    A new characterisation method, based on the utilisation of focussed ion beam-scanning electron microscopy (FIB-SEM), has been employed for the evaluation of morphological parameters in porous monolithic materials. Sample FIB serial sectioning, SEM imaging and image processing techniques were used to extract the pore boundaries and reconstruct the 3D porous structure of carbon and silica-based monoliths. Since silica is a non-conducting material, a commercial silica monolith modified with activated carbon was employed instead to minimise the charge build-up during FIB sectioning. This work therefore presents a novel methodology that can be successfully employed for 3D reconstruction of porous monolithic materials which are or can be made conductive through surface or bulk modification. Furthermore, the 3D reconstructions were used for calculation of the monolith macroporosity, which was in good agreement with the porosity values obtained by mercury intrusion porosimetry (MIP).

  8. Effective and reusable monolith capillary trap of nitrosamine extraction by superheated water from frankfurter sausage.

    PubMed

    Chienthavorn, Orapin; Ramnut, Narumol; Subprasert, Panee; Sasook, Anupop; Insuan, Wimonrut

    2014-02-12

    A novel, simple, rapid, and inexpensive method of extraction and cleanup of nitrosamines from frankfurter sausage was achieved with a capillary filled with monolith of either polystyrene-co-divinylbenzene (PS-DVB), Polydivinylbenzene (P-DVB), or silica that had been fabricated. The study of capability in trapping nonpolar matrix and monolith capillaries with varied lengths revealed that a silica monolith gave the best result for nitrosamine determination. With an online coupling between superheated water extraction (SWE) and silica monolith capillary connected to a 5% phenyl-methylpolysiloxane column, factors affecting the extraction and determination, namely, sensitivity with and without the monolith, reusability, injection-injection repeatability, capillary-capillary precision, and chromatographic separation, were investigated. This confirmed the feasibility of the method. The optimal length of silica monolith capillary was 30 mm, offering reuse more than 20 times. Separation and quantification of selected volatile nitrosamines were carried out using gas chromatography (GC) coupled with either a flame ionization detector (FID) or mass spectrometer (MS). The overall extraction and determination method determined by GC-MS allowed for a recovery of 75-88% with a <5% relative standard deviation (RSD) and detection limit of 2-5 ng of injected nitrosamine.

  9. [Preparation of organic-inorganic hybrid boronate affinity monolith via thiol-ene click reaction for specific capture of glycoproteins].

    PubMed

    Yang, Fan; Mao, Jie; He, Xiwen; Chen, Langxing; Zhang, Yukui

    2013-06-01

    A novel strategy for the preparation of the organic-inorganic hybrid boronate affinity monolith was developed via the "thiol-ene" click reaction. A thiol group-modified silica monolith was first synthesized via the sol-gel process by the in situ co-condensation with tetramethoxysilane (TMOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) as precursors. Then 3-acrylamidophenylboronic acid (AAPBA) was covalently immobilized on the hybrid monolith via the "thiol-ene" click reaction to form AAPBA-silica hybrid affinity monolith. The reaction conditions for the preparation of AAPBA-silica hybrid affinity monolith were optimized, including the ratio of TMOS to MPTMS, the contents of poly(ethylene glycol) (PEG) and methanol. The morphology and mechanical stability of the boronate affinity monolith were characterized and evaluated by scanning electron microscopy and Fourier-transform infrared spectroscopy. The obtained boronate affinity hybrid monolith exhibited excellent specificity toward the nucleosides containing cis-diols under neutral conditions. It was further applied to the specific capture of the glycoproteins ovalbumin and horseradish peroxidase. The method is novel and reliable, which has a great potential for the preparation of different kinds of the boronate affinity monoliths.

  10. Monolithic microwave integrated circuits

    NASA Astrophysics Data System (ADS)

    Pucel, R. A.

    Monolithic microwave integrated circuits (MMICs), a new microwave technology which is expected to exert a profound influence on microwave circuit designs for future military systems as well as for the commercial and consumer markets, is discussed. The book contains an historical discussion followed by a comprehensive review presenting the current status in the field. The general topics of the volume are: design considerations, materials and processing considerations, monolithic circuit applications, and CAD, measurement, and packaging techniques. All phases of MMIC technology are covered, from design to testing.

  11. Monolithic microextraction tips by emulsion photopolymerization.

    PubMed

    Liang, Shih-Shin; Chen, Shu-Hui

    2009-03-20

    Monoliths formed by photopolymerization are excellent means for fabricating functional elements in miniaturized microdevices such as microextraction tips which are becoming important for sample preparation. Various silica-based and polymer-based materials have been used to fabricate monoliths with through pores of several nm to 4 microm. However, the back pressure created by such methods is still considered to be high for microtips that use suction forces to deliver the liquid. In this study, we demonstrated that emulsion techniques such as oil-in-water can be used to form monoliths with large through pores (>20 microm), and with rigid structures on small (10 microL) and large (200 microL) pipette tips by photopolymerization. We further showed that, with minor modifications, various functionalized particles (5-20 microm) can be added to form stable emulsions and successfully encapsulated into the monoliths for qualitative and quantitative solid-phase microextractions for a diverse application. Due to high permeability and large surface area, quick equilibration can be achieved by pipetting to yield high recovery rates. Using tryptic digests of ovalbumin as the standard, we obtained a recovery yield of 90-109% (RSD: 10-16%) with a loading capacity of 3 mug for desalting tips immobilized with C18 beads. Using tryptic digests of beta-casein and alpha-casein as standards, we showed that phosphopeptides were substantially enriched by tips immobilized with immobilized metal affinity chromatography or TiO(2) materials. Using estrogenic compounds as standards, we obtained a recovery yield of 95-108% (RSD: 10-12%) and linear calibration curves ranging from 5 to 100 ng (R(2)>0.99) for Waters Oasis HLB tips immobilized with hydrophilic beads. PMID:19203757

  12. Photopolymerized sol-gel monoliths for separations of glycosylated proteins and peptides in microfluidic chips.

    PubMed

    Levy, Miriam H; Plawsky, Joel; Cramer, Steven M

    2013-07-01

    Photopolymerized silica sol-gel monoliths, functionalized with boronic acid ligands, have been developed for protein and peptide separations in polydimethylsiloxane microfluidic devices. Pore size characterization of the monoliths was carried out with SEM, image analysis, and differential scanning calorimetry to evaluate both the micron-sized macropores and the nanometer-sized mesopores. Monoliths were functionalized with boronic acid using three different immobilization techniques. Batch experiments were conducted to determine the capacity of the monoliths and selectivity toward cis-diol-containing compounds. Conalbumin was used as a model glycoprotein, and a tryptic digest of the glycoprotein horseradish peroxidase was used as a peptide mixture to demonstrate proof-of-concept extraction of glycoproteins and glycopeptides by the monoliths formulated in polydimethylsiloxane microfluidic chips. For proteins, fluorescence detection was used, whereas the peptide separations employed off-line analysis using MALDI-MS. PMID:23703808

  13. The SAGA histone acetyltransferase complex regulates leucine uptake through the Agp3 permease in fission yeast.

    PubMed

    Takahashi, Hidekazu; Sun, Xiaoying; Hamamoto, Makiko; Yashiroda, Yoko; Yoshida, Minoru

    2012-11-01

    Metabolic responses of unicellular organisms are mostly acute, transient, and cell-autonomous. Regulation of nutrient uptake in yeast is one such rapid response. High quality nitrogen sources such as NH(4)(+) inhibit uptake of poor nitrogen sources, such as amino acids. Both transcriptional and posttranscriptional mechanisms operate in nutrient uptake regulation; however, many components of this system remain uncharacterized in the fission yeast, Schizosaccharomyces pombe. Here, we demonstrate that the Spt-Ada-Gcn acetyltransferase (SAGA) complex modulates leucine uptake. Initially, we noticed that a branched-chain amino acid auxotroph exhibits a peculiar adaptive growth phenotype on solid minimal media containing certain nitrogen sources. In fact, the growth of many auxotrophic strains is inhibited by excess NH(4)Cl, possibly through nitrogen-mediated uptake inhibition of the corresponding nutrients. Surprisingly, DNA microarray analysis revealed that the transcriptional reprogramming during the adaptation of the branched-chain amino acid auxotroph was highly correlated with reprogramming observed in deletions of the SAGA histone acetyltransferase module genes. Deletion of gcn5(+) increased leucine uptake in the prototrophic background and rendered the leucine auxotroph resistant to NH(4)Cl. Deletion of tra1(+) caused the opposite phenotypes. The increase in leucine uptake in the gcn5Δ mutant was dependent on an amino acid permease gene, SPCC965.11c(+). The closest budding yeast homolog of this permease is a relatively nonspecific amino acid permease AGP3, which functions in poor nutrient conditions. Our analysis identified the regulation of nutrient uptake as a physiological function for the SAGA complex, providing a potential link between cellular metabolism and chromatin regulation.

  14. Embedded-monolith armor

    DOEpatents

    McElfresh, Michael W.; Groves, Scott E; Moffet, Mitchell L.; Martin, Louis P.

    2016-07-19

    A lightweight armor system utilizing a face section having a multiplicity of monoliths embedded in a matrix supported on low density foam. The face section is supported with a strong stiff backing plate. The backing plate is mounted on a spall plate.

  15. The sweet potato ADP-glucose pyrophosphorylase gene (ibAGP1) promoter confers high-level expression of the GUS reporter gene in the potato tuber.

    PubMed

    Kim, Tae-Won; Goo, Young-Min; Lee, Cheol-Ho; Lee, Byung-Hyun; Bae, Jung-Myung; Lee, Shin-Woo

    2009-10-01

    Molecular farming refers to the process of creating bioengineered plants with the capability of producing potentially valuable products, such as drugs, vaccines, and chemicals. We have investigated the potential of the sweet potato ADP-glucose pyrophosphorylase gene (ibAGP1) promoter and its transit peptide (TP) as an expression system for the mass production of foreign proteins in potato. The ibAGP1 promoter and its TP sequence were transformed into potato along with beta-glucuronidase (GUS) as a reporter gene, and GUS activity was subsequently analyzed in the transgenic potato plants. In tuber tissues, GUS activity in transgenic plants carrying only the ibAGP1 promoter (ibAGP1::GUS) increased up to 15.6-fold compared with that of transgenic plants carrying only the CaMV35S promoter (CaMV35S::GUS). GUS activity in transgenic plants was further enhanced by the addition of the sweetpotato TP to the recombinant vector (ibAGP1::TP::GUS), with tuber tissues showing a 26-fold increase in activity compared with that in the CaMV35S::GUS-transgenic lines. In leaf tissues, the levels of GUS activity found in ibAGP1::GUS-transgenic lines were similar to those in CaMV35S::GUS-lines, but they were significantly enhanced in ibAGP1::TP::GUS-lines. GUS activity gradually increased with increasing tuber diameter in ibAGP1::GUS-transgenic plants, reaching a maximum level when the tuber was 35 mm in diameter. In contrast, extremely elevated levels of GUS activity - up to about 10-fold higher than that found in CaMV35S::GUS-lines - were found in ibAGP1::TP::GUS-transgenic lines at a much earlier stage of tuber development (diameter 4 mm), and these higher levels were maintained throughout the entire tuber developmental stage. These results suggest that the sweetpotato ibAGP1 promoter and its TP are a potentially strong foreign gene expression system that can be used for molecular farming in potato plants.

  16. The sweet potato ADP-glucose pyrophosphorylase gene (ibAGP1) promoter confers high-level expression of the GUS reporter gene in the potato tuber.

    PubMed

    Kim, Tae-Won; Goo, Young-Min; Lee, Cheol-Ho; Lee, Byung-Hyun; Bae, Jung-Myung; Lee, Shin-Woo

    2009-10-01

    Molecular farming refers to the process of creating bioengineered plants with the capability of producing potentially valuable products, such as drugs, vaccines, and chemicals. We have investigated the potential of the sweet potato ADP-glucose pyrophosphorylase gene (ibAGP1) promoter and its transit peptide (TP) as an expression system for the mass production of foreign proteins in potato. The ibAGP1 promoter and its TP sequence were transformed into potato along with beta-glucuronidase (GUS) as a reporter gene, and GUS activity was subsequently analyzed in the transgenic potato plants. In tuber tissues, GUS activity in transgenic plants carrying only the ibAGP1 promoter (ibAGP1::GUS) increased up to 15.6-fold compared with that of transgenic plants carrying only the CaMV35S promoter (CaMV35S::GUS). GUS activity in transgenic plants was further enhanced by the addition of the sweetpotato TP to the recombinant vector (ibAGP1::TP::GUS), with tuber tissues showing a 26-fold increase in activity compared with that in the CaMV35S::GUS-transgenic lines. In leaf tissues, the levels of GUS activity found in ibAGP1::GUS-transgenic lines were similar to those in CaMV35S::GUS-lines, but they were significantly enhanced in ibAGP1::TP::GUS-lines. GUS activity gradually increased with increasing tuber diameter in ibAGP1::GUS-transgenic plants, reaching a maximum level when the tuber was 35 mm in diameter. In contrast, extremely elevated levels of GUS activity - up to about 10-fold higher than that found in CaMV35S::GUS-lines - were found in ibAGP1::TP::GUS-transgenic lines at a much earlier stage of tuber development (diameter 4 mm), and these higher levels were maintained throughout the entire tuber developmental stage. These results suggest that the sweetpotato ibAGP1 promoter and its TP are a potentially strong foreign gene expression system that can be used for molecular farming in potato plants. PMID:19819408

  17. Pore volume accessibility of particulate and monolithic stationary phases.

    PubMed

    Urban, Jiří

    2015-05-29

    A chromatographic characterization of pore volume accessibility for both particulate and monolithic stationary phases is presented. Size-exclusion calibration curves have been used to determine the pore volume fraction that is accessible for six alkylbenzenes and twelve polystyrene standards in tetrahydrofuran as the mobile phase. Accessible porosity has been then correlated with the size of the pores from which individual compounds are just excluded. I have determined pore volume accessibility of commercially available columns packed with fully and superficially porous particles, as well as with silica-based monolithic stationary phase. I also have investigated pore accessibility of polymer-based monolithic stationary phases. Suggested protocol is used to characterize pore formation at the early stage of the polymerization, to evaluate an extent of hypercrosslinking during modification of pore surface, and to characterize the pore accessibility of monolithic stationary phases hypercrosslinked after an early termination of polymerization reaction. Pore volume accessibility was also correlated to column efficiency of both particulate and monolithic stationary phases. PMID:25892635

  18. Paromomycin Derived from Streptomyces sp. AG-P 1441 Induces Resistance against Two Major Pathogens of Chili Pepper.

    PubMed

    Balaraju, Kotnala; Kim, Chang-Jin; Park, Dong-Jin; Nam, Ki-Woong; Zhang, Kecheng; Sang, Mee Kyung; Park, Kyungseok

    2016-09-28

    This is the first report that paromomycin, an antibiotic derived from Streptomyces sp. AG-P 1441 (AG-P 1441), controlled Phytophthora blight and soft rot diseases caused by Phytophthora capsici and Pectobacterium carotovorum, respectively, in chili pepper (Capsicum annum L.). Chili pepper plants treated with paromomycin by foliar spray or soil drenching 7 days prior to inoculation with P. capsici zoospores showed significant (p < 0.05) reduction in disease severity (%) when compared with untreated control plants. The disease severity of Phytophthora blight was recorded as 8% and 50% for foliar spray and soil drench, respectively, at 1.0 ppm of paromomycin, compared with untreated control, where disease severity was 83% and 100% by foliar spray and soil drench, respectively. A greater reduction of soft rot lesion areas per leaf disk was observed in treated plants using paromomycin (1.0 μg/ml) by infiltration or soil drench in comparison with untreated control plants. Paromomycin treatment did not negatively affect the growth of chili pepper. Furthermore, the treatment slightly promoted growth; this growth was supported by increased chlorophyll content in paromomycin-treated chili pepper plants. Additionally, paromomycin likely induced resistance as confirmed by the expression of pathogenesis-related (PR) genes: PR-1, β-1,3-glucanase, chitinase, PR-4, peroxidase, and PR-10, which enhanced plant defense against P. capsici in chili pepper. This finding indicates that AG-P 1441 plays a role in pathogen resistance upon the activation of defense genes, by secretion of the plant resistance elicitor, paromomycin. PMID:27291677

  19. Monolithic MACS micro resonators

    NASA Astrophysics Data System (ADS)

    Lehmann-Horn, J. A.; Jacquinot, J.-F.; Ginefri, J. C.; Bonhomme, C.; Sakellariou, D.

    2016-10-01

    Magic Angle Coil Spinning (MACS) aids improving the intrinsically low NMR sensitivity of heterogeneous microscopic samples. We report on the design and testing of a new type of monolithic 2D MACS resonators to overcome known limitations of conventional micro coils. The resonators' conductors were printed on dielectric substrate and tuned without utilizing lumped element capacitors. Self-resonance conditions have been computed by a hybrid FEM-MoM technique. Preliminary results reported here indicate robust mechanical stability, reduced eddy currents heating and negligible susceptibility effects. The gain in B1 /√{ P } is in agreement with the NMR sensitivity enhancement according to the principle of reciprocity. A sensitivity enhancement larger than 3 has been achieved in a monolithic micro resonator inside a standard 4 mm rotor at 500 MHz. These 2D resonators could offer higher performance micro-detection and ease of use of heterogeneous microscopic substances such as biomedical samples, microscopic specimens and thin film materials.

  20. Monolithic MACS micro resonators.

    PubMed

    Lehmann-Horn, J A; Jacquinot, J-F; Ginefri, J C; Bonhomme, C; Sakellariou, D

    2016-10-01

    Magic Angle Coil Spinning (MACS) aids improving the intrinsically low NMR sensitivity of heterogeneous microscopic samples. We report on the design and testing of a new type of monolithic 2D MACS resonators to overcome known limitations of conventional micro coils. The resonators' conductors were printed on dielectric substrate and tuned without utilizing lumped element capacitors. Self-resonance conditions have been computed by a hybrid FEM-MoM technique. Preliminary results reported here indicate robust mechanical stability, reduced eddy currents heating and negligible susceptibility effects. The gain in B1/P is in agreement with the NMR sensitivity enhancement according to the principle of reciprocity. A sensitivity enhancement larger than 3 has been achieved in a monolithic micro resonator inside a standard 4mm rotor at 500MHz. These 2D resonators could offer higher performance micro-detection and ease of use of heterogeneous microscopic substances such as biomedical samples, microscopic specimens and thin film materials. PMID:27544845

  1. Monolithic Optoelectronic Integrated Circuit

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul B.; Walters, Wayne; Gustafsen, Jerry; Bendett, Mark

    1990-01-01

    Monolithic optoelectronic integrated circuit (OEIC) receives single digitally modulated input light signal via optical fiber and converts it into 16-channel electrical output signal. Potentially useful in any system in which digital data must be transmitted serially at high rates, then decoded into and used in parallel format at destination. Applications include transmission and decoding of control signals to phase shifters in phased-array antennas and also communication of data between computers and peripheral equipment in local-area networks.

  2. Monolithic Millimeter Wave Oscillator

    NASA Astrophysics Data System (ADS)

    Wang, Nan-Lei

    There is an increasing interest in the millimeter -wave spectrum for use in communications and for military and scientific applications. The concept of monolithic integration aims to produce very-high-frequency circuits in a more reliable, reproducible way than conventional electronics, and also at lower cost, with smaller size and lighter weight. In this thesis, a negative resistance device is integrated monolithically with a resonator to produce an effective oscillator. This work fills the void resulting from the exclusion of the local oscillator from the monolithic millimeter-wave integrated circuit (MMMIC) receiver design. For convenience a microwave frequency model was used to design the resonator circuit. A 5 GHz hybrid oscillator was first fabricated to test the design; the necessary GaAs process technology was developed for the fabrication. Negative resistance devices and oscillator theory were studied, and a simple but practical model of the Gunn diode was devised to solve the impedance matching problem. Monolithic oscillators at the Ka band (35 GHz) were built and refined. All devices operated in CW mode. By means of an electric-field probe, the output power was coupled into a metallic waveguide for measurement purposes. The best result was 3.63 mW of power output, the highest efficiency was 0.43% and the frequency stability was better than 10-4. In the future, an IMPATT diode could replace the Gunn device to give much higher power and efficiency. A varactor-tuned circuit also suitable for large-scale integration is under study.

  3. Monolith electroplating process

    DOEpatents

    Agarrwal, Rajev R.

    2001-01-01

    An electroplating process for preparing a monolith metal layer over a polycrystalline base metal and the plated monolith product. A monolith layer has a variable thickness of one crystal. The process is typically carried in molten salts electrolytes, such as the halide salts under an inert atmosphere at an elevated temperature, and over deposition time periods and film thickness sufficient to sinter and recrystallize completely the nucleating metal particles into one single crystal or crystals having very large grains. In the process, a close-packed film of submicron particle (20) is formed on a suitable substrate at an elevated temperature. The temperature has the significance of annealing particles as they are formed, and substrates on which the particles can populate are desirable. As the packed bed thickens, the submicron particles develop necks (21) and as they merge into each other shrinkage (22) occurs. Then as micropores also close (23) by surface tension, metal density is reached and the film consists of unstable metal grain (24) that at high enough temperature recrystallize (25) and recrystallized grains grow into an annealed single crystal over the electroplating time span. While cadmium was used in the experimental work, other soft metals may be used.

  4. Transparent monolithic metal ion containing nanophase aerogels

    SciTech Connect

    Risen, W. M., Jr.; Hu, X.; Ji, S.; Littrell, K.

    1999-12-01

    The formation of monolithic and transparent transition metal containing aerogels has been achieved through cooperative interactions of high molecular weight functionalized carbohydrates and silica precursors, which strongly influence the kinetics of gelation. After initial gelation, subsequent modification of the ligating character of the system, coordination of the group VIII metal ions, and supercritical extraction afford the aerogels. The structures at the nanophase level have been probed by photon and electron transmission and neutron scattering techniques to help elucidate the basis for structural integrity together with the small entity sizes that permit transparency in the visible range. They also help with understanding the chemical reactivities of the metal-containing sites in these very high surface area materials. These results are discussed in connection with new reaction studies.

  5. dbAARD & AGP: A computational pipeline for the prediction of genes associated with age related disorders.

    PubMed

    Srivastava, Isha; Gahlot, Lokesh Kumar; Khurana, Pooja; Hasija, Yasha

    2016-04-01

    The atrocious behavioral and physiological shift with aging accelerate occurrence of deleterious disorders. Contemporary research is focused at uncovering the role of genetic associations in age-related disorders (ARDs). While the completion of the Human Genome Project and the HapMap project has generated huge amount of data on genetic variations; Genome-Wide Association Studies (GWAS) have identified genetic variations, essentially SNPs associated with several disorders including ARDs. However, a repository that houses all such ARD associations is lacking. The present work is aimed at filling this void. A database, dbAARD (database of Aging and Age Related Disorders) has been developed which hosts information on more than 3000 genetic variations significantly (p-value <0.05) associated with 51 ARDs. Furthermore, a machine learning based gene prediction tool AGP (Age Related Disorders Gene Prediction) has been constructed by employing rotation forest algorithm, to prioritize genes associated with ARDs. The tool achieved an overall accuracy in terms of precision 75%, recall 76%, F-measure 76% and AUC 0.85. Both the web resources have been made available online at http://genomeinformatics.dce.edu/dbAARD/ and http://genomeinformatics.dce.edu/AGP/ respectively for easy retrieval and usage by the scientific community. We believe that this work may facilitate the analysis of plethora of variants associated with ARDs and provide cues for deciphering the biology of aging. PMID:26836976

  6. Facile fabrication of high-quality Ag/PS coaxial nanocables based on the mixed mode of soft/hard templates

    PubMed Central

    Wan, Mimi; Zhao, Wenbo; Peng, Fang; Wang, Qi; Xu, Ping; Mao, Chun; Shen, Jian

    2016-01-01

    A new kind of high-quality Ag/PS coaxial nanocables can be facilely synthesized by using soft/hard templates method. In order to effectively introduce Ag sources into porous polystyrene (PS) nanotubes which were trapped in porous anodic aluminum oxide (AAO) hard template, Pluronic F127 (F127) was used as guiding agent, soft template and reductant. Meanwhile, ethylene glycol solution was also used as solvent and co-reducing agent to assist in the formation of silver nanowires. The influences of concentration of F127 and reducing reaction time on the formation of Ag/PS coaxial nanocables were discussed. Results indicated that the high-quality Ag/PS coaxial nanocables can be obtained by the mixed mode of soft/hard templates under optimized conditions. This strategy is expected to be extended to design more metal/polymer coaxial nanocables for the benefit of creation of complex and functional nanoarchitectures and components. PMID:27477888

  7. Facile fabrication of high-quality Ag/PS coaxial nanocables based on the mixed mode of soft/hard templates

    NASA Astrophysics Data System (ADS)

    Wan, Mimi; Zhao, Wenbo; Peng, Fang; Wang, Qi; Xu, Ping; Mao, Chun; Shen, Jian

    2016-08-01

    A new kind of high-quality Ag/PS coaxial nanocables can be facilely synthesized by using soft/hard templates method. In order to effectively introduce Ag sources into porous polystyrene (PS) nanotubes which were trapped in porous anodic aluminum oxide (AAO) hard template, Pluronic F127 (F127) was used as guiding agent, soft template and reductant. Meanwhile, ethylene glycol solution was also used as solvent and co-reducing agent to assist in the formation of silver nanowires. The influences of concentration of F127 and reducing reaction time on the formation of Ag/PS coaxial nanocables were discussed. Results indicated that the high-quality Ag/PS coaxial nanocables can be obtained by the mixed mode of soft/hard templates under optimized conditions. This strategy is expected to be extended to design more metal/polymer coaxial nanocables for the benefit of creation of complex and functional nanoarchitectures and components.

  8. Monolithic tandem solar cell

    DOEpatents

    Wanlass, Mark W.

    1991-01-01

    A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surface of the InP substrate, and (c) a second photoactive subcell on the first subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched. The solar cell can be provided as a two-terminal device or a three-terminal device.

  9. Monolithic microfluidic concentrators and mixers

    DOEpatents

    Frechet, Jean M.; Svec, Frantisek; Yu, Cong; Rohr, Thomas

    2005-05-03

    Microfluidic devices comprising porous monolithic polymer for concentration, extraction or mixing of fluids. A method for in situ preparation of monolithic polymers by in situ initiated polymerization of polymer precursors within microchannels of a microfluidic device and their use for solid phase extraction (SPE), preconcentration, concentration and mixing.

  10. [Modification of sol-gel hybrid monolith and its application in determination of polycyclic aromatic hydrocarbons].

    PubMed

    Yang, Rancun; Zhang, Shaowen; Sun, Yu'an

    2015-05-01

    A C6-silica hybrid monolithic column was prepared by click reaction with capillary silica monolith. Firstly, an azide-functionalized silica monolithic column was synthesized via sol-gel reaction with tetramethoxysilane (TMOS) and 3-azidopropyltrimethoxysilane (N3PTMS). Then 1-hexyne was covalently immobilized on the capillary monolith by the "azide-alkyne" click reaction to form C6-silica hybrid monolithic column. As an extraction media of polycyclic aromatic hydrocarbons (PAHs), the conditions for the preparation and modification of the monolith were carefully investigated according to the extraction efficiency. The enrichment factors for typical PAHs: naphthalene, phenanthrene, pyrene and benzo a pyrene finally reached 95.9, 14.2, 103.2 and 57.8, respectively. The relative standard deviations (RSDs) for the extraction were lower than 5.5% (intra-day, t = 8) and 7.3% (inter-day, n = 10). Based on the in-tube solid phase microextraction (in-tube SPME), a new determination method for 16 PAHs was developed with high performance liquid chromatography (HPLC). The limits of detection (LODs, SN = 3) were 0.08-3.72 µg/L and the limits of quantification (LOQs, S/N = 10) were 0.26-12.40 µg/L for the PAHs. The spiked recoveries for the PAHs in soil samples were between 82.4% and 110.6% with the RSDs (n = 3) of 2.6%-7.9%. Comparison with the method of United States Environmental Protection Agency (U. S. EPA) for the PAIs determination in soil samples, the results showed good accuracy and high consistency. And the high extraction efficiency with high sensitivity and convenience was also demonstrated in the applications of the new approach.

  11. Polyurea-Based Aerogel Monoliths and Composites

    NASA Technical Reports Server (NTRS)

    Lee, Je Kyun

    2012-01-01

    aerogel insulation material was developed that will provide superior thermal insulation and inherent radiation protection for government and commercial applications. The rubbery polyureabased aerogel exhibits little dustiness, good flexibility and toughness, and durability typical of the parent polyurea polymer, yet with the low density and superior insulation properties associated with aerogels. The thermal conductivity values of polyurea-based aerogels at lower temperature under vacuum pressures are very low and better than that of silica aerogels. Flexible, rubbery polyurea-based aerogels are able to overcome the weak and brittle nature of conventional inorganic and organic aerogels, including polyisocyanurate aerogels, which are generally prepared with the one similar component to polyurethane rubber aerogels. Additionally, with higher content of hydrogen in their structures, the polyurea rubber-based aerogels will also provide inherently better radiation protection than those of inorganic and carbon aerogels. The aerogel materials also demonstrate good hydrophobicity due to their hydrocarbon molecular structure. There are several strategies to overcoming the drawbacks associated with the weakness and brittleness of silica aerogels. Development of the flexible fiber-reinforced silica aerogel composite blanket has proven to be one promising approach, providing a conveniently fielded form factor that is relatively robust in industrial environments compared to silica aerogel monoliths. However, the flexible, silica aerogel composites still have a brittle, dusty character that may be undesirable, or even intolerable, in certain application environments. Although the cross - linked organic aerogels, such as resorcinol- formaldehyde (RF), polyisocyanurate, and cellulose aerogels, show very high impact strength, they are also very brittle with little elongation (i.e., less rubbery). Also, silica and carbon aerogels are less efficient radiation shielding materials due

  12. Design of monoliths through their mechanical properties.

    PubMed

    Podgornik, Aleš; Savnik, Aleš; Jančar, Janez; Krajnc, Nika Lendero

    2014-03-14

    Chromatographic monoliths have several interesting properties making them attractive supports for analytics but also for purification, especially of large biomolecules and bioassemblies. Although many of monolith features were thoroughly investigated, there is no data available to predict how monolith mechanical properties affect its chromatographic performance. In this work, we investigated the effect of porosity, pore size and chemical modification on methacrylate monolith compression modulus. While a linear correlation between pore size and compression modulus was found, the effect of porosity was highly exponential. Through these correlations it was concluded that chemical modification affects monolith porosity without changing the monolith skeleton integrity. Mathematical model to describe the change of monolith permeability as a function of monolith compression modulus was derived and successfully validated for monoliths of different geometries and pore sizes. It enables the prediction of pressure drop increase due to monolith compressibility for any monolith structural characteristics, such as geometry, porosity, pore size or mobile phase properties like viscosity or flow rate, based solely on the data of compression modulus and structural data of non-compressed monolith. Furthermore, it enables simple determination of monolith pore size at which monolith compressibility is the smallest and the most robust performance is expected. Data of monolith compression modulus in combination with developed mathematical model can therefore be used for the prediction of monolith permeability during its implementation but also to accelerate the design of novel chromatographic monoliths with desired hydrodynamic properties for particular application.

  13. Monolithic THz Frequency Multipliers

    NASA Technical Reports Server (NTRS)

    Erickson, N. R.; Narayanan, G.; Grosslein, R. M.; Martin, S.; Mehdi, I.; Smith, P.; Coulomb, M.; DeMartinez, G.

    2001-01-01

    Frequency multipliers are required as local oscillator sources for frequencies up to 2.7 THz for FIRST and airborne applications. Multipliers at these frequencies have not previously been demonstrated, and the object of this work was to show whether such circuits are really practical. A practical circuit is one which not only performs as well as is required, but also can be replicated in a time that is feasible. As the frequency of circuits is increased, the difficulties in fabrication and assembly increase rapidly. Building all of the circuit on GaAs as a monolithic circuit is highly desirable to minimize the complexity of assembly, but at the highest frequencies, even a complete monolithic circuit is extremely small, and presents serious handling difficulty. This is compounded by the requirement for a very thin substrate. Assembly can become very difficult because of handling problems and critical placement. It is very desirable to make the chip big enough to that it can be seen without magnification, and strong enough that it may be picked up with tweezers. Machined blocks to house the chips present an additional challenge. Blocks with complex features are very expensive, and these also imply very critical assembly of the parts. It would be much better if the features in the block were as simple as possible and non-critical to the function of the chip. In particular, grounding and other electrical interfaces should be done in a manner that is highly reproducible.

  14. Monolithic ballasted penetrator

    DOEpatents

    Hickerson, Jr., James P.; Zanner, Frank J.; Baldwin, Michael D.; Maguire, Michael C.

    2001-01-01

    The present invention is a monolithic ballasted penetrator capable of delivering a working payload to a hardened target, such as reinforced concrete. The invention includes a ballast made from a dense heavy material insert and a monolithic case extending along an axis and consisting of a high-strength steel alloy. The case includes a nose end containing a hollow portion in which the ballast is nearly completely surrounded so that no movement of the ballast relative to the case is possible during impact with a hard target. The case is cast around the ballast, joining the two parts together. The ballast may contain concentric grooves or protrusions that improve joint strength between the case and ballast. The case further includes a second hollow portion; between the ballast and base, which has a payload fastened within this portion. The penetrator can be used to carry instrumentation to measure the geologic character of the earth, or properties of arctic ice, as they pass through it.

  15. Chemically Etched Open Tubular and Monolithic Emitters for Nanoelectrospray Ionization Mass Spectrometry

    SciTech Connect

    Kelly, Ryan T.; Page, Jason S.; Luo, Quanzhou; Moore, Ronald J.; Orton, Daniel J.; Tang, Keqi; Smith, Richard D.

    2006-11-15

    We have developed a new procedure for fabricating fused silica emitters for electrospray ionization-mass spectrometry (ESI-MS) in which the end of a bare fused silica capillary is immersed into aqueous hydrofluoric acid, and water is pumped through the capillary to prevent etching of the interior. Surface tension causes the etchant to climb the capillary exterior, and the etch rate in the resulting meniscus decreases as a function of distance from the bulk solution. Etching continues until the silica touching the hydrofluoric acid reservoir is completely removed, essentially stopping the etch process. The resulting emitters have no internal taper, making them much less prone to clogging compared to e.g. pulled emitters. The high aspect ratios and extremely thin walls at the orifice facilitate very low flow rate operation; stable ESI-MS signals were obtained for model analytes from 5-μm-diameter emitters at a flow rate of 5 nL/min with a high degree of inter-emitter reproducibility. In extensive evaluation, the etched emitters were found to enable approximately four times as many LC-MS analyses of proteomic samples before failing compared with conventional pulled emitters. The fabrication procedure was also employed to taper the ends of polymer monolith-containing silica capillaries for use as ESI emitters. In contrast to previous work, the monolithic material protrudes beyond the fused silica capillaries, improving the monolith-assisted electrospray process.

  16. Tunable optical reflectance using a monolithic encapsulated grating

    NASA Astrophysics Data System (ADS)

    Sang, Tian; Chen, Guoqing; Wang, Yueke; Wang, Benxin; Jiang, Wenwen; Zhao, Tianzhuo; Cai, Shaohong

    2016-09-01

    Tunable optical reflectance using a monolithic encapsulated grating in fused silica is presented based on the guided-mode resonance (GMR) effect. The resonance location can be altered by slightly varying the thickness of the top layer. For small thickness of the grating layer, the variation of the grating thickness can be tailored to create variable optical reflectance at the same operating wavelength with the filter linewidth and the reflection sidebands kept almost the same. By proper choosing the grating thickness, the novel dual functional device that combines functions of narrowband filtering and three-port beam splitting in the resonance domain can be obtained using the monolithic encapsulated grating. Multiline reflection filters can be obtained by increasing the thickness of the top layer, and tunable reflectivity for multiple operating wavelengths can be obtained by changing the grating thickness.

  17. Recommendations for standardizing glucose reporting and analysis to optimize clinical decision making in diabetes: the Ambulatory Glucose Profile (AGP).

    PubMed

    Bergenstal, Richard M; Ahmann, Andrew J; Bailey, Timothy; Beck, Roy W; Bissen, Joan; Buckingham, Bruce; Deeb, Larry; Dolin, Robert H; Garg, Satish K; Goland, Robin; Hirsch, Irl B; Klonoff, David C; Kruger, Davida F; Matfin, Glenn; Mazze, Roger S; Olson, Beth A; Parkin, Christopher; Peters, Anne; Powers, Margaret A; Rodriguez, Henry; Southerland, Phil; Strock, Ellie S; Tamborlane, William; Wesley, David M

    2013-03-01

    Abstract Underutilization of glucose data and lack of easy and standardized glucose data collection, analysis, visualization, and guided clinical decision making are key contributors to poor glycemic control among individuals with type 1 diabetes. An expert panel of diabetes specialists, facilitated by the International Diabetes Center and sponsored by the Helmsley Charitable Trust, met in 2012 to discuss recommendations for standardization of analysis and presentation of glucose monitoring data, with the initial focus on data derived from CGM systems. The panel members were introduced to a universal software report, the Ambulatory Glucose Profile (AGP), and asked to provide feedback on its content and functionality, both as a research tool and in clinical settings. This paper provides a summary of the topics and issues discussed during the meeting and presents recommendations from the expert panel regarding the need to standardize glucose profile summary metrics and the value of a uniform glucose report to aid clinicians, researchers, and patients.

  18. Monolithic microchannel heatsink

    DOEpatents

    Benett, William J.; Beach, Raymond J.; Ciarlo, Dino R.

    1996-01-01

    A silicon wafer has slots sawn in it that allow diode laser bars to be mounted in contact with the silicon. Microchannels are etched into the back of the wafer to provide cooling of the diode bars. To facilitate getting the channels close to the diode bars, the channels are rotated from an angle perpendicular to the diode bars which allows increased penetration between the mounted diode bars. This invention enables the fabrication of monolithic silicon microchannel heatsinks for laser diodes. The heatsinks have low thermal resistance because of the close proximity of the microchannels to the laser diode being cooled. This allows high average power operation of two-dimensional laser diode arrays that have a high density of laser diode bars and therefore high optical power density.

  19. Monolithic microchannel heatsink

    DOEpatents

    Benett, W.J.; Beach, R.J.; Ciarlo, D.R.

    1996-08-20

    A silicon wafer has slots sawn in it that allow diode laser bars to be mounted in contact with the silicon. Microchannels are etched into the back of the wafer to provide cooling of the diode bars. To facilitate getting the channels close to the diode bars, the channels are rotated from an angle perpendicular to the diode bars which allows increased penetration between the mounted diode bars. This invention enables the fabrication of monolithic silicon microchannel heatsinks for laser diodes. The heatsinks have low thermal resistance because of the close proximity of the microchannels to the laser diode being cooled. This allows high average power operation of two-dimensional laser diode arrays that have a high density of laser diode bars and therefore high optical power density. 9 figs.

  20. Monolithic freeform element

    NASA Astrophysics Data System (ADS)

    Kiontke, Sven R.

    2015-09-01

    For 10 years there has been the asphere as one of the new products to be accepted by the market. All parts of the chain design, production and measurement needed to learn how to treat the asphere and what it is helpful for. The aspheric optical element now is established and accepted as an equal optical element between other as a fast growing part of all the optical elements. Now we are focusing onto the next new element with a lot of potential, the optical freeform surface. Manufacturing results will be shown for fully tolerance optic including manufacturing, setup and optics configurations including measurement setup. The element itself is a monolith consisting of several optical surfaces that have to be aligned properly to each other. The freeform surface is measured for surface form tolerance (irregularity, slope, Zernike, PV).

  1. Monolithically compatible impedance measurement

    DOEpatents

    Ericson, Milton Nance; Holcomb, David Eugene

    2002-01-01

    A monolithic sensor includes a reference channel and at least one sensing channel. Each sensing channel has an oscillator and a counter driven by the oscillator. The reference channel and the at least one sensing channel being formed integrally with a substrate and intimately nested with one another on the substrate. Thus, the oscillator and the counter have matched component values and temperature coefficients. A frequency determining component of the sensing oscillator is formed integrally with the substrate and has an impedance parameter which varies with an environmental parameter to be measured by the sensor. A gating control is responsive to an output signal generated by the reference channel, for terminating counting in the at least one sensing channel at an output count, whereby the output count is indicative of the environmental parameter, and successive ones of the output counts are indicative of changes in the environmental parameter.

  2. Monolithic microcircuit techniques and processes

    NASA Technical Reports Server (NTRS)

    Kennedy, B. W.

    1972-01-01

    Brief discussions of the techniques used to make dielectric and metal thin film depositions for monolithic circuits are presented. Silicon nitride deposition and the properties of silicon nitride films are discussed. Deposition of dichlorosilane and thermally grown silicon dioxide are reported. The deposition and thermal densification of borosilicate, aluminosilicate, and phosphosilicate glasses are discussed. Metallization for monolithic circuits and the characteristics of thin films are also included.

  3. Robust monolithic ultraviolet interferometer for the SHIMMER instrument on STPSat-1

    NASA Astrophysics Data System (ADS)

    Harlander, John M.; Roesler, Fred L.; Englert, Christoph R.; Cardon, Joel G.; Conway, Robert R.; Brown, Charles M.; Wimperis, Jeff

    2003-05-01

    We describe the design, fabrication, and testing of a monolithic interferometer consisting entirely of optically contacted fused-silica optical elements that are assembled, adjusted, and permanently bonded in place. The interferometer is part of a spatial heterodyne spectrometer (SHS) [SHIMMER (Spatial Heterodyne Imager for Mesospheric Radicals)] that will be used for near-ultraviolet high-spectral-resolution limb imaging of OH solar resonance fluorescence from low Earth orbit aboard the satellite STPSat-1 scheduled for launch in 2006. The stability of the monolith coupled with the relaxed tolerances on optical quality and alignment inherent to SHS make this new instrument extremely robust and especially attractive for applications in harsh environments.

  4. Preparation and characterization of alkyl methacrylate-based monolithic columns for capillary gas chromatography applications.

    PubMed

    Yusuf, Kareem; Aqel, Ahmad; A L Othman, Zeid; Badjah-Hadj-Ahmed, Ahmed Yacine

    2013-08-01

    Gas chromatography (GC) is considered the least common application of both polymer and silica-based monolithic columns. This study describes the fabrication of alkyl methacrylate monolithic materials for use as stationary phases in capillary gas chromatography. Following the deactivation of the capillary surface with 3-(trimethoxysilyl)propyl methacrylate (TMSM), the monoliths were formed by the co-polymerization of either hexyl methacrylate (HMA) or lauryl methacrylate (LMA) with different percentage of ethylene glycol dimethacrylate (EDMA) in presence of an initiator (azobisisobutyronitrile, AIBN) and a mixture of porogens include 1-propanol, 1,4-butanediol and water. The monoliths were prepared in 500mm length capillaries possessing inner diameters of 250μm. The efficiencies of the monolithic columns for low molecular weight compounds significantly improved as the percentage of crosslinker was increased, because of the greater proportion of pores less than 50nm. The columns containing lower percentages of crosslinker were able to rapidly separate a series of 8 alkane members in 0.7min, but the separation was less efficient for the light alkanes. Columns prepared with the lauryl methacrylate monomer yielded a different morphology for the monolith-interconnected channels. The channels were more branched, which increased the separation time, and unlike the other columns, allowed for temperature programming.

  5. Tailoring the morphology of methacrylate ester-based monoliths for optimum efficiency in liquid chromatography.

    PubMed

    Eeltink, Sebastiaan; Herrero-Martinez, José Manuel; Rozing, Gerard P; Schoenmakers, Peter J; Kok, Wim Th

    2005-11-15

    Methacrylate ester-based monolithic stationary phases were prepared in situ in fused-silica capillaries and simultaneously in vials. The influence of the composition of the polymerization mixture on the morphology was studied with mercury intrusion porosimetry, scanning electron microscopy, and nitrogen adsorption measurements. A high-density porous polymeric material with a unimodal pore-size distribution was prepared with 40 wt % monomers and 60 wt % solvent in the mixture. A low-density material, prepared with a 20:80 ratio of monomers versus pore-forming solvent, showed a bimodal pore-size distribution and a much finer structure than the high-density monolith. The characteristic pore size could be controlled by changing the ratio of pore-forming solvents. With increasing solvent polarity, both the pore size and the dimension of the globules increased. The best efficiency in the CEC mode was obtained with an average pore size of 600 nm. Low-density monoliths exhibited lower A- and C-terms than high-density monoliths. With the optimal monolithic material, a minimum plate height of 5 mum could be obtained. The low-density monolith also performed better in the HPLC mode, giving a minimum plate height of 15 mum and a much higher flow permeability than that of the high-density material. PMID:16285684

  6. Monolithic metal oxide transistors.

    PubMed

    Choi, Yongsuk; Park, Won-Yeong; Kang, Moon Sung; Yi, Gi-Ra; Lee, Jun-Young; Kim, Yong-Hoon; Cho, Jeong Ho

    2015-04-28

    We devised a simple transparent metal oxide thin film transistor architecture composed of only two component materials, an amorphous metal oxide and ion gel gate dielectric, which could be entirely assembled using room-temperature processes on a plastic substrate. The geometry cleverly takes advantage of the unique characteristics of the two components. An oxide layer is metallized upon exposure to plasma, leading to the formation of a monolithic source-channel-drain oxide layer, and the ion gel gate dielectric is used to gate the transistor channel effectively at low voltages through a coplanar gate. We confirmed that the method is generally applicable to a variety of sol-gel-processed amorphous metal oxides, including indium oxide, indium zinc oxide, and indium gallium zinc oxide. An inverter NOT logic device was assembled using the resulting devices as a proof of concept demonstration of the applicability of the devices to logic circuits. The favorable characteristics of these devices, including (i) the simplicity of the device structure with only two components, (ii) the benign fabrication processes at room temperature, (iii) the low-voltage operation under 2 V, and (iv) the excellent and stable electrical performances, together support the application of these devices to low-cost portable gadgets, i.e., cheap electronics. PMID:25777338

  7. Monolithic afocal telescope

    NASA Technical Reports Server (NTRS)

    Roberts, William T. (Inventor)

    2010-01-01

    An afocal monolithic optical element formed of a shallow cylinder of optical material (glass, polymer, etc.) with fast aspheric surfaces, nominally confocal paraboloids, configured on the front and back surfaces. The front surface is substantially planar, and this lends itself to deposition of multi-layer stacks of thin dielectric and metal films to create a filter for rejecting out-of-band light. However, an aspheric section (for example, a paraboloid) can either be ground into a small area of this surface (for a Cassegrain-type telescope) or attached to the planar surface (for a Gregorian-type telescope). This aspheric section of the surface is then silvered to create the telescope's secondary mirror. The rear surface of the cylinder is figured into a steep, convex asphere (again, a paraboloid in the examples), and also made reflective to form the telescope's primary mirror. A small section of the rear surface (approximately the size of the secondary obscuration, depending on the required field of the telescope) is ground flat to provide an unpowered surface through which the collimated light beam can exit the optical element. This portion of the rear surface is made to transmit the light concentrated by the reflective surfaces, and can support the deposition of a spectral filter.

  8. Factorizing monolithic applications

    SciTech Connect

    Hall, J.H.; Ankeny, L.A.; Clancy, S.P.

    1998-12-31

    The Blanca project is part of the US Department of Energy`s (DOE) Accelerated Strategic Computing Initiative (ASCI), which focuses on Science-Based Stockpile Stewardship through the large-scale simulation of multi-physics, multi-dimensional problems. Blanca is the only Los Alamos National Laboratory (LANL)-based ASCI project that is written entirely in C++. Tecolote, a new framework used in developing Blanca physics codes, provides an infrastructure for gluing together any number of components; this framework is then used to create applications that encompass a wide variety of physics models, numerical solution options, and underlying data storage schemes. The advantage of this approach is that only the essential components for the given model need be activated at runtime. Tecolote has been designed for code re-use and to isolate the computer science mechanics from the physics aspects as much as possible -- allowing physics model developers to write algorithms in a style quite similar to the underlying physics equations that govern the computational physics. This paper describes the advantages of component architectures and contrasts the Tecolote framework with Microsoft`s OLE and Apple`s OpenDoc. An actual factorization of a traditional monolithic application into its basic components is also described.

  9. Characterization of TRIF Selectivity in the AGP Class of Lipid A Mimetics: Role of Secondary Lipid Chains

    PubMed Central

    Khalaf, Juhienah K.; Bowen, William S.; Bazin, Hélène G.; Ryter, Kendal T.; Livesay, Mark T.; Ward, Jon R.; Evans, Jay T.; Johnson, David A.

    2014-01-01

    TLR4 agonists that favor TRIF-dependent signaling and the induction of type 1 interferons may have potential as vaccine adjuvants with reduced toxicity. CRX-547 (4), a member of the aminoalkyl glucosaminide 4-phosphate (AGP) class of lipid A mimetics possessing three (R)-3-decanoyloxytetradecanoyl groups and D-relative configuration in the aglycon, selectively reduces MyD88-dependent signaling resulting in TRIF-selective signaling, whereas the corresponding secondary ether lipid 6a containing (R)-3-decyloxytetradecanoyl groups does not. In order to determine which secondary acyl groups are important for the reduction in MyD88-dependent signaling activity of 4, the six possible ester/ether hybrid derivatives of 4 and 6a were synthesized and evaluated for their ability to induce NF-κB in a HEK293 cell reporter assay. An (R)-3-decanoyloxytetradecanoyl group on the 3-position of the D-glucosamine unit was found to be indispensable for maintaining low NF-κB activity irrespective of the substitutions (decyl or decanoyl) on the other two secondary positions. These results suggest that the carbonyl group of the 3-secondary lipid chain may impede homodimerization and/or conformational changes in the TLR4–MD2 complex necessary for MyD88 binding and pro-inflammatory cytokine induction. PMID:25553892

  10. Monolithical aspherical beam expanding systems

    NASA Astrophysics Data System (ADS)

    Fuchs, U.; Matthias, Sabrina

    2014-10-01

    Beam expanding is a common task, where Galileo telescopes are preferred. However researches and customers have found limitations when using these systems. A new monolithical solution which is based on the usage of only one aspherical component will be presented. It will be shown how to combine up to five monolithical beam expanding systems and to keep the beam quality at diffraction limitation. Insights will be given how aspherical beam expanding systems will help using larger incoming beams and reducing the overall length of such a system. Additionally an add-on element for divergence and wavelength adaption will be presented.

  11. Method of monolithic module assembly

    DOEpatents

    Gee, James M.; Garrett, Stephen E.; Morgan, William P.; Worobey, Walter

    1999-01-01

    Methods for "monolithic module assembly" which translate many of the advantages of monolithic module construction of thin-film PV modules to wafered c-Si PV modules. Methods employ using back-contact solar cells positioned atop electrically conductive circuit elements affixed to a planar support so that a circuit capable of generating electric power is created. The modules are encapsulated using encapsulant materials such as EVA which are commonly used in photovoltaic module manufacture. The methods of the invention allow multiple cells to be electrically connected in a single encapsulation step rather than by sequential soldering which characterizes the currently used commercial practices.

  12. Improving permeability and chromatographic performance of poly(pentaerythritol diacrylate monostearate) monolithic column via photo-induced thiol-acrylate polymerization.

    PubMed

    Wang, Hongwei; Ou, Junjie; Bai, Jingyao; Liu, Zhongshan; Yao, Yating; Chen, Lianfang; Peng, Xiaojun; Zou, Hanfa

    2016-03-01

    A simple approach was developed for rapid preparation of polymeric monolithic columns in UV-transparent fused-silica capillaries via photoinitiated thiol-acrylate polymerization of pentaerythritol diacrylate monostearate (PEDAS) and trimethylolpropane tris(3-mercaptopropionate) (TPTM) within 10min, in which the acrylate homopolymerized and copolymerized with the thiol simultaneously. The morphology, permeability and chromatographic performance of the resulting poly(PEDAS-co-TPTM) monoliths were studied. It could be observed from SEM that the morphology of poly(PEDAS-co-TPTM) monolith was rather different from that of poly(PEDAS) monolith, which was fabricated via photo-induced free radical polymerization using PEDAS as the sole monomer. Compared with poly(PEDAS) monolith, poly(PEDAS-co-TPTM) monolith possessed better permeability when they were fabricated under the same preparation conditions. By adjusting the composition of porogenic solvents, poly(PEDAS-co-TPTM) monolith exhibited lower plate heights (15.7-17.7μm) than poly(PEDAS) monolith (19.1-37.9μm) in μLC. In addition, 66 unique peptides were positively identified on poly(PEDAS-co-TPTM) monolith when tryptic digest of four proteins was separated by μLC-MS/MS, demonstrating its potential in proteome analysis. PMID:26852266

  13. Monolithic fiber optic sensor assembly

    SciTech Connect

    Sanders, Scott

    2015-02-10

    A remote sensor element for spectrographic measurements employs a monolithic assembly of one or two fiber optics to two optical elements separated by a supporting structure to allow the flow of gases or particulates therebetween. In a preferred embodiment, the sensor element components are fused ceramic to resist high temperatures and failure from large temperature changes.

  14. Protective Skins for Aerogel Monoliths

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas; Johnston, James C.; Kuczmarski, Maria A.; Meador, Ann B.

    2007-01-01

    A method of imparting relatively hard protective outer skins to aerogel monoliths has been developed. Even more than aerogel beads, aerogel monoliths are attractive as thermal-insulation materials, but the commercial utilization of aerogel monoliths in thermal-insulation panels has been inhibited by their fragility and the consequent difficulty of handling them. Therefore, there is a need to afford sufficient protection to aerogel monoliths to facilitate handling, without compromising the attractive bulk properties (low density, high porosity, low thermal conductivity, high surface area, and low permittivity) of aerogel materials. The present method was devised to satisfy this need. The essence of the present method is to coat an aerogel monolith with an outer polymeric skin, by painting or spraying. Apparently, the reason spraying and painting were not attempted until now is that it is well known in the aerogel industry that aerogels collapse in contact with liquids. In the present method, one prevents such collapse through the proper choice of coating liquid and process conditions: In particular, one uses a viscous polymer precursor liquid and (a) carefully controls the amount of liquid applied and/or (b) causes the liquid to become cured to the desired hard polymeric layer rapidly enough that there is not sufficient time for the liquid to percolate into the aerogel bulk. The method has been demonstrated by use of isocyanates, which, upon exposure to atmospheric moisture, become cured to polyurethane/polyurea-type coats. The method has also been demonstrated by use of commercial epoxy resins. The method could also be implemented by use of a variety of other resins, including polyimide precursors (for forming high-temperature-resistant protective skins) or perfluorinated monomers (for forming coats that impart hydrophobicity and some increase in strength).

  15. Collecting peptide release from the brain using porous polymer monolith-based solid phase extraction capillaries.

    PubMed

    Iannacone, Jamie M; Ren, Shifang; Hatcher, Nathan G; Sweedler, Jonathan V

    2009-07-01

    Porous polymer monolithic (PPM) columns are employed to collect and concentrate neuronal release from invertebrate and vertebrate model systems, prior to their characterization with mass spectrometry. The monoliths are fabricated in fused-silica capillaries from lauryl methacrylate (LMA) and ethylene glycol dimethacrylate (EDMA). The binding capacities for fluorescein and for fluorescently labeled peptides are on the order of nanomoles per millimeter of length of monolith material for a capillary with an inner diameter of 200 microm. To evaluate this strategy for collecting peptides from physiological solutions, angiotensin I and insulin in artificial seawater are loaded onto, and then released from, the monoliths after a desalination rinse, resulting in femtomole limits of detection via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Positioned in the extracellular media near Aplysia californica bag cell neurons, upon electrical stimulation, these LMA-EDMA monoliths are also used to collect and concentrate peptide release, with egg-laying hormones and acidic peptide detected. In addition, the collection of several known peptides secreted from chemically stimulated mouse brain slices demonstrates their ability to collect releasates from a variety of neuronal tissues. When compared to collection approaches using individual beads placed on brain slices, the PPM capillaries offer greater binding capacity. Moreover, they maintain higher spatial resolution, compared to the larger-volume, solid-phase extraction collection strategies.

  16. Affinity monolith chromatography: A review of principles and recent analytical applications

    PubMed Central

    Pfaunmiller, Erika L.; Paulemond, Marie Laura; Dupper, Courtney M.; Hage, David S.

    2012-01-01

    Affinity monolith chromatography (AMC) is a type of liquid chromatography that uses a monolithic support and a biologically-related binding agent as a stationary phase. AMC is a powerful method for the selective separation, analysis or studies of specific target compounds in a sample. This review discusses the basic principles of AMC and recent developments or applications of this method, with particular emphasis being given to work that has appeared in the last five years. Various materials that have been used to prepare columns for AMC are examined, including organic monoliths, silica monoliths, agarose monoliths and cryogels. These supports have been used in AMC for formats that have ranged from traditional columns to disks, microcolumns and capillaries. Many binding agents have also been employed in AMC, such as antibodies, enzymes, proteins, lectins, immobilized metal-ions and dyes. Some applications that have been reported with these binding agents in AMC are bioaffinity chromatography, immunoaffinity chromatography or immunoextraction, immobilized metal-ion affinity chromatography, dye-ligand affinity chromatography, chiral separations and biointeraction studies. Examples are presented from fields that include analytical chemistry, pharmaceutical analysis, clinical testing and biotechnology. Current trends and possible future directions in AMC are also discussed. PMID:23187827

  17. Polymer monolith microextraction using poly(butyl methacrylate-co-1,6-hexanediol ethoxylate diacrylate) monolithic sorbent for determination of phenylurea herbicides in water samples.

    PubMed

    Lin, Shu-Ling; Wu, Yu-Ru; Fuh, Ming-Ren

    2016-01-15

    In this study, recently developed 1,6-hexanediol ethoxylate diacrylate (HEDA)-based polymeric monoliths were utilized as sorbents for efficient extraction of phenylurea herbicides (PUHs) from water samples. The HEDA-based monolithic sorbents were prepared in a fused silica capillary (0.7mm i.d., 4.5-cm long) for polymer monolith microextraction (PMME). The experimental parameters of PMME microextraction including sample loading speed, pH of sample solution, composition of elution solvent, and addition of salt were optimized to efficiently extract PUHs from environmental water samples. The extracted PUHs were determined using ultra-high performance liquid chromatography (UHPLC) with UV-photodiode array detection. The extraction recoveries for PUHs-spiked water samples were 91.1-108.1% with relative standard deviations lower than 5%. The linearity range was 0.025-25ngmL(-1) for each PUH and the detection limits of PUHs were estimated at 0.006-0.019ng mL(-1). In addition, good intra-day/inter-day precision (0.1-8.7%/0.2-8.9%) and accuracy (92.0-108.0%/96.5-105.2%) of the proposed method were obtained. The extraction capacity of the monolith-filled capillary was also determined to be approximately 1μg. Moreover, each monolith-filled capillary could be reused up to 8 times without carry-over. According to the European Union regulations, the allowed permissible limit of any single herbicide in drinking water is 0.1ng mL(-1). This permissible level fell in the linear range examined in this study. In addition, the proposed method provided detection limits lower than the allowed permissible level, which demonstrated the feasibility of utilizing the HEDA-based monolithic sorbent to perform PMME for determining contaminants, such as PUHs, in environmental application.

  18. Advances in the development of organic polymer monolithic columns and their applications in food analysis--a review.

    PubMed

    Jandera, Pavel

    2013-10-25

    Monolithic continuous separation media are gradually finding their way to sample pre-treatment, isolation, enrichment and final analytical separations of a plethora of compounds, occurring as food components, additives or contaminants, including pharmaceuticals, pesticides and toxins, which have traditionally been the domain of particulate chromatographic materials. In the present review, recent advances in the technology of monolithic columns and the applications in food analysis are addressed. Silica-based monoliths are excellent substitutes to conventional particle-packed columns, improving the speed of analysis for low-molecular weight compounds, due to their excellent efficiency and high permeability. These properties have been recently appreciated in two-dimensional HPLC, where the performance in the second dimension is of crucial importance. Organic-polymer monoliths in various formats provide excellent separations of biopolymers. Thin monolithic disks or rod columns are widely employed in isolation, purification and pre-treatment of sample containing proteins, peptides or nucleic acid fragments. Monolithic capillaries were originally intended for use in electrochromatography, but are becoming more frequently used for capillary and micro-HPLC. Monoliths are ideal highly porous support media for immobilization or imprinting template molecules, to provide sorbents for shape-selective isolation of target molecules from various matrices occurring in food analysis. The separation efficiency of organic polymer monoliths for small molecules can be significantly improved by optimization of polymerization approach, or by post-polymerization modification. This will enable full utilization of a large variety of available monomers to prepare monoliths with chemistry matching the needs of selectivity of separations of various food samples containing even very polar or ionized compounds.

  19. Silica reusable surface insulation

    NASA Technical Reports Server (NTRS)

    Goldstein, H. E.; Smith, M.; Leiser, D. B. (Inventor)

    1976-01-01

    A reusable silica surface insulation material is provided by bonding amorphous silica fibers with colloidal silica at an elevated temperature. The surface insulation is ordinarily manufactured in the form of blocks (i.e., tiles).

  20. Monolithic-integrated microlaser encoder.

    PubMed

    Sawada, R; Higurashi, E; Ito, T; Ohguchi, O; Tsubamoto, M

    1999-11-20

    We have developed an extremely small integrated microencoder whose sides are less than 1 mm long. It is 1/100 the size of conventional encoders. This microencoder consists of a laser diode, monolithic photodiodes, and fluorinated polyimide waveguides with total internal reflection mirrors. The instrument can measure the relative displacement between a grating scale and the encoder with a resolution of the order of 0.01 microm; it can also determine the direction in which the scale is moving. By using the two beams that were emitted from the two etched mirrors of the laser diode, by monolithic integration of the waveguide and photodiodes, and by fabrication of a step at the edge of the waveguide, we were able to eliminate conventional bulky optical components such as the beam splitter, the quarter-wavelength plate, bulky mirrors, and bulky photodetectors. PMID:18324228

  1. Monolithic pattern-sensitive detector

    DOEpatents

    Berger, Kurt W.

    2000-01-01

    Extreme ultraviolet light (EUV) is detected using a precisely defined reference pattern formed over a shallow junction photodiode. The reference pattern is formed in an EUV absorber preferably comprising nickel or other material having EUV- and other spectral region attenuating characteristics. An EUV-transmissive energy filter is disposed between a passivation oxide layer of the photodiode and the EUV transmissive energy filter. The device is monolithically formed to provide robustness and compactness.

  2. Carbon nanomaterials in silica aerogel matrices

    SciTech Connect

    Hamilton, Christopher E; Chavez, Manuel E; Duque, Juan G; Gupta, Gautam; Doorn, Stephen K; Dattelbaum, Andrew M; Obrey, Kimberly A D

    2010-01-01

    Silica aerogels are ultra low-density, high surface area materials that are extremely good thermal insulators and have numerous technical applications. However, their mechanical properties are not ideal, as they are brittle and prone to shattering. Conversely, single-walled carbon nanotubes (SWCNTs) and graphene-based materials, such as graphene oxide, have extremely high tensile strength and possess novel electronic properties. By introducing SWCNTs or graphene-based materials into aerogel matrices, it is possible to produce composites with the desirable properties of both constituents. We have successfully dispersed SWCNTs and graphene-based materials into silica gels. Subsequent supercritical drying results in monolithic low-density composites having improved mechanical properties. These nanocomposite aerogels have great potential for use in a wide range of applications.

  3. Characterization of polyacrylamide based monolithic columns.

    PubMed

    Plieva, Fatima M; Andersson, Jonatan; Galaev, Igor Yu; Mattiasson, Bo

    2004-07-01

    Supermacroporous monolithic polyacrylamide (pAAm)-based columns have been prepared by radical cryo-copolymerization (copolymerization in the moderately frozen system) of acrylamide with functional co-monomer, allyl glycidyl ether (AGE), and cross-linker N,N'-methylene-bis-acrylamide (MBAAm) directly in glass columns (ID 10 mm). The monolithic columns have uniform supermacroporous sponge-like structure with interconnected supermacropores of pore size 5-100 microm. The monoliths can be dried and stored in the dry state. High mechanical stability of the monoliths allowed sterilization by autoclaving. Column-to-column reproducibility of pAAm-monoliths was demonstrated on 5 monolithic columns from different batches prepared under the same cryostructuration conditions.

  4. Characterization of polyacrylamide based monolithic columns.

    PubMed

    Plieva, Fatima M; Andersson, Jonatan; Galaev, Igor Yu; Mattiasson, Bo

    2004-07-01

    Supermacroporous monolithic polyacrylamide (pAAm)-based columns have been prepared by radical cryo-copolymerization (copolymerization in the moderately frozen system) of acrylamide with functional co-monomer, allyl glycidyl ether (AGE), and cross-linker N,N'-methylene-bis-acrylamide (MBAAm) directly in glass columns (ID 10 mm). The monolithic columns have uniform supermacroporous sponge-like structure with interconnected supermacropores of pore size 5-100 microm. The monoliths can be dried and stored in the dry state. High mechanical stability of the monoliths allowed sterilization by autoclaving. Column-to-column reproducibility of pAAm-monoliths was demonstrated on 5 monolithic columns from different batches prepared under the same cryostructuration conditions. PMID:15354560

  5. Monolithic optofluidic ring resonator lasers created by femtosecond laser nanofabrication.

    PubMed

    Chandrahalim, Hengky; Chen, Qiushu; Said, Ali A; Dugan, Mark; Fan, Xudong

    2015-05-21

    We designed, fabricated, and characterized a monolithically integrated optofluidic ring resonator laser that is mechanically, thermally, and chemically robust. The entire device, including the ring resonator channel and sample delivery microfluidics, was created in a block of fused-silica glass using a 3-dimensional femtosecond laser writing process. The gain medium, composed of Rhodamine 6G (R6G) dissolved in quinoline, was flowed through the ring resonator. Lasing was achieved at a pump threshold of approximately 15 μJ mm(-2). Detailed analysis shows that the Q-factor of the optofluidic ring resonator is 3.3 × 10(4), which is limited by both solvent absorption and scattering loss. In particular, a Q-factor resulting from the scattering loss can be as high as 4.2 × 10(4), suggesting the feasibility of using a femtosecond laser to create high quality optical cavities.

  6. Monolithic molecularly imprinted polymeric capillary columns for isolation of aflatoxins.

    PubMed

    Szumski, Michał; Grzywiński, Damian; Prus, Wojciech; Buszewski, Bogusław

    2014-10-17

    Monolithic molecularly imprinted polymers extraction columns have been prepared in fused-silica capillaries by UV or thermal polymerization in a two-step process. First, a poly-(trimethylolpropane trimethacrylate) (polyTRIM) core monolith was synthesized either by UV or thermal polymerization. Then it was grafted with the mixture of methacrylic acid (MAA) as a functional monomer, ethylene dimethacrylate (EDMA) as a cross-linking agent, 5,7-dimethoxycoumarin (DMC) as an aflatoxin-mimicking template, toluene as a porogen solvent and 2,2-azobis-(2-methylpropionitrile) (AIBN) as an initiator of the polymerization reaction. Different thermal condition of the photografting and different concentrations of the grafting mixture were tested during polymerization. The extraction capillary columns were evaluated in the terms of their hydrodynamic and chromatographic properties. Retention coefficients for aflatoxin B1 and DMC were used for assessment of the selectivity and imprinting factor. The obtained results indicate that the temperature of photografting and concentration of the grafting mixture are key parameters that determine the quality of the prepared MIPs. From the MIP columns characterized by the highest permeability the column of the highest imprinting factor was applied for isolation of aflatoxins B1, B2, G1 and G2 from the model aqueous sample followed by on-line chromatographic separation. The process was performed using a micro-MISPE-microLC-LIF system of a novel design, which allowed for detection of the eluates from the sample preparation part as well as from the chromatographic separation.

  7. Spectroscopic Investigation on the Primary Photoreaction of Bathy Phytochrome Agp2-Pr of Agrobacterium fabrum: Isomerization in a pH-dependent H-bond Network.

    PubMed

    Singer, Patrick; Wörner, Sybille; Lamparter, Tilman; Diller, Rolf

    2016-05-01

    Bathy phytochrome Agp2 from Agrobacterium fabrum exhibits an unusually low pKa =7.6 in the Pr state in contrast to a pKa >11 in the Pfr state, indicating a pH-dependent charge distribution and H-bond network in the Pr chromophore binding pocket around neutral pH. Here, we report on ultrafast UV/Vis absorption spectroscopy of the primary Pr photoisomerization of Agp2 at pH 6 and pH 9 and upon H2 O/D2 O buffer exchange. The triexponential Pr kinetics slows down at increased pH and pronounced pH-dependent kinetic isotope effects are observed. The results on the Pr photoreaction suggest: 1) component-wise hindered dynamics on the chromophore excited-state potential energy surface at high pH and 2) proton translocation processes either via single-proton transfer or via significant reorganization of H-bond networks. Both effects reflect the interplay between the pH-dependent charge distribution in the Pr chromophore binding pocket on the one hand and chromophore excitation and its Z→E isomerization on the other hand. PMID:27075723

  8. Compact monolithic capacitive discharge unit

    DOEpatents

    Roesler, Alexander W.; Vernon, George E.; Hoke, Darren A.; De Marquis, Virginia K.; Harris, Steven M.

    2007-06-26

    A compact monolithic capacitive discharge unit (CDU) is disclosed in which a thyristor switch and a flyback charging circuit are both sandwiched about a ceramic energy storage capacitor. The result is a compact rugged assembly which provides a low-inductance current discharge path. The flyback charging circuit preferably includes a low-temperature co-fired ceramic transformer. The CDU can further include one or more ceramic substrates for enclosing the thyristor switch and for holding various passive components used in the flyback charging circuit. A load such as a detonator can also be attached directly to the CDU.

  9. Improved monolithic tandem solar cell

    SciTech Connect

    Wanlass, M.W.

    1991-04-23

    A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surf ace of the InP substrate, (c) a second photoactive subcell on the first subcell; and (d) an optically transparent prismatic cover layer over the second subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched.

  10. Nanosecond monolithic CMOS readout cell

    DOEpatents

    Souchkov, Vitali V.

    2004-08-24

    A pulse shaper is implemented in monolithic CMOS with a delay unit formed of a unity gain buffer. The shaper is formed of a difference amplifier having one input connected directly to an input signal and a second input connected to a delayed input signal through the buffer. An elementary cell is based on the pulse shaper and a timing circuit which gates the output of an integrator connected to the pulse shaper output. A detector readout system is formed of a plurality of elementary cells, each connected to a pixel of a pixel array, or to a microstrip of a plurality of microstrips, or to a detector segment.

  11. Monolithic 20-GHz Transmitting Module

    NASA Technical Reports Server (NTRS)

    Kascak, T.; Kaelin, G.; Gupta, A.

    1986-01-01

    20-GHz monolithic microwave/millimeter-wave integrated circuit (MMIC) with amplification and phase-shift (time-delay) capabilities developed. Use of MMIC module technology promises to make feasible development of weight- and cost-effective phased-array antenna systems, identified as major factor in achieving minimum cost and efficient use of frequency and orbital resources of future generations of communication satellite systems. Use of MMIC transmitting modules provides for relatively simple method for phase-shift control of many separate radio-frequency (RF) signals required for phased-array antenna systems.

  12. Monolithically integrated absolute frequency comb laser system

    DOEpatents

    Wanke, Michael C.

    2016-07-12

    Rather than down-convert optical frequencies, a QCL laser system directly generates a THz frequency comb in a compact monolithically integrated chip that can be locked to an absolute frequency without the need of a frequency-comb synthesizer. The monolithic, absolute frequency comb can provide a THz frequency reference and tool for high-resolution broad band spectroscopy.

  13. The Functional Property Changes of Muscular Na(v)1.4 and Cardiac Na(v)1.5 Induced by Scorpion Toxin BmK AGP-SYPU1 Mutants Y42F and Y5F.

    PubMed

    Meng, Xiangxue; Xu, Yijia; Zhao, Mingyi; Wang, Fangyang; Ma, Yuanyuan; Jin, Yao; Liu, Yanfeng; Song, Yongbo; Zhang, Jinghai

    2015-05-19

    Scorpion toxins are invaluable therapeutic leads and pharmacological tools which influence the voltage-gated sodium channels. However, the details were still unclear about the structure-function relationship of scorpion toxins on VGSC subtypes. In the previous study, we reported one α-type scorpion toxin Bmk AGP-SYPU1 and its two mutants (Y5F and Y42F) which had been demonstrated to ease pain in mice acetic acid writhing test. However, the function of Bmk AGP-SYPU1 on VGSCs is still unknown. In this study, we examined the effects of BmK AGP-SYPU1 and its two mutants (Y5F and Y42F) on hNa(v)1.4 and hNa(v)1.5 heterologously expressed CHO cell lines by using Na⁺-specialized fluorescent dye and whole-cell patch clamp. The data showed that BmK AGP-SYPU1 displayed as an activator of hNa(v)1.4 and hNa(v)1.5, which might indeed contribute to its biotoxicity to muscular and cardiac system and exhibited the functional properties of both the α-type and β-type scorpion toxin. Notably, Y5F mutant exhibited lower activatory effects on hNa(v)1.4 and hNa(v)1.5 compared with BmK AGP-SYPU1. Y42F was an enhanced activator and confirmed that the conserved Tyr42 was the key amino acid involved in bioactivity or biotoxicity. These data provided a deep insight into the structure-function relationship of BmK AGP-SYPU1, which may be the guidance for engineering α-toxin with high selectivity on VGSC subtypes. PMID:25919575

  14. Adsorption over polyacrylonitrile based carbon monoliths

    NASA Astrophysics Data System (ADS)

    Nandi, Mahasweta; Dutta, Arghya; Patra, Astam Kumar; Bhaumik, Asim; Uyama, Hiroshi

    2013-02-01

    Highly porous activated carbon monoliths have been prepared from mesoporous polyacrylonitrile (PAN) monolith as the carbon precursor. The mesoporous PAN monoliths are fabricated by a unique and facile template-free method which on carbonization gives N-doped activated carbon monoliths. The carbonization is achieved via two step thermal process which includes pretreatment in air leading to cyclization and subsequent aromatization of the PAN moieties followed by carbonization in a mixture of argon and carbon dioxide to give a layered carbon framework. Nitrogen sorption experiments carried over these carbon monoliths revealed high surface area (ca. 2500 m2g-1) for these materials with precise micropore size distribution. The activated carbons show extraordinarily high CO2 capture capacity and the uptake up to 3 bar has been found to be as high as 22.5 and 10.6 mmol/g at 273 K and 298 K, respectively.

  15. Preparation of a thermoresponsive polymer grafted polystyrene monolithic capillary for the separation of bioactive compounds.

    PubMed

    Koriyama, Takuya; Asoh, Taka-Aki; Kikuchi, Akihiko

    2016-11-01

    To develop aqueous microseparation columns for bioactive compounds, a thermoresponsive polymer grafted polymer monolith was prepared inside silica capillaries having an I.D. of 100μm by polymerization of styrene (St) with m/p-divinylbenzene (DVB) in the presence of polydimethylsiloxane as porogen, followed by surface-initiated atom transfer radical polymerization (SI-ATRP) of N-isopropylacrylamide (NIPAAm). SEM analysis indicated that the resulting poly(N-isopropylacrylamide) (PNIPAAm) grafted polystyrene monolith had a consecutive three-dimensionally interconnected structure and through-pores, similar to the base polystyrene (PSt) monolith. The elution behavior of steroids with different hydrophobicity was evaluated using micro-high-performance liquid chromatography in sole aqueous mobile phase. Temperature dependent interaction changes were observed between steroids and the PNIPAAm modified surfaces. Furthermore, the interaction between bioactive compounds and the PNIPAAm grafted PSt surfaces was controlled and eventually separate these molecules with different hydrophobicities by simple temperature modulation in aqueous environment. The PNIPAAm grafted PSt monolithic capillary showed improved separation properties of bioactive compounds, compared with a PNIPAAm grafted hollow capillary in aqueous environment. PMID:27559999

  16. Preparation of a thermoresponsive polymer grafted polystyrene monolithic capillary for the separation of bioactive compounds.

    PubMed

    Koriyama, Takuya; Asoh, Taka-Aki; Kikuchi, Akihiko

    2016-11-01

    To develop aqueous microseparation columns for bioactive compounds, a thermoresponsive polymer grafted polymer monolith was prepared inside silica capillaries having an I.D. of 100μm by polymerization of styrene (St) with m/p-divinylbenzene (DVB) in the presence of polydimethylsiloxane as porogen, followed by surface-initiated atom transfer radical polymerization (SI-ATRP) of N-isopropylacrylamide (NIPAAm). SEM analysis indicated that the resulting poly(N-isopropylacrylamide) (PNIPAAm) grafted polystyrene monolith had a consecutive three-dimensionally interconnected structure and through-pores, similar to the base polystyrene (PSt) monolith. The elution behavior of steroids with different hydrophobicity was evaluated using micro-high-performance liquid chromatography in sole aqueous mobile phase. Temperature dependent interaction changes were observed between steroids and the PNIPAAm modified surfaces. Furthermore, the interaction between bioactive compounds and the PNIPAAm grafted PSt surfaces was controlled and eventually separate these molecules with different hydrophobicities by simple temperature modulation in aqueous environment. The PNIPAAm grafted PSt monolithic capillary showed improved separation properties of bioactive compounds, compared with a PNIPAAm grafted hollow capillary in aqueous environment.

  17. Mesoporous monoliths of inverse bicontinuous cubic phases of block copolymer bilayers

    NASA Astrophysics Data System (ADS)

    Park, Chiyoung; La, Yunju; An, Tae Hyun; Jeong, Hu Young; Kang, Sebyung; Joo, Sang Hoon; Ahn, Hyungju; Shin, Tae Joo; Kim, Kyoung Taek

    2015-03-01

    Solution self-assembly of block copolymers into inverse bicontinuous cubic mesophases is a promising new approach for creating porous polymer films and monoliths with highly organized bicontinuous mesoporous networks. Here we report the direct self-assembly of block copolymers with branched hydrophilic blocks into large monoliths consisting of the inverse bicontinuous cubic structures of the block copolymer bilayer. We suggest a facile and scalable method of solution self-assembly by diffusion of water to the block copolymer solution, which results in the unperturbed formation of mesoporous monoliths with large-pore (>25 nm diameter) networks weaved in crystalline lattices. The surface functional groups of the internal large-pore networks are freely accessible for large guest molecules such as protein complexes of which the molecular weight exceeded 100 kDa. The internal double-diamond (Pn3m) networks of large pores within the mesoporous monoliths could be replicated to self-supporting three-dimensional skeletal structures of crystalline titania and mesoporous silica.

  18. A new anion-exchange/hydrophobic monolith as stationary phase for nano liquid chromatography of small organic molecules and inorganic anions.

    PubMed

    Aydoğan, Cemil

    2015-05-01

    In this study, an anion-exchange/hydrophobic polymethacrylate-based stationary phase was prepared for nano-liquid chromatography of small organic molecules and inorganic anions. The stationary phase was synthesized by in situ polymerization of 3-chloro-2-hydroxypropylmethacrylate and ethylene dimethacrylate inside silanized 100 μm i.d. fused silica capillary. The porogen mixture consisted of toluene and dodecanol. The pore size distrubution profiles of the resulting monolith were determined by mercury intrusion porosimetry and the morphology of the prepared monolith was investigated by scanning electron microscope. Good permeability, stability and column efficiency were observed on the monolithic column with nano flow. The produced monolithic column, which contains reactive chloro groups, was then modified by reaction with N,N-dimethyl-N-dodecylamine to obtain an anion-exchange/hydrophobic monolithic stationary phase. The functionalized monolith contained ionizable amine groups and hydrophobic groups that are useful of anion-exchange/hydrophobic mixed-mode chromatography. The final monolithic column performance with respect to anion-exchange and hydrophobic interactions was assesed by the separation of alkylbenzene derivatives, phenolic compounds and inorganic anions, respectively. Theoretical plate numbers up to 23,000 plates/m were successfully achieved in the separation of inorganic anions.

  19. Chromatographic selectivity of poly(alkyl methacrylate-co-divinylbenzene) monolithic columns for polar aromatic compounds by pressure-driven capillary liquid chromatography.

    PubMed

    Lin, Shu-Ling; Wang, Chih-Chieh; Fuh, Ming-Ren

    2016-10-01

    In this study, divinylbenzene (DVB) was used as the cross-linker to prepare alkyl methacrylate (AlMA) monoliths for incorporating π-π interactions between the aromatic analytes and AlMA-DVB monolithic stationary phases in capillary LC analysis. Various AlMA/DVB ratios were investigated to prepare a series of 30% AlMA-DVB monolithic stationary phases in fused-silica capillaries (250-μm i.d.). The physical properties (such as porosity, permeability, and column efficiency) of the synthesized AlMA-DVB monolithic columns were investigated for characterization. Isocratic elution of phenol derivatives was first employed to evaluate the suitability of the prepared AlMA-DVB columns for small molecule separation. The run-to-run (0.16-1.20%, RSD; n = 3) and column-to-column (0.26-2.95%, RSD; n = 3) repeatabilities on retention times were also examined using the selected AlMA-DVB monolithic columns. The π-π interactions between the aromatic ring and the DVB-based stationary phase offered better recognition on polar analytes with aromatic moieties, which resulted in better separation resolution of aromatic analytes on the AlMA-DVB monolithic columns. In order to demonstrate the capability of potential environmental and/or food safety applications, eight phenylurea herbicides with single benzene ring and seven sulfonamide antibiotics with polyaromatic moieties were analyzed using the selected AlMA-DVB monolithic columns.

  20. Chromatographic selectivity of poly(alkyl methacrylate-co-divinylbenzene) monolithic columns for polar aromatic compounds by pressure-driven capillary liquid chromatography.

    PubMed

    Lin, Shu-Ling; Wang, Chih-Chieh; Fuh, Ming-Ren

    2016-10-01

    In this study, divinylbenzene (DVB) was used as the cross-linker to prepare alkyl methacrylate (AlMA) monoliths for incorporating π-π interactions between the aromatic analytes and AlMA-DVB monolithic stationary phases in capillary LC analysis. Various AlMA/DVB ratios were investigated to prepare a series of 30% AlMA-DVB monolithic stationary phases in fused-silica capillaries (250-μm i.d.). The physical properties (such as porosity, permeability, and column efficiency) of the synthesized AlMA-DVB monolithic columns were investigated for characterization. Isocratic elution of phenol derivatives was first employed to evaluate the suitability of the prepared AlMA-DVB columns for small molecule separation. The run-to-run (0.16-1.20%, RSD; n = 3) and column-to-column (0.26-2.95%, RSD; n = 3) repeatabilities on retention times were also examined using the selected AlMA-DVB monolithic columns. The π-π interactions between the aromatic ring and the DVB-based stationary phase offered better recognition on polar analytes with aromatic moieties, which resulted in better separation resolution of aromatic analytes on the AlMA-DVB monolithic columns. In order to demonstrate the capability of potential environmental and/or food safety applications, eight phenylurea herbicides with single benzene ring and seven sulfonamide antibiotics with polyaromatic moieties were analyzed using the selected AlMA-DVB monolithic columns. PMID:27639150

  1. Microfluidic devices and methods including porous polymer monoliths

    DOEpatents

    Hatch, Anson V; Sommer, Gregory J; Singh, Anup K; Wang, Ying-Chih; Abhyankar, Vinay V

    2014-04-22

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  2. Microfluidic devices and methods including porous polymer monoliths

    SciTech Connect

    Hatch, Anson V.; Sommer, Gregory j.; Singh, Anup K.; Wang, Ying-Chih; Abhyankar, Vinay

    2015-12-01

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  3. Accelerated colorimetric immunosensing using surface-modified porous monoliths and gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Chuag, Shao-Hsuan; Chen, Guan-Hua; Chou, Hsin-Hao; Shen, Shu-Wei; Chen, Chien-Fu

    2013-08-01

    A rapid and sensitive immunoassay platform integrating polymerized monoliths and gold nanoparticles (AuNPs) has been developed. The porous monoliths are photopolymerized in situ within a silica capillary and serve as solid support for high-mass transport and high-density capture antibody immobilization to create a shorter diffusion length for antibody-antigen interactions, resulting in a rapid assay and low reagent consumption. AuNPs are modified with detection antibodies and are utilized as signals for colorimetric immunoassays without the need for enzyme, substrate and sophisticated equipment for quantitative measurements. This platform has been verified by performing a human IgG sandwich immunoassay with a detection limit of 0.1 ng ml-1. In addition, a single assay can be completed in 1 h, which is more efficient than traditional immunoassays that require several hours to complete.

  4. Monolithic solid electrolyte oxygen pump

    DOEpatents

    Fee, Darrell C.; Poeppel, Roger B.; Easler, Timothy E.; Dees, Dennis W.

    1989-01-01

    A multi-layer oxygen pump having a one-piece, monolithic ceramic structure affords high oxygen production per unit weight and volume and is thus particularly adapted for use as a portable oxygen supply. The oxygen pump is comprised of a large number of small cells on the order of 1-2 millimeters in diameter which form the walls of the pump and which are comprised of thin, i.e., 25-50 micrometers, ceramic layers of cell components. The cell components include an air electrode, an oxygen electrode, an electrolyte and interconnection materials. The cell walls form the passages for input air and for exhausting the oxygen which is transferred from a relatively dilute gaseous mixture to a higher concentration by applying a DC voltage across the electrodes so as to ionize the oxygen at the air electrode, whereupon the ionized oxygen travels through the electrolyte and is converted to oxygen gas at the oxygen electrode.

  5. Monolithic Continuous-Flow Bioreactors

    NASA Technical Reports Server (NTRS)

    Stephanopoulos, Gregory; Kornfield, Julia A.; Voecks, Gerald A.

    1993-01-01

    Monolithic ceramic matrices containing many small flow passages useful as continuous-flow bioreactors. Ceramic matrix containing passages made by extruding and firing suitable ceramic. Pores in matrix provide attachment medium for film of cells and allow free movement of solution. Material one not toxic to micro-organisms grown in reactor. In reactor, liquid nutrients flow over, and liquid reaction products flow from, cell culture immobilized in one set of channels while oxygen flows to, and gaseous reaction products flow from, culture in adjacent set of passages. Cells live on inner surfaces containing flowing nutrient and in pores of walls of passages. Ready access to nutrients and oxygen in channels. They generate continuous high yield characteristic of immobilized cells, without large expenditure of energy otherwise incurred if necessary to pump nutrient solution through dense biomass as in bioreactors of other types.

  6. [Preparation of a strong cation-exchange polymer monolith and its application in determination of melamine in milk products].

    PubMed

    Ma, Qiao; Hu, Xizhou; Huang, Jincui; Feng, Yuqi

    2009-09-01

    A poly (2-acrylamido-2-methyl-1-propanesulfonic acid-co-ethylene dimethacrylate) (AMPS-co-EDMA) monolith was prepared in a fused-silica capillary (530 microm i.d.) and applied for polymer monolith microextraction (PMME). With the optimal ratio of N, N-dimethyl-formamide (DMF, porogen) and polyethylene glycol (PEG, co-porogen), the resulting monolith exhibited satisfactory permeability, high mechanical strength and good stability in aqueous buffer. The effects of several parameters to PMME were investigated, such as pH value, inorganic salt and organic phase concentration of the sample matrix. It demonstrated that the melamine was captured on the poly (AMPS-co-EDMA) monolith mainly through strong cation-exchange and hydrophobic interactions. A novel approach is presented for the determination of melamine in milk products by coupling PMME to high performance liquid chromatography with ultraviolet detection. Because of the high extraction capacity of the monolith towards melamine, low detection limits (S/N = 3, 0.9 mg/kg) and quantification limits (S/N = 10, 0.3 mg/kg) were obtained. The method showed good linearity ranging from 0.5 to 80 mg/kg. Excellent reproducibility of the method was exhibited by intraday and interday precisions, yielding the relative standard deviations not larger than 7.5%. The proposed method is simple, rapid, sensitive, and low cost.

  7. Multifunctional mesoporous silica catalyst

    DOEpatents

    Lin, Victor Shang-Yi; Tsai, Chih-Hsiang; Chen, Hung-Ting; Pruski, Marek; Kobayashi, Takeshi

    2015-03-31

    The present invention provides bifunctional silica mesoporous materials, including mesoporous silica nanoparticles ("MSN"), having pores modified with diarylammonium triflate and perfluoroaryl moieties, that are useful for the acid-catalyzed esterification of organic acids with organic alcohols.

  8. What Is Crystalline Silica?

    MedlinePlus

    ... silica, and requires a repirator protection program until engineering controls are implemented. Additionally, OSHA has a National ... silica materials with safer substitutes, whenever possible. ■ Provide engineering or administrative controls, where feasible, such as local ...

  9. The Crystal Structures of the N-terminal Photosensory Core Module of Agrobacterium Phytochrome Agp1 as Parallel and Anti-parallel Dimers.

    PubMed

    Nagano, Soshichiro; Scheerer, Patrick; Zubow, Kristina; Michael, Norbert; Inomata, Katsuhiko; Lamparter, Tilman; Krauß, Norbert

    2016-09-23

    Agp1 is a canonical biliverdin-binding bacteriophytochrome from the soil bacterium Agrobacterium fabrum that acts as a light-regulated histidine kinase. Crystal structures of the photosensory core modules (PCMs) of homologous phytochromes have provided a consistent picture of the structural changes that these proteins undergo during photoconversion between the parent red light-absorbing state (Pr) and the far-red light-absorbing state (Pfr). These changes include secondary structure rearrangements in the so-called tongue of the phytochrome-specific (PHY) domain and structural rearrangements within the long α-helix that connects the cGMP-specific phosphodiesterase, adenylyl cyclase, and FhlA (GAF) and the PHY domains. We present the crystal structures of the PCM of Agp1 at 2.70 Å resolution and of a surface-engineered mutant of this PCM at 1.85 Å resolution in the dark-adapted Pr states. Whereas in the mutant structure the dimer subunits are in anti-parallel orientation, the wild-type structure contains parallel subunits. The relative orientations between the PAS-GAF bidomain and the PHY domain are different in the two structures, due to movement involving two hinge regions in the GAF-PHY connecting α-helix and the tongue, indicating pronounced structural flexibility that may give rise to a dynamic Pr state. The resolution of the mutant structure enabled us to detect a sterically strained conformation of the chromophore at ring A that we attribute to the tight interaction with Pro-461 of the conserved PRXSF motif in the tongue. Based on this observation and on data from mutants where residues in the tongue region were replaced by alanine, we discuss the crucial roles of those residues in Pr-to-Pfr photoconversion. PMID:27466363

  10. Anisotropically structured magnetic aerogel monoliths

    NASA Astrophysics Data System (ADS)

    Heiligtag, Florian J.; Airaghi Leccardi, Marta J. I.; Erdem, Derya; Süess, Martin J.; Niederberger, Markus

    2014-10-01

    Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture.Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture. Electronic supplementary information (ESI) available: Digital photographs of dispersions and gels with different water-to-ethanol ratios; magnetic measurements of an anatase aerogel containing 0.25 mol% Fe3O4 nanoparticles; XRD patterns of the iron oxide and

  11. Monolithic cells for solar fuels.

    PubMed

    Rongé, Jan; Bosserez, Tom; Martel, David; Nervi, Carlo; Boarino, Luca; Taulelle, Francis; Decher, Gero; Bordiga, Silvia; Martens, Johan A

    2014-12-01

    Hybrid energy generation models based on a variety of alternative energy supply technologies are considered the best way to cope with the depletion of fossil energy resources and to limit global warming. One of the currently missing technologies is the mimic of natural photosynthesis to convert carbon dioxide and water into chemical fuel using sunlight. This idea has been around for decades, but artificial photosynthesis of organic molecules is still far away from providing real-world solutions. The scientific challenge is to perform in an efficient way the multi-electron transfer reactions of water oxidation and carbon dioxide reduction using holes and single electrons generated in an illuminated semiconductor. In this tutorial review the design of photoelectrochemical (PEC) cells that combine solar water oxidation and CO2 reduction is discussed. In such PEC cells simultaneous transport and efficient use of light, electrons, protons and molecules has to be managed. It is explained how efficiency can be gained by compartmentalisation of the water oxidation and CO2 reduction processes by proton exchange membranes, and monolithic concepts of artificial leaves and solar membranes are presented. Besides transferring protons from the anode to the cathode compartment the membrane serves as a molecular barrier material to prevent cross-over of oxygen and fuel molecules. Innovative nano-organized multimaterials will be needed to realise practical artificial photosynthesis devices. This review provides an overview of synthesis techniques which could be used to realise monolithic multifunctional membrane-electrode assemblies, such as Layer-by-Layer (LbL) deposition, Atomic Layer Deposition (ALD), and porous silicon (porSi) engineering. Advances in modelling approaches, electrochemical techniques and in situ spectroscopies to characterise overall PEC cell performance are discussed.

  12. Silica extraction from geothermal water

    DOEpatents

    Bourcier, William L; Bruton, Carol J

    2014-09-23

    A method of producing silica from geothermal fluid containing low concentration of the silica of less than 275 ppm includes the steps of treating the geothermal fluid containing the silica by reverse osmosis treatment thereby producing a concentrated fluid containing the silica, seasoning the concentrated fluid thereby producing a slurry having precipitated colloids containing the silica, and separating the silica from the slurry.

  13. Amine Gradient Stationary Phases on In-House Built Monolithic Columns for Liquid Chromatography.

    PubMed

    Dewoolkar, Veeren C; Jeong, Lena N; Cook, Daniel W; Ashraf, Kayesh M; Rutan, Sarah C; Collinson, Maryanne M

    2016-06-01

    Stationary phase gradients on monolithic silica columns have been successfully and reproducibly prepared and characterized with comparisons made to uniformly modified stationary phases. Stationary phase gradients hold great potential for use in liquid chromatography (LC), both in terms of simplifying analysis as well as providing novel selectivity. In this work, we demonstrate the creation of a continuous stationary phase gradient on in-house synthesized monolithic columns by infusing an aminoalkoxysilane solution through the silica monoliths via controlled rate infusion. The presence of amine and its distribution along the length of gradient and uniformly modified columns were assessed via X-ray photoelectron spectroscopy (XPS). XPS showed a clear gradient in surface coverage along the length of the column for the gradient stationary phases while a near uniform distribution on the uniformly modified stationary phases. To demonstrate the application of these gradient stationary phases, the separations of both nucleobases and weak acids/weak bases on these gradient stationary phases have been compared to uniformly modified and unmodified silica columns. Of particular note, the retention characteristics of 11 gradient columns, 5 uniformly modified columns, and 5 unmodified columns have been tested to establish the reproducibility of the synthetic procedures. Standard deviations of the retention factors were in the range from 0.06 to 0.5, depending on the analyte species. We show that selectivity is achieved with the stationary phase gradients that are significantly different from either uniformly modified amine or unmodified columns. These results indicate the significant promise of this strategy for creating novel stationary phases for LC. PMID:27203513

  14. Accelerated subcritical drying of large alkoxide silica gels

    NASA Astrophysics Data System (ADS)

    Wang, Shiho; Kirkbir, Fikret; Chaudhuri, S. R.; Sarkar, Arnab

    1992-12-01

    Fracture during drying has been the key hurdle in fabrication of large monolithic silica glass from alkoxide gels. Although existing literature suggests pore enlargement, aging, chemical additives, supercritical drying and freeze drying as helpful in avoiding fracture during drying, successful accelerated sub-critical drying of large silica monoliths from alkoxide gels has not yet been reported. In the present approach, acid catalyzed sols of TEOS, ethanol and water (pH equals 2) were cast as cylindrical rods in plastic molds of 8.0 and 10.0 cm diameter with volumes of 2000 cc and 3000 cc respectively. The resultant gels were aged for about 7 days and dried in a specially designed chamber under sub-critical conditions of the pore field. We have obtained monolithic dry gels in drying times of 3 - 7 days for sizes of 2000 - 3000 cc. The dry gels have narrow unimodal pore size distributions, with average pore radius of about 20 angstroms as measured by BET. Although capillary stress during drying increases with reduction of pore size, it was found that in this approach it is easier to dry gels of smaller pore size.

  15. Activated carbon monoliths for methane storage

    NASA Astrophysics Data System (ADS)

    Chada, Nagaraju; Romanos, Jimmy; Hilton, Ramsey; Suppes, Galen; Burress, Jacob; Pfeifer, Peter

    2012-02-01

    The use of adsorbent storage media for natural gas (methane) vehicles allows for the use of non-cylindrical tanks due to the decreased pressure at which the natural gas is stored. The use of carbon powder as a storage material allows for a high mass of methane stored for mass of sample, but at the cost of the tank volume. Densified carbon monoliths, however, allow for the mass of methane for volume of tank to be optimized. In this work, different activated carbon monoliths have been produced using a polymeric binder, with various synthesis parameters. The methane storage was studied using a home-built, dosing-type instrument. A monolith with optimal parameters has been fabricated. The gravimetric excess adsorption for the optimized monolith was found to be 161 g methane for kg carbon.

  16. Silylation of low-density silica and bridged polysilsesquioxane aerogels

    SciTech Connect

    DeFriend, K. A.; Loy, D. A.; Salazar, K. V.; Wilson, K. V.

    2004-01-01

    Silica and bridged polysilsesquioxane aerogels are low-density materials that are attractive for applications such as thermal insulation, porous separation media or catalyst supports, adsorbents, and cometary dust capture agents. However, aerogels are notoriously weak and brittle making it difficult to handle and machine monoliths into desired forms. This complication prevents the development of many applications that would otherwise benefit from the use of the low-density materials. Here, we will describe our efforts to chemically modify and mechanically enhance silica-based aerogels using chemical vapor techniques without sacrificing their characteristic low densities. Monolithic silica and organic-bridged polysilsesquioxane aerogels were prepared by sol-gel polymerization of the respective methoxysilane monomers followed by supercritical carbon dioxide drying of the gels. Then the gels were reactively modified with silylating agents to demonstrate the viability of CVD modification of aerogels, and to determine the effects of silylation of surface silanols on the morphology, surface area, and mechanical properties of the resulting aerogels.

  17. Fast preparation of a highly efficient organic monolith via photo-initiated thiol-ene click polymerization for capillary liquid chromatography.

    PubMed

    Chen, Lianfang; Ou, Junjie; Liu, Zhongshan; Lin, Hui; Wang, Hongwei; Dong, Jing; Zou, Hanfa

    2015-05-15

    A novel organic monolith was firstly prepared in a UV-transparent fused-silica capillary by a single-step approach via photo-initiated thiol-ene click polymerization reaction of 1,2,4-trivinylcyclohexane (TVCH) and pentaerythriol tetra(3-mercaptopropionate) (4SH) within 10min. The effects of both composition of prepolymerization solution and polymerization time on the morphology and permeability of monolithic column were investigated in detail. Then, the optimal condition was acquired to fabricate a homogeneous and permeable organic monolith. The chemical groups of the monolithic column were confirmed by Fourier transform infrared spectroscopy (FT-IR). The SEM graphs showed the organic monolith possessed a uniform porous structure, which promotes the highest column efficiency of ∼133,000 plates per meter for alkylbenzenes at the linear velocity of 0.65mm/s in reversed-phase liquid chromatography. Finally, the organic monolithic column was further applied for separation of basic compounds, pesticides and EPA610, indicating satisfactory separation ability.

  18. Silica-Ceria Hybrid Nanostructures

    SciTech Connect

    Munusamy, Prabhakaran; Sanghavi, Shail P.; Nachimuthu, Ponnusamy; Baer, Donald R.; Thevuthasan, Suntharampillai

    2012-04-25

    A new hybrid material system that consists of ceria attached silica nanoparticles has been developed. Because of the versatile properties of silica and versatile properties of silica and versatile properties of silica and versatile properties of silica and versatile properties of silica and versatile properties of silica and versatile properties of silica and versatile properties of silica and versatile properties of silica and versatile properties of silica and versatile properties of silica and versatile properties of silica and antioxidant properties of ceria nanoparticles, this material system is ideally suited for biomedical applications. The silica particles of size ~50nm were synthesized by the Stöber synthesis method and ceria nanoparticles of size ~2-3nm was attached to the silica surface using a hetrocoagulation method. The presence of silanol groups on the surface of silica particles mediated homogenous nucleation of ceria which were attached to silica surface by Si-O-Ce bonding. The formations of silica-ceria hybrid nanostructures were characterized by X-photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM). The HRTEM image confirms the formation of individual crystallites of ceria nanoparticles attached to the silica surface. The XPS analysis indicates that ceria nanoparticles are chemically bonded to surface of silica and possess mixture of +3 and +4 chemical states.

  19. New zwitterionic polymethacrylate monolithic columns for one- and two-dimensional microliquid chromatography.

    PubMed

    Jandera, Pavel; Staňková, Magda; Hájek, Tomáš

    2013-08-01

    We prepared 0.53 and 0.32 mm id monolithic microcolumns by in situ copolymerization of a zwitterionic sulfobetaine functional monomer with bisphenol A glycerolate dimethacrylate (BIGDMA) and dioxyethylene dimetacrylate crosslinkers. The columns show a dual retention mechanism (hydrophilic-interaction mode) in acetonitrile-rich mobile phases and RP in highly aqueous mobile phases. The new 0.53 mm id columns provided excellent reproducibility, retention, and separation selectivity for phenolic acids and flavonoids. The new zwitterionic monolithic columns are highly orthogonal, with respect to alkyl silica stationary phases, not only in the hydrophilic-interaction mode but also in the RP mode. The optimized monolithic zwitterionic microcolumn of 0.53 mm id was employed in the first dimension, either in the aqueous normal-phase or in the RP mode, coupled with a short nonpolar core-shell column in the second dimension, for comprehensive 2D LC separations of phenolic and flavonoid compounds. When the 2D setup with the sulfobetaine-BIGDMA column was used for repeated sample analysis, with alternating gradients of decreasing (hydrophilic-interaction mode), and increasing (RP mode) concentration of acetonitrile on the sulfobetaine-BIGDMA column in the first dimension, useful complementary information on the sample could be obtained. PMID:23729220

  20. Effect of Polishing Systems on Surface Roughness and Topography of Monolithic Zirconia.

    PubMed

    Goo, C L; Yap, Auj; Tan, Kbc; Fawzy, A S

    2016-01-01

    This study evaluated the effect of different chairside polishing systems on the surface roughness and topography of monolithic zirconia. Thirty-five monolithic zirconia specimens (Lava PLUS, 3M ESPE) were fabricated and divided into five groups of seven and polished with the following: Group 1 (WZ)-Dura white stone followed by Shofu zirconia polishing kit; Group 2 (SZ)-Shofu zirconia polishing kit; Group 3 (CE)-Ceramiste porcelain polishers; Group 4 (CM)-Ceramaster porcelain polishers; and Group 5 (KZ)-Komet ZR zirconia polishers. All specimens were ground with a fine-grit diamond bur prior to polishing procedures to simulate clinical finishing. Baseline and post-polishing profilometric readings were recorded and delta Ra values (difference in mean surface roughness before and after polishing) were computed and analyzed using one-way analysis of variance and Scheffe post hoc test (p<0.05). Representative scanning electron microscopy (SEM) images of the ground but unpolished and polished specimens were acquired. Delta Ra values ranged from 0.146 for CE to 0.400 for KZ. Delta Ra values for KZ, WZ, and SZ were significantly greater than for CE. Significant differences in delta Ra values were also observed between KZ and CM. The SEM images obtained were consistent with the profilometric findings. Diamond-impregnated polishing systems were more effective than silica carbide-impregnated ones in reducing the surface roughness of ground monolithic zirconia. PMID:26666390

  1. Silica suspension and coating developments for Advanced LIGO

    NASA Astrophysics Data System (ADS)

    Cagnoli, G.; Armandula, H.; Cantley, C. A.; Crooks, D. R. M.; Cumming, A.; Elliffe, E.; Fejer, M. M.; Gretarsson, A. M.; Harry, G. M.; Heptonstall, A.; Hough, J.; Jones, R.; Mackowski, J.-M.; Martin, I.; Murray, P.; Penn, S. D.; Perreur-Lloyd, M.; Reid, S.; Route, R.; Rowan, S.; Robertson, N. A. A.; Sneddon, P. H.; Strain, K. A.

    2006-03-01

    The proposed upgrade to the LIGO detectors to form the Advanced LIGO detector system is intended to incorporate a low thermal noise monolithic fused silica final stage test mass suspension based on developments of the GEO 600 suspension design. This will include fused silica suspension elements jointed to fused silica test mass substrates, to which dielectric mirror coatings are applied. The silica fibres used for GEO 600 were pulled using a Hydrogen-Oxygen flame system. This successful system has some limitations, however, that needed to be overcome for the more demanding suspensions required for Advanced LIGO. To this end a fibre pulling machine based on a CO2 laser as the heating element is being developed in Glasgow with funding from EGO and PPARC. At the moment a significant limitation for proposed detectors like Advanced LIGO is expected to come from the thermal noise of the mirror coatings. An investigation on mechanical losses of silica/tantala coatings was carried out by several labs involved with Advanced LIGO R&D. Doping the tantala coating layer with titania was found to reduce the coating mechanical dissipation. A review of the results is given here.

  2. Interactions of silica surfaces

    SciTech Connect

    Vigil, G.; Xu, Z.; Steinberg, S.; Israelachvili, J. . Dept. of Chemical and Nuclear Engineering and Materials Dept.)

    1994-07-01

    Adhesion, friction, and colloidal forces in air and aqueous salt solutions have been measured between various silica surfaces prepared by depositing amorphous but highly smooth silica films on mica. The results show four interesting and interrelated phenomena: (i) the adhesion of silica surfaces in air increases slowly with contact time, especially in humid air where the contacting surfaces become separated by an [approximately]20-[angstrom]-thick layer of hydrated silica or silica gel; (ii) the friction of two silica surfaces exhibits large sticking or stiction spikes, whose magnitude increases in the presence of water and when the surfaces are kept in contact longer before sliding; (iii) the non-DLVO repulsion commonly seen at short range (<40 A) between silica surfaces immersed in aqueous solutions is monotonically repulsive, with no oscillatory component, and is quite unlike theoretical expectations and previous measurements of forces due to solvent structure; (iv) dynamic contact angle measurements reveal time-dependent effects which cannot be due to a fixed surface chemical heterogeneity or roughness. The results indicate that silica surfaces undergo slow structural and chemical changes during interactions with water and with each other. More specifically, the authors propose that the unusual interfacial and colloidal properties of silica are due, not to hydration effects, but to the presence of an [approximately]10-[angstrom]-thick gel-like layer of protruding silanol and silicilic acid groups that grow on the surfaces in the presence of water. These protruding groups react chemically (sinter) with similar groups located on an opposing surface and give rise to the unusual time-dependent adhesion, friction, and non-DLVO forces observed. The proposed mechanism in terms of a surface layer of silica gel is consistent with the known surface chemistry of silica and accounts for the results reported and for other unusual surface and colloidal properties of silica.

  3. Taking a Large Monolith to Use for Teaching Soil Morphology.

    ERIC Educational Resources Information Center

    Smith, B. R.; And Others

    1989-01-01

    Described is a technique for taking a large monolith for the purpose of teaching soil structure. Materials and procedures are detailed. A survey of 93 students indicated that the larger monolith was preferred over the commonly used narrow ones. (CW)

  4. GaAs monolithic RF modules for SARSAT distress beacons

    NASA Technical Reports Server (NTRS)

    Cauley, Michael A.

    1991-01-01

    Monolithic GaAs UHF components for use in SARSAT Emergency Distress beacons are under development by Microwave Monolithics, Inc., Simi Valley, CA. The components include a bi-phase modulator, driver amplifier, and a 5 watt power amplifier.

  5. Silica, silicosis, and cancer

    SciTech Connect

    Goldsmith, D.F.; Winn, D.M.; Shy, C.M.

    1986-01-01

    These proceedings collect papers on occupational exposure. Topics include: measurement of silica dust, mortality in granite workers, effects of quartz in coal mine dust, pneumoconiosis, and lung cancer.

  6. Designing Catalytic Monoliths For Closed-Cycle CO2 Lasers

    NASA Technical Reports Server (NTRS)

    Guinn, Keith; Herz, Richard K.; Goldblum, Seth; Noskowski, ED

    1992-01-01

    LASCAT (Design of Catalytic Monoliths for Closed-Cycle Carbon Dioxide Lasers) computer program aids in design of catalyst in monolith by simulating effects of design decisions on performance of laser. Provides opportunity for designer to explore tradeoffs among activity and dimensions of catalyst, dimensions of monolith, pressure drop caused by flow of gas through monolith, conversion of oxygen, and other variables. Written in FORTRAN 77.

  7. Consolidation and densification methods for fibrous monolith processing

    SciTech Connect

    Sutaria, Manish P.; Rigali, Mark J.; Cipriani, Ronald A.; Artz, Gregory J.; Mulligan, Anthony C.

    2006-06-20

    Methods for consolidation and densification of fibrous monolith composite structures are provided. Consolidation and densification of two- and three-dimensional fibrous monolith components having complex geometries can be achieved by pressureless sintering. The fibrous monolith composites are formed from filaments having at least a first material composition generally surrounded by a second material composition. The composites are sintered at a pressure of no more than about 30 psi to provide consolidated and densified fibrous monolith composites.

  8. Development of a monolithic ferrite memory array

    NASA Technical Reports Server (NTRS)

    Heckler, C. H., Jr.; Bhiwandker, N. C.

    1972-01-01

    The results of the development and testing of ferrite monolithic memory arrays are presented. This development required the synthesis of ferrite materials having special magnetic and physical characteristics and the development of special processes; (1) for making flexible sheets (laminae) of the ferrite composition, (2) for embedding conductors in ferrite, and (3) bonding ferrite laminae together to form a monolithic structure. Major problems encountered in each of these areas and their solutions are discussed. Twenty-two full-size arrays were fabricated and fired during the development of these processes. The majority of these arrays were tested for their memory characteristics as well as for their physical characteristics and the results are presented. The arrays produced during this program meet the essential goals and demonstrate the feasibility of fabricating monolithic ferrite memory arrays by the processes developed.

  9. A 30 GHz monolithic receive module

    NASA Technical Reports Server (NTRS)

    Mondal, J.; Contolatis, T.; Geddes, J.; Bauhahn, P.; Sokolov, V.

    1990-01-01

    The technical achievements and deliveries made during the duration of the program to develop a 30 GHz monolithic receive module for communication feed array applications and to deliver submodules and 30 GHz monolithic receive modules for experimental evaluation are discussed. Key requirements include an overall receive module noise figure of 5 dB, a 30 dB RF-to-RF gain with six levels of intermediate gain control, a five bit phase shifter, and a maximum power consumption of 250 mW. In addition, the monolithic receive module design addresses a cost goal of less than one thousand dollars (1980 dollars) per module in unit buys of 5,000 or more, and a mechanical configuration that is applicable to a spaceborne phase array system. An additional task for the development and delivery of 32 GHz phase shifter integrated circuit (IC) for deep space communication is also described.

  10. Monolithic and mechanical multijunction space solar cells

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Flood, Dennis J.

    1992-01-01

    High-efficiency, lightweight, radiation-resistant solar cells are essential to meet the large power requirements of future space missions. Single-junction cells are limited in efficiency. Higher cell efficiencies could be realized by developing multijunction, multibandgap solar cells. Monolithic and mechanically stacked tandem solar cells surpassing single-junction cell efficiencies have been fabricated. This article surveys the current status of monolithic and mechanically stacked multibandgap space solar cells, and outlines problems yet to be resolved. The monolithic and mechanically stacked cells each have their own problems related to size, processing, current and voltage matching, weight, and other factors. More information is needed on the effect of temperature and radiation on the cell performance. Proper reference cells and full-spectrum range simulators are also needed to measure efficiencies correctly. Cost issues are not addressed, since the two approaches are still in the developmental stage.

  11. The 30-GHz monolithic receive module

    NASA Technical Reports Server (NTRS)

    Bauhahn, P.; Geddes, J.; Sokolov, V.; Contolatis, T.

    1988-01-01

    The fourth year progress is described on a program to develop a 27.5 to 30 GHz GaAs monolithic receive module for spaceborne-communication antenna feed array applications, and to deliver submodules for experimental evaluation. Program goals include an overall receive module noise figure of 5 dB, a 30 dB RF to IF gain with six levels of intermediate gain control, a five bit phase shifter, and a maximum power consumption of 250 mW. Submicron gate length single and dual gate FETs are described and applied in the development of monolithic gain control amplifiers and low noise amplifiers. A two-stage monolithic gain control amplifier based on ion implanted dual gate MESFETs was designed and fabricated. The gain control amplifier has a gain of 12 dB at 29 GHz with a gain control range of over 13 dB. A two-stage monolithic low noise amplifier based on ion implanted MESFETs which provides 7 dB gain with 6.2 dB noise figure at 29 GHz was also developed. An interconnected receive module containing LNA, gain control, and phase shifter submodules was built using the LNA and gain control ICs as well as a monolithic phase shifter developed previously under this program. The design, fabrication, and evaluation of this interconnected receiver is presented. Progress in the development of an RF/IF submodule containing a unique ion implanted diode mixer diode and a broadband balanced mixer monolithic IC with on-chip IF amplifier and the initial design of circuits for the RF portion of a two submodule receiver are also discussed.

  12. Polymer network/carbon layer on monolith support and monolith catalytic reactor

    DOEpatents

    Nordquist, Andrew Francis; Wilhelm, Frederick Carl; Waller, Francis Joseph; Machado, Reinaldo Mario

    2003-08-26

    The present invention relates to an improved monolith catalytic reactor and a monolith support. The improvement in the support resides in a polymer network/carbon coating applied to the surface of a porous substrate and a catalytic metal, preferably a transition metal catalyst applied to the surface of the polymer network/carbon coating. The monolith support has from 100 to 800 cells per square inch and a polymer network/carbon coating with surface area of from 0.1 to 15 m.sup.2 /gram as measured by adsorption of N.sub.2 or Kr using the BET method.

  13. Quest for organic polymer-based monolithic columns affording enhanced efficiency in high performance liquid chromatography separations of small molecules in isocratic mode.

    PubMed

    Svec, Frantisek

    2012-03-01

    The separations of small molecules using columns containing porous polymer monoliths invented two decades ago went a long way from the very modest beginnings to the current capillary columns with efficiencies approaching those featured by their silica-based counterparts. This review article presents a variety of techniques that have been used to form capillary formats of monolithic columns with enhanced separation performance in isocratic elutions. The following text first describes the traditional approaches used for the preparation of efficient monoliths comprising variations in polymerization conditions including temperature as well as composition of monomers and porogenic solvents. Encouraging results of these experiments fueled research of completely new preparation methods such as polymerization to an incomplete conversion, use of single crosslinker, hypercrosslinking, and incorporation of carbon nanotubes that are described in the second part of the text. PMID:21816401

  14. UPDATE ON MONOLITHIC FUEL FABRICATION METHODS

    SciTech Connect

    C. R. Clark; J. F. Jue; G. A. Moore; N. P. Hallinan; B. H. Park; D. E. Burkes

    2006-10-01

    Efforts to develop a viable monolithic research reactor fuel plate have continued at Idaho National Laboratory. These efforts have concentrated on both fabrication process refinement and scale-up to produce full sized fuel plates. Progress at INL has led to fabrication of hot isostatic pressed uranium-molybdenum bearing monolithic fuel plates. These miniplates are part of the RERTR-8 miniplate irradiation test. Further progress has also been made on friction stir weld processing which has been used to fabricate full size fuel plates which will be irradiated in the ATR and OSIRIS reactors.

  15. Rapid "one-pot" preparation of polymeric monolith via photo-initiated thiol-acrylate polymerization for capillary liquid chromatography.

    PubMed

    Bai, Jingyao; Wang, Hongwei; Ou, Junjie; Liu, Zhongshan; Shen, Yehua; Zou, Hanfa

    2016-06-21

    A facile approach was exploited for fast preparation of polymer-based monoliths in UV-transparent fused-silica capillaries via "one-pot" photo-initiated thiol-acrylate polymerization reaction of dipentaerythritolpenta-/hexaacrylate (DPEPA) and 1-octadecanethiol (ODT) in the presence of porogenic solvents (1-butanol and ethylene glycol). Due to relative insensitivity of oxygen inhibition in thiol-ene free-radical polymerization, the polymerization could be performed within 5 min. The effects of composition of prepolymerization solution on the morphology and permeability of poly(ODT-co-DPEPA) monoliths were investigated in detail by adjusting the content of monomer and binary porogen ratio. The physical properties of poly(ODT-co-DPEPA) monoliths were characterized by Fourier transform infrared spectroscopy (FT-IR), mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption measurement. The evaluation of chromatographic performance was carried out by capillary liquid chromatography (cLC). The results indicated that the poly(ODT-co-DPEPA) monolith was homogeneous and permeable, and also possessed a typical reversed-phase retention mechanism in cLC with high efficiency (∼75,000 N m(-1)) for separation of alkylbenzenes. Eventually, the further separation of tryptic digest of proteins by cLC tandem mass spectrometry (cLC-MS/MS) demonstrated its potential in the analysis of biological samples. PMID:27188321

  16. Rapid "one-pot" preparation of polymeric monolith via photo-initiated thiol-acrylate polymerization for capillary liquid chromatography.

    PubMed

    Bai, Jingyao; Wang, Hongwei; Ou, Junjie; Liu, Zhongshan; Shen, Yehua; Zou, Hanfa

    2016-06-21

    A facile approach was exploited for fast preparation of polymer-based monoliths in UV-transparent fused-silica capillaries via "one-pot" photo-initiated thiol-acrylate polymerization reaction of dipentaerythritolpenta-/hexaacrylate (DPEPA) and 1-octadecanethiol (ODT) in the presence of porogenic solvents (1-butanol and ethylene glycol). Due to relative insensitivity of oxygen inhibition in thiol-ene free-radical polymerization, the polymerization could be performed within 5 min. The effects of composition of prepolymerization solution on the morphology and permeability of poly(ODT-co-DPEPA) monoliths were investigated in detail by adjusting the content of monomer and binary porogen ratio. The physical properties of poly(ODT-co-DPEPA) monoliths were characterized by Fourier transform infrared spectroscopy (FT-IR), mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption measurement. The evaluation of chromatographic performance was carried out by capillary liquid chromatography (cLC). The results indicated that the poly(ODT-co-DPEPA) monolith was homogeneous and permeable, and also possessed a typical reversed-phase retention mechanism in cLC with high efficiency (∼75,000 N m(-1)) for separation of alkylbenzenes. Eventually, the further separation of tryptic digest of proteins by cLC tandem mass spectrometry (cLC-MS/MS) demonstrated its potential in the analysis of biological samples.

  17. Carbon Nanofiber Incorporated Silica Based Aerogels with Di-Isocyanate Cross-Linking

    NASA Technical Reports Server (NTRS)

    Vivod, Stephanie L.; Meador, Mary Ann B.; Capadona, Lynn A.; Sullivan, Roy M.; Ghosn, Louis J.; Clark, Nicholas; McCorkle, Linda

    2008-01-01

    Lightweight materials with excellent thermal insulating properties are highly sought after for a variety of aerospace and aeronautic applications. (1) Silica based aerogels with their high surface area and low relative densities are ideal for applications in extreme environments such as insulators for the Mars Rover battery. (2) However, the fragile nature of aerogel monoliths prevents their widespread use in more down to earth applications. We have shown that the fragile aerogel network can be cross-linked with a di-isocyanate via amine decorated surfaces to form a conformal coating. (3) This coating reinforces the neck regions between secondary silica particles and significantly strengthens the aerogels with only a small effect on density or porosity. Scheme 1 depicts the cross-linking reaction with the di-isocyanate and exhibits the stages that result in polymer cross-linked aerogel monoliths.

  18. Epoxy Crosslinked Silica Aerogels (X-Aerogels)

    NASA Technical Reports Server (NTRS)

    fabrizio, Eve; Ilhan, Faysal; Meador, Mary Ann; Johnston, Chris; Leventis, Nicholas

    2004-01-01

    NASA is interested in the development of strong lightweight materials for the dual role of thermal insulator and structural component for space vehicles; freeing more weight for useful payloads. Aerogels are very-low density materials (0.010 to 0.5 g/cc) that, due to high porosity (meso- and microporosity), can be, depending on the chemical nature of the network, ideal thermal insulators (thermal conductivity approx. 15 mW/mK). However, aerogels are extremely fragile. For practical application of aerogels, one must increase strength without compromising the physical properties attributed to low density. This has been achieved by templated growth of an epoxy polymer layer that crosslinks the "pearl necklace" network of nanoparticles: the framework of a typical silica aerogel. The requirement for conformal accumulation of the epoxy crosslinker is reaction both with the surface of silica and with itself. After cross-linking, the strength of a typical aerogel monolith increases by a factor of 200, in the expense of only a 2-fold increase in density. Strength is increased further by coupling residual unreacted epoxides with diamine.

  19. Activity of double wash-coat monolith catalyst with noble metals and zeolites in selective catalytic reduction of NO(x) with C3H6.

    PubMed

    Lee, Jung-Dae; Kim, Ki-Joong; Kim, Yong-Hwa; Jeon, Gyung-Soo; Choi, Young-Key; Ahn, Ho-Geun

    2008-10-01

    The selective catalytic reduction (SCR) of NO(x) with C3H6 was studied in the presence of oxygen. The double wash-coat monolith catalysts for SCR comprised a lower layer of Au (or Pt)/Al2O3 and a upper layer of zeolites. The catalytic performance of the double wash-coated catalyst was remarkably improved to broaden the temperature window. The Au and Pt particles were dispersed uniformly on the monolith with particle sizes range of 3 approximately 5 nm and 5 approximately 10 nm, respectively. The catalyst binders used were colloidal silica, potassium silicate and tetraethyl orthosilicate, and the best catalyst activity was achieved with using colloidal silica as a binder. The zeolites used for the catalyst upper layer were MCM-41, FER, Y5.3-Zeolite and ZSM5, among which the NH4-ZSM5-coated catalyst showed the highest activity. The experimental results confirmed the promising potential of the double wash-coat, monolith catalyst for SCR of NO(x) with C3H6 due to the effective combination of noble metal monolith catalyst with zeolite for the removal of NO(x) by SCR with hydrocarbons.

  20. Silica, Silicosis, and Autoimmunity

    PubMed Central

    Pollard, Kenneth Michael

    2016-01-01

    Inhalation of dust containing crystalline silica is associated with a number of acute and chronic diseases including systemic autoimmune diseases. Evidence for the link with autoimmune disease comes from epidemiological studies linking occupational exposure to crystalline silica dust with the systemic autoimmune diseases systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. Although little is known regarding the mechanism by which silica exposure leads to systemic autoimmune disease, there is a voluminous literature on silica exposure and silicosis that may help identify immune processes that precede development of autoimmunity. The pathophysiology of silicosis consists of deposition of silica particles in the alveoli of the lung. Ingestion of these particles by macrophages initiates an inflammatory response, which stimulates fibroblasts to proliferate and produce collagen. Silica particles are encased by collagen leading to fibrosis and the nodular lesions characteristic of the disease. The steps in the development of silicosis, including acute and chronic inflammation and fibrosis, have different molecular and cellular requirements, suggesting that silica-induced inflammation and fibrosis may be mechanistically separate. Significantly, it is unclear whether silica-induced inflammation and fibrosis contribute similarly to the development of autoimmunity. Nonetheless, the findings from human and animal model studies are consistent with an autoimmune pathogenesis that begins with activation of the innate immune system leading to proinflammatory cytokine production, pulmonary inflammation leading to activation of adaptive immunity, breaking of tolerance, and autoantibodies and tissue damage. The variable frequency of these immunological features following silica exposure suggests substantial genetic involvement and gene/environment interaction in silica-induced autoimmunity. However, numerous questions remain unanswered. PMID:27014276

  1. Polymer monoliths synthesized by radiation co-polymerization in solution

    NASA Astrophysics Data System (ADS)

    Beiler, Barbara; Sáfrány, Ágnes

    2007-08-01

    Hydrophilic co-polymer monoliths were prepared by irradiating alcoholic solutions containing diethyleneglycol dimethacrylate (DEGDMA) and 2-hydroxyethylacrylate (HEA) monomers. The effect of monomer ratio, solvent properties and radiation dose on the porous properties of the monoliths was studied in detail and compared to the monolith prepared from DEGDMA. Increase of the HEA content in the co-monomer mixture (up to 18 vol%) resulted in monoliths with increased pore size and hydrophilic character. The biggest pores were obtained when methanol was used as solvent. The use of the monoliths as chromatographic columns for separation of proteins, amino and nucleic acids is also reported.

  2. Friction and Wear of Monolithic and Fiber Reinforced Silicon-Ceramics Sliding Against IN-718 Alloy at 25 to 800 C in Atmospheric Air at Ambient Pressure

    NASA Technical Reports Server (NTRS)

    Deadmore, Daniel L.; Sliney, Harold E.

    1988-01-01

    The friction and wear of monolithic and fiber reinforced Si-ceramics sliding against the nickel base alloy IN-718 at 25 to 800 C was measured. The monolithic materials tested were silicon carbide (SiC), fused silica (SiO2), syalon, silicon nitride (Si3N4) with W and Mg additives, and Si3N4 with Y2O3 additive. At 25 C fused silica had the lowest friction while Si3N4 (W,Mg type) had the lowest wear. At 800 C syalon had the lowest friction while Si3N4 (W,Mg type) and syalon had the lowest wear. The SiC/IN-718 couple had the lowest total wear at 25 C. At 800 C the fused silica/IN-718 couple exhibited the least total wear. SiC fiber reinforced reaction bonded silicon nitride (RBSN) composite material with a porosity of 32 percent and a fiber content of 23 vol percent had a lower coefficient of friction and wear when sliding parallel to the fiber direction than in the perpendicular at 25 C. The coefficient of friction for the carbon fiber reinforced borosilicate composite was 0.18 at 25 C. This is the lowest of all the couples tested. Wear of this material was about two decades smaller than that of the monolithic fused silica. This illustrates the large improvement in tribological properties which can be achieved in ceramic materials by fiber reinforcement. At higher temperatures the oxidation products formed on the IN-718 alloy are transferred to the ceramic by sliding action and forms a thin, solid lubricant layer which decreases friction and wear for both the monolithic and fiber reinforced composites.

  3. Constant capacitance in nanopores of carbon monoliths.

    PubMed

    García-Gómez, Alejandra; Moreno-Fernández, Gelines; Lobato, Belén; Centeno, Teresa A

    2015-06-28

    The results obtained for binder-free electrodes made of carbon monoliths with narrow micropore size distributions confirm that the specific capacitance in the electrolyte (C2H5)4NBF4/acetonitrile does not depend significantly on the micropore size and support the foregoing constant result of 0.094 ± 0.011 F m(-2).

  4. Package Holds Five Monolithic Microwave Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Mysoor, Narayan R.; Decker, D. Richard; Olson, Hilding M.

    1996-01-01

    Packages protect and hold monolithic microwave integrated circuit (MMIC) chips while providing dc and radio-frequency (RF) electrical connections for chips undergoing development. Required to be compact, lightweight, and rugged. Designed to minimize undesired resonances, reflections, losses, and impedance mismatches.

  5. Quasi-monolithic tunable optical resonator

    NASA Technical Reports Server (NTRS)

    Arbore, Mark (Inventor); Tapos, Francisc (Inventor)

    2003-01-01

    An optical resonator has a piezoelectric element attached to a quasi-monolithic structure. The quasi-monolithic structure defines an optical path. Mirrors attached to the structure deflect light along the optical path. The piezoelectric element controllably strains the quasi-monolithic structure to change a length of the optical path by about 1 micron. A first feedback loop coupled to the piezoelectric element provides fine control over the cavity length. The resonator may include a thermally actuated spacer attached to the cavity and a mirror attached to the spacer. The thermally actuated spacer adjusts the cavity length by up to about 20 microns. A second feedback loop coupled to the sensor and heater provides a coarse control over the cavity length. An alternative embodiment provides a quasi-monolithic optical parametric oscillator (OPO). This embodiment includes a non-linear optical element within the resonator cavity along the optical path. Such an OPO configuration is broadly tunable and capable of mode-hop free operation for periods of 24 hours or more.

  6. Development of oxide fibrous monolith systems.

    SciTech Connect

    Goretta, K. C.

    1999-03-02

    Fibrous monolithic ceramics generally have a cellular structure that consists of a strong cell surrounded by a weaker boundary phase [1-5]. Fibrous monoliths (FMs) are produced from powders by conventional ceramic fabrication techniques, such as extrusion [1,2]. When properly engineered, they exhibit fail gracefully [3-5]. Several compositions of ceramics and cermets have been processed successfully in fibrous monolithic form [4]. The most thoroughly investigated fibrous monolith consists of Si{sub 3}N{sub 4} cells and a BN cell-boundary phase [3-5]. Through appropriate selection of initial powders and extrusion and hot-pressing parameters, very tough final products have been produced. The resultant high toughness is due primarily to delamination during fracture along textured platelike BN grains. The primary objectives of our program are to develop: (1) Oxide-based FMs, including new systems with improved properties; (2) FMs that can be pressureless sintered rather than hot-pressed; (3) Techniques for continuous extrusion of FM filaments, including solid freeform fabrication (SFF) for net-shape fabrication of FMs; (4) Predictive micromechanical models for FM design and performance; and (5) Ties with industrial producers and users of FMs.

  7. Purification of infective baculoviruses by monoliths.

    PubMed

    Gerster, Petra; Kopecky, Eva-Maria; Hammerschmidt, Nikolaus; Klausberger, Miriam; Krammer, Florian; Grabherr, Reingard; Mersich, Christa; Urbas, Lidija; Kramberger, Petra; Paril, Tina; Schreiner, Matthias; Nöbauer, Katharina; Razzazi-Fazeli, Ebrahim; Jungbauer, Alois

    2013-05-17

    A chromatographic process based on monoliths for purification of infective baculovirus without prior concentration step has been established. Baculovirus produced in Spodoptera frugiperda cells (Sf-9) were harvested by centrifugation, filtered through 0.8 μm filters and directly loaded onto radial 1 mL anion exchange monoliths with a channel size of 1.5-2.0 μm operated at a volumetric flow rate of one bed volume per minute. Optional an epoxy monolith was used as pre-column to reduce interfering compounds and substances influencing the capacity of anion exchange monoliths for baculovirus infectious virus could be eluted with a step gradient at salt concentrations of 440 mM NaCl. Recovery of infectious virus was highly influenced by composition and age of supernatant and ranged from 20 to >99% active baculovirus. Total protein content could be reduced to 1-8% and DNA content to 38-48% in main virus fraction. Infective virus could be 52-fold concentrated within 20.5h and simultaneously an 82-fold volume reduction was possible when loading 1150 mL (2.1×10(8) pfu/mL) onto 1 mL scale support.

  8. Direct tandem mass spectrometric analysis of amino acids in plasma using fluorous derivatization and monolithic solid-phase purification.

    PubMed

    Tamashima, Erina; Hayama, Tadashi; Yoshida, Hideyuki; Imakyure, Osamu; Yamaguchi, Masatoshi; Nohta, Hitoshi

    2015-11-10

    In this study, we developed a novel direct tandem mass spectrometric method for rapid and accurate analysis of amino acids utilizing a fluorous derivatization and purification technique. Amino acids were perfluoroalkylated with 2H,2H,3H,3H-perfluoroundecan-1-al in the presence of 2-picoline borane via reductive amination. The derivatives were purified by perfluoroalkyl-modified silica-based monolithic solid-phase extraction (monolithic F-SPE), and directly analyzed by tandem mass spectrometry using electrospray ionization without liquid chromatographic separation. The perfluoroalkyl derivatives could be sufficiently distinguished from non-fluorous compounds, i.e. the biological matrix, due to their fluorous interaction. Thus, rapid and accurate determination of amino acids was accomplished. The method was validated with human plasma samples and applied to the analysis of amino acids in the plasma of mice with maple syrup urine disease or phenylketonuria. PMID:26222276

  9. Direct tandem mass spectrometric analysis of amino acids in plasma using fluorous derivatization and monolithic solid-phase purification.

    PubMed

    Tamashima, Erina; Hayama, Tadashi; Yoshida, Hideyuki; Imakyure, Osamu; Yamaguchi, Masatoshi; Nohta, Hitoshi

    2015-11-10

    In this study, we developed a novel direct tandem mass spectrometric method for rapid and accurate analysis of amino acids utilizing a fluorous derivatization and purification technique. Amino acids were perfluoroalkylated with 2H,2H,3H,3H-perfluoroundecan-1-al in the presence of 2-picoline borane via reductive amination. The derivatives were purified by perfluoroalkyl-modified silica-based monolithic solid-phase extraction (monolithic F-SPE), and directly analyzed by tandem mass spectrometry using electrospray ionization without liquid chromatographic separation. The perfluoroalkyl derivatives could be sufficiently distinguished from non-fluorous compounds, i.e. the biological matrix, due to their fluorous interaction. Thus, rapid and accurate determination of amino acids was accomplished. The method was validated with human plasma samples and applied to the analysis of amino acids in the plasma of mice with maple syrup urine disease or phenylketonuria.

  10. Differences in porous characteristics of styrenic monoliths prepared by controlled thermal polymerization in molds of varying dimensions.

    PubMed

    Byström, Emil; Viklund, Camilla; Irgum, Knut

    2010-02-01

    Nitroxide-mediated polymerization was used as a model system for preparing styrenic monolithic materials with significant mesopore contents in different mold formats, with the aim of assessing the validity of pore characterization of capillary monoliths by analysis of parallel bulk polymerized precursor solution. Capillary monoliths were prepared in 250 microm id fused silica tubes (quadruplicate samples, in total 17 m), and the batch polymerizations were carried out in parallel in 100 microL microvials and regular 2 mL glass vials, both in quintuplicate. The monoliths recovered from the molds were characterized for their meso- and macroporous properties by nitrogen sorptiometry (three repeated runs on each sample), followed by a single analysis by mercury intrusion porosimetry. A total of 14 monolith samples were thus analyzed. A Grubbs' test identified one regular vial sample as an outlier in the sorptiometric surface area measurements, and data from this sample were consequently excluded from the pore size calculations, which are based on the same nitrogen sorption data, and also from the mercury intrusion data set. The remaining data were subjected to single factor analyses of variance analyses to test if the porous properties of the capillary monoliths were different from those of the bulk monoliths prepared in parallel. Significant differences were found between all three formats both in their meso- and macroporous properties. When the dimension was shrunk from conventional vial to capillary size, the specific surface area decreased from 52.2+/-4.7 to 34.6+/-1.7 m(2)/g. This decrease in specific surface area was accompanied by a significant shift in median diameter of the through-pores, from 310+/-3.9 to 544+/-13 nm. None of these differences were obvious from the scanning electron micrographs that were acquired for each sample type. The common practice of determining the mesopore characteristics from analysis of samples prepared by parallel bulk

  11. Quartz/fused silica chip carriers

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The primary objective of this research and development effort was to develop monolithic microwave integrated circuit (MMIC) packaging which will operate efficiently at millimeter-wave frequencies. The packages incorporated fused silica as the substrate material which was selected due to its favorable electrical properties and potential performance improvement over more conventional materials for Ka-band operation. The first step towards meeting this objective is to develop a package that meets standard mechanical and thermal requirements using fused silica and to be compatible with semiconductor devices operating up to at least 44 GHz. The second step is to modify the package design and add multilayer and multicavity capacity to allow for application specific integrated circuits (ASIC's) to control multiple phase shifters. The final step is to adapt the package design to a phased array module with integral radiating elements. The first task was a continuation of the SBIR Phase 1 work. Phase 1 identified fused silica as a viable substrate material by demonstrating various plating, machining, and adhesion properties. In Phase 2 Task 1, a package was designed and fabricated to validate these findings. Task 2 was to take the next step in packaging and fabricate a multilayer, multichip module (MCM). This package is the predecessor to the phased array module and demonstrates the ability to via fill, circuit print, laminate, and to form vertical interconnects. The final task was to build a phased array module. The radiating elements were to be incorporated into the package instead of connecting to it with wire or ribbon bonds.

  12. Monoliths: special issue in a new package.

    PubMed

    Svec, Frantisek

    2013-08-01

    Regular special issues concerning monoliths have always been a stronghold of the Journal of Separation Science. Typically, we issued a call for papers, collected and processed the submitted manuscripts, and all of them were then printed in a single issue of the journal. This approach worked to a certain limit quite acceptably but there was always a longer waiting time between the early submissions and publication. This is why we decided to do it this year differently. I claimed in my 2013 New Years Editorial: "We are living in the electronic era! Why not to make an advantage of that?" And we do. As a result, all manuscript submitted for publication in the special issue Monoliths have already been published in regular issues as soon as they were accepted. The first page of these papers includes a footnote: "This paper is included in the virtual special issue Monoliths available at the Journal of Separation Science website." All papers published with this footnote were collected in a virtual special issue accessible through the internet. This concept ruled out possible delays in publication of contributions submitted early. Since we did not have any real "special issue", there was no need for any hard deadline for submission. We just collected manuscripts submitted for the special issue Monoliths published from January to July 2013 and included them in the virtual special issue. This new approach worked very well and we published 22 excellent papers that are included in the issue available now at this website: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1615-9314/homepage/virtual_special_issue__monoliths.htm. PMID:23939823

  13. Silica Embedded Metal Hydrides

    SciTech Connect

    Heung, L.K.; Wicks, G.G.

    1998-08-01

    A method to produce silica embedded metal hydride was developed. The product is a composite in which metal hydride particles are embedded in a matrix of silica. The silica matrix is highly porous. Hydrogen gas can easily reach the embedded metal hydride particles. The pores are small so that the metal hydride particles cannot leave the matrix. The porous matrix also protects the metal hydride particles from larger and reactive molecules such as oxygen, since the larger gas molecules cannot pass through the small pores easily. Tests show that granules of this composite can absorb hydrogen readily and withstand many cycles without making fines.

  14. Electrochemical Sensors: Functionalized Silica

    SciTech Connect

    Fryxell, Glen E.; Lin, Yuehe; Yantasee, Wassana

    2009-03-24

    This chapter summarizes recent devellopment of electrochemical sensors based on functionlized mesoporous silica materials. The nanomatrials based sensors have been developed for sensitive and selective enrironmental detection of toxic heavy metal and uranium ions.

  15. Crystalline Silica Primer

    USGS Publications Warehouse

    ,

    1992-01-01

    substance and will present a nontechnical overview of the techniques used to measure crystalline silica. Because this primer is meant to be a starting point for anyone interested in learning more about crystalline silica, a list of selected readings and other resources is included. The detailed glossary, which defines many terms that are beyond the scope of this publication, is designed to help the reader move from this presentation to a more technical one, the inevitable next step.

  16. Silica, hybrid silica, hydride silica and non-silica stationary phases for liquid chromatography.

    PubMed

    Borges, Endler M

    2015-04-01

    Free silanols on the surface of silica are the "villains", which are responsible for detrimental interactions of those compounds and the stationary phase (i.e., bad peak shape, low efficiency) as well as low thermal and chemical stability. For these reasons, we began this review describing new silica and hybrid silica stationary phases, which have reduced and/or shielded silanols. At present, in liquid chromatography for the majority of analyses, reversed-phase liquid chromatography is the separation mode of choice. However, the needs for increased selectivity and increased retention of hydrophilic bases have substantially increased the interest in hydrophilic interaction chromatography (HILIC). Therefore, stationary phases and this mode of separation are discussed. Then, non-silica stationary phases (i.e., zirconium oxide, titanium oxide, alumina and porous graphitized carbon), which afford increased thermal and chemical stability and also selectivity different from those obtained with silica and hybrid silica, are discussed. In addition, the use of these materials in HILIC is also reviewed.

  17. Biomimetic superelastic graphene-based cellular monoliths.

    PubMed

    Qiu, Ling; Liu, Jeffery Z; Chang, Shery L Y; Wu, Yanzhe; Li, Dan

    2012-01-01

    Many applications proposed for graphene require multiple sheets be assembled into a monolithic structure. The ability to maintain structural integrity upon large deformation is essential to ensure a macroscopic material which functions reliably. However, it has remained a great challenge to achieve high elasticity in three-dimensional graphene networks. Here we report that the marriage of graphene chemistry with ice physics can lead to the formation of ultralight and superelastic graphene-based cellular monoliths. Mimicking the hierarchical structure of natural cork, the resulting materials can sustain their structural integrity under a load of >50,000 times their own weight and can rapidly recover from >80% compression. The unique biomimetic hierarchical structure also provides this new class of elastomers with exceptionally high energy absorption capability and good electrical conductivity. The successful synthesis of such fascinating materials paves the way to explore the application of graphene in a self-supporting, structurally adaptive and 3D macroscopic form. PMID:23212370

  18. Comparison of soil-monolith extraction techniques

    NASA Astrophysics Data System (ADS)

    Meissner, R.; Rupp, H.; Weller, U.; Vogel, H.-J.

    2009-04-01

    In the international literature the term „lysimeter" is used for different objectives, e.g. suction cups, fluxmeters, etc. According to our understanding it belongs to the direct methods to measure water and solute fluxes in soil. Depending on the scientific task the shape and dimensions of the lysimeter as well as the type of filling (disturbed or undisturbed) and the specific instrumentation can be different. In any case where water dynamics or solute transport in natural soil is considered, lysimeters should be filled with 'undisturbed' monoliths which are large enough to contain the small scale heterogeneity of a site since flow and transport is highly sensitive to soil structure. Furthermore, lysimeters with vegetation should represent the natural crop inventory and the maximum root penetration depth should be taken into account. The aim of this contribution is to give an overview about different methods for obtaining undisturbed soil monoliths, in particular about i) techniques for the vertical and ii) for the horizontal extraction and iii) to evaluate the most frequently used procedures based on X-ray tomography images. Minimal disturbance of the soil monolith during extraction and subsequence filling of the lysimeter vessel is of critical importance for establishing flow and transport conditions corresponding approximately to natural field conditions. In the past, several methods were used to extract and fill lysimeter vessels vertically - including hand digging, employing sets of trihedral scaffold with lifting blocks and ballast, or using heavy duty excavators, which could shear and cut large blocks of soil. More recently, technologies have been developed to extract cylindrical soil monoliths by using ramming equipment or screw presses. One of the great disadvantages of the mentioned methods is the compaction or settling of soil that occurs during the "hammering" or "pressing". For this reason a new technology was developed, which cuts the outline of

  19. Monolithic Flexure Pre-Stressed Ultrasonic Horns

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart (Inventor); Bao, Xiaoqi (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Allen, Phillip Grant (Inventor)

    2015-01-01

    A monolithic ultrasonic horn where the horn, backing, and pre-stress structures are combined in a single monolithic piece is disclosed. Pre-stress is applied by external flexure structures. The provision of the external flexures has numerous advantages including the elimination of the need for a pre-stress bolt. The removal of the pre-stress bolt eliminates potential internal electric discharge points in the actuator. In addition, it reduces the chances of mechanical failure in the actuator stacks that result from the free surface in the hole of conventional ring stacks. In addition, the removal of the stress bolt and the corresponding reduction in the overall number of parts reduces the overall complexity of the resulting ultrasonic horn actuator and simplifies the ease of the design, fabrication and integration of the actuator of the present invention into other structures.

  20. Monolithic Flexure Pre-Stressed Ultrasonic Horns

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart (Inventor); Bao, Xiaoqi (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Allen, Phillip Grant (Inventor)

    2016-01-01

    A monolithic ultrasonic horn where the horn, backing, and pre-stress structures are combined in a single monolithic piece is disclosed. Pre-stress is applied by external flexure structures. The provision of the external flexures has numerous advantages including the elimination of the need for a pre-stress bolt. The removal of the pre-stress bolt eliminates potential internal electric discharge points in the actuator. In addition, it reduces the chances of mechanical failure in the actuator stacks that result from the free surface in the hole of conventional ring stacks. In addition, the removal of the stress bolt and the corresponding reduction in the overall number of parts reduces the overall complexity of the resulting ultrasonic horn actuator and simplifies the ease of the design, fabrication and integration of the actuator of the present invention into other structures.

  1. Monolithic Optical-To-Electronic Receiver

    NASA Technical Reports Server (NTRS)

    Kunath, Richard; Mactaggert, Ross

    1994-01-01

    Monolithic optoelectronic integrated circuit converts multiplexed digital optical signals into electrical signals, separates, and distributes them to intended destinations. Developed to deliver phase and amplitude commands to monolithic microwave integrated circuits (MMIC's) at elements of millimeter-wave phased-array antenna from single optical fiber driven by external array controller. Also used in distribution of high-data-rate optical communications in local-area networks (LAN's). Notable features include options for optical or electrical clock inputs; outputs for raw data, addresses, and instructions for diagnosis; and optical-signal-detection circuit used to reduce power consumption by 80 percent between data-transmission times. Chip fabricated by processes available at many major semiconductor foundries. Distribution of digital signals in aircraft, automobiles, and ships potential application.

  2. Monolithic solid oxide fuel cell development

    NASA Technical Reports Server (NTRS)

    Myles, K. M.; Mcpheeters, C. C.

    1989-01-01

    The feasibility of the monolithic solid oxide fuel cell (MSOFC) concept has been proven, and the performance has been dramatically improved. The differences in thermal expansion coefficients and firing shrinkages among the fuel cell materials have been minimized, thus allowing successful fabrication of the MSOFC with few defects. The MSOFC shows excellent promise for development into a practical power source for many applications from stationary power, to automobile propulsion, to space pulsed power.

  3. FLUIDIZED BED STEAM REFORMER MONOLITH FORMATION

    SciTech Connect

    Jantzen, C

    2006-12-22

    Fluidized Bed Steam Reforming (FBSR) is being considered as an alternative technology for the immobilization of a wide variety of aqueous high sodium containing radioactive wastes at various DOE facilities in the United States. The addition of clay, charcoal, and a catalyst as co-reactants converts aqueous Low Activity Wastes (LAW) to a granular or ''mineralized'' waste form while converting organic components to CO{sub 2} and steam, and nitrate/nitrite components, if any, to N{sub 2}. The waste form produced is a multiphase mineral assemblage of Na-Al-Si (NAS) feldspathoid minerals with cage-like structures that atomically bond radionuclides like Tc-99 and anions such as SO{sub 4}, I, F, and Cl. The granular product has been shown to be as durable as LAW glass. Shallow land burial requires that the mineralized waste form be able to sustain the weight of soil overburden and potential intrusion by future generations. The strength requirement necessitates binding the granular product into a monolith. FBSR mineral products were formulated into a variety of monoliths including various cements, Ceramicrete, and hydroceramics. All but one of the nine monoliths tested met the <2g/m{sup 2} durability specification for Na and Re (simulant for Tc-99) when tested using the Product Consistency Test (PCT; ASTM C1285). Of the nine monoliths tested the cements produced with 80-87 wt% FBSR product, the Ceramicrete, and the hydroceramic produced with 83.3 wt% FBSR product, met the compressive strength and durability requirements for an LAW waste form.

  4. Fluidized Bed Steam Reformer (FBSR) monolith formation

    SciTech Connect

    Jantzen, C.M.

    2007-07-01

    Fluidized Bed Steam Reforming (FBSR) is being considered as an alternative technology for the immobilization of a wide variety of aqueous high sodium containing radioactive wastes at various DOE facilities in the United States. The addition of clay, charcoal, and a catalyst as co-reactants converts aqueous Low Activity Wastes (LAW) to a granular or 'mineralized' waste form while converting organic components to CO{sub 2} and steam, and nitrate/nitrite components, if any, to N{sub 2}. The waste form produced is a multiphase mineral assemblage of Na-Al-Si (NAS) feldspathoid minerals with cage-like structures that atomically bond radionuclides like Tc-99 and anions such as SO{sub 4}, I, F, and Cl. The granular product has been shown to be as durable as LAW glass. Shallow land burial requires that the mineralized waste form be able to sustain the weight of soil overburden and potential intrusion by future generations. The strength requirement necessitates binding the granular product into a monolith. FBSR mineral products were formulated into a variety of monoliths including various cements, Ceramicrete, and hydro-ceramics. All but one of the nine monoliths tested met the <2 g/m{sup 2} durability specification for Na and Re (simulant for Tc-99) when tested using the Product Consistency Test (PCT; ASTM C1285). Of the nine monoliths tested the cements produced with 80-87 wt% FBSR product, the Ceramicrete, and the hydro-ceramic produced with 83.3 wt% FBSR product, met the compressive strength and durability requirements for an LAW waste form. (authors)

  5. Update On Monolithic Fuel Fabrication Development

    SciTech Connect

    C. R Clark; J. M. Wight; G. C. Knighton; G. A. Moore; J. F. Jue

    2005-11-01

    Efforts to develop a viable monolithic research reactor fuel plate have continued at Idaho National Laboratory. These efforts have concentrated on both fabrication process refinement and scale-up to produce full sized fuel plates. Advancements have been made in the production of U-Mo foil including full sized foils. Progress has also been made in the friction stir welding and transient liquid phase bonding fabrication processes resulting in better bonding, more stable processes and the ability to fabricate larger fuel plates.

  6. Monolithic 3D CMOS Using Layered Semiconductors.

    PubMed

    Sachid, Angada B; Tosun, Mahmut; Desai, Sujay B; Hsu, Ching-Yi; Lien, Der-Hsien; Madhvapathy, Surabhi R; Chen, Yu-Ze; Hettick, Mark; Kang, Jeong Seuk; Zeng, Yuping; He, Jr-Hau; Chang, Edward Yi; Chueh, Yu-Lun; Javey, Ali; Hu, Chenming

    2016-04-01

    Monolithic 3D integrated circuits using transition metal dichalcogenide materials and low-temperature processing are reported. A variety of digital and analog circuits are implemented on two sequentially integrated layers of devices. Inverter circuit operation at an ultralow supply voltage of 150 mV is achieved, paving the way to high-density, ultralow-voltage, and ultralow-power applications. PMID:26833783

  7. Nanoporous Carbon Monoliths with Tunable Thermal Insulation and Mechanical Properties.

    PubMed

    Wang, Xiaopeng; Chen, Fenghua; Luo, Zhenhua; Li, Hao; Zhao, Tong

    2016-01-01

    In this work, nanoscale porous carbon monoliths, with excellent compressive strength and thermal insulation, were obtained with a simple method of carbonizing cured phenol-formaldehyde resin/poly(methyl methacrylate) blends. Apparent density, pore size and morphology of the carbon monoliths were tailored by changing the composition, curing process and carbonization temperature. The continuous nanopores played a key role in enhancing mechanical and thermal performance of the carbon materials. When PMMA concentration was 25%, apparent density and thermal conductivity of the nanoporous carbonaceous monoliths were obtained as low as 1.07 g · cm⁻³ and 0.42 W/(m · K), decreasing by 29.4% and 35.4% than that of carbonaceous monoliths obtained from pure PF; while compressive strength of the nanoporous carbonaceous monoliths was as high as 34 MPa, which was improved over five times than that of pure PF carbon monoliths. PMID:27398592

  8. Nanoporous Carbon Monoliths with Tunable Thermal Insulation and Mechanical Properties.

    PubMed

    Wang, Xiaopeng; Chen, Fenghua; Luo, Zhenhua; Li, Hao; Zhao, Tong

    2016-01-01

    In this work, nanoscale porous carbon monoliths, with excellent compressive strength and thermal insulation, were obtained with a simple method of carbonizing cured phenol-formaldehyde resin/poly(methyl methacrylate) blends. Apparent density, pore size and morphology of the carbon monoliths were tailored by changing the composition, curing process and carbonization temperature. The continuous nanopores played a key role in enhancing mechanical and thermal performance of the carbon materials. When PMMA concentration was 25%, apparent density and thermal conductivity of the nanoporous carbonaceous monoliths were obtained as low as 1.07 g · cm⁻³ and 0.42 W/(m · K), decreasing by 29.4% and 35.4% than that of carbonaceous monoliths obtained from pure PF; while compressive strength of the nanoporous carbonaceous monoliths was as high as 34 MPa, which was improved over five times than that of pure PF carbon monoliths.

  9. Tailoring Elastic Properties of Silica Aerogels Cross-Linked with Polystyrene

    NASA Technical Reports Server (NTRS)

    Nguyen, Baochau N.; Meador, Mary Ann B.; Tousley, Marissa E.; Shonkwiler, Brian; McCorkle, Linda; Scheiman, Daniel A.; Palczer, Anna

    2009-01-01

    The effect of incorporating an organic linking group, 1,6-bis(trimethoxysilyl)hexane (BTMSH), into the underlying silica structure of a styrene cross-linked silica aerogel is examined. Vinyltrimethoxysilane (VTMS) is used to provide a reactive site on the silica backbone for styrene polymerization. Replacement of up to 88 mol 1 of the silicon from tetramethoxyorthosilicate with silicon derived from BTMSH and VTMS during the making of silica gels improves the elastic behavior in some formulations of the crosslinked aerogels, as evidenced by measurement of the recovered length after compression of samples to 251 strain. This is especially true for some higher density formulations, which recover nearly 100% of their length after compression to 251 strain twice. The compressive modulus of the more elastic monoliths ranged from 0.2 to 3 MPa. Although some of these monoliths had greatly reduced surface areas, changing the solvent used to produce the gels from methanol to ethanol increased the surface area in one instance from 6 to 220 sq m2/g with little affect on the modulus, elastic recovery, porosity, or density.

  10. Less common applications of monoliths III. Gas chromatography

    PubMed Central

    Svec, Frantisek; Kurganov, Alexander A.

    2008-01-01

    Porous polymer monoliths emerged about two decades ago. Despite this short time, they are finding applications in a variety of fields. In addition to the most common and certainly best known use of this new category of porous media as stationary phases in liquid chromatography, monolithic materials also found their applications in other areas. This review article focuses on monoliths in capillaries designed for separations in gas chromatography. PMID:17645884

  11. Monolithic fuel cell based power source for sprint power generation

    NASA Astrophysics Data System (ADS)

    Fee, D. C.; Busch, D. E.; Dees, D. W.; Dusek, J.; Easler, T. E.; Ellingson, W. A.; Flandermeyer, B. K.; Fousek, R. J.; Heiberger, J. J.; Majumdar, S.

    A unique fuel cell (monolith) coupled with a low power nuclear reactor presents an attractive approach for SDI burst power requirements. The high power, long duration bursts, appear achievable within a single shuttle launch limitation with appropriate development of the concept. The feasibility of the monolithic fuel cell concept has been demonstrated. Small arrays (stacks) of the monolithic design have been operated for hundreds of hours. The challenge is to improve the fabrication technology so that larger array of the monolithic design can be operated.

  12. Consolidation and densification methods for fibrous monolith processing

    DOEpatents

    Sutaria, Manish P.; Rigali, Mark J.; Cipriani, Ronald A.; Artz, Gregory J.; Mulligan, Anthony C.

    2004-05-25

    Methods for consolidation and densification of fibrous monolith composite structures are provided. Consolidation and densification of two- and three-dimensional fibrous monolith components having complex geometries can be achieved by pressureless sintering. The fibrous monolith composites are formed from filaments having at least a first material composition generally surrounded by a second material composition. The composites are sintered in an inert gas or nitrogen gas at a pressure of no more than about 30 psi to provide consolidated and densified fibrous monolith composites.

  13. Less common applications of monoliths: Preconcentration andsolid-phase extraction

    SciTech Connect

    Svec, Frantisek

    2006-03-27

    Monolithic materials are finding their place in a variety of fields. While liquid chromatography is the most emphasized use of this new category of porous media, some other just as important applications are eclipsed by the success of monolithic columns. This review article describes all current facets of use of monoliths in preconcentration and solid-phase extraction. In addition to the typical off line use that does not seem to be the main stream application for the monolithic materials, in-line connection of the preconcentration with HPLC, electrochromatography, electrophoresis, enzymatic digestion, as well as its applications in microfluidics are presented.

  14. Kinetics of silica polymerization

    SciTech Connect

    Weres, O.; Yee, A.; Tsao, L.

    1980-05-01

    The polymerization of silicic acid in geothermal brine-like aqueous solutions to produce amorphous silica in colloidal form has been studied experimentally and theoretically. A large amount of high quality experimental data has been generated over the temperature rang 23 to 100{sup 0}C. Wide ranges of dissolved silica concentration, pH, and sodium chloride concentration were covered. The catalytic effects of fluoride and the reaction inhibiting effects of aluminum and boron were studied also. Two basic processes have been separately studied: the formation of new colloidal particles by the homogeneous nucleation process and the deposition of dissolved silica on pre-existing colloidal particles. A rigorous theory of the formation of colloidal particles of amorphous silica by homogeneous nucleation was developed. This theory employs the Lothe-Pound formalism, and is embodied in the computer code SILNUC which quantitatively models the homogeneous nucleation and growth of colloidal silica particles in more than enough detail for practical application. The theory and code were extensively used in planning the experimental work and analyzing the data produced. The code is now complete and running in its final form. It is capable of reproducing most of the experimental results to within experimental error. It is also capable of extrapolation to experimentally inaccessible conditions, i.e., high temperatures, rapidly varying temperature and pH, etc.

  15. Evidence for enhanced optical properties through plasmon resonance energy transfer in silver silica nanocomposites

    NASA Astrophysics Data System (ADS)

    Mol, Beena; Joy, Lija K.; Thomas, Hysen; Thomas, Vinoy; Joseph, Cyriac; Narayanan, T. N.; Al-Harthi, Salim; Unnikrishnan, N. V.; Anantharaman, M. R.

    2016-02-01

    Silver nanoparticles were dispersed in the pores of monolithic mesoporous silica prepared by a modified sol-gel method. Structural and microstructural analyses were carried out by Fourier transform infrared spectroscopy and transmission electron microscopy. X-ray photoelectron spectroscopy was employed to determine the chemical states of silver in the silica matrix. Optical absorption studies show the evolution absorption band around 300 nm for silver (Ag) in a silica matrix and it was found to be redshifted to 422 nm on annealing. Photoluminescence studies indicate the presence of various luminescent emitting centers corresponding to silver ions and silver dimers in the SiO2 matrix. The enhancement of absorption and photoluminescence properties is attributed to plasmon resonance energy transfer from Ag nanoparticles to luminescent species in the matrix.

  16. Robust naphthyl methacrylate monolithic column for high performance liquid chromatography of a wide range of solutes.

    PubMed

    Jonnada, Murthy; El Rassi, Ziad

    2015-08-28

    An organic monolithic column based on the co-polymerization of 2-naphthyl methacrylate (NAPM) as the functional monomer and trimethylolpropane trimethacrylate (TRIM) as the crosslinker was introduced for high performance reversed-phase liquid chromatography (RPC). The co-polymerization was performed in situ in a stainless steel column of 4.6mm i.d. in the presence of a ternary porogen consisting of 1-dodecanol and cyclohexanol. This monolithic column (referred to as naphthyl methacrylate monolithic column or NMM column) showed high mechanical stability at relatively high mobile phase flow velocity indicating that the column has excellent hydrodynamic characteristics. To characterize the NMM column, different probe molecules including alkyl benzenes, and aniline, benzene, toluene and phenol derivatives were chromatographed on the column and the results in terms of k, selectivity and plate counts were compared to those obtained on an octadecyl silica (ODS) column in order to assess the presence of π-π and hydrophobic interactions on the NMM column under otherwise the same elution conditions. The NMM column offered additional π-π interactions with aromatic molecules in addition to hydrophobic interactions under RPC elution conditions. Run-to-run and column-to-column reproducibility of solute k values were evaluated, and percent relative standard deviation of <1% and ∼2-3.5%, respectively, were obtained. Six standard proteins were readily separated on the NMM column using shallow (30min at 1.0mL/min), steep (10min at 1.0mL/min) and ultra steep (1min at 3.0mL/min) linear gradient elution at increasing ACN concentration in the mobile phase using a 10cm×4.6mm i.d. column in case of shallow and steep linear gradients and a 3cm×4.6mm i.d. column for ultra steep linear gradient.

  17. Processing and characterization of multi-cellular monolithic bioceramics for bone regenerative scaffolds

    NASA Astrophysics Data System (ADS)

    Ari-Wahjoedi, Bambang; Ginta, Turnad Lenggo; Parman, Setyamartana; Abustaman, Mohd Zikri Ahmad

    2014-10-01

    Multicellular monolithic ceramic body is a ceramic material which has many gas or liquid passages partitioned by thin walls throughout the bulk material. There are many currently known advanced industrial applications of multicellular ceramics structures i.e. as supports for various catalysts, electrode support structure for solid oxide fuel cells, refractories, electric/electronic materials, aerospace vehicle re-entry heat shields and biomaterials for dental as well as orthopaedic implants by naming only a few. Multicellular ceramic bodies are usually made of ceramic phases such as mullite, cordierite, aluminum titanate or pure oxides such as silica, zirconia and alumina. What make alumina ceramics is excellent for the above functions are the intrinsic properties of alumina which are hard, wear resistant, excellent dielectric properties, resists strong acid and alkali attacks at elevated temperatures, good thermal conductivities, high strength and stiffness as well as biocompatible. In this work the processing technology leading to truly multicellular monolithic alumina ceramic bodies and their characterization are reported. Ceramic slip with 66 wt.% solid loading was found to be optimum as impregnant to the polyurethane foam template. Mullitic ceramic composite of alumina-sodium alumino disilicate-Leucite-like phases with bulk and true densities of 0.852 and 1.241 g cm-3 respectively, pore linear density of ±35 cm-1, linear and bulk volume shrinkages of 7-16% and 32 vol.% were obtained. The compressive strength and elastic modulus of the bioceramics are ≈0.5-1.0 and ≈20 MPa respectively.

  18. Silica in alkaline brines

    USGS Publications Warehouse

    Jones, B.F.; Rettig, S.L.; Eugster, H.P.

    1967-01-01

    Analysis of sodium carbonate-bicarbonate brines from closed basins in volcanic terranes of Oregon and Kenya reveals silica contents of up to 2700 parts per million at pH's higher than 10. These high concentrations of SiO 2 can be attributed to reaction of waters with silicates, and subsequent evaporative concentration accompanied by a rise in pH. Supersaturation with respect to amorphous silica may occur and persist for brines that are out of contact with silicate muds and undersaturated with respect to trona; correlation of SiO2 with concentration of Na and total CO2 support this interpretation. Addition of moredilute waters to alkaline brines may lower the pH and cause inorganic precipitation of substantial amounts of silica.

  19. Isocyanate Cross-Linked Silica: Structurally Strong Aerogels

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas; Sotiriou-Leventis, Chariklia; Zhang, Guo-Hui; Rawashdeh, Abdel-Monem M.

    2002-01-01

    Molecular-level synergism between the silica nanoparticles of pre-formed monoliths and molecular cross-linkers inverts the relative host-guest roles in glass-polymer composites, leading to new strong low-density materials. Attempts to load gels with variable amounts of polyurethane precursors such as di-ISO and diol end-capped polybutylene adipate followed by heat treatment, washing, and supercritical drying led to opaque materials, somewhat stronger than silica but still quite brittle and much inferior to the materials described above. Direct mixing of a diisocyanate and an alcohol-free sol has been attempted recently by Yim et al. Reportedly, that procedure leads to week-long gelation times and requires an at least equally long aging period. In our attempt to add various amounts of di-ISO in a base-catalyzed sol in PC, we also noticed a week-long gelation time. The resulting aerogels were translucent but no less brittle than native silica. According to more recent studies, if propylene carbonate is replaced with acetone, it leads not only to shorter processing times, but also to much stronger gels that can tolerate loads in excess of 40 kg in the arrangement presented. We attribute that behavior to the lower viscosity of acetone, that allows faster diffusion of the di-ISO solution within the pores before di-ISO has time to react with the surface of silica. Further studies are underway to vary the chemical identity of the diisocyanate, as well as the composition and density of silica.

  20. Silica Precipitation and Lithium Sorption

    SciTech Connect

    Jay Renew

    2015-09-20

    This file contains silica precipitation and lithium sorption data from the project. The silica removal data is corrected from the previous submission. The previous submission did not take into account the limit of detection of the ICP-MS procedure.

  1. Poly(cyclooctene)-based monolithic columns for capillary high performance liquid chromatography prepared via ring-opening metathesis polymerization.

    PubMed

    Schlemmer, Bettina; Gatschelhofer, Christina; Pieber, Thomas R; Sinner, Frank M; Buchmeiser, Michael R

    2006-11-01

    Monolithic columns for capillary HPLC were prepared via ring-opening metathesis polymerization (ROMP) from cis-cyclooctene (COE), tris(cyclooct-4-enyl-1-oxy)methylsilane (CL) as monomers, 2-propanol and toluene as porogens and RuCl(2)(Py)(2)(IMesH(2))(CHC(6)H(5)) (Py=pyridine, IMesH(2)=1,3-dimesityl-4,5-dihydroimidazolin-2-ylidene) as initiator within the confines of 200 microm i.d. fused silica columns. For evaluation of the novel monolithic capillary HPLC columns, a protein standard consisting of six proteins in the molecular weight range of 5800-66000 g/mol, i.e. ribonuclease A, insulin, albumin, lysozyme, myoglobin and beta-lactoglobulin, was used. Reproducibility of synthesis was checked by determining the relative standard deviation (RSD) in retention times (t(R)), which was found to be in the range of 2.9-3.9% for all analytes. Variations in polymer kinetics were realized by adding different amounts of free pyridine and had a significant influence on the monolith's morphology, the backpressure and retention times. On the contrary, variations in monomer content and COE to CL ratio showed only minor changes on these parameters. Long-term stability of 1000 runs at 50 degrees C showed excellent stability of the columns and no significant alteration in separation performance was observed in combination with slightly decreased retention times (approx. 1.6-7.2% for all analytes).

  2. Epoxy Grout With Silica Thickener

    NASA Technical Reports Server (NTRS)

    Mcclung, C. E.

    1984-01-01

    Grout cures quickly, even in presence of hydraulic oil. Grout is mixture of aggregate particles, finely-divided silica, epoxy resin, and triethylenetetramine curing agent, with mixture containing about 85 percent silica and aggregate particle sand 15 percent resin and curing agent. Silica is thickening agent and keeps grout from sagging.

  3. Nucleic acid separations using superficially porous silica particles

    PubMed Central

    Close, Elizabeth D.; Nwokeoji, Alison O.; Milton, Dafydd; Cook, Ken; Hindocha, Darsha M.; Hook, Elliot C.; Wood, Helen; Dickman, Mark J.

    2016-01-01

    Ion pair reverse-phase liquid chromatography has been widely employed for nucleic acid separations. A wide range of alternative stationary phases have been utilised in conjunction with ion pair reverse-phase chromatography, including totally porous particles, non-porous particles, macroporous particles and monolithic stationary phases. In this study we have utilised superficially porous silica particles in conjunction with ion pair reverse-phase liquid chromatography for the analysis of nucleic acids. We have investigated a range of different pore-sizes and phases for the analysis of a diverse range of nucleic acids including oligonucleotides, oligoribonucleotides, phosphorothioate oligonucleotides and high molecular weight dsDNA and RNA. The pore size of the superficially porous silica particles was shown to significantly affect the resolution of the nucleic acids. Optimum separations of small oligonucleotides such as those generated in RNase mapping experiments were obtained with 80 Å pore sizes and can readily be interfaced with mass spectrometry analysis. Improved resolution of larger oligonucleotides (>19 mers) was observed with pore sizes of 150 Å. The optimum resolution for larger dsDNA/RNA molecules was achieved using superficially porous silica particles with pore sizes of 400 Å. Furthermore, we have utilised 150 Å pore size solid-core particles to separate typical impurities of a fully phosphorothioated oligonucleotide, which are often generated in the synthesis of this important class of therapeutic oligonucleotide. PMID:26948761

  4. Monolithic aerogels with nanoporous crystalline phases

    NASA Astrophysics Data System (ADS)

    Daniel, Christophe; Guerra, Gaetano

    2015-05-01

    High porosity monolithic aerogels with nanoporous crystalline phases can be obtained from syndiotactic polystyrene and poly(2,6-dimethyl-1,4-phenylene)oxide thermoreversible gels by removing the solvent with supercritical CO2. The presence of crystalline nanopores in the aerogels based on these polymers allows a high uptake associated with a high selectivity of volatile organic compounds from vapor phase or aqueous solutions even at very low activities. The sorption and the fast kinetics make these materials particularly suitable as sorption medium to remove traces of pollutants from water and moist air.

  5. Monolithic LTCC seal frame and lid

    DOEpatents

    Krueger, Daniel S.; Peterson, Kenneth A.; Stockdale, Dave; Duncan, James Brent; Riggs, Bristen

    2016-06-21

    A method for forming a monolithic seal frame and lid for use with a substrate and electronic circuitry comprises the steps of forming a mandrel from a ceramic and glass based material, forming a seal frame and lid block from a ceramic and glass based material, creating a seal frame and lid by forming a compartment and a plurality of sidewalls in the seal frame and lid block, placing the seal frame and lid on the mandrel such that the mandrel fits within the compartment, and cofiring the seal frame and lid block.

  6. Method of fabricating a monolithic solid oxide fuel cell

    DOEpatents

    Minh, N.Q.; Horne, C.R.

    1994-03-01

    In a two-step densifying process of making a monolithic solid oxide fuel cell, a limited number of anode-electrolyte-cathode cells separated by an interconnect layer are formed and partially densified. Subsequently, the partially densified cells are stacked and further densified to form a monolithic array. 10 figures.

  7. Method of fabricating a monolithic solid oxide fuel cell

    DOEpatents

    Minh, Nguyen Q.; Horne, Craig R.

    1994-01-01

    In a two-step densifying process of making a monolithic solid oxide fuel cell, a limited number of anode-electrolyte-cathode cells separated by an interconnect layer are formed and partially densified. Subsequently, the partially densified cells are stacked and further densified to form a monolithic array.

  8. Fibrous monoliths: Economic ceramic matrix composites from powders [Final report

    SciTech Connect

    Rigali, Mark; Sutaria, Manish; Mulligan, Anthony; Creegan, Peter; Cipriani, Ron

    1999-05-26

    The project was to develop and perform pilot-scale production of fibrous monolith composites. The principal focus of the program was to develop damage-tolerant, wear-resistant tooling for petroleum drilling applications and generate a basic mechanical properties database on fibrous monolith composites.

  9. [Applications of polymeric monoliths in separation of bio-macromolecules].

    PubMed

    Bai, Ligai; Niu, Wenjing; Yang, Gengliang

    2013-04-01

    In recent years, the applications of high performance liquid chromatographic polymeric monoliths in the separation of macromolecules have been developed. In the review, the characters and new developments of bio-macromolecules separation by using the polymeric monoliths, combining with the works in our laboratory are summarized. Moreover, related influential reports are referred.

  10. Creating deep soil core monoliths: Beyond the solum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil monoliths serve as useful teaching aids in the study of the Earth’s critical zone where rock, soil, water, air, and organisms interact. Typical monolith preparation has so far been confined to the 1 to 2-m depth of the solum. Critical ecosystem services provided by soils include materials from ...

  11. Catalytic Ignition and Upstream Reaction Propagation in Monolith Reactors

    NASA Technical Reports Server (NTRS)

    Struk, Peter M.; Dietrich, Daniel L.; Miller, Fletcher J.; T'ien, James S.

    2007-01-01

    Using numerical simulations, this work demonstrates a concept called back-end ignition for lighting-off and pre-heating a catalytic monolith in a power generation system. In this concept, a downstream heat source (e.g. a flame) or resistive heating in the downstream portion of the monolith initiates a localized catalytic reaction which subsequently propagates upstream and heats the entire monolith. The simulations used a transient numerical model of a single catalytic channel which characterizes the behavior of the entire monolith. The model treats both the gas and solid phases and includes detailed homogeneous and heterogeneous reactions. An important parameter in the model for back-end ignition is upstream heat conduction along the solid. The simulations used both dry and wet CO chemistry as a model fuel for the proof-of-concept calculations; the presence of water vapor can trigger homogenous reactions, provided that gas-phase temperatures are adequately high and there is sufficient fuel remaining after surface reactions. With sufficiently high inlet equivalence ratio, back-end ignition occurs using the thermophysical properties of both a ceramic and metal monolith (coated with platinum in both cases), with the heat-up times significantly faster for the metal monolith. For lower equivalence ratios, back-end ignition occurs without upstream propagation. Once light-off and propagation occur, the inlet equivalence ratio could be reduced significantly while still maintaining an ignited monolith as demonstrated by calculations using complete monolith heating.

  12. Preparation of polyhedral oligomeric silsesquioxane based imprinted monolith.

    PubMed

    Li, Fang; Chen, Xiu-Xiu; Huang, Yan-Ping; Liu, Zhao-Sheng

    2015-12-18

    Polyhedral oligomeric silsesquioxane (POSS) was successfully applied, for the first time, to prepare imprinted monolithic column with high porosity and good permeability. The imprinted monolithic column was synthesized with a mixture of PSS-(1-Propylmethacrylate)-heptaisobutyl substituted (MA 0702), naproxon (template), 4-vinylpyridine, and ethylene glycol dimethacrylate, in ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4). The influence of synthesis parameters on the retention factor and imprinting effect, including the amount of MA 0702, the ratio of template to monomer, and the ratio of monomer to crosslinker, was investigated. The greatest imprinting factor on the imprinted monolithic column prepared with MA 0702 was 22, about 10 times higher than that prepared in absence of POSS. The comparisons between MIP monoliths synthesized with POSS and without POSS were made in terms of permeability, column efficiency, surface morphology and pore size distribution. In addition, thermodynamic and Van Deemter analysis were used to evaluate the POSS-based MIP monolith.

  13. Polyacrylamide-based monolithic capillary column with coating of cellulose tris(3,5-dimethylphenyl-carbamate) for enantiomer separation in capillary electrochromatography.

    PubMed

    Dong, Xiaoli; Wu, Ren'an; Dong, Jing; Wu, Minghuo; Zhu, Yan; Zou, Hanfa

    2008-02-01

    A hydrophilic chiral capillary monolithic column for enantiomer separation in CEC was prepared by coating cellulose tris(3,5-dimethylphenyl-carbamate) (CDMPC) on porous hydrophilic poly(acrylamide-co-N,N'-methylene-bisacrylamide) (poly(AA-co-MBA)) monolithic matrix with confine of a fused-silica capillary. The coating conditions were optimized to obtain a stable and reproducible chiral stationary phase for CEC. The effect of organic modifier of ACN in aqueous mobile phase for the enantiomer separation by CEC was investigated, and the significant influence of ACN on the enantioresolution and electrochromatographic retention was observed. Twelve pairs of enantiomers including acidic, neutral, and basic analytes were tested and nine pairs of them were baseline-enantioresolved with acidic and basic aqueous mobile phases. A good within-column repeatability in retention time (RSD = 2.4%) and resolution (RSD = 3.2%) was obtained by consecutive injections of a neutral compound, benzoin, on a prepared chiral monolithic column, while the between-column repeatability in retention time (RSD = 6.4%) and resolution (RSD = 9.6%) was observed by column-to-column examination. The prepared monolithic stationary phase showed good stability in either acidic or basic mobile phase.

  14. Polyacrylamide-based monolithic capillary column with coating of cellulose tris(3,5-dimethylphenyl-carbamate) for enantiomer separation in capillary electrochromatography.

    PubMed

    Dong, Xiaoli; Wu, Ren'an; Dong, Jing; Wu, Minghuo; Zhu, Yan; Zou, Hanfa

    2008-02-01

    A hydrophilic chiral capillary monolithic column for enantiomer separation in CEC was prepared by coating cellulose tris(3,5-dimethylphenyl-carbamate) (CDMPC) on porous hydrophilic poly(acrylamide-co-N,N'-methylene-bisacrylamide) (poly(AA-co-MBA)) monolithic matrix with confine of a fused-silica capillary. The coating conditions were optimized to obtain a stable and reproducible chiral stationary phase for CEC. The effect of organic modifier of ACN in aqueous mobile phase for the enantiomer separation by CEC was investigated, and the significant influence of ACN on the enantioresolution and electrochromatographic retention was observed. Twelve pairs of enantiomers including acidic, neutral, and basic analytes were tested and nine pairs of them were baseline-enantioresolved with acidic and basic aqueous mobile phases. A good within-column repeatability in retention time (RSD = 2.4%) and resolution (RSD = 3.2%) was obtained by consecutive injections of a neutral compound, benzoin, on a prepared chiral monolithic column, while the between-column repeatability in retention time (RSD = 6.4%) and resolution (RSD = 9.6%) was observed by column-to-column examination. The prepared monolithic stationary phase showed good stability in either acidic or basic mobile phase. PMID:18219649

  15. Poly(glycidyl methacrylate-co-N-methylolacrylamide-co-ethylene dimethacrylate) monolith coupled to high-performance liquid chromatography for the determination of adenosine phosphates in royal jelly.

    PubMed

    Liu, Dan; Zhang, Tianbin; Cheng, Yechun; Jia, Qiong

    2014-07-01

    A polymer monolith microextraction method coupled with high-performance liquid chromatography was developed for the determination of adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate. The monolithic column was synthesized inside fused-silica capillaries using thermal initiation free-radical polymerization with glycidyl methacrylate as the monomer, ethylene dimethacrylate as the cross-linker, cyclohexanol, and 1-dodecanol as the porogen. N-Methylolacrylamide, an important hydrophilic monomer, was incorporated into the polymerization mixture to enhance the hydrophilicity of the poly(glycidyl methacrylate-co-ethylene dimethacrylate) column. The obtained poly(glycidyl methacrylate-co-N-methylolacrylamide-co-ethylene dimethacrylate) monolith was characterized by scanning electron microscopy, Fourier-transform infrared spectra, and X-ray photoelectron spectroscopy. Optimum conditions for the preconcentration and separation of the target adenosines were also investigated. Under the optimum conditions, we obtained acceptable linearities, low limits of detection, and good relative standard deviations. The developed polymer monolith microextraction with high-performance liquid chromatography method exhibited a good performance with recovery values in the range of 76.9-104.7% when applied to the determination of the adenosines in five royal jelly samples.

  16. Catastrophic failure of a monolithic zirconia prosthesis.

    PubMed

    Chang, Jae-Seung; Ji, Woon; Choi, Chang-Hoon; Kim, Sunjai

    2015-02-01

    Recently, monolithic zirconia restorations have received attention as an alternative to zirconia veneered with feldspathic porcelain to eliminate chipping failures of veneer ceramics. In this clinical report, a patient with mandibular edentulism received 4 dental implants in the interforaminal area, and a screw-retained monolithic zirconia prosthesis was fabricated. The patient also received a maxillary complete removable dental prosthesis over 4 anterior roots. At the 18-month follow-up, all of the zirconia cylinders were seen to be fractured, and the contacting abutment surfaces had lost structural integrity. The damaged abutments were replaced with new abutments, and a new prosthesis was delivered with a computer-assisted design and computer-assisted manufacturing fabricated titanium framework with denture teeth and denture base resins. At the 6-month recall, the patient did not have any problems. Dental zirconia has excellent physical properties; however, care should be taken to prevent excessive stresses on the zirconia cylinders when a screw-retained zirconia restoration is planned as a definitive prosthesis.

  17. High surface area, high permeability carbon monoliths

    SciTech Connect

    Lagasse, R.R.; Schroeder, J.L.

    1994-12-31

    The goal of this work is to prepare carbon monoliths having precisely tailored pore size distribution. Prior studies have demonstrated that poly(acrylonitrile) can be processed into a precursor having tailored macropore structure. Since the macropores were preserved during pyrolysis, this synthetic process provided a route to porous carbon having macropores with size =0.1 to 10{mu}m. No micropores of size <2 nm could be detected in the carbon, however, by nitrogen adsorption. In the present work, the authors have processed a different polymer, poly(vinylidene chloride) into a macroporous precursor, Pyrolysis produced carbon monoliths having macropores derived from the polymer precursor as well as extensive microporosity produced during the pyrolysis of the polymer. One of these carbons had BET surface area of 1,050 m{sup 2}/g and about 1.2 cc/g total pore volume, with about 1/3 of the total pore volume in micropores and the remainder in 1{mu}m macropores. No mesopores in the intermediate size range could be detected by nitrogen adsorption. Carbon materials having high surface area as well as micron size pores have potential applications as electrodes for double layer supercapacitors containing liquid electrolyte, or as efficient media for performing chemical separations.

  18. Monolithic Hydrogen Peroxide Catalyst Bed Development

    NASA Technical Reports Server (NTRS)

    Ponzo, J. B.

    2003-01-01

    With recent increased industry and government interest in rocket grade hydrogen peroxide as a viable propellant, significant effort has been expended to improve on earlier developments. This effort has been predominately centered in improving heterogeneous. typically catalyst beds; and homogeneous catalysts, which are typically solutions of catalytic substances. Heterogeneous catalyst beds have traditionally consisted of compressed wire screens plated with a catalytic substance, usually silver, and were used m many RCS applications (X-1, Mercury, and Centaur for example). Aerojet has devised a heterogeneous catalyst design that is monolithic (single piece), extremely compact, and has pressure drops equal to or less than traditional screen beds. The design consists of a bonded stack of very thin, photoetched metal plates, silver coated. This design leads to a high surface area per unit volume and precise flow area, resulting in high, stable, and repeatable performance. Very high throughputs have been demonstrated with 90% hydrogen peroxide. (0.60 lbm/s/sq in at 1775-175 psia) with no flooding of the catalyst bed. Bed life of over 900 seconds has also been demonstrated at throughputs of 0.60 lbm/s/sq in across varying chamber pressures. The monolithic design also exhibits good starting performance, short break-in periods, and will easily scale to various sizes.

  19. Hydrogel coated monoliths for enzymatic hydrolysis of penicillin G.

    PubMed

    de Lathouder, K M; Smeltink, M W; Straathof, A J J; Paasman, M A; van de Sandt, E J A X; Kapteijn, F; Moulijn, J A

    2008-08-01

    The objective of this work was to develop a hydrogel-coated monolith for the entrapment of penicillin G acylase (E. coli, PGA). After screening of different hydrogels, chitosan was chosen as the carrier material for the preparation of monolithic biocatalysts. This protocol leads to active immobilized biocatalysts for the enzymatic hydrolysis of penicillin G (PenG). The monolithic biocatalyst was tested in a monolith loop reactor (MLR) and compared with conventional reactor systems using free PGA, and a commercially available immobilized PGA. The optimal immobilization protocol was found to be 5 g l(-1) PGA, 1% chitosan, 1.1% glutaraldehyde and pH 7. Final PGA loading on glass plates was 29 mg ml(-1) gel. For 400 cpsi monoliths, the final PGA loading on functionalized monoliths was 36 mg ml(-1) gel. The observed volumetric reaction rate in the MLR was 0.79 mol s(-1) m(-3) (monolith). Apart from an initial drop in activity due to wash out of PGA at higher ionic strength, no decrease in activity was observed after five subsequent activity test runs. The storage stability of the biocatalysts is at least a month without loss of activity. Although the monolithic biocatalyst as used in the MLR is still outperformed by the current industrial catalyst (immobilized preparation of PGA, 4.5 mol s(-1) m(-3) (catalyst)), the rate per gel volume is slightly higher for monolithic catalysts. Good activity and improved mechanical strength make the monolithic bioreactor an interesting alternative that deserves further investigation for this application. Although moderate internal diffusion limitations have been observed inside the gel beads and in the gel layer on the monolith channel, this is not the main reason for the large differences in reactor performance that were observed. The pH drop over the reactor as a result of the chosen method for pH control results in a decreased performance of both the MLR and the packed bed reactor compared to the batch system. A different reactor

  20. Structure-Property Relationships in Porous 3-D Nanostructures as a Function of Preparation Conditions: Isocyanate Cross-Linked Silica Aerogels

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.; Capadona, Lynn A.; McCorkle, Linda; Padadopoulos, Demetrios S.; Leventis, Nicholas

    2007-01-01

    Sol-gel derived silica aerogels are attractive candidates for many unique thermal, optical, catalytic, and chemical applications because of their low density and high mesoporosity. However, their inherent fragility has restricted use of aerogel monoliths to applications where they are not subject to any load. We have previously reported cross-linking the mesoporous silica structure of aerogels with di-isocyanates, styrenes or epoxies reacting with amine decorated silica surfaces. These approaches have been shown to significantly increase the strength of aerogels with only a small effect on density or porosity. Though density is a prime predictor of properties such as strength and thermal conductivity for aerogels, it is becoming clear from previous studies that varying the silica backbone and size of the polymer cross-link independently can give rise to combinations of properties which cannot be predicted from density alone. Herein, we examine the effects of four processing parameters for producing this type of polymer cross-linked aerogel on properties of the resulting monoliths. We focus on the results of C-13 CP-MAS NMR which gives insight to the size and structure of polymer cross-link present in the monoliths, and relates the size of the cross-links to microstructure, mechanical properties and other characteristics of the materials obtained.

  1. Structure-Property Relationships in Porous 3-D Nanostructures as a Function of Preparation Conditions: Isocyanate Cross-Linked Silica Aerogels

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.; Capadona, Lynn A.; McCorkle, Linda; Papadopoulos, Demetrios S.; Leventis, Nicholas

    2007-01-01

    Sol-gel derived silica aerogels are attractive candidates for many unique thermal, optical, catalytic, and chemical applications because of their low density and high mesoporosity. However, their inherent fragility has restricted use of aerogel monoliths to applications where they are not subject to any load. We have previously reported cross-linking the mesoporous silica structure of aerogels with di-isocyanates, styrenes or epoxies reacting with amine decorated silica surfaces. These approaches have been shown to significantly increase the strength of aerogels with only a small effect on density or porosity. Though density is a prime predictor of properties such as strength and thermal conductivity for aerogels, it is becoming clear from previous studies that varying the silica backbone and size of the polymer cross-link independently can give rise to combinations of properties which cannot be predicted from density alone. Herein, we examine the effects of four processing parameters for producing this type of polymer cross-linked aerogel on properties of the resulting monoliths. We focus on the results of 13C CP-MAS NMR which gives insight to the size and structure of polymer cross-link present in the monoliths, and relates the size of the cross-links to microstructure, mechanical properties and other characteristics of the materials obtained.

  2. Viscoelasticity of silica gels

    SciTech Connect

    Scherer, G.W.

    1995-12-01

    The response of silica gels to mechanical loads depends on the properties of the solid phase and the permeability of the network. Understanding this behavior is essential for modeling of stresses developed during drying or heating of gels. The permeability and the mechanical properties are readily determined from a simple beam-bending experiment, by measuring the load relaxation that occurs at constant deflection. Load decay results from movement of the liquid within the network; in addition, there may be viscoelastic relaxation of the network itself. Silica gel is viscoelastic in chemically aggressive media, but in inert liquids (such as ethanol or acetone) it is elastic. Experiments show that the viscoelastic relaxation time decreases as the concentration and pH of the water in the pore liquid increase. During drying, the permeability decreases and the viscosity increases, both exhibiting a power-law dependence on density of the gel network.

  3. Rapid process for producing transparent, monolithic porous glass

    DOEpatents

    Coronado, Paul R.

    2006-02-14

    A process for making transparent porous glass monoliths from gels. The glass is produced much faster and in much larger sizes than present technology for making porous glass. The process reduces the cost of making large porous glass monoliths because: 1) the process does not require solvent exchange nor additives to the gel to increase the drying rates, 2) only moderate temperatures and pressures are used so relatively inexpensive equipment is needed, an 3) net-shape glass monoliths are possible using this process. The process depends on the use of temperature to control the partial pressure of the gel solvent in a closed vessel, resulting in controlled shrinking during drying.

  4. A decoupled monolithic projection method for natural convection problems

    NASA Astrophysics Data System (ADS)

    Pan, Xiaomin; Kim, Kyoungyoun; Lee, Changhoon; Choi, Jung-Il

    2016-06-01

    We propose an efficient monolithic numerical procedure based on a projection method for solving natural convection problems. In the present monolithic method, the buoyancy, linear diffusion, and nonlinear convection terms are implicitly advanced by applying the Crank-Nicolson scheme in time. To avoid an otherwise inevitable iterative procedure in solving the monolithic discretized system, we use a linearization of the nonlinear convection terms and approximate block lower-upper (LU) decompositions along with approximate factorization. Numerical simulations demonstrate that the proposed method is more stable and computationally efficient than other semi-implicit methods, preserving temporal second-order accuracy.

  5. Neutral, Charged and Stratified Polar Monoliths for Hydrophilic Interaction Capillary Electrochromatography

    PubMed Central

    Gunasena, Dilani N.; El Rassi, Ziad

    2013-01-01

    Novel polar monoliths were introduced for hydrophilic interaction capillary electrochromatography (HI-CEC). In one case, a neutral polar monolith resulted from the in situ polymerization of glyceryl methacrylate (GMM) and pentaerythritol triacrylate (PETA) in a ternary porogenic solvent. GMM and PETA possess hydroxyl functional groups, which impart the monolith with hydrophilic interaction sites. This monolith is designated as hydroxy monolith. Although the hydroxy monolith is neutral and void of fixed charges on the surface, a relatively strong cathodal EOF was observed due to the electric double layer formed by the adsorption of ions from the mobile phase, producing a bulk mobile phase flow. The second monolith is charged and referred to as AP-monolith that possesses amine/amide functionalities on its surface, and was prepared by the in situ polymerization of N-(3-aminopropyl) methacrylamide hydrochloride (NAPM) and ethylene dimethacrylate (EDMA) in the presence of cyclohexanol, dodecanol and methanol as porogens. Over the pH range studied a strong anodal EOF was observed. The AP-monolith was further exploited in HI-CEC by modifying its surface with neutral mono- and oligosaccharides to produce a series of the so called sugar modified AP-monoliths (SMAP-monolith), which are considered as stratified hydrophilic monoliths possessing a sub-layer of polar amine/amide groups and a top layer of sugar (a polyhydroxy top layer).The SMAP-monoliths can be viewed as a blend of both the hydroxy monolith and the AP-monolith. The polarity of the various monoliths seems to follow the order: hydroxy monolith < AP-monolith < SMAP-monolith. The novel monoliths were characterized over a wide range of elution conditions with a variety of polar solutes including phenols, substituted phenols, nucleic acid bases, nucleosides and nucleotides PMID:23972465

  6. A monolithic thin film electrochromic window

    SciTech Connect

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K.; Wei, G.; Yu, P.C.

    1991-12-31

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors` institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  7. A monolithic thin film electrochromic window

    SciTech Connect

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. . Electro-Optics Technology Center); Wei, G. ); Yu, P.C. )

    1991-01-01

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors' institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  8. Monolithic short wave infrared (SWIR) detector array

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A monolithic self-scanned linear detector array was developed for remote sensing in the 1.1- 2.4-micron spectral region. A high-density IRCCD test chip was fabricated to verify new design approaches required for the detector array. The driving factors in the Schottky barrier IRCCD (Pdsub2Si) process development are the attainment of detector yield, uniformity, adequate quantum efficiency, and lowest possible dark current consistent with radiometric accuracy. A dual-band module was designed that consists of two linear detector arrays. The sensor architecture places the floating diffusion output structure in the middle of the chip, away from the butt edges. A focal plane package was conceptualized and includes a polycrystalline silicon substrate carrying a two-layer, thick-film interconnecting conductor pattern and five epoxy-mounted modules. A polycrystalline silicon cover encloses the modules and bond wires, and serves as a radiation and EMI shield, thermal conductor, and contamination seal.

  9. Monolithic fuel injector and related manufacturing method

    DOEpatents

    Ziminsky, Willy Steve; Johnson, Thomas Edward; Lacy, Benjamin; York, William David; Stevenson, Christian Xavier

    2012-05-22

    A monolithic fuel injection head for a fuel nozzle includes a substantially hollow vesicle body formed with an upstream end face, a downstream end face and a peripheral wall extending therebetween, an internal baffle plate extending radially outwardly from a downstream end of the bore, terminating short of the peripheral wall, thereby defining upstream and downstream fuel plenums in the vesicle body, in fluid communication by way of a radial gap between the baffle plate and the peripheral wall. A plurality of integral pre-mix tubes extend axially through the upstream and downstream fuel plenums in the vesicle body and through the baffle plate, with at least one fuel injection hole extending between each of the pre-mix tubes and the upstream fuel plenum, thereby enabling fuel in the upstream plenum to be injected into the plurality of pre-mix tubes. The fuel injection head is formed by direct metal laser sintering.

  10. Monolithically Peltier-cooled laser diodes

    NASA Astrophysics Data System (ADS)

    Hava, S.; Hunsperger, R. G.; Sequeira, H. B.

    1984-04-01

    A new method of cooling a GaAs/GaAlAs laser in an optical integrated circuit or on a discrete chip, by adding an integral thermoelectric (Peltier) cooling and heat spreading device to the laser, is presented. This cooling both reduces and stabilizes the laser junction temperature to minimize such deleterious effects as wavelength drift due to heating. A unified description of the electrical and thermal properties of a monolithic semiconductor mesa structure is given. Here it is shown that an improvement in thermal characteristics is obtained by depositing a relatively thick metallic layer, and by using this layer as a part of an active Peltier structure. Experimental results reveal a 14-percent increase in emitted power (external quantum efficiency) due to passive heat spreading and a further 8-percent if its Peltier cooler is operated. Fabrication techniques used to obtain devices exhibiting the above performance characteristics are given.

  11. Monolithically Peltier-cooled laser diodes

    SciTech Connect

    Hava, S.; Hunsperger, R.G.; Sequeira, H.B.

    1984-04-01

    A new method of cooling a GaAs/GaAlAs laser in an optical integrated circuit or on a discrete chip, by adding an integral thermoelectric (Peltier) cooling and heat spreading device to the laser, is presented. This cooling both reduces and stabilizes the laser junction temperature to minimize such deleterious effects as wavelength drift due to heating. A unified description of the electrical and thermal properties of a monolithic semiconductor mesa structure is given. Here it is shown that an improvement in thermal characteristics is obtained by depositing a relatively thick metallic layer, and by using this layer as a part of an active Peltier structure. Experimental results reveal a 14-percent increase in emitted power (external quantum efficiency) due to passive heat spreading and a further 8-percent if its Peltier cooler is operated. Fabrication techniques used to obtain devices exhibiting the above performance characteristics are given. 21 references.

  12. Monolithic microwave integrated circuit water vapor radiometer

    NASA Technical Reports Server (NTRS)

    Sukamto, L. M.; Cooley, T. W.; Janssen, M. A.; Parks, G. S.

    1991-01-01

    A proof of concept Monolithic Microwave Integrated Circuit (MMIC) Water Vapor Radiometer (WVR) is under development at the Jet Propulsion Laboratory (JPL). WVR's are used to remotely sense water vapor and cloud liquid water in the atmosphere and are valuable for meteorological applications as well as for determination of signal path delays due to water vapor in the atmosphere. The high cost and large size of existing WVR instruments motivate the development of miniature MMIC WVR's, which have great potential for low cost mass production. The miniaturization of WVR components allows large scale deployment of WVR's for Earth environment and meteorological applications. Small WVR's can also result in improved thermal stability, resulting in improved calibration stability. Described here is the design and fabrication of a 31.4 GHz MMIC radiometer as one channel of a thermally stable WVR as a means of assessing MMIC technology feasibility.

  13. The fabrication of monolithic capillary column based on poly (bisphenol A epoxy vinyl ester resin-co-ethylene glycol dimethacrylate) and its applications for the separation of small molecules in high performance liquid chromatography.

    PubMed

    Niu, Wenjing; Wang, Lijuan; Bai, Ligai; Yang, Gengliang

    2013-07-01

    A new polymeric monolith was synthesized in fused-silica capillary by in situ polymerization technique. In the polymerization, bisphenol A epoxy vinyl ester resin (VER) was used as the functional monomer, ethylene glycol dimethacrylate (EDMA) as the crosslinking monomer, 1,4-butanediol, 1-propanol and water as the co-porogens, and azobisisobutyronitrile (AIBN) as the initiator. The conditions of polymerization have been optimized. Morphology of the prepared poly (VER-co-EDMA) monolith was investigated by the scanning electron microscopy (SEM); pore properties were assayed by mercury porosimetry and nitrogen adsorption. The optimized poly (VER-co-EDMA) monolith showed a uniform structure, good permeability and mechanical stability. Then, the column was used as the stationary phase of high performance liquid chromatography (HPLC) to separate the mixture of benzene derivatives. The best column efficiency achieved for phenol was 235790 theoretical plates per meter. Baseline separations of benzene derivatives and halogenated benzene compounds under optimized isocratic mode conditions were achieved with high column efficiency. The column showed good reproducibility: the relative standard deviation (RSD) values based on the retention times (n=3) for run-to-run, column-to-column and batch-to-batch were less than 0.98, 1.68, 5.48%, respectively. Compared with poly (BMA-co-EDMA) monolithic column, the proposed monolith exhibited more efficiency in the separation of small molecules. PMID:23726080

  14. 21 CFR 182.1711 - Silica aerogel.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Silica aerogel. 182.1711 Section 182.1711 Food and....1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica foam having a minimum silica content of 89.5 percent. (b) (c) Limitations, restrictions, or explanation....

  15. 21 CFR 582.1711 - Silica aerogel.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Silica aerogel. 582.1711 Section 582.1711 Food and....1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica foam having a minimum silica content of 89.5 percent. (b) (c) Limitations, restrictions, or explanation....

  16. 21 CFR 182.1711 - Silica aerogel.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Silica aerogel. 182.1711 Section 182.1711 Food and....1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica foam having a minimum silica content of 89.5 percent. (b) (c) Limitations, restrictions, or explanation....

  17. 21 CFR 582.1711 - Silica aerogel.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Silica aerogel. 582.1711 Section 582.1711 Food and....1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica foam having a minimum silica content of 89.5 percent. (b) (c) Limitations, restrictions, or explanation....

  18. 21 CFR 582.1711 - Silica aerogel.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Silica aerogel. 582.1711 Section 582.1711 Food and....1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica foam having a minimum silica content of 89.5 percent. (b) (c) Limitations, restrictions, or explanation....

  19. 21 CFR 182.1711 - Silica aerogel.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Silica aerogel. 182.1711 Section 182.1711 Food and....1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica foam having a minimum silica content of 89.5 percent. (b) (c) Limitations, restrictions, or explanation....

  20. 21 CFR 582.1711 - Silica aerogel.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Silica aerogel. 582.1711 Section 582.1711 Food and....1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica foam having a minimum silica content of 89.5 percent. (b) (c) Limitations, restrictions, or explanation....

  1. 21 CFR 182.1711 - Silica aerogel.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Silica aerogel. 182.1711 Section 182.1711 Food and....1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica foam having a minimum silica content of 89.5 percent. (b) (c) Limitations, restrictions, or explanation....

  2. 21 CFR 182.1711 - Silica aerogel.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Silica aerogel. 182.1711 Section 182.1711 Food and... GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica foam having a minimum silica content of...

  3. 21 CFR 582.1711 - Silica aerogel.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Silica aerogel. 582.1711 Section 582.1711 Food and....1711 Silica aerogel. (a) Product. Silica aerogel as a finely powdered microcellular silica foam having a minimum silica content of 89.5 percent. (b) (c) Limitations, restrictions, or explanation....

  4. Facile preparation of transparent and dense CdS-silica gel glass nanocomposites for optical limiting applications.

    PubMed

    Feng, Miao; Zhan, Hongbing

    2014-04-21

    To realize their practical and operable applications as a potential optical limiting (OL) material, quantum dots (QDs) need to have good processability by incorporating them into optical-quality matrices. This work reports a facile route for the room-temperature preparation of large, stable transparent monolithic CdS nanocomposites which can be easily extended to allow the introduction of acid-sensitive functional molecules/nanoparticles into a silica network by sol-gel chemistry. Our strategy involves a two-step sol-gel process (acid-catalyst hydrolysis and basic-catalyst condensation) and the co-condensation of the resulting alkoxysilane-capped CdS QDs with other alkoxysilanes, which allows the CdS QDs to become part of the silica covalent network. The degradation and agglomeration of CdS QDs were thereby effectively restrained, and large monolithic transparent CdS-silica gel glass was obtained. Using Z-scan theory and the resulting open-aperture Z-scan curves, the nonlinear extinction coefficient of the CdS-silica nanocomposite gel glass was calculated to be 1.02 × 10(-14) cm W(-1), comparable to that of the parent CdS QD dispersion, indicating their promise for OL applications.

  5. The world ocean silica cycle.

    PubMed

    Tréguer, Paul J; De La Rocha, Christina L

    2013-01-01

    Over the past few decades, we have realized that the silica cycle is strongly intertwined with other major biogeochemical cycles, like those of carbon and nitrogen, and as such is intimately related to marine primary production, the efficiency of carbon export to the deep sea, and the inventory of carbon dioxide in the atmosphere. For nearly 20 years, the marine silica budget compiled by Tréguer et al. (1995) , with its exploration of reservoirs, processes, sources, and sinks in the silica cycle, has provided context and information fundamental to study of the silica cycle. Today, the budget needs revisiting to incorporate advances that have notably changed estimates of river and groundwater inputs to the ocean of dissolved silicon and easily dissolvable amorphous silica, inputs from the dissolution of terrestrial lithogenic silica in ocean margin sediments, reverse weathering removal fluxes, and outputs of biogenic silica (especially on ocean margins and in the form of nondiatomaceous biogenic silica). The resulting budget recognizes significantly higher input and output fluxes and notes that the recycling of silicon occurs mostly at the sediment-water interface and not during the sinking of silica particles through deep waters.

  6. Advances in monoliths and related porous materials for microfluidics.

    PubMed

    Knob, Radim; Sahore, Vishal; Sonker, Mukul; Woolley, Adam T

    2016-05-01

    In recent years, the use of monolithic porous polymers has seen significant growth. These materials present a highly useful support for various analytical and biochemical applications. Since their introduction, various approaches have been introduced to produce monoliths in a broad range of materials. Simple preparation has enabled their easy implementation in microchannels, extending the range of applications where microfluidics can be successfully utilized. This review summarizes progress regarding monoliths and related porous materials in the field of microfluidics between 2010 and 2015. Recent developments in monolith preparation, solid-phase extraction, separations, and catalysis are critically discussed. Finally, a brief overview of the use of these porous materials for analysis of subcellular and larger structures is given. PMID:27190564

  7. 62. VIEW SHOWING INSTALLATION TAINTER VALVE MACHINERY MONOLITH NO. 321, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    62. VIEW SHOWING INSTALLATION TAINTER VALVE MACHINERY MONOLITH NO. 32-1, LOOKING WEST Photograph No. 8571. October 24, 1949 - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 27, Granite City, Madison County, IL

  8. 10. LOCK CONSTRUCTION PHOTO SHOWING CONCRETE MONOLITHS FOR WALLS, LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. LOCK CONSTRUCTION PHOTO SHOWING CONCRETE MONOLITHS FOR WALLS, LOOKING NORTH. August 1934 - Mississippi River 9-Foot Channel Project, Lock & Dam No. 16, Upper Mississippi River, Muscatine, Muscatine County, IA

  9. 25. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT UPPER END ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT UPPER END OF MAIN LOCK AND DAM PIERS, LOOKING SOUTHEAST (DOWNSTREAM). NOTE GANTRY CRANES - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  10. 53. VIEW OF ROCK FOUNDATIONS AIR CLEANED FOR MONOLITHS 1722, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    53. VIEW OF ROCK FOUNDATIONS AIR CLEANED FOR MONOLITHS 17-22, INTERMEDIATE WALL, LOOKING NORTH Photograph No. 12840. September 10, 1948 - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 27, Granite City, Madison County, IL

  11. 27. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT DOWNSTREAM END ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT DOWNSTREAM END OF WEST MAIN LOCK WALL, LOOKiNG SOUTHEAST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  12. 26. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT UPPER END ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. DETAIL VIEW OF CONCRETE MONOLITH CONSTRUCTION AT UPPER END OF MAIN LOCK AND DAM PIERS, LOOKING SOUTHEAST (DOWNSTREAM) - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

  13. Experimental and computational investigation of flow in catalytic monolith channels

    SciTech Connect

    Wilson, G.C.; Bardon, M.F.; Witton, J.J. Cranfield Inst. of Technology )

    1992-01-01

    Monolith optimization is necessary for maximum efficiency during catalytic combustion. This paper describes a study undertaken to investigate the flow in catalytic monolith channels. A super-scale model of a single passage in a ceramic catalyst monolith was constructed and studied using pure air as the working fluid. Combustion of a representative natural gas mixture at the catalyst surface was simulated by electrical heating of the channel walls. The flow-field was probed with hot wire anemometers and fine wire thermocouples to obtain velocity and temperature data. Concurrently, the PHOENICS CFD package was used to model the flow. Results confirmed the presence of secondary flows and illustrated the effects of channel shape. The results are discussed as to their relevance to the design of a monolithic combustor for gas turbine applications. 15 refs.

  14. 31. SPILLWAY CHANNEL WALLS REINF DETAILS; MONOLITHS E21 AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. SPILLWAY CHANNEL WALLS REINF - DETAILS; MONOLITHS E-21 AND W-21. Sheet S-45, May, 1940. File no. 342/58. - Prado Dam, Spillway, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  15. Developments in the use and fabrication of organic monolithic phases for use with high-performance liquid chromatography and capillary electrochromatography.

    PubMed

    Smith, Norman W; Jiang, Zhengjin

    2008-03-14

    Capillary electrochromatography suffered in its development because of difficulty in producing stable columns with good permeability. Variability in frit characteristics gave rise to non-reproducible capillaries whose fabrication was extremely difficult and time consuming. Monolithic stationary phases gained popularity in the early 1990s due to the fact that they were easy to fabricate and required no retaining frits. They were also able to be manufactured in a wide variety of chemistries which made them very interesting to the analytical chemist who is constantly looking for materials with different selectivity to the popular silica-based stationary phases.

  16. Finite element analysis of monolithic solid oxide fuel cells

    SciTech Connect

    Saigal, A. . Dept. of Mechanical Engineering); Majumdar, S. )

    1992-01-01

    This paper investigates the stress and fracture behavior of a monolithic solid oxide fuel cell (MSOFC) currently under joint development by Allied Signal Corporation and Argonne National Laboratory. The MSOFC is an all-ceramic fuel cell capable of high power density and tolerant of a variety of hydrocarbon fuels, making it potentially attractive for stationary utility and mobile transportation systems. The monolithic design eliminates inactive structural supports, increases active surface area, and lowers voltage losses caused by internal resistance.

  17. Finite element analysis of monolithic solid oxide fuel cells

    SciTech Connect

    Saigal, A.; Majumdar, S.

    1992-04-01

    This paper investigates the stress and fracture behavior of a monolithic solid oxide fuel cell (MSOFC) currently under joint development by Allied Signal Corporation and Argonne National Laboratory. The MSOFC is an all-ceramic fuel cell capable of high power density and tolerant of a variety of hydrocarbon fuels, making it potentially attractive for stationary utility and mobile transportation systems. The monolithic design eliminates inactive structural supports, increases active surface area, and lowers voltage losses caused by internal resistance.

  18. Extended Leach Testing of Simulated LAW Cast Stone Monoliths

    SciTech Connect

    Serne, R. Jeffrey; Westsik, Joseph H.; Williams, Benjamin D.; Jung, H. B.; Wang, Guohui

    2015-07-09

    This report describes the results from long-term laboratory leach tests performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate the release of key constituents from monoliths of Cast Stone prepared with four simulated low-activity waste (LAW) liquid waste streams. Specific objectives of the Cast Stone long-term leach tests described in this report focused on four activities: 1. Extending the leaching times for selected ongoing EPA-1315 tests on monoliths made with LAW simulants beyond the conventional 63-day time period up to 609 days reported herein (with some tests continuing that will be documented later) in an effort to evaluate long-term leaching properties of Cast Stone to support future performance assessment activities. 2. Starting new EPA-1315 leach tests on archived Cast Stone monoliths made with four LAW simulants using two leachants (deionized water [DIW] and simulated Hanford Integrated Disposal Facility (IDF) Site vadose zone pore water [VZP]). 3. Evaluating the impacts of varying the iodide loading (starting iodide concentrations) in one LAW simulant (7.8 M Na Hanford Tank Waste Operations Simulator (HTWOS) Average) by manufacturing new Cast Stone monoliths and repeating the EPA-1315 leach tests using DIW and the VZP leachants. 4. Evaluating the impacts of using a non-pertechnetate form of Tc that is present in some Hanford tanks. In this activity one LAW simulant (7.8 M Na HTWOS Average) was spiked with a Tc(I)-tricarbonyl gluconate species and then solidified into Cast Stone monoliths. Cured monoliths were leached using the EPA-1315 leach protocol with DIW and VZP. The leach results for the Tc-Gluconate Cast Stone monoliths were compared to Cast Stone monoliths pertechnetate.

  19. HPLC-MS/MS Analyses Show That the Near-Starchless aps1 and pgm Leaves Accumulate Wild Type Levels of ADPglucose: Further Evidence for the Occurrence of Important ADPglucose Biosynthetic Pathway(s) Alternative to the pPGI-pPGM-AGP Pathway

    PubMed Central

    Muñoz, Francisco José; Li, Jun; Almagro, Goizeder; Montero, Manuel; Pujol, Pablo; Galarza, Regina; Kaneko, Kentaro; Oikawa, Kazusato; Wada, Kaede; Mitsui, Toshiaki; Pozueta-Romero, Javier

    2014-01-01

    In leaves, it is widely assumed that starch is the end-product of a metabolic pathway exclusively taking place in the chloroplast that (a) involves plastidic phosphoglucomutase (pPGM), ADPglucose (ADPG) pyrophosphorylase (AGP) and starch synthase (SS), and (b) is linked to the Calvin-Benson cycle by means of the plastidic phosphoglucose isomerase (pPGI). This view also implies that AGP is the sole enzyme producing the starch precursor molecule, ADPG. However, mounting evidence has been compiled pointing to the occurrence of important sources, other than the pPGI-pPGM-AGP pathway, of ADPG. To further explore this possibility, in this work two independent laboratories have carried out HPLC-MS/MS analyses of ADPG content in leaves of the near-starchless pgm and aps1 mutants impaired in pPGM and AGP, respectively, and in leaves of double aps1/pgm mutants grown under two different culture conditions. We also measured the ADPG content in wild type (WT) and aps1 leaves expressing in the plastid two different ADPG cleaving enzymes, and in aps1 leaves expressing in the plastid GlgC, a bacterial AGP. Furthermore, we measured the ADPG content in ss3/ss4/aps1 mutants impaired in starch granule initiation and chloroplastic ADPG synthesis. We found that, irrespective of their starch contents, pgm and aps1 leaves, WT and aps1 leaves expressing in the plastid ADPG cleaving enzymes, and aps1 leaves expressing in the plastid GlgC accumulate WT ADPG content. In clear contrast, ss3/ss4/aps1 leaves accumulated ca. 300 fold-more ADPG than WT leaves. The overall data showed that, in Arabidopsis leaves, (a) there are important ADPG biosynthetic pathways, other than the pPGI-pPGM-AGP pathway, (b) pPGM and AGP are not major determinants of intracellular ADPG content, and (c) the contribution of the chloroplastic ADPG pool to the total ADPG pool is low. PMID:25133777

  20. Mechanically stable, hierarchically porous Cu3(btc)2 (HKUST-1) monoliths via direct conversion of copper(II) hydroxide-based monoliths.

    PubMed

    Moitra, Nirmalya; Fukumoto, Shotaro; Reboul, Julien; Sumida, Kenji; Zhu, Yang; Nakanishi, Kazuki; Furukawa, Shuhei; Kitagawa, Susumu; Kanamori, Kazuyoshi

    2015-02-28

    The synthesis of highly crystalline macro-meso-microporous monolithic Cu3(btc)2 (HKUST-1; btc(3-) = benzene-1,3,5-tricarboxylate) is demonstrated by direct conversion of Cu(OH)2-based monoliths while preserving the characteristic macroporous structure. The high mechanical strength of the monoliths is promising for possible applications to continuous flow reactors. PMID:25572361

  1. Phenylalanine functionalized zwitterionic monolith for hydrophobic interaction electrochromatography.

    PubMed

    Wang, Jiabin; Jia, Wenchao; Lin, Xucong; Wu, Xiaoping; Xie, Zenghong

    2013-12-01

    A novel phenylalanine (Phe) functionalized zwitterionic monolith for hydrophobic electrochromatography was prepared by a two-step procedure involving the synthesis of glycidyl methacrylate based polymer monolith and subsequent on-column chemical modification with Phe via ring-opening reaction of epoxides. Benefitting from the hydrophobicity of both methacrylate-based matrix and aromatic group of Phe, this monolith could exhibit good hydrophobic interaction for the separation. Typical RP chromatographic behavior was observed toward various solutes. The well-controlled cathodic or anodic EOF of the prepared column could be facilely switched by altering the pH values of running buffers. The separation mechanism of this Phe functionalized zwitterionic monolith is discussed in detail. Two mixed-mode mechanisms of RP/cation exchange and RP/anion exchange could be further realized on the same monolith in different pH condition of the mobile phase. Versatile separation capabilities of neutral, basic, and acidic analytes have been successfully achieved in this zwitterionic monolith by CEC method.

  2. Methacrylate monolith chromatography as a tool for waterborne virus removal.

    PubMed

    Rački, N; Kramberger, P; Steyer, A; Gašperšič, J; Štrancar, A; Ravnikar, M; Gutierrez-Aguirre, I

    2015-02-13

    Enteric viruses are commonly present in environmental waters and represent the major cause of waterborne infections and outbreaks. Since traditional wastewater treatments fail to remove enteric viruses in the water purification process, they are released daily into environmental waters. Monolithic supports have enabled chromatography to enter the field of virology. They have been successfully used in virus purification and concentration. In this work quaternary amine (QA) methacrylate monoliths were exploited to remove enteric viruses from wastewater treatment plant effluent. Expectedly, chromatographic processing of such a complex medium was troublesome, even for monoliths, characterized by extremely large pore dimensions. This problem was solved by introducing a pre-step chromatography using hydroxyl (OH) methacrylate monoliths. This way, molecules, that would hinder virus binding to the anion-exchanger monolith, were removed. As a result, the OH pre-column reduced backpressure increase on the subsequent anion-exchanger column, and increased both QA column binding capacity and life time. Wastewater effluent samples were successfully purified from five waterborne enteric viruses (rotavirus, norovirus genogroup I and II, astrovirus, sapovirus), below the detection limit of RT-qPCR. The breakthrough of the rotavirus binding capacity was not reached for concentrations that significantly exceeded those expected in effluent waters. The obtained results confirm that methacrylate monoliths can be a valuable tool for simultaneous removal of different waterborne viruses from contaminated water sources.

  3. Characterization of methacrylate chromatographic monoliths bearing affinity ligands.

    PubMed

    Černigoj, Urh; Vidic, Urška; Nemec, Blaž; Gašperšič, Jernej; Vidič, Jana; Lendero Krajnc, Nika; Štrancar, Aleš; Podgornik, Aleš

    2016-09-16

    We investigated effect of immobilization procedure and monolith structure on chromatographic performance of methacrylate monoliths bearing affinity ligands. Monoliths of different pore size and various affinity ligands were prepared and characterized using physical and chromatographic methods. When testing protein A monoliths with different protein A ligand densities, a significant nonlinear effect of ligand density on dynamic binding capacity (DBC) for IgG was obtained and accurately described by Langmuir isotherm curve enabling estimation of protein A utilization as a function of ligand density. Maximal IgG binding capacity was found to be at least 12mg/mL exceeding theoretical monolayer adsorption value of 7.8mg/mL assuming hexagonal packing and IgG hydrodynamic diameter of 11nm. Observed discrepancy was explained by shrinkage of IgG during adsorption on protein A experimentally determined through calculated adsorbed IgG layer thickness of 5.4nm from pressure drop data. For monoliths with different pore size maximal immobilized densities of protein A as well as IgG dynamic capacity linearly correlates with monolith surface area indicating constant ligand utilization. Finally, IgGs toward different plasma proteins were immobilized via the hydrazide coupling chemistry to provide oriented immobilization. DBC was found to be flow independent and was increasing with the size of bound protein. Despite DBC was lower than IgG capacity to immobilized protein A, ligand utilization was higher. PMID:27554023

  4. Processing and characterization of multi-cellular monolithic bioceramics for bone regenerative scaffolds

    SciTech Connect

    Ari-Wahjoedi, Bambang; Ginta, Turnad Lenggo; Parman, Setyamartana; Abustaman, Mohd Zikri Ahmad

    2014-10-24

    Multicellular monolithic ceramic body is a ceramic material which has many gas or liquid passages partitioned by thin walls throughout the bulk material. There are many currently known advanced industrial applications of multicellular ceramics structures i.e. as supports for various catalysts, electrode support structure for solid oxide fuel cells, refractories, electric/electronic materials, aerospace vehicle re-entry heat shields and biomaterials for dental as well as orthopaedic implants by naming only a few. Multicellular ceramic bodies are usually made of ceramic phases such as mullite, cordierite, aluminum titanate or pure oxides such as silica, zirconia and alumina. What make alumina ceramics is excellent for the above functions are the intrinsic properties of alumina which are hard, wear resistant, excellent dielectric properties, resists strong acid and alkali attacks at elevated temperatures, good thermal conductivities, high strength and stiffness as well as biocompatible. In this work the processing technology leading to truly multicellular monolithic alumina ceramic bodies and their characterization are reported. Ceramic slip with 66 wt.% solid loading was found to be optimum as impregnant to the polyurethane foam template. Mullitic ceramic composite of alumina-sodium alumino disilicate-Leucite-like phases with bulk and true densities of 0.852 and 1.241 g cm{sup −3} respectively, pore linear density of ±35 cm{sup −1}, linear and bulk volume shrinkages of 7-16% and 32 vol.% were obtained. The compressive strength and elastic modulus of the bioceramics are ≈0.5-1.0 and ≈20 MPa respectively.

  5. Efficient adsorbents of nanoporous aluminosilicate monoliths for organic dyes from aqueous solution.

    PubMed

    El-Safty, Sherif A; Shahat, Ahmed; Awual, Md Rabiul

    2011-07-01

    Growing public awareness on the potential risk to humans of toxic chemicals in the environment has generated demand for new and improved methods for toxicity assessment and removal, rational means for health risk estimation. With the aim of controlling nanoscale adsorbents for functionality in molecular sieving of organic pollutants, we fabricated cubic Im3m mesocages with uniform entrance and large cavity pores of aluminosilicates as highly promising candidates for the colorimetric monitoring of organic dyes in an aqueous solution. However, a feasible control over engineering of three-dimensional (3D) mesopore cage structures with uniform entrance (~5 nm) and large cavity (~10 nm) allowed the development of nanoadsorbent membranes as a powerful tool for large-quantity and high-speed (in minutes) adsorption/removal of bulk molecules such as organic dyes. Incorporation of high aluminum contents (Si/Al=1) into 3D cubic Im3m cage mesoporous silica monoliths resulted in small, easy-to-use optical adsorbent strips. In such adsorption systems, natural surfaces of active acid sites of aluminosilicate strips strongly induced both physical adsorption of chemically responsive dyes and intraparticle diffusion into cubic Im3m mesocage monoliths. Results likewise indicated that although aluminosilicate strips with low Si/Al ratios exhibit distortion in pore ordering and decrease in surface area and pore volume, enhancement of both molecular converges and intraparticle diffusion onto the network surfaces and into the pore architectures of adsorbent membranes was achieved. Moreover, 3D mesopore cage adsorbents are reversible, offering potential for multiple adsorption assays.

  6. Silica Fillers for elastomer Reinforement

    SciTech Connect

    Kohls, D.J.; Schaefer, D.W.

    2012-09-10

    This article summarizes recent work on the structure of precipitated silica used in the reinforcement of elastomers. Silica has a unique morphology, consisting of multiple structural levels that can be controlled through processing. The ability to control and characterize the multiple structures of precipitated silica is an example of morphological engineering for reinforcement applications. In this summary of some recent research efforts using precipitated silica, small-angle scattering techniques are described and their usefulness for determining the morphology of silica in terms of primary particles, aggregates, and agglomerates are discussed. The structure of several different precipitated silica powders is shown as well as the mechanical properties of elastomers reinforced with these silica particles. The study of the mechanical properties of filled elastomer systems is a challenging and exciting topic for both fundamental science and industrial application. It is known that the addition of hard particulates to a soft elastomer matrix results in properties that do not follow a straightforward rule of mixtures. Research efforts in this area have shown that the properties of filled elastomers are influenced by the nature of both the filler and the matrix, as well as the interactions between them. Several articles have reviewed the influence of fillers like silica and carbon black on the reinforcement of elastomers. In general, the structure-property relationships developed for filled elastomers have evolved into the following major areas: Filler structure, hydrodynamic reinforcement, and interactions between fillers and elastomers.

  7. Interfacial engineering for silica nanocapsules.

    PubMed

    Wibowo, David; Hui, Yue; Middelberg, Anton P J; Zhao, Chun-Xia

    2016-10-01

    Silica nanocapsules have attracted significant interest due to their core-shell hierarchical structure. The core domain allows the encapsulation of various functional components such as drugs, fluorescent and magnetic nanoparticles for applications in drug delivery, imaging and sensing, and the silica shell with its unique properties including biocompatibility, chemical and physical stability, and surface-chemistry tailorability provides a protection layer for the encapsulated cargo. Therefore, significant effort has been directed to synthesize silica nanocapsules with engineered properties, including size, composition and surface functionality, for various applications. This review provides a comprehensive overview of emerging methods for the manufacture of silica nanocapsules, with a special emphasis on different interfacial engineering strategies. The review starts with an introduction of various manufacturing approaches of silica nanocapsules highlighting surface engineering of the core template nanomaterials (solid nanoparticles, liquid droplets, and gas bubbles) using chemicals or biomolecules which are able to direct nucleation and growth of silica at the boundary of two-phase interfaces (solid-liquid, liquid-liquid, and gas-liquid). Next, surface functionalization of silica nanocapsules is presented. Furthermore, strategies and challenges of encapsulating active molecules (pre-loading and post-loading approaches) in these capsular systems are critically discussed. Finally, applications of silica nanocapsules in controlled release, imaging, and theranostics are reviewed. PMID:27522646

  8. Biasable, Balanced, Fundamental Submillimeter Monolithic Membrane Mixer

    NASA Technical Reports Server (NTRS)

    Siegel, Peter; Schlecht, Erich; Mehdi, Imran; Gill, John; Velebir, James; Tsang, Raymond; Dengler, Robert; Lin, Robert

    2010-01-01

    This device is a biasable, submillimeter-wave, balanced mixer fabricated using JPL s monolithic membrane process a simplified version of planar membrane technology. The primary target application is instrumentation used for analysis of atmospheric constituents, pressure, temperature, winds, and other physical and chemical properties of the atmospheres of planets and comets. Other applications include high-sensitivity gas detection and analysis. This innovation uses a balanced configuration of two diodes allowing the radio frequency (RF) signal and local oscillator (LO) inputs to be separated. This removes the need for external diplexers that are inherently narrowband, bulky, and require mechanical tuning to change frequency. Additionally, this mixer uses DC bias-ability to improve its performance and versatility. In order to solve problems relating to circuit size, the GaAs membrane process was created. As much of the circuitry as possible is fabricated on-chip, making the circuit monolithic. The remainder of the circuitry is precision-machined into a waveguide block that holds the GaAs circuit. The most critical alignments are performed using micron-scale semiconductor technology, enabling wide bandwidth and high operating frequencies. The balanced mixer gets superior performance with less than 2 mW of LO power. This can be provided by a simple two-stage multiplier chain following an amplifier at around 90 GHz. Further, the diodes are arranged so that they can be biased. Biasing pushes the diodes closer to their switching voltage, so that less LO power is required to switch the diodes on and off. In the photo, the diodes are at the right end of the circuit. The LO comes from the waveguide at the right into a reduced-height section containing the diodes. Because the diodes are in series to the LO signal, they are both turned on and off simultaneously once per LO cycle. Conversely, the RF signal is picked up from the RF waveguide by the probe at the left, and flows

  9. Monolithic CMOS imaging x-ray spectrometers

    NASA Astrophysics Data System (ADS)

    Kenter, Almus; Kraft, Ralph; Gauron, Thomas; Murray, Stephen S.

    2014-07-01

    The Smithsonian Astrophysical Observatory (SAO) in collaboration with SRI/Sarnoff is developing monolithic CMOS detectors optimized for x-ray astronomy. The goal of this multi-year program is to produce CMOS x-ray imaging spectrometers that are Fano noise limited over the 0.1-10keV energy band while incorporating the many benefits of CMOS technology. These benefits include: low power consumption, radiation "hardness", high levels of integration, and very high read rates. Small format test devices from a previous wafer fabrication run (2011-2012) have recently been back-thinned and tested for response below 1keV. These devices perform as expected in regards to dark current, read noise, spectral response and Quantum Efficiency (QE). We demonstrate that running these devices at rates ~> 1Mpix/second eliminates the need for cooling as shot noise from any dark current is greatly mitigated. The test devices were fabricated on 15μm, high resistivity custom (~30kΩ-cm) epitaxial silicon and have a 16 by 192 pixel format. They incorporate 16μm pitch, 6 Transistor Pinned Photo Diode (6TPPD) pixels which have ~40μV/electron sensitivity and a highly parallel analog CDS signal chain. Newer, improved, lower noise detectors have just been fabricated (October 2013). These new detectors are fabricated on 9μm epitaxial silicon and have a 1k by 1k format. They incorporate similar 16μm pitch, 6TPPD pixels but have ~ 50% higher sensitivity and much (3×) lower read noise. These new detectors have undergone preliminary testing for functionality in Front Illuminated (FI) form and are presently being prepared for back thinning and packaging. Monolithic CMOS devices such as these, would be ideal candidate detectors for the focal planes of Solar, planetary and other space-borne x-ray astronomy missions. The high through-put, low noise and excellent low energy response, provide high dynamic range and good time resolution; bright, time varying x-ray features could be temporally and

  10. Synthesis and properties of Chitosan-silica hybrid aerogels

    SciTech Connect

    Ayers, Michael R.; Hunt, Arlon J.

    2001-06-01

    Chitosan, a polymer that is soluble in dilute aqueous acid, is derived from chitin, a natural polyglucosamide. Aquagels where the solid phase consists of both chitosan and silica can be easily prepared by using an acidic solution of chitosan to catalyze the hydrolysis and condensation of tetraethylorthosilicate. Gels with chitosan/TEOS mass ratios of 0.1-1.1 have been prepared by this method. Standard drying processes using CO{sub 2} give the corresponding aerogels. The amount of chitosan in the gel plays a role in the shrinkage of the aerogel during drying. Gels with the lowest chitosan/silica ratios show the most linear shrinkage, up to 24%, while those with the highest ratios show only a 7% linear shrinkage. Pyrolysis at 700 C under nitrogen produces a darkened aerogel due to the thermal decomposition of the chitosan, however, the aerogel retains its monolithic form. The pyrolyzed aerogels absorb slightly more infrared radiation in the 2-5 {micro}m region than the original aerogels. B.E.T. surface areas of these aerogels range from 470-750 m{sup 2}/g. Biocompatibility screening of this material shows a very high value for hemolysis, but a low value for cytotoxicity.

  11. "Gray Areas": Silica gels, amorphous silica and cryptocrystalline silica on fault surfaces

    NASA Astrophysics Data System (ADS)

    Rowe, C. D.; Kirkpatrick, J. D.; White, J. C.; Faber, C.; Caine, J. S.

    2012-12-01

    Silica gels, in the form of their solid-phase equivalents, are widely found in brittle fault zones and are commonly associated with mineral deposits. High- to moderate-velocity rotary friction experiments have produced silica gels on sliding surfaces coeval with dramatic slip weakening. In light of the latter, silica gel formation has been proposed as a potential mechanism of slip weakening during earthquakes in the shallow crust. However, low velocity sliding experiments have also produced significant amounts of amorphous material distributed throughout slipping layers, and dramatic weakening is not observed. Comparison of the products of laboratory experiments to geological examples is complicated by the diagenesis and lithification of silica gels. They may form hydrous and amorphous solids, hydrous crystalline solids, or dehydrate to quartz. In addition, the abundance and style of occurrence of these products in faults suggest that there are multiple origins for silica gels in faults. We review the mechanisms by which silica gels may form in fault zones and describe the solidification, crystallization and dehydration evolution of the silica. Analytical transmission electron microscope (TEM) observations of slip-surface silica deposits from the Corona Fault, San Francisco, the Dixie Valley Fault, Nevada, and the Olive Fault, Namibia typify the nano- to micro-structural evolution of the fault surface silica layers. We suggest criteria for identifying these materials in natural fault rocks. Some of these gels may form by comminution and hydrolization of silica-rich wall rocks, as has been observed in high-velocity experiments (Corona Fault). Others may form by depressurization and boiling of aqueous fluids, probably during fault valving (Olive Fault). Silica saturated hydrothermal fluids released during faulting may contribute in some cases (Dixie Valley Fault). Regardless of the mechanism of gel formation, the dramatic rheological weakening observed in friction

  12. Recyclable functionalization of silica with alcohols via dehydrogenative addition on hydrogen silsesquioxane.

    PubMed

    Moitra, Nirmalya; Kamei, Toshiyuki; Kanamori, Kazuyoshi; Nakanishi, Kazuki; Takeda, Kazuyuki; Shimada, Toyoshi

    2013-10-01

    Synthesis of class II hybrid silica materials requires the formation of covalent linkage between organic moieties and inorganic frameworks. The requirement that organosilylating agents be present to provide the organic part limits the synthesis of functional inorganic oxides, however, due to the water sensitivity and challenges concerning purification of the silylating agents. Synthesis of hybrid materials with stable molecules such as simple alcohols, rather than with these difficult silylating agents, may therefore provide a path to unprecedented functionality. Herein, we report the novel functionalization of silica with organic alcohols for the first time. Instead of using hydrolyzable organosilylating agents, we used stable organic alcohols with a Zn(II) catalyst to modify the surface of a recently discovered highly reactive macro-mesoporous hydrogen silsesquioxane (HSQ, HSiO1.5) monolith, which was then treated with water with the catalyst to form surface-functionalized silica. These materials were comprehensively characterized with FT-IR, Raman, solid-state NMR, fluorescence spectroscopy, thermal analysis, elemental analysis, scanning electron microscopy, and nitrogen adsorption-desorption measurements. The results obtained from these measurements reveal facile immobilization of organic moieties by dehydrogenative addition onto surface silane (Si-H) at room temperature with high loading and good tolerance of functional groups. The organic moieties can also be retrieved from the monoliths for recycling and reuse, which enables cost-effective and ecological use of the introduced catalytic/reactive surface functionality. Preservation of the reactivity of as-immobilized organic alcohols has been confirmed, moreover, by successfully performing copper-catalyzed azide-alkyne cycloaddition (CuAAC) "click" reactions on the immobilized silica surfaces. PMID:23977900

  13. Monolithic glass block lasercom terminal: hardware proof of concept and test results

    NASA Astrophysics Data System (ADS)

    Carlson, Robert T.; Drake, Marvin D.; Jaeger, Jerold L.

    1995-04-01

    We summarize a compact lasercom terminal implementation based on a previously described system concept, and report on measurements made on a prototype optical system built on internal MITRE funds. This paper discusses the fabrication and test of an innovative hardware proof-of-concept for an advanced satellite lasercom terminal with a ten-fold size, weight, and production cost reduction over current practice. We have built and tested a proof-of-concept of the optics portion of a full duplex `monolithic glass block' (MGB) lasercom terminal. The complete MGB optical system is only 6' X 4' X 0.5' and weighs less than a pound. A complete terminal which includes a 3 - 4 inch telescope and gimbal could be implemented for as little as 15 - 30 pounds. The optical system test results are reported. Our approach uses emerging technologies and a highly integrated system design, based on representative system requirements for satellite crosslinks. Technology evaluation and system trades led to a novel optics design for a lasercom terminal, based on thin film coatings and half-inch glass cubes. The emerging photonic technologies employed include liquid crystals for solid state switching, automatic gain control, and microradian alignment; multi-layer dielectric films for optical bandpass filters, dichroic separation, and polarization control; semiconductor lasers with microlens optics; and an original design where all the optics are realized in planar thin films incorporated on small glass substrates, nominally one-half inch in size. These glass cubes are permanently bonded together to form a monolithic ensemble. Hence, we have coined this implementation the monolithic glass block (MGB) approach. Fused silica is used throughout for reasons of superb radiation resistance and thermal stability. The thin film filters, switches, and polarizers perform all the necessary functions in collimated light. This approach is feasible because the optical paths have been dramatically reduced to

  14. Silaffins in Silica Biomineralization and Biomimetic Silica Precipitation

    PubMed Central

    Lechner, Carolin C.; Becker, Christian F. W.

    2015-01-01

    Biomineralization processes leading to complex solid structures of inorganic material in biological systems are constantly gaining attention in biotechnology and biomedical research. An outstanding example for biomineral morphogenesis is the formation of highly elaborate, nano-patterned silica shells by diatoms. Among the organic macromolecules that have been closely linked to the tightly controlled precipitation of silica in diatoms, silaffins play an extraordinary role. These peptides typically occur as complex posttranslationally modified variants and are directly involved in the silica deposition process in diatoms. However, even in vitro silaffin-based peptides alone, with and without posttranslational modifications, can efficiently mediate biomimetic silica precipitation leading to silica material with different properties as well as with encapsulated cargo molecules of a large size range. In this review, the biomineralization process of silica in diatoms is summarized with a specific focus on silaffins and their in vitro silica precipitation properties. Applications in the area of bio- and nanotechnology as well as in diagnostics and therapy are discussed. PMID:26295401

  15. The 30-GHz monolithic receive module

    NASA Technical Reports Server (NTRS)

    Sokolov, V.; Geddes, J.; Bauhahn, P.

    1983-01-01

    Key requirements for a 30 GHz GaAs monolithic receive module for spaceborne communication antenna feed array applications include an overall receive module noise figure of 5 dB, a 30 dB RF to IF gain with six levels of intermediate gain control, a five-bit phase shifter, and a maximum power consumption of 250 mW. The RF designs for each of the four submodules (low noise amplifier, some gain control, phase shifter, and RF to IF sub-module) are presented. Except for the phase shifter, high frequency, low noise FETs with sub-half micron gate lengths are employed in the submodules. For the gain control, a two stage dual gate FET amplifier is used. The phase shifter is of the passive switched line type and consists of 5-bits. It uses relatively large gate width FETs (with zero drain to source bias) as the switching elements. A 20 GHz local oscillator buffer amplifier, a FET compatible balanced mixer, and a 5-8 GHz IF amplifier constitute the RF/IF sub-module. Phase shifter fabrication using ion implantation and a self-aligned gate technique is described. Preliminary RF results obtained on such phase shifters are included.

  16. Solid oxide fuel cell having monolithic core

    DOEpatents

    Ackerman, John P.; Young, John E.

    1984-01-01

    A solid oxide fuel cell for electrochemically combining fuel and oxidant for generating galvanic output, wherein the cell core has an array of electrolyte and interconnect walls that are substantially devoid of any composite inert materials for support. Instead, the core is monolithic, where each electrolyte wall consists of thin layers of cathode and anode materials sandwiching a thin layer of electrolyte material therebetween, and each interconnect wall consists of thin layers of the cathode and anode materials sandwiching a thin layer of interconnect material therebetween. The electrolyte walls are arranged and backfolded between adjacent interconnect walls operable to define a plurality of core passageways alternately arranged where the inside faces thereof have only the anode material or only the cathode material exposed. Means direct the fuel to the anode-exposed core passageways and means direct the oxidant to the cathode-exposed core passageway; and means also direct the galvanic output to an exterior circuit. Each layer of the electrolyte and interconnect materials is of the order of 0.002-0.01 cm thick; and each layer of the cathode and anode materials is of the order of 0.002-0.05 cm thick.

  17. Solid oxide fuel cell having monolithic core

    DOEpatents

    Ackerman, J.P.; Young, J.E.

    1983-10-12

    A solid oxide fuel cell is described for electrochemically combining fuel and oxidant for generating galvanic output, wherein the cell core has an array of electrolyte and interconnect walls that are substantially devoid of any composite inert materials for support. Instead, the core is monolithic, where each electrolyte wall consists of thin layers of cathode and anode materials sandwiching a thin layer of electrolyte material therebetween. The electrolyte walls are arranged and backfolded between adjacent interconnect walls operable to define a plurality of core passageways alternately arranged where the inside faces thereof have only the anode material or only the cathode material exposed. Means direct the fuel to the anode-exposed core passageways and means direct the oxidant to the anode-exposed core passageways and means direct the oxidant to the cathode-exposed core passageway; and means also direct the galvanic output to an exterior circuit. Each layer of the electrolyte and interconnect materials is of the order of 0.002 to 0.01 cm thick; and each layer of the cathode and anode materials is of the order of 0.002 to 0.05 cm thick.

  18. Neutron spectrometry with a monolithic silicon telescope.

    PubMed

    Agosteo, S; D'Angelo, G; Fazzi, A; Para, A Foglio; Pola, A; Zotto, P

    2007-01-01

    A neutron spectrometer was set-up by coupling a polyethylene converter with a monolithic silicon telescope, consisting of a DeltaE and an E stage-detector (about 2 and 500 microm thick, respectively). The detection system was irradiated with monoenergetic neutrons at INFN-Laboratori Nazionali di Legnaro (Legnaro, Italy). The maximum detectable energy, imposed by the thickness of the E stage, is about 8 MeV for the present detector. The scatter plots of the energy deposited in the two stages were acquired using two independent electronic chains. The distributions of the recoil-protons are well-discriminated from those due to secondary electrons for energies above 0.350 MeV. The experimental spectra of the recoil-protons were compared with the results of Monte Carlo simulations using the FLUKA code. An analytical model that takes into account the geometrical structure of the silicon telescope was developed, validated and implemented in an unfolding code. The capability of reproducing continuous neutron spectra was investigated by irradiating the detector with neutrons from a thick beryllium target bombarded with protons. The measured spectra were compared with data taken from the literature. Satisfactory agreement was found. PMID:17522037

  19. Solid oxide fuel cell with monolithic core

    DOEpatents

    McPheeters, Charles C.; Mrazek, Franklin C.

    1988-01-01

    A solid oxide fuel cell in which fuel and oxidant gases undergo an electrochemical reaction to produce an electrical output includes a monolithic core comprised of a corrugated conductive sheet disposed between upper and lower generally flat sheets. The corrugated sheet includes a plurality of spaced, parallel, elongated slots which form a series of closed, linear, first upper and second lower gas flow channels with the upper and lower sheets within which a fuel gas and an oxidant gas respectively flow. Facing ends of the fuel cell are generally V-shaped and provide for fuel and oxidant gas inlet and outlet flow, respectively, and include inlet and outlet gas flow channels which are continuous with the aforementioned upper fuel gas and lower oxidant gas flow channels. The upper and lower flat sheets and the intermediate corrugated sheet are preferably comprised of ceramic materials and are securely coupled together such as by assembly in the green state and sintering together during firing at high temperatures. A potential difference across the fuel cell, or across a stacked array of similar fuel cells, is generated when an oxidant gas such as air and a fuel such as hydrogen gas is directed through the fuel cell at high temperatures, e.g., between 700.degree. C. and 1100.degree. C.

  20. Solid oxide fuel cell with monolithic core

    DOEpatents

    McPheeters, C.C.; Mrazek, F.C.

    1988-08-02

    A solid oxide fuel cell in which fuel and oxidant gases undergo an electrochemical reaction to produce an electrical output includes a monolithic core comprised of a corrugated conductive sheet disposed between upper and lower generally flat sheets. The corrugated sheet includes a plurality of spaced, parallel, elongated slots which form a series of closed, linear, first upper and second lower gas flow channels with the upper and lower sheets within which a fuel gas and an oxidant gas respectively flow. Facing ends of the fuel cell are generally V-shaped and provide for fuel and oxidant gas inlet and outlet flow, respectively, and include inlet and outlet gas flow channels which are continuous with the aforementioned upper fuel gas and lower oxidant gas flow channels. The upper and lower flat sheets and the intermediate corrugated sheet are preferably comprised of ceramic materials and are securely coupled together such as by assembly in the green state and sintering together during firing at high temperatures. A potential difference across the fuel cell, or across a stacked array of similar fuel cells, is generated when an oxidant gas such as air and a fuel such as hydrogen gas is directed through the fuel cell at high temperatures, e.g., between 700 C and 1,100 C. 8 figs.

  1. Monolithic integrated-optic TDLAS sensors

    NASA Astrophysics Data System (ADS)

    Frish, Michael B.; Scherer, David R.; Wainner, Richard T.; Allen, Mark G.; Shankar, Raji; Loncar, Marko

    2012-06-01

    We are developing prototype chip-scale low-power integrated-optic gas-phase chemical sensors based on infrared Tunable Diode Laser Absorption Spectroscopy (TDLAS). TDLAS is able to sense many gas phase chemicals with high sensitivity and selectivity. Using semiconductor fabrication and assembly techniques, the low-cost integrated optic TDLAS technology will permit mass production of sensors that have wide ranging industrial, medical, environmental, and consumer applications. Novel gas sensing elements using low-loss resonant photonic crystal cavities or waveguides will permit monolithic integration of a laser source, sampling elements, and detector on a semiconductor materials system substrate. Practical challenges to fabricating these devices include: a) selecting and designing the high-Q micro-resonator sensing element appropriate for the selected analyte; and b) device thermal management, especially stabilizing laser temperature with the precision needed for sensitive spectroscopic detection. In this paper, we analyze the expected sensitivity of micro-resonator-based structures for chemical sensing, and demonstrate a novel approach for exploiting laser waste heat to stabilize the laser temperature.

  2. Monolithic supports with unique geometries and enhanced mass transfer.

    SciTech Connect

    Stuecker, John Nicholas; Ferrizz, Robert Matthew; Cesarano, Joseph, III; Miller, James Edward

    2004-01-01

    The catalytic combustion of natural gas has been the topic of much research over the past decade. Interest in this technology results from a desire to decrease or eliminate the emissions of harmful nitrogen oxides (NOX) from gas turbine power plants. A low-pressure drop catalyst support, such as a ceramic monolith, is ideal for this high-temperature, high-flow application. A drawback to the traditional honeycomb monoliths under these operating conditions is poor mass transfer to the catalyst surface in the straight-through channels. 'Robocasting' is a unique process developed at Sandia National Laboratories that can be used to manufacture ceramic monoliths with alternative 3-dimensional geometries, providing tortuous pathways to increase mass transfer while maintaining low pressure drops. This report details the mass transfer effects for novel 3-dimensional robocast monoliths, traditional honeycomb-type monoliths, and ceramic foams. The mass transfer limit is experimentally determined using the probe reaction of CO oxidation over a Pt / {gamma}-Al{sub 2}O{sub 3} catalyst, and the pressure drop is measured for each monolith sample. Conversion versus temperature data is analyzed quantitatively using well-known dimensionless mass transfer parameters. The results show that, relative to the honeycomb monolith support, considerable improvement in mass transfer efficiency is observed for robocast samples synthesized using an FCC-like geometry of alternating rods. Also, there is clearly a trade-off between enhanced mass transfer and increased pressure drop, which can be optimized depending on the particular demands of a given application.

  3. Progress on femtosecond laser-based system-materials: three-dimensional monolithic electrostatic micro-actuator for optomechanics

    NASA Astrophysics Data System (ADS)

    Yang, Tao; Bellouard, Yves

    2016-03-01

    Femtosecond laser-dielectric interaction in a three-dimensional (3D) manner defines a capable platform for integrated 3D micro-devices fabricated out of a single piece of system-material. Here, we add a new function to femtosecond laserbased single monolith in amorphous fused silica by demonstrating a transparent 3D micro-actuator using non-ablative femtosecond laser micromachining with subsequent chemical etching. The actuation principle is based on dielectrophoresis (DEP), defined as the unbalanced electrostatic action on dielectrics, due to an induced dipole moment under a non-uniform electric field. An analytical model of this actuation scheme is proposed, which is capable of performance prediction, design parameter optimization and motion instability analysis. Furthermore, the static and dynamic performances are experimentally characterized using optical measurement methods. An actuation range of 30 μm is well attainable; resonances and the settling time in transient responses are measured; the quality factor and the bandwidth for the primary vertical resonance are also evaluated. Experimental results are in good consistence with theoretical analyses. The proposed actuation principle suppresses the need for electrodes on the mobile, non-conductive component and is particularly interesting for moving transparent elements. Thanks to the flexibility of femtosecond laser manufacturing process, this actuation scheme can be integrated in other functionalities within monolithic transparent Micro-Electro-Mechanical Systems (MEMS) for applications like resonators, adaptive lenses and integrated photonics circuits.

  4. Application of a low impedance contactless conductometric detector for the determination of inorganic cations in capillary monolithic column chromatography.

    PubMed

    Shen, Dazhong; Li, Dongdong; Yang, Xiuwen; Zhu, Yan; Dong, Jianfeng; Kang, Qi

    2011-03-15

    Poly(glycidyl methacrylate) cation exchange monolithic column was prepared in fused-silica capillaries of 320 μm i.d. by thermally initiated radical polymerization and utilized in capillary ion chromatography. With 15 mM methanesulfonic acid as the mobile phase, the separations of a mixture of inorganic cations (Li(+), Na(+), NH(4)(+), K(+)) was tested by using a capacitively coupled contactless conductivity detector (C(4)D) and a low impedance C(4)D (LIC(4)D). The LIC(4)D is the series combination of a C(4)D and a quartz crystal resonator. At the resonant frequency of the series combination, the capacitor impedance from capillary wall was offset by the inductance impedance from the quartz crystal resonator. A minimum impedance was obtained in the impedance-frequency curve of the combination. The responses of the C(4)D and LIC(4)D were analyzed based on an equivalent circuit model. It was shown that the sensitivity of the C(4)D to the change in analyte concentration is rather poor due to the high ratio of the impedance from the capillary wall capacitor to the solution impedance. The LIC(4)D has the similar sensitivity as a contact conductivity detector but a much smaller cell volume. The on-column detection model was realized by LiC(4)D without preparation of optical detection window in monolithic column.

  5. Capillary electrochromatography-atmospheric pressure ionization mass spectrometry of pesticides using a surfactant-bound monolithic column

    PubMed Central

    Gu, Congying; Shamsi, Shahab A.

    2011-01-01

    A surfactant bound poly (11-acrylaminoundecanoic acid-ethylene dimethacrylate) (AAUA-EDMA) monolithic column was simply prepared by in-situ co-polymerization of AAUA and EDMA with 1-propanol, 1,4-butanediol and water as porogens in 100 µm id fused silica capillary in one step. This column was used in capillary electrochromatography (CEC)-atmospheric pressure photoionization (APPI)-mass spectrometry system for separation and detection of N-methylcarbamates (NMCs) pesticides. Numerous parameters are optimized for CEC-APPI-MS. After evaluation of the mobile phase composition, sheath liquid composition and the monolithic capillary outlet position, a fractional factorial design (FFD) was selected as a screening procedure to identify factors of ionization source parameters, such as sheath liquid flow rate, drying gas flow rate, drying gas temperature, nebulizing gas pressure, vaporizer temperature, and capillary voltage, which significantly influence APPI-MS sensitivity. A face-centered central composite design (CCD) was further utilized to optimize the most significant parameters and predict the best sensitivity. Under optimized conditions signal-to-noise ratios (S/N) around 78 were achieved for an injection of 100 ng/mL of each pesticide. Finally, this CEC-APPI-MS method was successfully applied to the analysis of nine NMCs in spiked apple juice sample after solid phase extraction with recoveries in the range of 65 to 109%. PMID:20349511

  6. Advanced Gasification Mercury/Trace Metal Control with Monolith Traps

    SciTech Connect

    Musich, Mark; Swanson, Michael; Dunham, Grant; Stanislowski, Joshua

    2010-10-05

    Two Corning monoliths and a non-carbon-based material have been identified as potential additives for mercury capture in syngas at temperatures above 400°F and pressure of 600 psig. A new Corning monolith formulation, GR-F1-2189, described as an active sample appeared to be the best monolith tested to date. The Corning SR Liquid monolith concept continues to be a strong candidate for mercury capture. Both monolith types allowed mercury reduction to below 5-μg/m{sup 3} (~5 ppb), a current U.S. Department of Energy (DOE) goal for trace metal control. Preparation methods for formulating the SR Liquid monolith impacted the ability of the monolith to capture mercury. The Energy & Environmental Research Center (EERC)-prepared Noncarbon Sorbents 1 and 2 appeared to offer potential for sustained and significant reduction of mercury concentration in the simulated fuel gas. The Noncarbon Sorbent 1 allowed sustained mercury reduction to below 5-μg/m{sup 3} (~5 ppb). The non-carbon-based sorbent appeared to offer the potential for regeneration, that is, desorption of mercury by temperature swing (using nitrogen and steam at temperatures above where adsorption takes place). A Corning cordierite monolith treated with a Group IB metal offered limited potential as a mercury sorbent. However, a Corning carbon-based monolith containing prereduced metallic species similar to those found on the noncarbon sorbents did not exhibit significant or sustained mercury reduction. EERC sorbents prepared with Group IB and IIB selenide appeared to have some promise for mercury capture. Unfortunately, these sorbents also released Se, as was evidenced by the measurement of H2Se in the effluent gas. All sorbents tested with arsine or hydrogen selenide, including Corning monoliths and the Group IB and IIB metal-based materials, showed an ability to capture arsine or hydrogen selenide at 400°F and 600 psig. Based on current testing, the noncarbon metal-based sorbents appear to be the most

  7. ADVANCED GASIFICATION MERCURY/TRACE METAL CONTROL WITH MONOLITH TRAPS

    SciTech Connect

    Mark A. Musich; Michael L. Swanson; Grant E. Dunham; Joshua J. Stanislowski

    2010-07-31

    Two Corning monoliths and a non-carbon-based material have been identified as potential additives for mercury capture in syngas at temperatures above 400°F and pressure of 600 psig. A new Corning monolith formulation, GR-F1-2189, described as an active sample appeared to be the best monolith tested to date. The Corning SR Liquid monolith concept continues to be a strong candidate for mercury capture. Both monolith types allowed mercury reduction to below 5-μg/m3 (~5 ppb), a current U.S. Department of Energy (DOE) goal for trace metal control. Preparation methods for formulating the SR Liquid monolith impacted the ability of the monolith to capture mercury. The Energy & Environmental Research Center (EERC)-prepared Noncarbon Sorbents 1 and 2 appeared to offer potential for sustained and significant reduction of mercury concentration in the simulated fuel gas. The Noncarbon Sorbent 1 allowed sustained mercury reduction to below 5-μg/m3 (~5 ppb). The non-carbon-based sorbent appeared to offer the potential for regeneration, that is, desorption of mercury by temperature swing (using nitrogen and steam at temperatures above where adsorption takes place). A Corning cordierite monolith treated with a Group IB metal offered limited potential as a mercury sorbent. However, a Corning carbon-based monolith containing prereduced metallic species similar to those found on the noncarbon sorbents did not exhibit significant or sustained mercury reduction. EERC sorbents prepared with Group IB and IIB selenide appeared to have some promise for mercury capture. Unfortunately, these sorbents also released Se, as was evidenced by the measurement of H2Se in the effluent gas. All sorbents tested with arsine or hydrogen selenide, including Corning monoliths and the Group IB and IIB metal-based materials, showed an ability to capture arsine or hydrogen selenide at 400°F and 600 psig. Based on current testing, the noncarbon metal-based sorbents appear to be the most effective arsine

  8. Edge chipping and flexural resistance of monolithic ceramics☆

    PubMed Central

    Zhang, Yu; Lee, James J.-W.; Srikanth, Ramanathan; Lawn, Brian R.

    2014-01-01

    Objective Test the hypothesis that monolithic ceramics can be developed with combined esthetics and superior fracture resistance to circumvent processing and performance drawbacks of traditional all-ceramic crowns and fixed-dental-prostheses consisting of a hard and strong core with an esthetic porcelain veneer. Specifically, to demonstrate that monolithic prostheses can be produced with a much reduced susceptibility to fracture. Methods Protocols were applied for quantifying resistance to chipping as well as resistance to flexural failure in two classes of dental ceramic, microstructurally-modified zirconias and lithium disilicate glass–ceramics. A sharp indenter was used to induce chips near the edges of flat-layer specimens, and the results compared with predictions from a critical load equation. The critical loads required to produce cementation surface failure in monolithic specimens bonded to dentin were computed from established flexural strength relations and the predictions validated with experimental data. Results Monolithic zirconias have superior chipping and flexural fracture resistance relative to their veneered counterparts. While they have superior esthetics, glass–ceramics exhibit lower strength but higher chip fracture resistance relative to porcelain-veneered zirconias. Significance The study suggests a promising future for new and improved monolithic ceramic restorations, with combined durability and acceptable esthetics. PMID:24139756

  9. Thermoresponsive ketoprofen-imprinted monolith prepared in ionic liquid.

    PubMed

    Sun, Xuan; Zhao, Chun-Yan; Wang, Xian-Hua; Huang, Yan-Ping; Liu, Zhao-Sheng

    2014-09-01

    A thermoresponsive imprinted monolith with the ability of molecular recognition for ketoprofen was prepared for the first time. The smart monolith was synthesized in a stainless steel column using acrylamide (AAm) and 2-acrylamide-2-methyl propanesulfonic acid (AMPS) as functional monomers, which can form interpolymer complexation to restrict access of the analyte to the imprinted networks at low temperatures. To avoid a high back pressure of the column derived from neat dimethyl sulfoxide (DMSO) as a porogenic solvent that is needed to solve polar AMPS, an ionic liquid, [BMIM]BF4, was introduced into the pre-polymerization mixture. The molecular recognition ability towards ketoprofen of the resulting thermoresponsive molecularly imprinted polymer (MIP) monolith displayed significant dependence on temperature compared with a non-imprinted column (NIP), and the greatest imprinting factor was achieved at the transition temperature of 35 °C (above 10). Furthermore, the number of binding sites of the smart MIP monolith at 35 °C was about 76 times as large as that at 25 °C. In addition, Freundlich analyses indicated that the thermoresponsive MIP monolith had homogeneous affinity sites at both 25 and 35 °C with heterogeneity index 0.9251 and 0.9851, respectively.

  10. Continuous vs. discrete models of nonadiabatic monolith catalysts

    SciTech Connect

    Groppi, G.; Tronconi, E.

    1996-08-01

    Monolith catalysts are widely applied for clean up of waste gases [catalytic mufflers, volatile organic compound (VOC) incinerators, reactors for selective catalytic reduction (SCR) of NO{sub x} by NH{sub 3}] in view of their unique combination of low-pressure drops and high gas-solid interfacial areas. The crucial point in continuous heat-transfer models is the evaluation of the effective thermal conductivity coefficients, which are functions both of the physical properties of the two phases and of the monolith geometry. In this work a novel expression for calculation of the radial effective conductivity is derived. The physical consistency of the steady-state continuous model implementing such an expression is then analyzed by comparison with a discrete monolith model. In spite of the just-mentioned limitations, discrete models have been partially validated in the literature against experimental temperature profiles in heated monoliths; thus, they can be regarded as a standard in evaluating the adequacy of the continuum approach. The reference problem of pure heat transfer with constant temperature of the external monolith wall is investigated for these purposes.

  11. V-band monolithic two stage HEMT amplifiers

    NASA Astrophysics Data System (ADS)

    Aust, M.; Yonaki, J.; Nakano, K.; Berenz, J.; Dow, G.

    Two different types of HEMT (high-electron-mobility transistor) monolithic low-noise amplifiers (LNAs) using AlGaAs/GaAs and pseudomorphic InGaAs/GaAs materials have been developed and have demonstrated excellent performance at 60 GHz. These monolithic LNAs have achieved noise figures of 5 dB, as well as associated gains of 11 dB. These two-stage circuits both utilize 0.2- x 60-micron HEMT devices for both bandpass and low-pass circuit topologies. Noise figures as low as 4.5 dB have been observed for single-stage MMIC- (monolithic-microwave-integrated-circuit) implemented LNAs, and gains in excess of 20 dB have been observed for three-stage versions of this amplifier with a 5-dB noise figure in the V band. This result represents the state-of-the art monolithic HEMT amplifier performance for AlGaAs and pseudomorphic InGaAs materials. This MMIC amplifier can occupy about less than one-third the size of existing MIC hybrid V-band LNAs. This represents a significant size reduction and cost saving due to repeatable circuit performance with monolithic technology. The chip sizes are both 1.6 x 2.7 mm for these two-stage amplifiers.

  12. New Graphene Form of Nanoporous Monolith for Excellent Energy Storage.

    PubMed

    Bi, Hui; Lin, Tianquan; Xu, Feng; Tang, Yufeng; Liu, Zhanqiang; Huang, Fuqiang

    2016-01-13

    Extraordinary tubular graphene cellular material of a tetrahedrally connected covalent structure was very recently discovered as a new supermaterial with ultralight, ultrastiff, superelastic, and excellent conductive characteristics, but no high specific surface area will keep it from any next-generation energy storage applications. Herein, we prepare another new graphene monolith of mesoporous graphene-filled tubes instead of hollow tubes in the reported cellular structure. This graphene nanoporous monolith is also composed of covalently bonded carbon network possessing high specific surface area of ∼1590 m(2) g(-1) and electrical conductivity of ∼32 S cm(-1), superior to graphene aerogels and porous graphene forms self-assembled by graphene oxide. This 3D graphene monolith can support over 10 000 times its own weight, significantly superior to CNT and graphene cellular materials with a similar density. Furthermore, pseudocapacitance-active functional groups are introduced into the new nanoporous graphene monolith as an electrode material in electrochemical capacitors. Surprisingly, the electrode of 3D mesoporous graphene has a specific capacitance of 303 F g(-1) and maintains over 98% retention after 10 000 cycles, belonging to the list for the best carbon-based active materials. The macroscopic mesoporous graphene monolith suggests the great potential as an electrode for supercapacitors in energy storage areas.

  13. Preparation and characterization of poly(triallyl isocyanurate-co-trimethylolpropane triacrylate) monolith and its applications in the separation of small molecules by liquid chromatography.

    PubMed

    Zhong, Jing; Hao, Mengbei; Li, Ruo; Bai, Ligai; Yang, Gengliang

    2014-03-14

    A new polymeric monolith was prepared in stainless-steel column and fused-silica capillary, respectively, by atom transfer radical polymerization technique. In the polymerization, triallyl isocyanurate (TAIC) was used as the functional monomer; trimethylolpropane triacrylate (TMPTA) as the crosslinking agent; polyethylene glycol 200 and 1,2-propanediol as the co-porogens; carbon tetrachloride as the initiator and ferrous chloride as the catalyst. The conditions of polymerization were optimized. Morphology of the prepared poly(TAIC-co-TMPTA) monolith was investigated by scanning electron microscopy; pore properties were assayed by mercury porosimetry and nitrogen adsorption. The characterization indicated that the prepared reversed-phase monolith possessed uniform structure, good permeability and mechanical stability. The column was used as the stationary phase of reversed phase high performance liquid chromatography (RP-HPLC) and capillary liquid chromatography (CLC) to separate the mixture of aromatic compounds. The new column performed around 125,000 theoretical plates per meter. The column showed good reproducibility: the relative standard deviation values of the retention factor values for aromatic compounds were less than 1.52% (n=7, column-to-column).

  14. High-Throughput and Low-Cost Analysis of Trace Volatile Phthalates in Seafood by Online Coupling of Monolithic Capillary Adsorbent with GC-MS.

    PubMed

    Insuan, Wimonrut; Khawmodjod, Phatchara; Whitlow, Harry J; Soonthondecha, Peerapong; Malem, Fairda; Chienthavorn, Orapin

    2016-04-27

    A simple, sensitive, and high-throughput method was developed for the determination of six volatile phthalate esters-dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), benzylbutyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DnOP)-in seafood samples by using monolith adsorbent in a capillary coupled to a gas chromatography-mass spectrometry (GC-MS) system. The freeze-dried samples were subjected to an ultrasonication with hexane, followed by vortex mixing. The liquid extract was quantitatively determined by a direct application to an online silica monolith capillary adsorbent coupled with a gas chromatograph with mass spectrometric detection. Method validation in seafood matrix gave recoveries of 72.8-85.4% and a detection limit of 6.8-10.0 ng g(-1) for bivalve samples. Reusability of the monolith capillary for trapping coextracted matrix was up to six times, allowing high-throughput analysis at the parts per billion level. When compared with the Food and Environment Research Agency (FERA) method, no significant difference in the result was observed, confirming the method was valid and applicable for the routine analysis of phthalates in seafood samples for food and environmental laboratories. PMID:27082024

  15. Preparation and characterization of poly(triallyl isocyanurate-co-trimethylolpropane triacrylate) monolith and its applications in the separation of small molecules by liquid chromatography.

    PubMed

    Zhong, Jing; Hao, Mengbei; Li, Ruo; Bai, Ligai; Yang, Gengliang

    2014-03-14

    A new polymeric monolith was prepared in stainless-steel column and fused-silica capillary, respectively, by atom transfer radical polymerization technique. In the polymerization, triallyl isocyanurate (TAIC) was used as the functional monomer; trimethylolpropane triacrylate (TMPTA) as the crosslinking agent; polyethylene glycol 200 and 1,2-propanediol as the co-porogens; carbon tetrachloride as the initiator and ferrous chloride as the catalyst. The conditions of polymerization were optimized. Morphology of the prepared poly(TAIC-co-TMPTA) monolith was investigated by scanning electron microscopy; pore properties were assayed by mercury porosimetry and nitrogen adsorption. The characterization indicated that the prepared reversed-phase monolith possessed uniform structure, good permeability and mechanical stability. The column was used as the stationary phase of reversed phase high performance liquid chromatography (RP-HPLC) and capillary liquid chromatography (CLC) to separate the mixture of aromatic compounds. The new column performed around 125,000 theoretical plates per meter. The column showed good reproducibility: the relative standard deviation values of the retention factor values for aromatic compounds were less than 1.52% (n=7, column-to-column). PMID:24556171

  16. High-Throughput and Low-Cost Analysis of Trace Volatile Phthalates in Seafood by Online Coupling of Monolithic Capillary Adsorbent with GC-MS.

    PubMed

    Insuan, Wimonrut; Khawmodjod, Phatchara; Whitlow, Harry J; Soonthondecha, Peerapong; Malem, Fairda; Chienthavorn, Orapin

    2016-04-27

    A simple, sensitive, and high-throughput method was developed for the determination of six volatile phthalate esters-dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), benzylbutyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DnOP)-in seafood samples by using monolith adsorbent in a capillary coupled to a gas chromatography-mass spectrometry (GC-MS) system. The freeze-dried samples were subjected to an ultrasonication with hexane, followed by vortex mixing. The liquid extract was quantitatively determined by a direct application to an online silica monolith capillary adsorbent coupled with a gas chromatograph with mass spectrometric detection. Method validation in seafood matrix gave recoveries of 72.8-85.4% and a detection limit of 6.8-10.0 ng g(-1) for bivalve samples. Reusability of the monolith capillary for trapping coextracted matrix was up to six times, allowing high-throughput analysis at the parts per billion level. When compared with the Food and Environment Research Agency (FERA) method, no significant difference in the result was observed, confirming the method was valid and applicable for the routine analysis of phthalates in seafood samples for food and environmental laboratories.

  17. Silica/Polymer and Silica/Polymer/Fiber Composite Aerogels

    NASA Technical Reports Server (NTRS)

    Ou, Danny; Stepanian, Christopher J.; Hu, Xiangjun

    2010-01-01

    Aerogels that consist, variously, of neat silica/polymer alloys and silica/polymer alloy matrices reinforced with fibers have been developed as materials for flexible thermal-insulation blankets. In comparison with prior aerogel blankets, these aerogel blankets are more durable and less dusty. These blankets are also better able to resist and recover from compression . an important advantage in that maintenance of thickness is essential to maintenance of high thermal-insulation performance. These blankets are especially suitable as core materials for vacuum- insulated panels and vacuum-insulated boxes of advanced, nearly seamless design. (Inasmuch as heat leakage at seams is much greater than heat leakage elsewhere through such structures, advanced designs for high insulation performance should provide for minimization of the sizes and numbers of seams.) A silica/polymer aerogel of the present type could be characterized, somewhat more precisely, as consisting of multiply bonded, linear polymer reinforcements within a silica aerogel matrix. Thus far, several different polymethacrylates (PMAs) have been incorporated into aerogel networks to increase resistance to crushing and to improve other mechanical properties while minimally affecting thermal conductivity and density. The polymethacrylate phases are strongly linked into the silica aerogel networks in these materials. Unlike in other organic/inorganic blended aerogels, the inorganic and organic phases are chemically bonded to each other, by both covalent and hydrogen bonds. In the process for making a silica/polymer alloy aerogel, the covalent bonds are introduced by prepolymerization of the methacrylate monomer with trimethoxysilylpropylmethacrylate, which serves as a phase cross-linker in that it contains both organic and inorganic monomer functional groups and hence acts as a connector between the organic and inorganic phases. Hydrogen bonds are formed between the silanol groups of the inorganic phase and the

  18. Preparation of low flow-resistant methacrylate-based monolithic stationary phases of different hydrophobicity and the application to rapid reversed-phase liquid chromatographic separation of alkylbenzenes at high flow rate and elevated temperature.

    PubMed

    Ueki, Yuji; Umemura, Tomonari; Iwashita, Yoshikazu; Odake, Tamao; Haraguchi, Hiroki; Tsunoda, Kin-ichi

    2006-02-17

    Low flow-resistant alkyl methacrylate-based monolithic stationary phases of different hydrophobicity were constructed for reversed-phase capillary liquid chromatography by thermally initiated radical polymerization of respective methacrylate ester monomer with different alkyl chain (C2, C4, C6, C12, C18) and ethylene glycol dimethacrylate (EDMA) in a 250 microm i.d. fused silica capillary. The hydrophobicity was basically controlled by changing the length and/or the density of the alkyl-chain, while the composition and the ratio of porogenic solvent were adjusted to obtain highly permeable rigid monoliths with adequate column efficiency. Among the prepared monolithic stationary phases, C18-methacrylate monoliths polymerized from a binary porogenic solvent of isoamyl alcohol and 1,4-buthandiol exhibited the most promising performance in terms of hydraulic resistance and column efficiency. The pressure drops of 20-cm long monolithic columns were below approximately 0.4 MPa at a normal linear velocity of 1mm/s (a flow rate of 3 microL/min), and the numbers of theoretical plates for alkylbenzenes mostly exceeded 3000 plates/20 cm. The produced monolithic columns had good mechanical strength for high pressure and temperature, and could be properly operated even at a temperature of 80 degrees C and at a pressure of at least 33 MPa. At 80 degrees C, the theoretical plate numbers reached 6000 plates/20 cm because of the enhanced mass transfer. Due to the novel hydraulic resistance and mechanical strength, the separation time could be reduced 120-fold simply by raising the flow rate and column temperature.

  19. GaAs monolithic R.F. modules for SARSAT distress beacons

    NASA Technical Reports Server (NTRS)

    Cauley, Michael A.

    1991-01-01

    Monolithic GaAs UHF components for use in SARSAT Emergency Distress beacons are under development by Microwave Monolithics, Inc., Simi Valley, CA. The components include a bi-phase modulator, driver amplifier, and a 5 watt power amplifier.

  20. Monolithic Solid Oxide Fuel Cell development

    NASA Technical Reports Server (NTRS)

    Myles, K. M.; Mcpheeters, C. C.

    1989-01-01

    The Monolithic Solid Oxide Fuel Cell (MSOFC) is an oxide-ceramic structure in which appropriate electronic and ionic conductors are fabricated in a honeycomb shape similar to a block of corrugated paperboard. These electronic and ionic conductors are arranged to provide short conduction paths to minimize resistive losses. The power density achievable with the MSOFC is expected to be about 8 kW/kg or 4 kW/L, at fuel efficienceis over 50 percent, because of small cell size and low resistive losses in the materials. The MSOFC operates in the range of 700 to 1000 C, at which temperatures rapid reform of hydrocarbon fuels is expected within the nickel-YSZ fuel channels. Tape casting and hot roll calendering are used to fabricate the MSOFC structure. The performance of the MSOFC has improved significantly during the course of development. The limitation of this system, based on materials resistance alone without interfacial resistances, is 0.093 ohm-sq cm area-specific resistance (ASR). The current typical performance of MSOFC single cells is characterized by ASRs of about 0.4 to 0.5 ohm-sq cm. With further development the ASR is expected to be reduced below 0.2 ohm-sq cm, which will result in power levels greater than 1.4 W/sq cm. The feasibility of the MSOFC concept was proven, and the performance was dramatically improved. The differences in thermal expansion coefficients and firing shrinkages among the fuel cell materials were minimized. As a result of good matching of these properties, the MSOFC structure was successfully fabricated with few defects, and the system shows excellent promise for development into a practical power source.

  1. Facilitated fabrication of high strength silica aerogels using cellulose nanofibrils as scaffold.

    PubMed

    Fu, Jingjing; Wang, Siqun; He, Chunxia; Lu, Zexiang; Huang, Jingda; Chen, Zhilin

    2016-08-20

    Monolithic cellulose nanofibrils (CNF)-silica composite aerogels were successfully prepared by immersing CNF aerogels into a silica solution in a two-step sol-gel process (initial hydrolysis of tetraethyl orthosilicate (TEOS) followed by condensation of silica particles). Aerogels were characterized by SEM, BET surface area test, bulk density and silica content analysis, FTIR spectroscopy, and compression test. The form of SiO2 existing in the composite aerogel was the spherical individual particles coated on CNF fibrils. The pH value of condensation solution was found to have great influence on the properties of the composite aerogels. By varying the pH value of condensation atmosphere from 8 to 12, the bulk densities of composite aerogels were able to be linearly increased from 0.059gcm(-3) to 0.29gcm(-3),and the silica content in the matrix sharply jumped from 3wt% to 79wt%. The porosities of the aerogels remained very high, between 85 and 96%, and the surface area of the composite aerogel reached up to 700.1m(2)g(-1). The compression properties of the composite aerogel improved greatly compared with those of the silica aerogel, about 8-30 times higher. Moreover, the compressive strength of the composite aerogel prepared in this work greatly exceeded the conventional insulation materials found in the recent commercial market, and without substantial increases in thermal conductivity. Hence, the findings of this research offer a promising application for composite aerogels and give a theoretical basis for developing new advanced materials. PMID:27178912

  2. Monolithic fuel cell based power source for burst power generation

    NASA Astrophysics Data System (ADS)

    Fee, D. C.; Blackburn, P. E.; Busch, D. E.; Dees, D. W.; Dusek, J.; Easler, T. E.; Ellingson, W. A.; Flandermeyer, B. K.; Fousek, R. J.; Heiberger, J. J.

    A unique fuel cell coupled with a low power nuclear reactor presents an attractive approach for SDI burst power requirements. The monolithic fuel cell looks attractive for space applications and represents a quantum jump in fuel cell technology. Such a breakthrough in design is the enabling technology for lightweight, low volume power sources for space based pulse power systems. The monolith is unique among fuel cells in being an all solid state device. The capability for miniaturization, inherent in solid state devices, gives the low volume required for space missions. In addition, the solid oxide fuel cell technology employed in the monolith has high temperature reject heat and can be operated in either closed or open cycles. Both these features are attractive for integration into a burst power system.

  3. Synthesis of transparent nanocomposite monoliths for gamma scintillation

    NASA Astrophysics Data System (ADS)

    Liu, Chao; Hajagos, Tibor J.; Kishpaugh, David; Jin, Yunxia; Hu, Wei; Chen, Qi; Pei, Qibing

    2015-08-01

    During the past decade, inorganic nanoparticles/polymer nanocomposites have been intensively studied to provide a low cost, high performance alternative for gamma scintillation. However, the aggregation of nanoparticles often occurs even at low nanoparticle concentrations and thus deteriorates the transparency and performance of these nanocomposite scintillators. Here we report an efficient fabrication protocol of transparent nanocomposite monoliths based on surface modified hafnium oxide nanoparticles. Using hafnium oxide nanoparticles with surface-grafted methacrylate groups, highly transparent bulk-size nanocomposite monoliths (2 mm thick, transmittance at 550 nm >75%) are fabricated with nanoparticle loadings up to 40 wt% (net hafnium wt% up to 28.5%). These nanocomposite monoliths of 1 cm diameter and 2 mm thickness are capable of producing a full energy photopeak for 662 keV gamma rays, with the best deconvoluted photopeak energy resolution reaching 8%.

  4. Cerec anterior crowns: restorative options with monolithic ceramic materials.

    PubMed

    Reich, Sven; Fiedlar, Kurt

    2013-01-01

    The aim of this article is to discuss the different types of monolithic ceramic crowns that can be placed on anterior teeth with existing shoulder preparations. Anterior crowns were indicated for the teeth 12 to 22 in the present case. The patient, a 65-year-old male, had received all-ceramic crowns 20 years earlier, which had started to develop cracks and palatal fractures over the last few years. The patient's teeth were prepared and four sets of crowns were fabricated using different monolithic ceramic materials: IPS e.max CAD, Cerec Blocs C In, VITABLOCS Real Life, and ENAMIC. Both shade characterization and crystallization firing were performed on the monolithic lithium disilicate glass ceramic crowns. The silicate ceramic crowns received glaze firing alone. The crowns made of hybrid ceramic (ENAMIC) were treated with a polymer sealant. PMID:24555406

  5. Tooth-colored CAD/CAM monolithic restorations.

    PubMed

    Reich, S

    2015-01-01

    A monolithic restoration (also known as a full contour restoration) is one that is manufactured from a single material for the fully anatomic replacement of lost tooth structure. Additional staining (followed by glaze firing if ceramic materials are used) may be performed to enhance the appearance of the restoration. For decades, monolithic restoration has been the standard for inlay and partial crown restorations manufactured by both pressing and computer-aided design and manufacturing (CAD/CAM) techniques. A limited selection of monolithic materials is now available for dental crown and bridge restorations. The IDS (2015) provided an opportunity to learn about and evaluate current trends in this field. In addition to new developments, established materials are also mentioned in this article to complete the picture. In line with the strategic focus of the IJCD, the focus here is naturally on CAD/CAM materials. PMID:26110926

  6. CHARACTERIZATION OF MONOLITHIC FUEL FOIL PROPERTIES AND BOND STRENGTH

    SciTech Connect

    D E Burkes; D D Keiser; D M Wachs; J S Larson; M D Chapple

    2007-03-01

    Understanding fuel foil mechanical properties, and fuel / cladding bond quality and strength in monolithic plates is an important area of investigation and quantification. Specifically, what constitutes an acceptable monolithic fuel – cladding bond, how are the properties of the bond measured and determined, and what is the impact of fabrication process or change in parameters on the level of bonding? Currently, non-bond areas are quantified employing ultrasonic determinations that are challenging to interpret and understand in terms of irradiation impact. Thus, determining mechanical properties of the fuel foil and what constitutes fuel / cladding non-bonds is essential to successful qualification of monolithic fuel plates. Capabilities and tests related to determination of these properties have been implemented at the INL and are discussed, along with preliminary results.

  7. MONOLITHIC FUEL FABRICATION PROCESS DEVELOPMENT AT THE IDAHO NATIONAL LABORATORY_

    SciTech Connect

    G. A. Moore; F. J. Rice; N. E. Woolstenhulme; J-F. Jue; B. H. Park; S. E. Steffler; N. P. Hallinan; M. D. Chapple; M. C. Marshall; B. L. Mackowiak; C. R. Clark; B. H. Rabin

    2009-11-01

    Full-size/prototypic U10Mo monolithic fuel-foils and aluminum clad fuel plates are being developed at the Idaho National Laboratory’s (INL) Materials and Fuels Complex (MFC). These efforts are focused on realizing Low Enriched Uranium (LEU) high density monolithic fuel plates for use in High Performance Research and Test Reactors. The U10Mo fuel foils under development afford a fuel meat density of ~16 gU/cc and thus have the potential to facilitate LEU conversions without any significant reactor-performance penalty. An overview is provided of the ongoing monolithic UMo fuel development effort, including application of a zirconium barrier layer on fuel foils, fabrication scale-up efforts, and development of complex/graded fuel foils. Fuel plate clad bonding processes to be discussed include: Hot Isostatic Pressing (HIP) and Friction Bonding (FB).

  8. Tooth-colored CAD/CAM monolithic restorations.

    PubMed

    Reich, S

    2015-01-01

    A monolithic restoration (also known as a full contour restoration) is one that is manufactured from a single material for the fully anatomic replacement of lost tooth structure. Additional staining (followed by glaze firing if ceramic materials are used) may be performed to enhance the appearance of the restoration. For decades, monolithic restoration has been the standard for inlay and partial crown restorations manufactured by both pressing and computer-aided design and manufacturing (CAD/CAM) techniques. A limited selection of monolithic materials is now available for dental crown and bridge restorations. The IDS (2015) provided an opportunity to learn about and evaluate current trends in this field. In addition to new developments, established materials are also mentioned in this article to complete the picture. In line with the strategic focus of the IJCD, the focus here is naturally on CAD/CAM materials.

  9. A Possible Astronomically Aligned Monolith at Gardom's Edge

    NASA Astrophysics Data System (ADS)

    Brown, Daniel; Alder, Andy; Bemand, Elizabeth

    2015-05-01

    A unique triangular shaped monolith located within the Peak District National Park at Gardom's Edge could be intentionally astronomically aligned. It is set within a landscape rich in late Neolithic and Bronze Age remains. We show that the stone is most likely in its original orientation owing to its clear signs of erosion and associated to the time period of the late Neolithic. It is tilted towards south and its north side slopes at an angle equal to the maximum altitude of the Sun at mid-summer. This alignment emphasizes the changing declinations of the Sun during the seasons as well as giving an indication of mid-summers day. This functionality is achieved by an impressive display of light and shadow on the north facing side of the monolith. Together with other monuments in the close vicinity the monolith would have represented an ideal marker or social arena for seasonal gatherings for the otherwise dispersed small communities.

  10. Record Methane Storage in Monolithic and Powdered Activated Carbons

    NASA Astrophysics Data System (ADS)

    Soo, Yuchoong; Nordwald, E.; Hester, B.; Romanos, J.; Isaacson, B.; Stalla, D.; Moore, D.; Kraus, M.; Burress, J.; Dohnke, E.; Pfeifer, P.

    2010-03-01

    The Alliance for Collaborative Research in Alternative Fuel Technology (ALL-CRAFT) has developed activated carbons from corn cob as adsorbent materials for methane gas storage by physisorption at low pressures. KOH activated carbons were compressed into carbon monolith using chemical binders. High pressure methane isotherms up to 250 bar at room temperature on monolithic and powdered activated carbons were measured gravimetrically and volumetrically. Record methane storage capacities of 250 g CH4/kg carbon and 130 g CH4/liter carbon at 35 bar and 293 K have been achieved. BET surface area, porosity, and pore size distributions were measured from sub-critical nitrogen isotherms. Pore entrances were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A prototype adsorbed natural gas (ANG) tank, loaded with carbon monoliths, was tested in Kansas City.

  11. Preparation of poly(γ-glutamic acid)/hydroxyapatite monolith via biomineralization for bone tissue engineering.

    PubMed

    Park, Sung-Bin; Hasegawa, Urara; van der Vlies, André J; Sung, Moon-Hee; Uyama, Hiroshi

    2014-01-01

    A hybrid monolith of poly(γ-glutamic acid) and hydroxyapatite (PGA/HAp monolith) was prepared via biomineralization and used as a macroporous cell scaffold in bone tissue engineering. The PGA monolith having a bimodal pore size distribution was used as a substrate to induce biomineralization. The PGA/HAp monolith was obtained by immersing the PGA monolith in simulated body fluid. Pretreatment with CaCl2 enhanced the apatite-forming ability of the PGA monolith. Murine osteoblastic MC3T3-E1 cells efficiently attached and proliferated on the PGA/HAp monolith. MTT assay showed that both the PGA and PGA/HAp monolith did not have apparent cytotoxicity. Moreover, the PGA and PGA/HAp monoliths adsorbed bone morphogenetic protein-2 (BMP-2) by electrostatic interaction which was slowly released in the medium during cell culture. The PGA/HAp monolith enhanced BMP-2 induced alkaline phosphatase activity compared to the PGA monolith and a polystyrene culture plate. Thus, these PGA/HAp monoliths may have potential in bone tissue engineering.

  12. A Monolithic Oxide-Based Transversal Thermoelectric Energy Harvester

    NASA Astrophysics Data System (ADS)

    Teichert, S.; Bochmann, A.; Reimann, T.; Schulz, T.; Dreßler, C.; Udich, S.; Töpfer, J.

    2016-03-01

    We report the fabrication and properties of a monolithic transversal thermoelectric energy harvester based on the combination of a thermoelectric oxide and a metal. The fabrication of the device is done with a ceramic multilayer technology using printing and co-firing processes. Five transversal devices were combined to a meander-like thermoelectric generator. Electrical measurements and finite element calculations were performed to characterize the resulting thermoelectric generator. A maximum experimental electrical power output of 30.2 mW at a temperature difference of {Δ }T = 208 K was found. The prepared monolithic thermoelectric generator provides at {Δ }T = 35 K sufficient energy to drive a simple electronic sensor application.

  13. A hybrid fluorous monolithic capillary column with integrated nanoelectrospray ionization emitter for determination of perfluoroalkyl acids by nano-liquid chromatography-nanoelectrospray ionization-mass spectrometry/mass spectrometry.

    PubMed

    Zhang, Haiyang; Ou, Junjie; Wei, Yinmao; Wang, Hongwei; Liu, Zhongshan; Zou, Hanfa

    2016-04-01

    A hybrid fluorous monolithic column was simply prepared via photo-initiated free radical polymerization of an acrylopropyl polyhedral oligomeric silsesquioxane (acryl-POSS) and a perfluorous monomer (2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate) in UV-transparent fused-silica capillaries within 5min. The physical characterization of hybrid fluorous monolith, including scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption measurement was performed. Chromatographic performance was also evaluated by capillary liquid chromatography (cLC). Due to the fluorous-fluorous interaction between fluorous monolith and analytes, fluorobenzenes could well be separated, and the column efficiencies reached 86,600-92,500plates/m at the velocity of 0.87mm/s for alkylbenzenes and 51,900-76,000plates/m at the velocity of 1.10mm/s for fluorobenzenes. Meanwhile, an approach to integrate nanoelectrospray ionization (ESI) emitter with hybrid fluorous monolithic column was developed for quantitative determination of perfluoroalkyl acids by nanoHPLC-ESI-MS/MS. The integration design could minimize extracolumn volume, thus excluding undesirable peak broadening and improving separation performance. PMID:26916593

  14. A hybrid fluorous monolithic capillary column with integrated nanoelectrospray ionization emitter for determination of perfluoroalkyl acids by nano-liquid chromatography-nanoelectrospray ionization-mass spectrometry/mass spectrometry.

    PubMed

    Zhang, Haiyang; Ou, Junjie; Wei, Yinmao; Wang, Hongwei; Liu, Zhongshan; Zou, Hanfa

    2016-04-01

    A hybrid fluorous monolithic column was simply prepared via photo-initiated free radical polymerization of an acrylopropyl polyhedral oligomeric silsesquioxane (acryl-POSS) and a perfluorous monomer (2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate) in UV-transparent fused-silica capillaries within 5min. The physical characterization of hybrid fluorous monolith, including scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption measurement was performed. Chromatographic performance was also evaluated by capillary liquid chromatography (cLC). Due to the fluorous-fluorous interaction between fluorous monolith and analytes, fluorobenzenes could well be separated, and the column efficiencies reached 86,600-92,500plates/m at the velocity of 0.87mm/s for alkylbenzenes and 51,900-76,000plates/m at the velocity of 1.10mm/s for fluorobenzenes. Meanwhile, an approach to integrate nanoelectrospray ionization (ESI) emitter with hybrid fluorous monolithic column was developed for quantitative determination of perfluoroalkyl acids by nanoHPLC-ESI-MS/MS. The integration design could minimize extracolumn volume, thus excluding undesirable peak broadening and improving separation performance.

  15. On the use of mesophase pitch for the preparation of hierarchical porous carbon monoliths by nanocasting

    NASA Astrophysics Data System (ADS)

    Adelhelm, Philipp; Cabrera, Karin; Smarsly, Bernd M.

    2012-02-01

    A detailed study is given on the synthesis of a hierarchical porous carbon, possessing both meso- and macropores, using a mesophase pitch (MP) as the carbon precursor. This carbon material is prepared by the nanocasting approach involving the replication of a porous silica monolith (hard templating). While this carbon material has already been tested in energy storage applications, various detailed aspects of its formation and structure are addressed in this study. Scanning electron microscopy (SEM), Hg porosimetry and N2 physisorption are used to characterize the morphology and porosity of the carbon replica. A novel approach for the detailed analysis of wide-angle x-ray scattering (WAXS) from non-graphitic carbons is applied to quantitatively compare the graphene microstructures of carbons prepared using MP and furfuryl alcohol (FA). This WAXS analysis underlines the importance of the carbon precursor in the synthesis of templated porous carbon materials via the nanocasting route. Our study demonstrates that a mesophase pitch is a superior precursor whenever a high-purity, low-micropore-content and well-developed graphene structure is desired.

  16. A monolithic array of three-dimensional ion traps fabricated with conventional semiconductor technology.

    PubMed

    Wilpers, Guido; See, Patrick; Gill, Patrick; Sinclair, Alastair G

    2012-09-01

    The coherent control of quantum-entangled states of trapped ions has led to significant advances in quantum information, quantum simulation, quantum metrology and laboratory tests of quantum mechanics and relativity. All of the basic requirements for processing quantum information with arrays of ion-based quantum bits (qubits) have been proven in principle. However, so far, no more than 14 ion-based qubits have been entangled with the ion-trap approach, so there is a clear need for arrays of ion traps that can handle a much larger number of qubits. Traps consisting of a two-dimensional electrode array have undergone significant development, but three-dimensional trap geometries can create a superior confining potential. However, existing three-dimensional approaches, as used in the most advanced experiments with trap arrays, cannot be scaled up to handle greatly increased numbers of ions. Here, we report a monolithic three-dimensional ion microtrap array etched from a silica-on-silicon wafer using conventional semiconductor fabrication technology. We have confined individual (88)Sr(+) ions and strings of up to 14 ions in a single segment of the array. We have measured motional frequencies, ion heating rates and storage times. Our results demonstrate that it should be possible to handle several tens of ion-based qubits with this approach. PMID:22820742

  17. Integrated strong cation-exchange hybrid monolith coupled with capillary zone electrophoresis and simultaneous dynamic pH junction for large-volume proteomic analysis by mass spectrometry.

    PubMed

    Zhang, Zhenbin; Sun, Liangliang; Zhu, Guijie; Yan, Xiaojing; Dovichi, Norman J

    2015-06-01

    A sulfonate-silica hybrid strong cation-exchange (SCX) monolith was synthesized at the proximal end of a capillary zone electrophoresis column and used for on-line solid-phase extraction (SPE) sample preconcentration. Sample was prepared in an acidic buffer and deposited onto the SCX-SPE monolith and eluted using a basic buffer. Electrophoresis was performed in an acidic buffer. This combination of buffers results in formation of a dynamic pH junction, which allows use of relatively large elution buffer volume while maintaining peak efficiency and resolution. All experiments were performed with a 50 µm ID capillary, a 1cm long SCX-SPE monolith, a 60cm long separation capillary, and a electrokinetically pumped nanospray interface. The volume of the capillary is 1.1 µL. By loading 21 µL of a 1×10(-7) M angiotensin II solution, an enrichment factor of 3000 compared to standard electrokinetic injection was achieved on this platform while retaining efficient electrophoretic performance (N=44,000 plates). The loading capacity of the sulfonate SCX hybrid monolith was determined to be ~15 pmol by frontal analysis with 10(-5) M angiotensin II. The system was also applied to the analysis of a 10(-4) mg/mL bovine serum albumin tryptic digest; the protein coverage was 12% and 11 peptides were identified. Finally, by loading 5.5 µL of a 10(-3) mg/mL E. coli digest, 109 proteins and 271 peptides were identified in a 20 min separation; the median separation efficiency generated by these peptides was 25,000 theoretical plates.

  18. A novel polymeric monolith prepared with multi-acrylate crosslinker for retention-independent efficient separation of small molecules in capillary liquid chromatography.

    PubMed

    Zhang, Haiyang; Ou, Junjie; Wei, Yinmao; Wang, Hongwei; Liu, Zhongshan; Chen, Lianfang; Zou, Hanfa

    2015-07-01

    Low column efficiency for small molecules in reversed-phase chromatography is a major problem commonly encountered in polymer-based monoliths. Herein, a novel highly crosslinked porous polymeric monolith was in situ prepared by using a multi-acrylate monomer, dipentaerythritol penta-/hexa-acrylate (DPEPA), as crosslinker, which copolymerized with lauryl methacrylate (LMA) as functional monomer in a UV-transparent fused-silica capillary via photo-initiated free-radical polymerization within 5 min. The mechanical stability and permeability of the resulting poly(LMA-co-DPEPA) monolith were characterized in detail. One series of highly crosslinked poly(LMA-co-DPEPA) columns were prepared with relatively higher content of crosslinker (63.3%) in the precursor. Although they exhibited lower permeability, high column efficiency for alkylbenzenes was acquired in cLC, and the minimum plate height (column B) was in the range of 6.04-9.00 μm, corresponding to 111,000-165,000 N m(-1). Meanwhile, another series of poly(LMA-co-DPEPA) columns prepared with relatively lower content of crosslinker (52.7%) in the precursor exhibited higher permeability, but the minimum plate height (column E) was relatively low in the range of 10.75-20.04 μm for alkylbenzenes, corresponding to 50,000-93,000 N m(-1). Compared with common poly(LMA-co-EDMA) columns previously reported, the highly crosslinked poly(LMA-co-DPEPA) columns using a multi-acrylate monomer as crosslinker possessed remarkably high column efficiency for small molecules in cLC. By plotting of plate height (H) of alkylbenzenes versus the linear velocity (u) of mobile phase, the results revealed a retention-independent efficient performance of small molecules in the isocratic elution, indicating that the use of multi-functional crosslinker possibly prevents the generation of gel-like micropores in the poly(LMA-co-DPEPA) monolith, reducing the mass transfer resistance (C-term).

  19. Monolithic Flexure Pre-Stressed Ultrasonic Horns

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph; Allen, Phillip Grant

    2011-01-01

    High-power ultrasonic actuators are generally assembled with a horn, backing, stress bolt, piezoelectric rings, and electrodes. The manufacturing process is complex, expensive, difficult, and time-consuming. The internal stress bolt needs to be insulated and presents a potential internal discharge point, which can decrease actuator life. Also, the introduction of a center hole for the bolt causes many failures, reducing the throughput of the manufactured actuators. A new design has been developed for producing ultrasonic horn actuators. This design consists of using flexures rather than stress bolts, allowing one to apply pre-load to the piezoelectric material. It also allows one to manufacture them from a single material/plate, rapid prototype them, or make an array in a plate or 3D structure. The actuator is easily assembled, and application of pre-stress greater than 25 MPa was demonstrated. The horn consists of external flexures that eliminate the need for the conventional stress bolt internal to the piezoelectric, and reduces the related complexity. The stress bolts are required in existing horns to provide prestress on piezoelectric stacks when driven at high power levels. In addition, the manufacturing process benefits from the amenability to produce horn structures with internal cavities. The removal of the pre-stress bolt removes a potential internal electric discharge point in the actuator. In addition, it significantly reduces the chances of mechanical failure in the piezoelectric stacks that result from the hole surface in conventional piezoelectric actuators. The novel features of this disclosure are: 1. A design that can be manufactured from a single piece of metal using EDM, precision machining, or rapid prototyping. 2. Increased electromechanical coupling of the horn actuator. 3. Higher energy density. 4. A monolithic structure of a horn that consists of an external flexure or flexures that can be used to pre-stress a solid piezoelectric structure

  20. Constitutive Theory Developed for Monolithic Ceramic Materials

    NASA Technical Reports Server (NTRS)

    Janosik, Lesley A.

    1998-01-01

    with these service conditions by developing a multiaxial viscoplastic constitutive model that accounts for time-dependent hereditary material deformation (such as creep and stress relaxation) in monolithic structural ceramics. Using continuum principles of engineering mechanics, we derived the complete viscoplastic theory from a scalar dissipative potential function.

  1. Development and characterization of methacrylate-based hydrazide monoliths for oriented immobilization of antibodies.

    PubMed

    Brne, P; Lim, Y-P; Podgornik, A; Barut, M; Pihlar, B; Strancar, A

    2009-03-27

    Convective interaction media (CIM; BIA Separations) monoliths are attractive stationary phases for use in affinity chromatography because they enable fast affinity binding, which is a consequence of convectively enhanced mass transport. This work focuses on the development of novel CIM hydrazide (HZ) monoliths for the oriented immobilization of antibodies. Adipic acid dihydrazide (AADH) was covalently bound to CIM epoxy monoliths to gain hydrazide groups on the monolith surface. Two different antibodies were afterwards immobilized to hydrazide functionalized monolithic columns and prepared columns were tested for their selectivity. One column was further tested for the dynamic binding capacity. PMID:19203754

  2. Reduction of absorption loss in silica-on-silicon channel waveguides fabricated by low-temperature PECVD process

    NASA Astrophysics Data System (ADS)

    Sahu, Jayanta K.; Wosinski, Lech; Fernando, Harendra

    1999-12-01

    This study is focused on the low temperature plasma enhanced chemical vapor deposition technique used for fabrication of silica based optical waveguides on silicon, utilizing nitrous oxide as an oxidant for both silane and dopant. Fabricated channel waveguide shows total insertion loss of 1.2 dB at 1.55 micrometers , and no absorption peaks associated with N-H and Si-H bonds around 1.5 micrometers have been observed in the as deposited material. This fabrication technology adds flexibility to the monolithic integration of electronic and optical components. Using this technology, a n umber of different couplers based on multimode interference technique have been investigated.

  3. Preparation of phenylboronate affinity rigid monolith with macromolecular porogen.

    PubMed

    Li, Xiang-Jie; Jia, Man; Zhao, Yong-Xin; Liu, Zhao-Sheng; Akber Aisa, Haji

    2016-03-18

    Boronate-affinity monolithic column was first prepared via polystyrene (PS) as porogen in this work. The monolithic polymer was synthetized using 4-vinylphenylboronic acid (4-VPBA) as functional monomer, ethylene glycol dimethacrylate (EDMA) as crosslinker monomer, and a mixture of PS solution in tetrahydrofuran, the linear macromolecular porogen, and toluene as porogen. Isoquercitrin (ISO) and hyperoside (HYP), isomer diol flavonoid glycosides, can be baseline separated on the poly(VPBA-co-EDMA) monolith. The effect of polymerization variables on the selectivity factor, e.g., the ratio of monomer to crosslinker (M/C), the amount of PS and the molecular weight of macromolecular porogen was investigated. The surface properties of the monolithic polymer were characterized by scanning electron microscopy and nitrogen adsorption. The best polymerization condition was the M/C ratio of 7:3, and the PS concentration of 40 mg/ml. The poly(VPBA-co-EDMA) polymer was also applied to extract cis-diol flavonoid glycosides from the crude extraction of cotton flower. After treated by poly(VPBA-co-EDMA) for solid phase extraction, high purity ISO and HYP (>99.96%) can be obtained with recovery of 83.7% and 78.6%, respectively. PMID:26896914

  4. Mechanical monolithic sensor for low frequency seismic noise measurement

    NASA Astrophysics Data System (ADS)

    Acernese, Fausto; De Rosa, Rosario; Giordano, Gerardo; Romano, Rocco; Barone, Fabrizio

    2007-10-01

    This paper describes a mechanical monolithic sensor for geophysical applications developed at the University of Salerno. The instrument is basically a monolithic tunable folded pendulum, shaped with precision machining and electric-discharge-machining, that can be used both as seismometer and, in a force-feedback configuration, as accelerometer. The monolithic mechanical design and the introduction of laser interferometric techniques for the readout implementation make it a very compact instrument, very sensitive in the low-frequency seismic noise band, with a very good immunity to environmental noises. Many changes have been produced since last version (2006), mainly aimed to the improvement of the mechanics and of the optical readout of the instrument. In fact, we have developed and tested a prototype with elliptical hinges and mechanical tuning of the resonance frequency together with a new laser optical lever and laser interferometer readout system. The theoretical sensitivity curve for both laser optical lever and laser interferometric readouts, calculated on the basis of suitable theoretical models, shows a very good agreement with the experimental measurements. Very interesting scientific result is that the measured natural resonance frequency of the instrument is ~ 70mHz with a Q ~ 140 in air without thermal stabilization, demonstrating the feasibility of a monolithic FP sensor with a natural resonance frequency of the order of 5 mHz with a more refined mechanical tuning.

  5. Mechanical monolithic horizontal sensor for low frequency seismic noise measurement

    NASA Astrophysics Data System (ADS)

    Acernese, Fausto; Giordano, Gerardo; Romano, Rocco; De Rosa, Rosario; Barone, Fabrizio

    2008-07-01

    This paper describes a mechanical monolithic horizontal sensor for geophysical applications developed at the University of Salerno. The instrument is basically a monolithic tunable folded pendulum, shaped with precision machining and electric discharge machining, that can be used both as seismometer and, in a force-feedback configuration, as accelerometer. The monolithic mechanical design and the introduction of laser interferometric techniques for the readout implementation makes it a very compact instrument, very sensitive in the low frequency seismic noise band, with a very good immunity to environmental noises. Many changes have been produced since last version (2007), mainly aimed to the improvement of the mechanics and of the optical readout of the instrument. In fact, we have developed and tested a prototype with elliptical hinges and mechanical tuning of the resonance frequency together with a laser optical lever and a new laser interferometer readout system. The theoretical sensitivity curve for both laser optical lever and laser interferometric readouts, evaluated on the basis of suitable theoretical models, shows a very good agreement with the experimental measurements. Very interesting scientific result is the measured natural resonance frequency of the instrument of 70mHz with a Q =140 in air without thermal stabilization. This result demonstrates the feasibility of a monolithic folded pendulum sensor with a natural resonance frequency of the order of millihertz with a more refined mechanical tuning.

  6. Cyclodextrin-Functionalized Monolithic Capillary Columns: Preparation and Chiral Applications.

    PubMed

    Adly, Frady G; Antwi, Nana Yaa; Ghanem, Ashraf

    2016-02-01

    In this review, the recently reported approaches for the preparation of cyclodextrin-functionalized capillary monolithic columns are highlighted, with few applications in chiral separations using capillary liquid chromatography (CLC) and capillary electrochromatography (CEC). Chirality 28:97-109, 2016. © 2015 Wiley Periodicals, Inc.

  7. From 1D to 3D - macroscopic nanowire aerogel monoliths.

    PubMed

    Cheng, Wei; Rechberger, Felix; Niederberger, Markus

    2016-08-01

    Here we present a strategy to assemble one-dimensional nanostructures into a three-dimensional architecture with macroscopic size. With the assistance of centrifugation, we successfully gel ultrathin W18O49 nanowires with diameters of 1 to 2 nm and aspect ratios larger than 100 into 3D networks, which are transformed into monolithic aerogels by supercritical drying. PMID:27389477

  8. Fischer-Tropsch Synthesis on Ceramic Monolith-Structured Catalysts

    SciTech Connect

    Wang, Yong; Liu, Wei

    2009-04-19

    This paper reports recent research results about impact of different catalyst bed configurations on FT reaction product distribution. A CoRe/γ-alumina catalyst is prepared in bulk particle form and tested in the packed bed reactor at a size of 60 to 100 mesh. The same catalyst is ball milled and coated on a ceramic monolith support structure of channel size about 1mm. The monolith catalyst module is tested in two different ways, as a whole piece and as well-defined channels. Steady-state reaction conversion is measured at various temperatures under constant H2/CO feed ratio of 2 and reactor pressure of 25 bar. Detailed product analysis is performed. Significant formation of wax is evident with the packed particle bed and with the monolith catalyst that is improperly packed. By contrast, the wax formation is not detected in the liquid product by confining the reactions inside the monolith channel. This study presents an important finding about the structured catalyst/reactor system that the product distribution highly depends on the way how the structured reactor is set up. Even if the same catalyst and same reaction conditions (T, P, H2/oil ratio) are used, hydrodynamics (or flow conditions) inside a structured channel can have a significant impact on the product distribution.

  9. Preparation of phenylboronate affinity rigid monolith with macromolecular porogen.

    PubMed

    Li, Xiang-Jie; Jia, Man; Zhao, Yong-Xin; Liu, Zhao-Sheng; Akber Aisa, Haji

    2016-03-18

    Boronate-affinity monolithic column was first prepared via polystyrene (PS) as porogen in this work. The monolithic polymer was synthetized using 4-vinylphenylboronic acid (4-VPBA) as functional monomer, ethylene glycol dimethacrylate (EDMA) as crosslinker monomer, and a mixture of PS solution in tetrahydrofuran, the linear macromolecular porogen, and toluene as porogen. Isoquercitrin (ISO) and hyperoside (HYP), isomer diol flavonoid glycosides, can be baseline separated on the poly(VPBA-co-EDMA) monolith. The effect of polymerization variables on the selectivity factor, e.g., the ratio of monomer to crosslinker (M/C), the amount of PS and the molecular weight of macromolecular porogen was investigated. The surface properties of the monolithic polymer were characterized by scanning electron microscopy and nitrogen adsorption. The best polymerization condition was the M/C ratio of 7:3, and the PS concentration of 40 mg/ml. The poly(VPBA-co-EDMA) polymer was also applied to extract cis-diol flavonoid glycosides from the crude extraction of cotton flower. After treated by poly(VPBA-co-EDMA) for solid phase extraction, high purity ISO and HYP (>99.96%) can be obtained with recovery of 83.7% and 78.6%, respectively.

  10. Three-dimensional developing flow model for photocatalytic monolith reactors

    SciTech Connect

    Hossain, Md.M.; Raupp, G.B.; Hay, S.O.; Obee, T.N.

    1999-06-01

    A first-principles mathematical model describes performance of a titania-coated honeycomb monolith photocatalytic oxidation (PCO) reactor for air purification. The single-channel, 3-D convection-diffusion-reaction model assumes steady-state operation, negligible axial dispersion, and negligible homogeneous reaction. The reactor model accounts rigorously for entrance effects arising from the developing fluid-flow field and uses a previously developed first-principles radiation-field submodel for the UV flux profile down the monolith length. The model requires specification of an intrinsic photocatalytic reaction rate dependent on local UV light intensity and local reactant concentration, and uses reaction-rate expressions and kinetic parameters determined independently using a flat-plate reactor. Model predictions matched experimental pilot-scale formaldehyde conversion measurements for a range of inlet formaldehyde concentrations, air humidity levels, monolith lengths, and for various monolith/lamp-bank configurations. This agreement was realized without benefit of any adjustable photocatalytic reactor model parameters, radiation-field submodel parameters, or kinetic submodel parameters. The model tends to systematically overpredict toluene conversion data by about 33%, which falls within the accepted limits of experimental kinetic parameter accuracy. With further validation, the model could be used in PCO reactor design and to develop quantitative energy utilization metrics.

  11. Translucency of monolithic and core zirconia after hydrothermal aging

    PubMed Central

    Fathy, Salma M.; El-Fallal, Abeer A.; El-Negoly, Salwa A.; El Bedawy, Abu Baker

    2015-01-01

    Abstract Objective: To evaluate the hydrothermal aging effect on the translucency of partially stabilized tetragonal zirconia with yttria (Y-TZP) used as monolithic or fully milled zirconia and of core type. Methods: Twenty disc-shaped specimens (1 and 10 mm) for each type of monolithic and core Y-TZP materials were milled and sintered according to the manufacturer’s instruction. The final specimens were divided into two groups according to the type of Y-TZP used. Translucency parameter (TP) was measured over white and black backgrounds with the diffuse reflectance method; X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to analyze the microstructure of both Y-TZP types before and after aging. Data for TP values was statistically analyzed using Student’s t-test. Results: Monolithic Y-TZP showed the highest TP mean value (16.4 ± 0.316) before aging while core Y-TZP showed the lowest TP mean value (7.05 ± 0.261) after aging. There was a significant difference between the two Y-TZP types before and after hydrothermal aging. XRD analysis showed increases in monoclinic content in both Y-TZP surfaces after aging. Conclusion: Monolithic Y-TZP has a higher chance to low-temperature degradation than core type, which may significantly affect the esthetic appearance and translucency hence durability of translucent Y-TZP. PMID:27335897

  12. Single-frequency lasing of monolithic Ho,Tm:YLF

    NASA Technical Reports Server (NTRS)

    Koch, Grady J.; Deyst, John P.; Storm, Mark E.

    1993-01-01

    Single-frequency lasing in monolithic crystals of holmium-thulium-doped YLF (Ho,Tm:YLF) is reported. A maximum single-frequency output power of 6 mW at a wavelength of 2.05 microns is demonstrated. Frequency tuning is also described.

  13. Dual-band microstrip antennas with monolithic reactive loading

    NASA Technical Reports Server (NTRS)

    Davidson, S. E.; Long, S. A.; Richards, W. F.

    1985-01-01

    The design and experimental measurement of a dual-band, monolithic microstrip antenna is presented. The structure utilises a short-circuited length of microstrip transmission line to provide reactive loading and, thereby, retains the low-profile characteristic of a normal microstrip patch radiator.

  14. Monolithic fuel cell based power source for burst power generation

    SciTech Connect

    Fee, D.C.; Blackburn, P.E.; Busch, D.E.; Dees, D.W.; Dusek, J.; Easler, T.E.; Ellingson, W.A.; Flandermeyer, B.K.; Fousek, R.J.; Heiberger, J.J.; Majumdar, S.; McPheeters, C.C.; Mrazek, F.C.; Picciolo, J.J.; Singh, J.P.; Poeppel, R.B.

    1988-01-01

    A unique fuel cell coupled with a low power nuclear reactor presents an attractive approach for SDI burst power requirements. The requisite high power, long-duration bursts appear achievable with appropriate development of the concept. A monolithic fuel cell/nuclear reactor system clearly possesses several advantages. Fabrication methods, performance advantages, and applications are discussed in this report.

  15. Monolithic natural gas storage delivery system based on sorbents

    DOEpatents

    Hornbostel, Marc; Krishnan, Gopala N.; Sanjurjo, Angel

    2016-09-27

    The invention provides methods for producing a strong, light, sorbent-based storage/dispenser system for gases and fuels. The system comprises a porous monolithic material with an adherent strong impervious skin that is capable of storing a gas under pressure in a safe and usable manner.

  16. MONOLITHIC FUEL FABRICATION PROCESS DEVELOPMENT AT THE IDAHO NATIONAL LABORATORY

    SciTech Connect

    Glenn A. Moore; Francine J. Rice; Nicolas E. Woolstenhulme; W. David SwanK; DeLon C. Haggard; Jan-Fong Jue; Blair H. Park; Steven E. Steffler; N. Pat Hallinan; Michael D. Chapple; Douglas E. Burkes

    2008-10-01

    Within the Reduced Enrichment for Research and Test Reactors (RERTR) program directed by the US Department of Energy (DOE), UMo fuel-foils are being developed in an effort to realize high density monolithic fuel plates for use in high-flux research and test reactors. Namely, targeted are reactors that are not amenable to Low Enriched Uranium (LEU) fuel conversion via utilization of high density dispersion-based fuels, i.e. 8-9 gU/cc. LEU conversion of reactors having a need for >8-9 gU/cc fuel density will only be possible by way of monolithic fuel forms. The UMo fuel foils under development afford fuel meat density of ~16 gU/cc and thus have the potential to facilitate LEU conversions without any significant reactor-performance penalty. Two primary challenges have been established with respect to UMo monolithic fuel development; namely, fuel element fabrication and in-reactor fuel element performance. Both issues are being addressed concurrently at the Idaho National Laboratory. An overview is provided of the ongoing monolithic UMo fuel development effort at the Idaho National Laboratory (INL); including development of complex/graded fuel foils. Fabrication processes to be discussed include: UMo alloying and casting, foil fabrication via hot rolling, fuel-clad interlayer application via co-rolling and thermal spray processes, clad bonding via Hot Isostatic Pressing (HIP) and Friction Bonding (FB), and fuel plate finishing.

  17. A monolithically-integrated μGC chemical sensor system.

    PubMed

    Manginell, Ronald P; Bauer, Joseph M; Moorman, Matthew W; Sanchez, Lawrence J; Anderson, John M; Whiting, Joshua J; Porter, Daniel A; Copic, Davor; Achyuthan, Komandoor E

    2011-01-01

    Gas chromatography (GC) is used for organic and inorganic gas detection with a range of applications including screening for chemical warfare agents (CWA), breath analysis for diagnostics or law enforcement purposes, and air pollutants/indoor air quality monitoring of homes and commercial buildings. A field-portable, light weight, low power, rapid response, micro-gas chromatography (μGC) system is essential for such applications. We describe the design, fabrication and packaging of μGC on monolithically-integrated Si dies, comprised of a preconcentrator (PC), μGC column, detector and coatings for each of these components. An important feature of our system is that the same mechanical micro resonator design is used for the PC and detector. We demonstrate system performance by detecting four different CWA simulants within 2 min. We present theoretical analyses for cost/power comparisons of monolithic versus hybrid μGC systems. We discuss thermal isolation in monolithic systems to improve overall performance. Our monolithically-integrated μGC, relative to its hybrid cousin, will afford equal or slightly lower cost, a footprint that is 1/2 to 1/3 the size and an improved resolution of 4 to 25%. PMID:22163970

  18. From 1D to 3D - macroscopic nanowire aerogel monoliths.

    PubMed

    Cheng, Wei; Rechberger, Felix; Niederberger, Markus

    2016-08-01

    Here we present a strategy to assemble one-dimensional nanostructures into a three-dimensional architecture with macroscopic size. With the assistance of centrifugation, we successfully gel ultrathin W18O49 nanowires with diameters of 1 to 2 nm and aspect ratios larger than 100 into 3D networks, which are transformed into monolithic aerogels by supercritical drying.

  19. Shear bond strength of indirect composite material to monolithic zirconia

    PubMed Central

    2016-01-01

    PURPOSE This study aimed to evaluate the effect of surface treatments on bond strength of indirect composite material (Tescera Indirect Composite System) to monolithic zirconia (inCoris TZI). MATERIALS AND METHODS Partially stabilized monolithic zirconia blocks were cut into with 2.0 mm thickness. Sintered zirconia specimens were divided into different surface treatment groups: no treatment (control), sandblasting, glaze layer & hydrofluoric acid application, and sandblasting + glaze layer & hydrofluoric acid application. The indirect composite material was applied to the surface of the monolithic zirconia specimens. Shear bond strength value of each specimen was evaluated after thermocycling. The fractured surface of each specimen was examined with a stereomicroscope and a scanning electron microscope to assess the failure types. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey LSD tests (α=.05). RESULTS Bond strength was significantly lower in untreated specimens than in sandblasted specimens (P<.05). No difference between the glaze layer and hydrofluoric acid application treated groups were observed. However, bond strength for these groups were significantly higher as compared with the other two groups (P<.05). CONCLUSION Combined use of glaze layer & hydrofluoric acid application and silanization are reliable for strong and durable bonding between indirect composite material and monolithic zirconia. PMID:27555895

  20. Macroscopic Carbon Nanotube-based 3D Monoliths.

    PubMed

    Du, Ran; Zhao, Qiuchen; Zhang, Na; Zhang, Jin

    2015-07-15

    Carbon nanotubes (CNTs) are one of the most promising carbon allotropes with incredible diverse physicochemical properties, thereby enjoying continuous worldwide attention since their discovery about two decades ago. From the point of view of practical applications, assembling individual CNTs into macroscopic functional and high-performance materials is of paramount importance. For example, multiscaled CNT-based assemblies including 1D fibers, 2D films, and 3D monoliths have been developed. Among all of these, monolithic 3D CNT architectures with porous structures have attracted increasing interest in the last few years. In this form, theoretically all individual CNTs are well connected and fully expose their surfaces. These 3D architectures have huge specific surface areas, hierarchical pores, and interconnected conductive networks, resulting in enhanced mass/electron transport and countless accessible active sites for diverse applications (e.g. catalysis, capacitors, and sorption). More importantly, the monolithic form of 3D CNT assemblies can impart additional application potentials to materials, such as free-standing electrodes, sensors, and recyclable sorbents. However, scaling the properties of individual CNTs to 3D assemblies, improving use of the diverse, structure-dependent properties of CNTs, and increasing the performance-to-cost ratio are great unsolved challenges for their real commercialization. This review aims to provide a comprehensive introduction of this young and energetic field, i.e., CNT-based 3D monoliths, with a focus on the preparation principles, current synthetic methods, and typical applications. Opportunities and challenges in this field are also presented.

  1. 26. SPILLWAY CHANNEL WALLS REINF. DETAILS; MONOLITHS W1 TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. SPILLWAY CHANNEL WALLS - REINF. DETAILS; MONOLITHS W-1 TO W-4 INCL. Sheet S-26, July, 1939. File no. SA 342/34. - Prado Dam, Spillway, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  2. 24. SPILLWAY CHANNEL WALLS REINFORCEMENT DETAILS; MONOLITHS E1 TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. SPILLWAY CHANNEL WALLS - REINFORCEMENT DETAILS; MONOLITHS E-1 TO F-4 INCL. & NO. 34. Sheet S-11, June, 1939. File no. SA 342/24(?). - Prado Dam, Spillway, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  3. Polymer-Silica Nanocomposites: A Versatile Platform for Multifunctional Materials

    NASA Astrophysics Data System (ADS)

    Chiu, Chi-Kai

    Solution sol-gel synthesis is a versatile approach to create polymer-silica nanocomposite materials. The solution-to-solid transformation results in a solid consisting of interconnected nanoporous structure in 3D space, making it the ideal material for filtration, encapsulation, optics, electronics, drug release, and biomaterials, etc. Although the pore between nano and meso size may be tunable using different reaction conditions, the intrinsic properties such as limited diffusion within pore structure, complicated interfacial interactions at the pore surfaces, shrinkage and stress-induced cracking and brittleness have limited the applications of this material. To overcome these problems, diffusion, pore size, shrinkage and stress-induced defects need further investigation. Thus, the presented thesis will address these important questions such as whether these limitations can be utilized as the novel method to create new materials and lead to new applications. First, the behaviors of polymers such as poly(ethylene glycol) inside the silica pores are examined by studying the nucleation and growth of AgCl at the surface of the porous matrix. The pore structure and the pressure induced by the shrinkage affect have been found to induce the growth of AgCl nanocrystals. When the same process is carried out at 160 °C, silver metallization is possible. Due to the shrinkage-induced stresses, the polymer tends to move into open crack spaces and exterior surfaces, forming interconnected silver structure. This interconnected silver structure is very unique because its density is not related to the size scale of nanopore structures. These findings suggest that it is possible to utilize defect surface of silica material as the template to create interconnected silver structure. When the scale is small, polymer may no longer be needed if the diffusion length of Ag is more than the size of silica particles. To validate our assumption, monoliths of sol-gel sample containing AgNO3

  4. Ex Situ Integration of Multifunctional Porous Polymer Monoliths into Thermoplastic Microfluidic Chips

    PubMed Central

    Kendall, Eric L.; Wienhold, Erik; Rahmanian, Omid D.; DeVoe, Don L.

    2014-01-01

    A unique method for incorporating functional porous polymer monolith elements into thermoplastic microfluidic chips is described. Monolith elements are formed in a microfabricated mold, rather than within the microchannels, and chemically functionalized off chip before insertion into solvent-softened thermoplastic microchannels during chip assembly. Because monoliths may be trimmed prior to final placement, control of their size, shape, and uniformity is greatly improved over in-situ photopolymerization methods. A characteristic trapezoidal profile facilitates rapid insertion and enables complete mechanical anchoring of the monolith periphery, eliminating the need for chemical attachment to the microchannel walls. Off-chip processing allows the parallel preparation of monoliths of differing compositions and surface chemistries in large batches. Multifunctional flow-through arrays of multiple monolith elements are demonstrated using this approach through the creation of a fluorescent immunosensor with integrated controls, and a microfluidic bubble separator comprising a combination of integrated hydrophobic and hydrophilic monolith elements. PMID:25018587

  5. Facile fabrication of mesoporous poly(ethylene-co-vinyl alcohol)/chitosan blend monoliths.

    PubMed

    Wang, Guowei; Xin, Yuanrong; Uyama, Hiroshi

    2015-11-01

    Poly(ethylene-co-vinyl alcohol) (EVOH)/chitosan blend monoliths were fabricated by thermally-induced phase separation method. Chitosan was successfully incorporated into the polymeric monolith by selecting EVOH as the main component of the monolith. SEM images exhibit that the chitosan was located on the inner surface of the monolith. Fourier-transform infrared analysis and elemental analysis indicate the successful blend of EVOH and chitosan. BET results show that the blend monoliths had high specific surface area and uniform mesopore structure. Good adsorption ability toward various heavy metal ions was found in the blend monoliths due to the large chelation capacity of chitosan. The blend monoliths have potential application for waste water purification or bio-related applications.

  6. Porous graphene oxide/carboxymethyl cellulose monoliths, with high metal ion adsorption.

    PubMed

    Zhang, Yongli; Liu, Yue; Wang, Xinrui; Sun, Zhiming; Ma, Junkui; Wu, Tao; Xing, Fubao; Gao, Jianping

    2014-01-30

    Orderly porous graphene oxide/carboxymethyl cellulose (GO/CMC) monoliths were prepared by a unidirectional freeze-drying method. The porous monoliths were characterized by Fourier transform infrared spectra, X-ray diffraction and scanning electron microscopy. Their properties including compressive strength and moisture adsorption were measured. The incorporation of GO changed the porous structure of the GO/CMC monoliths and significantly increased their compressive strength. The porous GO/CMC monoliths exhibited a strong ability to adsorb metal ions, and the Ni(2+) ions adsorbed on GO/CMC monolith were reduced by NaBH4 to obtain Ni GO/CMC monolith which could be used as catalyst in the reduction of 4-nitrophenol to 4-aminophenol. Since CMC is biodegradable and non-toxic, the porous GO/CMC monoliths are potential environmental adsorbents. PMID:24299788

  7. Precipitated silica as flow regulator.

    PubMed

    Müller, Anne-Kathrin; Ruppel, Joanna; Drexel, Claus-Peter; Zimmermann, Ingfried

    2008-08-01

    Flow regulators are added to solid pharmaceutical formulations to improve the flow properties of the powder mixtures. The primary particles of the flow regulators exist in the form of huge agglomerates which are broken down into smaller aggregates during the blending process. These smaller aggregates adsorb at the surface of the solid's grains and thus diminish attractive Van-der-Waals-forces by increasing the roughness of the host's surface. In most cases amorphous silica is used as flow additive but material properties like particle size or bond strength influence the desagglomeration tendency of the agglomerates and thus the flow regulating potency of each silica. For some silica types we will show that the differences in their flow regulating potency are due to the rate and extent by which they are able to cover the surface of the host particles. Binary powder mixtures consisting of a pharmaceutical excipient and an added flow regulator were blended in a Turbula mixer for a defined period of time. As pharmaceutical excipient corn starch was used. The flow regulators were represented by a selection of amorphous silicon dioxide types like a commercial fumed silica and various types of SIPERNAT precipitated silica provided by Evonik-Degussa GmbH, Hanau, Germany. Flowability parameters of the mixtures were characterized by means of a tensile strength tester. The reduction of tensile strength with the blending time can be correlated with an increase in fragmentation of the flow regulator. PMID:18595668

  8. The Toxicity of Precipitated Silica

    PubMed Central

    Byers, P. D.; Gage, J. C.

    1961-01-01

    The proportion of respirable particles in dust clouds generated from three samples of precipitated silica has been shown to range between one-quarter and one-third by weight. After a single intratracheal dose of the silicas to rats, chemical analysis shows a progressive disappearance of silica from the lungs, though it is still detectable after 12 months. Some silica appears in the liver and kidneys but in two of the three samples none remains after 12 months. The nature and duration of the lung lesions produced in rats after a single intratracheal injection are described. A mild degree of fibrosis was observed which showed a steady regression with time and was to some extent influenced by the nature of the silica injected. The lesions showed little resemblance to those arising from quartz and were more akin to those produced by non-fibrogenic dusts. Recommendations are made for the precautions to be taken during the industrial handling of these dusts. Images PMID:13875292

  9. Evaluation of translucency of monolithic zirconia and framework zirconia materials

    PubMed Central

    Tuncel, İlkin; Üşümez, Aslıhan

    2016-01-01

    PURPOSE The opacity of zirconia is an esthetic disadvantage that hinders achieving natural and shade-matched restorations. The aim of this study was to evaluate the translucency of non-colored and colored framework zirconia and monolithic zirconia. MATERIALS AND METHODS The three groups tested were: non-colored framework zirconia, colored framework zirconia with the A3 shade according to Vita Classic Scale, and monolithic zirconia (n=5). The specimens were fabricated in the dimensions of 15×12×0.5 mm. A spectrophotometer was used to measure the contrast ratio, which is indicative of translucency. Three measurements were made to obtain the contrast ratios of the materials over a white background (L*w) and a black background (L*b). The data were analyzed using the one-way analysis of variance and Tukey HSD tests. One specimen from each group was chosen for scanning electron microscope analysis. The determined areas of the SEM images were divided by the number of grains in order to calculate the mean grain size. RESULTS Statistically significant differences were observed among all groups (P<.05). Non-colored zirconia had the highest translucency with a contrast ratio of 0.75, while monolithic zirconia had the lowest translucency with a contrast ratio of 0.8. The mean grain sizes of the non-colored, colored, and monolithic zirconia were 233, 256, and 361 nm, respectively. CONCLUSION The translucency of the zirconia was affected by the coloring procedure and the grain size. Although monolithic zirconia may not be the best esthetic material for the anterior region, it may serve as an alternative in the posterior region for the bilayered zirconia restorations. PMID:27350851

  10. Residual Strength Analyses of Monolithic Structures

    NASA Technical Reports Server (NTRS)

    Forth, Scott (Technical Monitor); Ambur, Damodar R. (Technical Monitor); Seshadri, B. R.; Tiwari, S. N.

    2003-01-01

    Finite-element fracture simulation methodology predicts the residual strength of damaged aircraft structures. The methodology uses the critical crack-tip-opening-angle (CTOA) fracture criterion to characterize the fracture behavior of the material. The CTOA fracture criterion assumes that stable crack growth occurs when the crack-tip angle reaches a constant critical value. The use of the CTOA criterion requires an elastic- plastic, finite-element analysis. The critical CTOA value is determined by simulating fracture behavior in laboratory specimens, such as a compact specimen, to obtain the angle that best fits the observed test behavior. The critical CTOA value appears to be independent of loading, crack length, and in-plane dimensions. However, it is a function of material thickness and local crack-front constraint. Modeling the local constraint requires either a three-dimensional analysis or a two-dimensional analysis with an approximation to account for the constraint effects. In recent times as the aircraft industry is leaning towards monolithic structures with the intention of reducing part count and manufacturing cost, there has been a consistent effort at NASA Langley to extend critical CTOA based numerical methodology in the analysis of integrally-stiffened panels.In this regard, a series of fracture tests were conducted on both flat and curved aluminum alloy integrally-stiffened panels. These flat panels were subjected to uniaxial tension and during the test, applied load-crack extension, out-of-plane displacements and local deformations around the crack tip region were measured. Compact and middle-crack tension specimens were tested to determine the critical angle (wc) using three-dimensional code (ZIP3D) and the plane-strain core height (hJ using two-dimensional code (STAGS). These values were then used in the STAGS analysis to predict the fracture behavior of the integrally-stiffened panels. The analyses modeled stable tearing, buckling, and crack

  11. Spark Plasma Sintering and Multi-scale Characterization of Mesoporous Silica Disks

    NASA Astrophysics Data System (ADS)

    Maheshwari, Harsh

    Oil from shale and tight formations has helped the United States produce close to 10 million barrels of oil per day, a 40-year high. Well characterized sintered nano materials will serve as calibration materials for understanding important thermodynamic and flow properties of fluids in similar formations. To this effect, sintered mesoporous silica monoliths containing micro- and nano-porosity are characterized across multiple length scales at various processing temperatures using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Vickers hardness tests, and Brunauer-Emmett-Teller (BET) gas adsorption measurements. Results show that the mesoporosity in raw SBA-15 silica powders can be retained during spark-plasma sintering (SPS) up to 850 ºC which is lower than those achieved by conventional sintering techniques (>1050 ºC). Details of micro- and meso-porosity were revealed by studying the internal structure through SEM and in-situ TEM tomography of the sintered specimens in comparison to the pristine silica powder. The microporosity is retained up to 950°C under the same pressure, and the degree of microporosity increases when the mesopores collapse due to individual nanoparticle shrinkage. In situ TEM characterization of mesoporosity in the absence of applied pressure reveal pore collapse above 1050°C, which is considerably above the temperatures observed under applied pressures during SPS processing. The degree of microporosity, obtained under different processing conditions, is correlated to the mechanical properties, available surface area and pore morphology. In spite of the unique synthesis process, sintered mesoporous silica satisfies the Ryshkewitch relationship -- the correlation of mechanical properties to porosity. Subsequently, in-situ TEM nanoindentation was conducted to investigate the mechanical properties of individual mesoporous silica nanoparticles. The ability to control the micro- and meso-porosity of these

  12. 21 CFR 584.700 - Hydrophobic silicas.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...: (i) Amorphous fumed hydrophobic silica: Not less than 99.0 percent silicon dioxide after ignition... dichlorodimethylsilane. (ii) Precipated hydrophobic silica: Not less than 94.0 percent silicon dioxide after...

  13. 21 CFR 584.700 - Hydrophobic silicas.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...: (i) Amorphous fumed hydrophobic silica: Not less than 99.0 percent silicon dioxide after ignition... dichlorodimethylsilane. (ii) Precipated hydrophobic silica: Not less than 94.0 percent silicon dioxide after...

  14. Physisorbed Water on Silica at Mars Temperatures

    NASA Technical Reports Server (NTRS)

    Sutter, B.; Sriwatanapongse, W.; Quinn, R.; Klug, C.; Zent, A.

    2002-01-01

    The usefulness of nuclear magnetic resonance spectroscopy in probing water interactions on silica at Mars temperatures is discussed. Results indicate that two types of water occur with silica at Mars temperatures. Additional information is contained in the original extended abstract.

  15. Optothermal nonlinearity of silica aerogel

    NASA Astrophysics Data System (ADS)

    Braidotti, Maria Chiara; Gentilini, Silvia; Fleming, Adam; Samuels, Michiel C.; Di Falco, Andrea; Conti, Claudio

    2016-07-01

    We report on the characterization of silica aerogel thermal optical nonlinearity, obtained by z-scan technique. The results show that typical silica aerogels have nonlinear optical coefficient similar to that of glass (≃10-12 m2/W), with negligible optical nonlinear absorption. The nonlinear coefficient can be increased to values in the range of 10-10 m2/W by embedding an absorbing dye in the aerogel. This value is one order of magnitude higher than that observed in the pure dye and in typical highly nonlinear materials like liquid crystals.

  16. Disentangling protein-silica interactions.

    PubMed

    Giussani, Lara; Tabacchi, Gloria; Gianotti, Enrica; Coluccia, Salvatore; Fois, Ettore

    2012-03-28

    We present the results of modelling studies aimed at the understanding of the interaction of a 7 nm sized water droplet containing a negatively charged globular protein with flat silica surfaces. We show how the droplet interaction with the surface depends on the electrostatic surface charge, and that adhesion of the droplet occurs when the surface is negatively charged as well. The key role of water and of the charge-balancing counter ions in mediating the surface-protein adhesion is highlighted. The relevance of the present results with respect to the production of bioinorganic hybrids via encapsulation of proteins inside mesoporous silica materials is discussed.

  17. Silica Materials for Medical Applications

    PubMed Central

    Vallet-Regí, María; Balas, Francisco

    2008-01-01

    The two main applications of silica-based materials in medicine and biotechnology, i.e. for bone-repairing devices and for drug delivery systems, are presented and discussed. The influence of the structure and chemical composition in the final characteristics and properties of every silica-based material is also shown as a function of the both applications presented. The adequate combination of the synthesis techniques, template systems and additives leads to the development of materials that merge the bioactive behavior with the drug carrier ability. These systems could be excellent candidates as materials for the development of devices for tissue engineering. PMID:19662110

  18. Silica Precursors Derived From TEOS

    NASA Technical Reports Server (NTRS)

    Philipp, Warren H.

    1993-01-01

    Two high-char-yield polysiloxane polymers developed. Designated as TEOS-A and TEOS-B with silica char yields of 55% and 22%, respectively. These free-flowing polymers are Newtonium liquids instead of thick gels. Easily synthesized by controlled hydrolysis of inexpensive tetraethoxysilane (TEOS). Adhesive properties of TEOS-A suggest its use as binder for fabrication of ceramic articles from oxide powders. Less-viscous and more-fluid lower-molecular-weight TEOS-B used to infiltrate already-formed porous ceramic compacts to increase densities without effecting shrinkage. Also used as paint to coat substrate with silica, and to make highly pure silicate powders.

  19. Removal of dissolved and colloidal silica

    DOEpatents

    Midkiff, William S.

    2002-01-01

    Small amorphous silica particles are used to provide a relatively large surface area upon which silica will preferentially adsorb, thereby preventing or substantially reducing scaling caused by deposition of silica on evaporative cooling tower components, especially heat exchange surfaces. The silica spheres are contacted by the cooling tower water in a sidestream reactor, then separated using gravity separation, microfiltration, vacuum filtration, or other suitable separation technology. Cooling tower modifications for implementing the invention process have been designed.

  20. The properties of silica-gelatin composites

    NASA Astrophysics Data System (ADS)

    Stavinskaya, O. N.; Laguta, I. V.

    2010-06-01

    Silica-gelatin composites with various silica-to-gelatin ratios were obtained. The influence of high-dispersity silica on the swelling of composites in water and desorption of pyridoxine and thiamine vitamins incorporated into the material was studied. The addition of silica to gelatin was shown to increase the time of the dissolution of the materials in aqueous medium and decelerate the desorption of vitamins.

  1. Sonochemical coating of magnetite nanoparticles with silica.

    PubMed

    Dang, Feng; Enomoto, Naoya; Hojo, Junichi; Enpuku, Keiji

    2010-01-01

    Magnetite nanoparticles were coated with silica through the hydrolysis and condensation of tetraethyl orthosilicate (TEOS) under ultrasonic irradiation. The ultrasonic irradiation was used to prevent the agglomeration of the magnetite particles and accelerate the hydrolysis and condensation of TEOS. TEM, DLS, XRF, VSM, TG and sedimentation test were used to characterize the silica-coated magnetite particles. The dispersibility of silica-coated magnetite particles in aqueous solution was improved significantly and the agglomerate particle size was decreased to 110 nm. It was found that the agglomerate particle size of silica-coated magnetite particles was mainly decided by the coating temperature and the pH value in the silica-coating process. The weight ratio of silica in silica-coated magnetite particles was mainly decided by the pH value in the silica-coating process. The dispersibility of silica-coated magnetite particles was mainly decided by the agglomerate particle size of the suspension. The oxidation of magnetite particles in air was limited through the coated silica. The magnetism of silica-coated magnetite particles decreased slightly after silica-coating.

  2. Silica optical fibers: technology update

    NASA Astrophysics Data System (ADS)

    Krohn, David A.; McCann, Brian P.

    1995-05-01

    Silica-core optical fibers have long been the standard delivery medium for medical laser delivery systems. Their high strength, excellent flexibility, and low cost continue to make them the fiber of choice for systems operating from 300 to 2200 nm. An overview of the current fiber constructions available to the industry is reviewed. Silicone-clad fibers, hard- fluoropolymer clad fibers and silica-clad fibers are briefly compared in terms of mechanical and optical properties. The variety of fiber coatings available is also discussed. A significant product development of silica fiber delivery systems has been in side-firing laser delivery systems for Urology. These devices utilize silica-core fibers to project the laser energy at a substantial lateral angle to the conventional delivery system, typically 40 to 100 degrees off axis. Many unique distal tips have been designed to meet the needs of this potentially enormous application. There are three primary technologies employed in side-firing laser delivery systems: reflection off of an attached medium; reflection within an angle-polished fiber through total internal reflection; and reflection from both an angle-polished fiber and an outside medium. Each technology is presented and compared on the basis of operation modality, transmission efficiency, and power-handling performance.

  3. The Phagocytosis and Toxicity of Amorphous Silica

    PubMed Central

    Costantini, Lindsey M.; Gilberti, Renée M.; Knecht, David A.

    2011-01-01

    Background Inhalation of crystalline silica is known to cause an inflammatory reaction and chronic exposure leads to lung fibrosis and can progress into the disease, silicosis. Cultured macrophages bind crystalline silica particles, phagocytose them, and rapidly undergo apoptotic and necrotic death. The mechanism by which particles are bound and internalized and the reason particles are toxic is unclear. Amorphous silica has been considered to be a less toxic form, but this view is controversial. We compared the uptake and toxicity of amorphous silica to crystalline silica. Methodology/Principal Findings Amorphous silica particles are phagocytosed by macrophage cells and a single internalized particle is capable of killing a cell. Fluorescent dextran is released from endo-lysosomes within two hours after silica treatment and Caspase-3 activation occurs within 4 hours. Interestingly, toxicity is specific to macrophage cell lines. Other cell types are resistant to silica particle toxicity even though they internalize the particles. The large and uniform size of the spherical, amorphous silica particles allowed us to monitor them during the uptake process. In mCherry-actin transfected macrophages, actin rings began to form 1-3 minutes after silica binding and the actin coat disassembled rapidly following particle internalization. Pre-loading cells with fluorescent dextran allowed us to visualize the fusion of phagosomes with endosomes during internalization. These markers provided two new ways to visualize and quantify particle internalization. At 37°C the rate of amorphous silica internalization was very rapid regardless of particle coating. However, at room temperature, opsonized silica is internalized much faster than non-opsonized silica. Conclusions/Significance Our results indicate that amorphous and crystalline silica are both phagocytosed and both toxic to mouse alveolar macrophage (MH-S) cells. The pathway leading to apoptosis appears to be similar in both

  4. Uranium incorporation into amorphous silica.

    PubMed

    Massey, Michael S; Lezama-Pacheco, Juan S; Nelson, Joey M; Fendorf, Scott; Maher, Kate

    2014-01-01

    High concentrations of uranium are commonly observed in naturally occurring amorphous silica (including opal) deposits, suggesting that incorporation of U into amorphous silica may represent a natural attenuation mechanism and promising strategy for U remediation. However, the stability of uranium in opaline silicates, determined in part by the binding mechanism for U, is an important factor in its long-term fate. U may bind directly to the opaline silicate matrix, or to materials such as iron (hydr)oxides that are subsequently occluded within the opal. Here, we examine the coordination environment of U within opaline silica to elucidate incorporation mechanisms. Precipitates (with and without ferrihydrite inclusions) were synthesized from U-bearing sodium metasilicate solutions, buffered at pH ∼ 5.6. Natural and synthetic solids were analyzed with X-ray absorption spectroscopy and a suite of other techniques. In synthetic amorphous silica, U was coordinated by silicate in a double corner-sharing coordination geometry (Si at ∼ 3.8-3.9 Å) and a small amount of uranyl and silicate in a bidentate, mononuclear (edge-sharing) coordination (Si at ∼ 3.1-3.2 Å, U at ∼ 3.8-3.9 Å). In iron-bearing synthetic solids, U was adsorbed to iron (hydr)oxide, but the coordination environment also contained silicate in both edge-sharing and corner-sharing coordination. Uranium local coordination in synthetic solids is similar to that of natural U-bearing opals that retain U for millions of years. The stability and extent of U incorporation into opaline and amorphous silica represents a long-term repository for U that may provide an alternative strategy for remediation of U contamination. PMID:24984107

  5. Phase composition gradient in leached polluted cement monoliths

    SciTech Connect

    Leoni, Matteo Scardi, Paolo; Pelosato, Renato; Sora, Isabella Natali; Dotelli, Giovanni; Stampino, Paola Gallo; Presti, Arianna Lo

    2007-11-15

    The long-term behaviour of cement monoliths containing an organic waste, was investigated by means of a 14-month dynamic-leach-testing in deionised water. The degree of hydration and the phase composition were measured by Thermal Analysis (TGA/DTA), X-ray Powder Diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDXS). X-ray data, analysed by the Rietveld method, provided a detailed quantitative information on the in-depth crystalline phase distribution in the specimens. Crossed with TGA and spectroscopic data and supported by the results of kinetic/hydration calculations, the diffraction results provide a detailed description of the in-depth phase composition gradient in the leached monoliths. In particular, 14-month old specimens show a clear leaching zone with predominance of CSH and calcite near the surface and low abundance of the other usual cement constituents. The material is not completely effective in retaining the contaminant.

  6. Low-bandgap, monolithic, multi-bandgap, optoelectronic devices

    DOEpatents

    Wanlass, Mark W.; Carapella, Jeffrey J.

    2016-01-05

    Low bandgap, monolithic, multi-bandgap, optoelectronic devices (10), including PV converters, photodetectors, and LED's, have lattice-matched (LM), double-heterostructure (DH), low-bandgap GaInAs(P) subcells (22, 24) including those that are lattice-mismatched (LMM) to InP, grown on an InP substrate (26) by use of at least one graded lattice constant transition layer (20) of InAsP positioned somewhere between the InP substrate (26) and the LMM subcell(s) (22, 24). These devices are monofacial (10) or bifacial (80) and include monolithic, integrated, modules (MIMs) (190) with a plurality of voltage-matched subcell circuits (262, 264, 266, 270, 272) as well as other variations and embodiments.

  7. Mobile monolithic polymer elements for flow control in microfluidic devices

    DOEpatents

    Hasselbrink, Jr., Ernest F.; Rehm, Jason E.; Shepodd, Timothy J.

    2004-08-31

    A cast-in-place and lithographically shaped mobile, monolithic polymer element for fluid flow control in microfluidic devices and method of manufacture. Microfluid flow control devices, or microvalves that provide for control of fluid or ionic current flow can be made incorporating a cast-in-place, mobile monolithic polymer element, disposed within a microchannel, and driven by either fluid or gas pressure against a retaining or sealing surface. The polymer elements are made by the application of lithographic methods to monomer mixtures formulated in such a way that the polymer will not bond to microchannel walls. The polymer elements can seal against pressures greater than 5000 psi, and have a response time on the order of milliseconds. By the use of energetic radiation it is possible to depolymerize selected regions of the polymer element to form shapes that cannot be produced by conventional lithographic patterning and would be impossible to machine.

  8. Mobile Monolith Polymer Elements For Flow Control In Microfluidic Systems

    DOEpatents

    Hasselbrink, Jr., Ernest F.; Rehm, Jason E.; Shepodd, Timothy J.; Kirby, Brian J.

    2006-01-24

    A cast-in-place and lithographically shaped mobile, monolithic polymer element for fluid flow control in microfluidic devices and method of manufacture. Microfluid flow control devices, or microvalves that provide for control of fluid or ionic current flow can be made incorporating a cast-in-place, mobile monolithic polymer element, disposed within a microchannel, and driven by fluid pressure (either liquid or gas) against a retaining or sealing surface. The polymer elements are made by the application of lithographic methods to monomer mixtures formulated in such a way that the polymer will not bond to microchannel walls. The polymer elements can seal against pressures greater than 5000 psi, and have a response time on the order of milliseconds. By the use of energetic radiation it is possible to depolymerize selected regions of the polymer element to form shapes that cannot be produced by conventional lithographic patterning and would be impossible to machine.

  9. Mobile monolithic polymer elements for flow control in microfluidic devices

    DOEpatents

    Hasselbrink, Jr., Ernest F.; Rehm, Jason E.; Shepodd, Timothy J.; Kirby, Brian J.

    2005-11-11

    A cast-in-place and lithographically shaped mobile, monolithic polymer element for fluid flow control in microfluidic devices and method of manufacture. Microfluid flow control devices, or microvalves that provide for control of fluid or ionic current flow can be made incorporating a cast-in-place, mobile monolithic polymer element, disposed within a microchannel, and driven by fluid pressure (either liquid or gas) against a retaining or sealing surface. The polymer elements are made by the application of lithographic methods to monomer mixtures formulated in such a way that the polymer will not bond to microchannel walls. The polymer elements can seal against pressures greater than 5000 psi, and have a response time on the order of milliseconds. By the use of energetic radiation it is possible to depolymerize selected regions of the polymer element to form shapes that cannot be produced by conventional lithographic patterning and would be impossible to machine.

  10. Development of monolithically integrated silicon-film modules

    NASA Astrophysics Data System (ADS)

    Rand, J. A.; Cotter, J. E.; Ingram, A. E.; Lampros, T. H.; Ruffins, T. R.; Hall, R. B.; Barnett, A. M.

    1992-12-01

    Silicon-Film Product III is being developed into a low cost, stable device for large scale terrestrial power applications. The Product III structure is a thin (<100 μm) polycrystalline silicon layer on a non-conductive supporting ceramic substrate as illustrated in Figure 1. The presence of the substrate allows cells to be isolated and interconnected monolithically. The long term goal for the product is over 18% conversion efficiency on areas greater than 1200 cm2. The high efficiency will be based on polycrystalline thin silicon incorporated into a light trapping structure with a passivated back surface. Short term goals are focused on the development of large area ceramics, a monolithic interconnection process, and fabricating 100 cm2 solar cells.

  11. From 1D to 3D - macroscopic nanowire aerogel monoliths

    NASA Astrophysics Data System (ADS)

    Cheng, Wei; Rechberger, Felix; Niederberger, Markus

    2016-07-01

    Here we present a strategy to assemble one-dimensional nanostructures into a three-dimensional architecture with macroscopic size. With the assistance of centrifugation, we successfully gel ultrathin W18O49 nanowires with diameters of 1 to 2 nm and aspect ratios larger than 100 into 3D networks, which are transformed into monolithic aerogels by supercritical drying.Here we present a strategy to assemble one-dimensional nanostructures into a three-dimensional architecture with macroscopic size. With the assistance of centrifugation, we successfully gel ultrathin W18O49 nanowires with diameters of 1 to 2 nm and aspect ratios larger than 100 into 3D networks, which are transformed into monolithic aerogels by supercritical drying. Electronic supplementary information (ESI) available: Experimental details, SEM and TEM images, and digital photographs. See DOI: 10.1039/c6nr04429h

  12. Monolithic millimeter-wave and picosecond electronic technologies

    SciTech Connect

    Talley, W.K.; Luhmann, N.C.

    1996-03-12

    Theoretical and experimental studies into monolithic millimeter-wave and picosecond electronic technologies have been undertaken as a collaborative project between the Lawrence Livermore National Laboratory (LLNL) and the University of California Department of Applied Science Coherent Millimeter-Wave Group under the auspices of the Laboratory Directed Research and Development Program at LLNL. The work involves the design and fabrication of monolithic frequency multiplier, beam control, and imaging arrays for millimeter-wave imaging and radar, as well as the development of high speed nonlinear transmission lines for ultra-wideband radar imaging, time domain materials characterization and magnetic fusion plasma applications. In addition, the Coherent Millimeter-Wave Group is involved in the fabrication of a state-of-the-art X-band ({approximately}8-11 GHz) RF photoinjector source aimed at producing psec high brightness electron bunches for advanced accelerator and coherent radiation generation studies.

  13. Hydrogenation with monolith reactor under conditions of immiscible liquid phases

    SciTech Connect

    Nordquist, Andrew Francis; Wilhelm, Frederick Carl; Waller, Francis Joseph; Machado, Reinaldo Mario

    2002-01-01

    The present invention relates to an improved for the hydrogenation of an immiscible mixture of an organic reactant in water. The immiscible mixture can result from the generation of water by the hydrogenation reaction itself or, by the addition of, water to the reactant prior to contact with the catalyst. The improvement resides in effecting the hydrogenation reaction in a monolith catalytic reactor from 100 to 800 cpi, at a superficial velocity of from 0.1 to 2 m/second in the absence of a cosolvent for the immiscible mixture. In a preferred embodiment, the hydrogenation is carried out using a monolith support which has a polymer network/carbon coating onto which a transition metal is deposited.

  14. Low-bandgap, monolithic, multi-bandgap, optoelectronic devices

    DOEpatents

    Wanlass, Mark W.; Carapella, Jeffrey J.

    2016-03-22

    Low bandgap, monolithic, multi-bandgap, optoelectronic devices (10), including PV converters, photodetectors, and LED's, have lattice-matched (LM), double-heterostructure (DH), low-bandgap GaInAs(P) subcells (22, 24) including those that are lattice-mismatched (LMM) to InP, grown on an InP substrate (26) by use of at least one graded lattice constant transition layer (20) of InAsP positioned somewhere between the InP substrate (26) and the LMM subcell(s) (22, 24). These devices are monofacial (10) or bifacial (80) and include monolithic, integrated, modules (MIMs) (190) with a plurality of voltage-matched subcell circuits (262, 264, 266, 270, 272) as well as other variations and embodiments.

  15. Low-bandgap, monolithic, multi-bandgap, optoelectronic devices

    DOEpatents

    Wanlass, Mark W.; Carapella, Jeffrey J.

    2014-07-08

    Low bandgap, monolithic, multi-bandgap, optoelectronic devices (10), including PV converters, photodetectors, and LED's, have lattice-matched (LM), double-heterostructure (DH), low-bandgap GaInAs(P) subcells (22, 24) including those that are lattice-mismatched (LMM) to InP, grown on an InP substrate (26) by use of at least one graded lattice constant transition layer (20) of InAsP positioned somewhere between the InP substrate (26) and the LMM subcell(s) (22, 24). These devices are monofacial (10) or bifacial (80) and include monolithic, integrated, modules (MIMs) (190) with a plurality of voltage-matched subcell circuits (262, 264, 266, 270, 272) as well as other variations and embodiments.

  16. Production of aligned microfibers and nanofibers and derived functional monoliths

    DOEpatents

    Hu, Michael Z.; DePaoli, David W.; Kuritz, Tanya; Omatete, Ogbemi

    2007-08-14

    The present invention comprises a method for producing microfibers and nanofibers and further fabricating derived solid monolithic materials having aligned uniform micro- or nanofibrils. A method for producing fibers ranging in diameter from micrometer-sized to nanometer-sized comprises the steps of producing an electric field and preparing a solid precipitative reaction media wherein the media comprises at least one chemical reactive precursor and a solvent having low electrical conductivity and wherein a solid precipitation reaction process for nucleation and growth of a solid phase occurs within the media. Then, subjecting the media to the electric field to induce in-situ growth of microfibers or nanofibers during the reaction process within the media causing precipitative growth of solid phase particles wherein the reaction conditions and reaction kinetics control the size, morphology and composition of the fibers. The fibers can then be wet pressed while under electric field into a solid monolith slab, dried and consolidated.

  17. Design and Testing of Prototypic Elements Containing Monolithic Fuel

    SciTech Connect

    N.E. Woolstenhulme; M.K. Meyer; D.M. Wachs

    2011-10-01

    The US fuel development team has performed numerous irradiation tests on small to medium sized specimens containing low enriched uranium fuel designs. The team is now focused on qualification and demonstration of the uranium-molybdenum Base Monolithic Design and has entered the next generation of testing with the design and irradiation of prototypic elements which contain this fuel. The designs of fuel elements containing monolithic fuel, such as AFIP-7 (which is currently under irradiation) and RERTR-FE (which is currently under fabrication), are appropriate progressions relative to the technology life cycle. The culmination of this testing program will occur with the design, fabrication, and irradiation of demonstration products to include the base fuel demonstration and design demonstration experiments. Future plans show that design, fabrication, and testing activities will apply the rigor needed for a demonstration campaign.

  18. Radially polarized cylindrical vector beams from a monolithic microchip laser

    NASA Astrophysics Data System (ADS)

    Naidoo, Darryl; Fromager, Michael; Ait-Ameur, Kamel; Forbes, Andrew

    2015-11-01

    Monolithic microchip lasers consist of a thin slice of laser crystal where the cavity mirrors are deposited directly onto the end faces. While this property makes such lasers very compact and robust, it prohibits the use of intracavity laser beam shaping techniques to produce complex light fields. We overcome this limitation and demonstrate the selection of complex light fields in the form of vector-vortex beams directly from a monolithic microchip laser. We employ pump reshaping and a thermal gradient across the crystal surface to control both the intensity and polarization profile of the output mode. In particular, we show laser oscillation on a superposition of Laguerre-Gaussian modes of zero radial and nonzero azimuthal index in both the scalar and vector regimes. Such complex light fields created directly from the source could find applications in fiber injection, materials processing and in simulating quantum processes.

  19. Affinity Monolith-Integrated Microchips for Protein Purification and Concentration.

    PubMed

    Gao, Changlu; Sun, Xiuhua; Wang, Huaixin; Qiao, Wei; Hu, Bo

    2016-01-01

    Affinity chromatography is a valuable method to purify and concentrate minute amount of proteins. Monoliths with epoxy groups for affinity immobilization were prepared by direct in-situ photopolymerization of glycidyl methacrylate and ethylene glycol dimethacrylate in porogenic solvents consisting of 1-dodecanol and cyclohexanol. By integrating affinity monoliths onto a microfluidic system, targeted biomolecules can be captured and retained on affinity column, while other biomolecules having no specific interactions toward the immobilized ligands flow through the microchannel. Therefore, proteins which remain on the affinity column are purified and concentrated, and then eluted by appropriate solutions and finally, separated by microchip capillary electrophoresis. This integrated microfluidic device has been applied to the purification and separation of specific proteins (FITC-labeled human serum albumin and IgG) in a mixture.

  20. Affinity Monolith-Integrated Microchips for Protein Purification and Concentration.

    PubMed

    Gao, Changlu; Sun, Xiuhua; Wang, Huaixin; Qiao, Wei; Hu, Bo

    2016-01-01

    Affinity chromatography is a valuable method to purify and concentrate minute amount of proteins. Monoliths with epoxy groups for affinity immobilization were prepared by direct in-situ photopolymerization of glycidyl methacrylate and ethylene glycol dimethacrylate in porogenic solvents consisting of 1-dodecanol and cyclohexanol. By integrating affinity monoliths onto a microfluidic system, targeted biomolecules can be captured and retained on affinity column, while other biomolecules having no specific interactions toward the immobilized ligands flow through the microchannel. Therefore, proteins which remain on the affinity column are purified and concentrated, and then eluted by appropriate solutions and finally, separated by microchip capillary electrophoresis. This integrated microfluidic device has been applied to the purification and separation of specific proteins (FITC-labeled human serum albumin and IgG) in a mixture. PMID:27473483

  1. Encapsulated subwavelength grating as a quasi-monolithic resonant reflector.

    PubMed

    Brückner, Frank; Friedrich, Daniel; Britzger, Michael; Clausnitzer, Tina; Burmeister, Oliver; Kley, Ernst-Bernhard; Danzmann, Karsten; Tünnermann, Andreas; Schnabel, Roman

    2009-12-21

    For a variety of laser interferometric experiments, the thermal noise of high-reflectivity multilayer dielectric coatings limits the measurement sensitivity. Recently, monolithic high-reflection waveguide mirrors with nanostructured surfaces have been proposed to reduce the thermal noise in interferometric measurements. Drawbacks of this approach are a highly complicated fabrication process and the high susceptibility of the nanostructured surfaces to damage and pollution. Here, we propose and demonstrate a novel quasi-monolithic resonant surface reflector that also avoids the thick dielectric stack of conventional mirrors but has a flat and robust surface. Our reflector is an encapsulated subwavelength grating that is based on silicon. We measured a high reflectivity of 93% for a wavelength of lambda = 1.55 microm under normal incidence. Perfect reflectivities are possible in theory.

  2. Stretchable Superhydrophobicity from Monolithic, Three-Dimensional Hierarchical Wrinkles.

    PubMed

    Lee, Won-Kyu; Jung, Woo-Bin; Nagel, Sidney R; Odom, Teri W

    2016-06-01

    We report the design of three-dimensional (3D) hierarchical wrinkle substrates that can maintain their superhydrophobicity even after being repeatedly stretched. Monolithic poly(dimethysiloxane) with multiscale features showed wetting properties characteristic of static superhydrophobicity with water contact angles (>160°) and very low contact angle hysteresis (<5°). To examine how superhydrophobicity was maintained as the substrate was stretched, we investigated the dynamic wetting behavior of bouncing and splashing upon droplet impact with the surface. On hierarchical wrinkles consisting of three different length scales, superhydrophobic bouncing was observed. The substrate remained superhydrophobic up to 100% stretching with no structural defects after 1000 cycles of stretching and releasing. Stretchable superhydrophobicity was possible because of the monolithic nature of the hierarchical wrinkles as well as partial preservation of nanoscale structures under stretching. PMID:27144774

  3. Stretchable Superhydrophobicity from Monolithic, Three-Dimensional Hierarchical Wrinkles.

    PubMed

    Lee, Won-Kyu; Jung, Woo-Bin; Nagel, Sidney R; Odom, Teri W

    2016-06-01

    We report the design of three-dimensional (3D) hierarchical wrinkle substrates that can maintain their superhydrophobicity even after being repeatedly stretched. Monolithic poly(dimethysiloxane) with multiscale features showed wetting properties characteristic of static superhydrophobicity with water contact angles (>160°) and very low contact angle hysteresis (<5°). To examine how superhydrophobicity was maintained as the substrate was stretched, we investigated the dynamic wetting behavior of bouncing and splashing upon droplet impact with the surface. On hierarchical wrinkles consisting of three different length scales, superhydrophobic bouncing was observed. The substrate remained superhydrophobic up to 100% stretching with no structural defects after 1000 cycles of stretching and releasing. Stretchable superhydrophobicity was possible because of the monolithic nature of the hierarchical wrinkles as well as partial preservation of nanoscale structures under stretching.

  4. A virtual zero-time, monolithic systolic sorting array

    SciTech Connect

    Britton, C.L.; Ericson, M.N.; Bouldin, D.W.

    1989-01-01

    A virtual zero-time monolithic sorting chip is described. The chip has a systolic array architecture and implements the ''sinking sort'' algorithm. The basic functional module of the systolic array is detailed and development techniques employed as well as functional simulation and results are presented. Lessons learned and educational significance of the development of this chip at a university are discussed. 3 refs., 4 figs.

  5. A virtual zero-time, monolithic systolic sorting array

    SciTech Connect

    Britton, C.L. Jr.; Ericson, M.N.; Bouldin, D.W.; Tennessee Univ., Knoxville, TN )

    1990-01-01

    A virtual zero-time monolithic sorting chip is described. The chip has a systolic array architecture and implements the sinking sort'' algorithm. The basic functional module of the systolic array is detailed and development techniques employed as well as functional simulation and results are presented. Lessons learned and educational significance of the development of this chip at a university are discussed. 3 refs., 4 figs.

  6. Monolithic AlGaAs second-harmonic nanoantennas

    NASA Astrophysics Data System (ADS)

    Gili, V. F.; Carletti, L.; Locatelli, A.; Rocco, D.; Finazzi, M.; Ghirardini, L.; Favero, I.; Gomez, C.; Lemaître, A.; Celebrano, M.; De Angelis, C.; Leo, G.

    2016-07-01

    We demonstrate monolithic aluminum gallium arsenide (AlGaAs) optical anoantennas. Using a selective oxidation technique, we fabricate such epitaxial semiconductor nanoparticles on an aluminum oxide substrate. Second harmonic generation from an AlGaAs nanocylinder of height h=400 nm and varying radius pumped with femtosecond pulses delivered at 1554-nm wavelength has been measured, revealing a peak conversion efficiency exceeding 10-5 for nanocylinders with an otpimized geometry.

  7. Low frequency, high sensitive tunable mechanical monolithic horizontal sensors

    NASA Astrophysics Data System (ADS)

    Acernese, Fausto; De Rosa, Rosario; Giordano, Gerardo; Romano, Rocco; Vilasi, Silvia; Barone, Fabrizio

    2011-04-01

    This paper describes an optimized version of the mechanical version of the monolithic tunable folded pendulum, developed at the University of Salerno, configurable both as seismometer and, in a force-feedback configuration, as accelerometer. Typical application of the sensors are in the field of geophysics, including the study of seismic and newtonian noise for characterization of suitable sites for underground interferometer for gravitational waves detection. The sensor, shaped with precision machining and electric-discharge-machining, like the previous version, is a very compact instrument, very sensitive in the low-frequency seismic noise band, with a very good immunity to environmental noises. Important characteristics are the tunability of the resonance frequency and the integrated laser optical readout, consisting of an optical lever and an interferometer. The theoretical sensitivity curves, largely improved due to a new design of the pendulum arms and of the electronics, are in a very good agreement with the measurements. The very large measurement band (10-6 +/- 10Hz) is couple to a very good sensitivity (10-12 m/√Hz in the band 0.1 +/- 10Hz), as seismometer. Prototypes of monolithic seismometers are already operational in selected sites around the world both to acquire seismic data for scientific analysis of seismic noise and to collect all the useful information to understand their performances in the very low frequency band (f < 1mHz). The results of the monolithic sensor as accelerometer (force feed-back configuration) are also presented and discussed. Particular relevance has their sensitivity that is better than 10-11 m/s2/√Hz in the band 0.1 +/- 10Hz. Finally, hypotheses are made on further developments and improvements of monolithic sensors.

  8. Advanced on-chip divider for monolithic microwave VCO's

    NASA Technical Reports Server (NTRS)

    Peterson, Weddell C.

    1989-01-01

    High frequency division on a monolithic circuit is a critical technology required to significantly enhance the performance of microwave and millimeter-wave phase-locked sources. The approach used to meet this need is to apply circuit design practices which are essentially 'microwave' in nature to the basically 'digital' problem of high speed division. Following investigation of several promising circuit approaches, program phase 1 culminated in the design and layout of an 8.5 GHz (Deep Space Channel 14) divide by four circuit based on a dynamic mixing divider circuit approach. Therefore, during program phase 2, an 8.5 GHz VCO with an integral divider which provides a phase coherent 2.125 GHz reference signal for phase locking applications was fabricated and optimized. Complete phase locked operation of the monolithic GaAs devices (VCO, power splitter, and dynamic divider) was demonstrated both individually and as an integrated unit. The fully functional integrated unit in a suitable test fixture was delivered to NASA for engineering data correlation. Based on the experience gained from this 8.5 GHz super component, a monolithic GaAs millimeter-wave dynamic divider for operation with an external VCO was also designed, fabricated, and characterized. This circuit, which was also delivered to NASA, demonstrated coherent division by four at an input frequency of 24.3 GHz. The high performance monolithic microwave VCO with a coherent low frequency reference output described in this report and others based on this technology will greatly benefit advanced communications systems in both the DoD and commercial sectors. Signal processing and instrumentation systems based on phase-locking loops will also attain enhanced performance at potentially reduced cost.

  9. Clinical assessment of enamel wear caused by monolithic zirconia crowns.

    PubMed

    Stober, T; Bermejo, J L; Schwindling, F S; Schmitter, M

    2016-08-01

    The purpose of this study was to measure enamel wear caused by antagonistic monolithic zirconia crowns and to compare this with enamel wear caused by contralateral natural antagonists. Twenty monolithic zirconia full molar crowns were placed in 20 patients. Patients with high activity of the masseter muscle at night (bruxism) were excluded. For analysis of wear, vinylpolysiloxane impressions were prepared after crown incorporation and at 6-, 12-, and 24-month follow-up. Wear of the occlusal contact areas of the crowns, of their natural antagonists, and of two contralateral natural antagonists (control teeth) was measured by use of plaster replicas and a 3D laser-scanning device. Differences of wear between the zirconia crown antagonists and the control teeth were investigated by means of two-sided paired Student's t-tests and linear regression analysis. After 2 years, mean vertical loss was 46 μm for enamel opposed to zirconia, 19-26 μm for contralateral control teeth and 14 μm for zirconia crowns. Maximum vertical loss was 151 μm for enamel opposed to zirconia, 75-115 μm for control teeth and 60 μm for zirconia crowns. Statistical analysis revealed significant differences between wear of enamel by zirconia-opposed teeth and by control teeth. Gender, which significantly affected wear, was identified as a possible confounder. Monolithic zirconia crowns generated more wear of opposed enamel than did natural teeth. Because of the greater wear caused by other dental ceramics, the use of monolithic zirconia crowns may be justified.

  10. Advanced indium antimonide monolithic charge coupled infrared imaging arrays

    NASA Technical Reports Server (NTRS)

    Koch, T. L.; Merilainen, C. A.; Thom, R. D.

    1981-01-01

    The continued process development of SiO2 insulators for use in advanced InSb monolithic charge coupled infrared imaging arrays is described. Specific investigations into the use of plasma enhanced chemical vapor deposited (PECVD) SiO2 as a gate insulator for InSb charge coupled devices is discussed, as are investigations of other chemical vapor deposited SiO2 materials.

  11. Foil fabrication and barrier layer application for monolithic fuels

    SciTech Connect

    Moore, Glenn A. Clark, Curtis R.; Jue, J.-F.; Swank, W. David; Haggard, D.C.; Chapple, Michael D.; Burkes, Douglas E.

    2008-07-15

    This presentation provides details of recent UMo fuel developments efforts at the Idaho National Laboratory. Processing of monolithic fuel foil, the friction bonding process, and hot isostatic press (HIP) sample preparation will be presented. Details of the hot rolling, foil annealing, zirconium barrier-layer application to U10Mo fuel foils via the hot-rolling process and application of silicon rich aluminum interfacial-layers via a thermal spray process will be presented. (author)

  12. Monolithic AlGaAs second-harmonic nanoantennas.

    PubMed

    Gili, V F; Carletti, L; Locatelli, A; Rocco, D; Finazzi, M; Ghirardini, L; Favero, I; Gomez, C; Lemaître, A; Celebrano, M; De Angelis, C; Leo, G

    2016-07-11

    We demonstrate monolithic aluminum gallium arsenide (AlGaAs) optical nanoantennas. Using a selective oxidation technique, we fabricated epitaxial semiconductor nanocylinders on an aluminum oxide substrate. Second harmonic generation from AlGaAs nanocylinders of 400 nm height and varying radius pumped with femtosecond pulses delivered at 1554-nm wavelength has been measured, revealing a peak conversion efficiency exceeding 10-5 for nanocylinders with an optimized geometry. PMID:27410864

  13. Monolithic torpedo bottle lining at Weirton Steel Corporation

    SciTech Connect

    Baker, R.; Griffith, E.

    1996-12-31

    In late 1992 and early 1993 Weirton Steel burned through three torpedo bottles in a three-month period. To determine the cause of the burn throughs, a thorough review of bottle maintenance practices was initiated. Upon identification of contributing factors, changes in operating practices were made. In an effort to increase bottle reliability, lining trials were initiated. Among the trials, a monolithic lining was installed and this paper will discuss results of the lining to date.

  14. Monolithic microwave integrated circuits: Interconnections and packaging considerations

    NASA Technical Reports Server (NTRS)

    Bhasin, K. B.; Downey, A. N.; Ponchak, G. E.; Romanofsky, R. R.; Anzic, G.; Connolly, D. J.

    1984-01-01

    Monolithic microwave integrated circuits (MMIC's) above 18 GHz were developed because of important potential system benefits in cost reliability, reproducibility, and control of circuit parameters. The importance of interconnection and packaging techniques that do not compromise these MMIC virtues is emphasized. Currently available microwave transmission media are evaluated to determine their suitability for MMIC interconnections. An antipodal finline type of microstrip waveguide transition's performance is presented. Packaging requirements for MMIC's are discussed for thermal, mechanical, and electrical parameters for optimum desired performance.

  15. Monolithic microwave integrated circuit technology for advanced space communication

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Romanofsky, Robert R.

    1988-01-01

    Future Space Communications subsystems will utilize GaAs Monolithic Microwave Integrated Circuits (MMIC's) to reduce volume, weight, and cost and to enhance system reliability. Recent advances in GaAs MMIC technology have led to high-performance devices which show promise for insertion into these next generation systems. The status and development of a number of these devices operating from Ku through Ka band will be discussed along with anticipated potential applications.

  16. Coherent optical monolithic phased-array antenna steering system

    DOEpatents

    Hietala, Vincent M.; Kravitz, Stanley H.; Vawter, Gregory A.

    1994-01-01

    An optical-based RF beam steering system for phased-array antennas comprising a photonic integrated circuit (PIC). The system is based on optical heterodyning employed to produce microwave phase shifting by a monolithic PIC constructed entirely of passive components. Microwave power and control signal distribution to the antenna is accomplished by optical fiber, permitting physical separation of the PIC and its control functions from the antenna. The system reduces size, weight, complexity, and cost of phased-array antenna systems.

  17. Laser cathode-ray tube with a monolithic laser screen

    SciTech Connect

    Bondarev, V Yu; Kozlovskii, V I; Krysa, A B; Popov, Yu M; Sviridov, D E; Skasyrskii, Ya K

    2007-09-30

    A monolithic nanostructure containing 13 GaInP/AlGaInP quantum wells between two Bragg mirrors formed by AlGaAs/AlAs layers is grown by vapour-phase epitaxy from organometallic compounds. A laser with longitudinal pumping by a scanning electron-beam is developed on the basis of this structure. An output power of 8 W is achieved at a wavelength of 660 nm with an efficiency of 7.5% at room temperature. (lasers)

  18. Fabrication and characterization of aligned macroporous monolith for high-performance protein chromatography.

    PubMed

    Du, Kaifeng; Zhang, Qi; Dan, Shunmin; Yang, Min; Zhang, Yongkui; Chai, Dezhi

    2016-04-22

    In the present study, a freeze casting method combined with particle accumulation was applied to fabricate the aligned macroporous monolith for high-performance protein chromatography. For the preparation, the reactive colloids were first prepared by using glycidyl methacrylate and ethylene glycol dimethacrylate as monomers. Subsequently, these colloids accumulated regularly and polymerized into the aligned macroporous monolith. The aligned porous structure of the monolith was characterized by SEM, mercury intrusion, and flow hydrodynamics. The results revealed that the generated monolith was possessed of aligned macropores in size of about 10 μm and high column permeability. Finally, after being modified with sulfonated groups, the monolith was evaluated for its chromatographic performance. It demonstrated that the aligned macropores endowed the monolith with excellent adsorption capacity and high column efficiency. PMID:27016114

  19. [Preparation of a novel polymer monolith using atom transfer radical polymerization method for solid phase extraction].

    PubMed

    Shen, Ying; Qi, Li; Qiao, Juan; Mao, Lanqun; Chen, Yi

    2013-04-01

    In this study, a novel polymer monolith based solid phase extraction (SPE) material has been prepared by two-step atom transfer radical polymerization (ATRP) method. Firstly, employing ethylene glycol dimethacrylate (EDMA) as a cross-linker, a polymer monolith filled in a filter head has been in-situ prepared quickly under mild conditions. Then, the activators generated by electron transfer ATRP (ARGET ATRP) was used for the modification of poly(2-(dimethylamino)ethyl-methacrylate) (PDMAEMA) on the monolithic surface. Finally, this synthesized monolith for SPE was successfully applied in the extraction and enrichment of steroids. The results revealed that ATRP can be developed as a facile and effective method with mild reaction conditions for monolith construction and has the potential for preparing monolith in diverse devices.

  20. Pepsin immobilization on an aldehyde-modified polymethacrylate monolith and its application for protein analysis.

    PubMed

    Han, Wenjuan; Yamauchi, Mika; Hasegawa, Urara; Noda, Masanori; Fukui, Kiichi; van der Vlies, André J; Uchiyama, Susumu; Uyama, Hiroshi

    2015-05-01

    Polymer-based monoliths with interconnected porous structure have attracted much attention as a high-performance stationary phase for online digestion liquid chromatography-mass spectrometry (LC-MS) system. In this study, a poly(glycidyl methacrylate-co-methyl methacrylate) (PGM) monolith prepared via thermally induced phase separation (TIPS) was used as a solid support to covalently immobilize pepsin. The PGM monolith was modified with aminoacetal to yield an aldehyde-bearing (PGM-CHO) monolith. Pepsin was immobilized onto the PGM-CHO monolith via reductive amination. The immobilized pepsin showed better pH and thermal stability compared with free pepsin. Furthermore, the PGM-CHO monolith modified with pepsin was applied for online protein digestion followed by LC-MS and LC-MS/MS analyses. As a result, a larger number of peptides are reproducibly identified compared to those by polystyrene/divinylbenzene particle (POROS)-based online pepsin column.

  1. Fabrication and characterization of aligned macroporous monolith for high-performance protein chromatography.

    PubMed

    Du, Kaifeng; Zhang, Qi; Dan, Shunmin; Yang, Min; Zhang, Yongkui; Chai, Dezhi

    2016-04-22

    In the present study, a freeze casting method combined with particle accumulation was applied to fabricate the aligned macroporous monolith for high-performance protein chromatography. For the preparation, the reactive colloids were first prepared by using glycidyl methacrylate and ethylene glycol dimethacrylate as monomers. Subsequently, these colloids accumulated regularly and polymerized into the aligned macroporous monolith. The aligned porous structure of the monolith was characterized by SEM, mercury intrusion, and flow hydrodynamics. The results revealed that the generated monolith was possessed of aligned macropores in size of about 10 μm and high column permeability. Finally, after being modified with sulfonated groups, the monolith was evaluated for its chromatographic performance. It demonstrated that the aligned macropores endowed the monolith with excellent adsorption capacity and high column efficiency.

  2. Organic monoliths for hydrophilic interaction electrochromatography/chromatography and immunoaffinity chromatography

    PubMed Central

    Gunasena, Dilani N.; El Rassi, Ziad

    2012-01-01

    This article is aimed at providing a review of the progress made over the past decade in the preparation of polar monoliths for hydrophilic interaction liquid chromatography (HILIC)/capillary electrochromatography (HI-CEC) and in the design of immuno-monoliths for immunoaffinity chromatography (IAC) that are based on some of the polar monolith precursors used in HILIC/HI-CEC. In addition, this review article discusses some of the applications of polar monoliths by HILIC and HI-CEC, and the applications of immuno-monoliths. This article is by no means an exhaustive review of the literature; it is rather a survey of the recent progress made in the field with 83 references published in the past decade on the topics of HILIC and IAC monoliths. PMID:22147366

  3. Preparation of a biomimetic polyphosphorylcholine monolithic column for immobilized artificial membrane chromatography.

    PubMed

    Zhao, XiangLong; Chen, WeiJia; Zhou, ZhengYin; Wang, QiQin; Liu, ZhengHua; Moaddel, Ruin; Jiang, ZhengJin

    2015-08-14

    The present work aims to prepare a novel phosphatidylcholine functionalized monolithic stationary phase by in situ co-polymerization of 12-methacryloyl dodecylphosphocholine (MDPC) and ethylene dimethacrylate (EDMA) for immobilized artificial membrane chromatography. Scanning electron microscopy, energy dispersive X-ray spectroscopy, FT-IR spectroscopy, pore size distribution analysis, ζ-potential analysis and micro-HPLC were used to evaluate the monolithic structure and physicochemical properties. Satisfactory morphology, high mechanical stability, good permeability and chromatographic performance were obtained on the optimized monolithic columns. A typical reverse-phase retention mechanism was observed over a wide range of organic solvent content (acetonitrile< 80%). The optimized poly(MDPC-co-EDMA) monolith exhibited good selectivity for proteins and basic drugs. Good correlation was observed between the retention on commercial IAM column (IAM.PC.DD2) and poly(MDPC-co-EDMA) monolith. This novel poly(MDPC-co-EDMA) monolith exhibited good potential for studying the drug-membrane interaction.

  4. Advanced Gasification Mercury/Trace Metal Control with Monolith Traps

    SciTech Connect

    Michael L. Swanson; Grant E. Dunham; Mark A. Musich

    2007-02-01

    Three potential additives for controlling mercury emissions from syngas at temperatures ranging from 350 to 500 F (177 to 260 C) were developed. Current efforts are being directed at increasing the effective working temperature for these sorbents and also being able to either eliminate any potential mercury desorption or trying to engineer a trace metal removal system that can utilize the observed desorption process to repeatedly regenerate the same sorbent monolith for extended use. Project results also indicate that one of these same sorbents can also successfully be utilized for arsenic removal. Capture of the hydrogen selenide in the passivated tubing at elevated temperatures has resulted in limited results on the effective control of hydrogen selenide with these current sorbents, although lower-temperature results are promising. Preliminary economic analysis suggests that these Corning monoliths potentially could be more cost-effective than the conventional cold-gas (presulfided activated carbon beds) technology currently being utilized. Recent Hg-loading results might suggest that the annualized costs might be as high as 2.5 times the cost of the conventional technology. However, this annualized cost does not take into account the significantly improved thermal efficiency of any plant utilizing the warm-gas monolith technology currently being developed.

  5. Three-Dimensional Bicontinuous Graphene Monolith from Polymer Templates.

    PubMed

    Liu, Kewei; Chen, Yu-Ming; Policastro, Gina M; Becker, Matthew L; Zhu, Yu

    2015-06-23

    The two-dimensional single-layer and few-layered graphene exhibit many attractive properties such as large specific surface area and high charge carrier mobility. However, graphene sheets tend to stack together and form aggregates, which do not possess the desirable properties associated with graphene. Herein, we report a method to fabricate three-dimensional (3D), bicontinuous graphene monolith through a versatile hollow nickel (Ni) template derived from polymer blends. The poly(styrene)/poly(ethylene oxide) were used to fabricate a bicontinuous gyroid template using controlled phase separation. The Ni template was formed by electroless metal depositing on the polymer followed by removing the polymer phase. The resulting hollow Ni structure was highly porous (95.2%). Graphene was then synthesized from this hollow Ni template using chemical vapor deposition and the free-standing bicontinuous graphene monolith was obtained in high-throughput process. Finally, the bicontinuous graphene monolith was used directly as binder-free electrode in supercapacitor applications. The supercapacitor devices exhibited excellent stability.

  6. UPDATE ON MECHANICAL ANALYSIS OF MONOLITHIC FUEL PLATES

    SciTech Connect

    D. E. Burkes; F. J. Rice; J.-F. Jue; N. P. Hallinan

    2008-03-01

    Results on the relative bond strength of the fuel-clad interface in monolithic fuel plates have been presented at previous RRFM conferences. An understanding of mechanical properties of the fuel, cladding, and fuel / cladding interface has been identified as an important area of investigation and quantification for qualification of monolithic fuel forms. Significant progress has been made in the area of mechanical analysis of the monolithic fuel plates, including mechanical property determination of fuel foils, cladding processed by both hot isostatic pressing and friction bonding, and the fuel-clad composite. In addition, mechanical analysis of fabrication induced residual stress has been initiated, along with a study to address how such stress can be relieved prior to irradiation. Results of destructive examinations and mechanical tests are presented along with analysis and supporting conclusions. A brief discussion of alternative non-destructive evaluation techniques to quantify not only bond quality, but also bond integrity and strength, will also be provided. These are all necessary steps to link out-of-pile observations as a function of fabrication with in-pile behaviours.

  7. Monolithic preamplifier employing epitaxial N-channel JFETs

    SciTech Connect

    Radeka, V.; Rescia, S. ); Manfredi, P.F.; Re, V.; Speziali, V. . Dipt. di Elettronica Istituto Nazionale di Fisica Nucleare, Milan )

    1992-02-01

    This paper reports the results obtained in the research program oriented to the realisation of a monolithic preamplifier for calorimetry applications at high luminosity colliders. The main purpose of the program is to arrive at a monolithic realisation with a performance as close as possible to that of discrete preamplifiers. The junction field-effect transistors employed in discrete preamplifiers have an epitaxial channel and a very heavily doped gate diffused onto it. They present the best noise and radiation tolerance characteristics. The first step in the program implementation was, accordingly, the search for a process able to make the integration of epitaxial-channel. JFETs on a monolithic substrate possible. The integration has been accomplished on the basis of a buried-layer approach to device isolation. Individual JFETs and a complete preamplifier employing only N-channel JFETs have been realised. The characterisation of the individual devices has shown that their behaviour in terms of small signal and noise parameters is very close to that of their discrete equivalents. This result, along with the very good noise performances of the preamplifier, seems to point out that the buried layer process has fulfilled the task for which it was developed.

  8. Monolithic pixels on moderate resistivity substrate and sparsifying readout architecture

    NASA Astrophysics Data System (ADS)

    Giubilato, P.; Battaglia, M.; Bisello, D.; Caselle, M.; Chalmet, P.; Demaria, L.; Ikemoto, Y.; Kloukinas, K.; Mansuy, S. C.; Mattiazzo, S.; Marchioro, A.; Mugnier, H.; Pantano, D.; Potenza, A.; Rivetti, A.; Rousset, J.; Silvestrin, L.; Snoeys, W.

    2013-12-01

    The LePix projects aim realizing a new generation monolithic pixel detectors with improved performances at lesser cost with respect to both current state of the art monolithic and hybrid pixel sensors. The detector is built in a 90 nm CMOS process on a substrate of moderate resistivity. This allows charge collection by drift while maintaining the other advantages usually offered by MAPS, like having a single piece detector and using a standard CMOS production line. The collection by drift mechanism, coupled to the low capacitance design of the collecting node made possible by the monolithic approach, provides an excellent signal to noise ratio straight at the pixel cell together with a radiation tolerance far superior to conventional un-depleted MAPS. The excellent signal-to-noise performance is demonstrated by the device ability to separate the 6 keV 55Fe double peak at room temperature. To achieve high granularity (10-20 μm pitch pixels) over large detector areas maintaining high readout speed, a completely new compressing architecture has been devised. This architecture departs from the mainstream hybrid pixel sparsification approach, which uses in-pixel logic to reduce data, by using topological compression to minimize pixel area and power consumption.

  9. Effect of cements on fracture resistance of monolithic zirconia crowns

    PubMed Central

    Nakamura, Keisuke; Mouhat, Mathieu; Nergård, John Magnus; Lægreid, Solveig Jenssen; Kanno, Taro; Milleding, Percy; Örtengren, Ulf

    2016-01-01

    Abstract Objectives The present study investigated the effect of cements on fracture resistance of monolithic zirconia crowns in relation to their compressive strength. Materials and methods Four different cements were tested: zinc phosphate cement (ZPC), glass-ionomer cement (GIC), self-adhesive resin-based cement (SRC) and resin-based cement (RC). RC was used in both dual cure mode (RC-D) and chemical cure mode (RC-C). First, the compressive strength of each cement was tested according to a standard (ISO 9917-1:2004). Second, load-to-failure test was performed to analyze the crown fracture resistance. CAD/CAM-produced monolithic zirconia crowns with a minimal thickness of 0.5 mm were prepared and cemented to dies with each cement. The crown–die samples were loaded until fracture. Results The compressive strength of SRC, RC-D and RC-C was significantly higher than those of ZPC and GIC (p < 0.05). However, there was no significant difference in the fracture load of the crown between the groups. Conclusion The values achieved in the load-to-failure test suggest that monolithic zirconia crowns with a minimal thickness of 0.5 mm may have good resistance against fracture regardless of types of cements. PMID:27335900

  10. Monolithic poly(N-vinylcarbazole-co-1,4-divinylbenzene) capillary columns for the separation of biomolecules.

    PubMed

    Koeck, Rainer; Bakry, Rania; Tessadri, Richard; Bonn, Guenther K

    2013-09-01

    Monolithic capillary columns were prepared by thermally initiated free radical copolymerization of N-vinylcarbazole (NVC) and 1,4-divinylbenzene (DVB) within the confines of 200 and 100 μm i.d. fused silica capillaries. The reaction was carried out under the influence of inert micro-(toluene) and macroporogen (1-decanol) and α,α'-azoisobutyronitrile (AIBN) as a free radical initiator. The material proved high mechanical stability applying water and acetonitrile as mobile phases. The morphological and porous properties were studied by scanning electron microscopy (SEM), nitrogen sorption (BET) and mercury intrusion porosimetry (MIP). The homogeneity of the copolymerization process was confirmed by elemental analysis and monomer conversion measurements. The newly developed NVC/DVB monolithic supports showed high separation efficiency towards biomolecules, applying reversed-phase (RP) and ion-pair reversed-phase (IP-RP) separation modes, which is exemplified by the separations of peptides, proteins and oligonucleotides. Furthermore the maximum loading capacity was evaluated. The chromatographic performance under isocratic elution was determined in terms of theoretical plate number and plate height, where up to 41,000 plates per column and a minimum plate height value of 1.7 μm were achieved, applying oligonucleotide separations. In gradient elution mode, peak capacities of 96 and 127 were achieved within a gradient time window of 60 min for protein and oligonucleotide separations, respectively. The material proved to have high permeability, good repeatability of the fabrication process and high surface areas in the range of 120-160 m(2) g(-1). PMID:23799449

  11. Effect of Silica Fume on two-stage Concrete Strength

    NASA Astrophysics Data System (ADS)

    Abdelgader, H. S.; El-Baden, A. S.

    2015-11-01

    Two-stage concrete (TSC) is an innovative concrete that does not require vibration for placing and compaction. TSC is a simple concept; it is made using the same basic constituents as traditional concrete: cement, coarse aggregate, sand and water as well as mineral and chemical admixtures. As its name suggests, it is produced through a two-stage process. Firstly washed coarse aggregate is placed into the formwork in-situ. Later a specifically designed self compacting grout is introduced into the form from the lowest point under gravity pressure to fill the voids, cementing the aggregate into a monolith. The hardened concrete is dense, homogeneous and has in general improved engineering properties and durability. This paper presents the results from a research work attempt to study the effect of silica fume (SF) and superplasticizers admixtures (SP) on compressive and tensile strength of TSC using various combinations of water to cement ratio (w/c) and cement to sand ratio (c/s). Thirty six concrete mixes with different grout constituents were tested. From each mix twenty four standard cylinder samples of size (150mm×300mm) of concrete containing crushed aggregate were produced. The tested samples were made from combinations of w/c equal to: 0.45, 0.55 and 0.85, and three c/s of values: 0.5, 1 and 1.5. Silica fume was added at a dosage of 6% of weight of cement, while superplasticizer was added at a dosage of 2% of cement weight. Results indicated that both tensile and compressive strength of TSC can be statistically derived as a function of w/c and c/s with good correlation coefficients. The basic principle of traditional concrete, which says that an increase in water/cement ratio will lead to a reduction in compressive strength, was shown to hold true for TSC specimens tested. Using a combination of both silica fume and superplasticisers caused a significant increase in strength relative to control mixes.

  12. Nanostructuring an erbium local environment inside sol-gel silica glasses: toward efficient erbium optical fiber lasers

    NASA Astrophysics Data System (ADS)

    Savelii, Inna; El Hamzaoui, Hicham; Bigot, Laurent; Bouwmans, Géraud; Fsaifes, Ihsan; Capoen, Bruno; Bouazaoui, Mohamed

    2016-02-01

    To extend the use of erbium- (Er-)/aluminum- (Al-) codoped optical fibers in hostile environments, the reduction of the Al amount has been identified as a serious way to harden them against harsh radiation. In this work, sol-gel monolithic Er3+-doped and Er3+/Al3+-codoped silica glasses were prepared from nanoporous silica xerogels soaked in a solution containing an Er salt together or not with an Al salt. After sintering, these glasses were used as the core material of microstructured optical fibers made by the stack-and-draw method. The influence of Al incorporation on the optical properties of Er3+-doped silica glasses and fibers is investigated. This approach enabled the preparation of silica glasses containing dispersed Er3+ ions with low Al content. The obtained fibers have been tested in an all-fibered cavity laser architecture. The Er3+/Al3+-codoped fiber laser presents a maximum efficiency of 27% at 1530 nm. We show that without Al doping, the laser exhibits lower performances that depend on Er content inside the doped fiber core. The effect of Er pair-induced quenching also has been investigated through nonsaturable absorption experiments, which clearly indicate that the fraction of Er ion pairs is significantly reduced in the Al-codoped fiber.

  13. Photoinitiated grafting of porous polymer monoliths and thermoplastic polymers for microfluidic devices

    DOEpatents

    Frechet, Jean M. J.; Svec, Frantisek; Rohr, Thomas

    2008-10-07

    A microfluidic device preferably made of a thermoplastic polymer that includes a channel or a multiplicity of channels whose surfaces are modified by photografting. The device further includes a porous polymer monolith prepared via UV initiated polymerization within the channel, and functionalization of the pore surface of the monolith using photografting. Processes for making such surface modifications of thermoplastic polymers and porous polymer monoliths are set forth.

  14. Application of Monolithic Zirconia Ceramics in Dental Practice: A Case History Report.

    PubMed

    Kim, Hee-Kyung; Kim, Sung-Hun; Lee, Jai-Bong; Han, Jung-Suk; Yeo, In-Sung

    2016-01-01

    Monolithic zirconia restorations increasingly have been used in dental practice in recent years and demonstrate superior mechanical performance compared with porcelain-veneered zirconia restorations. Recent advances in manufacturing technology have made possible the fabrication of translucent monolithic zirconia ceramics. This case report describes three clinical examples of monolithic zirconia fixed dental prostheses being used in the anterior and posterior regions and exhibiting acceptable esthetic results. PMID:27611758

  15. Application of Monolithic Zirconia Ceramics in Dental Practice: A Case History Report.

    PubMed

    Kim, Hee-Kyung; Kim, Sung-Hun; Lee, Jai-Bong; Han, Jung-Suk; Yeo, In-Sung

    2016-01-01

    Monolithic zirconia restorations increasingly have been used in dental practice in recent years and demonstrate superior mechanical performance compared with porcelain-veneered zirconia restorations. Recent advances in manufacturing technology have made possible the fabrication of translucent monolithic zirconia ceramics. This case report describes three clinical examples of monolithic zirconia fixed dental prostheses being used in the anterior and posterior regions and exhibiting acceptable esthetic results.

  16. Silica Lubrication in Faults (Invited)

    NASA Astrophysics Data System (ADS)

    Rowe, C. D.; Rempe, M.; Lamothe, K.; Kirkpatrick, J. D.; White, J. C.; Mitchell, T. M.; Andrews, M.; Di Toro, G.

    2013-12-01

    Silica-rich rocks are common in the crust, so silica lubrication may be important for causing fault weakening during earthquakes if the phenomenon occurs in nature. In laboratory friction experiments on chert, dramatic shear weakening has been attributed to amorphization and attraction of water from atmospheric humidity to form a 'silica gel'. Few observations of the slip surfaces have been reported, and the details of weakening mechanism(s) remain enigmatic. Therefore, no criteria exist on which to make comparisons of experimental materials to natural faults. We performed a series of friction experiments, characterized the materials formed on the sliding surface, and compared these to a geological fault in the same rock type. Experiments were performed in the presence of room humidity at 2.5 MPa normal stress with 3 and 30 m total displacement for a variety of slip rates (10-4 - 10-1 m/s). The friction coefficient (μ) reduced from >0.6 to ~0.2 at 10-1 m/s, but only fell to ~0.4 at 10-2 - 10-4 m/s. The slip surfaces and wear material were observed using laser confocal Raman microscopy, electron microprobe, X-ray diffraction, and transmission electron microscopy. Experiments at 10-1 m/s formed wear material consisting of ≤1 μm powder that is aggregated into irregular 5-20 μm clumps. Some material disaggregated during analysis with electron beams and lasers, suggesting hydrous and unstable components. Compressed powder forms smooth pavements on the surface in which grains are not visible (if present, they are <100 nm). Powder contains amorphous material and as yet unidentified crystalline and non-crystalline forms of silica (not quartz), while the worn chert surface underneath shows Raman spectra consistent with a mixture of quartz and amorphous material. If silica amorphization facilitates shear weakening in natural faults, similar wear materials should be formed, and we may be able to identify them through microstructural studies. However, the sub

  17. Feasibility evaluation of the monolithic braided ablative nozzle

    NASA Astrophysics Data System (ADS)

    Director, Mark N.; McPherson, Douglass J., Sr.

    1992-02-01

    The feasibility of the monolithic braided ablative nozzle was evaluated as part of an independent research and development (IR&D) program complementary to the National Aeronautics and Space Administration/Marshall Space Flight Center (NASA/MSFC) Low-Cost, High-Reliability Case, Insulation and Nozzle for Large Solid Rocket Motors (LOCCIN) Program. The monolithic braided ablative nozzle is a new concept that utilizes a continuous, ablative, monolithic flame surface that extends from the nozzle entrance, through the throat, to the exit plane. The flame surface is fabricated using a Through-the-Thickness braided carbon-fiber preform, which is impregnated with a phenolic or phenolic-like resin. During operation, the braided-carbon fiber/resin material ablates, leaving the structural backside at temperatures which are sufficiently low to preclude the need for any additional insulative materials. The monolithic braided nozzle derives its potential for low life cycle cost through the use of automated processing, one-component fabrication, low material scrap, low process scrap, inexpensive raw materials, and simplified case attachment. It also has the potential for high reliability because its construction prevents delamination, has no nozzle bondlines or leak paths along the flame surface, is amenable to simplified analysis, and is readily inspectable. In addition, the braided construction has inherent toughness and is damage-tolerant. Two static-firing tests were conducted using subscale, 1.8 - 2.0-inch throat diameter, hardware. Tests were approximately 15 seconds in duration, using a conventional 18 percent aluminum/ammonium perchlorate propellant. The first of these tests evaluated the braided ablative as an integral backside insulator and exit cone; the second test evaluated the monolithic braided ablative as an integral entrance/throat/exit cone nozzle. Both tests met their objectives. Radial ablation rates at the throat were as predicted, approximately 0.017 in

  18. Comparison of perfusion media and monoliths for protein and virus-like particle chromatography.

    PubMed

    Wu, Yige; Abraham, Dicky; Carta, Giorgio

    2016-05-20

    Structural and performance characteristics of perfusion chromatography media (POROS HS 20 and 50) and those of a polymethacrylate monolith (CIM SO3-1 tube monolith column) are compared for protein and virus-like particle chromatography using 1mL columns. Axial flow columns are used for POROS while the monolith has a radial flow configuration, which provides comparable operating pressures. The POROS beads contain a bimodal distribution of pore sizes, some as large as 0.5μm, which allow a small fraction of the mobile phase to flow within the particles, while the monolith contains 1-2μm flow channels. For proteins (lysozyme and IgG), the dynamic binding capacity of the POROS columns is more than twice that of the monolith at longer residence times. While the DBC of the POROS HS 50 column decreases at shorter residence times, the DBC of the POROS HS 20 column for IgG remains nearly twice that of the monolith at residence times at least as low as 0.2min as a result of intraparticle convection. Protein recoveries are comparable for all three columns. For VLPs, however, the eluted peaks are broader and recovery is lower for the monolith than for the POROS columns and is dependent on the direction of flow in the monolith, which is attributed to denser layer observed by SEM at the inlet surface of the monolith that appears to trap VLPs when loading in the normal flow direction. PMID:27106397

  19. A poly(vinyl alcohol)/sodium alginate blend monolith with nanoscale porous structure.

    PubMed

    Sun, Xiaoxia; Uyama, Hiroshi

    2013-10-04

    A stimuli-responsive poly(vinyl alcohol) (PVA)/sodium alginate (SA) blend monolith with nanoscale porous (mesoporous) structure is successfully fabricated by thermally impacted non-solvent induced phase separation (TINIPS) method. The PVA/SA blend monolith with different SA contents is conveniently fabricated in an aqueous methanol without any templates. The solvent suitable for the fabrication of the present blend monolith by TINIPS is different with that of the PVA monolith. The nanostructural control of the blend monolith is readily achieved by optimizing the fabrication conditions. Brunauer Emmett Teller measurement shows that the obtained blend monolith has a large surface area. Pore size distribution plot for the blend monolith obtained by the non-local density functional theory method reveals the existence of the nanoscale porous structure. Fourier transform infrared analysis reveals the strong interactions between PVA and SA. The pH-responsive property of the blend monolith is investigated on the basis of swelling ratio in different pH solutions. The present blend monolith of biocompatible and biodegradable PVA and SA with nanoscale porous structure has large potential for applications in biomedical and environmental fields.

  20. Preparation of a boronate-functionalized affinity hybrid monolith for specific capture of glycoproteins.

    PubMed

    Yang, F; Mao, J; He, X W; Chen, L X; Zhang, Y K

    2013-06-01

    A novel strategy for preparation of a boronate affinity hybrid monolith was developed using a Cu(I)-catalyzed 1,3-dipolar azide-alkyne cycloaddition (CuAAC) reaction of an alkyne-boronate ligand with an azide-functionalized monolithic intermediate. An azide-functionalized hybrid monolith was first synthesized via a single-step procedure to provide reactive sites for click chemistry; then the alkyne-boronate ligands were covalently immobilized on the azide-functionalized hybrid monolith via an in-column CuAAC reaction to form a boronate affinity hybrid monolith under mild conditions. The boronate affinity monolith was characterized and evaluated by means of elemental analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. The boronate affinity hybrid monolith exhibited excellent specificity toward nucleosides and glycoproteins, which were chosen as test cis-diol-containing compounds under neutral conditions. The binding capacity of the monolith for the glycoprotein ovalbumin was 2.36 mg · g(-1) at pH 7.0. The practicability of the boronate affinity hybrid monolithic material was demonstrated by specific capture of the glycoproteins ovalbumin and ovotransferrin from an egg sample.