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Sample records for agarose gel retardation

  1. Recycling of superfine resolution agarose gel.

    PubMed

    Seng, T-Y; Singh, R; Faridah, Q Z; Tan, S-G; Alwee, S S R S

    2013-01-01

    Genetic markers are now routinely used in a wide range of applications, from forensic DNA analysis to marker-assisted plant and animal breeding. The usual practice in such work is to extract the DNA, prime the markers of interest, and sift them out by electrically driving them through an appropriate matrix, usually a gel. The gels, made from polyacrylamide or agarose, are of high cost, limiting their greater applications in molecular marker work, especially in developing countries where such technology has great potential. Trials using superfine resolution (SFR) agarose for SSR marker screening showed that it is capable of resolving SSR loci and can be reused up to 14 times, thus greatly reducing the cost of each gel run. Furthermore, for certain applications, low concentrations of agarose sufficed and switching to lithium borate buffer, instead of the conventional Tris-borate-ethylenediaminetetraacetic acid buffer, will further save time and cost. The 2.5% gel was prepared following the Agarose SFR(TM) manual by adding 2.5 g agarose powder into 100 mL 1X lithium borate buffer in a 250-mL flask with rapid stirring. Two midigels (105 x 83 mm, 17 wells) or 4 minigels (50 x 83 mm, 8 wells), 4 mm thickness can be prepared from 100 mL gel solution. A total of 1680 PCR products amplified using 140 SSR markers from oil palm DNA samples were tested in this study using SFR recycled gel. As average, the gel can be recycled 8 times with good resolution, but can be recycled up to 14 times before the resolutions get blurred. PMID:23546970

  2. The trajectories of spheres during agarose gel electrophoresis.

    PubMed

    Griess, G A; Harris, R A; Serwer, P

    1993-01-01

    To develop a physical description of the gel-induced retardation of spheres during gel electrophoresis, the microscopic motion of single electrically charged latex spheres is statistically quantified here, by digital image analysis. To obtain adequate resolution in space, comparatively large spheres, 240 nm in radius, are used. The following observations are made during electrophoresis in a 0.2% agarose gel at 22 degrees C: (a) When a comparatively high field (3.0 V cm-1) is used, inelastic collisions result in field-induced trapping of spheres; no elastic collisions are observed. (b) Reduction of the field from 3.0 to 0.0 V cm-1 results in reverse migration of previously trapped spheres. (c) In the absence of trapping, the electrical field does not cause an alteration in the tortuosity of motion (i.e. motion in a field-perpendicular direction). (d) When results are obtained for a constant time between images (0.2 s), gel-dependent deviations from a true random walk are not observed in the absence of trapping. (e) When results are obtained as a function of time between images, significant gel-dependent deviation from a random walk is observed. In the absence of trapping, the data presented here indicate that retardation is derived primarily from dissipative processes that are concentrated near gel fibers. However, steric effects have not yet been distinguished from hydrodynamic effects. PMID:8199223

  3. Orientation of DNA in agarose gels.

    PubMed Central

    Borejdo, J

    1989-01-01

    An orientation of the lambda DNA during the electrophoresis in agarose gels was measured by a microscopic linear dichroism technique. The method involved staining the DNA with the dye ethidium bromide and measuring under the microscope the polarization properties of the fluorescence field around the electrophoretic band containing the nucleic acid. It was first established that the fluorescence properties of the ethidium bromide-DNA complex were the same in agarose gel and in a solution. Then the linear dichroism method was used to measure the dichroism of the absorption dipole of EB dye bound to lambda DNA. In a typical experiment the orientation of two-tenth of a picogram (2 x 10(-13)g) of DNA was measured. When the electric field was turned on, the dichroism developed rapidly and assumed a steady state value which increased with the strength of the field and with the size of DNA. A linear dichroism equation related the measured dichroism of fluorescence to the mean orientation of the absorption dipole of ethidium bromide and to an extent to which the orientation of this dipole deviated from the mean. The observed development of dichroism in the presence of an electric field was interpreted as an alignment of DNA along the direction of the field. The increase in the steady state value of dichroism with the rise in the strength of the field and with the increase of the size of DNA was interpreted as a better alignment of DNA along the direction of the field and as a smaller deviation from its mean orientation. Images FIGURE 8 PMID:2527571

  4. Transverse agarose pore gradient gel electrophoresis of DNA.

    PubMed

    Fawcett, J S; Wheeler, D; Chrambach, A

    1992-06-01

    Transverse agarose pore gradient gels were prepared on GelBond in the concentration range of nominally 0.2-1.5% SeaKem GTG agarose, using density stabilization by glycerol and incorporation of a dye to define the gel concentration at each point on the pore gradient gel. The distribution of the dye was evaluated by photography, video-acquisition and digitization of the gradient mixture and by densitometry of the gel. The gel was applied to the electrophoresis of a 1-kb standard ladder of DNA fragments, using standard submarine apparatus. The method extends to agarose gel electrophoresis the benefits of semi-automated analysis of 'Ferguson curves' described in application to polyacrylamide gel by Wheeler et al. (J. Biochem. Biophys. Methods 24, 171-180). PMID:1640052

  5. Blinking suppression of single quantum dots in agarose gel

    SciTech Connect

    Ko, H. C.; Yuan, C. T.; Tang, Jau; Lin, S. H.

    2010-01-04

    Fluorescence blinking is commonly observed in single molecule/particle spectroscopy, but it is an undesirable feature in many applications. We demonstrated that single CdSe/ZnS quantum dots in agarose gel exhibited suppressed blinking behavior. In addition, the long-time exponential bending tail of the power-law blinking statistics was found to be influenced by agarose gel concentration. We suggest that electron transfer from the light state to the dark state might be blocked due to electrostatic surrounding of gel with inherent negatively charged fibers.

  6. Effect of sugars and polyols on water in agarose gels.

    PubMed

    Nishinari, K; Watase, M; Williams, P A; Phillips, G O

    1991-01-01

    Effects of ribose, glucose, sucrose, ethylene glycol, glycerin, propylene glycol, and sorbitol on water in concentrated agarose gels were studied by differential scanning calorimetry at low temperatures. Changes in the phase transition temperatures of 40% agarose gels, induced by the addition of these chemical reagents, are discussed, together with rheological and thermal data for the same systems at ambient and higher temperatures. Both sugars and polyols are believed to reduce the amount of freezable water and to promote plasticization and molecular mobility of agarose chains in gels, thus shifting the glass transition temperatures to lower temperatures. However, the effects of decreasing freezable water, and the direct effect on the junction zones, produced by sugars seem to be different from the effects produced by polyols. PMID:1746332

  7. 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

  8. 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

  9. 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.

  10. Electrophoresis and orientation of F-actin in agarose gels.

    PubMed Central

    Borejdo, J; Ortega, H

    1989-01-01

    F-Actin was electrophoresed on agarose gels. In the presence of 2 mM MgCl2 and above pH 8.5 F-actin entered 1% agarose; when the electric field was 2.1 V/cm and the pH was 8.8, F-actin migrated through a gel as a single band at a rate of 2.5 mm/h. Labeling of actin with fluorophores did not affect its rate of migration, but an increase in ionic strength slowed it down. After the electrophoresis actin was able to bind phalloidin and heavy meromyosin (HMM) and it activated Mg2+-dependent ATPase activity of HMM. The mobility of F-actin increased with the rise in pH. Acto-S-1 complex was also able to migrate in agarose at basic pH, but at a lower rate than F-actin alone. The orientation of fluorescein labeled F-actin and of fluorescein labeled S-1 which formed rigor bonds with F-actin was measured during the electrophoresis by the fluorescence detected linear dichroism method. The former showed little orientation, probably because the dye was mobile on the surface of actin, but we were able to measure the orientation of the absorption dipole of the dye bound to S-1 which was attached to F-actin, and found that it assumed an orientation largely parallel to the direction of the electric field. These results show that actin can migrate in agarose gels in the F form and that it is oriented during the electrophoresis. Images FIGURE 1 FIGURE 3 FIGURE 4 PMID:2528384

  11. Separations of Short DNA in Agarose Gels: What Model Applies?

    NASA Astrophysics Data System (ADS)

    Beheshti, Afshin

    2000-03-01

    Gel Electrophoresis is used ubiquitously for separating proteins and DNA fragments from mixtures into individual components. Molecules separate because their mobilities, μ = v / E, depend on their effective charge and effective friction imposed by the gel. Models describing the dependence of μ on molecular parameters are inadequate. For example, the reptation theory as applied in other studies suggests μ proportional to (1/L). We asked whether the relationship (1/μ) proportional to AL + B, where A and B are independent parameters, would better describe electrophoretic separations of DNA fragments over a wide range of fragment lengths. A series of DNA ladders were electrophoresed in Seakem and in Metaphor agarose and mobilities studied as a function of their DNA length. In the Metaphor agarose a range of 10 bp to 1500 bp DNA fragments were observed. While in the Seakem agarose the study was done with DNA fragments ranging from 100 bp to 10 kbp. Results of the fits for μ vs. L indicate the dependence is more complex than these simple models suggest. Supported by NSF BES 9521381 and NSF Research Training Grant Fellowship 130362022.

  12. Cloning of DNA fragments: ligation reactions in agarose gel.

    PubMed

    Furtado, Agnelo

    2014-01-01

    Ligation reactions to ligate a desired DNA fragment into a vector can be challenging to beginners and especially if the amount of the insert is limiting. Although additives known as crowding agents, such as PEG 8000, added to the ligation mixes can increase the success one has with ligation reactions, in practice the amount of insert used in the ligation can determine the success or the failure of the ligation reaction. The method described here, which uses insert DNA in gel slice added directly into the ligation reaction, has two benefits: (a) using agarose as the crowding agent and (b) reducing steps of insert purification. The use of rapid ligation buffer and incubation of the ligation reaction at room temperature greatly increase the efficiency of the ligation reaction even for blunt-ended ligation. PMID:24243199

  13. Electrophoresis for genotyping: microtiter array diagonal gel electrophoresis on horizontal polyacrylamide gels, hydrolink, or agarose.

    PubMed

    Day, I N; Humphries, S E

    1994-11-01

    Electrophoresis of DNA has been performed traditionally in either an agarose or acrylamide gel matrix. Considerable effort has been directed to improved quality agaroses capable of high resolution, but for small fragments, such as those from polymerase chain reaction (PCR) and post-PCR digests, acrylamide still offers the highest resolution. Although agarose gels can easily be prepared in an open-faced format to gain the conveniences of horizontal electrophoresis, acrylamide does not polymerize in the presence of air and the usual configurations for gel preparation lead to electrophoresis in the vertical dimension. We describe here a very simple device and method to prepare and manipulate horizontal polyacrylamide gels (H-PAGE). In addition, the open-faced horizontal arrangement enables loading of arrays of wells. Since many procedures are undertaken in standard 96-well microtiter plates, we have also designed a device which preserves the exact configuration of the 8 x 12 array and enables electrophoresis in tracks following a 71.6 degrees diagonal between wells (MADGE, microtiter array diagonal gel electrophoresis), using either acrylamide or agarose. This eliminates almost all of the staff time taken in setup, loading, and recordkeeping and offers high resolution for genotyping pattern recognition. The nature and size of the gels allow direct stacking of gels in one tank, so that a tank used typically to analyze 30-60 samples can readily be used to analyze 1000-2000 samples. The gels would also enable robotic loading. Electrophoresis allows analysis of size and charge, parameters inaccessible to liquid-phase methods: thus, genotyping size patterns, variable length repeats, and haplotypes is possible, as well as adaptability to typing of point variations using protocols which create a difference detectable by electrophoresis. PMID:7864363

  14. Rapid agarose gel electrophoretic mobility shift assay for quantitating protein: RNA interactions.

    PubMed

    Ream, Jennifer A; Lewis, L Kevin; Lewis, Karen A

    2016-10-15

    Interactions between proteins and nucleic acids are frequently analyzed using electrophoretic mobility shift assays (EMSAs). This technique separates bound protein:nucleic acid complexes from free nucleic acids by electrophoresis, most commonly using polyacrylamide gels. The current study utilizes recent advances in agarose gel electrophoresis technology to develop a new EMSA protocol that is simpler and faster than traditional polyacrylamide methods. Agarose gels are normally run at low voltages (∼10 V/cm) to minimize heating and gel artifacts. In this study we demonstrate that EMSAs performed using agarose gels can be run at high voltages (≥20 V/cm) with 0.5 × TB (Tris-borate) buffer, allowing for short run times while simultaneously yielding high band resolution. Several parameters affecting band and image quality were optimized for the procedure, including gel thickness, agarose percentage, and applied voltage. Association of the siRNA-binding protein p19 with its target RNA was investigated using the new system. The agarose gel and conventional polyacrylamide gel methods generated similar apparent binding constants in side-by-side experiments. A particular advantage of the new approach described here is that the short run times (5-10 min) reduce opportunities for dissociation of bound complexes, an important concern in non-equilibrium nucleic acid binding experiments. PMID:27495142

  15. Two methods that facilitate autoradiography of small /sup 32/P-labeled DNA fragments following electrophoresis in agarose gels

    SciTech Connect

    Cockerill, P.N.

    1988-02-01

    Two methods which permit detection by autoradiography of small /sup 32/P-labeled DNA fragments resolved by agarose gel electrophoresis are described. Agarose gel electrophoresis poses problems for autoradiography as (i) the gels are normally too thick to allow autoradiography without being dried first, and (ii) fragments of DNA of 1000 bp or less in length are readily lost during drying. In this study DNA fragments as small as 121 bp have been retained in agarose gels upon drying. This has been achieved by either (i) first fixing the DNA with the cationic detergent cetyltrimethylammonium bromide, or (ii) drying the agarose gels onto Zeta-Probe charge-modified membranes.

  16. Solvent-impregnated agarose gel liquid phase microextraction of polycyclic aromatic hydrocarbons in water.

    PubMed

    Loh, Saw Hong; Sanagi, Mohd Marsin; Wan Ibrahim, Wan Aini; Hasan, Mohamed Noor

    2013-08-01

    A new microextraction procedure termed agarose gel liquid phase microextraction (AG-LPME) combined with gas chromatography-mass spectrometry (GC-MS) was developed for the determination of selected polycyclic aromatic hydrocarbons (PAHs) in water. The technique utilized an agarose gel disc impregnated with the acceptor phase (1-octanol). The extraction procedure was performed by allowing the solvent-impregnated agarose gel disc to tumble freely in the stirred sample solution. After extraction, the agarose gel disc was removed and subjected to centrifugation to disrupt its framework and to release the impregnated solvent, which was subsequently withdrawn and injected into the GC-MS for analysis. Under optimized extraction conditions, the new method offered high enrichment factors (89-177), trace level LODs (9-14ngL(-1)) and efficient extraction with good relative recoveries in the range of 93.3-108.2% for spiked drinking water samples. AG-LPME did not exhibit any problems related to solvent dissolution, and it provided high extraction efficiencies that were comparable to those of hollow fiber liquid phase microextraction (HF-LPME) and significantly higher than those of agarose film liquid phase microextraction (AF-LPME). This technique employed a microextraction format and utilized an environmentally compatible solvent holder that supported the green chemistry concept. PMID:23809804

  17. Molecular stretching of long DNA in agarose gel using alternating current electric fields.

    PubMed Central

    Kaji, Noritada; Ueda, Masanori; Baba, Yoshinobu

    2002-01-01

    We demonstrate a novel method for stretching a long DNA molecule in agarose gel with alternating current (AC) electric fields. The molecular motion of a long DNA (T4 DNA; 165.6 kb) in agarose gel was studied using fluorescence microscopy. The effects of a wide range of field frequencies, field strengths, and gel concentrations were investigated. Stretching was only observed in the AC field when a frequency of approximately 10 Hz was used. The maximal length of the stretched DNA had the longest value when a field strength of 200 to 400 V/cm was used. Stretching was not sensitive to a range of agarose gel concentrations from 0.5 to 3%. Together, these experiments indicate that the optimal conditions for stretching long DNA in an AC electric field are a frequency of 10 Hz with a field strength of 200 V/cm and a gel concentration of 1% agarose. Using these conditions, we were able to successfully stretch Saccharomyces cerevisiae chromosomal DNA molecules (225-2,200 kb). These results may aid in the development of a novel method to stretch much longer DNA, such as human chromosomal DNA, and may contribute to the analysis of a single chromosomal DNA from a single cell. PMID:11751320

  18. High-Yield Separation of Metallic and Semiconducting Single-Wall Carbon Nanotubes by Agarose Gel Electrophoresis

    NASA Astrophysics Data System (ADS)

    Tanaka, Takeshi; Jin, Hehua; Miyata, Yasumitsu; Kataura, Hiromichi

    2008-11-01

    We have developed a novel separation method of metallic and semiconducting single-wall carbon nanotubes (SWCNTs) using agarose gel electrophoresis. When the SWCNTs were isolated with sodium dodecyl sulfate (SDS) and embedded in agarose gel, only the metallic SWCNTs separated from the starting gel by an electric field. After 20 min, almost all SWCNTs applied to gel electrophoresis were separated into two fractions, containing ˜95% semiconducting and ˜70% metallic nanotubes. The difference in the response to the electric field between metallic and semiconducting SWCNTs can be explained by the higher affinity of semiconducting SWCNTs to agarose than to SDS.

  19. Pulsatile dynamic stiffness of cartilage-like materials and use of agarose gels to validate mechanical methods and models.

    PubMed

    Scandiucci de Freitas, P; Wirz, D; Stolz, M; Göpfert, B; Friederich, N-F; Daniels, A U

    2006-08-01

    Stiffness is a fundamental indicator of the functional state of articular cartilage. Reported test modes include compressive incremental strain to determine the equilibrium modulus, and sinusoidal strain to determine the dynamic modulus and stress/strain loss angle. Here, initial development is described for a method recognizing that gait is pulsatile. Agarose gels have been used by others for validation or comparison of mechanical test methods and models for cartilage and proteoglycan aggregate. Accordingly, gels ranging from 0.5 to 20% agarose were prepared. Pulsatile stiffness in both indentation and unconfined compression were closely reproducible. Stiffness as a function of agarose concentration rose exponentially, as found using other methods. Indentation stiffness was higher than for unconfined compression and ranged from approximately 2.0 kPa for 0.5% gel to approximately 3,800 kPa for 20% gel. Pulsatile dynamic stiffness appears to be a useful method, although further development is needed. Agarose gel stiffness values obtained by other methods were reviewed for comparison. Unfortunately, reported values for a given agarose concentration ranged widely (e.g. fourfold) even when test methods were similar. Causes appear to include differences in molecular weight and gel preparation time-temperature regimens. Also, agarose is hygroscopic, leading to unintended variations in gel composition. Agarose gels are problematic materials for validation or comparison of cartilage mechanical test methods and models. PMID:16470817

  20. DNA electrophoresis in agarose gels: A new mobility vs. DNA length dependence

    NASA Astrophysics Data System (ADS)

    Beheshti, Afshin

    2002-04-01

    Separations were performed on double stranded DNA (dsDNA) using electrophoresis. Electrophoresis is the steady transport of particles under the influence of an external electric field. Double stranded DNA fragments ranging in length from 200 base pairs (bp) to 194,000 bp (0.34 nm = 1 bp) were electrophoresed at agarose gel concentrations T = 0.4%--1.5%. The electric field was varied from 0.62 V/cm to 6.21 V/cm. A wide range of electric fields and gel concentrations were used to study the usefulness of a new interpolation equation, 1mL =1mL-( 1mL-1 ms)e-L/g , where mL,ms , and g are independent free fitting parameters. The long length mobility limit is interpreted as mL , the short length mobility limit is ms , and g is the crossover between the long length limit and the short length limit. This exponential relation fit very well (chi2 ≥ 0.999) when there are two smooth transitions observed in the "reptation plots" (plotting 3mL/m∘ vs. L) (J. Rousseau, G. Drouin, and G. W. Slater, Phys Rev Lett. 1997, 79, 1945--1948). Fits deviate from the data when three different slopes were observed in the reptation plots. Reptation plots were used to determine a phase diagram for dsDNA migration regimes. The phase diagrams define different regions where mechanisms for molecular transport affect the migration of dsDNA in agarose gels during electrophoresis. The parameters from the equation have also been interpreted to provide a physical description of the structure of the agarose gel by calculating the pore sizes. The relations between the values for the pore sizes and the phase diagrams are interpreted to better understand the migration of the DNA through agarose gels.

  1. Interactive forces between sodium dodecyl sulfate-suspended single-walled carbon nanotubes and agarose gels.

    PubMed

    Clar, Justin G; Silvera Batista, Carlos A; Youn, Sejin; Bonzongo, Jean-Claude J; Ziegler, Kirk J

    2013-11-27

    Selective adsorption onto agarose gels has become a powerful method to separate single-walled carbon nanotubes (SWCNTs). A better understanding of the nature of the interactive forces and specific sites responsible for adsorption should lead to significant improvements in the selectivity and yield of these separations. A combination of nonequilibrium and equilibrium studies are conducted to explore the potential role that van der Waals, ionic, hydrophobic, π-π, and ion-dipole interactions have on the selective adsorption between agarose and SWCNTs suspended with sodium dodecyl sulfate (SDS). The results demonstrate that any modification to the agarose gel surface and, consequently, the permanent dipole moments of agarose drastically reduces the retention of SWCNTs. Because these permanent dipoles are critical to retention and the fact that SDS-SWCNTs function as macro-ions, it is proposed that ion-dipole forces are the primary interaction responsible for adsorption. The selectivity of adsorption may be attributed to variations in polarizability between nanotube types, which create differences in both the structure and mobility of surfactant. These differences affect the enthalpy and entropy of adsorption, and both play an integral part in the selectivity of adsorption. The overall adsorption process shows a complex behavior that is not well represented by the Langmuir model; therefore, calorimetric data should be used to extract thermodynamic information. PMID:24164680

  2. Agarose gel tailored calcium carbonate nanoparticles-synthesis and biocompatibility evaluation.

    PubMed

    Biradar, Santoshkumar; Goornavar, Virupaxi; Periyakaruppan, Adaikkappan; Koehne, Jessica; Hall, Joseph C; Ramesh, Vani

    2014-06-01

    In this study, a novel approach to tailor the calcium carbonate nanoparticles was exploited based on agarose gel as polymer medium. The size of nanoparticles formed was governed by ionic diffusion and affected by weight percent of agarose and reaction temperature. The size, shape, purity, composition and allotropy of the synthesized nanoparticles were analyzed by different characterization techniques. Purity of nanoparticles as small as 37 nm demonstrates their suitability for broad range of industrial applications. The exposure of rat lung epithelial cells to these nanoparticles even at a higher concentration (50 microg/ml) did not induce considerable oxidative stress or cell death authenticating their fidelity to potential applications in the field of biotechnology and medicine. Through the simple and economic method of synthesis adopted in this study, separation of nanoparticles from the gel was easy, and process parameters could be optimized to control the particle size. PMID:24738380

  3. Agarose and Polyacrylamide Gel Electrophoresis Methods for Molecular Mass Analysis of 5–500 kDa Hyaluronan

    PubMed Central

    Bhilocha, Shardul; Amin, Ripal; Pandya, Monika; Yuan, Han; Tank, Mihir; LoBello, Jaclyn; Shytuhina, Anastasia; Wang, Wenlan; Wisniewski, Hans-Georg; de la Motte, Carol; Cowman, Mary K.

    2011-01-01

    Agarose and polyacrylamide gel electrophoresis systems for the molecular mass-dependent separation of hyaluronan (HA) in the size range of approximately 5–500 kDa have been investigated. For agarose-based systems, the suitability of different agarose types, agarose concentrations, and buffers systems were determined. Using chemoenzymatically synthesized HA standards of low polydispersity, the molecular mass range was determined for each gel composition, over which the relationship between HA mobility and logarithm of the molecular mass was linear. Excellent linear calibration was obtained for HA molecular mass as low as approximately 9 kDa in agarose gels. For higher resolution separation, and for extension to molecular masses as low as approximately 5 kDa, gradient polyacrylamide gels were superior. Densitometric scanning of stained gels allowed analysis of the range of molecular masses present in a sample, and calculation of weight-average and number-average values. The methods were validated for polydisperse HA samples with viscosity-average molecular masses of 112, 59, 37, and 22 kDa, at sample loads of 0.5 µg (for polyacrylamide) to 2.5 µg (for agarose). Use of the methods for electrophoretic mobility shift assays was demonstrated for binding of the HA-binding region of aggrecan (recombinant human aggrecan G1-IGD-G2 domains) to a 150 kDa HA standard. PMID:21684248

  4. Fractionation of SWNT/nucleic acid complexes by agarose gel electrophoresis

    NASA Astrophysics Data System (ADS)

    Vetcher, Alexandre A.; Srinivasan, Srimeenakshi; Vetcher, Ivan A.; Abramov, Semen M.; Kozlov, Mikhail; Baughman, Ray H.; Levene, Stephen D.

    2006-08-01

    We show that aqueous dispersions of single-walled carbon nanotubes (SWNTs), prepared with the aid of nucleic acids (NAs) such as RNA or DNA, can be separated into fractions using agarose gel electrophoresis. In a DC electric field, SWNT/NA complexes migrate in the gel in the direction of positive potential to form well-defined bands. Raman spectroscopy as a function of band position shows that nanotubes having different spectroscopic properties possess different electrophoretic mobilities. The migration patterns for SWNT/RNA and SWNT/DNA complexes differ. Parallel elution of the SWNT/NA complexes from the gel during electrophoresis and subsequent characterization by AFM reveals differences in nanotube diameter, length and curvature. The results suggest that fractionation of nanotubes can be achieved by this procedure. We discuss factors affecting the mobility of the nanotube complexes and propose analytical applications of this technique.

  5. Microneedle assisted micro-particle delivery from gene guns: experiments using skin-mimicking agarose gel.

    PubMed

    Zhang, Dongwei; Das, Diganta B; Rielly, Chris D

    2014-02-01

    A set of laboratory experiments has been carried out to determine if micro-needles (MNs) can enhance penetration depths of high-speed micro-particles delivered by a type of gene gun. The micro-particles were fired into a model target material, agarose gel, which was prepared to mimic the viscoelastic properties of porcine skin. The agarose gel was chosen as a model target as it can be prepared as a homogeneous and transparent medium with controllable and reproducible properties allowing accurate determination of penetration depths. Insertions of various MNs into gels have been analysed to show that the length of the holes increases with an increase in the agarose concentration. The penetration depths of micro-particle were analysed in relation to a number of variables, namely the operating pressure, the particle size, the size of a mesh used for particle separation and the MN dimensions. The results suggest that the penetration depths increase with an increase of the mesh pore size, because of the passage of large agglomerates. As these particles seem to damage the target surface, then smaller mesh sizes are recommended; here, a mesh with a pore size of 178 μm was used for the majority of the experiments. The operating pressure provides a positive effect on the penetration depth, that is it increases as pressure is increased. Further, as expected, an application of MNs maximises the micro-particle penetration depth. The maximum penetration depth is found to increase as the lengths of the MNs increase, for example it is found to be 1272 ± 42, 1009 ± 49 and 656 ± 85 μm at 4.5 bar pressure for spherical micro-particles of 18 ± 7 μm diameter when we used MNs of 1500, 1200 and 750 μm length, respectively. PMID:24399616

  6. Quantitation of pyrimidine dimer contents of nonradioactive deoxyribonucleic acid by electrophoresis in alkaline agarose gels

    SciTech Connect

    Sutherland, B.M.; Shih, A.G.

    1983-02-15

    We have developed a method of quantitating the pyrimidine dimer content of nonradioactive DNAs. DNA samples are treated with the UV-endonuclease from Micrococcus luteus and then separated according to molecular weight by electrophoresis on alkaline agarose gels. From their migration relative to known molecular weight standards, their median molecular weight and thus the number of dimers per DNA molecule in each sample can be calculated. Results of action spectra for dimer formation in T7 bacteriophage measured by this method agree well with action spectra for T7 killing. In addition, the method gives dimer yields in good agreement with those obtained by others using alkaline sucrose gradient sedimentation.

  7. A New Organic Dye-Based Staining for The Detection of Plant DNA in Agarose Gels.

    PubMed

    Sönmezoğlu, Özlem Ateş; Özkay, Kerime

    2015-01-01

    Ethidium bromide (EtBr) is used to stain DNA in agarose gel electrophoresis, but this dye is mutagenic and carcinogenic. We investigated N-719, which is a visible, reliable and organic Ruthenium-based dye, and five fluorescent alternatives for staining plant DNA. For prestaining and poststaining, N-719, GelRed, and SYBR Safe stained both DNA and PCR product bands as clearly as EtBr. SYBR Green I, methylene blue, and crystal violet were effective for poststaining only. The organic dye N-719 stained DNA bands as sensitively and as clearly as EtBr. Consequently, organic dyes can be used as alternatives to EtBr in plant biotechnology studies. PMID:26158569

  8. Image-guided Convection-enhanced Delivery into Agarose Gel Models of the Brain

    PubMed Central

    Sillay, Karl A.; McClatchy, S. Gray; Shepherd, Brandon A.; Venable, Garrett T.; Fuehrer, Tyler S.

    2014-01-01

    Convection-enhanced delivery (CED) has been proposed as a treatment option for a wide range of neurological diseases. Neuroinfusion catheter CED allows for positive pressure bulk flow to deliver greater quantities of therapeutics to an intracranial target than traditional drug delivery methods. The clinical utility of real time MRI guided CED (rCED) lies in the ability to accurately target, monitor therapy, and identify complications. With training, rCED is efficient and complications may be minimized. The agarose gel model of the brain provides an accessible tool for CED testing, research, and training. Simulated brain rCED allows practice of the mock surgery while also providing visual feedback of the infusion. Analysis of infusion allows for calculation of the distribution fraction (Vd/Vi) allowing the trainee to verify the similarity of the model as compared to human brain tissue. This article describes our agarose gel brain phantom and outlines important metrics during a CED infusion and analysis protocols while addressing common pitfalls faced during CED infusion for the treatment of neurological disease. PMID:24894268

  9. Detection of genotoxic insult as DNA strand breaks in fish blood cells by agarose gel electrophoresis

    SciTech Connect

    Theodorakis, C.W. ); D'Surney, S.J. . Dept. of Biology); Shugart, L.R. . Environmental Sciences Division)

    1994-07-01

    DNA, isolated from the blood cells of bluegill sunfish (Lepomis macrochirus) exposed in the lab to bedded sediment collected from a site contaminated with genotoxic compounds (i.e., PAHs, PCBs, and heavy metals), was examined for strand breakage by agarose gel electrophoresis. Before electrophoresis the blood cells were embedded in agarose plugs and incubated with proteinase. After electrophoresis under both neutral (pH 7) or alkaline (pH 12) conditions, the median molecular length (MML) of the DNA distributed in the gel was determined. These quantitative measures were used to estimate the difference in the number of double- and single-strand breaks between DNA preparations. Both types of strand breakage were found to be greater in fish exposed to sediment contaminated with genotoxic compounds as compared to nonexposed fish. A statistically significant correlation was demonstrated between the MML value obtained by the electrophoretic assay reported here and the F value (measure of DNA double-strandedness) obtained by the alkaline unwinding assay.

  10. Growth and surface-enhanced Raman scattering of Ag nanoparticle assembly in agarose gel

    NASA Astrophysics Data System (ADS)

    Keating, M.; Chen, Y.; Larmour, I. A.; Faulds, K.; Graham, D.

    2012-08-01

    Agarose gel loaded with silver nanoparticles has attracted a lot of attention recently due to its excellent molecular trapping capabilities and strong surface-enhanced Raman scattering (SERS). Despite its potential, the influence of the growth condition on the gel structure and resultant SERS intensity and reproducibility is not clear. In this work, we examine the effect of silver nitrate feed solution concentration, the precursor to neutral silver nanoparticles, on the resultant nanoparticle morphology, gel homogeneity, SERS signal intensity and reproducibility. SERS of trans-1,2-bis-(4-pyridyl) ethylene, a non-resonant molecule, was conducted. A substantial rise in SERS signal strength with increasing feed concentration was observed, accompanied by a modest increase in average particle size as disclosed by TEM analysis. At higher concentrations, gels possessed larger particles from broader size distributions which had a higher tendency to aggregate. This created a higher density of SERS ‘hotspots’, regions of intense electromagnetic field crucial for maximal enhancement of the Raman signal, but also led to increased spot-to-spot signal variation due to a marked change in nanoparticle morphology and gel homogeneity. Beyond an optimal feed concentration, no further increase in overall signal strength was evident, correlating with no appreciable rise in the number of larger particles.

  11. Detection of sequence variation in parasite ribosomal DNA by electrophoresis in agarose gels supplemented with a DNA-intercalating agent.

    PubMed

    Zhu, X Q; Chilton, N B; Gasser, R B

    1998-05-01

    This study evaluated the use of a commercially available DNA intercalating agent (Resolver Gold) in agarose gels for the direct detection of sequence variation in ribosomal DNA (rDNA). This agent binds preferentially to AT sequence motifs in DNA. Regions of nuclear rDNA, known to provide genetic markers for the identification of species of parasitic ascarid nematodes (order Ascaridida), were amplified by polymerase chain reaction (PCR) and subjected to electrophoresis in standard agarose gels versus gels supplemented with Resolver Gold. Individual taxa examined could not be distinguished reliably based on the size of their amplicons in standard agarose gels, whereas they could be readily delineated based on mobility using Resolver Gold-supplemented gels. The latter was achieved because of differences (approximately 0.1-8.2%) in the AT content of the fragments among different taxa, which were associated with significant interspecific differences (approximately 11-39%) in the rDNA sequences employed. There was a tendency for fragments with higher AT content to migrate slower in supplemented agarose gels compared with those of lower AT content. The results indicate the usefulness of this electrophoretic approach to rapidly screen for sequence variability within or among PCR-amplified rDNA fragments of similar sizes but differing AT contents. Although evaluated on rDNA of parasites, the approach has potential to be applied to a range of genes of different groups of infectious organisms. PMID:9629896

  12. Subpopulations of liver coated vesicles resolved by preparative agarose gel electrophoresis

    SciTech Connect

    Kedersha, N.L.; Hill, D.F.; Kronquist, K.E.; Rome, L.H.

    1986-01-01

    Rat liver clathrin coated vesicles (CVs) were separated into several distinct subpopulations using non-sieving concentrations of agarose, which allowed the separation of species differing primarily in surface charge. Using preparative agarose electrophoresis, the CVs were recovered and analyzed for differences in morphology, coat protein composition, and stripped vesicle protein composition. Coat proteins from difference populations appeared identical on SDS PAGE, and triskelions stripped from the different populations showed the same mobility on the agarose gel, suggesting that the mobility differences observed in intact CVs were due to differences in the surface charge of underlying vesicles rather than to variations in their clathrin coats. Stripped CVs exhibited considerable heterogeneity when analyzed by Western blotting: the fast-migrating population was enriched in the mannose 6-phosphate receptor, secretory acetyl-choline esterase, and an M/sub r/ 195,000 glycoprotein. The slow-migrating population of CVs was enriched in the asialoglycoprotein receptor, and it appeared to contain all detectable concanavalin A-binding polypeptides as well as the bulk of detectable WGA-binding proteins. When CVs were prepared from /sup 125/I-asialoorosomucoid-perfused rat liver, ligand was found in the slow-migrating CVs, suggesting that these were endocytic in origin. Morphological differences were also observed: the fast-migrating population was enriched in smaller CVs, whereas the slow-migrating population exhibited an enrichment in larger CVs. As liver consists largely of hepatocytes, these subpopulations appear to originate from the same cell type and probably represent CVs of different intracellular origin and destination.

  13. [Agarose gel isoelectric focusing: application to the study of abnormalities of immunoglobulin clonality in CSF and serum].

    PubMed

    Lebrun-Fourcy, C; Rondot, J; Revol, C; Renversez, J C

    1996-01-01

    Since it is quite difficult to commonly use isoelectric focusing (IEF) of proteins in polyacrylamide gel for biological diagnosis, we have developed a method based on IEF in agarose gel, to split proteins from sera and cerebrospinal fluid (CSF). A prefocalisation at low voltage (250 V) is made on a custom thin gel of agarose (0.5 mm) containing some carrier ampholytes (pH 5-9). After deposition of biological samples, the gel is run at 500 V, thereafter at 1200 V. After focusing, the gel is fixed before being coloured by a simplified silver staining technique. In order to demonstrate the good resolution of the immunoglobulines (Ig) in the pH gradient, a transfer on a nitrocellulose membrane followed by an immunofixation was carried out from unstained gels after IEF. This separation on agarose gel shows several advantages, ie its speed (3H total), its lack of toxicity, its sensibility and its reproductibility. It is specially well suited for the diagnosis of diseases characterised by oligoclonal or monoclonal Ig, particularly those found in the CSF during neurologic diseases like multiple sclerosis. Several examples of focused sera and CSF are reviewed in the paper. PMID:8952725

  14. Screening for amyloid aggregation by Semi-Denaturing Detergent-Agarose Gel Electrophoresis.

    PubMed

    Halfmann, Randal; Lindquist, Susan

    2008-01-01

    Amyloid aggregation is associated with numerous protein misfolding pathologies and underlies the infectious properties of prions, which are conformationally self-templating proteins that are thought to have beneficial roles in lower organisms. Amyloids have been notoriously difficult to study due to their insolubility and structural heterogeneity. However, resolution of amyloid polymers based on size and detergent insolubility has been made possible by Semi-Denaturing Detergent-Agarose Gel Electrophoresis (SDD-AGE). This technique is finding widespread use for the detection and characterization of amyloid conformational variants. Here, we demonstrate an adaptation of this technique that facilitates its use in large-scale applications, such as screens for novel prions and other amyloidogenic proteins. The new SDD-AGE method uses capillary transfer for greater reliability and ease of use, and allows any sized gel to be accomodated. Thus, a large number of samples, prepared from cells or purified proteins, can be processed simultaneously for the presence of SDS-insoluble conformers of tagged proteins. PMID:19066511

  15. Evaluation of agarose gel electrophoresis for characterization of silver nanoparticles in industrial products.

    PubMed

    Jimenez, Maria S; Luque-Alled, Jose M; Gomez, Teresa; Castillo, Juan R

    2016-05-01

    Agarose gel electrophoresis (AGE) has been used extensively for characterization of pure nanomaterials or mixtures of pure nanomaterials. We have evaluated the use of AGE for characterization of Ag nanoparticles (NPs) in an industrial product (described as strong antiseptic). Influence of different stabilizing agents (PEG, SDS, and sodium dodecylbenzenesulfonate), buffers (TBE and Tris Glycine), and functionalizing agents (mercaptosuccinic acid (TMA) and proteins) has been investigated for the characterization of AgNPs in the industrial product using different sizes-AgNPs standards. The use of 1% SDS, 0.1% TMA, and Tris Glycine in gel, electrophoresis buffer and loading buffer led to the different sizes-AgNPs standards moved according to their size/charge ratio (obtaining a linear relationship between apparent mobility and mean diameter). After using SDS and TMA, the behavior of the AgNPs in the industrial product (containing a casein matrix) was completely different, being not possible their size characterization. However we demonstrated that AGE with LA-ICP-MS detection is an alternative method to confirm the protein corona formation between the industrial product and two proteins (BSA and transferrin) maintaining NPs-protein binding (what is not possible using SDS-PAGE). PMID:26864499

  16. Photoinduced Oxidative DNA Damage Revealed by an Agarose Gel Nicking Assay: A Biophysical Chemistry Laboratory Experiment

    NASA Astrophysics Data System (ADS)

    Shafirovich, Vladimir; Singh, Carolyn; Geacintov, Nicholas E.

    2003-11-01

    Oxidative damage of DNA molecules associated with electron-transfer reactions is an important phenomenon in living cells, which can lead to mutations and contribute to carcinogenesis and the aging processes. This article describes the design of several simple experiments to explore DNA damage initiated by photoinduced electron-transfer reactions sensitized by the acridine derivative, proflavine (PF). A supercoiled DNA agarose gel nicking assay is employed as a sensitive probe of DNA strand cleavage. A low-cost experimental and computer-interfaced imaging apparatus is described allowing for the digital recording and analysis of the gel electrophoresis results. The first experiment describes the formation of direct strand breaks in double-stranded DNA induced by photoexcitation of the intercalated PF molecules. The second experiment demonstrates that the addition of the well-known electron acceptor, methylviologen, gives rise to a significant enhancement of the photochemical DNA strand cleavage effect. This occurs by an electron transfer step to methylviologen that renders the inital photoinduced charge separation between photoexcited PF and DNA irreversible. The third experiment demonstrates that the action spectrum of the DNA photocleavage matches the absorption spectrum of DNA-bound, intercalated PF molecules, which differs from that of free PF molecules. This result demonstrates that the photoinduced DNA strand cleavage is initiated by intercalated rather than free PF molecules.

  17. Mucin Agarose Gel Electrophoresis: Western Blotting for High-molecular-weight Glycoproteins.

    PubMed

    Ramsey, Kathryn A; Rushton, Zachary L; Ehre, Camille

    2016-01-01

    Mucins, the heavily-glycosylated proteins lining mucosal surfaces, have evolved as a key component of innate defense by protecting the epithelium against invading pathogens. The main role of these macromolecules is to facilitate particle trapping and clearance while promoting lubrication of the mucosa. During protein synthesis, mucins undergo intense O-glycosylation and multimerization, which dramatically increase the mass and size of these molecules. These post-translational modifications are critical for the viscoelastic properties of mucus. As a result of the complex biochemical and biophysical nature of these molecules, working with mucins provides many challenges that cannot be overcome by conventional protein analysis methods. For instance, their high-molecular-weight prevents electrophoretic migration via regular polyacrylamide gels and their sticky nature causes adhesion to experimental tubing. However, investigating the role of mucins in health (e.g., maintaining mucosal integrity) and disease (e.g., hyperconcentration, mucostasis, cancer) has recently gained interest and mucins are being investigated as a therapeutic target. A better understanding of the production and function of mucin macromolecules may lead to novel pharmaceutical approaches, e.g., inhibitors of mucin granule exocytosis and/or mucolytic agents. Therefore, consistent and reliable protocols to investigate mucin biology are critical for scientific advancement. Here, we describe conventional methods to separate mucin macromolecules by electrophoresis using an agarose gel, transfer protein into nitrocellulose membrane, and detect signal with mucin-specific antibodies as well as infrared fluorescent gel reader. These techniques are widely applicable to determine mucin quantitation, multimerization and to test the effects of pharmacological compounds on mucins. PMID:27341489

  18. Apatite formed on/in agarose gel as a bone-grafting material in the treatment of periodontal infrabony defect.

    PubMed

    Tabata, Masashi; Shimoda, Toru; Sugihara, Kazumasa; Ogomi, Daisuke; Ohgushi, Hajime; Akashi, Mitsuru

    2005-11-01

    The present study was designed to evaluate the effects of a hydroxyapatite/agarose (HA/agarose) composite gel formed by a novel alternate soaking process for the treatment of periodontal infrabony defects in three dogs. After creating two-wall infrabony periodontal defects on the medial aspect of the maxillary and mandibular second and forth premolars, the defects were implanted with temporary dental filling material (stopping) to induce inflammatory periodontal disease. Two months later, the mucoperiosteal flaps were raised, and after debridement, the infrabony defects were filled with one of the following three materials: (a) HA/agarose, (b) Bone ject (True-Bone Ceramic-collagen combined bone graft material, Koken, Japan), or (c) no material implantation (negative control). The animals were then randomly scheduled for sacrifice at 1, 2, and 6 months, and samples were taken for histological examination. In the HA/agarose gels, the 2-month postoperative cavities exhibited regeneration to new attachments with the apposition of a new cementum and well-oriented fibers. The neocementum was narrow and acellular, and the new bone apposition was limited. Six months postoperatively, newly formed bone was predominantly observed. The neocementum was wider and cellular. In the negative control, the 2-month postoperative cavities exhibited no regeneration of the cementum, nor any formation of periodontal pockets. The six-month postoperative cavities were nearly the same as the 2-month cavities. The Bone ject, 2-month postoperative cavities exhibited no regeneration of the periodontal tissue, nor any formation of periodontal pockets. Six months postoperatively, inflammatory granulation tissue was observed around the particles. The present study suggests that HA/agarose gels may play an important role in the regeneration of lost periodontal tissue. PMID:16034996

  19. Rheological and mechanical behavior of polyacrylamide hydrogels chemically crosslinked with allyl agarose for two-dimensional gel electrophoresis.

    PubMed

    Suriano, R; Griffini, G; Chiari, M; Levi, M; Turri, S

    2014-02-01

    Two-dimensional (2-D) gel electrophoresis currently represents one of the most standard techniques for protein separation. In addition to the most commonly employed polyacrylamide crosslinked hydrogels, acrylamide-agarose copolymers have been proposed as promising systems for separation matrices in 2-D electrophoresis, because of the good resolution of both high and low molecular mass proteins made possible by careful control and optimization of the hydrogel pore structure. As a matter of fact, a thorough understanding of the nature of the hydrogel pore structure as well as of the parameters by which it is influenced is crucial for the design of hydrogel systems with optimal sieving properties. In this work, a series of acrylamide-based hydrogels covalently crosslinked with different concentrations of allyl agarose (0.2-1%) is prepared and characterized by creep-recovery measurements, dynamic rheology and tensile tests, in the attempt to gain a clearer understanding of structure-property relationships in crosslinked polyacrylamide-based hydrogels. The rheological and mechanical properties of crosslinked acrylamide-agarose hydrogels are found to be greatly affected by crosslinker concentration. Dynamic rheological tests show that hydrogels with a percentage of allyl agarose between 0.2% and 0.6% have a low density of elastically effective crosslinks, explaining the good separation of high molecular mass proteins in 2-D gel electrophoresis. Over the same range of crosslinker concentration, creep-recovery measurements reveal the presence of non-permanent crosslinks in the hydrogel network that justifies the good resolution of low molecular mass proteins as well. In tensile tests, the hydrogel crosslinked with 0.4% of allyl agarose exhibits the best results in terms of mechanical strength and toughness. Our results show how the control of the viscoelastic and the mechanical properties of these materials allow the design of mechanically stable hydrogels with improved

  20. Morphology and mechanical properties of bicontinuous gels of agarose and gelatin and the effect of added lipid phase.

    PubMed

    Shrinivas, Preeti; Kasapis, Stefan; Tongdang, Taewee

    2009-08-01

    This study examines the structural properties of binary and tertiary mixtures made of the cold-setting biopolymers agarose and gelatin and a lipid phase with solid or liquid-like viscoelasticity. The working protocol included the techniques of small-deformation dynamic oscillation on shear, modulated differential scanning calorimetry and scanning electron microscopy, and theoretical modeling that adapted ideas of relating the morphology to the elastic modulus of synthetic polyblends and block polymers. The experimental setting was designed to encourage extensive phase separation in the binary gel of agarose and gelatin whose mechanical properties were rationalized on the basis of a bicontinuous blending law. The presence of two continuous phases allowed the slower-gelling component (gelatin) to exhibit favorable relative affinity for the solvent with increasing concentrations of the protein in the system. This is an unexpected outcome that contradicts the central finding of a single value of the p factor observed in the distribution of solvent between the continuous matrix and discontinuous inclusions of deswelled binary gels reported earlier in the literature. The incorporation of a lipid phase of effectively zero elastic modulus or in excess of 10(8) Pa in the composite aqueous gel weakens or reinforces the matrix accordingly. The elastic moduli and morphology of the tertiary blend were related to changing the relative phase volumes of components using analytical expressions of isotropically dispersed soft or rigid filler particles in a polymeric matrix. PMID:19397252

  1. Serum protein electrophoresis by using high-resolution agarose gel in clinically healthy and Aspergillus species-infected falcons.

    PubMed

    Kummrow, Maya; Silvanose, Christudas; Di Somma, Antonio; Bailey, Thomas A; Vorbrüggen, Susanne

    2012-12-01

    Serum protein electrophoresis has gained importance in avian medicine during the past decade. Interpretation of electrophoretic patterns should be based on species-specific reference intervals and the electrophoresis gel system. In this study, serum protein electrophoresis by using high-resolution agarose gels was performed on blood samples collected from 105 falcons, including peregrine falcons (Falco peregrinus), gyrfalcons (Falco rusticolus), saker falcons (Falco cherrug), red-naped shaheens (Falco pelegrinoides babylonicus), and hybrid falcons, that were submitted to the Dubai Falcon Hospital (Dubai, United Arab Emirates) between 2003 and 2006. Reference values were established in clinically healthy birds and compared with values from falcons infected with Aspergillus species (n = 32). Falcons with confirmed aspergillosis showed significantly lower prealbumin values, which is a novel finding. Prealbumin has been documented in many avian species, but further investigation is required to illuminate the diagnostic significance of this negative acute-phase protein. PMID:23409432

  2. A thin-layer multistrip agarose gel electrophoresis apparatus for Ferguson plot analysis at the sub-microgram load level.

    PubMed

    Orbàn, L; Sullivan, J V; Chrambach, A

    1989-07-01

    A method for the simultaneous horizontal agarose gel electrophoresis on thin-layer strips of different gel concentrations was developed for the purpose of generating Ferguson plots at the sub-microgram load level. Seven independent gel strips on a common GelBond support were formed by filling channels created by a comb-shaped spacer (polycarbonate) in a vertical multistrip cassette. Electrophoresis on a horizontal Peltier-cooled surface employed commercial apparatus (E-C Apparatus Corp.) with a modified cover which is airtight and holds anodic and cathodic voltage measurement probes for each strip. The application of the apparatus to Ferguson plot analysis in a single experiment was exemplified on the RNA-containing turnip crinkle virus (TCV) at a load of 50 ng/gel strip, using an optimized silver staining method (a modification of a procedure of FMC Corp. BioProducts) for detection. Within the range of 3.5 to 12.5 V/cm, the plot was found to be independent of field strength. Mobility is also independent of the concentration of detergent (CHAPS) up to 10 mM. PMID:2809063

  3. Determining iron oxide nanoparticle heating efficiency and elucidating local nanoparticle temperature for application in agarose gel-based tumor model.

    PubMed

    Shah, Rhythm R; Dombrowsky, Alexander R; Paulson, Abigail L; Johnson, Margaret P; Nikles, David E; Brazel, Christopher S

    2016-11-01

    Magnetic iron oxide nanoparticles (MNPs) have been developed for magnetic fluid hyperthermia (MFH) cancer therapy, where cancer cells are treated through the heat generated by application of a high frequency magnetic field. This heat has also been proposed as a mechanism to trigger release of chemotherapy agents. In each of these cases, MNPs with optimal heating performance can be used to maximize therapeutic effect while minimizing the required dosage of MNPs. In this study, the heating efficiencies (or specific absorption rate, SAR) of two types of MNPs were evaluated experimentally and then predicted from their magnetic properties. MNPs were also incorporated in the core of poly(ethylene glycol-b-caprolactone) micelles, co-localized with rhodamine B fluorescent dye attached to polycaprolactone to monitor local, nanoscale temperatures during magnetic heating. Despite a relatively high SAR produced by these MNPs, no significant temperature rise beyond that observed in the bulk solution was measured by fluorescence in the core of the magnetic micelles. MNPs were also incorporated into a macro-scale agarose gel system that mimicked a tumor targeted by MNPs and surrounded by healthy tissues. The agarose-based tumor models showed that targeted MNPs can reach hyperthermia temperatures inside a tumor with a sufficient MNP concentration, while causing minimal temperature rise in the healthy tissue surrounding the tumor. PMID:27523991

  4. Quantification of DNA by Agarose Gel Electrophoresis and Analysis of the Topoisomers of Plasmid and M13 DNA Following Treatment with a Restriction Endonuclease or DNA Topoisomerase I

    ERIC Educational Resources Information Center

    Tweedie, John W.; Stowell, Kathryn M.

    2005-01-01

    A two-session laboratory exercise for advanced undergraduate students in biochemistry and molecular biology is described. The first session introduces students to DNA quantification by ultraviolet absorbance and agarose gel electrophoresis followed by ethidium bromide staining. The second session involves treatment of various topological forms of…

  5. DNA electrophoresis in agarose gels: Effects of electric field and gel concentration on the exponential dependence of reciprocal mobility on DNA length

    NASA Astrophysics Data System (ADS)

    Beheshti, Afshin; van Winkle, David; Randolph, Rill

    2002-03-01

    Electrophoresis was performed on double stranded DNA fragments ranging in length from 200 bp to 48502 bp at agarose gel concentrations T = 0.5% - 1.5% and electric fields E = 0.71 V/cm to 5 V/cm. A wide range of electric fields and gel concentrations were used to find what range of conditions work with the new interpolation equation, 1/μ(L) = 1/μl - (1/μl - 1/μ_s)e^-L/γ. The equation fit extremely well (\\chi^2 >= 0.999) to data with E = 2.5 V/cm to 5 V/cm and for lower fields (E < 2.5 V/cm) at low gel concentrations (T = 0.5% and 0.7%). This exponential relation seemed to hold when there is a smooth transition from the Ogston sieving regime to the reptation regime when looking at the “reptation plots” (plotting 3μL/μo vs. L) (Rousseau, J., Drouin, G., and Slater, G. W., Phys Rev Lett. 1997, 79, 1945-1948). For separations of single-stranded DNA in polyacrylamide, similar reptation plots have a region with a negative slope between the Ogston sieving regime and the reptation regime which has been interpreted as the signature of entropic trapping. When separating double-stranded DNA in agarose it was observed that fits deviate from the data when three different slopes are observed in the reptation plots. Failure of the simple exponential relationship between reciprocal mobility and DNA length appears to be the consequence of entropic trapping.

  6. Beverage-Agarose Gel Electrophoresis: An Inquiry-Based Laboratory Exercise with Virtual Adaptation

    ERIC Educational Resources Information Center

    Cunningham, Steven C.; McNear, Brad; Pearlman, Rebecca S.; Kern, Scott E.

    2006-01-01

    A wide range of literature and experience has shown that teaching methods that promote active learning, such as inquiry-based approaches, are more effective than those that rely on passive learning. Gel electrophoresis, one of the most common laboratory techniques in molecular biology, has a wide range of applications in the life sciences. As…

  7. Evaluation of the friction coefficient, the radial stress, and the damage work during needle insertions into agarose gels.

    PubMed

    Urrea, Fabián A; Casanova, Fernando; Orozco, Gustavo A; García, José J

    2016-03-01

    Agarose hydrogels have been extensively used as a phantom material to mimic the mechanical behavior of soft biological tissues, e.g. in studies aimed to analyze needle insertions into the organs producing tissue damage. To better predict the radial stress and damage during needle insertions, this study was aimed to determine the friction coefficient between the material of commercial catheters and hydrogels. The friction coefficient, the tissue damage and the radial stress were evaluated at 0.2, 1.8, and 10mm/s velocities for 28, 30, and 32 gauge needles of outer diameters equal to 0.36, 0.31, and 0.23mm, respectively. Force measurements during needle insertions and retractions on agarose gel samples were used to analyze damage and radial stress. The static friction coefficient (0.295±0.056) was significantly higher than the dynamic (0.255±0.086). The static and dynamic friction coefficients were significantly smaller for the 0.2mm/s velocity compared to those for the other two velocities, and there was no significant difference between the friction coefficients for 1.8 and 10mm/s. Radial stress averages were 131.2±54.1, 248.3±64.2, and 804.9±164.3Pa for the insertion velocity of 0.2, 1.8, and 10mm/s, respectively. The radial stress presented a tendency to increase at higher insertion velocities and needle size, which is consistent with other studies. However, the damage work did not show to be a good predictor of tissue damage, which appears to be due to simplifications in the analytical model. Differently to other approaches, the method proposed here based on radial stress may be extended in future studies to quantity tissue damage in vivo along the entire needle track. PMID:26700572

  8. Immunoassay principle based on exchange reactions: investigations on agarose gel and silanized quartz.

    PubMed

    Weber, A; Ogendal, L H

    1992-01-01

    Preliminary studies of a new immunoassay principle based on exchange reactions is reported. Exchange of 125I-labelled insulin with unlabelled insulin from immobilized monoclonal antibodies was investigated. From antibody immobilized on a gel substrate the tagged insulin was exchanged according to a first-order process. With antibody immobilized on a quartz substrate by two different methods, the kinetics was changed dramatically, probably because of the non-specific interaction between the ligand and the surface. The recorded adsorption isotherms could not be described by the Langmuir adsorption equation, and a model allowing for non-specific adsorption of the ligand was developed. This model gave a satisfactory fit to the experimental data, allowing computation of adsorption parameters. It is concluded that even the best method used to immobilize receptors on quartz is not adequate for an exchange assay to be made. However, this coating method may lead to more sensitive receptor-based assays of more conventional type. PMID:1379052

  9. Synthesis Rates and Binding Kinetics of Matrix Products in Engineered Cartilage Constructs Using Chondrocyte-Seeded Agarose Gels

    PubMed Central

    Nims, Robert J.; Cigan, Alexander D.; Albro, Michael B.; Hung, Clark T.; Ateshian, Gerard A.

    2013-01-01

    Large-sized cartilage constructs suffer from inhomogeneous extracellular matrix deposition due to insufficient nutrient availability. Computational models of nutrient consumption and tissue growth can be utilized as an efficient alternative to experimental trials to optimize the culture of large constructs; models require system-specific growth and consumption parameters. To inform models of the [bovine chondrocyte]-[agarose gel] system, total synthesis rate (matrix accumulation rate + matrix release rate) and matrix retention fractions of glycosaminoglycans (GAG), collagen, and cartilage oligomeric matrix protein (COMP) were measured either in the presence (continuous or transient) or absence of TGF-β3 supplementation. TGF-β3’s influence on pyridinoline content and mechanical properties was also measured. Reversible binding kinetic parameters were characterized using computational models. Based on our recent nutrient supplementation work, we measured glucose consumption and critical glucose concentration for tissue growth to computationally simulate the culture of a human patella-sized tissue construct, reproducing the experiment of Hung et al., (2003). Transient TGF-β3 produced the highest GAG synthesis rate, highest GAG retention ratio, and highest binding affinity; collagen synthesis was elevated in TGF-β3 supplementation groups over control, with the highest binding affinity observed in the transient supplementation group; both COMP synthesis and retention were lower than those for GAG and collagen. These results informed the modeling of GAG deposition within a large patella construct; this computational example was similar to previous experimental results without further adjustments to modeling parameters. These results suggest that these nutrient consumption and matrix synthesis models are an attractive alternative for optimizing the culture of large-sized constructs. PMID:24284199

  10. Biomimetic materials processing: Implementation of molecular imprinting and study of biomineralization through the development of an agarose gel assay

    NASA Astrophysics Data System (ADS)

    Boggavarapu, Sajiv

    agarose gel matrix for studying inhibition and growth as influenced by various organic molecule functionalities. The gel mineralization assay is a novel approach in which quantitative and qualitative data could be generated in a high throughput fashion to determine organic molecule mediation of calcium based crystal growth. Such methods provide an approach for eventually providing control in development of synthetic biocomposites with customized materials properties.

  11. A charge-coupled-device camera image analysis system for quantifying DNA distributions in agarose gels after pulsed-field gel electrophoresis

    SciTech Connect

    Dewey, W.C.; Thompson, L.L.; Trinh, M.L.; Latz, D.L. |; Ward, J.F.

    1994-10-01

    A charge-coupled-device camera system was coupled to a personal computer and, with uniformity in illumination and detection (within 4-8%) along each lane, was used for quantifying the distribution of DNA molecules that migrate from the PFGE well (plug) into the lane at distances varying from 1 to 50 mm (with 0.5 mm/pixel). By using a specially designed transmission filter for transmitting 470-725 nm fluorescence from ethidium bromide-stained DNA while eliminating most of the fluorescence (<400 nm) from the agarose gel, and by using neutral density filters to prevent saturation of the camera, the fluorescence intensity is linearly related to the amount of DNA varying from {approximately} 0.03 {mu}g in a 3-mm-diameter cylindrical plug 5 mm long (equal to background) to {approximately} 4 {mu}g (where ethidium bromide staining saturates). The percentage DNA released from the plug and distribution in the lane (with 1-2 mm resolution) obtained by quantifying DNA fluorescence were not significantly different from the same data obtained by analysis of radioactivity of the same DNA labeled with [{sup 3}H]dThd. However, scattering of fluorescence from one lane into an adjacent lane 3 mm away and as far as 10 mm from the plug into the lane presented a problem. This problem was overcome by using a form with slots to cover every other lane when the images were obtained and either (1) cutting the lane from the plug and moving it 15 mm away or (2) imaging the intact gel and applying a correction for {approximately} 7% of the fluorescence from the plug tailing out {approximately} 10 mm beyond the first 1 mm in the lane. In addition, the following were required: (1) carefully controlled staining and destaining procedures, and (2) a low background that is obtained as an average uniform background in each lane 5 mm beyond where DNA migration stops. 31 refs., 7 figs.

  12. Gel retarder for fire prevention and extinguishing -- Its application for spontaneous combustion of coal seams

    SciTech Connect

    1998-12-31

    With its unique function, gel retarder has been successfully applied to extinguish fire at coal face, roadways and stop line of upper slice extraction, and a comparably perfect set of fire extinguishing techniques has been developed. The technique gathers together characteristics of water-fixation, leak-blocking, cooling, oxidation-retarding and heat-resisting. A new agglomerating agent without amine and corrosion has been developed to replace amine-salt and acid used in the past. Gel-injection technology cooperating with the grouting system on the ground solves previous problems in which gel-injection velocity was slow and materials transport was difficult. The technique has become the main measure to extinguish spontaneous combustion in coal mines in China. The use of gel retarder as an important means of underground fire prevention will be applied more widely to prevent and extinguish spontaneous fire in coal mines.

  13. Effect of Polyethylene Glycol on Properties and Drug Encapsulation-Release Performance of Biodegradable/Cytocompatible Agarose-Polyethylene Glycol-Polycaprolactone Amphiphilic Co-Network Gels.

    PubMed

    Chandel, Arvind K Singh; Kumar, Chinta Uday; Jewrajka, Suresh K

    2016-02-10

    We synthesized agarose-polycaprolactone (Agr-PCL) bicomponent and Agr-polyethylene glycol-PCL (Agr-PEG-PCL) tricomponent amphiphilic co-network (APCN) gels by the sequential nucleophilic substitution reaction between amine-functionalized Agr and activated halide terminated PCL or PCL-b-PEG-b-PCL copolymer for the sustained and localized delivery of hydrophilic and hydrophobic drugs. The biodegradability of the APCNs was confirmed using lipase and by hydrolytic degradation. These APCN gels displayed good cytocompatibility and blood compatibility. Importantly, these APCN gels exhibited remarkably high drug loading capacity coupled with sustained and triggered release of both hydrophilic and hydrophobic drugs. PEG in the APCNs lowered the degree of phase separation and enhanced the mechanical property of the APCN gels. The drug loading capacity and the release kinetics were also strongly influenced by the presence of PEG, the nature of release medium, and the nature of the drug. Particularly, PEG in the APCN gels significantly enhanced the 5-fluorouracil loading capacity and lowered its release rate and burst release. Release kinetics of highly water-soluble gemcitabine hydrochloride and hydrophobic prednisolone acetate depended on the extent of water swelling of the APCN gels. Cytocompatibility/blood compatibility and pH and enzyme-triggered degradation together with sustained release of drugs show great promise for the use of these APCN gels in localized drug delivery and tissue engineering applications. PMID:26760672

  14. Development of a chamber system for rapid, high yield and cost-effective purification of deoxyribonucleic acid fragments from agarose gel

    PubMed Central

    Eslami, Gilda; Salehi, Rasoul

    2014-01-01

    Background: There are several methods commonly practicing for deoxyribonucleic acid (DNA) purification from agarose gel. In most laboratories, especially in developing countries, present methods for recovering of DNA fragments from the gel are mostly involved organic solvents. However, manual purification using organic solvents are toxic, labor intensive, time consuming and prone to contamination owing to several handling steps. The above mentioned burdens as well as cost and long time to import them, especially in developing countries, prompted us to design and develop a chamber system for rapid, non-toxic, cost-effective and user friendly device for polymerase chain reaction (PCR) products purification from agarose gel. Materials and Methods: The device was made from plexiglass plates. After amplification of two fragments of 250 and 850 bp, PCR products were electrophoresed. Subsequently, the desired bands were excised and purified with three method: HiPer Mini chamber, phenol extraction method and spin column procedure. To assess the suitability of the purified DNAs, restriction digestion was applied. Results: Results showed that the yield of recovered DNA in our method was above 95%, whereas the yields obtained with conventional phenol extraction and spin column methods were around 60%. Conclusion: In conclusion, the current method for DNA elution is quick, inexpensive and robust and it does not require the use of toxic organic solvents. In addition, the purified DNA was well has suited for further manipulations such as restriction digestion, ligation, cloning, sequencing and hybridization. PMID:24761386

  15. A subtle calculation method for nanoparticle’s molar extinction coefficient: The gift from discrete protein-nanoparticle system on agarose gel electrophoresis

    NASA Astrophysics Data System (ADS)

    Zhong, Ruibo; Yuan, Ming; Gao, Haiyang; Bai, Zhijun; Guo, Jun; Zhao, Xinmin; Zhang, Feng

    2016-03-01

    Discrete biomolecule-nanoparticle (NP) conjugates play paramount roles in nanofabrication, in which the key is to get the precise molar extinction coefficient of NPs. By making best use of the gift from a specific separation phenomenon of agarose gel electrophoresis (GE), amphiphilic polymer coated NP with exact number of bovine serum albumin (BSA) proteins can be extracted and further experimentally employed to precisely calculate the molar extinction coefficient of the NPs. This method could further benefit the evaluation and extraction of any other dual-component NP-containing bio-conjugates.

  16. Study of kinetic desorption rate constant in fish muscle and agarose gel model using solid phase microextraction coupled with liquid chromatography with tandem mass spectrometry.

    PubMed

    Togunde, Oluranti Paul; Oakes, Ken; Servos, Mark; Pawliszyn, Janusz

    2012-09-12

    This study aims to use solid phase microextraction (SPME), a simple tool to investigate diffusion rate (time) constant of selected pharmaceuticals in gel and fish muscle by comparing desorption rate of diffusion of the drugs in both agarose gel prepared with phosphate-buffered saline (PBS; pH 7.4) and fish muscle. The gel concentration (agarose gel model) that could be used to simulate tissue matrix (fish muscle) for free diffusion of drugs under in vitro and in vivo conditions was determined to model mass transfer phenomena between fibre polymer coating and environmental matrix such that partition coefficients and desorption time constant (diffusion coefficient) can be determined. SPME procedure involves preloading the extraction phase (fibre) with the standards from spiked PBS for 1h via direct extraction. Subsequently, the preloaded fibre is introduced to the sample such fish or agarose gel for specified time ranging from 0.5 to 60 h. Then, fibre is removed at specified time and desorbed in 100 μL of desorption solution (acetonitrile: water 1:1) for 90 min under agitation speed of 1000 rpm. The samples extract were immediately injected to the instrument and analysed using liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS). The limit of detection of the method in gel and fish muscle was 0.01-0.07 ng mL(-1) and 0.07-0.34 ng g(-1), respectively, while the limit quantification was 0.10-0.20 ng mL(-1) in gel samples and 0.40-0.97 ng g(-1) in fish sample. The reproducibility of the method was good (5-15% RSD). The results suggest that kinetics of desorption of the compounds in fish tissue and different viscosity of gel can be determined using desorption time constant. In this study, desorption time constant which is directly related to desorption rate (diffusion kinetics) of selected drugs from the fibre to the gel matrix is faster as the viscosity of the gel matrix reduces from 2% (w/v) to 0.8% (w/v). As the concentration of gel reduces

  17. Identification of putative genes involved in the development of Tuber borchii fruit body by mRNA differential display in agarose gel.

    PubMed

    Zeppa, Sabrina; Guidi, Chiara; Zambonelli, Alessandra; Potenza, Lucia; Vallorani, Luciana; Pierleoni, Raffaella; Sacconi, Cinzia; Stocchi, Vilberto

    2002-12-01

    In order to analyse gene expression during fruit body development of the ectomychorrizal fungus Tuber borchii Vittad., a modified differential display procedure was set up. The procedure used is easier and faster than the traditional one and generates reproducible cDNA banding patterns that can be resolved on a standard ethidium bromide-agarose gel. From 16 cDNA fingerprints, 25 amplicons with apparent differential expression were identified and cloned without a previous reamplification. Fifteen clones showed significant similarity to known proteins that are involved in dikaryosis and fruiting, cell division, transport across membranes, mitochondrial division, intermediary metabolism, biosynthesis of isoprenoid compounds and putative RNA/DNA binding. Northern blot analyses confirmed that seven cDNAs were indeed differentially expressed during fruit body development. The characterisation of these cDNAs represents a starting point in understanding the molecular mechanisms of cellular differentiation leading to the development of the T. borchii fruit body. PMID:12491010

  18. Identification of column edges of DNA fragments by using K-means clustering and mean algorithm on lane histograms of DNA agarose gel electrophoresis images

    NASA Astrophysics Data System (ADS)

    Turan, Muhammed K.; Sehirli, Eftal; Elen, Abdullah; Karas, Ismail R.

    2015-07-01

    Gel electrophoresis (GE) is one of the most used method to separate DNA, RNA, protein molecules according to size, weight and quantity parameters in many areas such as genetics, molecular biology, biochemistry, microbiology. The main way to separate each molecule is to find borders of each molecule fragment. This paper presents a software application that show columns edges of DNA fragments in 3 steps. In the first step the application obtains lane histograms of agarose gel electrophoresis images by doing projection based on x-axis. In the second step, it utilizes k-means clustering algorithm to classify point values of lane histogram such as left side values, right side values and undesired values. In the third step, column edges of DNA fragments is shown by using mean algorithm and mathematical processes to separate DNA fragments from the background in a fully automated way. In addition to this, the application presents locations of DNA fragments and how many DNA fragments exist on images captured by a scientific camera.

  19. Temporal effect of inertial cavitation with and without microbubbles on surface deformation of agarose S gel in the presence of 1-MHz focused ultrasound.

    PubMed

    Tomita, Y; Matsuura, T; Kodama, T

    2015-01-01

    Sonoporation has the potential to deliver extraneous molecules into a target tissue non-invasively. There have been numerous investigations of cell membrane permeabilization induced by microbubbles, but very few studies have been carried out to investigate sonoporation by inertial cavitation, especially from a temporal perspective. In the present paper, we show the temporal variations in nano/micro-pit formations following the collapse of inertial cavitation bubbles, with and without Sonazoid® microbubbles. Using agarose S gel as a target material, erosion experiments were conducted in the presence of 1-MHz focused ultrasound applied for various exposure times, Tex (0.002-60 s). Conventional microscopy was used to measure temporal variations in micrometer-scale pit numbers, and atomic force microscopy utilized to detect surface roughness on a nanometer scale. The results demonstrated that nanometer-scale erosion was predominantly caused by Sonazoid® microbubbles and C4F10 gas bubbles for 0.002 s

  20. Application of urea-agarose gel electrophoresis to select non-redundant 16S rRNAs for taxonomic studies: palladium(II) removal bacteria.

    PubMed

    Assunção, Ana; Costa, Maria Clara; Carlier, Jorge Dias

    2016-03-01

    The 16S ribosomal RNA (rRNA) gene has been the most commonly used sequence to characterize bacterial communities. The classical approach to obtain gene sequences to study bacterial diversity implies cloning amplicons, selecting clones, and Sanger sequencing cloned fragments. A more recent approach is direct sequencing of millions of genes using massive parallel technologies, allowing a large-scale biodiversity analysis of many samples simultaneously. However, currently, this technique is still expensive when applied to few samples; therefore, the classical approach is still used. Recently, we found a community able to remove 50 mg/L Pd(II). In this work, aiming to identify the bacteria potentially involved in Pd(II) removal, the separation of urea/heat-denatured DNA fragments by urea-agarose gel electrophoresis was applied for the first time to select 16S rRNA-cloned amplicons for taxonomic studies. The major raise in the percentage of bacteria belonging to genus Clostridium sensu stricto from undetected to 21 and 41 %, respectively, for cultures without, with 5 and 50 mg/L Pd(II) accompanying Pd(II) removal point to this taxa as a potential key agent for the bio-recovery of this metal. Despite sulfate-reducing bacteria were not detected, the hypothesis of Pd(II) removal by activity of these bacteria cannot be ruled out because a slight decrease of sulfate concentration of the medium was verified and the formation of PbS precipitates seems to occur. This work also contributes with knowledge about suitable partial 16S rRNA gene regions for taxonomic studies and shows that unidirectional sequencing is enough when Sanger sequencing cloned 16S rRNA genes for taxonomic studies to genus level. PMID:26590590

  1. Controlled release and retarded leaching of pesticides by encapsulating in carboxymethyl chitosan /bentonite composite gel.

    PubMed

    Li, Jianfa; Yao, Jian; Li, Yimin; Shao, Ying

    2012-09-01

    A novel composite gel composed of carboxymethyl-chitosan (CM-chit) and bentonite (H-bent) was used as the carrier for encapsulating atrazine and imidacloprid to control their release in water and retard their leaching in soil. Strong interactions between CM-chit and H-bent in the composite were confirmed by FT-IR, and good dispersion of pesticides in the carrier was observed by SEM. According to the results of release experiments in water, the CM-chit/H-bent composite carrier showed double advantages of both encapsulation by the polymer and sorption by the bentonite. The time taken for 50 % of active ingredients to be released, t₅₀, was prolonged to 572 h for atrazine and 24 h for imidacloprid, respectively. The difference between the two pesticides on release behavior was related to their hydrophobicity and water solubility. Leaching experiments through a soil layer showed that this novel carrier reduced the amount of pesticides available for leaching, and would be useful for diminishing the environmental pollution of pesticides. PMID:22575006

  2. Optical investigation of diffusion of levofloxacin mesylate in agarose hydrogel

    NASA Astrophysics Data System (ADS)

    Tan, Shuaixia; Dai, Hongjun; Wu, Juejie; Zhao, Ning; Zhang, Xiaoli; Xu, Jian

    2009-09-01

    Real-time electronic speckle pattern interferometry method has been applied to study the diffusion behavior of levofloxacin mesylate (MSALVFX) in agarose hydrogel. The results show that the diffusivity of solute decreases with the increase of concentration of agarose and adapts to Kohlrausch's law. Furthermore, Amsden's model, based on the retardance effect associated with polymer chain flexibility, was employed to simulate the diffusion behavior. The consistent results suggest that the retardance effect dominates the diffusion process of MSALFVX in hydrogel; moreover, polymer chain flexibility greatly affects drug transport within the polymer matrix.

  3. In situ selective determination of methylmercury in river water by diffusive gradient in thin films technique (DGT) using baker's yeast (Saccharomyces cerevisiae) immobilized in agarose gel as binding phase.

    PubMed

    Tafurt-Cardona, Makenly; Eismann, Carlos Eduardo; Suárez, Carlos Alfredo; Menegário, Amauri Antonio; Luko, Karen Silva; Sargentini Junior, Ézio

    2015-08-01

    Saccharomyces cerevisiae immobilized in agarose gel as binding phase and polyacrylamide as diffusive layer in the diffusive gradient in thin films technique (DGT) was used for selective determination of methylmercury (MeHg). Deployment tests showed good linearity in mass uptake up to 48 h (3276 ng). When coupling the DGT technique with Cold Vapor Atomic Fluorescence Spectrometry, the method has a limit of detection of 0.44 ng L(-1) (pre concentration factor of 11 for 48 h deployment). Diffusion coefficient of 7.03 ± 0.77 × 10(-6) cm(2) s(-1) at 23 °C in polyacrylamide gel (pH = 5.5 and ionic strength = 0.05 mol L(-1) NaCl) was obtained. Influence of ionic strength (from 0.0005 mol L(-1) to 0.1 mol L(-1) NaCl) and pH (from 3.5 to 8.5) on MeHg uptake were evaluated. For these range, recoveries of 84-105% and 84-98% were obtained for ionic strength and pH respectively. Potential interference due to presence of Cu, Fe, Mn, Zn was also assessed showing good recoveries (70-87%). The selectivity of the proposed approach was tested by deployments in solutions containing MeHg and Hg(II). Results obtained showed recoveries of 102-115 % for MeHg, while the uptake of Hg(II) was insignificant. The proposed approach was successfully employed for in situ measurements in the Negro River (Manaus-AM, Brazil). PMID:26320783

  4. Estimating the DNA strand breakage using a fuzzy inference system and agarose gel electrophoresis, a case study with toothed carp Aphanius sophiae exposed to cypermethrin.

    PubMed

    Poorbagher, Hadi; Moghaddam, Maryam Nasrollahpour; Eagderi, Soheil; Farahmand, Hamid

    2016-07-01

    The DNA breakage has been widely used in ecotoxicological studies to investigate effects of pesticides in fishes. The present study used a fuzzy inference system to quantify the breakage of DNA double strand in Aphanius sophiae exposed to the cypermethrin. The specimens were adapted to different temperatures and salinity for 14 days and then exposed to cypermethrin. DNA of each specimens were extracted, electrophoresed and photographed. A fuzzy system with three input variables and 27 rules were defined. The pixel value curve of DNA on each gel lane was obtained using ImageJ. The DNA breakage was quantified using the pixel value curve and fuzzy system. The defuzzified values were analyzed using a three-way analysis of variance. Cypermethrin had significant effects on DNA breakage. Fuzzy inference systems can be used as a tool to quantify the breakage of double strand DNA. DNA double strand of the gill of A. sophiae is sensitive enough to be used to detect cypermethrin in surface waters in concentrations much lower than those reported in previous studies. PMID:27000282

  5. Use of pulsed-field agarose gel electrophoresis to size genomes of Campylobacter species and to construct a SalI map of Campylobacter jejuni UA580.

    PubMed

    Chang, N; Taylor, D E

    1990-09-01

    To determine the physical length of the chromosome of Campylobacter jejuni, the genome was subjected to digestion by a series of restriction endonucleases to produce a small number of large restriction fragments. These fragments were then separated by pulsed-field gel electrophoresis with the contour-clamped homogeneous electric field system. The DNA of C. jejuni, with its low G+C content, was found to have no restriction sites for enzymes NotI and SfiI, which cut a high-G+C regions. Most of the restriction enzymes that were used resulted in DNA fragments that were either too numerous or too small for genome size determination, with the exception of the enzymes SalI (5' ... G decreases TCGAG ... 3'), SmaI (5' .... CCC decreases GGG .... 3'), and KpnI (5' ... GGTAC decreases C .... 3'). With SalI, six restriction fragments with average values of 48.5, 80, 110, 220, 280, and 980 kilobases (kb) were obtained when calibrated with both a lambda DNA ladder and yeast Saccharomyces cerevisiae chromosome markers. The sum of these fragments yielded an average genome size of 1.718 megabases (Mb). With SmaI, nine restriction fragments with average values ranging from 39 to 371 kb, which yielded an average genome size of 1.726 Mb were obtained. With KpnI, 11 restriction fragments with sizes ranging from 35 to 387.5 kb, which yielded an average genome size of 1.717 Mb were obtained. A SalI restriction map was derived by partial digestion of the C. jejuni DNA. The genome sizes of C. laridis, C. coli, and C. fetus were also determined with the contour-clamped homogeneous electric field system by SalI, SmaI, and KpnI digestion. Average genome sizes were found to be 1.714 Mb for C. coli, 1.267 Mb for C. fetus subsp. fetus, and 1.451 Mb for C. laridis. PMID:2168376

  6. Chemotaxis: Under Agarose Assay.

    PubMed

    Brazill, Derrick

    2016-01-01

    The unicellular eukaryote Dictyostelium discoideum represents a superb model for examining chemotaxis. Under vegetative conditions, the amoebae are chemotactically responsive to pterins, such as folate. Under starved conditions, they lose their sensitivity to pterins, and become chemotactically responsive to cAMP. As an NIH model system, Dictyostelium offers a variety of advantages in studying chemotaxis, including its conservation of mammalian signaling pathways, its ease of growth, and its genetic tractability. In this chapter, we describe the use of the under agarose chemotaxis assay to identify proteins involved in controlling motility and directional sensing in Dictyostelium discoideum. Given the similarities between Dictyostelium and mammalian cells, this allows us to dissect the conserved pathways involved in eukaryotic chemotaxis. PMID:26498795

  7. Graphene oxide based sol-gel stainless steel fiber for the headspace solid-phase microextraction of organophosphate ester flame retardants in water samples.

    PubMed

    Jin, Tingting; Cheng, Jing; Cai, Cuicui; Cheng, Min; Wu, Shiju; Zhou, Hongbin

    2016-07-29

    In this paper, graphene oxide was coated onto a stainless steel wire through sol-gel technique and it was used as a solid phase microextraction (SPME) fiber. The prepared fiber was characterized by scanning electron microscopy (SEM), which displayed that the fiber had crinkled surface and porous structure The application of the fiber was evaluated through the headspace SPME of nine organophosphate ester flame retardants (OPFRs) with different characteristics in water samples followed by gas chromatography and nitrogen-phosphorous detector (GC/NPD). The major factors influencing the extraction efficiency, including the extraction and desorption conditions, were studied and optimized. Under the optimum conditions, the proposed method was evaluated, and applied to the analysis of organophosphate ester flame retardants in real environmental water samples. The results demonstrated the HS-SPME method based on GO sol-gel fiber had good linearity (R>0.9928), and limits of detection (1.4-135.6ngL(-1)), high repeatability (RSD<9.8%) and good recovery (76.4-112.4%). The GO based sol-gel fiber displayed bigger extraction capability than the commercial PDMS fiber and the pure sol-gel fiber for both polar and apolar organophosphate esters, especially for the OPFRs containing benzene rings. PMID:27371020

  8. Removal of digoxin from plasma using monoclonal anti-digoxin antibodies immobilized on agarose

    SciTech Connect

    Brizgys, M.; Pincus, S.; Rollins, D.E.

    1986-05-01

    Monoclonal anti-digoxin antibodies (dig-Ab) have been covalently coupled to agarose supports to evaluate them as part of an extracorporeal device for removal of digoxin from the circulation. The agarose supports studied were Sepharose CL-6B, agarose-polyacrolein microsphere (APAM) beads, Bio Gel A-5m and Affi-gel 15 (Bio-Rad). Antibody concentrations between 2 and 4 mg/g gel were coupled to the agarose beads which were then placed in glass columns. Bovine ..cap alpha..-globulin coupled to the agarose supports was used as a control. Binding capacity and affinity of the immobilized antibody were determined by perfusing the dig-Ab agarose beads with a plasma solution containing /sup 3/H-digoxin and various concentrations of digoxin. The binding capacity of the immobilized dig-Ab was 30% of the theoretical value for Sepharose, Bio Gel and Affigel, and 10% of the theoretical value for dig-Ab coupled to APAM beads. The affinity of the immobilized dig-Ab was 10-100 fold less than non-immobilized Ab (3.4 x 10/sup 8/M/sup -1/. The APAM beads showed a significant decrease in binding of digoxin as the flow rate was increased from 0.5 to 5.0 ml/min. These data demonstrate that dig-Ab coupled to agarose and incorporated into a column can be used to remove digoxin from plasma in vitro.

  9. Preparation of Compact Agarose Cell Blocks from the Residues of Liquid-Based Cytology Samples

    PubMed Central

    Choi, Suk Jin; Choi, Yeon Il; Kim, Lucia; Park, In Suh; Han, Jee Young; Kim, Joon Mee; Chu, Young Chae

    2014-01-01

    Background Inevitable loss of diagnostic material should be minimized during cell block preparation. We introduce a modified agarose cell block technique that enables the synthesis of compact cell blocks by using the entirety of a cell pellet without the loss of diagnostic material during cell block preparations. The feasibility of this technique is illustrated by high-throughput immunocytochemistry using high-density cell block microarray (CMA). Methods The cell pellets of Sure- Path residues were pre-embedded in ultra-low gelling temperature agarose gel and re-embedded in standard agarose gel. They were fixed, processed, and embedded in paraffin using the same method as tissue sample processing. The resulting agarose cell blocks were trimmed and represented on a CMA for high-throughput analysis using immunocytochemical staining. Results The SurePath residues were effectively and entirely incorporated into compact agarose cell buttons and embedded in paraffin. Sections of the agarose cell blocks revealed cellularities that correlated well with corresponding SurePath smears and had immunocytochemical features that were sufficient for diagnosis of difficult cases. Conclusions This agarose-based compact cell block technique enables preparation of high-quality cell blocks by using up the residual SurePath samples without loss of diagnostic material during cell block preparation. PMID:25366070

  10. A microfluidic device for on-chip agarose microbead generation with ultralow reagent consumption

    PubMed Central

    Desbois, Linda; Padirac, Adrien; Kaneda, Shohei; Genot, Anthony J.; Rondelez, Yannick; Hober, Didier; Collard, Dominique; Fujii, Teruo

    2012-01-01

    Water-in-oil microdroplets offer microreactors for compartmentalized biochemical reactions with high throughput. Recently, the combination with a sol-gel switch ability, using agarose-in-oil microdroplets, has increased the range of possible applications, allowing for example the capture of amplicons in the gel phase for the preservation of monoclonality during a PCR reaction. Here, we report a new method for generating such agarose-in-oil microdroplets on a microfluidic device, with minimized inlet dead volume, on-chip cooling, and in situ monitoring of biochemical reactions within the gelified microbeads. We used a flow-focusing microchannel network and successfully generated agarose microdroplets at room temperature using the “push-pull” method. This method consists in pushing the oil continuous phase only, while suction is applied to the device outlet. The agarose phase present at the inlet is thus aspirated in the device, and segmented in microdroplets. The cooling system consists of two copper wires embedded in the microfluidic device. The transition from agarose microdroplets to microbeads provides additional stability and facilitated manipulation. We demonstrate the potential of this method by performing on-chip a temperature-triggered DNA isothermal amplification in agarose microbeads. Our device thus provides a new way to generate microbeads with high throughput and no dead volume for biochemical applications. PMID:24106525

  11. A microfluidic device for on-chip agarose microbead generation with ultralow reagent consumption.

    PubMed

    Desbois, Linda; Padirac, Adrien; Kaneda, Shohei; Genot, Anthony J; Rondelez, Yannick; Hober, Didier; Collard, Dominique; Fujii, Teruo

    2012-01-01

    Water-in-oil microdroplets offer microreactors for compartmentalized biochemical reactions with high throughput. Recently, the combination with a sol-gel switch ability, using agarose-in-oil microdroplets, has increased the range of possible applications, allowing for example the capture of amplicons in the gel phase for the preservation of monoclonality during a PCR reaction. Here, we report a new method for generating such agarose-in-oil microdroplets on a microfluidic device, with minimized inlet dead volume, on-chip cooling, and in situ monitoring of biochemical reactions within the gelified microbeads. We used a flow-focusing microchannel network and successfully generated agarose microdroplets at room temperature using the "push-pull" method. This method consists in pushing the oil continuous phase only, while suction is applied to the device outlet. The agarose phase present at the inlet is thus aspirated in the device, and segmented in microdroplets. The cooling system consists of two copper wires embedded in the microfluidic device. The transition from agarose microdroplets to microbeads provides additional stability and facilitated manipulation. We demonstrate the potential of this method by performing on-chip a temperature-triggered DNA isothermal amplification in agarose microbeads. Our device thus provides a new way to generate microbeads with high throughput and no dead volume for biochemical applications. PMID:24106525

  12. Injectable Amorphous Chitin-Agarose Composite Hydrogels for Biomedical Applications

    PubMed Central

    Priya, Murali Vishnu; Kumar, Rajendran Arun; Sivashanmugam, Amirthalingam; Nair, Shantikumar Vasudevan; Jayakumar, Rangasamy

    2015-01-01

    Injectable hydrogels are gaining popularity as tissue engineering constructs because of their ease of handling and minimal invasive delivery. Making hydrogels from natural polymers helps to overcome biocompatibility issues. Here, we have developed an Amorphous Chitin (ACh)-Agarose (Agr) composite hydrogel using a simpletechnique. Rheological studies, such as viscoelastic behavior (elastic modulus, viscous modulus, yield stress, and consistency), inversion test, and injectability test, were carried out for different ACh-Agr concentrations. The composite gel, having a concentration of 1.5% ACh and 0.25% Agr, showed good elastic modulus (17.3 kPa), yield stress (3.8 kPa), no flow under gravity, injectability, and temperature stability within the physiological range. Based on these studies, the optimum concentration for injectability was found to be 1.5% ACh and 0.25% Agr. This optimized concentration was used for further studies and characterized using FT-IR and SEM. FT-IR studies confirmed the presence of ACh and Agr in the composite gel. SEM results showed that the lyophilized composite gel had good porosity and mesh like networks. The cytocompatibility of the composite gel was studied using human mesenchymal stem cells (hMSCs). The composite gels showed good cell viability.These results indicated that this injectable composite gel can be used for biomedical applications. PMID:26308065

  13. Sequence Dependent Electrophoretic Separations of DNA in Pluronic F127 Gels

    NASA Astrophysics Data System (ADS)

    You, Seungyong; van Winkle, David H.

    2010-03-01

    Two-dimensional (2-D) electrophoresis has successfully been used to visualize the separation of DNA fragments of the same length. We electrophorese a double-stranded DNA ladder in an Agarose gel for the first dimension and in gels of Pluronic F127 for the second dimension at room temperature. The 1000 bp band that travels together as a single band in an Agarose gel is split into two bands in Pluronic gels. The slower band follows the exponential decay trend that the other ladder constituents do. After sequencing the DNA fragments, the faster band has an apparently random sequence, while the slower band and the others have two A-tracts in each 250 bp segment. The A-tracts consist of a series of at least five adenine bases pairing with thymine bases. This result leads to the conclusion that the migration of the DNA molecules bent with A-tracts is more retarded in Pluronic gels than the wild-type of DNA molecules.

  14. Maintenance of biological activity of pertussis toxin radioiodinated while bound to fetuin-agarose

    SciTech Connect

    Armstrong, G.D.; Peppler, M.S.

    1987-05-01

    We developed a method to produce radioiodinated pertussis toxin (PT) which was active in the goose erythrocyte agglutination and CHO cell assay systems. The procedure used fetuin coupled to agarose to prevent inactivation of the toxin during the iodination reaction. Analysis of the labeled PT by affinity chromatography on fetuin-agarose and wheat germ agglutinin-agarose and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that there were minimal amounts of labeled fetuin or other contaminants in the labeled PT preparations. All five of the subunits of the toxin appeared to be labeled by the procedure. The labeling method will facilitate further investigations into the nature of the interaction and activity of PT in host tissues.

  15. Maintenance of biological activity of pertussis toxin radioiodinated while bound to fetuin-agarose.

    PubMed Central

    Armstrong, G D; Peppler, M S

    1987-01-01

    We developed a method to produce radioiodinated pertussis toxin (PT) which was active in the goose erythrocyte agglutination and CHO cell assay systems. The procedure used fetuin coupled to agarose to prevent inactivation of the toxin during the iodination reaction. Analysis of the labeled PT by affinity chromatography on fetuin-agarose and wheat germ agglutinin-agarose and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that there were minimal amounts of labeled fetuin or other contaminants in the labeled PT preparations. All five of the subunits of the toxin appeared to be labeled by the procedure. The labeling method will facilitate further investigations into the nature of the interaction and activity of PT in host tissues. Images PMID:2437034

  16. Crosslinking of agarose bioplastic using citric acid.

    PubMed

    Awadhiya, Ankur; Kumar, David; Verma, Vivek

    2016-10-20

    We report chemical crosslinking of agarose bioplastic using citric acid. Crosslinking was confirmed using Fourier transform infrared (FTIR) spectroscopy. The effects of crosslinking on the tensile strength, swelling, thermal stability, and degradability of the bioplastic were studied in detail. The tensile strength of the bioplastic films increased from 25.1MPa for control films up to a maximum of 52.7MPa for citric acid crosslinked films. At 37°C, the amount of water absorbed by crosslinked agarose bioplastic was only 11.5% of the amount absorbed by non-crosslinked controls. Thermogravimetric results showed that the crosslinked samples retain greater mass at high temperature (>450°C) than control samples. Moreover, while the crosslinked films were completely degradable, the rate of degradation was lower compared to non-crosslinked controls. PMID:27474543

  17. Mental Retardation.

    ERIC Educational Resources Information Center

    Baumeister, Alfred A., Ed.

    Thirteen papers by different authors consider the application of research findings and theoretical formulations to the practical appraisal and treatment of mental retardation. All suggest methods for shaping appropriate and adaptive behaviors in retarded individuals. The papers include "Definition, Diagnosis, and Classification" by D.W. Brison,…

  18. Mental Retardation.

    ERIC Educational Resources Information Center

    Purpura, Dominick P.; And Others

    Evidence today indicates that the causes of mental retardation are biological, psychological, and social in origin and that a combination of these causes frequently occur in a single individual. Mental retardation is identified clinically by the presence of several signs that include, but are not limited to, a significant impairment of…

  19. Tuning mechanical performance of poly(ethylene glycol) and agarose interpenetrating network hydrogels for cartilage tissue engineering

    PubMed Central

    Rennerfeldt, DA; Renth, AN; Talata, Z; Gehrke, SH; Detamore, MS

    2013-01-01

    Hydrogels are attractive for tissue engineering applications due to their incredible versatility, but they can be limited in cartilage tissue engineering applications due to inadequate mechanical performance. In an effort to address this limitation, our team previously reported the drastic improvement in the mechanical performance of interpenetrating networks (IPNs) of poly(ethylene glycol) diacrylate (PEG-DA) and agarose relative to pure PEG-DA and agarose networks. The goal of the current study was specifically to determine the relative importance of PEG-DA concentration, agarose concentration, and PEG-DA molecular weight in controlling mechanical performance, swelling characteristics, and network parameters. IPNs consistently had compressive and shear moduli greater than the additive sum of either single network when compared to pure PEG-DA gels with a similar PEG-DA content. IPNs withstood a maximum stress of up to 4.0 MPa in unconfined compression, with increased PEG-DA molecular weight being the greatest contributing factor to improved failure properties. However, aside from failure properties, PEG-DA concentration was the most influential factor for the large majority of properties. Increasing the agarose and PEG-DA concentrations as well as the PEG-DA molecular weight of agarose/PEG-DA IPNs and pure PEG-DA gels improved moduli and maximum stresses by as much as an order of magnitude or greater compared to pure PEG-DA gels in our previous studies. Although the viability of encapsulated chondrocytes was not significantly affected by IPN formulation, glycosaminoglycan (GAG) content was significantly influenced, with a 12-fold increase over a three-week period in gels with a lower PEG-DA concentration. These results suggest that mechanical performance of IPNs may be tuned with partial but not complete independence from biological performance of encapsulated cells. PMID:23932504

  20. Effect of gel structure of matrix orientation in pulsed alternating electric fields

    SciTech Connect

    Stellwagen, N.C.; Stellwagen, J.

    1993-12-31

    Four polymeric gels with different structures, LE agarose, HEEO agarose, beta-carrageenan, and polyacrylamide, were studied by transient electric birefringence to determine the importance of various structural features on the orientation of the gels in pulsed alternating electric fields. The birefrigence relaxation times observed for agarose gels in low voltage electric fields suggest that long fibers and/or domains, ranging up to tens of microns in size, are oriented by the electric field. The sign of the birefringence reverses when the direction of the electric field is reversed, suggesting that the oriented domains change their direction of orientation from parallel to perpendicular (or vice versa) when the polarity of the electric field is reversed. These anamalous orientation effects are observed with both types of agarose gels, but not with beta-carrageenan or polyacrylamide gels, suggesting that the alternating D,L galactose residues in the agarose backbone are responsible for the anomalies.

  1. Rheological Characterization of Ethanolamine Gel Propellants

    NASA Astrophysics Data System (ADS)

    V. S Jyoti, Botchu; Baek, Seung Wook

    2016-07-01

    Ethanolamine is considered to be an environmentally friendly propellant system because it has low toxicity and is noncarcinogenic in nature. In this article, efforts are made to formulate and prepare ethanolamine gel systems, using pure agarose and hybrids of paired gelling agents (agarose + polyvinylpyrrolidine (PVP), agarose + SiO2, and PVP + SiO2), that exhibit a measurable yield stress, thixotropic behavior under shear rate ranges of 1-1,000 s-1 and a viscoelastic nature. To achieve these goals, multiple rheological experiments (including flow and dynamic studies) are performed. In this article, results are presented from experiments measuring the apparent viscosity, yield stress, thixotropy, dynamic strain, frequency sweep, and tan δ behaviors, as well as the effects of the test temperature, in the gel systems. The results show that the formulated ethanolamine gels are thixotropic in nature with yield stress between 30 and 60 Pa. The apparent viscosity of the gel decreases as the test temperature increases, and the apparent activation energy is the lowest for the ethanolamine-(PVP + SiO2) gel system. The dynamic rheology study shows that the type of gellant, choice of hybrid gelling materials and their concentration, applied frequencies, and strain all vitally affect the viscoelastic properties of the ethanolamine gel systems. In the frequency sweep experiment, the ethanolamine gels to which agarose, agarose + PVP, and agarose + SiO2 were added behave like linear frequency-dependent viscoelastic liquids, whereas the ethanolamine gel to which PVP + SiO2 was added behaves like a nearly frequency-independent viscoelastic solid. The variation in the tan δ of these gelled propellants as a function of frequency is also discussed.

  2. Flame retardants

    NASA Technical Reports Server (NTRS)

    Troitzsch, J.

    1988-01-01

    The use of flame retardants in plastics has grown only slightly in recent years and will probably grow slowly in the future. The reasons for this are slow economic growth and the absence of fundamentally new requirements for future fire prevention. The trends are toward the increasing use of easily handled, dust-free and well-dispersed flame retardant compounds and master batches; there are no spectacular new developments. In the future, questions of smoke evolution, toxicity and corrosiveness of combustion gases will become increasingly important, especially due to new regulations and rising requirements for environmental protection.

  3. In Situ Observations of Thermoreversible Gelation and Phase Separation of Agarose and Methylcellulose Solutions under High Pressure.

    PubMed

    Kometani, Noritsugu; Tanabe, Masahiro; Su, Lei; Yang, Kun; Nishinari, Katsuyoshi

    2015-06-01

    Thermoreversible sol-gel transitions of agarose and methylcellulose (MC) aqueous solutions on isobaric cooling or heating under high pressure up to 400 MPa have been investigated by in situ observations of optical transmittance and falling-ball experiments. For agarose, which undergoes the gelation on cooling, the application of pressure caused a gradual rise in the cloud-point temperature over the whole pressure range examined, which is almost consistent with the pressure dependence of gelling temperature estimated by falling-ball experiments, suggesting that agarose gel is stabilized by compression and that the gelation occurs nearly in parallel with phase separation under ambient and high-pressure conditions. For MC, which undergoes the gelation on heating, the cloud-point temperature showed a slight rise with an initial elevation of pressure up to ∼150 MPa, whereas it showed a marked depression above 200 MPa. In contrast, the gelling temperature of MC, which is nearly identical to the cloud-point temperature at ambient pressure, showed a monotonous rise with increasing pressure up to 350 MPa, which means that MC undergoes phase separation prior to gelation on heating under high pressure above 200 MPa. Similar results were obtained for the melting process of MC gel on cooling. The unique behavior of the sol-gel transition of MC under high pressure has been interpreted in terms of the destruction of hydrophobic hydration by compression. PMID:25984597

  4. Biohybrid Carbon Nanotube/Agarose Fibers for Neural Tissue Engineering

    PubMed Central

    Lewitus, Dan Y.; Landers, John; Branch, Jonathan; Smith, Karen L.; Callegari, Gerardo

    2011-01-01

    We report a novel approach for producing carbon nanotube fibers (CNF) composed with the polysaccharide agarose. Current attempts to make CNF’s require the use of a polymer or precipitating agent in the coagulating bath that may have negative effects in biomedical applications. We show that by taking advantage of the gelation properties of agarose one can substitute the bath with distilled water or ethanol and hence reduce the complexity associated with alternating the bath components or the use of organic solvents. We also demonstrate that these CNF can be chemically functionalized to express biological moieties through available free hydroxyl groups in agarose. We corroborate that agarose CNF are not only conductive and nontoxic, but their functionalization can facilitate cell attachment and response both in vitro and in vivo. Our findings suggest that agarose/CNT hybrid materials are excellent candidates for applications involving neural tissue engineering and biointerfacing with the nervous system. PMID:21887125

  5. Preparation of uniform-sized agarose beads by microporous membrane emulsification technique.

    PubMed

    Zhou, Qing-Zhu; Wang, Lian-Yan; Ma, Guang-Hui; Su, Zhi-Guo

    2007-07-01

    Uniform-sized agarose beads were prepared by membrane emulsification technique in this study. Agarose was dissolved in boiling water (containing 0.9% sodium chloride) and used as water phase. A mixture of liquid paraffin and petroleum ether containing 4 wt% of hexaglycerin penta ester (PO-500) emulsifier was used as oil phase. At 55 degrees C, the water phase permeated through uniform pores of microporous membrane into the oil phase by a pressure of nitrogen gas to form uniform W/O emulsion. Then the emulsion was cooled down to room temperature under gentle agitation to form gel beads. The effect of oil phase, emulsifier, especially temperature on the uniformity of the beads were investigated and interpreted from interfacial tension between water phase and oil phase. Under optimized condition, the coefficient variation (C.V.) showing the size distribution of the beads was under 15%. This was the first report to prepare uniform agarose beads by membrane emulsification, and to investigate the effect of temperature on the size distribution of the droplets and beads. The beads with different size can be prepared by using membranes with different pore size, and the result showed that there was a linear relationship between the average diameter of beads and pore size of the membranes; beads with diameter from 15 to 60 microm were able to obtain in this study. PMID:17362974

  6. Agarose particle-templated porous bacterial cellulose and its application in cartilage growth in vitro.

    PubMed

    Yin, Na; Stilwell, Matthew D; Santos, Thiago M A; Wang, Huaping; Weibel, Douglas B

    2015-01-01

    Bacterial cellulose (BC) is a biocompatible hydrogel with a three-dimensional (3-D) structure formed by a dense network of cellulose nanofibers. A limitation of using BC for applications in tissue engineering is that the pore size of the material (∼0.02-10μm) is smaller than the dimensions of mammalian cells and prevents cells from penetrating into the material and growing into 3-D structures that mimic tissues. This paper describes a new route to porous bacterial cellulose (pBC) scaffolds by cultivating Acetobacter xylinum in the presence of agarose microparticles deposited on the surface of a growing BC pellicle. Monodisperse agarose microparticles with a diameter of 300-500μm were created using a microfluidic technique, layered on growing BC pellicles and incorporated into the polymer as A. xylinum cells moved upward through the growing pellicle. Removing the agarose microparticles by autoclaving produced BC gels containing a continuous, interconnected network of pores with diameters ranging from 300 to 500μm. Human P1 chondrocytes seeded on the scaffolds, replicated, invaded the 3-D porous network and distributed evenly throughout the substrate. Chondrocytes grown on pBC substrates displayed a higher viability compared to growth on the surface of unmodified BC substrates. The approach described in this paper introduces a new method for creating pBC substrates with user-defined control over the physical dimensions of the pore network, and demonstrates the application of these materials for tissue engineering. PMID:25449918

  7. Oxidized dextrins as alternative crosslinking agents for polysaccharides: application to hydrogels of agarose-chitosan.

    PubMed

    Gómez-Mascaraque, Laura G; Méndez, José Alberto; Fernández-Gutiérrez, Mar; Vázquez, Blanca; San Román, Julio

    2014-02-01

    Hydrogel networks that combine suitable physical and biomechanical characteristics for tissue engineering scaffolds are in demand. The aim of this work was the development of hydrogel networks based on agarose and chitosan using oxidized dextrins as low cytotoxicity crosslinking agents, paying special attention to the study of the influence of the polysaccharide composition and oxidation degree of the dextrins in the final characteristics of the network. The results show that the formation of an interpenetrating or a semi-interpenetrating polymer network was mainly dependent on a minimum agarose content and degree of oxidation of dextrin. Spectroscopic, thermal and swelling analysis revealed good compatibility with an absence of phase separation of polysaccharides at agarose:chitosan proportions of 50:50 and 25:75. The analysis of atomic force microscopy images showed the formation of a fibrillar microstructure whose distribution within the crosslinked chitosan depended mainly on the crosslinker. All materials exhibited the viscoelastic behaviour typical of gels, with a constant storage modulus independent of frequency for all compositions. The stiffness was strongly influenced by the degree of oxidation of the crosslinker. Cellular response to the hydrogels was studied with cells of different strains, and cell adhesion and proliferation was correlated with the homogeneity of the samples and their elastic properties. Some hydrogel formulations seemed to be candidates for tissue engineering applications such as wound healing or soft tissue regeneration. PMID:24121253

  8. Influence of gelling agents on the dosimetric performance of the Turnbull Blue gel dosimeter

    NASA Astrophysics Data System (ADS)

    Šolc, Jaroslav; Sochor, Vladimír; Spěváček, Václav

    2010-11-01

    Gelling agents such as agarose, phytagel, and several types of gelatin were used for preparation of Turnbull Blue radiochromic gel dosimeter. Their influence on gel dose response and background value was assessed. It was found that all gelatins cause significant increase of background in a short period of time after gel preparation therefore gelatin is not a suitable gelling agent for this dosimeter. Phytagel and agarose gels exhibit low and stable background and higher dose sensitivity than gelatin gels; however, the disadvantage is increased scattered light intensity in the gel in comparison to gelatin gels. A simple measurement was done demonstrating that the scattered light intensity significantly increases in phytagel and agarose gel in comparison to gelatin gels.

  9. Estradiol receptor of calf uterus: interactions with heparin-agarose and purification.

    PubMed Central

    Molinari, A M; Medici, N; Moncharmont, B; Puca, G A

    1977-01-01

    Heparin attached covalently to agarose beads binds the "native" form of the estradiol receptor with very high affinity. Chondroitin sulfate does not bind to the receptor. When the receptor is complexed with hormone, the affinity is at least 10 times higher. Only the "native" and not the "nuclear" or the "derived" (i.e., after activation by a calcium-dependent enzyme) forms of the estradiol receptor interact with heparin. The "native" estradiol-receptor complex is purified to homogeneity after chromatography on columns of heparin-agarose, Sephadex G-200, and DEAE-cellulose, followed by two more Sephadex G-200 columns. The purified molecule is a single polypeptide of molecular weight 69,000 by polyacrylamide gel electrophoresis in sodium dodecyl sulphate. The sedimentation coefficient on sucrose gradients is 4.3 S, the Stokes radius from gel filtration is 36.5 A, and the isoelectric point is 6.4. The purified [3H]estradiol-receptor complex exchanges the radioactive hormone with estradiol or other estrogenic steroids, but not with testosterone, 5alpha-dihydrotestosterone, or progesterone. Images PMID:270721

  10. Augmenting Protein Release from Layer- by-Layer Functionalized Agarose Hydrogels

    PubMed Central

    Lynam, Daniel; Peterson, Chelsea; Maloney, Ryan; Shahriari, Dena; Garrison, Alexa; Saleh, Sara; Mehrotra, Sumit; Chan, Christina; Sakamoto, Jeff

    2014-01-01

    Recent work demonstrated the efficacy of combining layer-by-layer assembly with hydrogels to provide the controlled delivery of proteins for use in nerve repair scaffolds. In this work, we augmented the protein dose response by controlling and increasing the hydrogel internal surface area. Sucrose was added to agarose during gelation to homogenize the nanopore morphology, resulting in increased surface area per unit volume of hydrogel. The surface area of a range of compositions (1.5 to 5.0 wt% agarose and 0, 50 and 65 wt% sucrose) was measured. Gels were supercritically dried to preserve porosity enabling detailed pore morphology measurements using nitrogen adsorption and high resolution scanning electron microscopy. The resulting surface area, normalized by superficial gel volume, ranged between 6 and 56m2/ccgel. Using the layer-by-layer process to load lysozyme, a neurotrophic factor analog, a relationship was observed between surface area and cumulative dose response ranging from 176 to 2556 μg/mL, which is in the range of clinical relevance for the delivery of growth factors. In this work, we demonstrated that the ability to control porosity is key in tuning drug delivery dose response from layer-by-layer modified hydrogels. PMID:24528743

  11. Drop spreading and resorbtion on gel surfaces

    NASA Astrophysics Data System (ADS)

    Banaha, Mehdi; Daerr, Adrian; Limat, Laurent

    2008-03-01

    We have studied the dynamics of liquid drops on agar gels, using a visualisation method which captures the evolution of the free surface. A first remarquable observation is that drops of water deposited on the surface do not spread, although the gel consists of up to 99.7% water and as low as 0.3% agarose. Instead, the drop slowly de-wets and resorbs into the gel which swells locally. If the deposited drop contains surfactants, the dynamics is very different. A sharp circular swelling front develops and progressively invades the whole surface. We study the propagation of this front as a function of surfactant and agarose concentration, and compare its typical properties to similar fronts appearing during mass swarming events of bacterial colonies under the same conditions. The observations reveal the complex nature of gel surface physico-chemistry and its aging, and may be related to recent friction measurements at gel interfaces.

  12. Functionalized Agarose Self-Healing Ionogels Suitable for Supercapacitors.

    PubMed

    Trivedi, Tushar J; Bhattacharjya, Dhrubajyoti; Yu, Jong-Sung; Kumar, Arvind

    2015-10-12

    Agarose has been functionalized (acetylated/carbanilated) in an ionic liquid (IL) medium of 1-butyl-3-methylimidazolium acetate at ambient conditions. The acetylated agarose showed a highly hydrophobic nature, whereas the carbanilated agarose could be dissolved in water as well as in the IL medium. Thermoreversible ionogels were obtained by cooling the IL sols of carbanilated agarose at room temperature. The ionogel prepared from a protic-aprotic mixed-IL system (1-butyl-3-methylimidazolium chloride and N-(2-hydroxyethyl)ammonium formate) demonstrated a superior self-healing property, as confirmed from rheological measurements. The superior self-healing property of such an ionogel has been attributed to the unique inter-intra hydrogen-bonding network of functional groups inserted in the agarose. The ionogel was tested as a flexible solid electrolyte for an activated-carbon-based supercapacitor cell. The measured specific capacitance was found to be comparable with that of a liquid electrolyte system at room temperature and was maintained for up to 1000 charge-discharge cycles. Such novel functionalized-biopolymer self-healing ionogels with flexibility and good conductivity are desirable for energy-storage devices and electronic skins with superior lifespans and robustness. PMID:26280813

  13. Gel Electrophoresis--The Easy Way for Students

    ERIC Educational Resources Information Center

    VanRooy, Wilhelmina; Sultana, Khalida

    2010-01-01

    This article describes a simple, inexpensive, easy to conduct gel-electrophoresis activity using food dyes. It is an alternative to the more expensive counterparts which require agarose gel, DNA samples, purchased chamber and Tris-borate-EDTA buffer. We suggest some learning activities for senior biology students along with comments on several…

  14. Magnetic Hyperthermia in ferrofluid-gel composites

    NASA Astrophysics Data System (ADS)

    Nemala, Humeshkar; Wadehra, Anshu; Dixit, Ambesh; Regmi, Rajesh; Vaishnava, Prem; Lawes, Gavin; Naik, Ratna

    2012-02-01

    Magnetic hyperthermia is the generation of heat by an external magnetic field using superparamagnetic nanoparticles. However, there are still questions concerning magnetic hyperthermia in tissue; in particular the confinement of the nanoparticles at mesoscopic scales. We used Agarose and Alginate gels as models for human tissue and embedded magnetic nanoparticles in them. We report the synthesis and characterization of dextran coated iron oxide (Fe3O4) nanoparticles. Characterization of these nanoparticles was done using X-ray diffraction, transmission electron microscopy, magnetometry, and hyperthermia measurements. Temperature dependent susceptibility measurements reveal a sharp anomaly in the ferrofluid sample at the freezing temperature. This is conspicuously absent in the ferrofluid-gel composites. Heat generation studies on these superparamagnetic gel-composites revealed a larger heat production in the ferrofluids(˜4W/g) as compared to the gels(˜1W/g), which we attribute to a reduction in Brownian relaxation for the nanoparticles embedded in Agarose and Alginate.

  15. Electrophoretic extraction of proteins from two-dimensional electrophoresis gel spots

    DOEpatents

    Zhang, Jian-Shi; Giometti, C.S.; Tollaksen, S.L.

    1987-09-04

    After two-dimensional electrophoresis of proteins or the like, resulting in a polyacrylamide gel slab having a pattern of protein gel spots thereon, an individual protein gel spot is cored out from the slab, to form a gel spot core which is placed in an extraction tube, with a dialysis membrane across the lower end of the tube. Replicate gel spots can be cored out from replicate gel slabs and placed in the extraction tube. Molten agarose gel is poured into the extraction tube where the agarose gel hardens to form an immobilizing gel, covering the gel spot cores. The upper end portion of the extraction tube is filled with a volume of buffer solution, and the upper end is closed by another dialysis membrane. Upper and lower bodies of a buffer solution are brought into contact with the upper and lower membranes and are provided with electrodes connected to the positive and negative terminals of a dc power supply, thereby producing an electrical current which flows through the upper membrane, the volume of buffer solution, the agarose, the gel spot cores and the lower membrane. The current causes the proteins to be extracted electrophoretically from the gel spot cores, so that the extracted proteins accumulate and are contained in the space between the agarose gel and the upper membrane. 8 figs.

  16. Porous ceramic/agarose composite adsorbents for fast protein liquid chromatography.

    PubMed

    Xia, Haifeng; Jin, Xionghua; Wu, Puqiang; Zheng, Zhiyong

    2012-02-01

    Porous ceramic/agarose composite adsorbents were designed and prepared with silica ceramic beads and 4% agarose gel, and then functionalized with a special ligand carboxymethyl. A novel method was introduced to fabricating of the porous silica ceramic beads. The morphology of SEM shows a spherical shape and a porous structure of the ceramic beads. Nitrogen adsorption-desorption analysis gives an average pore size of 287.5 Å, a BET surface area of 29.33 m²/g and a porosity of 41.8%, respectively. Additionally, X-ray diffraction pattern indicates that the amorphous silica has been transformed into two crystal phases of quartz and cristobalite, leading to a porous and rigid skeleton and ensuring the application of the composite beads at high flow velocities. Lysozyme of hen egg-white with the activity of 12,700 U/mg was purified by the composite ion-exchanger in one step and the recovery and purification factor reaches 95.2% and 7.9, respectively. PMID:22226554

  17. Production of cell-enclosing hollow-core agarose microcapsules via jetting in water-immiscible liquid paraffin and formation of embryoid body-like spherical tissues from mouse ES cells enclosed within these microcapsules.

    PubMed

    Sakai, Shinji; Hashimoto, Ichiro; Kawakami, Koei

    2008-01-01

    We developed agarose microcapsules with a single hollow core templated by alginate microparticles using a jet-technique. We extruded an agarose aqueous solution containing suspended alginate microparticles into a coflowing stream of liquid paraffin and controlled the diameter of the agarose microparticles by changing the flow rate of the liquid paraffin. Subsequent degradation of the inner alginate microparticles using alginate lyase resulted in the hollow-core structure. We successfully obtained agarose microcapsules with 20-50 microm of agarose gel layer thickness and hollow cores ranging in diameter from ca. 50 to 450 microm. Using alginate microparticles of ca. 150 microm in diameter and enclosing feline kidney cells, we were able to create cell-enclosing agarose microcapsules with a hollow core of ca. 150 microm in diameter. The cells in these microcapsules grew much faster than those in alginate microparticles. In addition, we enclosed mouse embryonic stem cells in agarose microcapsules. The embryonic stem cells began to self-aggregate in the core just after encapsulation, and subsequently grew and formed embryoid body-like spherical tissues in the hollow core of the microcapsules. These results show that our novel microcapsule production technique and the resultant microcapsules have potential for tissue engineering, cell therapy and biopharmaceutical applications. PMID:17705234

  18. Electron Beam Sterilization of the Plates with Agaroze Gel Used for Electrophoresis

    NASA Astrophysics Data System (ADS)

    Ighigeanu, Daniel I.; Martin, Diana I.; Stan, Dana E.; Matei, Constantin I.; Manaila, Elena M.; Craciun, Gabriela D.; Iacob, Nicusor I.; Oproiu, Constantin V.; Ighigeanu, Adelina I.

    2007-04-01

    Electron beam (EB) sterilization applied to the plastic plates with agarose gel used for electrophoresis is presented. The effects of EB irradiation upon the agarose gel and on the process of the proteic fraction separation have been investigated. The investigation were focused on the concentration changes of the six proteic fractions, albumin, alpha 1, alpha 2, beta 1, beta 2 and gamma, versus the dose irradiation as compared with the unirradiated sample.

  19. In-house Manual Construction of High-Density and High-Quality Tissue Microarrays by Using Homemade Recipient Agarose-Paraffin Blocks

    PubMed Central

    Kim, Kyu Ho; Choi, Yeon Il; Kim, Lucia; Park, In Suh; Han, Jee Young; Kim, Joon Mee; Chu, Young Chae

    2013-01-01

    Background Self-made tissue punches can be effectively used to punch holes in blank recipient paraffin blocks and extract tissue cores from the donor paraffin blocks for the low-cost construction of tissue microarrays (TMAs). However, variable degrees of section distortion and loss of the tissue cores can occurs during cutting of the TMAs, posing technical problems for in-house manual construction of high-density TMAs. We aimed to update the method for in-house manual TMA construction to improve the quality of high-density TMAs. Methods Blocks of agarose gel were subjected to the standard tissue processing and embedding procedure to prepare recipient agarose-paraffin blocks. The self-made tissue punches and recipient agarose-paraffin blocks were used to construct TMAs, which were completely melted and re-embedded in paraffin to make finished TMA blocks. Results The donor tissue cores were completely integrated into the surrounding paraffin of the recipient blocks. This method enabled us to construct high-density TMAs with significantly less section distortion or loss of tissue cores during microtomy. Conclusions Simple and inexpensive construction of high-density and high-quality TMAs can be warranted by using paraffinized agarose gels as recipient blocks. PMID:23837016

  20. Two-dimensional differential adherence of neuroblasts in laser micromachined CAD/CAM agarose channels

    NASA Astrophysics Data System (ADS)

    Doraiswamy, A.; Patz, T.; Narayan, R. J.; Dinescu, M.; Modi, R.; Auyeung, R. C. Y.; Chrisey, D. B.

    2006-04-01

    Laser micromachining of hydrophobic gels into CAD/CAM patterns was used to develop differentially adherent surfaces and induce the attachment of B35 rat neuroblasts that would later form engineered nerve bundles. Narrow channels, 60-400 μm wide, were micromachined in a 2% agarose gel using an ArF laser, and subsequently filled with an extracellular matrix gel. Upon the addition of 1 ml of a 2 × 104 cells/ml neuroblast suspension, the cells selectively adhered to the ECM-lined channels in a non-confluent manner and we monitored their growth at various time points. The adherent neuroblasts were fluorescently imaged with a propidium iodide live/dead assay, which revealed that the cells were alive within the channels. After 72 h growth, the neuroblasts grew, proliferated, and differentiated into nerve bundles. The fully grown 1 cm long nerve bundle organoids maintained an aspect ratio on the order of 100. The results presented in this paper provide the foundation for laser micromachining technique to develop bioactive substrates for development of three-dimensional tissues. Laser micromachining offers rapid prototyping of substrates, excellent resolution, control of pattern depth and dimensions, and ease of fabrication.

  1. DNA DAMAGE QUANTITATION BY ALKALINE GEL ELECTROPHORESIS.

    SciTech Connect

    SUTHERLAND,B.M.; BENNETT,P.V.; SUTHERLAND, J.C.

    2004-03-24

    Physical and chemical agents in the environment, those used in clinical applications, or encountered during recreational exposures to sunlight, induce damages in DNA. Understanding the biological impact of these agents requires quantitation of the levels of such damages in laboratory test systems as well as in field or clinical samples. Alkaline gel electrophoresis provides a sensitive (down to {approx} a few lesions/5Mb), rapid method of direct quantitation of a wide variety of DNA damages in nanogram quantities of non-radioactive DNAs from laboratory, field, or clinical specimens, including higher plants and animals. This method stems from velocity sedimentation studies of DNA populations, and from the simple methods of agarose gel electrophoresis. Our laboratories have developed quantitative agarose gel methods, analytical descriptions of DNA migration during electrophoresis on agarose gels (1-6), and electronic imaging for accurate determinations of DNA mass (7-9). Although all these components improve sensitivity and throughput of large numbers of samples (7,8,10), a simple version using only standard molecular biology equipment allows routine analysis of DNA damages at moderate frequencies. We present here a description of the methods, as well as a brief description of the underlying principles, required for a simplified approach to quantitation of DNA damages by alkaline gel electrophoresis.

  2. Introduction to Mental Retardation

    ERIC Educational Resources Information Center

    Arc of the United States, 2004

    2004-01-01

    The purpose of this document is to define mental retardation and answer questions related to this topic. According to the American Association on Mental Retardation (AAMR), mental retardation is a disability that occurs before age 18. It is characterized by significant limitations in intellectual functioning and adaptive behaviors as expressed in…

  3. Agarose and methylcellulose hydrogel blends for nerve regeneration applications

    NASA Astrophysics Data System (ADS)

    Martin, Benton C.; Minner, Eric J.; Wiseman, Sherri L.; Klank, Rebecca L.; Gilbert, Ryan J.

    2008-06-01

    Trauma sustained to the central nervous system is a debilitating problem for thousands of people worldwide. Neuronal regeneration within the central nervous system is hindered by several factors, making a multi-faceted approach necessary. Two factors contributing to injury are the irregular geometry of injured sites and the absence of tissue to hold potential nerve guides and drug therapies. Biocompatible hydrogels, injectable at room temperature, that rapidly solidify at physiological temperatures (37 °C) are beneficial materials that could hold nerve guidance channels in place and be loaded with therapeutic agents to aid wound healing. Our studies have shown that thermoreversible methylcellulose can be combined with agarose to create hydrogel blends that accommodate these properties. Three separate novel hydrogel blends were created by mixing methylcellulose with one of the three different agaroses. Gelation time tests show that the blends solidify at a faster rate than base methylcellulose at 37 °C. Rheological data showed that the elastic modulus of the hydrogel blends rapidly increases at 37 °C. Culturing experiments reveal that the morphology of dissociated dorsal root ganglion neurons was not altered when the hydrogels were placed onto the cells. The different blends were further assessed using dissolution tests, pore size evaluations using scanning electron microscopy and measuring the force required for injection. This research demonstrates that blends of agarose and methylcellulose solidify much more quickly than plain methylcellulose, while solidifying at physiological temperatures where agarose cannot. These hydrogel blends, which solidify at physiological temperatures naturally, do not require ultraviolet light or synthetic chemical cross linkers to facilitate solidification. Thus, these hydrogel blends have potential use in delivering therapeutics and holding scaffolding in place within the nervous system.

  4. Silver nanoparticles doped agarose disk: highly sensitive surface-enhanced Raman scattering substrate for in situ analysis of ink dyes.

    PubMed

    Raza, Ali; Saha, Basudeb

    2013-12-10

    Raman spectroscopy is a preferred analytical tool for forensic trace analysis due to its non-invasive nature. This technique has been utilized in examination of organic colorants present in fibers and ink, but high fluorescent nature of these compounds is a problem. In the present study, silver-doped agarose gel disk, having property of quenching fluorescence and enhancing Raman signals, is found to be effective as surface-enhanced Raman scattering (SERS) substrates for analysis of rhodamine 6G (Rh 6G) and crystal violet (CV) dyes. As-prepared and well characterized by UV, TEM-EDAX and XRD techniques, the investigated silver-doped agarose gel disk proves to have minimal invasive as confirmed by the ATR-FTIR method and effective for in situ SERS analysis of blue and red ballpoint ink. The disk is stable upon storage and hence can be re-used and re-examined. The present method offers new possibilities in trace forensic analysis with minimal destruction. PMID:24314497

  5. Binding of glycosaminoglycans to cyano-activated agarose membranes: kinetic and diffusional effects on yield and homogeneity.

    PubMed

    Mattern, Kristin J; Deen, William M

    2007-11-01

    Methods were developed for binding a glycosaminoglycan (GAG, a 50 kDa chondroitin sulfate) to thin agarose membranes using 1-cyano-4-(dimethylamino)pyridinium tetrafluoroborate (CDAP) as the activating agent. Process conditions were optimized to achieve high yields and spatially uniform concentrations of bound ligand. Yields were varied mainly by manipulating the duration and temperature of the aqueous washes prior to coupling, which affected the concentration of active sites available for subsequent GAG binding. The rate constants for degradation of the active cyanate esters in 0.1M bicarbonate solutions were 0.24+/-0.02 h(-1) at 4 degrees C and 0.08+/-0.03 h(-1) at 0 degrees C. Steric limitations in the 3% agarose gels severely restricted binding, with only about 0.1% of active sites being accessible to GAG molecules. The GAG binding occurred primarily in the outer 50-70 microm of the membranes, so that coupling was homogeneous only for thin gels. A model of GAG diffusion and reaction in the coupling step was developed to explain the observed effects of parameters such as the GAG concentration in solution and the membrane thickness. An analysis of the key time scales in the synthesis provides design principles that should be useful also for other cyanylating agents, other ligands, and for beads as well as membranes. PMID:17610855

  6. Enzymatic production of 3,6-anhydro-L-galactose from agarose and its purification and in vitro skin whitening and anti-inflammatory activities.

    PubMed

    Yun, Eun Ju; Lee, Saeyoung; Kim, Ji Hye; Kim, Bo Bae; Kim, Hee Taek; Lee, Sun Hee; Pelton, Jeffrey G; Kang, Nam Joo; Choi, In-Geol; Kim, Kyoung Heon

    2013-04-01

    3,6-Anhydro-L-galactose (L-AHG) constitutes 50% of agarose, which is the main component of red macroalgae. No information is currently available on the mass production, metabolic fate, or physiological effects of L-AHG. Here, agarose was converted to L-AHG in the following three steps: pre-hydrolysis of agarose into agaro-oligosaccharides by using acetic acid, hydrolysis of the agaro-oligosaccharides into neoagarobiose by an exo-agarase, and hydrolysis of neoagarobiose into L-AHG and galactose by a neoagarobiose hydrolase. After these three steps, L-AHG was purified by adsorption and gel permeation chromatographies. The final product obtained was 95.6% pure L-AHG at a final yield of 4.0% based on the initial agarose. In a cell proliferation assay, L-AHG at a concentration of 100 or 200 μg/ mL did not exhibit any significant cytotoxicity. In a skin whitening assay, 100 μg/ mL of L-AHG showed significantly lower melanin production compared to arbutin. L-AHG at 100 and 200 μg/ mL showed strong anti-inflammatory activity, indicating the significant suppression of nitrite production. This is the first report on the production of high-purity L-AHG and its physiological activities. PMID:22678025

  7. Separation of human IgG fragments using copper, nickel, zinc, and cobalt chelated to CM-Asp-agarose by positive and negative chromatography.

    PubMed

    Mourão, Cecília Alves; Carmignotto, Gabriela Pannunzio; Bueno, Sonia Maria Alves

    2016-04-01

    This study evaluated the feasibility of using immobilized metal-ion affinity chromatography (IMAC) for separation of human Fab fragments using four different transition metal ions copper, nickel, zinc, and cobalt chelated to CM-Asp (carboxymethylaspartate) immobilized on the agarose gel. The Fab and Fc fragments (from human IgG digested with papain) interacted differently with the chelates studied, depending on the adsorption buffer system. The interaction between chelate and Fc fragment is predominantly based on the coordination bonds using adsorption buffer containing NaCl. Negative chromatography was performed on Cu(II)-CM-Asp-agarose obtaining 2.9mg of Fab per mL of adsorbent in nonretained fractions (Fc fragment-free without uncleaved IgG). The adsorption of Fab fragments is governed by electrostatic forces in the absence of NaCl in the adsorption buffer. High selectivity was achieved on Co(II)-CM-Asp-agarose and 5.7mg of Fab per mL of adsorbent was obtained in eluted fractions without Fc fragments, although having uncleaved IgG. The results showed that chromatography on transition metal ions chetated to CM-Asp-agarose is a promising approach to separation of Fab fragments from papain-digested human IgG solution. PMID:26974869

  8. Antimicrobial activity and the mechanism of silver nanoparticle thermosensitive gel

    PubMed Central

    Chen, Meiwan; Yang, Zhiwen; Wu, Hongmei; Pan, Xin; Xie, Xiaobao; Wu, Chuanbin

    2011-01-01

    Purpose The purpose of the present study was to elucidate the antimicrobial activity and mechanism of silver nanoparticles incorporated into thermosensitive gel (S-T-Gel) on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Patients and methods This study investigated the growth, permeability, and morphology of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa cells in order to observe the action of S-T-Gel on the membrane structure of these three bacteria. The cell morphology of normal and treated bacteria cells was assessed by transmission electron microscopy (TEM), and the effects of S-T-Gel on genome DNA of bacterial cells were evaluated by agarose gel electrophoresis. Results S-T-Gel showed promising activity against Staphylococcus aureus and moderate activity against Escherichia coli and Pseudomonas aeruginosa. The observation with TEM suggested that S-T-Gel may destroy the structure of bacterial cell membranes in order to enter the bacterial cell. S-T-Gel then condensed DNA and combined and coagulated with the cytoplasm of the damaged bacteria, resulting in the leakage of the cytoplasmic component and the eventual death of these three bacteria. In addition, the analysis of agarose gel electrophoresis demonstrated that S-T-Gel could increase the decomposability of genome DNA. Conclusion These results about promising antimicrobial activity and mechanism of S-T-Gel may be useful for further research and development in in-vivo studies. PMID:22131833

  9. Electrophoretic extraction of proteins from two-dimensional electrophoresis gel spots

    DOEpatents

    Zhang, Jian-Shi; Giometti, Carol S.; Tollaksen, Sandra L.

    1989-01-01

    After two-dimensional electrophoresis of proteins or the like, resulting in a polyacrylamide gel slab having a pattern of protein gel spots thereon, an individual protein gel spot is cored out from the slab, to form a gel spot core which is placed in an extraction tube, with a dialysis membrane across the lower end of the tube. Replicate gel spots can be cored out from replicate gel slabs and placed in the extraction tube. Molten agarose gel is poured into the extraction tube where the agarose gel hardens to form an immobilizing gel, covering the gel spot cores. The upper end portion of the extraction tube is filled with a volume of buffer solution, and the upper end is closed by another dialysis membrane. Upper and lower bodies of a buffer solution are brought into contact with the upper and lower membranes and are provided with electrodes connected to the positive and negative terminals of a DC power supply, thereby producing an electrical current which flows through the upper membrane, the volume of buffer solution, the agarose, the gel spot cores and the lower membrane. The current causes the proteins to be extracted electrophoretically from the gel spot cores, so that the extracted proteins accumulate and are contained in the space between the agarose gel and the upper membrane. A high percentage extraction of proteins is achieved. The extracted proteins can be removed and subjected to partial digestion by trypsin or the like, followed by two-dimensional electrophoresis, resulting in a gel slab having a pattern of peptide gel spots which can be cored out and subjected to electrophoretic extraction to extract individual peptides.

  10. THE MENTALLY RETARDED.

    ERIC Educational Resources Information Center

    JORDAN, THOMAS E.

    THIS BOOK PROVIDES A GUIDE TO THE BASIC CONCEPTS AND ISSUES IN THE FIELD OF MENTAL RETARDATION. THERE ARE MANY SOURCES OR CAUSES OF MENTAL RETARDATION AND THE FOLLOWING TYPES ARE EXPLAINED--(1) GENETIC OR CHEMICAL DISORDERS, (2) BIRTH TRAUMA, (3) SUBSEQUENT ACCIDENTS OR DISEASE, AND (4) ENVIRONMENTAL INFLUENCES. IT IS NOTED THAT MOST CASES INVOLVE…

  11. Mental Retardation in Perspective.

    ERIC Educational Resources Information Center

    Horvath, Michael; And Others

    This monograph presents a general introduction to the history, classification, and characteristics of mental retardation. It begins with a discussion of the history of mental retardation from ancient Greece and Rome to the present. The beginnings of special education are traced to the early 19th century in Europe. Major influences in treatment of…

  12. Vignettes in Mental Retardation.

    ERIC Educational Resources Information Center

    Crissey, Marie Skodak

    1983-01-01

    The use of the family history chart and the "Binet-Simon Scale" to study mental retardation in the early 20th century are considered, along with the implications of this practice. With the thesis that mental retardation was primarily familial and hereditary, limiting reproduction and segregation were viewed as appropriate approaches. (SEW)

  13. Brominated Flame Retardants

    EPA Science Inventory

    Brominated flame retardants (BFRs) belong to a large class of compounds known as organohalogens. BFRs are currently the largest marketed flame retardant group due to their high performance efficiency and low cost. In the commercial market, more than 75 different BFRs are recogniz...

  14. Consanguinity and mental retardation.

    PubMed

    Madhavan, T; Narayan, J

    1991-04-01

    Consanguinity among parents as a cause of mental retardation in their children is debatable. The present study was conducted to find out the effect of consanguinity on mental retardation where the causative factor is not established. A total of 517 mentally retarded persons and their families were studied out of which 160 were born of consanguineous marriage and 357 were of non-consanguineous marriage. The results indicated that, when there is a history of mental retardation in the family and if the parents are consanguineously married, the risk of mental retardation in the offspring is significantly high (chi 2 = 11.52; P less than 0.001). Among the consanguineously married families, the blood relationship of uncle-niece seems to have the highest risk of affecting the offsprings. The implications are discussed in detail. PMID:2072392

  15. Efficacy of transdermal magnesium ascorbyl phosphate delivery after ultrasound treatment with microbubbles in gel-type surrounding medium in mice.

    PubMed

    Liao, Ai-Ho; Lu, Ying-Jui; Hung, Chi-Ray; Yang, Meng-Yu

    2016-04-01

    Liquid microemulsions appropriate for topical application were obtained by increasing their viscosity through the addition of thickening agents. The present study first assessed the usefulness of ultrasound (US) plus US contrast agent, microbubbles (MBs), in agarose gel for enhancing transdermal drug delivery. The effect of US plus MBs in agarose gel on the penetration of the skin by magnesium ascorbyl phosphate (MAP) was explored both in vitro and in vivo. In the in vitro experiments, the stability of MBs was investigated by examining the penetration of MAP by the model drug, Evans blue, in two media: an agarose phantom and pig skin. The penetration depth in the agarose phantom and pig skin increased by 40% and 195%, respectively, when treated with US plus MBs in 0.1% agarose solution combined with MAP (UMB1), and by 48% and 206%, respectively, when treated with US plus MBs in 0.15% agarose solution and MAP (UMB2). The skin-whitening effects in C57BL/6J mice in the UMB1 and UMB2 groups over a 4-week experimental period were significantly increased by 63% and 70%, respectively, in the fourth week. The findings of this study suggest that the survival of MBs with US is affected by the viscosity of the surrounding medium, and that in mice, treatment with US plus MBs in a suitable agarose gel can increase skin permeability and enhance transdermal MAP delivery. PMID:26838887

  16. Fire-Retardant, Decorative Inks

    NASA Technical Reports Server (NTRS)

    Kourtides, D.; Nir, Z.; Mikroyannidis, J.

    1987-01-01

    Effectiveness of fire-retardant additives evaluated. Fire retardance of decorative acrylic printing inks for aircraft interiors enhanced by certain commercial and experimental fire-retardant additives, according to study.

  17. Identification of cisplatin-binding proteins using agarose conjugates of platinum compounds.

    PubMed

    Karasawa, Takatoshi; Sibrian-Vazquez, Martha; Strongin, Robert M; Steyger, Peter S

    2013-01-01

    Cisplatin is widely used as an antineoplastic drug, but its ototoxic and nephrotoxic side-effects, as well as the inherent or acquired resistance of some cancers to cisplatin, remain significant clinical problems. Cisplatin's selectivity in killing rapidly proliferating cancer cells is largely dependent on covalent binding to DNA via cisplatin's chloride sites that had been aquated. We hypothesized that cisplatin's toxicity in slowly proliferating or terminally differentiated cells is primarily due to drug-protein interactions, instead of drug-DNA binding. To identify proteins that bind to cisplatin, we synthesized two different platinum-agarose conjugates, one with two amino groups and another with two chlorides attached to platinum that are available for protein binding, and conducted pull-down assays using cochlear and kidney cells. Mass spectrometric analysis on protein bands after gel electrophoresis and Coomassie blue staining identified several proteins, including myosin IIA, glucose-regulated protein 94 (GRP94), heat shock protein 90 (HSP90), calreticulin, valosin containing protein (VCP), and ribosomal protein L5, as cisplatin-binding proteins. Future studies on the interaction of these proteins with cisplatin will elucidate whether these drug-protein interactions are involved in ototoxicity and nephrotoxicity, or contribute to tumor sensitivity or resistance to cisplatin treatment. PMID:23755301

  18. Identification of Cisplatin-Binding Proteins Using Agarose Conjugates of Platinum Compounds

    PubMed Central

    Karasawa, Takatoshi; Sibrian-Vazquez, Martha; Strongin, Robert M.; Steyger, Peter S.

    2013-01-01

    Cisplatin is widely used as an antineoplastic drug, but its ototoxic and nephrotoxic side-effects, as well as the inherent or acquired resistance of some cancers to cisplatin, remain significant clinical problems. Cisplatin's selectivity in killing rapidly proliferating cancer cells is largely dependent on covalent binding to DNA via cisplatin's chloride sites that had been aquated. We hypothesized that cisplatin's toxicity in slowly proliferating or terminally differentiated cells is primarily due to drug-protein interactions, instead of drug-DNA binding. To identify proteins that bind to cisplatin, we synthesized two different platinum-agarose conjugates, one with two amino groups and another with two chlorides attached to platinum that are available for protein binding, and conducted pull-down assays using cochlear and kidney cells. Mass spectrometric analysis on protein bands after gel electrophoresis and Coomassie blue staining identified several proteins, including myosin IIA, glucose-regulated protein 94 (GRP94), heat shock protein 90 (HSP90), calreticulin, valosin containing protein (VCP), and ribosomal protein L5, as cisplatin-binding proteins. Future studies on the interaction of these proteins with cisplatin will elucidate whether these drug-protein interactions are involved in ototoxicity and nephrotoxicity, or contribute to tumor sensitivity or resistance to cisplatin treatment. PMID:23755301

  19. Comparison of electrical conductivities of various brain phantom gels: Developing a ‘Brain Gel Model’

    PubMed Central

    Kandadai, Madhuvanthi A.; Raymond, Jason L.; Shaw, George J.

    2012-01-01

    The use of conducting gels to mimic brain and other tissues is of increasing interest in the development of new medical devices. Currently, there are few such models that can be utilized at physiologic temperatures. In this work, the conductivities of agar, agarose and gelatin gels were manipulated by varying NaCl concentration from 0–1 mg/ml. The AC conductivity was measured at room and physiological temperatures (37°C) in the 100–500 Hz frequency range. Conductivity (σ) was nearly independent of frequency but increased linearly with NaCl concentration and was higher at physiological temperatures in these gels. A formula for predicting conductivity as a function of NaCl concentration was derived for each gel type. The overall goal is to develop a ‘brain gel model’, for studying low frequency electrical properties of the brain and other tissues at physiological temperatures. PMID:23139442

  20. Comparison of electrical conductivities of various brain phantom gels: Developing a 'Brain Gel Model'

    PubMed

    Kandadai, Madhuvanthi A; Raymond, Jason L; Shaw, George J

    2012-12-01

    The use of conducting gels to mimic brain and other tissues is of increasing interest in the development of new medical devices. Currently, there are few such models that can be utilized at physiologic temperatures. In this work, the conductivities of agar, agarose and gelatin gels were manipulated by varying NaCl concentration from 0-1 mg/ml. The AC conductivity was measured at room and physiological temperatures (37°C) in the 100-500 Hz frequency range. Conductivity (σ) was nearly independent of frequency but increased linearly with NaCl concentration and was higher at physiological temperatures in these gels. A formula for predicting conductivity as a function of NaCl concentration was derived for each gel type. The overall goal is to develop a 'brain gel model', for studying low frequency electrical properties of the brain and other tissues at physiological temperatures. PMID:23139442

  1. Anion-switchable supramolecular gels for controlling pharmaceutical crystal growth

    NASA Astrophysics Data System (ADS)

    Foster, Jonathan A.; Piepenbrock, Marc-Oliver M.; Lloyd, Gareth O.; Clarke, Nigel; Howard, Judith A. K.; Steed, Jonathan W.

    2010-12-01

    We describe the use of low-molecular-weight supramolecular gels as media for the growth of molecular crystals. Growth of a range of crystals of organic compounds, including pharmaceuticals, was achieved in bis(urea) gels. Low-molecular-weight supramolecular gelators allow access to an unlimited range of solvent systems, in contrast to conventional aqueous gels such as gelatin and agarose. A detailed study of carbamazepine crystal growth in four different bis(urea) gelators, including a metallogelator, is reported. The crystallization of a range of other drug substances, namely sparfloxacin, piroxicam, theophylline, caffeine, ibuprofen, acetaminophen (paracetamol), sulindac and indomethacin, was also achieved in supramolecular gel media without co-crystal formation. In many cases, crystals can be conveniently recovered from the gels by using supramolecular anion-triggered gel dissolution; however, crystals of substances that themselves bind to anions are dissolved by them. Overall, supramolecular gel-phase crystallization offers an extremely versatile new tool in pharmaceutical polymorph screening.

  2. Preventing Mental Retardation

    PubMed Central

    Fotheringham, John B.

    1974-01-01

    Influences producing mental retardation can be divided into three categories: inherited factors, health problems and social-emotional influences. This article outlines steps which can be taken to reduce the first two categories, both pre and postnatally. PMID:20469133

  3. Fire retardant polyisocyanurate foam

    NASA Technical Reports Server (NTRS)

    Riccitiello, S. R.; Parker, J. A.

    1972-01-01

    Fire retardant properties of low density polymer foam are increased. Foam has pendant nitrile groups which form thermally-stable heterocyclic structures at temperature below degradation temperature of urethane linkages.

  4. Litter-Spinning Retarders

    NASA Technical Reports Server (NTRS)

    Wilson, John C.

    1995-01-01

    Aerodynamic plates stop litter from spinning during hoisting by helicopter. Features of proposed litter-spinning retarders include convenience of deployment and independence from ground restraint. Retarder plate(s) folded flat against bottom of litter during storage or while litter is loaded. Plate(s) held in storage position by latch that releases manually or automatically as litter is hoisted. Upon release, springs move plates into deployed position.

  5. Characterization of agarose as an encapsulation medium for particulate specimens for transmission electron microscopy.

    PubMed

    Wood, J I; Klomparens, K L

    1993-07-01

    Agarose, agar, and gelatin were initially compared as encapsulation media for 3 structurally diverse particulate specimens: bacteria, yeast, and mitochondria. Agarose proved superior to both gelatin and agar for ease of handling and overall image quality (minimum background). All sample types exhibited high quality fixation and structural detail with no heat damage from the agarose medium. Based on this finding, we further characterized agarose encapsulation as affected by post-fixation, en bloc staining and resin type. Osmium tetroxide post-fixation, followed by en bloc uranyl acetate staining, could be performed without an increase in the electron density of the encapsulation medium. Agarose proved successful as an encapsulation medium regardless of the resin type or preparation protocol, thus providing flexibility in experimental design and excellent results over a range of variables. PMID:8358076

  6. Using chondroitin sulfate to improve the viability and biosynthesis of chondrocytes encapsulated in interpenetrating network (IPN) hydrogels of agarose and poly(ethylene glycol) diacrylate.

    PubMed

    Ingavle, Ganesh C; Dormer, Nathan H; Gehrke, Stevin H; Detamore, Michael S

    2012-01-01

    We recently introduced agarose-poly(ethylene glycol) diacrylate (PEGDA) interpenetrating network (IPN) hydrogels to cartilage tissue engineering that were able to encapsulate viable cells and provide a significant improvement in mechanical performance relative to its two constituent hydrogels. The goal of the current study was to develop a novel synthesis protocol to incorporate methacrylated chondroitin sulfate (MCS) into the IPN design hypothesized to improve cell viability and biosynthesis. The IPN was formed by encapsulating porcine chondrocytes in agarose, soaking the construct in a solution of 1:10 MCS:PEGDA, which was then photopolymerized to form a copolymer network as the second network. The IPN with incorporated CS (CS-IPN) (~0.5 wt%) resulted in a 4- to 5-fold increase in the compressive elastic modulus relative to either the PEGDA or agarose gels. After 6 weeks of in vitro culture, more than 50% of the encapsulated chondrocytes remained viable within the CS-modified IPN, in contrast to 35% viability observed in the unmodified. At week 6, the CS-IPN had significantly higher normalized GAG contents (347 ± 34 μg/μg) than unmodified IPNs (158 ± 27 μg/μg, P < 0.05). Overall, the approach of incorporating biopolymers such as CS from native tissue may provide favorable micro-environment and beneficial signals to cells to enhance their overall performance in IPNs. PMID:22116661

  7. A simple gel electrophoresis method for separating polyhedral gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Kim, Suhee; Lee, Hye Jin

    2015-07-01

    In this paper, a simple approach to separate differently shaped and sized polyhedral gold nanoparticles (NPs) within colloidal solutions via gel electrophoresis is described. Gel running parameters for separating efficiently gold NPs including gel composition, added surfactant types and applied voltage were investigated. The plasmonic properties and physical structure of the separated NPs extracted from the gel matrix were then investigated using transmission electron microscopy (TEM) and UV-vis spectrophotometry respectively. Data analysis revealed that gel electrophoresis conditions of a 1.5 % agarose gel with 0.1 % sodium dodecyl sulfate (SDS) surfactant under an applied voltage of 100 V resulted in the selective isolation of ~ 50 nm polyhedral shaped gold nanoparticles. Further efforts are underway to apply the method to purify biomolecule-conjugated polyhedral Au NPs that can be readily used for NP-enhanced biosensing platforms.

  8. Amphiphilic agarose-based adsorbents for chromatography. Comparative study of adsorption capacities and desorption efficiencies.

    PubMed

    Oscarsson, S; Angulo-Tatis, D; Chaga, G; Porath, J

    1995-01-01

    A number of hydrophobic derivatives attached to cross-linked agarose were studied as protein adsorbents. Differences in the adsorption and desorption behaviour were determined as functions of type and concentration of selected salts. Whereas octyl- and phenyl-Sepharose adsorb serum albumin preferentially, pyridyl-S-agarose shows a much stronger preferential affinity for IgG in the presence of high concentrations of lyotropic salts, such as sulphates. In contrast to pyridyl-S-agarose, a large portion of proteins remained fixed to octyl- and phenyl-Sepharose after extensive washing with 1 M NaOH. PMID:7881534

  9. Encapsulation of adult human mesenchymal stem cells within collagen-agarose microenvironments.

    PubMed

    Batorsky, Anna; Liao, Jiehong; Lund, Amanda W; Plopper, George E; Stegemann, Jan P

    2005-11-20

    Reliable control over the process of cell differentiation is a major challenge in moving stem cell-based therapies forward. The composition of the extracellular matrix (ECM) is known to play an important role in modulating differentiation. We have developed a system to encapsulate adult human mesenchymal stem cells (hMSC) within spherical three-dimensional (3D) microenvironments consisting of a defined mixture of collagen Type I and agarose polymers. These protein-based beads were produced by emulsification of liquid hMSC-matrix suspensions in a silicone fluid phase and subsequent gelation to form hydrogel beads, which were collected by centrifugation and placed in culture. Bead size and size distribution could be varied by changing the encapsulation parameters (impeller speed and blade separation), and beads in the range of 30-150 microns in diameter were reliably produced. Collagen concentrations up to 40% (wt/wt) could be incorporated into the bead matrix. Visible light and fluorescence microscopy confirmed that the collagen matrix was uniformly distributed throughout the beads. Cell viability post-encapsulation was in the range of 75-90% for all bead formulations (similar to control slab gels) and remained at this level for 8 days in culture. Fluorescent staining of the actin cytoskeleton revealed that hMSC spreading increased with increasing collagen concentration. This system of producing 3D microenvironments of defined matrix composition therefore offers a way to control cell-matrix interactions and thereby guide hMSC differentiation. The bead format allows the use of small amounts of matrix proteins, and such beads can potentially be used as a cell delivery vehicle in tissue repair applications. PMID:16080186

  10. Non-monotonic mobility vs. length dependence observed in electrophoretic separation of 25 bp DNA ladder in Pluronic gels.

    NASA Astrophysics Data System (ADS)

    You, Seungyong; van Winkle, David

    2009-03-01

    We electrophoresed a double-stranded DNA ladder first in an agarose gel, then in gels of Pluronic F-127 at room temperature. The DNA ladder consisted of 19 discrete fragments ranging in length from 25 to 450 bp at 25 bp increments plus 500 bp. The DNA fragments were first separated in agarose gel and stacked normally with 25 bp having the highest mobility. A single lane of the separated DNA ladder in the agarose gel was inserted at the edge of a Pluronic gel slab. The DNA was electrophoresed from the agarose into the Pluronic gels perpendicular to the original separation axis. Mobilities of DNA fragments increased from 25 bp to 175 bp and then decreased from 175 bp to 500 bp. The 25 bp and 500 bp bands of the ladder had approximately the same mobility in several different Pluronic gel concentrations. Both were slower than most bands in between. The highest mobility fragments with length of 175 bp have 59.5 nm contour length which is about 3.5 times the diameter of a micelle (17 nm). This result suggests a crossover from chromatographic separation to electrophoretic separation for these short DNAs. This research is supported by the state of Florida (Martech) and Research Corporation.

  11. Vignettes in Mental Retardation.

    ERIC Educational Resources Information Center

    Crissey, Marie Skodak

    1983-01-01

    Described are turn-of-the-century (1900) efforts of E. Johnstone, Vineland Training School for the mentally retarded; H. Goddard, psychologist (also at Vineland); and C. Davenport, Carnegie Foundation biological laboratory, Coldspring Harbor; to identify the roles of genetic heredity and environmental impact, and thus to eradicate or ameliorate…

  12. Epidemiology of Mental Retardation.

    ERIC Educational Resources Information Center

    Heber, Rick

    Prevalence data on mental retardation is presented including international estimates on general prevalence, age directions, geographical variations within the United States, racial and ethnic variations, economic class distributions, family variations, and population distribution in institutions. Statistics are also provided in areas of specific…

  13. Monkey Retardate Learning Analysis

    ERIC Educational Resources Information Center

    Chamove, A. S.; Molinaro, T. J.

    1978-01-01

    Seven rhesus monkeys reared on diets high in phenylalanine to induce phenylketonuria (PKU--a metabolic disorder associated with mental retardation if untreated) were compared with normal, pair-fed, and younger controls; frontal brain-lesioned monkeys; and those raised on high-tryptophan diets in three object discrimination tasks. (Author)

  14. Flame retardant spandex type polyurethanes

    NASA Technical Reports Server (NTRS)

    Howarth, J. T.; Sheth, S.; Sidman, K. R.; Massucco, A. A. (Inventor)

    1978-01-01

    Flame retardant elastomeric compositions were developed, comprised of: (1) spandex type polyurethane having incorporated into the polymer chain, halogen containing polyols; (2) conventional spandex type polyurethanes in physical admixture flame retardant additives; and (3) fluoroelastomeric resins in physical admixture with flame retardant additives. Methods of preparing fibers of the flame retardant elastomeric materials are presented and articles of manufacture comprised of the elastomeric materials are mentioned.

  15. Ultra-deep desulfurization via reactive adsorption on peroxophosphomolybdate/agarose hybrids.

    PubMed

    Xu, Jian; Li, Huacheng; Wang, Shengtian; Luo, Fang; Liu, Yunyu; Wang, Xiaohong; Jiang, Zijiang

    2014-09-01

    A catalyst system composed of peroxophosphomolybdates as catalytic center and agarose as matrix material had been designed. The [C16H33N(CH3)3]3[PO4{MoO(O2)2}4]/agarose (C16PMo(O2)2/agarose) hybrid was found to be active for oxidation desulfurization (ODS) of dibenzothiophene (DBT) or real fuel into corresponding sulfone by H2O2 as an oxidant, while the sulfur content could be reduced to 5ppm. The higher activity comes from its components including [PO4{MoO(O2)2}4] catalytic sites, the hydrophobic quaternary ammonium cation affinity to low polarity substrates, and agarose matrix affinity to H2O2 and sulfone. During the oxidative reaction, the mass transfer resistance between H2O2 and organic sulfurs could be decreased and the reaction rate could increase by the assistance of agarose and hydrophobic tails of [C16H33N(CH3)3]3[PO4{MoO(O2)2}4]. Meanwhile, the oxidative products could be adsorbed by agarose matrix to give clean fuel avoiding the post-treatment. In addition, the hybrid was easily regenerated to be reused. PMID:24997975

  16. Effects of agarose mold compliance and surface roughness on self-assembled meniscus-shaped constructs

    PubMed Central

    Gunja, Najmuddin J.; Huey, Dan J.; James, Regis A.; Athanasiou, Kyriacos A.

    2009-01-01

    The meniscus is a fibrocartilaginous tissue that is critically important to the loading patterns within the knee joint. If the meniscus structure is compromised, there is little chance of healing due to limited vascularity in the inner portions of the tissue. Several tissue engineering techniques to mimic the complex geometry of the meniscus have been employed. Of these, a self-assembly, scaffoldless approach employing agarose molds avoids drawbacks associated with scaffold use while still allowing formation of robust tissue. In this experiment two factors were examined, agarose percentage and mold surface roughness, in an effort to consistently obtain constructs with adequate geometric properties. Co-cultures of ACs and MCs (50:50 ratio) were cultured in smooth or rough molds composed of 1% or 2% agarose for 4 wks. Morphological results showed that constructs formed in 1% agarose molds, particularly smooth molds, were able to maintain their shape over the 4 wk culture period. Significant increases were observed for the collagen II to collagen I ratio, total collagen, GAG, and tensile and compressive properties in smooth wells. Cell number per construct was higher in the rough wells. Overall, it was observed that the topology of an agarose surface may be able to affect the phenotypic properties of cells that are on that surface, with smooth surfaces supporting a more chondrocytic phenotype. In addition, wells made from 1% agarose were able to prevent construct buckling potentially due to their higher compliance. PMID:19658151

  17. Mental Retardation, Selected Conference Papers.

    ERIC Educational Resources Information Center

    Scheerenberger, R.C., Ed.

    A compilation of selected papers includes the following: comprehensive diagnostic services; pediatric aspects of diagnosis; psychological evaluation of the severely retarded; use of social competency devices; diagnosis of the adult retarded; programing for the severely retarded; nursery school experiences for the trainable; a practical approach to…

  18. Teaching the Educable Mentally Retarded.

    ERIC Educational Resources Information Center

    Love, Harold D.

    The text discusses the behavior, evaluation, and education of mentally retarded children. Harold D. Love presents an overview of the retarded, a description of intelligence and personality tests, and a historical survey of retardation; Virginia Cantrell reviews the educational philosophies and methods of Itard, Seguin, and Montessori. Shirley K.…

  19. Optimal processing for gel electrophoresis images: Applying Monte Carlo Tree Search in GelApp.

    PubMed

    Nguyen, Phi-Vu; Ghezal, Ali; Hsueh, Ya-Chih; Boudier, Thomas; Gan, Samuel Ken-En; Lee, Hwee Kuan

    2016-08-01

    In biomedical research, gel band size estimation in electrophoresis analysis is a routine process. To facilitate and automate this process, numerous software have been released, notably the GelApp mobile app. However, the band detection accuracy is limited due to a band detection algorithm that cannot adapt to the variations in input images. To address this, we used the Monte Carlo Tree Search with Upper Confidence Bound (MCTS-UCB) method to efficiently search for optimal image processing pipelines for the band detection task, thereby improving the segmentation algorithm. Incorporating this into GelApp, we report a significant enhancement of gel band detection accuracy by 55.9 ± 2.0% for protein polyacrylamide gels, and 35.9 ± 2.5% for DNA SYBR green agarose gels. This implementation is a proof-of-concept in demonstrating MCTS-UCB as a strategy to optimize general image segmentation. The improved version of GelApp-GelApp 2.0-is freely available on both Google Play Store (for Android platform), and Apple App Store (for iOS platform). PMID:27251892

  20. 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.

  1. 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

  2. Fire and smoke retardants

    NASA Astrophysics Data System (ADS)

    Drews, M. J.

    Despite a reduction in Federal regulatory activity, research concerned with flame retardancy and smoke suppression in the private sector appears to be increasing. This trend seem related to the increased utilization of plastics for end uses which traditionally have employed metal or wood products. As a result, new markets have appeared for thermally stable and fire resistance thermoplastic materials, and this in turn has spurred research and development activity. In addition, public awareness of the dangers associated with fire has increased as a result of several highly publicized hotel and restaurant fires within the past two years. The consumers recognition of flammability characteristics as important materials property considerations has increased. The current status of fire and smoke retardant chemistry and research are summarized.

  3. Flame Retardant Epoxy Resins

    NASA Technical Reports Server (NTRS)

    Thompson, C. M.; Smith, J. G., Jr.; Connell, J. W.; Hergenrother, P. M.; Lyon, R. E.

    2004-01-01

    As part of a program to develop fire resistant exterior composite structures for future subsonic commercial aircraft, flame retardant epoxy resins are under investigation. Epoxies and their curing agents (aromatic diamines) containing phosphorus were synthesized and used to prepare epoxy formulations. Phosphorus was incorporated within the backbone of the epoxy resin and not used as an additive. The resulting cured epoxies were characterized by thermogravimetric analysis, propane torch test, elemental analysis and microscale combustion calorimetry. Several formulations showed excellent flame retardation with phosphorous contents as low as 1.5% by weight. The fracture toughness of plaques of several cured formulations was determined on single-edge notched bend specimens. The chemistry and properties of these new epoxy formulations are discussed.

  4. Modeling the Dynamics of Gel Electrophorresis in the High School Classroom

    ERIC Educational Resources Information Center

    Saucedo, Skyler R.

    2013-01-01

    Gel electrophoresis, used by geneticists and forensic experts alike, is an immensely popular technique that utilizes an electric field to separate molecules and proteins by size and charge. At the microscopic level, a dye or complex protein like DNA is passed through agarose, a gelatinous three-dimensional matrix of pores and nano-sized tunnels.…

  5. Educable Mentally Retarded, Level I.

    ERIC Educational Resources Information Center

    Suo, Minnie Alice; Willemin, Helen

    Intended for teachers of special classes of educable mentally retarded children aged 6 to 8 (mental age = 3.5 to 4.9), the guide stresses skills necessary to the development of physical, personal and social, and vocational competency. An introduction defines philosophy and goals, outlines the educable mentally retarded program and the readiness…

  6. China's Approach to Mental Retardation.

    ERIC Educational Resources Information Center

    Hittman, Stephan

    History, tradition, culture, and superstition have played significant roles in influencing Chinese attitudes toward the mentally retarded. China's overwhelmingly rural, agricultural society has made it dependent upon a huge force of semi-skilled and unskilled labor, to which the retarded are capable of contribution. The stress on self-reliance,…

  7. The Mentally Retarded in Sweden.

    ERIC Educational Resources Information Center

    Grunewald, Karl

    Described are residential and educational services provided for mentally retarded (MC) children and adults in Sweden. Normalization is the focus of the services which make maximum use of mental and physical capacities to reduce the handicap of mental retardation. Described are general principles, and four stages involving development of services…

  8. Flame retarded asphalt blend composition

    SciTech Connect

    Walters, R.B.

    1987-04-21

    This patent describes a flame retarded asphalt composition consisting essentially of a blend of: (a) thermoplastic elastomer modified bitumen; (b) 20-30 wt % inert filler; (c) 1-20 wt % of at least one halogenated flame retardant; and (d) 1-5 wt % of at least one inorganic phosphorus containing compound selected from the group consisting of ammonium phosphate compounds and red phosphorus.

  9. THE PATHOLOGY OF MENTAL RETARDATION.

    ERIC Educational Resources Information Center

    CROME, L.; STERN, J.

    DATA FROM RECENT COMPREHENSIVE STUDIES OF THE PATHOLOGY OF MENTAL RETARDATION ARE ASSEMBLED, INCLUDING MATERIAL ON ETIOLOGY, MORPHOLOGY, BIOCHEMISTRY, AND LABORATORY DIAGNOSIS. AREAS COVERED ARE (1) GENETIC CAUSES OF MENTAL RETARDATION, (2) DISORDERS OF GESTATION, (3) BIRTH INJURY, (4) GENERAL CONSIDERATIONS OF POSTNATAL CAUSES OF MENTAL…

  10. Fabricating neuromast-inspired gel structures for membrane-based hair cell sensing

    NASA Astrophysics Data System (ADS)

    Tamaddoni, Nima J.; Stephens, Christopher P.; Sarles, S. A.

    2012-04-01

    Recent research has shown that a new class of mechanical sensor, assembled from biomolecules and which features an artificial cell membrane as the sensing element, can be used to mimic basic hair cell mechanotransduction in vertebrates. The work presented in this paper is motivated by the need to increase sensor performance and stability by refining the methods used to fabricate and connect lipid-encapsulated hydrogels. Inspired by superficial neuromasts found on fish, three hydrogel materials are compared for their ability to be readily shaped into neuromast-inspired geometries and enable lipid bilayer formation using self-assembly at an oil/water interface. Agarose, polyethylene glycol (PEG, 6kg/mole), and hydroxyethyl methacrylate (HEMA) gel materials are compared. The results of this initial study determined that UV-curable gel materials such as PEG and HEMA enable more accurate shaping of the gel-needed for developing a sensor that uses a gel material both for mechanical support and membrane formation-compared to agarose. However, the lower hydrophobicity of agarose and PEG materials provide a more fluid, water-like environment for membrane formation-unlike HEMA. In working toward a neuromast-inspired design, a final experiment demonstrates that a bilayer can also be formed directly between two lipid-covered PEG surfaces. These initial results suggest that candidate gel materials with a low hydrophobicity, high fluidity, and a low modulus can be used to provide membrane support.

  11. Effects of calcium salts of acidic monomers on mineral induction of phosphoprotein immobilized to agarose beads.

    PubMed

    Ito, Shuichi; Iijima, Masahiro; Motai, Fumiko; Mizoguchi, Itaru; Saito, Takashi

    2012-10-01

    The aim of this study is to evaluate the mineralizing potential of acidic monomers and their calcium salts for mineralization, using an in vitro mineral induction model. Phosvitin (PV) was used as a model phosphoprotein in this study. PV was immobilized on agarose beads with divinyl sulfone. Five aliquots of agarose-immobilized PV, acidic monomers, and their calcium salts were incubated in mineralizing solution at various concentrations. The PV beads and acidic monomers were incubated at 37°C. Samples were taken at several time points during the incubation. Then, the agarose beads were analyzed for bound calcium by atomic absorption spectrometry. The mineral formed on the agarose beads was identified as an apatite by microarea X-ray diffraction. Additionally, the specimens were observed using scanning electron microscopy (SEM). Mineral induction time decreased with increasing solution saturation. 4-METCa salt [calcium salt of 4-methacryloxyethyl trimellitate (CMET)] significantly reduced the mineral induction time. Using these data, the interfacial tension for mineral induction of PV and CMET was determined to be 90.1 and 92.7 ergs/cm(2), respectively. The mineral induced in each specimen after incubation for 24 h was identified by its X-ray diffraction pattern as apatite. SEM observation showed that lath-shaped crystals were formed on the surfaces of the CMET. We conclude that CMET could play a role in dentin remineralization. PMID:22623052

  12. Agarose-Based Substrate Modification Technique for Chemical and Physical Guiding of Neurons In Vitro.

    PubMed

    Krumpholz, Katharina; Rogal, Julia; El Hasni, Akram; Schnakenberg, Uwe; Bräunig, Peter; Bui-Göbbels, Katrin

    2015-08-26

    A new low cost and highly reproducible technique is presented that provides patterned cell culture substrates. These allow for selective positioning of cells and a chemically and mechanically directed guiding of their extensions. The patterned substrates consist of structured agarose hydrogels molded from reusable silicon micro templates. These templates consist of pins arranged equidistantly in squares, connected by bars, which mold corresponding wells and channels in the nonadhesive agarose hydrogel. Subsequent slice production with a standard vibratome, comprising the described template pattern, completes substrate production. Invertebrate neurons of locusts and pond snails are used for this application as they offer the advantage over vertebrate cells as being very large and suitable for cultivation in low cell density. Their neurons adhere to and grow only on the adhesive areas not covered by the agarose. Agarose slices of 50 μm thickness placed on glass, polystyrene, or MEA surfaces position and immobilize the neurons in the wells, and the channels guide their neurite outgrowth toward neighboring wells. In addition to the application with invertebrate neurons, the technique may also provide the potential for the application of a wide range of cell types. Long-term objective is the achievement of isolated low-density neuronal networks on MEAs or different culture substrates for various network analysis applications. PMID:26237337

  13. Gel electrophoretic restriction fragment length polymorphism analysis of DNA derived from individual nematodes, using the PhastSystem.

    PubMed

    Triga, D; Pamjav, H; Vellai, T; Fodor, A; Buzás, Z

    1999-06-01

    The DNA sequences constituting the internal transcribed spacer region, located between 18S and 26S rDNA genes within the rRNA operon, derived from single nematodes of two genera (Steinernema and Heterorhabditis) were amplified by polymerase chain reaction (PCR) and subjected to digestion by four restriction enzymes. The digests were analyzed by restriction fragment length polymorphism (RFLP) gel electrophoresis on the PhastSystem, using 7.5%T, 5%C(Bis) polyacrylamide. The downscaling from conventional agarose to PhastSystem gels permitted the analysis to be done on individual nematodes, rather than on mixed samples with average properties. The analysis time was reduced so as to allow for the electrophoretic separation on 200 samples/workday. The resulting patterns of DNA fragments differed from those obtained by agarose gel electrophoresis under conventional conditions by an increased number of detected fragments. The PhastSystem gel analysis provides the basis for taxonomical revisions. PMID:10380768

  14. 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.

  15. Agarose Gel Electrophoresis System in the Classroom: Detection of DNA Strand Breaks through the Alteration of Plasmid Topology

    ERIC Educational Resources Information Center

    De Mattos, J. C. P.; Dantas, F. J. S.; Caldeira-de-Araujo, A.; Moraes, M. O.

    2004-01-01

    Good quality scientific teaching depends on the ability of researchers to translate laboratory experiments into high school and undergraduate classes, bridging the advanced and basic science with common knowledge. A fast-growing field in biomedical sciences is oxidative stress, which has been associated to several diseases, including cancer and…

  16. Neurotoxicity of brominated flame retardants

    EPA Science Inventory

    Polybrominated diphenyl ethers (PBDEs) have been commonly used as commercial flame retardants in a variety of products including plastics and textiles. Despite their decreasing usage worldwide, congeners continue to accumulate in the environment, including soil, dust, food, anima...

  17. Can earthworms survive fire retardants?

    USGS Publications Warehouse

    Beyer, W.N.; Olson, A.

    1996-01-01

    Most common fire retardants are foams or are similar to common agricultural fertilizers, such as ammonium sulfate and ammonium phosphate. Although fire retardants are widely applied to soils, we lack basic information about their toxicities to soil organisms. We measured the toxicity of five fire retardants (Firetrol LCG-R, Firetrol GTS-R, Silv-Ex Foam Concentrate, Phos-chek D-75, and Phos-chek WD-881) to earthworms using the pesticide toxicity test developed for earthworms by the European Economic Community. None was lethal at 1,000 ppm in the soil, which was suggested as a relatively high exposure under normal applications. We concluded that the fire retardants tested are relatively nontoxic to soil organisms compared with other environmental chemicals and that they probably do not reduce earthworm populations when applied under usual firefighting conditions.

  18. INTRODUCTION TO BROMINATED FLAME RETARDANTS

    EPA Science Inventory

    Brominated flame retardants (BFRs) are a large and diverse class of major industrial products used to provide fire safety. Tetrabromobisphenol A (TBBPA), Hexabromocylocodecane (HBCD), and Polybrominated Diphenyl Ethers (PBDEs) are the major commercial compounds. TBBPA is a react...

  19. Intumescent Coatings as Fire Retardants

    NASA Technical Reports Server (NTRS)

    Fish, R. H.; Fohlen, G. M.; Parker, J. A.; Sawko, P. M.

    1970-01-01

    Fire-retardant paint, when activated by the heat of fire, reacts to form a thick, low-density, polymeric coating or char layer. Water vapor and sulphur dioxide are released during the intumescent reaction.

  20. Mullins effect behaviour under compression in micelle-templated silica and micelle-templated silica/agarose systems.

    PubMed

    Puértolas, J A; Vadillo, J L; Sánchez-Salcedo, S; Nieto, A; Gómez-Barrena, E; Vallet-Regí, M

    2012-02-01

    The mechanical properties of bioceramic conformed pieces based on micelle-templated silica (MTS) such as SBA15, MCM41 and MCM48 as well as MTS/agarose systems have been evaluated under static and cyclic compressive tests. The MTS pieces exhibited a brittle behaviour. Agarose, a biocompatible and biodegradable hydrogel, has been used to shape ceramic-agarose pieces following a low temperature shaping method. Agarose conferred toughness, ductility and a rubbery consistency up to a 60% strain in ceramic MTS/agarose systems leading to a maximum strength of 10-50 MPa, without losing their initial cylindrical structure. This combination of ceramic and organic matrix contributes to avoiding the inherent brittleness of the bioceramic and enhances the compression resistance of hydrogel. The presence of mechanical hysteresis, permanent deformation after the first cycle and recovery of the master monotonous curve of MTS/agarose systems indicate a Mullins-like effect similar to that found in carbon-filled rubber systems. We report this type of mechanical behaviour, the Mullins effect, for the first time in MTS bioceramics and MTS bioceramic/agarose systems. PMID:22076528

  1. Agarose functionalization: Synthesis of PEG-agarose amino acid nano-conjugate - its structural ramifications and interactions with BSA in a varying pH regime.

    PubMed

    Chudasama, Nishith A; Prasad, Kamalesh; Siddhanta, Arup Kumar

    2016-10-20

    In a rapid one-step method protein-mimicking large agarose amino acid framework (AAE; GPC 156.7kDa) was conjugated with polyethylene glycol (PEG 9kDa) affording nano-sized PEGylated amphoteric agarose (PEG-AAE; <10nm; DLS) containing amino, carboxyl and ester groups [overall degree of substitution (DS) 0.91]. The PEG groups were at the residual free carboxylic acid groups of succinate half-ester moiety at C-6 positions of the 1, 3 β-d-galactopyranose moieties of AAE. This new nano-sized PEG-AAE performed like a giant protein conjugate (GPC 331.2kDa) and exhibited pH-responsive interconversion between the triple helix and single-stranded random structures (optical rotatory dispersion) presenting a mixed solubility pattern like random coil (soluble), helical (soluble) and aggregate (precipitation) formations. Circular dichroism studies showed its pH-dependent complexation and decomplexation with bovine serum albumin (BSA). Such pH-responsive PEG-conjugate may be of pronounced therapeutic potential in the area of pharmacology as well as in sensing applications. PMID:27474620

  2. Understanding and Teaching the Dependent Retarded Child.

    ERIC Educational Resources Information Center

    Rosenzweig, Louis E.; Long, Julia

    Levels of mental retardation and school admission procedures for the dependent retarded (IQ's 30 to 50) are reviewed. Goals for all retarded and the application of goals to the dependent retarded are considered. Plans and procedures for both teacher and child activities along with suggestions for audiovisual and other materials are provided in the…

  3. The Mentally Retarded Offender: Annotated Bibliography.

    ERIC Educational Resources Information Center

    Schilit, Jeffrey; And Others

    An annotated bibliography of approximately 150 books and articles on the mentally retarded offender as well as 30 nonannotated entries are provided. Topics covered include such areas as characteristics of mentally retarded delinquents, rehabilitation of the retarded offender, community services for retarded persons, rights of the mentally…

  4. Passivated gel electrophoresis of charged nanospheres by light-scattering video tracking.

    PubMed

    Zhu, Xiaoming; Mason, Thomas G

    2014-08-15

    Gel electrophoresis (gel-EP) has been used for decades to separate charged biopolymers, such as DNA, RNA, and proteins, yet propagation of other charged colloidal objects, such as nanoparticles, during gel-EP has been studied comparatively little. Simply introducing anionic nanoparticles, such as sulfate-stabilized polystyrene nanospheres, in standard large-pore agarose gels commonly used for biomolecules does not automatically ensure propagation or size-separation because attractive interactions can exist between the gel and the nanoparticles. Whereas altering the surfaces of the nanoparticles is a possible solution, here, by contrast, we show that treating a common type I-A low-electroendoosmosis agarose gel with a passivation agent, such as poly-(ethyleneglycol), enables charged nanoparticles to propagate through large-pore passivated gels in a highly reproducible manner. Moreover, by taking advantage of the significant optical scattering from the nanoparticles, which is not easily measurable for biopolymers, relative to scattering from the gel, we perform real-time, light-scattering, video-tracking gel-EP. Continuous optical measurements of the propagation of bands of uniformly sized nanospheres in passivated gels provides the propagation distance, L, and velocity, v, as a function of time for different sphere radii, electric field strengths, gel concentrations, and passivation agent concentrations. The steady-state particle velocities vary linearly with applied electric field strength, E, for small E, but these velocities become non-linear for larger E, suggesting that strongly driven nanoparticles can become elastically trapped in the smaller pores of the gel, which act like blind holes, in a manner that thermal fluctuations cannot overcome. Based on this assumption, we introduce a simple model that fits the measured v(E) in both linear and non-linear regimes over a relevant range of applied voltages. PMID:24910054

  5. Cost-effective gel documentation using a web-cam.

    PubMed

    Goldmann, T; Zyzik, A; Loeschke, S; Lindsay, W; Vollmer, E

    2001-12-01

    In search for a cost effective gel documentation system applicable for different fields of molecular biology, we analyzed the capabilities of a cheap CCD-camera originally designed to capture images for transmission through the internet (web-cam) with regard to gel documentation. The camera was connected to a personal computer by universal serial bus (USB) and used for the documentation of DNA separated on agarose gels and stained by ethidium-bromide using the software provided with the camera. The web-cam provided digital images of sufficient quality for routine documentation and combined the low set-up costs of a Polaroid system with the low running costs of video capture systems, hence is ideal as a start-up system and as augmentation to existing equipment. PMID:11714515

  6. Direct electrochemistry of cytochrome c entrapped in agarose hydrogel in room temperature ionic liquids.

    PubMed

    Wang, Sui; Guo, Zhiyong; Zhang, Huina

    2011-08-01

    Direct electrochemistry of cytochrome c (cyt-c) entrapped in agarose hydrogel on gold electrode (Au), edge plane pyrolytic graphite electrode (EPPGE) and glassy carbon electrode (GC) in two room temperature ionic liquids was investigated. The effects of the addition of N,N-dimethylformamide (DMF) in the agarose-cyt-c film, water concentration in ionic liquids and exterior metal ions on the electrochemical behavior of cyt-c were monitored, and electrocatalytic properties of cyt-c were also done. Results showed that a good quasi-reversible redox behavior of cyt-c could be found after adding DMF in agarose-cyt-c film, and peak shape would not change after continuously scanning for 50 cycles. In addition, a certain amount of water in hydrophilic ionic liquids is necessary to maintain electrochemical activities of cyt-c, electrochemical performance of cyt-c is the best when the water content is 5.2% and 5.8% for 1-butyl-3-methylimidazolium bromide ([Bmim][Br]) and 1-butyl-3-methylimidazolium tetrafluoroborate([Bmim][BF(4)]) respectively. However, electrochemical activities of cyt-c are inhibited by exterior metal ions. Interestingly, cyt-c entrapped in agarose hydrogel on EPPGE and GC could catalyze the electroreduction of trichloroacetic acid (TCA) and tert-butyl hydroperoxide (t-BuOOH) in [Bmim][BF(4)], but could not in [Bmim][Br]. Reasons for above-mentioned differences of electrochemical properties of cyt-c in different ionic liquids were preliminarily discussed. PMID:21659008

  7. Iron detoxification by haemoperfusion through deferoxamine-conjugated agarose-polyacrolein microsphere beads.

    PubMed

    Horowitz, D; Margel, S; Shimoni, T

    1985-01-01

    The natural iron chelator deferoxamine was bonded to agarose-polyacrolein microsphere beads (APAMB). This novel deferoxamine-conjugated APAMB (DCA), when used as the sorbent in a plasma/haemoperfusion system, showed specific and rapid removal of iron from plasma and blood in vitro; in vivo experiments also showed specific iron removal. The advantages of this sorbent are minimal damage to biocompounds during haemoperfusion, high capacity and specificity to iron, and the possibility of reuse. PMID:3971021

  8. Retention of gene expression in porcine islets after agarose encapsulation and long-term culture.

    PubMed

    Dumpala, Pradeep R; Holdcraft, Robert W; Martis, Prithy C; Laramore, Melissa A; Parker, Thomas S; Levine, Daniel M; Smith, Barry H; Gazda, Lawrence S

    2016-08-01

    Agarose encapsulation of porcine islets allows extended in vitro culture, providing ample time to determine the functional capacity of the islets and conduct comprehensive microbiological safety testing prior to implantation as a treatment for type 1 diabetes mellitus. However, the effect that agarose encapsulation and long-term culture may have on porcine islet gene expression is unknown. The aim of the present study was to compare the transcriptome of encapsulated porcine islets following long-term in vitro culture against free islets cultured overnight. Global gene expression analysis revealed no significant change in the expression of 98.47% of genes. This indicates that the gene expression profile of free islets is highly conserved following encapsulation and long-term culture. Importantly, the expression levels of genes that code for critical hormones secreted by islets (insulin, glucagon, and somatostatin) as well as transcripts encoding proteins involved in their packaging and secretion are unchanged. While a small number of genes known to play roles in the insulin secretion and insulin signaling pathways are differentially expressed, our results show that overall gene expression is retained following islet isolation, agarose encapsulation, and long-term culture. PMID:27261433

  9. Tailor-made agarose-based reactive beads for hemoperfusion and plasma perfusion.

    PubMed

    Sideman, S; Lotan, N; Tabak, A; Manor, D; Mor, L; Taitelman, U; Brook, J; Tzipiniuk, A

    1984-01-01

    Composite beads of approximately 1 mm diameter, made of crosslinked agarose and containing Fuller's Earth or zirconium oxide powders, were prepared and used in extracorporeal systems for blood detoxification. The former was used for the removal of Paraquat, while the latter was used to remove inorganic phosphate from hyperphosphatemic animals with or without acute renal failure. The high surface area of the powder, combined with the low resistance to diffusion in the crosslinked agarose matrix, are highly advantageous. The crosslinking provides high mechanical strength, heat stability, prolonged shelf life, good blood flow characteristics, and prevents the release of fine particles into the blood. Crosslinked agarose beads of 1 mm diameter, containing chemically-bound heparin were also prepared, and used as a model for direct contact removal of LDL-cholesterol from the blood of familial hypercholesterolemic patients by hemoperfusion. The high capacity of these beads (over 5 mg LDL/mL beads) indicates that this clinical modality can replace the highly expensive plasmapheresis procedure presently used. PMID:6524925

  10. Homogeneous tosylation of agarose as an approach toward novel functional polysaccharide materials.

    PubMed

    Gericke, Martin; Heinze, Thomas

    2015-01-01

    The homogeneous tosylation of agarose was studied with respect to the effects of reaction parameters, such as reaction medium, time, and molar ratio, on the reaction course, the degree of substitution (DS) with tosyl/chloro deoxy groups, and the molecular structure. Tosyl agaroses (TOSA) with DS tosyl ≤ 1 .81 could be obtained in completely homogeneous reactions by using N,N-dimethylacetamide (DMA)/LiCl or 1,3-dimethyl-2-imidazolidinone (DMI) as solvents. The products were characterized by FT-IR and NMR spectroscopy and it was demonstrated that two types of substitution pattern can be achieved: (i) non-preferential substitution at position 6 of the 1 → 3-linked β-d-galactose unit (G-6) and position 2 of the 1 → 4-linked 3,6-anyhdro-α-L-galactose unit (LA-2) and (ii) regioselective tosylation at G-6, depending on whether the reaction is performed with or without LiCl. Finally, the nucleophilic displacement reaction of TOSA was studied using azide and ethylenediamine as representative nucleophiles. Novel deoxy-agarose derivatives were obtained that showed an interesting solubility behavior and will be used for creating functional polysaccharide materials. PMID:25965480

  11. Aqueous phase catalytic conversion of agarose to 5-hydroxymethylfurfural by metal chlorides

    SciTech Connect

    Yan, Lishi; Laskar, Dhrubojyoti D.; Lee, Suh-Jane; Yang, Bin

    2013-12-14

    Abstract: 5-HMF is a key intermediate for producing chemicals and fuels that can substitute for today’s petroleum-derived feedstocks. A series of metal chlorides, including NaCl, CaCl2, MgCl2, ZnCl2, CuCl2, FeCl3, and CrCl3, were comparatively investigated to catalyze agarose degradation for production of 5-HMF at temperature 180 oC, 200 oC, and 220 oC for 30 min, with catalyst concentration of 0.5% (w/w), 1% (w/w) and 5% (w/w), and substrate concentration of 2% (w/w). Our results revealed that alkali metal chlorides and alkali earth metal chlorides such as NaCl, CaCl2 and MgCl2 gave better 5-HMF yield compared with transition metal chlorides including ZnCl2, CrCl3, CuCl2 and FeCl3. 1% (w/w) MgCl2 was the more favorable catalyst for 5-HMF production from agarose, and resulted in 40.7% 5-HMF yield but no levulinic acid or lactic acid at 200 oC, 35 min. The reaction pathways of agarose degradation catalyzed by MgCl2 were also discussed.

  12. Immobilization of proteins on agarose beads, monitored in real time by bead injection spectroscopy

    PubMed Central

    Ruzicka*, Jaromir; Carroll, Andrea D.; Lähdesmäki, Ilkka

    2006-01-01

    Summary This work introduces a novel tool for the examination and optimization of protein immobilization protocols, by measuring the rate and yield of coupling reactions, as they take place on the surface of agarose beads in a well-stirred microreactor. The power of the Bead Injection Spectroscopy (BIS) technique is demonstrated on examples of amino coupling reactions for albumin, ovalbumin, lysozyme, human IgG, ribonuclease A and cytochrome C, using commercially available Aminolink® agarose beads. It was found, surprisingly, that currently recommended protocols for reductive amination can be shortened from several hours to several minutes, and that, contrary to literature data, the yield of coupling is dependent on pH and the isoelectric point of the protein. In addition, leakage of immobilized ligands can be measured by direct spectroscopic interrogation of captured beads in situ. The methodology presented in this work documents that BIS is a useful tool for quality control of agarose-based chromatographic supports, as well as for the optimization of a wide variety of immobilization chemistries, as used for synthesis of chromatographic supports, immobilization of enzymes, and derivatization of biosensing surfaces. PMID:16802025

  13. Development of novel fire retardants

    NASA Astrophysics Data System (ADS)

    Sigdel Regmi, Bhawani

    Numerous candidate environmentally-friendly, water-soluble, and non-toxic fire retardants and fire-retarding processes were developed and tested according to the ASTM D 3801 flammability test and the NRL 8093 smoldering test. Flame retardants that passed the ASTM D 3801 flammability test with the highest V0 rating were boron esters of guanidinium hydroxycarboxylate (glycolate, salicylate and dihydroxybenzoate), zinc gluconate borate ester, and cyanoacetate salts of organic bases (melaminium, cyanoguanidinium, and ammonium). Several related compounds pass this test with the lower V1 rating. Two new synergistic flame and smolder retarding systems were developed in which the individual components were incapable of preventing flame spread or smoldering but in combination they were highly effective. These systems were mixtures of either guanyl urea phosphate and boric acid or beta-alanine and boric acid. Compositions leading to the maximum solubility of boron oxides in the ammonium borate/sodium borate system were determined at several temperatures and the formation of mixtures exceeding 50% dissolved boric acid equivalents was found possible. These mixtures were applied as flame retardants for wood, paper, and carbon-loaded polyurethane foam both directly and indirectly by in situ precipitation of boric acid or zinc borate by appropriate chemical treatments. These all passed the ASTM flammability test with V0 rating. The performance of the boron-containing fire retardants is likely due to deposition of protective boron oxide coatings at elevated temperatures except where phosphate was present and a protective boron phosphate was deposited instead. In all cases, the oxidation of carbonaceous char was strongly inhibited. The hydroxycarboxylate groups generally formed intumescent chars during thermal decomposition that also contributed to fire retardancy.

  14. Auto cannibalism in mental retardation.

    PubMed

    Verma, Rohit; Mina, Shaily; Sachdeva, Ankur

    2014-01-01

    Mental retardation (MR) deems an individual more vulnerable to psychopathologies. The individual may develop an array of behavioral disturbances manifesting themselves in the form of aggressive and destructive conduct, violent fits of anger, stereotyped, or self-injuring behavior. Self-injurious behavior is heterogeneous in nature ranging from mild to severe variant. We report a case of a 7-year-old boy with MR with self-inflicted severe oral injuries of cannibalistic nature presenting as cleft lip and palate. A more extensive research is needed on the problem behaviors in mentally retarded patients for early detection and effective and timely intervention leading to a better outcome. PMID:24891909

  15. Short protocol for pulsed field gel electrophoresis of a variety of Clostridia species.

    PubMed

    Sperner, B; Schalch, B; Eisgruber, H; Stolle, A

    1999-07-01

    While pulsed field gel electrophoresis has become an important tool for genotyping of bacteria, one of its drawbacks is that standard methods are rather time-consuming. In order to overcome this problem, shortened procedures for DNA preparation have been developed for some bacterial species. The aim of this study was to examine if a short procedure used for pulsed field gel electrophoresis of Clostridium botulinum could be applied to other Clostridia species. For this, the protocol was modified and used to prepare the DNA of 34 strains of 25 different Clostridia species. In contrast to a standard procedure, which takes at least 5 days from DNA extraction to completion of the electrophoresis, this protocol yielded results within 2 days. In order to directly compare the results of the short protocol with those of the standard, long procedure, parallel DNA preparations were performed using both methods and the two DNA samples thus obtained per strain were then run on the same gel. Briefly, the procedure was as follows. After embedding the bacterial cells in agarose, the agarose blocks were incubated for 1 h in lysis solution containing lysozyme, mutanolysin, lysostaphin and RNase. This was followed by a 1-h proteinase K treatment. Then, slices were cut from the agarose blocks and washed for 15 min in TE buffer, these washes were repeated four times with fresh TE. After a 2-h restriction with SmaI, electrophoresis was carried out overnight. PMID:10397313

  16. Acoustic transfer of protein crystals from agarose pedestals to micromeshes for high-throughput screening

    SciTech Connect

    Cuttitta, Christina M.; Ericson, Daniel L.; Scalia, Alexander; Roessler, Christian G.; Teplitsky, Ella; Joshi, Karan; Campos, Olven; Agarwal, Rakhi; Allaire, Marc; Orville, Allen M.; Sweet, Robert M.; Soares, Alexei S.

    2015-01-01

    An acoustic high-throughput screening method is described for harvesting protein crystals and combining the protein crystals with chemicals such as a fragment library. Acoustic droplet ejection (ADE) is an emerging technology with broad applications in serial crystallography such as growing, improving and manipulating protein crystals. One application of this technology is to gently transfer crystals onto MiTeGen micromeshes with minimal solvent. Once mounted on a micromesh, each crystal can be combined with different chemicals such as crystal-improving additives or a fragment library. Acoustic crystal mounting is fast (2.33 transfers s{sup −1}) and all transfers occur in a sealed environment that is in vapor equilibrium with the mother liquor. Here, a system is presented to retain crystals near the ejection point and away from the inaccessible dead volume at the bottom of the well by placing the crystals on a concave agarose pedestal (CAP) with the same chemical composition as the crystal mother liquor. The bowl-shaped CAP is impenetrable to crystals. Consequently, gravity will gently move the crystals into the optimal location for acoustic ejection. It is demonstrated that an agarose pedestal of this type is compatible with most commercially available crystallization conditions and that protein crystals are readily transferred from the agarose pedestal onto micromeshes with no loss in diffraction quality. It is also shown that crystals can be grown directly on CAPs, which avoids the need to transfer the crystals from the hanging drop to a CAP. This technology has been used to combine thermolysin and lysozyme crystals with an assortment of anomalously scattering heavy atoms. The results point towards a fast nanolitre method for crystal mounting and high-throughput screening.

  17. Acoustic transfer of protein crystals from agarose pedestals to micromeshes for high-throughput screening

    SciTech Connect

    Cuttitta, Christina M.; Ericson, Daniel L.; Scalia, Alexander; Roessler, Christian G.; Teplitsky, Ella; Joshi, Karan; Campos, Olven; Agarwal, Rakhi; Allaire, Marc; Orville, Allen M.; Sweet, Robert M.; Soares, Alexei S.

    2014-06-01

    Acoustic droplet ejection (ADE) is an emerging technology with broad applications in serial crystallography such as growing, improving and manipulating protein crystals. One application of this technology is to gently transfer crystals onto MiTeGen micromeshes with minimal solvent. Once mounted on a micromesh, each crystal can be combined with different chemicals such as crystal-improving additives or a fragment library. Acoustic crystal mounting is fast (2.33 transfers s-1) and all transfers occur in a sealed environment that is in vapor equilibrium with the mother liquor. Here, a system is presented to retain crystals near the ejection point and away from the inaccessible dead volume at the bottom of the well by placing the crystals on a concave agarose pedestal (CAP) with the same chemical composition as the crystal mother liquor. The bowl-shaped CAP is impenetrable to crystals. Consequently, gravity will gently move the crystals into the optimal location for acoustic ejection. It is demonstrated that an agarose pedestal of this type is compatible with most commercially available crystallization conditions and that protein crystals are readily transferred from the agarose pedestal onto micromeshes with no loss in diffraction quality. It is also shown that crystals can be grown directly on CAPs, which avoids the need to transfer the crystals from the hanging drop to a CAP. This technology has been used to combine thermolysin and lysozyme crystals with an assortment of anomalously scattering heavy atoms. The results point towards a fast nanolitre method for crystal mounting and high-throughput screening.

  18. Acoustic transfer of protein crystals from agarose pedestals to micromeshes for high-throughput screening

    DOE PAGESBeta

    Cuttitta, Christina M.; Ericson, Daniel L.; Scalia, Alexander; Roessler, Christian G.; Teplitsky, Ella; Joshi, Karan; Campos, Olven; Agarwal, Rakhi; Allaire, Marc; Orville, Allen M.; et al

    2014-06-01

    Acoustic droplet ejection (ADE) is an emerging technology with broad applications in serial crystallography such as growing, improving and manipulating protein crystals. One application of this technology is to gently transfer crystals onto MiTeGen micromeshes with minimal solvent. Once mounted on a micromesh, each crystal can be combined with different chemicals such as crystal-improving additives or a fragment library. Acoustic crystal mounting is fast (2.33 transfers s-1) and all transfers occur in a sealed environment that is in vapor equilibrium with the mother liquor. Here, a system is presented to retain crystals near the ejection point and away from themore » inaccessible dead volume at the bottom of the well by placing the crystals on a concave agarose pedestal (CAP) with the same chemical composition as the crystal mother liquor. The bowl-shaped CAP is impenetrable to crystals. Consequently, gravity will gently move the crystals into the optimal location for acoustic ejection. It is demonstrated that an agarose pedestal of this type is compatible with most commercially available crystallization conditions and that protein crystals are readily transferred from the agarose pedestal onto micromeshes with no loss in diffraction quality. It is also shown that crystals can be grown directly on CAPs, which avoids the need to transfer the crystals from the hanging drop to a CAP. This technology has been used to combine thermolysin and lysozyme crystals with an assortment of anomalously scattering heavy atoms. The results point towards a fast nanolitre method for crystal mounting and high-throughput screening.« less

  19. Acoustic transfer of protein crystals from agarose pedestals to micromeshes for high-throughput screening

    PubMed Central

    Cuttitta, Christina M.; Ericson, Daniel L.; Scalia, Alexander; Roessler, Christian G.; Teplitsky, Ella; Joshi, Karan; Campos, Olven; Agarwal, Rakhi; Allaire, Marc; Orville, Allen M.; Sweet, Robert M.; Soares, Alexei S.

    2015-01-01

    Acoustic droplet ejection (ADE) is an emerging technology with broad applications in serial crystallography such as growing, improving and manipulating protein crystals. One application of this technology is to gently transfer crystals onto MiTeGen micromeshes with minimal solvent. Once mounted on a micromesh, each crystal can be combined with different chemicals such as crystal-improving additives or a fragment library. Acoustic crystal mounting is fast (2.33 transfers s−1) and all transfers occur in a sealed environment that is in vapor equilibrium with the mother liquor. Here, a system is presented to retain crystals near the ejection point and away from the inaccessible dead volume at the bottom of the well by placing the crystals on a concave agarose pedestal (CAP) with the same chemical composition as the crystal mother liquor. The bowl-shaped CAP is impenetrable to crystals. Consequently, gravity will gently move the crystals into the optimal location for acoustic ejection. It is demonstrated that an agarose pedestal of this type is compatible with most commercially available crystallization conditions and that protein crystals are readily transferred from the agarose pedestal onto micromeshes with no loss in diffraction quality. It is also shown that crystals can be grown directly on CAPs, which avoids the need to transfer the crystals from the hanging drop to a CAP. This technology has been used to combine thermolysin and lysozyme crystals with an assortment of anomalously scattering heavy atoms. The results point towards a fast nanolitre method for crystal mounting and high-throughput screening. PMID:25615864

  20. Idiots Savants: Retarded and Gifted.

    ERIC Educational Resources Information Center

    Yewchuk, Carolyn

    The paper reviews the paradoxical nature of idiots savants, persons who, although retarded, have exceptional skills in certain areas. Various explanations for the phenomenon are discussed, such as a specific genetic endowment, a specialized compensatory response to general intellectual deficiency, and possession of an eidetic memory. Various…

  1. Books for Mentally Retarded Children.

    ERIC Educational Resources Information Center

    Cincinnati - Hamilton County Public Library, OH.

    Presented is an annotated list of approximately 300 books for educable (EMR) and trainable mentally retarded (TMR) children and adolescents, 6 to 15 years of age. Books are arranged in the following groups for EMR students: Group I contains approximately 84 entries for students 6 to 9 years of age; Group II lists approximately 81 stories and books…

  2. Transportation and the Mentally Retarded.

    ERIC Educational Resources Information Center

    President's Committee on Mental Retardation, Washington, DC.

    Reported were the results of a contract that involved identification, description, and categorization of the nature of transportation problems for the mentally retarded by means of analysis of existing studies, two surveys, and an inventory of specialized programs and systems operating in the United States. One major problem was found to be…

  3. Detection of Malingered Mental Retardation

    ERIC Educational Resources Information Center

    Shandera, Anne L.; Berry, David T. R.; Clark, Jessica A.; Schipper, Lindsey J.; Graue, Lili O.; Harp, Jordan P.

    2010-01-01

    In a cross-validation of results from L. O. Graue et al. (2007), standard psychological assessment instruments, as well as tests of neurocognitive and psychiatric feigning, were administered under standard instructions to 24 participants diagnosed with mild mental retardation (MR) and 10 demographically matched community volunteers (CVH). A 2nd…

  4. Toilet Training the Retarded Child.

    ERIC Educational Resources Information Center

    Schwartz, Jeffrey K.

    The booklet offers guidelines in both Spanish and English to parents who are toilet training a mentally retarded child. The toilet training process is broken down into tasks that the child must learn, and the importance of positive reinforcement for each successfully accomplished task is emphasized. It is recommended that parents keep charts…

  5. HANDBOOK OF MENTAL RETARDATION SYNDROMES.

    ERIC Educational Resources Information Center

    CARTER, CHARLES H.

    THE CLINICAL SYNDROMES WHICH CONTRIBUTE TO THE PRODUCTION OF MENTAL RETARDATION ARE DESCRIBED BY SIGNS, SYMPTOMS, AND ETIOLOGY. SYNDROMES TREATED ARE (1) PRENATAL AND POSTNATAL INFECTIONS, (2) PRENATAL INTOXICATION AND ALLERGIC REACTIONS, (3) PRENATAL TRAUMA, PHYSICAL AGENTS, OR INTOXICATION, (4) BIRTH INJURIES, (5) POSTNATAL POISONS AND ALLERGIC…

  6. Dichotic Stimulation and Mental Retardation.

    ERIC Educational Resources Information Center

    Mosley, James L.; Virbancic, Mirna I.

    1990-01-01

    This paper reviews literature on the use of dichotic stimulation in individuals with mental retardation, and examines how noninvasive dichotic stimulation relates to hemisphere lateralization. Common findings are discussed concerning direction and magnitude of ear asymmetries, patterns of intrusion errors, and speech lateralization of Down…

  7. Genetic Counseling in Mental Retardation.

    ERIC Educational Resources Information Center

    Bowen, Peter

    The task of the genetic counselor who identifies genetic causes of mental retardation and assists families to understand risk of recurrence is described. Considered are chromosomal genetic disorders such as Down's syndrome, inherited disorders such as Tay-Sachs disease, identification by testing the amniotic fluid cells (amniocentresis) in time…

  8. Fire-retardant epoxy polymers

    NASA Technical Reports Server (NTRS)

    Akawie, R. I.; Bilow, N.; Giants, T. W.

    1978-01-01

    Phosphorus atoms in molecular structure of epoxies make them fire-retardant without degrading their adhesive strength. Moreover, polymers are transparent, unlike compounds that contain arsenic or other inorganics. They have been used to bond polyvinylfluoride and polyether sulfone films onto polyimide glass laminates.

  9. Mental Retardation: Diagnosis and Treatment.

    ERIC Educational Resources Information Center

    Poser, Charles M., Ed.

    A collection of writings by 17 authors, the text includes the following discussions: general principles of diagnosis and management of mental retardation, neurologic evaluation of the infant and child, psychological evaluation, educational information, and treatment of pseudoretardation, communicative disorders, and metabolic and endocrine causes.…

  10. VOCATIONAL PROGRAMMING FOR THE RETARDED.

    ERIC Educational Resources Information Center

    BRICE, CARL R.

    A SUCCESSFUL PROGRAM OF VOCATIONAL TRAINING FOR THE MENTALLY RETARDED IS BEING CARRIED ON AT THE MADISON (WISCONSIN) VOCATIONAL, TECHNICAL, AND ADULT SCHOOLS. THE TRAINEES MUST BE 17 YEARS OR OLDER, WITH AN IQ OF APPROXIMATELY 50-75. THE SCHOOL OF QUANTITY FOOD PREPARATION CONTRIBUTES GREATLY TO THIS PROGRAM, FOR WHILE IT MAINLY TEACHES CHEFS AND…

  11. The Supreme Court V. Retarded Children.

    ERIC Educational Resources Information Center

    Biklen, Douglas

    1981-01-01

    The author examines the Supreme Court decisions regarding the rights of retarded children not to be institutionalized and rights of retarded people to have aggressive medical treatment that will help prolong their lives. (SB)

  12. Viscoelastic Properties of Vitreous Gel

    NASA Astrophysics Data System (ADS)

    Pirouz Kavehpour, H.; Sharif-Kashani, Pooria

    2010-11-01

    We studied the rheological properties of porcine vitreous humor using a stressed-control shear rheometer. All experiments were performed in a closed environment at body temperature to mimic in-vivo conditions. We modeled the creep deformation using a two-element retardation spectrum model. By associating each element of the model to an individual biopolymeric system in the vitreous gel, a separate response to the applied stress was obtained from each component. The short time scale was associated with the collagen structure, while the longer time scale was related to the microfibrilis and hyaluronan network. We were able to distinguish the role of each main component from the overall rheological properties. Knowledge of this correlation enables us to relate the physical properties of vitreous to its pathology, as well as optimize surgical procedures such as vitrectomy.

  13. Rehearsal Capacity and Dimensional Independence in Retardates

    ERIC Educational Resources Information Center

    McBane, Bonnie M.

    1976-01-01

    Retardate use of retention strategies and the independence of color and form retention were compared with predictions of the Attention-Retention theory of retardate discrimination learning. Institutional retardates were selected from two MA ranges, 6 to 8 and 9 to 12 years, without regard to diagnostic categories. (Author/JH)

  14. Endocrine Disorders Associated with Mental Retardation

    PubMed Central

    Reddy, Churku Mohan

    1980-01-01

    Endocrine disorders associated with mental retardation are described in relation to clinical characteristics, pathogenesis, diagnostic procedures, and treatment. Some endocrine disorders, particularly hypothyroidism, nephrogenic-diabetes insipidus, and hypoglycemic conditions, are frequently associated with mental retardation. Early diagnosis and prompt and proper management reduce mortality and the incidence of mental retardation associated with endocrine disorders. PMID:7392067

  15. Low Elevated Lead Levels and Mental Retardation.

    ERIC Educational Resources Information Center

    Marlowe, Mike; And Others

    The relationship between low elevated lead absorption and mild mental retardation was investigated in 40 rural children (preschool to grade 12) without demonstrable cause for their retardation. Trace mineral analysis of hair samples from Ss and a control group (N=20) indicated the mean hair lead concentrations for the retarded Ss were considerably…

  16. Mental Retardation: Prevention Strategies That Work.

    ERIC Educational Resources Information Center

    President's Committee on Mental Retardation, Washington, DC.

    The report by the President's Committee on Mental Retardation reviews the current state of knowledge in the area of biological and environmental prevention of mental retardation and describes programs on the frontiers of research or service delivery. Section I examines programs that are effectively preventing mental retardation through biomedical…

  17. THE TEACHER OF THE MENTALLY RETARDED.

    ERIC Educational Resources Information Center

    CHARNEY, LEON; LACROSSE, EDWARD

    BASIC INFORMATION IS PROVIDED FOR PROSPECTIVE TEACHERS OF MENTALLY RETARDED CHILDREN. THE FIRST FOUR CHAPTERS ARE DEVOTED TO CLASSROOM CONDITIONS, PARENTAL ATTITUDES, AND TEACHER-PUPIL INTERACTION IN THE SPECIAL CLASS FOR RETARDATES. CHAPTER ONE GIVES A GENERAL DESCRIPTION OF THE MENTALLY RETARDED CHILD AS HE APPEARS TO THE TEACHER. CHAPTER TWO…

  18. Gel Electrophoresis of DNA --- New Measurements and the Repton Model at High Fields

    NASA Astrophysics Data System (ADS)

    Krawczyk, M. J.; Pasciak, P.; Dydejczyk, A.; Kulakowski, K.; Dulak, J.

    2005-05-01

    New experimental data are presented on the gel electrophoresis of DNA. Experiment was made for molecules of length 173 kbp, in 1 percent agarose gel, in TAE 1 × buffer and the field intensity between 5 and 9 V/cm. The results are compared with our computer simulations, performed within the repton model of Duke and Rubinstein. The ranges of field and molecule length are determined, where the geometration effect appears. We investigate also the field dependence of the velocity and the diffusion coefficient at the border of the geometration regime.

  19. Agarose microwell based neuronal micro-circuit arrays on microelectrode arrays for high throughput drug testing.

    PubMed

    Kang, Gyumin; Lee, Ji-Hye; Lee, Chang-Soo; Nam, Yoonkey

    2009-11-21

    For cell-based biosensor applications, dissociated neurons have been cultured on planar microelectrode arrays (MEAs) to measure the network activity with substrate-embedded microelectrodes. There has been a need for a multi-well type platform to reduce the data collection time and increase the statistical power for data analysis. This study presents a novel method to convert a conventional MEA into a multi-well MEA with an array of micrometre-sized neuronal culture ('neuronal micro-circuit array'). An MEA was coated first with cell-adhesive layer (poly-D-lysine) which was subsequently patterned with a cell-repulsive layer (agarose hydrogel) to both pattern the cell adhesive region and isolate neuronal micro-circuits from each other. For a few weeks, primary hippocampal neurons were cultured on the agarose microwell MEA and the development of spontaneous electrical activities were characterized with extracellular action potentials. Using neurotransmission modulators, the simultaneous monitoring of drug responses from neuronal micro-circuit arrays was also demonstrated. The proposed approach will be powerful for neurobiological functional assay studies or neuron-based biosensor fields which require repeated trials to obtain a single data point due to biological variations. PMID:19865730

  20. Simulated moving bed separation of agarose-hydrolyzate components for biofuel production from marine biomass.

    PubMed

    Kim, Pung-Ho; Nam, Hee-Geun; Park, Chanhun; Wang, Nien-Hwa Linda; Chang, Yong Keun; Mun, Sungyong

    2015-08-01

    The economically-efficient separation of galactose, levulinic acid (LA), and 5-hydroxymethylfurfural (5-HMF) in acid hydrolyzate of agarose has been a key issue in the area of biofuel production from marine biomass. To address this issue, an optimal simulated moving bed (SMB) process for continuous separation of the three agarose-hydrolyzate components with high purities, high yields, and high throughput was developed in this study. As a first step for this task, the adsorption isotherm and mass-transfer parameters of each component on the qualified adsorbent were determined through a series of multiple frontal experiments. The determined parameters were then used in optimizing the SMB process for the considered separation. Finally, the optimized SMB process was tested experimentally using a self-assembled SMB unit with four zones. The SMB experimental results and the relevant computer simulations verified that the developed process in this study was quite successful in the economically-efficient separation of galactose, LA, and 5-HMF in a continuous mode with high purities and high yields. It is thus expected that the developed SMB process in this study will be able to serve as one of the trustworthy ways of improving the economic feasibility of biofuel production from marine biomass. PMID:26141276

  1. A Novel Agarolytic β-Galactosidase Acts on Agarooligosaccharides for Complete Hydrolysis of Agarose into Monomers

    PubMed Central

    Lee, Chan Hyoung; Kim, Hee Taek; Yun, Eun Ju; Lee, Ah Reum; Kim, Sa Rang; Kim, Jae-Han; Choi, In-Geol

    2014-01-01

    Marine red macroalgae have emerged to be renewable biomass for the production of chemicals and biofuels, because carbohydrates that form the major component of red macroalgae can be hydrolyzed into fermentable sugars. The main carbohydrate in red algae is agarose, and it is composed of d-galactose and 3,6-anhydro-l-galactose (AHG), which are alternately bonded by β1-4 and α1-3 linkages. In this study, a novel β-galactosidase that can act on agarooligosaccharides (AOSs) to release galactose was discovered in a marine bacterium (Vibrio sp. strain EJY3); the enzyme is annotated as Vibrio sp. EJY3 agarolytic β-galactosidase (VejABG). Unlike the lacZ-encoded β-galactosidase from Escherichia coli, VejABG does not hydrolyze common substrates like lactose and can act only on the galactose moiety at the nonreducing end of AOS. The optimum pH and temperature of VejABG on an agarotriose substrate were 7 and 35°C, respectively. Its catalytic efficiency with agarotriose was also similar to that with agaropentaose or agaroheptaose. Since agarotriose lingers as the unreacted residual oligomer in the currently available saccharification system using β-agarases and acid prehydrolysis, the agarotriose-hydrolyzing capability of this novel β-galactosidase offers an enormous advantage in the saccharification of agarose or agar in red macroalgae for its use as a biomass feedstock for fermentable sugar production. PMID:25038102

  2. Method for trapping affinity chromatography of transcription factors using aldehyde-hydrazide coupling to agarose.

    PubMed

    Jia, Yinshan; Jarrett, Harry W

    2015-08-01

    The use of a method of coupling DNA was investigated for trapping and purifying transcription factors. Using the GFP-C/EBP (CAAT/enhancer binding protein) fusion protein as a model, trapping gives higher purity and comparable yield to conventional affinity chromatography. The chemistry used is mild and was shown to have no detrimental effect on GFP fluorescence or GFP-C/EBP DNA binding. The method involves introducing a ribose nucleotide to the 3' end of a DNA sequence. Reaction with mM NaIO4 (sodium metaperiodate) produces a dialdehyde of ribose that couples to hydrazide-agarose. The DNA is combined at nM concentration with a nuclear extract or other protein mixture, and DNA-protein complexes form. The complex is then coupled to hydrazide-agarose for trapping the DNA-protein complex and the protein eluted by increasing NaCl concentration. Using a different oligonucleotide with the proximal E-box sequence from the human telomerase promoter, USF-2 transcription factor was purified by trapping, again with higher purity than results from conventional affinity chromatography and similar yield. Other transcription factors binding E-boxes, including E2A, c-Myc, and Myo-D, were also purified, but myogenin and NFκB were not. Therefore, this approach proved to be valuable for both affinity chromatography and the trapping approach. PMID:25935261

  3. Method for trapping affinity chromatography of transcription factors using aldehyde-hydrazide coupling to agarose

    PubMed Central

    Jia, Yinshan; Jarrett, Harry W.

    2015-01-01

    The uses of a method of coupling DNA is investigated for trapping and purifying transcription factors. Using the GFP-C/EBP fusion protein as a model, trapping gives higher purity and comparable yield to conventional affinity chromatography. The chemistry utilized is mild and was shown to have no detrimental effect on GFP fluorescence or GFP-C/EBP DNA-binding. The method involves introducing a ribose nucleotide to the 3′ end of a DNA sequence. Reaction with mM NaIO4 (sodium metaperiodate) produces a dialdehyde of ribose which couples to hydrazide-agarose. The DNA is combined at nM concentration with a nuclear extract or other protein mixture and DNA-protein complexes form. The complex is then coupled to hydrazide-agarose for trapping the DNA-protein complex and the protein eluted by increasing NaCl concentration. Using a different oligonucleotide with the proximal E-box sequence from the human telomerase promoter, USF-2 transcription factor was purified by trapping, again with higher purity than results from conventional affinity chromatography and similar yield. Other transcription factors binding E-boxes including E2A, c-myc, and myo-D were also purified but myogenenin and NFκB were not. Therfore, this approach proved valuable for both affinity chromatography and for the trapping approach. PMID:25935261

  4. Finite difference time domain model of ultrasound propagation in agarose scaffold containing collagen or chondrocytes.

    PubMed

    Inkinen, Satu I; Liukkonen, Jukka; Malo, Markus K H; Virén, Tuomas; Jurvelin, Jukka S; Töyräs, Juha

    2016-07-01

    Measurement of ultrasound backscattering is a promising diagnostic technique for arthroscopic evaluation of articular cartilage. However, contribution of collagen and chondrocytes on ultrasound backscattering and speed of sound in cartilage is not fully understood and is experimentally difficult to study. Agarose hydrogels have been used in tissue engineering applications of cartilage. Therefore, the aim of this study was to simulate the propagation of high frequency ultrasound (40 MHz) in agarose scaffolds with varying concentrations of chondrocytes (1 to 32 × 10(6) cells/ml) and collagen (1.56-200 mg/ml) using transversely isotropic two-dimensional finite difference time domain method (FDTD). Backscatter and speed of sound were evaluated from the simulated pulse-echo and through transmission measurements, respectively. Ultrasound backscatter increased with increasing collagen and chondrocyte concentrations. Furthermore, speed of sound increased with increasing collagen concentration. However, this was not observed with increasing chondrocyte concentrations. The present study suggests that the FDTD method may have some applicability in simulations of ultrasound scattering and propagation in constructs containing collagen and chondrocytes. Findings of this study indicate the significant role of collagen and chondrocytes as ultrasound scatterers and can aid in development of modeling approaches for understanding how cartilage architecture affects to the propagation of high frequency ultrasound. PMID:27475127

  5. Pravastatin Improves Glucose Regulation and Biocompatibility of Agarose Encapsulated Porcine Islets following Transplantation into Pancreatectomized Dogs

    PubMed Central

    Gazda, Lawrence S.; Vinerean, Horatiu V.; Laramore, Melissa A.; Hall, Richard D.; Carraway, Joseph W.; Smith, Barry H.

    2014-01-01

    The encapsulation of porcine islets is an attractive methodology for the treatment of Type I diabetes. In the current study, the use of pravastatin as a mild anti-inflammatory agent was investigated in pancreatectomized diabetic canines transplanted with porcine islets encapsulated in agarose-agarose macrobeads and given 80 mg/day of pravastatin (n = 3) while control animals did not receive pravastatin (n = 3). Control animals reached preimplant insulin requirements on days 18, 19, and 32. Pravastatin-treated animals reached preimplant insulin requirements on days 22, 27, and 50. Two animals from each group received a second macrobead implant: control animals remained insulin-free for 15 and 21 days (AUC = 3003 and 5078 mg/dL/24 hr days 1 to 15) and reached preimplant insulin requirements on days 62 and 131. Pravastatin treated animals remained insulin-free for 21 and 34 days (AUC = 1559 and 1903 mg/dL/24 hr days 1 to 15) and reached preimplant insulin requirements on days 38 and 192. Total incidence (83.3% versus 64.3%) and total severity (22.7 versus 18.3) of inflammation on tissue surfaces were higher in the control group at necropsy. These findings support pravastatin therapy in conjunction with the transplantation of encapsulated xenogeneic islets for the treatment of diabetes mellitus. PMID:24963494

  6. Effect of the hydration on the biomechanical properties in a fibrin-agarose tissue-like model.

    PubMed

    Scionti, Giuseppe; Moral, Monica; Toledano, Manuel; Osorio, Raquel; Durán, Juan D G; Alaminos, Miguel; Campos, Antonio; López-López, Modesto T

    2014-08-01

    The effect of hydration on the biomechanical properties of fibrin and fibrin-agarose (FA) tissue-like hydrogels is reported. Native hydrogels with approximately 99.5% of water content and hydrogels with water content reduced until 90% and 80% by means of plastic compression (nanostructuration) were generated. The biomechanical properties of the hydrogels were investigated by tensile, compressive, and shear tests. Experimental results indicate that nanostructuration enhances the biomechanical properties of the hydrogels. This improvement is due to the partial draining of the water that fills the porous network of fibers that the plastic compression generates, which produces a denser material, as confirmed by scanning electron microscopy. Results also indicate that the characteristic compressive and shear parameters increase with agarose concentration, very likely due to the high water holding capacity of agarose, which reduces the compressibility and gives consistency to the hydrogels. However, results of tensile tests indicate a weakening of the hydrogels as agarose concentration increases, which evidences the anisotropic nature of these biomaterials. Interestingly, we found that by adjusting the water and agarose contents it is possible to tune the biomechanical properties of FA hydrogels for a broad range, within which the properties of many native tissues fall. PMID:23963645

  7. High-density small-volume gel loading directly from capillary tubes.

    PubMed

    Evensen, H T; Meldrum, D R; Saenphimmachak, C; Dixon, E E

    1999-11-01

    A technique has been developed for high lane density loading of small-volume DNA samples in a horizontal agarose gel. This technique has been investigated with a simple hand-held tool that is made to couple to sample output from a new capillary-based sample automation system. The approach consists of piercing the gel with pressurized sample capillaries and relieving the pressure shortly before withdrawal. The pressurization prevents the capillary from aspirating the gel buffer and keeps the sample at the tip of the capillary, so that it may be sucked into the gel during withdrawal. This method is shown to be adequate for a wide range of DNA ladders and PCR-based screening. In addition to allowing smaller lanes and a higher lane density than is achievable with traditional well-forming techniques, it relaxes the need for well formation and the alignment of the sample loader with those wells, providing an easy, efficient means of loading agarose gels. PMID:10572646

  8. Propagation and Separation of Charged Colloids by Cylindrical Passivated Gel Electrophoresis.

    PubMed

    Bikos, Dimitri; Mason, Thomas G

    2016-07-01

    We explore the electrophoretic propagation of charged colloidal objects, monodisperse anionically stabilized polystyrene spheres, in large-pore agarose gels that have been passivated using polyethylene glycol (PEG) when a radial electric field is applied in a cylindrical geometry. By contrast to standard Cartesian gel-electrophoresis geometries, in a cylindrical geometry, charged particles that start at a ring well near the central axis propagate outward more rapidly initially and then slow down as they move further away from the axis. By building a full-ring cylindrical gel electrophoresis chamber and taking movies of scattered light from propagating nanospheres undergoing electrophoresis, we experimentally demonstrate that the ring-like front of monodisperse nanospheres propagates stably in PEG-passivated agarose gels and that the measured ring radius as a function of time agrees with a simple model that incorporates the electric field of a cylindrical geometry. Moreover, we show that this cylindrical geometry offers a potential advantage when performing electrophoretic separations of objects that have widely different sizes: smaller objects can still be retained in a cylindrical gel that has a limited size over long electrophoretic run times required for separating larger objects. PMID:27109865

  9. [Sterilization of mentally retarded women].

    PubMed

    Heidenreich, W; Petersen, P; Schneider, J

    1982-07-01

    Seven mentally retarded women were sterilized in the Department of Obstetrics and Gynaecology of Medical School Hannover between 1.6.74 and 1.6.81. The decision to operate proceeded only after careful consideration by the director of the clinic. Each case was documented with proof that improvement of the mental situation was unprobable and that sterilization seemed highly desirable. In spite of strong reservation the sterilization of a mentally retarded may medically and ethically be justified in exceptional cases. The operation seems possible by the following: The sterilization may only be performed if the patient does not obviously refuse it. Diagnosis and prognosis of the mental handicap must undoubtedly be proven. If the patient cannot judge the consequence of the operation the legal guardian must decide for her. The court must consent in these cases. Regarding legal theory the decision by the guardian is an open question. PMID:6922080

  10. [Concentration and emission fluxes of halogenated flame retardants in sewage from sewage outlet in Dongjiang River].

    PubMed

    Zeng, Yan-Hong; Luo, Xiao-Jun; Sun, Yu-Xin; Yu, Le-Huan; Chen, She-Jun; Mai, Bi-Xian

    2011-10-01

    Fourteen sewage samples from sewage outlets in Dongjiang River were collected. Halogented flame retardants were extracted and purified using dichloromethane and alumina/silica-gel column, respectively. The concentrations of halogenated flame retardants were measured utilizing GC/MS, and the emission fluxes were estimated. Decabromodiphenyl ethane (DBDPE) was the predominant halogenated pollutant (accounting for 64%) in sewage with the concentration ranging from 9.1 ng/L to 990 ng/L. The concentrations of polybrominated biphenyl ether (PBDEs), dominated by BDE209, in the sewage ranged from 6.9 ng/L to 470 ng/L, accounting for 30% of total halogenated flame retardants. The concentrations of other flame retardants, such as dechlorane plus (DP), 1, 2-bis(2, 4, 6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), and pentabromotoluene (PBT), were ranged within 0.17-23.6, nd-26.3, nd-1.45 and nd-0.45 ng/L, respectively. The concentrations of PBDEs in sewage of Dongjiang River were comparable to those in influent wastewater of sewage treatment plants of Guangzhou, suggesting that the wastewater was discharged directly into Dongjiang River without any treatment. The emission flux of halogenated flame retardants from sewage was 191 kg. Emission from industrial wastewater, contributed to 48%-91% of total emission, was the main source of halogenated flame retardants. PMID:22279897

  11. Fire-Retardant Polymeric Additives

    NASA Technical Reports Server (NTRS)

    Williams, Martha K.; Smith, Trent M.

    2011-01-01

    Polyhydroxyamide (PHA) and polymethoxyamide (PMeOA) are fire-retardant (FR) thermoplastic polymers and have been found to be useful as an additive for imparting fire retardant properties to other compatible, thermoplastic polymers (including some elastomers). Examples of compatible flammable polymers include nylons, polyesters, and acrylics. Unlike most prior additives, PHA and PMeOA do not appreciably degrade the mechanical properties of the matrix polymer; indeed, in some cases, mechanical properties are enhanced. Also, unlike some prior additives, PHA and PMeOA do not decompose into large amounts of corrosive or toxic compounds during combustion and can be processed at elevated temperatures. PMeOA derivative formulations were synthesized and used as an FR additive in the fabrication of polyamide (PA) and polystyrene (PS) composites with notable reduction (>30 percent for PS) in peak heat release rates compared to the neat polymer as measured by a Cone Calorimeter (ASTM E1354). Synergistic effects were noted with nanosilica composites. These nanosilica composites had more than 50-percent reduction in peak heat release rates. In a typical application, a flammable thermoplastic, thermoplastic blend, or elastomer that one seeks to render flame-retardant is first dry-mixed with PHA or PMeOA or derivative thereof. The proportion of PHA or PMeOA or derivative in the mixture is typically chosen to lie between 1 and 20 weight percent. The dry blend can then be melt-extruded. The extruded polymer blend can further be extruded and/or molded into fibers, pipes, or any other of a variety of objects that may be required to be fire-retardant. The physical and chemical mechanisms which impart flame retardancy of the additive include inhibiting free-radical oxidation in the vapor phase, preventing vaporization of fuel (the polymer), and cooling through the formation of chemical bonds in either the vapor or the condensed phase. Under thermal stress, the cyclic hydroxyl/ methoxy

  12. Microfluidic dielectrophoretic sorter using gel vertical electrodes

    PubMed Central

    Luo, Jason; Nelson, Edward L.; Li, G. P.; Bachman, Mark

    2014-01-01

    We report the development and results of a two-step method for sorting cells and small particles in a microfluidic device. This approach uses a single microfluidic channel that has (1) a microfabricated sieve which efficiently focuses particles into a thin stream, followed by (2) a dielectrophoresis (DEP) section consisting of electrodes along the channel walls for efficient continuous sorting based on dielectric properties of the particles. For our demonstration, the device was constructed of polydimethylsiloxane, bonded to a glass surface, and conductive agarose gel electrodes. Gold traces were used to make electrical connections to the conductive gel. The device had several novel features that aided performance of the sorting. These included a sieving structure that performed continuous displacement of particles into a single stream within the microfluidic channel (improving the performance of downstream DEP, and avoiding the need for additional focusing flow inlets), and DEP electrodes that were the full height of the microfluidic walls (“vertical electrodes”), allowing for improved formation and control of electric field gradients in the microfluidic device. The device was used to sort polymer particles and HeLa cells, demonstrating that this unique combination provides improved capability for continuous DEP sorting of particles in a microfluidic device. PMID:24926390

  13. 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.

  14. A least-squares error minimization approach in the determination of ferric ion diffusion coefficient of Fricke-infused dosimeter gels

    SciTech Connect

    Tseng, Y.J.; Huang, S.-C.; Chu, W.C.

    2005-04-01

    A least-squares error minimization approach was adopted to assess ferric ion diffusion coefficient of Fricke-agarose gels. Ferric ion diffusion process was modeled as a Gaussian-shaped degradation kernel operating on an initial concentration distribution. Diffusion coefficient was iteratively determined by minimizing the error function defined as the difference between the theoretically calculated and the experimentally measured dose distributions. A rapid MR image-based differential gel dosimetry technique that time resolves the evolution of the ferric ion diffusion process minimizes smearing of the dose distribution. Our results showed that for a Fricke-agarose gel contained 1 mM ammonium ferrous sulfate, 1% agarose, 1 mM sodium chloride, and 50 mM sulfuric acid, its ferric ion diffusion coefficient is (1.59{+-}0.28)x10{sup -2} cm{sup 2} h{sup -1} at room temperature. This value falls within the 1.00-2.00x10{sup -2} cm{sup 2} h{sup -1} range previously reported under varying gelling ingredients and concentrations. This method allows a quick, nondestructive evaluation of the ferric ion diffusion coefficient that can be used in conjunction with the in situ gel dosimetry experiment to provide a practical diffusion characterization of the dosimeter gel.

  15. Binding of regulatory subunits of cyclic AMP-dependent protein kinase to cyclic CMP agarose.

    PubMed

    Hammerschmidt, Andreas; Chatterji, Bijon; Zeiser, Johannes; Schröder, Anke; Genieser, Hans-Gottfried; Pich, Andreas; Kaever, Volkhard; Schwede, Frank; Wolter, Sabine; Seifert, Roland

    2012-01-01

    The bacterial adenylyl cyclase toxins CyaA from Bordetella pertussis and edema factor from Bacillus anthracis as well as soluble guanylyl cyclase α(1)β(1) synthesize the cyclic pyrimidine nucleotide cCMP. These data raise the question to which effector proteins cCMP binds. Recently, we reported that cCMP activates the regulatory subunits RIα and RIIα of cAMP-dependent protein kinase. In this study, we used two cCMP agarose matrices as novel tools in combination with immunoblotting and mass spectrometry to identify cCMP-binding proteins. In agreement with our functional data, RIα and RIIα were identified as cCMP-binding proteins. These data corroborate the notion that cAMP-dependent protein kinase may serve as a cCMP target. PMID:22808067

  16. Delivery of DNA vaccines by agarose hydrogel implants facilitates genetic immunization in cattle.

    PubMed

    Toussaint, J F; Dubois, A; Dispas, M; Paquet, D; Letellier, C; Kerkhofs, P

    2007-01-26

    The present study demonstrates the interest of two slow-release systems as vaccination tools in cattle. Two experiments show that a first intradermal administration of one DNA vaccine dose combined with the slow-release of a second dose conduct to a priming of the bovine herpesvirus 1-specific immune response similar to the one generated by two discrete administrations 4 weeks apart. The first experiment demonstrates the efficacy of the slow-release system with well-characterized Alzet osmotic pumps, whereas the second experiment extends the same concept with innovative agarose hydrogel implants. These latter implants are cheaper and more convenient than the osmotic pumps or repeated intradermal administrations since they contribute to an efficient priming of the immune response in a single manipulation of the animals. PMID:17084488

  17. Multi-featured macroporous agarose-alginate cryogel: synthesis and characterization for bioengineering applications.

    PubMed

    Tripathi, Anuj; Kumar, Ashok

    2011-01-10

    In this study agarose-alginate scaffolds are synthesized using cryogelation technology in different formats like monolith, sheet, discs, and beads, and show amiable mechanical strength like soft tissue properties and high interconnected macroporous degradable architecture. In cell-material interactions, fibroblast (NIH-3T3) cells showed good adherence and proliferation on these scaffolds presenting its potential application in soft tissue engineering. The application of cryogel beads and monoliths was also examined by the efficient immobilization of bacterial cells (BL21) on these matrices revealing their use for recovery of product from continuous fermentation systems without cell leakage. These scaffolds also showed potential as a filter for repeated recovery of heavy metal binding, such as copper and nickel from the waste water. The cryogels prepared herein do have a number of unique features that make them an important class of soft materials for developing multi-featured scaffolds as a novel carrier for bioengineering applications. PMID:21077225

  18. Biomechanical Conditioning Enhanced Matrix Synthesis in Nucleus Pulposus Cells Cultured in Agarose Constructs with TGFβ

    PubMed Central

    Tilwani, Reshma K.; Bader, Dan L.; Chowdhury, Tina T.

    2012-01-01

    Biomechanical signals play an important role in normal disc metabolism and pathology. For instance, nucleus pulposus (NP) cells will regulate metabolic activities and maintain a balance between the anabolic and catabolic cascades. The former involves factors such as transforming growth factor-β (TGFβ) and mechanical stimuli, both of which are known to regulate matrix production through autocrine and paracrine mechanisms. The present study examined the combined effect of TGFβ and mechanical loading on anabolic activities in NP cells cultured in agarose constructs. Stimulation with TGFβ and dynamic compression reduced nitrite release and increased matrix synthesis and gene expression of aggrecan and collagen type II. The findings from this work has the potential for developing regenerative treatment strategies which could either slow down or stop the degenerative process and/or promote healing mechanisms in the intervertebral disc. PMID:24956513

  19. Stabilization of a formate dehydrogenase by covalent immobilization on highly activated glyoxyl-agarose supports.

    PubMed

    Bolivar, Juan M; Wilson, Lorena; Ferrarotti, Susana Alicia; Fernandez-Lafuente, Roberto; Guisan, Jose M; Mateo, Cesar

    2006-03-01

    Formate dehydrogenase (FDH) is a stable enzyme that may be readily inactivated by the interaction with hydrophobic interfaces (e.g., due to strong stirring). This may be avoided by immobilizing the enzyme on a porous support by any technique. Thus, even if the enzyme is going to be used in an ultra-membrane reactor, the immobilization presents some advantages. Immobilization on supports activated with bromocianogen, polyethylenimine, glutaraldehyde, etc., did not promote any stabilization of the enzyme under thermal inactivation. However, the immobilization of FDH on highly activated glyoxyl agarose has permitted increasing the enzyme stability against any distorting agent: pH, T, organic solvent, etc. The time of support-enzyme reaction, the temperature of immobilization, and the activation of the support need to be optimized to get the optimal stability-activity properties. Optimized biocatalyst retained 50% of the offered activity and became 50 times more stable at high temperature and neutral pH. Moreover, the quaternary structure of this dimeric enzyme becomes stabilized by immobilization under optimized conditions. Thus, at acidic pH (conditions where the subunit dissociation is the first step in the enzyme inactivation), the immobilization of both subunits of the enzyme on glyoxyl-agarose has allowed the enzyme to be stabilized by hundreds of times. Moreover, the optimal temperature of the enzyme has been increased (even by 10 degrees C at pH 4.5). Very interestingly, the activity with NAD(+)-dextran was around 60% of that observed with free cofactor. PMID:16529396

  20. Purification of CD47-streptavidin fusion protein from bacterial lysate using biotin-agarose affinity chromatography.

    PubMed

    Salehi, Nasrin; Peng, Ching-An

    2016-07-01

    CD47 is a widely expressed transmembrane glycoprotein that modulates the activity of a plethora of immune cells via its extracellular domain. Therefore, CD47 plays important roles in the regulation of immune responses and may serve as targets for the development of immunotherapeutic agents. To make sure CD47 functionality is intact under the process of protein conjugation, CD47-streptavidin fusion protein was expressed and purified because it can easily bind to biotin-tagged materials via the unique biotin-streptavidin affinity. In this study, gene sequences of CD47 extracellular domain (CD47ECD) and core streptavidin (coreSA) with a total 834 bp were inserted into pET20b plasmid to construct recombinant plasmid encoding CD47-SA fusion gene. After bacteria transformation, the CD47-SA fusion protein was expressed by isopropyl-β-d-thiogalactopyranoside (IPTG) induction. The collected bacteria lysate was loaded on biotinylated agarose to proceed the purification of CD47-SA fusion protein. Due to the unexpected high affinity between biotin and coreSA, standard washing and elution approaches (e.g., varying pH, using biotin, and applying guanidine hydrochloride) reported for biotin-streptavidin affinity chromatography were not able to separate the target fusion protein. Instead, using low concentration of the non-ionic detergent Triton X-100 followed with alkaline buffer could efficiently weaken the binding between biotin and coreSA, thereby eluting out CD47-SA fusion protein from the biotin agarose column. The purified CD47-SA fusion protein was further characterized by molecular biology methods and its antiphagocytic functionality was confirmed by the phagocytosis assay. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:949-958, 2016. PMID:27110670

  1. Analysis of rRNA Gene Methylation in Arabidopsis thaliana by CHEF-Conventional 2D Gel Electrophoresis.

    PubMed

    Mohannath, Gireesha; Pikaard, Craig S

    2016-01-01

    Contour-clamped homogenous electric field (CHEF) gel electrophoresis, a variant of Pulsed-field gel electrophoresis (PFGE), is a powerful technique for resolving large fragments of DNA (10 kb-9 Mb). CHEF has many applications including the physical mapping of chromosomes, artificial chromosomes, and sub-chromosomal DNA fragments, etc. Here, we describe the use of CHEF and two-dimensional gel electrophoresis to analyze rRNA gene methylation patterns within the two ~4 million base pair nucleolus organizer regions (NORs) of Arabidopsis thaliana. The method involves CHEF gel electrophoresis of agarose-embedded DNA following restriction endonuclease digestion to cut the NORs into large but resolvable segments, followed by digestion with methylation-sensitive restriction endonucleases and conventional (or CHEF) gel electrophoresis, in a second dimension. Resulting products are then detected by Southern blotting or PCR analyses capable of discriminating rRNA gene subtypes. PMID:27576719

  2. Fire retardancy using applied materials

    NASA Technical Reports Server (NTRS)

    Feldman, R.

    1971-01-01

    An example of advanced technology transfer from the Little Joe, Surveyor, Comsat, re-entry and Apollo age to everyday fire protection needs is presented. Utilizing the principle of sublimation cooling for thermostatic temperature control, the material meets a wide range of fire retardancy and heat transmission control requirements. Properties vary from flexible tape for conduits and electrical cables to rigid coatings for column protection, with a broad spectrum of sublimation temperatures available. The material can be applied in the field or in the factory, utilizing mass production techniques, yielding a product that is reliable, effective, widely available and low in cost.

  3. 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 ...

  4. Ag@AgI, core@shell structure in agarose matrix as hybrid: synthesis, characterization, and antimicrobial activity.

    PubMed

    Ghosh, Somnath; Saraswathi, A; Indi, S S; Hoti, S L; Vasan, H N

    2012-06-01

    A novel in situ core@shell structure consisting of nanoparticles of Ag (Ag Nps) and AgI in agarose matrix (Ag@AgI/agarose) has been synthesized as a hybrid, in order to have an efficient antibacterial agent for repetitive usage with no toxicity. The synthesized core@shell structure is very well characterized by XRD, UV-visible, photoluminescence, and TEM. A detailed antibacterial studies including repetitive cycles are carried out on Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) bacteria in saline water, both in dark and on exposure to visible light. The hybrid could be recycled for the antibacterial activity and is nontoxic toward human cervical cancer cells (HeLa cells). The water insoluble Ag@AgI in agarose matrix forms a good coating on quartz, having good mechanical strength. EPR and TEM studies are carried out on the Ag@AgI/agarose and the bacteria, respectively, to elucidate a possible mechanism for killing of the bacteria. PMID:22582868

  5. No Evidence of Viral Transmission following Long-Term Implantation of Agarose Encapsulated Porcine Islets in Diabetic Dogs

    PubMed Central

    Gazda, Lawrence S.; Vinerean, Horatiu V.; Laramore, Melissa A.; Hall, Richard D.; Carraway, Joseph W.; Smith, Barry H.

    2014-01-01

    We have previously described the use of a double coated agarose-agarose porcine islet macrobead for the treatment of type I diabetes mellitus. In the current study, the long-term viral safety of macrobead implantation into pancreatectomized diabetic dogs treated with pravastatin (n = 3) was assessed while 2 dogs served as nonimplanted controls. A more gradual return to preimplant insulin requirements occurred after a 2nd implant procedure (days 148, 189, and >652) when compared to a first macrobead implantation (days 9, 21, and 21) in all macrobead implanted animals. In all three implanted dogs, porcine C-peptide was detected in the blood for at least 10 days following the first implant and for at least 26 days following the second implant. C-peptide was also present in the peritoneal fluid of all three implanted dogs at 6 months after 2nd implant and in 2 of 3 dogs at necropsy. Prescreening results of islet macrobeads and culture media prior to transplantation were negative for 13 viruses. No evidence of PERV or other viral transmission was found throughout the study. This study demonstrates that the long-term (2.4 years) implantation of agarose-agarose encapsulated porcine islets is a safe procedure in a large animal model of type I diabetes mellitus. PMID:24995342

  6. Nanoparticle size distributions measured by optical adaptive-deconvolution passivated-gel electrophoresis.

    PubMed

    Zhu, Xiaoming; Mason, Thomas G

    2014-12-01

    We image visible light scattered from dispersions of charged spherical nanoparticles propagating through a passivated agarose gel during electrophoresis. By analyzing one-dimensional light intensities along different lanes, we measure the mobility distributions of the nanoparticles and thereby infer their size distributions, which become time-independent after adequate propagation and separation have occurred. For a given large-pore passivated agarose gel, experiments using monodisperse, surfactant-free, sulfate-stabilized, polystyrene nanopheres establish the propagation distance as a function of time for a range of different sphere radii having known surface charges. As bands of monodisperse nanospheres propagate through the gel, the bands become smeared, developing asymmetric tails as some nanospheres experience additional delays compared to others of the same size. After background subtraction, these bands, including their tails, can be fit well using a modified log-normal distribution, yielding deconvolution parameters that vary with propagation distance and transit time. To demonstrate the approach for complex nanosphere dispersions, such as a multi-modal mixture or a broadly polydisperse nanoemulsion, we measure scattered light intensities as a function of propagation distance and time during gel-EP. Iterative deconvolution using a modified log-normal point-spread function, which changes shape according to propagation distance and time, directly yields unsmeared, high-resolution electrophoretic mobility distributions, from which detailed particle size distributions are inferred. PMID:25218049

  7. Surfactant free fractions of metallic and semiconducting single-walled carbon nanotubes via optimised gel chromatography

    SciTech Connect

    Lukaszczuk, Pawel; Ruemmeli, Mark H.; Knupfer, Martin; Kalenczuk, Ryszard J.; Borowiak-Palen, Ewa

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer The application of gel permeation chromatography technique in a field of SWCNT separation. Black-Right-Pointing-Pointer Non-commercial agarose gel used as a column filling. Black-Right-Pointing-Pointer Purification route is presented, quality and quantity estimation is shown. Black-Right-Pointing-Pointer Process is ready for high-scale separation of SWCNTs. -- Abstract: We report the procedure of sorting/purification of carbon nanotubes by electronic type using chromatographic column with sodium dodecylsulfate (SDS) and sodium deoxycholate (DOC) solutions as the eluents. The non-commercial agarose gel in different concentrations has been tested in the process. It was found that in optimal gel concentration the fractionation resulted in {approx}96.2% yield of semiconducting species. Importantly, to get surfactant-free fractions the post-separation purification procedure has been carried out. The UV-vis-NIR and Raman spectroscopy have been utilised for the samples analysis. High resolution transmission microscopy and thermogravimetric analysis allowed to study the sample morphology and purity, respectively.

  8. Orthopaedic Problems of the Mentally Retarded

    ERIC Educational Resources Information Center

    McSweeney, Anthony

    1972-01-01

    Problems encountered by orthopedic surgeons treating the mentally retarded are identified, and cooperation among pediatricians, psychiatrists, psychologists, social workers, physiotherapists, occupational therapists, and orthopedic surgeons is recommended. (GW)

  9. New resin gel for uranium determination by diffusive gradient in thin films technique.

    PubMed

    Gregusova, Michaela; Docekal, Bohumil

    2011-01-17

    A new resin gel based on Spheron-Oxin(®) chelating ion-exchanger with anchored 8-hydroxyquinoline functional groups was tested for application in diffusive gradient in thin film technique (DGT) for determination of uranium. Selectivity of uranium uptake from model carbonate loaded solutions of natural water was studied under laboratory conditions and compared with selectivity of the conventional Chelex 100 based resin gel. The affinity of Spheron-Oxin(®) functional groups enables determination of the overall uranium concentration in water containing carbonates up to the concentration level of 10(2) mg L(-1). The effect of uranium binding to the polyacrylamide (APA) and agarose diffusive gels (AGE) was also studied. Uranium is probably bound in both gels by a weak interaction with traces of acrylic acid groups in the structure of APA gel and with pyruvic and sulfonic acid groups in the AGE gel. These sorption effects can be eliminated to the negligible level by prolonged deployment of DGT probes or by disassembling probes after the 1-2 days post-sampling period that is sufficient for release of uranium from diffusive gel and its sorption in resin gel. PMID:21167996

  10. You and Your Retarded Child. A Manual for Parents of Retarded Children.

    ERIC Educational Resources Information Center

    Kirk, Samuel A.; And Others

    The book offers advice to parents of retarded children in recognizing and facing inherent problems and provides insight into their own emotional needs and those of their child. Levels of retardation are described and assistance given to aid parents in determining how retarded their child is and whether to send the child to a residential school or…

  11. Intumescent Coatings as Fire Retardants

    NASA Technical Reports Server (NTRS)

    Parker, J. A.; Fohlen, G. M.; Sawko, P. M.; Fish, R. H.

    1970-01-01

    The development of fire-retardant coatings to protect surfaces which may be exposed to fire or extreme heat is a subject of intense interest to many industries. A fire-retardant paint has been developed which represents a new chemical approach for preparing intumescent coatings, and potentially, is very important to fire-prevention authorities. The requirements for a superior coating include ease of application, suitability to a wide variety of surfaces and finishes, and stability over an extended period of time within a broad range of ambient temperature and humidity conditions. These innovative coatings, when activated by the heat of a fire, react to form a thick, low-density, polymeric coating or char layer. Water vapor and sulphur dioxide are released during the intumescent reaction. Two fire-protection mechanisms thus become available: (1) the char layer retards the flow of heat, due to the extremely low thermal conductivity; and (2) water vapor and sulfur dioxide are released, providing fire quenching properties. Still another mechanism functions in cases where the char, by virtue of its high oxidation resistance and low thermal conductivity, reaches a sufficiently high temperature to re-radiate much of the incident heat load. The coatings consist of dispersions of selective salts of a nitro-amino-arornatic compound. Specifically, para-nitroaniline bisulfate and the ammonium salt of para-nitroaniline-ortho sulphuric acid (2-amino-5-nitrobenzenesulphuric acid) are used. Suitable vehicles are cellulose nitrate of lacquer grade, a nitrite-phenolic modified rubber, or epoxy-polysulfide copolymer. Three separate formulations have been developed. A solvent is usually employed, such as methylethyl ketone, butyl acetate, or toluene, which renders the coatings suitably thin and which evaporates after the coatings are applied. Generally, the intumescent material is treated as insoluble in the vehicle, and is ground and dispersed in the vehicle and solvent like an

  12. Epidemiological issues in mental retardation.

    PubMed

    Fryers, T

    1987-12-01

    The basic epidemiological issues have not changed fundamentally in 30 years but emphases are different. Clarity of concept and definition is essential; we need several definitions for different purposes, and should distinguish global criteria defining groups in some way specifically 'retarded' and partial criteria defining groups not exclusive to retardation. Of global definitions, we can distinguish Intellectual Impairment based on IQ, Learning Disability based on educational criteria, and Mental Handicap or Retardation based on service or administrative criteria. The first and second may be co-terminous for children. The first and third are usually co-terminous below a certain IQ level, conventionally 50, as SII and SMH/R. This is not so for higher ability groups: MII and MMR are conceived and defined differently, and suit different research purposes. There may be much unknown need because there have been so few studies of total IQ defined groups above 50. Although organic and psychological factors are very important, the study of MMR needs to recognize its primarily social nature, reflecting determinants of selection into MMR status in legal, organizational and professional structures, activities and attitudes characteristic of particular communities and cultures. If the primary focus is on aetiological factors, natural history, and preventive possibilities, study group should be aetiologically defined and preferably not limited to MR. The same applies to specific impairments, disabilities, diseases, behaviours and disadvantages. The services are also susceptible to epidemiological approaches, descriptive, analytic, interventionist and evaluative, but little is yet available on agency structure and function, professional activities, attitudes and training, legal contexts, and financial constraints. Rigorous outcome studies would greatly benefit rapidly developing services. We know quite a lot about the distribution and associations of SII/SMR, though more is

  13. Preparation and characterization of agarose-nickel nanoporous composite particles customized for liquid expanded bed adsorption.

    PubMed

    Asghari, F; Jahanshahi, M; Ghoreyshi, A A

    2012-06-15

    Agarose-nickel nanoporous composite matrices with a series of densities, named Ag-Ni, were prepared herein for expanded bed adsorption of nanobioproduct/bioproduct by a water-in-oil emulsification method. The optical microscope (OM), scanning electronic microscope (SEM) and particle size analyzer (PSA) were utilized in order to characterize the structure and morphology of the agarose-nickel composite. The results indicated that the matrices prepared had a spherical appearance, appropriate wet density of 1.73-2.56 g/ml, water content of 32.2-58.5% and porosity of 79.4-96.37% and pore size of about 100-150 nm. All the Ag-Ni beads follow logarithmic normal size distribution with the range of 60-230 μm and average diameter of 133.68-148.4 μm. One of the useful properties of the Ag-Ni particles is the high wet density up to 2.56 g/ml, which shows a potential for the operation in an expanded bed at high flow rate. The impact of nickel powder addition on the physical and hydrodynamic properties was also investigated. In addition, the fluidization behavior of the Ag-Ni particles under various conditions was characterized by the measurement of bed expansion and axial dispersion coefficients for the liquid phase when operated in a standard fluidized bed contactor. It was observed that the expansion factors were decreased with the increasing matrix density under the same velocity. The bed expansion and fluid velocity were correlated with Richardson-Zaki equation for all particles prepared and the correlation parameters (the terminal settling velocity U(t) and expansion index n) were investigated. Using measurements of residence time distributions, hydrodynamic properties in the expanded beds were investigated and were compared with reported matrices in other literatures. In addition, the impact of the flow velocity, bed expansion degree and density of adsorbent on hydrodynamic properties in the expanded beds were investigated. The results indicated that the expansion factor

  14. Identifying Depression in Students with Mental Retardation.

    ERIC Educational Resources Information Center

    Stough, Laura M.; Baker, Lynn

    1999-01-01

    Offers guidelines to teachers for identifying depression in students with mental retardation. Discusses prevalence and symptoms of depression, causes of depression, difficulty of diagnosis in students with mental retardation, detecting symptoms in the classroom, treatment of depression, and psychological services. Inserts list ideas for helping…

  15. Teaching Language Arts to Mentally Retarded Children.

    ERIC Educational Resources Information Center

    Thomas, Janet K.

    Suggestions are made for teaching language arts to mentally retarded children. The nature of language arts, the effect of mental retardation on the learning of language arts, and the need for home-school cooperation are treated. Also described are language arts areas, the school program, methods of beginning instruction, speech training,…

  16. Arm Tremor, Tardive Dyskinesia, and Mental Retardation.

    ERIC Educational Resources Information Center

    van Emmerik, R. E. A.; And Others

    1993-01-01

    The arm tremor of adults (n=32) diagnosed as having mental retardation and/or tardive dyskinesia was examined through an analysis of the acceleration properties of several arm postures. The degree of arm acceleration was increased in all subjects compared to a control group without mental retardation. Effects of neuroleptic medication were noted.…

  17. Innovations in Vocational Rehabilitation and Mental Retardation.

    ERIC Educational Resources Information Center

    Ayers, George E., Ed.

    Conference proceedings of the Vocational Rehabilitation Subdivision Meetings held at the American Association on Mental Deficiency contain discussions of innovative aspects of vocational rehabilitation and mental retardation. In the area of training rehabilitation counselors, George Baroff describes the Mental Retardation Training Institute in…

  18. Political Philosophy and the Mentally Retarded.

    ERIC Educational Resources Information Center

    Stanovich, Keith E.

    The effects of Social Darwinism, eugenics, and contemporary political conservatism on the status of advocacy efforts for the mentally retarded are reviewed. Provided are historical sketches of Social Darwinism, which viewed the retarded as members of an inferior race, and eugenics, which argued for sterilization of the "genetically unfit". The…

  19. Retarded Children of the Poor: A Casebook.

    ERIC Educational Resources Information Center

    Kirkland, Majorie H.

    Written for welfare and social workers, the publication concerns families which have problems of retardation, usually mild or borderline, and which are heavily represented on welfare rolls. A brief discussion of retardation and family and child welfare services is followed by a list of suggested readings dealing with social and child welfare…

  20. Assertiveness Training and the Mentally Retarded.

    ERIC Educational Resources Information Center

    Granat, Jay P.

    1978-01-01

    This article reviews some of the basic principles of assertiveness training and explains the application of this treatment to the habilitation of mentally retarded adults. It presents qualitative data regarding the value of assertiveness training in a counseling group of mentally retarded persons and proposes several guidelines for counselors.…

  1. Body Awareness in Children with Mental Retardation

    ERIC Educational Resources Information Center

    Simons, Johan; Dedroog, Inge

    2009-01-01

    The body awareness of 124 toddlers with mental retardation and of 124 children developing normally matched to them on age and gender was examined. Twenty-nine of the children with mental retardation were diagnosed as Down syndrome (DS). The "Pointing and Naming" Test of Berges and Lezine [Berges, J., & Lezine, I. (1978). "Test d'imitation de…

  2. Mental Retardation: Update 2002. ERIC Digest.

    ERIC Educational Resources Information Center

    Hourcade, Jack

    This digest provides an overview of mental retardation in children and adults. It begins by discussing the definition of mental retardation and the three components that are required for an accurate diagnosis: an IQ score of approximately 70 or below, a determination of deficits in adaptive behavior, and origins of the disability prior to age 18.…

  3. UNDERSTANDING AND HELPING THE RETARDED READER.

    ERIC Educational Resources Information Center

    STRANG, RUTH, ED.

    THE PROCEEDINGS OF A 1962 STATEWIDE ARIZONA CONFERENCE ON READING DEVELOPMENT AND READING DIFFICULTIES INCLUDE 15 PAPERS. ARTICLES ON THE ABLE RETARDED READER ARE "UNDERSTANDING THE ABLE RETARDED READER" BY HELEN M. ROBINSON, AND "CLASSROOM PROCEDURES" BY ROSEMARY YOAKUM. PAPERS ON EMOTIONALLY DISTURBED CHILDREN ARE "IDENTIFICATION OF EMOTIONAL…

  4. Residential Facilities for the Mentally Retarded.

    ERIC Educational Resources Information Center

    Baumeister, Alfred A., Ed.; Butterfield, Earl, Ed.

    The handbook on residential institutions, for professionals and students in the field of mental retardation, attempts to interpret the institution as a part of the culture which it serves, avoiding emotional responses but suggesting formulas for change. Characteristics of contemporary institutions for the mentally retarded are examined and…

  5. Mental Retardation's Two Cultures of Behavioral Research.

    ERIC Educational Resources Information Center

    Hodapp, Robert M.; Dykens, Elisabeth M.

    1994-01-01

    This survey of nine journals identified two distinct cultures in mental retardation research: classification by level of retardation (usually by psychologists and special educators) or etiology (usually by geneticists and psychiatric researchers). The paper discusses varied effects that genetic etiology may have on behavior, issues in reconciling…

  6. Flame retardant cotton based highloft nonwovens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flame retardancy has been a serious bottleneck to develop cotton blended very high specific volume bulky High loft fabrics. Alternately, newer approach to produce flame retardant cotton blended High loft fabrics must be employed that retain soft feel characteristics desirable of furnishings. Hence, ...

  7. Teaching Physical Education to Mentally Retarded Children.

    ERIC Educational Resources Information Center

    Davis, Patricia A.

    Methods for teaching physical education activities and skills to mentally retarded children are presented. General objectives are listed and the physical education program is outlined. Hints are offered for teaching the retarded child; and basic skills and rhythms are described. The following are then described; rhythm games, a volleyball unit and…

  8. A Case of Pseudo-Retardation.

    ERIC Educational Resources Information Center

    Stott, D. H.

    Review of a case study of a 4-year-old girl who assumed the role of a retardate reveals that the girl probably suffered multiple congenital impairments of a minor character that affected the central nervous system and the structures governing social behavior and maturation. The stated basis for pseudo-retardation is the person's ability to…

  9. Poverty and Mental Retardation: A Causal Relationship.

    ERIC Educational Resources Information Center

    Hurley, Rodger L.

    The incidence of mental retardation among the poor and the reasons for such high prevalence are the focus of the text which is based largely on the state of New Jersey. Mental retardation is viewed as a social pathology which thrives in the ghetto; the effects of poverty and racial prejudice are explored as are the assessment of intelligence and…

  10. Counseling the Mentally Retarded: A Psychoeducational Perspective.

    ERIC Educational Resources Information Center

    Spragg, Paul A.

    The paper suggests that a cognitive or psychoeducational perspective is valuable in counseling mentally retarded individuals. Psychoeducational considerations in pretreatment assessment, with an emphasis on process rather than product, are noted; and it is explained that counseling of mentally retarded persons can be enhanced through the use of…

  11. Noncitizen: Plight of the Mentally Retarded

    ERIC Educational Resources Information Center

    Skarnulis, Ed

    1974-01-01

    Mentally retarded citizens have been denied their human and civil rights, not only by the public, but by professionals--including social workers. The author claims that most programs for the mentally retarded are, at best, dehumanizing. Professionals have an ethical obligation to refuse to refer children to such programs. (Author)

  12. Computational Errors of Mentally Retarded Students.

    ERIC Educational Resources Information Center

    Janke, Robert W.

    1980-01-01

    Examined computational errors made by educable mentally retarded students on the arithmetic subtest of the Wide Range Achievement Test. Retarded students had a lower percent of grouping and inappropriate inversion errors and a higher percent of incorrect operation errors than regular students had in Engelhardt's study. (Author)

  13. Care Of The Mentally Retarded

    PubMed Central

    Jacobs, J.

    1979-01-01

    Mental retardation is a clinical syndrome, not an intellectual defect or brain disease per se. As such, physicians should not participate in the downgrading labelling of moron, idiot and imbecile. Such labelled people are difficult to relate to and this results in the concept of 'nil expectations' in which the whole of society participates. Maladaptation in this syndrome is more related to poor environmental input than to basic organic defect, and is a family problem. The family doctor is in an ideal situation to help the family handle the problems of anger, shame, guilt, rejection. If aware of his own feelings, he should also be the coordinator of the physical needs of the child and the alternatives available for maximal input. Imagesp1344-a PMID:21297810

  14. Toward a positive psychology of mental retardation.

    PubMed

    Dykens, Elisabeth M

    2006-04-01

    Researchers and practitioners alike have long focused on the external life conditions, adaptive behavior, and inclusion of persons with mental retardation. Using breakthroughs in positive psychology, this article proposes a new research agenda focused on the positive, internal states of those with mental retardation. It shows how major movements in the mental retardation field--quality of life, dual diagnosis, personality motivation, and families--have succeeded in some arenas but failed to address happiness and well-being. Examples of happiness--of positive emotions, flow, strengths, and virtues--are offered in people with genetic causes of mental retardation. Complexities related to etiology, measurement, flow, and a meaningful life are described, as is the vital role that mental retardation can play in the emerging science of positive psychology. PMID:16719637

  15. IPN hydrogel nanocomposites based on agarose and ZnO with antifouling and bactericidal properties.

    PubMed

    Wang, Jingjing; Hu, Hongkai; Yang, Zhonglin; Wei, Jun; Li, Juan

    2016-04-01

    Nanocomposite hydrogels with interpenetrating polymer network (IPN) structure based on poly(ethylene glycol) methyl ether methacrylate modified ZnO (ZnO-PEGMA) and 4-azidobenzoic agarose (AG-N3) were prepared by a one-pot strategy under UV irradiation. The hydrogels exhibited a highly macroporous spongelike structure, and the pore size decreased with the increase of the ZnO-PEGMA content. Due to the entanglement and favorable interactions between the two crosslinked networks, the IPN hydrogels exhibited excellent mechanical strength and light transmittance. The maximum compressive and tensile strengths of the IPN hydrogels reached 24.8 and 1.98 MPa respectively. The transparent IPN hydrogels transmitted more than 85% of visible light at all wavelengths (400-800 nm). The IPN hydrogels exhibited anti-adhesive property towards Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), and the bactericidal activity increased with the ZnO-PEGMA content. The incorporation of ZnO-PEGMA did not reduce the biocompatibility of the IPN hydrogels and all the IPN nanocomposites showed negligible cytotoxicity. The present study not only provided a facile method for preparing hydrogel nanocomposites with IPN structure but also developed a new hydrogel material which might be an excellent candidate for wound dressings. PMID:26838864

  16. Achondrogenesis type IB (Fraccaro): study of collagen in the tissue and in chondrocytes cultured in agarose.

    PubMed

    Freisinger, P; Stanescu, V; Jacob, B; Cohen-Solal, L; Maroteaux, P; Bonaventure, J

    1994-02-15

    A lethal chondrodysplasia characterized by extreme micromelia was diagnosed by ultrasound examination in two sibs whose nonconsanguineous parents were healthy. Radiographic and histopathologic data indicated that the two foetuses (18 and 21 weeks old) had achondrogenesis type IB (Fraccaro). Quantitation of total collagen extractable from dried cartilage samples demonstrated a 50% decrease when compared to an age-related control. This decrease was essentially related to type II collagen. Nevertheless, the alpha chains and the CB peptides of type II collagen had a normal electrophoretic mobility. A significant amount of collagen type I was also detected. The electrophoretic pattern of collagens type IX and XI did not differ significantly from control sample. The extracellular matrix elaborated by patient chondrocytes cultured in agarose for 10-12 days, contained less collagen type II than normal cells. Labelling with 14C-proline of cultured cells showed the presence of procollagen and type II collagen chains with a normal electrophoretic mobility, but an alpha 2(I) chain was detectable in the patient material, indicating the presence of collagen type I which supported the tissue findings. The significance of the type II collagen reduction in the patient's cartilage is unclear but it is unlikely to be the primary defect in achondrogenesis type I. PMID:8160740

  17. Stabilization of Candida antarctica Lipase B (CALB) Immobilized on Octyl Agarose by Treatment with Polyethyleneimine (PEI).

    PubMed

    Peirce, Sara; Tacias-Pascacio, Veymar G; Russo, Maria Elena; Marzocchella, Antonio; Virgen-Ortíz, José J; Fernandez-Lafuente, Roberto

    2016-01-01

    Lipase B from Candida antarctica (CALB) was immobilized on octyl agarose (OC) and physically modified with polyethyleneimine (PEI) in order to confer a strong ion exchange character to the enzyme and thus enable the immobilization of other enzymes on its surface. The enzyme activity was fully maintained during the coating and the thermal stability was marginally improved. The enzyme release from the support by incubation in the non-ionic detergent Triton X-100 was more difficult after the PEI-coating, suggesting that some intermolecular physical crosslinking had occurred, making this desorption more difficult. Thermal stability was marginally improved, but the stability of the OCCALB-PEI was significantly better than that of OCCALB during inactivation in mixtures of aqueous buffer and organic cosolvents. SDS-PAGE analysis of the inactivated biocatalyst showed the OCCALB released some enzyme to the medium during inactivation, and this was partially prevented by coating with PEI. This effect was obtained without preventing the possibility of reuse of the support by incubation in 2% ionic detergents. That way, this modified CALB not only has a strong anion exchange nature, while maintaining the activity, but it also shows improved stability under diverse reaction conditions without affecting the reversibility of the immobilization. PMID:27338317

  18. Uranium (VI) recovery from aqueous medium using novel floating macroporous alginate-agarose-magnetite cryobeads.

    PubMed

    Tripathi, Anuj; Melo, Jose Savio; D'Souza, Stanislaus Francis

    2013-02-15

    This study presents a novel development of a floating polymeric-magnetite cryobead for the recovery of hexavalent uranium from the aqueous sub-surfaces. The alginate-agarose-magnetite cryobeads were synthesized by the process of cryotropic-gelation at subzero-temperature. The physico-chemical properties of cryobeads showed high surface area and high interconnected porosity (≈ 90%). Low density of these cryobeads explains their floating property in the aqueous medium. The rheological analysis of cryobeads showed its stability and increased stiffness after uranium adsorption. The presence of magnetite nanoparticles in the porous cryobeads facilitates the recovery of these beads by applying an external magnetic field. Maximum uranium adsorption (97 ± 2%) was observed in the pH range of 4.5-5.5. The thermodynamic parameters suggest passive endothermic adsorption behaviour. HCl was found to be an efficient eluent for the uranium desorption. Five repeated cycles for the desorption of uranium from biosorbent showed 69 ± 3% of uranium recovery. These results suggest stability of these novel floating magnetite-cryobeads under environmental conditions with potential for the recovery of uranium from contaminated aqueous subsurfaces. PMID:23280054

  19. Antifouling coatings based on covalently cross-linked agarose film via thermal azide-alkyne cycloaddition.

    PubMed

    Xu, Li Qun; Pranantyo, Dicky; Neoh, Koon-Gee; Kang, En-Tang; Teo, Serena Lay-Ming; Fu, Guo Dong

    2016-05-01

    Coatings based on thin films of agarose-poly(ethylene glycol) (Agr-PEG) cross-linked systems are developed as environmentally-friendly and fouling-resistant marine coatings. The Agr-PEG cross-linked systems were prepared via thermal azide-alkyne cycloaddition (AAC) using azido-functionalized Agr (AgrAz) and activated alkynyl-containing poly(2-propiolamidoethyl methacrylate-co-poly(ethylene glycol)methyl ether methacrylate) P(PEMA-co-PEGMEMA) random copolymers as the precursors. The Agr-PEG cross-linked systems were further deposited onto a SS surface, pre-functionalized with an alkynyl-containing biomimetic anchor, dopamine propiolamide, to form a thin film after thermal treatment. The thin film-coated SS surfaces can effectively reduce the adhesion of marine algae and the settlement of barnacle cyprids. Upon covalent cross-linking, the covalently cross-linked Agr-PEG films coated SS surfaces exhibit good stability in flowing artificial seawater, and enhanced resistance to the settlement of barnacle cyprids, in comparison to that of the surfaces coated with physically cross-linked AgrAz films. PMID:26836479

  20. Agarose Microchambers for Long-term Calcium Imaging of Caenorhabditis elegans.

    PubMed

    Turek, Michal; Besseling, Judith; Bringmann, Henrik

    2015-01-01

    Behavior is controlled by the nervous system. Calcium imaging is a straightforward method in the transparent nematode Caenorhabditis elegans to measure the activity of neurons during various behaviors. To correlate neural activity with behavior, the animal should not be immobilized but should be able to move. Many behavioral changes occur during long time scales and require recording over many hours of behavior. This also makes it necessary to culture the worms in the presence of food. How can worms be cultured and their neural activity imaged over long time scales? Agarose Microchamber Imaging (AMI) was previously developed to culture and observe small larvae and has now been adapted to study all life stages from early L1 until the adult stage of C. elegans. AMI can be performed on various life stages of C. elegans. Long-term calcium imaging is achieved without immobilizing the animals by using short externally triggered exposures combined with an electron multiplying charge-coupled device (EMCCD) camera recording. Zooming out or scanning can scale up this method to image up to 40 worms in parallel. Thus, a method is described to image behavior and neural activity over long time scales in all life stages of C. elegans. PMID:26132740

  1. Agarose Microchambers for Long-term Calcium Imaging of Caenorhabditis elegans

    PubMed Central

    Turek, Michal; Besseling, Judith; Bringmann, Henrik

    2015-01-01

    Behavior is controlled by the nervous system. Calcium imaging is a straightforward method in the transparent nematode Caenorhabditis elegans to measure the activity of neurons during various behaviors. To correlate neural activity with behavior, the animal should not be immobilized but should be able to move. Many behavioral changes occur during long time scales and require recording over many hours of behavior. This also makes it necessary to culture the worms in the presence of food. How can worms be cultured and their neural activity imaged over long time scales? Agarose Microchamber Imaging (AMI) was previously developed to culture and observe small larvae and has now been adapted to study all life stages from early L1 until the adult stage of C. elegans. AMI can be performed on various life stages of C. elegans. Long-term calcium imaging is achieved without immobilizing the animals by using short externally triggered exposures combined with an electron multiplying charge-coupled device (EMCCD) camera recording. Zooming out or scanning can scale up this method to image up to 40 worms in parallel. Thus, a method is described to image behavior and neural activity over long time scales in all life stages of C. elegans. PMID:26132740

  2. 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.

  3. Modeling the Dynamics of Gel Electrophorresis in the High School Classroom

    NASA Astrophysics Data System (ADS)

    Saucedo, Skyler R.

    2013-01-01

    Gel electrophoresis, used by geneticists and forensic experts alike, is an immensely popular technique that utilizes an electric field to separate molecules and proteins by size and charge. At the microscopic level, a dye or complex protein like DNA is passed through agarose, a gelatinous three-dimensional matrix of pores and nano-sized tunnels. When forced through a maze of holes, the molecule unravels, forming a long chain, slithering through the field of pores in a process colloquially coined "reputation." As a result, the smaller molecules travel farther through the gel when compared to molecules of larger molecular weight. This highly effective "molecular sieve" provides consistent data and allows scientists to compare similar sequences of DNA base pairs in a routine fashion.2 When performed at the high school level, gel electrophoresis provides students the opportunity to learn about a contemporary lab technique of great scientific relevance. Doing real science certainly excites students and motivates them to learn more.

  4. 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.

  5. Separation of galactose, 5-hydroxymethylfurfural and levulinic acid in acid hydrolysate of agarose by nanofiltration and electrodialysis.

    PubMed

    Kim, Jae Hyung; Na, Jeong-Geol; Yang, Ji-Won; Chang, Yong Keun

    2013-07-01

    A two-stage membrane process for the separation of galactose, 5-hydroxymethylfurfural (5-HMF) and levulinic acid (LA) has been proposed. The first step of nanofiltration (NF) is to remove 5-HMF and LA from galactose solution obtained by the hydrolysis of agarose, the main component of red algal galactan for the reduction of its microbial toxicity. 5-HMF and LA are inhibitory to fermentation but at the same time useful compounds themselves with many applications. The second step of electrodialysis (ED) is to separate 5-HMF and LA in the permeate from NF. More than 91% of 5-HMF and up to 62% of LA could be removed from agarose hydrolysate, while galactose was almost completely retained by NF. Further removal of LA was expected to be possible with no loss of galactose by operating the NF process in a diafiltration mode. 5-HMF and LA could be effectively separated from each other by ED. PMID:23672940

  6. Single-Cell-Arrayed Agarose Chip for in Situ Analysis of Cytotoxicity and Genotoxicity of DNA Cross-Linking Agents.

    PubMed

    Li, Lili; Wang, Weixing; Ding, Mingyu; Luo, Guoan; Liang, Qionglin

    2016-07-01

    Development of approach or device to allow continuous multiple measurements, such as integrating cytotoxic and genotoxic analysis, is quite appealing for study of the drug's activity and mechanism of action or resistance. In this study, a single-cell-arrayed agarose chip system was developed to combine cell cultivation with subsequent in situ analysis of cytotoxicity and genotoxicity of the chemotherapeutic agent. The modified alkaline comet assay coupled with the Live/Dead assay was used to monitor the interstrand cross-links (ICLs) formation and the cytotoxic effects in different glioma cell lines. In addition, the ICL-induced double strand breaks (DSBs) was measured on the chip to reflect the level of ICLs indirectly. Compared with the traditional methods, the microarray agarose device offers higher throughput, reproducibility, and robustness, exhibiting good potential for high-content drug screening. PMID:27269449

  7. Natural poly-histidine affinity tag for purification of recombinant proteins on cobalt(II)-carboxymethylaspartate crosslinked agarose.

    PubMed

    Chaga, G; Bochkariov, D E; Jokhadze, G G; Hopp, J; Nelson, P

    1999-12-24

    A natural 19-amino-acid poly-histidine affinity tag was cloned at the N-terminus of three recombinant proteins. The vectors containing the DNA of the fusion proteins were used for transformation of Escherichia coli DH5alpha cells. Each protein was expressed, extracted and purified in one chromatographic step. The purification procedure for each protein can be accomplished in less than 1 h. A new type of immobilized metal ion affinity chromatography adsorbent--Co2+-carboxymethylaspartate agarose Superflow--was utilized at linear flow-rates as high as 5 cm/min. The final preparation of each protein is with purity greater than 95% as ascertained by sodium dodecyl sulfate-electrophoresis. Recovery for each purified protein was higher than 77% of the initial loaded amount as judged by biological activity. The operational capacity of Co2+-carboxymethylaspartate agarose for each protein was determined. PMID:10669292

  8. Preparation of a novel pH optical sensor using orange (II) based on agarose membrane as support.

    PubMed

    Heydari, Rouhollah; Hosseini, Mohammad; Amraei, Ahmadreza; Mohammadzadeh, Ali

    2016-04-01

    A novel and cost effective optical pH sensor was prepared using covalent immobilization of orange (II) indicator on the agarose membrane as solid support. The fabricated optical sensor was fixed into a sample holder of a spectrophotometer instrument for pH monitoring. Variables affecting sensor performance including pH of dye bonding to agarose membrane and dye concentration were optimized. The sensor responds to the pH changes in the range of 3.0-10.0 with a response time of 2.0 min and appropriate reproducibility (RSD ≤ 0.9%). No significant variation was observed on sensor response after increasing the ionic strength in the range of 0.0-0.5M of sodium chloride. Determination of pH using the proposed optical sensor is quick, simple, inexpensive, selective and sensitive in the pH range of 3.0-10.0. PMID:26838857

  9. Inhibition of colony formation in agarose of metastatic human breast carcinoma and melanoma cells by synthetic glycoamine analogs.

    PubMed

    Glinsky, G V; Mossine, V V; Price, J E; Bielenberg, D; Glinsky, V V; Ananthaswamy, H N; Feather, M S

    1996-05-01

    We studied the influence of 10 synthetic glycoamine analogs on colony formation in 0.3 and 0.9% agarose by metastatic human breast carcinoma (MDA-MB-435) and melanoma (TXM-13) cells. Nine synthetic analogs significantly inhibited the colony formation in 0.9% agarose of MDA-MB-435 human breast carcinoma cells; five compounds caused a 73-83% reduction of colony formation. Seven synthetic glycoamines caused a significant inhibition of colony formation in 0.9% agarose by TXM-13 melanoma cells with the inhibitory effect ranging from 71 to 87%. The 50% inhibition (I50) doses and relative activity rank of the compounds were similar for both breast carcinoma and melanoma cell lines. The murine B16 melanoma cell aggregation assay was employed to elucidate the potential mechanism(s) of the inhibitory activity of synthetic glycoamines. The relative activity ranks of the compounds based on the independently determined I50 doses for both cell aggregation and clonogenic growth assays were very similar for the four most active synthetic analogs and clearly indicated the importance of hydrophobic amino acid in mediating the bioactivity of synthetic glycoamines. In both experimental systems (clonogenic growth in agarose and cell aggregation assay) the leading compound was N-(1-deoxy-D-fructos-1-yl)-D-leucine (Fru-D-Leu) and the least active analog was N-(l-deoxy-D-fructos-1-yl)-glycine (Fru-Gly). These results show that synthetic glycoamines may act by competing for specific carbohydrate-lectin interactions, particularly those involving beta-galactoside-specific lectins expressed on metastatic cells. PMID:8674280

  10. 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

  11. Gel mobilities of linking-number topoisomers and their dependence on DNA helical repeat and elasticity

    PubMed Central

    Vetcher, Alexandre A.; McEwen, Abbye E.; Abujarour, Ramzey; Hanke, Andreas; Levene, Stephen D.

    2010-01-01

    Agarose-gel electrophoresis has been used for more than thirty years to characterize the linking-number (Lk) distribution of closed-circular DNA molecules. Although the physical basis of this technique remains poorly understood, the gel-electrophoretic behavior of covalently closed DNAs has been used to determine the local unwinding of DNA by proteins and small-molecule ligands, characterize supercoiling-dependent conformational transitions in duplex DNA, and to measure helical-repeat changes due to shifts in temperature and ionic strength. Those results have been analyzed by assuming that the absolute mobility of a particular topoisomer is mainly a function of the integral number of superhelical turns, and thus a slowly varying function of plasmid molecular weight. In examining the mobilities of Lk topoisomers for a series of plasmids that differ incrementally in size over more than one helical turn, we found that the size-dependent agarose-gel mobility of individual topoisomers with identical values of Lk (but different values of the excess linking number, ΔLk) vary dramatically over a duplex turn. Our results suggest that a simple semi-empirical relationship holds between the electrophoretic mobility of linking-number topoisomers and their average writhe in solution. PMID:20346570

  12. Postnatal Organic Causes of Mental Retardation

    PubMed Central

    Hinton, G. G.

    1962-01-01

    A study of 1137 retarded children from Western Ontario revealed 129 (11.3%) in whom retardation was first noted after a specific postnatal event. Eighty-three of these were boys. The most common cause of postnatal cerebral injury in this series was a syndrome of unknown etiology characterized by the sudden onset of fever, convulsions and coma which occurred in 45 patients. The nature of this syndrome is discussed and the necessity for early treatment emphasized. Other postnatal causes of retardation are classified according to frequency, as encephalitis, accidents, meningitis and a miscellaneous group consisting of epilepsy and tumours. PMID:13907577

  13. Biodegradation of brominated and organophosphorus flame retardants.

    PubMed

    Waaijers, Susanne L; Parsons, John R

    2016-04-01

    Brominated flame retardants account for about 21% of the total production of flame retardants and many of these have been identified as persistent, bioaccumulative and toxic. Nevertheless, debromination of these chemicals under anaerobic conditions is well established, although this can increase their toxicity. Consequently, the production and use of these chemicals has been restricted and alternative products have been developed. Many of these are brominated compounds and share some of the disadvantages of the chemicals they are meant to replace. Therefore, other, nonbrominated, flame retardants such as organophosphorus compounds are also being used in increasing quantities, despite the fact that knowledge of their biodegradation and environmental fate is often lacking. PMID:26748263

  14. A polymeric flame retardant additive for rubbers

    SciTech Connect

    Ghosh, S.N.; Maiti, S.

    1993-12-31

    Synthesis of a polyphosphonate by the interfacial polymerization of bisphenol-A (BPA) and dichloro-phenyl phosphine oxide (DCPO) using cetyltrimethyl ammonium chloride (TMAC) as phase transfer catalyst (PTC) was reported. The polyphosphonate was characterized by elemental analysis, IR, TGA, DSC and 1H-NMR spectroscopy. The flame retardancy of the polymer was done by OI study. The polymer was used as a fire retardant additive to rubbers such as natural rubber (NR), styrene-butadiene rubber(SBR), nitrile rubber (NBR) and chloroprene rubber (CR). The efficiency of the fire retardant property of this additive was determined by LOI measurements of the various rubber samples.

  15. In vitro study of using calcium phosphate cement as immunoisolative device to enclose insulinoma/agarose microspheres as bioartificial pancreas.

    PubMed

    Kai-Chiang, Yang; Ching-Yao, Yang; Chang-Chin, Wu; Tzong-Fu, Kuo; Feng-Huei, Lin

    2007-12-15

    In this study, the feasibility of using calcium phosphate cement (CPC) as immunoisolative device to enclose insulinoma/agarose microspheres as bioartificial pancreas was evaluated. We fabricated a chamber by CPC and utilized X-ray diffraction, Scanning electron microscope and Mercury intrusion porosimetry to identify the characters of the CPC chamber. The nominal molecular weight cut-off and cytotoxicity of CPC chamber were also evaluated. An insulinoma cell line (RIN-m5F) was chosen as insulin source and encapsulated in agarose microspheres and then enclosed in preformed CPC chamber. Insulin secretion was analyzed by Enzyme-linked immunosorbant assay to evaluate the function of insulinoma enclosed in CPC chamber. Results showed that the CPC chamber was non-cytotoxicity to insulinoma and can block the penetration of molecules which molecular weight larger than 12.4 kDa. Insulinoma inside the CPC chamber can secrete insulin in stable level for 30 days. This study indicated that we may use CPC as immunoisolative material to enclose insulinoma/agarose microspheres as bioartificial pancreas. PMID:17514757

  16. Reversible covalent immobilization of Trametes villosa laccase onto thiolsulfinate-agarose: An insoluble biocatalyst with potential for decoloring recalcitrant dyes.

    PubMed

    Gioia, Larissa; Rodríguez-Couto, Susana; Menéndez, María Del Pilar; Manta, Carmen; Ovsejevi, Karen

    2015-01-01

    The development of a solid-phase biocatalyst based on the reversible covalent immobilization of laccase onto thiol-reactive supports (thiolsulfinate-agarose [TSI-agarose]) was performed. To achieve this goal, laccase-producing strains isolated from Eucalyptus globulus were screened and white rot fungus Trametes villosa was selected as the best strain for enzyme production. Reduction of disulfide bonds and introduction of "de novo" thiol groups in partially purified laccase were assessed to perform its reversible covalent immobilization onto thiol-reactive supports (TSI-agarose). Only the thiolation process dramatically improved the immobilization yield, from 0% for the native and reduced enzyme to 60% for the thiolated enzyme. Mild conditions for the immobilization process (pH 7.5 and 4°C) allowed the achievement of nearly 100% of coupling efficiency when low loads were applied. The kinetic parameters, pH, and thermal stabilities for the immobilized biocatalyst were similar to those for the native enzyme. After the first use and three consecutives reuses, the insoluble derivative kept more than 80% of its initial capacity for decolorizing Remazol Brilliant Blue R, showing its suitability for color removal from textile industrial effluents. The possibility of reusing the support was demonstrated by the reversibility of enzyme-support binding. PMID:25196324

  17. Hollow agarose microneedle with silver coating for intradermal surface-enhanced Raman measurements: a skin-mimicking phantom study

    NASA Astrophysics Data System (ADS)

    Yuen, Clement; Liu, Quan

    2015-06-01

    Human intradermal components contain important clinical information beneficial to the field of immunology and disease diagnosis. Although microneedles have shown great potential to act as probes to break the human skin barrier for the minimally invasive measurement of intradermal components, metal microneedles that include stainless steel could cause the following problems: (1) sharp waste production, and (2) contamination due to reuse of microneedles especially in developing regions. In this study, we fabricate agarose microneedles coated with a layer of silver (Ag) and demonstrate their use as a probe for the realization of intradermal surface-enhanced Raman scattering measurements in a set of skin-mimicking phantoms. The Ag-coated agarose microneedle quantifies a range of glucose concentrations from 5 to 150 mM inside the skin phantoms with a root-mean-square error of 5.1 mM within 10 s. The needle is found enlarged by 53.9% after another 6 min inside the phantom. The shape-changing capability of this agarose microneedle ensures that the reuse of these microneedles is impossible, thus avoiding sharp waste production and preventing needle contamination, which shows the great potential for safe and effective needle-based measurements.

  18. Combination of fibrin-agarose hydrogels and adipose-derived mesenchymal stem cells for peripheral nerve regeneration

    NASA Astrophysics Data System (ADS)

    Carriel, Víctor; Garrido-Gómez, Juan; Hernández-Cortés, Pedro; Garzón, Ingrid; García-García, Salomé; Sáez-Moreno, José Antonio; Sánchez-Quevedo, María del Carmen; Campos, Antonio; Alaminos, Miguel

    2013-04-01

    Objective. The objective was to study the effectiveness of a commercially available collagen conduit filled with fibrin-agarose hydrogels alone or with fibrin-agarose hydrogels containing autologous adipose-derived mesenchymal stem cells (ADMSCs) in a rat sciatic nerve injury model. Approach. A 10 mm gap was created in the sciatic nerve of 48 rats and repaired using saline-filled collagen conduits or collagen conduits filled with fibrin-agarose hydrogels alone (acellular conduits) or with hydrogels containing ADMSCs (ADMSC conduits). Nerve regeneration was assessed in clinical, electrophysiological and histological studies. Main results. Clinical and electrophysiological outcomes were more favorable with ADMSC conduits than with the acellular or saline conduits, evidencing a significant recovery of sensory and motor functions. Histological analysis showed that ADMSC conduits produce more effective nerve regeneration by Schwann cells, with higher remyelination and properly oriented axonal growth that reached the distal areas of the grafted conduits, and with intensely positive expressions of S100, neurofilament and laminin. Extracellular matrix was also more abundant and better organized around regenerated nerve tissues with ADMSC conduits than those with acellular or saline conduits. Significance. Clinical, electrophysiological and histological improvements obtained with tissue-engineered ADMSC conduits may contribute to enhancing axonal regeneration by Schwann cells.

  19. Public health implications of components of plastics manufacture. Flame retardants.

    PubMed Central

    Pearce, E M; Liepins, R

    1975-01-01

    The four processes involved in the flammability of materials are described and related to the various flame retardance mechanisms that may operate. Following this the four practical approaches used in improving flame retardance of materials are described. Each approach is illustrated with a number of typical examples of flame retardants or synthetic procedures used. This overview of flammability, flame retardance, and flame retardants used is followed by a more detailed examination of most of the plastics manufactured in the United States during 1973, their consumption patterns, and the primary types of flame retardants used in the flame retardance of the most used plastics. The main types of flame retardants are illustrated with a number of typical commercial examples. Statistical data on flame retardant market size, flame retardant growth in plastics, and price ranges of common flame retardants are presented. Images FIGURE 1. FIGURE 2. FIGURE 3. FIGURE 4. PMID:1175568

  20. Simian Virus 40 Deoxyribonucleic Acid Synthesis: Analysis by Gel Electrophoresis

    PubMed Central

    Tegtmeyer, Peter; Macasaet, Francisco

    1972-01-01

    An agarose-gel electrophoresis technique has been developed to study simian virus 40 deoxyribonucleic acid (DNA) synthesis. Superhelical DNA I, relaxed DNA II, and replicative intermediate (RI) molecules were clearly resolved from one another for analytical purposes. Moreover, the RI molecules could be identified as early or late forms on the basis of their electrophoretic migration in relation to that of DNA II. The technique has been utilized to study the kinetics of simian virus 40 DNA synthesis in pulse and in pulse-chase experiments. The average time required to complete the replication of prelabeled RI molecules and to convert them into DNA I was approximately 10 min under the experimental conditions employed. PMID:4343542

  1. Engineering Flame Retardant Biodegradable Nanocomposites

    NASA Astrophysics Data System (ADS)

    He, Shan; Yang, Kai; Guo, Yichen; Zhang, Linxi; Pack, Seongchan; Davis, Rachel; Lewin, Menahem; Ade, Harald; Korach, Chad; Kashiwagi, Takashi; Rafailovich, Miriam

    2013-03-01

    Cellulose-based PLA/PBAT polymer blends can potentially be a promising class of biodegradable nanocomposites. Adding cellulose fiber reinforcement can improve mechanical properties of biodegradable plastics, but homogeneously dispersing hydrophilic cellulose in the hydrophobic polymer matrix poses a significant challenge. We here show that resorcinol diphenyl phosphates (RDP) can be used to modify the surface energy, not only reducing phase separation between two polymer kinds but also allowing the cellulose particles and the Halloysite clay to be easily dispersed within polymer matrices to achieve synergy effect using melt blending. Here in this study we describe the use of cellulose fiber and Halloysite clay, coated with RDP surfactant, in producing the flame retardant polymer blends of PBAT(Ecoflex) and PLA which can pass the stringent UL-94 V0 test. We also utilized FTIR, SEM and AFM nanoindentation to elucidate the role RDP plays in improving the compatibility of biodegradable polymers, and to determine structure property of chars that resulted in composites that could have optimized mechanical and thermal properties. Supported by Garcia Polymer Center and NSF Foundation.

  2. 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

  3. High-Frequency Alternating-Crossed-Field Gel Electrophoresis WithNeutral or Slightly Charged Interpenetrating Networks to Improve DNASeparation

    SciTech Connect

    Boyd, B.; Prausnitz, J.; Blanch, H.

    1998-07-01

    Toward improving DNA separations, this work reports theeffects of high-frequency square-wave AC fields superimposedperpendicular to the direct current (DC) separation field on DNAmigration in both polyacrylamide-based interpenetrating networks (IPNs)and in agarose networks. Compared to standard polyacrylamide gels, IPNsallow the separation of larger DNA (9000 bp vs. 5000 bp at 5 V/cm). Innovel polyacrylamide-based IPNs, an alternating current (AC) field of 5Hz increased the maximum DNA size separable. This effect was extended tolarger DNA sizes with increasing electric-field strength up to andapparently beyond the power supply-limited maximum electric-fieldstrength of 48 V/cm. The orthogonal AC field also increased mobility.These two results combine to yield a reduction in separation time of upto a factor of 20 in novel polyacrylamide-based IPNs. When negativelycharged acrylic-acid groups were incorporated into the IPNs, the use ofthe AC field changed the DNA-network interaction, which altered the sizedependence of DNA mobility. In agarose gels, an AC field of 50 Hzincreased the size range separable; however, there was no increase in DNAmobility. There was no change in size dependence of mobility in an ACfield when the number of charged groups in the agarose network wasincreased. Based on results in the literature, possible mechanisms wereexamined for the effects of the AC field on DNA separation.

  4. Brominated Flame Retardants and Perfluorinated Chemicals

    EPA Science Inventory

    Brominated flame retardants (BFRs) and perfluorinated chemicals (PFCs) belong to a large class of chemicals known as organohalogens. It is believed that both BFRs and PFCs saved lives by reducing flammability of materials commonly used and bactericidal (biocidal) properties. Thes...

  5. Video Tape and the Mentally Retarded

    ERIC Educational Resources Information Center

    Weisbord, H. F.

    1972-01-01

    Three uses of video tape recordings with the mentally retarded; discussed briefly are staff training or teacher education, parental involvement in the child's education, and therapeutic uses by psychiatrists and psychologists. (CB)

  6. Job Enrichment and the Mentally Retarded Worker.

    ERIC Educational Resources Information Center

    Morris, Jerry L.; And Others

    1981-01-01

    The effect of job enrichment on the production rate of 14 mentally retarded adult workers was evaluated. Job enrichment led to increases in standard rates of production for high IQ Ss and lower rates for low IQ Ss. (Author)

  7. Sterilization of Persons with Mental Retardation.

    ERIC Educational Resources Information Center

    Elkins, Thomas E.; Andersen, H. Frank

    1992-01-01

    This article examines the historical, legal, and ethical concerns regarding sterilization for persons with mental retardation and offers guidelines to help counsel individuals with disabilities or their families regarding decision making about sterilization. (DB)

  8. Retarded Children at Camp with Normal Children

    ERIC Educational Resources Information Center

    Flax, Norman; Peters, Edward N.

    1969-01-01

    Statistical analysis of data from written forms and scales (designed to measure children's behavior in groups), observations, and interviews indicated that many educalble mentally retarded children can participate successfully in camp activities with normal children. (DR)

  9. Retardation Measurements of Infrared PVA Wave plate

    NASA Astrophysics Data System (ADS)

    Sun, Y.; Z, H.; W, D.; D, Y.; Z, Z.; S, J.

    The wave plate made of Polyvinyl Alcohol PVA plastic film has several advantages such as its lower cost and insensitivity to temperature and incidence angle so it has been used in the Solar Multi-Channel Telescope SMCT in China But the important parameter retardations of PVA wave plates in the near infrared wavelength have never been provided In this paper a convenient and high precise instrument to get the retardations of discrete wavelengths or a continuous function of wavelength in near infrared is developed In this method the retardations of wave plates have been determined through calculating the maximum and minimum of light intensity The instrument error has been shown Additionally we can get the continuous direction of wavelength retardations in the ultraviolet visible or infrared spectral in another way

  10. PCBs, PBBs and Brominated Flame Retardants

    EPA Science Inventory

    This chapter introduces selected organohalogen chemicals such as polychlorinated biphenyls (PCB5), polychiorinated biphenyls (PBBs), and brominated flame retardants (BFRs) with emphasis on the background, physicochemical properties, environmental levels, health effects and possib...

  11. Detrapping Particles in a Gel : A Numerical Study

    NASA Astrophysics Data System (ADS)

    Dubé, Antoine; Torres, Francis; Slater, Gary W.

    2009-03-01

    Pulsed fields are widely used in gel electrophoretic separations to increase resolution. For instance, Boyde & To [1] presented experimental results for the separation of spherical particles using pulsed fields. They first used alternating fields of fixed amplitudes (E±=±| E |) applied in the forward direction for a duration twice as long as in the backward direction. They then used field interruption in order to allow particles to thermally detrap. In both cases, they reported that using a pulsed field makes the particles migrate faster. We model the gel used in electrophoresis as a 2D system of obstacles on a lattice. We use a method that allows us to calculate the exact mean velocity of a particle for Monte-Carlo simulations to first reproduce the experimental results presented above. We then investigate different signals (e.g., telegraph signal) to determine the optimal conditions. Optimal conditions can be either higher velocities or larger velocity differences between particles. [4pt] [1] Pulsed-field acceleration: The electrophoretic behavior of large spherical particles in agarose gels, Electrophoresis, 1993.

  12. Anterior cervical hypertrichosis and mental retardation.

    PubMed

    Thienpont, Bernard; Vermeesch, Joris; Devriendt, Koen

    2006-07-01

    Anterior cervical hypertrichosis or hairy throat is a rare dysmorphic sign described in a total of 19 patients so far. The association with a number of additional features has been reported, including mental retardation. We report on another patient with this condition who also had moderate mental retardation, mildly dysmorphic facial features, obesity, hypermetropia and additional hair anomalies (low dorsal hair line on the neck, lumbosacral hypertrichosis). Karyotype and array comparative genomic hybridization analysis at 1 Mb resolution were normal. PMID:16760744

  13. 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

  14. 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

  15. Realidades Acerca de la Deficiencia Mental = Facts about Mental Retardation.

    ERIC Educational Resources Information Center

    Texas State Dept. of Mental Health and Mental Retardation, Austin.

    This document consists of two booklets, one in Spanish and one in English, both covering the same text: the characteristics of mentally retarded individuals, the prevalence of mentally retarded persons in Texas, causes of mental retardation, prevention possibilities, and services available to mentally retarded persons in Texas. A distinction is…

  16. Trends in Classification Usage in the Mental Retardation Literature.

    ERIC Educational Resources Information Center

    Taylor, Ronald L.; Kaufmann, Steve

    1991-01-01

    A total of 685 articles in "Mental Retardation,""American Journal of Mental Deficiency," and "American Journal on Mental Retardation" from 1980 through 1989 were examined. The mental retardation classification system developed by the American Association on Mental Retardation was used in over 50 percent of the articles, whereas the American…

  17. Novel application of PhastSystem polyacrylamide gel electrophoresis using restriction fragment length polymorphism--internal transcribed spacer patterns of individuals for molecular identification of entomopathogenic nematodes.

    PubMed

    Pamjav, H; Triga, D; Buzás, Z; Vellai, T; Lucskai, A; Adams, B; Reid, A P; Burnell, A; Griffin, C; Glazer, I; Klein, M G; Fodor, A

    1999-06-01

    différences! [editorial] [editorial]onomic way of identifying and assigning nematodes to taxons, which had already been determined either by comparative sequence analysis of nuclear rDNA internal transcribed spacer (ITS) region or by other methods of molecular or conventional taxonomy, is provided. Molecular identification of entomopathogenic nematodes (EPN) can be upgraded by basing it on PhastSystem polyacrylamide gel electrophoresis (PAGE) analysis of restriction fragment length polymorphism (RFLP) patterns of polymerase chain reaction (PCR)-amplified DNA derived from single nematodes of Steinernema or Heterorhabditis spp. Although analysis from single worms has previously been made on agarose gel, the resolution on PhastSystem PAGE gel is much higher. The DNA sequences selected for analysis were those constituting the internal transcribed spacer region between the 18S and 26S rDNA genes within the rRNA operon. RFLP analysis was carried out by gel electrophoresis on the PhastSystem (Pharmacia) as detailed elsewhere (Triga et al., Electrophoresis 1999, 20, 1272-1277. The downscaling from conventional agarose to PhastSystem gels resulted in pattern of DNA fragments differing from those obtained with agarose gel electrophoresis under conventional conditions by increasing the number of detected fragments. The approach supported previous species identifications and was able to identify several unclassified isolates, such as those from Hungary and Ireland, and provides a method for identification of previously unclassified strains. We confirmed that Heterorhabditis "Irish Type", represented by two strains of different geographical origin, comprise a species different from H. megidis. We also confirmed that strain IS5 belongs to the species H. indicus rather than to H. bacteriophora, as had been suggested previously. PMID:10380767

  18. Intrauterine radiation exposures and mental retardation

    SciTech Connect

    Miller, R.W.

    1988-08-01

    Small head size and mental retardation have been known as effects of intrauterine exposure to ionizing radiation since the 1920s. In the 1950s, studies of Japanese atomic-bomb survivors revealed that at 4-17 wk of gestation, the greater the dose, the smaller the brain (and head size), and that beginning at 0.5 Gy (50 rad) in Hiroshima, mental retardation increased in frequency with increasing dose. No other excess of birth defects was observed. Otake and Schull (1984) pointed out that the period of susceptibility to mental retardation coincided with that for proliferation and migration of neuronal elements from near the cerebral ventricles to the cortex. Mental retardation could be the result of interference with this process. Their analysis indicated that exposures at 8-15 wk to 0.01-0.02 Gy (1-2 rad) doubled the frequency of severe mental retardation. This estimate was based on small numbers of mentally retarded atomic-bomb survivors. Although nuclear accidents have occurred recently, new cases will hopefully be too rare to provide further information about the risk of mental retardation. It may be possible, however, to learn about lesser impairment. New psychometric tests may be helpful in detecting subtle deficits in intelligence or neurodevelopmental function. One such test is PEERAMID, which is being used in schools to identify learning disabilities due, for example, to deficits in attention, short- or long-term memory, or in sequencing information. This and other tests could be applied in evaluating survivors of intrauterine exposure to various doses of ionizing radiation. The results could change our understanding of the safety of low-dose exposures.

  19. Reactions to the Labels "Institutionalized" and "Mentally Retarded" by Retarded and Nonretarded Persons.

    ERIC Educational Resources Information Center

    Gibbons, Frederick X.; Gibbons, Barbara N.

    The effects of labels, "mentally retarded" and "institutionalized" on the evaluations and causal attributions of nonretarded persons, and on the social distance preferences of EMR persons, were assessed. In addition, each group was asked to predict the likelihood of a labeled (mentally retarded) or a nonlabeled target person achieving success at a…

  20. 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.

  1. 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 ...

  2. 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.

  3. X linked mental retardation: a clinical guide

    PubMed Central

    Raymond, F L

    2006-01-01

    Mental retardation is more common in males than females in the population, assumed to be due to mutations on the X chromosome. The prevalence of the 24 genes identified to date is low and less common than expansions in FMR1, which cause Fragile X syndrome. Systematic screening of all other X linked genes in X linked families with mental retardation is currently not feasible in a clinical setting. The phenotypes of genes causing syndromic and non‐syndromic mental retardation (NLGN3, NLGN4, RPS6KA3(RSK2), OPHN1, ATRX, SLC6A8, ARX, SYN1, AGTR2, MECP2, PQBP1, SMCX, and SLC16A2) are first discussed, as these may be the focus of more targeted mutation analysis. Secondly, the relative prevalence of genes causing only non‐syndromic mental retardation (IL1RAPL1, TM4SF2, ZNF41, FTSJ1, DLG3, FACL4, PAK3, ARHGEF6, FMR2, and GDI) is summarised. Thirdly, the problem of recurrence risk where a molecular genetics diagnosis has not been made and what proportion of the male excess of mental retardation is due to monogenic disorders of the X chromosome are discussed. PMID:16118346

  4. 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.

  5. 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

  6. 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.

  7. 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

  8. Genotoxicity effect, antioxidant and biomechanical correlation: experimental study of agarose-chitosan bone graft substitute in New Zealand white rabbit model.

    PubMed

    Jebahi, Samira; Ben Saleh, Ghada; Saoudi, Mongi; Besaleh, Salma; Oudadesse, Hassane; Mhadbi, Moufida; Rebai, Tarek; Keskes, Hassib; El Feki, Abdelfattah

    2014-08-01

    Bone loss associated with skeletal trauma or metabolic diseases often requires bone grafting. In such situations, a biomaterial is necessary for migrated cells to produce new tissue. In this study, agarose-chitosan was implanted in the femoral condyle of New Zealand White rabbits that were divided into three groups: Group I was used as control; Groups II and III were used as implanted tissue with agarose-chitosan and presenting empty defects, respectively. This study evaluated the agarose-chitosan biocompatibility by determining the in vivo genotoxicity, oxidative stress balance that correlated with the hardness mechanical property. Moreover, the histopathological and quantitative elements analyzed by using inductively coupled plasma optical emission spectrometry were determined. After 30 days of implantation, the in vivo analysis of genotoxicity showed that agarose-chitosan did not induce chromosome aberration or micronucleus damage. A significant decrease in thiobarbituric and acid-reactive substance was observed after agarose-chitosan implantation in the bone tissue. Superoxide dismutase, catalase and glutathione peroxidase were significantly enhanced in agarose-chitosan-treated group compared with that of control group. A negative correlation coefficient of the mechanical property with malonyldialdehyde level was detected (R = -0.998). The histological study exhibited a significantly increased angiogenesis and newly formed tissue. No presence of inflammatory process, necrotic or fibrous tissue was detected. Major and trace elements such as Ca, P, Zn, Mg and Fe were increased significantly in the newly formed bone. These findings show that agarose-chitosan biomaterial implantation might be effective for treating trauma and bone regeneration. PMID:25205747

  9. Eco-friendly functionalized superhydrophobic recycled paper with enhanced flame-retardancy.

    PubMed

    Si, Yifan; Guo, Zhiguang

    2016-09-01

    Recycled paper with superhydrophobicity and flame-retardancy has been demonstrated here due to the synergistic action of dopamine-silica trimethylsilyl modified gel powder and stearic acid modified Mg(OH)2. This multifunctional recycled paper displays great self-cleaning and anti-fouling ability and can be used for oil-water separation. Surprisingly, the absorbed organic can be reused as fuel via simple combustion method for multiple cycles. This work will not only expand the usable range of paper but also ease the energy and environment crisis. PMID:27244592

  10. Dataset of gene cloning and gel filtration chromatography of R-est6.

    PubMed

    Soni, Surabhi; Odaneth, Annamma A; Lali, Arvind M; Chandrayan, Sanjeev K

    2016-06-01

    The data presented in this article are connected to the research article entitled "Expression, purification and biochemical characterization of a family 6 carboxylesterase from Methylococcus capsulatus (bath)" (Soni et al., 2016 [1]). The family 6 carboxylesterases are the smallest and display broad substrate specificity. The 1 kb gene encoding, a family 6 carboxylesterase - R-est6, was amplified from the genome of M. capsulatus (bath strain), and showed in the agarose gel. The corresponding purified protein, after overexpression in Escherichia coli, was biochemically studied in the research article (Soni et al., 2016 [1]). R-est6 has hydrophobic patches on the surface so, it is expected to show oligimeric forms. Here, we have confirmed the presence of oligomers by gel filtration chromatography data and the proteins belonging to the different peaks are shown on a SDS-PAGE. PMID:27222859

  11. The influence of ionic strength on DNA diffusion in gel networks

    NASA Astrophysics Data System (ADS)

    Fu, Yuanxi; Jee, Ah-Young; Kim, Hyeong-Ju; Granick, Steve

    Cations are known to reduce the rigidity of the DNA molecules by screening the negative charge along the sugar phosphate backbone. This was established by optical tweezer pulling experiment of immobilized DNA strands. However, little is known regarding the influence of ions on the motion of DNA molecules as they thread through network meshes. We imaged in real time the Brownian diffusion of fluorescent labeled lambda-DNA in an agarose gel network in the presence of salt with monovalent or multivalent cations. Each movie was analyzed using home-written program to yield a trajectory of center of the mass and the accompanying history of the shape fluctuations. One preliminary finding is that ionic strength has a profound influence on the slope of the trace of mean square displacement (MSD) versus time. The influence of ionic strength on DNA diffusion in gel networks.

  12. High performance gel imaging with a commercial single lens reflex camera

    NASA Astrophysics Data System (ADS)

    Slobodan, J.; Corbett, R.; Wye, N.; Schein, J. E.; Marra, M. A.; Coope, R. J. N.

    2011-03-01

    A high performance gel imaging system was constructed using a digital single lens reflex camera with epi-illumination to image 19 × 23 cm agarose gels with up to 10,000 DNA bands each. It was found to give equivalent performance to a laser scanner in this high throughput DNA fingerprinting application using the fluorophore SYBR Green®. The specificity and sensitivity of the imager and scanner were within 1% using the same band identification software. Low and high cost color filters were also compared and it was found that with care, good results could be obtained with inexpensive dyed acrylic filters in combination with more costly dielectric interference filters, but that very poor combinations were also possible. Methods for determining resolution, dynamic range, and optical efficiency for imagers are also proposed to facilitate comparison between systems.

  13. Dataset of gene cloning and gel filtration chromatography of R-est6

    PubMed Central

    Soni, Surabhi; Odaneth, Annamma A.; Lali, Arvind M.; Chandrayan, Sanjeev K.

    2016-01-01

    The data presented in this article are connected to the research article entitled “Expression, purification and biochemical characterization of a family 6 carboxylesterase from Methylococcus capsulatus (bath)” (Soni et al., 2016 [1]). The family 6 carboxylesterases are the smallest and display broad substrate specificity. The 1 kb gene encoding, a family 6 carboxylesterase – R-est6, was amplified from the genome of M. capsulatus (bath strain), and showed in the agarose gel. The corresponding purified protein, after overexpression in Escherichia coli, was biochemically studied in the research article (Soni et al., 2016 [1]). R-est6 has hydrophobic patches on the surface so, it is expected to show oligimeric forms. Here, we have confirmed the presence of oligomers by gel filtration chromatography data and the proteins belonging to the different peaks are shown on a SDS-PAGE. PMID:27222859

  14. Examination of Interactions of Oppositely Charged Proteins in Gels

    SciTech Connect

    Ramasamy,P.; El-Maghrabi, M.; Halada, G.; Miller, L.; Rafailovich, M.

    2007-01-01

    Understanding the interactions of proteins with one another serves as an important step for developing faster protein separation methods. To examine protein-protein interactions of oppositely charged proteins, fluorescently labeled albumin and poly-L-lysine were subjected to electrophoresis in agarose gels, in which the cationic albumin and the anionic poly-L-lysine were allowed to migrate toward each other and interact. Fluorescence microscopy was used to image fluorescently tagged proteins in the gel. The secondary structure of the proteins in solution was studied using conventional FTIR spectroscopy. Results showed that sharp interfaces were formed where FITC tagged albumin met poly-L-lysine and that the interfaces did not migrate after they had been formed. The position of the interface in the gel was found to be linearly dependent upon the relative concentration of the proteins. The formation of the interface also depended upon the fluorescent tag attached to the protein. The size of the aggregates at the interface, the fluorescence intensity modifications, and the mobility of the interface for different pore sizes of the gel were investigated. It was observed that the interface was made up of aggregates of about 1 {mu}m in size. Using dynamic light scattering, it was observed that the size of the aggregates that formed due to interactions of oppositely charged proteins depended upon the fluorescent tags attached to the proteins. The addition of small amounts of poly-L-lysine to solutions containing FITC albumin decreased the zeta potential drastically. For this, we propose a model suggesting that adding small amounts of poly-L-lysine to solutions containing FITC -albumin favors the formation of macromolecular complexes having FITC albumin molecules on its surface. Although oppositely charged FITC tagged poly-L-lysine and FITC tagged albumin influence each other's migration velocities by forming aggregates, there were no observable secondary structural

  15. Rapid Detection of Glycogen Synthase Kinase-3 Activity in Mouse Sperm Using Fluorescent Gel Shift Electrophoresis

    PubMed Central

    Choi, Hoseok; Choi, Bomi; Seo, Ju Tae; Lee, Kyung Jin; Gye, Myung Chan; Kim, Young-Pil

    2016-01-01

    Assaying the glycogen synthase kinase-3 (GSK3) activity in sperm is of great importance because it is closely implicated in sperm motility and male infertility. While a number of studies on GSK3 activity have relied on labor-intensive immunoblotting to identify phosphorylated GSK3, here we report the simple and rapid detection of GSK3 activity in mouse sperm using conventional agarose gel electrophoresis and a fluorescent peptide substrate. When a dye-tethered and prephosphorylated (primed) peptide substrate for GSK3 was employed, a distinct mobility shift in the fluorescent bands on the agarose was observed by GSK3-induced phosphorylation of the primed peptides. The GSK3 activity in mouse testes and sperm were quantifiable by gel shift assay with low sample consumption and were significantly correlated with the expression levels of GSK3 and p-GSK3. We suggest that our assay can be used for reliable and rapid detection of GSK3 activity in cells and tissue extracts. PMID:27092510

  16. Separation of chromosomal DNA molecules from yeast by orthogonal-field-alternation gel electrophoresis.

    PubMed Central

    Carle, G F; Olson, M V

    1984-01-01

    A simple agarose-gel apparatus has been developed that allows the separation of DNA molecules in the size range from 50 kb to well over 750 kb, the largest size for which size standards were available. The apparatus is based on the recent discovery that large DNA molecules are readily fractionated on agarose gels if they are alternately subjected to two approximately orthogonal electric fields. The switching time, which was on the order of 20-50 sec in our experiments, can be adjusted to optimize fractionation in a given size range. The resolution of the technique is sufficient to allow the fractionation of a sample of self-ligated lambda DNA into a ladder of approximately 15 bands, spaced at 50 kb intervals. We have applied the technique to the fractionation of yeast DNA into 11 distinct bands, several of which have been shown by DNA-DNA hybridization to hybridize uniquely to different chromosome-specific hybridization probes. In this paper, we describe the design of the apparatus, the electrophoretic protocol, and the sample-handling procedures that we have employed. Images PMID:6379602

  17. Investigations on gel forming media use in low gravity bioseparations research

    NASA Technical Reports Server (NTRS)

    Todd, Paul; Szlag, David C.; Plank, Lindsay D.; Delcourt, Scott G.; Kunze, M. Elaine

    1989-01-01

    Research on gelling media and conditions suitable for the preservation of the spatial configuration of cell suspensions and macromolecular solutions after separation in free fluid during low gravity experiments is presented. The examples studied included free electrophoresis of cells in a cylindrical column and two-phase aqueous polymer separation. Microgravity electrophoresis experiments were simulated by separating model cell types (animal or human) in a vertical density gradient containing low-conductivity buffer, 1.7-6.5 percent Ficoll, 6.8-5.0 percent sucrose, and 1 percent SeaPrep low-melting temperature agarose. Upon cooling, a gel formed in the column and cells could be captured at the forming locations. Two-phase extraction experiments were simulated using two-polymer solutions in which phase separation occurs in normal saline at temperatures compatible with cell viability and in which one or both phases form a gel upon cooling. Suitable polymers included commercial agaroses (1-2 percent), maltodextrin (5-7 percent), and gelatin (5-20 percent).

  18. Rapid Detection of Glycogen Synthase Kinase-3 Activity in Mouse Sperm Using Fluorescent Gel Shift Electrophoresis.

    PubMed

    Choi, Hoseok; Choi, Bomi; Seo, Ju Tae; Lee, Kyung Jin; Gye, Myung Chan; Kim, Young-Pil

    2016-01-01

    Assaying the glycogen synthase kinase-3 (GSK3) activity in sperm is of great importance because it is closely implicated in sperm motility and male infertility. While a number of studies on GSK3 activity have relied on labor-intensive immunoblotting to identify phosphorylated GSK3, here we report the simple and rapid detection of GSK3 activity in mouse sperm using conventional agarose gel electrophoresis and a fluorescent peptide substrate. When a dye-tethered and prephosphorylated (primed) peptide substrate for GSK3 was employed, a distinct mobility shift in the fluorescent bands on the agarose was observed by GSK3-induced phosphorylation of the primed peptides. The GSK3 activity in mouse testes and sperm were quantifiable by gel shift assay with low sample consumption and were significantly correlated with the expression levels of GSK3 and p-GSK3. We suggest that our assay can be used for reliable and rapid detection of GSK3 activity in cells and tissue extracts. PMID:27092510

  19. 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.

  20. Sequential differentiation of mesenchymal stem cells in an agarose scaffold promotes a physis-like zonal alignment of chondrocytes.

    PubMed

    Schmitt, Jacqueline Frida; See, Kwee Hua; Hua, See Kwee; Yang, Zheng; Zheng, Yang; Hui, James Hoi Po; Po, James Hui Hoi; Lee, Eng Hin; Hin, Lee Eng

    2012-11-01

    Chondrocytes of the epiphyseal growth plate (physis) differentiate and mature in defined linear zones. The current study examines the differentiation of human bone marrow derived mesenchymal stem cells (hBMSCs) into zonal physeal cartilage. hBMSCs were embedded in an agarose scaffold with only the surface of the scaffold in direct contact with the culture medium. The cells were differentiated using a two-step system involving the sequential addition of TGFβ followed by BMP2. The resultant samples displayed a heterogenic population of physis-like collagen type 2 positive cells including proliferating chondrocytes and mature chondrocytes showing hypertrophy, expression of early bone markers and matrix mineralization. Histological analysis revealed a physis-like linear zonal alignment of chondrocytes in varying stages of differentiation. The less mature chondrocytes were seen at the base of the construct while hypertrophic chondrocytes and matrix mineralization was observed closer to the surface of the construct. The described differentiation protocol using hBMSCs in an agarose scaffold can be used to study the factors and conditions that influence the differentiation, proliferation, maturation, and zonal alignment of physeal chondrocytes. PMID:22517299

  1. Probing the transport of plasma-generated RONS in an agarose target as surrogate for real tissue: dependency on time, distance and material composition

    NASA Astrophysics Data System (ADS)

    Szili, Endre J.; Oh, Jun-Seok; Hong, Sung-Ha; Hatta, Akimitsu; Short, Robert D.

    2015-05-01

    We report a simple experimental approach to follow the transport of helium (He) plasma-generated reactive oxygen and nitrogen species (RONS) through millimetre thick agarose targets. These RONS may be either primary RONS, generated directly by the plasma jet, or secondary RONS generated for example at the surface of, or within, the material. Our experiment involves placing an agarose film over a quartz cuvette filled with deionized water. The agarose film is exposed to a He plasma jet and the UV absorption profile (of the deionized water) is recorded in real-time. Plasma exposure time, source-target distance and agarose film thickness and composition are varied to explore their effects on the depth of RONS delivery by the plasma jet. We conclude that plasma UV plays a minor role in the transport of RONS; whereas direct plasma contact and the He gas flow promote the transport of RONS into tissue. Our data indicate an accumulation of RONS within the agarose film (during plasma exposure) and a subsequent (time-lagged) release into the deionized water. Our approach can be readily adapted to other plasma sources; it can accommodate more complex biological materials, and has the potential to provide new insights into plasma-induced phenomena within real tissues.

  2. Improvement of proton exchange membrane fuel cell performance in low-humidity conditions by adding hygroscopic agarose powder to the catalyst layer

    NASA Astrophysics Data System (ADS)

    Hou, Sanying; Liao, Shijun; Xiong, Ziang; Zou, Haobin; Dang, Dai; Zheng, Ruiping; Shu, Ting; Liang, Zhenxing; Li, Xiuhua; Li, Yingwei

    2015-01-01

    A high-performance membrane electrode assembly (MEA) with agarose added to the anodic catalyst layer (CL) was successfully prepared. The MEA exhibited excellent performance at low relative humidity (RH) in an air/hydrogen proton exchange membrane fuel cell. The effects of agarose content, RH, cell temperature, and back pressure on the low-humidity performance of this MEA were investigated. The results of water contact angles and water uptake measurements reveal that the hydrophilicity of the anode is significantly improved with the addition of agarose. With a low RH of 20% and a cell temperature of 60 °C, the optimal MEA (MEA-4), containing 4 wt.% agarose in the anode CL, achieves excellent low-humidity performance: the current density reaches 960 mA cm-2 at 0.6 V and 500 mA cm-2 at 0.7 V. After 10 h of continuous operation under the same conditions, the current density decreases just slightly, from 960 to 840 mA cm-2, whereas the current density of a blank MEA without added agarose degrades sharply.

  3. Polymer gel as a barrier for ground oil spill containment

    SciTech Connect

    Wilkins, E.

    1996-12-31

    The specific problem that is of concern here is to stop or at least significantly retard the migration of oil spill and other waste fluids into groundwater. Stopping or slowing migration of contaminants will allow remediation of the source of the contaminants, or at least provide more time for the required remediation technology to be developed and applied. The solution proposed is to employ a polymer gel barrier that is highly impermeable to the contaminants of interest. The barrier will be formed by injection into the ground of ungelled polymer, which will then gel in controlled fashion in situ. The importance and innovation of this proposed technique lies in {open_quote}ungelled{close_quote}. The material to be injected via drill holes will have a viscosity and density close to water, hence the pump power and costs will be very low compared with other methods. Several promising polymer gels have been identified and tested for the purpose of forming effective barriers. The permeability of this gel barrier is very low, in the order of 10{sup {minus}8} - 10{sup {minus}9} cm/sec, which is much lower than 10{sup {minus}7} cm/sec - the criterion for an ideal barrier. Further, gelation time, which is an important factor in constructing a gel barrier, can be easily controlled by varying the pH of the ungelled polymer-crosslinking agent mixture.

  4. DNA Length Ranges Exhibiting Distinct Separation Mechanisms in Gel Electrophoresis

    NASA Astrophysics Data System (ADS)

    Beheshti, A.; van Winkle, D. H.; Rill, R. L.

    2003-03-01

    Electrophoresis was performed on double stranded DNA ranging from 200 to 194,000 bp in agarose gel concentrations from 0.4% - 1.3%. The electric field was varied from 0.62 to 6.21 V/cm. A wide range of electric fields and gel concentrations were used to study how the new interpolation equation, frac1μ(L) = frac1μL - (frac1μL - frac1μ_s)e^-L/γ (where μ_L, μ_s, and γ are independent free fitting parameters), helps to distinguish among different mechanisms of molecular transport. This exponential relation fits well when there is a smooth transition from Ogston sieving to reptation. These transitions are distinguished by so-called ``reptation plots" (plotting 3μ L/μ_rc vs. L) (J. Rousseau, G. Drouin, and G. W. Slater, Phys Rev Lett. 1997, 79, 1945-1948). Fits deviate from the data more than two characteristic trends are observed in the reptation plots. The failure of the fits to follow the data appears to be a consequence of another separation mechanism, ``entropic trapping," occurring between the sieving and reptation regimes. The boundaries between length and field ranges where different separation mechanisms dominate are extracted from reptation plots of the best fits and the data. ``Phase diagrams" expressing these boundaries are derived.

  5. Puberty in the Girl Who is Retarded.

    ERIC Educational Resources Information Center

    Pattullo, Ann

    Designed to help mothers of mentally retarded girls deal with the problems and concerns of puberty, the booklet provides information on physical and emotional changes, menstruation, masturbation, heterosexual behavior, contraception, protection against sexual aggression, the possibilities of marriage, and additional sources of information.…

  6. Do the Mentally Retarded Have Poor Memory?

    ERIC Educational Resources Information Center

    Ellis, Norman R.

    1978-01-01

    A reevaluation of a number of experiments suggests that normal and retarded persons differ on short-term memory tasks from the time of initial stimulus exposure. The hypothesis that memory differences are due to differential encoding as a result of more adequate rehearsal by the normal subjects is unacceptable. (Author/BW)

  7. Brominated flame retardants as food contaminants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter reviews analytical methods for the three major brominated flame retardant (BFR) classes in use today, tetrabromobisphenol-A (TBBP-A), hexabromocyclododecanes (HBCDs), and polybrominated diphenyl ethers (PBDEs), a "legacy" BFR no longer in use, polybrominated biphenyls (PBBs), and a...

  8. Aerobic Fitness for the Moderately Retarded.

    ERIC Educational Resources Information Center

    Bauer, Dan

    1981-01-01

    Intended for physical education teachers, the booklet offers ideas for incorporating aerobic conditioning into programs for moderately mentally retarded students. An explanation of aerobic fitness and its benefits is followed by information on initiating a fitness program with evaluation of height, weight, body fat, resting heart rate, and…

  9. BROMINATED FLAME RETARDANTS: CAUSE FOR CONCERN?

    EPA Science Inventory

    Brominated flame retardants (BFRs) have routinely been added to consumer products for several decades in a successful effort to reduce fire-related injury and property damage. Recently, concern for this emerging class of chemicals has risen due to the occurrence of several class...

  10. Novel additives to retard permeable flow

    SciTech Connect

    Golombok, Michael; Crane, Carel; Ineke, Erik; Welling, Marco; Harris, Jon

    2008-09-15

    Low concentrations of surfactant and cosolute in water, can selectively retard permeable flow in high permeability rocks compared to low permeability ones. This represents a way forward for more efficient areal sweep efficiency when water flooding a reservoir during improved oil recovery. (author)

  11. BROMINATED FLAME RETARDANTS: WHY DO WE CARE?

    EPA Science Inventory

    Brominated flame retardants (BFRs) save lives and property by preventing the spread of fires or delaying the time of flashover, enhancing the time people have to escape. The worldwide production of BFRs exceeded 200,000 metric tons in 2003 placing them in the high production vol...

  12. Jean Piaget Archives Bibliography on Mental Retardation.

    ERIC Educational Resources Information Center

    Bolton, Susie; And Others

    This bibliography lists all entries from the Jean Piaget Archives Catalogues dealing with mental retardation. The list, including almost 200 entries, encompasses four works by Piaget himself, one collaboration, and 189 works by other authors. Entries are arranged in order by their publication in one of the 12 catalogues of the archives, providing…

  13. Abandoning the Myth of Mental Retardation

    ERIC Educational Resources Information Center

    Smith, J. David

    2003-01-01

    In this article, the author talks about the concept underlying the term metal retardation and the effort to define it in a way that is scientifically accurate and in a way that promotes greater sensitivity to the needs of people described by the term which has been continuous for centuries. The author states that a scientifically sound and…

  14. Computer Assisted Instruction for the Mentally Retarded.

    ERIC Educational Resources Information Center

    Providence Coll., RI.

    Computer Assisted Instruction (CAI) for the mentally retarded is described; the advantages of CAI (which generally follows the pattern of programed instruction) are listed; and the roles of the teacher and the student are summarized. The coursewriter is explained, and its use as an experimental tool discussed. Guidelines are given covering…

  15. Language Transference by Mentally Retarded Spanish Speakers.

    ERIC Educational Resources Information Center

    Flaherty, Carol

    In an investigation of language transference vs. language interference, 12 trainable mentally retarded Spanish speakers (5 to 9 years old) were trained to name in English objects previously identified receptively and objects not previously identified receptively in Spanish. Results indicated no significant difference in the number of words learned…

  16. Implementing Programs for Trainable Mentally Retarded Children.

    ERIC Educational Resources Information Center

    Indiana State Dept. of Public Instruction, Indianapolis.

    Guidelines for the development of programs for trainable mentally retarded children are presented. Major task areas identified are the family group, communication skills, physical development, socialization, recreational interests and skills, and preparation for work oriented activity. Six papers are presented: precision teaching and behavior…

  17. READINESS AND READING FOR THE RETARDED CHILD.

    ERIC Educational Resources Information Center

    BERNSTEIN, BEBE

    THIS TEACHER'S BOOK AND MANUAL, DESIGNED TO ACCOMPANY TWO WORKBOOKS, PRESENTS A FUNCTIONAL APPROACH TO READINESS AND READING FOR YOUNG EDUCABLE RETARDED CHILDREN. THE WORKBOOKS THEMSELVES OFFER PREPARATORY ACTIVITIES FOR CHILDREN AT THE READINESS LEVEL AND SEQUENTIAL ACTIVITIES AND MATERIALS FOR THOSE AT THE BEGINNING READING STAGE. THE TEACHER'S…

  18. Improving Outcomes for Workers with Mental Retardation

    ERIC Educational Resources Information Center

    Fornes, Sandra; Rocco, Tonette S.; Rosenberg, Howard

    2008-01-01

    This research presents an analysis of factors predicting job retention, job satisfaction, and job performance of workers with mental retardation. The findings highlight self-determination as a critical skill in predicting the three important employee outcomes. The study examined a hypothesized job retention model and the outcome of the three…

  19. Noncompliant Behavior of People with Mental Retardation.

    ERIC Educational Resources Information Center

    Walker, Rex G.

    1993-01-01

    This literature review on antecedents, behaviors, and consequences in the noncompliant behavior of people with mental retardation found that noncompliance is more likely when instructions are vague or task demands are too difficult and that noncompliance responds well to programs utilizing combinations of social and tangible rewards. (Author/JDD)

  20. New fire retardant foams and intumescents

    NASA Technical Reports Server (NTRS)

    Parker, J. A.

    1972-01-01

    The development of fire retardant foams and intumescent paints for protection of commercial aircraft passengers in the event of fire is discussed. Recommended materials and methods for evaluating the effectiveness of the materials are presented. Typical problems resulting from aircraft fires and the basic protective mechanisms to cope with these problems are examined.

  1. Teaching the Mentally Retarded Job Interviewing Skills

    ERIC Educational Resources Information Center

    Grinnell, Jr., Richard M.; Lieberman, Alice

    1977-01-01

    Examined the most effective usage of videotape in job interview skill training for 24 mentally retarded young adults utilizing the microcounseling model of instruction. Data revealed the microcounseling model is most effective with the two skill areas of eye contact and body posture regardless of the method of videotape utilization. (Author)

  2. Mental Retardation: Past, Present and Future

    ERIC Educational Resources Information Center

    Crissey, Marie Skodak

    1975-01-01

    Notes that two developments had major impacts on policies towards the mentally retarded between the 1880s and the 1920s: (1) the swing toward the eugenics-heredity-genetics movement, and (2) the development of individual intelligence testing. (Author/JM)

  3. Euthanasia and Mental Retardation: Suggesting the Unthinkable.

    ERIC Educational Resources Information Center

    Hollander, Russell

    1989-01-01

    The article examines current opinions toward euthanasia of persons with mental retardation in light of the history of public and professional attitudes. It also discusses the rejection of euthanasia on moral and religious grounds, and notes the use of lifelong incarceration, based on eugenics principles, to accomplish similar ends. (DB)

  4. HEALTH ASPECTS OF BROMINATED FLAME RETARDANTS (BFRS)

    EPA Science Inventory

    In order to reduce the societal costs of fires, flammability standards have been set for consumer products and equipment. Flame retardants containing bromine have constituted the largest share of this market due both to their efficiency and cost. While there are at least 75 dif...

  5. STUDYING LEARNING PATTERNS IN MENTAL RETARDATES.

    ERIC Educational Resources Information Center

    CANDLAND, DOUGLAS K.; MANNING, SIDNEY ALPERN

    FIVE EXPERIMENTS WERE CONDUCTED IN AN ATTEMPT TO ISOLATE SPECIFIC LEARNING PATTERNS IN CHILDREN OF VARYING DEGREES OF MENTAL RETARDATION AND TO CONTRIBUTE TO THE KNOWLEDGE OF THE PHYLOGENETIC DEVELOPMENT OF INTELLIGENCE. FACTORS STUDIED WERE THOSE KNOWN TO INFLUENCE LEARNING IN NORMAL CHILDREN AND ADULTS--KIND OF REINFORCEMENT (VERBAL OR…

  6. Ophthalmologic Screening of Adults with Mental Retardation.

    ERIC Educational Resources Information Center

    Sacks, Joel G.; And Others

    1991-01-01

    Ophthalmological screening was conducted on 113 clients in a work activity center for adults with mental retardation. Abnormalities that were neither refractive nor strabismic were found in 32 percent of clients. Findings suggest the value of conducting screenings in settings familiar to such clients. (Author/DB)

  7. HEALTH EFFECTS OF BROMINATED FLAME RETARDANTS (BFRS)

    EPA Science Inventory

    Abstract Brominated flame retardant use has increased dramatically in order to provide fire safety to consumers. However, there is growing concern about widespread environmental contamination and potential health risks from some of these products. The most used products...

  8. Vocational Horticulture for Persons with Mental Retardation.

    ERIC Educational Resources Information Center

    Kern, William H.; And Others

    The study explored methods and techniques for training mentally retarded adults to perform gardening tasks. A total of 31 subjects ages 21 to 48 (IQ range 32-89) participated in the study, which consisted of three phases. In an initial pilot study, experimentation without subjects resulted in the development of modified tools (e.g., notched…

  9. Teaching Laundry Skills to Mentally Retarded Students.

    ERIC Educational Resources Information Center

    Cuvo, Anthony J.; And Others

    1981-01-01

    Five moderately and mildly retarded students (19 to 21 years old) were taught to sort garments to be laundered and to use a clothes washer and dryer. Rapid acquisition and maintenance of the laundry skills were obtained through praise and response contingent feedback as a consequence for behavior. (Author/CL)

  10. Aging, Mental Retardation and Physical Fitness.

    ERIC Educational Resources Information Center

    Rimmer, James H.

    This fact sheet uses a question-and-answer format to provide an overview of what physical fitness is and how it relates to people with mental retardation. Questions address the following topics: the fitness movement; a definition of physical fitness; the different components of physical fitness (muscle strength and endurance, flexibility, body…

  11. PARENT ATTITUDES IN REARING MENTALLY RETARDED CHILDREN.

    ERIC Educational Resources Information Center

    LEICHMAN, NATHAN S.; WILLENBERG, ERNEST P.

    POSITIVE AND NEGATIVE ASPECTS OF REARING MENTAL RETARDATES WERE IDENTIFIED AND MEASURED DURING THIS STUDY BY EXAMINATIONS OF PARENTAL ATTITUDES AND HOW THESE ATTITUDES OFTEN AFFECT THE DAILY BEHAVIOR AND LEARNING READINESS OF CHILDREN WHILE IN SCHOOL. BEHAVIORAL FACTORS OF THE INDIVIDUAL CHILD WERE ANALYZED AND COMPARED WITH STATISTICS COVERING…

  12. Fully variable elliptical phase retarder composed of two linear phase retarders

    NASA Astrophysics Data System (ADS)

    Yu, Chih-Jen

    2016-03-01

    In this study, a fully variable elliptical phase retarder was developed by combining a variable linear phase retarder and a half-wave plate. All three polarization parameters of the elliptical phase retarder (elliptical phase retardation γ, azimuth angle θ, and ellipticity angle ɛ) were adjustable. Experimental verification was performed by measuring the polarization parameters with a polarizer-sample-analyzer polarimeter. The polarization parameters were set to γ = 120°, ɛ = 15°, and θ = 20°. The measurement results, γ = 119.838° ± 0.006°, ɛ = 14.659° ± 0.002°, and θ = 20.084° ± 0.002°, agreed with theoretical prediction.

  13. 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.

  14. Flame Retardant Effect of Aerogel and Nanosilica on Engineered Polymers

    NASA Technical Reports Server (NTRS)

    Williams, Martha K.; Smith, Trent M.; Roberson, Luke B.; Yang, Feng; Nelson, Gordon L.

    2010-01-01

    Aerogels are typically manufactured vIa high temperature and pressure-critical-point drying of a colloidal metal oxide gel filled with solvents. Aerogel materials derived from silica materials represent a structural morphology (amorphous, open-celled nanofoams) rather than a particular chemical constituency. Aerogel is not like conventional foams in that it is a porous material with extreme microporosity and composed of individual features only a few nanometers in length with a highly porous dendriticlike structure. This unique substance has unusual properties such as low thermal conductivity, refractive index and sound suppression; in addition to its exceptional ability to capture fast moving dust. The highly porous nature of the aerogel's structure provides large amounts of surface area per unit weight. For instance, a silica aerogel material with a density of 100 kilograms per cubic meters can have surface areas of around 800 to 1500 square meters per gram depending on the precursors and process utilized to produce it. To take advantage of the unique properties of silica aerogels, especially the ultra light weight and low thermal conductivity, their composites with various engineering polymers were prepared and their flammability was investigated by Cone Calorimetry. The flammability of various polystyrene/silica aerogel nanocomposites were measured. The combination of these nanocomposites with a NASA patented flame retardant SINK were also studied. The results were compared with the base polymer to show the differences between composites with different forms of silica.

  15. Cardiovascular Risk Factor Levels in Adults with Mental Retardation.

    ERIC Educational Resources Information Center

    Rimmer, James H.; And Others

    1994-01-01

    Comparison of cardiovascular risk factors (blood lipids, obesity, and smoking) in 329 adults with mental retardation residing in various settings with subjects in the Framingham Offspring Study found that adults with mental retardation had cardiovascular risk profiles similar to those of individuals without mental retardation. (Author/DB)

  16. Mental Retardation: The Search for Cures. Research Monograph Number 7.

    ERIC Educational Resources Information Center

    Menolascino, Frank J.; Neman, Ronald

    The booklet describes the Association for Retarded Citizens' (ARC's) goal of coordinating efforts to seek a cure for mental retardation. Cures are defined as any intervention that would significantly increase intellectual functioning and adaptive behavior beyond the upper level of retardation. It is explained that because of the variety of causes…

  17. The Problem of Typological Thinking in Mental Retardation.

    ERIC Educational Resources Information Center

    Gelb, Steven A.

    1997-01-01

    Asserts that typological thinking, the belief that individual differences diverge around an underlying type of essence, has persisted regarding mental retardation and prevents the appreciation of individual differences and human dignity in the mental retardation field. Past and present controversies over the definition of mental retardation are…

  18. Low Elevated Lead Levels and Mild Mental Retardation.

    ERIC Educational Resources Information Center

    Marlowe, Mike; And Others

    To investigate the relation between low level lead absorption and mild mental retardation, hair lead concentrations were compared in a group of 40 mildly retarded children "etiology unknown" with a control group of 20 children. Children with probable cause for retardation were excluded from the sample as were children with a history of lead…

  19. Attitudes of High School Students toward Individuals with Mental Retardation.

    ERIC Educational Resources Information Center

    Krajewski, Junean; Flaherty, Thomas

    2000-01-01

    The attitudes of 144 high school students toward individuals with mental retardation were examined using the Mental Retardation Attitude Inventory-Revised. Results indicated that gender and frequency of contact both influenced attitudes. Females and students with more frequent contacts with individuals with mental retardation indicated more…

  20. Conjunctive Visual Search in Individuals with and without Mental Retardation

    ERIC Educational Resources Information Center

    Carlin, Michael; Chrysler, Christina; Sullivan, Kate

    2007-01-01

    A comprehensive understanding of the basic visual and cognitive abilities of individuals with mental retardation is critical for understanding the basis of mental retardation and for the design of remediation programs. We assessed visual search abilities in individuals with mild mental retardation and in MA- and CA-matched comparison groups. Our…

  1. Neuropsychological Profiles of Persons with Mental Retardation and Dementia

    ERIC Educational Resources Information Center

    Palmer, Glen A.

    2006-01-01

    This study examined the use of neuropsychological tests to assist in the differential diagnosis of dementia among persons with mental retardation. The author compared performances of persons with mental retardation and dementia ("n" = 10) to persons with mental retardation without dementia ("n" = 12). Participants were matched by IQ (mild or…

  2. Stimulus Overselectivity: A Common Feature in Autism and Mental Retardation

    ERIC Educational Resources Information Center

    Lovaas, O. Ivar; Wilhelm, Hannelore

    1976-01-01

    Overselective attention in discrimination between picture cards was investigated with three groups of children with different IQ levels: 10 severely retarded (IQ = 29 - 51, CA = 9.6 - 18 years), 10 moderately retarded (IQ = 56 - 85, CA = 12.8 - 16.3 years), and 10 non-retarded (CA = 10 - 12 years). (Author/IM)

  3. Repair Behaviors of Children with and without Mental Retardation.

    ERIC Educational Resources Information Center

    Scudder, Rosalind R.; Tremain, Deborah Hobbs

    1992-01-01

    Communication repair behaviors of 10 children with mental retardation (ages 11-13) and 10 mental age-matched children without mental retardation were examined. The children with mental retardation did not respond as often and rarely used details to expand their utterances. Results have implications for the development of conversational skills in…

  4. Motor Task Persistence of Children with and without Mental Retardation.

    ERIC Educational Resources Information Center

    Kozub, Francis M.; Porretta, David L.; Hodge, Samuel R.

    2000-01-01

    Task persistence by 31 children (ages 9-13) with and without mental retardation during two challenging motor tasks was investigated. A main effect was found for group affiliation: children without mental retardation attempted more trials over three sessions. Results indicated children with mental retardation were less persistent than typical…

  5. Guidelines for Library Services for People with Mental Retardation.

    ERIC Educational Resources Information Center

    Association of Specialized and Cooperative Library Agencies, Chicago, IL.

    This guide is designed to assist all libraries, including school, public, academic, and specialized libraries such as prison and institutional libraries, to better serve the needs of people of all ages who are mentally retarded. An overview provides a definition of mental retardation, places services for people with mental retardation in…

  6. Serving Young Children Whose Parents Are Mentally Retarded.

    ERIC Educational Resources Information Center

    Lynch, Eleanor W.; Bakley, Sue

    1989-01-01

    The article reviews the cognitive and social/emotional characteristics associated with mental retardation, the literature on parents with mental retardation, and the interaction between these characteristics in relation to child abuse and neglect. Three case studies of mentally retarded parents illustrate the range of problems and needs service…

  7. Older Mentally Retarded Persons: Demographic Profile and Service Requirements.

    ERIC Educational Resources Information Center

    Seltzer, Marsha Mailick

    An overview is presented on current knowledge about elderly mentally retarded persons. Definitional and incidence issues are addressed, and support is voiced for use of a lower cut-off for the beginning of old age among the retarded than for the general population. Conflicting findings of age-related differences in mentally retarded adults are…

  8. Gel-assisted crystallization of [Ir4(IMe)7(CO)H10](2+) and [Ir4(IMe)8H9](3+) clusters derived from catalytic glycerol dehydrogenation.

    PubMed

    Sharninghausen, Liam S; Mercado, Brandon Q; Crabtree, Robert H; Balcells, David; Campos, Jesús

    2015-11-14

    The two title clusters were formed during iridium-catalyzed glycerol dehydrogenation and display a remarkably high NHC content. They were crystallized in either agarose or polyethylene oxide gel matrices, while more conventional crystallization techniques proved unsuccessful. Cluster [Ir4(IMe)8H9](3+), with a net charge of +3, was only crystallizable with a polyoxometalate Keggin trianion. The crystal packing of this intercluster compound is discussed. Computational studies position the iridium hydrides and provide insights into the bonding. PMID:26435314

  9. 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.

  10. Brominated flame retardants: cause for concern?

    PubMed Central

    Birnbaum, Linda S; Staskal, Daniele F

    2004-01-01

    Brominated flame retardants (BFRs) have routinely been added to consumer products for several decades in a successful effort to reduce fire-related injury and property damage. Recently, concern for this emerging class of chemicals has risen because of the occurrence of several classes of BFRs in the environment and in human biota. The widespread production and use of BFRs; strong evidence of increasing contamination of the environment, wildlife, and people; and limited knowledge of potential effects heighten the importance of identifying emerging issues associated with the use of BFRs. In this article, we briefly review scientific issues associated with the use of tetrabromobisphenol A, hexabromocyclododecane, and three commercial mixtures of polybrominated diphenyl ethers and discuss data gaps. Overall, the toxicology database is very limited; the current literature is incomplete and often conflicting. Available data, however, raise concern over the use of certain classes of brominated flame retardants. PMID:14698924

  11. [Curing mental retardation: searching for balance].

    PubMed

    Harel, Sharon; Jenna, Sarah

    2011-01-01

    Mental retardation (MR) occurs in 2 to 3 % of the general population and is still not therapeutically addressed. Milder forms of MR result from deficient synaptogenesis and/or impaired synaptic plasticity during childhood. These alterations would result from disequilibrium in signalling pathways regulating the balance between long term potentiation (LTP) and long term depression (LTD) in certain neurons such as hippocampus neurons. To provide mentally retarded children with increased cognitive abilities, novel experimental approaches are currently being developed to characterize signalling status associated with MR and to identify therapeutic targets that would restore lost equilibrium. Several studies also highlighted the major role played by molecular switches like kinases, phosphatases, small G proteins and their regulators in the coordination and integration of signalling pathways associated with synaptic plasticity. These proteins may therefore constitute promising therapeutic targets for a number of cognitive deficiencies. PMID:21299965

  12. Fabricating silver nanoplate/hybrid silica gel glasses and investigating their nonlinear optical absorption behavior

    NASA Astrophysics Data System (ADS)

    Zheng, Chan; Wenzhe, Chen; Xiaoyun, Ye; Cai, Shuguang; Xiao, Xueqing

    2014-03-01

    Silver nanoplate/hybrid silica gel glasses were prepared via the sol-gel technique. Analysis of ultraviolet-visible spectroscopy extinction spectra confirmed the successful incorporation of silver nanoplates into the hybrid silica gel glasses. The silver nanoplate/hybrid silica gel glass composites are completely noncrystalline because of their low doping level compared with that of the silica matrix. The nonlinear optical absorption behavior of the silver nanoplate/hybrid silica gel glass composites was studied via open-aperture Z-scan technique with 4 ns pulse durations at 532 nm and 1064 nm. The nonlinear optical properties of silver nanoplates are maintained after they were introduced into silica gel glasses. Furthermore, the silver nanoplate/hybrid silica gel glasses exhibit intensity-dependent transformation from saturable absorption (SA) to reverse saturable absorption (RSA). The SA behavior at low excitation intensity can be attributed to the bleaching of ground-state surface plasmon resonance absorption induced by the retarded electronic relaxation process in solid-state gel glasses. By contrast, the RSA at high incident influence may have resulted from excited-state absorption and two-photon absorption.

  13. Chemistry and toxicity of flame retardants for plastics.

    PubMed Central

    Liepins, R; Pearce, E M

    1976-01-01

    An overview of commercially used flame retardants is give. The most used flame retardants are illustrated and the seven major markets, which use 96% of all flame-retarded polymers, are described. Annual flame retardant growth rate for each major market is also projected. Toxicity data are reviewed on only those compositions that are considered commercially significant today. This includes 18 compounds or families of compounds and four inherently flame-retarded polymers. Toxicological studies of flame retardants for most synthetic materials are of recent origin and only a few of the compounds have been evaluated in any great detail. Considerable toxicological problems may exist in the manufacturing of some flame retardants, their by-products, and possible decomposition products. PMID:1026419

  14. 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

  15. Gel mobility shift assays for RNA binding viral RNAi suppressors.

    PubMed

    Csorba, Tibor; Burgyán, József

    2011-01-01

    The host-virus interaction is a continuous coevolutionary race involving both host defence strategies and virus escape mechanisms. RNA silencing is one of the main processes employed by eukaryotic organisms to fight viruses. However, viruses encode suppressor proteins to counteract this antiviral mechanism. Virtually all plant viruses encode at least one suppressor. In spite of being highly diverse at the protein level, a large group of these proteins inhibit RNA silencing very similarly, by sequestration of double-stranded RNA or small-interfering RNA molecules, the central players of the pathway. The RNA binding capacity of virus suppressor proteins can be studied by the electrophoretic mobility shift assay method. Also known as gel retardation assay, gel mobility assay, gel shift assay or band shift assay, EMSA is an in vitro technique used to characterize protein:DNA or protein:RNA interactions. The method had been developed based on the observation that protein: nucleic acid complexes migrate slower through a non-denaturing polyacrylamide gel than the free nucleic acid fragments. Here, we provide a detailed protocol for the analysis of crucifer-infecting Tobacco mosaic tobamovirus (cr-TMV) silencing suppressor protein p122 RNA binding capacity. PMID:21431690

  16. Evaluation of the Effects of Injection Velocity and Different Gel Concentrations on Nanoparticles in Hyperthermia Therapy

    PubMed Central

    Javidi, M; Heydari, M; Karimi, A; Haghpanahi, M; Navidbakhsh, M; Razmkon, A

    2014-01-01

    Background and objective: In magnetic fluid hyperthermia therapy, controlling temperature elevation and optimizing heat generation is an immense challenge in practice. The resultant heating configuration by magnetic fluid in the tumor is closely related to the dispersion of particles, frequency and intensity of magnetic field, and biological tissue properties. Methods: In this study, to solve heat transfer equation, we used COMSOL Multiphysics and to verify the model, an experimental setup has been used.  To show the accuracy of the model, simulations have been compared with experimental results. In the second part, by using experimental results of nanoparticles distribution inside Agarose gel according to various gel concentration, 0.5%, 1%, 2%, and 4%, as well as the injection velocity, 4 µL/min, 10 µL/min, 20 µL/min, and 40 µL/min, for 0.3 cc magnetite fluid, power dissipation inside gel has been calculated and used for temperature prediction inside of the gel. Results: The Outcomes demonstrated that by increasing the flow rate injection at determined concentrations, mean temperature drops. In addition, 2% concentration has a higher mean temperature than semi spherical nanoparticles distribution. Conclusion: The results may have implications for treatment of the tumor and any kind of cancer diseases. PMID:25599061

  17. A CCD-based system for the detection of DNA in electrophoresis gels by UV absorption

    NASA Astrophysics Data System (ADS)

    Mahon, Alex R.; MacDonald, John H.; Ott, Robert J.; Mainwood, Alison

    1999-06-01

    A method and apparatus for the detection and quantification of large fragments of unlabelled nucleic acids in agarose gels is presented. The technique is based on ultraviolet (UV) absorption by nucleotides. A deuterium source illuminates individual sample lanes of an electrophoresis gel via an array of optical fibres. As DNA bands pass through the illuminated region of the gel the amount of UV light transmitted is reduced because of absorption by the DNA. During electrophoresis the regions of DNA are detected on-line using a UV-sensitive charge coupled device (CCD). As the absorption coefficient is proportional to the mass of DNA the technique is inherently quantitative. The mass of DNA in a region of the gel is approximately proportional to the integrated signal in the corresponding section of the CCD image. This system currently has a detection limit of less than 1.25 ng compared with 2-10 ng for the most popular conventional technique, ethidium bromide (EtBr) staining. In addition the DNA sample remains in its native state. The removal of the carcinogenic dye from the detection procedure greatly reduces associated biological hazards.

  18. High speed memory scanning in retarded and non-retarded adolescents.

    PubMed

    Todman, J; Gibb, C M

    1985-02-01

    Four groups of 13-14-year-olds, classified on the basis of Raven's Progressive Matrices scores as intellectually above average, average, below average and retarded, were subjects in a Sternberg (1966) type memory scanning task in which memory sets of two, three and four letters were used. Slope values of the memory search function did not differ between groups, whereas intercept values decreased with higher intelligence up to the average intelligence level. There was an overall inverse relation between intercept values and intelligence (r = -0.77) and similar relations obtained within the three non-retarded groups (rs greater than or equal to -0.57), but not within the retarded group (r = -0.06). Possible connections between these results and findings from inspection time studies are discussed. PMID:3978355

  19. Pulsed-field gel electrophoresis (PFGE): application in population structure studies of bovine mastitis-causing streptococci.

    PubMed

    Santos-Sanches, Ilda; Chambel, Lélia; Tenreiro, Rogério

    2015-01-01

    Pulsed-field gel electrophoresis (PFGE) separates large DNA molecules by the use of an alternating electrical field, such that greater size resolution can be obtained when compared to normal agarose gel electrophoresis. PFGE is often employed to track pathogens and is a valuable typing scheme to detect and differentiate strains. Particularly, the contour-clamped homogeneous electric field (CHEF) PFGE system is considered to be the gold standard for use in epidemiological studies of many bacterial pathogens. Here we describe a PFGE protocol that was applicable to the study of bovine streptococci, namely, Streptococcus agalactiae (group B Streptococcus, GBS), Streptococcus dysgalactiae subsp. dysgalactiae (group C Streptococcus, GCS), and Streptococcus uberis-which are relevant pathogens causing mastitis, a highly prevalent and costly disease in dairy industry due to antibiotherapy and loss in milk production. PMID:25399106

  20. Electrode contamination effects of retarding potential analyzer.

    PubMed

    Fang, H K; Oyama, K-I; Cheng, C Z

    2014-01-01

    The electrode contamination in electrostatic analyzers such as Langmuir probes and retarding potential analyzers (RPA) is a serious problem for space measurements. The contamination layer acts as extra capacitance and resistance and leads to distortion in the measured I-V curve, which leads to erroneous measurement results. There are two main effects of the contamination layer: one is the impedance effect and the other is the charge attachment and accumulation due to the capacitance. The impedance effect can be reduced or eliminated by choosing the proper sweeping frequency. However, for RPA the charge accumulation effect becomes serious because the capacitance of the contamination layer is much larger than that of the Langmuir probe of similar dimension. The charge accumulation on the retarding potential grid causes the effective potential, that ions experience, to be changed from the applied voltage. Then, the number of ions that can pass through the retarding potential grid to reach the collector and, thus, the measured ion current are changed. This effect causes the measured ion drift velocity and ion temperature to be changed from the actual values. The error caused by the RPA electrode contamination is expected to be significant for sounding rocket measurements with low rocket velocity (1-2 km/s) and low ion temperature of 200-300 K in the height range of 100-300 km. In this paper we discuss the effects associated with the RPA contaminated electrodes based on theoretical analysis and experiments performed in a space plasma operation chamber. Finally, the development of a contamination-free RPA for sounding rocket missions is presented. PMID:24517809

  1. Nanotechnology finding its way into flame retardancy

    NASA Astrophysics Data System (ADS)

    Schartel, Bernhard

    2014-05-01

    Nanotechnology is one of the key technologies of the 21st century. The exploitation of "new" effects that arise from materials structured on the nano-scale has also been proposed successfully for flame retardancy of polymers since the end of the 90s. Of all of the approaches these include, at this time the use of nanocomposites offers the best potential for industrial application, also some other ideas are sketched, such as using electrospun nanofibers mats or layer-by-layer deposits as protection coatings, as well as sub-micrometer multilayer coatings as effective IR-mirrors. The general phenomena, inducing a flow limit in the pyrolysing melt and changing the fire residue, are identified in nanocomposites. Key experiments are performed such as quasi online investigation of the protection layer formation to understand what is going on in detail. The flame retardancy mechanisms are discussed and their impact on fire behaviour quantified. With the latter, the presentation pushes forward the state of the art. For instance, the heat shielding is experimentally quantified for a layered silicate epoxy resin nanocomposite proving that it is the only import mechanism controlling the reduction in peak heat release rate in the investigated system for different irradiations. The flame retardancy performance is assessed comprehensively illuminating not only the strengths but also the weak points of the concepts. Guidelines for materials development are deduced and discussed. Apart from inorganic fillers (layered silicate, boehmite, etc.) not only carbon nanoobjects such as multiwall carbon nanotubes, multilayer graphene and graphene are investigated, but also nanoparticles that are more reactive and harbor the potential for more beneficial interactions with the polymer matrix.

  2. Nanotechnology finding its way into flame retardancy

    SciTech Connect

    Schartel, Bernhard

    2014-05-15

    Nanotechnology is one of the key technologies of the 21{sup st} century. The exploitation of 'new' effects that arise from materials structured on the nano-scale has also been proposed successfully for flame retardancy of polymers since the end of the 90s. Of all of the approaches these include, at this time the use of nanocomposites offers the best potential for industrial application, also some other ideas are sketched, such as using electrospun nanofibers mats or layer-by-layer deposits as protection coatings, as well as sub-micrometer multilayer coatings as effective IR-mirrors. The general phenomena, inducing a flow limit in the pyrolysing melt and changing the fire residue, are identified in nanocomposites. Key experiments are performed such as quasi online investigation of the protection layer formation to understand what is going on in detail. The flame retardancy mechanisms are discussed and their impact on fire behaviour quantified. With the latter, the presentation pushes forward the state of the art. For instance, the heat shielding is experimentally quantified for a layered silicate epoxy resin nanocomposite proving that it is the only import mechanism controlling the reduction in peak heat release rate in the investigated system for different irradiations. The flame retardancy performance is assessed comprehensively illuminating not only the strengths but also the weak points of the concepts. Guidelines for materials development are deduced and discussed. Apart from inorganic fillers (layered silicate, boehmite, etc.) not only carbon nanoobjects such as multiwall carbon nanotubes, multilayer graphene and graphene are investigated, but also nanoparticles that are more reactive and harbor the potential for more beneficial interactions with the polymer matrix.

  3. Strategies for the crystallization of viruses: using phase diagrams and gels to produce 3D crystals of Grapevine fanleaf virus.

    PubMed

    Schellenberger, Pascale; Demangeat, Gérard; Lemaire, Olivier; Ritzenthaler, Christophe; Bergdoll, Marc; Oliéric, Vincent; Sauter, Claude; Lorber, Bernard

    2011-05-01

    The small icosahedral plant RNA nepovirus Grapevine fanleaf virus (GFLV) is specifically transmitted by a nematode and causes major damage to vineyards worldwide. To elucidate the molecular mechanisms underlying the recognition between the surface of its protein capsid and cellular components of its vector, host and viral proteins synthesized upon infection, the wild type GFLV strain F13 and a natural mutant (GFLV-TD) carrying a Gly₂₉₇Asp mutation were purified, characterized and crystallized. Subsequently, the geometry and volume of their crystals was optimized by establishing phase diagrams. GFLV-TD was twice as soluble as the parent virus in the crystallization solution and its crystals diffracted X-rays to a resolution of 2.7 Å. The diffraction limit of GFLV-F13 crystals was extended from 5.5 to 3 Å by growth in agarose gel. Preliminary crystallographic analyses indicate that both types of crystals are suitable for structure determination. Keys for the successful production of GFLV crystals include the rigorous quality control of virus preparations, crystal quality improvement using phase diagrams, and crystal lattice reinforcement by growth in agarose gel. These strategies are applicable to the production of well-diffracting crystals of other viruses and macromolecular assemblies. PMID:21352920

  4. New hybrid halogen-free flame retardants

    NASA Astrophysics Data System (ADS)

    Kijowska, Dorota; Jankowski, Piotr

    2014-05-01

    The main objective of this work were researches concerning the methods of the in-situ modification of silicate layer-tubular mineral (SL-TM) halloysite, using the salts of melamine, i.e. melamine cyanurate. The modified mineral was used as flame retardant to thermoplastic polymers. In the case of the application of halloysite modified by melamine cyanurate to polyamide 6 (PA6) the highest parameters of vertical and horizontal flammability were achieved. The mechanical properties of filled polyamide 6 have been improved.

  5. Retardation of nanoparticles growth by doping

    NASA Astrophysics Data System (ADS)

    Nosenko, Valentyna; Rudko, Galyna; Fediv, Volodymyr; Savchuk, Andrij; Gule, Evgenij; Vorona, Igor

    2014-12-01

    The process of doping of CdS nanoparticles with Mn during colloidal synthesis is analyzed by EPR and optical studies. Analysis of EPR results demonstrated that Mn2+ ions are successfully incorporated into the nanoparticles and occupy the crystal sites both in the bulk of a NP and near the surface of a NP. Optical absorption measurements revealed the retardation of absorption edge shift during the growth for Mn-doped CdS NPs as compared to the undoped CdS NPs. It was concluded that the presence of Mn in the solution leads to the inhibition of NPs growth.

  6. Optimization of retardance for a complete Stokes polarimeter

    SciTech Connect

    Sabatke, D. S.; Descour, M. R.; Dereniak, E. L.; Sweatt, W. C.; Kemme, S. A.; Phipps, G. S.

    2000-06-01

    We present two figures of merit based on singular value decomposition, which can be used to assess the noise immunity of a complete Stokes polarimeter. These are used to optimize a polarimeter featuring a rotatable retarder and a fixed polarizer. A retardance of 132 degree sign (approximately three-eighths wave) and retarder orientation angles of {+-}51.7{sup (convolution} {sup sign)} and {+-}15.1{sup (convolution} {sup sign)} are found to be optimal when four measurements are used. Use of this retardance affords a factor-of-1.5 improvement in signal-to-noise ratio over systems employing a quarter-wave plate. A geometric means of visualizing the optimization process is discussed, and the advantages of the use of additional measurements are investigated. No advantage of using retarder orientation angles spaced uniformly through 360 degree sign is found over repeated measurements made at the four retarder orientation angles. (c) 2000 Optical Society of America.

  7. Factors affecting social integration of noninstitutionalized mentally retarded adults.

    PubMed

    Reiter, S; Levi, A M

    1980-07-01

    The social integration of noninstitutionalized moderately and mildly mentally retarded young adults was investigated. A group of moderately and mildly retarded adults (study group) was compared with a group of borderline retarded (control group) adults on employability, behavior at work, social integration and social skills, personality, and self-concept. Findings indicated that the study group was less well integrated at work and in society than was the control group and showed lack of social skills. The retarded adults who had nonretarded friends showed better social-educational skills than did the other subjects. Findings suggest that even retarded individuals who grow up in the community need help in order to become socially independent. The existence of a special social club for retarded adults was found to fulfill the functions of a sheltered framework. Participants in the club showed more positive self-concepts; however, the club did not seem to prepare them for social integration in the general community. PMID:7446566

  8. Fire-retardant decorative inks for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Nir, Z.; Mikroyannidis, J. A.

    1985-01-01

    Commercial and experimental fire retardants were screened as potential fire retardants for acrylic printing inks used on aircraft interior sandwich panels. The fire retardants are selected according to their physical properties and their thermostabilities. A criterion for selecting a more stable fire retardant is established. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) are used to determine thermostabilities. Results show that the fire retardant formulations are more thermally stable than the acrylic ink control. It is determined that an ink formulation containing a brominated phenol and carboxy-terminated butadiene acrylonitrile which has been modified with a brominated polymeric additive (BPA), yields the highest limiting oxygen index (LOI) of all the compounds tested. All of the fire-retardant formulations have a higher oxygen index than the baseline acrylic ink.

  9. 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.

  10. Retrogradation of Waxy Rice Starch Gel in the Vicinity of the Glass Transition Temperature

    PubMed Central

    Charoenrein, Sanguansri; Udomrati, Sunsanee

    2013-01-01

    The retrogradation rate of waxy rice starch gel was investigated during storage at temperatures in the vicinity of the glass transition temperature of a maximally concentrated system (Tg′), as it was hypothesized that such temperatures might cause different effects on retrogradation. The Tg′ value of fully gelatinized waxy rice starch gel with 50% water content and the enthalpy of melting retrograded amylopectin in the gels were investigated using differential scanning calorimetry. Starch gels were frozen to −30°C and stored at 4, 0, −3, −5, and −8°C for 5 days. The results indicated that the Tg′ value of gelatinized starch gel annealed at −7°C for 15 min was −3.5°C. Waxy rice starch gels retrograded significantly when stored at 4°C with a decrease in the enthalpy of melting retrograded starch in samples stored for 5 days at −3, −5, and −8°C, respectively, perhaps due to the more rigid glass matrix and less molecular mobility facilitating starch chain recrystallization at temperatures below Tg′. This suggests that retardation of retrogradation of waxy rice starch gel can be achieved at temperature below Tg′. PMID:26904602

  11. Studies on the structure of actin gels using time correlation spectroscopy of fluorescent beads.

    PubMed Central

    Qian, H; Elson, E L; Frieden, C

    1992-01-01

    Fluorescence correlation spectroscopy (FCS) has been used to measure the diffusion of fluorescently labeled beads in solutions of polymerized actin or buffer. The results, obtained at actin concentrations of 1 mg/ml, show that small beads (0.09 micron in diameter) diffuse nearly as rapidly in the actin gel as in buffer, whereas the largest beads tested (0.5 micron in diameter) are immobilized. Measured autocorrelation times for motions of beads with intermediate sizes show that the diffusion is retarded (relative to buffer) and that the time behavior cannot be represented as a single diffusive process. In addition to the retarded diffusion observed over distances > 1 micron, 0.23-micron beads also show a faster motion over smaller distances. Based on the measured rate of this faster motion, we estimate that the beads may be constrained within a cage approximately 0.67 micron on a side, equal to a filament length of approximately 250 subunits. Fluorescence correlation spectroscopy measurements made in the same small spot (radius of 1.4 microns) of the gel vary over time. From the variations of both the autocorrelation functions and the mean fluorescence, we conclude that, corresponding to a spatial scale of 1.4 microns, the actin gel is a dynamic structure with slow rearrangement of the gel occurring over periods of 20-50 s at 21-22 degrees C. This rearrangement may result from local reorganization of the actin matrix. Data for the retardation of beads by the actin gel are consistent with a detailed theory of the diffusion of particles through solutions of rigid rods that have longitudinal diffusion coefficients much less than that of the particles (Ogston, A. G., B. N. Preston, and J. D. Wells. 1973. Proc. R. Soc. Lond. A. 333:297-316). PMID:1420920

  12. Spiritual and religious need of mentally retarded persons.

    PubMed

    Carder, M M

    1984-06-01

    Describes the special spiritual and religious needs of the mentally retarded, at the same time proclaiming the necessity of thinking of them firstly as persons. Gives specific illustrations of how the spiritual and religious needs of the mentally retarded may be met by peers, chaplains, and family members. Offers a personal testimony on how the mentally retarded can contribute to the growth and insight of the caregiver. PMID:10266989

  13. Comparison of Families of Children with Mental Retardation and Families of Children without Mental Retardation.

    ERIC Educational Resources Information Center

    Hodapp, Robert M.; Zigler, Edward

    1993-01-01

    This commentary on EC 605 926 states that families of children with severe mental retardation or autism have problems that might be considered "the same, only more so" compared to issues faced by families with nonhandicapped children, and therefore solutions might involve magnifications of solutions being suggested to help all parents. (JDD)

  14. Evaluation of Still Picture Telephone for Mentally Retarded Persons. Telematics and Mental Retardation.

    ERIC Educational Resources Information Center

    Brodin, Jane; Bjorck-Akesson, Eva

    This study examined the benefit of using a visual telecommunication system for Sweden's children and adults with mild to moderate mental retardation and speech difficulties. The Panasonic Image Communication Unit connects to standard modular telephones and includes a camera and monitor for the transfer of pictures. Units were placed in eight…

  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. Sexual Knowledge and Attitudes of Institutionalized and Noninstitutionalized Retarded Adolescents

    ERIC Educational Resources Information Center

    Hall, Judy E.; Morris, Helen L.

    1976-01-01

    Sixty-one noninstitutionalized and 61 institutionalized educable mentally retarded adolescents were psychometrically assessed on three measures: sexual knowledge, sexual attitudes, and self-concept. (Author)

  18. Rotatable broadband retarders for far infrared spectroscopic ellipsometry

    SciTech Connect

    Kang, T.D.; Carr, G.; Zhou, T.; Kotelyanskii, M.; Sirenko, A.A.

    2010-12-09

    Rotatable retarders have been developed for applications in spectroscopic, full Mueller Matrix ellipsometry in the far-IR spectral range. Several materials, such as silicon, KRS-5, and a commercial polymer plastic (TOPAS) have been utilized to achieve a fully adjustable retardation between 0{sup o} and 90{sup o}. Experimental characteristics of the rotatable retarders that utilize three- and four-bounce designs are compared with calculations. We discuss the effect of light focusing on the performance of these rotatable retarders. Broadband optical retarders are required for spectroscopic ellipsometry in its full Mueller matrix (MM) realization. Performance of the MM ellipsometer depends on the capability to produce substantially linearly-independent Stokes vectors for the light incident onto the sample. As has been shown, the errors in the measuredMMof the sample are proportional to the condition number of the 4 x 4 matrix composed of the Stokes vectors of four polarization states incident at the sample. It can be proven that it is impossible to cover the Poincare sphere with linearly-independent Stokes vectors by only changing the linear polarization at the input surface of a stationary retarder. As we will illustrate further in this paper, total coverage of the Poincare sphere is possible by rotating a tandem of a linear polarizer and a retarder with a retardation of 90{sup o}. It is this goal that we are trying to achieve in the retarder designs described in this paper.

  19. TG-FTIR characterization of flame retardant polyurethane foams materials

    NASA Astrophysics Data System (ADS)

    Liu, W.; Tang, Y.; Li, F.; Ge, X. G.; Zhang, Z. J.

    2016-07-01

    Dimethyl methylphosphonate (DMMP) and trichloroethyl phosphtate (TCEP) have been used to enhance the flame retardancy of polyurethane foams materials (PUF). Flame retardancy and thermal degradation of PUF samples have been investigated by the LOI tests and thermal analysis. The results indicate that the excellent flame retardancy can be achieved due to the presence of the flame retardant system containing DMMP and TCEP. TG-FTIR reveals that the addition of DMMP/TCEP can not only improve the thermal stability of PUF samples but can also affect the gaseous phase at high temperature.

  20. Fire-retardant decorative inks for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Nir, Z.; Mikroyannidis, J. A.; Kourtides, D. A.

    1984-01-01

    Commercial and experimental fire retardants were screened for possible use wiith acrylic printing inks on aircraft interior sandwich panels. The fire retardants were selected according to their physical properties and thermostabilities. Thermostabilities were determined by thermogravimetric analysis and differential scanning calorimetry. A criterion was then established for selecting the more stable agent. Results show that some of the bromine-containing fire retardants are more thermostable than the acrylic ink, alone, used as a control. Also, the bromine-containing fire retardants yield even better limiting oxygen index values when tested after adding carboxy-terminated butadiene acrylonitrile (CTBN) rubber.

  1. Teaching about Flame Retardants. A Joint Israeli-Dutch Project

    NASA Astrophysics Data System (ADS)

    Kesner, Miri; de Vos, Wobbe

    2001-01-01

    Flame retardants make interesting chemistry and moreover, the chemistry is highly relevant from an everyday life point of view. This article reports on a joint Israeli-Dutch project aimed at teaching the production, properties, and applications of some bromine-containing flame retardants, including their environmental aspects, in secondary education. We provide information on the nature of flame retardants in general and the mechanisms of flame retardation. In addition, we offer a complete pedagogical presentation of the topic, including the use of video and some simple laboratory experiments, that was developed and successfully implemented in both countries.

    Featured on the Cover

  2. Characterization of β -Glucosidase Produced by Aspergillus niger under Solid-State Fermentation and Partially Purified Using MANAE-Agarose.

    PubMed

    Baraldo Junior, Anderson; Borges, Diogo G; Tardioli, Paulo W; Farinas, Cristiane S

    2014-01-01

    β -Glucosidase (BGL) is a hydrolytic enzyme with specificity for a wide variety of glycoside substrates, being an enzyme with a large range of biotechnological applications. However, enzyme properties can be different depending both on the microorganism and the cultivation procedure employed. Therefore, in order to explore potential biocatalytical applications of novel enzymes, their characterization is essential. In this work, a BGL synthesized by a selected strain of Aspergillus niger cultivated under solid-state fermentation (SSF) was partially purified and fully characterized in terms of optimum pH, temperature, and thermostability. The single-step purification using MANAE-agarose in a chromatographic column yielded an enzyme solution with specific activity (17.1 IU/mg protein) adequate for the characterization procedures. Electrophoresis SDS-PAGE and size-exclusion chromatography analysis resulted in an estimated molecular mass of 60 kDa. Higher enzyme activities were found in the range between 40 and 65°C and between pH 4 and 5.5, indicating an interesting characteristic for application in the hydrolysis of lignocellulosic biomass for biofuels production. Thermostability studies of purified BGL resulted in half-lives at 37°C of 56.3 h and at 50°C of 5.4 h. These results provide support for further studies of this enzyme towards revealing its potential biotechnological applications. PMID:24940510

  3. Assaying Bcr-Abl kinase activity and inhibition in whole cell extracts by phosphorylation of substrates immobilized on agarose beads

    PubMed Central

    Wu, Ding; Nair-Gill, Evan; Sher, Dorie A.; Parker, Laurie L.; Campbell, Jennifer M.; Siddiqui, Mariah; Stock, Wendy; Kron, Stephen J.

    2015-01-01

    There is a current and increasing demand for simple, robust, nonradioactive assays of protein tyrosine kinase activity with applications for clinical diagnosis and high-throughput screening of potential molecularly targeted therapeutic agents. One significant challenge is to detect and measure the activity of specific kinases with key roles in cell signaling as an approach to distinguish normal cells from cancer cells and as a means of evaluating targeted drug efficacy and resistance in cancer cells. Here, we describe a method in which kinase substrates fused to glutathione-S-transferase and immobilized on glutathione agarose beads are phosphorylated, eluted, and then assayed to detect kinase activity. The activity of recombinant, purified c-Abl kinase or Bcr-Abl kinase in whole cell extracts can be detected with equivalent specificity, sensitivity, and reproducibility. Similarly, inhibition of recombinant c-Abl or Bcr-Abl in cells or cell extracts by imatinib mesylate and other Bcr-Abl targeted kinase inhibitors is readily assayed. This simple kinase assay is sufficiently straightforward and robust for use in clinical laboratories and is potentially adaptable to high-throughput assay formats. PMID:16236241

  4. First-in-Human Phase 1 Trial of Agarose Beads Containing Murine RENCA Cells in Advanced Solid Tumors

    PubMed Central

    Smith, Barry H.; Parikh, Tapan; Andrada, Zoe P.; Fahey, Thomas J.; Berman, Nathaniel; Wiles, Madeline; Nazarian, Angelica; Thomas, Joanne; Arreglado, Anna; Akahoho, Eugene; Wolf, David J.; Levine, Daniel M.; Parker, Thomas S.; Gazda, Lawrence S.; Ocean, Allyson J.

    2016-01-01

    PURPOSE Agarose macrobeads containing mouse renal adenocarcinoma cells (RMBs) release factors, suppressing the growth of cancer cells and prolonging survival in spontaneous or induced tumor animals, mediated, in part, by increased levels of myocyte-enhancing factor (MEF2D) via EGFR-and AKT-signaling pathways. The primary objective of this study was to determine the safety of RMBs in advanced, treatment-resistant metastatic cancers, and then its efficacy (survival), which is the secondary objective. METHODS Thirty-one patients underwent up to four intraperitoneal implantations of RMBs (8 or 16 macrobeads/kg) via laparoscopy in this single-arm trial (FDA BB-IND 10091; NCT 00283075). Serial physical examinations, laboratory testing, and PET-CT imaging were performed before and three months after each implant. RESULTS RMBs were well tolerated at both dose levels (mean 660.9 per implant). AEs were (Grade 1/2) with no treatment-related SAEs. CONCLUSION The data support the safety of RMB therapy in advanced-malignancy patients, and the preliminary evidence for their potential efficacy is encouraging. A Phase 2 efficacy trial is ongoing. PMID:27499645

  5. 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.

  6. In vitro estrogenicity of polybrominated flame retardants.

    PubMed

    Nakari, Tarja; Pessala, Piia

    2005-09-10

    Estrogenicity of five brominated flame retardants (BFRs), namely BDE-47, BDE-99, BDE-205, PBB-153 and technical Firemaster BP-6, were assessed by in vitro assays developed to detect chemicals with estrogenic properties. Recombinant yeast cells containing a human estrogen receptor gene failed to give any response to the chemicals tested. However, the positive control compound, estradiol-17beta, showed that the yeast cell assays had worked properly. The freshly separated fish hepatocyte assay based on the synthesis and secretion of vitellogenin from the isolated liver cells produced a clear dose-response curve in the presence of all tested flame retardants except Firemaster BP-6. The toxicity of the BFRs was detected by determining the cell ethoxyresorufin-O-deethylase activity (EROD). The BFRs tested induced hepatic EROD activity at low test concentrations, but started to inhibit activity at higher concentrations. The decreased detoxification capacity of the hepatocytes resulted in a decrease in the vitellogenin production of the cells. The capability of in vitro assays to detect estrogenic properties of chemicals seems to vary. Thus, further work is needed to understand the mechanisms responsible for these reactions. PMID:16024102

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. Inter-relationship among degree of mental retardation, living arrangements, and dental health in adults with mental retardation.

    PubMed

    Gabre, P; Gahnberg, L

    1997-01-01

    The aim of the present investigation was to study the inter-relationship among the degree of mental retardation, the way of living, and dental health in adults with mental retardation. One hundred and thirty-two adults between the ages of 21 and 40 years who were mentally retarded were examined on two occasions, one year apart. All subjects had had regular dental care for at least 10 years. The clinical examinations included bite-wing radiographs and were made by the same dentist. The degree of mental retardation was assessed by a professional psychologist. The results show that the degree of mental retardation as well as living arrangements are factors influencing the dental health of persons with mental retardation. Subjects who were mildly retarded had higher caries incidence and caries prevalence compared with subjects with moderate or severe mental retardation. From a preventive dental health perspective, special attention should be focused on subjects with mild mental retardation who are not living in institutions. PMID:9582703

  12. Optimization of Pulsed-field Gel Electrophoresis Procedure for Bacillus cereus.

    PubMed

    Zhang, Hui Juan; Pan, Zhuo; Wei, Jian Chun; Zhang, En Min; Cai, Hong; Liang, Xu Dong; Li, Wei

    2016-03-01

    In order to develop a rapid and reliable method for B. cereus genotyping, factors influencing PFGE results, including preparation of bacterial cells embedded in agarose, lysis of embedded cells, enzymatic digestion of intact genomic DNA, and electrophoresis parameters allowing for reproducible and meaningful DNA fragment separation, were controlled. Optimal cellular growth (Luria-Bertani agar plates for 12-18 h) and lysis conditions (4 h incubation with 500 µg/mL lysozyme) produced sharp bands on the gel. Restriction enzyme NotI was chosen as the most suitable. Twenty-two isolates were analyzed by NotI digestion, using three electrophoretic parameters (EPs). The EP-a was optimal for distinguishing between isolates. The optimized protocol could be completed within 40 h which is a significant improvement over the previous methods. PMID:27109136

  13. Mental Retardation. Fact Sheet = El Retraso Mental. Hojas Informativas Sobre Discapacidades.

    ERIC Educational Resources Information Center

    National Information Center for Children and Youth with Disabilities, Washington, DC.

    This fact sheet on mental retardation is written in both English and Spanish. It begins with a vignette of a 15-year-old boy with mental retardation. Mental retardation is briefly explained as are some causes of mental retardation. It notes that a diagnosis of mental retardation looks at two things: first, the ability of a person's brain to learn,…

  14. 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.

  15. Development and evaluation of in situ gel of pregabalin

    PubMed Central

    Madan, Jyotsana R; Adokar, Bhushan R; Dua, Kamal

    2015-01-01

    Aim and Background: Pregabalin (PRG), an analog of gamma-aminobutyric acid, reduces the release of many neurotransmitters, including glutamate, and noradrenaline. It is used for the treatment of epilepsy; simple and complex partial convulsion. The present research work aims to ensure a high drug absorption by retarding the advancement of PRG formulation through the gastrointestinal tract. The work aims to design a controlled release PRG formulation which is administered as liquid and further gels in the stomach and floats in gastric juice. Materials and Methods: In situ gelling formulations were prepared using sodium alginate, calcium chloride, sodium citrate, hydroxypropyl methylcellulose (HPMC) K100M, and sodium bicarbonate. The prepared formulations were evaluated for solution viscosity, drug content, in vitro gelling studies, gel strength, and in vitro drug release. The final formulation was optimized using a 32 full factorial design. Results: The formulation containing 2.5% w/v sodium alginate and 0.2% w/v calcium chloride were considered optimum since it showed minimum floating lag time (18 s), optimum viscosity (287.3 cps), and gel strength (4087.17 dyne/cm2). The optimized formulation follows Korsmeyer-Peppas kinetic model with n value 0.3767 representing Fickian diffusion mechanism of drug release. Conclusion: Floating in situ gelling system of PRG can be formulated using sodium alginate as a gelling polymer and calcium chloride as a complexing agent to control the drug release for about 12 h for the treatment of epilepsy. PMID:26682193

  16. Resonance Energy Transfer between protein and rhamnolipid capped ZnS quantum dots: Application in in-gel staining of proteins

    NASA Astrophysics Data System (ADS)

    Janakiraman, Narayanan; Mohan, Abhilash; Kannan, Ashwin; Pennathur, Gautam

    The interaction of proteins with quantum dots is an interesting field of research. These interactions occur at the nanoscale. We have probed the interaction of Bovine Serum Albumin (BSA) and Candida rugosa lipase (CRL) with rhamnolipid capped ZnS (RhlZnSQDs) using absorption and fluorescence spectroscopy. Optical studies on mixtures of RhlZnSQDs and proteins resulted in Förster's Resonance Energy Transfer (FRET) from proteins to QDs. This phenomenon has been exploited to detect proteins in agarose gel electrophoresis. The activity of the CRL was unaffected on the addition of QDs as revealed by zymography.

  17. 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

  18. DNA electrophoresis in tri-block copolymer gels--experiments and Brownian dynamics simulation

    NASA Astrophysics Data System (ADS)

    Wei, Ling; van Winkle, David H.

    2015-03-01

    The mobility of double-stranded DNA ladders in Pluronics®P105, P123 and F127, was measured by two-dimensional gel electrophoresis. Pluronics®are triblock copolymers which form gel-like phases of micelles arranged with cubic order at room temperature. A 10 base pair and a 25 base pair DNA ladder were used as samples in gel electrophoresis. The monotonically decreasing mobility with increasing length observed in the agarose separations is not observed in separations in Pluronics®. Rather, a complicated dependence of mobility on DNA length is observed, where mobility vs. length increases for short DNA molecules then decreases for longer molecules. There is also a variation of mobility with length correlated to the micelle diameter. Brownian dynamics simulations of a discrete wormlike chain model were performed to simulate short DNA molecules migrating in free solution and in a face-centered cubic matrix. By incorporating hydrodynamic interactions, the trend of simulated length-dependent mobility qualitatively agrees with experimental measurements.

  19. Root-Gel Interactions and the Root Waving Behavior of Arabidopsis1[w

    PubMed Central

    Thompson, Matthew V.; Holbrook, N. Michele

    2004-01-01

    Arabidopsis roots grown on inclined agarose gels exhibit a sinusoidal growth pattern known as root waving. While root waving has been attributed to both intrinsic factors (e.g. circumnutation) and growth responses to external signals such as gravity, the potential for physical interactions between the root and its substrate to influence the development of this complex phenotype has been generally ignored. Using a rotating stage microscope and time-lapse digital imaging, we show that (1) root tip mobility is impeded by the gel surface, (2) this impedance causes root tip deflections by amplifying curvature in the elongation zone in a way that is distinctly nontropic, and (3) root tip impedance is augmented by normal gravitropic pressure applied by the root tip against the gel surface. Thus, both lateral corrective bending near the root apex and root tip impedance could be due to different vector components of the same graviresponse. Furthermore, we speculate that coupling between root twisting and bending is a mechanical effect resulting from root tip impedance. PMID:15247406

  20. Detection of circular and linear herpesvirus DNA molecules in mammalian cells by gel electrophoresis.

    PubMed Central

    Gardella, T; Medveczky, P; Sairenji, T; Mulder, C

    1984-01-01

    A simple gel technique is described for the detection of large, covalently closed, circular DNA molecules in eucaryotic cells. The procedure is based on the electrophoretic technique of Eckhardt (T. Eckhardt, Plasmid 1:584-588, 1978) for detecting bacterial plasmids and has been modified for the detection of circular and linear extrachromosomal herpesvirus genomes in mammalian cells. Gentle lysis of suspended cells in the well of an agarose gel followed by high-voltage electrophoresis allows separation of extrachromosomal DNA from the bulk of cellular DNA. Circular viral DNA from cells which carry the genomes of Epstein-Barr virus, Herpesvirus saimiri, and Herpesvirus ateles can be detected in these gels as sharp bands which comigrate with bacterial plasmid DNA of 208 kilobases. Epstein-Barr virus producer cell lines also show a sharp band of linear 160-kilobase DNA. The kinetics of the appearance of this linear band after induction of viral replication after temperature shift parallels the known kinetics of Epstein-Barr virus production in these cell lines. Hybridization of DNA after transfer to filters shows that the circular and linear DNA bands are virus specific and that as little as 0.25 Epstein-Barr virus genome per cell can be detected. The technique is simple, rapid, and sensitive and requires relatively low amounts of cells (0.5 X 10(6) to 2.5 X 10(6)). Images PMID:6321792

  1. Agarose film liquid phase microextraction combined with gas chromatography-mass spectrometry for the determination of polycyclic aromatic hydrocarbons in water.

    PubMed

    Sanagi, Mohd Marsin; Loh, Saw Hong; Wan Ibrahim, Wan Aini; Hasan, Mohamed Noor

    2012-11-01

    Agarose film liquid phase microextraction (AF-LPME) procedure for the extraction and preconcentration of polycyclic aromatic hydrocarbons (PAHs) in water has been investigated. Agarose film was used for the first time as an interface between donor and acceptor phases in liquid phase microextraction which allowed for selective extraction of the analytes prior to gas chromatography-mass spectrometry. Using 1-octanol as acceptor phase, high enrichment factors in the range of 57-106 for the targeted analytes (fluorene, phenanthrene, fluoranthene and pyrene) were achieved. Under the optimum extraction conditions, the method showed good linearity in the range of 0.1-200 μgL(-1), good correlation coefficients in the range of 0.9963-0.9999, acceptable reproducibility (RSD 6.1-9.2%, n=3), low limits of detection (0.01-0.04 μgL(-1)) and satisfactory relative recoveries (92.9-104.7%). As the AF-LPME device was non-expensive, reuse or recycle of the film was not required, thus eliminating the possibility of analytes carry-over between runs. The AF-LPME technique is environment-friendly and compatible with the green chemistry concept as agarose is biodegradable polysaccharide extracted from seaweed and the procedure requires small volume of organic solvent and generates little waste. The validated method was successfully applied to the analysis of the four analytes in river water samples. PMID:23021646

  2. Facile synthesis of nano-sized agarose based amino acid-Its pH-dependent protein-like behavior and interactions with bovine serum albumin.

    PubMed

    Chudasama, Nishith A; Siddhanta, A K

    2015-11-19

    In a facile synthesis agarose was amphoterically functionalized to afford nano-sized agarose amino acids, aminoagarose succinate half-esters (AAE) containing one pendant carboxyl group. Nano-sized AAEs (<10 nm; DLS) were characterized and they had three various degrees of substitution [overall DSs 0.88, 0.89 and 0.96], both the amino and half-ester groups were placed on C-6 positions of the 1,3 beta-d-galactopyranose moieties of agarose backbone ((13)C NMR). AAEs performed like large protein molecules exhibiting pH-responsive structural variations (optical rotatory dispersion), presenting a mixed solubility pattern like random coil (soluble) and aggregate (precipitation) formations. Circular dichroism studies showed their pH-dependent associative interactions with bovine serum albumin, which indicated complexation at acidic and basic pHs, and decomplexation at pH 6.8 with AAE (DS 0.96). Thus, these nano-sized AAE based systems may be of potential utility in the domains demanding the merits of preferential protein bindings e.g. pH-responsive cationic/anionic drug carrier, separations or chiral sensing applications. PMID:26413976

  3. 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.

  4. 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

  5. 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.

  6. Further Evidence for Cognitive Inertia of Persons with Mental Retardation.

    ERIC Educational Resources Information Center

    Ellis, Norman R.; Dulaney, Cynthia L.

    1991-01-01

    Forty young adults with mental retardation (MR) were compared to 40 young adults without mental retardation in tests examining postpractice interference effects in naming colors of Stroop words. The study concluded that practice developed automatized reading suppression responses which held greater cognitive inertia for longer periods among MR…

  7. Labeling, Rehearsal, and Short-Term Memory in Retarded Children

    ERIC Educational Resources Information Center

    Hagen, John W.; And Others

    1974-01-01

    A short-term memory task was used to explore the effects of verbal labeling and rehearsal on serial-position recall in mildly retarded 9-to 11-year-old children. Results support the view that verbal skills affect recall in mildly retarded children similarly to normal children. (Author/SDH)

  8. Classification of Residential Facilities for Mentally Retarded People. Brief #24.

    ERIC Educational Resources Information Center

    Hill, B. K.; Lakin, K. C.

    This paper describes the development of a taxonomy of residential facilities for mentally retarded people based on program model, size, and operation. Data are presented on the use of the classification system in a national survey of 15,633 residential facilities for mentally retarded persons in the United States. Program models are defined…

  9. Burnout in Teachers of Retarded and Nonretarded Children.

    ERIC Educational Resources Information Center

    Beck, Cynthia L.; Gargiulo, Richard M.

    1983-01-01

    When teachers of moderately retarded, mildly retarded, and nonretarded students were asked to assess their own degree of burnout, special education teachers reported fewer and weaker feelings of inadequateness than did regular classroom teachers. Possible reasons for this finding and suggestions for stress reduction are given. (Authors/PP)

  10. Carbamazepine-Induced Hyponatremia in Patients with Mental Retardation.

    ERIC Educational Resources Information Center

    Kastner, Ted; And Others

    1992-01-01

    This study of 40 patients with mental retardation receiving carbamazepine found hyponatremia in only 5 percent of these patients and found a statistically, but not clinically, significant decrease in serum sodium levels in patients receiving anticonvulsant polytherapy. Results support the use of this drug with patients with mental retardation and…

  11. Building America Top Innovations 2012: Vapor Retarder Classification

    SciTech Connect

    none,

    2013-01-01

    This Building America Top Innovations profile describes research in vapor retarders. Since 2006 the IRC has permitted Class III vapor retarders like latex paint (see list above) in all climate zones under certain conditions thanks to research by Building America teams.

  12. Perceptual-Motor Attributes of Mentally Retarded Youth.

    ERIC Educational Resources Information Center

    Cratty, Bryant J.

    To evaluate six perceptual-motor attributes of trainable and educable mentally retarded children, a battery of tests was constructed which included body perception, gross agility, balance, locomotor ability, throwing, and tracking; 83 retarded subjects provided reliability data, and their scores, with those of 120 additional subjects, provided…

  13. 45 CFR 1308.10 - Eligibility criteria: Mental retardation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... DISABILITIES Health Services Performance Standards § 1308.10 Eligibility criteria: Mental retardation. (a) A... 45 Public Welfare 4 2012-10-01 2012-10-01 false Eligibility criteria: Mental retardation. 1308.10... DEVELOPMENT SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES THE ADMINISTRATION FOR CHILDREN, YOUTH...

  14. Characteristics of the Conditional Reasoning of Educable Retardates.

    ERIC Educational Resources Information Center

    Antonak, Richard F.; Roberge, James J.

    1978-01-01

    Pictorial conditional reasoning test items which were varied according to principle of inference and type of content were administered to three groups of educably mentally retarded children. Results revealed that retardates' reasoning strategies were congruent with those reported for younger normals in previous studies. (Author/JKS)

  15. Mental Retardation. Selected Articles from the Rehabilitation Record.

    ERIC Educational Resources Information Center

    Rehabilitation Services Administration (DHEW), Washington, DC.

    Presented are six articles on residential living, vocational education, employment recreation, deinstitutionalization, and workshop experience of mentally retarded children and adults. K. Grunewald discusses the planning of housing for five- to eight person groups of retarded children and adults in varying kinds of residential facilities in Sweden…

  16. Behavioral Treatment of Aggression in the Mentally Retarded: A Review.

    ERIC Educational Resources Information Center

    Feldstein, Jerome H.

    The paper reviews 34 behavioral treatment studies (1967-1983) examining reduction of aggressive behavior in mentally retarded people. Research reviewed was limited to treatment of physically aggressive responses such as hits, kicks, bites, chokes, scratches, and throwing objects by persons designated as mentally retarded. Among results reported…

  17. Nutrition and Mental Retardation. An Annotated Bibliography, 1964-1970.

    ERIC Educational Resources Information Center

    Springer, Ninfa Saturnino

    This annotated bibliography is primarily organized for nutritionists. It presents selected articles published from 1964 to the present. All aspects of nutrition in mental retardation are covered excepting inborn errors of metabolism. Sections are included on: (1) nutrition, birthweight, and mental retardation; (2) nutrition, growth, and mental…

  18. Arizona's Comprehensive Plan to Help the Mentally Retarded.

    ERIC Educational Resources Information Center

    Arizona State Dept. of Health, Phoenix. Mental Retardation Section.

    To help combat mental retardation, 136 recommendations are made for the following: establishment by statute of a division of mental retardation, an advisory council, and a coordinating council of agencies; changes in laws governing the Arizona Children's Colony, additional public school legislation, and a study of civil and criminal law; immediate…

  19. Recreation for the Mentally Retarded: A Handbook for Ward Personnel.

    ERIC Educational Resources Information Center

    Southern Regional Education Board, Atlanta, GA.

    Designed primarily for use by ward personnel in residential facilities for the mentally retarded, the manual presents an overview of recreational services. Four papers introduce the importance of recreation and consider approaches for its provision: "Why Recreation?" (W. Lawler); "The Role of the Attendant in Providing Recreation for the Retarded"…

  20. Association between the Diagnosis of Mental Retardation and Socioeconomic Factors.

    ERIC Educational Resources Information Center

    Slone, Michelle; Durrheim, Kevin; Lachman, Peter; Kaminer, Debra

    1998-01-01

    An examination of clinical data from the regional hospital in Cape Town, South Africa, over four years for 538 children with a diagnosis of mental retardation found mild mental retardation referrals were underrepresented in low socioeconomic areas and that paramedical agencies were the primary referral source in these areas. (Author/CR)

  1. Development of the Fear Survey for Adults with Mental Retardation

    ERIC Educational Resources Information Center

    Ramirez, Sylvia Z.; Lukenbill, James F.

    2007-01-01

    This paper describes the development of the fear survey for adults with mental retardation (FSAMR) and provides initial evidence of its psychometric properties. The FSAMR was designed to be sensitive to the assessment needs of individuals with mental retardation. The items were developed through open-ended interviews, a review of existing…

  2. COGNITIVE TRAINING WITH RETARDED CHILDREN, I. FINAL REPORT.

    ERIC Educational Resources Information Center

    CORTER, HAROLD M.; MCKINNEY, JAMES D.

    THE MAJOR PURPOSE OF THIS RESEARCH WAS TO DETERMINE WHETHER TRAINING IN SPECIFIC COGNITIVE PROCESSES IS EFFECTIVE IN INCREASING THE COGNITIVE FUNCTIONING OF RETARDED CHILDREN. IN PHASE I OF THE PROJECT, 51 EDUCABLE RETARDED AND 18 NORMAL SUBJECTS RECEIVED A 20-DAY PROGRAM IN SIMILARITIES-DIFFERENCES CONCEPT FORMATION AND WERE COMPARED WITH 42…

  3. Flame retardant antibacterial cotton high-loft nonwoven fabrics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flame retardant treated gray cotton fibers were blended with antibacterial treated gray cotton fibers and polyester/polyester sheath/core bicomponent fibers to form high-loft fabrics. The high flame retardancy (FR) and antibacterial property of these high lofts were evaluated by limiting oxygen inde...

  4. Adaptive Behavior Malingering in Legal Claims of Mental Retardation

    ERIC Educational Resources Information Center

    Kadlubek, Renee Marie

    2012-01-01

    In 2002, the Supreme Court ruled that it is unconstitutional to put people with mental retardation to death for capital crimes ("Atkins v. Virginia," 2002). Justice Scalia dissented, suggesting that mental retardation is a condition easy to feign. The current study examined whether participants provided with the definition of mental…

  5. Qualitative Differences in the Structure of Intelligence of Retarded Children.

    ERIC Educational Resources Information Center

    Wilson, Sheryl L.; Cleaves, Wallace T.

    To examine whether or not retarded individuals have the same structure of intelligence as normal IQ individuals, test scores from the Wechsler Intelligence Scale for Children-Revised (WISC-R), Reitan's Trail Making Test (TMT), and Beery's Developmental Test of Visual Motor Integration (VMI) for both a mildly retarded and normal IQ population of…

  6. Eyewitness Memory and Suggestibility in Children with Mental Retardation.

    ERIC Educational Resources Information Center

    Henry, Lucy A.; Gudjonsson, Gisli H.

    1999-01-01

    A study compared how well 31 children (ages 11-12) with mental retardation, 19 age-matched (CA) children, and 21 mental-age (MA) matched children were able to recall a staged event one day later. Children with mental retardation were more suggestible in response to closed misleading questions than were CA children. (Contains references.)…

  7. Family Problem-Solving with Children Who Have Mental Retardation

    ERIC Educational Resources Information Center

    Floyd, Frank J; Harter, Kristina S. M.; Costigan, Catherine L.

    2004-01-01

    Problem-solving discussions were observed within families of children with mental retardation and multiple comparison groups (total N = 162 families). As expected, parents were more persistent and directive with their children who had mental retardation, but they also avoided negative exchanges with these children. These patterns did not spillover…

  8. Psychopharmacology and Mental Retardation: A 10 Year Review (1990- 1999).

    ERIC Educational Resources Information Center

    Matson, Johnny L.; Bamburg, Jay W.; Mayville, Erik A.; Pinkston, Jim; Bielecki, Joanne; Kuhn, David; Smalls, Yemonja; Logan, James R.

    2000-01-01

    Review of the literature on psychopharmacology and mental retardation from 1990-1999 found most studies had major methodological flaws. Also, most drug administrations were not based in science, were not evaluated appropriately, and generally did not follow best practices for treatment of persons with mental retardation. A table lists the studies…

  9. Cone calorimeter evaluation of two flame retardant cotton fabrics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Unbleached (grey) cotton needle punched nonwoven (NW) fabrics with 12.5% polypropylene scrim were treated with two phosphate-nitrogen based fire-retardant (FR) formulations, SRRC-1 and SRRC-2. The SRRC-1 formulation contains diammonium phosphate as the flame retardant chemical along with urea and d...

  10. Newborn Screening To Prevent Mental Retardation. The Arc Q & A.

    ERIC Educational Resources Information Center

    Arc, Arlington, TX.

    This information fact sheet on screening newborns to prevent mental retardation defines newborn screening and outlines how screening is performed. It discusses the six most common disorders resulting in mental retardation for which states most commonly screen. These include phenylketonuria, congenital hypothyroidism, galactosemia, maple syrup…

  11. Serial Memory Span Thresholds of Normal and Mentally Retarded Children

    ERIC Educational Resources Information Center

    Baumeister, Alfred A.

    1974-01-01

    Educable mental retardates and normal grade school students were presented seven classes of materials in both visual and auditory modalities for the determination of immediate memory span thresholds. Major conclusions included auditory presentation produces higher thresholds than visual, and retarded children may employ different processing…

  12. Programs for Preventing the Causes of Mental Retardation.

    ERIC Educational Resources Information Center

    Oliphant, Peter S.; And Others

    This monograph, which reports findings from the New Jersey Governor's Council on the Prevention of Mental Retardation, discusses the scope of mental retardation (MR), its causes, identification of people at risk, and prevention methods. The Council cites several cost-effective prevention programs, such as vaccination programs and prenatal care…

  13. Implicit Learning in Children and Adolescents with Mental Retardation.

    ERIC Educational Resources Information Center

    Vinter, Annie; Detable, Christelle

    2003-01-01

    A study compared the implicit learning of 58 children (ages 7-14) with mental retardation and 53 controls (ages 3-8). Individuals with mental retardation modified their behavior after an implicit training procedure similar to the controls. The effect of implicit learning did not vary as a function of IQ or age. (Contains references.) (Author/CR)

  14. Flame retardant properties of triazine phosphonates derivative with cotton fabric

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The flame retardant behavior of a cotton fabric treated with phosphorus-nitrogen containing triazine compound was evaluated. It was found that cyanuric chloride (2,4,6-trichloro-1,3,5-triazine) is an excellent starting material for the preparation of phosphonates flame retardants that interacts wel...

  15. CEC Selected Convention Papers; Annual International Convention: Mental Retardation.

    ERIC Educational Resources Information Center

    Council for Exceptional Children, Arlington, VA.

    The following articles on mental retardation are provided: translating research findings into classroom activity; camping programs; a measurement device for educable mentally retarded adolescents on their self-concept as a worker; an investigation of the Doman-Delacato Theory in a trainable program in the public schools; and problems of sex…

  16. Pre-Professional Training in Mental Retardation. Final Report.

    ERIC Educational Resources Information Center

    Lown, Irving C., Jr.

    To interest students in mental retardation health services careers, 10 eligible prebaccalaureate students were selected to participate in a 10-week summer training program. The first 2 weeks involved orientation to informational and training aspects of mental retardation and exposure to the health services related disciplines of recreational and…

  17. Communication Problems in Mental Retardation: Diagnosis and Management.

    ERIC Educational Resources Information Center

    Lillywhite, Herold S.; Bradley, Doris P.

    Discussed are the problems of communication in mental retardation with an introductory background and definition of this problem, including the etiological factors and general characteristics. A presentation of diagnostic methods leads into discussions of the problem of medical-dental management and educational management of the retarded child.…

  18. Novel phosphonates triazine derivative as economic flame retardant for cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorous-containing flame retardants are widely used in standard and engineering plastics, polyurethane foams, thermosets, coatings, and textiles. Organophosphorous flame retardants have been known to be more effective when used in conjunction with nitrogen-containing systems. Their mixture produ...

  19. IN VITRO DERMAL ABSORPTION OF FLAME RETARDANT CHEMICALS

    EPA Science Inventory

    ABSTRACT
    The use of flame retardant chemicals in furniture fabric could pose a potential health risk to consumers from dermal absorption of these compounds. The objective of this study was to examine the in vitro dermal absorption of two flame retardant chemicals, [14C]-d...

  20. Defining Mental Retardation: A Matter of Life or Death

    ERIC Educational Resources Information Center

    Lichten, William; Simon, Elliot W.

    2007-01-01

    Because persons with mental retardation cannot be executed for murder, the diagnosis becomes a life and death matter. The American Association on Mental Retardation (now the American Association on Intellectual and Developmental Disabilities) and other associations agree that IQ alone is an insufficient criterion and adaptive functioning also…

  1. 45 CFR 1308.10 - Eligibility criteria: Mental retardation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... DISABILITIES Health Services Performance Standards § 1308.10 Eligibility criteria: Mental retardation. (a) A child is classified as mentally retarded who exhibits significantly sub-average intellectual functioning and exhibits deficits in adaptive behavior which adversely affect learning. Adaptive behavior...

  2. PUBLIC PROVISION FOR THE MENTALLY RETARDED IN THE UNITED STATES.

    ERIC Educational Resources Information Center

    BEST, HARRY

    WRITTEN FROM THE STANDPOINT OF THE SOCIOLOGIST OR SOCIAL SCIENTIST, THIS BOOK REPORTS DATA OBTAINED FROM STATISTICAL RESEARCH ON MENTAL RETARDATES. ITS CHIEF PURPOSE IS THE SCIENTIFIC STUDY OF THE MENTALLY RETARDED AND PROVISIONS MADE FOR THEM IN THE UNITED STATES. DISCUSSION OF THE GENERAL CONDITION COVERS DEFINITION AND CLASSIFICATION, ETIOLOGY,…

  3. Estate Planning for Retarded Persons and Their Families.

    ERIC Educational Resources Information Center

    Fruge, Don L.; Green, Karen O.

    Intended for parents and legal guardians of mentally retarded persons, the manual provides guidelines for estate planning. An overview of definitions, causes, and prevalence factors in retardation is followed by reviews of the major financial assistance governmental programs such as Medicare, and Supplemental Security Income, and of legal…

  4. Ocular findings among mentally retarded children in Finland.

    PubMed

    Tuppurainen, K

    1983-08-01

    The distribution of refractive errors, astigmatism, anisometropia, visual acuity and organic ophthalmic diseases were determined among 149 Finnish mentally retarded (IQ less than 70) children, aged 9-10 years. The case group was classified in 3 categories according to the degree of mental retardation. The control group (n = 100) was selected by random sampling. PMID:6637425

  5. Defining Mental Retardation and Ensuring Access to the General Curriculum.

    ERIC Educational Resources Information Center

    Wehmeyer, Michael L.

    2003-01-01

    Discussion of trends in the American Association on Mental Retardation's definition of mental retardation notes a shift toward a support paradigm and a definition stressing the interaction between a person's independent functioning and the various contexts of the person's life. The current definition is seen to promote greater access to the…

  6. School Behavior Problems of Mentally Retarded and Normal Females.

    ERIC Educational Resources Information Center

    Cullinan, Douglas; And Others

    1983-01-01

    Female elementary, middle, and high school students (N=146) identified as educable mentally retarded were rated on the Quay-Peterson Behavior Problem Checklist by their teachers. Normal females were also rated for comparison. Analyses indicated that mentally retarded females exceeded normal females on the Conduct Disorder, Personality Problem, and…

  7. Theories on Criminality and Mental Retardation Project CAMIO, Volume 2.

    ERIC Educational Resources Information Center

    Haskins, Jimmy R.; Friel, Charles M.

    This historical review of theories on criminality and mental retardation is part of Project CAMIO (Correctional Administration and the Mentally Incompetent Offender), a Texas study to determine the incidence of criminal incarceration of the mentally retarded (MR) and to identify laws, procedures, and practices which affect the prosecution and…

  8. 38 CFR 4.127 - Mental retardation and personality disorders.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... personality disorders. 4.127 Section 4.127 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS... and personality disorders. Mental retardation and personality disorders are not diseases or injuries... superimposed upon mental retardation or a personality disorder may be service-connected. (Authority: 38...

  9. 38 CFR 4.127 - Mental retardation and personality disorders.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... personality disorders. 4.127 Section 4.127 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS... and personality disorders. Mental retardation and personality disorders are not diseases or injuries... superimposed upon mental retardation or a personality disorder may be service-connected. (Authority: 38...

  10. 38 CFR 4.127 - Mental retardation and personality disorders.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... personality disorders. 4.127 Section 4.127 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS... and personality disorders. Mental retardation and personality disorders are not diseases or injuries... superimposed upon mental retardation or a personality disorder may be service-connected. (Authority: 38...

  11. 38 CFR 4.127 - Mental retardation and personality disorders.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... personality disorders. 4.127 Section 4.127 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS... and personality disorders. Mental retardation and personality disorders are not diseases or injuries... superimposed upon mental retardation or a personality disorder may be service-connected. (Authority: 38...

  12. 38 CFR 4.127 - Mental retardation and personality disorders.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... personality disorders. 4.127 Section 4.127 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS... and personality disorders. Mental retardation and personality disorders are not diseases or injuries... superimposed upon mental retardation or a personality disorder may be service-connected. (Authority: 38...

  13. Muscle Fatigue during Intermittent Exercise in Individuals with Mental Retardation

    ERIC Educational Resources Information Center

    Zafeiridis, Andreas; Giagazoglou, Paraskevi; Dipla, Konstantina; Salonikidis, Konstantinos; Karra, Chrisanthi; Kellis, Eleftherios

    2010-01-01

    This study examined fatigue profile during intermittent exercise in 10 men with mild to moderate mental retardation (MR) and 10 men without mental retardation (C). They performed 4 x 30 s maximal knee extensions and flexions with 1-min rest on an isokinetic dynamometer. Peak torque of flexors (PTFL) and extensors (PTEX), total work (TW), and…

  14. TERMINOLOGY AND CONCEPTS IN APPRAISING THE MENTALLY RETARDED.

    ERIC Educational Resources Information Center

    LORGE, IRVING; AND OTHERS

    THE OBJECTIVE OF THIS STUDY WAS TO MINIMIZE THE VARIABILITY IN LEGAL AND EDUCATIONAL CLASSIFICATION OF THE MENTALLY RETARDED. A SYSTEMATIC REVIEW WAS MADE OF THE SEMANTIC VARIATIONS IN THE DEFINITION OF THE MENTALLY RETARDED IN TERMS OF FUNCTIONAL ADEQUACY FOR EDUCATION, TRAINING, OR CUSTODIAL CARE. THE METHOD INVOLVED THE REVIEW OF STATUTES AND…

  15. A Practical Guide for Teaching the Mentally Retarded to Swim.

    ERIC Educational Resources Information Center

    American Association for Health, Physical Education, and Recreation, Washington, DC.

    A guide for teaching the retarded to swim begins with a general discussion of retardation, the need for individualization, and staff qualifications. Factors discussed in program organization and administration include community agencies, staff training, examples of records and forms, and first aid procedures. Suggested methods consider perceptual…

  16. Physical Trauma as an Etiological Agent in Mental Retardation.

    ERIC Educational Resources Information Center

    Angle, Carol R., Ed.; Bering, Edgar A., Jr., Ed.

    The conference on Physical Trauma as a Cause of Mental Retardation dealt with two major areas of etiological concern - postnatal and perinatal trauma. Following two introductory statements on the problem of and issues related to mental retardation (MR) after early trauma to the brain, five papers on the epidemiology of head trauma cover…

  17. Highly durable and efficient quantum dot-sensitized solar cells based on oligomer gel electrolytes.

    PubMed

    Kim, Heejin; Hwang, Insung; Yong, Kijung

    2014-07-23

    For stable quantum dot-sensitized solar cells, an oligomer-contained gel electrolyte was employed with a carbon-based counter electrode and a hierarchically shelled ZnO photoelectrode. Poly(ethylene glycol) dimethyl-ether (PEGDME) was added to the polysulfide electrolyte to enhance the stability of the methanol-based electrolyte. In addition, the nanocomposite gel electrolyte with fumed silica was used, which provided a solid three-dimensional network. A quantum-dot-modified ZnO nanowire photoanode enhanced the visible light harvesting, and a Pt/CNT-RGO counter electrode increased the catalytic activity. The oligomer gel electrolyte prevented the liquid electrolyte from leaking, and the carbon-based counter electrode retarded chemical poisoning at the counter electrode. The optimized cell exhibited 5.45% photoelectric conversion efficiency with long-term stability demonstrated over 5000 s operation time. PMID:24987930

  18. Cytogenetic Findings in Mentally Retarded Iranian Patients

    PubMed Central

    Nasiri, F; Mahjoubi, F; Manouchehry, F; Razazian, F; Mortezapour, F; Rahnama, M

    2012-01-01

    We conducted a cytogenetic study on 865 individuals with idiopathic mental retardation (MR) who were admitted to the Cytogenetics Department of the Iran Blood Transfusion Organisation (IBTO) Research Centre, Tehran, Iran; these were performed on blood samples using conventional staining methods. Chromosome anomalies were identified in 205 of the patients (23.6%). The majority were Down’s syndrome cases (n = 138). In 33 males, a positive fragile X anomaly was found. The remainder (n = 34) had other chromosomal abnormalities including structural chromosome aberrations (n = 23), marker chromosomes with an unknown origin (n = 3), sex chromosome aneuploidy (n = 6) and trisomy 18 (n = 2). The contribution of chromosome aberrations to the cause of MR in this group of patients is discussed. PMID:24052729

  19. A mentally retarded patient with schizophrenia.

    PubMed

    Rabia, K; Khoo, Em

    2008-01-01

    Schizophrenia is one of the most incapacitating forms of mental disorder that runs a chronic and relapsing course. It typically starts in adolescence or early adulthood and can be life-long. It is more common in people with learning disabilities than in the general population. Its prodromal features include depression, anxiety, suspiciousness, social isolation and bizarre behaviour. It may result in significant functional, social and economic impairments. The care of patients with schizophrenia places a considerable burden on all carers including patient's family, health and social services. Treatment includes pharmacotherapy and psychosocial interventions. In this case report we describe a thirteen-year-old patient with schizophrenia who has a background history of mental retardation. PMID:25606140

  20. 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

  1. Environmental monitoring of brominated flame retardants

    NASA Astrophysics Data System (ADS)

    Vagula, Mary C.; Kubeldis, Nathan; Nelatury, Charles F.

    2011-06-01

    Brominated flame retardants (BFRs) are synthetic organobromide compounds which inhibit ignition and combustion processes. Because of their immense ability to retard fire and save life and property, they have been extensively used in many products such as TVs, computers, foam, plastics etc. The five major classes of BFRs are tetrabromobisphenol-A (TBBPA), hexabromocyclododecane (HBCD), pentabromodiphenyl ether, octabromodiphenyl ether, and decabromodiphenyl ether. The last three are also commonly called PBDEs. BDE-85 and BDE-209 are the two prominent congeners of PBDEs and this study reports the adverse effects of these congeners in rodents. Exposure of rat sciatic nerves to 5 μg/mL and 20 μg/mL of BDE-85 and BDE-209 respectively lead to significant, concentration dependent reduction in nerve conduction function. Glucose absorption in the rat intestinal segments exposed to 5 μg/mL of BDE-85 and BDE-209 was significantly reduced for both the compounds tested. Lastly, mice when exposed to 0.25 mg/kg body weight for four days showed a disruption in oxidant and antioxidant equilibrium. The tissues namely liver and brain have shown increase in the levels of lipid hydroperoxides indicating oxidative stress. Moreover, all the protective enzymes namely superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase, and glutathione S transferase (GST) have shown tissue specific alterations indicating the induction of damaging oxidative stress and setting in of lipid peroxidation in exposed animals. The results indicate monitoring of PBDEs in the environment is essential because levels as low as 5 μg/mL and 0.25 mg/kg body weight were able to cause damage to the functions of rodents.

  2. Optimization of retardance for a complete Stokes polarimeter

    SciTech Connect

    Sabatke, D.S.; Descour, M.R.; Dereniak, E.L.; Sweatt, W.C.; Kemme, S.A.; Phipps, G.S.

    2000-01-13

    The authors present two figures of merit based on singular value decomposition which can be used to assess the noise immunity of a complete Stokes polarimeter. These are used to optimize a polarimeter consisting of a rotatable retarder and fixed polarizer. A retardance of 132{degree} (approximately three eights wave) and retarder orientation angles of {+-}51.7{degree} and {+-}15.1{degree} are found to be optimal when four measurements are used. Use of this retardance affords a factor of 1.5 improvement in signal-to-noise ratio over systems employing a quarter wave plate. A geometric means of visualizing the optimization process is discussed, and the advantages of the use of additional measurements are investigated. No advantage of using retarder orientation angles spaced uniformly through 360{degree} is found over repeated measurements made at the four angles given previously.

  3. Highly accurate spectral retardance characterization of a liquid crystal retarder including Fabry-Perot interference effects

    SciTech Connect

    Vargas, Asticio; Mar Sánchez-López, María del; García-Martínez, Pascuala; Arias, Julia; Moreno, Ignacio

    2014-01-21

    Multiple-beam Fabry-Perot (FP) interferences occur in liquid crystal retarders (LCR) devoid of an antireflective coating. In this work, a highly accurate method to obtain the spectral retardance of such devices is presented. On the basis of a simple model of the LCR that includes FP effects and by using a voltage transfer function, we show how the FP features in the transmission spectrum can be used to accurately retrieve the ordinary and extraordinary spectral phase delays, and the voltage dependence of the latter. As a consequence, the modulation characteristics of the device are fully determined with high accuracy by means of a few off-state physical parameters which are wavelength-dependent, and a single voltage transfer function that is valid within the spectral range of characterization.

  4. High seeding density of human chondrocytes in agarose produces tissue-engineered cartilage approaching native mechanical and biochemical properties.

    PubMed

    Cigan, Alexander D; Roach, Brendan L; Nims, Robert J; Tan, Andrea R; Albro, Michael B; Stoker, Aaron M; Cook, James L; Vunjak-Novakovic, Gordana; Hung, Clark T; Ateshian, Gerard A

    2016-06-14

    Animal cells have served as highly controllable model systems for furthering cartilage tissue engineering practices in pursuit of treating osteoarthritis. Although successful strategies for animal cells must ultimately be adapted to human cells to be clinically relevant, human chondrocytes are rarely employed in such studies. In this study, we evaluated the applicability of culture techniques established for juvenile bovine and adult canine chondrocytes to human chondrocytes obtained from fresh or expired osteochondral allografts. Human chondrocytes were expanded and encapsulated in 2% agarose scaffolds measuring ∅3-4mm×2.3mm, with cell seeding densities ranging from 15 to 90×10(6)cells/mL. Subsets of constructs were subjected to transient or sustained TGF-β treatment, or provided channels to enhance nutrient transport. Human cartilaginous constructs physically resembled native human cartilage, and reached compressive Young's moduli of up to ~250kPa (corresponding to the low end of ranges reported for native knee cartilage), dynamic moduli of ~950kPa (0.01Hz), and contained 5.7% wet weight (%/ww) of glycosaminoglycans (≥ native levels) and 1.5%/ww collagen. We found that the initial seeding density had pronounced effects on tissue outcomes, with high cell seeding densities significantly increasing nearly all measured properties. Transient TGF-β treatment was ineffective for adult human cells, and tissue construct properties plateaued or declined beyond 28 days of culture. Finally, nutrient channels improved construct mechanical properties, presumably due to enhanced rates of mass transport. These results demonstrate that our previously established culture system can be successfully translated to human chondrocytes. PMID:27198889

  5. Treatment of agarose–agarose RENCA macrobeads with docetaxel selects for OCT4+ cells with tumor-initiating capability

    PubMed Central

    Gazda, Lawrence S; Martis, Prithy C; Laramore, Melissa A; Bautista, Melissa A; Dudley, Atira; Vinerean, Horatiu V; Smith, Barry H

    2013-01-01

    The cancer stem cell (CSC) theory depicts such cells as having the capacity to produce both identical CSCs (symmetrical division) and tumor-amplifying daughter cells (asymmetric division). CSCs are thought to reside in niches similar to those of normal stem cells as described for neural, intestinal, and epidermal tissue, are resistant to chemotherapy, and are responsible for tumor recurrence. We recently described the niche-like nature of mouse renal adenocarcinoma (RENCA) cells following encapsulation in agarose macrobeads. In this paper we tested the hypothesis that encapsulated RENCA colonies function as an in vitro model of a CSC niche and that the majority of cells would undergo chemotherapy-induced death, followed by tumor recurrence. After exposure to docetaxel (5 µg/ml), 50% of cells were lost one week post-treatment while only one or two cells remained in each colony by 6 weeks. Surviving cells expressed OCT4 and reformed tumors at 16 weeks post-treatment. Docetaxel-resistant cells also grew as monolayers in cell culture (16–17 weeks post-exposure) or as primary tumors following transplantation to Balb/c mice (6 of 10 mice) or NOD.CB17-Prkdcscid/J mice (9 of 9 mice; 10 weeks post-transplantation or 28 weeks post-exposure). These data support the hypothesis that a rare subpopulation of OCT4+ cells are resistant to docetaxel and these cells are sufficient for tumor recurrence. The reported methodology can be used to obtain purified populations of tumor-initiating cells, to screen for anti-tumor-initiating cell agents, and to investigate the in vitro correlate of a CSC niche, especially as it relates to chemo-resistance and tumor recurrence. PMID:24025409

  6. Durable flame retardant finish for silk fabric using boron hybrid silica sol

    NASA Astrophysics Data System (ADS)

    Zhang, Qiang-hua; Gu, Jiali; Chen, Guo-qiang; Xing, Tie-ling

    2016-11-01

    A hybrid silica sol was prepared via sol gel method using tetraethoxysilane (TEOS) as a precursor and boric acid (H3BO3) as flame retardant additive and then applied to silk fabric. In order to endow silk fabric with durable flame retardancy, 1,2,3,4-butanetetracarboxylic acid (BTCA) was used as cross-linking agent for the sake of strong linkage formation between the hybrid silica sol and silk fabric. The FT-IR and XPS analysis demonstrated the Si-O-B formation in the sol system, as well as the linkage between the sol and silk after the treatment. The limiting oxygen index (LOI) and smoke density test indicated good flame retardancy and smoke suppression of the treated silk fabrics. The micro calorimeter combustion (MCC) test and thermo gravimetric (TG) analysis showed that the treated samples had less weight loss in the high temperature and lower heat release rate when burning. The washing durability evaluation results indicated that there was a distinct improvement for the silk samples treated with BTCA even after 30 times washing. In addition, the influence of the processing order of BTCA and silica sol treatment on the limiting oxygen index (LOI) of the finished silk fabric was also investigated. And the results demonstrated that the sample treated with BTCA first and then with the silica sol exhibited better LOI value (32.3%) than that of the sample by the conversed treatment order. Moreover the tensile property of treated samples was nearly unchanged, but the handle of sol treated samples obviously decreased.

  7. Analysis of FMR-1 locus in a mentally retarded male patient: Mosaicism or duplication?

    SciTech Connect

    Moore, D.K.; Evans, J.P.; Levy-Lahad, E.

    1994-09-01

    Analysis of the CGG repeat region in the FMR-1 allele(s) in a mentally retarded male patient showed two discrete and different sized bands in the premutation range. Southern analysis with EcoRI and EagI revealed bands estimated to represent 54 and 139 repeats of the trinucleotide CGG. Neither band was methylated. No normal sized band was detected. The size of the 54 CGG repeat was confirmed by polyacrylamide gel electrophoresis of the PCR product spanning the CGG repeat region; the 139 repeat was too large for this analysis. Two discrete bands, an unexpected result in a male patient, could represent somatic mosaicism of a single allele. However, in other patients, mosaicism results in a smeared band representing a range of fragment sizes rather than 2 discrete bands. Alternatively, two such bands could indicate that our patient has 2 copies on the FMR-1 allele. A cytogenetic analysis was performed to investigate fragile sites or a duplication. No fragile site was observed in 100 unbanded metaphases examined, ruling out the presence of fragile X in greater than 3% of cells with 0.95 confidence. No evidence of rearrangement of the X chromosome was seen in 50 cells examined, ruling out 6% or greater mosaicism at 0.95 confidence level. A duplication of the FMR-1 allele that is below the resolution of these techniques cannot be ruled out. Physical exam of this patient showed characteristic facies of fragile X syndrome and macroorchidism. The patient had an uncle with mental retardation and similar features and a brother with mental retardation. Clinical symptoms of fragile X are not expected in a patient with an unmethylated FMR-1 allele and an expansion in the premutation range. It is unclear whether the features consistent with fragile X syndrome in this patient are related to the observed molecular occurrences at the FMR-1 allele.

  8. Retardation of Abeta fibril formation by phospholipid vesicles depends on membrane phase behavior.

    PubMed

    Hellstrand, Erik; Sparr, Emma; Linse, Sara

    2010-05-19

    An increasing amount of evidence suggests that in several amyloid diseases, the fibril formation in vivo and the mechanism of toxicity both involve membrane interactions. We have studied Alzheimer's disease related amyloid beta peptide (Abeta). Recombinant Abeta(M1-40) and Abeta(M1-42) produced in Escherichia coli, allows us to carry out large scale kinetics assays with good statistics. The amyloid formation process is followed in means of thioflavin T fluorescence at relatively low (down to 380 nM) peptide concentration approaching the physiological range. The lipid membranes are introduced in the system as large and small unilamellar vesicles. The aggregation lagtime increases in the presence of lipid vesicles for all situations investigated and the phase behavior of the membrane in the vesicles has a large effect on the aggregation kinetics. By comparing vesicles with different membrane phase behavior we see that the solid gel phase dipalmitoylphosphatidylcholine bilayers cause the largest retardation of Abeta fibril formation. The membrane-induced retardation reaches saturation and is present when the vesicles are added during the lag time up to the nucleation point. No significant difference is detected in lag time when increasing amount of negative charge is incorporated into the membrane. PMID:20483329

  9. A tailored three-dimensionally printable agarose-collagen blend allows encapsulation, spreading, and attachment of human umbilical artery smooth muscle cells.

    PubMed

    Köpf, Marius; Campos, Daniela F Duarte; Blaeser, Andreas; Sen, Kshama S; Fischer, Horst

    2016-01-01

    In recent years, novel biofabrication technologies have enabled the rapid manufacture of hydrogel-cell suspensions into tissue-imitating constructs. The development of novel materials for biofabrication still remains a challenge due to a gap between contradicting requirements such as three-dimensional printability and optimal cytocompatibility. We hypothesise that blending of different hydrogels could lead to a novel material with favourable biological and printing properties. In our work, we combined agarose and type I collagen in order to develop a hydrogel blend capable of long-term cell encapsulation of human umbilical artery smooth muscle cells (HUASMCs) and 3D drop-on-demand printing. Different blends were prepared with 0.25%, 0.5%, 0.75%, and 1.5% agarose and 0.2% type I collagen. The cell morphology of HUASMCs and the printing accuracy were assessed for each agarose-collagen combination, keeping the content of collagen constant. The hydrogel blend which displayed sufficient cell spreading and printing accuracy (0.5% agarose, 0.2% type I collagen, AGR0.5COLL0.2) was then characterised based on swelling and degradation over 21 days and mechanical stiffness. The cellular response regarding cell attachment of HUASMCs embedded in the hydrogel blend was further studied using SEM, TEM, and TPLSM. Printing trials were fabricated in a drop-on-demand printing process. The swelling and degradation evaluation showed an average of 20% mass loss and less than 10% swelling. AGR0.5COLL0.2 exhibited significant increase in stiffness compared to pure agarose and type I collagen. In addition, columns of AGR0.5COLL0.2 three centimeters in height were successfully printed submerged in cooled perfluorocarbon, proving the intrinsic printability of the hydrogel blend. Ultimately, a promising novel hydrogel blend showing cell spreading and attachment as well as suitability for bioprinting was identified and could, for example, serve in the manufacture of in vitro 3D models to

  10. The Effects of a Retarded Child's Social Initiations on the Behavior of Severely Retarded School-Aged Peers.

    ERIC Educational Resources Information Center

    Kerr, Mary Margaret; Young, Clifford C.

    1979-01-01

    To increase the social responsiveness of two severely retarded and withdrawn children (six and ten years old), a five-year-old mildly retarded peer was trained to emit social approach behaviors using a procedure in which edible reinforcement was delivered by the trained peer contingent upon positive social response by the target subjects.…

  11. Residential Programming for Mentally Retarded Persons. Volume I, Prevailing Attitudes and Practices in the Field of Mental Retardation.

    ERIC Educational Resources Information Center

    National Association for Retarded Children, Arlington, TX. South Central Regional Office.

    The first of a series of four booklets on residential programing for the mentally retarded reviews for parents the prevailing definitions, attitudes and practices in the field. Mental retardation is defined as subaverage functioning which originates during the developmental period and is associated with impairment in adaptive behavior. The need…

  12. 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.

  13. A novel in situ gel for sustained drug delivery and targeting.

    PubMed

    Ganguly, Sudipta; Dash, Alekha K

    2004-05-19

    The objective of this study was to develop a novel chitosan-glyceryl monooleate (GMO) in situ gel system for sustained drug delivery and targeting. The delivery system consisted of 3% (w/v) chitosan and 3% (w/v) GMO in 0.33M citric acid. In situ gel was formed at a biological pH. In vitro release studies were conducted in Sorensen's phosphate buffer (pH 7.4) and drugs were analyzed either by HPLC or spectrophotometry. Characterization of the gel included the effect of cross-linker, determination of diffusion coefficient and water uptake by thermogravimetric analysis (TGA). Mucoadhesive property of the gel was evaluated in vitro using an EZ-Tester. Incorporation of a cross-linker (glutaraldehyde) retarded the rate and extent of drug release. The in vitro release can further be sustained by replacing the free drug with drug-encapsulated microspheres. Drug release from the gel followed a matrix diffusion controlled mechanism. Inclusion of GMO enhanced the mucoadhesive property of chitosan by three- to sevenfold. This novel in situ gel system can be useful in the sustained delivery of drugs via oral as well as parenteral routes. PMID:15113617

  14. 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

  15. 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

  16. 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.

  17. Flame Retardant Applications in Camping Tents and Potential Exposure.

    PubMed

    Keller, Alexander S; Raju, Nikhilesh P; Webster, Thomas F; Stapleton, Heather M

    2014-02-11

    Concern has mounted over health effects caused by exposure to flame retardant additives used in consumer products. Significant research efforts have focused particularly on exposure to polybrominated diphenyl ethers (PBDEs) used in furniture and electronic applications. However, little attention has focused on applications in textiles, particularly textiles meeting a flammability standard known as CPAI-84. In this study, we investigated flame retardant applications in camping tents that met CPAI-84 standards by analyzing 11 samples of tent fabrics for chemical flame retardant additives. Furthermore, we investigated potential exposure by collecting paired samples of tent wipes and hand wipes from 27 individuals after tent setup. Of the 11 fabric samples analyzed, 10 contained flame retardant additives, which included tris(1,3-dichloroisopropyl) phosphate (TDCPP), decabromodiphenyl ether (BDE-209), triphenyl phosphate, and tetrabromobisphenol-A. Flame retardant concentrations were discovered to be as high as 37.5 mg/g (3.8% by weight) in the tent fabric samples, and TDCPP and BDE-209 were the most frequently detected in these samples. We also observed a significant association between TDCPP levels in tent wipes and those in paired hand wipes, suggesting that human contact with the tent fabric material leads to the transfer of the flame retardant to the skin surface and human exposure. These results suggest that direct contact with flame retardant-treated textiles may be a source of exposure. Future studies will be needed to better characterize exposure, including via inhalation and dermal sorption from air. PMID:24804279

  18. Flame Retardant Applications in Camping Tents and Potential Exposure

    PubMed Central

    2015-01-01

    Concern has mounted over health effects caused by exposure to flame retardant additives used in consumer products. Significant research efforts have focused particularly on exposure to polybrominated diphenyl ethers (PBDEs) used in furniture and electronic applications. However, little attention has focused on applications in textiles, particularly textiles meeting a flammability standard known as CPAI-84. In this study, we investigated flame retardant applications in camping tents that met CPAI-84 standards by analyzing 11 samples of tent fabrics for chemical flame retardant additives. Furthermore, we investigated potential exposure by collecting paired samples of tent wipes and hand wipes from 27 individuals after tent setup. Of the 11 fabric samples analyzed, 10 contained flame retardant additives, which included tris(1,3-dichloroisopropyl) phosphate (TDCPP), decabromodiphenyl ether (BDE-209), triphenyl phosphate, and tetrabromobisphenol-A. Flame retardant concentrations were discovered to be as high as 37.5 mg/g (3.8% by weight) in the tent fabric samples, and TDCPP and BDE-209 were the most frequently detected in these samples. We also observed a significant association between TDCPP levels in tent wipes and those in paired hand wipes, suggesting that human contact with the tent fabric material leads to the transfer of the flame retardant to the skin surface and human exposure. These results suggest that direct contact with flame retardant-treated textiles may be a source of exposure. Future studies will be needed to better characterize exposure, including via inhalation and dermal sorption from air. PMID:24804279

  19. Cellophane film as half wave retarder of wide spectrum

    NASA Astrophysics Data System (ADS)

    Ortiz-Gutiérrez, M.; Olivares-Pérez, A.; Sánchez-Villicaña, V.

    2001-08-01

    In this work, we introduce the use of a cellophane film as a half wave retarder plate of wide spectrum. Using a commercial arc lamp as a light source, we have characterized a cellophane film as half wave plate retarder in the spectral range from λ=400 to 700 nm. In addition, we made similar characterizations for several commercial laser emission lines. Although this film behaves as other commercial half wave plate retarder devices, it has the advantages of a low cost and an easy availability.

  20. Flame retardant cotton fabrics treated with organophosphorus polymer.

    PubMed

    Abou-Okeil, A; El-Sawy, S M; Abdel-Mohdy, F A

    2013-02-15

    Organo-phosphorus compounds was prepared and applied onto cotton fabrics as flame retarding agent. methacryloloxyethylorthophoshor tetraethyl diamidate (MPD) was prepared and its structure was confirmed by IR, NMR and mass spectroscopy. Pyrovatex as commercial flame retardant was used for comparative study. Impregnation method was used as coating for the application of the organophosphorus compounds to cotton fabrics. The major factors affecting the reaction were studied. The results show that the prepared organophosphorus compound can be successfully used as flame retardant for cotton fabrics. PMID:23399290