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Sample records for gel culture final

  1. Maintenance of Bacterial Cultures on Anhydrous Silica Gel

    ERIC Educational Resources Information Center

    Lennox, John E.

    1977-01-01

    Suspensions of 20 different cultures were grown on appropriate media, then pipetted into sterile anhydrous silica gel. Silica gel cultures after incubation and refrigerated storage were tested for viability. Results showed little mutation, low replication, low contamination, minimal expenses, and survival up to two years. (CS)

  2. Fluoride glasses from sol gels. Final report

    SciTech Connect

    Uhlmann, D.R.

    1986-09-15

    The use of sol-gel coatings to strengthen oxide glasses was demonstrated for the case of fused silica. Increases in strength to as much as 2.2 times the strength of uncoated glass were obtained. The strengthening does not involve the annealing of surface microcracks, but rather the filling-in of such flaws. The strengthening does not depend on coating thickness over the range 2000-10000 Angstroms, but does depend significantly upon the state of hydrolysis of the substrate surface.

  3. A thixotropic nanocomposite gel for three-dimensional cell culture

    NASA Astrophysics Data System (ADS)

    Pek, Y. Shona; Wan, Andrew C. A.; Shekaran, Asha; Zhuo, Lang; Ying, Jackie Y.

    2008-11-01

    Thixotropic materials, which become less viscous under stress and return to their original state when stress is removed, have been used to deliver gel-cell constructs and therapeutic agents. Here we show that a polymer-silica nanocomposite thixotropic gel can be used as a three-dimensional cell culture material. The gel liquefies when vortexed-allowing cells and biological components to be added-and resolidifies to trap the components when the shear force from spinning is removed. Good permeability of nutrients and gases through the gel allows various cell types to proliferate and be viable for up to three weeks. Human mesenchymal stem cells cultured in stiffer gels developed bone-like behaviour, showing that the rheological properties of the gel can control cell differentiation. No enzymatic, chemical, or photo-crosslinking, changes in ionic strength or temperature are required to form or liquefy the gel, offering a way to sub-culture cells without using trypsin-a protease commonly used in traditional cell culture techniques.

  4. Gel entrapment culture of rat hepatocytes for investigation of tetracycline-induced toxicity.

    PubMed

    Shen, Chong; Meng, Qin; Schmelzer, Eva; Bader, Augustinus

    2009-07-15

    This paper aimed to explore three-dimensionally cultured hepatocytes for testing drug-induced nonalcoholic steatohepatitis. Gel entrapped rat hepatocytes were applied for investigation of the tetracycline-induced steatohepatitis, while hepatocyte monolayer was set as a control. The toxic responses of hepatocytes were systematically evaluated by measuring cell viability, liver-specific function, lipid accumulation, oxidative stress, adenosine triphosphate content and mitochondrial membrane potential. The results suggested that gel entrapped hepatocytes showed cell death after 96 h of tetracycline treatment at 25 muM which is equivalent to toxic serum concentration in rats, while hepatocyte monolayer showed cell death at a high dose of 200 muM. The concentration-dependent accumulation of lipid as well as mitochondrial damage were regarded as two early events for tetracycline hepatotoxicity in gel entrapment culture due to their detectability ahead of subsequent increase of oxidative stress and a final cell death. Furthermore, the potent protection of fenofibrate and fructose-1,6-diphosphate were evidenced in only gel entrapment culture with higher expressions on the genes related to beta-oxidation than hepatocyte monolayer, suggesting the mediation of lipid metabolism and mitochondrial damage in tetracycline toxicity. Overall, gel entrapped hepatocytes in three-dimension reflected more of the tetracycline toxicity in vivo than hepatocyte monolayer and thus was suggested as a more relevant system for evaluating steatogenic drugs. PMID:19463838

  5. Gel entrapment culture of rat hepatocytes for investigation of tetracycline-induced toxicity

    SciTech Connect

    Shen Chong; Meng Qin Schmelzer, Eva; Bader, Augustinus

    2009-07-15

    This paper aimed to explore three-dimensionally cultured hepatocytes for testing drug-induced nonalcoholic steatohepatitis. Gel entrapped rat hepatocytes were applied for investigation of the tetracycline-induced steatohepatitis, while hepatocyte monolayer was set as a control. The toxic responses of hepatocytes were systematically evaluated by measuring cell viability, liver-specific function, lipid accumulation, oxidative stress, adenosine triphosphate content and mitochondrial membrane potential. The results suggested that gel entrapped hepatocytes showed cell death after 96 h of tetracycline treatment at 25 {mu}M which is equivalent to toxic serum concentration in rats, while hepatocyte monolayer showed cell death at a high dose of 200 {mu}M. The concentration-dependent accumulation of lipid as well as mitochondrial damage were regarded as two early events for tetracycline hepatotoxicity in gel entrapment culture due to their detectability ahead of subsequent increase of oxidative stress and a final cell death. Furthermore, the potent protection of fenofibrate and fructose-1,6-diphosphate were evidenced in only gel entrapment culture with higher expressions on the genes related to {beta}-oxidation than hepatocyte monolayer, suggesting the mediation of lipid metabolism and mitochondrial damage in tetracycline toxicity. Overall, gel entrapped hepatocytes in three-dimension reflected more of the tetracycline toxicity in vivo than hepatocyte monolayer and thus was suggested as a more relevant system for evaluating steatogenic drugs.

  6. Micelle, microemulsions, and gels for the conservation of cultural heritage.

    PubMed

    Baglioni, Piero; Berti, Debora; Bonini, Massimo; Carretti, Emiliano; Dei, Luigi; Fratini, Emiliano; Giorgi, Rodorico

    2014-03-01

    Past restorations performed with acrylic and vinyl polymers showed detrimental effects to wall paintings that lead to the complete disfiguration of the painted surfaces. The removal of these materials performed with the traditional solvent-based methodology represents a real challenge to conservators and usually achieves very poor results. This review reports on the new palette, nowadays available to restorers, based on microemulsions, micellar systems, physical and chemical gels specifically formulated for the cleaning of cultural heritage artefacts. These systems have been developed in the last twenty years within the cultural framework of colloids and surface science. PMID:24200088

  7. Thermally reversible colloidal gels for three-dimensional chondrocyte culture

    PubMed Central

    Lapworth, James W.; Hatton, Paul V.; Goodchild, Rebecca L.; Rimmer, Stephen

    2012-01-01

    Healthy cells are required in large numbers to form a tissue-engineered construct and primary cells must therefore be increased in number in a process termed ‘expansion’. There are significant problems with existing procedures, including cell injury and an associated loss of phenotype, but three-dimensional culture has been reported to offer a solution. Reversible gels, which allow for the recovery of cells after expansion would therefore have great value in the expansion of chondrocytes for tissue engineering applications, but they have received relatively little attention to date. In this study, we examined the synthesis and use of thermoresponsive polymers that form reversible three-dimensional gels for chondrocyte cell culture. A series of polymers comprising N-isopropylacrylamide (NIPAM) and styrene was synthesized before studying their thermoresponsive solution behaviour and gelation. A poly(NIPAM-co-styrene-graft-N-vinylpyrrolidone) variant was also synthesized in order to provide increased water content. Both random- and graft-copolymers formed particulate gels above the lower critical solution temperature and, on cooling, re-dissolved to allow enzyme-free cell recovery. Chondrocytes remained viable in all of these materials for 24 days, increased in number and produced collagen type II and glycosaminoglycans. PMID:21775322

  8. Functional properties of human thyroid follicles cultured within collagen gel.

    PubMed

    Massart, C; Hody, B; Condé, D; Leclech, G; Edan, G; Nicol, M

    1988-04-01

    Cultures of human thyroid follicles embedded in collagen gel were performed to investigate certain functional properties under bovine thyrotropin (TSH) stimulation. Follicles obtained from normal glands responded to increasing concentrations of TSH administered on day 4 in culture and for 3 days by increased amounts of cyclic AMP (cAMP), thyroglobulin (Tg) and triiodothyronine (T3) and by decreased levels of thyroxine (T4). Effect was maximal at 2000 microU/ml TSH (cAMP) or 200 microU/ml (Tg, T3, T4). When methimazole or propylthiouracil (PTU) were added, the T3 levels decreased. Follicle lumens contained a periodic acid-Schiff substance which was identified by immunoreaction as Tg. Thyroid follicles obtained from Graves' disease glands gave modified results with an earlier and intensified T3 response and no increase in Tg. These data show that (1) Tg and T3 are secretory products of functional follicles giving a cAMP-mediated response to TSH. (2) The detected T3 also derives from T4 5'-deiodination inhibited by PTU. (3) Intensified T3 response in Graves' follicles is probably due to enhanced conversion of T4 to T3. PMID:2836248

  9. Dewatering fine coal slurries by gel extraction. Final report

    SciTech Connect

    Gehrke, S.H.; Lyu, Lii-Hurng

    1990-12-31

    A new technology called gel extraction has been evaluated to determine its economic viability in dewatering the fine and ultrafine coal slurries generated upon separation of sulfur and ash from clean coal during the physical coal cleaning process. Water must be removed from such slurries prior to transportation and combustion but the dewatering costs are substantial, especially for the fine particles below 28 mesh (0.6 mm). Gel extraction is a potential breakthrough in slurry dewatering technology. The goal of this project was to acquire the qualitative and quantitative data needed to estimate the potential of gel extraction for dewatering coal slurries. The specific objectives were to determine the maximum extents of dewatering (minimum surface moisture in the coal product), the clarity of the water removed (minimum solids content), the speed of the dewatering cycles, the service lifetime of the gels, and the factors which influence all of these. With the results obtained, an economic analysis of Ohio coal cleaning plant dewatering technologies was carried out. The polymer gel at the heart of this project, poly (N-isopropylacrylamide) (PNIPA), can swell several times its shrunken weight at 32{degrees}C by absorbing water at 25{degrees}C. In gel extraction, a shrunken NIPA gel is contacted with a slurry at ambient temperature or cooler; the gel swells by absorbing water from the slurry. The gel is then removed from the dewatered slurry and warmed above its critical temperature of 33{degrees}C, which returns it to the shrunken state by releasing the absorbed water. The facts that the gel is reusable and the process is simple and driven by low-grade energy (warm temperatures), and not inherently limited by particle size, made the process an attractive possible alternative to centrifugation, screening, filtration, etc. for slurry dewatering.

  10. Interaction of electromagnetic fields with chondrocytes in gel culture

    NASA Astrophysics Data System (ADS)

    Grodzinsky, Alan J.; Buschmann, Michael D.; Gluzband, Yehezkiel A.

    1992-01-01

    The specific objectives of this research period were: (1) to quantify the effect of applied electric fields on chondrocyte metabolism, using a range of stimulation frequencies and amplitudes; (2) to compare the chondrocyte biosynthetic response to applied fields at early times in agarose gel culture before an extracellular matrix has accumulated and at later times after significant deposition of matrix around and between the cells; and (3) to begin to interpret the biosynthetic response to applied fields in terms of models of physical mechanisms. The results of these studies suggest that electric fields applied to chondrocytes in agarose can modulate the synthesis of proteoglycans and protein constituents. Biosynthesis may be inhibited or stimulated depending on the amplitude of the applied current density. In addition, the presence of extracellular matrix may enhance the ability of normal chondrocytes and cells in intact cartilage to respond to electric fields, although the presence of matrix was not required for the stimulatory response to be observed with Swarm rat chondrosarcoma cells.

  11. Extraction and assembly of tissue-derived gels for cell culture and tissue engineering.

    PubMed

    Uriel, Shiri; Labay, Edwardine; Francis-Sedlak, Megan; Moya, Monica L; Weichselbaum, Ralph R; Ervin, Natalia; Cankova, Zdravka; Brey, Eric M

    2009-09-01

    Interactions with the extracellular matrix (ECM) play an important role in regulating cell function. Cells cultured in, or on, three-dimensional ECM recapitulate similar features to those found in vivo that are not present in traditional two-dimensional culture. In addition, both natural and synthetic materials containing ECM components have shown promise in a number of tissue engineering applications. Current materials available for cell culture and tissue engineering do not adequately reflect the diversity of ECM composition between tissues. In this paper, a method is presented for extracting solutions of proteins and glycoproteins from soft tissues and inducing assembly of these proteins into gels. The extracts contain ECM proteins specific to the tissue source with low levels of intracellular molecules. Gels formed from the tissue-derived extracts have nanostructure similar to ECM in vivo and can be used to culture cells as both a thin substrate coating and a thick gel. This technique could be used to assemble hydrogels with varying composition depending upon the tissue source, hydrogels for three-dimensional culture, as scaffolds for tissue engineering therapies, and to study cell-matrix interactions. PMID:19115821

  12. Extraction and Assembly of Tissue-Derived Gels for Cell Culture and Tissue Engineering

    PubMed Central

    Uriel, Shiri; Labay, Edwardine; Francis-Sedlak, Megan; Moya, Monica L.; Weichselbaum, Ralph R.; Ervin, Natalia; Cankova, Zdravka

    2009-01-01

    Interactions with the extracellular matrix (ECM) play an important role in regulating cell function. Cells cultured in, or on, three-dimensional ECM recapitulate similar features to those found in vivo that are not present in traditional two-dimensional culture. In addition, both natural and synthetic materials containing ECM components have shown promise in a number of tissue engineering applications. Current materials available for cell culture and tissue engineering do not adequately reflect the diversity of ECM composition between tissues. In this paper, a method is presented for extracting solutions of proteins and glycoproteins from soft tissues and inducing assembly of these proteins into gels. The extracts contain ECM proteins specific to the tissue source with low levels of intracellular molecules. Gels formed from the tissue-derived extracts have nanostructure similar to ECM in vivo and can be used to culture cells as both a thin substrate coating and a thick gel. This technique could be used to assemble hydrogels with varying composition depending upon the tissue source, hydrogels for three-dimensional culture, as scaffolds for tissue engineering therapies, and to study cell–matrix interactions. PMID:19115821

  13. [Bacteriostatic and/or bactericidal extract of Aloe vera gel on cultures of Listeria monocytogenes].

    PubMed

    Ramírez Mérida, Luis Guillermo; Morón de Salim, Alba; Catinella, Rosangela; Castillo, Luis

    2012-03-01

    Listeria monocytogenes is a bacteria responsible for food borne diseases (FBD). The effect of Aloe vera gel extract as a possible bacteriostatic and/or bactericidal against Listeria monocytogenes, was checked by determined the minimum inhibitory concentration (MIC), the time of minimum inhibition (TMI) and minimum bactericidal concentration (MBC) solutions extract of Aloe vera gel in different concentrations on cultures of Listeria monocytogenes ATCC 7635. We applied the agar diffusion method, using solutions of extract of Aloe vera gel at concentrations of 0 to 100% for the MIC. The TMI was determined by growth curves in trypticase soy broth with an initial inoculum of Listeria monocytogenes ATCC 7635 of 108 CFU/mL in each solution. It was determined that the MIC was 10% extract of Aloe vera gel and TMI was 5 hours at concentrations of 10%, 20% and 30% of Aloe vera, while concentrations of 50, 80, 90 and 100%, the time was 8 hours. It was found that indeed the Aloe vera gel is bacteriostatic power on Listeria monocytogenes (p < 0.001), but yet, no bactericidal effect was obtained in our study. PMID:23477211

  14. Varying the counter ion changes the kinetics, but not the final structure of colloidal gels.

    PubMed

    Zhang, Li; Mikhailovskaya, Alesya; Constantin, Doru; Foffi, Giuseppe; Tavacoli, Joseph; Schmitt, Julien; Muller, François; Rochas, Cyrille; Wang, Nan; Langevin, Dominique; Salonen, Anniina

    2016-02-01

    We show that, while the gelation of colloidal silica proceeds much faster in the presence of added KCl than NaCl, the final gels are very similar in structure and properties. We have studied the gelation process by visual inspection and by small angle X-ray scattering for a range of salt and silica particle concentrations. The characteristic times of the early aggregation process and the formation of a stress-bearing structure with both salts are shown to collapse onto master curves with single multiplicative constants, linked to the stability ratio of the colloidal suspensions. The influence of the salt type and concentration is confirmed to be mainly kinetic, as the static structure factors and viscoelastic moduli of the gels are shown to be equivalent at normalized times. While there is strong variation in the kinetics, the structure and properties of the gel at long-times are shown to be mainly controlled by the concentration of particles, and hardly influenced by the type or the concentration of salt. This suggests that the differences between gels generated by different salts are only transient in time. PMID:26520820

  15. Nearly Finished Genomes Produced Using Gel Microdroplet Culturing (Seventh Annual Sequencing, Finishing, Analysis in the Future (SFAF) Meeting 2012)

    ScienceCinema

    Fitzsimmons, Michael [LANL

    2013-01-25

    Michael Fitzsimmons from Los Alamos National Laboratory gives a talk titled "Nearly Finished Genomes Produced Using Gel Microdroplet Culturing" at the 7th Annual Sequencing, Finishing, Analysis in the Future (SFAF) Meeting held in June, 2012 in Santa Fe, NM.

  16. Characterization of collagen gel solutions and collagen matrices for cell culture.

    PubMed

    Sheu, M T; Huang, J C; Yeh, G C; Ho, H O

    2001-07-01

    The influence of glutaraldehyde as a crosslinking agent to increase the strength of collagen matrices for cell culture was examined in this study. Collagen solutions of 1% were treated with different concentrations (0-0.2%) of glutaraldehyde for 24 h. The viscoelasticity of the resulting collagen gel solution was measured using dynamic mechanical analysis (DMA), which demonstrated that all collagen gel solutions examined followed the same model pattern. The creep compliance model of Voigt-Kelvin satisfactorily described the change of viscoelasticity expressed by these collagen gel solutions. These crosslinked collagen gel solutions were freeze-dried to form a matrix with a thickness of about 0.2-0.3 mm. The break modulus of these collagen matrices measured by DMA revealed that the higher the degree of crosslinking. the higher the break modulus. The compatibility of fibroblasts isolated from nude mouse skin with these collagen matrices was found to be acceptable at a cell density of 3 x 10(5) cells/cm2 with no contraction, even when using a concentration of glutaraldehyde of up to 0.2%. PMID:11396874

  17. Responsive hydrogels produced via organic sol-gel chemistry for cell culture applications.

    PubMed

    Patil, Smruti; Chaudhury, Pulkit; Clarizia, Lisa; McDonald, Melisenda; Reynaud, Emmanuelle; Gaines, Peter; Schmidt, Daniel F

    2012-08-01

    In this study, we report the synthesis of novel environmentally responsive polyurea hydrogel networks prepared via organic sol-gel chemistry and demonstrate that the networks can stabilize pH while releasing glucose both in simple aqueous media and in mammalian cell culture settings. Hydrogel formulations have been developed based on the combination of an aliphatic triisocyanate with pH-insensitive amine functional polyether and pH-sensitive poly(ethyleneimine) segments in a minimally toxic solvent suitable for the sol-gel reaction. The polyether component of the polyurea network is sufficiently hydrophilic to give rise to some level of swelling independent of environmental pH, while the poly(ethyleneimine) component contains tertiary amine groups providing pH sensitivity to the network in the form of enhanced swelling and release under acidic conditions. The reaction of these materials to form a network is rapid and requires no catalyst. The resultant material exhibits the desired pH-responsive swelling behavior and demonstrates its ability to simultaneously neutralize lactic acid and release glucose in both cell-free culture media and mammalian cell culture, with no detectable evidence of cytotoxicity or changes in cell behavior, in the case of either SA-13 human hybridomas or mouse embryonic stem cells. Furthermore, pH is observed to have a clear effect on the rate at which glucose is released from the hydrogel network. Such characteristics promise to maintain a favorable cell culture environment in the absence of human intervention. PMID:22561670

  18. Disulfide-Based Diblock Copolymer Worm Gels: A Wholly-Synthetic Thermoreversible 3D Matrix for Sheet-Based Cultures.

    PubMed

    Simon, Karen A; Warren, Nicholas J; Mosadegh, Bobak; Mohammady, Marym R; Whitesides, George M; Armes, Steven P

    2015-12-14

    It is well-known that 3D in vitro cell cultures provide a much better model than 2D cell cultures for understanding the in vivo microenvironment of cells. However, significant technical challenges in handling and analyzing 3D cell cultures remain, which currently limits their widespread application. Herein, we demonstrate the application of wholly synthetic thermoresponsive block copolymer worms in sheet-based 3D cell culture. These worms form a soft, free-standing gel reversibly at 20-37 °C, which can be rapidly converted into a free-flowing dispersion of spheres on cooling to 5 °C. Functionalization of the worms with disulfide groups was found to be essential for ensuring sufficient mechanical stability of these hydrogels to enable long-term cell culture. These disulfide groups are conveniently introduced via statistical copolymerization of a disulfide-based dimethacrylate under conditions that favor intramolecular cyclization and subsequent thiol/disulfide exchange leads to the formation of reversible covalent bonds between adjacent worms within the gel. This new approach enables cells to be embedded within micrometer-thick slabs of gel with good viability, permits cell culture for at least 12 days, and facilitates recovery of viable cells from the gel simply by incubating the culture in buffer at 4 °C (thus, avoiding the enzymatic degradation required for cell harvesting when using commercial protein-based gels, such as Matrigel). PMID:26509930

  19. Cyclic traction machine for long-term culture of fibroblast-populated collagen gels.

    PubMed

    Langelier, E; Rancourt, D; Bouchard, S; Lord, C; Stevens, P P; Germain, L; Auger, F A

    1999-01-01

    Our research group has been investigating the effect of cyclic deformations on the evolution of fibroblast populated collagen gels (FPCG). Since existing traction machines are not designed for such an application, we had to design a cyclic traction machine adapted to tissue culture inside an incubator over an extended period of time. Biocompatible materials were used for fabrication to allow for easy sterilization and to prevent any adverse reaction from the tissue. The traction machine is based on a computer-controlled stepping motor system for easy adjustment of the deformation amplitude and frequency. The maximum stretching speed achieved is around 1 mm/s. The traction machine can measure FPCG mechanical properties and perform rupture tests to determine its ultimate strength. Several FPCGs have been successfully cultured with the machine for up to four weeks without any adverse reaction. PMID:9916762

  20. OPTICA: Our Path Together Initiating Cultural Access. Final Report.

    ERIC Educational Resources Information Center

    Jackson, Susan, Comp.

    This final report describes the activities and outcomes of OPTICA (Our Path Together Initiating Cultural Access) programs. For each program an information sheet indicates the goal, total participation, status of the goal, and activities of the program. Programs included: (1) Hands On: ASL Creative Story Telling, a program that used children's…

  1. 78 FR 27419 - Final Safety Culture Policy Statement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-10

    ...The Bureau of Safety and Environmental Enforcement (BSEE) issues this Final Statement of Policy to announce its expectation that individuals and organizations performing or overseeing activities regulated by BSEE establish and maintain a positive safety culture commensurate with the significance of their activities and the nature and complexity of their organizations and functions. The BSEE......

  2. Characterization of Mannheimia haemolytica in beef calves via nasopharyngeal culture and pulsed-field gel electrophoresis.

    PubMed

    Capik, Sarah F; White, Brad J; Lubbers, Brian V; Apley, Michael D; Mosier, Derek A; Larson, Robert L; Murray, Robert W

    2015-09-01

    Mannheimia haemolytica is a major bacterial component of bovine respiratory disease (BRD); unfortunately, very little is known about M. haemolytica transmission dynamics among cattle. Identifying potential variation in M. haemolytica populations over time and induction of nasopharyngeal colonization and subsequent shedding are 2 areas where knowledge is lacking. In our study, 2 separate loads of 20 mixed-origin, male calves were purchased through an order buyer on different dates. Deep nasopharyngeal cultures (NPC) were performed on all calves on arrival and, if M. haemolytica-negative, a second screening culture was obtained. Calves that were negative on 2 initial NPCs (NEG; n = 4) were subsequently challenged with a previously isolated field strain of M. haemolytica in both the upper and lower respiratory tract, individually housed, and then monitored for M. haemolytica shedding via NPCs at 0.5, 1, 3, 5, 7, and 9 days postchallenge. Naturally M. haemolytica-positive calves (2 per load) were kept for additional daily cultures (POS; n = 4). Individual calf M. haemolytica status for both the POS and NEG groups was inconsistent between study days. Additionally, pulsed-field gel electrophoresis performed on isolates from the positive cultures showed that the NEG calves did not shed the M. haemolytica challenge strain, but rather 2 distinct clusters of M. haemolytica were shared among POS and NEG calves regardless of their initial status. Although sample sizes were small, these findings illustrate how variable the results of a single nasopharyngeal swab can be and the challenges of using an individual culture to truly represent animal M. haemolytica status. PMID:26330399

  3. Fluid diversion and sweep improvement with chemical gels in oil recovery processes. Final report

    SciTech Connect

    Seright, R.S.; Martin, F.D.

    1992-09-01

    The objectives of this project were to identify the mechanisms by which gel treatments divert fluids in reservoirs and to establish where and how gel treatments are best applied. Several different types of gelants were examined, including polymer-based gelants, a monomer-based gelant, and a colloidal-silica gelant. This research was directed at gel applications in water injection wells, in production wells, and in high-pressure gas floods. The work examined how the flow properties of gels and gelling agents are influenced by permeability, lithology, and wettability. Other goals included determining the proper placement of gelants, the stability of in-place gels, and the types of gels required for the various oil recovery processes and for different scales of reservoir heterogeneity. During this three-year project, a number of theoretical analyses were performed to determine where gel treatments are expected to work best and where they are not expected to be effective. The most important, predictions from these analyses are presented. Undoubtedly, some of these predictions will be controversial. However, they do provide a starting point in establishing guidelines for the selection of field candidates for gel treatments. A logical next step is to seek field data that either confirm or contradict these predictions. The experimental work focused on four types of gels: (1) resorcinol-formaldehyde, (2) colloidal silica, (3) Cr{sup 3+}(chloride)-xanthan, and (4) Cr{sup 3+}(acetate)-polyacrylamide. All experiments were performed at 41{degrees}C.

  4. Polarity reversal of inside-out thyroid follicles cultured within collagen gel: reexpression of specific functions.

    PubMed

    Chambard, M; Verrier, B; Gabrion, J; Mauchamp, J

    1984-01-01

    Isolated porcine thyroid cells cultured in suspension in Eagle Minimum Essential Medium supplemented with calf serum (5-20%) reorganize to form vesicles, i.e. closed structures in which all cells have an inverted polarity as compared to that found in follicles: the apical membranes are bathed by the culture medium. Under these conditions, cells neither concentrate iodide nor respond to acute thyrotropin (TSH) stimulation. When embedded in collagen gel, these vesicles undergo polarity reversal to form follicles. We describe here the change in the orientation of cell polarity and the subsequent reappearance of specific thyroid functions. Six hr after embedding, membrane areas in contact with collagen fibers show basal characteristics. At this time, cells begin to concentrate iodide and to respond to acute TSH stimulation (iodide efflux and increased cAMP levels). Most cells form follicles 24 hr after embedding, but 48 hr are required for the transformation of all vesicles into follicles. This occurs without opening of the tight junctions. Iodide organification is detected 24 hr after embedding, when periodic acid-Schiff positive material, identified as thyroglobulin by immunofluorescence, accumulates in the lumen. Iodide concentration and organification, as well as response to TSH stimulation reach maximal levels after 3 days in the collagen matrix. After a 5-day culture in the collagen matrix in the absence of TSH, cell activity can be stimulated by chronic treatment with low hormone concentrations (10-100 microU/ml). As shown with thyroid cells grown in monolayer on permeable substrates (Chambard M., et al., 1983, J. Cell Biol. 96, 1172-1177), iodide uptake and cAMP-mediated TSH responses are expressed when the halogen and the hormone have direct access to the basal membrane. Organification, on the contrary, requires a closed apical compartment. PMID:6098327

  5. Exploring the kinetics of gelation and final architecture of enzymatically cross-linked chitosan/gelatin gels.

    PubMed

    da Silva, Marcelo A; Bode, Franziska; Grillo, Isabelle; Dreiss, Cécile A

    2015-04-13

    Small-angle neutron scattering (SANS) was used to characterize the nanoscale structure of enzymatically cross-linked chitosan/gelatin hydrogels obtained from two protocols: a pure chemical cross-linking process (C), which uses the natural enzyme microbial transglutaminase, and a physical-co-chemical (PC) hybrid process, where covalent cross-linking is combined with the temperature-triggered gelation of gelatin, occurring through the formation of triple-helices. SANS measurements on the final and evolving networks provide a correlation length (ξ), which reflects the average size of expanding clusters. Their growth in PC gels is restricted by the triple-helices (ξ ∼ 10s of Å), while ξ in pure chemical gels increases with cross-linker concentration (∼100s of Å). In addition, the shear elastic modulus in PC gels is higher than in pure C gels. Our results thus demonstrate that gelatin triple helices provide a template to guide the cross-linking process; overall, this work provides important structural insight to improve the design of biopolymer-based gels. PMID:25772227

  6. Calcium pectinate gel beads obtained from callus cultures pectins as promising systems for colon-targeted drug delivery.

    PubMed

    Günter, Elena A; Popeyko, Oxana V

    2016-08-20

    Low methyl-esterified pectins obtained from the cell walls of the campion (SV, SV>300), tansy (TV, TV>300) and duckweed (LM, LM>300) callus cultures and apple pectin (AP, Classic AU 701) were used as the carriers for colon delivery of prednisolone. The pectins with molecular weight more than 300kDa (SV>300, TV>300, LM>300) formed gels which exhibited the higher gel strength. The higher gel strength of these gels appeared to be related to the higher Mw and the lower degree of methylesterification (DE) of these pectins. Release aspects of prednisolone in the simulated gastric (pH 1.25), intestinal (pH 7.0) and colonic (pH 7.0+pectinase) media were investigated. The LM-5%, AP-3% and AP-5% beads destroyed in simulated intestinal medium probably due to the higher DE of the LM and AP pectins. The SV>300-3% and TV>300-3% prednisolone loaded bead systems showed a high stability at pH 1.25 and pH 7.0. Prednisolone release occurred in a larger extent in colonic medium due to the enzymatic erosion of the beads. The SV>300-3% and TV>300-3% particles showed a more controlled release that appeared to be related to the lower DE, rhamnogalacturonan content, rhamnogalacturonan I branching and the higher linearity and Mw of the TV>300 and SV>300 pectins, as well as to the higher gel strength. This in vitro study suggests that calcium pectinate gel beads obtained from callus cultures pectins can be proposed as potential systems for colon-targeted drug delivery. PMID:27178956

  7. Nearly finished genomes produced using gel microdroplet culturing reveal substantial intraspecies genomic diversity within the human microbiome

    PubMed Central

    Fitzsimons, Michael S.; Novotny, Mark; Lo, Chien-Chi; Dichosa, Armand E.K.; Yee-Greenbaum, Joyclyn L.; Snook, Jeremy P.; Gu, Wei; Chertkov, Olga; Davenport, Karen W.; McMurry, Kim; Reitenga, Krista G.; Daughton, Ashlynn R.; He, Jian; Johnson, Shannon L.; Gleasner, Cheryl D.; Wills, Patti L.; Parson-Quintana, Beverly; Chain, Patrick S.; Detter, John C.; Lasken, Roger S.; Han, Cliff S.

    2013-01-01

    The majority of microbial genomic diversity remains unexplored. This is largely due to our inability to culture most microorganisms in isolation, which is a prerequisite for traditional genome sequencing. Single-cell sequencing has allowed researchers to circumvent this limitation. DNA is amplified directly from a single cell using the whole-genome amplification technique of multiple displacement amplification (MDA). However, MDA from a single chromosome copy suffers from amplification bias and a large loss of specificity from even very small amounts of DNA contamination, which makes assembling a genome difficult and completely finishing a genome impossible except in extraordinary circumstances. Gel microdrop cultivation allows culturing of a diverse microbial community and provides hundreds to thousands of genetically identical cells as input for an MDA reaction. We demonstrate the utility of this approach by comparing sequencing results of gel microdroplets and single cells following MDA. Bias is reduced in the MDA reaction and genome sequencing, and assembly is greatly improved when using gel microdroplets. We acquired multiple near-complete genomes for two bacterial species from human oral and stool microbiome samples. A significant amount of genome diversity, including single nucleotide polymorphisms and genome recombination, is discovered. Gel microdroplets offer a powerful and high-throughput technology for assembling whole genomes from complex samples and for probing the pan-genome of naturally occurring populations. PMID:23493677

  8. Calcium-alginate gel bead cross-linked with gelatin as microcarrier for anchorage-dependent cell culture.

    PubMed

    Kwon, Young Jik; Peng, Ching-An

    2002-07-01

    Valuable products obtainedfrom the cultivation of anchorage-dependent mammalian cells require large-scale processes to obtain commercially useful quantities. It is generally accepted that suspension culture is the ideal mode of operation. Because anchorage-dependent cells need surfaces to be able to attach and spread, the incorporation of microcarriers to suspension culture is indispensable. Since the dextran-based microcarrier wasfirst introduced, many different types of microcarriers have been developed and commercialized. In this study, alginate-based microcarriers were made in the following order: (i) calcium-alginate gel beads prepared by dropping a blend of sodium alginate and propylene glycol alginate (PGA) into calcium chloride solution, (ii) the PGA section of gel beads cross-linked with gelatin in alkaline solution (i.e., via the transacylation reaction between the ester group of PGA and amino group of gelatin), and (iii) gelatin membrane around the beads further cross-linked by glutaraldehyde. The glutaraldehyde-treated gelatintransacylated PGA/alginate microcarrier showed superior features in high stability under phosphate-containing solution, density close to that of culture medium, and transparency. Moreover, the Chinese hamster ovary CHO-KI and amphotropic retrovirus producer PA317 cells cultivated on the newly synthesized microcarriers exhibited similar growth kinetics of these two types of cell lines cultured on commercial polystyrene microcarriers. However, cell morphology was easily monitored on the transparent microcarriers made in this study. PMID:12139248

  9. An improved method for western blotting when extracting proteins from mammalian cells cultured on a collagen gel under serum-free conditions.

    PubMed

    Ishihara, Seiichiro; Mizutani, Takeomi; Kawabata, Kazushige; Haga, Hisashi

    2016-01-01

    Western blotting is a widely used method for detection and quantification of specific proteins extracted from mammalian cells. In the conventional method of protein extraction, we found that collagen-containing gels interfered with detection of the p65 protein (one of the subunits in the NF-κB family of proteins) in human lung adenocarcinoma A549 cells cultured on a collagen gel containing serum. In contrast, the collagen gels did not affect detection of the GAPDH protein. Then, we established an improved method for preparation of protein extracts (using trichloroacetic acid fixation and collagenase treatment) from the cells cultured on the collagen gel. Using the improved method, we were able to detect p65 proteins without loss in A549 cells cultured on a collagen gel under serum-free conditions, but we could not detect the proteins if serum was present in cell culture. Thus, using western blotting and serum-free culture conditions, we succeeded in comparing the p65 expression between the cells grown in a plastic dish and cells grown on a collagen gel. PMID:25005915

  10. Inhibition of Fusarium graminearum growth in flour gel cultures by hexane-soluble compounds from oat (Avena sativa L.) flour.

    PubMed

    Doehlert, Douglas C; Rayas-Duarte, Patricia; McMullen, Michael S

    2011-12-01

    Fusarium head blight, incited by the fungus Fusarium graminearum, primarily affects wheat (Triticum aestivum) and barley (Hordeum vulgarum), while oat (Avena sativa) appears to be more resistant. Although this has generally been attributed to the open panicle of oats, we hypothesized that a chemical component of oats might contribute to this resistance. To test this hypothesis, we created culture media made of wheat, barley, and oat flour gels (6 g of flour in 20 ml of water, gelled by autoclaving) and inoculated these with plugs of F. graminearum from actively growing cultures. Fusarium growth was measured from the diameter of the fungal plaque. Plaque diameter was significantly smaller on oat flour cultures than on wheat or barley cultures after 40 to 80 h of growth. Ergosterol concentration was also significantly lower in oat cultures than in wheat cultures after growth. A hexane extract from oats added to wheat flour also inhibited Fusarium growth, and Fusarium grew better on hexane-defatted oat flour. The growth of Fusarium on oat flour was significantly and negatively affected by the oil concentration in the oat, in a linear relationship. A hexane-soluble chemical in oat flour appears to inhibit Fusarium growth and might contribute to oat's resistance to Fusarium head blight. Oxygenated fatty acids, including hydroxy, dihydroxy, and epoxy fatty acids, were identified in the hexane extracts and are likely candidates for causing the inhibition. PMID:22186063

  11. Tissue in Cube: In Vitro 3D Culturing Platform with Hybrid Gel Cubes for Multidirectional Observations.

    PubMed

    Hagiwara, Masaya; Kawahara, Tomohiro; Nobata, Rina

    2016-07-01

    An in vitro 3D culturing platform enabling multidirectional observations of 3D biosamples is presented. The 3D structure of biosamples can be recognized without fluorescence. The cubic platform employs two types of hydrogels that are compatible with conventional culture dishes or well plates, facilitating growth in culture, ease of handling, and viewing at multiple angles. PMID:27128576

  12. Collagen-gel-induced resistance of overlying keratinocyte cultures to photosensitization

    NASA Astrophysics Data System (ADS)

    Katsantonis, John C.; Georgiou, Savas K.; Providaki, Mary G.; Vlahonikolis, John G.; Tosca, Andronicki D.

    1997-12-01

    In the present study it was found that human keratinocytes grown on collagen substrate, exhibited increased resistance to the hematoprophyrin-mediated photodynamic treatment, in comparison to keratinocytes grown on Petri dishes without collagen. Interestingly, no protection was afforded by the collagen gel to the cells in the corresponding control ('hematoprophyrin only' and 'light only') experiments. This observation was found to be independent of light dose and drug concentration, and the relative degree of resistance was the same for both normal and malignant cells. The degree of keratinocyte resistance was found to be closely related to the duration of cell attachment on the collagen substrate. These results are indicative of an active interference of collagen gel with the cellular evolution of the photodynamic phenomenon and they are also suggestive of variation in the photodynamic treatment efficacy according to the cellular environment.

  13. Cultural noise in EM prospecting for geothermal resources. Final report

    SciTech Connect

    Merewether, D.E.; Cox, R.W.; Pate, R.C.

    1981-02-05

    Numerical analysis tools are used to characterize the fields reradiated by cultural scatterers like powerlines, pipelines and fences. These fields are then compared to the returns expected from deeply buried targets and suggestions are made for methods to identify and remove cultural noise from survey data.

  14. Native gel analysis of macromolecular protein complexes in cultured mammalian cells.

    PubMed

    Munawar, Nayla; Olivero, Giorgio; Jerman, Emilia; Doyle, Benjamin; Streubel, Gundula; Wynne, Kieran; Bracken, Adrian; Cagney, Gerard

    2015-11-01

    Native gel electrophoresis enables separation of cellular proteins in their non-denatured state. In experiments aimed at analysing proteins in higher order or multimeric assemblies (i.e. protein complexes) it offers some advantages over rival approaches, particularly as an interface technology with mass spectrometry. Here we separated fractions from HEK293 cells by native electrophoresis in order to survey protein complexes in the cytoplasmic, nuclear and chromatin environments, finding 689 proteins distributed among 217 previously described complexes. As expected, different fractions contained distinct combinations of macromolecular complexes, with subunits of the same complex tending to co-migrate. Exceptions to this observation could often be explained by the presence of subunits shared among different complexes. We investigated one identified complex, the Polycomb Repressor Complex 2 (PRC2), in more detail following affinity purification of the EZH2 subunit. This approach resulted in the identification of all previously reported members of PRC2. Overall, this work demonstrates that the use of native gel electrophoresis as an upstream separating step is an effective approach for analysis of the components and cellular distribution of protein complexes. PMID:26223664

  15. Analysis of soybean tissue culture protein dynamics using difference gel electrophoresis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excised hypocotyls from developing soybean (Glycine max (L.) merr. cv. Jack) were cultivated on agar-solidified medium until callus formed. The calli were then propagated in liquid medium until stable, relatively uniform, finely-divided suspension cultures were obtained. Cells were typically transfe...

  16. Morphology of capillary-like structures in a three-dimensional aorta/collagen gel culture.

    PubMed

    Akita, M; Murata, E; Merker, H J; Kaneko, K

    1997-04-01

    The morphology of capillary-like tubes was investigated by electron microscopy (TEM and SEM) using an in vitro model of capillarogenesis (aorta/collagen type I gel). This model allowed morphological comparisons with in vivo capillaries and an evaluation of the functional maturity of the endothelium to be made. The lumina developing in vitro were demarcated by endothelial cells of varying thickness (0.1-2 microns). Pericytes were resting on the outside. The endothelial cells were characterized by contacts of varying length with tight and gap junctions and occasional indentations. The inner surface exhibited areas both with pronounced and without any endocytotic activity. In addition to a large Golgi apparatus, a varying number of cell organelles occurred depending on the thickness of the endothelium. Bundles consisting of microfilaments were often located underneath the outer cell membrane and in the vicinity of contact areas. A lamina densa was in the process of formation. The capillaries grown in vitro closely resembled those in vivo and showed a high degree of differentiation. Hence, this in vitro model allows the study of a number of functions of endothelial cells. PMID:9134083

  17. 76 FR 34773 - Final Safety Culture Policy Statement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-14

    ... Power Plant Operations'' (54 FR 3424; January 24, 1989), applies to all individuals engaged in... of Employees in the Nuclear Industry to Raise Safety Concerns Without Fear of Retaliation'' (61 FR..., Federal Register notice (FRN) (74 FR 6433) entitled ``Safety Culture Policy Statement Development:...

  18. The osteogenic properties of multipotent mesenchymal stromal cells in cultures on TiO₂ sol-gel-derived biomaterial.

    PubMed

    Marycz, Krzysztof; Śmieszek, Agnieszka; Grzesiak, Jakub; Siudzińska, Anna; Marędziak, Monika; Donesz-Sikorska, Anna; Krzak, Justyna

    2015-01-01

    The biocompatibility of the bone implants is a crucial factor determining the successful tissue regeneration. The aim of this work was to compare cellular behavior and osteogenic properties of rat adipose-derived multipotent stromal cells (ASCs) and bone marrow multipotent stromal cells (BMSCs) cultured on metallic substrate covered with TiO2 sol-gel-derived nanolayer. The morphology, proliferation rate, and osteogenic differentiation potential of both ASCs and BMSCs propagated on the biomaterials were examined. The potential for osteogenic differentiation of ASCs and BMSCs was determined based on the presence of specific markers of osteogenesis, that is, alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCL). Additionally, the concentration of calcium and phosphorus in extracellular matrix was determined using energy-dispersive X-ray spectroscopy (SEM-EDX). Obtained results showed that TiO2 layer influenced proliferation activity of ASCs, which manifested by shortening of population doubling time and increase of OPN secretion. However, characteristic features of cells morphology and growth pattern of cultures prompted us to conclude that ultrathin TiO2 layer might also enhance osteodifferentiation of BMSCs. Therefore in our opinion, both populations of MSCs should be used for biological evaluation of biomaterials compatibility, such results may enhance the area of investigations related to regenerative medicine. PMID:25710015

  19. The Osteogenic Properties of Multipotent Mesenchymal Stromal Cells in Cultures on TiO2 Sol-Gel-Derived Biomaterial

    PubMed Central

    Marycz, Krzysztof; Śmieszek, Agnieszka; Grzesiak, Jakub; Siudzińska, Anna; Marędziak, Monika; Donesz-Sikorska, Anna; Krzak, Justyna

    2015-01-01

    The biocompatibility of the bone implants is a crucial factor determining the successful tissue regeneration. The aim of this work was to compare cellular behavior and osteogenic properties of rat adipose-derived multipotent stromal cells (ASCs) and bone marrow multipotent stromal cells (BMSCs) cultured on metallic substrate covered with TiO2 sol-gel-derived nanolayer. The morphology, proliferation rate, and osteogenic differentiation potential of both ASCs and BMSCs propagated on the biomaterials were examined. The potential for osteogenic differentiation of ASCs and BMSCs was determined based on the presence of specific markers of osteogenesis, that is, alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCL). Additionally, the concentration of calcium and phosphorus in extracellular matrix was determined using energy-dispersive X-ray spectroscopy (SEM-EDX). Obtained results showed that TiO2 layer influenced proliferation activity of ASCs, which manifested by shortening of population doubling time and increase of OPN secretion. However, characteristic features of cells morphology and growth pattern of cultures prompted us to conclude that ultrathin TiO2 layer might also enhance osteodifferentiation of BMSCs. Therefore in our opinion, both populations of MSCs should be used for biological evaluation of biomaterials compatibility, such results may enhance the area of investigations related to regenerative medicine. PMID:25710015

  20. Smad signal pathway regulates angiogenesis via endothelial cell in an adipose-derived stromal cell/endothelial cell co-culture, 3D gel model.

    PubMed

    Lin, Shiyu; Xie, Jing; Gong, Tao; Shi, Sirong; Zhang, Tao; Fu, Na; Lin, Yunfeng

    2016-01-01

    Co-implantation of adipose-derived stromal cells (ASCs) and endothelial cells (ECs) can markedly expedite the formation of functional microvascular beds and provides possible methods for cell-based revascularization therapies to treat various diseases. Furthermore, we investigated the role of TGFβ/Smad signaling pathway for angiogenesis in a three-dimensional (3D) collagen gel model established in vitro with co-culture between ASCs and ECs. We found that angiogenesis was attenuated in the co-culture gels after inhibition of ALK5/Smad2/3 with SB431542. Genes coding for VEGF-A, VEGF-B, VE-ca, FGF-1, PDGF, BMP-4, and BMP-7 were significantly reduced in both mono-cultured and co-cultured ECs. Furthermore, the decrease in co-cultured ECs was prominent relative to mono-cultured ECs. Taken together, these findings suggest that in the co-culture between ASCs and ECs, TGFβ/Smad signal pathway regulates angiogenesis via ECs; moreover, the findings that the co-cultured ECs were regulated more significantly than mono-cultured ECs suggest that suppression of Smad signal pathway may regulate the paracrine secretion of ASCs to further modulate angiogenesis of ECs. PMID:26694166

  1. A study of the kinetics of swelling in cylindrical polystyrene gels: Mechanical behavior and final properties after swelling

    NASA Astrophysics Data System (ADS)

    Hakiki, Abdelkrim; Herz, Jean E.

    1994-11-01

    Mechanical properties of cylindrical polystyrene gels were investigated both by the kinetics of swelling and uniaxial elastic modulus. These gels were prepared by specific chemical reactions using well-defined difunctional and precursor polymers. From the data of the kinetics of swelling we determined the cooperative diffusion coefficient of the gel and the related mesh size. Experimental results were found to be consistent with the theory of Tanaka et al. Elastic moduli were interpreted on the basis of the phantom and affine models.

  2. Increase of the final setting time of brushite cements by using chondroitin 4-sulfate and silica gel.

    PubMed

    Tamimi-Mariño, F; Mastio, J; Rueda, C; Blanco, L; López-Cabarcos, E

    2007-06-01

    Chondroitin 4-sulfate (C4S) is a bioactive glycosaminoglycan with inductive properties in bone and tissue regeneration. Dicalcium phosphate dehydrate cements (known as brushite) are biocompatible and resorbable materials used in bone and dental surgery. In this study we analyzed the effect of C4S on the setting of a calcium phosphate cement and the properties of the resulting material. Brushite based cement powder was synthesised by mixing monocalcium phosphate with beta-tricalcium phosphate and sodium pyrophosphate. When the concentration of C4S, in the liquid added to the cement powder, was between 1 and 8% the cement final setting time increases. Furthermore, the cement diametral tensile strength remains unaffected when solutions with concentrations of C4S below 5% were used, but decreases at higher C4S concentrations. Calorimetric analysis showed that the cements prepared with C4S alone and in combination with silica gel have a greater content of hydrated water. We concluded from our study that the addition of small amounts of C4S increases the cement setting time without affecting its diametral tensile strength and at the same time improves the cement's hydrophilicity. PMID:17277974

  3. Facing Finality: Cognitive and Cultural Studies on Death and Dying "Arabic Culture"

    ERIC Educational Resources Information Center

    Al-Meshhedany, Amna A. Hasan; Al-Sammerai, Nabiha S. Mehdi

    2010-01-01

    Semantics is a study of human beings cultural background, has from its beginning as a field of study been concerned with the study of humans understanding of culture. Understanding the meaning of "death" has been of great importance to many of the central theoretical developments in this field, especially as it imposes on studies of…

  4. Defined media for plant tissue culture: Final report

    SciTech Connect

    Good, N.E.

    1986-01-01

    This grant was for the purpose of developing improved plant tissue culture media. The rationale was to introduce the use of low pKa hydrogen ion buffers to stabilize pH and to introduce the use of slow release forms of the plant hormones, auxin and cytokinin, to provide the tissues with a constant supply of these essential factors. The zwittionic buffer, MES, proved useful for pH stabilization, while a wide range of indoleacetylamino acids provided a wide range of levels of available amino acids with consequent different levels of development of shoots, roots or callus. In general, some free indoleacetic acid in addition to the conjugate seemed necessary for organogenesis, but this phenomenon depended very much on the level of cytokinin. Time did not permit us to make any significant progress in the development of slow-release forms of cytokinins. 2 figs.

  5. Algae culture for cattle feed and water purification. Final report

    SciTech Connect

    Varani, F.T.; Schellenbach, S.; Veatch, M.; Grover, P.; Benemann, J.

    1980-05-16

    The feasibility of algae growth on centrate from anaerobic digester effluent and the refeed of both effluent solids and the algae to feedlot cattle were investigated. The digester was operated with dirt feedlot manure. The study serves as a supplement for the work to design a utility sized digester for the City of Lamar to convert local feedlot manure into a fuel gas. The biogas produced would power the electrical generation plant already in service. Previous studies have established techniques of digester operation and the nutritional value for effluent solids as fed to cattle. The inclusion of a single-strain of algae, Chlorella pyrenidosa in the process was evaluated here for its capability (1) to be grown in both open and closed ponds of the discharge water from the solids separation part of the process, (2) to purify the discharge water, and (3) to act as a growth stimulant for cattle feed consumption and conversion when fed at a rate of 6 grams per head per day. Although it was found that the algae could be cultured and grown on the discharge water in the laboratory, the study was unable to show that algae could accomplish the other objectives successfully. However, the study yielded supplementary information useful to the overall process design of the utility plant. This was (1) measurement of undried digester solids fed to cattle in a silage finishing ration (without algae) at an economic value of $74.99 per dry ton based on nutritional qualities, (2) development of a centrate treatment system to decolorize and disinfect centrate to allow optimum algae growth, and (3) information on ionic and mass balances for the digestion system. It is the recommendation of this study that algae not be used in the process in the Lamar bioconversion plant.

  6. Final Technical Report for 'Investigations of the Role of Protozoa in Transformations of Marine Biopolymers using Phaeocytis Polymer Gels as a Model'

    SciTech Connect

    Lessard, Evelyn

    2003-04-01

    protists are able to use the polymer for nutrition and growth. This is the first demonstration of the ingestion and utilization of a natural marine biopolymer by protists. We also isolated three bacterial strains from our Phaeocystis cultures. All three bacterial strains were capable of growing solely on the polymer gels produced by Phaeocystis without added inorganic nitrogen sources. We used the bacterial and protist strains to investigate degradation and alterations (size, chemical composition) of Phaeocystis polymer gels by bacteria alone and in the presence of protists. In a typical experiment, bacterial abundance in the presence of protists was reduced to one third of that in the control due to grazing, but the degradation rate was about the same. This indicates either that grazing by the protist somehow enhanced the per cell rate of bacterial degradation and/or the protist was ingesting polymer directly. Residual polymer remained after weeks, but the mean the mean diameter of the polymers were shortened considerably to ca. 200 nm. These results, along with other lines of evidence, suggest that it may be the length of polymer that limits degradation, which has important implications for the large pool of refractory DOM in the oceans. Chemical analyses indicated that the polymers are carbohydrate-rich and that the nitrogen is not proteinaceous, but most likely in the form of low molecular weight compounds such as amino sugars or sialic acid, and that they had a surprisingly low C:N ratios (<9). Extracellular polymers may therefore provide a nutritional substrate for bacteria and protists without the need for other sources of nitrogen in nature.

  7. Levodopa-Carbidopa Intestinal Gel in Advanced Parkinson'd Disease: Final 12-Month, Open-Label Results

    PubMed Central

    Fernandez, Hubert H; Standaert, David G; Hauser, Robert A; Lang, Anthony E; Fung, Victor SC; Klostermann, Fabian; Lew, Mark F; Odin, Per; Steiger, Malcolm; Yakupov, Eduard Z; Chouinard, Sylvain; Suchowersky, Oksana; Dubow, Jordan; Hall, Coleen M; Chatamra, Krai; Robieson, Weining Z; Benesh, Janet A; Espay, Alberto J

    2015-01-01

    Motor complications in Parkinson's disease (PD) are associated with long-term oral levodopa treatment and linked to pulsatile dopaminergic stimulation. l-dopa-carbidopa intestinal gel (LCIG) is delivered continuously by percutaneous endoscopic gastrojejunostomy tube (PEG-J), which reduces l-dopa-plasma–level fluctuations and can translate to reduced motor complications. We present final results of the largest international, prospective, 54-week, open-label LCIG study. PD patients with severe motor fluctuations (>3 h/day “off” time) despite optimized therapy received LCIG monotherapy. Additional PD medications were allowed >28 days post-LCIG initiation. Safety was the primary endpoint measured through adverse events (AEs), device complications, and number of completers. Secondary endpoints included diary-assessed off time, “on” time with/without troublesome dyskinesia, UPDRS, and health-related quality-of-life (HRQoL) outcomes. Of 354 enrolled patients, 324 (91.5%) received PEG-J and 272 (76.8%) completed the study. Most AEs were mild/moderate and transient; complication of device insertion (34.9%) was the most common. Twenty-seven (7.6%) patients withdrew because of AEs. Serious AEs occurred in 105 (32.4%), most commonly complication of device insertion (6.5%). Mean daily off time decreased by 4.4 h/65.6% (P < 0.001). On time without troublesome dyskinesia increased by 4.8 h/62.9% (P < 0.001); on time with troublesome dyskinesia decreased by 0.4 h/22.5% (P = 0.023). Improvements persisted from week 4 through study completion. UPDRS and HRQoL outcomes were also improved throughout. In the advanced PD population, LCIG's safety profile consisted primarily of AEs associated with the device/procedure, l-dopa/carbidopa, and advanced PD. LCIG was generally well tolerated and demonstrated clinically significant improvements in motor function, daily activities, and HRQoL sustained over 54 weeks. © 2014 The Authors. Movement Disorders published by Wiley

  8. The influence of particle size and static magnetic fields on the uptake of magnetic nanoparticles into three dimensional cell-seeded collagen gel cultures.

    PubMed

    Lewis, Emily E L; Child, Hannah W; Hursthouse, Andrew; Stirling, David; McCully, Mark; Paterson, David; Mullin, Margaret; Berry, Catherine C

    2015-08-01

    Over recent decades there has been and continues to be major advances in the imaging, diagnosis and potential treatment of medical conditions, by the use of magnetic nanoparticles. However, to date the majority of cell delivery studies employ a traditional 2D monolayer culture. This article aims to determine the ability of various sized magnetic nanoparticles to penetrate and travel through a cell seeded collagen gel model, in the presence or absence of a magnetic field. Three different sized (100, 200, and 500 nm) nanoparticles were employed in the study. The results showed cell viability was unaffected by the presence of nanoparticles over a 24-h test period. The initial uptake of the 100 nm nanoparticle into the collagen gel structure was superior compared to the larger sized nanoparticles under the influence of a magnetic field and incubated for 24 h. Interestingly, it was the 200 nm nanoparticles, which proved to penetrate the gel furthest, under the influence of a magnetic field, during the initial culture stage after 1-h incubation. PMID:25358626

  9. Bio-printing of collagen and VEGF-releasing fibrin gel scaffolds for neural stem cell culture.

    PubMed

    Lee, Yeong-Bae; Polio, Samuel; Lee, Wonhye; Dai, Guohao; Menon, Lata; Carroll, Rona S; Yoo, Seung-Schik

    2010-06-01

    Time-released delivery of soluble growth factors (GFs) in engineered hydrogel tissue constructs promotes the migration and proliferation of embedded cells, which is an important factor for designing scaffolds that ultimately aim for neural tissue regeneration. We report a tissue engineering technique to print murine neural stem cells (C17.2), collagen hydrogel, and GF (vascular endothelial growth factor: VEGF)-releasing fibrin gel to construct an artificial neural tissue. We examined the morphological changes of the printed C17.2 cells embedded in the collagen and its migration toward the fibrin gel. The cells showed high viability (92.89+/-2.32%) after printing, which was equivalent to that of manually-plated cells. C17.2 cells printed within 1mm from the border of VEGF-releasing fibrin gel showed GF-induced changes in their morphology. The cells printed in this range also migrated toward the fibrin gel, with the total migration distance of 102.4+/-76.1microm over 3days. The cells in the control samples (fibrin without the VEGF or VEGF printed directly in collagen) neither proliferated nor migrated. The results demonstrated that bio-printing of VEGF-containing fibrin gel supported sustained release of the GF in the collagen scaffold. The presented method can be gainfully used in the development of three-dimensional (3D) artificial tissue assays and neural tissue regeneration applications. PMID:20211178

  10. Diamond turned master molds for bulk casting of sol-gel silica diffractive optical elements. Final report

    SciTech Connect

    Maxey, L.C.; Nogues, J.L.; Moreshead, B.

    1997-08-01

    This CRADA has combined the resources of a national laboratory and an innovative small company to investigate the production of diffractive lenses in silica glass, using diamond turned master molds. The method for producing these lenses combines the unique characteristics of the sol-gel silica replication process, pioneered by Geltech, with the state-of-the-art diamond turning expertise of the Oak Ridge Centers for Manufacturing Technology (ORCMT). A conventional lens focuses light by using a curved surface to refract (or bend) the incoming light so that it will form an image. These lenses are usually thick glass elements with one or both surfaces shaped into convex or concave spherical shapes. Traditionally, these lenses are produced by grinding and polishing the glass to the desired shape. Light can also be focused using the phenomenon of diffraction, rather than refraction. A lens of this type uses precision microscopic surface features to bend the light so that it forms an image. The result is a lens that is thinner and lighter than its refractive counterpart. Production of diffractive lenses requires the ability to accurately produce the precision microscopic features necessary to achieve controlled diffraction. Diffractive lenses have, for the most part, been limited to infra-red applications because the manufacturing technologies available have not enabled their use at visible wavelengths. Except in limited applications, these lenses have remained laboratory curiosities, because they must be individually produced by diamond turning infra-red optical materials. Geltech`s sol-gel silica replication process offers the opportunity to mass produce diffractive lenses in high quality silica glass. These lenses can be produced by diamond turning the necessary precision microscopic surface features into master surfaces that are replicated into intermediate molds. These molds are then used to produce a batch of diffractive lenses using the sol-gel process.

  11. Denaturing gradient gel electrophoresis as a tool to determine batch similarity of probiotic cultures of porcine cecal bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A reconstituted porcine-derived continuous-flow (RPCF) culture of gastrointestinal bacteria effective against enterotoxigenic Escherichia coli in weanling pigs has been maintained for several years and used as a parent culture from which to derive additional RPCF cultures. The integrity and health ...

  12. Studies on gel electrolyte based on nitrile-butadiene copolymers. Final report, 1 November 1991-30 November 1992

    SciTech Connect

    Sircar, A.K.; Kumar, B.; Linden, S.M.; Weissman, P.T.

    1993-06-01

    This study is concerned with the preparation of a hybrid electrolyte, suitable for solid-polymer batteries. Based on the study of ionic conductivity in the presence of LiBF4 of a number of nitrile-butadiene copolymers (NBR), hydrogenated NBR (HNBR) was selected as the host polymer. DC conductivity studies with three different lithium salts in different plasticizers showed the highest conductivity for LiBF4. Conductivity of LiBF4 in different plasticizers decreases in the order DMF > DMAC > Gamma butyrolactone > NMP > PC=gamma-valerolactone > glymes. NMP was chosen as the plasticizer for hybrid films based on its moderate conductivity, low vapor pressure, and low freezing point. Polymer electrolytes, Gel electrolytes, Ionic conductivity.

  13. 3D Tissue Culturing: Tissue in Cube: In Vitro 3D Culturing Platform with Hybrid Gel Cubes for Multidirectional Observations (Adv. Healthcare Mater. 13/2016).

    PubMed

    Hagiwara, Masaya; Kawahara, Tomohiro; Nobata, Rina

    2016-07-01

    An in vitro 3D culturing platform enabling multidirectional observations of 3D biosamples is presented by M. Hagiwara and co-workers on page 1566. 3D recognition of a sample structure can be achieved by facilitating multi-directional views using a standard microscope without a laser system. The cubic platform has the potential to promote 3D culture studies, offering easy handling and compatibility with commercial culture plates at a low price tag. PMID:27384934

  14. High efficiency TiO2 photocatalysts by the sol-gel process. Final report, 1 April-30 September 1995

    SciTech Connect

    Huang, Y.; Chu, C.J.

    1995-10-25

    Objective of Phase I project is to demonstrate that the dye-sensitized and doped materials by sol-gel process can be used in the photocatalytic reaction for oxidation of chemical wastes under the simulated solar irradiation, and to develop innovative technologies to improve the efficiency of photodegradation of chemical waste. In Phase I research, the authors met the following goals: (1) Development of various technologies on fabrication of TiO2 materials including powders, and porous aerogels with much higher specific surface area comparing to commercial TiO2 anatase powder-Degussa P25 powder. (2) Characterization of crystallographic phase development, morphologies and surface area of materials using XRD, SEM and BET analyser. (3) Investigation on effects of various parameters, such as tungsten doping, dye-sensitization crystallographic phase, morphologies and specific surface area, on efficiency of photodegradation of chemical waste under the simulated solar radiation. (4) Improvements of photocatalytic efficiency by developing innovative technologies, such as using aerosol and aerogel routes with doping and sensitized dye.

  15. Efficacy and Safety of a Low Molecular Weight Hyaluronic Acid Topical Gel in the Treatment of Facial Seborrheic Dermatitis Final Report

    PubMed Central

    Rowland Powell, Callie

    2014-01-01

    Objective: Hyaluronic acid sodium salt gel 0.2% is a topical device effective in reducing skin inflammation. Facial seborrheic dermatitis, characterized by erythema and or flaking/scaling in areas of high sebaceous activity, affects up to five percent of the United States population. Despite ongoing study, the cause of the condition is yet unknown, but has been associated with yeast colonization and resultant immune derived inflammation. First-line management typically is with keratolytics, topical steroids, and topical antifungals as well as the targeted immunosuppressant agents pimecrolimus and tacrolimus. The objective of this study was to evaluate the efficacy and safety of a novel topical antiinflammatory containing low molecular weight hyaluronic acid. Design and setting: Prospective, observational, non-blinded safety and efficacy study in an outpatient setting. Participants: Individuals 18 to 75 years of age with facial seborrheic dermatitis. Measurements: Outcome measures included scale, erythema, pruritus, and the provider global assessment, all measured on a five-point scale. Subjects were assessed at baseline, Week 2, Week 4, and Week 8. Results: Final data with 13 of 17 subjects are presented. Hyaluronic acid sodium salt gel 0.2% was shown through visual grading assessments to improve the provider global assessment by 65.48 percent from baseline to Week 4. Reductions in scale, erythema, and pruritus were 76.9, 64.3, and 50 percent, respectively, at Week 4. At Week 8, the provider global assessment was improved from baseline in 92.3 percent of subjects. Conclusion: Treatment with topical low molecular weight hyaluronic acid resulted in improvement in the measured endpoints. Final data reveal continued improvement from that seen in the interim data shown previously. Topical low molecular weight hyaluronic acid is another option that may be considered for the treatment of facial seborrheic dermatitis in the adult population. Compliance and tolerance were

  16. Modeling chemoresponsive polymer gels.

    PubMed

    Kuksenok, Olga; Deb, Debabrata; Dayal, Pratyush; Balazs, Anna C

    2014-01-01

    Stimuli-responsive gels are vital components in the next generation of smart devices, which can sense and dynamically respond to changes in the local environment and thereby exhibit more autonomous functionality. We describe recently developed computational methods for simulating the properties of such stimuli-responsive gels in the presence of optical, chemical, and thermal gradients. Using these models, we determine how to harness light to drive shape changes and directed motion in spirobenzopyran-containing gels. Focusing on oscillating gels undergoing the Belousov-Zhabotinksy reaction, we demonstrate that these materials can spontaneously form self-rotating assemblies, or pinwheels. Finally, we model temperature-sensitive gels that encompass chemically reactive filaments to optimize the performance of this system as a homeostatic device for regulating temperature. These studies could facilitate the development of soft robots that autonomously interconvert chemical and mechanical energy and thus perform vital functions without the continuous need of external power sources. PMID:24498954

  17. The CDCC's Project No. 7: "The Education and Cultural Development of Migrants." Final Report of the Project Group.

    ERIC Educational Resources Information Center

    Council for Cultural Cooperation, Strasbourg (France).

    The final report of a project group representing the 18 member countries of the Council of Europe Council for Cultural Co-operation investigates education and cultural development of migrants. The report discusses methodology and reasons for selecting an intercultural approach to migrant education in terms of interculturalism's basic elements:…

  18. Association of diverse bacterial communities in human bile samples with biliary tract disorders: a survey using culture and polymerase chain reaction-denaturing gradient gel electrophoresis methods.

    PubMed

    Tajeddin, E; Sherafat, S J; Majidi, M R S; Alebouyeh, M; Alizadeh, A H M; Zali, M R

    2016-08-01

    Bacterial infection is considered a predisposing factor for disorders of the biliary tract. This study aimed to determine the diversity of bacterial communities in bile samples and their involvement in the occurrence of biliary tract diseases. A total of 102 bile samples were collected during endoscopic retrograde cholangiopancreatography (ERCP). Characterization of bacteria was done using culture and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) methods. Antimicrobial susceptibility of the isolates was determined based on the Clinical and Laboratory Standards Institute (CLSI) guidelines and identity of the nucleotide sequences of differentiated bands from the DGGE gels was determined based on GenBank data. In total, 41.2 % (42/102) of the patients showed bacterial infection in their bile samples. This infection was detected in 21 % (4/19), 45.4 % (5/11), 53.5 % (15/28), and 54.5 % (24/44) of patients with common bile duct stone, microlithiasis, malignancy, and gallbladder stone, respectively. Escherichia coli showed a significant association with gallstones. Polymicrobial infection was detected in 48 % of the patients. While results of the culture method established coexistence of biofilm-forming bacteria (Pseudomonas aeruginosa, E. coli, Klebsiella pneumoniae, Enterococcus spp., and Acinetobacter spp.) in different combinations, the presence of Capnocytophaga spp., Lactococcus spp., Bacillus spp., Staphylococcus haemolyticus, Enterobacter or Citrobacter spp., Morganella spp., Salmonella spp., and Helicobacter pylori was also characterized in these samples by the PCR-DGGE method. Multidrug resistance phenotypes (87.5 %) and resistance to third- and fourth-generation cephalosporins and quinolones were common in these strains, which could evolve through their selection by bile components. Ability for biofilm formation seems to be a need for polymicrobial infection in this organ. PMID:27193890

  19. Initiatives to improve feedback culture in the final year of a veterinary program.

    PubMed

    Warman, Sheena M; Laws, Emma J; Crowther, Emma; Baillie, Sarah

    2014-01-01

    Despite the recognized importance of feedback in education, student satisfaction with the feedback process in medical and veterinary programs is often disappointing. We undertook various initiatives to try to improve the feedback culture in the final clinical year of the veterinary program at the University of Bristol, focusing on formative verbal feedback. The initiatives included E-mailed guidelines to staff and students, a faculty development workshop, and a reflective portfolio task for students. Following these initiatives, staff and students were surveyed regarding their perceptions of formative feedback in clinical rotations, and focus groups were held to further explore issues. The amount of feedback appeared to have increased, along with improved recognition of feedback by students and increased staff confidence and competence in the process. Other themes that emerged included inconsistencies in feedback among staff and between rotations; difficulties with giving verbal feedback to students, particularly when it relates to professionalism; the consequences of feedback for both staff and students; changes and challenges in students' feedback-seeking behavior; and the difficulties in providing accurate, personal end-of-rotation assessments. This project has helped improve the feedback culture within our clinics; the importance of sustaining and further developing the feedback culture is discussed in this article. PMID:24686719

  20. CONFORMANCE IMPROVEMENT USING GELS

    SciTech Connect

    Randall S. Seright

    2004-09-30

    This report describes work performed during the third and final year of the project, ''Conformance Improvement Using Gels.'' Corefloods revealed throughput dependencies of permeability reduction by polymers and gels that were much more prolonged during oil flow than water flow. This behavior was explained using simple mobility ratio arguments. A model was developed that quantitatively fits the results and predicts ''clean up'' times for oil productivity when production wells are returned to service after application of a polymer or gel treatment. X-ray computed microtomography studies of gels in strongly water-wet Berea sandstone and strongly oil-wet porous polyethylene suggested that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than gel-ripping or gel-displacement mechanisms. In contrast, analysis of data from the University of Kansas suggests that the gel-ripping or displacement mechanisms are more important in more permeable, strongly water-wet sandpacks. These findings help to explain why aqueous gels can reduce permeability to water more than to oil under different conditions. Since cement is the most commonly used material for water shutoff, we considered when gels are preferred over cements. Our analysis and experimental results indicated that cement cannot be expected to completely fill (top to bottom) a vertical fracture of any width, except near the wellbore. For vertical fractures with apertures less than 4 mm, the cement slurry will simply not penetrate very far into the fracture. For vertical fractures with apertures greater than 4 mm, the slurry may penetrate a substantial distance into the bottom part of the fracture. However, except near the wellbore, the upper part of the fracture will remain open due to gravity segregation. We compared various approaches to plugging fractures using gels, including (1) varying polymer content, (2) varying placement (extrusion) rate, (3) using partially formed gels, (4

  1. [Project Upper Cumberland. Final Report. Project Upper Cumberland Cultural Arts Program. Final Evaluation. Demonstration Program in Guidance and Counseling. An Evaluation.

    ERIC Educational Resources Information Center

    Flanders, John N.; And Others

    Project Upper Cumberland was a three year endeavor which served 16 Tennessee counties. The final report and evaluation, in three documents, summarizes the three innovative programs which it engendered: (1) teacher inservice training, emphasizing human relations; (2) a pilot cultural arts program (art, music, drama) for grades 1-12; and (3) a pilot…

  2. Platelet-Rich Gel Supernatants Stimulate the Release of Anti-Inflammatory Proteins on Culture Media of Normal Equine Synovial Membrane Explants.

    PubMed

    Ríos, Diana L; López, Catalina; Carmona, Jorge U

    2015-01-01

    The aims were as follows: (1) to evaluate the effects at 48 and 96 h of two concentrations (25 and 50%) of leukocyte and platelet-rich gel (L-PRG) and pure PRG (P-PRG) supernatants on the production/degradation in normal equine synovial membrane explants (SME) of platelet derived growth factor isoform BB, transforming growth factor beta-1, tumor necrosis factor alpha, interleukin (IL-) 4 (IL-4), IL-1 receptor antagonist (IL-1ra), and hyaluronan (HA) synthesis and (2) to correlate these molecules with their respective PRG supernatant treatments. SME from 6 horses were cultured for 96 h with L-PRG and P-PRG supernatants at 25 and 50% concentrations, respectively. SME culture media were changed each 48 h and used for determination by ELISA of the molecules, which were also determined in synovial fluid. 25% L-PRG supernatant produced a sustained release over time of IL-1ra and a gradual release of HA, whereas 50% L-PRG supernatant produced a sustained increase over time of IL-4 and HA. 50% P-PRG supernatant produced an increased and sustained production of IL-1ra and IL-4. The cellular composition and the articular concentration (volume) of a platelet-rich plasma preparation could affect the anti-inflammatory and anabolic joint responses in horses with osteoarthritis. PMID:26090267

  3. Platelet-Rich Gel Supernatants Stimulate the Release of Anti-Inflammatory Proteins on Culture Media of Normal Equine Synovial Membrane Explants

    PubMed Central

    Ríos, Diana L.; López, Catalina; Carmona, Jorge U.

    2015-01-01

    The aims were as follows: (1) to evaluate the effects at 48 and 96 h of two concentrations (25 and 50%) of leukocyte and platelet-rich gel (L-PRG) and pure PRG (P-PRG) supernatants on the production/degradation in normal equine synovial membrane explants (SME) of platelet derived growth factor isoform BB, transforming growth factor beta-1, tumor necrosis factor alpha, interleukin (IL-) 4 (IL-4), IL-1 receptor antagonist (IL-1ra), and hyaluronan (HA) synthesis and (2) to correlate these molecules with their respective PRG supernatant treatments. SME from 6 horses were cultured for 96 h with L-PRG and P-PRG supernatants at 25 and 50% concentrations, respectively. SME culture media were changed each 48 h and used for determination by ELISA of the molecules, which were also determined in synovial fluid. 25% L-PRG supernatant produced a sustained release over time of IL-1ra and a gradual release of HA, whereas 50% L-PRG supernatant produced a sustained increase over time of IL-4 and HA. 50% P-PRG supernatant produced an increased and sustained production of IL-1ra and IL-4. The cellular composition and the articular concentration (volume) of a platelet-rich plasma preparation could affect the anti-inflammatory and anabolic joint responses in horses with osteoarthritis. PMID:26090267

  4. Tetracaine oral gel in patients treated with radiotherapy for head-and-neck cancer: Final results of a phase II study

    SciTech Connect

    Alterio, Daniela . E-mail: daniela.alterio@ieo.it; Jereczek-Fossa, Barbara Alicja; Zuccotti, Gabriele Fulvio Phar; Leon, Maria Elena; Omodeo Sale, Emanuela Phar; Pasetti, Marcella; Modena, Tiziana Phar; Perugini, Paola; Mariani, Luigi; Orecchia, Roberto

    2006-02-01

    Purpose: We performed a phase II study to assess feasibility, pain relief, and toxicity of a tetracaine-based oral gel in the treatment of radiotherapy (RT)-induced mucositis. Methods and Materials: Fifty patients treated with RT for head-and-neck cancer with clinical evidence of acute oral mucositis of grade {>=}2 were scheduled to receive the tetracaine gel. A questionnaire evaluating the effect of the gel was given to all subjects. Results: In 38 patients (79.2%), a reduction in oral cavity pain was reported. Thirty-four patients (82.9%) reported no side effect. Seventy-one percent of patients had no difficulties in gel application. Unpleasant taste of the gel and interference with food taste were noticed in 5 (12%) and 16 patients (39%), respectively. Planned RT course was interrupted less frequently in patients who reported benefit from gel application than in patients who did not (p = 0.014). None of the patients who experienced pain relief needed a nasogastric tube, opposite to the patients who did not report any benefit from gel application (p = 0.001). Conclusion: Tetracaine oral gel administration seemed feasible and safe while reducing RT-induced mucositis-related oral pain in a sizeable proportion of treated head-and-neck cancer patients. A trial designed to compare efficacy of this gel vs. standard treatment is warranted.

  5. Photo-crosslinkable hydrogel-based 3D microfluidic culture device.

    PubMed

    Lee, Youlee; Lee, Jong Min; Bae, Pan-Kee; Chung, Il Yup; Chung, Bong Hyun; Chung, Bong Geun

    2015-04-01

    We developed the photo-crosslinkable hydrogel-based 3D microfluidic device to culture neural stem cells (NSCs) and tumors. The photo-crosslinkable gelatin methacrylate (GelMA) polymer was used as a physical barrier in the microfluidic device and collagen type I gel was employed to culture NSCs in a 3D manner. We demonstrated that the pore size was inversely proportional to concentrations of GelMA hydrogels, showing the pore sizes of 5 and 25 w/v% GelMA hydrogels were 34 and 4 μm, respectively. It also revealed that the morphology of pores in 5 w/v% GelMA hydrogels was elliptical shape, whereas we observed circular-shaped pores in 25 w/v% GelMA hydrogels. To culture NSCs and tumors in the 3D microfluidic device, we investigated the molecular diffusion properties across GelMA hydrogels, indicating that 25 w/v% GelMA hydrogels inhibited the molecular diffusion for 6 days in the 3D microfluidic device. In contrast, the chemicals were diffused in 5 w/v% GelMA hydrogels. Finally, we cultured NSCs and tumors in the hydrogel-based 3D microfluidic device, showing that 53-75% NSCs differentiated into neurons, while tumors were cultured in the collagen gels. Therefore, this photo-crosslinkable hydrogel-based 3D microfluidic culture device could be a potentially powerful tool for regenerative tissue engineering applications. PMID:25641332

  6. Gastroenterology-urology devices; classification of tissue culture media for human ex vivo tissue and cell culture processing applications. Final rule.

    PubMed

    2001-05-16

    The Food and Drug Administration (FDA) is classifying tissue culture media for human ex vivo tissue and cell culture processing applications into class II (special controls). The special control that will apply to this device is a guidance document entitled "Class II Special Controls Guidance Document: issue Culture Media for Human Ex Vivo Tissue and Cell Culture Processing Applications; Final Guidance for Industry and FDA Reviewers." The agency is taking this action in response to a petition submitted under the Federal Food, Drug, and Cosmetic Act (the act) as amended by the Medical Device Amendments of 1976, the Safe Medical Devices Act of 1990, and the Food and Drug Administration Modernization Act of 1997. The agency is classifying these devices into class II (special controls) in order to provide a reasonable assurance of the safety and effectiveness of the devices. PMID:11721690

  7. Polyelectrolyte gels

    SciTech Connect

    Segalman, D.J.; Witkowski, W.R.

    1995-06-01

    Polyelectrolyte (PE) gels are swollen polymer/solvent networks that undergo a reversible volume collapse/expansion through various types of stimulation. Applications that could exploit this large deformation and solvent expulsion/absorption characteristics include robotic {open_quotes}fingers{close_quotes} and drug delivery systems. The goals of the research were to first explore the feasibility of using the PE gels as {open_quotes}smart materials{close_quotes} - materials whose response can be controlled by an external stimulus through a feedback mechanism. Then develop a predictive capability to simulate the dynamic behavior of these gels. This involved experimentally characterizing the response of well-characterized gels to an applied electric field and other stimuli to develop an understanding of the underlying mechanisms which cause the volume collapse. Lastly, the numerical analysis tool was used to simulate various potential engineering devices based on PE gels. This report discusses the pursuit of those goals through experimental and computational means.

  8. A novel injectable thermoresponsive and cytocompatible gel of poly(N-isopropylacrylamide) with layered double hydroxides facilitates siRNA delivery into chondrocytes in 3D culture.

    PubMed

    Yang, Hsiao-yin; van Ee, Renz J; Timmer, Klaas; Craenmehr, Eric G M; Huang, Julie H; Öner, F Cumhur; Dhert, Wouter J A; Kragten, Angela H M; Willems, Nicole; Grinwis, Guy C M; Tryfonidou, Marianna A; Papen-Botterhuis, Nicole E; Creemers, Laura B

    2015-09-01

    Hybrid hydrogels composed of poly(N-isopropylacrylamide) (pNIPAAM) and layered double hydroxides (LDHs) are presented in this study as novel injectable and thermoresponsive materials for siRNA delivery, which could specifically target several negative regulators of tissue homeostasis in cartilaginous tissues. Effectiveness of siRNA transfection using pNIPAAM formulated with either MgAl-LDH or MgFe-LDH platelets was investigated using osteoarthritic chondrocytes. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as an endogenous model gene to evaluate the extent of silencing. No significant adverse effects of pNIPAAM/LDH hydrogels on cell viability were noticed. Cellular uptake of fluorescently labeled siRNA was greatly enhanced (>75%) in pNIPAAM/LDH hydrogel constructs compared to alginate, hyaluronan and fibrin gels, and was absent in pNIPAAM hydrogel without LDH platelets. When using siRNA against GAPDH, 82-98% reduction of gene expression was found in both types of pNIPAAM/LDH hydrogel constructs after 6 days of culturing. In the pNIPAAM/MgAl-LDH hybrid hydrogel, 80-95% of GAPDH enzyme activity was reduced in parallel with gene. Our findings show that the combination of a cytocompatible hydrogel and therapeutic RNA oligonucleotides is feasible. Thus it might hold promise in treating degeneration of cartilaginous tissues by providing supporting scaffolds for cells and interference with locally produced degenerative factors. PMID:26022968

  9. Antibacterial activity of chlorhexidine after final irrigation with ethanol: CLSM and culture-based method analysis.

    PubMed

    Suman, Juliana Martins; Kuga, Milton Carlos; Da Rosa, Ricardo Abreu; Santini, Manuela Favarin; Grazziotin-Soares, Renata; Montagner, Francisco; Só, Marcus ViníCius Reis

    2015-08-01

    This study investigated the effect of 95% ethanol on the antibacterial properties of 2% chlorexidine (CHX) over monospecies biofilm (Enterococcus faecalis) through a culture-based method, and over multispecies biofilm using confocal laser scanning microscopy (CLSM). For monospecies model, E. faecalis biofilm was induced in 40 root canals. The irrigation procedures were: S-saline solution; S/CHX-saline solution + CHX; E-ethanol; and E/CHX-ethanol + CHX. Microbial sampling was performed at three periods: before (S1), immediately after (S2), and 72 h after the final flush (S3). For multispecies biofilm model, 28 sterilized bovine dentin blocks were fixed on a removable orthodontic device to allow intraoral biofilm development. Seven samples were used in each group. Statistical analysis was carried out by using the Kruskal-Wallis test and Dunn's test for multiple comparisons. There was a significant reduction in CFUs count immediately after the final flush (S2) in all experimental groups (P < 0.05). However, only S/CHX, E and E/CHX groups had CFU counts close to zero, without differences among them (P > 0.05). After 72h (S3), the S/CHX and E/CHX groups had CFU counts near zero (P > 0.05). The CFU count increased in S3 for S and E groups (P < 0.05). CLSM showed that the percentages of remaining live cells were similar in S/CHX, E, and E/CHX groups (P > 0.05). The S group had the highest percentage of live cells (P < 0.05). The 95% ethanol did not interfere in the antibacterial properties of 2% CHX over mono- and multispecies biofilms. PMID:26138134

  10. Definition of Mycobacterium tuberculosis culture filtrate proteins by two-dimensional polyacrylamide gel electrophoresis, N-terminal amino acid sequencing, and electrospray mass spectrometry.

    PubMed Central

    Sonnenberg, M G; Belisle, J T

    1997-01-01

    A number of the culture filtrate proteins secreted by Mycobacterium tuberculosis are known to contribute to the immunology of tuberculosis and to possess enzymatic activities associated with pathogenicity. However, a complete analysis of the protein composition of this fraction has been lacking. By using two-dimensional polyacrylamide gel electrophoresis, detailed maps of the culture filtrate proteins of M. tuberculosis H37Rv were generated. In total, 205 protein spots were observed. The coupling of this electrophoretic technique with Western blot analysis allowed the identification and mapping of 32 proteins. Further molecular characterization of abundant proteins within this fraction was achieved by N-terminal amino acid sequencing and liquid chromatography-mass spectrometry. Eighteen proteins were subjected to N-group analysis; of these, only 10 could be sequenced by Edman degradation. Among the most interesting were a novel 52-kDa protein demonstrating significant homology to an alpha-hydroxysteroid dehydrogenase of Eubacterium sp. strain VPI 12708, a 25-kDa protein corresponding to open reading frame 28 of the M. tuberculosis cosmid MTCY1A11, and a 31-kDa protein exhibiting an amino acid sequence identical to that of antigen 85A and 85B. This latter product migrated with an isoelectric point between those of antigen 85A and 85C but did not react with the antibody specific for this complex, suggesting that there is a fourth member of the antigen 85 complex. Novel N-terminal amino acid sequences were obtained for three additional culture filtrate proteins; however, these did not yield significant homology to known protein sequences. A protein cluster of 85 to 88 kDa, recognized by the monoclonal antibodies IT-57 and IT-42 and known to react with sera from a large proportion of tuberculosis patients, was refractory to N-group analysis. Nevertheless, mass spectrometry of peptides obtained from one member of this complex identified it as the M. tuberculosis Kat

  11. Improving Cognition: A Multi-Cultural Approach. Final Report, MICA Project: Multi-Cultural Improvement of Cognitive Abilities.

    ERIC Educational Resources Information Center

    De Avila, Edward; And Others

    Described and summarized are the results of a program designed to improve the intellectual, academic, and linguistic functioning of children in a linguistically and culturally mixed setting. The program, Multicultural Improvement of Cognitive Abilities (MICA), was installed and supported by project staff in nine participating classrooms under two…

  12. The Satellite Development Project in French Language & Culture: France-TV Magazine. FIPSE Final Report.

    ERIC Educational Resources Information Center

    Duverlie, Claud; Pease, Elizabeth

    In 1987, a project was undertaken to expand and further develop "France-TV Magazine," a French language and culture video magazine series featuring cultural and political topics and current events taken from actual French television broadcasts. The project addressed needs for the following: (1) culturally authentic, timely, live materials; (2)…

  13. Cultural Tools and Learning Processes in a Changing World. Final Report to the Spencer Foundation.

    ERIC Educational Resources Information Center

    Greenfield, Patricia M.

    This research study centers on the interrelations among culture, social change, informal education, and cognitive development. The study explored how changing cultural and social conditions influence processes of informal education and their cognitive consequences. The overall goal was to examine the relationship between important cultural tools,…

  14. Cultural resources in the southern Lake Erie Basin: a predictive study. Final report

    SciTech Connect

    Curtis, S.A.; Hatch, J.W.; Bebrich, C.A.; Beckerman, I.C.; Hamilton, C.E.

    1981-01-01

    The text of this study has been structured around three basic themes: (1) the presentation of substantive findings that resulted from a review of the cultural-historical and environmental literature; (2) recommendations based on federal and state regulatory controls concerning the management of cultural resources in the Lake Erie Basin; and (3) the use of a conceptual framework--the cultural-ecological approach--to structure the collection and presentation of substantive findings and to provide a scientific basis for cultural resource management.

  15. The impact of oxygen on the final alcohol content of wine fermented by a mixed starter culture.

    PubMed

    Morales, Pilar; Rojas, Virginia; Quirós, Manuel; Gonzalez, Ramon

    2015-05-01

    We have developed a wine fermentation procedure that takes advantage of the metabolic features of a previously characterized Metschnikowia pulcherrima strain in order to reduce ethanol production. It involves the use of M. pulcherrima/Saccharomyces cerevisiae mixed cultures, controlled oxygenation conditions during the first 48 h of fermentation, and anaerobic conditions thereafter. The influence of different oxygenation regimes and initial inoculum composition on yeast physiology and final ethanol content was studied. The impact of oxygenation on yeast physiology goes beyond the first aerated step and influences yields and survival rates during the anaerobic stage. The activity of M. pulcherrima in mixed oxygenated cultures resulted in a clear reduction in ethanol yield, as compared to S. cerevisiae. Despite relatively low initial cell numbers, S. cerevisiae always predominated in mixed cultures by the end of the fermentation process. Strain replacement was faster under low oxygenation levels. M. pulcherrima confers an additional advantage in terms of dissolved oxygen, which drops to zero after a few hours of culture, even under highly aerated conditions, and this holds true for mixed cultures. Alcohol reduction values about 3.7 % (v/v) were obtained for mixed cultures under high aeration, but they were associated to unacceptable volatile acidity levels. In contrast, under optimized conditions, only 0.35 g/L acetic acid was produced, for an alcohol reduction of 2.2 % (v/v), and almost null dissolved oxygen during the process. PMID:25582558

  16. Sucrose release from polysaccharide gels.

    PubMed

    Nishinari, Katsuyoshi; Fang, Yapeng

    2016-05-18

    Sucrose release from polysaccharide gels has been studied extensively because it is expected to be useful in understanding flavour release from solid foods and to find a new processing method which produces more palatable and healthier foods. We provide an overview of the release of sucrose and other sugars from gels of agar and related polysaccharides. The addition of sucrose to agar solutions leads to the increase in transparency of the resulting gels and the decrease in syneresis, which is attributed to the decrease in mesh size in gels. The syneresis occurring in the quiescent condition and fluid release induced by compression is discussed. The relationship between the sugar release and the structural, rheological and thermal properties of gels is also discussed. Finally, the future research direction is proposed. PMID:26952168

  17. Environmental guidelines for development of Cultural Resource Management plans. Final report

    SciTech Connect

    1995-08-01

    The purpose of this document is to provide guidelines to the DOE field managements with responsibility for the development of an individual Cultural Resource Management Plan for each DOE facility and program.

  18. Medical Devices; Obstetrical and Gynecological Devices; Classification of the Intravaginal Culture System. Final order.

    PubMed

    2016-01-01

    The Food and Drug Administration (FDA) is classifying the intravaginal culture system into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the intravaginal culture system's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device. PMID:26742184

  19. Antimicrobial Peptide P60.4Ac-Containing Creams and Gel for Eradication of Methicillin-Resistant Staphylococcus aureus from Cultured Skin and Airway Epithelial Surfaces.

    PubMed

    Haisma, Elisabeth M; Göblyös, Anikó; Ravensbergen, Bep; Adriaans, Alwin E; Cordfunke, Robert A; Schrumpf, Jasmijn; Limpens, Ronald W A L; Schimmel, Kirsten J M; den Hartigh, Jan; Hiemstra, Pieter S; Drijfhout, Jan Wouter; El Ghalbzouri, Abdoelwaheb; Nibbering, Peter H

    2016-07-01

    We previously found the LL-37-derived peptide P60.4Ac to be effective against methicillin-resistant Staphylococcus aureus (MRSA) on human epidermal models (EMs). The goal of this study was to identify the preferred carrier for this peptide for topical application on skin and mucosal surfaces. We prepared P60.4Ac in three formulations, i.e., a water-in-oil cream with lanolin (Softisan 649), an oil-in-water cream with polyethylene glycol hexadecyl ether (Cetomacrogol), and a hydroxypropyl methylcellulose (hypromellose) 4000 gel. We tested the antimicrobial efficacy of the peptide in these formulations against mupirocin-resistant and -sensitive MRSA strains on EMs and bronchial epithelial models (BEMs). The cytotoxic effects of formulated P60.4Ac on these models were determined using histology and WST-1 and lactate dehydrogenase assays. Moreover, we assessed the stability of the peptide in these formulations with storage for up to 3 months. Killing of MRSA by P60.4Ac in the two creams was less effective than that by P60.4Ac in the hypromellose gel. In agreement with those findings, P60.4Ac in the hypromellose gel was highly effective in eradicating the two MRSA strains from EMs. We found that even 0.1% (wt/wt) P60.4Ac in the hypromellose gel killed >99% of the viable planktonic bacteria and >85% of the biofilm-associated bacteria on EMs. Hypromellose gels containing 0.1% and 0.5% (wt/wt) P60.4Ac effectively reduced the numbers of viable MRSA cells from BEMs by >90%. No cytotoxic effects of P60.4Ac in the hypromellose gel with up to 2% (wt/wt) P60.4Ac on keratinocytes in EMs and in the hypromellose gel with up to 0.5% (wt/wt) P60.4Ac on epithelial cells in BEMs were observed. High-performance liquid chromatography analysis showed that P60.4Ac was stable in the Softisan cream and the hypromellose gel but not in the Cetomacrogol cream. We conclude that P60.4Ac formulated in hypromellose gel is both stable and highly effective in eradicating MRSA from colonized EMs and

  20. Aerosol gels

    NASA Technical Reports Server (NTRS)

    Sorensen, Christopher M. (Inventor); Chakrabarti, Amitabha (Inventor); Dhaubhadel, Rajan (Inventor); Gerving, Corey (Inventor)

    2010-01-01

    An improved process for the production of ultralow density, high specific surface area gel products is provided which comprises providing, in an enclosed chamber, a mixture made up of small particles of material suspended in gas; the particles are then caused to aggregate in the chamber to form ramified fractal aggregate gels. The particles should have a radius (a) of up to about 50 nm and the aerosol should have a volume fraction (f.sub.v) of at least 10.sup.-4. In preferred practice, the mixture is created by a spark-induced explosion of a precursor material (e.g., a hydrocarbon) and oxygen within the chamber. New compositions of matter are disclosed having densities below 3.0 mg/cc.

  1. Bioengineering Aspects of Inorganic Carbon Supply to Mass Algal Cultures: Final Report

    SciTech Connect

    Goldman, J. C.

    1981-04-01

    Regardless of the application, the basic biotechnology of large-scale outdoor cultures involves many common features, particularly in the requirement for adequate nutrients such as carbon, nitrogen, and phosphorus to ensure that light is the sole limiting yield determinant. Whereas the required quantities of nitrogen and phosphorus are fairly simple, to estimate, those for inorganic carbon are far more complex.

  2. Education for Humanistic, Ethical/Moral and Cultural Values: Final Report of a Regional Meeting.

    ERIC Educational Resources Information Center

    National Inst. for Educational Research, Tokyo (Japan).

    This report stems from a meeting of representatives of countries in the Asia Pacific region concerned with the development of strategies for strengthening content relating to humanistic, ethical, and cultural values in formal and non-formal education. The following countries were represented: Australia, Bangladesh, China, India, Indonesia, Japan,…

  3. AN EVALUATION OF A PRESCHOOL TRAINING PROGRAM FOR CULTURALLY DEPRIVED CHILDREN. FINAL REPORT.

    ERIC Educational Resources Information Center

    TAMMINEN, ARMAS W.; AND OTHERS

    TO FIND OUT IF CULTURALLY DEPRIVED CHILDREN SHOW CHANGE IN ACADEMIC READINESS AS A RESULT OF SPECIAL PRESCHOOL PROGRAMS, 3 GROUPS OF CHILDREN (14 TO 17 IN EACH) IN 3 DULUTH SCHOOL AREAS WERE PRE- AND POSTTESTED WITH THE STANFORD-BINET AND SRA PRIMARY MENTAL ABILITIES TESTS. A CONTROL GROUP OF 30 CHILDREN FROM THE SAME 3 SCHOOL AREAS WERE GIVEN THE…

  4. Teacher Attitudes Toward Professionalism, Job Satisfaction and Collective Negotiations: A Cross Cultural-Study. Final Report.

    ERIC Educational Resources Information Center

    Peterson, Richard B.

    This research explores the interrelationships between the attitudinal variables of job satisfaction, professionalism, and collective negotiations within a cross-cultural context. Questionnaires were developed and sent to over 2,000 public school teachers and principals (primarily secondary school level) in the State of Washington and Sweden.…

  5. African American and Youth Culture as a Bridge To Writing Development. Final Report.

    ERIC Educational Resources Information Center

    Mahiri, Jabari

    A study examined whether the familiarity and competence that many African American students have with elements of rap music and culture could be used as a bridge to the production of other literate texts. Two high-school English teachers, one teaching at Fremont High School, East Oakland and the other teaching at Berkeley High School in Berkeley,…

  6. The Effect of Role Playing by the Culturally Disadvantaged on Attitudes toward Bidialectalism. Final Report.

    ERIC Educational Resources Information Center

    Brandes, Paul D.

    In an effort to motivate culturally different students to learn standard English while they remain proud of their dialect and retain it as their informal manner of speaking, 120 blacks at three grade levels role played from scripts the parts of employers, college admissions officers, and applicants. The scripts rewarded applicants who could and…

  7. Culture.

    ERIC Educational Resources Information Center

    1997

    Twelve conference papers on cultural aspects of second language instruction include: "Towards True Multiculturalism: Ideas for Teachers" (Brian McVeigh); Comparing Cultures Through Critical Thinking: Development and Interpretations of Meaningful Observations" (Laurel D. Kamada); "Authority and Individualism in Japan and the USA" (Alisa Woodring);…

  8. Cross-cultural equivalence in translation of the oral health impact profile: how to interpret the final score?

    PubMed

    Denis, Frederic; Trojak, Benoit; Rude, Nathalie

    2016-06-01

    The oral health impact profile (OHIP) is one of the most widely known oral health-related quality of life instruments. In Community Dentistry and Oral Epidemiology, MacEntee and Brondani report the results of a systematic review to identify acceptable methods for translating psychometric instruments for cross-cultural equivalence of the OHIP scale. But in no study has unidimensionality, one aspect of the validity of the internal structure of the scale, been verified, whereas it is a major psychometric step. In the absence of the study of unidimensionality, it is difficult to interpret the final score. The methodology of transcultural validation of the OHIP could be improved, and the study of the unidimensionality is a psychometrically necessary step for the interpretation of the finale score. PMID:26879212

  9. Culturally relevant science: An approach to math science education for hispanics. Final technical report

    SciTech Connect

    Montellano, B.O. de

    1996-11-14

    This progress report summarizes results of a teacher workshop. A letter sent to 17 teachers who had participated in the workshop requested a report of any activities undertaken and copies of lesson plans and materials developed. Only nine responses were received, and not all of them demonstrated a satisfactory level of activity. Teachers who submitted materials showing the most promise were invited to participate in the Summer Writing Workshop. A partial first draft of a companion volume for the teacher`s manual was written which provides a rationale for culturally relevant science and presents the cultural and scientific background needed. The outline of the book is presented in Appendix 1. Appendix 2 is a sample chapter from the book.

  10. Cellular heredity in haploid cultures of somatic cells, March 1968-April 1981. Final report

    SciTech Connect

    Freed, J.J.

    1982-03-01

    An account is given of the development and application to cell-culture genetics of unique haploid cell lines from frog embryo developed in this laboratory. Since 1968, the main aim of this project has been to develop the haploid cell system for studies of mutagenesis in culture, particularly by ultraviolet radiation. In the course of this work we isolated chromosomally stable cell lines, derived and characterized a number of variants, and adapted cell hybridization and other methods to this material. Particular emphasis was placed on ultraviolet photobiology, including studies of cell survival, mutagenesis, and pathways of repair of uv-damaged DNA. Although at present less widely used for genetic experiments than mammalian cell lines, the frog cells offer the advantages of authentic haploidy and a favorable repertory of DNA repair pathways for study of uv mutagenesis.

  11. Bioengineering aspects of inorganic carbon supply to mass algal cultures. Final report

    SciTech Connect

    Goldman, J.C.

    1980-06-01

    The work included in this report is part of an ongoing study (currently funded by the Solar Energy Research Institute - Subcontract No. XR-9-8144-1) on the inorganic carbon requirements of microalgae under mass culture conditions and covers the period June 1, 1978 through May 31, 1979. It is divided into two parts appended herein. The first part is a literature review on the inorganic carbon chemical system in relation to algal growth requirements, and the second part deals with the kinetics of inorganic carbon-limited growth of two freshwater chlorophytes including the effect of carbon limitation on cellular chemical composition. Additional experiment research covered under this contract was reported in the Proceedings of the 3rd Annual Biomass Energy Systems Conferences, pp. 25-32, Bioengineering aspects of inorganic carbon supply to mass algal cultures. Report No. SERI/TP-33-285.

  12. Rational Synthesis of Imprinted Organofunctional Sol-Gel Materials for Toxic Metal Separation - Final Report - 09/15/1997 - 09/14/2001

    SciTech Connect

    Xue, Ziling; Barnes, Craig E.; Dai, Shang

    2001-09-14

    Current cost estimates for the environmental remediation of contaminated installations under the auspices of the Department of Energy (DOE) are staggering. On this basis alone, there is a critical need to develop the scientific basis for new approaches to the treatment and disposal of toxic metal ions from wastes or contaminated areas at many DOE sites. The overall goal of this project is to rationally design and synthesize imprinted, hybrid inorganic-organic sol-gel materials containing metal binding sites through template approaches, and to develop a scientific basis for metal ion binding and recognition by such tailored hybrid inorganic-organic materials. After removal of the template M, functionalized cavities are created which contain both grafted binding sites and functionality inherent to the silica network (Si-OH, Si-O-Si). These cavities are expected to ''recognize'' and bind the target metal ions through the high affinities between the binding sites and M, and their retained shapes. Our approaches utilize both the metal ion binding and the tailored impressions of the template metal ions in the imprinted cavities. Such imprinted organofunctional sol-gel networks are expected to exhibit both high selectivity and capacity for binding targeted ions in fluid waste streams. The principles of sol-gel chemistry and imprinting techniques will guide our approaches to optimize the chemical and physical properties of the imprinted organofunctional sol-gel materials. Cold isotopes or non-radioactive surrogate ions of similar size and charge will be used in imprinting investigations to minimize hazardous waste production. The design strategy we will follow is based on imprinted binding sites cross-linked by rigid, hydrophilic inorganic SiO{sub 2} or MiO{sub 2} networks. These hydrophilic metal oxide-based materials are expected to exhibit fast ion mass transfer and binding kinetics in comparison to functionalized hydrophobic organic polymers. Success in this research

  13. Columbia River System Operation Review : Final Environmental Impact Statement, Appendix D: Cultural Resources.

    SciTech Connect

    Columbia River System Operation Review

    1995-11-01

    This study attempts to identify and analyze the impacts of the System Operating Strategy (SOS) alternatives on cultural resources. The impacts include effects on Native American traditional cultural values, properties and practices. They also include effects on archeological or historic properties meeting the criteria of the National Register of Historic Places. In addition to responding to the requirements of the National Environmental Policy Act (NEPA), this analysis addresses the requirements of the National Historic Preservation Act (NHPA), the Archeological Resources Protection Act (ARPA), the Native American Graves Protection and Repatriation Act (NAGPRA), the Native American Religious Freedom Act (NARFA), and other relevant legislation. To meet their legally mandated cultural resources requirements, the SOR agencies will develop agreements and Implementation Plans with the appropriate State Historic Preservation Officers (SHPOs), Tribes, and the Advisory Council on Historic Preservation (ACHP) detailing the measures necessary to best manage the resource. The planning and implementation activities will be staged over a number of years in consultation with affected Tribes.

  14. Cultural Conflict and Integration in the Andes: Final Report to the National Endowment for the Humanities.

    ERIC Educational Resources Information Center

    Paulston, Rolland G.

    This final report discusses objectives and proceedings of the Andean Studies Institute held during the summer of 1972 and sponsored by the Center for Latin American Studies. Methods and activities undertaken in the pursuit of the program objectives are described. It is suggested that future language-study institutes be combined with area-studies…

  15. Networking with Historically Black Colleges and Universities: Cultural Diversity in Public Administration Education at Indiana State University. A Final Report on a Cultural Diversity Innovation in Public Administration Education Project, 1992-1993.

    ERIC Educational Resources Information Center

    Mohapatra, Manindra K.; McDowell, James L.

    This final report describes a Cultural Diversity Innovation project implemented in 1992-93 at Indiana State University (ISU). The central objective of the project was to enrich cultural diversity elements in the Masters in Public Administration (MPA) curriculum at ISU through the presentations of visiting faculty from historically black colleges…

  16. Cell response to silica gels with varying mechanical properties

    NASA Astrophysics Data System (ADS)

    Lefebvre, Molly Ann

    Sol-gel encapsulation has a variety of applications in biotechnology and medicine: creating biosensors, biocatalysts, and bioartificial organs. However, encapsulated cell viability is a major challenge. Consequently, interactions between cells and their 3D microenvironment were studied through rheological, metabolic activity, and extraction studies to aid in the development of new gel protocols. The cells were encapsulated in variations of three silica sol-gels with varying stiffness. It was hypothesized that the cell viability and the amount of extracted cells would depend on gel stiffness. For two gels, there was no apparent correlation between the gel stiffness and the cell viability and extracted cell quantity. These gels did strongly depend on the varying gel ingredient, polyethylene glycol. The third gel appeared to follow the hypothesized correlation, but it was not statistically significant. Finally, one gel had a significantly longer period of cell viability and higher quantity of extracted cells than the other gels.

  17. Culturally relevant science: An approach to math science education for Hispanics. Final technical report

    SciTech Connect

    Ortiz de Montellano, B.

    1996-11-14

    As planned a letter was sent out to 17 teachers who had participated in a Summer 1994 workshop on ``Culturally Relevant Science for Hispanics`` at Michigan State. These teachers were supposed to have spent the intervening time developing lesson plans and curricula. The letter requested a report of any activities undertaken and copies of lesson plans and materials developed by February 1996 with a stipend of $400 for satisfactory reports. It was a disappointment to only get 9 responses and not all of them demonstrating a satisfactory level of activity. Diana Marinez, Dean of Science at Texas A and M University, Corpus Christi, who is the other developer of this curriculum and the author reviewed the submitted materials and chose those showing the most promise to be invited to participate in the Summer Writing Workshop. Spring of 1996 and particularly in May--June, the author wrote a partial first draft of a companion volume for the teacher`s manual which would provide a rationale for doing culturally relevant science, present the cultural and the scientific background that teachers would need in order to be able to teach. One of the goals of this curriculum is that it should be off-the-shelf ready to teach and that teachers would not have to do extra research to encourage its adoption. The outline of the book is appendix 1. The Writing Workshop was held at Texas A and M University, Corpus Christi from July 14 to July 27, 1996. Participating teachers chose topics that they were interested in developing and wrote first drafts. These were distributed to all participants and critiqued by the workshop directors before being rewritten. Some teachers were more productive than others depending on their science background. In total an impressive number of lesson plans were written. These lesson plans are listed in Appendix 3. Appendix 4 is a sample lesson. Work still needs to be done on both the source book and the teachers` manual.

  18. Historic, enthnohistoric and prehistoric cultural resource inventory. Final technical report, November 1980-May 1982

    SciTech Connect

    Not Available

    1982-01-01

    The goal of this study is to provide a literature search and write a historical narrative of the cultural significance of the study area for the proposed WyCoalGas Inc., pipeline, railroad, well fields, and coal gasification plant. The request for a cultural resource investigation states at a minimum the study shall be a literature search on the narrow one mile corridor along the proposed pipelines, areas included within the various facilities plus a one mile buffer surrounding these facilities. In addition, the study must be tied into appropriate local, state, and national history. The writer of this history has felt a responsibility for providing a realistic assessment of the themes of the study area's historical development. Several ideas have been concentrated upon: its American Indian heritage; the Euro-American's exploitive relationship with the region; and the overriding fragile, arid nature of its land. It is hoped that the government agencies and ultimately the energy company will feel a similiar responsibility toward the study area's historical integrity.

  19. The morphology, proliferation rate, and population doubling time factor of adipose-derived mesenchymal stem cells cultured on to non-aqueous SiO2, TiO2, and hybrid sol-gel-derived oxide coatings.

    PubMed

    Marycz, Krzysztof; Krzak-Roś, Justyna; Donesz-Sikorska, Anna; Śmieszek, Agnieszka

    2014-11-01

    In recent years, much attention has been paid to the development of tissue engineering and regenerative medicine, especially when stem cells of various sources are concerned. In addition to the interest in mesenchymal stem cells isolated from bone marrow, recently more consideration has been given to stem cells isolated from adipose tissue (AdMSCs), due to their less invasive method of collection as well as their ease of isolation and culture. However, the development of regenerative medicine requires both the application of biocompatible material and the stem cells to accelerate the regeneration. In this study, we investigated the morphology, proliferation rate index (PRi), and population doubling time factor of adipose-derived mesenchymal stem cells cultured on non-aqueous sol-gel-derived SiO2, TiO2, and SiO2/TiO2 oxide coatings. The results indicated an increase in PRi of AdMSCs when cultured on to titanium dioxide, suggesting its high attractiveness for AdMSCs. In addition, the proper morphology and the shortest doubling time of AdMSCs were observed when cultured on titanium dioxide coating. PMID:24408867

  20. Environmental transformations and cultural changes: A multidisciplinary case study for the Late Glacial and Final Palaeolithic from Northern Germany

    NASA Astrophysics Data System (ADS)

    Turner, F.; Tolksdorf, J. F.; Viehberg, F.; Schwarz, A.; von Bramann, U.; Bittmann, F.; Kaiser, K.; Schwalb, A.; Staesche, U.; Breest, K.; Pott, R.; Veil, S.

    2012-04-01

    In contrast to younger periods, studies integrating archaeological and environmental records for the Palaeolithic are still rare. Especially our knowledge about interactions between the drastic climatic/environmental changes and cultural developments during the Late Glacial is very limited. This multidisciplinary case study from river Jeetzel, a western Elbe tributary in Northern Germany, combines high resolution palaeoenvironmental investigations with fine-scaled archaeological research on stratified and surface sites. Various dating methods (palynostratigraphy, radiocarbon- and OSL-dating) and analyses of environmental and climatological proxies (pollen and plant macro-remains, ostracods, diatoms and green algae) on river palaeochannel sediments allow detailed reconstruction of interactions between Late Glacial climate, vegetation and fluvial developments. Biostratigraphical analyses on stratified archaeological sites and dating of charcoal / bone fragments from artefact scatters place the Late Palaeolithic occupation of Early Federmesser groups in an environmental context. Thus the former production of hitherto unknown amber art (amongst others a figurine representing a moose) can be ascribed to the Older Dryas and Early Allerød, which are the periods of main Late Glacial afforestation. Therewith our investigations suggest that Final Palaeolithic cultural changes may have been triggered by climatic and environmental transformations.

  1. Variations in microbicide gel acceptability among young women in the USA and Puerto Rico.

    PubMed

    Giguere, Rebecca; Carballo-Diéguez, Alex; Ventuneac, Ana; Mabragaña, Marina; Dolezal, Curtis; Chen, Beatrice A; Kahn, Jessica A; Zimet, Gregory D; McGowan, Ian

    2012-01-01

    In a multi-site study of vaginal microbicide acceptability conducted with sexually active young women, quantitative assessments revealed significant differences in acceptability by site. Participants in Puerto Rico rated the gel more favourably than mainland US participants in terms of liking the gel and likelihood of future use. To explain these differences, we examined responses to qualitative behavioural assessments. Young women in mainland USA associated gel leakage with uncomfortable sensations experienced during menstruation, while young women in Puerto Rico had positive associations of gel use with douching. These negative or positive associations affected assessments of the gel's physical qualities. In addition, young women's perceptions of primary partners' support for microbicide use influenced sexual satisfaction with the gel and, ultimately, product acceptability. Finally, geographic HIV-risk context contributed to heightened HIV-risk perception, which influenced likelihood of future microbicide use, even for women in stated monogamous relationships. Future microbicide acceptability studies should take into account potential differences in acceptability by site such as HIV-risk perception based on local HIV prevalence, popularity of vaginal hygiene products in a specific area and male attitudes in different cultures concerning women's use of HIV protection strategies. PMID:22084840

  2. Construction of Mesenchymal Stem Cell–Containing Collagen Gel with a Macrochanneled Polycaprolactone Scaffold and the Flow Perfusion Culturing for Bone Tissue Engineering

    PubMed Central

    Yu, Hye-Sun; Won, Jong-Eun; Jin, Guang-Zhen

    2012-01-01

    Abstract A novel bone tissue-engineering construct was developed by using poly(ɛ-caprolactone) (PCL)-macrochanneled scaffolds combined with stem cell-seeded collagen hydrogels and then applying flow perfusion culture. Rat mesenchymal stem cells (MSCs) were loaded into collagen hydrogels, which were then combined with macrochanneled PCL scaffolds. Collagen hydrogels were demonstrated to provide favorable growth environments for MSCs and to foster proliferation. Cell number determination identified retention of substantially fewer (50–60%) cells when they were seeded directly onto macrochanneled PCL than of cells engineered within collagen hydrogels. Additionally, the cells actively proliferated within the combined scaffold for up to 7 days. MSC-loaded collagen–PCL scaffolds were subsequently cultured under flow perfusion to promote proliferation and osteogenic differentiation. Cells proliferated to levels significantly higher in flow perfusion culture than that under static conditions during 21 days. A quantitative polymerase chain reaction (QPCR) assay revealed significant alterations in the transcription of bone-related genes such as osteopontin (OPN), osteocalcin (OCN), and bone sialoprotein (BSP), such as 8-, 2.5-, and 3-fold induction, respectively, after 10 days of flow perfusion relative to those in static culture. OPN and OCN protein levels, as determined by Western blot, increased under flow perfusion. Cellular mineralization was significantly enhanced by the flow perfusion during 21 and 28 days. Analyses of mechanosensitive gene expression induced by flow perfusion shear stress revealed significant upregulation of c-fos and cyclooxygenase-2 (COX-2) during the initial culture period (3–5 days), suggesting that osteogenic stimulation was possible as a result of mechanical force-driven transduction. These results provide valuable information for the design of a new bone tissue-engineering system by combining stem cell-loaded collagen hydrogels with

  3. The DOE subsurface microbial culture collection at Florida State University. Final technical report, January 16, 1996--February 15, 1997

    SciTech Connect

    Balkwill, D.L.

    1998-05-25

    This report describes the research that supports the Subsurface Science Program by maintaining a culture collection of microorganisms isolated from deep terrestrial subsurface environments (the Subsurface Microbial Culture Collection, or SMCC). The general distribution of cultures and data was identified as an important function of the SMCC. The accomplishments related to this function of the culture collection are described.

  4. Native Hawaiians Study Commission: Report on the Culture, Needs and Concerns of Native Hawaiians. Final Report. Volume II. Claims of Conscience: A Dissenting Study of the Culture, Needs and Concerns of Native Hawaiians.

    ERIC Educational Resources Information Center

    Department of the Interior, Washington, DC.

    Volume II of the final report of the Native Hawaiians Study Commission (NHSC) on the culture, needs, and concerns of native Hawaiians, this book contains a formal dissent to the conclusions and recommendations presented in Volume I made by three of the NHSC commissioners. Its principal criticism is that Volume I fails to address the underlying…

  5. Culturally Oriented Instructional Materials for Pima Children. Final Report, Academic Year 1969-70, for an Elementary and Secondary Education Act Title III Project.

    ERIC Educational Resources Information Center

    Brook, Weston L., Comp.

    Culturally oriented instructional materials for Pima children are described in this final report of a 3-year study funded by the Elementary and Secondary Education Act, Title III. The reported objective of the project was to assist the Pima children living on the Gila River Indian Reservation in Arizona to develop a positive self-image and a sense…

  6. Native Hawaiians Study Commission: Report on the Culture, Needs and Concerns of Native Hawaiians, Pursuant to Public Law 96-565, Title III. Final Report. Volume I.

    ERIC Educational Resources Information Center

    Department of the Interior, Washington, DC.

    The findings and recommendations of a 21-month study of the culture, needs, and concerns of native Hawaiians are presented in this final report, the first volume of a report commissioned by the United States Congress. Following a brief description of the approach and methodology used and the executive summary, part I deals with socioeconomic and…

  7. The CDCC's Project No. 7: "The Education and Cultural Development of Migrants." Final Conference (Rotterdam, Netherlands, April 7-11, 1986).

    ERIC Educational Resources Information Center

    van den Berg-Eldering, Lotty

    This report summarizes the proceedings of the final conference of Project No. 7 to develop an inter-cultural approach to the education of migrants. An introductory section outlines conference aims and remarks by opening/closing speakers. Section II describes conference visits to schools in Rotterdam and an adult education project and a center for…

  8. Fundamentals of gel dosimeters

    NASA Astrophysics Data System (ADS)

    McAuley, K. B.; Nasr, A. T.

    2013-06-01

    Fundamental chemical and physical phenomena that occur in Fricke gel dosimeters, polymer gel dosimeters, micelle gel dosimeters and genipin gel dosimeters are discussed. Fricke gel dosimeters are effective even though their radiation sensitivity depends on oxygen concentration. Oxygen contamination can cause severe problems in polymer gel dosimeters, even when THPC is used. Oxygen leakage must be prevented between manufacturing and irradiation of polymer gels, and internal calibration methods should be used so that contamination problems can be detected. Micelle gel dosimeters are promising due to their favourable diffusion properties. The introduction of micelles to gel dosimetry may open up new areas of dosimetry research wherein a range of water-insoluble radiochromic materials can be explored as reporter molecules.

  9. SisterTalk: final results of a culturally tailored cable television delivered weight control program for Black women

    PubMed Central

    2013-01-01

    Background Obesity among Black women continues to exceed that of other women. Most weight loss programs created without reference to specific cultural contexts are less effective for Black than White women. Weight control approaches accessible to Black women and adapted to relevant cultural contexts are important for addressing this problem. This paper reports the final results of SisterTalk, the randomized controlled trial of a cable TV weight control program oriented toward Black women. Methods A five group design included a comparison group and a 2 × 2 factorial comparison of a) interactive vs. passive programming and b) telephone social support vs no telephone support, with 12 weekly initial cable TV programs followed by 4 monthly booster videos. At baseline, 3, 8, and 12 months post randomization, telephone and in person surveys were administered on diet, physical activity, and physical measurements of height and weight were taken to calculate body mass index (BMI). Analysis of variance (ANOVA) was used to examine differences over time, and between treatment and comparison groups. Dose variables reflecting use of the TV/video and written materials were also assessed. Results At 3 months, BMI, weight, and dietary fat were significantly lower and physical activity significantly higher among women exposed to the Cable TV intervention compared to the wait-list comparison group. Significant dietary fat differences were still observed at 8 and 12 month evaluations, but not BMI or physical activity differences. Main effects were not observed for interactive programming or enhanced social support at any time point. Within the intervention group, higher watching of the TV series and higher reading of educational materials were both (separately) associated with significantly lower dietary fat. Conclusions Cable TV was an effective delivery channel to assist Black women with weight control, increasing physical activity and decreasing dietary fat during an initial

  10. Testosterone Nasal Gel

    MedlinePlus

    Testosterone nasal gel is used to treat symptoms of low testosterone in men who have hypogonadism (a condition in which the body does not produce enough natural testosterone). Testosterone nasal gel is used only for men ...

  11. Identification of bacteria in enrichment cultures of sulfate reducers in the Cariaco Basin water column employing Denaturing Gradient Gel Electrophoresis of 16S ribosomal RNA gene fragments

    PubMed Central

    2013-01-01

    Background The Cariaco Basin is characterized by pronounced and predictable vertical layering of microbial communities dominated by reduced sulfur species at and below the redox transition zone. Marine water samples were collected in May, 2005 and 2006, at the sampling stations A (10°30′ N, 64°40′ W), B (10°40′ N, 64°45′ W) and D (10°43’N, 64°32’W) from different depths, including surface, redox interface, and anoxic zones. In order to enrich for sulfate reducing bacteria (SRB), water samples were inoculated into anaerobic media amended with lactate or acetate as carbon source. To analyze the composition of enrichment cultures, we performed DNA extraction, PCR-DGGE, and sequencing of selected bands. Results DGGE results indicate that many bacterial genera were present that are associated with the sulfur cycle, including Desulfovibrio spp., as well as heterotrophs belonging to Vibrio, Enterobacter, Shewanella, Fusobacterium, Marinifilum, Mariniliabilia, and Spirochaeta. These bacterial populations are related to sulfur coupling and carbon cycles in an environment of variable redox conditions and oxygen availability. Conclusions In our studies, we found an association of SRB-like Desulfovibrio with Vibrio species and other genera that have a previously defined relevant role in sulfur transformation and coupling of carbon and sulfur cycles in an environment where there are variable redox conditions and oxygen availability. This study provides new information about microbial species that were culturable on media for SRB at anaerobic conditions at several locations and water depths in the Cariaco Basin. PMID:23981583

  12. Sol-gel kinetics by NMR

    SciTech Connect

    Assink, R.A.; Kay, B.D.

    1991-01-01

    The chemical synthesis of advanced ceramic and glass materials by the sol-gel process has become an area of increasing activity in the field of material science. The sol-gel process provides a means to prepare homogeneous, high purity materials with tailored chemical and physical properties. This paper surveyed the nuclear magnetic resonance (NMR) studies of silicon-based sol-gel kinetics. A review of the various models which have been used to analyze the chemical kinetics of various sol-gel systems was presented. The utility of NMR spectroscopy was demonstrated in investigating the influence that various reaction conditions have on the reaction pathways by which sol-gel derived materials are synthesized. By observing in a direct fashion the chemical pathway of the sol-gel, it is often possible to relate the final properties of the material to the formulation and reaction conditions of the sol-gel. The study of reaction kinetics by NMR is expected to play an increasingly important role in understanding sol-gel processing and material properties. 15 refs. (DP)

  13. Statistical physics of polymer gels

    NASA Astrophysics Data System (ADS)

    Panyukov, Sergei; Rabin, Yitzhak

    1996-05-01

    -linked gels becomes increasingly inhomogeneous with the approach to the cross-link saturation threshold at which the heterogeneity parameter diverges. Analytical expressions for the correlators of deformed gels are derived in both the long wavelength and the short wavelength limits and an exact expression for the total static structure factor, valid for arbitrary wavelengths, is obtained for gels in the state of preparation. We adapt the RPA results to gels permeated by free labelled chains and to gels in good solvents (in the latter case, excluded volume effects are taken into account exactly) and make predictions which can be directly tested by scattering and thermodynamic experiments. Finally, we discuss the limitations and the possible extensions of our work.

  14. A Study of Pupil Ethnocentrism toward Pre-Western Eskimo Culture in Relation to Certain Instructional Conditions. Final Report.

    ERIC Educational Resources Information Center

    Martin, David S.

    The study investigated the failure of foreign culture studies to create awareness of human universality. Major objectives were to: (1) analyze the relationship of several independent variables such as sex, intelligence, dogmatism, and socio-economic status to the ethnocentrism expressed by children toward pre-Western Eskimo culture, (2) determine…

  15. Sol-Gel Glasses

    NASA Technical Reports Server (NTRS)

    Mukherjee, S. P.

    1985-01-01

    Multicomponent homogeneous, ultrapure noncrystalline gels/gel derived glasses are promising batch materials for the containerless glass melting experiments in microgravity. Hence, ultrapure, homogeneous gel precursors could be used to: (1) investigate the effect of the container induced nucleation on the glass forming ability of marginally glass forming compositions; and (2) investigate the influence of gravity on the phase separation and coarsening behavior of gel derived glasses in the liquid-liquid immiscibility zone of the nonsilicate systems having a high density phase. The structure and crystallization behavior of gels in the SiO2-GeO2 as a function of gel chemistry and thermal treatment were investigated. As are the chemical principles involved in the distribution of a second network former in silica gel matrix being investigated. The procedures for synthesizing noncrystalline gels/gel-monoliths in the SiO2-GeO2, GeO2-PbO systems were developed. Preliminary investigations on the levitation and thermal treatment of germania silicate gel-monoliths in the Pressure Facility Acoustic Levitator were done.

  16. Multiscale modeling of polyelectrolyte gels

    NASA Astrophysics Data System (ADS)

    Wallmersperger, Thomas; Wittel, Falk K.; Kröplin, Bernd H.

    2006-03-01

    Electrolyte polymer gels are a very attractive class of actuation materials with remarkable electronic and mechanical properties having a great similarity to biological contractile tissues. They consist of a polymer network with ionizable groups and a liquid phase with mobile ions. Absorption and delivery of solvent lead to a considerably large change of volume. Due to this capability, they can be used as actuators for technical applications, where large swelling and shrinkage is desired. In the present work chemically and electrically stimulated polymer gels in a solution bath are investigated. To describe the different complicated phenomena occurring in these gels adequately, the modeling can be conducted on different scales. Therefore, models based on the statistical theory and porous media theory, as well as a multi-field model and a discrete element formulation are derived. A refinement of the different theories from global macroscopic to microscopic are presented in this paper: The statistical theory is a macroscopic theory capable to describe the global swelling or bending e.g. of a gel film, while the general theory of porous media (TPM) is a macroscopic continuum theory which is based on the theory of mixtures extended by the concept of volume fractions. The TPM is a homogenized model, i.e. all geometrical and physical quantities can be seen as statistical averages of the real quantities. The presented chemo-electro-mechanical multi-field formulation is a mesoscopic theory. It is capable of giving the concentrations and the electric potential in the whole domain. Finally the (micromechanical) discrete element (DE) theory is employed. In this case, the continuum is represented by distributed particles with local interaction relations combined with balance equations for the chemical field. This method is predestined for problems involving large displacements, strains and discontinuities. The presented formulations are compared and conclusions on their

  17. Design, Fabrication, and Operation of Innovative Microalgae Culture Experiments for the Purpose of Producing Fuels: Final Report, Phase I

    SciTech Connect

    Not Available

    1985-01-01

    A conceptual design was developed for a 1000-acre (water surface) algae culture facility for the production of fuels. The system is modeled after the shallow raceway system with mixing foils that is now being operated at the University of Hawaii. A computer economic model was created to calculate the discounted breakeven price of algae or fuels produced by the culture facility. A sensitivity analysis was done to estimate the impact of changes in important biological, engineering, and financial parameters on product price.

  18. CONFORMANCE IMPROVEMENT USING GELS

    SciTech Connect

    Randall S. Seright

    2003-09-01

    This report describes work performed during the second year of the project, ''Conformance Improvement Using Gels.'' The project has two objectives. The first objective is to identify gel compositions and conditions that substantially reduce flow through fractures that allow direct channeling between wells, while leaving secondary fractures open so that high fluid injection and production rates can be maintained. The second objective is to optimize treatments in fractured production wells, where the gel must reduce permeability to water much more than that to oil. Pore-level images from X-ray computed microtomography were re-examined for Berea sandstone and porous polyethylene. This analysis suggests that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than a gel-ripping mechanism. This finding helps to explain why aqueous gels can reduce permeability to water more than to oil. We analyzed a Cr(III)-acetate-HPAM gel treatment in a production well in the Arbuckle formation. The availability of accurate pressure data before, during, and after the treatment was critical for the analysis. After the gel treatment, water productivity was fairly constant at about 20% of the pre-treatment value. However, oil productivity was stimulated by a factor of 18 immediately after the treatment. During the six months after the treatment, oil productivity gradually decreased to approach the pre-treatment value. To explain this behavior, we proposed that the fracture area open to oil flow was increased substantially by the gel treatment, followed by a gradual closing of the fractures during subsequent production. For a conventional Cr(III)-acetate-HPAM gel, the delay between gelant preparation and injection into a fracture impacts the placement, leakoff, and permeability reduction behavior. Formulations placed as partially formed gels showed relatively low pressure gradients during placement, and yet substantially reduced the flow capacity of

  19. 3D Cell Culture in Alginate Hydrogels

    PubMed Central

    Andersen, Therese; Auk-Emblem, Pia; Dornish, Michael

    2015-01-01

    This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent), and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell–matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue. PMID:27600217

  20. CONFORMANCE IMPROVEMENT USING GELS

    SciTech Connect

    Randall S. Seright

    2004-03-01

    This technical progress report describes work performed from September 1, 2003, through February 29, 2004, for the project, ''Conformance Improvement Using Gels.'' We examined the properties of several ''partially formed'' gels that were formulated with a combination of high and low molecular weight HPAM polymers. After placement in 4-mm-wide fractures, these gels required about 25 psi/ft for brine to breach the gel (the best performance to date in fractures this wide). After this breach, stabilized residual resistance factors decreased significantly with increased flow rate. Also, residual resistance factors were up to 9 times greater for water than for oil. Nevertheless, permeability reduction factors were substantial for both water and oil flow. Gel with 2.5% chopped fiberglass effectively plugged 4-mm-wide fractures if a 0.5-mm-wide constriction was present. The ability to screen-out at a constriction appears crucial for particulate incorporation to be useful in plugging fractures. In addition to fiberglass, we examined incorporation of polypropylene fibers into gels. Once dispersed in brine or gelant, the polypropylene fibers exhibited the least gravity segregation of any particulate that we have tested to date. In fractures with widths of at least 2 mm, 24-hr-old gels (0.5% high molecular weight HPAM) with 0.5% fiber did not exhibit progressive plugging during placement and showed extrusion pressure gradients similar to those of gels without the fiber. The presence of the fiber roughly doubled the gel's resistance to first breach by brine flow. The breaching pressure gradients were not as large as for gels made with high and low molecular weight polymers (mentioned above). However, their material requirements and costs (i.e., polymer and/or particulate concentrations) were substantially lower than for those gels. A partially formed gel made with 0.5% HPAM did not enter a 0.052-mm-wide fracture when applying a pressure gradient of 65 psi/ft. This result

  1. Type I collagen gel protects murine fibrosarcoma L929 cells from TNFα-induced cell death

    SciTech Connect

    Wang, Hong-Ju; He, Wen-Qi; Chen, Ling; Liu, Wei-Wei; Xu, Qian; Xia, Ming-Yu; Hayashi, Toshihiko; Fujisaki, Hitomi; Hattori, Shunji; Tashiro, Shin-ichi; Onodera, Satoshi; Ikejima, Takashi

    2015-02-20

    Murine fibrosarcoma L929 cells have been used to test efficacy of proinflammatory cytokine TNFα. In the present study, we reported on protective effect of type I collagen gel used as L929 cell culture. L929 cell grew and proliferated well on collagen gel. However, the L929 cells exhibited cobblestone-like morphology which was much different from the spread fusiform shape when cultured on conventional cell dishes as well as the cells tended to aggregate. On conventional cell culture dishes, the cells treated with TNFα became round in shape and eventually died in a necroptotic manner. The cells cultured on collagen gel, however, were completely unaffected. TNFα treatment was reported to induce autophagy in L929 cells on the plastic dish, and therefore we investigated the effect of collagen gel on induction of autophagy. The results indicated that autophagy induced by TNFα treatment was much reduced when the cells were cultured on collagen gel. In conclusion, type I collagen gel protected L929 cell from TNFα-induced cell death. - Highlights: • Collagen gel culture changed the morphology of L929 cells. • L929 cell cultured on collagen gel were resistant to TNFα-induced cell death. • Collagen gel culture inhibited TNFα-induced autophagy in L929 cells.

  2. Foldable and Cytocompatible Sol-gel TiO2 Photonics

    NASA Astrophysics Data System (ADS)

    Li, Lan; Zhang, Ping; Wang, Wei-Ming; Lin, Hongtao; Zerdoum, Aidan B.; Geiger, Sarah J.; Liu, Yangchen; Xiao, Nicholas; Zou, Yi; Ogbuu, Okechukwu; Du, Qingyang; Jia, Xinqiao; Li, Jingjing; Hu, Juejun

    2015-09-01

    Integrated photonics provides a miniaturized and potentially implantable platform to manipulate and enhance the interactions between light and biological molecules or tissues in in-vitro and in-vivo settings, and is thus being increasingly adopted in a wide cross-section of biomedical applications ranging from disease diagnosis to optogenetic neuromodulation. However, the mechanical rigidity of substrates traditionally used for photonic integration is fundamentally incompatible with soft biological tissues. Cytotoxicity of materials and chemicals used in photonic device processing imposes another constraint towards these biophotonic applications. Here we present thin film TiO2 as a viable material for biocompatible and flexible integrated photonics. Amorphous TiO2 films were deposited using a low temperature (<250 °C) sol-gel process fully compatible with monolithic integration on plastic substrates. High-index-contrast flexible optical waveguides and resonators were fabricated using the sol-gel TiO2 material, and resonator quality factors up to 20,000 were measured. Following a multi-neutral-axis mechanical design, these devices exhibit remarkable mechanical flexibility, and can sustain repeated folding without compromising their optical performance. Finally, we validated the low cytotoxicity of the sol-gel TiO2 devices through in-vitro cell culture tests. These results demonstrate the potential of sol-gel TiO2 as a promising material platform for novel biophotonic devices.

  3. Foldable and Cytocompatible Sol-gel TiO2 Photonics

    PubMed Central

    Li, Lan; Zhang, Ping; Wang, Wei-Ming; Lin, Hongtao; Zerdoum, Aidan B.; Geiger, Sarah J.; Liu, Yangchen; Xiao, Nicholas; Zou, Yi; Ogbuu, Okechukwu; Du, Qingyang; Jia, Xinqiao; Li, Jingjing; Hu, Juejun

    2015-01-01

    Integrated photonics provides a miniaturized and potentially implantable platform to manipulate and enhance the interactions between light and biological molecules or tissues in in-vitro and in-vivo settings, and is thus being increasingly adopted in a wide cross-section of biomedical applications ranging from disease diagnosis to optogenetic neuromodulation. However, the mechanical rigidity of substrates traditionally used for photonic integration is fundamentally incompatible with soft biological tissues. Cytotoxicity of materials and chemicals used in photonic device processing imposes another constraint towards these biophotonic applications. Here we present thin film TiO2 as a viable material for biocompatible and flexible integrated photonics. Amorphous TiO2 films were deposited using a low temperature (<250 °C) sol-gel process fully compatible with monolithic integration on plastic substrates. High-index-contrast flexible optical waveguides and resonators were fabricated using the sol-gel TiO2 material, and resonator quality factors up to 20,000 were measured. Following a multi-neutral-axis mechanical design, these devices exhibit remarkable mechanical flexibility, and can sustain repeated folding without compromising their optical performance. Finally, we validated the low cytotoxicity of the sol-gel TiO2 devices through in-vitro cell culture tests. These results demonstrate the potential of sol-gel TiO2 as a promising material platform for novel biophotonic devices. PMID:26344823

  4. Oral Traditions of Micronesians as an Index to Culture Change Reflected in Micronesian College Graduates. Final Report.

    ERIC Educational Resources Information Center

    Mitchell, Roger E.

    The study on which this final report is based focused on selected Micronesian students at the University of Guam who, after receiving their degrees, will return to their home islands to assume positions requiring them to function as intermediaries between the American and Micronesian approaches of life. Interviews with these students and with…

  5. Testosterone Nasal Gel

    MedlinePlus

    ... enough natural testosterone). Testosterone nasal gel is used only for men with low testosterone levels caused by ... is a controlled substance. Prescriptions may be refilled only a limited number of times; ask your pharmacist ...

  6. 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.

  7. Microfluidics with Gel Emulsions

    NASA Astrophysics Data System (ADS)

    Priest, Craig; Surenjav, Enkhtuul; Herminghaus, Stephan; Seemann, Ralf

    2006-03-01

    Microfluidic processing is usually achieved using single phase liquids. Instead, we use monodisperse emulsions to compartment liquids within microchannel geometries. At low continuous phase volume fractions, droplets self-organize to form well-defined arrangements, analogous to foam. While it is well-known that confined geometries can induce rearrangement of foam compartments at the millimeter-scale, similar dynamics are also expected for gel emulsions. We have studied online generation, organization and manipulation of gel emulsions using a variety of microchannel geometries. ``Passive'' reorganization, based on fixed channel geometries, can be supplemented by ``active'' manipulation by incorporating a ferrofluid phase. A ferromagnetic phase facilitates reorganization of liquid compartments on demand using an electromagnetic trigger. Moreover, coalescence between adjacent compartments within a gel emulsion can be induced using electrical potential. Microfluidics using gel emulsions will be well-suited for combinatorial chemistry, DNA sequencing, drug screening and protein crystallizations.

  8. Preparation of chitosan gel

    NASA Astrophysics Data System (ADS)

    Moussaoui, Y.; Mnasri, N.; Elaloui, E.; Ben Salem, R.; Lagerge, S.; de Menorval, L. C.

    2012-06-01

    Aerogel conditioning of the chitosan makes it possible to prepare porous solids of significant specific surface. The increase in the chitosan concentration or the degree of acetylation decreases the specific surface of the synthesized chitosan gel. Whereas drying with supercritical CO2 more effectively makes it possible to preserve the volume of the spheres of gel and to have a more significant specific surface in comparison with evaporative drying.

  9. Conformance Improvement Using Gels

    SciTech Connect

    Seright, Randall S.; Schrader, Richard; II Hagstrom, John; Wang, Ying; Al-Dahfeeri, Abdullah; Gary, Raven; Marin; Amaury; Lindquist, Brent

    2002-09-26

    This research project had two objectives. The first objective was to identify gel compositions and conditions that substantially reduce flow through fractures that allow direct channeling between wells, while leaving secondary fractures open so that high fluid injection and production rates can be maintained. The second objective was to optimize treatments in fractured production wells, where the gel must reduce permeability to water much more than that to oil.

  10. Crystallization from Gels

    NASA Astrophysics Data System (ADS)

    Narayana Kalkura, S.; Natarajan, Subramanian

    Among the various crystallization techniques, crystallization in gels has found wide applications in the fields of biomineralization and macromolecular crystallization in addition to crystallizing materials having nonlinear optical, ferroelectric, ferromagnetic, and other properties. Furthermore, by using this method it is possible to grow single crystals with very high perfection that are difficult to grow by other techniques. The gel method of crystallization provides an ideal technique to study crystal deposition diseases, which could lead to better understanding of their etiology. This chapter focuses on crystallization in gels of compounds that are responsible for crystal deposition diseases. The introduction is followed by a description of the various gels used, the mechanism of gelling, and the fascinating phenomenon of Liesegang ring formation, along with various gel growth techniques. The importance and scope of study on crystal deposition diseases and the need for crystal growth experiments using gel media are stressed. The various crystal deposition diseases, viz. (1) urolithiasis, (2) gout or arthritis, (3) cholelithiasis and atherosclerosis, and (4) pancreatitis and details regarding the constituents of the crystal deposits responsible for the pathological mineralization are discussed. Brief accounts of the theories of the formation of urinary stones and gallstones and the role of trace elements in urinary stone formation are also given. The crystallization in gels of (1) the urinary stone constituents, viz. calcium oxalate, calcium phosphates, uric acid, cystine, etc., (2) the constituents of the gallstones, viz. cholesterol, calcium carbonate, etc., (3) the major constituent of the pancreatic calculi, viz., calcium carbonate, and (4) cholic acid, a steroidal hormone are presented. The effect of various organic and inorganic ions, trace elements, and extracts from cereals, herbs, and fruits on the crystallization of major urinary stone and gallstone

  11. Level II Cultural Resource investigation for the Texoma Distribution Enhancements project, Cameron and Calcasieu Parishes, Louisiana: Final report

    SciTech Connect

    LeeDecker, C. H.; Holland, C. C.

    1987-10-01

    A Level II Cultural Resource Survey was completed for the Texoma Distribution Enhancements project, located in Cameron and Calcasieu Parishes, Louisiana. The 13-mile pipeline extends from Strategic Petroleum Reserve No. 3 to a terminus near Vincent Landing. Located in Louisiana's southwest coastal zone, the pipeline will traverse extensive marsh lands as well as upland prairie terrace areas. Present land use within the project area consists primarily of undeveloped marsh land and cattle range. The study methods included background research, intensive pedestrian survey with systematic shovel testing, a boat survey, and laboratory analysis of recovered artifact collections. One historic site, 16CU205, was identified during the field survey, and it was tested for National Register eligibility. The site is assignable to the Industrialization and Modernization (1890-1940) Cultural Unit. Archaeological testing indicates that it is a rural residence or farmstead, with a house and one outbuilding within the proposed right-of-way. The site lacks significant historical association and sufficient archaeological integrity to merit inclusion on the National Register of Historic Places. Four standing structures were also identified during the field survey. The structures are agricultural outbuildings, less than 40 years in age, that possess no architectural distinction or historical association. They have been documented photographically and by scaled plan drawings, but do not merit additional study prior to their destruction. 24 refs., 15 figs., 3 tabs.

  12. Polyacrylamide gel electrophoresis.

    PubMed

    Chrambach, A; Rodbard, D

    1971-04-30

    Polyacrylamide gel electrophoresis (PAGE) provides a versatile, gentle, high resolution method for fractionation and physical-chemical characterization of molecules on the basis of size, conformation, and net charge. The polymerization reaction can be rigorously controlled to provide uniform gels of reproducible, measurable pore size over a wide range. This makes it possible to obtain reproducible relative mobility (Rf) values as physical-chemical constants. Application and extension of Ogston's (random fiber) model for a gel allows for calculation of molecular volume, surface area, or radius, free mobility, and valence from RJ measurements at several gel concentrations, to calculate gel concentration for optimal resolution, and to predict behavior of macromolecules on gel gradients by computerized methods. Extension of classical moving boundary theory has been used to generate multiphasic buffer systems (providing selective stacking, unstacking, restacking, and preparative steady-state-stacking) with known operating characteristics for any pH at 0 degrees and 25 degrees C. A general strategy for isolation of macromolecules and for macromolecular mapping has been developed. Preparative scale PAGE is operational for milligram loads and feasible for gram quantities. PMID:4927678

  13. Gastric culture

    MedlinePlus

    ... test or procedure preparation (3 to 6 years) School age test or procedure preparation (6 to 12 ... immune system. The final results of the gastric culture test may take several weeks. Your provider will ...

  14. CONFORMANCE IMPROVEMENT USING GELS

    SciTech Connect

    Randall S. Seright

    2002-02-28

    This technical progress report describes work performed from June 20 through December 19, 2001, for the project, ''Conformance Improvement Using Gels''. Interest has increased in some new polymeric products that purport to substantially reduce permeability to water while causing minimum permeability reduction to oil. In view of this interest, we are currently studying BJ's Aqua Con. Results from six corefloods revealed that the Aqua Con gelant consistently reduced permeability to water more than that to oil. However, the magnitude of the disproportionate permeability reduction varied significantly for the various experiments. Thus, as with most materials tested to date, the issue of reproducibility and control of the disproportionate permeability remains to be resolved. Concern exists about the ability of gels to resist washout after placement in fractures. We examined whether a width constriction in the middle of a fracture would cause different gel washout behavior upstream versus downstream of the constriction. Tests were performed using a formed Cr(III)-acetate-HPAM gel in a 48-in.-long fracture with three sections of equal length, but with widths of 0.08-, 0.02-, and 0.08-in., respectively. The pressure gradients during gel extrusion (i.e., placement) were similar in the two 0.08-in.-wide fracture sections, even though they were separated by a 0.02-in.-wide fracture section. The constriction associated with the middle fracture section may have inhibited gel washout during the first pulse of brine injection after gel placement. However, during subsequent phases of brine injection, the constriction did not inhibit washout in the upstream fracture section any more than in the downstream section.

  15. Genipin-crosslinked chitosan/poly-L-lysine gels promote fibroblast adhesion and proliferation.

    PubMed

    Mekhail, Mina; Jahan, Kaushar; Tabrizian, Maryam

    2014-08-01

    Chitosan blends have been widely investigated to create biomaterials with desirable physicochemical and biological properties for tissue engineering applications. A recurring difficulty, however, has been to maintain their stability in an aqueous environment. The rationale behind this study was to demonstrate that genipin crosslinking can improve and maintain the stability of chitosan/poly-l-lysine (PLL) blends. Four gel formulations were prepared by varying the weight ratios of chitosan and PLL. Electron microscopy revealed that genipin crosslinking provided a more homogenous gel surface compared to uncrosslinked gels. Moreover, it was discovered that 3h was sufficient to stabilize the gels. In vitro studies using fibroblasts demonstrated that genipin-crosslinked gels enhanced fibroblasts' attachment as compared to uncrosslinked gels. Moreover, cell viability was significantly improved by 1.6 times on 60:40 gels, and 6.5 times on 50:50 gels after crosslinking. Finally, proliferation was enhanced up to 5 times on 60:40 gels. PMID:24751251

  16. Cultural and management practices for the Chinese tallow tree as a biomass fuel source: Final report, 1978-1984

    SciTech Connect

    Cowles, J.R.; Scheld, H.W.

    1987-12-01

    The growth and cultural conditions of the Chinese tallow tree, Sapium sebiferum (L.) Roxb., were studied over a 6-year period. Plots from seeds or seedlings at designated densities and plots established in natural stands were studied. The maximum growth rate of the Chinese tallow tree in a marginal soil near the Texas gulf coast was 10 to 15 dry tons/hectare/year. The young trees were able to withstand long periods of flooding as well as extended dry periods. The tree species also is resistant to diseases and pathogens. The Chinese tallow tree is particularly adaptable to close spacing, direct seeding, coppicing, and short-rotation growth cycles. These factors all favor the economic usefulness of the tree as a bioenergy species. In addition, the tallow tree is economically valuable in honey production and as a chemical feedstock. Fertilization is important during the early phases of stand establishment but has diminished usefulness in subsequent years. The Chinese tallow tree appears to be an excellent bioenergy species in the southern coastal areas of the United States and especially in marginal soils. The Chinese tallow tree has the potential of producing 15 to 20 tons/hectare annually by coppicing on a 5- to 8-year rotation at close spacings. 12 figs., 12 tabs.

  17. Engineering 3D Cellularized Collagen Gels for Vascular Tissue Regeneration.

    PubMed

    Meghezi, Sébastien; Seifu, Dawit G; Bono, Nina; Unsworth, Larry; Mequanint, Kibret; Mantovani, Diego

    2015-01-01

    Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. Collagen has been extensively used for a wide range of biomedical applications and is considered a valid alternative to synthetic materials due to its inherent biocompatibility (i.e., low antigenicity, inflammation, and cytotoxic responses). However, the limited mechanical properties and the related low hand-ability of collagen gels have hampered their use as scaffold materials for vascular tissue engineering. Therefore, the rationale behind this work was first to engineer cellularized collagen gels into a tubular-shaped geometry and second to enhance smooth muscle cells driven reorganization of collagen matrix to obtain tissues stiff enough to be handled. The strategy described here is based on the direct assembling of collagen and smooth muscle cells (construct) in a 3D cylindrical geometry with the use of a molding technique. This process requires a maturation period, during which the constructs are cultured in a bioreactor under static conditions (without applied external dynamic mechanical constraints) for 1 or 2 weeks. The "static bioreactor" provides a monitored and controlled sterile environment (pH, temperature, gas exchange, nutrient supply and waste removal) to the constructs. During culture period, thickness measurements were performed to evaluate the cells-driven remodeling of the collagen matrix, and glucose consumption and lactate production rates were measured to monitor the cells metabolic activity. Finally, mechanical and viscoelastic properties were assessed for the resulting tubular constructs. To this end, specific protocols and a focused know-how (manipulation, gripping, working in hydrated environment, and so on) were developed to characterize the engineered tissues. PMID:26132527

  18. Engineering 3D Cellularized Collagen Gels for Vascular Tissue Regeneration

    PubMed Central

    Meghezi, Sébastien; Seifu, Dawit G.; Bono, Nina; Unsworth, Larry; Mequanint, Kibret; Mantovani, Diego

    2015-01-01

    Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. Collagen has been extensively used for a wide range of biomedical applications and is considered a valid alternative to synthetic materials due to its inherent biocompatibility (i.e., low antigenicity, inflammation, and cytotoxic responses). However, the limited mechanical properties and the related low hand-ability of collagen gels have hampered their use as scaffold materials for vascular tissue engineering. Therefore, the rationale behind this work was first to engineer cellularized collagen gels into a tubular-shaped geometry and second to enhance smooth muscle cells driven reorganization of collagen matrix to obtain tissues stiff enough to be handled. The strategy described here is based on the direct assembling of collagen and smooth muscle cells (construct) in a 3D cylindrical geometry with the use of a molding technique. This process requires a maturation period, during which the constructs are cultured in a bioreactor under static conditions (without applied external dynamic mechanical constraints) for 1 or 2 weeks. The “static bioreactor” provides a monitored and controlled sterile environment (pH, temperature, gas exchange, nutrient supply and waste removal) to the constructs. During culture period, thickness measurements were performed to evaluate the cells-driven remodeling of the collagen matrix, and glucose consumption and lactate production rates were measured to monitor the cells metabolic activity. Finally, mechanical and viscoelastic properties were assessed for the resulting tubular constructs. To this end, specific protocols and a focused know-how (manipulation, gripping, working in hydrated environment, and so on) were developed to characterize the engineered tissues. PMID:26132527

  19. Continuum Models of Stimuli-responsive Gels

    NASA Astrophysics Data System (ADS)

    Hong, Wei

    Immersed in a solution of small molecules and ions, a network of long-chain polymers may imbibe the solution and swell, resulting in a polymeric gel. Depending on the molecular structure of the polymers, the amount of swelling can be regulated by moisture, mechanical forces, ionic strength, electric field, pH value, and many other types of stimuli. Starting from the basic principles of non-equilibrium thermodynamics, this chapter formulates a field theory of the coupled large deformation and mass transportation in a neutral polymeric gel. The theory is then extended to study polyelectrolyte gels with charge-carrying networks by accounting for the electromechanical coupling and migration of solute ions. While the theoretical framework is adaptable to various types of material models, some representative ones are described through specific free-energy functions and kinetic laws. A specific material law for pH-sensitive gels—a special type of polyelectrolyte gels—is introduced as an example of incorporating chemical reactions in modeling stimuli-responsive gels. Finally, a simplified theory for the equilibrium but inhomogeneous swelling of a polymeric gel is deduced. The theory and the specific material models are illustrated through several examples.

  20. Cultural History and Cultural Materialism.

    ERIC Educational Resources Information Center

    Berman, Ronald

    1990-01-01

    Historicism critiques cultural history and cultural materialism as a methodology for literary analysis. Questions the finality of interpretation, how original values change, and whether dramatic history implies actual history. Using Shakespearean plays, analyzes the power and politics of a play in relation to its audience; posits that cultural…

  1. Swelling of Olympic Gels

    NASA Astrophysics Data System (ADS)

    Lang, M.; Fischer, J.; Werner, M.; Sommer, J.-U.

    2014-06-01

    The swelling equilibrium of Olympic gels, which are composed of entangled cyclic polymers, is studied by Monte Carlo simulations. In contrast to chemically cross-linked polymer networks, we observe that Olympic gels made of chains with a larger degree of polymerization, N, exhibit a smaller equilibrium swelling degree, Q∝N-0.28ϕ0-0.72, at the same polymer volume fraction ϕ0 at network preparation. This observation is explained by a desinterspersion (reorganization with release of nontrapped entanglements) process of overlapping nonconcatenated rings upon swelling.

  2. Droplet Spreading with Sol-Gel Transition

    NASA Astrophysics Data System (ADS)

    Jalaal, Maziyar; Stoeber, Boris; Balmforth, Neil J.

    2014-11-01

    The impact and spreading of liquid droplets on a smooth solid substrate is a classical subject with several industrial applications such as ink-jet printing, spray cooling, coating, and many others. For many of these deposition processes, controlling the final shape of the drop is critical. In the current research, a new technique for controlling the spreading of droplets impacting a substrate is presented. This technique exploits the rheology of a thermo-responsive polymer solution that undergoes a reversible sol/gel transition above a critical temperature. Experiments are conducted using a combination of shadowgraphy and micro-PIV to observe spreading drops. It is shown that the final diameter of a droplet can be controlled through the temperature of the substrate and the tunable sol/gel transition temperature of the fluid.A mathematical model is provided to further elucidate the flow dynamics.

  3. Rheology of Active Gels

    NASA Astrophysics Data System (ADS)

    Chen, Daniel

    2015-03-01

    Active networks drive a diverse range of critical processes ranging from motility to division in living cells, yet a full picture of their rheological capabilities in non-cellular contexts is still emerging, e.g., How does the rheological response of a network capable of remodeling under internally-generated stresses differ from that of a passive biopolymer network? In order to address this and other basic questions, we have engineered an active gel composed of microtubules, bidirectional kinesin motors, and molecular depletant that self-organizes into a highly dynamic network of active bundles. The network continually remodels itself under ATP-tunable cycles of extension, buckling, fracturing, and self-healing. Using confocal rheometry we have simultaneously characterized the network's linear and non-linear rheological responses to shear deformation along with its dynamic morphology. We find several surprising and unique material properties for these active gels; most notably, rheological cloaking, the ability of the active gel to drive large-scale fluid mixing over several orders of flow magnitude while maintaining an invariant, solid-like rheological profile and spontaneous flow under confinement, the ability to exert micro-Newton forces to drive persistent directed motion of the rheometer tool. Taken together, these results and others to be discussed highlight the rich stress-structure-dynamics relationships in this class of biologically-derived active gels.

  4. High Resolution Quantitative Proteomics of HeLa Cells Protein Species Using Stable Isotope Labeling with Amino Acids in Cell Culture(SILAC), Two-Dimensional Gel Electrophoresis(2DE) and Nano-Liquid Chromatograpohy Coupled to an LTQ-OrbitrapMass Spectrometer*

    PubMed Central

    Thiede, Bernd; Koehler, Christian J.; Strozynski, Margarita; Treumann, Achim; Stein, Robert; Zimny-Arndt, Ursula; Schmid, Monika; Jungblut, Peter R.

    2013-01-01

    The proteomics field has shifted over recent years from two-dimensional gel electrophoresis (2-DE)-based approaches to SDS-PAGE or gel-free workflows because of the tremendous developments in isotopic labeling techniques, nano-liquid chromatography, and high-resolution mass spectrometry. However, 2-DE still offers the highest resolution in protein separation. Therefore, we combined stable isotope labeling with amino acids in cell culture of controls and apoptotic HeLa cells with 2-DE and the subsequent analysis of tryptic peptides via nano-liquid chromatography coupled to an LTQ-Orbitrap mass spectrometer to obtain quantitative data using the methods with the highest resolving power on all levels of the proteomics workflow. More than 1,200 proteins with more than 2,700 protein species were identified and quantified from 816 Coomassie Brilliant Blue G-250 stained 2-DE spots. About half of the proteins were identified and quantified only in single 2-DE spots. The majority of spots revealed one to five proteins; however, in one 2-DE spot, up to 23 proteins were identified. Only half of the 2-DE spots represented a dominant protein with more than 90% of the whole protein amount. Consequently, quantification based on staining intensities in 2-DE gels would in approximately half of the spots be imprecise, and minor components could not be quantified. These problems are circumvented by quantification using stable isotope labeling with amino acids in cell culture. Despite challenges, as shown in detail for lamin A/C and vimentin, the quantitative changes of protein species can be detected. The combination of 2-DE with high-resolution nano-liquid chromatography-mass spectrometry allowed us to identify proteomic changes in apoptotic cells that would be unobservable using any of the other previously employed proteomic workflows. PMID:23033477

  5. Foam and gel methods for the decontamination of metallic surfaces

    DOEpatents

    Nunez, Luis; Kaminski, Michael Donald

    2007-01-23

    Decontamination of nuclear facilities is necessary to reduce the radiation field during normal operations and decommissioning of complex equipment. In this invention, we discuss gel and foam based diphosphonic acid (HEDPA) chemical solutions that are unique in that these solutions can be applied at room temperature; provide protection to the base metal for continued applications of the equipment; and reduce the final waste form production to one step. The HEDPA gels and foams are formulated with benign chemicals, including various solvents, such as ionic liquids and reducing and complexing agents such as hydroxamic acids, and formaldehyde sulfoxylate. Gel and foam based HEDPA processes allow for decontamination of difficult to reach surfaces that are unmanageable with traditional aqueous process methods. Also, the gel and foam components are optimized to maximize the dissolution rate and assist in the chemical transformation of the gel and foam to a stable waste form.

  6. Cell viability in a wet silica gel.

    PubMed

    Nieto, Alejandra; Areva, Sami; Wilson, Timothy; Viitala, Reeta; Vallet-Regi, Maria

    2009-11-01

    A modified two-step sol-gel route using silicon ethoxide (TEOS) has been used to synthesize amorphous sol-gel-derived silica, which has been successfully used as a cell encapsulation matrix for 3T3 mouse fibroblasts and CRL-2595 epithelial cells due to its non-toxicity. The sol-gel procedure comprised a first, low pH hydrolysis step, followed by a neutral condensation-gelation step. A high water-to-TEOS ratio and the addition of d-glucose as a porogen and source of nutrients were chosen to minimize silica dissolution and improve the biocompatibility of the process. Indeed, the cell integrity in the encapsulation process was preserved by alcohol removal from the starting solution. Cells were then added in a buffered medium, causing rapid gelation and entrapment of the cells within a randomly structured siloxane matrix in the shape of a monolith, which was maintained in the wet state. MTT and alamarBlue assays were used to check the cytotoxicity of the silica gels and the viability of entrapped cells at initial times in contact with silica. To improve cell attachment, cell clumping experiments - where groups of cells were formed - were designed, rendering improved viability. The obtained materials are therefore excellent candidates for designing tissue-culture scaffolds and implantable bioreactors for biomedical applications. PMID:19481618

  7. [Adhesion of Bacillus subtilis on the surface of pectin-calcium gel].

    PubMed

    Gunter, E A; Melekhin, A K

    2015-01-01

    Pectin-calcium gels obtained based on pectins of callus cultures are able to adhere to the surface of cells of Gram-positive bacteria Bacillus subtilis to various degrees and this is thanks to the structural features of pectin. Rapid adhesion of the cells to gels obtained from the pectin of Tanacetum vulgare (TVC) callus cultures is associated with a high content of the linear region in the carbohydrate chain of pectin, a high molecular weight, and a low degree of methyl etherification of pectin. The number of adherent cells on the surface of gels obtained from pectins of Silene vulgaris callus cultures (SVC), TVC, and Lemna minor (LMC) after 8 h of incubation was close, whereas the number of cells was minimal on a gel produced using the pectin of Silene tatarica (STC) callus culture. This was due to the higher degree of methyl etherification of STC pectin (45%) compared to other pectins (4-12%). The adhesion rate constant (k) of B. subtilis for TCV gel during the first 120 min was the highest in comparison with other gels; the k value for SVC, STC and LMC gels was similar. The lowest level of k was characteristic for the gel from commercial apple pectin. The obtained data can beused for the production of gels with adhesive and antiadhesive properties. PMID:25842905

  8. Yielding of colloidal gels under steady and oscillatory shear

    NASA Astrophysics Data System (ADS)

    Petekidis, George; Moghimi, Esmaeel; Koumakis, Nick; Forth Team

    2015-03-01

    The structural and rheological properties of intermediate volume fraction colloid polymer gels are examined during and after steady and oscillatory shear flow using rheometry, confocal microscopy, light scattering and Brownian Dynamics simulations. Our main objective is to rationalize the microscopic mechanisms through which one can tune the mechanical properties of such metastable colloidal gels by imposing different types of external shear and flow. Experimentally, the gels consist of model hard sphere particle dispersions of φ = 0.44 with the addition of non-adsorbing linear chains, while BD simulations are conducted for hard spheres with the superposition of an AO potential for depletion attractions. Structural analysis shows that variation of the applied shear rate produces strong changes in the structure of the gels both when under shear and during gel reformation at cessation. Larger rates are characterized by disperse particles and the total breakage of structures at rest, which after cessation evolve with time into strong solids with relatively homogeneous structures. However, smaller rates show large inhomogeneous structures under flow, which do not evolve after cessation and additionally exhibit reduced elasticity and as such are weaker solids. Furthermore oscillatory shear is far more efficient than steady shear creating gels with stronger differences in their elastic modulus. Thus by tuning the way a gel is sheared, one may vary the final strength and structure of the resulting gel. Work in collaboration with R. Besseling, W. C. K. Poon and J. F. Brady

  9. Electrodeposited gels prepared from protein alloys

    PubMed Central

    Lin, Yinan; Wang, Siran; Chen, Ying; Wang, Qianrui; Burke, Kelly A; Spedden, Elise M; Staii, Cristian; Weiss, Anthony S; Kaplan, David L

    2015-01-01

    Aim Silk-tropoelastin alloys, composed of recombinant human tropoelastin and regenerated Bombyx mori silk fibroin, are an emerging, versatile class of biomaterials endowed with tunable combinations of physical and biological properties. Electrodeposition of these alloys provides a programmable means to assemble functional gels with both spatial and temporal controllability. Materials & methods Tropoelastin-modified silk was prepared by enzymatic coupling between tyrosine residues. Hydrogel coatings were electrodeposited using two wire electrodes. Results & discussion Mechanical characterization and in vitro cell culture revealed enhanced adhesive capability and cellular response of these alloy gels as compared with electrogelled silk alone. Conclusion These electro-depositable silk-tropoelastin alloys constitute a suitable coating material for nanoparticle-based drug carriers and offer a novel opportunity for on-demand encapsulation/release of nanomedicine. PMID:25816881

  10. Attitudes Toward Indian Culture and Its Incorporation in the School Curriculum: Students, Parents, Teachers, and Community Leaders; Perceptions of Indian Education. The National Study of American Indian Education, Series IV, No. 10, Final Report.

    ERIC Educational Resources Information Center

    Birchard, Bruce A.

    As a part of the Final Report of the National Study of American Indian Education, this document reported on the perceptions and attitudes of Indian students, parents, teachers, and community leaders toward Indian culture and its incorporation in the school curriculum in their respective communities. Attitudes were ascertained using various scales.…

  11. Carcinogenesis studies with benzoyl peroxide (Panoxyl gel 5%)

    SciTech Connect

    Iversen, O.H.

    1986-04-01

    Several groups of hairless mice were given UV radiation with and without pretreatment with 7,12-dimethylbenz(a)anthracene (DMBA), 5% benzoyl peroxide in a gel (Panoxyl), and gel alone, in various combinations, with appropriate control groups included, in order to see whether benzoyl peroxide, which is known to enhance chemical skin carcinogenesis after a single, small dose of DMBA, also enhances UV carcinogenesis. The mice were observed for skin tumors, and all skin lesions were histologically investigated. The percentage of tumor-bearing animals with time is called the tumor rate, the total number of tumors occurring is called the tumor yield. Continual treatment with 5% benzoyl peroxide in gel twice a week, with or without a short pretreatment period of UV radiation resulted in only 2 skin carcinomas, which is remarkable, but not significant. Both Panoxyl and gel alone enhanced tumorigenicity significantly in animals pretreated with a single dose of 51.2 micrograms DMBA. There was no difference between the enhancement caused by Panoxyl and the gel as regards the tumor rate, but when measured as final tumor yield, Panoxyl was slightly more tumor-enhancing than gel alone. However, both Panoxyl and gel protected significantly against UV tumorigenesis (all tumors). There was no difference between the protective effect of the 2 types of treatment. Neither Panoxyl nor gel alone influenced significantly UV skin carcinogenesis (malignant tumors). It is concluded that under these experimental conditions both Panoxyl and gel alone tend to protect against the tumorigenicity and do not enhance the carcinogenicity of UV radiation in hairless mice, whereas both gel and Panoxyl enhance chemical carcinogenesis. The carcinogenic mechanisms may be different for UV and chemical carcinogenesis, respectively.

  12. Clarification Procedure for Gels

    NASA Technical Reports Server (NTRS)

    Barber, Patrick G.; Simpson, Norman R.

    1987-01-01

    Procedure developed to obtain transparent gels with consistencies suitable for crystal growth, by replacing sodium ions in silicate solution with potassium ions. Clarification process uses cation-exchange resin to replace sodium ions in stock solution with potassium ions, placed in 1M solution of soluble potassium salt. Slurry stirred for several hours to allow potassium ions to replace all other cations on resin. Supernatant solution decanted through filter, and beads rinsed with distilled water. Rinsing removes excess salt but leaves cation-exchange beads fully charged with potassium ions.

  13. Phase 1 Randomized Trial of the Vaginal Safety and Acceptability of SPL7013 Gel (VivaGel®) in Sexually Active Young Women (MTN-004)

    PubMed Central

    MCGOWAN, Ian; GOMEZ, Kailazarid; BRUDER, Karen; FEBO, Irma; CHEN, Beatrice A; RICHARDSON, Barbra A; HUSNIK, Marla; LIVANT, Edward; PRICE, Clare; Jacobson, Cindy

    2011-01-01

    Objectives The study was designed to assess the safety, adherence, acceptability, and effect on vaginal microflora of 3% SPL7013 Gel (VivaGel®), a novel dendrimer topical microbicide that inhibits HIV, HSV-2 and HPV in vitro and in animal models. Design Phase 1, randomized, double-blind, placebo-controlled study in sexually active women. Methods Sixty-one sexually active women aged 18–24 years were recruited from three sites in the United States. Participants were randomized 1:1:1 to receive VivaGel, VivaGel placebo, or a hydroxyethylcellulose (HEC) placebo twice daily for 14 consecutive days. Safety endpoints included genitourinary and/or other adverse events (AE). Changes in vaginal flora were determined from Gram-stained vaginal smears and quantitative vaginal culture. Results No serious AEs or withdrawals due to AEs were reported. Genitourinary symptoms were reported as follows: VivaGel (n=17/22; 77.3%), VivaGel placebo (n=14/21; 66.7%) and HEC (n=8/18; 44.4%) (NS, p=0.1). The incidence of abnormal pelvic exam findings was similar across all gel arms of the study. Using pair-wise comparison, women in the VivaGel arm had a significantly higher incidence of related genitourinary AEs compared with women in the HEC gel arm (0.297 versus 0.111 per 100 person years, respectively; p=0.003). Exposure to VivaGel and VivaGel placebo resulted in minor shifts in the vaginal microflora but there was no overall impact on incidence of bacterial vaginosis as assessed by Nugent score. Conclusions VivaGel was generally well tolerated and comparable with the VivaGel placebo, although there was a higher incidence of low grade related genital AEs compared to the HEC placebo gel. PMID:21505316

  14. Disulfide-Functionalized Diblock Copolymer Worm Gels.

    PubMed

    Warren, Nicholas J; Rosselgong, Julien; Madsen, Jeppe; Armes, Steven P

    2015-08-10

    Two strategies for introducing disulfide groups at the outer surface of RAFT-synthesized poly(glycerol monomethacrylate)-poly(2-hydroxypropyl methacrylate) (PGMA-PHPMA, or Gx-Hy for brevity) diblock copolymer worms are investigated. The first approach involved statistical copolymerization of GMA with a small amount of disulfide dimethacrylate (DSDMA, or D) comonomer to afford a G54-D0.50 macromolecular chain transfer agent (macro-CTA); this synthesis was conducted in relatively dilute solution in order to ensure mainly intramolecular cyclization and hence the formation of linear chains. Alternatively, a new disulfide-based bifunctional RAFT agent (DSDB) was used to prepare a G45-S-S-G45 (or (G45-S)2) macro-CTA. A binary mixture of a non-functionalized G55 macro-CTA was utilized with each of these two disulfide-based macro-CTAs in turn for the RAFT aqueous dispersion polymerization of 2-hydroxypropyl methacrylate (HPMA). By targeting a PHPMA DP of 130 and systematically varying the molar ratio of the two macro-CTAs, a series of disulfide-functionalized diblock copolymer worm gels were obtained. For both formulations, oscillatory rheology studies confirmed that higher disulfide contents led to stronger gels, presumably as a result of inter-worm covalent bond formation via disulfide/thiol exchange. Using the DSDB-based macro-CTA led to the strongest worm gels, and this formulation also proved to be more effective in suppressing the thermosensitive behavior that is observed for the nondisulfide-functionalized control worm gel. However, macroscopic precipitation occurred when the proportion of DSDB-based macro-CTA was increased to 50 mol %, whereas the DSDMA-based macro-CTA could be utilized at up to 80 mol %. Finally, the worm gel modulus could be reduced to that of a nondisulfide-containing worm gel by reductive cleavage of the inter-worm disulfide bonds using excess tris(2-carboxyethyl)phosphine (TCEP) to yield thiol groups. These new biomimetic worm gels are

  15. High transparent shape memory gel

    NASA Astrophysics Data System (ADS)

    Gong, Jin; Arai, Masanori; Kabir, M. H.; Makino, Masato; Furukawa, Hidemitsu

    2014-03-01

    Gels are a new material having three-dimensional network structures of macromolecules. They possess excellent properties as swellability, high permeability and biocompatibility, and have been applied in various fields of daily life, food, medicine, architecture, and chemistry. In this study, we tried to prepare new multi-functional and high-strength gels by using Meso-Decoration (Meso-Deco), one new method of structure design at intermediate mesoscale. High-performance rigid-rod aromatic polymorphic crystals, and the functional groups of thermoreversible Diels-Alder reaction were introduced into soft gels as crosslinkable pendent chains. The functionalization and strengthening of gels can be realized by meso-decorating the gels' structure using high-performance polymorphic crystals and thermoreversible pendent chains. New gels with good mechanical properties, novel optical properties and thermal properties are expected to be developed.

  16. Foam and gel decontamination techniques

    SciTech Connect

    McGlynn, J.F.; Rankin, W.N.

    1989-01-01

    The Savannah River Site is investigating decontamination technology to improve current decontamination techniques, and thereby reduce radiation exposure to plant personnel, reduce uptake of radioactive material, and improve safety during decontamination and decommissioning activities. When decontamination chemicals are applied as foam and gels, the contact time and cleaning ability of the chemical increases. Foam and gel applicators apply foam or gel that adheres to the surface being decontaminated for periods ranging from fifteen minutes (foam) to infinite contact (gel). This equipment was started up in a cold environment. The desired foam and gel consistency was achieved, operators were trained in its proper maintenance and operation, and the foam and gel were applied to walls, ceilings, and hard to reach surfaces. 17 figs.

  17. Polyoxometalate-based Supramolecular Gel

    NASA Astrophysics Data System (ADS)

    He, Peilei; Xu, Biao; Liu, Huiling; He, Su; Saleem, Faisal; Wang, Xun

    2013-05-01

    Self-assemblyings of surfactant-encapsulated Wells-Dawson polyoxometalates (SEPs) nanobuilding blocks in butanone and esters yielded supramolecular gels showing thermo and photo responsive properties. The gels can be further polymerized if unsaturated esters were used and subsequently electrospinned into nanowires and non-woven mats. The as-prepared non-woven mats have a Young's modulus as high as 542.55 MPa. It is believed that this supramolecular gel is a good platform for polyoxometalates processing.

  18. Thermally reversible xyloglucan gels as vehicles for nasal drug delivery.

    PubMed

    Mahajan, Hitendra S; Tyagi, Vinod; Lohiya, Gopal; Nerkar, Pankaj

    2012-01-01

    The aim of this study was to investigate the potential application of thermosensitive gels formed by a xyloglucan polysaccharide derived from tamarind seed for nasal drug delivery. Xyloglucan that had been partially degraded by β-galactosidase to eliminate 45% of galactose residues formed gels at concentrations of 2.5% w/w at gelation temperatures decreasing over the range 27-28°C. The in vitro release of ondansetron hydrochloride from the enzyme-degraded xyloglucan gels followed higuchi kinetics over a period of 5 h at 34°C by anomalous transport mechanism. The ex vivo permeation of ondansetron hydrochloride from the gels was sustained. Histological examination of nasal mucosa following a single administration of the gels showed no evidence of mucosal damage. Finally, the bioavailability study in rabbits revealed that the absolute bioavailability of ondansetron hydrochloride was significantly increased from 28.64% in the case of the oral drug solution to 52.79% in the case of the nasal in situ gel. The results of this study suggest the potential of the enzyme-degraded xyloglucan gels as vehicles for nasal delivery of drugs. PMID:22823894

  19. Electrically controlled polymeric gel actuators

    DOEpatents

    Adolf, Douglas B.; Shahinpoor, Mohsen; Segalman, Daniel J.; Witkowski, Walter R.

    1993-01-01

    Electrically controlled polymeric gel actuators or synthetic muscles capable of undergoing substantial expansion and contraction when subjected to changing pH environments, temperature, or solvent. The actuators employ compliant containers for the gels and their solvents. The gels employed may be cylindrical electromechanical gel fibers such as polyacrylamide fibers or a mixture of poly vinyl alcohol-polyacrylic acid arranged in a parallel aggregate and contained in an electrolytic solvent bath such as salt water. The invention includes smart, electrically activated devices exploiting this phenomenon. These devices are capable of being manipulated via active computer control as large displacement actuators for use in adaptive structure such as robots.

  20. Electrically controlled polymeric gel actuators

    DOEpatents

    Adolf, D.B.; Shahinpoor, M.; Segalman, D.J.; Witkowski, W.R.

    1993-10-05

    Electrically controlled polymeric gel actuators or synthetic muscles are described capable of undergoing substantial expansion and contraction when subjected to changing pH environments, temperature, or solvent. The actuators employ compliant containers for the gels and their solvents. The gels employed may be cylindrical electromechanical gel fibers such as polyacrylamide fibers or a mixture of poly vinyl alcohol-polyacrylic acid arranged in a parallel aggregate and contained in an electrolytic solvent bath such as salt water. The invention includes smart, electrically activated devices exploiting this phenomenon. These devices are capable of being manipulated via active computer control as large displacement actuators for use in adaptive structure such as robots. 11 figures.

  1. Gel polymer electrolytes for batteries

    DOEpatents

    Balsara, Nitash Pervez; Eitouni, Hany Basam; Gur, Ilan; Singh, Mohit; Hudson, William

    2014-11-18

    Nanostructured gel polymer electrolytes that have both high ionic conductivity and high mechanical strength are disclosed. The electrolytes have at least two domains--one domain contains an ionically-conductive gel polymer and the other domain contains a rigid polymer that provides structure for the electrolyte. The domains are formed by block copolymers. The first block provides a polymer matrix that may or may not be conductive on by itself, but that can soak up a liquid electrolyte, thereby making a gel. An exemplary nanostructured gel polymer electrolyte has an ionic conductivity of at least 1.times.10.sup.-4 S cm.sup.-1 at 25.degree. C.

  2. Colloidal thermoresponsive gel forming hybrids.

    PubMed

    Liu, Ruixue; Tirelli, Nicola; Cellesi, Francesco; Saunders, Brian R

    2010-09-15

    Colloidal hybrids comprise organic and inorganic components and are attracting considerable attention in the literature. Recently, we reported hybrid anisotropic microsheets that formed thermoresponsive gels in polymer solutions [Liu et al., Langmuir, 25, 490, 2009]. Here, we investigate the composition and properties of these hybrid colloids themselves in detail for the first time. Three different cationic PNIPAm (N-isopropylacrylamide) graft copolymers and two inorganic nanoparticle types (laponite and Ludox silica) were used to prepare a range of hybrids. Anisotropic microsheets only formed when laponite particles were added to the copolymer implying directed self-assembly. Aqueous dispersions of the microsheets spontaneously formed gels at room temperature and these gels were thermoresponsive. They represent a new class of gel forming colloid and are termed thermoresponsive gel forming hybrids. The compositions of the hybrids were determined from thermogravimetric analysis and those that gave gel forming behaviour identified. Variable-temperature rheology experiments showed that the elasticity of the gels increased linearly with temperature. The reversibility of the thermally-triggered changes in gel elasticity was investigated. The concentration dependence of the rheology data was well described by elastic percolation scaling theory and the data could be collapsed onto a master curve. The concentration exponent for the elastic modulus was 2.5. The strong attractive interactions that exist between the dispersed gel forming hybrids was demonstrated by the formation of stable thermoresponsive hybrid hydrogels through casting of hybrid dispersions. PMID:20561633

  3. Fibrillar peptide gels in biotechnology and biomedicine

    PubMed Central

    Jung, Jangwook P.; Gasiorowski, Joshua Z.; Collier, Joel H.

    2012-01-01

    Peptides, peptidomimetics, and peptide derivatives that self-assemble into fibrillar gels have received increasing interest as synthetic extracellular matrices for applications in 3D cell culture and regenerative medicine. Recently, several of these fibrillizing molecules have been functionalized with bioactive components such as cell-binding ligands, degradable sequences, drug-eluting compounds, and chemical modifications for cross-linking, producing gels that can reliably display multiple factors simultaneously. This capacity for incorporating precise levels of many different biological and chemical factors is advantageous given the natural complexity of cell-matrix interactions that many current biomaterial strategies seek to mimic. In this review, recent efforts in the area of fibril-forming peptide materials are described, and advantages of biomaterials containing multiple modular elements are outlined. In addition, a few hurdles and open questions surrounding fibrillar peptide gels are discussed, including issues of the materials’ structural heterogeneity, challenges in fully characterizing the diversity of their self-assembled structures, and incomplete knowledge of how the materials are processed in vivo. PMID:20091870

  4. Micro-size polyacrylamide gel electrophoresis system

    NASA Astrophysics Data System (ADS)

    Hinson, W. G.; Pipkin, J. L.; Anson, J. F.; Casciano, D. A.; Burns, E. R.

    1987-09-01

    The development and characterization of a micro-size two-dimensional polyacrylamide gel electrophoresis system is described. Some of the techniques which have evolved with use of the system are also discussed. This apparatus has unique features which provide advantages over other small scale units. Up to ten first- and second-dimension gels can be processed simultaneously with excellent resolution of protein regions. Consistent reproducibility is possible from protein samples as small as 400 ng and individual protein regions as small as 1 pg can be visualized by silver staining of the two-dimensional gels. Similar sensitivities are achieved in autoradiographs of 3H-labeled proteins extracted from the nuclei of cultured cells. The application of this system in conjunction with flow cytometric examination of nuclear DNA and electrostatic cell sorting of specific cell nuclei to provide homogeneous sample populations, allows subtle variations in isotope incorporation in proteins to be detected; whereas many times in generalized tissue samples these changes are masked. Also, these techniques elucidate the effects of external stimuli (chemicals, drugs, or environment) on protein synthesis and phosphorylation for analyses and comparison. Fabrication drawings are available upon request.

  5. Proliferation and harvest of human mesenchymal stem cells using new thermoresponsive nanocomposite gels.

    PubMed

    Kotobuki, Noriko; Murata, Kazutaka; Haraguchi, Kazutoshi

    2013-02-01

    For tissue engineering and regenerative medicine, stem cells should be effectively cultured in vitro. New thermoresponsive nanocomposite gels (MD-NC gels), consisting of inorganic clay (hectorite) and copolymers composed of hydrophobic 2-methoxyethyl acrylate (MEA) and hydrophilic N,N-dimethylacrylamide (DMAA) units, could be applied in cell culture and cell harvesting without trypsinization, specifically using mesenchymal stem cells (MSCs). The composition of the MD-NC gel (the ratio of the two monomer types and the clay content) was found to determine its swelling properties in the culture medium, thermosensitivity, protein adsorption, and cell attachment and proliferation. Various kinds of human cells, including MSCs, osteoblast (HOS) cells, fibroblast (NHDF) cells, and epithelial cells could be effectively cultured on MD-NC gels. In particular, on an MD10-NC2 gel with relatively low DMAA and clay content, the cells could be harvested by decreasing the temperature, either as a cell sheet (MSCs or NHDF cells) or as a population of suspension cells (HOS cells). Further, it was found that the MD10-NC2 gel is suitable for stem cell differentiation. Because of their thermosensitivity, controllable modulus, and surface properties, MD-NC gels are promising cell culture substrates useful for tissue engineering and regenerative medicine. PMID:22926940

  6. Oscillating Cell Culture Bioreactor

    NASA Technical Reports Server (NTRS)

    Freed, Lisa E.; Cheng, Mingyu; Moretti, Matteo G.

    2010-01-01

    To better exploit the principles of gas transport and mass transport during the processes of cell seeding of 3D scaffolds and in vitro culture of 3D tissue engineered constructs, the oscillatory cell culture bioreactor provides a flow of cell suspensions and culture media directly through a porous 3D scaffold (during cell seeding) and a 3D construct (during subsequent cultivation) within a highly gas-permeable closed-loop tube. This design is simple, modular, and flexible, and its component parts are easy to assemble and operate, and are inexpensive. Chamber volume can be very low, but can be easily scaled up. This innovation is well suited to work with different biological specimens, particularly with cells having high oxygen requirements and/or shear sensitivity, and different scaffold structures and dimensions. The closed-loop changer is highly gas permeable to allow efficient gas exchange during the cell seeding/culturing process. A porous scaffold, which may be seeded with cells, is fixed by means of a scaffold holder to the chamber wall with scaffold/construct orientation with respect to the chamber determined by the geometry of the scaffold holder. A fluid, with/without biological specimens, is added to the chamber such that all, or most, of the air is displaced (i.e., with or without an enclosed air bubble). Motion is applied to the chamber within a controlled environment (e.g., oscillatory motion within a humidified 37 C incubator). Movement of the chamber induces relative motion of the scaffold/construct with respect to the fluid. In case the fluid is a cell suspension, cells will come into contact with the scaffold and eventually adhere to it. Alternatively, cells can be seeded on scaffolds by gel entrapment prior to bioreactor cultivation. Subsequently, the oscillatory cell culture bioreactor will provide efficient gas exchange (i.e., of oxygen and carbon dioxide, as required for viability of metabolically active cells) and controlled levels of fluid

  7. Homogeneity of gels and gel-derived glasses

    NASA Technical Reports Server (NTRS)

    Mukherjee, S. P.

    1984-01-01

    The significance and implications of gel preparation procedures in controlling the homogeneity of multicomponent oxide gels are discussed. The role of physicochemical factors such as the structure and chemical reactivities of alkoxides, the formation of double-metal alkoxides, and the nature of solvent(s) are critically analyzed in the context of homogeneity of gels during gelation. Three procedures for preparing gels in the SiO2-B2O3-Na2O system are examined in the context of cation distribution. Light scattering results for glasses in the SiO2-B2O3-Na2O system prepared by both the gel technique and the conventional technique are examined.

  8. Hom Gel'fand-Dorfman bialgebras and Hom-Lie conformal algebras

    SciTech Connect

    Yuan, Lamei

    2014-04-15

    The aim of this paper is to introduce the notions of Hom Gel'fand-Dorfman bialgebra and Hom-Lie conformal algebra. In this paper, we give four constructions of Hom Gel'fand-Dorfman bialgebras. Also, we provide a general construction of Hom-Lie conformal algebras from Hom-Lie algebras. Finally, we prove that a Hom Gel'fand-Dorfman bialgebra is equivalent to a Hom-Lie conformal algebra of degree 2.

  9. Antimicrobial Graft Copolymer Gels.

    PubMed

    Harvey, Amanda C; Madsen, Jeppe; Douglas, C W Ian; MacNeil, Sheila; Armes, Steven P

    2016-08-01

    In view of the growing worldwide rise in microbial resistance, there is considerable interest in designing new antimicrobial copolymers. The aim of the current study was to investigate the relationship between antimicrobial activity and copolymer composition/architecture to gain a better understanding of their mechanism of action. Specifically, the antibacterial activity of several copolymers based on 2-(methacryloyloxy)ethyl phosphorylcholine [MPC] and 2-hydroxypropyl methacrylate (HPMA) toward Staphylococcus aureus was examined. Both block and graft copolymers were synthesized using either atom transfer radical polymerization or reversible addition-fragmentation chain transfer polymerization and characterized via (1)H NMR, gel permeation chromatography, rheology, and surface tensiometry. Antimicrobial activity was assessed using a range of well-known assays, including direct contact, live/dead staining, and the release of lactate dehydrogenase (LDH), while transmission electron microscopy was used to study the morphology of the bacteria before and after the addition of various copolymers. As expected, PMPC homopolymer was biocompatible but possessed no discernible antimicrobial activity. PMPC-based graft copolymers comprising PHPMA side chains (i.e. PMPC-g-PHPMA) significantly reduced both bacterial growth and viability. In contrast, a PMPC-PHPMA diblock copolymer comprising a PMPC stabilizer block and a hydrophobic core-forming PHPMA block did not exhibit any antimicrobial activity, although it did form a biocompatible worm gel. Surface tensiometry studies and LDH release assays suggest that the PMPC-g-PHPMA graft copolymer exhibits surfactant-like activity. Thus, the observed antimicrobial activity is likely to be the result of the weakly hydrophobic PHPMA chains penetrating (and hence rupturing) the bacterial membrane. PMID:27409712

  10. Silver staining of proteins in polyacrylamide gels

    PubMed Central

    Chevallet, Mireille; Luche, Sylvie; Rabilloud, Thierry

    2006-01-01

    Silver staining is used to detect proteins after electrophoretic separation on polyacrylamide gels. It combines excellent sensitivity (in the low nanogram range) whilst using very simple and cheap equipment and chemicals. It is compatible with downstream processing such as mass spectrometry analysis after protein digestion. The sequential phases of silver staining are protein fixation, then sensitization, then silver impregnation and finally image development. Several variants of silver staining are described here, which can be completed in a time range from 2 hours to one day after the end of the electrophoretic separation. Once completed, the stain is stable for several weeks PMID:17487168

  11. Nanocrystal/sol-gel nanocomposites

    DOEpatents

    Petruska, Melissa A.; Klimov, Victor L.

    2012-06-12

    The present invention is directed to solid composites including colloidal nanocrystals within a sol-gel host or matrix and to processes of forming such solid composites. The present invention is further directed to alcohol soluble colloidal nanocrystals useful in formation of sol-gel based solid composites

  12. Nanocrystal/sol-gel nanocomposites

    DOEpatents

    Petruska, Melissa A.; Klimov, Victor L.

    2007-06-05

    The present invention is directed to solid composites including colloidal nanocrystals within a sol-gel host or matrix and to processes of forming such solid composites. The present invention is further directed to alcohol soluble colloidal nanocrystals useful in formation of sol-gel based solid composites.

  13. Crystallization of steroids in gels

    NASA Astrophysics Data System (ADS)

    Kalkura, S. Narayana; Devanarayanan, S.

    1991-03-01

    The crystal growth and characterization of certain steriods, viz., cholesterol, cholesteryl acetate, β-sitosterol, progesterone and testosterone, in a silica gel medium is discussed. The present study shows that the single test tube diffusion method can be used to grow crystals of steroids in a silica gel medium by the reduction of steroid solubility.

  14. Comparison effect of azithromycin gel 2% with clindamycin gel 1% in patients with acne

    PubMed Central

    Mokhtari, Fatemeh; Faghihi, Gita; Basiri, Akram; Farhadi, Sadaf; Nilforoushzadeh, Mohammadali; Behfar, Shadi

    2016-01-01

    Background: Acne vulgaris is the most common skin disease. Local and systemic antimicrobial drugs are used for its treatment. But increasing resistance of Propionibacterium acnes to antibiotics has been reported. Materials and Methods: In a double-blind clinical trial, 40 patients with mild to moderate acne vulgaris were recruited. one side of the face was treated with Clindamycin Gel 1% and the other side with Azithromycin Topical Gel 2% BID for 8 weeks and then they were assessed. Results: Average age was 21. 8 ± 7 years. 82.5% of them were female. Average number of papules, pustules and comedones was similarly reduced in both groups and, no significant difference was observed between the two groups (P > 0.05, repeated measurs ANOVA). The mean indexes of ASI and TLC also significantly decreased during treatment in both groups, no significant difference was observed between the two groups. (P > 0.05, repeated measurs ANOVA). Also, impact of both drugs on papules and pustules was 2-3 times greater than the effect on comedones. Average satisfaction score was not significant between the two groups (P = 0.6, repeated measurs ANOVA). finally, frequency distribution of complications was not significant between the two groups (P > 0.05, Fisher Exact test). Conclusion: Azithromycin gel has medical impact at least similar to Clindamycin Gel in treatment of mild to moderate acne vulgaris, and it may be consider as suitable drug for resistant acne to conventional topical therapy. PMID:27169103

  15. Globalizing Education for Engineering and Science Students: A FIPSE Project Model for "Cross-Cultural Studies of Science and Technology." Final Report.

    ERIC Educational Resources Information Center

    Koller, John M.

    This report describes a project at Rensselaer Polytechnic Institute (New York) to develop a curriculum that focuses on the social construction and use of science and technology in diverse cultural contexts. The program consists of both a minor and a three-course concentration on cross-cultural studies of science and technology. Courses covered…

  16. Shallow Algal Mass Culture Systems for the Production of Oils: Final Report on Work Carried Out 8/16/84 - 6/15/85

    SciTech Connect

    Laws, E. A.

    1985-01-01

    The objective of this project was to improve the technology of outdoor mass culture of microa1gae for oil production by investigation of species/strains, optimization of culture conditions and development of strategies that increase efficiency and improve yield.

  17. Growth of Normal Mouse Vaginal Epithelial Cells in and on Collagen Gels

    NASA Astrophysics Data System (ADS)

    Iguchi, Taisen; Uchima, Francis-Dean A.; Ostrander, Patricia L.; Bern, Howard A.

    1983-06-01

    Sustained growth in primary culture of vaginal epithelial cells from ovariectomized adult BALB/cCrg1 mice embedded within or seeded on collagen gel matrix was achieved in a serum-free medium composed of Ham's F-12 medium/Dulbecco's modified Eagle's medium, 1:1 (vol/vol), supplemented with insulin, bovine serum albumin fraction V, epidermal growth factor, cholera toxin, and transferrin. Three-dimensional growth of vaginal epithelial cells occurred inside the collagen gel matrix. Cell numbers increased 4- to 8-fold in collagen gel and about 4-fold on collagen gel after 9-10 days in culture. The effect of 17β -estradiol (0.00018-180 nM in gel or 0.018-180 nM on gel) and diethylstilbestrol (DES; 0.0186-186 nM in gel) on the growth of vaginal epithelial cells was examined. The addition of estrogen did not enhance the growth of vaginal epithelial cells during this time period either in the complete medium or in a suboptimal medium. Cultures on floating collagen gels in the serum-free medium are composed of 1-3 cell layers with superficial cornification. Estrogen does not appear to be a direct mitogen for vaginal epithelial cells, at least in this system.

  18. Bouncing gel balls: Impact of soft gels onto rigid surface

    NASA Astrophysics Data System (ADS)

    Tanaka, Y.; Yamazaki, Y.; Okumura, K.

    2003-07-01

    After being thrown onto a solid substrate, very soft spherical gels bounce repeatedly. Separate rheological measurements suggest that these balls can be treated as nearly elastic. The Hertz contact deformation expected in the static (elastic) limit was observed only at very small impact velocities. For larger velocities, the gel ball deformed into flattened forms like a pancake. We measured the size of the gel balls at the maximal deformation and the contact time as a function of velocities for samples different in the original spherical radius and the Young modulus. The experimental results revealed a number of scaling relations. To interpret these relations, we developed scaling arguments to propose a physical picture.

  19. Rheological and textural properties of pulse starch gels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The properties of starch gels from black beans, chickpeas, lentils and navy beans were investigated. Differences were shown between starch sources, and effect of starch concentration was studied. Navy bean starch had the highest peak and final viscosities in pasting tests, while black bean starch h...

  20. Thermoreversible Gel Formulations Containing Sodium Lauryl Sulfate or n-Lauroylsarcosine as Potential Topical Microbicides against Sexually Transmitted Diseases

    PubMed Central

    Roy, Sylvie; Gourde, Pierrette; Piret, Jocelyne; Désormeaux, André; Lamontagne, Julie; Haineault, Caroline; Omar, Rabeea F.; Bergeron, Michel G.

    2001-01-01

    The microbicidal efficacies of two anionic surfactants, sodium lauryl sulfate (SLS) and n-lauroylsarcosine (LS), were evaluated in cultured cells and in a murine model of herpes simplex type 2 (HSV-2) intravaginal infection. In vitro studies showed that SLS and LS were potent inhibitors of the infectivity of HSV-2 strain 333. The concentrations of SLS which inhibit viral infectivity by 50% (50% inhibitory dose) and 90% (90% inhibitory dose) were 32.67 and 46.53 μM, respectively, whereas the corresponding values for LS were 141.76 and 225.30 μM. In addition, intravaginal pretreatment of mice with thermoreversible gel formulations containing 2.5% SLS or 2.5% LS prior to the inoculation of HSV-2 strain 333 completely prevented the development of genital herpetic lesions and the lethality associated with infection. Of prime interest, no infectious virus could be detected in mouse vaginal mucosa. Both formulations still provided significant protection when viral challenge was delayed until 1 h after pretreatment. Finally, intravaginal application of gel formulations containing 2.5% SLS or 2.5% LS once daily for 14 days to rabbits did not induce significant irritations to the genital mucosa, as demonstrated from macroscopic and histopathologic examinations. These results suggest that thermoreversible gel formulations containing SLS or LS could represent potent and safe topical microbicides for the prevention of HSV-2 and possibly other sexually transmitted pathogens, including human immunodeficiency virus. PMID:11353610

  1. Non-equilibrium tuning of attractive colloidal gels

    NASA Astrophysics Data System (ADS)

    Boromand, Arman; Maia, Joao

    2015-11-01

    In colloidal gel systems, the presence of multiple interactions in multiple length scales such as Van der Waals, depletion attractions, and electrostatic repulsions makes these systems challenging from both experimental and simulation aspects. Recently, there has been growing interest to tune and manipulate the structural and dynamics properties of those systems without adjusting interparticle interactions, just by taking them out of equilibrium. In this work, we used Core-Modified Dissipative Particle Dynamics (CM-DPD) with a modified depletion potential, as a coarse-grain model to address the gel formation process in short ranged-attractive colloidal suspensions for a range of volume fractions and attraction strengths. It is suggested that at high volume fractions and near the glass transition, there is a transformation from non-bonded glass to bonded-glass for which that the effect of topological frustration (caging) will be alleviated by the presence of attractive potentials (bonding) i.e. melting during cooling. In the first part of the presentation, we discuss our similar findings for semi-dilute volume fraction of attractive bimodal colloidal gels at equilibrium, which can be explained through local densification of attractive colloidal gels. In the second part, structural and dynamics properties of arrested gels will be studied under shear and after cessation of shear to study how the different flow profiles and history will alter final morphology of the gel systems.

  2. Crystal growth of proteins, nucleic acids, and viruses in gels.

    PubMed

    Lorber, Bernard; Sauter, Claude; Théobald-Dietrich, Anne; Moreno, Abel; Schellenberger, Pascale; Robert, Marie-Claire; Capelle, Bernard; Sanglier, Sarah; Potier, Noëlle; Giegé, Richard

    2009-11-01

    Medium-sized single crystals with perfect habits and no defect producing intense and well-resolved diffraction patterns are the dream of every protein crystallographer. Crystals of biological macromolecules possessing these characteristics can be prepared within a medium in which mass transport is restricted to diffusion. Chemical gels (like polysiloxane) and physical gels (such as agarose) provide such an environment and are therefore suitable for the crystallisation of biological macromolecules. Instructions for the preparation of each type of gel are given to urge crystal growers to apply diffusive media for enhancing crystallographic quality of their crystals. Examples of quality enhancement achieved with silica and agarose gels are given. Results obtained with other substances forming gel-like media (such as lipidic phases and cellulose derivatives) are presented. Finally, the use of gels in combination with capillary tubes for counter-diffusion experiments is discussed. Methods and techniques implemented with proteins can also be applied to nucleic acids and nucleoprotein assemblies such as viruses. PMID:20005247

  3. Mechanical Failure in Colloidal Gels

    NASA Astrophysics Data System (ADS)

    Kodger, Thomas Edward

    When colloidal particles in a dispersion are made attractive, they aggregate into fractal clusters which grow to form a space-spanning network, or gel, even at low volume fractions. These gels are crucial to the rheological behavior of many personal care, food products and dispersion-based paints. The mechanical stability of these products relies on the stability of the colloidal gel network which acts as a scaffold to provide these products with desired mechanical properties and to prevent gravitational sedimentation of the dispersed components. Understanding the mechanical stability of such colloidal gels is thus of crucial importance to predict and control the properties of many soft solids. Once a colloidal gel forms, the heterogeneous structure bonded through weak physical interactions, is immediately subject to body forces, such as gravity, surface forces, such as adhesion to a container walls and shear forces; the interplay of these forces acting on the gel determines its stability. Even in the absence of external stresses, colloidal gels undergo internal rearrangements within the network that may cause the network structure to evolve gradually, in processes known as aging or coarsening or fail catastrophically, in a mechanical instability known as syneresis. Studying gel stability in the laboratory requires model colloidal system which may be tuned to eliminate these body or endogenous forces systematically. Using existing chemistry, I developed several systems to study delayed yielding by eliminating gravitational stresses through density matching and cyclic heating to induce attraction; and to study syneresis by eliminating adhesion to the container walls, altering the contact forces between colloids, and again, inducing gelation through heating. These results elucidate the varied yet concomitant mechanisms by which colloidal gels may locally or globally yield, but then reform due to the nature of the physical, or non-covalent, interactions which form

  4. Polyoxometalate-based Supramolecular Gel

    PubMed Central

    He, Peilei; Xu, Biao; Liu, Huiling; He, Su; Saleem, Faisal; Wang, Xun

    2013-01-01

    Self-assemblyings of surfactant-encapsulated Wells-Dawson polyoxometalates (SEPs) nanobuilding blocks in butanone and esters yielded supramolecular gels showing thermo and photo responsive properties. The gels can be further polymerized if unsaturated esters were used and subsequently electrospinned into nanowires and non-woven mats. The as-prepared non-woven mats have a Young's modulus as high as 542.55 MPa. It is believed that this supramolecular gel is a good platform for polyoxometalates processing. PMID:23666013

  5. Adhesive, elastomeric gel impregnating composition

    DOEpatents

    Shaw, David Glenn; Pollard, John Randolph; Brooks, Robert Aubrey

    2002-01-01

    An improved capacitor roll with alternating film and foil layers is impregnated with an adhesive, elastomeric gel composition. The gel composition is a blend of a plasticizer, a polyol, a maleic anhydride that reacts with the polyol to form a polyester, and a catalyst for the reaction. The impregnant composition is introduced to the film and foil layers while still in a liquid form and then pressure is applied to aid with impregnation. The impregnant composition is cured to form the adhesive, elastomeric gel. Pressure is maintained during curing.

  6. Dynamics of a DNA Gel

    NASA Astrophysics Data System (ADS)

    Adhikari, Ramesh; Bhattacharya, Aniket; Dogariu, Aristide

    We study in silico the properties of a gel consisting of DNA strands (modeled as semi-flexible chains) and linkers of varying flexibility, length, and topology. These linkers are envisioned and modeled as active components with additional attributes so as to mimic properties of a synthetic DNA gel containing motor proteins. We use Brownian dynamics to directly obtain frequency dependent complex shear moduli of the gel. We further carry out force spectroscopy on these computer generated gels and study the relaxation properties as a function of the important parameters of the model, e.g., densities and relative ratios of the DNAs and the linkers, the average life time of a link, etc. Our studies are relevant for designing synthetic bio-materials for both materials and medical applications.

  7. Ionogel Electrolytes through Sol-Gel Processing

    NASA Astrophysics Data System (ADS)

    Horowitz, Ariel I.

    Electrical energy needs have intensified due to the ubiquity of personal electronics, the decarbonization of energy services through electrification, and the use of intermittent renewable energy sources. Despite developments in mechanical and thermal methods, electrochemical technologies are the most convenient and effective means of storing electrical energy. These technologies include both electrochemical cells, commonly called batteries, and electrochemical double-layer capacitors, or "supercapacitors", which store energy electrostatically. Both device types require an ion-conducting electrolyte. Current devices use solutions of complex salts in organic solvents, leading to both toxicity and flammability concerns. These drawbacks can be avoided by replacing conventional electrolytes with room-temperature molten salts, known as ionic liquids (ILs). ILs are non-volatile, non-flammable, and offer high conductivity and good electrochemical stability. Device mass can be reduced by combining ILs with a solid scaffold material to form an "ionogel," further improving performance metrics. In this work, sol-gel chemistry is explored as a means of forming ionogel electrolytes. Sol-gel chemistry is a solution-based, industrially-relevant, well-studied technique by which solids such as silica can be formed in situ. Previous works used a simple acid-catalyzed sol-gel reaction to create brittle, glassy ionogels. Here, both the range of products that can be accomplished through sol-gel processing and the understanding of interactions between ILs and the sol-gel reaction network are greatly expanded. This work introduces novel ionogel materials, including soft and compliant silica-supported ionogels and PDMS-supported ionogels. The impacts of the reactive formulation, IL identity, and casting time are detailed. It is demonstrated that variations in formulation can lead to rapid gelation and open pore structures in the silica scaffold or slow gelation and more dense silica

  8. TOPICAL REVIEW: Polymer gel dosimetry

    NASA Astrophysics Data System (ADS)

    Baldock, C.; De Deene, Y.; Doran, S.; Ibbott, G.; Jirasek, A.; Lepage, M.; McAuley, K. B.; Oldham, M.; Schreiner, L. J.

    2010-03-01

    Polymer gel dosimeters are fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of the absorbed radiation dose. These gel dosimeters, with the capacity to uniquely record the radiation dose distribution in three-dimensions (3D), have specific advantages when compared to one-dimensional dosimeters, such as ion chambers, and two-dimensional dosimeters, such as film. These advantages are particularly significant in dosimetry situations where steep dose gradients exist such as in intensity-modulated radiation therapy (IMRT) and stereotactic radiosurgery. Polymer gel dosimeters also have specific advantages for brachytherapy dosimetry. Potential dosimetry applications include those for low-energy x-rays, high-linear energy transfer (LET) and proton therapy, radionuclide and boron capture neutron therapy dosimetries. These 3D dosimeters are radiologically soft-tissue equivalent with properties that may be modified depending on the application. The 3D radiation dose distribution in polymer gel dosimeters may be imaged using magnetic resonance imaging (MRI), optical-computerized tomography (optical-CT), x-ray CT or ultrasound. The fundamental science underpinning polymer gel dosimetry is reviewed along with the various evaluation techniques. Clinical dosimetry applications of polymer gel dosimetry are also presented.

  9. Topical Review: Polymer gel dosimetry

    PubMed Central

    Baldock, C; De Deene, Y; Doran, S; Ibbott, G; Jirasek, A; Lepage, M; McAuley, K B; Oldham, M; Schreiner, L J

    2010-01-01

    Polymer gel dosimeters are fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of the absorbed radiation dose. These gel dosimeters, with the capacity to uniquely record the radiation dose distribution in three-dimensions (3D), have specific advantages when compared to one-dimensional dosimeters, such as ion chambers, and two-dimensional dosimeters, such as film. These advantages are particularly significant in dosimetry situations where steep dose gradients exist such as in intensity-modulated radiation therapy (IMRT) and stereotactic radiosurgery. Polymer gel dosimeters also have specific advantages for brachytherapy dosimetry. Potential dosimetry applications include those for low-energy x-rays, high-linear energy transfer (LET) and proton therapy, radionuclide and boron capture neutron therapy dosimetries. These 3D dosimeters are radiologically soft-tissue equivalent with properties that may be modified depending on the application. The 3D radiation dose distribution in polymer gel dosimeters may be imaged using magnetic resonance imaging (MRI), optical-computerized tomography (optical-CT), x-ray CT or ultrasound. The fundamental science underpinning polymer gel dosimetry is reviewed along with the various evaluation techniques. Clinical dosimetry applications of polymer gel dosimetry are also presented. PMID:20150687

  10. Studies of matrix vesicle-induced mineralization in a gelatin gel

    NASA Technical Reports Server (NTRS)

    Boskey, A. L.; Boyan, B. D.; Doty, S. B.; Feliciano, A.; Greer, K.; Weiland, D.; Swain, L. D.; Schwartz, Z.

    1992-01-01

    Matrix vesicles isolated from fourth-passage cultures of chondrocytes were tested for their ability to induce hydroxyapatite formation in a gelatin gel in order to gain insight into the function of matrix vesicles in in situ mineralization. These matrix vesicles did not appear to be hydroxyapatite nucleators per se since the extent of mineral accumulation in the gel diffusion system was not altered by the presence of matrix vesicles alone, and in the vesicle containing gels, mineral crystals were formed whether associated with vesicles or not. In gels with these matrix vesicles and beta-glycerophosphate, despite the presence of alkaline phosphatase activity, there was no increase in mineral deposition. This suggested that in the gel system these culture-derived vesicles did not increase local phosphate concentrations. However, when known inhibitors of mineral crystal formation and growth (proteoglycan aggregates [4 mg/ml], or ATP [1 mM], or both proteoglycan and ATP) were included in the gel, more mineral was deposited in gels with the vesicles than in comparable gels without vesicles, indicating that enzymes within these vesicles were functioning to remove the inhibition. These data support the suggestion that one function of the extracellular matrix vesicles is to transport enzymes for matrix modification.

  11. Alternative imaging modalities for polymer gel dosimetry

    NASA Astrophysics Data System (ADS)

    Jirasek, Andrew

    2010-11-01

    This review summarizes recent work in the area of imaging polymer gel dosimeters using x-ray CT imaging, ultrasound, and radiation-induced changes in gel mechanical properties. In addition, recent work in the area of Raman tomographic imaging of canine bone, in conjunction with past efforts in Raman imaging of polymer gel dosimeters, raises new possibilities for new polymer gel imaging techniques.

  12. Fibrin gel as alternative scaffold for respiratory tissue engineering.

    PubMed

    Cornelissen, Christian G; Dietrich, Maren; Krüger, Stefan; Spillner, Jan; Schmitz-Rode, Thomas; Jockenhoevel, Stefan

    2012-03-01

    Fibrin gel has proven a valuable scaffold for tissue engineering. Complex geometries can be produced by injection molding; it offers effective cell seeding and can be produced autologous. In order to evaluate its suitability for respiratory tissue engineering, we examined proliferation, functionality, and differentiation of respiratory epithelial cells on fibrin gel in comparison to culture on collagen-coated, microporous membranes. Respiratory epithelial cells formed a confluent layer by day 4, and proliferation showed no significant difference with respect to surface. Measurement of the transepithelial electrical resistance reflected the development of a confluent epithelial cell layer and the subsequent initiation of adequate ion-transfer processes. Appearance of ciliae could be detected at similar time points, and ciliary beating could be observed for cells on both surfaces. Histology and immunohistochemistry of cells grown on fibrin gel revealed the onset of adequate differentiation. As no significant differences in respiratory epithelial cells' proliferation, function, and differentiation could be observed between cells grown on fibrin gel compared to cells on a collagen-coated, microporous surface, we concluded that fibrin gel might prove a suitable scaffold for respiratory tissue engineering and merits further investigation to overcome the limitations associated with scaffolds currently in use. PMID:22009317

  13. Rheological behavior of Slide Ring Gels.

    NASA Astrophysics Data System (ADS)

    Sharma, Vivek; Park, Jong Seung; Park, Jung O.; Srinivasarao, Mohan

    2006-03-01

    Slide ring gels were synthesized by chemically crosslinking, sparsely populated α-cyclodextrin (α-CD) present on the polyrotaxanes consisting of α-CD and polyethylene glycol (PEG). [1] Unlike physically or chemically crosslinked gels, slide ring gels are topological gels where crosslinks can slide along the chain. [2] We investigate the rheological behavior of these gels swollen in water and compare their viscoelastic properties to those of physical and chemical gels. We also study the equilibrium swelling behavior of these gels. [1] Okumura and Ito, Adv. Mater. 2001, 13, 485 [2] C. Zhao et al, J. Phys. Cond. Mat. 2005, 17, S2841

  14. Degradation of mix hydrocarbons by immobilized cells of mix culture using a trickle fluidized bed reactor. Final report: June 1992--June 1994

    SciTech Connect

    Chapatwala, K.D.

    1994-12-01

    The microorganisms capable of degrading mix hydrocarbons were isolated from the soil samples collected from the hydrocarbon contaminated sites. The mix cultures were identified as Pseudomonas acidovorans, Flavobacterium indoltheticum and Phyllobacterium rubiaceum. The bacterial cells of mix cultures were immobilized in calcium-alginate solution in the form of beads. A trickle fluidized bed air-uplift-type reactor designed to study the degradation of mix hydrocarbons was filled with 0.85% normal saline containing the immobilized cells of mix culture. The immobilized beads were aerated with different amounts of CO{sub 2}-free air. The normal saline saturated with BTXs was circulated in the bioreactors at the rate of 2--4 ml/min. The biodegradation of BTXs by the immobilized beads of mix culture was monitored by determining the concentrations of the BTXs and the metabolites formed during their degradation in the samples at regular intervals using GC. The peaks obtained through the degradation of BTXs were not identified and quantified in this study.

  15. Educare: Evaluation of a Transition Program for Culturally Disadvantaged and Educationally Handicapped Youth. Final Performance Report, 9/1/85 to 10/31/87.

    ERIC Educational Resources Information Center

    Miner, David; And Others

    The Transition Instructional Program was designed to provide transition services to a culturally insulated group of dropout, migrant, bilingual youth of ethnic minority origin, a significant number of whom were adjudicated, handicapped, or limited English speaking. The project utilized experiential instructional techniques to promote the subjects'…

  16. A STUDY OF THE CONCENTRATION OF EDUCATIONAL MEDIA RESOURCES TO ASSIST IN CERTAIN EDUCATION PROGRAMS OF NATIONAL CONCERN. PART 1, EDUCATION OF THE CULTURALLY DISADVANTAGED. FINAL REPORT.

    ERIC Educational Resources Information Center

    DAVIS, O.L., JR.; MATHEWS, VIRGINIA H.

    THE ROLE OF EDUCATIONAL MEDIA IN THE EDUCATION OF THE CULTURALLY DISADVANTAGED WAS ANALYZED BY A COUNCIL SUBCOMMITTEE, APPOINTED IN MAY 1965. BASIC FINDINGS INCLUDE--(1) MEDIA RESOURCES SEEMED TO BE BOTH LITTLE USED, AND INEFFECTIVELY USED, (2) PROGRAM ADMINISTRATORS SEEMED TO BE UNAWARE OF THE AVAILABILITY AND EFFECTIVENESS OF MEDIA RESOURCES,…

  17. The Change in Self-Image of Oglala Sioux Ninth Grade Students Through the Development and Testing of an Indian Culture Curriculum. Final Report.

    ERIC Educational Resources Information Center

    One Feather, Vivian

    To enable the student to better his self-image, this project endeavors to give the student opportunity to acquire factual knowledge as well as new experience and skills. Through an integrated program of instructional materials, the 9th grade Oglala Sioux student studies the history and culture of the Oglala people on the Pine Ridge Indian…

  18. Implementation of an Annual Economic Data Series on Arts and Cultural Organizations. Final Report on Phase I, Volume 1, Narrative [and] Volume 2, Appendices.

    ERIC Educational Resources Information Center

    Informatics, Inc., Rockville, MD.

    The developmental work or phase 1 of a study which will collect information on the operational and financial conditions of the arts and cultural organizations which make application to the National Endowment for the Arts (NEA) for grant support is described. As part of the Economic Data Series, the report will provide the Endowment with…

  19. A Review of the Research Literature on the Influences of Culturally Based Education on the Academic Performance of Native American Students. Final Paper.

    ERIC Educational Resources Information Center

    Demmert, William G., Jr.; Towner, John C.

    There is a widespread, firm belief among Native American communities (American Indians, Alaska Natives, Native Hawaiians) and among professional Native educators that meaningful educational experiences require an appropriate language and cultural context. From their perspective, such context supports the traditions, knowledge, and language(s) of…

  20. Feeding Frequency Affects Cultured Rat Pituitary Cells in Low Gravity

    NASA Technical Reports Server (NTRS)

    Hymer, W. C.; Grindeland, R. E.; Salada, T.; Cenci, R.; Krishnan, K.; Mukai, C.; Nagaoka, S.

    1996-01-01

    In this report, we describe the results of a rat pituitary cell culture experiment done on STS-65 in which the effect of cell feeding on the release of the six anterior pituitary hormones was studied. We found complex microgravity related interactions between the frequency of cell feeding and the quantity and quality (i.e. biological activity) of some of the six hormones released in flight. Analyses of growth hormone (GH) released from cells into culture media on different mission days using gel filtration and ion exchange chromatography yielded qualitatively similar results between ground and flight samples. Lack of cell feeding resulted in extensive cell clumping in flight (but not ground) cultures. Vigorous fibroblast growth occurred in both ground and flight cultures fed 4 times. These results are interpreted within the context of autocrine and or paracrine feedback interactions. Finally the payload specialist successfully prepared a fresh trypsin solution in microgravity, detached the cells from their surface and reinserted them back into the culture chamber. These cells reattached and continued to release hormone in microgravity. In summary, this experiment shows that pituitary cells are microgravity sensitive and that coupled operations routinely associated with laboratory cel1 culture can also be accomplished in low gravity.

  1. Total internal reflection and dynamic light scattering microscopy of gels

    NASA Astrophysics Data System (ADS)

    Gregor, Brian F.

    Two different techniques which apply optical microscopy in novel ways to the study of biological systems and materials were built and applied to several samples. The first is a system for adapting the well-known technique of dynamic light scattering (DLS) to an optical microscope. This can detect and scatter light from very small volumes, as compared to standard DLS which studies light scattering from volumes 1000x larger. The small scattering volume also allows for the observation of nonergodic dynamics in appropriate samples. Porcine gastric mucin (PGM) forms a gel at low pH which lines the epithelial cell layer and acts as a protective barrier against the acidic stomach environment. The dynamics and microscopic viscosity of PGM at different pH levels is studied using polystyrene microspheres as tracer particles. The microscopic viscosity and microrheological properties of the commercial basement membrane Matrigel are also studied with this instrument. Matrigel is frequently used to culture cells and its properties remain poorly determined. Well-characterized and purely synthetic Matrigel substitutes will need to have the correct rheological and morphological characteristics. The second instrument designed and built is a microscope which uses an interferometry technique to achieve an improvement in resolution 2.5x better in one dimension than the Abbe diffraction limit. The technique is based upon the interference of the evanescent field generated on the surface of a prism by a laser in a total internal reflection geometry. The enhanced resolution is demonstrated with fluorescent samples. Additionally. Raman imaging microscopy is demonstrated using the evanescent field in resonant and non-resonant samples, although attempts at applying the enhanced resolution technique to the Raman images were ultimately unsuccessful. Applications of this instrument include high resolution imaging of cell membranes and macroscopic structures in gels and proteins. Finally, a third

  2. THERMAL DETECTION OF DNA AND PROTEINS DURING GEL ELECTROPHORESIS

    SciTech Connect

    R. JOHNSTON

    2000-08-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project was to try to detect unstained, untagged, unlabeled DNA bands in real-time during gel electrophoresis using simple thermal measurements. The technical and ES&H advantages to this approach could potentially be quite significant, especially given the extreme importance of gel electrophoresis to a wide variety of practical and research fields. The project was unable to demonstrate sufficient thermal sensitivity to detect DNA bands. It is clear that we still do not understand the gel electrophoresis phenomenon very well. The temperature control techniques developed during the course of this project have other useful applications.

  3. Thixotropic gel for vadose zone remediation

    DOEpatents

    Riha, Brian D.

    2012-07-03

    A thixotropic gel suitable for use in subsurface bioremediation is provided along with a process of using the gel. The thixotropic gel provides a non-migrating injectable substrate that can provide below ground barrier properties. In addition, the gel components provide for a favorable environment in which certain contaminants are preferentially sequestered in the gel and subsequently remediated by either indigenous or introduced microorganisms.

  4. Thixotropic gel for vadose zone remediation

    DOEpatents

    Rhia, Brian D.

    2011-03-01

    A thixotropic gel suitable for use in subsurface bioremediation is provided along with a process of using the gel. The thixotropic gel provides a non-migrating injectable substrate that can provide below ground barrier properties. In addition, the gel components provide for a favorable environment in which certain contaminants are preferentially sequestered in the gel and subsequently remediated by either indigenous or introduced microorganisms.

  5. Thixotropic gel for vadose zone remediation

    DOEpatents

    Riha, Brian D.; Looney, Brian B.

    2015-10-27

    A thixotropic gel suitable for use in subsurface bioremediation is provided along with a process of using the gel. The thixotropic gel provides a non-migrating injectable substrate that can provide below ground barrier properties. In addition, the gel components provide for a favorable environment in which certain contaminants are preferentially sequestered in the gel and subsequently remediated by either indigenous or introduced microorganisms.

  6. Automatic and quantitative measurement of collagen gel contraction using model-guided segmentation

    NASA Astrophysics Data System (ADS)

    Chen, Hsin-Chen; Yang, Tai-Hua; Thoreson, Andrew R.; Zhao, Chunfeng; Amadio, Peter C.; Sun, Yung-Nien; Su, Fong-Chin; An, Kai-Nan

    2013-08-01

    Quantitative measurement of collagen gel contraction plays a critical role in the field of tissue engineering because it provides spatial-temporal assessment (e.g., changes of gel area and diameter during the contraction process) reflecting the cell behavior and tissue material properties. So far the assessment of collagen gels relies on manual segmentation, which is time-consuming and suffers from serious intra- and inter-observer variability. In this study, we propose an automatic method combining various image processing techniques to resolve these problems. The proposed method first detects the maximal feasible contraction range of circular references (e.g., culture dish) and avoids the interference of irrelevant objects in the given image. Then, a three-step color conversion strategy is applied to normalize and enhance the contrast between the gel and background. We subsequently introduce a deformable circular model which utilizes regional intensity contrast and circular shape constraint to locate the gel boundary. An adaptive weighting scheme was employed to coordinate the model behavior, so that the proposed system can overcome variations of gel boundary appearances at different contraction stages. Two measurements of collagen gels (i.e., area and diameter) can readily be obtained based on the segmentation results. Experimental results, including 120 gel images for accuracy validation, showed high agreement between the proposed method and manual segmentation with an average dice similarity coefficient larger than 0.95. The results also demonstrated obvious improvement in gel contours obtained by the proposed method over two popular, generic segmentation methods.

  7. Gel placement in fractured systems

    SciTech Connect

    Seright, R.S.

    1995-11-01

    This paper examines several factors that can have an important effect on gel placement in fractured systems, including gelant viscosity, degree of gelation, and gravity. For an effective gel treatment, the conductivity of the fracture must be reduced and a viable flow path must remain open between the wellbore and mobile oil in the reservoir. During placement, the gelant that``leaks off`` from the fracture into the rock plays an important role in determining how well a gel treatment will reduce channeling. For a given volume of gelant injected the distance of gelant leakoff is greater for a viscous gelant than for a low-viscosity gelant. In one method to minimize gelant leakoff, sufficient gelation is designed to occur before the gelant leaves the wellbore. The authors investigated this approach in numerous experiments with both fractured and unfractured cores. They studied Cr(III)/acetate/hydrolyzed polyacrylamide (HPAM), resorcinol/formaldehyde, Cr(III)/xanthan, aluminum/citrate/HPAM, and other gelants and gels with various delay times between gelant preparation and injection. Their results suggest both hope and caution concerning the injection of gels into fractured systems.

  8. Kefiran-alginate gel microspheres for oral delivery of ciprofloxacin.

    PubMed

    Blandón, Lina M; Islan, German A; Castro, Guillermo R; Noseda, Miguel D; Thomaz-Soccol, Vanete; Soccol, Carlos R

    2016-09-01

    Ciprofloxacin is a broad-spectrum antibiotic associated with gastric and intestinal side effects after extended oral administration. Alginate is a biopolymer commonly employed in gel synthesis by ionotropic gelation, but unstable in the presence of biological metal-chelating compounds and/or under dried conditions. Kefiran is a microbial biopolymer able to form gels with the advantage of displaying antimicrobial activity. In the present study, kefiran-alginate gel microspheres were developed to encapsulate ciprofloxacin for antimicrobial controlled release and enhanced bactericidal effect against common pathogens. Scanning electron microscopy (SEM) analysis of the hybrid gel microspheres showed a spherical structure with a smoother surface compared to alginate gel matrices. In vitro release of ciprofloxacin from kefiran-alginate microspheres was less than 3.0% and 5.0% at pH 1.2 (stomach), and 5.0% and 25.0% at pH 7.4 (intestine) in 3 and 21h, respectively. Fourier transform infrared spectroscopy (FTIR) of ciprofloxacin-kefiran showed the displacement of typical bands of ciprofloxacin and kefiran, suggesting a cooperative interaction by hydrogen bridges between both molecules. Additionally, the thermal analysis of ciprofloxacin-kefiran showed a protective effect of the biopolymer against ciprofloxacin degradation at high temperatures. Finally, antimicrobial assays of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhymurium, and Staphylococcus aureus demonstrated the synergic effect between ciprofloxacin and kefiran against the tested microorganisms. PMID:27289312

  9. Studies on Phase Separation in a-PMMA/PEG Gels

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoliang

    2005-03-01

    Stereo-irregular atactic poly(methyl methacrylate) (a-PMMA) is known incapable of forming gels in common solvents, irrespective of the solvent quality. However, we recently found a rigid opaque thermal-reversible a-PMMA gel in the solvent of the polyethyl glycol oligomer (PEG) (the PEG molecule mass differ from 400 to 4000 were used). FT-IR, dynamic mechanical temperature analysis and Solid state NMR measurements were used to study the gel properties and gelation mechanism. The in situ IR studies in a-PMMA/PEG gel suggested that some a-PMMA segments were in the aggregated state in solution, which became a node in the solution. With decreasing temperature, the fraction of aggregated a-PMMA in solution increases, resulting in the formation of physical network finally. Spin diffusion was used to determine the size (ξ) of domains in the gels. We found that, a-PMMA/PEG4000 was miscible (ξ ˜ 9nm), while a-PMMA/PEG1000 was micro phase separated (ξ ˜ 57nm) and a-PMMA/PEG400 was macro phase separated (ξ > 300nm). The a-PMMA self-aggregation was attributed to the depletion interaction that becomes important in the case of middle-sized solvents.

  10. Posing for a picture: vesicle immobilization in agarose gel.

    PubMed

    Lira, Rafael B; Steinkühler, Jan; Knorr, Roland L; Dimova, Rumiana; Riske, Karin A

    2016-01-01

    Taking a photo typically requires the object of interest to stand still. In science, imaging is potentiated by optical and electron microscopy. However, living and soft matter are not still. Thus, biological preparations for microscopy usually include a fixation step. Similarly, immobilization strategies are required for or substantially facilitate imaging of cells or lipid vesicles, and even more so for acquiring high-quality data via fluorescence-based techniques. Here, we describe a simple yet efficient method to immobilize objects such as lipid vesicles with sizes between 0.1 and 100 μm using agarose gel. We show that while large and giant unilamellar vesicles (LUVs and GUVs) can be caged in the pockets of the gel meshwork, small molecules, proteins and micelles remain free to diffuse through the gel and interact with membranes as in agarose-free solutions, and complex biochemical reactions involving several proteins can proceed in the gel. At the same time, immobilization in agarose has no adverse effect on the GUV size and stability. By applying techniques such as FRAP and FCS, we show that the lateral diffusion of lipids is not affected by the gel. Finally, our immobilization strategy allows capturing high-resolution 3D images of GUVs. PMID:27140695

  11. Posing for a picture: vesicle immobilization in agarose gel

    PubMed Central

    Lira, Rafael B.; Steinkühler, Jan; Knorr, Roland L.; Dimova, Rumiana; Riske, Karin A.

    2016-01-01

    Taking a photo typically requires the object of interest to stand still. In science, imaging is potentiated by optical and electron microscopy. However, living and soft matter are not still. Thus, biological preparations for microscopy usually include a fixation step. Similarly, immobilization strategies are required for or substantially facilitate imaging of cells or lipid vesicles, and even more so for acquiring high-quality data via fluorescence-based techniques. Here, we describe a simple yet efficient method to immobilize objects such as lipid vesicles with sizes between 0.1 and 100 μm using agarose gel. We show that while large and giant unilamellar vesicles (LUVs and GUVs) can be caged in the pockets of the gel meshwork, small molecules, proteins and micelles remain free to diffuse through the gel and interact with membranes as in agarose-free solutions, and complex biochemical reactions involving several proteins can proceed in the gel. At the same time, immobilization in agarose has no adverse effect on the GUV size and stability. By applying techniques such as FRAP and FCS, we show that the lateral diffusion of lipids is not affected by the gel. Finally, our immobilization strategy allows capturing high-resolution 3D images of GUVs. PMID:27140695

  12. Development and Characterization of NMR Measurements for Polymer Gel Dosimetry

    NASA Astrophysics Data System (ADS)

    Kwong, Zachary; Whitney, Heather

    2012-03-01

    Polymer gel dosimeters are systems of water, gelatin, and monomers which form polymers upon irradiation. The gelatin matrix retains dose distribution in 3D form, facilitating truly integrated measurements of complex dose plans for radiation therapy. Polymer gels have two proton pools coupled by exchange: free solvent protons and bound polymerized macromolecular protons. Measuring magnetization transfer (MT) and relaxation affords useful insights into particle rigidity and chemical exchange effects on relaxation in polymer gels. Polymer gel dose response has been previously quantified with several techniques, most often in terms of MRI parameters, usually at field strengths of 1.5 T and below. The research described here investigates the dose response of a revised MAGIC gel dosimeter via both high-field imaging and simpler nuclear magnetic resonance (NMR) spectroscopy. This includes both transverse and longitudinal relaxation rates (R2 and R1) and quantitative MT parameters. We investigated estimating polymer molecular weight for a given applied dose using the Rouse model and R2 data from the imaging study. Finally, we began development of NMR methods for studying dose response, requiring adaption of NMR experiments to accommodate for radiation damping.

  13. Structural Evolution of Silica Gel and Silsesquioxane Using Thermal Curing.

    PubMed

    Hu, Nan; Rao, YuanQiao; Sun, Shengtong; Hou, Lei; Wu, Peiyi; Fan, Shaojuan; Ye, Bangjiao

    2016-08-01

    The curing of coatings of two types of siloxane containing materials, silica gel and silsesquioxane, at a modest temperature (<280℃) was studied with in situ heating Fourier transform infrared spectroscopy (FT-IR) in combination with perturbation correlation moving window (PCMW) and two-dimensional correlation spectroscopy (2D-COS) analyses. The result revealed detailed structural evolution of these two different gels. When the silica gel was heated, (Si-O)6 rings appeared from the random Si-O-Si network formed after sol gel reaction, followed by condensation of silanol groups. Upon further heating, the existing (Si-O)4 rings were broken down and converted into (Si-O)6 structures, and finally isolated silanols appeared. The transition from (Si-O)4 rings to (Si-O)6 rings was observed by IR and further confirmed with positron annihilation lifetime spectroscopy (PALS). In comparison, during the curing of hybrid silsesquioxane, the condensation of silanols happens immediately upon heating without the rearrangement of Si-O-Si network. Afterwards, the fraction of (Si-O)6 ring structure increased. (Si-O)4 structures exhibited higher stability in hybrid silsesquioxanes. In addition, the amount of silanols in silsesquioxane continued to reduce without the generation of isolated silanol in the end. The different curing behavior of silsesquioxanes from silica gel originates from the organic groups in silsesquioxanes, which lowers the cross-linking density and reduces the rigidity of siloxane network. PMID:27340213

  14. Posing for a picture: vesicle immobilization in agarose gel

    NASA Astrophysics Data System (ADS)

    Lira, Rafael B.; Steinkühler, Jan; Knorr, Roland L.; Dimova, Rumiana; Riske, Karin A.

    2016-05-01

    Taking a photo typically requires the object of interest to stand still. In science, imaging is potentiated by optical and electron microscopy. However, living and soft matter are not still. Thus, biological preparations for microscopy usually include a fixation step. Similarly, immobilization strategies are required for or substantially facilitate imaging of cells or lipid vesicles, and even more so for acquiring high-quality data via fluorescence-based techniques. Here, we describe a simple yet efficient method to immobilize objects such as lipid vesicles with sizes between 0.1 and 100 μm using agarose gel. We show that while large and giant unilamellar vesicles (LUVs and GUVs) can be caged in the pockets of the gel meshwork, small molecules, proteins and micelles remain free to diffuse through the gel and interact with membranes as in agarose-free solutions, and complex biochemical reactions involving several proteins can proceed in the gel. At the same time, immobilization in agarose has no adverse effect on the GUV size and stability. By applying techniques such as FRAP and FCS, we show that the lateral diffusion of lipids is not affected by the gel. Finally, our immobilization strategy allows capturing high-resolution 3D images of GUVs.

  15. Sol-gel derived sorbents

    DOEpatents

    Sigman, Michael E.; Dindal, Amy B.

    2003-11-11

    Described is a method for producing copolymerized sol-gel derived sorbent particles for the production of copolymerized sol-gel derived sorbent material. The method for producing copolymerized sol-gel derived sorbent particles comprises adding a basic solution to an aqueous metal alkoxide mixture for a pH.ltoreq.8 to hydrolyze the metal alkoxides. Then, allowing the mixture to react at room temperature for a precalculated period of time for the mixture to undergo an increased in viscosity to obtain a desired pore size and surface area. The copolymerized mixture is then added to an immiscible, nonpolar solvent that has been heated to a sufficient temperature wherein the copolymerized mixture forms a solid upon the addition. The solid is recovered from the mixture, and is ready for use in an active sampling trap or activated for use in a passive sampling trap.

  16. Copolymers For Capillary Gel Electrophoresis

    DOEpatents

    Liu, Changsheng; Li, Qingbo

    2005-08-09

    This invention relates to an electrophoresis separation medium having a gel matrix of at least one random, linear copolymer comprising a primary comonomer and at least one secondary comonomer, wherein the comonomers are randomly distributed along the copolymer chain. The primary comonomer is an acrylamide or an acrylamide derivative that provides the primary physical, chemical, and sieving properties of the gel matrix. The at least one secondary comonomer imparts an inherent physical, chemical, or sieving property to the copolymer chain. The primary and secondary comonomers are present in a ratio sufficient to induce desired properties that optimize electrophoresis performance. The invention also relates to a method of separating a mixture of biological molecules using this gel matrix, a method of preparing the novel electrophoresis separation medium, and a capillary tube filled with the electrophoresis separation medium.

  17. Fundamentals of Polymer Gel Dosimeters

    NASA Astrophysics Data System (ADS)

    McAuley, Kim B.

    2006-12-01

    The recent literature on polymer gel dosimetry contains application papers and basic experimental studies involving polymethacrylic-acid-based and polyacrylamide-based gel dosimeters. The basic studies assess the relative merits of these two most commonly used dosimeters, and explore the effects of tetrakis hydroxymethyl phosphonium chloride (THPC) antioxidant on dosimeter performance. Polymer gel dosimeters that contain THPC or other oxygen scavengers are called normoxic dosimeters, because they can be prepared under normal atmospheric conditions, rather than in a glove box that excludes oxygen. In this review, an effort is made to explain some of the underlying chemical phenomena that affect dosimeter performance using THPC, and that lead to differences in behaviour between dosimeters made using the two types of monomer systems. Progress on the development of new more effective and less toxic dosimeters is also reported.

  18. Assessing Social and Cross-Cultural Impact of Group-Based Videodisc Technology. Final Report, October 1, 1987-December 31, 1989.

    ERIC Educational Resources Information Center

    Thorkildsen, Ron; Lowry, William H.

    This final report documents achievements of a project to assess social impact and achievement gains resulting from the use of interactive videodisc technology to teach fractions in mainstreamed classrooms across multicultural settings. Subjects (N=294) were regular upper elementary students and students with mild handicaps (MH) in Utah, Wyoming,…

  19. Nanostructure of native pectin sugar acid gels visualized by atomic force microscopy.

    PubMed

    Fishman, Marshall L; Cooke, Peter H; Coffin, David R

    2004-01-01

    Height and phase shift images of high methoxyl sugar acid gels (HMSAG) of pectin were obtained by atomic force microscopy in the tapping mode. Images revealed that pores in these gels were fluid and flattened out when measured as a function of time. These images revealed for the first time the structure of adsorbed sugar on pectin in the hydrated native gels and how the pectin framework is organized within these gels. Segmentation of images revealed that the underlying pectin framework contained combinations of rods, segmented rods, and kinked rods connected end to end and laterally. The open network of strands was similar to pectin aggregates from 5 mM NaCl solution imaged earlier by electron microscopy (Fishman et al., Arch. Biochem. Biophys. 1992, 294, 253). Area measurements revealed that the ratio of bound sugar to pectin was in excess of 100 to 1 (w/w). Furthermore, images indicated relatively small differences in the organization of native commercial citrus pectin, orange albedo pectin, and lime albedo pectin gels at optimal pH as determined in this study. The findings are consistent with earlier gel strength measurements of these gels. In addition, values of gel strength were consistent with values of molar mass and viscosity of the constituent pectins in that they increased in the same order. Finally, we demonstrated the advantage of simultaneous visualization of height and phase shift images for observing and quantitating the nanostructure of relatively soft gels which are fully hydrated with a buffer. PMID:15002992

  20. Reduced Graphene Oxide-GelMA Hybrid Hydrogels as Scaffolds for Cardiac Tissue Engineering.

    PubMed

    Shin, Su Ryon; Zihlmann, Claudio; Akbari, Mohsen; Assawes, Pribpandao; Cheung, Louis; Zhang, Kaizhen; Manoharan, Vijayan; Zhang, Yu Shrike; Yüksekkaya, Mehmet; Wan, Kai-Tak; Nikkhah, Mehdi; Dokmeci, Mehmet R; Tang, Xiaowu Shirley; Khademhosseini, Ali

    2016-07-01

    Biomaterials currently used in cardiac tissue engineering have certain limitations, such as lack of electrical conductivity and appropriate mechanical properties, which are two parameters playing a key role in regulating cardiac cell behavior. Here, the myocardial tissue constructs are engineered based on reduced graphene oxide (rGO)-incorporated gelatin methacryloyl (GelMA) hybrid hydrogels. The incorporation of rGO into the GelMA matrix significantly enhances the electrical conductivity and mechanical properties of the material. Moreover, cells cultured on composite rGO-GelMA scaffolds exhibit better biological activities such as cell viability, proliferation, and maturation compared to ones cultured on GelMA hydrogels. Cardiomyocytes show stronger contractility and faster spontaneous beating rate on rGO-GelMA hydrogel sheets compared to those on pristine GelMA hydrogels, as well as GO-GelMA hydrogel sheets with similar mechanical property and particle concentration. Our strategy of integrating rGO within a biocompatible hydrogel is expected to be broadly applicable for future biomaterial designs to improve tissue engineering outcomes. The engineered cardiac tissue constructs using rGO incorporated hybrid hydrogels can potentially provide high-fidelity tissue models for drug studies and the investigations of cardiac tissue development and/or disease processes in vitro. PMID:27254107

  1. Nonlinear elasticity of alginate gels

    NASA Astrophysics Data System (ADS)

    Hashemnejad, Seyed Meysam; Kundu, Santanu

    Alginate is a naturally occurring anionic polysaccharide extracted from brown algae. Because of biocompatibility, low toxicity, and simple gelation process, alginate gels are used in biomedical and food applications. Here, we report the rheological behavior of ionically crosslinked alginate gels, which are obtained by in situ gelation of alginates with calcium salts, in between two parallel plates of a rheometer. Strain stiffening behavior was captured using large amplitude oscillatory shear (LAOS) experiments. In addition, negative normal stress was observed for these gels, which has not been reported earlier for any polysaccharide networks. The magnitude of negative normal stress increases with applied strain and can exceed that of the shear stress at large strain. Rheological results fitted with a constitutive model that considers both stretching and bending of chains indicate that nonlinearity is likely related to the stretching of the chains between the crosslink junctions. The results provide an improved understanding of the deformation mechanism of ionically crosslinked alginate gel and the results will be important in developing synthetic extracellular matrix (ECM) from these materials.

  2. A Moderately Thermophilic Mixed Microbial Culture for Bioleaching of Chalcopyrite Concentrate at High Pulp Density

    PubMed Central

    Wang, Yuguang; Zeng, Weimin; Qiu, Guanzhou; Chen, Xinhua

    2014-01-01

    Three kinds of samples (acid mine drainage, coal mine wastewater, and thermal spring) derived from different sites were collected in China. Thereafter, these samples were combined and then inoculated into a basal salts solution in which different substrates (ferrous sulfate, elemental sulfur, and chalcopyrite) served as energy sources. After that, the mixed cultures growing on different substrates were pooled equally, resulting in a final mixed culture. After being adapted to gradually increasing pulp densities of chalcopyrite concentrate by serial subculturing for more than 2 years, the final culture was able to efficiently leach the chalcopyrite at a pulp density of 20% (wt/vol). At that pulp density, the culture extracted 60.4% of copper from the chalcopyrite in 25 days. The bacterial and archaeal diversities during adaptation were analyzed by denaturing gradient gel electrophoresis and constructing clone libraries of the 16S rRNA gene. The results show that the culture consisted mainly of four species, including Leptospirillum ferriphilum, Acidithiobacillus caldus, Sulfobacillus acidophilus, and Ferroplasma thermophilum, before adapting to a pulp density of 4%. However, L. ferriphilum could not be detected when the pulp density was greater than 4%. Real-time quantitative PCR was employed to monitor the microbial dynamics during bioleaching at a pulp density of 20%. The results show that A. caldus was the predominant species in the initial stage, while S. acidophilus rather than A. caldus became the predominant species in the middle stage. F. thermophilum accounted for the greatest proportion in the final stage. PMID:24242252

  3. Species-specific toxicity of troglitazone on rats and human by gel entrapped hepatocytes

    SciTech Connect

    Shen, Chong; Meng, Qin; Zhang, Guoliang

    2012-01-01

    Troglitazone, despite passing preclinical trials on animals, was shortly withdrawn from market due to its severe hepatotoxicity in clinic. As rat hepatocyte monolayer consistently showed sensitive troglitazone toxicity as human hepatocyte monolayer in contrast to the species-specific toxicity in vivo, this paper utilized both hepatocytes in three-dimensional culture of gel entrapment to reflect the species difference on hepatotoxicity. Rat hepatocytes in gel entrapment did not show obvious cellular damage even under a long-term exposure for 21 days while gel entrapped human hepatocytes significantly displayed oxidative stress, steatosis, mitochondrial damage and cell death at a short exposure for 4 days. As a result, the detected species-specific toxicity of troglitazone between gel entrapped rat and human hepatocytes consisted well with the situation in vivo but was in a sharp contrast to the performance of two hepatocytes by monolayer culture. Such contradictory toxicity of rat hepatocytes between monolayer and gel entrapment culture could be explained by the fact that troglitazone was cleared more rapidly in gel entrapment than in monolayer culture. Similarly, the differential clearance of troglitazone in rat and human might also explain its species-specific toxicity. Therefore, gel entrapment of hepatocytes might serve as a platform for evaluation of drug toxicity at early stage of drug development by reducing costs, increasing the likelihood of clinical success and limiting human exposure to unsafe drugs. -- Highlights: ► Species-specific toxicity of troglitazone reflected by rat/human hepatocytes ► 3D hepatocytes in 21 days’ long-term culture used for drug hepatotoxicity ► Oversensitive toxicity in hepatocyte monolayer by slow troglitazone clearance.

  4. Effect of silica gel on the cohesion, properties and biological performance of brushite cement.

    PubMed

    Alkhraisat, Mohammad Hamdan; Rueda, Carmen; Jerez, Luis Blanco; Tamimi Mariño, Faleh; Torres, Jesus; Gbureck, Uwe; Lopez Cabarcos, Enrique

    2010-01-01

    The cohesion of calcium phosphate cements can be improved by the addition of substances to either the solid or liquid phase during the setting reaction. This study reports the effect of silica gel on brushite cement cohesion. The cement was prepared using a mixture of beta-tricalcium phosphate (beta-TCP) and monocalcium phosphate monohydrate as the solid phase, while the liquid phase comprised carboxylic acids silica gel. This cement presents a shorter final setting time (FST), better cohesion and higher amount of unreacted beta-TCP than the cement prepared without silica gel. Furthermore, in vivo experiments using rabbits as an animal model showed that after 8 weeks of implantation cements modified with silica gel showed a similar new bone formation volume and more remaining graft in comparison with unmodified cements. Thus, the silica gel could be efficiently applied to reduce cement disintegration and to decrease the resorption rate of brushite cements. PMID:19523541

  5. Thickness sensing of hMSCs on collagen gel directs stem cell fate

    SciTech Connect

    Leong, Wen Shing; Tay, Chor Yong; Yu, Haiyang; Li, Ang; Wu, Shu Cheng; Duc, Duong-Hong; Lim, Chwee Teck; Tan, Lay Poh

    2010-10-15

    Research highlights: {yields} hMSCs appeared to sense thin collagen gel (130 {mu}m) with higher effective modulus as compared to thick gel (1440 {mu}m). {yields} Control of collagen gel thickness can modulate cellular behavior, even stem cell fate (neuronal vs. Quiescent). {yields} Distinct cellular behavior of hMSCs on thin and thick collagen gel suggests long range interaction of hMSCs with collagen gel. -- Abstract: Mechanically compliant substrate provides crucial biomechanical cues for multipotent stem cells to regulate cellular fates such as differentiation, proliferation and maintenance of their phenotype. Effective modulus of which cells sense is not only determined by intrinsic mechanical properties of the substrate, but also the thickness of substrate. From our study, it was found that interference from underlying rigid support at hundreds of microns away could induce significant cellular response. Human mesenchymal stem cells (hMSCs) were cultured on compliant biological gel, collagen type I, of different thickness but identical ECM composition and local stiffness. The cells sensed the thin gel (130 {mu}m) as having a higher effective modulus than the thick gel (1440 {mu}m) and this was reflected in their changes in morphology, actin fibers structure, proliferation and tissue specific gene expression. Commitment into neuronal lineage was observed on the thin gel only. Conversely, the thick gel (1440 {mu}m) was found to act like a substrate with lower effective modulus that inhibited actin fiber polymerization. Stem cells on the thick substrate did not express tissue specific genes and remained at their quiescent state. This study highlighted the need to consider not only the local modulus but also the thickness of biopolymer gel coating during modulation of cellular responses.

  6. Calculating Percent Gel For Process Control

    NASA Technical Reports Server (NTRS)

    Webster, Charles Neal; Scott, Robert O.

    1988-01-01

    Reaction state of thermosetting resin tracked to assure desired properties. Rate of gel determined as function of temperature by measuring time to gel of part of graphite fabric impregnated with Hexcel R120 (or equivalent) phenolic resin.

  7. Soft fibrin gels promote selection and growth of tumorigenic cells

    NASA Astrophysics Data System (ADS)

    Liu, Jing; Tan, Youhua; Zhang, Huafeng; Zhang, Yi; Xu, Pingwei; Chen, Junwei; Poh, Yeh-Chuin; Tang, Ke; Wang, Ning; Huang, Bo

    2012-08-01

    The identification of stem-cell-like cancer cells through conventional methods that depend on stem cell markers is often unreliable. We developed a mechanical method for selecting tumorigenic cells by culturing single cancer cells in fibrin matrices of ~100 Pa in stiffness. When cultured within these gels, primary human cancer cells or single cancer cells from mouse or human cancer cell lines grew within a few days into individual round colonies that resembled embryonic stem cell colonies. Subcutaneous or intravenous injection of 10 or 100 fibrin-cultured cells in syngeneic or severe combined immunodeficiency mice led to the formation of solid tumours at the site of injection or at the distant lung organ much more efficiently than control cancer cells selected using conventional surface marker methods or cultured on conventional rigid dishes or on soft gels. Remarkably, as few as ten such cells were able to survive and form tumours in the lungs of wild-type non-syngeneic mice.

  8. Characteristics of platelet gels combined with silk.

    PubMed

    Pallotta, Isabella; Kluge, Jonathan A; Moreau, Jodie; Calabrese, Rossella; Kaplan, David L; Balduini, Alessandra

    2014-04-01

    Platelet gel, a fibrin network containing activated platelets, is widely used in regenerative medicine due the capacity of platelet-derived growth factors to accelerate and direct healing processes. However, limitations to this approach include poor mechanical properties, relatively rapid degradation, and the lack of control of release of growth factors at the site of injection. These issues compromise the ability of platelet gels for sustained function in regenerative medicine. In the present study, a combination of platelet gels with silk fibroin gel was studied to address the above limitations. Mixing sonicated silk gels with platelet gels extended the release of growth factors without inhibiting gel-forming ability. The released growth factors were biologically active and their delivery was modified further by manipulation of the charge of the silk protein. Moreover, the silk gel augmented both the rheological properties and compressive stiffness of the platelet gel, tuned by the silk concentration and/or silk/platelet gel ratio. Silk-platelet gel injections in nude rats supported enhanced cell infiltration and blood vessel formation representing a step towards new platelet gel formulations with enhanced therapeutic impact. PMID:24480538

  9. Spring-loaded polymeric gel actuators

    DOEpatents

    Shahinpoor, Mohsen

    1995-01-01

    Spring-loaded electrically controllable polymeric gel actuators are disclosed. The polymeric gels can be polyvinyl alcohol, polyacrylic acid, or polyacrylamide, and are contained in an electrolytic solvent bath such as water plus acetone. The action of the gel is mechanically biased, allowing the expansive and contractile forces to be optimized for specific applications.

  10. Characteristics of platelet gels combined with silk

    PubMed Central

    Pallotta, Isabella; Kluge, Jonathan A.; Moreau, Jodie; Calabrese, Rossella

    2014-01-01

    Platelet gel, a fibrin network containing activated platelets, is widely used in regenerative medicine due the capacity of platelet-derived growth factors to accelerate and direct healing processes. However, limitations to this approach include poor mechanical properties, relatively rapid degradation, and the lack of control of release of growth factors at the site of injection. These issues compromise the ability of platelet gels for sustained function in regenerative medicine. In the present study, a combination of platelet gels with silk fibroin gel was studied to address the above limitations. Mixing sonicated silk gels with platelet gels extended the release of growth factors without inhibiting gel forming ability. The released growth factors were biologically active and their delivery was modified further by manipulation of the charge of the silk protein. Moreover, the silk gel augmented both the rheological properties and compressive stiffness of the platelet gel, tuned by the silk concentration and/or silk/platelet gel ratio. Silk-platelet gel injections in nude rats supported enhanced cell infiltration and blood vessel formation representing a step towards new platelet gel formulations with enhanced therapeutic impact. PMID:24480538

  11. Spring-loaded polymeric gel actuators

    DOEpatents

    Shahinpoor, M.

    1995-02-14

    Spring-loaded electrically controllable polymeric gel actuators are disclosed. The polymeric gels can be polyvinyl alcohol, polyacrylic acid, or polyacrylamide, and are contained in an electrolytic solvent bath such as water plus acetone. The action of the gel is mechanically biased, allowing the expansive and contractile forces to be optimized for specific applications. 5 figs.

  12. A clarified gel for crystal growth

    NASA Technical Reports Server (NTRS)

    Barber, P. G.; Simpson, N. R.

    1985-01-01

    A procedure for preparing clarified sodium silicate gels suitable for crystal growth is described. In the method described here, the silicate stock is clarified by pretreating it with cation exchange resins before preparing the gels. Also, a modified recipe is proposed for preparing gels to achieve improved transparency.

  13. Modulating the Rigidity and Mineralization of Collagen Gels Using Poly(Lactic-Co-Glycolic Acid) Microparticles

    PubMed Central

    DeVolder, Ross J.; Kim, Il Won; Kim, Eun-Suk

    2012-01-01

    Extensive efforts have been made to prepare osteoconductive collagen gels for the regeneration of normal bone and the pathological examination of diseased bone; however, collagen gels are often plagued by limited controllability of their rigidity and mineral deposition. This study reports a simple but efficient strategy that tunes the mechanical properties of, and apatite formation in, collagen gels by incorporating hydrolyzable poly(lactic-co-glycolic acid) (PLGA) microparticles within the gels. The PLGA microparticles are associated with the collagen fibrils and increased both the gel's elasticity and rigidity while minimally influencing its permeability. As compared with pure collagen gels, the PLGA microparticle-filled collagen gels, termed PLGA-Col hydrogels, significantly enhanced the deposition of apatite-like minerals within the gels when incubated in simulated body fluid or encapsulated with mesenchymal stem cells (MSCs) undergoing osteogenic differentiation. Finally, PLGA-Col hydrogels mineralized by differentiated MSCs led to an enhanced formation of bone-like tissues within the hydrogels. Overall, the PLGA-Col hydrogel system developed in this study will serve to improve the quality of osteoconductive matrices for both fundamental and clinical studies that are relevant to bone repair, regeneration, and pathogenesis. PMID:22480235

  14. Nanocrystal/sol-gel nanocomposites

    DOEpatents

    Klimov, Victor L.; Petruska, Melissa A.

    2010-05-25

    The present invention is directed to a process for preparing a solid composite having colloidal nanocrystals dispersed within a sol-gel matrix, the process including admixing colloidal nanocrystals with an amphiphilic polymer including hydrophilic groups selected from the group consisting of --COOH, --OH, --SO.sub.3H, --NH.sub.2, and --PO.sub.3H.sub.2 within a solvent to form an alcohol-soluble colloidal nanocrystal-polymer complex, admixing the alcohol-soluble colloidal nanocrystal-polymer complex and a sol-gel precursor material, and, forming the solid composite from the admixture. The present invention is also directed to the resultant solid composites and to the alcohol-soluble colloidal nanocrystal-polymer complexes.

  15. The Swelling of Olympic Gels

    NASA Astrophysics Data System (ADS)

    Lang, Michael; Fischer, Jakob; Werner, Marco; Sommer, Jens-Uwe

    2014-03-01

    The swelling equilibrium of Olympic gels is studied by Monte Carlo Simulations. We observe that gels consisting of flexible cyclic molecules of a higher degree of polymerization N show a smaller equilibrium swelling degree Q ~N - 0 . 28φ0- 0 . 72 for the same monomer volume fraction φ0 at network preparation. This observation is explained by a disinterpenetration process of overlapping non-concatenated polymers upon swelling. In the limit of a sufficiently large number of concatenations per cyclic molecule we expect that the equilibrium degree of swelling becomes proportional to φ0- 1 / 2 independent of N. Our results challenge current textbook models for the equilibrium degree of swelling of entangled polymer networks. Now at: Bio Systems Analysis Group, Jena Centre for Bioinformatics (JCB) and Department for Mathematics and Computer Sciences, Friedrich Schiller University of Jena, 07743 Jena, Germany.

  16. Supercoiling transformation of chemical gels.

    PubMed

    Asai, Makoto; Katashima, Takuya; Sakai, Takamasa; Shibayama, Mitsuhiro

    2015-09-28

    The swelling/deswelling behavior of chemical gels has been an unsolved problem disputed over for a long time. The Obukhov-Rubinstein-Colby model depicts the influence that swelling/deswelling has on elasticity, but its physical picture is too complicated to be sufficiently validated by experiment. In this study, we use molecular dynamics simulation to verify the validity of the molecular picture of network strands predicted by the Obukhov-Rubinstein-Colby model. We conclude that the physical picture of the Obukhov-Rubinstein-Colby model is reasonable, and furthermore the simulation can reveal the details of conformational changes in network strands during the supercoiling transformation. Our findings not only reveal the validity, but also give a better understanding of the dynamics of the swelling/deswelling behavior of chemical gels. PMID:26279149

  17. Lecithin-Linker Microemulsion Gelatin Gels for Extended Drug Delivery

    PubMed Central

    Xuan, Xiao-Yue; Cheng, Yu-Ling; Acosta, Edgar

    2012-01-01

    This article introduces the formulation of alcohol-free, lecithin microemulsion-based gels (MBGs) prepared with gelatin as gelling agent. The influence of oil, water, lecithin and hydrophilic and lipophilic additives (linkers) on the rheological properties and appearance of these gels was systematically explored using ternary phase diagrams. Clear MBGs were obtained in regions of single phase microemulsions (μEs) at room temperature. Increasing the water content in the formulation increased the elastic modulus of the gels, while increasing the oil content had the opposite effect. The hydrophilic additive (PEG-6-caprylic/capric glycerides) was shown to reduce the elastic modulus of gelatin gels, particularly at high temperatures. In contrast to anionic (AOT) μEs, the results suggest that in lecithin (nonionic) μEs, the introduction of gelatin “dehydrates” the μE. Finally, when the transdermal transport of lidocaine formulated in the parent μE and the resulting MBG were compared, only a minor retardation in the loading and release of lidocaine was observed. PMID:24300183

  18. Influence of Whitening Gel Application Protocol on Dental Color Change

    PubMed Central

    Caneppele, Taciana Marco Ferraz; Torres, Carlos Rocha Gomes; Huhtala, Maria Filomena Rocha Lima; Bresciani, Eduardo

    2015-01-01

    Objectives. To evaluate the influence of different whitening protocols on the efficacy of 35% hydrogen peroxide (HP) tooth whitening and gel pH and concentration. Material and Methods. Eighty-four enamel/dentin discs from bovine incisors were used. The baseline color was measured with a spectrophotometer. Two sessions of in-office whitening with 35% HP were performed under different protocols: G1: 3 applications of HP (10 min each) per session; G2: 1 application of 30 min per session; G3: 1 application of 40 min per session, with no gel replenishment within session for groups 2 and 3. HP titration and pH evaluation at baseline, after 10, 30, and 40 min were also performed. The final color was measured 24 h after the 1st and 2nd whitening sessions. Data were submitted to Repeated Measures ANOVA and Tukey's test. Results. For color evaluation, no differences were observed among groups after two sessions. HP titration showed no drop on concentration after 10, 30, or 40 min. The pH was 5.54 at baseline and 5.41 after 40 min. Conclusion. Replenishment or extended application time of in-office whitening gel does not affect gel pH and concentration, a fact that supports the similar effectiveness of whitening observed among the tested protocols. PMID:25866839

  19. Selective gel system for permeability profile control

    SciTech Connect

    Shu, P.

    1990-02-27

    This patent describes a process for closing pores in a more permeable zone of a formation. It comprises: placing into an aqueous solution a first composition sufficient to form ex-situ a size selective, shear thinning first gel which comprises a xanthan biopolymer, and a transitional metal ion; placing into the aqueous solution a second composition sufficient to form thermally a second in-situ gel which is substantially more resistant to formation conditions than the first gel. The composition comprises an aldehyde, and a phenolic compound; allowing the aqueous solution sufficient time to form the ex-situ gel; and injecting the aqueous solution containing the gel into the permeable zone where it reheals, is heated by the formation and thereafter forms a solid gel substantially more resistant to formation conditions than the first gel.

  20. Endosperm protein synthesis and L-(/sup 35/S)methionine incorporation in maize kernels cultured in vitro

    SciTech Connect

    Cully, D.E.; Gengenbach, B.G.; Smith, J.A.; Rubenstein, I.; Connely, J.A.; Park, W.D.

    1984-02-01

    This study was conducted to examine protein synthesis and L-(/sup 35/S)methionine incorporation into the endosperm of Zea mays L. kernels developing in vitro. Two-day-old kernels of the inbred line W64A were placed in culture on a defined medium containing 10 microCuries L-(/sup 35/S)methionine per milliliter (13 milliCuries per millimole) and harvested at 10, 15, 20, 25, 30, 35, and 40 days after pollination. Cultured kernels attained a final endosperm mass of 120 milligrams compared to 175 milligrams for field-grown controls. Field and cultured kernels had similar concentrations (microgram per milligram endosperm for total protein, albumin plus globulin, zein, and glutelin fractions at most kernel ages. Sodium, dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing patterns for endosperm proteins were similar for field and cultured kernels throughout development. By 15 days, over 70% of the L-(/sup 35/S)methionine taken up was present in endosperm proteins. Label incorporation visualized by fluorography generally followed the protein intensity of the stained gels. The high methionine content, low molecular weight zeins (i.e. 15 and 9 kilodaltons) were highly labeled. All of the radioactivity in hydrolyzed zein samples was recovered in the methionine peak indicating minimal conversion to L-(/sup 35/S)cysteine. The procedure described here is suitable for long term culture and labeling experiments in which continued kernel development is required.

  1. Endosperm Protein Synthesis and l-[35S]Methionine Incorporation in Maize Kernels Cultured In Vitro1

    PubMed Central

    Cully, David E.; Gengenbach, Burle G.; Smith, Jane A.; Rubenstein, Irwin; Connelly, James A.; Park, William D.

    1984-01-01

    This study was conducted to examine protein synthesis and l-[35S] methionine incorporation into the endosperm of Zea mays L. kernels developing in vitro. Two-day-old kernels of the inbred line W64A were placed in culture on a defined medium containing 10 microCuries l-[35S] methionine per milliliter (13 milliCuries per millimole) and harvested at 10, 15, 20, 25, 30, 35, and 40 days after pollination. Cultured kernels attained a final endosperm mass of 120 milligrams compared to 175 milligrams for field-grown controls. Field and cultured kernels had similar concentrations (microgram per milligram endospern) for total protein, albumin plus globulin, zein, and glutelin fractions at most kernel ages. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing patterns for endosperm proteins were similar for field and cultured kernels throughout development. By 15 days, over 70% of the l-[35S]methionine taken up was present in endosperm proteins. Label incorporation visualized by fluorography generally followed the protein intensity of the stained gels. The high methionine content, low molecular weight zeins (i.e. 15 and 9 kilodaltons) were highly labeled. All of the radioactivity in hydrolyzed zein samples was recovered in the methionine peak indicating minimal conversion to l-[35S]cysteine. The procedure described here is suitable for long term culture and labeling experiments in which continued kernel development is required. Images Fig. 2 Fig. 3 Fig. 4 PMID:16663428

  2. Pleural tissue repair with cord blood platelet gel

    PubMed Central

    Rosso, Lorenzo; Parazzi, Valentina; Damarco, Francesco; Righi, Ilaria; Santambrogio, Luigi; Rebulla, Paolo; Gatti, Stefano; Ferrero, Stefano; Nosotti, Mario; Lazzari, Lorenza

    2014-01-01

    Background Prolonged air leak is the major cause of morbidity after pulmonary resection. In this study we used in vitro and in vivo experiments to investigate an innovative approach based on the use of human umbilical cord blood platelet gel. Materials and methods In vitro, a scratch assay was performed to test the tissue repair capability mediated by cord blood platelet gel compared to the standard culture conditions using human primary mesothelial cells. In vivo, an iatrogenic injury was made to the left lung of 54 Wistar rats. Cord blood platelet gel was placed on the injured area only in treated animals and at different times histological changes and the presence of pleural adhesions were evaluated. In addition, changes in the pattern of soluble inflammatory factors were investigated using a multiplex proteome array. Results In vitro, mesothelial cell damage was repaired in a shorter time by cord blood platelet gel than in the control condition (24 versus 35 hours, respectively). In vivo, formation of new mesothelial tissue and complete tissue recovery were observed at 45±1 and 75±1 hours in treated animals and at 130±2.5 and 160±6 hours in controls, respectively. Pleural adhesions were evident in 43% of treated animals compared to 17% of controls. No complications were observed. Interestingly, some crucial soluble factors involved in inflammation were significantly reduced in treated animals. Discussion Cord blood platelet gel accelerates the repair of pleural damage and stimulates the development of pleural adhesions. Both properties could be particularly useful in the management of prolonged air leak, and to reduce inflammation. PMID:23736928

  3. Colloidal gel and its application in tissue engineering

    NASA Astrophysics Data System (ADS)

    Xie, Baojun

    2005-12-01

    Scope and method of study. Three dimensional, porous polymer scaffolds are fabricated by direct writing of colloidal gels. This work focuses on both the processing of colloidal gel and assembly of the scaffold structures as well as characterization of cytotoxicity and protein release kinetics. Specifically, rheological and elastic properties of the colloidal gels are probed as a function of solids loading and binder concentration. Porous scaffolds are characterized by optical and electron microscopy. In vitro studies include cell mortality after six weeks culture on passive scaffolds, model protein release profiles from scaffolds, and quantitative measurement of protein activity upon release from the scaffolds by chemotaxis. Findings and conclusions. The polymer colloidal gels formulated with acrylic latex particles and Pluronic F127 copolymer binder have pseudoplastic with yield stress rheology. Increases in solids loading and Pluronic concentration cause increased viscosity, elastic modulus, and yield stress. The rheology and rapid recovery of yield allow for flow through a deposition nozzle of the direct write toot and rapid setting of the extrudate to maintain the deposited structure. Scaffolds with a wide variety of porosity are fabricated. Because of the aqueous and low temperature nature of the process, bioactive molecules such as proteins are readily incorporated into the scaffold either in their original form or encapsulated in chitosan nanoparticles and subsequently released without denaturation and in a controlled fashion. Protein release rate is dependent on both the degree of coalescence of the scaffold material and the molecular weight of the chitosan nanoparticles. Protein inclusion and subsequent release is demonstrated using BSA and PDGF-BB. The scaffolds fabricated are non-cytotoxic as confirmed by QEC6 cell culture. Heterogeneous scaffolds with localized regions of dissolved species are demonstrated to illustrate the capability to assembly

  4. Microbial Community Structure of Korean Cabbage Kimchi and Ingredients with Denaturing Gradient Gel Electrophoresis.

    PubMed

    Hong, Sung Wook; Choi, Yun-Jeong; Lee, Hae-Won; Yang, Ji-Hee; Lee, Mi-Ai

    2016-06-28

    Kimchi is a traditional Korean fermented vegetable food, the production of which involves brining of Korean cabbage, blending with various other ingredients (red pepper powder, garlic, ginger, salt-pickled seafood, etc.), and fermentation. Recently, kimchi has also become popular in the Western world because of its unique taste and beneficial properties such as antioxidant and antimutagenic activities, which are derived from the various raw materials and secondary metabolites of the fermentative microorganisms used during production. Despite these useful activities, analysis of the microbial community present in kimchi has received relatively little attention. The objective of this study was to evaluate the bacterial community structure from the raw materials, additives, and final kimchi product using the culture-independent method. Specifically, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was used to analyze the 16S rRNA partial sequences of the microflora. One primer set for bacteria, 341F(GC)-518R, reliably produced amplicons from kimchi and its raw materials, and these bands were clearly separated on a 35-65% denaturing gradient gel. Overall, 117 16S rRNA fragments were identified by PCR-DGGE analysis. Pediococcus pentosaceus, Leuconostoc citreum, Leuconostoc gelidum, and Leuconostoc mesenteroides were the dominant bacteria in kimchi. The other strains identified were Tetragenococcus, Pseudomonas, Weissella, and uncultured bacterium. Comprehensive analysis of these microorganisms could provide a more detailed understanding of the biologically active components of kimchi and help improve its quality. PCR-DGGE analysis can be successfully applied to a fermented food to detect unculturable or other species. PMID:26907755

  5. Metal-silica sol-gel materials

    NASA Technical Reports Server (NTRS)

    Stiegman, Albert E. (Inventor)

    2002-01-01

    The present invention relates to a single phase metal-silica sol-gel glass formed by the co-condensation of a transition metal with silicon atoms where the metal atoms are uniformly distributed within the sol-gel glass as individual metal centers. Any transition metal may be used in the sol-gel glasses. The present invention also relates to sensor materials where the sensor material is formed using the single phase metal-silica sol-gel glasses. The sensor materials may be in the form of a thin film or may be attached to an optical fiber. The present invention also relates to a method of sensing chemicals using the chemical sensors by monitoring the chromatic change of the metal-silica sol-gel glass when the chemical binds to the sensor. The present invention also relates to oxidation catalysts where a metal-silica sol-gel glass catalyzes the reaction. The present invention also relates to a method of performing oxidation reactions using the metal-silica sol-gel glasses. The present invention also relates to organopolymer metal-silica sol-gel composites where the pores of the metal-silica sol-gel glasses are filled with an organic polymer polymerized by the sol-gel glass.

  6. User`s guide and documentation manual for ``PC-Gel`` simulator

    SciTech Connect

    Chang, Ming-Ming; Gao, Hong W.

    1993-10-01

    PC-GEL is a three-dimensional, three-phase (oil, water, and gas) permeability modification simulator developed by incorporating an in-situ gelation model into a black oil simulator (BOAST) for personal computer application. The features included in the simulator are: transport of each chemical species of the polymer/crosslinker system in porous media, gelation reaction kinetics of the polymer with crosslinking agents, rheology of the polymer and gel, inaccessible pore volume to macromolecules, adsorption of chemical species on rock surfaces, retention of gel on the rock matrix, and permeability reduction caused by the adsorption of polymer and gel. The in-situ gelation model and simulator were validated against data reported in the literature. The simulator PC-GEL is useful for simulating and optimizing any combination of primary production, waterflooding, polymer flooding, and permeability modification treatments. A general background of permeability modification using crosslinked polymer gels is given in Section I and the governing equations, mechanisms, and numerical solutions of PC-GEL are given in Section II. Steps for preparing an input data file with reservoir and gel-chemical transport data, and recurrent data are described in Sections III and IV, respectively. Example data inputs are enclosed after explanations of each input line to help the user prepare data files. Major items of the output files are reviewed in Section V. Finally, three sample problems for running PC-GEL are described in Section VI, and input files and part of the output files of these problems are listed in the appendices. For the user`s reference a copy of the source code of PC-GEL computer program is attached in Appendix A.

  7. Optical-CT gel-dosimetry I: basic investigations.

    PubMed

    Oldham, Mark; Siewerdsen, Jeffrey H; Kumar, Sai; Wong, John; Jaffray, David A

    2003-04-01

    Comprehensive verification of the intricate dose distributions associated with advanced radiation treatments is now an immediate and substantial problem. The task is challenging using traditional dosimeters because of restrictions to point measurements (ion chambers, diodes, TLD, etc.) or planar measurements (film). In essence, rapid advances in the technology to deliver radiation treatments have not been paralleled by corresponding advances in the ability to verify these treatments. A potential solution has emerged in the form of water equivalent three dimensional (3D) gel-dosimetry. In this paper we present basic characterization and performance studies of a prototype optical-CT scanning system developed in our laboratory. An analysis of the potential role or scope of gel dosimetry, in relation to other dosimeters, and to verification across the spectrum of therapeutic techniques is also given. The characterization studies enabled the determination of nominal operating conditions for optical-CT scanning. "Finger" phantoms are introduced as a powerful and flexible tool for the investigation of optical-CT performance. The modulation-transfer function (MTF) of the system is determined to be better than 10% out to 1 mm(-1), confirming sub-mm imaging ability. System performance is demonstrated by the acquisition of a 1 x 1 x 1 mm3 dataset through the dose distribution delivered by an x-ray lens that focuses x rays in the energy range 40-80 KeV. This 3D measurement would be extremely difficult to achieve with other dosimetry techniques and highlights some of the strengths of gel dosimetry. Finally, an optical Monte Carlo model is introduced and shown to have potential to model light transport through gel-dosimetry systems, and to provide a tool for the study and optimization of optical-CT gel dosimetry. The model utilizes Mie scattering theory and requires knowledge of the variation of the particle size distribution with dose. The latter was determined here using the

  8. Selective gel system for permeability profile control

    SciTech Connect

    Shu, P.

    1990-10-16

    This patent describes a selective gel for closing pores in a more permeable zone of a formation. It comprises: an aqueous solution of a first composition sufficient to form ex-situ a size selective, shear thinning first gel which comprises a xanthan biopolymer, and a transitional metal ion; and an aqueous solution of a second composition sufficient to form thermally a second in-situ gel that which comprises and aldehyde, and a phenolic compound which solutions are combined and allowed to form a shearable, rehealable ex-situ gel which can be injected into the permeable zone where it reheals when heated by the formation and thereafter forms a solid gel substantially more resistant to formation conditions than the first gel.

  9. Automated apparatus for producing gradient gels

    DOEpatents

    Anderson, Norman L.

    1986-01-01

    Apparatus for producing a gradient gel which serves as a standard medium for a two-dimensional analysis of proteins, the gel having a density gradient along its height formed by a variation in gel composition, with the apparatus including first and second pumping means each including a plurality of pumps on a common shaft and driven by a stepping motor capable of providing small incremental changes in pump outputs for the gel ingredients, the motors being controlled, by digital signals from a digital computer, a hollow form or cassette for receiving the gel composition, means for transferring the gel composition including a filler tube extending near the bottom of the cassette, adjustable horizontal and vertical arms for automatically removing and relocating the filler tube in the next cassette, and a digital computer programmed to automatically control the stepping motors, arm movements, and associated sensing operations involving the filling operation.

  10. Automated apparatus for producing gradient gels

    DOEpatents

    Anderson, N.L.

    1983-11-10

    Apparatus for producing a gradient gel which serves as a standard medium for a two-dimensional analysis of proteins, the gel having a density gradient along its height formed by a variation in gel composition, with the apparatus including first and second pumping means each including a plurality of pumps on a common shaft and driven by a stepping motor capable of providing small incremental changes in pump outputs for the gel ingredients, the motors being controlled, by digital signals from a digital computer, a hollow form or cassette for receiving the gel composition, means for transferring the gel composition including a filler tube extending near the bottom of the cassette, adjustable horizontal and vertical arms for automatically removing and relocating the filler tube in the next cassette, and a digital computer programmed to automatically control the stepping motors, arm movements, and associated sensing operations involving the filling operation.