WorldWideScience

Sample records for gel n-1-carboxy-6-hydroxy benzylidenepropylamine

  1. Thermoresponsive Gels

    OpenAIRE

    Taylor, M. Joan; Tomlins, P.; Sahota, T. S.

    2016-01-01

    An invited review and relates to the responsive gel used in the "artificial pancreas" work og INsmart, DMU. This article is an Open Access journal. Thermoresponsive gelling materials constructed from natural and synthetic polymers can be used to provide triggered action and therefore customised products such as drug delivery and regenerative medicine types as well as for other industries. Some materials give Arrhenius-type viscosity changes based on coil to globule transitions. Others ...

  2. Thermoresponsive Gels

    Directory of Open Access Journals (Sweden)

    M. Joan Taylor

    2017-01-01

    Full Text Available Thermoresponsive gelling materials constructed from natural and synthetic polymers can be used to provide triggered action and therefore customised products such as drug delivery and regenerative medicine types as well as for other industries. Some materials give Arrhenius-type viscosity changes based on coil to globule transitions. Others produce more counterintuitive responses to temperature change because of agglomeration induced by enthalpic or entropic drivers. Extensive covalent crosslinking superimposes complexity of response and the upper and lower critical solution temperatures can translate to critical volume temperatures for these swellable but insoluble gels. Their structure and volume response confer advantages for actuation though they lack robustness. Dynamic covalent bonding has created an intermediate category where shape moulding and self-healing variants are useful for several platforms. Developing synthesis methodology—for example, Reversible Addition Fragmentation chain Transfer (RAFT and Atomic Transfer Radical Polymerisation (ATRP—provides an almost infinite range of materials that can be used for many of these gelling systems. For those that self-assemble into micelle systems that can gel, the upper and lower critical solution temperatures (UCST and LCST are analogous to those for simpler dispersible polymers. However, the tuned hydrophobic-hydrophilic balance plus the introduction of additional pH-sensitivity and, for instance, thermochromic response, open the potential for coupled mechanisms to create complex drug targeting effects at the cellular level.

  3. Removing water from gels

    International Nuclear Information System (INIS)

    Lane, E.S.; Winter, J.A.

    1982-01-01

    Water is removed from a gel material by contacting the gel material with an organic liquid and contacting the organic liquid with a gas such that water is taken up by the gas. The invention, in one embodiment, may be used to dry gel materials whilst maintaining an open porous network therein. In one example, the invention is applied to gel precipitated spheres containing uranium and plutonium. (author)

  4. Polymer gels and networks

    National Research Council Canada - National Science Library

    Osada, Yoshihito; Khokhlov, A. R

    2002-01-01

    ... or magnetic field, etc.). It was realized that not only can polymer gels absorb and hold a considerable volume of liquids, but they can also be forced to expel the absorbed liquid in a controlled manner. Of particular interest are hydrogels, i.e., polymer gels, which swell extensively in water. The most common hydrogels are polyelectrolyte gels: ...

  5. Transport Phenomena in Gel

    Directory of Open Access Journals (Sweden)

    Masayuki Tokita

    2016-05-01

    Full Text Available Gel becomes an important class of soft materials since it can be seen in a wide variety of the chemical and the biological systems. The unique properties of gel arise from the structure, namely, the three-dimensional polymer network that is swollen by a huge amount of solvent. Despite the small volume fraction of the polymer network, which is usually only a few percent or less, gel shows the typical properties that belong to solids such as the elasticity. Gel is, therefore, regarded as a dilute solid because its elasticity is much smaller than that of typical solids. Because of the diluted structure, small molecules can pass along the open space of the polymer network. In addition to the viscous resistance of gel fluid, however, the substance experiences resistance due to the polymer network of gel during the transport process. It is, therefore, of importance to study the diffusion of the small molecules in gel as well as the flow of gel fluid itself through the polymer network of gel. It may be natural to assume that the effects of the resistance due to the polymer network of gel depends strongly on the network structure. Therefore, detailed study on the transport processes in and through gel may open a new insight into the relationship between the structure and the transport properties of gel. The two typical transport processes in and through gel, that is, the diffusion of small molecules due to the thermal fluctuations and the flow of gel fluid that is caused by the mechanical pressure gradient will be reviewed.

  6. Sol-Gel Glasses

    Science.gov (United States)

    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.

  7. GelTouch

    DEFF Research Database (Denmark)

    Miruchna, Viktor; Walter, Robert; Lindlbauer, David

    2015-01-01

    We present GelTouch, a gel-based layer that can selectively transition between soft and stiff to provide tactile multi-touch feedback. It is flexible, transparent when not activated, and contains no mechanical, electromagnetic, or hydraulic components, resulting in a compact form factor (a 2mm thin...... touchscreen layer for our prototype). The activated areas can be morphed freely and continuously, without being limited to fixed, predefined shapes. GelTouch consists of a poly(N-isopropylacrylamide) gel layer which alters its viscoelasticity when activated by applying heat (>32 C). We present three different...

  8. Transport Phenomena in Gel

    OpenAIRE

    Masayuki Tokita

    2016-01-01

    Gel becomes an important class of soft materials since it can be seen in a wide variety of the chemical and the biological systems. The unique properties of gel arise from the structure, namely, the three-dimensional polymer network that is swollen by a huge amount of solvent. Despite the small volume fraction of the polymer network, which is usually only a few percent or less, gel shows the typical properties that belong to solids such as the elasticity. Gel is, therefore, regarded as a dilu...

  9. Cyanocobalamin Nasal Gel

    Science.gov (United States)

    ... to supply extra vitamin B12 to people who need unusually large amounts of this vitamin because they are pregnant or have certain diseases. ... Cyanocobalamin nasal gel will supply you with enough vitamin B12 only as ... it regularly. You may need to use cyanocobalamin nasal gel every week for ...

  10. Modeling chemoresponsive polymer gels.

    Science.gov (United States)

    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.

  11. Periodic mesoporous silica gels

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, M.T.; Martin, J.E.; Odinek, J.G. [and others

    1996-06-01

    We have synthesized monolithic particulate gels of periodic mesoporous silica by adding tetramethoxysilane to a homogeneous alkaline micellar precursor solution. The gels exhibit 5 characteristic length scales over 4 orders of magnitude: fractal domains larger than the particle size (>500 nm), particles that are {approximately}150 to 500 nm in diameter, interparticle pores that are on the order of the particle size, a feature in the gas adsorption measurements that indicates pores {approximately}10-50 nm, and periodic hexagonal arrays of {approximately}3 nm channels within each particle. The wet gel monoliths exhibit calculated densities as low as {approximately}0.02 g/cc; the dried and calcined gels have bulk densities that range from {approximately}0.3-0.5 g/cc. The materials possess large interparticle ({approximately}1.0-2.3 cc/g) and intraparticle ({approximately}0.6 cc/g) porosities.

  12. Gel purification of RNA.

    Science.gov (United States)

    Nilsen, Timothy W

    2013-02-01

    For many applications, including size selection of RNAs and purification of in vitro transcription products, it is necessary to purify RNAs on a denaturing gel. This procedure describes how to purify transcripts that have been synthesized in vitro. It is useful for labeled or unlabeled RNAs when sufficient mass is present. It can also be used to isolate small RNAs. In general, RNA purification by denaturing gel electrophoresis is practical only when the size of the desired RNA is 600 nucleotides or less.

  13. Conformance Improvement Using Gels

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. Active Polymer Gel Actuators

    Directory of Open Access Journals (Sweden)

    Shuji Hashimoto

    2010-01-01

    Full Text Available Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of heart muscles. Here we show a novel biomimetic gel actuator that can walk spontaneously with a wormlike motion without switching of external stimuli. The self-oscillating motion is produced by dissipating chemical energy of oscillating reaction. Although the gel is completely composed of synthetic polymer, it shows autonomous motion as if it were alive.

  15. 3D MR gel dosimetry with lung equivalent gel; 3D MR-Gel-Dosimetrie mit lungenaequivalentem Gel

    Energy Technology Data Exchange (ETDEWEB)

    Scherer, J.; Solleder, M.; Schiessl, I.; Bogner, L.; Herbst, M. [Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie, Regensburg Univ. (Germany)

    1998-12-31

    The MR gel dosimetry is used to verify complex 3D treatment plans. Till now this method served only for dose evaluation in homogeneous phantoms. On the way to build a heterogeneous anthropomorphic gel phantom, a lung equivalent gel with the density 0.4 g/cm{sup 3} was developed. First experiments show a 1.55 times higher dose reponse in the low density gel (LD gel). The comparison of a dose distribution in a gel/LD gel/gel slab phantom with Monte Carlo calculations shows good agreement within 5%. More over the accuray of the measuring device magnetic resonance imager was studied in respect to the now exclusive digital image processing with the software MRD (MR dosimetry). Because of the dimensions of the Fricke gel phantom an artefact correction, based on the data from the unirradiated phantom proved to be essential. (orig.) [Deutsch] Die MR-Gel-Dosimetrie zur Verifikation komplexer 3D-Bestrahlungsplaene wurde bislang ausschliesslich in homogenen Phantomen durchgefuehrt. Auf dem Wege zum Bau eines inhomogenen Humanoid-Gel-Phantoms wurde ein lungenaequivalentes Gel mit der Dichte 0,4 g/cm{sup 3} entwickelt. Erste Messungen zeigen ein um den Faktor 1,55 hoeheres Ansprechvermoegen in dem low-density-Gel (LD-Gel). Der Vergleich einer gemessen Dosisverteilung in einem Gel/LD-Gel/Gel Schichtphantom als einfaches Thoraxmodell mit Monte-Carlo-Rechnungen zeigt eine gute Uebereinstimmung innerhalb 5%. Ausserdem wurden Untersuchungen zur Messgenauigkeit des Kernspintomographen im Rahmen der nun ausschliesslich digitalen Auswertung mit Hilfe des Programms MRD (MR-Dosimetrie) durchgefuehrt. Es zeigt sich, dass eine Artefaktkorrektur auf der Basis einer Messung des unbestrahlten Phantoms bei grossen Fricke-Gel-Phantomen notwendig ist. (orig.)

  16. based gel polymer electrolytes

    Indian Academy of Sciences (India)

    Bull. Mater. Sci., Vol. 29, No. 7, December 2006, pp. 673–678. © Indian Academy of Sciences. 673. Investigation on poly (vinylidene fluoride) based gel polymer electrolytes ... (Alamgir and Abraham 1993; Sukeshini et al 1996; Ra- jendran and Uma ... Yang et al 1996; Ramesh and Arof 2001) and such elec- trolytes exhibit ...

  17. gel template method

    Indian Academy of Sciences (India)

    TiO2 nanotubes have been synthesized by sol–gel template method using alumina membrane. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, UV absorption spectrum and X-ray diffraction techniques have been used to investigate the structure, morphology and optical ...

  18. Biopolymer gels containing fructooligosaccharides.

    Science.gov (United States)

    Silva, Karen Cristina Guedes; Sato, Ana Carla Kawazoe

    2017-11-01

    The influence of the addition of fructooligosaccharide (FOS) in an external gelated alginate/gelatin biopolymer matrix, was evaluated in order to produce biopolymeric structures with functional effects. Solutions were characterized regarding their rheological properties, macrogels regarding their microstructure and mechanical properties and microgels were characterized in relation to their particle size distribution and morphology. Close relationship was found between the microstructure, rheological and mechanical properties of the biopolymeric systems. An increased viscosity and accentuated elastic and pseudoplastic behavior were associated to denser microstructures. The FOS addition caused changes in the evaluated properties, resulting in more cohesive structures, with smaller pores and higher viscosity, compared to alginate-gelatin gels. The addition of 3% FOS to biopolymeric system provided an optimal condition, allowing the formation of stronger gels, with smaller pores and beads with smaller sizes, indicating the potential use of these functional systems as texture modifiers or encapsulation systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Chiromagnetic nanoparticles and gels

    Science.gov (United States)

    Yeom, Jihyeon; Santos, Uallisson S.; Chekini, Mahshid; Cha, Minjeong; de Moura, André F.; Kotov, Nicholas A.

    2018-01-01

    Chiral inorganic nanostructures have high circular dichroism, but real-time control of their optical activity has so far been achieved only by irreversible chemical changes. Field modulation is a far more desirable path to chiroptical devices. We hypothesized that magnetic field modulation can be attained for chiral nanostructures with large contributions of the magnetic transition dipole moments to polarization rotation. We found that dispersions and gels of paramagnetic Co3O4 nanoparticles with chiral distortions of the crystal lattices exhibited chiroptical activity in the visible range that was 10 times as strong as that of nonparamagnetic nanoparticles of comparable size. Transparency of the nanoparticle gels to circularly polarized light beams in the ultraviolet range was reversibly modulated by magnetic fields. These phenomena were also observed for other nanoscale metal oxides with lattice distortions from imprinted amino acids and other chiral ligands. The large family of chiral ceramic nanostructures and gels can be pivotal for new technologies and knowledge at the nexus of chirality and magnetism.

  20. Polyacrylamide gel electrophoresis of RNA.

    Science.gov (United States)

    Rio, Donald C; Ares, Manuel; Hannon, Gregory J; Nilsen, Timothy W

    2010-06-01

    Perhaps the most important and certainly the most often used technique in RNA analysis is gel electrophoresis. This technique is generally applicable for RNA detection, quantification, purification by size, and quality assessment. Because RNAs are negatively charged, they migrate toward the anode in the presence of electric current. The gel acts as a sieve to selectively impede the migration of the RNA in proportion to its mass, given that its mass is generally proportional to its charge. Because mass is approximately related to chain length, the length of an RNA is more generally determined by its migration. In addition, topology (i.e., circularity) can affect migration, making RNAs appear longer on the gel than they actually are. Gels are used in a wide variety of techniques, including Northern blotting, primer extension, footprinting, and analyzing processing reactions. They are invaluable as preparative and fractionating tools. There are two common types of gel: polyacrylamide and agarose. For most applications, denaturing acrylamide gels are most appropriate. These gels are extremely versatile and can resolve RNAs from ~600 to RNA-protein complexes, native gels are appropriate. The only disadvantage to acrylamide gels is that they are not suitable for analyzing large RNAs (> or =600 nt); for such applications, agarose gels are preferred. This protocol describes how to prepare, load, and run polyacrylamide gels for RNA analysis.

  1. Radiotherapy gel dosimetry

    International Nuclear Information System (INIS)

    Baldock, C.

    2002-01-01

    shapes and sizes while sparing normal tissue. The situation is further complicated if the normal tissues are critical organs or are particularly sensitive to radiation. Radiotherapy techniques employed to obtain a closer conformation of the dose distribution to the tumour volume are referred to as conformal radiotherapy techniques. The clinical implementation of conformal therapy has been delayed by limitations in the verification of conformal dose distributions calculated by treatment planning systems prior to the irradiation of the patient and the verification of complex treatments during its delivery to the patient. There are several aspects of conformal therapy that complicate dose verification. To achieve the dose distributions conforming to complex 3D volumes, high dose gradients arise in the treatment volume. Further, overdose or underdose regions can exist when separate radiation fields are used to deliver additional radiation. These aspects require that practical dose measurement (dosimetry) techniques be able to integrate dose over time and easily measure dose distributions in 3D with high spatial resolution. Traditional dosimeters, such as ion chambers, thermoluminescent dosimeters and radiographic film do not fulfil these requirements. Novel gel dosimetry techniques are being developed in which dose distributions can potentially be determined in vitro in 3D using anthropomorphic phantoms to simulate a clinically irradiated situation. As long ago as the 1950's, radiation-induced colour change in dyes was used to investigate radiation doses in gels. It was subsequently shown that radiation induced changes in nuclear magnetic resonance (NMR) relaxation properties of gels infused with conventional Fricke dosimetry solutions could be measured using magnetic resonance imaging (MRI). In Fricke gels, Fe 2+ ions in ferrous sulphate solutions are usually dispersed throughout a gelatin, agarose or PVA matrix. Radiation-induced changes in the dosimeters are considered to

  2. Gel polymer electrolytes for batteries

    Science.gov (United States)

    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.

  3. Thoria sol-gel processes

    International Nuclear Information System (INIS)

    Matthews, R.B.

    1978-10-01

    Alternate fuel fabrication techniques are being developed at WNRE as part of the thorium fuel cycle program. The sol-gel techniques are attractive and this report assembles and summarizes information relating to thoria sol-gel fuels. Some background information on the behaviour and advantages of sol-gel fuel forms is presented, followed by a review of relevant colloid chemistry and an explanation of the fundamental steps of sol-gel processes. Finally, several variants to the basic process are reviewed and evaluated. (author)

  4. Radiotherapy gel dosimetry: a review

    International Nuclear Information System (INIS)

    Baldock, C.

    2003-01-01

    Radiation therapy or radiotherapy is a common form of cancer treatment. Recent advances in radiotherapy such as intensity modulated radiation therapy indicate that treatment outcomes may be improved. The principle limitation of these more advanced techniques of radiation therapy is the ability to quantify the absorbed radiation dose to the tumour which is related to the 3- dimensional geometry of the tumour. The main advances in 3-dimensional radiation dosimetry are the development of radiation sensitive polymer gel dosimeters. The use of radiation sensitive gels for radiation dosimetry in cancer therapy was first suggested in the 1950s. It was subsequently shown in 1984 that radiation induced changes in nuclear magnetic resonance relaxation properties of gels infused with conventional Fricke dosimetry solutions could be measured. Due to diffusion-related limitations in the use of Fricke gels, alternative polymer gel dosimeters were subsequently suggested in 1992. Since then, both magnetic resonance and optical imaging techniques have been used to evaluate polymer gel dosimeters to produce three-dimensional radiation dose distributions. More recently the uses of x-ray computer tomography and vibrational spectroscopy have also been demonstrated as valuable techniques in the evaluation of these dosimetry gels. Although not yet used routinely clinically, applications of these radiologically soft-tissue equivalent gel dosimeters have been shown to have great potential in the evaluation of complex radiation dose distributions. A review of 3-dimensional radiotherapy gel dosimetry is presented

  5. Rheology and structure of milk protein gels

    NARCIS (Netherlands)

    Vliet, van T.; Lakemond, C.M.M.; Visschers, R.W.

    2004-01-01

    Recent studies on gel formation and rheology of milk gels are reviewed. A distinction is made between gels formed by aggregated casein, gels of `pure` whey proteins and gels in which both casein and whey proteins contribute to their properties. For casein' whey protein mixtures, it has been shown

  6. Gel placement in porous media

    NARCIS (Netherlands)

    F.J. Vermolen; J. Bruining; C.J. van Duijn (Hans)

    1999-01-01

    textabstractIn this paper we analyse advective transport of polymers, crosslinkers and gel, taking into account non-equilibrium gelation, gel adsorption and crosslinker precipitation. In absence of diffusion/dispersion the resulting model consists of hyperbolic transport-reaction equations. These

  7. Chemical Gel for Surface Decontamination

    International Nuclear Information System (INIS)

    Jung, Chong Hun; Moon, J. K.; Won, H. J.; Lee, K. W.; Kim, C. K.

    2010-01-01

    Many chemical decontamination processes operate by immersing components in aggressive chemical solutions. In these applications chemical decontamination technique produce large amounts of radioactive liquid waste. Therefore it is necessary to develop processes using chemical gels instead of chemical solutions, to avoid the well-known disadvantages of chemical decontamination techniques while retaining their high efficiency. Chemical gels decontamination process consists of applying the gel by spraying it onto the surface of large area components (floors, walls, etc) to be decontaminated. The gel adheres to any vertical or complex surface due to their thixotropic properties and operates by dissolving the radioactive deposit, along with a thin layer of the gel support, so that the radioactivity trapped at the surface can be removed. Important aspects of the gels are that small quantities can be used and they show thixitropic properties : liquid during spraying, and solid when stationary, allowing for strong adherence to surfaces. This work investigates the decontamination behaviors of organic-based chemical gel for SS 304 metallic surfaces contaminated with radioactive materials

  8. Denaturing gradient gel electrophoresis

    International Nuclear Information System (INIS)

    Kocherginskaya, S.A.; Cann, I.K.O.; Mackie, R.I.

    2005-01-01

    It is worthwhile considering that only some 30 species make up the bulk of the bacterial population in human faeces at any one time based on the classical cultivation-based approach. The situation in the rumen is similar. Thus, it is practical to focus on specific groups of interest within the complex community. These may be the predominant or the most active species, specific physiological groups or readily identifiable (genetic) clusters of phylogenetically related organisms. Several 16S rDNA fingerprinting techniques can be invaluable for selecting and monitoring sequences or phylogenetic groups of interest and are described below. Over the past few decades, considerable attention was focussed on the identification of pure cultures of microbes on the basis of genetic polymorphisms of DNA encoding rRNA such as ribotyping, amplified fragment length polymorphism and randomly amplified polymorphic DNA. However, many of these methods require prior cultivation and are less suitable for use in analysis of complex mixed populations although important in describing cultivated microbial diversity in molecular terms. Much less attention was given to molecular characterization of complex communities. In particular, research into diversity and community structure over time has been revolutionized by the advent of molecular fingerprinting techniques for complex communities. Denaturing or temperature gradient gel electrophoresis (DGGE/TGGE) methods have been successfully applied to the analysis of human, pig, cattle, dog and rodent intestinal populations

  9. Fluoride Rinses, Gels and Foams

    DEFF Research Database (Denmark)

    Twetman, Svante; Keller, Mette K

    2016-01-01

    AIM: The aim of this conference paper was to systematically review the quality of evidence and summarize the findings of clinical trials published after 2002 using fluoride mouth rinses, fluoride gels or foams for the prevention of dental caries. METHODS: Relevant papers were selected after...... (6 on fluoride mouth rinse, 10 on fluoride gel and 3 on fluoride foam); 6 had a low risk of bias while 2 had a moderate risk. All fluoride measures appeared to be beneficial in preventing crown caries and reversing root caries, but the quality of evidence was graded as low for fluoride mouth rinse......, moderate for fluoride gel and very low for acidulated fluoride foam. No conclusions could be drawn on the cost-effectiveness. CONCLUSIONS: This review, covering the recent decade, has further substantiated the evidence for a caries-preventive effect of fluoride mouth rinse, fluoride gel and foam...

  10. Injectable gels for tissue engineering.

    Science.gov (United States)

    Gutowska, A; Jeong, B; Jasionowski, M

    2001-08-01

    Recently, tissue engineering approaches using injectable, in situ gel forming systems have been reported. In this review, the gelation processes and several injectable systems that exhibit in situ gel formation at physiological conditions are discussed. Applications of selected injectable systems (alginate, chitosan, hyaluronan, polyethylene oxide/polypropylene oxide) in tissue engineering are also described. Injectable polymer formulation can gel in vivo in response to temperature change (thermal gelation), pH change, ionic cross-linking, or solvent exchange. Kinetics of gelation is directly affected by its mechanism. Injectable formulations offer specific advantages over preformed scaffolds such as: possibility of a minimally invasive implantation, an ability to fill a desired shape, and easy incorporation of various therapeutic agents. Several factors need to be considered before an injectable gel can be selected as a candidate for tissue engineering applications. Apart from tissue-specific cell-matrix interactions, the following gel properties need to be considered: gelation kinetics, matrix resorption rate, possible toxicity of degradation products and their elimination routes, and finally possible interference of the gel matrix with histogenesis. Copyright 2001 Wiley-Liss, Inc.

  11. Bleach gel: a simple agarose gel for analyzing RNA quality.

    Science.gov (United States)

    Aranda, Patrick S; LaJoie, Dollie M; Jorcyk, Cheryl L

    2012-01-01

    RNA-based applications requiring high-quality, non-degraded RNA are a foundational element of many research studies. As such, it is paramount that the integrity of experimental RNA is validated prior to cDNA synthesis or other downstream applications. In the absence of expensive equipment such as microfluidic electrophoretic devices, and as an alternative to the costly and time-consuming standard formaldehyde gel, RNA quality can be quickly analyzed by adding small amounts of commercial bleach to TAE buffer-based agarose gels prior to electrophoresis. In the presence of low concentrations of bleach, the secondary structure of RNA is denatured and potential contaminating RNases are destroyed. Because of this, the 'bleach gel' is a functional approach that addresses the need for an inexpensive and safe way to evaluate RNA integrity and will improve the ability of researchers to rapidly analyze RNA quality. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Polyacrylamide temperature gradient gel electrophoresis.

    Science.gov (United States)

    Viglasky, Viktor

    2013-01-01

    Temperature Gradient Gel Electrophoresis (TGGE) is a form of electrophoresis in which temperature gradient is used to denature molecules as they move through either acrylamide or agarose gel. TGGE can be applied to analyze DNA, RNA, protein-DNA complexes, and, less commonly, proteins. Separation of double-stranded DNA molecules during TGGE relies on temperature-dependent melting of the DNA duplex into two single-stranded DNA molecules. Therefore, the mobility of DNA reflects not only the size of the molecule but also its nucleotide composition, thereby allowing separation of DNA molecules of similar size with different sequences. Depending on the relative orientation of electric field and temperature gradient, TGGE can be performed in either a parallel or a perpendicular mode. The former is used to analyze multiple samples in the same gel, whereas the later allows detailed analysis of a single sample. This chapter is focused on analysis of DNA by polyacrylamide TGGE using the perpendicular mode.

  13. Sol-gel derived sorbents

    Science.gov (United States)

    Sigman, Michael E.; Dindal, Amy B.

    2003-11-11

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

  14. Screening effect on nanostructure of charged gel

    DEFF Research Database (Denmark)

    Sugiyama, M; Annaka, M; Hino, M

    2004-01-01

    Charge screening effects on nanostructures of N-isopropylacrylamide-sodium acrylate (NIPA-SA) and -acrylic acid (NIPA-AAc) gels are investigated with small-angle neutron scattering. The NIPA-SA and NIPA-AAc gels with low water content exhibit microphase separations with different dimensions....... The dehydrated NIPA-SA gel also makes the microphase separation but the dehydrated NIPA-AAc gel does not. These results indicate that ionic circumstance around charged bases strongly affects the nanostructures both of the dehydrated gel and the gel with low water content. (C) 2004 Elsevier B. V. All rights...

  15. Screening effect on nanostructure of charged gel

    International Nuclear Information System (INIS)

    Sugiyama, Masaaki; Annaka, Masahiko; Hino, Masahiro; Fukunaga, Toshiharu; Vigild, Martin E.; Hara, Kazuhiro

    2004-01-01

    Charge screening effects on nanostructures of N-isopropylacrylamide-sodium acrylate (NIPA-SA) and -acrylic acid (NIPA-AAc) gels are investigated with small-angle neutron scattering. The NIPA-SA and NIPA-AAc gels with low water content exhibit microphase separations with different dimensions. The dehydrated NIPA-SA gel also makes the microphase separation but the dehydrated NIPA-AAc gel does not. These results indicate that ionic circumstance around charged bases strongly affects the nanostructures both of the dehydrated gel and the gel with low water content

  16. Screening effect on nanostructure of charged gel

    Science.gov (United States)

    Sugiyama, Masaaki; Annaka, Masahiko; Hino, Masahiro; Fukunaga, Toshiharu; E. Vigild, Martin; Hara, Kazuhiro

    2004-07-01

    Charge screening effects on nanostructures of N-isopropylacrylamide-sodium acrylate (NIPA-SA) and -acrylic acid (NIPA-AAc) gels are investigated with small-angle neutron scattering. The NIPA-SA and NIPA-AAc gels with low water content exhibit microphase separations with different dimensions. The dehydrated NIPA-SA gel also makes the microphase separation but the dehydrated NIPA-AAc gel does not. These results indicate that ionic circumstance around charged bases strongly affects the nanostructures both of the dehydrated gel and the gel with low water content.

  17. Nonlinear elasticity of alginate gels

    Science.gov (United States)

    Hashemnejad, Seyed Meysam; Kundu, Santanu

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

  18. Silica reinforced triblock copolymer gels

    DEFF Research Database (Denmark)

    Theunissen, E.; Overbergh, N.; Reynaers, H.

    2004-01-01

    The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order...

  19. Silicone Gel-Filled Breast Implants

    Science.gov (United States)

    ... and Prosthetics Breast Implants Silicone Gel-Filled Breast Implants Share Tweet Linkedin Pin it More sharing options ... it Email Print Description: Silicone gel-filled breast implants have a silicone outer shell that is filled ...

  20. Surface grafted chitosan gels. Part II. Gel formation and characterization

    DEFF Research Database (Denmark)

    Liu, Chao; Thormann, Esben; Claesson, Per M.

    2014-01-01

    Responsive biomaterial hydrogels attract significant attention due to their biocompatibility and degradability. In order to make chitosan based gels, we first graft one layer of chitosan to silica, and then build a chitosan/poly(acrylic acid) multilayer using the layer-by-layer approach. After...... detachment and decomposition. The chemical reaction between gluteraldehyde, the cross-linking agent, and chitosan was followed in situ using total internal reflection Raman (TIRR) spectroscopy, which provided a molecular insight into the complex reaction mechanism, as well as the means to quantify the cross......-linking density. The amount of poly(acrylic acid) trapped inside the surface grafted films was found to decrease with decreasing cross-linking density, as confirmed in situ using TIRR, and ex situ by Fourier transform infrared (FTIR) measurements on dried films. The responsiveness of the chitosan-based gels...

  1. Yield stress determination of a physical gel

    DEFF Research Database (Denmark)

    Hvidt, Søren

    2013-01-01

    Pluronic F127 solutions form gels in water with high elastic moduli. Pluronic gels can, however, only withstand small deformations and stresses. Different steady shear and oscillatory methods traditionally used to determine yield stress values are compared. The results show that the yield stresse...... values of these gels depend on test type and measurement time, and no absolute yield stress value can be determined for these physical gels....

  2. Physical Properties of Silicone Gel Breast Implants.

    Science.gov (United States)

    Jewell, Mark L; Bengtson, Bradley P; Smither, Kate; Nuti, Gina; Perry, TracyAnn

    2018-04-28

    Surgical applications using breast implants are individualized operations to fill and shape the breast. Physical properties beyond shape, size, and surface texture are important considerations during implant selection. Compare form stability, gel material properties, and shell thickness of textured shaped, textured round, and smooth round breast implants from 4 manufacturers: Allergan, Mentor, Sientra, and Establishment Labs through bench testing. Using a mandrel height gauge, form stability was measured by retention of dimensions on device movement from a horizontal to vertical supported orientation. Dynamic response of gel material (gel cohesivity, resistance to gel deformation, energy absorption) was measured using a synchronized target laser following application of graded negative pressure. Shell thickness was measured using digital thickness gauge calipers. Form stability, gel material properties, and shell thickness differed across breast implants. Of textured shaped devices, Allergan Natrelle 410 exhibited greater form stability than Mentor MemoryShape and Sientra Shaped implants. Allergan Inspira round implants containing TruForm 3 gel had greater form stability, higher gel cohesivity, greater resistance to gel deformation, and lower energy absorption than those containing TruForm 2 gel and in turn, implants containing TruForm 1 gel. Shell thickness was greater for textured versus smooth devices, and differed across styles. Gel cohesivity, resistance to gel deformation, and energy absorption are directly related to form stability, which in turn determines shape retention. These characteristics provide information to aid surgeons choosing an implant based on surgical application, patient tissue characteristics, and desired outcome.

  3. Cumulative irritation potential among metronidazole gel 1%, metronidazole gel 0.75%, and azelaic acid gel 15%.

    Science.gov (United States)

    Colón, Luz E; Johnson, Lori A; Gottschalk, Ronald W

    2007-04-01

    Topical therapy for rosacea aims to reduce inflammatory lesions and decrease erythema but can carry side effects such as stinging, pruritus, and burning. Metronidazole and azelaic acid gel 15% are U.S. Food and Drug Administration-approved for the treatment of rosacea. The current study was conducted to assess the cumulative irritation potential of 2 formulations of metronidazole 0.75% gel and 1% gel--and azelaic acid gel 15% over 21 days (N=36). Results of this study demonstrated a significantly greater poten tial for irritation from azelaic acid compared with metronidazole gel 0.75% (P < .0001), which had significantly greater potential for irritation compared with metronidazole gel 1% (P = .0054). Metronidazole gel 1% had a similar profile to white petrolatum.

  4. Nanocrystal/sol-gel nanocomposites

    Science.gov (United States)

    Klimov, Victor L.; Petruska, Melissa A.

    2010-05-25

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

  5. Microphase separation in nanocomposite gels

    Science.gov (United States)

    Osaka, Noboru; Endo, Hitoshi; Nishida, Toshihiko; Suzuki, Takuya; Li, Huan-Jun; Haraguchi, Kazutoshi; Shibayama, Mitsuhiro

    2009-06-01

    Microphase separation in poly( N -isopropylacrylamide)(PNIPA)-clay nanocomposite hydrogels (NC gels) is investigated by means of contrast-variation small-angle neutron scattering (CV-SANS) and dynamic light scattering (DLS). By using CV-SANS, it is revealed that microphase separation occurs in NC gels above the lower-critical solution temperature (LCST) of PNIPA aqueous solutions. The observed partial scattering functions show that only the spatial distribution of PNIPA chains is highly distorted by microphase separation and PNIPA chains are preferentially adsorbed on the clay surfaces, where the PNIPA-rich phase forms nanoscaled bicontinuous structure mediated by the clay particles. Additional DLS measurements for dilute solutions with PNIPA and/or the clay nanoparticles confirm that aggregation of PNIPA above the LCST is dramatically suppressed by addition of clay particles. Based on these observations, we conclude that strong affinity between the polymer and clay has a significant effect on the phase separation in NC gels and allows one to tune the length scale of the phase separation phenomenon by clay concentration.

  6. Water equivalence of polymer gel dosimeters

    International Nuclear Information System (INIS)

    Sellakumar, P.; James Jebaseelan Samuel, E.; Supe, Sanjay S.

    2007-01-01

    To evaluate the water equivalence and radiation transport properties of polymer gel dosimeters over the wide range of photon and electron energies 14 different types of polymer gels were considered. Their water equivalence was evaluated in terms of effective atomic number (Z eff ), electron density (ρ e ), photon mass attenuation coefficient (μ/ρ), photon mass energy absorption coefficient (μ en /ρ) and total stopping power (S/ρ) tot of electrons using the XCOM and the ESTAR database. The study showed that the effective atomic number of polymer gels were very close ( en /ρ for all polymer gels were in close agreement ( tot of electrons in polymer gel dosimeters were within 1% agreement with that of water. From the study we conclude that at lower energy (<80keV) the polymer gel dosimeters cannot be considered water equivalent and study has to be carried out before using the polymer gel for clinical application

  7. Aspects of dosimetry using radiation sensitive gels

    International Nuclear Information System (INIS)

    Baldock, Clive

    2001-01-01

    The use of radiation sensitive gels for dosimetry measurements was first suggested in the 1950s. It was subsequently shown that radiation induced changes in nuclear magnetic resonance (NMR) relaxation properties of gels infused with conventional Fricke dosimetry solutions could be measured. However, due to predominantly diffusion-related limitations, alternative polymer gel dosimeters were suggested. Clinical applications of these radiologically tissue equivalent gel dosimeters using magnetic resonance imaging (MRI) have subsequently been reported in the literature. In Fricke gels, Fe 2+ ions in ferrous sulphate solutions are usually dispersed throughout a gelatin or agarose hydrogel matrix. Radiation-induced changes in the dosimeters are considered to be either through direct absorption of ionising radiation or via intermediate water free radicals. Fe 2+ ions are converted to Fe 3+ ions with a corresponding change in paramagnetic properties that may be quantified using NMR relaxation measurements. In polymer gels, monomers are also dispersed in a gelatin or agarose hydrogel matrix. Monomers undergo a polymerisation reaction as a function of absorbed dose resulting in a three-dimensional polymer gel matrix. The radiation-induced formation of polymer influences NMR relaxation properties. The growth in polymer also results in other physical changes that may be used to quantify absorbed radiation dose. This thesis investigates various aspects of radiation dosimetry using radiation sensitive gels. Image processing software was developed to calculate NMR relaxation images of dosimetry gels. Measurements were undertaken to investigate the diffusion problem in Fricke gels. Radiological properties were theoretically modelled for both Fricke and polymer gels. A methodology was developed for the preparation of polymer gels. Vibrational spectroscopic studies were undertaken to investigate the underlying mechanism involved in the radiation-induced formation of polymer. MRI

  8. Rheological characterization of Poloxamer 407 nimesulide gels

    Directory of Open Access Journals (Sweden)

    M. N. Freitas

    2009-01-01

    Full Text Available The thermal gelling property of Poloxamer 407- nimesulide gels was characterized by rheological studies. Nimesulide, a local anti-inflammatory and anesthetic drug used for the treatment of acute and chronic pain, has a short duration of action and a long-acting single-dose injection would be of clinical importance. Thus a poloxamer 407 gel applied intramuscularly could prolong the release and action of nimesulide. In this study, aqueous gels with nimesulide, containing three different concentrations of Poloxamer 407, were prepared. Viscosity measurements were performed by rheologial studies to obtain the optimal sol-gel transition temperature . Poloxamer 407 gels are pseudoplastic and viscoelastic materials, which have an elastic modulus (G', characteristic of the solid, and a viscous modulus (G'', characteristic of the liquid material. Moreover, being pseudoplastic gels, when they are deformed by shearing, their viscosity decreases. Increase of the polymer concentration increased the viscosity of the gels, which could affect the releasing process of nimesulide. Furthermore, the presence of nimesulide led to a lowering of the sol-gel transition temperature. Keywords: Poloxamer 407 gels; nimesulide; rheological characterization; viscosity; sol-gel transition temperature.

  9. Calcium Impact on Milk Gels Formation

    DEFF Research Database (Denmark)

    Koutina, Glykeria

    salts. The perturbation of calcium equilibria by these factors will affect the final properties of acid, calcium and rennet milk gels. By decreasing the pH from 6.0 to 5.2 (acid gels), the calcium equilibrium was significantly affected by temperature (4, 20, 30, 40 oC), and different combinations...... enriched dairy products. Calcium gels can be produced by addition of a calcium salt and heat treatment at temperatures higher than 70 oC for several minutes. The combination of heat treatment and calcium addition to milk with pH values between 6.6 and 5.6, will produce calcium milk gels with unique...... to be formed. In addition the low amount of micellar calcium caused a more compact gel structure with many protein aggregates. The results of this study highlighted the importance of calcium for the formation of acid, calcium and rennet gels. The content and the interactions of calcium with proteins during...

  10. Tunable Gas Sensing Gels by Cooperative Assembly.

    Science.gov (United States)

    Hussain, Abid; Semeano, Ana T S; Palma, Susana I C J; Pina, Ana S; Almeida, José; Medrado, Bárbara F; Pádua, Ana C C S; Carvalho, Ana L; Dionísio, Madalena; Li, Rosamaria W C; Gamboa, Hugo; Ulijn, Rein V; Gruber, Jonas; Roque, Ana C A

    2017-07-19

    The cooperative assembly of biopolymers and small molecules can yield functional materials with precisely tunable properties. Here, the fabrication, characterization, and use of multicomponent hybrid gels as selective gas sensors are reported. The gels are composed of liquid crystal droplets self-assembled in the presence of ionic liquids, which further coassemble with biopolymers to form stable matrices. Each individual component can be varied and acts cooperatively to tune gels' structure and function. The unique molecular environment in hybrid gels is explored for supramolecular recognition of volatile compounds. Gels with distinct compositions are used as optical and electrical gas sensors, yielding a combinatorial response conceptually mimicking olfactory biological systems, and tested to distinguish volatile organic compounds and to quantify ethanol in automotive fuel. The gel response is rapid, reversible, and reproducible. These robust, versatile, modular, pliant electro-optical soft materials possess new possibilities in sensing triggered by chemical and physical stimuli.

  11. Research on pre-staining gel electrophoresis

    International Nuclear Information System (INIS)

    Zhong Ruibo; Liu Yushuang; Zhang Ping; Liu Jingran; Zhao Guofen; Zhang Feng

    2014-01-01

    Background: Gel electrophoresis is a powerful biochemical separation technique. Most biological molecules are completely transparent in the visible region of light, so it is necessary to use staining to show the results after gel electrophoresis, and the general steps of conventional staining methods are time-consuming. Purpose: We try to develop a novel approach to simplify the gel electrophoresis: Pre-Staining Gel Electrophoresis (PSGE), which can make the gel electrophoresis results monitored in real time. Methods: Pre-stain the protein samples with Coomassie Brilliant Blue (CBB) for 30 min before loading the sample into the gel well. Results and Conclusion: PSGE can be successfully used to analyze the binding efficiency of Bovine Serum Albumin (BSA) and amphiphilic polymer via chemical coupling and physical absorption, and the double PSGE also shows a great potential in bio-analytical chemistry. (authors)

  12. Self-Pumping Active Gel

    Science.gov (United States)

    Wu, Kun-Ta; Hishamunda, Jean Bernard; Fraden, Seth; Dogic, Zvonimir

    Isotropic active gels are the network which is consist of cross-linked building blocks and the structure of which changes randomly and isotropically with time. Dogic et. al. show that pairs of anti-parallel microtubules form extensile bundles, which merge, extend, and buckle. In an unconfined system, the dynamics of these bundles causes spontaneous turbulent-like flow driven by motion of microscopic molecular motors. We found that confining these active gels in a millimeter sized toroids causes a transition into a new dynamical state characterized by circulation currents persisting for hours until ATP is depleted. We show how toroid dimensions impact the properties of self-organized circular currents, how directions of circulation can be designed by engineering ratchet-shaped boundaries, and how circulations of connected toroids can be either synchronized or antisynchronized. Furthermore, we demonstrate that the flow rate in the circulation is independent of curvature and length of flow path. The flow rate persists for centimeters without decay, disregarding conventional pipe flow resistance. Such findings pave the path to self-pumping pipe transport and performing physical work with biological system.

  13. Microfluidics of soft granular gels

    Science.gov (United States)

    Nixon, Ryan; Bhattacharjee, Tapomoy; Sawyer, W. Gregory; Angelini, Thomas E.

    Microfluidic methods for encapsulating cells and particles typically involve drop making with two immiscible fluids. The main materials constraint in this approach is surface tension, creating inherent instability between the two fluids. We can eliminate this instability by using miscible inner and outer phases. This is achieved by using granular micro gels which are chemically miscible but physically do not mix. These microgels are yield stress materials, so they flow as solid plugs far from shear gradients, and fluidize where gradients are generated - near an injection nozzle for example. We have found that tuning the yield stress of the material by varying polymer concentration, device performance can be controlled. The solid like behavior of the gel allows us to produces infinitely stable jets that maintain their integrity and configuration over long distances and times. These properties can be combined and manipulated to produce discrete particulate bunches of an inner phase, flowing inside of an outer phase, well enough even to print a Morse code message suspended within flow chambers about a millimeter in diameter moving at millimeters a second.

  14. Stabilized aqueous gels and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Swanson, B.L.

    1978-08-29

    New improved aqueous gels, and methods of using same in contacting subterranean formations, are provided. The gels are prepared by gelling an aqueous brine having incorporated therein a water-soluble cellulose ether such as a carboxymethylcellulose (CMC), and are rendered more stable to decomposition by incorporating a sulfoalkylated tannin stabilizing agent, such as a sulfomethylated quebracho (SMQ), in the gel during the preparation thereof.

  15. Ionic liquid based multifunctional double network gel

    Science.gov (United States)

    Ahmed, Kumkum; Higashihara, Tomoya; Arafune, Hiroyuki; Kamijo, Toshio; Morinaga, Takashi; Sato, Takaya; Furukawa, Hidemitsu

    2015-04-01

    Gels are a promising class of soft and wet materials with diverse application in tissue engineering and bio-medical purpose. In order to accelerate the development of gels, it is required to synthesize multi-functional gels of high mechanical strength, ultra low surface friction and suitable elastic modulus with a variety of methods and new materials. Among many types of gel ionic gel made from ionic liquids (ILs) could be used for diverse applications in electrochemical devices and in the field of tribology. IL, a promising materials for lubrication, is a salt with a melting point lower than 100 °C. As a lubricant, ILs are characterized by an extremely low vapor pressure, high thermal stability and high ion conductivity. In this work a novel approach of making double network DN ionic gel using IL has been made utilizing photo polymerization process. A hydrophobic monomer Methyl methacrylate (MMA) has been used as a first network and a hydrophobic IL monomer, N,N-diethyl-N-(2-mthacryloylethyl)-N-methylammonium bistrifluoromethylsulfonyl)imide (DEMM-TFSI) has been used as a second network using photo initiator benzophenon and crosslinker triethylene glycol dimethacrylate (TEGDMA). The resulting DN ionic gel shows transparency, flexibility, high thermal stability, good mechanical toughness and low friction coefficient value which can be a potential candidate as a gel slider in different mechanical devices and can open a new area in the field of gel tribology.

  16. Gel catalysts that switch on and off

    Science.gov (United States)

    Wang, Guoqiang; Kuroda, Kenichi; Enoki, Takashi; Grosberg, Alexander; Masamune, Satoru; Oya, Taro; Takeoka, Yukikazu; Tanaka, Toyoichi

    2000-01-01

    We report development of a polymer gel with a catalytic activity that can be switched on and off when the solvent composition is changed. The gel consists of two species of monomers. The major component, N-isopropylacrylamide, makes the gel swell and shrink in response to a change in composition of ethanol/water mixtures. The minor component, vinylimidazole, which is capable of catalysis, is copolymerized into the gel network. The reaction rate for catalytic hydrolysis of p-nitrophenyl caprylate was small when the gel was swollen. In contrast, when the gel was shrunken, the reaction rate increased 5 times. The activity changes discontinuously as a function of solvent composition, thus the catalysis can be switched on and off by an infinitesimal change in solvent composition. The kinetics of catalysis by the gel in the shrunken state is well described by the Michaelis–Menten formula, indicating that the absorption of the substrate by the hydrophobic environment created by the N-isopropylacrylamide polymer in the shrunken gel is responsible for enhancement of catalytic activity. In the swollen state, the rate vs. active site concentration is linear, indicating that the substrate absorption is not a primary factor determining the kinetics. Catalytic activity of the gel is studied for substrates with various alkyl chain lengths; of those studied the switching effect is most pronounced for p-nitrophenyl caprylate. PMID:10954747

  17. Conducting polymer electrodes for gel electrophoresis.

    Directory of Open Access Journals (Sweden)

    Katarina Bengtsson

    Full Text Available In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that π-conjugated polymers such as poly(3,4-ethylenedioxythiophene (PEDOT can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis systems. In this report, we extend our previous result to gel electrophoresis, and show that electrodes containing PEDOT can be used with a commercial polyacrylamide gel electrophoresis system with minimal impact to the resulting gel image or the ionic transport measured during a separation.

  18. Conducting polymer electrodes for gel electrophoresis.

    Science.gov (United States)

    Bengtsson, Katarina; Nilsson, Sara; Robinson, Nathaniel D

    2014-01-01

    In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that π-conjugated polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis) systems. In this report, we extend our previous result to gel electrophoresis, and show that electrodes containing PEDOT can be used with a commercial polyacrylamide gel electrophoresis system with minimal impact to the resulting gel image or the ionic transport measured during a separation.

  19. Preparation of continuous alumina gel fibres by aqueous sol–gel ...

    Indian Academy of Sciences (India)

    sol–gel process using aluminum-tri-isopropoxide as starting materials, and Shojaie-Bahaabad et al (2008) synthesized composite fibres (YAG/Al2O3) from an aqueous solution of aluminum powder, aluminum chloride hexahydrate and yttrium oxide by the sol–gel method. But, the preparation processes of continuous gel ...

  20. Topological characteristics of model gels

    International Nuclear Information System (INIS)

    Miller, Mark A; Hansen, Jean-Pierre; Blaak, Ronald

    2010-01-01

    The Euler characteristic of an object is a topological invariant determined by the number of handles and holes that it contains. Here, we use the Euler characteristic to profile the topology of model three-dimensional gel-forming fluids as a function of increasing length scale. These profiles act as a 'topological fingerprint' of the structure, and can be interpreted in terms of three types of topological events. As model fluids we have considered a system of dipolar dumbbells, and suspensions of adhesive hard spheres with isotropic and patchy interactions in turn. The correlation between the percolation threshold and the length scale on which the Euler characteristic passes through zero is examined and found to be system-dependent. A scheme for the efficient calculation of the Euler characteristic with and without periodic boundary conditions is described.

  1. Chitosan: Gels and Interfacial Properties

    Directory of Open Access Journals (Sweden)

    Julie Nilsen-Nygaard

    2015-03-01

    Full Text Available Chitosan is a unique biopolymer in the respect that it is abundant, cationic, low-toxic, non-immunogenic and biodegradable. The relative occurrence of the two monomeric building units (N-acetyl-glucosamine and d-glucosamine is crucial to whether chitosan is predominantly an ampholyte or predominantly a polyelectrolyte at acidic pH-values. The chemical composition is not only crucial to its surface activity properties, but also to whether and why chitosan can undergo a sol–gel transition. This review gives an overview of chitosan hydrogels and their biomedical applications, e.g., in tissue engineering and drug delivery, as well as the chitosan’s surface activity and its role in emulsion formation, stabilization and destabilization. Previously unpublished original data where chitosan acts as an emulsifier and flocculant are presented and discussed, showing that highly-acetylated chitosans can act both as an emulsifier and as a flocculant.

  2. Using Greener Gels to Explore Rheology

    Science.gov (United States)

    Garrett, Brendan; Matharu, Avtar S.; Hurst, Glenn A.

    2017-01-01

    A laboratory experiment was developed to investigate the rheological properties of a green calcium-cross-linked alginate gel as an alternative to the traditional borax-cross-linked poly(vinyl alcohol) gel. As borax is suspected of damaging fertility and the unborn child, a safe, green alternative is necessary. The rheological properties of a…

  3. nanocomposite hydrogels with high gel strength

    Indian Academy of Sciences (India)

    used in many fields such as hygienic products,1 agriculture,2,3 waste water treatment,4,5 drug-delivery systems6– ... commercially synthesized hectorite product was used to prepare NC gels by inverse microemulsion poly- ... 2.4 Gel strength evaluation of the nanocomposite hydrogels. The apparent viscosity was a relative ...

  4. Sodium Dedecyl Suphate Polyacrilamide Gel Electrophosis of ...

    African Journals Online (AJOL)

    Sodium Dedecyl Suphate Polyacrilamide Gel Electrophosis of Campylobacter coli. S.I. Smith, M.M. Ibrahim, V.N. Ezeobi, K.S. Oyedeji, K.A. Akinsinde, A.O Coker. Abstract. Campylobacter coli were characterized using sodium dodecyl sulphate-polyacrilamide gel electrophoresis (SDS-PAGE). The isolates were obtained ...

  5. Serum release boosts sweetness intensity in gels

    NARCIS (Netherlands)

    Sala, G.; Stieger, M.A.; Velde, van de F.

    2010-01-01

    This paper describes the effect of serum release on sweetness intensity in mixed whey protein isolate/gellan gum gels. The impact of gellan gum and sugar concentration on microstructure, permeability, serum release and large deformation properties of the gels was determined. With increasing gellan

  6. Nondenaturing agarose gel electrophoresis of RNA.

    Science.gov (United States)

    Rio, Donald C; Ares, Manuel; Hannon, Gregory J; Nilsen, Timothy W

    2010-06-01

    INTRODUCTION Perhaps the most important and certainly the most often used technique in RNA analysis is gel electrophoresis. Because RNAs are negatively charged, they migrate toward the anode in the presence of electric current. The gel acts as a sieve to selectively impede the migration of the RNA in proportion to its mass, given that its mass is generally proportional to its charge. Because mass is approximately related to chain length, the length of an RNA is more generally determined by its migration. In addition, topology (i.e., circularity) can affect migration, making RNAs appear longer on the gel than they actually are. There are two common types of gel: polyacrylamide and agarose. For most applications involving RNAs of or =600 nucleotides, and are especially useful for analysis of mRNAs (e.g., by Northern blotting). RNA analysis on agarose gels is essentially identical to DNA analysis (except that the gel boxes used must be dedicated to RNA work or to other ribonuclease-free work). Here we describe the use of straightforward Tris borate, EDTA (TBE) gels for routine analysis. These gels are appropriate for determining the quantity and integrity of RNA before using it for other applications. This procedure should not be used to determine size with accuracy, because the RNA will not remain in its extended state throughout the run.

  7. Fast Processing of Sol-Gel TCO

    NARCIS (Netherlands)

    Deelen, J. van; Rem, M.; Arfsten, N.; Buskens, P.P.

    2016-01-01

    TCOs are usually deposited using sputtering or chemical vapor deposition, which have a yield of typically 50-75%. The sol gel method does not need low pressure and can be done with a high precursor yield in the range of 90 – 100%. Sol gel enables also the TCO function as a planarization or

  8. Recrystallization of amylopectin in concentrated starch gels

    NARCIS (Netherlands)

    Keetels, CJAM; Oostergetel, GT; vanVliet, T

    The relation between the recrystallization of amylopectin and the increase in stiffness of starch gels during storage was studied by various techniques. From transmission electron microscopy it was concluded that the size of the crystalline domains in retrograded 30% w/w potato starch gels was about

  9. Silica gel matrix immobilized Chlorophyta hydrodictyon africanum ...

    African Journals Online (AJOL)

    Chlorophyta hydrodictyon africanum was immobilized on a silica gel matrix to improve its mechanical properties. The algae-silica gel adsorbent was used for batch sorption studies of a cationic dye, methylene blue (MB). Optimum adsorption was obtained with a dosage of 0.8 g bio sorbent. Results from sorption studies ...

  10. Polymer architecture of magnetic gels: a review

    Science.gov (United States)

    Weeber, Rudolf; Hermes, Melissa; Schmidt, Annette M.; Holm, Christian

    2018-02-01

    In this review article, we provide an introduction to ferrogels, i.e. polymeric gels with embedded magnetic particles. Due to the interplay between magnetic and elastic properties of these materials, they are promising candidates for engineering and biomedical applications such as actuation and controlled drug release. Particular emphasis will be put on the polymer architecture of magnetic gels since it controls the degrees of freedom of the magnetic particles in the gel, and it is important for the particle-polymer coupling determining the mechanisms available for the gel deformation in magnetic fields. We report on the different polymer architectures that have been realized so far, and provide an overview of synthesis strategies and experimental techniques for the characterization of these materials. We further focus on theoretical and simulational studies carried out on magnetic gels, and highlight their contributions towards understanding the influence of the gels’ polymer architecture.

  11. On shear rheology of gel propellants

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, Shai; Peretz, Arie [RAFAEL, MANOR Propulsion and Explosive Systems Division, Haifa (Israel); Natan, Benveniste [Faculty of Aerospace Engineering, Technion - Israel Institute of Technology, Haifa (Israel)

    2007-04-15

    Selected fuel, oxidizer and simulant gels were prepared and rheologically characterized using a rotational rheometer. For fuel gelation both organic and inorganic gellants were utilized, whereas oxidizers and simulants were gelled with addition of silica and polysaccharides, respectively. The generalized Herschel-Bulkley constitutive model was found to most adequately represent the gels studied. Hydrazine-based fuels, gelled with polysaccharides, were characterized as shear-thinning pseudoplastic fluids with low shear yield stress, whereas inhibited red-fuming nitric acid (IRFNA) and hydrogen peroxide oxidizers, gelled with silica, were characterized as yield thixotropic fluids with significant shear yield stress. Creep tests were conducted on two rheological types of gels with different gellant content and the results were fitted by Burgers-Kelvin viscoelastic constitutive model. The effect of temperature on the rheological properties of gel propellant simulants was also investigated. A general rheological classification of gel propellants and simulants is proposed. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  12. FTIR thermal analysis on organofunctionalized silica gel

    Directory of Open Access Journals (Sweden)

    Foschiera José L.

    2001-01-01

    Full Text Available Silica gel modified with organic groups is widely used as a stationary phase for liquid chromatography. Grafting synthesis can be used to obtain stable modified silica gel surfaces. In this work, silica gel (10 nm of pore diameter and surface area of 320 m² g-1 was chemically modified with 3-chloropropyltrimethoxysilane or 3-aminopropyltrimethoxysilane and reacted with aniline, p-anisidine, benzylamine and 3-phenylpropylchloride in order to yield aromatic groups immobilized on the silica gel surface. Infrared spectroscopy was utilized for characterization of the aromatic groups grafted on the silica gel surface, using a quartz cell. The solids were heated at several temperatures in high vacuum and the infrared band areas of the organic groups were used to evaluate the thermal stability.

  13. Recent Advances in Supramolecular Gels and Catalysis.

    Science.gov (United States)

    Fang, Weiwei; Zhang, Yang; Wu, Jiajie; Liu, Cong; Zhu, Haibo; Tu, Tao

    2018-04-04

    Over the past two decades, supramolecular gels have attracted significant attention from scientists in diverse research fields and have been extensively developed. This review mainly focuses on the significant achievements in supramolecular gels and catalysis. First, by incorporating diverse catalytic sites and active organic functional groups into gelator molecules, supramolecular gels have been considered as a novel matrix for catalysis. In addition, these rationally designed supramolecular gels also provide a variety of templates to access metal nanocomposites, which may function as catalysts and exhibit high activity in diverse catalytic transformations. Finally, as a new kind of biomaterial, supramolecular gels formed in situ by self-assembly triggered by catalytic transformations are also covered herein. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Gelatin increases the coarseness of whey protein gels and impairs water exudation from the mixed gel at low temperatures

    NARCIS (Netherlands)

    Martin, A.H.; Bakhuizen, E.; Ersch, C.; Urbonaite, V.; Jongh, H.H.J. de; Pouvreau, L.

    2016-01-01

    To understand the origin of water holding of mixed protein gels, a study was performed on water exudation from mixed whey protein (WP)-gelatin gels upon applied pressure. Mixed gels were prepared with varying WP and gelatin concentration and gelatin type to obtain gels with a wide range of gel

  15. Internal structure analysis of particle-double network gels used in a gel organ replica

    Science.gov (United States)

    Abe, Mei; Arai, Masanori; Saito, Azusa; Sakai, Kazuyuki; Kawakami, Masaru; Furukawa, Hidemitsu

    2016-04-01

    In recent years, the fabrication of patient organ replicas using 3D printers has been attracting a great deal of attention in medical fields. However, the cost of these organ replicas is very high as it is necessary to employ very expensive 3D printers and printing materials. Here we present a new gel organ replica, of human kidney, fabricated with a conventional molding technique, using a particle-double network hydrogel (P-DN gel). The replica is transparent and has the feel of a real kidney. It is expected that gel organ replicas produced this way will be a useful tool for the education of trainee surgeons and clinical ultrasonography technologists. In addition to developing a gel organ replica, the internal structure of the P-DN gel used is also discussed. Because the P-DN gel has a complex structure comprised of two different types of network, it has not been possible to investigate them internally in detail. Gels have an inhomogeneous network structure. If it is able to get a more uniform structure, it is considered that this would lead to higher strength in the gel. In the present study we investigate the structure of P-DN gel, using the gel organ replica. We investigated the internal structure of P-DN gel using Scanning Microscopic Light Scattering (SMILS), a non-contacting and non-destructive.

  16. Sol-gel bonding of silicon wafers

    International Nuclear Information System (INIS)

    Barbe, C.J.; Cassidy, D.J.; Triani, G.; Latella, B.A.; Mitchell, D.R.G.; Finnie, K.S.; Short, K.; Bartlett, J.R.; Woolfrey, J.L.; Collins, G.A.

    2005-01-01

    Sol-gel bonds have been produced between smooth, clean silicon substrates by spin-coating solutions containing partially hydrolysed silicon alkoxides. The two coated substrates were assembled and the resulting sandwich fired at temperatures ranging from 60 to 600 deg. C. The sol-gel coatings were characterised using attenuated total reflectance Fourier transform infrared spectroscopy, ellipsometry, and atomic force microscopy, while the corresponding bonded specimens were investigated using scanning electron microscopy and cross-sectional transmission electron microscopy. Mechanical properties were characterised using both microindentation and tensile testing. Bonding of silicon wafers has been successfully achieved at temperatures as low as 60 deg. C. At 300 deg. C, the interfacial fracture energy was 1.55 J/m 2 . At 600 deg. C, sol-gel bonding provided superior interfacial fracture energy over classical hydrophilic bonding (3.4 J/m 2 vs. 1.5 J/m 2 ). The increase in the interfacial fracture energy is related to the increase in film density due to the sintering of the sol-gel interface with increasing temperature. The superior interfacial fracture energy obtained by sol-gel bonding at low temperature is due to the formation of an interfacial layer, which chemically bonds the two sol-gel coatings on each wafer. Application of a tensile stress on the resulting bond leads to fracture of the samples at the silicon/sol-gel interface

  17. Calcium Impact on Milk Gels Formation

    DEFF Research Database (Denmark)

    Koutina, Glykeria

    enriched dairy products. Calcium gels can be produced by addition of a calcium salt and heat treatment at temperatures higher than 70 oC for several minutes. The combination of heat treatment and calcium addition to milk with pH values between 6.6 and 5.6, will produce calcium milk gels with unique...... and dense gel structure and with little seperation of whey due to participation of calcium to the final gel structure. On the other hand, the combination of heat treatment and calcium addition to milk with pH values lower than 5.6 will still produce gel structures which are dominated by the decrease of p...... to be formed. In addition the low amount of micellar calcium caused a more compact gel structure with many protein aggregates. The results of this study highlighted the importance of calcium for the formation of acid, calcium and rennet gels. The content and the interactions of calcium with proteins during...

  18. Application of melanin-free ink as a new antioxidative gel enhancer in sardine surimi gel.

    Science.gov (United States)

    Vate, Naveen Kumar; Benjakul, Soottawat; Agustini, Tri Winarni

    2015-08-30

    The squid ink that is discarded as waste during processing can be effectively utilised as a gel enhancer in surimi gels, especially those prepared from dark-fleshed fish which have poor gel properties. It also acts as an antioxidant, inhibiting lipid oxidation. This investigation aimed to study the effect of melanin-free ink (MFI) from splendid squid (Loligo formosana) on properties and oxidative stability of surimi gel from sardine (Sardinella albella). MFI (0-0.1 g kg(-1) surimi) increased the breaking force and deformation of sardine surimi gel in a dose-dependent manner (P 0.05). The expressible moisture content of gels decreased as the levels of MFI increased (P < 0.05). Based on a microstructure study, gel added with MFI at a level of 0.08 g kg(-1) surimi was denser and finer than that of the control (without MFI). Surimi gels with MFI had lower peroxide values, thiobarbituric acid reactive substances, nonanal and 2-decenal. MFI could improve the properties of sardine surimi gel. Additionally, it was able to prevent lipid oxidation in surimi gels during refrigerated storage. © 2014 Society of Chemical Industry.

  19. Simple and practical staining of DNA with GelRed in agarose gel electrophoresis.

    Science.gov (United States)

    Huang, Qing; Baum, Larry; Fu, Wei-Ling

    2010-01-01

    Although SYBR Gold or SYBR Green I have been used in the loading buffer as a DNA stain safer than ethidium bromide for agarose gel electrophoresis, electrophoretic mobility of DNA is altered and thus DNA fragment size cannot be accurately determined. A method using GelRed in the loading buffer was developed to stain DNA fragments in agarose gel electrophoresis. Among various concentrations of GelRed, SYBR Gold, or SYBR Green I tested in the loading buffer, only the highest tested concentration of GelRed, i.e., 100x GelRed, did not change band mobility. Evaluations using various sizes of PCR products at different concentrations further confirmed that 100x GelRed could be used to accurately determine DNA fragment size. The reagent can be stored at 4 degrees C for at least 1 year without a decrease in staining sensitivity. The 100x GelRed is a sensitive and safe alternative to ethidium bromide and better than either SYBR Gold or SYBR Green I for size determination in agarose gel electrophoresis. Our laboratory now uses the GelRed method routinely with great consistency and success.

  20. Pulsed field gel electrophoresis a practical guide

    CERN Document Server

    Birren, Bruce

    1993-01-01

    Pulsed Field Gel Electrophoresis: A Practical Guide is the first laboratory manual to describe the theory and practice of this technique. Based on the authors' experience developing pulsed field gel instruments and teaching procedures, this book provides everything a researcher or student needs to know in order to understand and carry out pulsed field gel experiments. Clear, well-tested protocols assume only that users have a basic familiarity with molecular biology. Thorough coverage of useful data, theory, and applications ensures that this book is also a lasting resource for more adv

  1. Exopolysaccharide influence on acid gel formation

    Directory of Open Access Journals (Sweden)

    K. Yoanidu

    2017-06-01

    Full Text Available Abstract. Turbidimetric monitoring of milk coagulation was conducted in situ. Milk gel was produced by acidification with the use of three strains of starter culture. These strains were characterized by various acidification rate and exopolysaccharides (EPS production. The concentrations of EPS affect mostly the pH of gel formation (5.53 - low EPS – producing strain; 5.33 - medium EPS – producing strain; 5.46 - high EPS – producing strain whereas the time of gel formation depends on the various rate of acidification of all three strains.

  2. Buckling of paramagnetic chains in soft gels.

    Science.gov (United States)

    Huang, Shilin; Pessot, Giorgio; Cremer, Peet; Weeber, Rudolf; Holm, Christian; Nowak, Johannes; Odenbach, Stefan; Menzel, Andreas M; Auernhammer, Günter K

    2016-01-07

    We study the magneto-elastic coupling behavior of paramagnetic chains in soft polymer gels exposed to external magnetic fields. To this end, a laser scanning confocal microscope is used to observe the morphology of the paramagnetic chains together with the deformation field of the surrounding gel network. The paramagnetic chains in soft polymer gels show rich morphological shape changes under oblique magnetic fields, in particular a pronounced buckling deformation. The details of the resulting morphological shapes depend on the length of the chain, the strength of the external magnetic field, and the modulus of the gel. Based on the observation that the magnetic chains are strongly coupled to the surrounding polymer network, a simplified model is developed to describe their buckling behavior. A coarse-grained molecular dynamics simulation model featuring an increased matrix stiffness on the surfaces of the particles leads to morphologies in agreement with the experimentally observed buckling effects.

  3. Evaluation of wheat by polyacrylamide gel electrophoresis

    African Journals Online (AJOL)

    PRECIOUS

    2010-01-11

    04, Inqulab-91 and Rawal-. 87 were evaluated for analysis of variability in seed storage proteins by using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Electrophorogram for each variety were scored ...

  4. Sodium Dedecyl Suphate Polyacrilamide Gel Electrophosis of ...

    African Journals Online (AJOL)

    polyacrilamide gel electrophoresis (SDS-PAGE). The isolates were obtained from the faeces of diarrhoeic children with the age range of 0 t 36 months attending paediatric clinic at the Lagos University Teaching Hospital (LUTH) and Obafemi Awolowo ...

  5. Preparation of zirconium molybdate gel generator

    International Nuclear Information System (INIS)

    Charoen, S.; Aungurarat, G.; Laohawilai, S.; Sukontpradit, W.; Jingjit, S.

    1994-01-01

    A procedure for preparation of 99mTc generator based on conversion to zirconium molybdate gel of 99Mo produced by neutron activation was reported. The gel was prepared from zirconium oxychloride solution pH 1.6, ammonium molybdate solution pH 3-5 and mole ratio of Zr:Mo 1:1 which had water content about 7-8%. Small generators containing 1-1.5 g of gel were eluted with average efficiencies of 77% and the activity peak in the first 3 ml of 10 ml of saline solution. The amount of Mo and Zr in eluates were below the acceptance limit. The gel generators of activity about 100 mCi were prepared and had the good performance in elutability and stability

  6. Thixotropic corrosive gels for nuclear decontamination

    International Nuclear Information System (INIS)

    Bargues, St.

    1998-01-01

    The aim of this thesis was the development of corrosive gels for metallic surface decontamination. These gels formulation, based on a powerful oxidant (the cerium IV), the nitric acid, a mineral charge (silica) and a non ionic surface-active, has been developed according to the specific constraints of the nuclear industry. The objective was to prepare thixotropic gels becoming liquid after shacking to allow an easy pulverization and coming again solid to permit a perfect adhesion on the metallic surface. This rheological study of the gels has been completed by an evaluation of their corrosive properties. The last part of the work presents an industrial utilization during two years. (A.L.B.)

  7. Detection of pectinesterase in polyacrylamide gels.

    Science.gov (United States)

    Alonso, J; Rodríguez, M T; Canet, W

    1995-01-01

    A rapid and sensitive method of detecting pectinesterase activity following electrophoresis or isoelectric focusing in polyacrylamide gels is described. The method uses ruthenium red and requires no addition of substrate when making the gels, thus obviating direct enzyme-substrate contact during electrophoresis. Because of its versatility, the method can be used in a wide variety of applications, such as plant and microbial taxonomy, enzyme purification and characterization, or as an analytical method in fresh and processed plant technology.

  8. Improving calibration accuracy in gel dosimetry

    International Nuclear Information System (INIS)

    Oldham, M.; McJury, M.; Webb, S.; Baustert, I.B.; Leach, M.O.

    1998-01-01

    A new method of calibrating gel dosimeters (applicable to both Fricke and polyacrylamide gels) is presented which has intrinsically higher accuracy than current methods, and requires less gel. Two test-tubes of gel (inner diameter 2.5 cm, length 20 cm) are irradiated separately with a 10x10cm 2 field end-on in a water bath, such that the characteristic depth-dose curve is recorded in the gel. The calibration is then determined by fitting the depth-dose measured in water, against the measured change in relaxivity with depth in the gel. Increased accuracy is achieved in this simple depth-dose geometry by averaging the relaxivity at each depth. A large number of calibration data points, each with relatively high accuracy, are obtained. Calibration data over the full range of dose (1.6-10 Gy) is obtained by irradiating one test-tube to 10 Gy at dose maximum (D max ), and the other to 4.5 Gy at D max . The new calibration method is compared with a 'standard method' where five identical test-tubes of gel were irradiated to different known doses between 2 and 10 Gy. The percentage uncertainties in the slope and intercept of the calibration fit are found to be lower with the new method by a factor of about 4 and 10 respectively, when compared with the standard method and with published values. The gel was found to respond linearly within the error bars up to doses of 7 Gy, with a slope of 0.233±0.001 s -1 Gy -1 and an intercept of 1.106±0.005 Gy. For higher doses, nonlinear behaviour was observed. (author)

  9. Conducting Polymer Electrodes for Gel Electrophoresis

    OpenAIRE

    Bengtsson, Katarina; Nilsson, Sara; Robinson, Nathaniel D

    2014-01-01

    In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that p-conjugated polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis) systems. In this report, we extend our previous result to gel ...

  10. Cumulative irritation comparison of adapalene gel and solution with 2 tazarotene gels and 3 tretinoin formulations.

    Science.gov (United States)

    Greenspan, Alan; Loesche, Christian; Vendetti, Nancy; Georgeian, Kathleen; Gilbert, Richard; Poncet, Michel; Baker, Michael D; Soto, Pascale

    2003-07-01

    Forty-two subjects with normal skin were enrolled in a single-center study to assess the cumulative irritancy potential of adapalene (Differin gel 0.1% and Differin solution 0.1%) compared with tazarotene (Tazorac gels 0.05% and 0.1%), tretinoin (Retin-A Micro gel 0.1%, Avita cream 0.025%, and Avita gel 0.025%), and white petrolatum (negative control). All test materials were applied randomly, under occlusion, to sites located on either side of the midline--the mid thoracic area of the subjects' backs. All patches were applied daily, Monday through Friday, to the same sites, unless the degree of reaction to a test product or adhesive necessitated removal (grade 3). Thirty-eight of the 42 subjects (90.5%) completed the study. Thirty-four of those 38 subjects (89.5%) had to discontinue using both tazarotene concentrations due to intolerance. Patch discontinuations for the remaining test materials were as follows: 7 subjects discontinued use of tretinoin microsphere gel 0.1%, 3 discontinued tretinoin cream 0.025%, 1 discontinued tretinoin gel 0.025%, and 1 discontinued adapalene gel 0.1%. None of the subjects discontinued use of the white petrolatum or the adapalene solution 0.1%. Adapalene gel and solution 0.1% were statistically (P<.01) less irritating than both tazarotene gels 0.1% and 0.05%, tretinoin microsphere gel 0.1%, and tretinoin gel 0.025%, and they were not statistically different from tretinoin gel 0.025%.

  11. Study of nuclear glasses alteration gel and synthesis of some model gels; Etude du gel d`alteration des verres nucleaires et synthese de gels modeles

    Energy Technology Data Exchange (ETDEWEB)

    Ricol, S.

    1995-10-05

    This work deals with the general problem of alteration of the reference nuclear glass R7T7. Attention is paid particularly to the altered layer formed at the glass surface during alteration process. In opposition to previous works, related essentially to glass dissolution kinetics based on chemical analyses of lixiviated elements, this thesis deals with alteration problems through structural studies of the reference glass and derived gel. This approach allows the determination of mechanisms for the gel formation and a better understanding of the behaviour of glasses towards lixiviation. Both approaches appeared complementary. Based on several spectroscopic techniques, this work showed the particular role of cations such as calcium, zirconium and iron. Studies of silica-based synthetic gels showed the synergic effect of formers cation and of one highly coordinated cation. The variation of the wavenumber related to Si-O-Si asymmetric stretching vibration can be correlated to O/Si ratio for ternary systems Si/Na/Zr. On the contrary, the Si losses of the materials depend on the number of non-bridging oxygen atoms. In the perspective of long-term behaviour, the alteration gel presents better characteristics than initial glass. It is therefore a highly stable material in static conditions. In the same way, synthetic gels are materials with very low solubilities (much lower than the alteration gel) and could be used as confining matrices. (authors). refs., 71 figs., 37 tabs.

  12. Polymeric gels for intravaginal drug delivery.

    Science.gov (United States)

    Cook, Michael T; Brown, Marc B

    2018-01-28

    Intravaginal drug delivery can elicit a local effect, or deliver drugs systemically without hepatic first pass metabolism. There are a number of emerging areas in intravaginal drug delivery, but the vagina is a challenging route of administration, due to the clearance mechanisms present which result in poor retention of dosage forms, and the potential for irritation and other adverse reactions. Gel formulations are desirable due to the ease of application, spreading and that they cause little to no discomfort to the patient. However, these dosage forms, in particular, are poorly retained and traditional gels typically have little control over drug release rates. This has led to a large number of studies on improving the retention of vaginal gels and modulating the controlled release of drugs from the gel matrix. This review outlines the anatomy and physiology of the vagina, focussing on areas relevant to drug delivery. Medical applications of vaginally administered medicines is then discussed, followed by an overview of polymeric gels in intravaginal drug delivery. The sensorial properties of intravaginal gels, and how these relate to user compliance are also summarised. Finally, some important barriers to marketing approval are described. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Basic investigations on LCV micelle gel

    Science.gov (United States)

    Ebenezer, S. B.; Rafic, M. K.; Ravindran, P. B.

    2013-06-01

    The aim of this study was to investigate the feasibility of using Leuco Crystal Violet (LCV) based micelle gel dosimeter as a quality assurance tool in radiotherapy applications. Basic properties such as absorption coefficient and diffusion of LCV gel phantom over time were evaluated. The gel formulation consisted of 25 mM Trichloroacetic acid, 1mM LCV, 4 mM Triton X-100, 4% gelatin by mass and distilled water. The advantages of using this gel are its tissue equivalence, easy and less preparation time, lower diffusion rate and it can be read with an optical scanner. We were able to reproduce some of the results of Babic et al. The peak absorption was found to be at 600 nm and hence a matrix of yellow LEDs was used as light source. The profiles obtained from projection images confirmed the diffusion of LCV gel after 6 hours of irradiation. Hence the LCV gel phantom should be read before 6 hours post irradiation to get accurate dose information as suggested previously.

  14. Gel nano-particulates against radioactivity; Des nanoparticules en gel contre la radioactivite

    Energy Technology Data Exchange (ETDEWEB)

    Deroin, Ph

    2004-11-01

    The Argonne research center (USA) has developed a 'super-gel' compound, a polymer close to those used in baby's diapers, which can reach a 90% efficiency in the radioactive decontamination of porous materials, like bricks or concrete. The contaminated materials are sprayed with a mixture of polymer gel and wetting agent with nano-particulates in suspension. Under the action of the wetting agent, radioactivity migrates from the pores to the gel and is trapped by the nano-particulates. The drying and recycling of the gel allows to reduce the volume of radioactive wastes. Short paper. (J.S.)

  15. Evolution of gel structure during thermal processing of Na-geopolymer gels.

    Science.gov (United States)

    Duxson, Peter; Lukey, Grant C; van Deventer, Jannie S J

    2006-10-10

    The present work examines how the gel structure and phase composition of Na-geopolymers derived from metakaolin with varied Si/Al ratio evolve with exposure to temperatures up to 1000 degrees C. Gels were thermally treated and characterized using quantitative XRD, DTA, and FTIR to elucidate the changes in gel structure, phase composition, and porosity at each stage of heating. It is found that the phase stability, defined by the amount and onset temperature of crystallization, is improved at higher Si/Al ratios. Two different mechanisms of densification have been isolated by FTIR, related to viscous flow and collapse of the highly distributed pore network in the gel. Gels with low Si/Al ratio only experience viscous flow that correlates with low thermal shrinkage. Gels at a higher Si/Al ratio, which have a homogeneous microstructure composed of a highly distributed porosity, undergo both densification processes corresponding to a large extent of thermal shrinkage during densification. This work elucidates the intimate relationship between gel microstructure, chemistry, and thermal evolution of Na-geopolymer gels.

  16. Physical and chemical properties of gels. Application to protein nucleation control in the gel acupuncture technique

    Science.gov (United States)

    Moreno, Abel; Juárez-Martínez, Gabriela; Hernández-Pérez, Tomás; Batina, Nikola; Mundo, Manuel; McPherson, Alexander

    1999-09-01

    In this work, we present a new approach using analytical and optical techniques in order to determine the physical and chemical properties of silica gel, as well as the measurement of the pore size in the network of the gel by scanning electron microscopy. The gel acupuncture technique developed by García-Ruiz et al. (Mater. Res. Bull 28 (1993) 541) García-Ruiz and Moreno (Acta Crystallogr. D 50 (1994) 484) was used throughout the history of crystal growth. Several experiments were done in order to evaluate the nucleation control of model proteins (thaumatin I from Thaumatococcus daniellii, lysozyme from hen egg white and catalase from bovine liver) by the porous network of the gel. Finally, it is shown how the number and the size of the crystals obtained inside X-ray capillaries is controlled by the size of the porous structure of the gel.

  17. Mucosal effects of tenofovir 1% gel.

    Science.gov (United States)

    Hladik, Florian; Burgener, Adam; Ballweber, Lamar; Gottardo, Raphael; Vojtech, Lucia; Fourati, Slim; Dai, James Y; Cameron, Mark J; Strobl, Johanna; Hughes, Sean M; Hoesley, Craig; Andrew, Philip; Johnson, Sherri; Piper, Jeanna; Friend, David R; Ball, T Blake; Cranston, Ross D; Mayer, Kenneth H; McElrath, M Juliana; McGowan, Ian

    2015-02-03

    Tenofovir gel is being evaluated for vaginal and rectal pre-exposure prophylaxis against HIV transmission. Because this is a new prevention strategy, we broadly assessed its effects on the mucosa. In MTN-007, a phase-1, randomized, double-blinded rectal microbicide trial, we used systems genomics/proteomics to determine the effect of tenofovir 1% gel, nonoxynol-9 2% gel, placebo gel or no treatment on rectal biopsies (15 subjects/arm). We also treated primary vaginal epithelial cells from four healthy women with tenofovir in vitro. After seven days of administration, tenofovir 1% gel had broad-ranging effects on the rectal mucosa, which were more pronounced than, but different from, those of the detergent nonoxynol-9. Tenofovir suppressed anti-inflammatory mediators, increased T cell densities, caused mitochondrial dysfunction, altered regulatory pathways of cell differentiation and survival, and stimulated epithelial cell proliferation. The breadth of mucosal changes induced by tenofovir indicates that its safety over longer-term topical use should be carefully monitored.

  18. Comparative Two-Dimensional Fluorescence Gel Electrophoresis.

    Science.gov (United States)

    Ackermann, Doreen; König, Simone

    2018-01-01

    Two-dimensional comparative fluorescence gel electrophoresis (CoFGE) uses an internal standard to increase the reproducibility of coordinate assignment for protein spots visualized on 2D polyacrylamide gels. This is particularly important for samples, which need to be compared without the availability of replicates and thus cannot be studied using differential gel electrophoresis (DIGE). CoFGE corrects for gel-to-gel variability by co-running with the sample proteome a standardized marker grid of 80-100 nodes, which is formed by a set of purified proteins. Differentiation of reference and analyte is possible by the use of two fluorescent dyes. Variations in the y-dimension (molecular weight) are corrected by the marker grid. For the optional control of the x-dimension (pI), azo dyes can be used. Experiments are possible in both vertical and horizontal (h) electrophoresis devices, but hCoFGE is much easier to perform. For data analysis, commercial software capable of warping can be adapted.

  19. DNA DAMAGE QUANTITATION BY ALKALINE GEL ELECTROPHORESIS.

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Elasticity and clustering in concentrated depletion gels.

    Science.gov (United States)

    Ramakrishnan, S; Chen, Y-L; Schweizer, K S; Zukoski, C F

    2004-10-01

    X-ray scattering and rheology are employed to study the volume fraction dependence of the collective structure and elastic moduli of concentrated nanoparticle-polymer depletion gels. The nonequilibrium gel structure consists of locally densified nonfractal clusters and narrow random interfaces. The elastic moduli display a power law dependence on volume fraction with effective exponents that decrease with increasing depletion attraction strength. A microscopic theory that combines local structural information with a dynamic treatment of gelation is in good agreement with the observations.

  1. Pouring and running a protein gel by reusing commercial cassettes.

    Science.gov (United States)

    Hwang, Alexander C; Grey, Paris H; Cuddy, Katrina; Oppenheimer, David G

    2012-02-12

    The evaluation of proteins using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis is a common technique used by biochemistry and molecular biology researchers. For laboratories that perform daily analyses of proteins, the cost of commercially available polyacrylamide gels (~$10/gel) can be considerable over time. To mitigate this cost, some researchers prepare their own polyacrylamide gels. Traditional methods of pouring these gels typically utilize specialized equipment and glass gel plates that can be expensive and preclude pouring many gels and storing them for future use. Furthermore, handling of glass plates during cleaning or gel pouring can result in accidental breakage creating a safety hazard, which may preclude their use in undergraduate laboratory classes. Our protocol demonstrates how to pour multiple protein gels simultaneously by recycling Invitrogen Nupage Novex minigel cassettes, and inexpensive materials purchased at a home improvement store. This economical and streamlined method includes a way to store the gels at 4°C for a few weeks. By re-using the plastic gel cassettes from commercially available gels, labs that run frequent protein gels can save significant costs and help the environment. In addition, plastic gel cassettes are extremely resistant to breakage, which makes them ideal for undergraduate laboratory classrooms.

  2. Eliminating blurry bands in gels with a simple cost-effective repair to the gel cassette.

    Science.gov (United States)

    Bingaman, Jamie L; Frankel, Erica A; Hull, Chelsea M; Leamy, Kathleen A; Messina, Kyle J; Mitchell, David; Park, Hongmarn; Ritchey, Laura E; Babitzke, Paul; Bevilacqua, Philip C

    2016-12-01

    Gel electrophoresis and subsequent imaging using phosphorimagers is one of the most important and widely used techniques in RNA and DNA analysis. Radiolabeling nucleic acids with 32 P and detecting bands using a phoshorimager are useful both in a qualitative sense for nucleic acid detection and in a quantitative sense for structural, kinetic, or binding-based assays. Because of this, good resolution of gel bands based on molecular weight and size of RNA or DNA is essential for analysis. The appearance of blurry gel bands of 32 P-labeled RNA and DNA thus represents a serious problem in the laboratory. A quick search on the Internet uncovers numerous reports begrudging the appearance of blurry bands, as well as attempts to fix them without success. Indeed, our laboratories were beset by the intermittent problem of blurry gels for over one year before we found a solution. Herein we describe a simple and cost-effective solution to a problem that we show originates from the phosphorimager cassettes rather than the integrity of the gel itself. We hope that the information provided here will lead to immediate help for other laboratories experiencing similar issues with labeled nucleic acid gel-based assays. The improvement in the clarity of the gels is nothing short of astonishing in many instances and will lead to higher resolution images for analysis and publications. © 2016 Bingaman et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  3. Tough Amphiphilic Gels for Antifouling Applications

    Science.gov (United States)

    Villada, Laura M.

    Biofouling is the attachment of unwanted organisms on a surface, and it is influenced by a host of variables including the chemistry of the material as well as both the surface and bulk properties, and controlling and understanding the effect of these properties is critical for the development of effective materials to combat biofouling. All surfaces that are submerged in water are subject to the rapid colonization of a wide range of marine organisms. Marine biofouling decreases fuel efficiency, costing the Navy millions of dollars in penalty, as well as having drastic environmental effects. Previous prevention of biofouling in marine systems has been accomplished by the administration of biocides and toxic coatings. In recent years, increased concerns about the impacts of these hazardous compounds into marine ecosystems has spurred efforts to develop cost effective, non-toxic, and durable anti-fouling coatings. Hydrogels, hydrophilic crosslinked networks, are being used to modify silicone marine coatings and have demonstrated potential at combatting biofouling. Understanding the impact of amphiphilic materials, i.e. their structure and properties, on biofouling is of great importance in order to address the need in the industry. In this study, poly(2-hydroxyethyl methacrylate) (HEMA) crosslinked networks were tailored to investigate the influence of their surface and bulk properties on biofouling. Previous research utilizing HEMA-siloxane gels suggested a relationship between molecular weight between crosslinks, M c, and the attachment of soft fouling sporelings of the green algae U. linza and adsorption of the protein bovine serum albumin (BSA), and the initial thrust of this dissertation was aimed at resolving this relationship. Gel composition was modified by varying the siloxane crosslinking agent and the siloxane hydrophobic monomer concentrations. The gels exhibited an increase in elastic modulus from 0.17 to 8.55 MPa that coincided with an increasing

  4. Normoxic polymer gel - basic characterisation and clinical use

    International Nuclear Information System (INIS)

    Scheib, S G; Vogelsanger, W; Gianolini, S; Crescenti, R

    2004-01-01

    The formulation for a new polymer gel, which is made under normal atmospheric conditions, has been published. Because manufacturing and processing can be performed under normal atmospheric conditions, the gel is also called normoxic. Only a few accessories for gel production are necessary, facilitating the use of this gel, which can be easily produced in a clinical environment. The purpose of this study, which is work in progress, was to produce several gel batches with varying concentrations of their compounds, to measure dose response curves, to investigate ageing effects and to use this polymer gel in 3D absolute dose verifications in radiosurgery, IMRT and proton therapy

  5. Multiple-phase behavior and memory effect of polymer gel

    CERN Document Server

    Annaka, M; Nakahira, T; Sugiyama, M; Hara, K; Matsuura, T

    2002-01-01

    A poly(4-acrylamidosalicylic acid) gel (PASA gel) exhibits multiple phases as characterized by distinct degrees of swelling; the gel can take one of four different swelling values, but none of the intermediate values. The gel has remarkable memory: the phase behavior of the gel depends on whether the gel has experienced the most swollen phase or the most collapsed phase in the immediate past. The information is stored and reversibly erased in the form of a macroscopic phase transition behavior. The structure factors corresponding to these four phases were obtained by SANS, which indicated the presence of characteristic structures depending on pH and temperature, particularly in the shrunken state. (orig.)

  6. Protein electrophoretic migration data from custom and commercial gradient gels

    Directory of Open Access Journals (Sweden)

    Andrew J. Miller

    2016-12-01

    Full Text Available This paper presents data related to the article “A method for easily customizable gradient gel electrophoresis” (A.J. Miller, B. Roman, E.M. Norstrom, 2016 [1]. Data is presented on the rate of electrophoretic migration of proteins in both hand-poured and commercially acquired acrylamide gradient gels. For each gel, migration of 9 polypeptides of various masses was measured upon completion of gel electrophoresis. Data are presented on the migration of proteins within separate lanes of the same gel as well as migration rates from multiple gels.

  7. The mechanism and properties of acid-coagulated milk gels

    Directory of Open Access Journals (Sweden)

    Chanokphat Phadungath

    2005-03-01

    Full Text Available Acid-coagulated milk products such as fresh acid-coagulated cheese varieties and yogurt areimportant dairy food products. However, little is known regarding the mechanisms involved in gel formation, physical properties of acid gels, and the effects of processing variables such as heat treatment and gelation temperature on the important physical properties of acid milk gels. This paper reviews the modern concepts of possible mechanisms involved in the formation of particle milk gel aggregation, along with recent developments including the use of techniques such as dynamic low amplitude oscillatory rheology to observe the gel formation process, and confocal laser scanning microscopy to monitor gel microstructure.

  8. Initial investigation of a novel light-scattering gel phantom for evaluation of optical CT scanners for radiotherapy gel dosimetry

    International Nuclear Information System (INIS)

    Bosi, Stephen; Naseri, Pourandokht; Puran, Alicia; Davies, Justin; Baldock, Clive

    2007-01-01

    There is a need for stable gel materials for phantoms used to validate optical computerized tomography (CT) scanners used in conjunction with radiation-induced polymerizing gel dosimeters. Phantoms based on addition of light-absorbing dyes to gelatine to simulate gel dosimeters have been employed. However, to more accurately simulate polymerizing gels one requires phantoms that employ light-scattering colloidal suspensions added to the gel. In this paper, we present the initial results of using an optical CT scanner to evaluate a novel phantom in which radiation-exposed polymer gels are simulated by the addition of colloidal suspensions of varying turbidity. The phantom may be useful as a calibration transfer standard for polymer gel dosimeters. The tests reveal some phenomena peculiar to light-scattering gels that need to be taken into account when calibrating polymer gel dosimeters

  9. SAXS study of silica sols, gels and glasses obtained by the sol gel process

    International Nuclear Information System (INIS)

    Santos, D.I. dos; Aegerter, M.A.

    1988-01-01

    Systematic SAXS studies have been performed at the LURE Synchrotron, Orsay, using an intense beam of point like cross-section to obtain information about the sol -> humid gel -> dried gel -> silica glass transformation. The intensity curves have been analysed in term of power law in log-log plots, whose exponent is related to mass and surface fractal dimensions of the structure. It was found that almost all phases present fractal structures and for the case of basic gels, is of hierarchical nature. The aerogels are formed by a dense matrix, with a smooth surface and exhibit a very narrow auto-similarity range that gives a mass fractal dimension. (author) [pt

  10. Gel bead composition for metal adsorption

    Science.gov (United States)

    Scott, Charles D.; Woodward, Charlene A.; Byers, Charles H.

    1990-01-01

    The invention is a gel bead comprising propylene glycol alginate and bone gelatin and is capable of removing metals such as Sr and Cs from solution without adding other adsorbents. The invention could have application to the nuclear industry's waste removal activities.

  11. Gel phase in hydrated calcium dipicolinate

    Science.gov (United States)

    Rajak, Pankaj; Mishra, Ankit; Sheng, Chunyang; Tiwari, Subodh; Krishnamoorthy, Aravind; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya

    2017-11-01

    The mineralization of dipicolinic acid (DPA) molecules in bacterial spore cores with Ca2+ ions to form Ca-DPA is critical to the wet-heat resistance of spores. This resistance to "wet-heat" also depends on the physical properties of water and DPA in the hydrated Ca-DPA-rich protoplasm. Using reactive molecular dynamics simulations, we have determined the phase diagram of hydrated Ca-DPA as a function of temperature and water concentration, which shows the existence of a gel phase along with distinct solid-gel and gel-liquid phase transitions. Simulations reveal monotonically decreasing solid-gel-liquid transition temperatures with increasing hydration, which explains the experimental trend of wet-heat resistance of bacterial spores. Our observation of different phases of water also reconciles previous conflicting experimental findings on the state of water in bacterial spores. Further comparison with an unmineralized hydrated DPA system allows us to quantify the importance of Ca mineralization in decreasing diffusivity and increasing the heat resistance of the spore.

  12. Simple Cloud Chambers Using Gel Ice Packs

    Science.gov (United States)

    Kamata, Masahiro; Kubota, Miki

    2012-01-01

    Although cloud chambers are highly regarded as teaching aids for radiation education, school teachers have difficulty in using cloud chambers because they have to prepare dry ice or liquid nitrogen before the experiment. We developed a very simple and inexpensive cloud chamber that uses the contents of gel ice packs which can substitute for dry…

  13. 21 CFR 520.1452 - Moxidectin gel.

    Science.gov (United States)

    2010-04-01

    ...) Limitations. For oral use in horses and ponies 6 months of age and older. Not for use in horses and ponies... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1452 Moxidectin gel. (a...

  14. The Sol-Gel-Xerogel Transition

    Science.gov (United States)

    1993-11-01

    relative mobili- ty are supported by the ESR (Electron Spin Resonance) studies of * * * Ikoma et al. [301 demonstrating that polyamine copper(II) chelates...deactivation of the triplet state of the molecule in the case of RTP. Recent studies on the photoisomerization of azobenzene in sol-gel glass films by

  15. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS ...

    African Journals Online (AJOL)

    Four strains of eri, Samia cynthia ricini Lepidoptera: Saturniidae that can be identified morphologically and maintained at North East Institute of Science and Technology, Jorhat were characterized based on their protein profile by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and DNA by random ...

  16. Preparing size markers for gel electrophoresis.

    Science.gov (United States)

    Nilsen, Timothy W

    2013-12-01

    Here we present two simple methods for preparing radiolabeled size markers for gel electrophoresis. The first procedure describes the generation of an RNA marker ladder by the alkaline hydrolysis of (32)P 5'- or 3'-end-labeled RNA. The second procedure describes the labeling of DNA fragments produced by digestion of pBR322 with the restriction enzyme MspI.

  17. Denaturing urea polyacrylamide gel electrophoresis (Urea PAGE).

    Science.gov (United States)

    Summer, Heike; Grämer, René; Dröge, Peter

    2009-10-29

    Urea PAGE or denaturing urea polyacrylamide gel electrophoresis employs 6-8 M urea, which denatures secondary DNA or RNA structures and is used for their separation in a polyacrylamide gel matrix based on the molecular weight. Fragments between 2 to 500 bases, with length differences as small as a single nucleotide, can be separated using this method(1). The migration of the sample is dependent on the chosen acrylamide concentration. A higher percentage of polyacrylamide resolves lower molecular weight fragments. The combination of urea and temperatures of 45-55 degrees C during the gel run allows for the separation of unstructured DNA or RNA molecules. In general this method is required to analyze or purify single stranded DNA or RNA fragments, such as synthesized or labeled oligonucleotides or products from enzymatic cleavage reactions. In this video article we show how to prepare and run the denaturing urea polyacrylamide gels. Technical tips are included, in addition to the original protocol (1,2).

  18. Polyacrylamide gel polymerization with adjustable gelation rate

    Czech Academy of Sciences Publication Activity Database

    Wiesner, Ivo; Wiesnerová, Dana

    2002-01-01

    Roč. 32, - (2002), s. 740-742 ISSN 0736-6205 R&D Projects: GA AV ČR KSK5052113; GA ČR GA521/00/0075 Keywords : polyacrylamide gel Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.173, year: 2002

  19. Thermal Decomposition Characteristics of ADU Gel Spheres

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Kyung Chai; Eom, Sung Ho; Kim, Yeon Ku; Kim, Young Min; Kim, Woong Ki; Kim, Bong Ku; Lee, Young Woo; Cho, Moon Seoung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    HTGR nuclear fuel uses a modified sol.gel GSP (Gel Supported Precipitation) method, which is a wet method used in most countries. ADU(Ammonium DiUranate) gel particles fabricated in this way pass through thermal treatments and become final UO{sub 2} microspheres. The washing characteristics such as washing volume, duration, and times during AWD(ageing, washing and drying) process after the spherical ADU gel particles preparation by the GSP method was studied. The VHTR (Very High Temperature Gas Reactor) is one of the reactor concepts in the Gen IV International Collaboration. Unlike light water reactor currently in use in Korea, a HTGR actually functions as a gas cooled reactor where the high temperature heat generated from nuclear fission in a reactor is cooled by He gas, with uranium dioxide (UO{sub 2} is globally used) used as fuel for the nuclear fission. Generally, nuclear fuel used in a HTGR is fabricated into a TRISO (TRi.ISOtropic) structure that can prevent the leakage of nuclear fission products at high temperatures.

  20. Screening of mucoadhesive vaginal gel formulations

    Directory of Open Access Journals (Sweden)

    Ana Ochoa Andrade

    2014-12-01

    Full Text Available Rational design of vaginal drug delivery formulations requires special attention to vehicle properties that optimize vaginal coating and retention. The aim of the present work was to perform a screening of mucoadhesive vaginal gels formulated with carbomer or carrageenan in binary combination with a second polymer (carbomer, guar or xanthan gum. The gels were characterised using in vitroadhesion, spreadability and leakage potential studies, as well as rheological measurements (stress and frequency sweep tests and the effect of dilution with simulated vaginal fluid (SVF on spreadability. Results were analysed using analysis of variance and multiple factor analysis. The combination of polymers enhanced adhesion of both primary gelling agents, carbomer and carrageenan. From the rheological point of view all formulations presented a similar behaviour, prevalently elastic and characterised by loss tangent values well below 1. No correlation between rheological and adhesion behaviour was found. Carbomer and carrageenan gels containing the highest percentage of xanthan gum displayed good in vitro mucoadhesion and spreadability, minimal leakage potential and high resistance to dilution. The positive results obtained with carrageenan-xanthan gum-based gels can encourage the use of natural biocompatible adjuvants in the composition of vaginal products, a formulation field that is currently under the synthetic domain.

  1. Two-dimensional gel isoelectric focusing

    Czech Academy of Sciences Publication Activity Database

    Šťastná, Miroslava; Šlais, Karel

    2005-01-01

    Roč. 26, č. 18 (2005), s. 3586-3591 ISSN 0173-0835 R&D Projects: GA AV ČR IAA4031302; GA AV ČR IBS4031201 Institutional research plan: CEZ:AV0Z40310501 Keywords : gel isoelectric focusing * pI markers * proteins Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.850, year: 2005

  2. Effectiveness of Gel Repellents on Feral Pigeons

    Directory of Open Access Journals (Sweden)

    Birte Stock

    2013-12-01

    Full Text Available Millions of feral pigeons (Columba livia live in close association with the human population in our cities. They pose serious health risks to humans and lead to high economic loss due to damage caused to buildings. Consequently, house owners and city authorities are not willing to allow pigeons on their buildings. While various avian repellents are regularly introduced onto the market, scientific proof of efficacy is lacking. This study aimed at testing the effectiveness of two avian gel repellents and additionally examined their application from animal welfare standpoint. The gels used an alleged tactile or visual aversion of the birds, reinforced by additional sensory cues. We mounted experimental shelves with the installed repellents in a pigeon loft and observed the behavior of free-living feral pigeons towards the systems. Both gels showed a restricted, transient repellent effect, but failed to prove the claimed complete effectiveness. Additionally, the gels’ adhesive effect remains doubtful in view of animal welfare because gluing of plumage presents a risk to feral pigeons and also to other non-target birds. This study infers that both gels lack the promised complete efficacy, conflict with animal welfare concerns and are therefore not suitable for feral pigeon management in urban areas.

  3. Gels and microgels for nanotechnological applications.

    Science.gov (United States)

    Fernández-Barbero, Antonio; Suárez, Iván J; Sierra-Martín, B; Fernández-Nieves, A; de Las Nieves, F Javier; Marquez, Manuel; Rubio-Retama, J; López-Cabarcos, Enrique

    2009-01-01

    In recent years, "smart" materials have been the focus of considerable interest, from both fundamental and applied perspectives. Polymer gels are within this category; they respond to specific environmental stimuli by changing their size. Thus, the internal structure, the refractive index, and the mechanical properties of the polymer network change. They are considered super absorbent materials, as they can absorb solvent up to several hundred times their own weight. They respond rapidly to local environmental variations, an important fact in device miniaturization and microsensor developments. As size changes are accompanied by changes in internal dimensions, microgels have found application as carriers of therapeutic drugs and as diagnostic agents. They have also been used as microreactors, optically active materials, for template synthesis of nanoparticles or fabrication of artificial muscle. In this paper we review a set of application based on the special features associated to this systems. Basic concepts on the physical-chemistry of gel swelling is first described, followed by different applications covering drug delivery, composite materials using polymer gels to modulate optical or magnetic and electrical properties, molecular imprinting, gel-based biosensors and polymer sensors and actuators used in the field of artificial muscles.

  4. Sol-Gel Derived Hafnia Coatings

    Science.gov (United States)

    Feldman, Jay D.; Stackpoole, Mairead; Blum, Yigal; Sacks, Michael; Ellerby, Don; Johnson, Sylvia M.; Venkatapathy, Ethiras (Technical Monitor)

    2002-01-01

    Sol-gel derived hafnia coatings are being developed to provide an oxidation protection layer on ultra-high temperature ceramics for potential use in turbine engines (ultra-efficient engine technology being developed by NASA). Coatings using hafnia sol hafnia filler particles will be discussed along with sol synthesis and characterization.

  5. Formulation of Bioadhesive Carbomer Gel Incorporating Drug ...

    African Journals Online (AJOL)

    Purpose: To formulate carbomer gel to localize and target drug action in periodontal pockets. Methods: Diclofenac sodium (DS, anti-inflammatory) and metronidazole hydrochloride (MH, antibacterial) were loaded in gelatin microspheres using glutaraldehyde cross-linking. The microspheres were evaluated for drug loading, ...

  6. Sol–gel processing of carbidic glasses

    Indian Academy of Sciences (India)

    Unknown

    The endothermic peak and weight loss below. 200°C are associated with condensation reactions and evaporation of reaction products and residual water. The extent of these have been found to be lower than those for pure silica gels. The weight loss after 400°C is assigned to condensation of silanol groups and formation ...

  7. Fluorescence metrology of silica sol-gels

    Indian Academy of Sciences (India)

    We have developed a new method for measuring in-situ the growth of the nanometre-size silica particles which lead to the formation of sol-gel glasses. This technique is based on the decay of fluorescence polarisation anisotropy due to Brownian rotation of dye molecules bound to the particles. Results to date give near ...

  8. (3-Mercaptopropyl)trimethoxysilane-derived Porous Gel Monolith via Thioacetal Reaction-Assisted Sol-Gel Route

    Energy Technology Data Exchange (ETDEWEB)

    Ito, S; Nishi, M; Kurahashi, T; Matsubara, S; Shimotsuma, Y; Miura, K; Hirao, K [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Kanamori, K; Nakanishi, K, E-mail: west@collon1.kuic.kyoto-u.ac.jp [Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)

    2011-10-29

    Porous gel monolith was synthesized by reacting (3-mercaptopropyl)trimethoxysilane (MPTMS) with acetone on acidic conditions. It is known that MPTMS itself is difficult to turn into gel on acidic conditions and instead oligomers are obtained owing to the large mercaptopropyl group. In our system, the gels were obtained since acetone worked as a cross-linker via thioacetal reaction. Additionally, Au ions were selectively adsorbed on the obtained gel. When an obtained white gel was soaked in a chloroauric acid solution, the gel turned brown and was getting dark depending on the soaked time; on the other hand, the color of the solution turned from yellow to colorless.

  9. Normal modes of weak colloidal gels

    Science.gov (United States)

    Varga, Zsigmond; Swan, James W.

    2018-01-01

    The normal modes and relaxation rates of weak colloidal gels are investigated in calculations using different models of the hydrodynamic interactions between suspended particles. The relaxation spectrum is computed for freely draining, Rotne-Prager-Yamakawa, and accelerated Stokesian dynamics approximations of the hydrodynamic mobility in a normal mode analysis of a harmonic network representing several colloidal gels. We find that the density of states and spatial structure of the normal modes are fundamentally altered by long-ranged hydrodynamic coupling among the particles. Short-ranged coupling due to hydrodynamic lubrication affects only the relaxation rates of short-wavelength modes. Hydrodynamic models accounting for long-ranged coupling exhibit a microscopic relaxation rate for each normal mode, λ that scales as l-2, where l is the spatial correlation length of the normal mode. For the freely draining approximation, which neglects long-ranged coupling, the microscopic relaxation rate scales as l-γ, where γ varies between three and two with increasing particle volume fraction. A simple phenomenological model of the internal elastic response to normal mode fluctuations is developed, which shows that long-ranged hydrodynamic interactions play a central role in the viscoelasticity of the gel network. Dynamic simulations of hard spheres that gel in response to short-ranged depletion attractions are used to test the applicability of the density of states predictions. For particle concentrations up to 30% by volume, the power law decay of the relaxation modulus in simulations accounting for long-ranged hydrodynamic interactions agrees with predictions generated by the density of states of the corresponding harmonic networks as well as experimental measurements. For higher volume fractions, excluded volume interactions dominate the stress response, and the prediction from the harmonic network density of states fails. Analogous to the Zimm model in polymer

  10. Ultraviolet absorption detection of DNA in gels

    International Nuclear Information System (INIS)

    Mahon, A.R.

    1998-01-01

    A method and apparatus for the detection and quantification of large fragments of unlabelled deoxyribonucleic acid (DNA) in agarose gels is presented. The technique is based on ultra-violet (UV) absorption by nucleotides. A deuterium lamp was used to illuminate regions of an electrophoresis gel. As DNA bands passed through the illuminated region of the gel the amount of UV light transmitted was reduced due to DNA absorption. Two detection systems were investigated. In the first system, synthetic chemical vapour deposition (CVD) diamond strip detectors were used to locate regions of DNA in the gels by detecting the transmitted light. CVD diamond has a high indirect band gap of 5.45 eV and is therefore sensitive to UV photons of wavelengths < 224 nm. A number of CVD diamond samples were characterised to investigate their suitability as detectors for this application. The detectors' quantum efficiency, UV response and time response were measured. DNA bands containing as little as 20 ng were detected by the diamond. In a second system, a deuterium lamp was used to illuminate individual sample lanes of an electrophoresis gel via an array of optical fibres. During electrophoresis the regions of DNA were detected with illumination at 260 nm, using a UV-sensitive charge coupled device (CCD). As the absorption coefficient of a DNA sample is approximately proportional to its mass, the technique is inherently quantitative. This system had a detection limit of 0.25 ng compared with 2-10 ng for the most popular conventional technique, ethidium bromide (EtBr) staining. Using this detection technique, the DNA sample remains in its native state. The removal of carcinogenic dyes from the detection procedure greatly reduces associated biological hazards. (author)

  11. Sol-Gel Synthesis of Au-Nanoparticle Dispersed Bicontinuous Macroporous Siloxane Gel

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Y; Nishi, M; Shimotsuma, Y; Miura, K; Hirao, K, E-mail: west@collon1.kuic.kyoto-u.ac.jp [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan)

    2011-10-29

    We synthesized Au-nanoparticle dispersed siloxane gel with well-defined bicontinuous macroporous morphologies. We employed methyltrimethoxysilane (MTMS) as a precursor of the gel skeleton, and also employed hydrogen tetrachloroaurate(III) as both a precursor of Au nanoparticles and an acid catalyst for hydrolysis/condensation of methoxysilanes. The effect of adding (3-mercaptopropyl)trimethoxysilane (MPTMS) as a starting material on the obtained structure was also investigated. It is found that Au nanoparticles of 20-30 nm in grain size are uniformly dispersed on the gel surface in the system containing MPTMS; in contrast, Au nanoparticles assembled in the pits in the MPTMS-free system. All the heat-treated MPTMS-containing gels showed surface plasmon absorption, and the peaks shifted from 550 to 520 nm with increasing the calcination temperature.

  12. Gel polymer electrolytes based on PMMA III. PMMA gels containing cadmium

    Czech Academy of Sciences Publication Activity Database

    Vondrák, Jiří; Sedlaříková, M.; Velická, Jana; Klápště, Břetislav; Novák, V.; Reiter, Jakub

    2003-01-01

    Roč. 48, č. 8 (2003), s. 1001-1004 ISSN 0013-4686 R&D Projects: GA AV ČR IAA4032002; GA ČR GA104/02/0731; GA MŠk ME 216 Institutional research plan: CEZ:AV0Z4032918; CEZ:MSM 262200010 Keywords : gel polymer electrolytes * polymethylmethacrylate * cadmium gel electrolyte Subject RIV: CA - Inorganic Chemistry Impact factor: 1.996, year: 2003

  13. Simplified riboprobe purification using translucent straws as gel tubes.

    Science.gov (United States)

    Kol, S; Ben-Shlomo, I; Adashi, E Y; Rohan, R M

    1996-01-01

    Gel purification of radioactive riboprobes enhances the quality of the ribonuclease protection assay. A simple and effective method for riboprobe purification is described. The method uses acrylamide gels in plastic tubes to achieve electrophoretic separation of the RNA polymerase products.

  14. Accumulation of humic acid in DET/DGT gels

    Digital Repository Service at National Institute of Oceanography (India)

    Van der Veeken, P.L.R.; Chakraborty, P.; Van Leeuwen, H.P.

    in Thin film) that these natural complexing agents do enter the gel layer, and that humic acids even appear to accumulate in the gel, with enrichment factors typicallyonthe order of 10. The results have consequences for the interpretation of DGT...

  15. Study of nuclear glasses alteration gel and synthesis of some model gels

    International Nuclear Information System (INIS)

    Ricol, S.

    1995-01-01

    This work deals with the general problem of alteration of the reference nuclear glass R7T7. Attention is paid particularly to the altered layer formed at the glass surface during alteration process. In opposition to previous works, related essentially to glass dissolution kinetics based on chemical analyses of lixiviated elements, this thesis deals with alteration problems through structural studies of the reference glass and derived gel. This approach allows the determination of mechanisms for the gel formation and a better understanding of the behaviour of glasses towards lixiviation. Both approaches appeared complementary. Based on several spectroscopic techniques, this work showed the particular role of cations such as calcium, zirconium and iron. Studies of silica-based synthetic gels showed the synergic effect of formers cation and of one highly coordinated cation. The variation of the wavenumber related to Si-O-Si asymmetric stretching vibration can be correlated to O/Si ratio for ternary systems Si/Na/Zr. On the contrary, the Si losses of the materials depend on the number of non-bridging oxygen atoms. In the perspective of long-term behaviour, the alteration gel presents better characteristics than initial glass. It is therefore a highly stable material in static conditions. In the same way, synthetic gels are materials with very low solubilities (much lower than the alteration gel) and could be used as confining matrices. (authors). refs., 71 figs., 37 tabs

  16. Establishment of gel materials with different mechanical properties by 3D gel printer SWIM-ER

    Science.gov (United States)

    Ota, Takafumi; Tase, Taishi; Okada, Koji; Saito, Azusa; Takamatsu, Kyuuichiro; Kawakami, Masaru; Furukawa, Hidemitsu

    2016-04-01

    A 3D printer is a device which can directly produce objects whose shape is the same as the original 3D digital data. Hydrogels have unique properties such as high water content, low frictional properties, biocompatibility, material permeability and high transparency, which are rare in hard and dry materials. These superior characteristics of gels promise useful medical applications. We have been working on the development of a 3D gel printer, SWIM-ER (Soft and Wet Industrial - Easy Realizer), which can make models of organs and artificial blood vessels with gel material. However, 3D printing has a problem: the mechanical properties of the printed object vary depending on printing conditions, and this matter was investigated with SWIM-ER. In the past, we found that mechanical properties of 3D gel objects depend on the deposition orientation in SWIM-ER. In this study, gels were printed with different laser scanning speeds. The mechanical properties of these gels were investigated by compression tests, water content measurements and SMILS (Scanning Microscopic Light Scattering).

  17. Polymer gel dosimetry system for radiation therapy

    International Nuclear Information System (INIS)

    Maryanski, M.J.; Schulz, R.J.; Gignac, C.; Eastman, P.; Gore, J.C.

    1995-01-01

    Purpose/Objective: Recently developed treatment modalities such as stereotactic and conformal radiation therapy produce complex dose distributions which are difficult or impractical to measure with conventional dosimetry instrumentation. Three-dimensional treatment planning systems which purport to calculate these complex dose distributions should be compared to experimental results before being routinely applied to clinical problems. There is a need for a new class of tissue-equivalent dosimeters capable of providing accurate, high resolution, time-integrated and three dimensional dose distributions. The recently developed BANG polymer gel dosimetry system (MGS Research, Inc., Guilford, CT) is ideally suited for the task described above. Physico-chemical principles of the polymer gel dosimetry are presented, together with examples of its application to radiation therapy. Data analysis and display program, written for Macintosh computer, is demonstrated. Materials and Methods: Radiation-induced polymerization of acrylic monomers, which are dispersed in tissue-equivalent gelatin, has been shown to be dependent on the dose, but independent of the dose rate or photon energy. Therefore, the spatial distribution of polymer in the gel is precisely representative of the dose distribution. As the polymeric microparticles reduce the water proton NMR relaxation times in the gel, the dose distribution can be measured with high resolution and accuracy using magnetic resonance imaging. Also, as these microparticles cannot diffuse through the gelatin matrix, their distribution is permanent. An improved formulation of the BANG dosimeter consists of 3% w/v acrylic acid, 3% N,N'-methylene-bis-acrylamide, 1% sodium hydroxide, 5% gelatin, and 88% water. MR images are transferred via a local network to a Macintosh computer, and R2 maps constructed on the basis of multiple TE images, using a non-linear least squares fit based on the Levenberg-Marquardt algorithm. A dose-to-R2

  18. Prenatal Virilization Associated with Paternal Testosterone Gel Therapy

    OpenAIRE

    Patel, Anisha; Rivkees, Scott A.

    2010-01-01

    Transdermal testosterone gels are used in the treatment of hypoandrogenism of males. Virilization due to exposure to testosterone gels has been reported in children resulting in a US Food and Drug Administration (FDA) warning about secondary exposure to these products. At present, we are unaware of prenatal virilization associated with unintentional testosterone gel exposure. We report prenatal virilization in a female infant due to secondary maternal exposure to the father's testosterone gel...

  19. Development and dosimetric evaluation of radiochromic PCDA vesicle gel dosimeters

    International Nuclear Information System (INIS)

    Sun, P.; Fu, Y.C.; Hu, J.; Hao, N.; Huang, W.; Jiang, B.

    2016-01-01

    The gel dosimeter has the unique capacity in recording radiation dose distribution in three dimensions (3D), which has the specific advantages in dosimetry measurements where steep dose gradients exist, such as in intensity-modulated radiation therapy (IMRT), brachytherapy and so on. Some 3D dosimeters, such as Fricke gel dosimeters, polymer gel dosimeters, the PRESAGE plastic dosimeters and micelle gel dosimeters have appeared recently. However, there are several disadvantages of these 3D dosimeters limit their application in radiotherapy dose verification. In this study, a novel radiochromic gel dosimeter for 3D dose verification of radiotherapy was developed by dispersing nanovesicles self-assembled by 10,12-pentacosadiynoic acid (PCDA) into the tissue equivalence gel matrix. The characteristics of radiochromic PCDA vesicle gel dosimeters were evaluated. The results indicate that these radiochromic gel dosimeters have good linear dose response to X-ray irradiation in the dose range of 2–100 Gy. In addition, the radiochromic gel dosimeters breakthrough the limitations of the existing gel dosimeters such as diffusion effect, post-radiation effect, and poor forming ability. The response of the gel dosimeter does not show any dose rate dependence, energy dependence and temperature effect, and there was no obvious difference in the gel response between single and cumulative dose of fractional irradiation. Hence, the radiochromic PCDA vesicle gel dosimeters developed in this study could be generally applied to 3D dose verification in radiotherapy. - Highlights: • A novel radiochromic gel dosimeter was developed by dispersing PCDA nanovesicles into the tissue equivalence gel matrix. • This nanovesicle overcomes the dose image blurring caused by the diffusion of monomer molecules. • This nanovesicle limits the polymer chain growth, so as to reduce the post-radiation effect. • The gel matrixes possess excellent tissue equivalence and elastic strength, which

  20. Viscoelastic nature of Au nanoparticle–PDMS nanocomposite gels

    Indian Academy of Sciences (India)

    Even a very low Au content of 0.09 wt% is sufficient enough to bring in the transition from sponge state to gel state at room temperature. ... gel properties can have direct influence on the processability of Au nanoparticle–PDMS nanocomposite gels, with interesting implications in electronic, optical and microfluidic devices.

  1. Formulation and method for preparing gels comprising hydrous hafnium oxide

    Science.gov (United States)

    Collins, Jack L; Hunt, Rodney D; Montgomery, Frederick C

    2013-08-06

    Formulations useful for preparing hydrous hafnium oxide gels contain a metal salt including hafnium, an acid, an organic base, and a complexing agent. Methods for preparing gels containing hydrous hafnium oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including hafnium, an acid, an organic base, and a complexing agent.

  2. Power Law Behavior of Structural Properties of Protein Gels

    NARCIS (Netherlands)

    Verheul, Marleen; Roefs, Sebastianus P.F.M.; Mellema, J.; Kruif, Kees G.

    1998-01-01

    Whey proteins are globular, heat-sensitive proteins. The gel structure, the formation of this structure, and the rheological properties of particulate whey protein isolate (WPI) gels have been investigated. On increasing the NaCl concentration, the permeability of the WPI gels increased, indicating

  3. Outdoor weathering of sol-gel-treated wood

    Science.gov (United States)

    Mandla A Tshabalala; Ryan Libert; Nancy Ross Sutherland

    2009-01-01

    Outdoor weathering of wood specimens treated with sol-gel formulations based on methyltrimethoxysilane (MTMOS), hexadecyltrimethoxysilane (HDTMOS), and ferric-zirconia-titania (Fe-Zr-Ti) sol was evaluated. The sol-gel process allowed deposition of a thin film of hybrid inorganic-organic networks (gel) in the wood cell wall that resulted in improved outdoor weathering...

  4. Agarose Gel Size Selection for DNA Sequencing Libraries.

    Science.gov (United States)

    Mardis, Elaine; McCombie, W Richard

    2017-08-01

    Agarose gel electrophoresis may be used to purify fragmented genomic DNA after ligation of adaptors. After electrophoresis, the region of the gel containing the desired size range of DNA is excised, and the DNA is subsequently extracted from the gel and purified by passage through a spin column. © 2017 Cold Spring Harbor Laboratory Press.

  5. Formulation and method for preparing gels comprising hydrous aluminum oxide

    Science.gov (United States)

    Collins, Jack L.

    2014-06-17

    Formulations useful for preparing hydrous aluminum oxide gels contain a metal salt including aluminum, an organic base, and a complexing agent. Methods for preparing gels containing hydrous aluminum oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including aluminum, an organic base, and a complexing agent.

  6. Optical-CT scanning of polymer gels

    International Nuclear Information System (INIS)

    Oldham, M

    2004-01-01

    The application of optical-CT scanning to achieve accurate high-resolution 3D dosimetry is a subject of current interest. The purpose of this paper is to provide a brief overview of past research and achievements in optical-CT polymer gel dosimetry, and to review current issues and challenges. The origins of optical-CT imaging of light-scattering polymer gels are reviewed. Techniques to characterize and optimize optical-CT performance are presented. Particular attention is given to studies of artifacts in optical-CT imaging, an important area that has not been well studied to date. The technique of optical-CT simulation by Monte-Carlo modeling is introduced as a tool to explore such artifacts. New simulation studies are presented and compared with experimental data

  7. Gel Fabrication of Molybdenum “Beads”

    Energy Technology Data Exchange (ETDEWEB)

    Lowden, Richard Andrew [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Armstrong, Beth L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Cooley, Kevin M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division

    2016-11-01

    Spherical molybdenum particles or “beads” of various diameters are of interest as feedstock materials for the additive manufacture of targets and assemblies used in the production of 99Mo medical isotopes using accelerator technology. Small metallic beads or ball bearings are typically fabricated from wire; however, small molybdenum spheres cannot readily be produced in this manner. Sol-gel processes are often employed to produce small dense microspheres of metal oxides across a broad diameter range that in the case of molybdenum could be reduced and sintered to produce metallic spheres. These Sol-gel type processes were examined for forming molybdenum oxide beads; however, the molybdenum trioxide was chemically incompatible with commonly used gelation materials. As an alternative, an aqueous alginate process being assessed for the fabrication of oxide spheres for catalyst applications was employed to form molybdenum trioxide beads that were successfully reduced and sintered to produce small molybdenum spheres.

  8. Local mobility and topology in gels

    International Nuclear Information System (INIS)

    Higgins, J.S.; Ma, K.; Hall, R.H.; Warner, M.

    1981-04-01

    In the first section of this two part report entitled 'Separation of the motion around cross-link points from main chain motion in network samples' by Higgins, Ma and Hall, experimental evidence for topologically dependent diffusion in gels and rubbers is presented from high resolution neutron scattering experiments on deuterium labelled model trifunctional networks which show that the junction points move more slowly than the free chain centres by a factor of about two. In the second part by Warner entitled 'The dynamics of particular points on a polymer chain', the diffusional dynamics of particular points of a polymer chain is calculated in the Rouse approximation. The points considered correspond, in the case of incoherent neutron scattering, to the proton-labelled free ends of chains, crosslinks between chains in rubbers or gels, or the central monomers in branched or star polymers. Results derived are also relevant to NMR, ESR and computer simulation experiments. (U.K.)

  9. Solvent induced supramolecular anisotropy in molecular gels

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Michael A., E-mail: mroger09@uoguelph.ca [Department of Food Science, University of Guelph, Guelph, Ontario, N3C3X9 (Canada); Corradini, Maria G. [Department of Food Science, University of Massachusetts Amherst, Amherst, MA, 01003 (United States); Emge, Thomas [Department of Chemistry and Biochemistry, Rutgers University, New Brunswick, NJ, 08901 (United States)

    2017-06-15

    Herein is the first report of solvent induced anisotropy in 12-hydroxystearic acid self-assembled fibrillar networks. Increasing the chain length of polar solvent, such as nitriles and ketones, tailored the anisotropy of the fibrillar aggregates. 12HSA molecular gels, comprised of alkanes, exhibited an isotropic fibrillar network irrespective of the alkane chain length. In polar solvents, anisotropy, observed using 2D powder x-ray diffraction profiles, is correlated to a fibrillar supramolecular morphologies in long chain nitriles and ketones while sphereulitic crystals are correlated to x-ray diffraction patterns with an isotropic scatter intensity in short chain ketones and nitriles. These changes directly modify the final physical properties of the gels. - Highlights: • 12-HSA self-assembles into crystalline supramolecular morphologies depending on the solvent. • Alkanes, short chain nitriles and ketones led to 12-HSA displaying supramolecular isotropy. • In long chain nitriles and ketones, 12-HSA displays supramolecular anisotropy.

  10. Solvent induced supramolecular anisotropy in molecular gels

    International Nuclear Information System (INIS)

    Rogers, Michael A.; Corradini, Maria G.; Emge, Thomas

    2017-01-01

    Herein is the first report of solvent induced anisotropy in 12-hydroxystearic acid self-assembled fibrillar networks. Increasing the chain length of polar solvent, such as nitriles and ketones, tailored the anisotropy of the fibrillar aggregates. 12HSA molecular gels, comprised of alkanes, exhibited an isotropic fibrillar network irrespective of the alkane chain length. In polar solvents, anisotropy, observed using 2D powder x-ray diffraction profiles, is correlated to a fibrillar supramolecular morphologies in long chain nitriles and ketones while sphereulitic crystals are correlated to x-ray diffraction patterns with an isotropic scatter intensity in short chain ketones and nitriles. These changes directly modify the final physical properties of the gels. - Highlights: • 12-HSA self-assembles into crystalline supramolecular morphologies depending on the solvent. • Alkanes, short chain nitriles and ketones led to 12-HSA displaying supramolecular isotropy. • In long chain nitriles and ketones, 12-HSA displays supramolecular anisotropy.

  11. Gel Evolution in Oil Based Drilling Fluids

    OpenAIRE

    Sandvold, Ida

    2012-01-01

    Drilling fluids make up an essential part of the drilling operation. Successful drilling operations rely on adequate drilling fluid quality. With the development of new drilling techniques such as long deviated sections and drilling in ultra-deep waters, the standard of required performance of the drilling fluids continue to increase. Narrow pressure margins and low tolerance for barite sag requires accurate prediction of the gel evolution in drilling fluids. Increased knowledge of how dri...

  12. Sol-Gel Chemistry for Carbon Dots.

    Science.gov (United States)

    Malfatti, Luca; Innocenzi, Plinio

    2018-03-14

    Carbon dots are an emerging class of carbon-based nanostructures produced by low-cost raw materials which exhibit a widely-tunable photoluminescence and a high quantum yield. The potential of these nanomaterials as a substitute of semiconductor quantum dots in optoelectronics and biomedicine is very high, however they need a customized chemistry to be integrated in host-guest systems or functionalized in core-shell structures. This review is focused on recent advances of the sol-gel chemistry applied to the C-dots technology. The surface modification, the fine tailoring of the chemical composition and the embedding into a complex nanostructured material are the main targets of combining sol-gel processing with C-dots chemistry. In addition, the synergistic effect of the sol-gel precursor combined with the C-dots contribute to modify the intrinsic chemo-physical properties of the dots, empowering the emission efficiency or enabling the tuning of the photoluminescence over a wide range of the visible spectrum. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Sol-gel bonding of silicon wafers

    International Nuclear Information System (INIS)

    Barbe, C.J.; Cassidy, D.J.; Triani, G.; Latella, B.A.; Mitchell, D.R.G.; Finnie, K.S.; Bartlett, J.R.; Woolfrey, J.L.; Collins, G.A.

    2005-01-01

    Low temperature bonding of silicon wafers was achieved using sol-gel technology. The initial sol-gel chemistry of the coating solution was found to influence the mechanical properties of the resulting bonds. More precisely, the influence of parameters such as the alkoxide concentration, water-to-alkoxide molar ratio, pH, and solution aging on the final bond morphologies and interfacial fracture energy was studied. The thickness and density of the sol-gel coating were characterised using ellipsometry. The corresponding bonded specimens were investigated using attenuated total reflectance Fourier transformed infrared spectroscopy to monitor their chemical composition, infrared imaging to control bond integrity, and cross-sectional transmission electron microscopy to study their microstructure. Their interfacial fracture energy was measured using microindentation. An optimum water-to-alkoxide molar ratio of 10 and hydrolysis water at pH = 2 were found. Such conditions led to relatively dense films (> 90%), resulting in bonds with a fracture energy of 3.5 J/m 2 , significantly higher than those obtained using classical hydrophilic bonding (typically 1.5-2.5 J/m 2 ). Ageing of the coating solution was found to decrease the bond strength

  14. Gel Electrophoresis of Gold-DNA Nanoconjugates

    Directory of Open Access Journals (Sweden)

    T. Pellegrino

    2007-01-01

    Full Text Available Gold-DNA conjugates were investigated in detail by a comprehensive gel electrophoresis study based on 1200 gels. A controlled number of single-stranded DNA of different length was attached specifically via thiol-Au bonds to phosphine-stabilized colloidal gold nanoparticles. Alternatively, the surface of the gold particles was saturated with single stranded DNA of different length either specifically via thiol-Au bonds or by nonspecific adsorption. From the experimentally determined electrophoretic mobilities, estimates for the effective diameters of the gold-DNA conjugates were derived by applying two different data treatment approaches. The first method is based on making a calibration curve for the relation between effective diameters and mobilities with gold nanoparticles of known diameter. The second method is based on Ferguson analysis which uses gold nanoparticles of known diameter as reference database. Our study shows that effective diameters derived from gel electrophoresis measurements are affected with a high error bar as the determined values strongly depend on the method of evaluation, though relative changes in size upon binding of molecules can be detected with high precision. Furthermore, in this study, the specific attachment of DNA via gold-thiol bonds to Au nanoparticles is compared to nonspecific adsorption of DNA. Also, the maximum number of DNA molecules that can be bound per particle was determined.

  15. Epoxy Sol-Gel Hybrid Thermosets

    Directory of Open Access Journals (Sweden)

    Angels Serra

    2016-02-01

    Full Text Available Sol-gel methodologies are advantageous in the preparation of hybrid materials in front of the conventional addition of nanoparticles, because of the fine dispersion of the inorganic phase that can be reached in epoxy matrices. In addition, the use of organoalkoxysilanes as coupling agents allows covalent linkage between organic and inorganic phases, which is the key point in the improvement of mechanical properties. The sol-gel process involves hydrolysis and condensation reactions under mild conditions, starting from hydrolysable metal alkoxides, generally alkoxy silanes. Using the sol-gel procedure, the viscosity of the formulation is maintained, which is an important issue in coating applications, whereas the transparency of the polymer matrix is also maintained. However, only the proper combination of the chemistries and functionalities of both organic and inorganic structures leads to thermosets with the desired characteristics. The adequate preparation of hybrid epoxy thermosets enables their improvement in characteristics such as mechanical properties (modulus, hardness, scratch resistance, thermal and flame resistance, corrosion and antimicrobial protection, and even optical performance among others.

  16. Role of gel dosimeters in boron neutron capture therapy

    International Nuclear Information System (INIS)

    Khajeali, Azim; Farajollahi, Ali Reza; Khodadadi, Roghayeh; Kasesaz, Yaser; Khalili, Assef

    2015-01-01

    Gel dosimeters have acquired a unique status in radiotherapy, especially with the advent of the new techniques in which there is a need for three-dimensional dose measurement with high spatial resolution. One of the techniques in which the use of gel dosimeters has drawn the attention of the researchers is the boron neutron capture therapy. Exploring the history of gel dosimeters, this paper sets out to study their role in the boron neutron capture therapy dosimetric process. - Highlights: • Gel dosimeters have been investigated. • Conventional dosimetric proses of BNCT has been investigated. • Role of gel dosimeters in BNCT has been investigated

  17. Colloid molecular weight estimation by gel chromatography/acrylamide gel electrophoresis

    International Nuclear Information System (INIS)

    Liberatore, F.A.; Dearborn, C.; Nigam, S.; Poon, C.; Camin, L.; Liteplo, M.

    1984-01-01

    Size or molecular weight (MW) estimation of radiolabeled collides in aqueous solutions has long been a problem. The authors have prepared several minimicroaggregated albumin colloids (mμAA) by heat denaturation of stannous-containing HSA solutions at pH 7.0, 7.5, and 8.5). The resulting colloids were labeled with Tc-99m and compared with Au-198 colloid and Tc-99m-antimony sulfide colloid (Tc-99m-Sb/sub 2/S3) by gel chromatography and gel electrophoresis. Tc-99mm-mμAA aggregated at pH 7.0 and the Au-198 colloid appeared in the external void volume of a BioRad A5.0 agarose column indicating an apparent MW of > 5 x 10/sup 6/ daltons. The pH7.5 Tc-99m-mμAA, migrated within the filtration range of the column as did a small fraction of Tc-99m-Sb/sub 2/S/sub 3/, suggesting that the MW is between 6 x 10/sup 4/ - 5 x 10/sup 6/ daltons. The Tc-99m-mμAA, aggregated at pH 8.5, had an apparent MW on gel filtration similar to that of untreated albumin, MW 6.6 x 10-/sup 4/ daltons. The mobilities of the colloids, on acrylamide disc gel electrophoresis, were consistent with the results on gel chromatography. The largest colloids, Au-198 colloid and pH 7.0 Tc-99m-mμAA, barely entered the separating gel; intermediate sized colloids, a small fraction of Tc-99m-Sb/sub 2/S/sub 3/ and pH 7.5 Tc-99m-mμAA migrated farther into the separating gel; while pH 8.5 Tc-99m-mμAA had mobility approaching that of untreated albumin. Lymphoscintigraphy studies using these colloids in animals showed the predicted, particle size-related differences in migration and clearance. The authors conclude that gel chromatography and gel electrophoresis are useful methods for estimating the apparent size of the colloidal particles

  18. Modelling of the inhomogeneous interior of polymer gels

    International Nuclear Information System (INIS)

    Shew, C-Y; Iwaki, Takafumi

    2006-01-01

    A simple model has been investigated to elucidate the mean squared displacement (MSD) of probe molecules in cross-linked polymer gels. In the model, we assume that numerous cavities distribute in the inhomogeneous interior of a gel, and probe molecules are confined within these cavities. The individual probe molecules trapped in a gel are treated as Brownian particles confined to a spherical harmonic potential. The harmonic potential is chosen to model the effective potential experienced by the probe particle in the cavity of a gel. Each field strength is corresponding to the characteristic of one type of effective cavity. Since the statistical distribution of different effective cavity sizes is unknown, several distribution functions are examined. Meanwhile, the calculated averaged MSDs are compared to the experimental data by Nisato et al (2000 Phys. Rev. E 61 2879). We find that the theoretical results of the MSD are sensitive to the shape of the distribution function. For low cross-linked gels, the best fit is obtained when the interior cavities of a gel follow a bimodal distribution. Such a result may be attributed to the presence of at least two distinct classes of cavity in gels. For high cross-linked gels, the cavities in the gel can be depicted by a single-modal uniform distribution function, suggesting that the range of cavity sizes becomes smaller. These results manifest the voids inside a gel, and the shape of distribution functions may provide the insight into the inhomogeneous interior of a gel

  19. Antioxidant effect of green tea on polymer gel dosimeter

    International Nuclear Information System (INIS)

    Samuel, E J J; Sathiyaraj, P; Deena, T; Kumar, D S

    2015-01-01

    Extract from Green Tea (GTE) acts as an antioxidant in acrylamide based polymer gel dosimeter. In this work, PAGAT gel was used for investigation of antioxidant effect of GTE.PAGAT was called PAGTEG (Polyacrylamide green tea extract gel dosimeter) after adding GTE. Free radicals in water cause pre polymerization of polymer gel before irradiation. Polyphenols from GTE are highly effective to absorb the free radicals in water. THPC is used as an antioxidant in polymer gel dosimeter but here we were replaced it by GTE and investigated its effect by spectrophotometer. GTE added PAGAT samples response was lower compared to THPC added sample. To increase the sensitivity of the PAGTEG, sugar was added. This study confirmed that THPC was a good antioxidant for polymer gel dosimeter. However, GTE also can be used as an antioxidant in polymer gel if use less quantity (GTE) and add sugar as sensitivity enhancer

  20. Antioxidant effect of green tea on polymer gel dosimeter

    Science.gov (United States)

    Samuel, E. J. J.; Sathiyaraj, P.; Deena, T.; Kumar, D. S.

    2015-01-01

    Extract from Green Tea (GTE) acts as an antioxidant in acrylamide based polymer gel dosimeter. In this work, PAGAT gel was used for investigation of antioxidant effect of GTE.PAGAT was called PAGTEG (Polyacrylamide green tea extract gel dosimeter) after adding GTE. Free radicals in water cause pre polymerization of polymer gel before irradiation. Polyphenols from GTE are highly effective to absorb the free radicals in water. THPC is used as an antioxidant in polymer gel dosimeter but here we were replaced it by GTE and investigated its effect by spectrophotometer. GTE added PAGAT samples response was lower compared to THPC added sample. To increase the sensitivity of the PAGTEG, sugar was added. This study confirmed that THPC was a good antioxidant for polymer gel dosimeter. However, GTE also can be used as an antioxidant in polymer gel if use less quantity (GTE) and add sugar as sensitivity enhancer.

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

    Science.gov (United States)

    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. Different Applications of Rheological Techniques in Studies of Physical Gels

    DEFF Research Database (Denmark)

    Hvidt, Søren

    ] pointed out the importance of time scales for physical gels. According to him the characteristic property of a gel is the presence of two components and a constant elastic storage modulus on time scales of 1 s or frequencies of 1 rad/s. His definition of gels relies on their rheological properties......Physical gels are of both great scientific and practical interest. The cytoplasm of cells, which consists of a complex physical gel of protein filaments, is important for most of the cellular processes including cell division and cell motility. Nature has developed this complex system......-forming biopolymers. Physical gels are also used in the paint industry to minimize sedimentation. Delayed and controlled drug release is of importance in the pharmaceutical industry, and one way to obtain this control is to hide active components in physical gels. Two excellent reviews cover many aspects...

  3. High-strength cellulose/poly(ethylene glycol) gels.

    Science.gov (United States)

    Liang, Songmiao; Wu, Junjie; Tian, Huafeng; Zhang, Lina; Xu, Jian

    2008-01-01

    Cellulose gel membranes have been prepared by a pre-gelation method employing cellulose solutions in aqueous NaOH-thiourea obtained at low temperature. The cellulose gels were then swollen by low-molecular-weight polyethylene glycol (PEG; MWcellulose/PEG gels were studied by various techniques. The gels exhibit high mechanical performance, and the tensile strength of the gel membranes increases sharply with an increase in the molecular weight of PEG from 200 to 800 g mol(-1). Moreover, their elongation at break remains stable at 100 %. PEG800 efficiently improves the optical transmittance of the gel membranes at ambient temperature, which is about five times greater than that of a normal cellulose hydrogel membrane. A strong hydrogen-bonding interaction occurs between PEG and cellulose leading to a homogeneous structure, high mechanical strength and good transparency of the gel membranes.

  4. Agarose gel electrophoresis and polyacrylamide gel electrophoresis for visualization of simple sequence repeats.

    Science.gov (United States)

    Anderson, James; Wright, Drew; Meksem, Khalid

    2013-01-01

    In the modern age of genetic research there is a constant search for ways to improve the efficiency of plant selection. The most recent technology that can result in a highly efficient means of selection and still be done at a low cost is through plant selection directed by simple sequence repeats (SSRs or microsatellites). The molecular markers are used to select for certain desirable plant traits without relying on ambiguous phenotypic data. The best way to detect these is the use of gel electrophoresis. Gel electrophoresis is a common technique in laboratory settings which is used to separate deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) by size. Loading DNA and RNA onto gels allows for visualization of the size of fragments through the separation of DNA and RNA fragments. This is achieved through the use of the charge in the particles. As the fragments separate, they form into distinct bands at set sizes. We describe the ability to visualize SSRs on slab gels of agarose and polyacrylamide gel electrophoresis.

  5. Investigation of the Peroxovanadate Sol-Gel Process and Characterization of the Gels

    Energy Technology Data Exchange (ETDEWEB)

    Fontenot, Craig Joseph [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    In general, the peroxovanadate solution sol-gel process can be thought of as consisting of two parts: (1) the decomposition of the peroxo species and (2) cation hydrolysis leading to gelation. By controlling the synthesis conditions, both layered and amorphous compounds can be created. However, the type of water coordination observed in these gels was found to be identical no matter what the long-range order. The current work clarified many of the discrepancies found in the literature and offered much new valuable information. Highlights include the types of vanadium environments present at various stages of hydration, the role of adsorbed water, oxygen exchange from adsorbed water into the gel sites, and the ability to create metastable VMoO solid solution phases. These results could have a variety of impacts on future catalysis research.

  6. Data on DNA gel sample load, gel electrophoresis, PCR and cost analysis

    Directory of Open Access Journals (Sweden)

    Ramona Kuhn

    2018-02-01

    Full Text Available The data presented in this article provide supporting information to the related research article “Comparison of ten different DNA extraction procedures with respect to their suitability for environmental samples” (Kuhn et al., 2017 [1]. In that article, we compared the suitability of ten selected DNA extraction methods based on DNA quality, purity, quantity and applicability to universal PCR. Here we provide the data on the specific DNA gel sample load, all unreported gel images of crude DNA and PCR results, and the complete cost analysis for all tested extraction procedures and in addition two commercial DNA extraction kits for soil and water. Keywords: Cost analysis, DNA sample load, Gel electrophoresis

  7. Sol-gel synthesis of hydroxyapatite; Sintese de hidroxiapatita via sol-gel

    Energy Technology Data Exchange (ETDEWEB)

    Zupanski, M.D.; Lucena, M.P.P.; Bergmann, C.P., E-mail: michelledunin@yahoo.com.b [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil)

    2010-07-01

    Hydroxyapatite (HAp) has been established as the calcium phosphate based compound with most applications in the biological field. Among the numerous techniques for synthesis of HAp, the sol-gel processing route affords great control over purity and formed phases using low processing temperatures. In addition, the sol-gel approach offers an option for homogeneous HAp coating on metal substrates, as well as the ability to generate nanocrystalline powders. In this work, the sol-gel synthesis of HAp was investigated employing triethyl phosphate and calcium nitrate tetrahydrate as phosphorous and calcium precursors, respectively. The aging effect on phase composition and powder morphology of the final product was studied in terms of temperature and aging time. The powders were studied by using X-ray diffraction, Fourier transform infrared spectroscopy, particle size distribution by laser diffraction and scanning electron microscopy. (author)

  8. ANALISA DAYA SERAP SILIKA GEL BERBAHAN DASAR ABU SEKAM PADI

    Directory of Open Access Journals (Sweden)

    Hendriwan Fahmi

    2016-08-01

    Full Text Available Rice husk ash Silica Gel is aproduct which call be used in preventing the humidity by absorbing the water ion on the water andonthe air. This absorbing isbased onthe size, the composition and the total amount ofpolluter which contained on the Silica Gel. The purpose of making this silica gel is to seehow much thiskind of Silica Gel can absorb and compare it to the synthetic one,and also processing rise husk ashto be something useful, Ion water can be absorbed much more by using this natural silica gel if it is compared to the synthetic silica gel. This is because of its capable inabsorbing more –OHand O from water and air. Afterdoing a research with column method, silica gel was beingput in 50 ml water. Fromthis research, natural silica can absorb much more water (0.0010 gr/ml, 0.285 % water level ofweigh in comparing with synthetic one (0.008gr/ml with 0.248 %water level ofweight andsintering (0,007 gr/ml 0.253%water level and non-sintering silica gel contains 39.22 % weight of silica, 30.93 %weight of sintering silica gel, and 33.40 % of the synthetic. More silica and water level, means more total amount of absorbing. This silica gel application is considered with capability ofabsorbing andthe level of the water.

  9. Photo-induced locomotion of chemo-responsive polymer gels

    Science.gov (United States)

    Dayal, Pratyush; Kuksenok, Olga; Balazs, Anna C.

    2009-03-01

    The need to translate chemical energy into a mechanical response, a characteristic of many biological processes, has motivated the study of stimuli-responsive polymer gels. Recently, it has been shown experimentally that by coupling the mechanical properties of the gel with the Belousov-Zhabotinsky (BZ) reaction it is possible to induce self-sustained oscillations in the gel. One of the means for controlling these chemical oscillations is using light as an external stimulus. To study the effect of light on the mechanical behavior of the gel, we use our recently developed a 3D gel lattice spring model (gLSM) which couples the BZ reaction kinetics to the gel dynamics. In this model, the polymer-solvent interactions were taken into account by adding a coupling term to the Flory-Huggins free energy. By virtue of this coupling term, the swelling---de-swelling behavior of the gel was captured in 3D. In order to include the effect of the polymer on the reaction kinetics, the Oregonator model for the photo-sensitive BZ reaction was also modified. Using gLSM model, we probed the effect of non-uniform light irradiation on the gel dynamics. We were able to manipulate the direction and velocity of locomotion of the gel using light as a control parameter. This ability to control the movement of the gel can be utilized in a variety of applications, ranging from bio-actuators to controlled drug release systems.

  10. RNA purification by preparative polyacrylamide gel electrophoresis.

    Science.gov (United States)

    Petrov, Alexey; Wu, Tinghe; Puglisi, Elisabetta Viani; Puglisi, Joseph D

    2013-01-01

    Preparative polyacrylamide gel electrophoresis (PAGE) is a powerful tool for purifying RNA samples. Denaturing PAGE allows separation of nucleic acids that differ by a single nucleotide in length. It is commonly used to separate and purify RNA species after in vitro transcription, to purify naturally occurring RNA variants such as tRNAs, to remove degradation products, and to purify labeled RNA species. To preserve RNA integrity following purification, RNA is usually visualized by UV shadowing or stained with ethidium bromide or SYBR green dyes. © 2013 Elsevier Inc. All rights reserved.

  11. Industrial applications of sol-gel technology

    International Nuclear Information System (INIS)

    Tuloch, S.M.; Tulloch, G.E.

    1995-01-01

    The purpose of this paper has been to provide a broad, rather than comprehensive view. We have presented a range of applications and only a selection of involved companies and researchers and have relied to a large extent on published information. Nevertheless, we are sure that our view of the importance of Sol-gel technology as an emerging technology, with enormous impact across a wide range of manufacturing, is demonstrated. Applications which are either in production or have been foreshadowed include four broad categories: coatings, fibres, powders and monoliths

  12. Cumulative irritation potential of metronidazole gel compared to azelaic acid gel after repeated applications to healthy skin.

    Science.gov (United States)

    Ziel, Kristin; Yelverton, Christopher B; Balkrishnan, Rajesh; Feldman, Steven R

    2005-01-01

    Metronidazole 0.75% gel and azelaic acid 15% gel are commonly used to treat rosacea. Irritation is a common side effect. To assess the cumulative irritation potential of metronidazole 0.75% gel and azelaic acid 15% gel. Metronidazole 0.75% gel, azelaic acid 15% gel, and a white petrolatum negative control were applied under occlusive conditions to the upper back of a total of 33 healthy subjects. There were twelve 24-hour applications (4 times a week) and three 72-hour applications on weekends during a 3-week period. Skin reactions (erythema score +/- other local reaction) were assessed within 15 to 30 minutes of removal of the products. The mean cumulative irritancy index of metronidazole 0.75% gel was significantly lower than that of azelaic acid 15% gel and not significantly higher than the negative control product. There was increasing cumulative irritancy with azelaic acid; no cumulative irritancy was seen for either metronidazole or white petrolatum. Metronidazole 0.75% gel is less irritating in sustained use than azelaic acid 15% gel.

  13. Investigating potential physicochemical errors in polymer gel dosimeters

    International Nuclear Information System (INIS)

    Sedaghat, Mahbod; Lepage, Martin; Bujold, Rachel

    2011-01-01

    Measurement errors in polymer gel dosimetry can originate either during irradiation or scanning. One concern related to the exothermic nature of polymerization reaction was that the heat released in polymer gel dosimeters during irradiation modifies their dose response. In this paper, the effect of heat released from the exothermal polymerization reaction on the dose response of a number of dosimeters was studied. In addition, we investigated whether heat-generated geometric distortion existed in newly proposed gel dosimeters that contain highly thermoresponsive polymers. Our results suggest that despite a significant internal temperature increase in some gel compositions, their dose responses are not affected when oxygen is well expelled mechanically from the gel mixture. We also report on significant pre-irradiation instability in some recently developed polymer gel dosimeters but that geometric distortions were not observed. Data obtained by a set of small calibration vials are compared to those obtained from larger phantoms, and potential physicochemical causes of deviations between them are identified.

  14. Detection of Aspartic Proteinase Activities Using Gel Zymography.

    Science.gov (United States)

    Perera, Handunge Kumudu Irani

    2017-01-01

    Gel zymography is a two-stage process where the proteins from the test sample are first separated by electrophoresis followed by the detection of the activity of hydrolytic enzymes. Many zymography procedures use sodium dodecyl sulfate (SDS) polyacrylamide gels copolymerized with an appropriate substrate. The procedure described here uses native polyacrylamide gel electrophoresis (PAGE) in the absence of both SDS and substrate. In order to visualize aspartic proteinase activity, the gel is impregnated in bovine hemoglobin at pH 3.0 for 15 min after the electrophoresis procedure. Subsequently, the gel is incubated in a humid container in the absence of hemoglobin for 1 h at 37 °C. At the end, the gel is stained with amido black and destained. Clear areas against a dark background corresponding to aspartic proteinase activities can be detected.

  15. Explorative data analysis of two-dimensional electrophoresis gels

    DEFF Research Database (Denmark)

    Schultz, J.; Gottlieb, D.M.; Petersen, Marianne Kjerstine

    2004-01-01

    Methods for classification of two-dimensional (2-DE) electrophoresis gels based on multivariate data analysis are demonstrated. Two-dimensional gels of ten wheat varieties are analyzed and it is demonstrated how to classify the wheat varieties in two qualities and a method for initial screening...... of gels is presented. First, an approach is demonstrated in which no prior knowledge of the separated proteins is used. Alignment of the gels followed by a simple transformation of data makes it possible to analyze the gels in an automated explorative manner by principal component analysis, to determine...... if the gels should be further analyzed. A more detailed approach is done by analyzing spot volume lists by principal components analysis and partial least square regression. The use of spot volume data offers a mean to investigate the spot pattern and link the classified protein patterns to distinct spots...

  16. Non-stationary heat transfer in gels applied to biotehnology

    Directory of Open Access Journals (Sweden)

    Pokusaev Boris

    2017-01-01

    Full Text Available Unsteady heat transfer in agarose gels of various concentrations was studied in order to make a breakthrough in the technology of 3-D additive bioprinting. Data on the kinetics of the phase transformation was obtained using spectroscopy as a function of temperature during the formation of agarose hydrogel. The dynamics of aging was investigated for gels of different densities. The time dependence of the structural changes was obtained. Particular attention was paid to the changes in the structure of the gel due to the processes of evaporation of the liquid during the gel formation and during long-term storage. Experiments were performed to determine the dynamics of the temperature fields simultaneously with heat flux measurements during the formation of agarose gels from different initial concentrations. A technique based on experimental data for the computations of the thermophysical coefficients of agarose gels was developed.

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

    Science.gov (United States)

    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.

  18. Supramolecular gel electrophoresis of large DNA fragments.

    Science.gov (United States)

    Tazawa, Shohei; Kobayashi, Kazuhiro; Oyoshi, Takanori; Yamanaka, Masamichi

    2017-10-01

    Pulsed-field gel electrophoresis is a frequent technique used to separate exceptionally large DNA fragments. In a typical continuous field electrophoresis, it is challenging to separate DNA fragments larger than 20 kbp because they migrate at a comparable rate. To overcome this challenge, it is necessary to develop a novel matrix for the electrophoresis. Here, we describe the electrophoresis of large DNA fragments up to 166 kbp using a supramolecular gel matrix and a typical continuous field electrophoresis system. C 3 -symmetric tris-urea self-assembled into a supramolecular hydrogel in tris-boric acid-EDTA buffer, a typical buffer for DNA electrophoresis, and the supramolecular hydrogel was used as a matrix for electrophoresis to separate large DNA fragments. Three types of DNA marker, the λ-Hind III digest (2 to 23 kbp), Lambda DNA-Mono Cut Mix (10 to 49 kbp), and Marker 7 GT (10 to 165 kbp), were analyzed in this study. Large DNA fragments of greater than 100 kbp showed distinct mobility using a typical continuous field electrophoresis system. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Sol-gel precursors and products thereof

    Science.gov (United States)

    Warren, Scott C.; DiSalvo, Jr., Francis J.; Weisner, Ulrich B.

    2017-02-14

    The present invention provides a generalizable single-source sol-gel precursor capable of introducing a wide range of functionalities to metal oxides such as silica. The sol-gel precursor facilitates a one-molecule, one-step approach to the synthesis of metal-silica hybrids with combinations of biological, catalytic, magnetic, and optical functionalities. The single-source precursor also provides a flexible route for simultaneously incorporating functional species of many different types. The ligands employed for functionalizing the metal oxides are derived from a library of amino acids, hydroxy acids, or peptides and a silicon alkoxide, allowing many biological functionalities to be built into silica hybrids. The ligands can coordinate with a wide range of metals via a carboxylic acid, thereby allowing direct incorporation of inorganic functionalities from across the periodic table. Using the single-source precursor a wide range of functionalized nanostructures such as monolith structures, mesostructures, multiple metal gradient mesostructures and Stober-type nanoparticles can be synthesized. ##STR00001##

  20. Intrathecal Delivery of Ketorolac Loaded In Situ Gels for Prolonged ...

    African Journals Online (AJOL)

    Further, KT-loaded gels exhibited viscosity in the range of 1.11 to 6 cps at 50 rpm and shear thinning property (rheology testing). Additionally, the gels demonstrated 84.43 to 96.98 % drug release at the end of 12 h. In particular, in situ gels prepared from 1.2 % alginate/0.4 % HPMC (G7) exhibited excellent analgesic (54.28 ...

  1. A novel quantification method for low-density gel dosimeter.

    Science.gov (United States)

    Nedaie, Hasan Ali; Pak, Farideh; Vaezzadeh, Vahid; Eqlimi, Ehsan; Takavar, Abas; Saligheh Rad, Hamid Reza; Mosleh Shirazi, Mohammad Amin; Mirheydari, Mona

    2018-01-01

    Low signal-to-noise ratio (SNR) images of lung-like (low-density [LD]) gel dosimeters, compared to unit-density (UD) gels, necessitate the use of different quantification methods. In this study, a new method is introduced based on noise correction and exponential (NCEXP) fitting. The feasibility of NCEXP method for quantifying dose absorption in LD gels is evaluated. Sensitivity, dose resolution, detectable dynamic range, and correlation of the calibration curve for both UD and LD gel dosimeters are the parameters, which we analyze to investigate the consequences of new method. Results of NCEXP method are compared to maximum likelihood estimation of rician distribution (MLE-R) and variable echo number (VAREC) quantification methods. Dose response of LD gel dosimeter shows wider detectable dynamic range as compared to UD gel. Using NCEXP method for both LD and UD dosimeter gels, a more sensitive calibration curve with a superior dose resolution is obtained. The advantage of new quantification method is more significant for LD dosimeter gel analysis, where SNR decreases as a result of higher absorbed doses (≥10 Gy). Despite the inverse effect of the VAREC method on detectable dose range of UD gel, no specific changes are observed in dynamic dose range of LD gel dosimeter with different quantification methods. The correlations obtained with different methods were approximately of the same order for UD and LD gels. NCEXP method seems to be more effective than the MLE-R and VAREC methods for quantification of LD dosimeter gel, especially where high-dose absorption and steep-dose gradients exist such as those in intensity-modulated radiation therapy and stereotactic radiosurgery.

  2. Purification of radiolabeled RNA products using denaturing gel electrophoresis

    OpenAIRE

    Adachi, Hironori; Yu, Yi-Tao

    2014-01-01

    This unit discusses a basic method for purification of radiolabeled RNAs using denaturing polyacrylamide gel electrophoresis. The method consists of a number of experimental procedures, including total RNA preparation from yeast cells, isolation of a specific RNA from total yeast RNA, RNA 3' terminal labeling using nucleotide (5’[32P]pCp) addition (via ligation), denaturing (8 M urea) polyacrylamide gel electrophoresis, and RNA extraction from the gel slice. Key points for achieving good elec...

  3. Prenatal Virilization Associated with Paternal Testosterone Gel Therapy

    OpenAIRE

    Rivkees ScottA; Patel Anisha

    2010-01-01

    Transdermal testosterone gels are used in the treatment of hypoandrogenism of males. Virilization due to exposure to testosterone gels has been reported in children resulting in a US Food and Drug Administration (FDA) warning about secondary exposure to these products. At present, we are unaware of prenatal virilization associated with unintentional testosterone gel exposure. We report prenatal virilization in a female infant due to secondary maternal exposure to the father's testosterone ge...

  4. Formulation and evaluation of antipsoriatic gel using natural excipients

    OpenAIRE

    Raghupatruni Jhansi Laxmi; R. Karthikeyan; P. Srinivasa Babu; R.V.V. Narendra Babu

    2013-01-01

    Objective: To develop topical gel formulations of Psoralen using natural excipients to minimize the side effects of synthetic drugs. Methods: The Psoralen gel formulations were prepared using different natural gums and polymers. The physicochemical compatibility between Psoralen and other excipients was confirmed by using Fourier transform infrared spectroscopy. All prepared gel formulations were evaluated for drug content uniformity, viscosity, pH, and stability. The release of psoralen f...

  5. Capillary gel electrophoresis for rapid, high resolution DNA sequencing.

    OpenAIRE

    Swerdlow, H; Gesteland, R

    1990-01-01

    Capillary gel electrophoresis has been demonstrated for the separation and detection of DNA sequencing samples. Enzymatic dideoxy nucleotide chain termination was employed, using fluorescently tagged oligonucleotide primers and laser based on-column detection (limit of detection is 6,000 molecules per peak). Capillary gel separations were shown to be three times faster, with better resolution (2.4 x), and higher separation efficiency (5.4 x) than a conventional automated slab gel DNA sequenci...

  6. Pelepasan Ibuprofen Dari Gel Karbomer 940 Kokristal Ibuprofen-Nikotinamida

    OpenAIRE

    Agustin, Rini; Sari, Novica; Zaini, Erizal

    2014-01-01

    Salah satu metode untuk meningkatkan kelarutan adalah co-kristalisasi. Ibuprofen dapat digunakan dalam aplikasi topikal untuk rheumatoid arthrisi, sehingga telah dilakukan sebuah studi tentang formulasi dan pelepasan kokristal ibuprofen-nikotinamida dari gel karbomer 940. Kokristal diperoleh dari metode penguapan pelarut dengan komposisi equimol (1:1). Gel terdiri dari dua formula dengan jumlah ibuprofen yang sama (5%). Formula pertama adalah gel kokristal ibuprofen-nicotinamida dan Formula d...

  7. Silica scintillating materials prepared by sol-gel methods

    International Nuclear Information System (INIS)

    Werst, D.W.; Sauer, M.C. Jr.; Cromack, K.R.; Lin, Y.; Tartakovsky, E.A.; Trifunac, A.D.

    1993-01-01

    Silica was investigated as a rad-hard alternative to organic polymer hosts for organic scintillators. Silica sol-gels were prepared by hydrolysis of tetramethoxysilane in alcohol solutions. organic dyes were incorporated into the gels by dissolving in methanol at the sol stage of gel formation. The silica sol-gel matrix is very rad-hard. The radiation stability of silica scintillators prepared by this method is dye-limited. Transient radioluminescence was measured following excitation with 30 ps pulses of 20 MeV electrons

  8. Inclusion type radiochromic gel dosimeter for threedimensional dose verification

    Science.gov (United States)

    Usui, Shuji; Yoshioka, Munenori; Hayashi, Shin-ichiro; Tominaga, Takahiro

    2015-01-01

    For the verification of 3D dose distributions in modern radiation therapy, a new inclusion type radiochromic gel detector has been developed. In this gel, a hydrophobic leuco dye (leucomalachite green: LMG) was dissolved in water as an inclusion complex with highly branched cyclic dextrin. The radiation induced radical oxidation property of the LMG gel with various sensitizers was investigated. As a result, the optical dose responses were enhanced by the addition of bromoacetic acid and manganese (II) chloride. Unfavorable auto-oxidation of the gel was reduced when it was stored at 4°C.

  9. Application of CMPO containing gels to metal extraction

    International Nuclear Information System (INIS)

    Dozol, J.F.; Brunette, J.P.

    1990-01-01

    Immersed in solubility-consistent organic solvents, high polymers can swell and form gels. Choosing the organic solvent among metal extracting solvents, metal extracting gels can be prepared. The advantages of the liquid-gel extraction process, in comparison with the liquid-liquid one, are to allow the extraction of metal cations from diluted aqueous solutions by using high aqueous-organic volume ratios (metal concentration in a few stages) with easy phase separations. Various CMPO (Octyl (phenyl) -N,N-diisobutylcarbamoylmethylphosphine oxide) containing gels have been prepared, and the extraction of europium (and related actinides) has been studied

  10. Aging and nonlinear rheology of thermoreversible colloidal gels

    Science.gov (United States)

    Wagner, Norman; Gordon, Melissa; Kloxin, Christopher

    Colloidal dispersions are found in a wide variety of consumer products such as paint, food and pharmaceuticals. We investigate gel formation and aging in a thermoreverible gel consisting of octadecyl-coated silica nanoparticles suspended in n-tetradecane. In this system, the octadecyl brush can undergo a phase change allowing the attractions between particles to be tuned by temperature (1,2). By probing the system with steady shear and large amplitude oscillatory shear, we have studied the effect of thermal history and shear history on gel formation and gel mechanical properties during aging. Gels were formed by approaching a common temperature from above and below to determine a reference state from which creep tests were conducted. Creep ringing was observed as expected for the viscoelastic gel. The rheological aging is interpreted in terms of the gel microstructure formed with differing thermal and shear histories to determine how processing affects structure. Recently proposed scaling laws for the rheology and structure under flow are explored within the context of gel aging (3). Through rheological and microstructural measurements, we will further the understanding of gel formation and aging in this model system which may be applied to processing conditions in an industrial setting.

  11. Photopatterned free-standing polyacrylamide gels for microfluidic protein electrophoresis.

    Science.gov (United States)

    Duncombe, Todd A; Herr, Amy E

    2013-06-07

    Designed for compatibility with slab-gel polyacrylamide gel electrophoresis (PAGE) reagents and instruments, we detail development of free-standing polyacrylamide gel (fsPAG) microstructures supporting electrophoretic performance rivalling that of microfluidic platforms. For the protein electrophoresis study described here, fsPAGE lanes are comprised of a sample reservoir and contiguous separation gel. No enclosed microfluidic channels are employed. The fsPAG devices (120 μm tall) are directly photopatterned atop of and covalently attached to planar polymer or glass surfaces. Leveraging the fast uses readily available materials and instruments - making this technique highly accessible.

  12. High Impulse Nanoparticulate-Based Gel Propellants, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposed Small Business Innovative Research (SBIR) Phase I addresses the development of advanced gel propellants and determination of their suitability for...

  13. PCR amplification on microarrays of gel immobilized oligonucleotides

    Science.gov (United States)

    Strizhkov, Boris; Tillib, Sergei; Mikhailovich, Vladimir; Mirzabekov, Andrei

    2003-11-04

    The invention relates two general methods for performing PCR amplification, combined with the detection and analysis of the PCR products on a microchip. In the first method, the amplification occurs both outside and within a plurality of gel pads on a microchip, with at least one oligonucleotide primer immobilized in a gel pad. In the second method, PCR amplification also takes place within gel pads on a microchip, but the pads are surrounded by a hydrophobic liquid such as that which separates the individual gel pads into environments which resemble micro-miniaturized test tubes.

  14. Disc electrophoresis and related techniques of polyacrylamide gel electrophoresis

    National Research Council Canada - National Science Library

    Maurer, H. R

    1971-01-01

    ..., enzymes, antingens and radioactively labelled materials, and detailed treatments of micro disc electrophoresis, preparative polyacrylamide gel electrophoresis and many other techniques for special problems...

  15. Design of the mechanical properties of the gel by the 3D gel printer "SWIM-ER"

    Science.gov (United States)

    Saito, Azusa; Ota, Takafumi; Tase, Taishi; Takamatsu, Kyuichiro; Kawakami, Masaru; Furukawa, Hidemitsu

    2017-04-01

    In this study, we evaluated the mechanical properties of printed structures with respect to the printing orientation for "SWIM-ER". The fracture surface of the 3D modeled object of the gel does not break along the stacked line, and the maximum stress at that time is the breaking strength. Moreover, the dependency in the stacking direction is weak in the 3D model of the gel. The gel printed at high speed scan showed lower elastic modulus and higher moisture content than gel printed at low speed scan. We discussed about crosslinking density calculated based on the compressive elastic modulus and moisture content, respectively. It was found that gels having different crosslinking density can be formed by the scanning speed of UV laser. In addition, we made a prototype of a gel finger model with different mechanical properties within the model.

  16. Influence of Uranium and Polivinyl Alcohol Concentration in the Feed of Sol Gel Process on the Gel Spherical Product

    International Nuclear Information System (INIS)

    Indra Suryawan; Endang Susiantini

    2007-01-01

    The gel particles have been made at various uranium and polyvinyl alcohol concentration in the sol gel process. The variables of uranium concentration were 0.3; 0.5; 0.7; 0.9; 1.1; 1.3; 1.5; 1.7; 1.9 and 2.1 M The variables of polyvinyl alcohol concentration were 0.3; 0.6; 0.9; 1.2; 1.5; 1.8; 2.1 and 2.4 M After drying the sol gel process products were heated at 300, 500 and 750°C during 4 hours. The gel particles were characterized using an optic microscope to know the shape and condition morphology of gel. From experimental result using uranium concentration of 0.3 until 2.1 M and polyvinyl alcohol of 1.8 until 2.4 M spherical and gel was formed elastic, after heating at 750°C it was unbreakable. At the concentration of polyvinyl alcohol from 0.3 to 0.5 M, the gel product was soft and broken after being dried. At the concentration of polyvinyl alcohol from 0.6 to 0.8 M, the dried gel product was not perfect. At the concentration of polyvinyl alcohol from 0.9 to 1.7 M, the gel product of gelation process was spherical and it was broken after being heated up to 300°C. (author)

  17. Gel-eletroforese no diagnóstico da varíola Gel-electrophoresis in the smallpox diagnosis

    Directory of Open Access Journals (Sweden)

    Julio A. Mesquita

    1972-01-01

    Full Text Available O emprego de gel-eletroforese no diagnóstico da varíola, demonstrou ser ao menos trinta vezes (30X mais sensível que o teste de agar-gel, nas condições descritas (tabela I. Doze (12 espécimes, cujos testes convencionais de inoculação em ovos embrionados e de agar-gel resultaram positivos, foram testados em suas diluições originais congeladas por mais de um ano, sendo seis deles revelados por gel-eletroforese enquanto nenhum o foi por agar-gel (tabela II. Trinta e três (33 amostras isoladas no laboratório, foram testadas com material colhido de membrana cório-alantóica da primeira inoculação para o diagnóstico, conservado em glicerina 50%, resultando 15 positivas em gel-eletroforese e apenas 3 em agar-gel (tabela II. Os últimos 60 espécimes recebidos para diagnóstico, através a Campanha de Erradicação da Varíola, também resultaram negativos em gel-eletroforese, que não mostrou falsos-positivos nas condições descritas.The test of gel-electrophoresis applied to the pox virus group showed to be at least thirth times (30X more sensitive than agar-gel test on the described conditions (Table I. Twelve specimens, which were positives form Smallpox in the conventional tests of egg inoculation and agar-gel difusion test, have been screened in their original dilutions frozen for more than 1 year and six of them were still detectable by gel-eletrophoresis, while by agar-gel test any of them was positive (Table II. Thirty three Smallpox isolates have been tested with material from first egg inoculation (chorioallantoic membranes which have been stored in glycerin 50%, at - 15ºC. Fifteen of them were still positive by gel-electrophoresis and only 3 by agar-gel (Table II. The last 60 specimens received for diagnosis from Smallpox Erradication Campaign (CEV, were negatives by both tests. The gel-electrophoresis, did not show false-positives on described conditions.

  18. Radiological properties of MAGIC normoxic polymer gel dosimetry

    Science.gov (United States)

    Aljamal, M.; Zakaria, A.; Shamsuddin, S.

    2013-04-01

    For a polymer gel dosimeter to be of use in radiation dosimetry, it should display water-equivalent radiological properties. In this study, the radiological properties of the MAGIC (Methacrylic and Ascorbic acid in Gelatin Initiated by Copper) normoxic polymer gels were investigated. The mass density (ρ) was determined based on Archimedes' principle. The weight fraction of elemental composition and the effective atomic number (Zeff) were calculated. The electron density was also measured with 90° scattering angle at room temperature. The linear attenuation coefficient (μ) of unirradiated gel, irradiated gel, and water were determined using Am-241 based on narrow beam geometry. Monte Carlo simulation was used to calculate the depth doses response of MAGIC gel and water for 6MV photon beam. The weight fractions of elements composition of MAGIC gel were close to that for water. The mass density was found to be 1027 ± 2 kg m-3, which is also very close to mass density of muscle tissue (1030 kg m-3) and 2.7% higher than that of water. The electron density (ρe) and atomic number (Zeff) were found to be 3.43 × 1029 e m-3 and 7.105, respectively. The electron density measured was 2.6% greater than that for water. The atomic number was very close to that for water. The prepared MAGIC gel was found to be water equivalent based on the study of element composition, mass density, electron density and atomic number. The linear attenuation coefficient of unirradiated gel was very close to that of water. The μ of irradiated gel was found to be linear with dose 2-40 Gy. The depth dose response for MAGIC gel from a 6 MV photon beam had a percentage dose difference to water of less than 1%. Therefore it satisfies the criteria to be a good polymer gel dosimeter for radiotherapy.

  19. Sorption of neptunium(V) on silicate gels

    International Nuclear Information System (INIS)

    Del Nero, M.; Bontems, G.; Advocat, T.; Jollivet, P.

    1999-01-01

    Aqueous corrosion of nuclear waste glasses induces the formation of a gel layer enriched in hydrolyzable elements. To assess the role of such layers on the migration of Np(V) from repositories to environment, and determine the retention mechanisms, experiments have been undertaken on synthetic pure silica and on ferrisilicate gels as model solids. No detailed and systematic studies on silicate gels as scavengers for Np(V) appear to have been devoted to the influence of solution parameters and gel composition on the sorption of Np(V) on silicate gels. In this work, the fractional uptake of Np(V) on a synthetic pure silica gel and on synthetic ferrisilicate gels of controlled Si/Fe proportions (3 and 10) was measured at different ionic strengths (0.5 to 0.01 M) and Np(V) concentration levels ≅10 -10 M and 10 -6 M with pH as the main variable (3 to 10). The pH dependence of Np(V) sorption on the alternation gel was also investigated for different initial concentrations of Np(V) in the aqueous phase ≅10 -10 M, 10 -6 M and 10 -5 M. Batch experiments were carried out at 298 K under CO 2 -free conditions to avoid the formation of Np(V) carbonate complexes in the solution. As a part of this work, the charge characteristics of the gel surfaces were determined either by studying the retention of the electrolyte ions as counterions to the surface charges, as a function of pH and ionic strength of the solution contacted with gels, or by performing acid/base titrations of the alteration gel suspensions. (J.P.N.)

  20. The Gelså River Restoration Revisited

    DEFF Research Database (Denmark)

    Friberg, Nikolai; Baattrup-Pedersen, Annette; Kristensen, Esben

    2014-01-01

    The study was undertaken on the River Gelså, Denmark, where a 1.8 km meandering course was estab-lished in 1989 to replace a channelized river reach. This restoration project was the first of its kind inDenmark and has the longest time-series of post-intervention data of any restoration project...... to saturationin 1997 and that only limited immigration of new species occurred in the intervening period until 2008.The lack of long term benefits could be attributed to the simultaneous cessation of weed cutting (whichhad almost as big a positive impact as restoration), other types of stress on the river...... conductedworld-wide. Additionally, a 0.5 km upstream (control) reach that remained channelized has been sampledsince 1989. In this paper, we examined macroinvertebrate assemblages in distinct habitats in 2008, 19years after the restoration, and community persistence between two years, 1997 and 2008...

  1. Bucky gel actuator displacement: experiment and model

    International Nuclear Information System (INIS)

    Ghamsari, A K; Zegeye, E; Woldesenbet, E; Jin, Y

    2013-01-01

    Bucky gel actuator (BGA) is a dry electroactive nanocomposite which is driven with a few volts. BGA’s remarkable features make this tri-layered actuator a potential candidate for morphing applications. However, most of these applications would require a better understanding of the effective parameters that influence the BGA displacement. In this study, various sets of experiments were designed to investigate the effect of several parameters on the maximum lateral displacement of BGA. Two input parameters, voltage and frequency, and three material/design parameters, carbon nanotube type, thickness, and weight fraction of constituents were selected. A new thickness ratio term was also introduced to study the role of individual layers on BGA displacement. A model was established to predict BGA maximum displacement based on the effect of these parameters. This model showed good agreement with reported results from the literature. In addition, an important factor in the design of BGA-based devices, lifetime, was investigated. (paper)

  2. Novel inorganic tin phosphate gel: multifunctional material.

    Science.gov (United States)

    Huang, Wenyan; Komarneni, Sridhar; Noh, Young Dong; Ma, Jianfeng; Chen, Kunfeng; Xue, Dongfeng; Xue, Xiaoqiang; Jiang, Bibiao

    2018-03-08

    Here, we report a remarkable 15 Å nanolayered tin phosphate, Sn(HPO 4 ) 2 ·3H 2 O (SnP-H + or SnP), and its clay-like gel, which are multifunctional and are prepared using earth-abundant Sn and P chemicals by a facile, environmentally benign and potentially cost-effective process. This new energy material is discovered here as the best proton conductor among all the known layered phosphates with a very high proton conductivity of over 1 × 10 -2 S cm -1 at 100 °C for potential use in PEM fuel cells. But it is also a very good capacitor material with fast Li-storage kinetics (charging time of 13 s).

  3. Phyllosilicates and Amorphous Gel in the Nakhlites

    Science.gov (United States)

    Hicks, L. J.; Bridges, J. C.; Gurman, S. J.

    2013-09-01

    Previous studies of the nakhlite martian meteorites have revealed hydrothermal minerals present within the fractures of the olivine minerals and the mesostasis. The olivine fractures of the Lafayette nakhlite reveal variations with initial deposits of siderite on the fracture walls, followed by crystalline phyllosilicates (smectite), and finishing with a rapidly cooled amorphous silicate gel within the central regions of the fractures. The mesostasis fractures of Lafayette also contain a crystalline phyllosilicate (serpentine). The amorphous gel is the most abundant secondary phase within the fractures of the other nakhlites [1, 2]. By studying nine nakhlite samples, including Lafayette, Governador Valadares, Nakhla, Y-000593, Y-000749, Miller-Range 03346, NWA 817, NWA 998, and NWA 5790, our aim is to constrain the identity of the phyllosilicate secondary phase minerals found throughout the nakhlite martian meteorites. This is achieved using methods including Electron Probe Micro-analysis (EPMA); X-ray Absorption Near-Edge Structure (Fe-K XANES) spectroscopy measured using Beamline I-18 at the Diamond Light Source synchrotron; and the use of Transmission Electron Microscopy (TEM) at the University of Leicester for High-Resolution (HR) imaging and Selected Area Electron Diffraction (SAED). BF studying nine nakhlite samples, including Lafayette, Governador Valadares, Nakhla, Y-000593, Y-000749, Miller-Range 03346, NWA 817, NWA 998, and NWA 5790, our aim is to constrain the identity of the phyllosilicate secondary phase minerals found throughout the nakhlite martian meteorites. This is achieved using methods including Electron Probe Micro-analysis (EPMA); X-ray Absorption Near-Edge Structure (Fe-K XANES) spectroscopy measured using Beamline I-18 at the Diamond Light Source synchrotron; and the use of Transmission Electron Microscopy (TEM) at the University of Leicester for High-Resolution (HR) imaging and Selected Area Electron Diffraction (SAED).

  4. Clotrimazole nanoparticle gel for mucosal administration

    Energy Technology Data Exchange (ETDEWEB)

    Esposito, Elisabetta, E-mail: ese@unife.it [Department of Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara (Italy); Ravani, Laura [Department of Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara (Italy); Contado, Catia [Department of Chemistry, University of Ferrara, Ferrara (Italy); Costenaro, Andrea [Department of Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara (Italy); Drechsler, Markus [Macromolecular Chemistry II, University of Bayreuth (Germany); Rossi, Damiano [Department of Biology and Evolution, LT Terra and Acqua Tech UR7, University of Ferrara, Ferrara (Italy); Menegatti, Enea [Department of Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara (Italy); Grandini, Alessandro [Department of Biology and Evolution, LT Terra and Acqua Tech UR7, University of Ferrara, Ferrara (Italy); Cortesi, Rita [Department of Pharmaceutical Sciences, University of Ferrara, I-44121 Ferrara (Italy)

    2013-01-01

    In this study a formulation suitable to be applied on oral and/or vaginal mucosa has been developed for the treatment of fungal infections. The aim of the research is a comparison between clotrimazole (CLO) containing semisolid formulations based on monoolein aqueous dispersion (MAD) or nanostructured lipid carrier (NLC). MAD and NLC have been characterized in terms of morphology and dimensional distribution by cryogenic Transmission Electron Microscopy (cryo-TEM) and Photon Correlation Spectroscopy (PCS). CLO was encapsulated with high entrapment efficiency both in MAD and in NLC, according to Sedimentation Field Flow Fractionation (SdFFF) combined with HPLC. CLO recovery in MAD and NLC has been investigated by time. In order to obtain formulations with suitable viscosity for mucosal application, MAD was diluted with a carbomer gel, while NLC was directly viscosized by the addition of poloxamer 407 in the dispersion. The rheological properties of MAD and NLC after viscosizing have been investigated. Franz cell has been employed to study CLO diffusion from the different vehicles, evidencing diffusion rates from MAD and NLC superimposable to that obtained using Canesten{sup Registered-Sign }. An anticandidal activity study demonstrated that both CLO-MAD and CLO-NLC were more active against Candida albicans with respect to the pure drug. Highlights: Black-Right-Pointing-Pointer Comparison between monoolein aqueous dispersion (MAD) and nanostructured lipid carrier (NLC). Black-Right-Pointing-Pointer Clotrimazole (CLO) encapsulated with high entrapment efficiency both in MAD and in NLC. Black-Right-Pointing-Pointer The solid matrix of NLC controls CLO degradation better than MAD. Black-Right-Pointing-Pointer CLO containing MAD and NLC exhibits a higher anticandidal activity than the free drug. Black-Right-Pointing-Pointer Simple production of CLO-NLC based poloxamer gel, suitable for industry scaling up.

  5. Modelling of erosion of bentonite gel by gel/sol flow

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, Luis; Neretnieks, Ivars; Longcheng Liu (Chemical Engineering and Technology, School of Chemical Science and Engineering, Royal Institute of Technology, Stockholm (Sweden))

    2010-11-15

    Bentonite intrusion into a fracture intersecting the canister deposition hole is modelled. The model describes the expansion of the bentonite within the fracture. It accounts for the repulsive electrostatic double-layer forces, the attractive van der Waals forces and friction forces between the particles and the water. The model also takes into account the diffusion of the colloid particles in the smectite sol. Diffusion of a counterion, sodium, is accounted for as this strongly influences the double layer force and the viscosity of the gel/sol. The gel/sol is considered to be a fluid with a varying viscosity that is strongly dependent on the bentonite volume fraction in the gel and the sodium concentration in the water. Two different geometries were modelled; a rectangular and a cylindrical. The rectangular geometry was used to gain experience with the processes and mechanisms and how they interact since the cylindrical geometry was somewhat less stable numerically and more time consuming. In the rectangular geometry a fracture 1 metre long in the flow direction was modelled. In both geometries the fracture size was selected sufficiently large to ensure that the water velocity, near the distant border was nearly the same as the approaching water velocity and that the smectite concentration there was vanishingly small. It was found that the velocity of the fluid drops considerably where the bentonite volume fraction is larger than 1-2%. This is due to the strong increase in viscosity with increasing bentonite volume fraction. The loss of smectite by the slowly flowing fluid was found to be proportional to the square root of the seeping water velocity for the rectangular geometry. For the cylindrical geometry, the dependence is somewhat lower (exponent about 0.4) since the length of the gel/water interface decreases with increasing water flow rate. The penetration depth of the gel/water interface decreases with increasing water flow rate. For water velocity of the

  6. Explorative data analysis of two-dimensional electrophoresis gels

    DEFF Research Database (Denmark)

    Schultz, J.; Gottlieb, D.M.; Petersen, Marianne Kjerstine

    2004-01-01

    Methods for classification of two-dimensional (2-DE) electrophoresis gels based on multivariate data analysis are demonstrated. Two-dimensional gels of ten wheat varieties are analyzed and it is demonstrated how to classify the wheat varieties in two qualities and a method for initial screening...

  7. Highly Elastic and Self-Healing Composite Colloidal Gels.

    NARCIS (Netherlands)

    Diba, M.; Wang, H.; Kodger, T.E.; Parsa, S.; Leeuwenburgh, S.C.G.

    2017-01-01

    Composite colloidal gels are formed by the pH-induced electrostatic assembly of silica and gelatin nanoparticles. These injectable and moldable colloidal gels are able to withstand substantial compressive and tensile loads, and exhibit a remarkable self-healing efficiency. This study provides new,

  8. Comparative antimicrobial activities of aloe vera gel and leaf ...

    African Journals Online (AJOL)

    The comparative antimicrobial activities of the gel and leaf of Aloe vera were tested against Staphylococcus aureus, Pseudomonas aeruginosa, Trichophyton mentagraphytes, T. schoeleinii, Microsporium canis and Candida albicans. Ethanol was used for the extraction of the leaf after obtaining the gel from it. Antimicrobial ...

  9. Fast Dissolving Tablets of Aloe Vera Gel | Madan | Tropical Journal ...

    African Journals Online (AJOL)

    Purpose: The objective of this work was to prepare and evaluate fast dissolving tablets of the nutraceutical, freeze dried Aloe vera gel. Methods: Fast dissolving tablets of the nutraceutical, freeze-dried Aloe vera gel, were prepared by dry granulation method. The tablets were evaluated for crushing strength, disintegration ...

  10. Growth, characterization and dielectric property studies of gel grown ...

    Indian Academy of Sciences (India)

    Administrator

    Dielectric constant and dielectric loss have been calculated and discussed as a function of frequency at different temperatures. ... The stock solu- tion is added until the pH of the gel is set at the desired value. Test tubes were then tightly closed to prevent evaporation and contamination of the exposed surface of the gel by ...

  11. Biocatalysis with Sol-Gel Encapsulated Acid Phosphatase

    Science.gov (United States)

    Kulkarni, Suhasini; Tran, Vu; Ho, Maggie K.-M.; Phan, Chieu; Chin, Elizabeth; Wemmer, Zeke; Sommerhalter, Monika

    2010-01-01

    This experiment was performed in an upper-level undergraduate biochemistry laboratory course. Students learned how to immobilize an enzyme in a sol-gel matrix and how to perform and evaluate enzyme-activity measurements. The enzyme acid phosphatase (APase) from wheat germ was encapsulated in sol-gel beads that were prepared from the precursor…

  12. 3D Architectured Polyazomethine Gel Synthesis: Its Self Assembled ...

    Indian Academy of Sciences (India)

    23

    synthesis of polyazomethine polymer gel materials. The synthesized polymer gel is characterized by different physical techniques for testing its proper existence such as FESEM analysis, TGA analysis, DSC analysis, FTIR analysis and EDXS analysis. The morphological study has revealed that the material is having 3D ...

  13. Development and evaluation of ibuprofen transdermal gel formulations

    African Journals Online (AJOL)

    A commercial ibuprofen gel product (Ibutop®) was used as a reference. Results: The formulations containing 5 % of either menthol or glycerol as permeation enhancers gave drug release patterns comparable to that of the reference product. Propanol increased the apparent viscosity of the test gels to the same extent as that ...

  14. Radiation reaction of skin treatment with nucliderm-gel

    International Nuclear Information System (INIS)

    Pandova, V.; Marinova, Ts.; Stefanova, D.; Pantev, T.; Yankova, S.

    1988-01-01

    The process of epithelization and the anticeptic effect of nucliderm-gel applied locally have been studied in 63 oncological patients subjected to radiotherapy. In all cases under study nucliderm-gel promotes skin epithelization and has a high antiseptic effect as compared with the drugs applied hitherto

  15. Method of making ionic liquid mediated sol-gel sorbents

    Science.gov (United States)

    Malik, Abdul; Shearrow, Anne M.

    2017-01-31

    Ionic liquid (IL)-mediated sol-gel hybrid organic-inorganic materials present enormous potential for effective use in analytical microextraction. One obstacle to materializing this prospect arises from high viscosity of ILs significantly slowing down sol-gel reactions. A method was developed which provides phosphonium-based, pyridinium-based, and imidazolium-based IL-mediated advanced sol-gel organic-inorganic hybrid materials for capillary microextraction. Scanning electron microscopy results demonstrate that ILs can serve as porogenic agents in sol-gel reactions. IL-mediated sol-gel coatings prepared with silanol-terminated polymers provided up to 28 times higher extractions compared to analogous sol-gel coatings prepared without any IL in the sol solution. This study shows that IL-generated porous morphology alone is not enough to provide effective extraction media: careful choice of the organic polymer and the precursor with close sol-gel reactivity must be made to ensure effective chemical bonding of the organic polymer to the created sol-gel material to be able to provide the desired sorbent characteristics.

  16. Preparation of an efficient humidity indicating silica gel from rice ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. An efficient humidity indicating silica gel was prepared using rice husk ash as a raw material via sodium silicate extraction and acid neutralization method. Cobalt chloride was impregnated into the silica gel as a colour indicating material. A low concentration of cobalt chloride solution (0⋅0005 mol dm–3) was used ...

  17. The performance of gel technetium-99m generator

    International Nuclear Information System (INIS)

    Liu Yishu

    2004-01-01

    Technetium-99m, as one of the important radionuclides in nuclear medical science, has been widely used for diseases diagnosis in both developed and developing countries for many years. Technetium-99m can be obtained from both fission-type and gel-type Tc-99m generator. Fission-type generator was prepared by Molybdenum-99 separated from fission products of uranium-235 and gel-type was prepared by irradiating nature MoO 3 in reactor, and a series of chemical and physical processes. This paper briefly describes the manufacturing technical process of gel-type Technetium-99 generator, including the preparation of target containing nature MoO 3 , the target irradiation in reactor, gel preparation, gel filtration and drying, dried gel cracking, generator loading and activity calibration of generator. The performances of gel-type Technetium-99m generator, such as elution efficiency, elution profile, the pH, Mo breakthrough, Zirconium content, radiochemical purity, radionuclidic purity, sterility and pyrogencity of eluate, are also expatiated in detail. Comparing with fission-type Technetium-99m generator, the defects of gel-type Technetium-99m generator are enumerated and their overcoming solutions are recommended in this paper. (author)

  18. Viscoelastic nature of Au nanoparticle–PDMS nanocomposite gels

    Indian Academy of Sciences (India)

    A stable gel of Au nanoparticles in polydimethylsiloxane (PDMS) nanocomposite is prepared by employing the curing agent of PDMS elastomer as a reducing agent for the formation of Au nanoparticles by an in-situ process. The viscoelastic nature of these gels is very sensitive to the Au nanoparticle loading and the ...

  19. Slow Release Of Reagent Chemicals From Gel Matrices

    Science.gov (United States)

    Debnam, William J.; Barber, Patrick G.; Coleman, James

    1988-01-01

    Procedure developed for slow release of reagent chemicals into solutions. Simple and inexpensive and not subject to failure of equipment. Use of toothpaste-type tube or pump dispenser conceivably provides more controlled technique for storage and dispensation of gel matrix. Possible uses include controlled, slow release of reagents in chemical reactions, crystal growth, space-flight experiments, and preformed gel medications from packets.

  20. Starch gel electrophoresis of conifer seeds: a laboratory manual

    Science.gov (United States)

    M. Thompson Conkle; Paul D. Hodgskiss; Lucy B. Nunnally; Serena C. Hunter

    1982-01-01

    This manual describes fast, low-cost biochemical procedures for separating enzymes representing numerous genes of forest trees. During electrophoresis the mixture of enzymes from a megagametophyte or embryo of a germinated seed separates in a gel. Specific stains applied to gel slices locate each enzyme. These procedures expand on those developed for crops research....

  1. Self-Healing Corrosion Protective Sol-Gel Coatings

    NARCIS (Netherlands)

    Abdolah Zadeh, M.

    2016-01-01

    Inspired by the state of the art and the recent advances in the field of self-healing corrosion protective coatings, the thesis entitled “Self-healing corrosion protective sol-gel coatings” addresses novel routes to self-healing corrosion protective sol-gel coatings via extrinsic and intrinsic

  2. Recovery of DNA from agarose gel by trap method

    African Journals Online (AJOL)

    Administrator

    2011-09-05

    Sep 5, 2011 ... target band and refilling it with the same buffer. When the molecules of DNA move from agarose gel into a well, the velocity of DNA will increase in the well without interaction between gel and DNA (Stellwagen and. Stellwagen, 2009). It is possible to recover them from the. *Corresponding author. E-mail: ...

  3. Rheological properties of soybean protein isolate gels containing emulsion droplets

    NARCIS (Netherlands)

    Kim, K.H.; Renkema, J.M.S.; Vliet, van T.

    2001-01-01

    Rheological properties of soybean protein gels containing various volume fractions oil droplets have been studied at small and large deformations. Dynamic viscoelastic properties of soybean protein isolate gels were determined as a function of the volume fraction of oil droplets stabilised by the

  4. Inexpensive and Safe DNA Gel Electrophoresis Using Household Materials

    Science.gov (United States)

    Ens, S.; Olson, A. B.; Dudley, C.; Ross, N. D., III; Siddiqi, A. A.; Umoh, K. M.; Schneegurt, M. A.

    2012-01-01

    Gel electrophoresis is the single most important molecular biology technique and it is central to life sciences research, but it is often too expensive for the secondary science classroom or homeschoolers. A simple safe low-cost procedure is described here that uses household materials to construct and run DNA gel electrophoresis. Plastic…

  5. Electrical conductivity measurements on gel grown KDP crystals ...

    Indian Academy of Sciences (India)

    Unknown

    †Scott Christian College, Nagercoil 629 003, India. MS received 4 September 2000; revised 16 July 2001. Abstract. Pure and impurity added (with urea and thiourea) KDP single crystals were grown by the gel method using silica gels. Electrical conductivity measurements were carried out along both the unique axis and.

  6. 3D Architectured polyazomethine gel synthesis: its self-assembled ...

    Indian Academy of Sciences (India)

    2018-03-28

    Mar 28, 2018 ... Abstract. Azomethine is the key linkage in all Schiff base reactions. The present context has efficiently emphasized on the utilization of Schiff base strategy effectively in the synthesis of polyazomethine polymer gel materials. The synthesized polymer gel is characterized by different physical techniques for ...

  7. Electrochemical behavior of ionically crosslinked polyampholytic gel electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wanyu; Tang, Haitao; Ou, Ziwei; Wang, Hong; Yang, Yajiang [Department of Chemistry, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2007-12-31

    An ionic complex of anionic and cationic monomers was obtained by protonation of (N,N-diethylamino)ethylmethacrylate (DEA) with acrylic acid (AAc). Free radical copolymerization of the ionic complex and acrylamide (AAm), yielded the ionically crosslinked polyampholytic gel electrolytes [poly(AAc-DEA-AAm), designated as PADA] using two types of organic solvents containing a lithium salt. The PADA gel electrolyte exhibited good thermal stability shown by the DSC thermogram. The impedance analysis at temperatures ranging from -30 to 75 C indicated that the ionic conductivities of the PADA gel electrolytes were rather close to those of liquid electrolytes. The temperature dependence of the ionic conductivities was found to be in accord with the Arrhenius equation. Moreover, the ionic conductivities of PADA gel electrolytes increased with an increase of the molar ratios of cationic/anionic monomers. The ionic conductivities of PADA gels prepared in solvent mixtures of propylene carbonate, ethyl methyl ether and dioxolane (3:1:1, v/v) were higher than those of PADA gels prepared in propylene carbonate only. Significantly, the ionic conductivities of two kinds of PADA gel electrolytes were in the range of 10{sup -3} and 10{sup -4} S cm{sup -1} even at -30 C. The electrochemical windows of PADA gel electrolytes measured by cyclic voltammetry were in the range from -1 V to 4.5 V. (author)

  8. Electrochemical behavior of ionically crosslinked polyampholytic gel electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Chen Wanyu; Tang Haitao; Ou Ziwei; Wang Hong [Department of Chemistry, Huazhong University of Science and Technology, Wuhan 430074 (China); Yang Yajiang [Department of Chemistry, Huazhong University of Science and Technology, Wuhan 430074 (China)], E-mail: yjyang@mail.hust.edu.cn

    2007-12-31

    An ionic complex of anionic and cationic monomers was obtained by protonation of (N,N-diethylamino)ethylmethacrylate (DEA) with acrylic acid (AAc). Free radical copolymerization of the ionic complex and acrylamide (AAm), yielded the ionically crosslinked polyampholytic gel electrolytes [poly(AAc-DEA-AAm), designated as PADA] using two types of organic solvents containing a lithium salt. The PADA gel electrolyte exhibited good thermal stability shown by the DSC thermogram. The impedance analysis at temperatures ranging from -30 to 75 deg. C indicated that the ionic conductivities of the PADA gel electrolytes were rather close to those of liquid electrolytes. The temperature dependence of the ionic conductivities was found to be in accord with the Arrhenius equation. Moreover, the ionic conductivities of PADA gel electrolytes increased with an increase of the molar ratios of cationic/anionic monomers. The ionic conductivities of PADA gels prepared in solvent mixtures of propylene carbonate, ethyl methyl ether and dioxolane (3:1:1, v/v) were higher than those of PADA gels prepared in propylene carbonate only. Significantly, the ionic conductivities of two kinds of PADA gel electrolytes were in the range of 10{sup -3} and 10{sup -4} S cm{sup -1} even at -30 deg. C. The electrochemical windows of PADA gel electrolytes measured by cyclic voltammetry were in the range from -1 V to 4.5 V.

  9. Electrical conductivity measurements on gel grown KDP crystals ...

    Indian Academy of Sciences (India)

    2CO3 and (NH4)2SO4] KDP sin- gle crystals were grown by the gel method using silica gels. Electrical conductivity measurements were carried out along both the unique axis and perpendicular directions at various temperatures ranging from 28 ...

  10. Electrical conductivity measurements on gel grown KDP crystals ...

    Indian Academy of Sciences (India)

    Pure and impurity added (with urea and thiourea) KDP single crystals were grown by the gel method using silica gels. Electrical conductivity measurements were carried out along both the unique axis and perpendicular directions at various temperatures ranging from 30 to 140°C by the conventional two-probe method.

  11. Evaluation of Topical Gel Bases Formulated with Various Essential ...

    African Journals Online (AJOL)

    Evaluation of Topical Gel Bases Formulated with Various Essential Oils for Antibacterial Activity against Methicillin- Resistant Staphylococcus Aureus. ... Lemon grass and thyme oils were chosen for further studies, including analysis of their composition by gas chromatography–mass spectrometry (GC/MS). Gels were ...

  12. Activation energy for mullitization of gel fibres obtained from ...

    Indian Academy of Sciences (India)

    and aluminum nitrate was optimized to obtain spinnable precursor sol for synthesis of fibres. Thermogravimetry– ... (XRD) analyses were used to characterize properties of the gel and ceramic fibres. The precursor gel completely .... The polymer chains of M–O–M and M–OH–M were present while the condensation ...

  13. Comparison of the effectiveness of polymer gel dosimeters (Magic ...

    African Journals Online (AJOL)

    Purpose: To investigate and compare two polymer gel dosimeters, Magic and Pagatug, as organ dosimeters for 3D measurement of dose distribution in brachytherapy, nuclear medicine and teletherapy. Methods: Magic and Pagatug polymer gels were compared with soft tissue based on irradiation with low energy photons ...

  14. Comparison of Two Types of Gels in Improving Burn Wound

    Directory of Open Access Journals (Sweden)

    Rahimzadeh Golnar

    2014-01-01

    Full Text Available Objective: Kefir are natural probiotic compounds with anti-inflammatory properties, which were tested in experimental burn injury. Kefir gels were prepared from an extract of continuously cultured kefir in Man, Rogosa and Sharpe Broth medium for 48 and 96 h. Their extracts were used for evaluation of antibacterial effect against Pseudomonas aeruginosa in standard sample (ATCC 27853 and samples taken from patients with burns. The antibacterial effect of different kefir extract was assessment of minimum inhibitory concentration and minimum bactericidal concentration. The density of bacteria and percentage of organic acids (lactic and acetic acids were also determined. Materials and Methods: Similar burn injuries were made on dorsal skin surface of 40 rats. The rats were divided into 5 groups of 8 rats each. The base gel, silver sulfadiazine ointment, kefir 48 h gel, kefir 96 h gel were applied twice daily. Burn wound area was measured at baseline, 1 and 2 weeks. Results: Results indicated that by increasing the time of fermentation, concentration of lactic and acetic acid increased in orders of: Kefir 48 h < kefir 96 h, the end of the 2nd week the percentage of wound size were lowest in order of kefir 96 h gel < kefir grains 48 h gel < silver sulfadiazine 1% < untreated and based gel groups. Conclusion: In conclusion, the kefir gel therapy was an effective therapeutic approach to improve outcomes after severe burn when compared with conventional silver sulfadiazine treatment.

  15. DSC and conductivity studies on PVA based proton conducting gel ...

    Indian Academy of Sciences (India)

    Unknown

    An attempt has been made in the present work to prepare polyvinyl alcohol (PVA) based proton conducting gel electrolytes in ammonium thiocyanate (NH4SCN) solution and characterize ... dependence of ionic conductivity exhibits VTF behaviour. Keywords. Polymer gel electrolytes; ionic conductivity; solvent free polymer ...

  16. Evaluation of wheat by polyacrylamide gel electrophoresis | Shuaib ...

    African Journals Online (AJOL)

    ... polyacrylamide gel electrophoresis (SDS-PAGE). Electrophorogram for each variety were scored and presence or absence of each band noted and was entered in a binary data matrix. Based on the data of SDS-PAGE gels cluster analysis was performed to check the variations among varieties. The overall result shows ...

  17. Gadolinium-loaded gel scintillators for neutron and antineutrino detection

    Energy Technology Data Exchange (ETDEWEB)

    Riddle, Catherine Lynn; Akers, Douglas William; Demmer, Ricky Lynn; Paviet, Patricia Denise; Drigert, Mark William

    2016-11-29

    A gadolinium (Gd) loaded scintillation gel (Gd-ScintGel) compound allows for neutron and gamma-ray detection. The unique gel scintillator encompasses some of the best features of both liquid and solid scintillators, yet without many of the disadvantages associated therewith. Preferably, the gel scintillator is a water soluble Gd-DTPA compound and water soluble fluorophores such as: CdSe/ZnS (or ZnS) quantum dot (Q-dot) nanoparticles, coumarin derivatives 7-hydroxy-4-methylcoumarin, 7-hydroxy-4-methylcoumarin-3-acetic acid, 7-hydroxycoumarin-3-carboxylic acid, and Alexa Fluor 350 as well as a carbostyril compound, carbostyril 124 in a stable water-based gel, such as methylcellulose or polyacrylamide polymers. The Gd-loaded ScintGel allows for a homogenious distribution of the Gd-DTPA and the fluorophores, and yields clean fluorescent emission peaks. A moderator, such as deuterium or a water-based clear polymer, can be incorporated in the Gd-ScintGel. The gel scintillators can be used in compact detectors, including neutron and antineutrino detectors.

  18. Development and mechanical characterisation of self-compressed collagen gels.

    Science.gov (United States)

    Andriakopoulou, C E; Zadpoor, A A; Grant, M H; Riches, P E

    2018-03-01

    Collagen gels are considered a promising biomaterial for the manufacturing of tissue engineering scaffolds, however, their mechanical properties often need to be improved to enable them to provide enough mechanical support during the course of tissue regeneration process. In this paper, we present a simple self-compression technique for the improvement of the mechanical properties of collagen gels, identified by the fitting of bespoke biphasic finite element models. Radially-confined highly hydrated gels were allowed to self-compress for 18h, expelling fluid, and which were subsequently subjected to unconfined ramp-hold compression. Gels, initially of 0.2%, 0.3% and 0.4% (w/v) collagen and 13mm thickness, transformed to 2.9±0.2%, 3.2±0.3% and 3.6±0.1% (w/w) collagen and 0.45±0.06mm, 0.69±0.04mm and 0.99±0.07mm thickness. Young's moduli of the compressed gels did not increase with increasing collagen fibril density, whilst zero-strain hydraulic permeability significantly decreased from 51 to 21mm 4 /Ns. The work demonstrates that biphasic theory, applied to unconfined compression, is a highly appropriate paradigm to mechanically characterise concentrated collagen gels and that confined compression of highly hydrated gels should be further investigated to enhance gel mechanical performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Preparation of continuous alumina gel fibres by aqueous sol–gel ...

    Indian Academy of Sciences (India)

    lowed by being heated in a water bath at 80. ◦. C. The proper amount of water and spinning additive (PVP) were added in the AL gel, and then the precursor sol was concentrated to obtain a spinning sol in the water bath (60 .... ing point phase (e.g. SiO2, B2O3, TiO2) (Minnesota Mining and Manufacturing Company 1977).

  20. In-gel digestion for mass spectrometric characterization of RNA from fluorescently stained polyacrylamide gels.

    Science.gov (United States)

    Taoka, Masato; Ikumi, Maki; Nakayama, Hiroshi; Masaki, Shunpei; Matsuda, Ryozo; Nobe, Yuko; Yamauchi, Yoshio; Takeda, Jun; Takahashi, Nobuhiro; Isobe, Toshiaki

    2010-09-15

    Although current mass spectrometry-based proteomics technology allows for high-throughput analysis of protein components in functional ribonucleoprotein complexes, this technology has had limited application to studies of RNA itself. Here we present a protocol for RNA analysis using polyacrylamide gel electrophoresis coupled with liquid chromatography-tandem mass spectrometry. Specifically, RNAs of interest are subjected to polyacrylamide gel electrophoresis and stained with a fluorescent dye, and RNAs in gel bands are digested with nuclease and then analyzed directly liquid chromatography-mass spectrometry, resulting in highly accurate mass values and reliable information on post-transcriptional modifications. We demonstrate that the method can be applied to the identification and chemical analysis of small RNAs in mouse embryonic stem cell extracts and of small RNAs in the spliceosomal ribonucleoprotein complex pulled down from yeast cells using a tagged protein cofactor as bait. The protocol is relatively simple and allowed us to identify not only three novel methylated nucleotide residues of RNase P RNA, U6 snRNA, and 7SL RNA prepared from mouse ES cells but also various 3'-end forms of U4, U5S, and U6 snRNAs isolated from the yeast spliceosome at the femtomole level. The method is thus a convenient tool for direct analysis of RNAs in various cellular ribonucleoprotein complexes, particularly for the analysis of post-transcriptional modifications and metabolic processing of RNA.

  1. Anaphylactoid reaction after use of intracervical dinoprostone gel.

    Science.gov (United States)

    Vaidya, Madhuri; Ghike, Sunita; Jain, Sheela

    2014-03-01

    Anaphylactic-like reaction or anaphylactoid reaction resembles generalized anaphylaxis but is not caused by immunoglobulin E-mediated allergic reaction. This reaction is caused by a non-immunologic mechanism even after first exposure to antigen. Prostaglandin E2 (dinoprostone) gel is commonly used for pre-induction cervical ripening. We report a case of anaphylactiod reaction after insertion of prostaglandin E2 gel for induction of labor. Hyperstimulation with dinoprostone gel is reported in the literature. An isolated report of three cases of anaphylactiod reaction after intracervical dinoprostone gel was found during a literature search. We are reporting this case for its rarity. As a potentially life-threatening condition, every obstetrician should be aware of this rare complication of dinoprostone gel.

  2. Molecular Gels Materials with Self-Assembled Fibrillar Networks

    CERN Document Server

    Weiss, Richard G

    2006-01-01

    Molecular gels and fibrillar networks – a comprehensive guide to experiment and theory Molecular Gels: Materials with Self-Assembled Fibrillar Networks provides a comprehensive treatise on gelators, especially low molecular-mass gelators (LMOGs), and the properties of their gels. The structures and modes of formation of the self-assembled fibrillar networks (SAFINs) that immobilize the liquid components of the gels are discussed experimentally and theoretically. The spectroscopic, rheological, and structural features of the different classes of LMOGs are also presented. Many examples of the application of the principal analytical techniques for investigation of molecular gels (including SANS, SAXS, WAXS, UV-vis absorption, fluorescence and CD spectroscopies, scanning electron, transmission electron and optical microscopies, and molecular modeling) are presented didactically and in-depth, as are several of the theories of the stages of aggregation of individual LMOG molecules leading to SAFINs. Several actua...

  3. Tetracaine gel vs EMLA cream for percutaneous anaesthesia in children

    DEFF Research Database (Denmark)

    Rømsing, Janne; Henneberg, S W; Walther-Larsen, S

    1999-01-01

    We have evaluated the anaesthetic effect of tetracaine gel 1 g, applied for 45 min, compared with EMLA cream 2 g, applied for 60 min, in a randomized, double-blind study in 60 children aged 3-15 yr. Venous cannulation was performed 15 min after removal of the EMLA cream (n = 20) and tetracaine gel...... (n = 20). Cannulation was performed up to 215 min after removal of the tetracaine gel in another 20 patients. Significantly lower pain scores were recorded by the children treated with tetracaine gel compared with EMLA cream (P ... no pain compared with only 10% in the EMLA group. Only minor adverse effects were observed. We conclude that tetracaine gel provided effective, rapid, long-lasting and safe local anaesthesia, and was significantly better than EMLA cream in reducing pain during venous cannulation in children using...

  4. [Role of the i-gel in emergency airway management].

    Science.gov (United States)

    Ueshima, Hironobu; Asai, Takashi

    2014-04-01

    The i-gel is a relatively new supraglottic airway, which has been shown to be useful during general anesthesia, and it may have a potential role during cardiopulmonary resuscitation. In a manikin study, we have found that, compared with laryngeal mask airways, the i-gel was significantly easier and faster to insert, due mainly to no-necessity of cuff inflation. One possible difficulty in using the i-gel during cardiopulmonary resuscitation is that the device cannot be fixed with the Thomas Tube Holder (Laerdal Medical Japan KK, Tokyo, Japan). A specially tailored device for cardiopulmonary resuscitation, recently has become available. The pack includes the i-gel O2 (which has a side port for oxygen delivery), a suction catheter, a sachet containing lubrication jelly, and a fixation strap. We describe the role of the i-gel during emergency airway management.

  5. [Semisynthetic cellulose derivatives as the base of hydrophilic gel systems].

    Science.gov (United States)

    Bajerová, M; Gajdziok, J; Dvorácková, K; Masteiková, R; Kollár, P

    2008-04-01

    The field of drug technology widely ulilizes gel systems of high-molecular substances, which have a number of advantages, such as low toxicity, availability, unique physical properties, biocompatibility, mucoadhesivity, and others. Gel systems are used in the field of local as well as general therapy, in both shape-specific and shape-non-specific dosage forms, in medicaments of the first, second, and third generations. An important group of gels employed in pharmacy are hydrophilic gels or hydrogels, most frequently composed of hydrophilic polymers of natural, semisynthetic and synthetic origin. Though cellulose derivatives as the representatives of polymers of semisynthetic origin are used in pharmaceutical technology for a long time, their research continues and their other possible uses are being searched for. Their advantages include especially safety, easy availability, and a relatively low price. The review paper describes selected cellulose derivatives, their properties and uses in pharmaceutical technology with regard to their use in the field of production of gel systems.

  6. Ion-Gel-Gated Graphene Optical Modulator with Hysteretic Behavior.

    Science.gov (United States)

    Kim, Jin Tae; Choi, Hongkyw; Choi, Yongsuk; Cho, Jeong Ho

    2018-01-17

    We propose a graphene-based optical modulator and comprehensively investigate its photonic characteristics by electrically controlling the device with an ion-gel top-gate dielectric. The density of the electrically driven charge carriers in the ion-gel gate dielectric plays a key role in tuning the optical output power of the device. The charge density at the ion-gel-graphene interface is tuned electrically, and the chemical potential of graphene is then changed to control its light absorption strength. The optical behavior of the ion-gel gate dielectric exhibits a large hysteresis which originates from the inherent nature of the ionic gel and the graphene-ion-gel interface and a slow polarization response time of ions. The photonic device is applicable to both TE- and TM-polarized light waves, covering two entire optical communication bands, the O-band (1.26-1.36 μm) and the C-band (1.52-1.565 μm). The experimental results are in good agreement with theoretically simulated predictions. The temporal behavior of the ion-gel-graphene-integrated optical modulator reveals a long-term modulation state because of the relatively low mobility of the ions in the ion-gel solution and formation of the electric double layer in the graphene-ion-gel interface. Fast dynamic recovery is observed by applying an opposite voltage gate pulse. This study paves the way to the understanding of the operational principles and future applications of ion-gel-gated graphene optical devices in photonics.

  7. Improved gel electrophoresis matrix for hydrophobic protein separation and identification.

    Science.gov (United States)

    Tokarski, Caroline; Fillet, Marianne; Rolando, Christian

    2011-03-01

    We propose an improved acrylamide gel for the separation of hydrophobic proteins. The separation strategy is based on the incorporation of N-alkylated and N,N'-dialkylated acrylamide monomers in the gel composition in order to increase hydrophobic interactions between the gel matrix and the membrane proteins. Focusing on the most efficient monomer, N,N'-dimethylacrylamide, the potentiality of the new matrix was evaluated on membrane proteins of the human colon HCT-116 cell line. Protein analysis was performed using an adapted analytical strategy based on FT-ICR tandem mass spectrometry. As a result of this comparative study, including advanced reproducibility experiments, more hydrophobic proteins were identified in the new gel (average GRAVY: -0.085) than in the classical gel (average GRAVY: -0.411). Highly hydrophobic peptides were identified reaching a GRAVY value up to 1.450, therefore indicating their probable locations in the membrane. Focusing on predicted transmembrane domains, it can be pointed out that 27 proteins were identified in the hydrophobic gel containing up to 11 transmembrane domains; in the classical gel, only 5 proteins containing 1 transmembrane domain were successfully identified. For example, multiple ionic channels and receptors were characterized in the hydrophobic gel such as the sodium/potassium channel and the glutamate or the transferrin receptors whereas they are traditionally detected using specific enrichment techniques such as immunoprecipitation. In total, membrane proteins identified in the classical gel are well documented in the literature, while most of the membrane proteins only identified on the hydrophobic gel have rarely or never been described using a proteomic-based approach. 2010 Elsevier Inc. All rights reserved.

  8. The effects of brushing on human enamel surface roughness after NaF gel and theobromine gel exposure

    Science.gov (United States)

    Mahardhika, A.; Noerdin, A.; Eriwati, Y. K.

    2017-08-01

    This study aimed to determine the effects of brushing on human enamel surface roughness after different exposure times of 200 mg/L theobromine gel (8, 16, and 32 minutes) and 2% NaF gel (16 minutes). Twenty-four human upper premolars were used and divided into four groups. Group 1 was exposed to 2% NaF gel for 16 minutes. In contrast, groups 2, 3, and 4 were exposed to 200 mg/L theobromine gel for 8 minutes, 16 minutes, and 32 minutes, and each group was then brushed for 9 minutes and 20 seconds. After the treatment, samples were tested using a surface roughness tester (Mitutoyo SJ 301, Japan). The Wilcoxon test showed significant changes (p theobromine gel or NaF gel and after brushing for 9 minutes and 20 seconds. It can be concluded that exposure to 200 mg/L theobromine gel or 2% NaF gel can soften the enamel surface and then increase roughness after brushing.

  9. ANALISIS KEKUATAN GEL (GEL STRENGTH PRODUK PERMEN JELLY DARI GELATIN KULIT IKAN CUCUT DENGAN PENAMBAHAN KARAGINAN DAN RUMPUT LAUT

    Directory of Open Access Journals (Sweden)

    pipih - suptijah

    2014-06-01

    Full Text Available AbstrakPermen jelly merupakan permen bertekstur kenyal dengan penambahan komponen hidrokoloid,misalnya agar, gum, pektin, pati, karaginan, gelatin, dan lain-lain yang digunakan untuk modifi kasitekstur sehingga menghasilkan produk yang kenyal. Penelitian ini bertujuan menentukan kekuatan gel (gelstrength dan formulasi terbaik dari permen jelly yang berasal dari gelatin kulit ikan cucut dan karaginan.Metode analisis yang digunakan, meliputi analisis proksimat, pH, rendemen, viskositas, analisis sensori,dan kekuatan gel. Konsentrasi asam asetat terbaik dalam pembuatan gelatin adalah 0,1 N dan formulasipermen jelly terbaik terdapat pada permen jelly yang dibuat dari gelatin 1,75% dan karaginan 3,50% denganmenghasilkan kekuatan gel 169,35 N/cm2.Kata kunci: gelatin, ikan cucut, kekuatan gel (gel strength, permen jelly

  10. Agarose gel electrophoresis for the separation of DNA fragments.

    Science.gov (United States)

    Lee, Pei Yun; Costumbrado, John; Hsu, Chih-Yuan; Kim, Yong Hoon

    2012-04-20

    Agarose gel electrophoresis is the most effective way of separating DNA fragments of varying sizes ranging from 100 bp to 25 kb(1). Agarose is isolated from the seaweed genera Gelidium and Gracilaria, and consists of repeated agarobiose (L- and D-galactose) subunits(2). During gelation, agarose polymers associate non-covalently and form a network of bundles whose pore sizes determine a gel's molecular sieving properties. The use of agarose gel electrophoresis revolutionized the separation of DNA. Prior to the adoption of agarose gels, DNA was primarily separated using sucrose density gradient centrifugation, which only provided an approximation of size. To separate DNA using agarose gel electrophoresis, the DNA is loaded into pre-cast wells in the gel and a current applied. The phosphate backbone of the DNA (and RNA) molecule is negatively charged, therefore when placed in an electric field, DNA fragments will migrate to the positively charged anode. Because DNA has a uniform mass/charge ratio, DNA molecules are separated by size within an agarose gel in a pattern such that the distance traveled is inversely proportional to the log of its molecular weight(3). The leading model for DNA movement through an agarose gel is "biased reptation", whereby the leading edge moves forward and pulls the rest of the molecule along(4). The rate of migration of a DNA molecule through a gel is determined by the following: 1) size of DNA molecule; 2) agarose concentration; 3) DNA conformation(5); 4) voltage applied, 5) presence of ethidium bromide, 6) type of agarose and 7) electrophoresis buffer. After separation, the DNA molecules can be visualized under uv light after staining with an appropriate dye. By following this protocol, students should be able to: Understand the mechanism by which DNA fragments are separated within a gel matrix Understand how conformation of the DNA molecule will determine its mobility through a gel matrix Identify an agarose solution of appropriate

  11. Influence of colloidal silicon dioxide on gel strength, robustness, and adhesive properties of diclofenac gel formulation for topical application.

    Science.gov (United States)

    Lu, Zheng; Fassihi, Reza

    2015-06-01

    The objective of this study is to identify the extent of stiffness, adhesiveness, and thixotropic character of a three-dimensional gel network of a 1% diclofenac sodium topical gel formulation in the presence and absence of colloidal silicon dioxide (CSD) and assess its ease of application and adhesiveness using both objective and subjective analysis. The 1% diclofenac gel was mixed with different amounts of CSD (e.g., 0.5, 1, 2, 3, and 5% w/w) and allowed to equilibrate prior to testing. The texture analyzer in combination with a cone-cap assembly was used to objectively investigate the changes in spreadability and adhesiveness of the gel system before and after addition of CSD. Results indicate that an increase in pliability and adhesiveness at levels ≥2 to ≤5% w/w of CSD dispersed in the gel ensues. For subjective analysis, gels with (2% w/w) CSD and in the absence of CSD were uniformly applied to a 20-cm(2) (5 cm × 4 cm) surface area on the forearms of healthy volunteers and vehicle preferences by the volunteers regarding ease of application, durability on the skin, compliance, and feelings concerning its textural properties were assessed. It appears that changes in the gel formulation with the addition of CSD enhance gel viscosity and bonding to the skin. Results further show that changes in physical and rheological characteristics of gel containing 2% w/w CSD did not significantly change subject preferences for the gel preparations. These findings may help formulators to have additional options to develop more robust and cost-effective formulations.

  12. Etodolac Containing Topical Niosomal Gel: Formulation Development and Evaluation

    Directory of Open Access Journals (Sweden)

    Gyati Shilakari Asthana

    2016-01-01

    Full Text Available The present study aimed to investigate the delivery potential of Etodolac (ETD containing topical niosomal gel. Niosomal formulations were prepared by thin film hydration method at various ratios of cholesterol and Span 60 and were evaluated with respect to particle size, shape, entrapment efficiency, and in vitro characteristics. Dicetyl phosphate (DCP was also added in the niosomal formulation. Mean particle size of niosomal formulation was found to be in the range of 2 μm to 4 μm. Niosomal formulation N2 (1 : 1 ratio of cholesterol and surfactant displayed good entrapment efficiency (96.72%. TEM analyses showed that niosomal formulation was spherical in shape. Niosomal formulation (N2 displayed high percentage of drug release after 24 h (94.91 at (1 : 1 ratio of cholesterol : surfactant. Further selected niosomal formulation was used to formulate topical gel and was characterized with respect to its various parameters such as pH, viscosity, spreadability, ex vivo study, and in vivo potential permeation. Ex vivo study showed that niosomal gel possessed better skin permeation study than the plain topical gel. Further in vivo study revealed good inhibition of inflammation in case of topical niosomal gel than plain gel and niosomal formulation. The present study suggested that topical niosomal gel formulations provide sustained and prolonged delivery of drug.

  13. Etodolac Containing Topical Niosomal Gel: Formulation Development and Evaluation.

    Science.gov (United States)

    Shilakari Asthana, Gyati; Asthana, Abhay; Singh, Davinder; Sharma, Parveen Kumar

    2016-01-01

    The present study aimed to investigate the delivery potential of Etodolac (ETD) containing topical niosomal gel. Niosomal formulations were prepared by thin film hydration method at various ratios of cholesterol and Span 60 and were evaluated with respect to particle size, shape, entrapment efficiency, and in vitro characteristics. Dicetyl phosphate (DCP) was also added in the niosomal formulation. Mean particle size of niosomal formulation was found to be in the range of 2 μm to 4 μm. Niosomal formulation N2 (1 : 1) ratio of cholesterol and surfactant displayed good entrapment efficiency (96.72%). TEM analyses showed that niosomal formulation was spherical in shape. Niosomal formulation (N2) displayed high percentage of drug release after 24 h (94.91) at (1 : 1) ratio of cholesterol : surfactant. Further selected niosomal formulation was used to formulate topical gel and was characterized with respect to its various parameters such as pH, viscosity, spreadability, ex vivo study, and in vivo potential permeation. Ex vivo study showed that niosomal gel possessed better skin permeation study than the plain topical gel. Further in vivo study revealed good inhibition of inflammation in case of topical niosomal gel than plain gel and niosomal formulation. The present study suggested that topical niosomal gel formulations provide sustained and prolonged delivery of drug.

  14. Gellan gum fluid gels for topical administration of diclofenac.

    Science.gov (United States)

    Mahdi, Mohammed H; Conway, Barbara R; Mills, Thomas; Smith, Alan M

    2016-12-30

    Diclofenac topical formulations are often preferred for drug administration to patients who experience serious GIT problems. Absorption of the drug through the skin, however, can be challenging due to the natural protective feature of the stratum corneum (SC). In this article, fluid gels prepared from gellan gum were explored as a topical drug delivery vehicle. Rheological analysis of the formulations showed that it was possible to produce a topical gel with a viscosity and the mechanical strength similar to that of the commercially available Voltaren ® gel using 1% w/w of a 50:50 low acyl/high acyl (LA/HA) gellan blend. Soft-tribology was used to assess the lubrication properties of gellan fluid gels. The lubrication of the gellan gum fluid gel formulations at high rubbing speeds was similar to the lubrication of the Voltaren ® gel. The use of gellan gum dramatically increased skin permeation of diclofenac when compared with the commercially available formulation and could be controlled by changing the gellan gum concentration and/or sodium ion concentration in the formulation. This study highlights the potential use of fluid gels that can be easily tuned to have physical properties suitable for topical formulations with the added advantage of increasing drug permeation. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Antibacterial Activity of Copaiba Oil Gel on Dental Biofilm.

    Science.gov (United States)

    Simões, Cláudia A C G; Conde, Nikeila C de Oliveira; Venâncio, Gisely N; Milério, Patrícia S L L; Bandeira, Maria F C L; da Veiga Júnior, Valdir F

    2016-01-01

    Amazonian biodiversity products that have been used for years in folk medicine, have emerged as feasible and promising alternatives for the inhibition of microorganisms in dental biofilm. Copaiba oil, a phytotherapic agent widely used by the Amazonian populations, is known for its antibacterial, anti-inflammatory, anesthetic, healing and antitumor medicinal properties. The aim of this study was to evaluate the in vitro antibacterial activity of copaiba oil (Copaifera multijuga) gel against strains of Streptococcus sp present in dental biofilm. The copaiba oil was obtained and the chemical components were identified. The oil emulsions were formulated and used with the Brain Heart Infusion agar diffusion method with strains of Streptococcus mitis, Streptococcus constellatus and Streptococcus salivarius isolated from patients as well as standard strains of S. mitis (ATCC903), S. mutans (ATCC10449), S. sanguinis (ATCC15300) and S. oralis (ATCC10557). The study groups were as follows: experimental copaiba oil gel, 1% chlorhexidine gel (positive control) and base gel (negative control). The seeded plates were incubated at 37ºC for 12, 24 and 48 hours, respectively. The results obtained were analyzed by Shapiro-Wilk and Friedman Tests (p<0.05) for non parametric data and the Tukey test was used for pH values with 5% level of significance. The experimental copaiba oil gel and 1% chlorhexidine gel showed antibacterial activity against the tested microorganisms. The copaiba oil gel demonstrated antibacterial activity against all the strains of Streptococcus sp tested, suggesting that it can be used for dental biofilm control.

  16. Pickering stabilized peptide gel particles as tunable microenvironments for biocatalysis.

    Science.gov (United States)

    Scott, Gary; Roy, Sangita; Abul-Haija, Yousef M; Fleming, Scott; Bai, Shuo; Ulijn, Rein V

    2013-11-19

    We demonstrate the preparation of peptide gel microparticles that are emulsified and stabilized by SiO2 nanoparticles. The gels are composed of aromatic peptide amphiphiles 9-fluorenylmethoxycarbonyldiphenylalanine (Fmoc-FF) coassembled with Fmoc-amino acids with different functional groups (S: serine; D: aspartic acid; K: lysine; and Y: tyrosine). The gel phase provides a highly hydrated matrix, and peptide self-assembly endows the matrix with tunable chemical environments which may be exploited to support and stabilize proteins. The use of Pickering emulsion to stabilize these gel particles is advantageous through avoidance of surfactants that may denature proteins. The performance of enzyme lipase B immobilized in pickering/gel microparticles with different chemical functionalities is investigated by studying transesterification in heptane. We show that the use of Pickering particles enhances the performance of the enzyme, which is further improved in gel-phase systems, with hydrophilic environment provided by Fmoc-FF/S giving rise to the best catalytic performance. The combination of a tunable chemical environment in gel phase and Pickering stabilization described here is expected to prove useful for areas where proteins are to be exploited in technological contexts such as biocatalysis and also in other areas where protein performance and activity are important, such as biosensors and bioinspired solar fuel devices.

  17. Azelaic acid 15% gel: in the treatment of papulopustular rosacea.

    Science.gov (United States)

    Frampton, James E; Wagstaff, Antona J

    2004-01-01

    Azelaic acid is a naturally occurring, straight-chain dicarboxylic acid which is effective in the treatment of rosacea, presumably on account of its anti-inflammatory properties. In randomized, double-blind, multicenter studies involving patients with moderate papulopustular facial rosacea, twice-daily topical application of azelaic acid 15% gel to the face was significantly more effective than twice-daily administration of either its vehicle (two studies) or metronidazole 0.75% gel (one study) in reducing inflammatory lesion counts and erythema severity. However, neither active treatment had a clinically discernable effect on telangiectasia. In all three studies, azelaic acid 15% gel recipients experienced continuous decreases in lesion counts and erythema throughout the 12- to 15-week treatment periods. However, the effects of metronidazole 0.75% gel plateauxed after 8 weeks. In other efficacy assessments in these studies, azelaic acid 15% gel was superior to its vehicle and metronidazole 0.75% gel in both the investigators' global assessment of rosacea and the investigators' end-of-study evaluation of overall improvement, and superior to its vehicle in the patients' end-of-study evaluation of overall improvement. The most frequent treatment-related cutaneous adverse events during administration of azelaic acid 15% gel include burning/stinging/tingling and pruritus (itching); however, these events are predominantly transient in nature and mild-to-moderate in intensity.

  18. Emdogain-gel stimulates proliferation of odontoblasts and osteoblasts.

    Science.gov (United States)

    Jiang, Jin; Goodarzi, Golnaz; He, Jianing; Li, Haitao; Safavi, Kamran E; Spångberg, Larz S W; Zhu, Qiang

    2006-11-01

    The purpose of this study was to determine whether a premixed form of enamel matrix derivative (EMD), Emdogain-gel, has the same property as the original formula of EMD in stimulating the proliferation of osteoblasts and odontoblasts. Osteoblast cell line (MC3T3) and odontoblast cell line (MDPC) were cultured in the 6-well culture plates and treated in 4 different groups: (1) culture medium control, (2) 100 microg/mL Emdogain-gel directly added to the culture medium, (3) culture medium with a culture plate insert, and (4) 100 microg/mL Emdogain-gel added onto a culture plate insert. The culture plate insert prevented direct contact between Emdogain-gel and the cells. After 3-day incubation, cell morphology was examined and the total cell number per well was counted. Data were analyzed using 1-way ANOVA. Emdogain-gel significantly increased cell number of both osteoblasts and odontoblasts regardless the presence of the culture plate insert. Emdogain-gel stimulates cell proliferation of odontoblasts and osteoblasts. The direct contact between Emdogain-gel and cells is not required. Heat treatment of EMD and premix with propylene glycol alginate did not change its property of releasing bioactive molecules for promoting cell proliferation.

  19. Gel adsorption processing for waste solidification in NZP ceramics

    International Nuclear Information System (INIS)

    Yang, L.J.; Komareni, S.; Roy, R.

    1984-01-01

    Simulated PW-4b waste solution along with Na additive was mixed with Zr-P-O gel, dried and then fired to form the desired sodium zirconium phosphate, NaZr 2 (PO 4 ) 3 [NZP] ceramic. NZP and monazite were the only phases produced upon firing at 900 0 C with 10 to 40% of PW-4b mixed with the gel. CsZr 2 (PO 4 ) 3 which is isostructural with NZP was also identified when fired under reducing conditions. The -200 mesh powders of these waste forms prepared under reducing conditions showed excellent leach resistance under hydro-thermal conditions. Alternatively, PW-4b and Three Mile Island (TMI) wastes were adsorbed on Zr-P-O gel in a column. The gel was dried, pelletized and fired to form the desired [NZP] ceramic. Cesium was found to be selective on the Zr-P-O gel because no breakthrough of Cs was detected up to 38 column volumes of TMI waste. Thus, it is possible to use a tailored gel to sorb Cs and/or Sr from accident waste water and then fire the bed to form the [NZP] ceramic below 1000 0 C. The main advantages of the gel adsorption process are its simplicity and its enormous compositional flexibility. 12 references, 2 figures, 4 tables

  20. Development of strippable gel for surface decontamination applications

    International Nuclear Information System (INIS)

    Banerjee, D.; Sandhya, U.; Khot, S.A.; Srinivas, C.

    2015-07-01

    Strippable gels are an attractive option for decontamination of surfaces particularly when materials are to be reused after decontamination. The process in general results in good decontamination performance with minimal secondary waste generation. This paper reports on development of strippable gel formulation using polyvinyl alcohol as the gel former. Peeling behavior of the gel film improved when glycerol was used as plasticizer. Incorporation of decontaminating agents is essential for the gel to be effective, so a number of decontaminating agents were screened based on their miscibility with the gel, smooth peeling, and good decontamination performance. Based on this study, a strippable gel, ‘INDIGEL’ was formulated as a potential candidate for surface decontamination applications. Extensive trials on evaluation of decontamination performance of Indigel were done on simulated surfaces like stainless steel tray, stainless steel fume hood, PVC floor, granite and ceramic table tops. Results show that Indigel is highly effective for decontamination of surfaces contaminated with all types of radionuclides. Simplicity of its use coupled with good decontamination ability will find application in nuclear and other chemical industries. (author)

  1. Western Blot of Stained Proteins from Dried Polyacrylamide Gels

    Science.gov (United States)

    Gruber, Claudia; Stan-Lotter, Helga

    1996-01-01

    Western blotting of proteins is customarily performed following their separation on polyacrylamide gels, either prior to staining (1) or, as recently reported, following staining (2). We describe here Western blotting with stained gels, which had been dried and some of which had been stored for years. This procedure permits immunological analysis of proteins, to which antisera may have become available only later, or where the application of newly developed sensitive detection methods is desired. Once rehydration of the gels is achieved, proteins can be-transferred to blotting membranes by any appropriate protocol. Proteins stained with Coomassie Blue have to be detected with a non-chromogenic method, such as the film-based enhanced chemiluminescence (ECL)2) procedure (3). Silver stained proteins, which transfer in the colorless form, may be visualized by any detection method, although, because of the usually very low amounts of proteins, detection by ECL is preferable. Blotting of stained proteins from rehydrated gels is as rapid and as quantitative as from freshly prepared gels, in contrast to blotting from wet stained gels, which requires extensive washing and results in low transfer efficiency (2). Together with a photographic record of the gel pattern, unambiguous identification of immunoreactive proteins from complex mixtures is possible. Some further applications of this work are discussed.

  2. Gels composed of sodium-aluminum silicate, Lake Magadi, Kenya

    Science.gov (United States)

    Eugster, H.P.; Jones, B.F.

    1968-01-01

    Sodium-aluminum silicate gels are found in surftcial deposits as thick as 5 centimeters in the Magadi area of Kenya. Chemical data indicate they are formed by the interaction of hot alkaline springwaters (67?? to 82??C; pH, about 9) with alkali trachyte flows and their detritus, rather than by direct precipitation. In the process, Na2O is added from and silica is released to the saline waters of the springs. Algal mats protect the gels from erosion and act as thermal insulators. The gels are probably yearly accumulates that are washed into the lakes during floods. Crystallization of these gels in the laboratory yields analcite; this fact suggests that some analcite beds in lacustrine deposits may have formed from gels. Textural evidence indicates that cherts of rocks of the Pleistocene chert series in the Magadi area may have formed from soft sodium silicate gels. Similar gels may have acted as substrates for the accumulation and preservation of prebiological organic matter during the Precambrian.

  3. An apparatus for submerged gel electrophoresis.

    Science.gov (United States)

    Kozulić, B; Heimgartner, U

    1991-11-01

    A novel apparatus for submerged gel electrophoresis is described in detail. It includes an upper buffer compartment, a lower buffer compartment, and a horizontal plate between the two compartments. The horizontal plate is a heat exchanger connected to an external heater/cooler. Buffer circulates between the two compartments through openings in the horizontal plate. In the upper compartment two separated openings are positioned on each side of the horizontal plate between the side walls and long vertical barriers. The barriers initially direct the flow of buffer and define the electric field on the sides of the upper compartment. The electric field is confined essentially into a rectangular box, defined on the ends by the end walls, on the sides by the barriers, on the bottom by the cooling plate, and on the top by the air. Since the volume of buffer is smaller in the electrode compartment than in the reservoir under the cooling plate, this design enables formation of a substantially uniform electric field without creating too high a current. To enhance uniformity of the electric field, anode and cathode consist each of two platinum wires positioned one above the other at a distance of 6 mm. The electrodes can be placed parallel to the sides and perpendicular to the buffer flow or parallel to the ends and the flow of buffer. The stream of buffer in the upper compartment is regulated by two dams, perpendicular to the long barriers, on each end of the horizontal plate.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Drying and shrinkage of polymer gels

    Directory of Open Access Journals (Sweden)

    S. S. Waje

    2005-06-01

    Full Text Available The polymer hydrogel was synthesized by photo-polymerization process (UV light, 60 ºC in presence of Photo-initiator (IrgacureR and Cross-linker (NN'-methylene bisacrylamide; MBAM. In the present work, the drying of polymer hydrogel was carried out to study the effect of temperature, gel-sheet thickness, monomer ratio of acryl acid to acrylamide (AA/AM, concentration of MBAM and quantity of monomers. A correlation has been developed for modified sheet thickness as a function of contraction coefficient and degree of drying. Effective diffusivity was estimated from Fickian-diffusive model considering modified sheet thickness and was found to be in the range of 1.1 ´ 10-10-5.93 ´ 10-10 m²/s. The activation energy obtained using Arrhenius type equation was found to be in the range of 2979-10737 kJ/kmol H2O. The drying behavior shows an initial shoot-up in drying rate followed by constant rate and two falling rate periods.

  5. Implementation of MRI gel dosimetry in radiation therapy

    International Nuclear Information System (INIS)

    Baeck, S.Aa.J.

    1998-12-01

    Gel dosimetry was used together with magnetic resonance imaging (MRI) to measure three-dimensional absorbed dose distributions in radiation therapy. Two different dosimeters were studied: ferrous- and monomer gel, based on the principles of radiation-induced oxidation and polymerisation, respectively. Single clinical electron and photon beams were evaluated and gel dose distributions were mainly within 2% of conventional detector results. The ferrous-gel was also used for clinical proton beams. A decrease in signal per absorbed dose was found close to the end of the range of the protons (15-20%). This effect was explained as a linear energy transfer dependence, further supported with Monte Carlo simulations. A method for analysing and comparing data from treatment planning system (TPS) and gel measurements was developed. The method enables a new pixel by pixel evaluation, isodose comparison and dose volume histogram verification. Two standard clinical radiation therapy procedures were examined using the developed TPS verification method. The treatment regimes included several beams of different radiation qualities. The TPS calculated data were in very good agreement with the dose distribution measured by the ferrous-gel. However, in a beam abutment region, larger dose difference was found. Beam adjustment errors and a minor TPS underestimation of the lateral scatter contribution outside the primary electron beam may explain the discrepancy. The overall uncertainty in the ferrous-gel dose determination was considerably reduced using an optimised MRI acquisition protocol and a new MRI scanner. The relative dose uncertainty was found to be better than 3.3% for all dose levels (95% confidence level). Using the method developed for comparing measured gel data with calculated treatment plans, the gel dosimetry method was proven to be a useful tool for radiation treatment planning verification

  6. Implementation of MRI gel dosimetry in radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Baeck, S.Aa.J

    1998-12-01

    Gel dosimetry was used together with magnetic resonance imaging (MRI) to measure three-dimensional absorbed dose distributions in radiation therapy. Two different dosimeters were studied: ferrous- and monomer gel, based on the principles of radiation-induced oxidation and polymerisation, respectively. Single clinical electron and photon beams were evaluated and gel dose distributions were mainly within 2% of conventional detector results. The ferrous-gel was also used for clinical proton beams. A decrease in signal per absorbed dose was found close to the end of the range of the protons (15-20%). This effect was explained as a linear energy transfer dependence, further supported with Monte Carlo simulations. A method for analysing and comparing data from treatment planning system (TPS) and gel measurements was developed. The method enables a new pixel by pixel evaluation, isodose comparison and dose volume histogram verification. Two standard clinical radiation therapy procedures were examined using the developed TPS verification method. The treatment regimes included several beams of different radiation qualities. The TPS calculated data were in very good agreement with the dose distribution measured by the ferrous-gel. However, in a beam abutment region, larger dose difference was found. Beam adjustment errors and a minor TPS underestimation of the lateral scatter contribution outside the primary electron beam may explain the discrepancy. The overall uncertainty in the ferrous-gel dose determination was considerably reduced using an optimised MRI acquisition protocol and a new MRI scanner. The relative dose uncertainty was found to be better than 3.3% for all dose levels (95% confidence level). Using the method developed for comparing measured gel data with calculated treatment plans, the gel dosimetry method was proven to be a useful tool for radiation treatment planning verification 103 refs, 20 figs, 6 tabs

  7. SPI Conformance Gel Applications in Geothermal Zonal Isolation

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Lyle [Clean Tech Innovations, Bartlesville, OK (United States)

    2017-08-08

    Zonal isolation in geothermal injection and producing wells is important while drilling the wells when highly fractured geothermal zones are encountered and there is a need to keep the fluids from interfering with the drilling operation. Department of Energy’s (DOE) Energy Efficiency and Renewable Energy (EERE) objectives are to advance technologies to make it more cost effective to develop, produce, and monitor geothermal reservoirs and produce geothermal energy. Thus, zonal isolation is critical to well cost, reservoir evaluation and operations. Traditional cementing off of the lost circulation or thief zones during drilling is often done to stem the drilling mud losses. This is an expensive and generally unsuccessful technique losing the potential of the remaining fracture system. Selective placement of strong SPI gels into only the offending fractures can maintain and even improve operational efficiency and resource life. The SPI gel system is a unique silicate based gel system that offers a promising solution to thief zones and conformance problems with water and CO2 floods and potentially geothermal operations. This gel system remains a low viscosity fluid until an initiator (either internal such as an additive or external such as CO2) triggers gelation. This is a clear improvement over current mechanical methods of using packers, plugs, liners and cementing technologies that often severely damage the highly fractured area that is isolated. In the SPI gels, the initiator sets up the fluid into a water-like (not a precipitate) gel and when the isolated zone needs to be reopened, the SPI gel may be removed with an alkaline solution without formation damage occurring. In addition, the SPI gel in commercial quantities is expected to be less expensive than competing mechanical systems and has unique deep placement possibilities. This project seeks to improve upon the SPI gel integrity by modifying the various components to impart temperature stability for use in

  8. RNA conformational changes analyzed by comparative gel electrophoresis.

    Science.gov (United States)

    Eschbach, Sébastien H; Lafontaine, Daniel A

    2014-01-01

    The study of biologically relevant native RNA structures is important to understand their cellular function(s). Native gel electrophoresis provides information about such native structures in solution as a function of experimental conditions. The application of native gel electrophoresis in a comparative manner allows to obtain precise information on relative angles subtended between given pair of stems in an RNA molecule. By adapting this approach, it is possible to obtain very specific structural information such as the amplitude of dihedral angles and helical rotation. As an example, we will describe how native gel electrophoresis can be used to study the folding of the S-adenosylmethionine (SAM) sensing riboswitch.

  9. Purification of radiolabeled RNA products using denaturing gel electrophoresis.

    Science.gov (United States)

    Adachi, Hironori; Yu, Yi-Tao

    2014-01-06

    This unit discusses a basic method for purification of radiolabeled RNAs using denaturing polyacrylamide gel electrophoresis. The method consists of a number of experimental procedures, including total RNA preparation from yeast cells, isolation of a specific RNA from total yeast RNA, RNA 3'-terminal labeling using nucleotide (5' [(32) P]pCp) addition (via ligation), denaturing (8 M urea) polyacrylamide gel electrophoresis, and RNA extraction from the gel slice. Key points for achieving good electrophoretic separation of RNA are also discussed. Copyright © 2014 John Wiley & Sons, Inc.

  10. Hydrogen peroxide agarose gels for electrophoretic analysis of RNA.

    Science.gov (United States)

    Pandey, Renu; Saluja, Daman

    2017-10-01

    Efficient electrophoretic separation of isolated total RNA utilizes chemicals and agents to aid in nuclease free environment. However cost, extensive pre-run processing protocols as well as toxic byproducts limit the usage of such protocols. Moreover, these treatments affect the overall electrophoretic results by altering the conductivity of the running buffer and weaken the gel strength. We here provide a protocol for RNA visualization that obviates these shortcomings by preparation of agarose gel with hydrogen peroxide using the regular TAE buffer. The simple, inexpensive protocol exhibits superior results in a horizontal agarose gel electrophoresis. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Tensile Properties of Poly (N-vinyl caprolactam) Gels

    Science.gov (United States)

    Morgret, Leslie D.; Hinkley, Jeffrey A.

    2004-01-01

    N-vinyl caprolactam was copolymerized with ethylene glycol dimethacrylate using a free-radical initiator in alcohol/water solution. The resulting gels were thermally-responsive in water, undergoing an approximate fivefold reversible volume shrinkage between room temperature and ca. 50 C. Tensile testing showed that the stress-strain behavior was qualitatively different in the collapsed state above the temperature-induced transition. At the higher temperature, gels were stiffer, more ductile, and showed greater time dependence. Implications for the design of gel actuators are briefly discussed.

  12. Sol-gel processing with inorganic metal salt precursors

    Science.gov (United States)

    Hu, Zhong-Cheng

    2004-10-19

    Methods for sol-gel processing that generally involve mixing together an inorganic metal salt, water, and a water miscible alcohol or other organic solvent, at room temperature with a macromolecular dispersant material, such as hydroxypropyl cellulose (HPC) added. The resulting homogenous solution is incubated at a desired temperature and time to result in a desired product. The methods enable production of high quality sols and gels at lower temperatures than standard methods. The methods enable production of nanosize sols from inorganic metal salts. The methods offer sol-gel processing from inorganic metal salts.

  13. Azelaic acid (15% gel) in the treatment of acne rosacea.

    Science.gov (United States)

    Gupta, Aditya K; Gover, Melissa D

    2007-05-01

    In December of 2002, the FDA approved azelaic acid 15% gel for the topical treatment of inflammatory papules and pustules of mild to moderate rosacea. Azelaic acid is a saturated dicarboxylic acid, which is naturally occurring and has been used in the treatment of rosacea, acne, and melasma. The 15% gel has a high efficacy and is generally well tolerated, with the local irritation (burning, stinging, itching, and scaling) being typically mild and transient. Azelaic acid 15% gel is considered effective and safe as a therapy for inflammatory papulo-pustular rosacea and is suitable for use on all skin types.

  14. Actin purification from a gel of rat brain extracts.

    Science.gov (United States)

    Levilliers, N; Peron-Renner, M; Coffe, G; Pudles, J

    1984-01-01

    Actin, 99% pure, has been recovered from rat brain with a high yield (greater than 15 mg/100 g brain). We have shown that: 1. a low ionic strength extract from rat brain tissue is capable of giving rise to a gel; 2. actin is the main gel component and its proportion is one order of magnitude higher than in the original extract; 3. actin can be isolated from this extract by a three-step procedure involving gelation, dissociation of the gel in 0.6 M KCl, followed by one or two depolymerization-polymerization cycles.

  15. ADSORPSI Cr(III PADA SILIKA GEL TERMODIFIKASI DIFENILKARBAZON SECARA SOL-GEL

    Directory of Open Access Journals (Sweden)

    Ida Ayu Raka Astiti Asih

    2016-06-01

    Full Text Available ABSTRAK : Telah dilakukan penelitian mengenai pemanfaatan silika gel termodifikasi difenilkarbazon (Si-CPTMS-DPZon secara sol-gel untuk mengadsorpsi ion logam kromium(III.  Studi adsorpsi  dilakukan  dengan metode Batch. Pengaruh waktu dan pH awal larutan kromium dipelajari untuk mendapatkan kondisi optimum adsorpsi dan variasi konsentrasi ion kromium digunakan untuk mendapatkan kapasitas adsorpsi. Model isotermal Langmuir dan Freundlich digunakan untuk menentukan isoterm adsorpsi. Hasil penelitian menunjukkan bahwa adsorpsi Cr(III pada adsorben Si-CPTMS-DPZon optimum terjadi pada pH 4 dan waktu interaksi 90 menit, dengan kapasitas adsorpsi sebesar 36,28 mg/g dan energi adsorpsi sebesar 29,16 kJ/mol. Adsorpsi yang terjadi lebih cenderung mengikuti isoterm Langmuir dengan nilai R2 sebesar 0,9971 dibanding dengan isoterm Freundlich dengan R2 0,5612.  Adsorpsi Cr(III pada adsorben dominan melalui adsorpsi kimia.     ABSTRACT : Research about utilizing of diphenylcarbazone-modified silica gel prepared by sol-gel method (Si-CPTMS-DPZon to adsorp chromium (III ions has been carried out. This study was conducted using batch adsorption. The influence of time and initial pH of chromium solution were studied to obtain the optimum adsorption conditions, and the variation of the concentration of chromium ion was used to obtain the adsorption capacity. Langmuir and Freundlich isotherm models were used to determine the model of isotherm adsorption. The results showed that the optimum adsorption of Cr (III on the adsorbent Si-CPTMS-DPZ occurred at pH 4 with 90 minutes of contact time. The adsorption capacity of Cr(III on Si-CPTMS-DPZ was 36.28 mg/g with the adsorption energy of 29.16 kJ/mol. The adsorption profile tends to follow the Langmuir isotherm with R2 values of 0.9971 rather than the Freundlich isotherm with R2 of 0.5612. Adsorption of Cr (III on the adsorbent dominantly occurred through chemical adsorption.

  16. Bi-Sr-Co-O thermoelectrics prepared by sol-gel methods with modified gel decomposition

    Czech Academy of Sciences Publication Activity Database

    Rubešová, K.; Hlásek, T.; Jakeš, V.; Sedmidubský, D.; Hejtmánek, Jiří

    2012-01-01

    Roč. 30, č. 1 (2012), 1-5 ISSN 1757-8981. [Fall Meeting of the European-Materials-Research-Society (E-MRS)/Symposium K - Solution-Derived Electronic-Oxide Films, Nanostructures and Patterning, from Materials to Devices. Warsaw, 19.09.2011-23.09.2011] R&D Projects: GA ČR GA203/09/1036 Institutional research plan: CEZ:AV0Z10100521 Keywords : BiSrCoO * thermoelectrics * sol–gel Subject RIV: BM - Solid Matter Physics ; Magnetism

  17. Gel and gel-free approaches for the quantitative characterisation of complex protein mixtures

    CSIR Research Space (South Africa)

    Buthelezi, S

    2012-10-01

    Full Text Available When using proteomics as a tool to discover biomarkers, selecting a fractionation method to be used prior to mass spectrometric analysis is crucial. DISCUSSION AND CONCLUSION The 7 cm 2DE gel was the cheapest to run no matter which stain.... REFERENCES 1. Han, X., Aslanian, A. and Yates III, J.R. Mass spectrometry for proteomics. Curr Opin Chem Biol 2008 10;12(5):483-490. 2. Janini, G.M., Conrads, T.P., Veenstra, T.D. and Issaq, H.J. Development of a two- dimensional protein...

  18. Lidocaine gel versus plain lubricating gel for pain reduction during transrectal sonography (LIPS): A randomized controlled trial.

    Science.gov (United States)

    Nam, Su Hyun; Kim, Kye Hyun; Choi, Chahien; Nam, Se Hyun; Song, Taejong; Lee, Kyo Won

    2017-05-01

    To compare the efficacy and safety of lidocaine gel and plain lubricating gel in relieving pain during transrectal sonography (TRS) in patients with gynecologic problems. A randomized controlled trial was conducted in 80 participants who were scheduled to undergo TRS. The participants were allocated into the lidocaine gel group and the aqueous gel group at a 1:1 ratio. The intensity of pain during TRS based on the visual analogue scale (0-10 points) and the adverse events were assessed and compared between the two groups. The two groups had similar demographic characteristics. Between the lidocaine and aqueous gel groups, there was no significant difference in the pain score at probe manipulation (4.04±2.14 vs. 4.21±2.79; P=0.868), as well as at baseline, probe insertion, and 5min after probe removal. The degree of acceptability of the sonographer also did not differ between the two groups. No acute and delayed adverse events was occurred. Intrarectal lidocaine gel for TRS provides no analgesic benefit compared with aqueous gel. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Investigation of preparation and mechanisms of a dispersed particle gel formed from a polymer gel at room temperature.

    Directory of Open Access Journals (Sweden)

    Guang Zhao

    Full Text Available A dispersed particle gel (DPG was successfully prepared from a polymer gel at room temperature. The polymer gel system, morphology, viscosity changes, size distribution, and zeta potential of DPG particles were investigated. The results showed that zirconium gel systems with different strengths can be cross-linked within 2.5 h at low temperature. Scanning electron microscopy (SEM, transmission electron microscopy (TEM, and atomic force microscopy (AFM results showed that the particles were polygonal particles with nano-size distribution. According to the viscosity changes, the whole preparation process can be divided into two major stages: the bulk gel cross-linking reaction period and the DPG particle preparation period. A polymer gel with a 3-dimensional network was formed in the bulk gel cross-linking reaction period whereas shearing force and frictional force were the main driving forces for the preparation of DPG particles, and thus affected the morphology of DPG particles. High shearing force and frictional force reduced the particle size distribution, and then decreased the zeta potential (absolute value. The whole preparation process could be completed within 3 h at room temperature. It could be an efficient and energy-saving technology for preparation of DPG particles.

  20. Integration of gel-based and gel-free proteomic data for functional analysis of proteins through Soybean Proteome Database

    KAUST Repository

    Komatsu, Setsuko

    2017-05-10

    The Soybean Proteome Database (SPD) stores data on soybean proteins obtained with gel-based and gel-free proteomic techniques. The database was constructed to provide information on proteins for functional analyses. The majority of the data is focused on soybean (Glycine max ‘Enrei’). The growth and yield of soybean are strongly affected by environmental stresses such as flooding. The database was originally constructed using data on soybean proteins separated by two-dimensional polyacrylamide gel electrophoresis, which is a gel-based proteomic technique. Since 2015, the database has been expanded to incorporate data obtained by label-free mass spectrometry-based quantitative proteomics, which is a gel-free proteomic technique. Here, the portions of the database consisting of gel-free proteomic data are described. The gel-free proteomic database contains 39,212 proteins identified in 63 sample sets, such as temporal and organ-specific samples of soybean plants grown under flooding stress or non-stressed conditions. In addition, data on organellar proteins identified in mitochondria, nuclei, and endoplasmic reticulum are stored. Furthermore, the database integrates multiple omics data such as genomics, transcriptomics, metabolomics, and proteomics. The SPD database is accessible at http://proteome.dc.affrc.go.jp/Soybean/. Biological significanceThe Soybean Proteome Database stores data obtained from both gel-based and gel-free proteomic techniques. The gel-free proteomic database comprises 39,212 proteins identified in 63 sample sets, such as different organs of soybean plants grown under flooding stress or non-stressed conditions in a time-dependent manner. In addition, organellar proteins identified in mitochondria, nuclei, and endoplasmic reticulum are stored in the gel-free proteomics database. A total of 44,704 proteins, including 5490 proteins identified using a gel-based proteomic technique, are stored in the SPD. It accounts for approximately 80% of all

  1. Integration of gel-based and gel-free proteomic data for functional analysis of proteins through Soybean Proteome Database.

    Science.gov (United States)

    Komatsu, Setsuko; Wang, Xin; Yin, Xiaojian; Nanjo, Yohei; Ohyanagi, Hajime; Sakata, Katsumi

    2017-06-23

    The Soybean Proteome Database (SPD) stores data on soybean proteins obtained with gel-based and gel-free proteomic techniques. The database was constructed to provide information on proteins for functional analyses. The majority of the data is focused on soybean (Glycine max 'Enrei'). The growth and yield of soybean are strongly affected by environmental stresses such as flooding. The database was originally constructed using data on soybean proteins separated by two-dimensional polyacrylamide gel electrophoresis, which is a gel-based proteomic technique. Since 2015, the database has been expanded to incorporate data obtained by label-free mass spectrometry-based quantitative proteomics, which is a gel-free proteomic technique. Here, the portions of the database consisting of gel-free proteomic data are described. The gel-free proteomic database contains 39,212 proteins identified in 63 sample sets, such as temporal and organ-specific samples of soybean plants grown under flooding stress or non-stressed conditions. In addition, data on organellar proteins identified in mitochondria, nuclei, and endoplasmic reticulum are stored. Furthermore, the database integrates multiple omics data such as genomics, transcriptomics, metabolomics, and proteomics. The SPD database is accessible at http://proteome.dc.affrc.go.jp/Soybean/. The Soybean Proteome Database stores data obtained from both gel-based and gel-free proteomic techniques. The gel-free proteomic database comprises 39,212 proteins identified in 63 sample sets, such as different organs of soybean plants grown under flooding stress or non-stressed conditions in a time-dependent manner. In addition, organellar proteins identified in mitochondria, nuclei, and endoplasmic reticulum are stored in the gel-free proteomics database. A total of 44,704 proteins, including 5490 proteins identified using a gel-based proteomic technique, are stored in the SPD. It accounts for approximately 80% of all predicted proteins from

  2. Strain identification in Rhizobium by starch gel electrophoresis of isoenzymes

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen; Nielsen, G.

    1985-01-01

    Sonieated extracts of rhizobia, especiaUy Rhizobium leguminosarum from pea and vetch, were run in horizontal starch gel electrophoresis in the cold. The rhizobia were grown on agar on a slime suppressing substrate of tryptone-yeast extract-CaCl2 with small amounts of mannitol, sorbitol and arabin......Sonieated extracts of rhizobia, especiaUy Rhizobium leguminosarum from pea and vetch, were run in horizontal starch gel electrophoresis in the cold. The rhizobia were grown on agar on a slime suppressing substrate of tryptone-yeast extract-CaCl2 with small amounts of mannitol, sorbitol...... and arabinose and other sugars as enzyme inducers. After electrophoresis the gels were separated into several slabs by a gel cutter. Each slab was stained for a particular enzyme. Among numerous enzyme systems tested we found useful variation in esterases (EC 3.1.1.1, EC 3.1.1.2), 3-hydroxybutyrate...

  3. Rheological properties of magneto-responsive copolymer gels

    NARCIS (Netherlands)

    An, H.

    2012-01-01

    New magneto rheological systems that respond mechanically to external homogeneous magnetic fields, namely, physically cross-linked magneto rheological (MR) gels, were synthesized and investigated. Various aspects of the rheological behavior were considered such as linear viscoelastic response for

  4. Studies on supramolecular gel formation using DOSY NMR

    Czech Academy of Sciences Publication Activity Database

    Nonappa, N.; Šaman, David; Kolehmainen, E.

    2015-01-01

    Roč. 53, č. 4 (2015), s. 256-260 ISSN 0749-1581 Institutional support: RVO:61388963 Keywords : DOSY * VT NMR * gel * diffusion coefficients Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.226, year: 2015

  5. Poroelastic toughening in polymer gels: A theoretical and numerical study

    Science.gov (United States)

    Noselli, Giovanni; Lucantonio, Alessandro; McMeeking, Robert M.; DeSimone, Antonio

    2016-09-01

    We explore the Mode I fracture toughness of a polymer gel containing a semi-infinite, growing crack. First, an expression is derived for the energy release rate within the linearized, small-strain setting. This expression reveals a crack tip velocity-independent toughening that stems from the poroelastic nature of polymer gels. Then, we establish a poroelastic cohesive zone model that allows us to describe the micromechanics of fracture in gels by identifying the role of solvent pressure in promoting poroelastic toughening. We evaluate the enhancement in the effective fracture toughness through asymptotic analysis. We confirm our theoretical findings by means of numerical simulations concerning the case of a steadily propagating crack. In broad terms, our results explain the role of poroelasticity and of the processes occurring in the fracturing region in promoting toughening of polymer gels.

  6. Observation of a microcrystalline gel in colloids with competing interactions.

    Science.gov (United States)

    Zhang, Tian Hui; Groenewold, Jan; Kegel, Willem K

    2009-12-14

    A stable short-range crystalline structure is observed in colloidal systems with competing short-range attractions and long-range repulsions. We term these structures "microcrystalline gels" as the microcrystals are embedded in a dense disordered network.

  7. Reproducibility and signal response linearity of Alanine gel dosimeter

    International Nuclear Information System (INIS)

    Silva, Cleber Feijo Silva; Campos, Leticia Lucente

    2008-01-01

    Gel Dosimetry has been studied mainly for medical applications, because it presents signal response in the dose range used in radiotherapy treatments and it can be applied for three dimensional dosimetry. Alanine gel dosimeter is a new gel material developed at IPEN that presents significant improvement on previous alanine systems developed by Costa (1994). The DL-Alanine (C 3 H 7 NO 2 ) is an amino acid tissue equivalent that improves the production of ferric ions in the solution. These ferric ions concentration can be measured by spectrophotometry technique. This work aims to study the reproducibility of the alanine gel solutions and the signal response as a function of gamma radiation dose, considering that these two properties are very important for characterizing and standardizing any dosimeter. (author)

  8. Superabsorbing gel for actinide, lanthanide, and fission product decontamination

    Science.gov (United States)

    Kaminski, Michael D.; Mertz, Carol J.

    2016-06-07

    The present invention provides an aqueous gel composition for removing actinide ions, lanthanide ions, fission product ions, or a combination thereof from a porous surface contaminated therewith. The composition comprises a polymer mixture comprising a gel forming cross-linked polymer and a linear polymer. The linear polymer is present at a concentration that is less than the concentration of the cross-linked polymer. The polymer mixture is at least about 95% hydrated with an aqueous solution comprising about 0.1 to about 3 percent by weight (wt %) of a multi-dentate organic acid chelating agent, and about 0.02 to about 0.6 molar (M) carbonate salt, to form a gel. When applied to a porous surface contaminated with actinide ions, lanthanide ions, and/or other fission product ions, the aqueous gel absorbs contaminating ions from the surface.

  9. Charged acrylamide copolymer gels as media for weak alignment

    International Nuclear Information System (INIS)

    Meier, Sebastian; Haeussinger, Daniel; Grzesiek, Stephan

    2002-01-01

    The use of mechanically strained acrylamide/acrylate copolymers is reported as a new alignment medium for biomacromolecules. Compared to uncharged, strained polyacrylamide gels, the negative charges of the acrylamide/acrylate copolymer strongly alter the alignment tensor and lead to pronounced electroosmotic swelling. The swelling itself can be used to achieve anisotropic, mechanical strain. The method is demonstrated for the alignment of TipAS, a 17 kDa antibiotic resistance protein, as well as for human ubiquitin, where alignment tensors with an A ZZ,NH of up to 60 Hz are achieved at a gel concentration of 2% (w/v). The alignment can be modulated by the variation of pH, ionic strength, and gel concentration. The high mechanical stability of the swollen gels makes it possible to obtain alignment at polymer concentrations of less than 1% (w/v)

  10. Correlation between ionic conductivity and fluidity of polymer gel ...

    Indian Academy of Sciences (India)

    Unknown

    PMMA) as the gelling polymer have been studied. Conductivity, pH and viscosity of liquid and polymer gel electrolytes have been studied as functions of salt concentration, polymer concentration and temperature. FTIR studies have also been ...

  11. Formulation and Permeation Kinetic Studies of Flurbiprofen Gel

    African Journals Online (AJOL)

    9-11]. The objective of this study was to investigate the permeation and drug release kinetics flurbiprofen gels using silicone membrane in modified Franz diffusion cells with the aid of surface response methodology. EXPERIMENTAL. Materials.

  12. Sol-gel materials for optofluidics - process and applications

    DEFF Research Database (Denmark)

    Mikkelsen, Morten Bo Lindholm

    2011-01-01

    This Ph.D. thesis is concerned with the use of sol-gel materials in optofluidic applications and the physics of DNA molecules in nanoconfinement. The bottom-up formation of solid material, which is provided by the sol-gel process, enables control of the chemical composition and porosity of the ma......This Ph.D. thesis is concerned with the use of sol-gel materials in optofluidic applications and the physics of DNA molecules in nanoconfinement. The bottom-up formation of solid material, which is provided by the sol-gel process, enables control of the chemical composition and porosity...... high-vacuum techniques. Sealing of the channels was performed by fusion bonding of a glass cover slip to the imprinted surface, and the applicability of the device was demonstrated by sizing experiments on DNA molecules confined in the imprinted nanochannels. In addition, in a fused silica device...

  13. Safe and Environmentally Acceptable Sol-Gel-Derived Pyrophoric Pyrotechnics

    National Research Council Canada - National Science Library

    Simpson, Randall L; Hubble, William; Stevenson, Bradley; Gash, Alexander; Satcher, Joe; Metcalf, Patricia

    2004-01-01

    It was demonstrated that highly porous sol-gel derived iron (III) oxide materials could be reduced to sub-micron-sized metallic iron by heating the materials to intermediate temperatures in a hydrogen atmosphere...

  14. Sol-Gel Derived, Nanostructured Oxide Lubricant Coatings

    National Research Council Canada - National Science Library

    Taylor, Douglas

    2000-01-01

    In this program, we deposited oxide coatings of titanium and nickel by wet-chemical deposition methods, also referred to as sol-gel, which showed excellent tribological properties in previous investigations...

  15. Magneto-dependent stress relaxation of magnetorheological gels

    KAUST Repository

    Xu, Yangguang

    2017-09-01

    The stress relaxation behaviors of magnetorheological (MR) gels under stepwise shear loading are systematically investigated. The particle-enhanced effect, the magneto-induced effect, and the temperature-enhanced effect on the stress relaxation of MR gels are discussed. For further analysis of the magneto-induced stress relaxation mechanism in MR gels, a phenomenological model is established to describe the stress relaxation behavior of the matrix and the magnetic particle chains. All characteristic parameters introduced in the model, i.e. relaxation time, instantaneous modulus, and stable modulus, have well-defined physical meanings and are fitted based on the experimental results. The influence of each parameter on the macroscopic response is discussed and it is found that the relaxation stress induced by the magneto-mechanical coupling effect plays an important role in the stress relaxation process of MR gels.

  16. Using Gel Electrophoresis To Illustrate Protein Diversity and Isoelectric Point.

    Science.gov (United States)

    Browning, Mark; Vanable, Joseph

    2002-01-01

    Demonstrates the differences in protein structures by focusing on isoelectric point with an experiment that is observable under certain pH levels in gel electrophoresis. Explains the electrophoresis procedure and reports results of the experiments. (YDS)

  17. Growth, characterization and dielectric property studies of gel grown ...

    Indian Academy of Sciences (India)

    Administrator

    The supernatant solution, BaCl2 diffuses into the gel column and reacts with succinic acid in the gel, producing the necessary supersaturation for the slow precipitation of. BaC4H4O4. When the concentration of the diffusant is optimum, a few critical-sized nuclei are produced and due to the subsequent diffusion of BaCl2, ...

  18. Uptake and Recovery of Lead by Agarose Gel Polymers

    OpenAIRE

    Anurag Pandey; Anupam Shukla; Lalitagauri Ray

    2009-01-01

    Problem statement: The uptake and recovery of lead ions were investigated by using agarose gel polymers. Approach: The experimental results showed that the agarose gel were effective in removing Pb (II) from solution. Biosorption equilibrium was approached within 4 h. Pseudo second-order was applicable to all the sorption data over the entire time range. Results: The sorption data conformed well to both the Langmuir and the Freundlich isotherm model. The ma...

  19. Antifungal activity of aloe vera gel against plant pathogenic fungi

    International Nuclear Information System (INIS)

    Sitara, U.; Hassan, N.; Naseem, J.

    2011-01-01

    Aloe vera gel extracted from the Aloe vera leaves was evaluated for their antifungal activity at the rate of 0.15%, 0.25% and 0.35% concentration against five plants pathogenic fungi viz., Aspergillus niger, Aspergillus flavus, Alternaria alternata, Drechslera hawaiensis and Penicillum digitatum 0.35% concentration Aloe vera gel completely inhibited the growth of Drechslera hawaiensis and Alternaria alternata. (author)

  20. Lattice variation and thermal parameters of gel grown KDP crystals ...

    Indian Academy of Sciences (India)

    Pure and impurity added (with NH4Cl, NH4NO3, NH4H2PO4, and (NH4)2SO4) KDP single crystals were grown by the gel method using silica gels. X-ray diffraction data were collected for powder samples and used for the estimation of lattice variation and thermal parameters like Debye–Waller factor, mean-square ...

  1. Uncertainty Analysis in MRI-based Polymer Gel Dosimetry

    Directory of Open Access Journals (Sweden)

    Keshtkar M.

    2017-09-01

    Full Text Available Background: Polymer gel dosimeters combined with magnetic resonance imaging (MRI can be used for dose verification of advanced radiation therapy techniques. However, the uncertainty of dose map measured by gel dosimeter should be known. The purpose of this study is to investigate the uncertainty related to calibration curve and MRI protocol for MAGIC (Methacrylic and Ascorbic acid in Gelatin Initiated by Copper gel and finally ways of optimization MRI protocol is introduced. Materials and Methods: MAGIC gel was prepared by the Fong et al. instruction. The gels were poured into calibration vials and irradiated by 18 MV photons. 1.5 Tesla MRI was used for reading out information. Finally, uncertainty of measured dose was calculated. Results: Results show that for MAGIC polymer gel dosimeter, at low doses, the estimated uncertainty is high (≈ 18.96% for 1 Gy but it reduces to approximately 4.17% for 10 Gy. Also, with increasing dose, the uncertainty for the measured dose decreases non-linearly. For low doses, the most significant uncertainties are σR0 (uncertainty of intercept and σa (uncertainty of slope for high doses. MRI protocol parameters influence signal-to-noise ratio (SNR. Conclusion: The most important source of uncertainty is uncertainty of R2. Hence, MRI protocol and parameters therein should be optimized. At low doses, the estimated uncertainty is high and reduces by increasing dose. It is suggested that in relative dosimetry, gels are irradiated by high doses in linear range of given gel dosimeter and then scaled down to the desired dose range.

  2. Steady-state leaching of tritiated water from silica gel

    DEFF Research Database (Denmark)

    Das, H.A.; Hou, Xiaolin

    2009-01-01

    Aqueous leaching of tritium from silica gel, loaded by absorption of water vapor, makes part of reactor de-commissioning. It is found to follow the formulation of steady-state diffusion.......Aqueous leaching of tritium from silica gel, loaded by absorption of water vapor, makes part of reactor de-commissioning. It is found to follow the formulation of steady-state diffusion....

  3. А new factor effecting gel strength of pectin polysaccharides

    Directory of Open Access Journals (Sweden)

    S. E. Kholov

    2016-01-01

    Full Text Available Pectin polysaccharides obtained from various raw materials have a different component composition and form gels with water, sugar and acid or calcium. In this study, an experimental approach the gelation properties of different pectin samples, varied from different sources, using new methods of hydrolysis and purification. Samples were obtained by hydrolysis of accelerated extraction of pectin and purified by diaultrfiltration, have a high gel strength. The highest gel strength have been found in series of high methoxyl (HM- pectin samples of apple, peach, orange and low methoxyl (LM- pectin samples of commercial citrus pectin and apple pectin obtained by new method. It is shown that in addition to the basic parameters (the content of galacturonic acid, degree of esterification, molecular weight and hidrodinamic radius macromolecule to affect gel strength pectins aggregation of macromolecules, which is determined by the z-average molecular weight. There were observed a clear pattern of the influence of the molecular weight on hydrodynamic parameters for both HM- and LM- pectin samples on the gel strength. It were shown that a high values of molecular weight, intrinsic viscosity, and radius of gyration of pectin samples can significantly increase gel strength, while the value of Mz oppositely influenced the gel strength. As a result, a systematic analysis of this parameter and its relationship to the average molecular weight found that indeed the ratio Mz/Mw for pectin’s is an crucial to assess the quality of pectin at the study of gel strength for pectin polysaccharides.

  4. Anti-arthritic effects of microneedling with bee venom gel

    OpenAIRE

    Mengdi Zhao; Jie Bai; Yang Lu; Shouying Du; Kexin Shang; Pengyue Li; Liu Yang; Boyu Dong; Ning Tan

    2016-01-01

    Objective: To combine with transdermal drug delivery using microneedle to simulate the bee venom therapy to evaluate the permeation of bee venom gel. Methods: In this study, the sodium urate and LPS were used on rats and mice to construct the model. Bee venom gel–microneedle combination effect on the model is to determine the role of microneedle gel permeation by observing inflammation factors. Results: Compared with the model group, the bee venom gel–microneedle combination group can r...

  5. Rapid DNA sequencing by horizontal ultrathin gel electrophoresis.

    OpenAIRE

    Brumley, R L; Smith, L M

    1991-01-01

    A horizontal polyacrylamide gel electrophoresis apparatus has been developed that decreases the time required to separate the DNA fragments produced in enzymatic sequencing reactions. The configuration of this apparatus and the use of circulating coolant directly under the glass plates result in heat exchange that is approximately nine times more efficient than passive thermal transfer methods commonly used. Bubble-free gels as thin as 25 microns can be routinely cast on this device. The appl...

  6. Multifunctional gels from polymeric spin-crossover metallo-gelators.

    Science.gov (United States)

    Grondin, Pauline; Roubeau, Olivier; Castro, Miguel; Saadaoui, Hassan; Colin, Annie; Clérac, Rodolphe

    2010-04-06

    The gelation abilities toward organic solvents of a series of triazole-based coordination polymers of formula [M(C(n)trz)(3)]A(2) (M = Fe(II) or Zn(II); C(n)trz = 4-n-alkyl-1,2,4-triazole with n = 13, 16, 18; A = monovalent anions, abbreviated as MC(n)A) have been studied to form thermally responsive multifunctional metallogels, in particular for the iron polymers that present the spin-crossover phenomenon. Indeed thermo-reversible physical gels exhibiting thermally reversible magnetic and optical crossovers are formed in decane and toluene. The FeC(18)ptol/decane and FeC(18)ptol/toluene phase diagrams are described (ptol = p-toluene sulfonate anion), together with the rheological properties of the gels determined as a function of the solvent, the gelator concentration as well as temperature. Microscopic observations of the gel structure are correlated to the composition and rheological properties of the gels. Magnetic and thermal studies show that both the gel-liquid and spin-crossover phenomena can be adjusted through the composition of the gel mixture.

  7. Removal properties of dissolved boron by glucomannan gel.

    Science.gov (United States)

    Oishi, Kyoko; Maehata, Yugo

    2013-04-01

    Boron ions have long been known to form complexes with the cis-diol group of a polysaccharide. Konjac glucomannan (KGM) which is one of polysaccharides was used to remove dissolved boron in this study. KGM forms a complex with boron, but does not remove boron from contaminated waters as well as other polysaccharides because of its high water solubility. Therefore, the removal efficiencies of dissolved boron were examined using both an insoluble KGM gel and KGM semi-gel. The former did not remove dissolved boron, but the latter did. The difference in the ability of boron removal was due to the presence of diol group inside. KGM loses free diol group during the process of gelation. On the other hand, the semi-gel gelated only surface layer in water has diol group inside. The boron removal capacity of the semi-gel was highest at pHs⩾11, when the boron species is present as B(OH)4(-). The capacity was slightly increased by the addition of Al, Ca and Mg under high pH conditions. This was due to co-precipitation of boron with Ca dissolved from the semi-gel. The boron adsorbed to the semi-gel easily was desorbed under low pH conditions and the hysteresis was not found. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Sol-gel Technology and Advanced Electrochemical Energy Storage Materials

    Science.gov (United States)

    Chu, Chung-tse; Zheng, Haixing

    1996-01-01

    Advanced materials play an important role in the development of electrochemical energy devices such as batteries, fuel cells, and electrochemical capacitors. The sol-gel process is a versatile solution for use in the fabrication of ceramic materials with tailored stoichiometry, microstructure, and properties. This processing technique is particularly useful in producing porous materials with high surface area and low density, two of the most desirable characteristics for electrode materials. In addition,the porous surface of gels can be modified chemically to create tailored surface properties, and inorganic/organic micro-composites can be prepared for improved material performance device fabrication. Applications of several sol-gel derived electrode materials in different energy storage devices are illustrated in this paper. V2O5 gels are shown to be a promising cathode material for solid state lithium batteries. Carbon aerogels, amorphous RuO2 gels and sol-gel derived hafnium compounds have been studied as electrode materials for high energy density and high power density electrochemical capacitors.

  9. The Synthesis of a Novel Cellulose Physical Gel

    Directory of Open Access Journals (Sweden)

    Jiufang Duan

    2014-01-01

    Full Text Available Cellulose possessing β-cyclodextrin (β-CD was used as a host molecule and cellulose possessing ferrocene (Fc as a guest polymer. Infrared spectra, differential scanning calorimetry (DSC, ultraviolet spectroscopy (UV, and contact angle analysis were used to characterise the material structure and the inclusion behaviour. The results showed that the β-CD-cellulose and the Fc-cellulose can form inclusion complexes. Moreover, ferrocene oxidation, and reduction of state can be adjusted by sodium hypochlorite (NaClO as an oxidant and glutathione (GSH as a reductant. In this study, a physical gel based on β-CD-cellulose/Fc-cellulose was formed under mild conditions in which autonomous healing between cut surfaces occurred after 24 hours. The physical gel can be controlled in the sol-gel transition. The compressive strength of the Fc-cellulose/β-CD-cellulose gel increased with increased cellulose concentration. The host-guest interaction between the side chains of cellulose could strengthen the gel. The cellulose physical gel may eventually be used as a stimulus-responsive, healing material in biomedical applications.

  10. Sol-gel-based biosensing applied to medicinal science.

    Science.gov (United States)

    Moreira, Felismina T C; Moreira-Tavares, Ana P; Sales, M Goreti F

    2015-01-01

    Biosensors have opened new horizons in biomedical analysis, by ensuring increased assay speed and flexibility, and allowing point-of-care applications, multi-target analyses, automation and reduced costs of testing. This has been a result of many studies merging nanotechnology with biochemistry over the years, thereby enabling the creation of more suitable environments to biological receptors and their substitution by synthetic analogue materials. Sol-gel chemistry, among other materials, is deeply involved in this process. Sol-gel processing allows the immobilization of organic molecules, biomacromolecules and cells maintaining their properties and activities, permitting their integration into different transduction devices, of electrochemical or optical nature, for single or multiple analyses. Sol-gel also allows to the production of synthetic materials mimicking the activity of natural receptors, while bringing advantages, mostly in terms of cost and stability. Moreover, the biocompatibility of sol-gel materials structures of biological nature allowed the use of these materials in emerging in vivo applications. In this chapter, biosensors for biomedical applications based on sol-gel derived composites are presented, compared and described, along with current emerging applications in vivo, concerning drug delivery or biomaterials. Sol-gel materials are shown as a promising tool for current, emerging and future medical applications.

  11. Comparative Skeletal Muscle Proteomics Using Two-Dimensional Gel Electrophoresis

    Science.gov (United States)

    Murphy, Sandra; Dowling, Paul; Ohlendieck, Kay

    2016-01-01

    The pioneering work by Patrick H. O’Farrell established two-dimensional gel electrophoresis as one of the most important high-resolution protein separation techniques of modern biochemistry (Journal of Biological Chemistry 1975, 250, 4007–4021). The application of two-dimensional gel electrophoresis has played a key role in the systematic identification and detailed characterization of the protein constituents of skeletal muscles. Protein changes during myogenesis, muscle maturation, fibre type specification, physiological muscle adaptations and natural muscle aging were studied in depth by the original O’Farrell method or slightly modified gel electrophoretic techniques. Over the last 40 years, the combined usage of isoelectric focusing in the first dimension and sodium dodecyl sulfate polyacrylamide slab gel electrophoresis in the second dimension has been successfully employed in several hundred published studies on gel-based skeletal muscle biochemistry. This review focuses on normal and physiologically challenged skeletal muscle tissues and outlines key findings from mass spectrometry-based muscle proteomics, which was instrumental in the identification of several thousand individual protein isoforms following gel electrophoretic separation. These muscle-associated protein species belong to the diverse group of regulatory and contractile proteins of the acto-myosin apparatus that forms the sarcomere, cytoskeletal proteins, metabolic enzymes and transporters, signaling proteins, ion-handling proteins, molecular chaperones and extracellular matrix proteins. PMID:28248237

  12. Formulation of a poly herbal gel for uterus flux

    Directory of Open Access Journals (Sweden)

    M. Rezghi

    2017-11-01

    Full Text Available Background and objectives: Over the centuries, herbal drugs have been used as major sources of medicine for the prevention and treatment of diseases. In recent years, there has been an exponential growth in the field of herbal medicines and these drugs are gaining popularity both in developing and developed countries because of their natural origin and less side effects. The present research has been undertaken to formulate and evaluate an herbal gel for uterus flux based on Iranian traditional medicine references. Methods: An aqueous extracts of fruit peels of Punica granatum and leaves of Myrtus communis, ethanol extract of oleo gum resins of Boswellia carterii and hydro-alcoholic extract of Carum carvi fruits were obtained. The gel was prepared by using the plants extract, carbopol 940, propylene glycol, tri-ethanolamine and distilled water. Further, the prepared gel was evaluated for physicochemical and microbial characteristics. Moreover, accelerated laboratory stability tests were performed. Results: The results showed good appearance and homogeneity of the gel. It was yellow-brown in color with acceptable physicochemical characteristics. Besides, the gel was stable towards physical changes and successfully passed microbiological tests. Conclusion: The prepared gel contained tannins which are astringent agents; therefore, this product could be an appropriate candidate for disorders like uterus flux with respect to its traditional use.

  13. Analysis of RNA by analytical polyacrylamide gel electrophoresis.

    Science.gov (United States)

    Petrov, Alexey; Tsa, Albet; Puglisi, Joseph D

    2013-01-01

    Polyacrylamide gel electrophoresis (PAGE) is a powerful tool for analyzing RNA samples. Denaturing PAGE provides information on the sample composition and structural integrity of the individual RNA species. Nondenaturing gel electrophoresis allows separation of the conformers and alternatively folded RNA species. It also can be used to resolve RNA protein complexes and to detect RNA complex formation by analyzing changes in the electrophoretic mobility of the RNA. RNA can be visualized within gels by different methods depending on the nature of the detection reagent. RNA molecules can be stained with various dyes, including toluidine blue, SYBR green, and ethidium bromide. Radioactively labeled RNA molecules are visualized by autoradiography, and fluorescently labeled RNA molecules can be observed with a fluorescence scanner. Generally, gels between 0.4 and 1.5mm thick are used for analytical PAGE. Gels thinner than 1mm are fragile and thus usually are not stained but rather are used for radiolabeled RNA. The gels are dried and the radiolabeled RNA is visualized by autoradiography. © 2013 Elsevier Inc. All rights reserved.

  14. Remineralizing Efficacy of Fluorohydroxyapatite Gel on Artificial Dentinal Caries Lesion

    Directory of Open Access Journals (Sweden)

    Qianqian Wang

    2015-01-01

    Full Text Available The aim was to evaluate the remineralizing efficacy of fluorohydroxyapatite (FHA gel on artificial dentinal caries lesion in vitro. Artificial carious lesions were made on occlusal cavities of teeth by exposing the dentin surface to a demineralizing solution. Each cavity was capped with a 3 mm thick FHA gel for 4 weeks. After the FHA gel was removed, the surface morphology and structure of the dentin were characterized by scanning electron microscopy (SEM, energy-dispersive X-ray spectroscopy (EDX, X-ray diffraction (XRD, and Fourier transform infrared spectroscopy (FT-IR. The dentin mineral density (DMD was measured by micro-computed tomography (Micro-CT. A layer of dense and orderly hexagonal crystal structure, with average diameter of 1 μm and thickness of 4~5 μm, could be observed on dentin surface. These crystals exhibited elemental peaks for calcium, phosphorus, carbon, and oxygen and characteristic peaks of hydroxyapatite (HA and fluorapatite (FA via XRD and FT-IR. The DMD of dentin surface layer significantly increased after it was capped with FHA gel (P<0.05. In the present study, the FHA gel could rapidly construct apatite on the artificial dentin caries surface and significantly increase the mineral density, which suggests that FHA gel might be a proper IPT material with remineralizing function.

  15. Lightweight, Soft Variable Stiffness Gel Spats for Walking Assistance

    Directory of Open Access Journals (Sweden)

    Yi Li

    2015-12-01

    Full Text Available With the rapid development of the aging society, many of the elderly people are in need of nursing care for their daily activities. Therefore, innovative technologies are needed to support the daily activities of elderly people and to lighten the heavy burden of nursing. We think the technology of soft actuators should be one of the key issues for developing such technologies. In this study, we focused on walking assistance for daily life and presented a preliminary work of developing novel poly vinyl chloride (PVC gel actuator-based lightweight and soft wearable assistive spats for supporting the walking motion of human. The PVC gel devices are incorporated in the generally used spats. The stiffness of the gel spats can be actively varied with the applied DC field turned on and off. The gel spats have the characteristics of a simple structure, a lightweight, easy to put on and take off, and with a high flexibility. A prototype was tested in the motions of lifting a foot and walking. It was found that the integrated electromyogram (IEMG and maximal voluntary contraction (%MVC values of the rectus femoris muscle reduced with the assistance of the gel spats, which demonstrated the potential of the gel spats as a device for walking assistance.

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

    Science.gov (United States)

    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.

  17. Dynamic Scaling of Colloidal Gel Formation at Intermediate Concentrations.

    Science.gov (United States)

    Zhang, Qingteng; Bahadur, Divya; Dufresne, Eric M; Grybos, Pawel; Kmon, Piotr; Leheny, Robert L; Maj, Piotr; Narayanan, Suresh; Szczygiel, Robert; Ramakrishnan, Subramanian; Sandy, Alec

    2017-10-27

    We have examined the formation and dissolution of gels composed of intermediate volume-fraction nanoparticles with temperature-dependent short-range attractions using small-angle x-ray scattering, x-ray photon correlation spectroscopy, and rheology to obtain nanoscale and macroscale sensitivity to structure and dynamics. Gel formation after temperature quenches to the vicinity of the rheologically determined gel temperature, T_{gel}, was characterized via the slowdown of dynamics and changes in microstructure observed in the intensity autocorrelation functions and structure factor, respectively, as a function of quench depth (ΔT=T_{quench}-T_{gel}), wave vector, and formation time t_{f}. We find the wave-vector-dependent dynamics, microstructure, and rheology at a particular ΔT and t_{f} map to those at other ΔTs and t_{f}s via an effective scaling temperature, T_{s}. A single T_{s} applies to a broad range of ΔT and t_{f} but does depend on the particle size. The rate of formation implied by the scaling is a far stronger function of ΔT than expected from the attraction strength between colloids. We interpret this strong temperature dependence in terms of cooperative bonding required to form stable gels via energetically favored, local structures.

  18. Gels de poly(octylthiophène) : cristallisation

    Science.gov (United States)

    Pépin-Donat, B.; Sixou, B.; de Geyer, A.; Viallat, A.; Fah. Hin, L. Won

    1998-06-01

    The study of conjugated poly(octylthiophene) gels by x-ray diffraction and differential calorimetry shows that these networks are semi-crystalline. State of crystallinity, transport properties and large scale heterogeneity seem to be correlated. The determination of this correlation requires a detailed study of the mechanisms of crystallization of these polymer gels, the first results of which are reported here. They show that crystallinity ratios and crystallization rates can be determined by NMR and, as expected, strongly depend on the gels thermodynamic history. L'étude de gels conjugués de poly(octylthiophène) par diffraction des rayons X et par calorimétrie différentielle montre que ces réseaux sont semi-cristallins. Etat de cristallinité, propriétés de transport et état d'hétérogénéité à grande échelle semblent être corrélés. La détermination de cette corrélation nécessite une étude approfondie des mécanismes de cristallisation de ces gels polymères dont les premiers résultats sont reportés ici. Ils montrent que taux de cristallinité et vitesses de cristallisation peuvent être déterminés par RMN et, comme attendu, dépendent fortement de l'histoire thermodynamique des gels.

  19. Development of lidocaine gels for enhanced local anesthetic action.

    Science.gov (United States)

    Shin, Sang-Chul; Cho, Cheong-Weon; Yang, Kyu-Ho

    2004-12-09

    In relieving local pains, lidocaine, one of ester type local anesthetics, has been used. To develop the lidocaine gels of enhanced local anesthetic effects, hydroxypropyl methylcellulose (HPMC) based bioadhesive polymer gel containing an enhancer was formulated. As the drug concentration in the gels increased up to 3%, the permeation rate of drug linearly increased, thereafter reaching a plateau. As the temperature of surrounding solutions increased, the permeation of drug increased. The activation energy of drug permeation was 3.29 kcal/mol for lidocaine. The permeation rate of drug through skin was studied using various enhancers, such as glycols, non-ionic surfactants, and bile salts. Among the enhancers studied, diethylene glycol showed the greatest enhancing effects on drug permeation through skin. The analgesic activity was examined using a tail-flick analgesimeter. In the area under the efficacy curve (AUEC) of the rat-tail flick tests, lidocaine gel containing diethylene glycol showed about 3.89-fold increase in analgesic activity compared with the control. The addition of vasoconstrictor in the gels prolonged the analgesic effects. The result of this study supports that the bioadhesive gel with efficient anesthetic effect could be developed using HPMC with combination of enhancer and vasoconstrictor.

  20. High lane density slab-gel electrophoresis using micromachined instrumentation.

    Science.gov (United States)

    Papautsky, I; Mohanty, S; Weiss, R; Frazier, A B

    2001-10-01

    In this paper, micromachined pipette arrays (MPAs) and microcombs were studied as a means of enabling high lane density gel electrophoresis. The MPA provide a miniaturized format to interface sub-microliter volumes of samples between macroscale sample preparation formats and microscale biochemical analysis systems. The microcombs provide a means of creating sample loading wells in the gel material on the same center-to-center spacing as the MPAs. Together, the two micromachined instruments provide an alternative to current combs and pipetting technologies used for creating sample loading wells and sample delivery in gel electrophoresis systems. Using three designs for the microcomb-MPA pair, center-to-center spacings of 1.0 mm, 500 microm, and 250 microm are studied. The results demonstrate an approximate 10-fold increase in lane density and a 10-fold reduction in sample size from 5 microL to 500 pL. As a result, the number of theoretical plates has increased 2.5-fold, while system resolution has increased 1.5-fold over the conventional agarose gel systems. An examination of changes in resolution across the width of individual separation lanes in both systems revealed dependence in the case of the conventional gels and no dependence for the gels loaded with the micromachined instrumentation.

  1. Preparative two-dimensional gel electrophoresis with agarose gels in the first dimension for high molecular mass proteins.

    Science.gov (United States)

    Oh-Ishi, M; Satoh, M; Maeda, T

    2000-05-01

    A two-dimensional gel electrophoresis (2-DE) method that uses an agarose isoelectric focusing (IEF) gel in the first dimension (agarose 2-DE) was compared with an immobilized pH gradient 2-DE method (IPG-Dalt). The former method was shown to produce significant improvements in the 2-D electrophoretic separation of high molecular mass proteins larger than 150 kDa, up to 500 kDa, and to have a higher loading capacity, as much as 1.5 mg proteins in total for micropreparative runs. The extraction medium found best in this study for agarose 2-DE of mammal tissues was 6 M urea, 1 M thiourea, 0.5% 2-mercaptoethanol, protease inhibitor cocktail (Complete Mini EDTA-free), 1% Triton X-100 and 3% 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS). Trichloroacetic acid (TCA) treatment of the agarose gel after IEF is to be carefully weighed beforehand, because some high molecular mass proteins were less likely to enter the second-dimensional polyacrylamide gel after TCA fixation, and proteins such as mouse skeletal muscle actin gave pseudospots in the agarose 2-DE patterns without TCA fixation. As a good compromise we suggest fixation of proteins in the agarose gel with TCA for one hour or less. The first-dimensional agarose IEF gel containing Pharmalyte as a carrier ampholyte was 180 mm in length and 2.5-4.8 mm in diameter. The gel diameter was shown to determine the loading capacity of the agarose 2-DE, and 1.5 mg liver proteins in total were successfully separated by the use of a 4.8 mm diameter agarose gel.

  2. Fabrication and Optimization of a PAGATA Gel Dosimeter: Increasing the Melting Point of the PAGAT Gel Dosimeter with Agarose Additive

    Directory of Open Access Journals (Sweden)

    Bakhtiar Azadbakht

    2010-12-01

    Full Text Available Introduction: The PAGAT polymer gel dosimeter melts at 30 ˚C and even at room temperature during the summer, so it needs to be kept in a cool place such as a refrigerator. To increase the stability of the PAGAT gel, different amounts of agarose were added to the PAGAT gel composition and the PAGATA gel was manufactured. Material and Methods: The PAGATA gel vials were irradiated using a Co-60 machine. Then, the samples were evaluated using a 1.5 T Siemens MRI scanner. The ingredients of the PAGATA normoxic gel dosimeter were 4.5% N-N' methylen-bis-acrylamide, 4.5% acrylamide, 4.5% gelatine, 5 mM tetrakis (THPC, 0.01 mM hydroquinone (HQ, 0.5% agarose and 86% de-ionized water (HPLC. Results: Melting point and sensitivity of the PAGAT gel dosimeter with addition of 0.0, 0.3, 0.5, 1.0, 1.5 and 2.0% of agarose were measured, in which the melting points were increased to 30, 82, 86, 88, 89 and 90°C and their sensitivities found to be 0.113, 0.1059, 0.125, 0.122, 0.115 and 0.2  respectively. Discussion and Conclusions: Adding agarose increased the sensitivity and background R2 of the evaluated samples. The optimum amount of agarose was found to be 0.5% regarding these parameters and also the melting point of the gel dosimeter. A value of 0.5% agarose was found to be an optimum value considering the increase of sensitivity to 0.125 and melting point to 86°C but at the expense of increasing the background R2 to 4.530.

  3. Study of gel grown mixed crystals of Bax (IO3 )4

    Indian Academy of Sciences (India)

    Administrator

    Mixed iodate crystals of barium calcium iodate are used in medicine and production of other iodates. The purpose of the present paper is to report the growth and influence of various parameters such as pH of gel, gel reactants, gel concentrations, effect of neutral gel etc on the growth mechanism of mixed iodate crystals of.

  4. Growth and study of some gel grown group II single crystals of iodate

    Indian Academy of Sciences (India)

    Unknown

    Page 1 ... Abstract. Single crystals of calcium iodate and barium iodate were grown by simple gel technique by single diffusion method. The optimum conditions were established by varying various parameters such as pH of gel solution, gel concentration, gel setting time, concentration of the reactants etc. Crystals having ...

  5. Study of gel grown mixed crystals of Bax Ca ((IO3) 4

    Indian Academy of Sciences (India)

    The growth of mixed crystals of BaCa1–(IO3)4 were carried out with simple gel method. The effect of various parameters such as pH of gel solution, gel concentration, gel setting time, concentration of reactants on the growth was studied. Crystals having different morphologies and habits were obtained. The grown ...

  6. Modification of gel architecture and TBE/TAE buffer composition to minimize heating during agarose gel electrophoresis.

    Science.gov (United States)

    Sanderson, Brian A; Araki, Naoko; Lilley, Jennifer L; Guerrero, Gilberto; Lewis, L Kevin

    2014-06-01

    Agarose gel electrophoresis of DNA and RNA is routinely performed using buffers containing either Tris, acetate, and EDTA (TAE) or Tris, borate, and EDTA (TBE). Gels are run at a low, constant voltage (∼10 V/cm) to minimize current and asymmetric heating effects, which can induce band artifacts and poor resolution. In this study, alterations of gel structure and conductive media composition were analyzed to identify factors causing higher electrical currents during horizontal slab gel electrophoresis. Current was reduced when thinner gels and smaller chamber buffer volumes were used, but was not influenced by agarose concentration or the presence of ethidium bromide. Current was strongly dependent on the amount and type of EDTA used and on the concentrations of the major acid-base components of each buffer. Interestingly, resolution and the mobilities of circular versus linear plasmid DNAs were also affected by the chemical form and amount of EDTA. With appropriate modifications to gel structure and buffer constituents, electrophoresis could be performed at high voltages (20-25 V/cm), reducing run times by up to 3-fold. The most striking improvements were observed with small DNAs and RNAs (10-100 bp): high voltages and short run times produced sharper bands and higher resolution. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Agar/gelatin bilayer gel matrix fabricated by simple thermo-responsive sol-gel transition method.

    Science.gov (United States)

    Wang, Yifeng; Dong, Meng; Guo, Mengmeng; Wang, Xia; Zhou, Jing; Lei, Jian; Guo, Chuanhang; Qin, Chaoran

    2017-08-01

    We present a simple and environmentally-friendly method to generate an agar/gelatin bilayer gel matrix for further biomedical applications. In this method, the thermally responsive sol-gel transitions of agar and gelatin combined with the different transition temperatures are exquisitely employed to fabricate the agar/gelatin bilayer gel matrix and achieve separate loading for various materials (e.g., drugs, fluorescent materials, and nanoparticles). Importantly, the resulting bilayer gel matrix provides two different biopolymer environments (a polysaccharide environment vs a protein environment) with a well-defined border, which allows the loaded materials in different layers to retain their original properties (e.g., magnetism and fluorescence) and reduce mutual interference. In addition, the loaded materials in the bilayer gel matrix exhibit an interesting release behavior under the control of thermal stimuli. Consequently, the resulting agar/gelatin bilayer gel matrix is a promising candidate for biomedical applications in drug delivery, controlled release, fluorescence labeling, and bio-imaging. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Dynamical transition of heat transport in a physical gel near the sol-gel transition

    Science.gov (United States)

    Kobayashi, Kazuya U.; Oikawa, Noriko; Kurita, Rei

    2015-12-01

    We experimentally study heat transport in a gelatin solution near a reversible sol-gel transition point where viscosity strongly depends on temperature. We visualize the temperature field and velocity field using thermochromic liquid crystals and polystyrene latex particles, respectively. During the initial stages of heating, we find that heat transport undergoes a dynamical transition from conductive to convective. Subsequently, during later stages, we observe that the transport dynamics are much more complex than conventional thermal convections. At the sample’s surface we observe the formation of stagnant domains, which lack fluid flow. Their formation is not due to the effects of local cooling. We determine that it is the dynamics of these stagnant domains that induce convective-conductive-convective transitions.

  9. Slow Release of Plant Volatiles Using Sol-Gel Dispensers.

    Science.gov (United States)

    Bian, L; Sun, X L; Cai, X M; Chen, Z M

    2014-12-01

    The black citrus aphid, also known as the tea aphid, (Toxoptera aurantii Boyer) attacks economically important crops, including tea (Camellia sinensis (L.) O. Kuntze). In the current study, silica sol-gel formulations were screened to find one that could carry and release C. sinensis plant volatiles to lure black citrus aphids in a greenhouse. The common plant volatile trans-2-hexen-1-al was used as a model molecule to screen for suitable sol-gel formulations. A zNose (Electronic Sensor Technology, Newbury Park, CA) transportable gas chromatograph was used to continuously monitor the volatile emissions. A sol-gel formulation containing tetramethyl orthosilicate and methyltrimethoxysilane in an 8:2 (vol:vol) ratio was selected to develop a slow-release dispenser. The half-life of trans-2-hexen-1-al in the sol-gel dispenser increased slightly with the volume of this compound in the dispenser. Ten different volatiles were tested in the sol-gel dispenser. Alcohols of 6-10 carbons had the longest half-lives (3.01-3.77 d), while esters of 6-12 carbons had the shortest (1.53-2.28 d). Release of these volatiles from the dispensers could not be detected by the zNose after 16 d (cis-3-hexenyl acetate) to 26 d (3,7-dimethylocta-1,6-dien-3-ol). In greenhouse experiments, trans-2-hexen-1-al and cis-3-hexen-1-ol released from the sol-gel dispensers attracted aphids for ≍17 d, and release of these volatiles could not be detected by the zNose after ≍24 d. The sol-gel dispensers performed adequately for the slow release of plant volatiles to trap aphids in the greenhouse. © 2014 Entomological Society of America.

  10. Modelling the behaviour of the push-pull gel dosimeter

    International Nuclear Information System (INIS)

    Bosi, S.G.; Davies, J.B.; Gorjiara, T.; Baldock, C.

    2010-01-01

    Full text: Recent development of a gel dosimeter based on the radiobleaching pigment, genipin, allows development of a new 3D optically scanned gel dosimeter-the p ush-pull g el. This gel would contain two spectrally complementary pigments, one which darkens with dose and another (e.g. genipin) which bleaches. The two pigments deal separately with the high and low dose ends of the dosimeter's dynamic range. The bleaching pigment would be optimised for high sensitivity and the darkening pigment for low. Employing dual pigments, optimised independently, relaxes the need for compromise between sensitivity at low dose and accuracy at high dose. Such a gel, after exposure, would be read using two successive optical CT scans, at two different wavelengths. The reduction in sensitivity of the darkening pigment (allowed by the use of push-pull) would reduce the occurrence of regions of high optical attenuation which can generate optical CT artefacts. Simulated optical CT reconstructions of the optical density map (Fig. La) scanned at the darkening pigment wavelength of a hypothetical push-pull gel, confirms the reduction in susceptibility to artefacts. Fig. I b shows a profile through the map with no stray light added. The centre of the profile in Fig. I d shows a cupping artefact produced by 10 ppm of stray light. The similarity of Fig. Ic and b show that a 30% sensitivity reduction allowed by push-pull, renders the artefact negligible. This paper presents the results of' these simulations of a push-pull gel scanned using optical CT and also some results of experiments with genipin gel. (author)

  11. To gel or not to gel: correlating molecular gelation with solvent parameters.

    Science.gov (United States)

    Lan, Y; Corradini, M G; Weiss, R G; Raghavan, S R; Rogers, M A

    2015-10-07

    Rational design of small molecular gelators is an elusive and herculean task, despite the rapidly growing body of literature devoted to such gels over the past decade. The process of self-assembly, in molecular gels, is intricate and must balance parameters influencing solubility and those contrasting forces that govern epitaxial growth into axially symmetric elongated aggregates. Although the gelator-gelator interactions are of paramount importance in understanding gelation, the solvent-gelator specific (i.e., H-bonding) and nonspecific (dipole-dipole, dipole-induced and instantaneous dipole induced forces) intermolecular interactions are equally important. Solvent properties mediate the self-assembly of molecular gelators into their self-assembled fibrillar networks. Herein, solubility parameters of solvents, ranging from partition coefficients (log P), to Henry's law constants (HLC), to solvatochromic parameters (ET(30)), and Kamlet-Taft parameters (β, α and π), and to Hansen solubility parameters (δp, δd, δh), are correlated with the gelation ability of numerous classes of molecular gelators. Advanced solvent clustering techniques have led to the development of a priori tools that can identify the solvents that will be gelled and not gelled by molecular gelators. These tools will greatly aid in the development of novel gelators without solely relying on serendipitous discoveries. These tools illustrate that the quest for the universal gelator should be left in the hands of Don Quixote and as researchers we must focus on identifying gelators capable of gelling classes of solvents as there is likely no one gelator capable of gelling all solvents.

  12. Structural studies of gels and gel-glasses in the SiO2-GeO2 system using vibrational spectroscopy

    Science.gov (United States)

    Mukherjee, Shyama P.; Sharma, Shiv K.

    1986-01-01

    GeO2 gel and gels in the SiO2-GeO2 system synthesized by the hydrolytic polycondensation of metal alkoxides have been studied by infrared and Raman spectroscopic techniques. The molecular structures, hydroxyl contents, and crystallinity of gels and gel-glasses in relation to the thermal history and GeO2 concentration were investigated. The binary compositions having up to 70 mol percent GeO2 were examined.

  13. Conformational changes of a single magnetic particle string within gels.

    Science.gov (United States)

    An, Hai-Ning; Groenewold, Jan; Picken, S J; Mendes, Eduardo

    2014-02-21

    Magnetorheological (MR) gels consist of micron sized magnetic particles inside a gel matrix. Before physical cross-linking, the suspension is subjected to a small magnetic field which creates a particle string structure. After cross-linking, the string is kept within the gel at room temperature. Under an external homogeneous magnetic field and mechanical deformation, the soft swollen gel matrix allows the string to largely rearrange at microscopic scales. With the help of two homemade magneto cells mounted on an optical microscope, we were able to follow the conformational change and instabilities of a single magnetic particle string under the combined influence of shear (or stretch) and the magnetic field. In the absence of mechanical deformation, an external magnetic field, applied in the perpendicular direction to the string, breaks it into small pieces generating periodic structures like sawteeth. When an external magnetic field is applied parallel to the pre-aligned string, it exhibits a length contraction. However, under shear strain perpendicular to the original pre-structured string (and magnetic field), the string breaks and short string segments tilt, making an angle with the original direction that is smaller than that of the applied shear (non-affine). The difference in tilt angle scales with the inverse length of the small segments L-1 and the magnetic flux density B, reflecting the ability of the gel matrix to expel solvents under local stress.

  14. Comparative gel-based phosphoproteomics in response to signaling molecules

    KAUST Repository

    Marondedze, Claudius

    2013-09-03

    The gel-based proteomics approach is a valuable technique for studying the characteristics of proteins. This technique has diverse applications ranging from analysis of a single protein to the study of the total cellular proteins. Further, protein quality and to some extent distribution can be first assessed by means of one-dimensional gel electrophoresis and then more informatively, for comparative analysis, using the two-dimensional gel electrophoresis technique. Here, we describe how to take advantage of the availability of fluorescent dyes to stain for a selective class of proteins on the same gel for the detection of both phospho- and total proteomes. This enables the co-detection of phosphoproteins as well as total proteins from the same gel and is accomplished by utilizing two different fluorescent stains, the ProQ-Diamond, which stains only phosphorylated proteins, and Sypro Ruby, which stains the entire subset of proteins. This workflow can be applied to gain insights into the regulatory mechanisms induced by signaling molecules such as cyclic nucleotides through the quantification and subsequent identification of responsive phospho- and total proteins. © Springer Science+Business Media New York 2013.

  15. Hydrophobicity of hemp shiv treated with sol-gel coatings

    Science.gov (United States)

    Hussain, Atif; Calabria-Holley, Juliana; Schorr, Diane; Jiang, Yunhong; Lawrence, Mike; Blanchet, Pierre

    2018-03-01

    This is the first time sol-gel technology is used in the treatment of hemp shiv to develop sustainable thermal insulation building materials. The impact on the hydrophobicity of hemp shiv by depositing functionalised sol-gel coatings using hexadecyltrimethoxysilane (HDTMS) has been investigated. Bio-based materials have tendency to absorb large amounts of water due to their hydrophilic nature and highly porous structure. In this work, the influence of catalysts, solvent dilution and HDTMS loading in the silica sols on the hydrophobicity of hemp shiv surface has been reported. The hydrophobicity of sol-gel coated hemp shiv increased significantly when using acid catalysed sols which provided water contact angles of up to 118° at 1% HDTMS loading. Ethanol diluted sol-gel coatings enhanced the surface roughness of the hemp shiv by 36% as observed under 3D optical profilometer. The XPS results revealed that the surface chemical composition of the hemp shiv was altered by the sol-gel coating, blocking the hydroxyl sites responsible for hydrophilicity.

  16. Structural Evolution and Stability of Sol-Gel Biocatalysts

    International Nuclear Information System (INIS)

    Rodgers, L.E.; Foster, L.J.R.; Holden, P.J.; Knott, R.B.; Bartlett, J.B.

    2005-01-01

    Full text: Immobilisation strategies for catalytic enzymes are important as they allow reuse of the biocatalysts. Sol-gel materials have been used to immobilise Candida antarctica lipase B (CALB), a commonly used industrial enzyme with a known crystal structure. The sol-gel bioencapsulate is produced through the condensation of suitable metal alkoxides in the presence of CALB, yielding materials with controlled pore sizes, volume and surface chemistry. Sol-gel matrices have been shown to prolong the catalytic life and enhance the activity of CALB, although the molecular basis for this effect has yet to be elucidated due to the limitations of analysis techniques applied to date. Small angle neutron scattering (SANS) allows such multicomponent systems to be characterised through contrast matching. In the sol-gel bioencapsulate system, at the contrast match point for silica, residual scattering intensity is due to the CALB and density fluctuations in the matrix. A SANS contrast variation series found the match point for the silica matrix, both with and without enzyme present, to be around 35 percent. The model presented here proposes a mechanism for the interaction between CALB and the surrounding sol-gel matrix, and the observed improvement in enzyme activity and matrix strength. The SANS protocol developed here may be applied more generally to bioencapsulates. (authors)

  17. Laser-induced transfer of gel microdroplets for cell printing

    Science.gov (United States)

    Yusupov, V. I.; Zhigar'kov, V. S.; Churbanova, E. S.; Chutko, E. A.; Evlashin, S. A.; Gorlenko, M. V.; Cheptsov, V. S.; Minaev, N. V.; Bagratashvili, V. N.

    2017-12-01

    We study thermal and transport processes involved in the transfer of gel microdroplets under the conditions of laser cell microprinting. The specific features of the interaction of pulsed laser radiation ( λ = 1.064 µm, pulse duration 4 - 200 ns, energy 2 µJ - 1 mJ) with the absorbing gold film deposited on the glass donor substrate are determined. The investigation of the dynamics of transport processes by means of fast optical video recording and optoacoustic methods makes it possible to determine the characteristics of the produced gel jets as functions of the laser operation regimes. The hydrodynamic process of interaction between the laser radiation and the gold coating with the hydrogel layer on it is considered and the temperature in the region of the laser pulse action is estimated. It is shown that in the mechanism of laser-induced transfer a significant role is played by the processes of explosive boiling of water (in gel) and gold. The amount of gold nanoparticles arriving at the acceptor plate in the process of the laser transfer is determined. For the laser pulse duration 8 ns and small energies (less than 10 µJ), the fraction of gold nanoparticles in the gel microdroplets is negligibly small, and their quantity linearly grows with increasing pulse energy. The performed studies offer a base for optimising the processes of laser transfer of gel microdroplets in the rapidly developing technologies of cell microprinting.

  18. Dapsone 7.5% Gel: A Review in Acne Vulgaris.

    Science.gov (United States)

    Al-Salama, Zaina T; Deeks, Emma D

    2017-02-01

    Dapsone 7.5% gel (Aczone ® ) is indicated for the once-daily topical treatment of acne vulgaris in patients aged ≥12 years. Dapsone is a sulfone antibacterial with anti-inflammatory actions, which are thought to be largely responsible for its efficacy in treating acne vulgaris. In two phase III trials of 12 weeks' duration in patients aged ≥12 years with moderate acne vulgaris, once-daily dapsone 7.5% gel reduced acne severity (as per the Global Acne Assessment Score) and lesion counts versus vehicle. The benefits of dapsone 7.5% gel over vehicle were seen as early as week 2 for inflammatory lesion counts, and from week 4 or 8 for other outcomes. Dapsone 7.5% gel was well tolerated, with a low incidence of treatment-related adverse events, with the majority of adverse events being administration-site related and mild or moderate in severity. Thus, dapsone 7.5% gel is an effective and well tolerated option for the topical treatment of acne vulgaris in patients aged ≥12 years, with the convenience of once-daily application.

  19. Detection of ultraviolet radiation using tissue equivalent radiochromic gel materials

    International Nuclear Information System (INIS)

    Bero, M A; Abukassem, I

    2009-01-01

    Ferrous Xylenol-orange Gelatin gel (FXG) is known to be sensitive to ionising radiation such as γ and X-rays. The effect of ionising radiation is to produce an increase in the absorption over a wide region of the visible spectrum, which is proportional to the absorbed dose. This study demonstrates that FXG gel is sensitive to ultraviolet radiation and therefore it could functions as UV detector. Short exposure to UV radiation produces linear increase in absorption measured at 550nm, however high doses of UV cause the ion indicator colour to fad away in a manner proportional to the incident UV energy. Light absorbance increase at the rate of 1.1% per minute of irradiation was monitored. The exposure level at which the detector has linear response is comparable to the natural summer UV radiation. Evaluating the UV ability to pass through tissue equivalent gel materials shows that most of the UV gets absorbed in the first 5mm of the gel materials, which demonstrate the damaging effects of this radiation type on human skin and eyes. It was concluded that FXG gel dosimeter has the potential to offer a simple, passive ultraviolet radiation detector with sensitivity suitable to measure and visualises the natural sunlight UV exposure directly by watching the materials colour changes.

  20. Nonmonotonic DNA-length-dependent mobility in pluronic gels

    Science.gov (United States)

    You, Seungyong; Wei, Ling; Shanbhag, Sachin; Van Winkle, David H.

    2017-04-01

    Two-dimensional electrophoresis was used to analyze the mobility of DNA fragments in micellar gels of pluronic F127 (E O100P O70E O100 ) and pluronic P123 (E O20P O70E O20 ) . The 20-3500 base pair DNA fragments were separated by size first in agarose gels, and then in pluronic gels at room temperature. In agarose gels, the DNA mobility decreases monotonically with increasing DNA length. In pluronic gels, however, the mobility varies nonmonotonically according to fragment lengths that are strongly correlated with the diameter of the spherical micelles. Brownian dynamics (BD) simulations with short-ranged intra-DNA hydrodynamic interactions were performed to numerically calculate the length-dependent mobility in pluronic lattices. The rising and falling trends, as well as the oscillations of mobility, were captured by the coarse-grained BD simulations. Molecular dynamics simulations in pluronic F127, with explicitly modeled micelle coronas, justified that the hydrodynamic interactions mediated by the complex fluid of hydrated poly(ethylene oxide) are a possible reason for the initial rise of mobility with DNA length.

  1. Nanoparticles laden in situ gel for sustained ocular drug delivery

    Directory of Open Access Journals (Sweden)

    Himanshu Gupta

    2013-01-01

    Full Text Available Proper availability of drug on to corneal surface is a challenging task. However, due to ocular physiological barriers, conventional eye drops display poor ocular bioavailability of drugs (< 1%. To improve precorneal residence time and ocular penetration, earlier our group developed and evaluated in situ gel and nanoparticles for ocular delivery. In interest to evaluate the combined effect of in situ gel and nanoparticles on ocular retention, we combined them. We are the first to term this combination as "nanoparticle laden in situ gel", that is, poly lactic co glycolic acid nanoparticle incorporated in chitosan in situ gel for sparfloxacin ophthalmic delivery. The formulation was tested for various physicochemical properties. It showed gelation pH near pH 7.2. The observation of acquired gamma camera images showed good retention over the entire precorneal area for sparfloxacin nanoparticle laden in situ gel (SNG as compared to marketed formulation. SNG formulation cleared at a very slow rate and remained at corneal surface for longer duration as no radioactivity was observed in systemic circulation. The developed formulation was found to be better in combination and can go up to the clinical evaluation and application.

  2. Effects of fibre dimension and charge density on nanocellulose gels.

    Science.gov (United States)

    Mendoza, Llyza; Gunawardhana, Thilina; Batchelor, Warren; Garnier, Gil

    2018-04-18

    Carboxylated cellulose nanofibres can produce gels at low concentrations. The effect of pulp source on the nanocellulose fibre dimension and gel rheology are studied. It is hypothesised that fibre length and surface charge influence aspects of the gel rheological properties. TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl)- mediated oxidised cellulose nanofibres from never-dried hardwood and softwood pulp and containing different charge levels were produced and characterized. Steady-state and dynamic rheological studies were performed to ascertain the effects of pulp type on gel behavior and properties. Nanocellulose fibres extracted from softwood (SW-TOCN) and hardwood (HW-TOCN) pulp exhibit similar widths but different length dimensions as shown via AFM analysis. Rheological measurements show that the dynamic moduli (G' and G'') of nanocellulose gels are independent of pulp source and are mostly influenced by fibre concentration. Differences in the steady-state behavior (i.e. viscosity) at constant surface charge can be attributed to differences in fibre length. Increasing the surface charge density influences the critical strain and the viscosity at the percolation concentration (0.1 wt%) due to higher electrostatic interactions. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

  3. Modeling active materials based on self-oscillating gels

    Science.gov (United States)

    Yashin, Victor V.; Balazs, Anna C.

    2011-03-01

    The Belousov-Zhabotinsky (BZ) reaction in solution is a classical example of an active medium that demonstrates various chemical oscillations and waves, which can be observed visually. Grafting a ruthenium metal-ion complex, the catalyst to the BZ reaction, to a chemo-responsive polymer gel creates an active material (BZ gel), which exhibits periodic volumetric changes in the course of the reaction. The redox oscillations of the catalyst affect the polymer-solvent interactions and cause the periodic swelling and de-swelling of the gel, so that chemo- mechanical energy transduction occurs within the material. We consider a model that couples the polymer gel dynamics and the BZ reaction kinetics; the latter is described by the modified Oregonator model. The model equations are solved numerically in 2D. We demonstrate that the dynamical behavior of the BZ gel can be controlled by a heterogeneous distribution of the catalyst and by such structural features as the solvent-filled voids. The dynamics of an active membrane having the self-oscillating pores is considered as an example.

  4. Self-Supporting Nanodiamond Gels: Elucidating Colloidal Interactions Through Rheology_

    Science.gov (United States)

    Adhikari, Prajesh; Tripathi, Anurodh; Vogel, Nancy A.; Rojas, Orlando J.; Raghavan, Sriunivasa R.; Khan, Saad A.

    This work investigates the colloidal interactions and rheological behavior of nanodiamond (ND) dispersions. While ND represents a promising class of nanofiller due to its high surface area, superior mechanical strength, tailorable surface functionality and biocompatibility, much remains unknown about the behavior of ND dispersions. We hypothesize that controlling interactions in ND dispersions will lead to highly functional systems with tunable modulus and shear response. Steady and dynamic rheology techniques are thus employed to systematically investigate nanodiamonds dispersed in model polar and non-polar media. We find that low concentrations of ND form gels almost instantaneously in a non-polar media. In contrast, ND's in polar media show a time-dependent behavior with the modulus increasing with time. We attribute the difference in behavior to variations in inter-particle interactions as well as the interaction of the ND with the media. Large steady and oscillatory strains are applied to ND colloidal gels to investigate the role of shear in gel microstructure breakdown and recovery. For colloidal gels in non-polar medium, the incomplete recovery of elastic modulus at high strain amplitudes indicates dominance of particle-particle interactions; however, in polar media the complete recovery of elastic modulus even at high strain amplitudes indicates dominance of particle-solvent interactions. These results taken together provide a platform to develop self-supporting gels with tunable properties in terms of ND concentration, and solvent type.

  5. Preparation of silica by sol-gel method using formamide

    Directory of Open Access Journals (Sweden)

    R.F.S. Lenza

    2001-07-01

    Full Text Available In this work we obtained microporous and mesoporous silica gels by sol-gel processing. Tetraethylortosilicate (TEOS was used as precursor. Nitric acid and hydrofluoric acid were used as catalysts. In order to study the affect of formamide as drying additive, we used a molar ratio alkoxide/formamide of 1/1. The performance of formamide in obtaining crack-free gels was evaluated through monolithicity measurements. The structural evolution occurring in the interconnected network of the gels during thermal treatment was monitored by Fourier transform infrared spectroscopy (FTIR, shrinkage and density measurements and nitrogen gas sorption. We noted that in the presence of formamide, the Si-O-Si bonds are stronger and belong to a more cross-linked structure. The samples obtained in the presence of formamide have larger pore volume and its pore structure is in the range of mesoporosity. The samples obtained without additive are microporous. Formamide allowed the preparation of crack-free silica gels stabilized at high temperatures.

  6. Pulsed-field gel electrophoresis of bacterial chromosomes.

    Science.gov (United States)

    Mawer, Julia S P; Leach, David R F

    2013-01-01

    The separation of fragments of DNA by agarose gel electrophoresis is integral to laboratory life. Nevertheless, standard agarose gel electrophoresis cannot resolve fragments bigger than 50 kb. Pulsed-field gel electrophoresis is a technique that has been developed to overcome the limitations of standard agarose gel electrophoresis. Entire linear eukaryotic chromosomes, or large fragments of a chromosome that have been generated by the action of rare-cutting restriction endonucleases, can be separated using this technique. As a result, pulsed-field gel electrophoresis has many applications, from karyotype analysis of microbial genomes, to the analysis of chromosomal strand breaks and their repair intermediates, to the study of DNA replication and the identification of origins of replication. This chapter presents a detailed protocol for the preparation of Escherichia coli chromosomal DNA that has been embedded in agarose plugs, digested with the rare-cutting endonuclease NotI, and separated by contour-clamped homogeneous field electrophoresis. The principles in this protocol can be applied to the separation of all fragments of DNA whose size range is between 40 kb and 1 Mb.

  7. Efficacy and safety of once-daily metronidazole 1% gel compared with twice-daily azelaic acid 15% gel in the treatment of rosacea.

    Science.gov (United States)

    Wolf, John E; Kerrouche, Nabil; Arsonnaud, Stephanie

    2006-04-01

    Rosacea is an inflammatory dermatologic disorder characterized by the presence of facial erythema, visible blood vessels, papules, and pustules. The National Rosacea Society has established a classification system that identifies 4 distinct rosacea subtypes based on clinical presentation: erythematotelangiectatic, papulopustular, phymatous, and ocular. The goal of topical therapy for rosacea is to reduce inflammatory lesion counts; decrease intensity of erythema; and reduce symptoms such as stinging, burning, and pruritus. Metronidazole and azelaic acid are thought to reduce the inflammation associated with rosacea by inhibiting the production of reactive oxygen species produced by neutrophils. Both metronidazole 1% gel and azelaic acid 15% gel recently have been approved for the treatment of rosacea. The current study was conducted to compare the once-daily application of metronidazole 1% gel with twice-daily applications of azelaic acid 15% gel for the treatment of patients with moderate rosacea (N=160). Both treatments showed similar reductions in inflammatory lesion counts (77% for metronidazole 1% gel and 80% for azelaic acid 15% gel) and high success rates in both global severity (53.7% vs 56.4% for metronidazole 1% gel and azelaic acid 15% gel, respectively) and erythema (42.7% vs 42.3% for metronidazole 1% gel and azelaic acid 15% gel, respectively). On average, the efficacy (including reduction in erythema) of the once-daily application of metronidazole 1% gel and twice-daily applications of azelaic acid 15% gel were similar.

  8. Application of phase diagrams to obtain a new surfactant-based fracturing gel; Aplicacao de diagrama de fases para obtencao de um novo gel de fraturamento hidraulico

    Energy Technology Data Exchange (ETDEWEB)

    Dantas, Tereza N. de Castro; Santana, Vanessa C.; Dantas Neto, Afonso A.; Franca Neta, Luzia S. de; Albuquerque, Heraldo S. [Rio Grande do Norte Univ., Natal, RN (Brazil)]. E-mail: tereza@eq.ufrn.br

    2003-07-01

    Through pseudo ternary phases diagram was defined a gel area with the objective of obtaining a new surfactant-based fracturing gel. The surfactant used was synthesized from regional vegetable oil. Fracturing gel properties, like: viscosity, leak off coefficient and proppant-settling rate were analyzed. The obtained results with the surfactant-based gel had its properties compared with a HPG-based gel (hydroxypropyl guar). Rheological tests was accomplished at 100 s{sup -1} being varied the temperature from 26 to 86 deg C, where the surfactant-based gel showed great results. The leak off coefficient was determined by static filtration and the new gel presented smaller coefficient in relation to the HPG gel. The proppant-setting rate was also determined in the gel and, the surfactant-based gel showed good static proppant support. One can conclude that obtained gel presents compatible characteristics when compared with the HPG gel, without the inconvenience of leaving insoluble residues in the well. (author)

  9. [Tranexamic acid gel in patients treated with oral anticoagulants].

    Science.gov (United States)

    Ripollés-de Ramón, Jorge; Muñoz-Corcuera, Marta; Bravo-Llatas, Carmen; Bascones-Martínez, Antonio

    2014-12-09

    Patients treated with oral anticoagulants have increased susceptibility to bleeding, and therefore any surgical medical procedure and especially oral surgery requires a therapeutic approach that minimizes bleeding effects in these patients. The working hypothesis was based on studies of local application of tranexamic acid after maxillofacial interventions as effective therapeutic alternative for the prevention and control of bleeding. The aim was to assess the effectiveness of the application of a gel solution tranexamic acid after tooth extraction in anticoagulated patients in terms of healing time and degree of healing. The results indicate that application of tranexamic acid gel is very effective for consistency and maintenance in the place of action and shows its efficacy as a procoagulant material. The application of a gel solution of tranexamic acid in oral anticoagulants patients ameliorates healing time and the bleeding time within the first 48-72 h. Copyright © 2013 Elsevier España, S.L.U. All rights reserved.

  10. Gel phase formation in dilute triblock copolyelectrolyte complexes

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Samanvaya; Andreev, Marat; Levi, Adam E.; Goldfeld, David J.; Mao, Jun; Heller, William T.; Prabhu, Vivek M.; de Pablo, Juan J.; Tirrell, Matthew V.

    2017-02-23

    Assembly of oppositely charged triblock copolyelectrolytes into phase-separated gels at low polymer concentrations (<1% by mass) has been observed in scattering experiments and molecular dynamics simulations. Here we show that in contrast to uncharged, amphiphilic block copolymers that form discrete micelles at low concentrations and enter a phase of strongly interacting micelles in a gradual manner with increasing concentration, the formation of a dilute phase of individual micelles is prevented in polyelectrolyte complexation-driven assembly of triblock copolyelectrolytes. Gel phases form and phase separate almost instantaneously on solvation of the copolymers. Furthermore, molecular models of self-assembly demonstrate the presence of oligo-chain aggregates in early stages of copolyelectrolyte assembly, at experimentally unobservable polymer concentrations. Our discoveries contribute to the fundamental understanding of the structure and pathways of complexation-driven assemblies, and raise intriguing prospects for gel formation at extraordinarily low concentrations, with applications in tissue engineering, agriculture, water purification and theranostics.

  11. Rapid high voltage isoelectric focusing of proteins in rod gels.

    Science.gov (United States)

    Das, J

    1991-09-01

    A rapid procedure of isoelectric focusing (IEF) of proteins in polyacrylamide rod gels (i.d., 1.1 mm; length, 7.5 cm) is described. The time required for IEF can be reduced to 0.5 h by using high voltages up to 3000 V in the presence or absence of urea in the gels. When used as the first dimension of a two-dimensional technique for IEF sodium dodecyl sulphate electrophoresis, high voltage IEF gives smaller protein spots on the second dimension gel, associated with an increase in resolution. The method has been tested by a two-dimensional separation of an eye sample of the goodeid fish Xenotoca eiseni.

  12. Preparation and fluorescence properties of crystalline gel rare earth phosphates.

    Science.gov (United States)

    Onoda, Hiroaki; Funamoto, Takehiro

    2015-03-01

    An aqueous solution of sodium dihydrogen phosphate was mixed with a aqueous solution of lanthanum nitrate and stirred for 24 h, and the pH was adjusted to 11 using ammonia. The obtained phosphates were analyzed using X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry-differential thermal analysis, and scanning electron microscopy. The lanthanum phosphate gel was obtained with a large amount of water. The fluorescence of the gels was investigated by substituting a part of the lanthanum cations with cerium, terbium, and europium cations. UV-vis reflectance and fluorescence spectra of these substituted materials were obtained and analyzed. Rrare-earth phosphate gels with large amounts of water exhibited bluish purple, green, and red fluorescence when cation ratios of La/Ce = 70/30, La/Ce/Tb = 55/30/15, and La/Eu = 95/5 were used, respectively.

  13. Neutron Scattering on Impurity Nanoclusters in Gel Samples

    Directory of Open Access Journals (Sweden)

    V. B. Efimov

    2015-01-01

    Full Text Available Results of recent SANS experiments with impurity-helium gel (IHG samples in He-II are presented. We estimate the mean size of the impurity nanoparticles that form the frame of the IHG samples and discuss the possibility to use IHG samples for the production of ultracold neutrons (UCNs in He-II cooled to the temperature of a few mK, as well as the reflection of UCNs at any temperature. Our results indicate that the most promising materials for these purposes might be the heavy water gel samples with the mean sizes of D2O clusters of d~8 nm and the heavy alcohol gel samples with the mean sizes of clusters of d~15 nm.

  14. Acid-Urea Gel Electrophoresis and Western Blotting of Histones.

    Science.gov (United States)

    Hazzalin, Catherine A; Mahadevan, Louis C

    2017-01-01

    Acid-urea gel electrophoresis offers significant advantages over SDS-PAGE for analysis of post-translational protein modifications, being capable of resolving proteins of similar size but varying in charge. Hence, it can be used to separate protein variants with small charge-altering differences in primary sequence, and is particularly useful in the analysis of histones whose charge variation arises from post-translational modification, such as phosphorylation or acetylation. On acid-urea gels, histones that carry multiple modifications, each with a characteristic charge, are resolved into distinct bands, the so-called "histone ladder." Thus, the extent and distribution of different modification states of histones can be visualized. Here, we describe the analysis of histone H3 by acid-urea gel electrophoresis and western blotting.

  15. Modeling and simulation of transport phenomena in ionic gels

    Science.gov (United States)

    Leichsenring, Peter; Wallmersperger, Thomas

    2015-04-01

    Ionic hydrogels belong to the class of polyelectrolyte gels or ionic gels. Their ability to swell or shrink under different environmental conditions such as change of pH, ion concentration or temperature make them promising materials, e.g. for microsensoric or microactuatoric devices. The hydrogel swelling exhibits nonlinear effects due to the occurrence of different interacting transport phenomena. Numerical simulations are an essential part in the ongoing development of microsensors and microactuators. In order to determine transport effects due to diffusion, migration and convection a multiphase mesoscale model based on the Theory of Porous Media is applied. The governing field equations are solved in the transient regime by applying the Finite Element Method. By means of the derived numerical framework a detailed investigation of the different transport phenomena is carried out. Numerical experiments are performed to characterize the dominating transfer phenomena for ionic gels under chemical stimulation.

  16. Graphitic carbon nitride embedded hydrogels for enhanced gel electrophoresis.

    Science.gov (United States)

    Zarei, Mohammad; Ahmadzadeh, Hossein; Goharshadi, Elaheh K; Farzaneh, Ali

    2015-08-05

    Here, we show, for the first time, the use of graphitic carbon nitride (g-C3N4) nanosheets to improve the resolution and efficiency of protein separation in gel electrophoresis. By loading 0.04% (m/v) g-C3N4 nanosheets into the polyacrylamide gel at 25 °C, the thermal conductivity increased approximately 80% which resulted in 20% reduction in Joule heating and overall increase of separation efficiency. Also, polymerization of acrylamide occurred in the absence of tetramethylethylenediamine (TEMED) when the polyacrylamide gel contained g-C3N4 nanosheets. Hence, the g-C3N4 act simultaneously as a polymerization catalyst as well as heat sinks to lower Joule heating effect on band broadening. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Application of tannin gel to TRU aqueous waste treatment

    International Nuclear Information System (INIS)

    Matsumura, T.; Morikawa, K.; Maeda, A.; Nakano, Y.; Nakamura, Y.; Hamaguchi, K.; Shirato, W.; Konno, M.

    2000-01-01

    Batch experiments by simulated TRU aqueous waste using Eu, as a simulant of Am, were carried out to apply tannin gel to treatment of TRU aqueous waste, which has high nitric acid and Am concentration. From the results, reduction of adsorption amount of Eu by the impurities in the simulated waste was observed. However, the effect of the impurities will not become serious problem to construct practical process. Also, applicability of denitration by formic acid to pH conditioning for adsorption by tannin gel was examined to reduce the salt as a secondary waste arising from the neutralization for the pH conditioning. From the results of the batch experiments by the simulated waste containing formic acid, enhancement of Eu adsorption amount by the formic acid was observed. The applicability of adsorption by the tannin gel and denitration by formic acid to TRU aqueous waste treatment becomes clear from the results. (authors)

  18. Densification and crystallization behaviour of colloidal cordierite-type gels

    Directory of Open Access Journals (Sweden)

    LJILJANA KOSTIC-GVOZDENOVIC

    2001-05-01

    Full Text Available Three cordierite-type gels were prepared from an aqueous solution of Mg(NO32, a boehmite sol and silica sols of very small particle sizes. The effect of varying the silica particle size on the crystallization and densification behaviour was studied. Phase development was examined by thermal analysis and X-ray diffraction, while the densification behaviour was characterized by measuring the linear shrinkage of pellets. The activation energy of densification by viscous flow was determined using the Franckel model for non-isothermal conditions and a constant heating rate. The results show that spinel crystallizes from the colloidal gels prior to cristobalite, and their reaction gives a-cordierite, which is specific for three-phase gels. Decreasing the silica particles size lowers the cristobalite crystallization temperature and the a-cordierite formation temperature. The activation energy of densification by viscous flow is lower and the densification more efficient, the smaller the silica particles are.

  19. Study of the characterization and formulation of the decontamination gels

    International Nuclear Information System (INIS)

    Park, Youn Bong; Bang, In Bae; Bae, Bong Moon; Oh, Gyu Hwan

    2011-04-01

    To develop a chemical gel decontamination technology for a removal of non-fixed contaminants during the maintenance and decommissioning works of high radiation hot cells which have been used for a recycling or treatment of spent fuels we have prepare gels with CAB-O-SIL M-5 or Aerosil 380 as viscosifier and some non-ionic surfactants such as diethylene glycol hexyl ether, triethylene glycol dodecyl ether, polyethylene glycol 600, and triethylene glycol butyl ether. Surfactants are playing important roles in manipulating the properties of decontamination the gels. We have found the CAB-O-SIL with triethylene glycol butyl ether and Aerosil with triethylene glycol dodecyl ether systems promising for the decontamination work

  20. A comparison of 15% azelaic acid gel and 0.75% metronidazole gel in the topical treatment of papulopustular rosacea: results of a randomized trial.

    Science.gov (United States)

    Elewski, Boni E; Fleischer, Alan B; Pariser, David M

    2003-11-01

    To compare the efficacy and safety of a novel formulation of 15% azelaic acid gel (Finacea; Berlex Laboratories, Inc, Montville, NJ) with 0.75% metronidazole gel (MetroGel; Galderma Laboratories LP, Fort Worth, Tex) as topical therapy for moderate, papulopustular facial rosacea. Multicenter, double-blind, randomized, parallel-group study. Thirteen US centers. A total of 251 patients with papulopustular rosacea with persistent erythema and telangiectasia. Patients were randomized to receive azelaic acid gel or metronidazole gel twice daily for 15 weeks. Nominal and percent change in inflammatory lesion count, change in erythema and telangiectasia severity ratings, investigator's global assessment of rosacea, and investigator's and patient's overall improvement ratings. Azelaic acid gel was superior to metronidazole gel in reduction of mean nominal lesion count (-12.9 vs -10.7, respectively) (P =.003) and mean percent decrease in inflammatory lesions (-72.7% vs -55.8%, respectively) (Pazelaic acid gel-treated patients were rated improved vs 42% of metronidazole gel-treated patients (P =.02). The effectiveness of metronidazole gel on these variables seemed to plateau after week 8, whereas azelaic acid gel demonstrated progressive improvement through week 15. Neither treatment had a clinically appreciable effect on telangiectasia. Both the investigator's global assessment (P =.02) and overall assessment of improvement (P =.005) showed a significant therapeutic advantage for azelaic acid gel. Azelaic acid gel also scored higher on the patient's overall assessment of efficacy. Both treatments were rated as having high cosmetic acceptability. No serious or systemic treatment-related adverse events were reported in either group. Use of 15% azelaic acid gel twice daily for 15 weeks demonstrated significant superiority over using 0.75% metronidazole gel in improving principal signs of rosacea (inflammatory lesions and erythema).

  1. A mucoadhesive in situ gel delivery system for paclitaxel.

    Science.gov (United States)

    Jauhari, Saurabh; Dash, Alekha K

    2006-06-02

    MUC1 gene encodes a transmembrane mucin glycoprotein that is overexpressed in human breast cancer and colon cancer. The objective of this study was to develop an in situ gel delivery system containing paclitaxel (PTX) and mucoadhesives for sustained and targeted delivery of anticancer drugs. The delivery system consisted of chitosan and glyceryl monooleate (GMO) in 0.33M citric acid containing PTX. The in vitro release of PTX from the gel was performed in presence and absence of Tween 80 at drug loads of 0.18%, 0.30%, and 0.54% (wt/wt), in Sorensen's phosphate buffer (pH 7.4) at 37 degrees C. Different mucin-producing cell lines (Calu-3>Caco-2) were selected for PTX transport studies. Transport of PTX from solution and gel delivery system was performed in side by side diffusion chambers from apical to basal (A-B) and basal to apical (B-A) directions. In vitro release studies revealed that within 4 hours, only 7.61% +/- 0.19%, 12.0% +/- 0.98%, 31.7% +/- 0.40% of PTX were released from 0.18%, 0.30%, and 0.54% drug-loaded gel formulation, respectively, in absence of Tween 80. However, in presence of surfactant (0.05% wt/vol) in the dissolution medium, percentages of PTX released were 28.1% +/- 4.35%, 44.2% +/- 6.35%, and 97.1% +/- 1.22%, respectively. Paclitaxel has shown a polarized transport in all the cell monolayers with B-A transport 2 to 4 times higher than in the A-B direction. The highest mucin-producing cell line (Calu-3) has shown the lowest percentage of PTX transport from gels as compared with Caco-2 cells. Transport of PTX from mucoadhesive gels was shown to be influenced by the mucin-producing capability of cell.

  2. Optical Sensors for Biomolecules Using Nanoporous Sol-Gel Materials

    Science.gov (United States)

    Fang, Jonathan; Zhou, Jing C.; Lan, Esther H.; Dunn, Bruce; Gillman, Patricia L.; Smith, Scott M.

    2004-01-01

    An important consideration for space missions to Mars is the ability to detect biosignatures. Solid-state sensing elements for optical detection of biological entities are possible using sol-gel based biologically active materials. We have used these materials as optical sensing elements in a variety of bioassays, including immunoassays and enzyme assays. By immobilizing an appropriate biomolecule in the sol-gel sensing element, we have successfully detected analytes such as amino acids and hormones. In the case of the amino acid glutamate, the enzyme glutamate dehydrogenase was the immobilized molecule, whereas in the case of the hormone cortisol, an anti-cortisol antibody was immobilized in the sensing element. In this previous work with immobilized enzymes and antibodies, excellent sensitivity and specificity were demonstrated in a variety of formats including bulk materials, thin films and fibers. We believe that the sol-gel approach is an attractive platform for bioastronautics sensing applications because of the ability to detect a wide range of entities such as amino acids, fatty acids, hopanes, porphyrins, etc. The sol-gel approach produces an optically transparent 3D silica matrix that forms around the biomolecule of interest, thus stabilizing its structure and functionality while allowing for optical detection. This encapsulation process protects the biomolecule and leads to a more "rugged" sensor. The nanoporous structure of the sol-gel matrix allows diffusion of small target molecules but keeps larger, biomolecules immobilized in the pores. We are currently developing these biologically active sol-gel materials into small portable devices for on-orbit cortisol detection

  3. Development of Smart Optical Gels with Highly Magnetically Responsive Bicelles.

    Science.gov (United States)

    Isabettini, Stéphane; Stucki, Sandro; Massabni, Sarah; Baumgartner, Mirjam E; Reckey, Pernille Q; Kohlbrecher, Joachim; Ishikawa, Takashi; Windhab, Erich J; Fischer, Peter; Kuster, Simon

    2018-03-14

    Hydrogels delivering on-demand tailorable optical properties are formidable smart materials with promising perspectives in numerous fields, including the development of modern sensors and switches, the essential quality criterion being a defined and readily measured response to environmental changes. Lanthanide ion (Ln 3+ )-chelating bicelles are interesting building blocks for such materials because of their magnetic responsive nature. Imbedding these phospholipid-based nanodiscs in a magnetically aligned state in gelatin permits an orientation-dependent retardation of polarized light. The resulting tailorable anisotropy gives the gel a well-defined optical signature observed as a birefringence signal. These phenomena were only reported for a single bicelle-gelatin pair and required high magnetic field strengths of 8 T. Herein, we demonstrate the versatility and enhance the viability of this technology with a new generation of aminocholesterol (Chol-NH 2 )-doped bicelles imbedded in two different types of gelatin. The highly magnetically responsive nature of the bicelles allowed to gel the anisotropy at commercially viable magnetic field strengths between 1 and 3 T. Thermoreversible gels with a unique optical signature were generated by exposing the system to various temperature conditions and external magnetic field strengths. The resulting optical properties were a signature of the gel's environmental history, effectively acting as a sensor. Solutions containing the bicelles simultaneously aligning parallel and perpendicular to the magnetic field directions were obtained by mixing samples chelating Tm 3+ and Dy 3+ . These systems were successfully gelled, providing a material with two distinct temperature-dependent optical characteristics. The high degree of tunability in the magnetic response of the bicelles enables encryption of the gel's optical properties. The proposed gels are viable candidates for temperature tracking of sensitive goods and provide

  4. Does Prebiopsy, Nonsterile Ultrasonography Gel Affect Biopsy-Site Asepsis?

    International Nuclear Information System (INIS)

    Gurel, Kamil; Karabay, Oguz; Gurel, Safiye; Hildebolt, Charles

    2008-01-01

    Purpose. The purpose of this study was to determine the extent to which the use of nonsterile gel, prior to antiseptic procedures in ultrasonography (US)-guided percutaneous biopsies, results in contamination of the biopsy site. Materials and Methods. Patients referred for US-guided percutaneous biopsies were included in this study. Transmission material used for US evaluation before biopsy-site antiseptic procedures were performed was either nonsterile gel or sterile saline. Patients were randomly assigned to two groups: nonsterile gel (n = 30) and sterile saline (n = 30). Before the transmission material was used and after antiseptic procedures were performed, microbial swabs of a 10-cm 2 -diameter area were obtained at the biopsy site. Swabs were also obtained from the gel, saline, and povidine-iodine. Inoculated specimen plates were incubated at 37 o C under aerobic conditions, and the numbers of colony-forming units recorded. Nominal logistic regression analysis was used to calculate the odds of postantisepsis bacterial growth (after antiseptic procedures were performed) based on group, gender, coincidental disease (diabetes, chronic renal failure, and malignancy), biopsy-site location (head and neck or breast and abdomen), and local factors (skin fold, skin tag, and hair). Results. The following odds ratios (adjusted for the other variables) and their 95% confidence intervals were calculated: (1) group (2.9 [0.8-11.1]; p = 0.10); (2) gender (1.2 [0.3-5.2]; p = 0.78); (3) coincidental disease (7.6 [0.9-166.7]; p = 0.09); (4) biopsy site location (6.2 [1.4-31.3]; p = 0.02); and (5) local factors (7.0 [1.6-36.0]; p = 0.01). No bacterial growth occurred with swabs obtained from gel, povidine-iodine, or saline. Conclusion. We conclude that nonsterile gel used prior to percutaneous biopsy does not affect biopsy-site asepsis

  5. 3D jet printer of edible gels for food creation

    Science.gov (United States)

    Serizawa, Ryo; Shitara, Mariko; Gong, Jin; Makino, Masato; Kabir, M. Hasnat; Furukawa, Hidemitsu

    2014-03-01

    In recent years, aging is progressing in Japan. Elderly people can't swallow the food well. So, the need of soft food is increasing greatly with the aging of the population. There are so few satisfying foods for the elderly to enjoy a meal. An equipment of printing soft food gives the elderly a big dream and is promising. In this study, we aim at developing a 3D edible gel printer in order to make soft food for the elderly. We made a prototype of the 3D edible gel printer. The printer consists of syringe pump and dispenser. The syringe pump extrudes the solution. The dispenser allows to model threedimensional objects. We use agar solution as the ink to carry out the printing. Agar's gelation deeply depends on temperature. Therefore temperature control of the solution is important to mold optimal shapes because the physical crosslinking network of agar's solution is instable. We succeeded in making the gels and plate-shape gel using the 3D edible gel printer. Further more, in order to increase the gelation speed agar's solution, we changed the dispenser and the printing test is being done now. 4 kinds of soft food prepared from agar and gelatin were printed by the 3D edible gel printer. The compression tests of the printed soft food samples were done and their hardness is measured because the hardness is one of very important factors which influence the food texture greatly. In the future, the viscosity of the agar solution or other food ink should be adjusted to suitable for printing.

  6. Improving precision in gel electrophoresis by stepwisely decreasing variance components.

    Science.gov (United States)

    Schröder, Simone; Brandmüller, Asita; Deng, Xi; Ahmed, Aftab; Wätzig, Hermann

    2009-10-15

    Many methods have been developed in order to increase selectivity and sensitivity in proteome research. However, gel electrophoresis (GE) which is one of the major techniques in this area, is still known for its often unsatisfactory precision. Percental relative standard deviations (RSD%) up to 60% have been reported. In this case the improvement of precision and sensitivity is absolutely essential, particularly for the quality control of biopharmaceuticals. Our work reflects the remarkable and completely irregular changes of the background signal from gel to gel. This irregularity was identified as one of the governing error sources. These background changes can be strongly reduced by using a signal detection in the near-infrared (NIR) range. This particular detection method provides the most sensitive approach for conventional CCB (Colloidal Coomassie Blue) stained gels, which is reflected in a total error of just 5% (RSD%). In order to further investigate variance components in GE, an experimental Plackett-Burman screening design was performed. The influence of seven potential factors on the precision was investigated using 10 proteins with different properties analyzed by NIR detection. The results emphasized the individuality of the proteins. Completely different factors were identified to be significant for each protein. However, out of seven investigated parameters, just four showed a significant effect on some proteins, namely the parameters of: destaining time, staining temperature, changes of detergent additives (SDS and LDS) in the sample buffer, and the age of the gels. As a result, precision can only be improved individually for each protein or protein classes. Further understanding of the unique properties of proteins should enable us to improve the precision in gel electrophoresis.

  7. Measurement of a PAGAT gel dosimeter by ultrasound computed tomography

    Science.gov (United States)

    Khoei, S.; Trapp, J. V.; Langton, C. M.

    2013-06-01

    In this work we used a 3D quantitative CT ultrasound imaging system to characterise polymer gel dosimeters. The system comprised of two identical 5 MHz 128 element phased-array ultrasound transducers co-axially aligned and submerged in water as a coupling agent. Rotational and translational movement of the gel dosimeter sample between the transducers were performed using a robotic arm. Ultrasound signals were generated and received using an Olympus Omniscan unit. Dose sensitivity of attenuation and time of flight ultrasonic parameters were assessed using this system.

  8. The characterisation of a genipin-gelatin gel dosimeter

    International Nuclear Information System (INIS)

    Davies, J B; Bosi, S; Baldock, C

    2010-01-01

    Genipin cross links gelatin to slowly form a blue colour that bleaches upon irradiation. Spectrophotometric measurements of the absorbance change following irradiation to doses up to 100 Gy gives a linear dose response for certain concentrations of the gel ingredients; genipin, gelatin and sulphuric acid. Dose sensitivity increases with increasing concentrations of sulphuric acid and genipin and is also strongly dependent on the time allowed for the genipin-gelatin cross linking reaction (referred to here as blending) to take place. The optimum formulation of this gel was found for genipin concentration between 0.3 - 0.5 mM and blending time of at least 4 h.

  9. Strain identification in Rhizobium by starch gel electrophoresis of isoenzymes

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen; Nielsen, G.

    1985-01-01

    Sonieated extracts of rhizobia, especiaUy Rhizobium leguminosarum from pea and vetch, were run in horizontal starch gel electrophoresis in the cold. The rhizobia were grown on agar on a slime suppressing substrate of tryptone-yeast extract-CaCl2 with small amounts of mannitol, sorbitol and arabin......Sonieated extracts of rhizobia, especiaUy Rhizobium leguminosarum from pea and vetch, were run in horizontal starch gel electrophoresis in the cold. The rhizobia were grown on agar on a slime suppressing substrate of tryptone-yeast extract-CaCl2 with small amounts of mannitol, sorbitol...

  10. A mucoadhesive in situ gel delivery system for paclitaxel

    OpenAIRE

    Jauhari, Saurabh; Dash, Alekha K.

    2006-01-01

    MUC1 gene encodes a transmembrane mucin glycoprotein that is overexpressed in human breast cancer and colon cancer. The objective of this study was to develop an in situ gel delivery system containing paclitaxel (PTX) and mucoadhesives for sustained and targeted delivery of anticancer drugs. The delivery system consisted of chitosan and glyceryl monooleate (GMO) in 0.33M citric acid containing PTX. The in vitro release of PTX from the gel was performed in presence and absence of Tween 80 at d...

  11. Surfactant Enhanced Chromium Removal Using a Silica Gel Column

    Directory of Open Access Journals (Sweden)

    N. Rajesh

    2001-06-01

    Full Text Available A simple and rapid method is proposed for the removal of chromium based on its adsorption as an ion pair with Cetyl Trimethyl Ammonium Bromide (CTABr on a silica gel colurnn. The surfactant (CTABr is bonded to chromate by electrostatic force of attraction and the resulting ion-association complex is held on a silica gel column. The resulting solution from the column is analyzed for chromium by the standard diphenyl carbazide spectrophotometric procedure. The method has been applied successfully to study the recovery of chromium in various synthetic mixtures.

  12. Comparative gel electrophoresis analysis of helical junctions in RNA.

    Science.gov (United States)

    Lilley, David M J

    2009-01-01

    Comparative gel electrophoresis provides information on the relative angles subtended between helical arms at a branchpoint in RNA. It is based upon the comparison of electrophoretic mobility in polyacrylamide gels of species containing two long arms, with the remaining one(s) being significantly shorter. Although the method currently lacks a really well-established basis of physical theory, it is very powerful, yet simple to apply. It has had a number of significant successes in RNA, DNA and DNA-protein complexes, and in all cases to date the results have stood the test of time and eventual comparison with crystallographic analysis. Copyright © 2009 Elsevier Inc. All rights reserved.

  13. Separation of long RNA by agarose-formaldehyde gel electrophoresis.

    Science.gov (United States)

    Mansour, Farrah H; Pestov, Dimitri G

    2013-10-01

    We describe a method to facilitate electrophoretic separation of high-molecular-weight RNA species, such as ribosomal RNAs and their precursors, on agarose-formaldehyde gels. Two alternative "pK-matched" buffer systems were substituted for the traditionally used Mops-based conductive medium. The key advantages include shortened run times, a 5-fold reduction in formaldehyde concentration, a significantly improved resolution of long RNAs, and consistency in separation. The new procedure has a streamlined work flow that helps to minimize errors and is broadly applicable to agarose gel electrophoresis of RNA samples and their subsequent analysis by Northern blotting. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Polyacrylamide Gel Electrophoresis for Purification of Large Amounts of RNA.

    Science.gov (United States)

    Meyer, Mélanie; Masquida, Benoît

    2016-01-01

    Polyacrylamide gel electrophoresis (PAGE) constitutes a powerful technique for the efficient purification of RNA molecules dedicated to applications that require high purity levels. PAGE allows for the fractionation of RNA obtained from cell extracts, chemical or enzymatic synthesis, or modification experiments. Native or denaturing conditions can be chosen for analytical or preparative-scale separations and the nucleotide resolution can be tuned by changing the percentage and reticulation of the gel material. In this protocol, we focus on the preparation of milligram-scale amounts of ~200 nucleotides (nt) RNA molecules that were used in subsequent crystallization experiments.

  15. Purification and cloning of DNA fragments fractionated on agarose gels.

    Science.gov (United States)

    Griffin, H G; Gasson, M J

    1995-04-01

    Purification of DNA fragments from acrylamide or agarose gels is a commonly used technique in the molecular biology laboratory. This article describes a rapid, efficient, and inexpensive method of purifying DNA fractions from an agarose gel. The purified DNA is suitable for use in a wide range of applications including ligation using DNA ligase. The procedure uses standard high-melting-temperature agarose and normal TBE electrophoresis buffer. In addition, the protocol does not involve the use of highly toxic organic solvents such as phenol.

  16. A Molecular View of Liquid Crystalline Elastomers and Gels

    Science.gov (United States)

    de Pablo, Juan

    2011-03-01

    A combination of Monte Carlo and molecular dynamics simulations is used to examine the order-disorder transitions that arise in model liquid crystalline elastomers and colloidal gels as a function of concentration and strain, respectively. Two models are considered. In the first, a lattice model is used to represent a colloidal gel of nematogens and nanoparticles. In the second, a cross-linked elastomer of Gay-Berne mesogens is adopted to examine the order-disroder transition that arises as a function of strain. The results of simulations are compared to those of recent experiments for these two classes of systems.

  17. Scaffold architecture and fibrin gels promote meniscal cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Pawelec, K. M., E-mail: pawelec.km@gmail.com, E-mail: jw626@cam.ac.uk; Best, S. M.; Cameron, R. E. [Cambridge Centre for Medical Materials, Materials Science and Metallurgy Department, University of Cambridge, Cambridge CB3 0FS (United Kingdom); Wardale, R. J., E-mail: pawelec.km@gmail.com, E-mail: jw626@cam.ac.uk [Division of Trauma and Orthopaedic Surgery, Department of Surgery, University of Cambridge, Cambridge CB2 2QQ (United Kingdom)

    2015-01-01

    Stability of the knee relies on the meniscus, a complex connective tissue with poor healing ability. Current meniscal tissue engineering is inadequate, as the signals for increasing meniscal cell proliferation have not been established. In this study, collagen scaffold structure, isotropic or aligned, and fibrin gel addition were tested. Metabolic activity was promoted by fibrin addition. Cellular proliferation, however, was significantly increased by both aligned architectures and fibrin addition. None of the constructs impaired collagen type I production or triggered adverse inflammatory responses. It was demonstrated that both fibrin gel addition and optimized scaffold architecture effectively promote meniscal cell proliferation.

  18. Fluid diversion and sweep improvement with chemical gels in oil recovery processes

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-04-01

    The objectives of this project are to identify the mechanisms by which gel treatments divert fluids in reservoirs and to establish where and how gel treatments are best applied. Several different types of gelants are being examined. This research is directed at gel applications in water injection wells, in production wells, and in high-pressure gas floods. The work will establish how the flow properties of gels and gelling agents are influenced by permeability, lithology, and wettability. Other goals include determining the proper placement of gelants, the stability of in-place gels, and the types of gels required for the various oil recovery processes and for different scales of reservoir heterogeneity. This report describes progress made during the first year of this three-year study the following tasks: gel screening studies; impact of gelation pH, rock permeability, and lithology on the performance of a monomer-based gel; preliminary study of the permeability reduction for CO{sub 2} and water using a resorcinol-formaldehyde gel; preliminary study of permeability reduction for oil and water using a resorcinol-formaldehyde gel; rheology of Cr(III)-xanthan gel and gelants in porous media; impact of diffusion, dispersion, and viscous fingering on gel placement in injection wells; examination of flow-profile changes for field applications of gel treatments in injection wells; and placement of gels in production wells. Papers have been indexed separately for inclusion on the data base.

  19. The application of sol-gel and gel-precipitation technology to the preparation of spheres of lithium aluminate

    International Nuclear Information System (INIS)

    Turner, C.W.; Clatworthy, B.C.

    1988-01-01

    A concept for preparing spheres of lithium aluminate by either a sol-gel or gel-precipitation process based on the precipitation of a lithium salt in the pores of an aluminum hydroxide gel has been tested and has proved to be not feasible. The addition of any of the following salts: lithium formate; lithium oxalate; or lithium carbonate to a solution of aluminum nitrate hydrolysed to a hydroxyl number greater than 2.85 caused the hydrolysed solution, or sol, to gel immediately. The addition of lithium formate to a dialysed sol caused it to flocculate at low pH and prevented the transformation from a sol to a gel from occurring at elevated pH. This behaviour was linked to the adsorption of the anions - formate, oxalate, or carbonate - onto the surface of the sol particles. Hydrolysis of solutions of aluminum nitrate together with either lithium formate, lithium oxalate, or lithium carbonate, such that the mole ratio of aluminum to lithium was 1:1, resulted in the formation of a crystalline precipitate containing both lithium and aluminum. The lithium to aluminum ratio of the precipitate was 0.44:1 when lithium was introduced as the carbonate. Spheres could be made by gel-precipitation if the viscosity of the feed solution was first increased to 200 cps by the addition of polyvinyl alcohol. However, the lithium not chemically bound in the precipitate diffused out of the spheres during gelation. Heating of the lithium-deficient spheres to 950 degrees C produced a mixture of lithium aluminate and the spinel phase, LiAl 5 O 8

  20. The preparation and characterization of a lithium borate glass prepared by the gel technique

    Science.gov (United States)

    Weinberg, M. C.; Neilson, G. F.; Smith, G. L.; Dunn, B.; Moore, G. S.; Mackenzie, J. D.

    1985-01-01

    The preparation of an amorphous lithium borate gel by the metal organic procedure is described. In addition, a preliminary evaluation of the behavior of the gel upon heating is given. In particular the crystallization tendency of the gel is studied with the aid of DTA and X-ray diffraction, and the structural changes in the gel are monitored with the aid of IR spectroscopy. The glass produced from the lithium borate gel is compared to both the gel precursor material and a glass of similar composition prepared by conventional techniques. Specifically, the relevant water contents, crystallization behavior, and structural features are contrasted.

  1. Study of laser action of Coumarine-153 incorporated in sol gel made silica/poly(propylene oxide) nanocomposite gels

    Science.gov (United States)

    Stathatos, Elias; Lianos, Panagiotis; Stangar, Urska Lavrencic; Orel, Boris

    2001-09-01

    Coumarin-153 (C-153) has been incorporated by the sol-gel method into transparent nanocomposite matrices made by using a precursor composed of a poly(propylene oxide) (PPO) chain covalently linked by urea bridges with two end triethoxysilane groups. The solid gels can be used without any further treatment as active components in a dye laser, providing a rather wide range of laser emission. This range is further widened by exploiting the solvatochromic effect of coumarin and the different polarity of the solubilization sites provided by nanocomposites of various PPO chain sizes.

  2. Gel-based and gel-free proteome data associated with controlled deterioration treatment ofGlycine maxseeds.

    Science.gov (United States)

    Min, Cheol Woo; Lee, Seo Hyun; Cheon, Ye Eun; Han, Won Young; Ko, Jong Min; Kang, Hang Won; Kim, Yong Chul; Agrawal, Ganesh Kumar; Rakwal, Randeep; Gupta, Ravi; Kim, Sun Tae

    2017-12-01

    Data presented here are associated with the article: "In-depth proteomic analysis of soybean ( Glycine max ) seeds during controlled deterioration treatment (CDT) reveals a shift in seed metabolism" (Min et al., 2017) [1]. Seed deterioration is one of the major problems, affecting the seed quality, viability, and vigor in a negative manner. Here, we display the gel-based and gel-free proteomic data, associated with the CDT in soybean seeds. The present data was obtained from 2-DE, shotgun proteomic analysis (label-free quantitative proteomic analysis) using Q-Exactive, and gene ontology analysis associated with CDT in soybean seeds (Min et al., 2017) [1].

  3. On the layer structure of vanadium pentoxide gels. Comment on `molecular dynamic simulation of the vanadium pentoxide gel host`

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Takeshi [Department of Fundamental Energy Science, Graduate School of Energy Sciences, Kyoto University, Kyoto (Japan); Oka, Yoshio [Department of Natural Environment Sciences, Faculty of Integrated Human Studies, Kyoto University, Kyoto (Japan)

    1997-04-16

    A comment on the article entitled `molecular dynamic simulation of the vanadium pentoxide gel host` [J. Linde and J.O. Thomas, Solid State Ionics 85 (1996) 1] is presented concerning the model structure of the V{sub 2}O{sub 5} layer of vanadium pentoxide gels. The double-layer structure used in the simulation was derived from the crystalline V{sub 2}O{sub 5}. This model structure significantly differs from the double-sheet type determined by the X-ray Rietvelt method. The simulation should be recalculated based on the double-sheet type V{sub 2}O{sub 5} layer

  4. Gel Electrophoresis and Fluorescamine Methods for the Detection of ...

    African Journals Online (AJOL)

    were the most proteolysed, indicating that the high temperatures (110, 120, 130 and 142 ˚C for 2s) lowered proteolysis through inactivation of heat resistant native enzymes possibly plasmin and hence decreased milk's susceptibility to spoilage. Key words: proteolysis, fluorescamine, gel electrophoresis, plasmin, isoelectric ...

  5. A Conductive Gel for the Plotting of Equipotential Lines

    Science.gov (United States)

    Elizalde-Torres, J.; González-Cardel, M.; Vega-Murguía, E. J.; Castillo-González, I.; Rodríguez-Nava, M.

    2015-01-01

    This paper presents the development of a conductive gel that can be used to measure the electrical potential differences on its surface, and has enough consistency to plot equipotential lines. It has a gelation time of less than 10 min, and is suitable for implementing learning experiences in a physics teaching laboratory in a 90 min session. To…

  6. Ethanol-Gel Sclerotherapy of Venous Malformations: Effectiveness and Safety.

    Science.gov (United States)

    Teusch, Veronika I; Wohlgemuth, Walter A; Hammer, Simone; Piehler, Armin P; Müller-Wille, René; Goessmann, Holger; Uller, Wibke

    2017-12-01

    In the treatment of venous malformations, ethanol may be administered in a gelified form to increase local effects and reduce systemic ones. The purpose of this prospective study was to evaluate the efficacy and safety of a commercially available viscous ethanol gel in the treatment of venous malformations. Thirty-one patients (mean age, 23.4 years; age range, 6.6-46.5 years) with venous malformations were prospectively scheduled for two ethanol-gel sclerotherapy sessions. Venous malformations were located at the lower extremity (n = 18), the upper extremity (n = 9), and the face (n = 4). Questionnaires to assess pain, clinical examinations, professional photographs, and contrast-enhanced MRI of the venous malformations were performed before and after therapy to measure therapy-induced changes. Two experienced radiologists blinded to the examination date and clinical status compared photographs and MR images before and after treatment. A mean of 4.2 mL of ethanol gel were administered per session. The technical success rate was 100%. Clinical success, defined as improvement or resolution of symptoms, was noted in 81% of patients. Mean pain score decreased, and the difference was statistically significant (3.9 vs 3.1, p = 0.005). In 54 treatment sessions where follow-up was available, four minor complications occurred. Comparison of photographs and MR images before and after treatment showed improvement in 35% and 93% of patients, respectively. Ethanol gel is an effective and safe sclerosing agent in the treatment of venous malformations.

  7. The Bioadhesive and Rheological properties of some fluconazole gels

    African Journals Online (AJOL)

    An oscillatory rheological technique was employed using a parallel plate viscometer to determine the rheological properties of the formulations. Two dyes, erythrosine and amaranth were added to elucidate diffusional processes occurring during mucociliary transport of the gels. The results obtained indicate that high ...

  8. DSC and conductivity studies on PVA based proton conducting gel ...

    Indian Academy of Sciences (India)

    Unknown

    in value of n. Further, addition of PVA also enhances the viscosity of the system which causes a fall in mobility of charge carriers. Both these factors coupled ... of polymeric chain. In this model, they considered poly- meric gel comprising of dissociated ions, ion pairs in the solvent and polymeric chains which may have folded ...

  9. Cervical ripening with prostaglandin gel and hygroscopic dilators.

    Science.gov (United States)

    Hibbard, J U; Shashoua, A; Adamczyk, C; Ismail, M

    1998-01-01

    OBJECTIVE: To study the effectiveness and morbidity of adding hygroscopic cervical dilators to prostaglandin gel for cervical ripening and labor induction. STUDY DESIGN: Patients of at least 34 weeks' gestation with a medical indication for induction of labor and with a modified Bishop score of 5 or less were randomized to receive either prostaglandin gel or prostaglandin gel with hygroscopic cervical dilators. Primary outcomes were time to delivery, change in cervical score, and infection. Secondary outcomes included cesarean delivery rate and deliveries before 24 hours of induction. Continuous variables were analyzed by Wilcoxon sum rank test and categorical data by chi-square or Fisher exact test, with P intracervical prostaglandin alone and 23 patients received intracervical prostaglandin plus hygroscopic dilators. No demographic differences were noted between the groups. After six hours of ripening, the combined group achieved a greater change in Bishop score (3.6 vs. 2.1, P = 0.007) and tended to have a shorter induction time (21.7 vs. 26.4 hours, P = 0.085). The combined therapy group had a higher infection rate than the prostaglandin-only group (59% vs. 12%, P = 0.003). CONCLUSION: Combining cervical dilators with prostaglandin gel provides more effective cervical ripening and a more rapid induction to delivery interval than prostaglandin alone but with a significant and prohibitive rate of infection. PMID:9678143

  10. Conductivity behaviour of polymer gel electrolytes: Role of polymer

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Polymer is an important constituent of polymer gel electrolytes along with salt and solvent. The salt provides ions for conduction and the solvent helps in the dissolution of the salt and also provides the medium for ion conduction. Although the polymer added provides mechanical stability to the electrolytes yet.

  11. Preparation of an efficient humidity indicating silica gel from rice ...

    Indian Academy of Sciences (India)

    Administrator

    development behaviour of the gel were investigated. The moisture adsorption capacity and the regeneration charac- teristic of the desiccant were also investigated. 2. Experimental. RHA was collected from a local rice mill. Sodium hydroxide (Laboratory Grade, Loba, India), hydrochloric acid (Loba, India) and CoCl2⋅6H2O ...

  12. Growth and characterization of gel grown pure and mixed iron ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Several applications of iron tartrate and manganese tartrate compounds are reported in the literature. In the present investigation, we have grown pure and mixed iron (II)–manganese levo-tartrate crystals by single diffusion gel growth technique. Crystals with spherulitic morphology were harvested. The colouration ...

  13. Time to first fracture affects sweetness of gels

    NARCIS (Netherlands)

    Sala, G.; Stieger, M.A.

    2013-01-01

    The aim of this study was to investigate the influence of the breakdown behaviour on sweetness intensity of gelled model foods. Emulsion-filled gelatine/agar gels varying mainly in fracture strain (eF) were used. The fracture strain was modified by changing either the ratio between gelatine and agar

  14. Bioactive nanocrystalline wollastonite synthesized by sol–gel ...

    Indian Academy of Sciences (India)

    The sol–gel combustion method was employed to synthesize the nanocrystalline wollastonite by taking the raw eggshell powder as a calcium source and TEOS as a source of silicate. Glycine was used as a reductant or fuel and nitrate ions present in metal nitrate acts as an oxidizer. The phase purity of the wollastonite was ...

  15. Aloe arborescens aqueous gel extract alters the activities of key ...

    African Journals Online (AJOL)

    The present study investigated the antidiabetic activity and the possible mechanisms of action of aqueous extract of Aloe arborescens leaf gel (AALGEt) on normal and alloxan-induced diabetic rats. Diabetes was induced in 12 h fasted rats by intraperitoneal injection of 140 mg/kg body weight of alloxan. Blood glucose ...

  16. New decontamination techniques: chemical gels, electropolishing and abrasives

    International Nuclear Information System (INIS)

    Brunel, G.; Gauchon, J.P.; Kervegant, Y.; Josso, F.

    1991-01-01

    The decommissioning of nuclear installations requires decontamination techniques that are efficient, simple to apply and producing a small amount of wastes, which are easy to process. With a view to this, three decontamination methods, which appear to be particularly suited to decommissioning, have been studied. These three methods are: - spraying of gels carrying chemical decontaminating agents, - electropolishing with a swab device, - abrasives blasting. After parametric tests on non-radioactive and active samples, the industrial application of these methods in the dismantling of installations was studied. These industrial applications concern: - decontamination of pieces coming from the German BWR ISAR by immersion and gel spraying, - decontamination, mainly by gel spraying, and dismantling of the BRENNILIS bituminisation plant, - decontamination of part of the cooling circuit of the graphite gas reactor G2 by gel spraying, - decontamination of a component of the FBR SuperPhenix, using dry abrasives blasting. During the first three applications, generated secondary wastes volume and form were determined. 33 tabs., 16 figs., 12 refs

  17. Gel table - RPD | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available switchLanguage; BLAST Search Image Search Home About Archive Update History Data ...d_main.zip File URL: ftp://ftp.biosciencedbc.jp/archive/rpd/LATEST/rpd_main.zip File size: 1 KB Simple searc...iption Download License Update History of This Database Site Policy | Contact Us Gel table - RPD | LSDB Archive ...

  18. Gel Electrophoresis and Fluorescamine Methods for the Detection of ...

    African Journals Online (AJOL)

    For the fluorescamine method, clarification was achieved by isoelectric precipitation and precipitation with acid to obtain pH 4.6 and 6% TCA soluble extracts respectively. Non-clarified samples were used for gel electrophoresis. Both methods confirmed that raw milk and milk processed at 85/15s were the most proteolysed, ...

  19. Sol-Gel/Hydrothermal Synthesis of Mixed Metal Oxide

    African Journals Online (AJOL)

    Mixed metal oxides of titanium and zinc nanocomposites were prepared through sol-gel method under hydrothermal condition ... Keywords: Nanocomposites, Titanium dioxide, Zinc oxide, Particle sizes, Optical property, X-Ray Diffraction. ABSTRACT. 321 ... doping with other semiconductors like zinc oxide, aluminium oxide ...

  20. Evaluation and Selection of Gel Base for the Formulation of ...

    African Journals Online (AJOL)

    as well as for skin protection [6-12]. At present only ointments, creams and solutions containing dexpanthenol are available in the pharmaceutical market for external use. The aim of this study was to formulate dexpanthenol gels and to select the one which has the best rheological and drug release properties using in vitro ...

  1. Thermal behaviour of strontium tartrate single crystals grown in gel

    Indian Academy of Sciences (India)

    Thermal behaviour of strontium tartrate crystals grown with the aid of sodium metasilicate gel is investigated using thermogravimetry (TG) and differential thermal analysis (DTA). Effect of magnetic field and dopant (Pb)2+ on the crystal stability is also studied using thermal analysis. This study reveals that water molecules are ...

  2. Assessment of Chronic Administration of Aloe Vera Gel On ...

    African Journals Online (AJOL)

    The study was designed to investigate the effects of chronic administration of Aloe vera gel extract on markers of hepatic damage, lipid profiles and erythrocyte osmotic fragility using the Wistar rats. Forty male Wistar rats divided into four groups of ten rats per group were used in the study. Group I which served as the control ...

  3. Growth and micro-topographical studies of gel grown cholesterol ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Cholesterol (C27H46O) is the most abundant and best-known steroid in the animal kingdom. The in vitro crystallization of this important biomaterial has been attempted by few researchers. Here we are reporting crystallization of pure cholesterol monohydrate crystals in gel medium. It is found that the morpho-.

  4. Crystallization of mixed rare earth (didymium) molybdates in silica gel

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Experiments on the growth of mixed rare earth (didymium—a combination of La, Nd, Pr and Sm) molybdates in silica gel medium are reported. The optimum conditions conducive for the growth of these crystals are described and discussed. Concentration programming is reported to enhance the size of crystals by.

  5. Process of forming a sol-gel/metal hydride composite

    Science.gov (United States)

    Congdon, James W [Aiken, SC

    2009-03-17

    An external gelation process is described which produces granules of metal hydride particles contained within a sol-gel matrix. The resulting granules are dimensionally stable and are useful for applications such as hydrogen separation and hydrogen purification. An additional coating technique for strengthening the granules is also provided.

  6. ARSENIC REMOVAL USING SOL-GEL SYNTHESIZED TITANIUM DIOXIDE NANOPARTICLES

    Science.gov (United States)

    In this study, the effectiveness of TiO2 nanoparticles in arsenic adsorption was examined. TiO2 particles (LS) were synthesized via sol-gel techniques and characterized for their crystallinity, surface area and pore volume. Batch adsorption studies were perf...

  7. Recolonization of mutans Streptococci after application of chlorhexidine gel.

    Science.gov (United States)

    Vale, Glauber Campos; Cury, Altair Antoninha Del Bel; Arthur, Rodrigo Alex; Cury, Jaime Aparecido; Tabchoury, Cínthia Pereira Machado

    2014-01-01

    Streptococcus mutans is specifically suppressed by intensive treatment with chlorhexidine gel, but the time for recolonization and the effect on other oral bacteria are not totally clear. In this study, recolonization of mutans streptococci was evaluated in nine healthy adult volunteers, who were highly colonized with this microorganism. Stimulated saliva was collected before (baseline) and at 1, 7, 14, 21 and 28 days after application of 1% chlorhexidine gel on volunteers' teeth for two consecutive days. On each day, the gel was applied using disposable trays for 3 x 5 min with intervals of 5 min between each application. Saliva was plated on blood agar to determine total microorganisms (TM); on mitis salivarius agar to determine total streptococci (TS) and on mitis salivarius agar plus bacitracin to determine mutans streptococci (MS). Chlorhexidine was capable of reducing the counts of MS and the proportion of MS with regard to total microorganisms (%MS/TM) (p0.05) after 14 days for MS and 21 days for %MS/TM. The counts of TM and TS and the proportion of MS to total streptococci did not differ statistically from baseline (p>0.05) after chlorhexidine treatment. The results suggest that the effect of chlorhexidine gel treatment on suppression of mutans streptococci is limited to less than a month in highly colonized individuals.

  8. Fluorine profiling after application of various anti-caries gels

    Science.gov (United States)

    Zschau, H.-E.; Plier, F.; Otto, G.; Wyrwich, C.; Treide, A.

    1990-04-01

    Two newly developed caries-preventing gels were tested together with Elmex R on pre-school children over a time of 3 years. Proton-induced gamma-ray emission spectrometry (PIGE) was used to measure the fluorine profiles in milk teeth (incisors). In accordance with the clinical statement the results allow to produce a new anti-caries drug.

  9. Tolterodine Tartrate Proniosomal Gel Transdermal Delivery for Overactive Bladder

    Directory of Open Access Journals (Sweden)

    Rajan Rajabalaya

    2016-08-01

    Full Text Available The goal of this study was to formulate and evaluate side effects of transdermal delivery of proniosomal gel compared to oral tolterodine tartrate (TT for the treatment of overactive bladder (OAB. Proniosomal gels are surfactants, lipids and soy lecithin, prepared by coacervation phase separation. Formulations were analyzed for drug entrapment efficiency (EE, vesicle size, surface morphology, attenuated total reflectance Fourier transform infrared (ATR-FTIR spectroscopy, in vitro skin permeation, and in vivo effects. The EE was 44.87%–91.68% and vesicle size was 253–845 nm for Span formulations and morphology showed a loose structure. The stability and skin irritancy test were also carried out for the optimized formulations. Span formulations with cholesterol-containing formulation S1 and glyceryl distearate as well as lecithin containing S3 formulation showed higher cumulative percent of permeation such as 42% and 35%, respectively. In the in vivo salivary secretion model, S1 proniosomal gel had faster recovery, less cholinergic side effect on the salivary gland compared with that of oral TT. Histologically, bladder of rats treated with the proniosomal gel formulation S1 showed morphological improvements greater than those treated with S3. This study demonstrates the potential of proniosomal vesicles for transdermal delivery of TT to treat OAB.

  10. [GPC Fingerprint Chromatograms of Aloe vera Leaf Gel Polysaccharides].

    Science.gov (United States)

    Wang, Qiao-e; Xie, Dan; Qian, Jie; Dong, Yin-mao

    2015-10-01

    To establish the gel permeation chromatography (GPC) fingerprint chromatograms of polysaccharides in Aloe vera leaf gel from the same habitat (Beijing) and different habitats for evaluating the quality of Aloe vera leaf gel products commercially available and testing common adulterated substances. The samples were prepared by water-extraction and alcohol-precipitation method. GPC separation was performed on a Shodex SUGAR KS-805 (300 mm x 8.0 mm, 7 μm) column and a Shodex SUGAR KS-803 (300 mm x 8.0 mm, 6 μm) column at the temperature of 60 degrees C by eluting with 0.1 mol/L NaNO3 (containing 0.2 per thousand NaN) at a flow rate of 0.8 mL/min, the chromatographic effluent was detected by refractive index detector (RID) at the temperature of 50 degrees C. The common pattern of GPC fingerprint chromatograms was established and four common peaks were demarcated. The similarities of samples from the same habitat (Beijing) and different habitats were over 0.9. Taking the GPC fingerprint chromatograms for the qualified model, three commercially available aloe products were evaluated to be made of Aloe vera by the different manufacturing processes and four common adulterated substances of aloe polysaccharides were identified effectively. The method is simple and accurate with a good reproducibility, and it can be used for the identification and quality evaluation of Aloe vera leaf gel products.

  11. Electrically controllable ionic polymeric gels as adaptive optical lenses

    Science.gov (United States)

    Salehpoor, Karim; Shahinpoor, Mohsen; Mojarrad, Mehran

    1996-02-01

    Reversible change in optical properties of ionic polymeric gels, 2-acrylamido-2-methylpropane sulfonic acid (PAMPS) and polyacrylic acid plus sodium acrylate cross-linked with bisacrylamide (PAAM), under the effect of an electric field is reported. The shape of a cylindrical piece of the gel, with flat top and bottom surfaces, changed when affected by an electric field. The top surface became curved and the sense of the curvature (whether concave or convex) depended on the polarity of the applied electric field. The curvature of the surface changed from concave to convex and vice versa by changing the polarity of the electric field. By the use of an optical apparatus, focusing capability of the curved surface was verified and the focal length of the deformed gel was measured. The effect of the intensity of the applied electric field on the surface curvature and thus, on the focal length of the gel are tested. Different mechanisms are discussed; either of them or their combination may explain the surface deformation and curvature. Practical difficulties in the test procedure and the future potential of the electrically adaptive and active optical lenses are also discussed. These adaptive lenses may be considered as smart adaptive lenses for contact lens or other optical applications requiring focal point undulation.

  12. Comparison of agal gel precipitation test (AGPT) and enzyme linked ...

    African Journals Online (AJOL)

    The use of agar gel precipitation test (AGPT) and enzyme linked immunosorbent assay (ELISA) in assaying for the presence of infectious bursal disease (IBD) virus antibody in village chickens in Oyo State, Nigeria, was compared. Out of 400 sera subjected to ELISA, 360 (90%) samples where positive for IBD virus ...

  13. Preparation and properties of gel-peptide immunoadsorbents.

    Science.gov (United States)

    Chersi, A; Ruocco, E; Muratti, E

    1989-09-01

    The chemical complexity of peptides limits the choice of coupling procedures which can be used in the preparation of gel-peptide conjugates. Several immunoadsorbents have been investigated, in order to select those that permit the isolation of antipeptide antibodies in the highest yield and with optimal specific activity.

  14. Crystallization of mixed rare earth (didymium) molybdates in silica gel

    Indian Academy of Sciences (India)

    Experiments on the growth of mixed rare earth (didymium—a combination of La, Nd, Pr and Sm) molybdates in silica gel medium are reported. The optimum conditions conducive for the growth of these crystals are described and discussed. Concentration programming is reported to enhance the size of crystals by two-fold; ...

  15. Effect of gamma radiation on silica gel, (3)

    International Nuclear Information System (INIS)

    Ogura, Hajime; Nakazato, Chiyoko; Kondo, Masaharu; Sawai, Teruko; Sawai, Takeshi.

    1979-01-01

    The γ-irradiation of silica gel degassed for 24 h above 400 0 C produces visible color center (lambda sub(max) = 530 nm). The color center instantly disappears on exposure to H 2 at room temperature and irreversible adsorption of H 2 is concurrently observed. On the basis that color center is attributed to the positive hole due to substitutional impurity of Al in silica matrix, the yield of color center and H 2 adsorption have been investigated as a function of Al content in silica gel deliberatly prepared by us from silicon tetrachloride to contain Al in the range of 10 -3 -- 5w/0. Absorbance at 530 nm, A 530 , due to color center as well as the amount of H 2 adsorbed, (H 2 )sub(ads), increase with the Al content in the matrix. A 530 /(H 2 )sub(ads) is 1.0 x 10 6 (O.D. unit g/mol) in these gels. This ratio is seen almost same with two samples of gel commercially available. By assuming that 1 mol of H 2 reacts with 2 mol of positive hole, the extinction coefficient of color center at 530 nm is evaluated as 1.0 x 10 6 (g/mol.cm). (author)

  16. Conductivity behaviour of polymer gel electrolytes: Role of polymer

    Indian Academy of Sciences (India)

    Unknown

    with salicylic acid it has recently been found (Sekhon et al 2003) that the change in conductivity with polymer addition also depends upon the donor numbers of the solvent used. Solvent with high and low donor number show different conductivity behaviour in polymer gel electrolytes. On the basis of different experimental ...

  17. Flow behavior of mixed-protein incipient gels

    Science.gov (United States)

    Strong protein gel networks may result from synergistic interactions with other proteins or food materials above that achievable with a single protein alone. We determined varying flow and viscoelastic behavior of calcium caseinate (CC) or whey protein isolate (WPI) mixed with egg albumin (EA), fish...

  18. Growth and micro-topographical studies of gel grown cholesterol ...

    Indian Academy of Sciences (India)

    Cholesterol (C27H46O) is the most abundant and best-known steroid in the animal kingdom. The in vitro crystallization of this important biomaterial has been attempted by few researchers. Here we are reporting crystallization of pure cholesterol monohydrate crystals in gel medium. It is found that the morphology of the ...

  19. Intrathecal Delivery of Ketorolac Loaded In Situ Gels for Prolonged ...

    African Journals Online (AJOL)

    erosion for prolonged period of time [23]. Moreover, the method used for fabrication of alginate-based in situ gels in the present study was simple and reproducible. Only those formulations were selected that demonstrated satisfactory attributes in terms of gelling capacity in the pre-formulation studies. The initial drug release ...

  20. Gel Electrophoresis on a Budget to Dye for

    Science.gov (United States)

    Yu, Julie H.

    2010-01-01

    Gel electrophoresis is one of the most important tools used in molecular biology and has facilitated the entire field of genetic engineering by enabling the separation of nucleic acids and proteins. However, commercial electrophoresis kits can cost up to $800 for each setup, which is cost prohibitive for most classroom budgets. This article…

  1. Protein Crystal Growth in Gels and Stationary Magnetic Fields

    International Nuclear Information System (INIS)

    Moreno, A.; Quiroz-Garcia, B.; Yokaichiya, F.; Stojanoff, V.; Rudolph, P.

    2007-01-01

    Thaumatin, lysozyme, and ferritin single crystals were grown in solutions and gels without and with surrounding strong stationary magnetic fields. The crystal size, number and alignment in dependence on the induction force were analyzed. The crystal quality, like mosaicity, as function of the magnetic force is discussed by using synchrotron X-ray diffraction analysis

  2. A relationship between Gel'fand-Levitan and Marchenko kernels

    International Nuclear Information System (INIS)

    Kirst, T.; Von Geramb, H.V.; Amos, K.A.

    1989-01-01

    An integral equation which relates the output kernels of the Gel'fand-Levitan and Marchenko inverse scattering equations is specified. Structural details of this integral equation are studied when the S-matrix is a rational function, and the output kernels are separable in terms of Bessel, Hankel and Jost solutions. 4 refs

  3. Growth and micro-topographical studies of gel grown cholesterol ...

    Indian Academy of Sciences (India)

    Unknown

    The solubility of cholesterol in various sol- vents has been widely studied and reported (Bar et al. 1984; Pal and Moulik 1987). Cholesterol was crystallized from different solvents under various conditions and the effect of solvents on the crystal structure was studied. (Garti et al 1980, 1981). Gel is an ideal medium to grow.

  4. Synthesis of hydroxyapatite nanopowders by sol–gel emulsion ...

    Indian Academy of Sciences (India)

    Administrator

    volume% of surfactant (Span 80), followed by the addition of triethylamine, for gelation. The gel powders thus obtained were calcined at different temperatures up to 750°C. Characterization was done using XRD,. SEM and TEM. Pellets were made from the developed HAP powders and tested for its biocompatibility after.

  5. Carbon beam dosimetry using VIP polymer gel and MRI

    DEFF Research Database (Denmark)

    Kantemiris, I; Petrokokkinos, L; Angelopoulos, A

    2009-01-01

    VIP polymer gel dosimeter was used for Carbon ion beam dosimetry using a 150 MeV/n beam with 10 Gy plateau dose and a SOBP irradiation scheme with 5 Gy Bragg peak dose. The results show a decrease by 8 mm in the expected from Monte Carlo simulation range in water, suggesting that the dosimeter...

  6. Avoiding acidic region streaking in two-dimensional gel ...

    Indian Academy of Sciences (India)

    2014-07-21

    Jul 21, 2014 ... our procedure using whole cell protein extracts from two diverse organisms, Escherichia coli and Mycobacterium smegmatis. Our designed ... are prone to errors due to attenuated nuclease activity in strong denaturing buffer ... cycles becomes essential in order to get any meaningful profile from 2DE gels ...

  7. Preparative electrophoresis on linear polyacrylamide-agarose composite gels.

    Science.gov (United States)

    Shainoff, J R; Smejkal, G B; Mitkevich, O; DiBello, P M

    1996-01-01

    A preparative method for isolating centigram quantities of high molecular weight polypeptide chains with high resolution and recovery uses linear polyacrylamide/agarose composite (LPAC) gels as electrophoretic media from which the polypeptides can be easily extracted. The composites are prepared in a manner yielding linear copolymers of acrylamide and 1-allyloxy-2,3-propanediol within 2% agarose gels. After electrophoresis in sodium dodecyl sulfate (SDS), protein bands were rapidly visualized for excision by briefly immersing the gel in cold 0.1 M KCl which precipitates the protein-associated SDS. The gel slices are then freeze-thawed to disrupt the agarose matrix and promote syneresis of fluid upon centrifugation. The polypeptides are then separated from the polyacrylamide in the supernatant solution by precipitating with either acidic isopropanol, trichloroacetic acid, ammonium sulfate or other general protein precipitants. As determined with polypeptide chains of fibrinogen and its cross-linked derivatives, recoveries were virtually complete (95.4% +/- 2.2%), and were independent of molecular weights over the range tested (10(4) --10(6)).

  8. The single-cell gel electrophoresis assay to determine apoptosis ...

    African Journals Online (AJOL)

    The aim of the present study was to determine if the pattern of DNA fragmentation determined by the single cell gel electrophoresis assay can be used to determine apoptosis induced by siRNA in Colo 320 cells. When the frequency of appearance of apoptotic cells following was observed over a period of time, there was a ...

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

    Directory of Open Access Journals (Sweden)

    Yu-Ling Cheng

    2012-01-01

    Full Text Available 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.

  10. Analyses of laser and furnace treated sol-gel coatings

    NARCIS (Netherlands)

    De Hosson, JT; De Haas, M; Sudarshan, TS; Jeandin, M; Khor, KA

    1998-01-01

    Here we explore a new method that allows thin films to be made with almost any composition and degree of porosity by means of a combination of sol-gel and laser technology. Results are presented for furnace and laser treated TEOTI-(tetraethylorthotitanate as sol precursor) coated silicon samples.

  11. Aqueous gel formation from sodium salts of cellobiose lipids.

    Science.gov (United States)

    Imura, Tomohiro; Yamamoto, Shuhei; Yamashita, Chikako; Taira, Toshiaki; Minamikawa, Hiroyuki; Morita, Tomotake; Kitamoto, Dai

    2014-01-01

    Cellobiose lipids (CLs) are asymmetric bolaform biosurfactants, which are produced by Cryptococcus humicola JCM 10251 and have fungicidal activity. In this study, the sodium salts of CLs (CLNa) were prepared to improve aqueous solubility of the CLs, and their surface and gelation properties in aqueous solutions were examined by surface tension, rheology, and freeze-fracture transmission electron microscopy (FF-TEM) measurements. The surface tension measurements revealed that the CLNa have high surface activity: CMC1 and γCMC1 are 0.1 mg/mL and 34.7 mN/m, respectively. It was also found that the CLNa form giant micelles above their CMC, whose average size is 116.6 ± 31.9 nm. Unlike conventional surfactants, the surface tension reduced further with an increase in concentration and the aqueous solution became viscous at the minimum gelation concentration (MGC: 5.0 mg/mL). In rheological studies, the obtained gels proved to be rather soft and their sol-gel temperature was found to be approximately 50℃. FF-TEM observation of the gels showed 3D supramolecular structures with an entangled fibrous network. Since the present CLNa aqueous gels have a degree of fungicidal activity, they could be useful for novel multifunctional soft materials applicable to the food and cosmetic industries.

  12. MUCOADHESIVE GEL WITH IMMOBILIZED LYSOZYME: PREPARATION AND PROPERTIES

    Directory of Open Access Journals (Sweden)

    Dekina S. S.

    2015-08-01

    Full Text Available The study of non-covalent immobilized lysozyme, as well as physico-chemical and biochemical properties of obtained mucoadhesive gel was the aim of the research. Lysozyme activity was determined by bacteriolytic method (Micrococcus lysodeikticus cells acetone powder was a substrate. Lysozyme immobilization was conducted by the method of entrapment in gel. Enzyme carrier interaction was studied by viscometric, spectrophotometric and spectrofluorimetric methods. Mucoadhesive gel with immobilized lysozyme, possessing antiinflammatory and antimicrobial activities, was prepared. Due to immobilization, protein-polymer complex with the original enzymatic activity was formed. The product is characterized by high mucoadhesive properties, quantitative retaining of protein and bacteriolytic activity, prolonged release of the enzyme, improved biochemical characteristics (extended pH-activity profile, stability in acidic medium and during storage for 2 years, and it is perspective for further studies. The proposed method for lysozyme immobilization in the carboxymethyl cellulose sodium salt gel allows to obtain a stable, highly efficient product, with high adhesive properties for attachment to the mucous membranes, that is promising for use in biomedicine.

  13. SAXS experiments on voids in gel-spun polyethylene fibres

    NARCIS (Netherlands)

    Hoogsteen, W.; Brinke, G. ten; Pennings, A.J.

    1990-01-01

    The morphology and properties of extracted gel-spun polyethylene fibres depend on the spinning conditions. The main structures in the extracted fibre are shish-kebabs and lamellae. Equatorial small-angle X-ray scattering (SAXS) experiments show that the former structure is very porous due to the

  14. DSC experiments on gel-spun polyethylene fibers

    NARCIS (Netherlands)

    Hoogsteen, W.; Brinke, G. ten; Pennings, A.J.

    1988-01-01

    The tensile strength of gel-spun polyethylene fibers obtained after hot-drawing depends on spinning conditions such as spinning speed, spinning temperature, spinline stretching, polymer concentration, and molecular weight/molecular weight distribution. High deformation rates in the spinline result

  15. SAXS EXPERIMENTS ON GEL-SPUN POLYETHYLENE FIBERS

    NARCIS (Netherlands)

    Hoogsteen, W.; Pennings, A.J.; Brinke, G. ten

    The properties of gel-spun polyethylene fibers hot-drawn to the maximum draw ratio depend on the spinning conditions. Different spinning conditions result in two types of structure in the paraffin oil containing fibers: an isotropic lamellar structure or a shish-kebab structure. Meridional SAXS

  16. Synthesis and luminescence in sol–gel auto-combustion ...

    Indian Academy of Sciences (India)

    2017-11-14

    gel auto-combustion method calcined at 800. ◦. C for 1h. The samples are found to be well-crystallized pure orthorhombic CaSnO3 structure. Photolumi- nescence (PL) measurements indicated that the undoped sample exhibits ...

  17. Poly(vinyl alcohol) gels as photoacoustic breast phantoms revisited

    NARCIS (Netherlands)

    Xia, W.; Piras, D.; Heijblom, M.; Steenbergen, Wiendelt; van Leeuwen, Ton; Manohar, Srirang

    2011-01-01

    A popular phantom in photoacoustic imaging is poly(vinyl alcohol) (PVA) hydrogel fabricated by freezing and thawing (F–T) aqueous solutions of PVA. The material possesses acoustic and optical properties similar to those of tissue. Earlier work characterized PVA gels in small test specimens where

  18. Poly(vinyl alcohol) gels as photoacoustic breast phantoms revisited

    NARCIS (Netherlands)

    Xia, Wenfeng; Piras, Daniele; Heijblom, Michelle; Steenbergen, Wiendelt; van Leeuwen, Ton G.; Manohar, Srirang

    2011-01-01

    A popular phantom in photoacoustic imaging is poly(vinyl alcohol) (PVA) hydrogel fabricated by freezing and thawing (F-T) aqueous solutions of PVA. The material possesses acoustic and optical properties similar to those of tissue. Earlier work characterized PVA gels in small test specimens where

  19. Fluorine profiling after application of various anti-caries gels

    International Nuclear Information System (INIS)

    Zschau, H.E.; Plier, F.; Otto, G.; Wyrwich, C.; Treide, A.

    1990-01-01

    Two newly developed caries-preventing gels were tested together with Elmex on pre-school children over a time of 3 years. Proton-induced gamma-ray emission spectrometry (PIGE) was used to measure the fluorine profiles in milk teeth (incisors). In accordance with the clinical statement the results allow to produce a new anti-caries drug. (orig.)

  20. The Bioadhesive and Rheological properties of some fluconazole gels

    African Journals Online (AJOL)

    The results obtained indicate that high viscosity grade sodium carboxymethylcellulose (HV NaCMC) at 1.0 - 2% w/w concentration levels gave bioadhesive gels with viscoelastic properties which are affected by type and concentration of dye added to the formulation either as excipient or to assist in the determination of MTR.

  1. Gel-forming mucin interactome drives mucus viscoelasticity.

    Science.gov (United States)

    Demouveaux, Bastien; Gouyer, Valérie; Gottrand, Frédéric; Narita, Tetsuharu; Desseyn, Jean-Luc

    2018-02-01

    Mucus is a hydrogel that constitutes the first innate defense in all mammals. The main organic component of mucus, gel-forming mucins, forms a complex network through both reversible and irreversible interactions that drive mucus gel formation. Significant advances in the understanding of irreversible gel-forming mucins assembly have been made using recombinant protein approaches. However, little is known about the reversible interactions that may finely modulate mucus viscoelasticity, which can be characterized using rheology. This approach can be used to investigate both the nature of gel-forming mucins interactions and factors that influence hydrogel formation. This knowledge is directly relevant to the development of new drugs to modulate mucus viscoelasticity and to restore normal mucus functions in diseases such as in cystic fibrosis. The aim of the present review is to summarize the current knowledge about the relationship between the mucus protein matrix and its functions, with emphasis on mucus viscoelasticity. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Compressive yield stress of depletion gels from stationary centrifugation profiles

    Science.gov (United States)

    Lattuada, Enrico; Buzzaccaro, Stefano; Piazza, Roberto

    2018-01-01

    We have investigated the stationary sedimentation profiles of colloidal gels obtained by an arrested phase-separation process driven by depletion forces, which have been compressed either by natural gravity or by a centrifugal acceleration ranging between 6g and 2300g. Our measurements show that the gel rheological properties display a drastic change when the gel particle volume fraction exceeds a value φc , which barely depends on the strength of the interparticle attractive forces that consolidate the network. In particular, the gel compressive yield stress \\Pi(φ) , which increases as \\Pi(φ) ∼ φ4.2 for φ ≲ φc , displays a diverging behaviour for φ>φc , with an asymptotic value that is close to the random close packing value for hard spheres. The evidence we obtained suggests that φc basically coincides with the liquid (colloid-rich) branch of the metastable coexistence curve, rather than with the lower (and ϕ-dependent) values expected for an attractive glass line penetrating inside the coexistence region.

  3. Electrical conductivity measurements on gel grown KDP crystals ...

    Indian Academy of Sciences (India)

    Impurity added KDP crystals; gel method; electrical conductivity; activation energy. 1. Introduction. Potassium dihydrogen ... phate [(NH4)2SO4] along with double distilled water and ethyl alcohol were used. KDP was added with .... in the vicinity of electrodes or chemical changes in layers close to electrodes (Bunget and ...

  4. Neutron detector based on lithiated sol-gel glass

    CERN Document Server

    Wallace, S; Miller, L F; Dai, S

    2002-01-01

    A neutron detector technology is demonstrated based on sup 6 Li/ sup 1 sup 0 B doped sol-gel glass. The detector is a sol-gel glass film coated silicon surface barrier detector (SBD). The ionized charged particles from (n, alpha) reactions in the sol-gel film enter the SBD and are counted. Data showing that gamma-ray pulse amplitudes interfere with identifying charged particles that exit the film layer with energies below the gamma-ray energy is presented. Experiments were performed showing the effect of sup 1 sup 3 sup 7 Cs and sup 6 sup 0 Co gamma rays on the SBD detector. The reaction product energies of the triton and alpha particles from sup 6 Li are significantly greater than the energies of the Compton electrons from high-energy gamma rays, allowing the measurement of neutrons in a high gamma background. The sol-gel radiation detection technology may be applicable to the characterization of transuranic waste, spent nuclear fuel and to the monitoring of stored plutonium.

  5. Evaluation and Selection of Gel Base for the Formulation of ...

    African Journals Online (AJOL)

    Purpose: To formulate dexpanthenol gels with enhanced in vivo absorption properties via skin. Methods: Carboxyvinyl derivatives (Carbopol 980 and Ultrez 10) and poloxamer (Lutrol F 127) were used as the hydrogel base in the formulations. Changes in rheological properties (apparent viscosity and penetration values) ...

  6. Effects of a traditional chinese medicine based desensitizing gel on ...

    African Journals Online (AJOL)

    Background and Objective: Bamboo salt, Calcined oyster, Drynaria fortunei, Indigo naturalis and Rehmannia glutinosa have been the main ingredients of many formulations in Chinese medicine for the treatment of toothache. This study evaluated the effect of a new desensitizing gel on dentin hypersensitivity (DH). Materials ...

  7. Evaluation of denaturing gradient gel electrophoresis (DGGE) used ...

    African Journals Online (AJOL)

    Denaturing gradient gel electrophoresis (DGGE) is a powerful method used to study structure of bacterial communities, without cultivation, based on the diversity of the genes coding for ribosomal RNA. However, the results are strongly dependent on the respective target region of the used primer systems. Therefore, three ...

  8. Silver and Cyanine Staining of Oligonucleotides in Polyacrylamide Gel.

    Science.gov (United States)

    Tang, Weizhong; Zhou, Huafu; Li, Wei

    2015-01-01

    To explore why some oligonucleotides in denaturing polyacrylamide gel could not be silver-stained, 134 different oligonucleotides were analyzed using denaturing polyacrylamide gel electrophoresis stained with silver and asymmetric cyanine. As a result, we found that the sensitivity of oligos (dA), (dC), (dG) and (dT) to silver staining could be ranged as (dA) > (dG) > (dC) > (dT) from high to low. It was unexpected that oligo (dT) was hard to be silver-stained. Moreover, the silver staining of an oligonucleotide containing base T could be partially or completely inhibited by base T. The inhibition of silver staining by base T was a competitive inhibition which could be affected by the amounts of the argyrophil nucleobase and base T, the cis-distance between the argyrophil nucleobase and base T, and the gel concentration. The changes of the intensity of an oligonucleotide band caused by the changes of DNA base composition were diverse and interesting. The intensity of some oligonucleotide bands would significantly change when the changes of DNA base composition accumulated to a certain extent (usually ≥ 4 nt). The sensitivity of cyanine staining of ≤ 11-nt long oligonucleotides could be enhanced about 250-fold by fixing the gels with methanol fixing solution.

  9. Two-dimensional gel electrophoresis analysis of different parts of ...

    African Journals Online (AJOL)

    Two-dimensional gel electrophoresis analysis of different parts of Panax quinquefolius L. root. ... From these results it was concluded that proteomic analysis method was an effective way to identify the different parts of quinquefolius L. root. These findings may contribute to further understanding of the physiological ...

  10. Assessment of Native Agar Gels Extracted from Gracilaria debilis ...

    African Journals Online (AJOL)

    Native agar gels extracted from Gracilaria debilis and G. salicornia harvested during the rainy and dry seasons, were assessed for culturing the microorganisms Micrococcus luteus, Saccharomyces cerevisiae and Pleurotus flabellatus. Agars extracted from plants harvested during the rainy season were suitable for culturing ...

  11. Growth and characterization of gel grown pure and mixed iron ...

    Indian Academy of Sciences (India)

    Several applications of iron tartrate and manganese tartrate compounds are reported in the literature. In the present investigation, we have grown pure and mixed iron (II)–manganese levo-tartrate crystals by single diffusion gel growth technique. Crystals with spherulitic morphology were harvested. The colouration of the ...

  12. Growth of strontium oxalate crystals in agar–agar gel

    Indian Academy of Sciences (India)

    single diffusion technique in which the gel medium does. Figure 4. a. Transparent prismatic bi-pyramidal platy shaped crystals at interstitial and spherulite crystals well inside test-tube using NH4Cl additive in single diffusion and b. some good quality crystals obtained using NH4Cl as addictive in single diffusion.

  13. Synchrotron Radiation Pair Distribution Function Analysis of Gels in Cements

    Directory of Open Access Journals (Sweden)

    Ana Cuesta

    2017-10-01

    Full Text Available The analysis of atomic ordering in a nanocrystalline phase with small particle sizes, below 5 nm, is intrinsically complicated because of the lack of long-range order. Furthermore, the presence of additional crystalline phase(s may exacerbate the problem, as is the case in cement pastes. Here, we use the synchrotron pair distribution function (PDF chiefly to characterize the local atomic order of the nanocrystalline phases, gels, in cement pastes. We have used a multi r-range analysis approach, where the ~4–7 nm r-range allows determining the crystalline phase contents; the ~1–2.5 nm r-range is used to characterize the atomic ordering in the nanocrystalline component; and the ~0.2–1.0 nm r-range gives insights about additional amorphous components. Specifically, we have prepared four alite pastes with variable water contents, and the analyses showed that a defective tobermorite, Ca11Si9O28(OH2.8.5H2O, gave the best fit. Furthermore, the PDF analyses suggest that the calcium silicate hydrate gel is composed of this tobermorite and amorphous calcium hydroxide. Finally, this approach has been used to study alternative cements. The hydration of monocalcium aluminate and ye’elimite pastes yield aluminum hydroxide gels. PDF analyses show that these gels are constituted of nanocrystalline gibbsite, and the particle size can be as small as 2.5 nm.

  14. Preliminary study of diffusion effects in Fricke gel dosimeters

    International Nuclear Information System (INIS)

    Quiroga, A.; Vedelago, J.; Valente, M.

    2014-08-01

    Diffusion of ferric ions in ferrous sulfate (Fricke) gels represents one of the main drawbacks of some radiation detectors, like Fricke gel dosimeters. In practice, this disadvantage can be overcome by prompt dosimeter analysis, constraining strongly the time between irradiation and analysis. Due to required integral accuracy levels, special dedicated protocols are implemented with the aim of minimizing signal blurring due to diffusion effects. This work presents dedicated analytic modelling and numerical calculations of diffusion coefficients in Fricke gel radiation sensitive material. Samples are optically analysed by means of visible light transmission measurements capturing images with a Ccd camera provided with a monochromatic 585 nm filter corresponding to the X O-infused Fricke solution absorbance peak. Dose distributions in Fricke gels are suitably delivered in order to assess specific initial conditions further studied by periodical sample image acquisitions. In a first analytic approach, experimental data are fit with linear models in order to achieve a value for the diffusion coefficient. The second approach to the problem consists on a group of computational algorithms based on inverse problem formulation, along with suitable 2D diffusion model capable of estimating diffusion coefficients by fitting the obtained algorithm numerical solutions with the corresponding experimental data. Comparisons are performed by introducing an appropriate functional in order to analyse both experimental and numerical values. Solutions to second order diffusion equation are calculated in the framework of a dedicated method that incorporates Finite Element Method. Moreover, optimised solutions can be attained by gradient type minimisation algorithms. Knowledge about diffusion coefficient for Fricke gel radiation detector might be helpful in accounting for effects regarding elapsed time between dosimeter irradiation and further analysis. Hence, corrections might be included

  15. Preliminary study of diffusion effects in Fricke gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Quiroga, A. [Centro de Investigacion y Estudios de Matematica de Cordoba, Oficina 318 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina); Vedelago, J. [Laboratorio de Investigaciones e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Laboratorio 448 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina); Valente, M., E-mail: aiquiroga@famaf.unc.edu [Instituto de Fisica Enrique Gaviola, Oficina 102 FaMAF - UNC, Av. Luis Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2014-08-15

    Diffusion of ferric ions in ferrous sulfate (Fricke) gels represents one of the main drawbacks of some radiation detectors, like Fricke gel dosimeters. In practice, this disadvantage can be overcome by prompt dosimeter analysis, constraining strongly the time between irradiation and analysis. Due to required integral accuracy levels, special dedicated protocols are implemented with the aim of minimizing signal blurring due to diffusion effects. This work presents dedicated analytic modelling and numerical calculations of diffusion coefficients in Fricke gel radiation sensitive material. Samples are optically analysed by means of visible light transmission measurements capturing images with a Ccd camera provided with a monochromatic 585 nm filter corresponding to the X O-infused Fricke solution absorbance peak. Dose distributions in Fricke gels are suitably delivered in order to assess specific initial conditions further studied by periodical sample image acquisitions. In a first analytic approach, experimental data are fit with linear models in order to achieve a value for the diffusion coefficient. The second approach to the problem consists on a group of computational algorithms based on inverse problem formulation, along with suitable 2D diffusion model capable of estimating diffusion coefficients by fitting the obtained algorithm numerical solutions with the corresponding experimental data. Comparisons are performed by introducing an appropriate functional in order to analyse both experimental and numerical values. Solutions to second order diffusion equation are calculated in the framework of a dedicated method that incorporates Finite Element Method. Moreover, optimised solutions can be attained by gradient type minimisation algorithms. Knowledge about diffusion coefficient for Fricke gel radiation detector might be helpful in accounting for effects regarding elapsed time between dosimeter irradiation and further analysis. Hence, corrections might be included

  16. Saos-2 cell-mediated mineralization on collagen gels: Effect of densification and bioglass incorporation.

    Science.gov (United States)

    Liu, Gengbo; Pastakia, Meet; Fenn, Michael B; Kishore, Vipuil

    2016-05-01

    Plastic compression is a collagen densification process that has been widely used for the development of mechanically robust collagen-based materials. Incorporation of bioglass within plastically compressed collagen gels has been shown to mimic the microstructural properties of native bone and enhance in vitro cell-mediated mineralization. The current study seeks to decouple the effects of collagen densification and bioglass incorporation to understand the interplay between collagen packing density and presence of bioglass on cell-mediated mineralization. Saos-2 cell-mediated mineralization was assessed as a measure of the osteoconductivity of four different collagen gels: (1) uncompressed collagen gel (UC), (2) bioglass incorporated uncompressed collagen gel (UC + BG), (3) plastically compressed collagen gel (PC), and (4) bioglass incorporated plastically compressed collagen gel (PC + BG). The results indicated that collagen densification enhanced mineralization as shown by SEM, increased alkaline phosphatase activity and produced significantly higher amounts of mineralized nodules on PC gels compared to UC gels. Further, the amount of nodule formation on PC gels was significantly higher compared to UC + BG gels indicating that increase in matrix stiffness due to collagen densification had a greater effect on cell-mediated mineralization compared to bioglass incorporation into loosely packed UC gels. Incorporation of bioglass into PC gels further enhanced mineralization as evidenced by significantly larger nodule size and higher amount of mineralization on PC + BG gels compared to PC gels. In conclusion, collagen densification via plastic compression improves the osteoconductivity of collagen gels. Further, incorporation of bioglass within PC gels has an additive effect and further enhances the osteoconductivity of collagen gels. © 2016 Wiley Periodicals, Inc.

  17. Antibacterial Inhibitory Effects of Punica Granatum Gel on Cariogenic Bacteria: An in vitro Study.

    Science.gov (United States)

    Millo, Grazielle; Juntavee, Apa; Ratanathongkam, Ariya; Nualkaew, Natsajee; Peerapattana, Jomjai; Chatchiwiwattana, Supaporn

    2017-01-01

    This study evaluated the in vitro antibacterial effects of the formulated Punica granatum (PG) gel against Streptococcus mutans, Streptococcus sanguinis, and Lactobacillus casei. The PG extract was dissolved in water at 500 mg/mL. High performance liquid chromatography (HPLC) was used for identification and quantification of chemical marker punicalagin. Minimum bactericidal concentration (MBC) and time-kill assay (TKA) were investigated. Antibacterial activities of the formulated PG gel, 2% chlorhexidine (CHX) gel and blank gel were tested by measuring the zones of inhibition through agar well diffusion method. The HPLC results showed presence of punicalagin at 2023.58 ± 25.29 pg/mL in the aqueous PG extract and at 0.234% (w/w) in the formulated PG gel. The MBC for S. mutans, S. Sanguinis, and L. casei were 250, 125, and 500 mg/mL respectively. The TKA of 500 mg/mL aqueous PG extract showed total inhibition of S. mutans, S. Sanguinis, and L. casei at 6, 1, and 24 hours contact time respectively. Agar well diffusion revealed that for S. mutans, CHX gel > PG gel > blank gel; for S. sanguinis, CHX gel = PG gel > blank gel; for L. casei, CHX gel > PG gel = blank gel. Comparison of the PG gel potency showed that S. sanguinis = S. mutans > L. casei. The PG gel equivalent to 0.234% punicalagin (w/w) inhibited S. mutans and S. sanguinis but not L. casei within 24 hours incubation period and has the potential to be used for caries prevention. Millo G, Juntavee A, Ratanathongkam A, Nualkaew N, Peerapattana J, Chatchiwiwattana S. Antibacterial Inhibitory Effects of Punica Granatum Gel on Cariogenic Bacteria: An in vitro Study. Int J Clin Pediatr Dent 2017;10(2):152-157.

  18. Successful mouse hepatocyte culture with sandwich collagen gel formation

    Science.gov (United States)

    Choi, Hyun Jung

    2013-01-01

    Purpose Primary mammalian hepatocytes largely retain their liver-specific functions when they are freshly derived from donors. However, long-term cultures of functional hepatocytes are difficult to establish. To increase the longevity and maintain the differentiated functions of hepatocytes in primary culture, cells can be cultured in a sandwich configuration of collagen. In such a configuration, hepatocytes can be cultured for longer periods compared with cultures on single layers of collagen. However, research regarding mouse hepatocytes in sandwich culture is lacking. Methods Primary mouse hepatocytes were sandwiched between two layers of collagen to maintain the stability of their liver-specific functions. After gelation, 2 mL of hepatocyte culture medium was applied. Results After 24 hours, 5, 10 days of culture, the collagen gel sandwich maintained the cellular border and numbers of bile canaliculi more efficiently than a single collagen coating in both high and low density culture dishes. Reverse transcription-polymerase chain reaction analysis of alpha-1-antitrypsin (AAT), hepatocyte nuclear factor 4 alpha (HNF4A), alphafetoprotein, albumin, tryptophan oxygenase (TO), the tyrosine aminotransferase gene, glucose-6-phosphatase, glyceraldehyde-3-phosphate dehydrogenase for mouse primary hepatocytes cultured on collagen coated dishes and collagen gels showed superior hepatocyte-related gene expression in cells grown using the collagen gel sandwich culture system. AAT, HNF4A, albumin, TO were found to be expressed in mouse hepatocytes cultured on collagen gels for 5 and 10 days. In contrast, mouse hepatocytes grown on collagen-coated dishes did not express these genes after 5 and 10 days of culture. Conclusion The collagen gel sandwich method is suitable for primary culture system of adult mouse hepatocytes. PMID:23577314

  19. Platelets stimulate fibroblast-mediated contraction of collagen gels

    Directory of Open Access Journals (Sweden)

    Lundahl Joachim

    2003-10-01

    Full Text Available Abstract Background Platelets are thought to play a role in a variety of inflammatory conditions in the lung, some of which may lead to fibrosis. In the current study we tested the hypothesis that whole platelets and platelet lysate can mediate remodelling of extracellular matrix in vitro by affecting fibroblast-mediated contraction of a collagen gel. We also sought to determine to what extent platelet-derived growth factor (PDGF and transforming growth factor-β (TGF-β contribute to this effect. Methods Washed platelets, isolated from healthy blood donors, and platelet lysate (freezing and thawing, were cast together with human lung fibroblasts in three-dimensional collagen gels. The gels were then released and cultured for four days. PDGF and TGF-β1 concentrations were measured in culture supernatants by ELISA. Results Both platelets and platelet lysate augmented fibroblast-mediated gel contraction in a time and concentration dependent manner (19.9% ± 0.1 (mean ± SEM of initial area vs. 48.0% ± 0.4 at 48 hours; P 1 and PDGF-AA/AB were released in co-culture. PDGF-AA/AB had a maximum release at 24 hours whereas TGF-β1 release increased with longer culture periods. Neutralising antibodies to these mediators partially inhibited platelet-induced gel contraction. Conclusion We conclude that platelets may promote remodelling of extracellular matrix in vitro and that PDGF and TGF-β partially mediate this effect, also indicating a role for other mediators. The findings may be an important mechanism in regulating repair processes after injury.

  20. Local environment of zirconium in nuclear gels studied by XAS

    International Nuclear Information System (INIS)

    Pelegrin, E.; Ildefonse, Ph.; Calas, G.; Ricol, St.; Flank, A.M.

    1997-01-01

    During lixiviation experiments, nuclear gels are formed and heavy metals are retained. In order to understand this retardation mechanisms, we performed an analysis of the local environment of Zr in parent glasses and derived alteration gels both at the Zr-L II,III , and Zr-K edges. Calibration of the method was conducted through the analysis of model compounds with known coordination number (CN): catapleite Na 2 ZrSi 3 O 9 ,2H 2 O (CN=6), baddeleyite ZrO 2 (CN=7) and zircon SiZrO 4 (CN=8). Nuclear glasses (R7T7, and a simplified nuclear glass V 1) and gels obtained at 90 deg C, with leaching times from 7 to 12 months and with solution renewal. were also investigated (GR7T7R and GV1). Zr-L II,III XANES spectra evidenced that zirconium is 6-fold coordinated in R7T7 and V1 nuclear glasses. For GR7T7R and GV1 gels, Zr local environment is significantly changed, and a mixture of CN (6 and 7J has been evidenced. Quantitative structural results were derived from EXAFS analysis at Zr-K edge. In parent glasses, derived Zr-O distance is 2.10±0.01 10 -10 m, and is in the range Zr-O distances for octahedral coordination in model compounds. In both gels studied, Zr-O distances increase significantly up to 2.15 ±0.01 10 -10 m. This distance is close to that known in baddeleyite (2,158 10 -10 m). A better understanding of the Zr retention mechanism has to be made by studying the second neighbors contributions. (authors)

  1. Characterisation of a new alkoxide sol-gel hydroxyapatite

    International Nuclear Information System (INIS)

    Green, D.D.; Kannangara, G.S.K.; Milev, A.; Ben-Nissan, B.

    1999-01-01

    Hydroxyapatite (HAp) coatings have been used to promote bone growth and fixation towards implant surfaces to encourage faster recovery times for the recipient. Current coating processing techniques, capable of producing thin HAp layers are pulsed-laser deposition and sputtering (high-temperature processing). Other technologies are in vitro methods, electrodeposition and sol-gel, due to the fact that these techniques utilise lower processing temperatures they avoid structural instabilities of HAp at elevated temperatures. The term sol-gel encompasses any process of producing ceramic materials (single and mixed oxides, as well as non-oxides e.g. nitrides) from solutions. The sol-gel process was first identified by Ebelman, and has been used to produce ceramic powders, coatings, and bulk materials including glasses. The implementation of a sol-gel methodology enables increased stoichiometry and homogeneity, while having the ability to coat complex shapes. Sol-gel hydroxyapatite reported by Chai et al. employed tri ethyl phosphite [ P(OEt) 3 ] as the staring phosphorus alkoxide precursor, whereby it was established that in order to obtain monophasic hydroxyapatite upon firing there must be a 24 hour ripening period. The ripening period was determined to be an equilibrium step whereby the equilibrium intermediate phase lied in favour of a diethyl phosphite arrangement (species) within the sol. Therefore, the work here under taken was to produce hydroxyapatite using diethyl phosphite [HOP(OEt) 2 ] as a starting alkoxide precursor with a final aim to reduce or eliminate the ageing period as observed by Chai et al in P(OEt) 3 solutions

  2. Comparative study on the effects of negatively-charged biopolymers on chitosan-based gels for the development of instantaneous gels

    International Nuclear Information System (INIS)

    Jimeno, Austin Ed B.; Chakraborty, Soma

    2015-01-01

    Polymeric electrolytic complexes are solutions of charged/ionized chains. These solutions of positive and negative charge can be combined to make instantaneous networks bonded by electrostatic interactions, a gel network. These electrostatic interaction allows for easy application in injectable gels as the network can be temporarily distributed with the application of force and reformed on the relief of it. Possible applications for these injectable gels include drug delivery and wound-healing. κ-Carrageenan, dextran sulfate, alginate, and chitosan are polyelectrolytic biocompatible polymers which are widely studied and used for a variety of biomedical applications. Gel networks are made by combining a negatively-charged (κ-Carrageenan, dextran sulfate, or alginate) and positively charged (chitosan) solutions. The strong electrostatic interaction between the opposite charges from the gel network and the inherent biocompatibility of the polymers allow future biomedical applications. Quat 188-modified chitosan has additional sites for electrostatic bonding, can be dissolved in neutral, basic, and acidic pH, and has shown inherent antibacterial activity. The objectives of this study are the following: to formulate chitosan-based gels mixing solutions of chitosan with solutions of either κ-Carrageenan, dextran sulfate, or alginate, study the gelation of the gels as function of time and pH (4, 7, and 9) using UV-Vis, characterize the chitosan-based gels through DSC and DMA, characterize the physiological degradation of the chitosan-based gels, and compare results with those from Quat 188-modified chitosan-based gels. Polyelectrolytic solutions of chitosan and negatively-charged biopolymer of similar viscosities were mixed. It was determined from the UV-Vis spectroscopy of the chitosan-carrageenan gels under pH7 buffer that the increase of concentration by a factor of 5 for 0.006M-0.0095M and 1.25 for 0.0095M-0.0150M Chitosan-Carrageenan gels improved gelation by the

  3. Purification of Peptide Components including Melittin from Bee Venom using gel filtration chromatography and propionic acid/urea polyacrylamide gel electrophoresis

    Directory of Open Access Journals (Sweden)

    Young Chon Choi

    2006-06-01

    Full Text Available Objectives : This study was conducted to carry out Purification of Melittin and other peptide components from Bee Venom using gel filtration chromatography and propionic acid/urea polyacrylamide gel electrophoresis Methods : Melittin and other peptide components were separated from bee venom by using gel filtration chromatography on Sephadex G-50 column in 0.05M ammonium acetate buffer. Results : Melittin and other peptide components were separated from bee venom by using gel filtration chromatography on Sephadex G-50 column in 0.05M ammonium acetate buffer. The fractions obtained from gel filtration chromatography was analyzed by using SDS-PAGE and propionic acid/urea polyacrylamide gel electrophoresis. The melittin obtained from the gel filtration contained residual amount of phospholipase A2 and a protein with molecular weight of 6,000. The contaminating proteins were removed by the second gel filtration chromatography. Conclusion : Gel filtration chromatography and propionic acid/urea polyacrylamide gel electrophoresis are useful to separate peptide components including melittin from bee venom.

  4. Identifying Gel-Separated Proteins Using In-Gel Digestion, Mass Spectrometry, and Database Searching: Consider the Chemistry

    Science.gov (United States)

    Albright, Jessica C.; Dassenko, David J.; Mohamed, Essa A.; Beussman, Douglas J.

    2009-01-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is an important bioanalytical technique in drug discovery, proteomics, and research at the biology-chemistry interface. This is an especially powerful tool when combined with gel separation of proteins and database mining using the mass spectral data. Currently, few hands-on…

  5. Immobilization of chitosan gel with cross-linking reagent on PNIPAAm gel/PP nonwoven composites surface

    International Nuclear Information System (INIS)

    Chen, K.-S.; Ku, Y.-A.; Lee, C.-H.; Lin, H.-R.; Lin, F.-H.; Chen, T.-M.

    2005-01-01

    This study was to immobilize chitosan (CS), which is a biodegradable and antibacterial polymer, on poly(N-isopropylacrylamide) (PNIPAAm) gel/polypropylene (PP) nonwoven composites surface for wound dressing applications. PP nonwoven has been extensively used due to its porosity, allowing ventilation, high surface area and excellent mechanical properties. However, the hydrophobic surface of PP nonwoven limits its applications; in this study, we used the plasma-activation treatment and subsequently UV-light graft polymerization of NIPAAm gel to improve its hydrophilicity. Chitosan was immobilized onto PNIPAAm gel/PP nonwoven composites surface using the cross-linking agent, glutaraldehyde (GA). This complex was characterized by scanning electron microscopy (SEM). The results indicated that the wettability of the composite was improved after plasma treatment and photo-induced graft polymerization and chitosan was successfully immobilized onto the surface of PNIPAAm gel/PP nonwoven composites through cross-linking process. Finally, the preliminary result shows that chitosan hydrogels displayed antibacterial ability to Escherichia coli and Staphylococcus aureus. The (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) (MTT) method indicated that the porous chitosan sponge exhibited good biocompatibility to fibroblast cells

  6. Selecting and Effectively Using Sports Drinks, Carbohydrate Gels and Energy Bars

    Science.gov (United States)

    ... and Effectively Using Sports Drinks, Carbohydrate Gels and Energy Bars Depending upon the length of your workout ... can hinder performance. Sports drinks, carbohydrate gels and energy bars can help restore your body’s fluids and ...

  7. Understanding Alginate Gel Development for Bioclogging and Biogeophysical Experiments

    Science.gov (United States)

    Brown, I.; Atekwana, E. A.; Abdel Aal, G. Z.; Atekwana, E. A.; Sarkisova, S.; Patrauchan, M.

    2012-12-01

    Bioremediation strategies to mitigate the transport of heavy metals and radionuclides in subsurface sediments have largely targeted to increase the mobility and/or solubility of these compounds by the stimulation of biogeochemical activity of the metal- and sulfate-reducing bacteria. The latter secrete and/or release out diverse biochemical molecule including, first of all, organic acids and biopolymers such as alginic acid, proteins and DNA. Alginate gel is one of the major components determining the structure of biofilm which causes clogging in porous media. Biopolymers composing biofilm having, at least, two main functions: to be a scaffold for a microbial biofilm, and to regulate the exchange of metabolites and ions between an environment and bacterial cells. Additionally, the accumulation of biopolymers and a matured biofilm within porous media was shown to contribute to a detectable biogeophysical signal, spectral induced polarization (SIP), in particular. Our objective is to understand the role of different biofilm components on the SIP response as the latter has been proposed as a non-invasive tool to monitor biofilm development and rate of clogging in the subsurface. Understanding the process of alginate gel development may aid in the understanding of the fate and transport of mineralized heavy metals and radionuclides in contaminated soils. Here we describe the reciprocal relationship between environmental chemistry and alginate gel development. Commercial (Sigma) alginic acid (AA) was used as a substratum for the preparation of a model gel. AA was solubilized by adjusting solutions with pH up to 4 with 0.1 NaOH. Both Ca(OH)2 or CaCl2 were used to initiate the gelation of alginate. pH, fluid conductivity, soluble Ca2+ concentration, and a yield of gelated alginate were monitored in both liquid and porous media after the interaction of calcium compounds with alginate. This study confirms the critical role of Ca2+ for alginate gelation, biofilm development

  8. Functional Nanofibers and Colloidal Gels: Key Elements to Enhance Functionality

    Science.gov (United States)

    Vogel, Nancy Amanda

    material so that prolonged release can be readily achieved from highly water soluble nanofibers. The final research theme focuses on gaining a fundamental understanding of a new class of materials, nanodiamond, so that a desired microstructure can be achieved via functionalization or manipulating processing parameters. In particular, we utilize both steady and dynamic rheology techniques to systematically investigate systems of nanodiamonds dispersed in model nonpolar (mineral oil) and polar (glycerol) media. In both cases, selfsupporting colloidal gels form at relatively low nanodiamond content; however, the gel behavior is highly dependent on the type of media used. Nanodiamonds dispersed in mineral oil exhibit characteristic colloidal gel behavior, with a rheological response that is independent of both frequency and time. However, nanodiamonds dispersed in glycerol exhibit a time dependent response, with the strength of the colloidal gels increasing several orders of magnitude. We attribute these rheological differences to changes in solvent complexity, where new particle-solvent and particle-particle interactions have the potential to delay optimal gel formation. In addition to colloidal gel formation, we use large oscillatory strains to probe the effect of processing parameters on microstructure disruption and recovery. The results indicate that the formation and rearrangement of the nanodiamond microstructures are concentration dependent for both media types; however, the recovery after breakdown is different for each system. Recovery of the nanodiamond/mineral oil gels is incomplete, with the strength of the recovered gel being significantly reduced. In contrast, the original strength of the nanodiamond/glycerol gels is recoverable as the system restructures with time. The practical implications of these results are significant as it suggest that shear history and solvent polarity play a dominant role in nanodiamond processing.

  9. Adhesive and structural properties of thermoreversible polyacrylate gels

    Science.gov (United States)

    Flanigan, Cynthia Mowery

    Methods for quantifying very weak adhesive interactions between two bodies in contact have been developed using a low-modulus material in conjunction with a linear elastic fracture mechanics analysis based on the treatment of Johnson, Kendall and Roberts (JKR). Using this approach, axisymmetric adhesion tests have been performed on polyacrylate gel lenses and thin layers, in contact with well-characterized surfaces. These thermally reversible gels were formed by diluting a triblock copolymer with poly(methyl methacrylate) (PMMA) endblocks and a poly(n-butyl acrylate) midblock with a selective solvent for the center block. Rheological studies on this swollen copolymer indicate that the material is completely elastic at room temperature and undergoes a rapid, thermally reversible gelation, thus making it an excellent model system to probe the adhesive properties of soft materials. Adhesive and frictional properties of thin, elastic layers in contact with a glass, hemispherical indenter have been investigated. Studies on these highly compliant gels highlight the significance of finite size corrections to the compliance and displacement between the two contacting bodies. For situations where the applied load is too low to measure experimentally, expressions for G /E, the energy release rate normalized by Young's modulus, are shown to provide an accurate means to quantify adhesion with these low-moduli materials. Small angle X-ray scattering experiments in conjunction with rheological tests have shown that changes in composition and temperature affect the elastic nature of the gel. In addition, an equilibrium gelation process is utilized to produce "dried" polymer layers with reproducible adhesive properties. With this method, acrylic acid moieties have been shown to enhance the adhesive performance of these materials without influencing their structure. Lastly, the development of elastic instabilities within confined gel layers has been examined. The aspect ratio of

  10. Swelling, stiffness, and stress in gel material - as related to moisture sorption

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    1996-01-01

    A method is presented by which estimates can be made on swelling, bulk modulus, and internal stresses in gel materials as related to water sorption. Porous gel materials are considered as gel materials made porous by capillary pores large enough not to create capillary condensation and capillary...

  11. Using sol-gel component as additive to foundry coatings to improve casting quality

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Poulsen, T.; Gravesen, B.

    2012-01-01

    was evaluated. The results show that the surface quality of castings obtained by adding the sol‐gel component to the coatings for cold box cores has no significant difference from castings produced with coatings without sol‐gel component. On the other hand, the addition of the sol‐gel component in coatings...

  12. Growth and study of some gel grown group II single crystals of iodate

    Indian Academy of Sciences (India)

    Unknown

    The effect of doping was studied using IR spectroscopy and thermal analysis. Keywords. Silica gel; barium iodate; calcium iodate; XRD; FT-IR; TGA/DTA. 1. .... Table 2. Effect of concentration of reactants on habit quality and size of BaIO3 crystals. Conc. of reactant in gel. Conc. of reactant above gel. Habit. Quality. Size. (mm).

  13. Structure and rheological properties of acid-induced egg white protein gels

    NARCIS (Netherlands)

    Weijers, M.; Velde, F. van de; Stijnman, A.; Pijpekamp, A. van de; Visschers, R.W.

    2006-01-01

    This study compares the rheological properties of acid-induced gels prepared of industrial spray-dried egg white proteins (EWP) with the acid-induced gels prepared of ovalbumin (OA) and whey protein isolate (WPI). Also we aimed to form transparent gels of EWP by means of the cold-gelation process.

  14. X-ray computer tomography, ultrasound and vibrational spectroscopic evaluation techniques of polymer gel dosimeters

    International Nuclear Information System (INIS)

    Baldock, Clive

    2004-01-01

    Since Gore et al published their paper on Fricke gel dosimetry, the predominant method of evaluation of both Fricke and polymer gel dosimeters has been magnetic resonance imaging (MRI). More recently optical computer tomography (CT) has also been a favourable evaluation method. Other techniques have been explored and developed as potential evaluation techniques in gel dosimetry. This paper reviews these other developments

  15. 21 CFR 878.3540 - Silicone gel-filled breast prosthesis.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Silicone gel-filled breast prosthesis. 878.3540...-filled breast prosthesis. (a) Identification—(1) Single-lumen silicone gel-filled breast prosthesis. A single-lumen silicone gel-filled breast prosthesis is a silicone rubber shell made of polysiloxane(s...

  16. 40 CFR 721.9680 - Alkaline titania silica gel (generic name).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkaline titania silica gel (generic... Specific Chemical Substances § 721.9680 Alkaline titania silica gel (generic name). (a) Chemical substance... alkaline titania silica gel (PMN P-95-529) is subject to reporting under this section for the significant...

  17. Effect of nightguard vital bleaching gel on the color stability of provisional restorative materials

    Directory of Open Access Journals (Sweden)

    Salwa Omar Bajunaid

    2016-01-01

    Conclusions: Composite-based provisional material showed highest color stability when exposed to vital tooth bleaching gel, whereas methacrylate-based material was the least color stable. Polycarbonate crowns were more color stable when exposed to 15% bleaching gel as opposed to 10% bleaching gel.

  18. Rheological properties and mechanical stability of new gel-entrapment systems applied in bioreactors

    NARCIS (Netherlands)

    Vogelsang, C.; Wijffels, R.H.; Ostgaard, K.

    2000-01-01

    The mechanical stability of gels applied for entrapment and retention of biocatalysts in bioreactors is of crucial importance for successful scale-up applications. Gel abrasion in agitated reactors will depend on liquid shear, bubble shear, and wall shear, as well as collisions between the gel

  19. In vivo compatibility and degradation of crosslinked gelatin gels incorporated in knitted Dacron

    NARCIS (Netherlands)

    Kuijpers, A. J.; van Wachem, P. B.; van Luyn, M. J.; Plantinga, J. A.; Engbers, G. H.; Krijgsveld, J.; Zaat, S. A.; Dankert, J.; Feijen, J.

    2000-01-01

    Gelatin gels were applied to porous Dacron meshes with the aim of using these gels for local drug delivery. In this article, the biocompatibility and degradation of gelatin gels with different crosslink densities applied in Dacron were studied in vivo by subcutaneous implantation in rats. Dacron

  20. In vivo compatibility and degradation of cross-linked gelatin gels incorporated in knitted Dacron

    NARCIS (Netherlands)

    Kuijpers, A.J.; van Wachem, P.B.; van Luyn, M.J.A.; Plantinga, J.A.; Engbers, G.H.M.; Krijgsveld, J.; Zaat, S.A.J.; Dankert, J.; Feijen, Jan

    2000-01-01

    Gelatin gels were applied to porous Dacron meshes with the aim of using these gels for local drug delivery. In this article, the biocompatibility and degradation of gelatin gels with different crosslink densities applied in Dacron were studied in vivo by subcutaneous implantation in rats. Dacron

  1. In vivo compatibility and degradation of crosslinked gelatin gels incorporated in knitted Dacron

    NARCIS (Netherlands)

    Kuijpers, AJ; van Wachem, PB; van Luyn, MJA; Plantinga, JA; Engbers, GHM; Krijgsveld, J; Zaat, SAJ; Feijen, J

    Gelatin gels were applied to porous Dacron meshes with the aim of using these gels for local drug delivery. in this article, the biocompatibility and degradation of gelatin gels with different crosslink densities applied in Dacron were studied in vivo by subcutaneous implantation in rats. Dacron

  2. Evaluation of a root extract gel from Urtica dioica (Urticaceae) as ...

    African Journals Online (AJOL)

    Purpose: To develop and characterize an herbal gel prepared from methanol root extract of Urtica dioica (Urticaceae) (Stinging nettle) for the treatment of arthritis in mice. Methods: A methanol root extract from Urtica dioica was prepared, and a gel was then prepared using Carbopol 934. The prepared gel was subjected to ...

  3. Growth and study of barium oxalate single crystals in agar gel

    Indian Academy of Sciences (India)

    Barium oxalate was grown in agar gel at ambient temperature. The effect of various parameters like gel concentration, gel setting time and concentration of the reactants on the growth of these crystals was studied. Prismatic platy shaped spherulites and dendrites were obtained. The grown crystals were characterized by ...

  4. Tough ceramic coatings: Carbon nanotube reinforced silica sol-gel

    Science.gov (United States)

    López, A. J.; Rico, A.; Rodríguez, J.; Rams, J.

    2010-08-01

    Silica coatings reinforced with carbon nanotubes were produced via sol-gel route using two mixing techniques of the sol-gel precursors, mechanical and ultrasonic mixing, and dip-coating as deposition process on magnesium alloy substrates. Effective incorporation and distribution of 0.1 wt.% of carbon nanotubes in the amorphous silica matrix of the coatings were achieved using both techniques. Fabrication procedure determines the morphological aspects of the coating. Only mechanical mixing process produced coatings dense and free of defects. Nanoindentation technique was used to examine the influence of the fabrication process in the mechanical features of the final coatings, i.e. indentation fracture toughness, Young's modulus and hardness. A maximum toughening effect of about 24% was achieved in silica coatings reinforced with carbon nanotubes produced by the mechanical mixing route. Scanning electron microscopy investigation revealed that the toughening of these reinforced coatings was mainly due to bridging effect of the reinforcement.

  5. Unexpected decoupling of stretching and bending modes in protein gels.

    Science.gov (United States)

    Gibaud, Thomas; Zaccone, Alessio; Del Gado, Emanuela; Trappe, Véronique; Schurtenberger, Peter

    2013-02-01

    We show that gels formed by arrested spinodal decomposition of protein solutions exhibit elastic properties in two distinct frequency domains, both elastic moduli exhibiting a remarkably strong dependence on volume fraction. Considering the large difference between the protein size and the characteristic length of the network we model the gels as porous media and show that the high and low frequency elastic moduli can be respectively attributed to stretching and bending modes. The unexpected decoupling of the two modes in the frequency domain is attributed to the length scale involved: while stretching mainly relates to the relative displacement of two particles, bending involves the deformation of a strand with a thickness of the order of a thousand particle diameters.

  6. Luminescent hybrid porphyrinosilica obtained by sol gel chemistry

    Directory of Open Access Journals (Sweden)

    Neri Cláudio Roberto

    2003-01-01

    Full Text Available The sol-gel process is a methodology used to obtain organic-inorganic hybrid solids, which open new possibilities in the field of material science. The sol-gel technique offers a low temperature attractive approach for introducing organic molecules into amorphous materials. In order to introduce tetrakis (2-hydroxy-5-nitrophenylporphyrin covalently bounded to a silicate matrix, the inorganic precursor 3-isocyanatopropyltriethoxysilane was added (molar ratio 2:1 to the porphyrin solution in anhydrous dimethylformamide and triethylamine. The isolated porphyrin and the hybrid porphyrinosilica have excitation maximum centred at 400 nm and 424 nm, respectively and the emission spectra for both materials has bands centred at 650 nm and 713 nm. The formation of hybrid matrix was investigated by FTIR.

  7. Mechanical Properties of Gels; Stress from Confined Fluids

    Energy Technology Data Exchange (ETDEWEB)

    George W. Scherer

    2009-12-01

    Abstract for Grant DE-FG02-97ER45642 Period: 1997-2002 Mechanical Properties of Gels 2002-2008 Stress from Confined Fluids Principal investigator: Prof. George W. Scherer Dept. Civil & Env. Eng./PRISM Eng. Quad. E-319 Princeton, NJ 08544 USA Recipient organization: Trustees of Princeton University 4 New South Princeton, NJ 08544 USA Abstract: The initial stage of this project, entitled Mechanical Properties of Gels, was dedicated to characterizing and explaining the properties of inorganic gels. Such materials, made by sol-gel processing, are of interest for fabrication of films, fibers, optical devices, advanced insulation and other uses. However, their poor mechanical properties are an impediment in some applications, so understanding the origin of these properties could lead to enhanced performance. Novel experimental methods were developed and applied to measure the stiffness and permeability of gels and aerogels. Numerical simulations were developed to reproduce the growth process of the gels, resulting in structures whose mechanical properties matched the measurements. The models showed that the gels are formed by the growth of relatively robust clusters of molecules that are joined by tenuous links whose compliance compromises the stiffness of the structure. Therefore, synthetic methods that enhance the links could significantly increase the rigidity of such gels. The next stage of the project focused on Stress from Confined Fluids. The first problem of interest was the enhanced thermal expansion coefficient of water that we measured in the nanometric pores of cement paste. This could have a deleterious effect on the resistance of concrete to rapid heating in fires, because the excessive thermal expansion of water in the pores of the concrete could lead to spalling and collapse. A series of experiments demonstrated that the expansion of water increases as the pore size decreases. To explain this behavior, we undertook a collaboration with Prof. Stephen

  8. [Value of positive auto controls in the gel centrifugation method].

    Science.gov (United States)

    Eichler, H; Kretschmer, V

    1994-01-01

    We studied 97 samples of patients being positive in the autocontrol of the indirect antiglobulin test (IAT) in the gel system (DiaMed). In 83.2%, retesting with monospecific anti-IgG serum gave also positive results, due to a specific phenomenon caused, for example, by drug-specific antibodies (AB), warm auto-AB or allo-AB. In contrast, only 52.9% of the samples retested by the standard tube technique with polyspecific antiglobulin serum reacted positive. Only in 6 patients slightly increased cold agglutinins could be detected. None of the investigated patients showed any clinical or laboratory signs of hemolysis except one with pernicious anemia. We conclude that positive results of the autocontrol in the gel IAT should be confirmed by an additional DAT in the tube technique. If this second test shows a negative result, transfusions can take place without any restrictions.

  9. Study of gel formation by ionizing radiation in polypropylene

    Science.gov (United States)

    Oliani, W. L.; Parra, D. F.; Fermino, D. M.; Riella, H. G.; Lima, L. F. C. P.; Lugao, A. B.

    2013-03-01

    The objective of this work is to study the formation of microgel in pristine PP and modified PP. The modified PP in pellets was synthesized by gamma irradiation of pristine PP under a crosslinking atmosphere of acetylene in different doses of 5, 12.5 and 20 kGy, followed by thermal treatment for radical recombination and annihilation of the remaining radicals. The gel content of the modified polypropylenes was determined by extraction in boiling xylene for period of 12 h at 138 °C. The gel formed of pristine PP and modified (i.e., irradiated) was characterized using optical microscopy (OM), scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR) and X-ray diffraction (XDR). The PP morphological study indicated the microgel formation with increase of spherulitic concentration with dose.

  10. Breeder fuel pellet fabrication from gel-sphere conversion

    International Nuclear Information System (INIS)

    McLemore, D.R.; Bennett, D.W.; Hart, P.E.; Norman, R.E.

    1980-01-01

    The development of automated nuclear fuel fabrication methods is the goal of the United States breeder reactor program and will form the technological basis for the future breeder reactor fuel supply. A major factor in achieving this goal is the development of remotely operated fuel fabrication equipment. The program schedule is to demonstrate the feasibility of automated pellet fuel fabrication and remote maintenance techniques by the mid-1980's. Development of major ceramic unit operations and the required computer control system is currently in the engineering testing stage. This report describes the planned program activities for evaluating the gel-sphere conversion process and demonstrating the fabrication of breeder fuel pellets from these gel-derived spheres

  11. Stimuli Responsive Poly(Vinyl Caprolactam Gels for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Kummara Madhusudana Rao

    2016-01-01

    Full Text Available Poly(vinyl caprolactam (PNVCL is one of the most important thermoresponsive polymers because it is similar to poly(N-isopropyl acrylamide. PNVCL precipitates from aqueous solutions in a physiological temperature range (32–34 °C. The use of PNVCL instead of PNIPAM is considered advantageous because of the assumed lower toxicity of PNVCL. PNVCL copolymer gels are sensitive to external stimuli, such as temperature and pH; which gives them a wide range of biomedical applications and consequently attracts considerable scientific interest. This review focuses on the recent studies on PNVCL-based stimuli responsive three dimensional hydrogels (macro, micro, and nano for biomedical applications. This review also covers the future outlooks of PNVCL-based gels for biomedical applications, particularly in the drug delivery field.

  12. Aloe Gel Enhances Angiogenesis in Healing of Diabetic Wound

    Directory of Open Access Journals (Sweden)

    Djanggan Sargowo

    2011-12-01

    Full Text Available BACKGROUND: Diabetic micro and macroangiophathy lead to the incident of diabetic foot ulcers characterized by an increased number of circulating endothelial cells (CECs and decreased function of endothelial progenitor cells (EPCs. This fact is correlated with ischemia and diabetic wound healing failure. Aloe vera gel is known to be able to stimulate vascular endothelial growth factor (VEGF expression and activity by enhancing nitric oxide (NO production as a result of nitric oxide synthase (NOS enzyme activity. Aloe vera is a potential target to enhancing angiogenesis in wound healing. OBJECTIVE: The objective of this study was to explore the major role of Aloe vera gel in wound healing of diabetic ulcers by increasing the level of EPCs, VEGF, and endothelial nitric oxide synthase (eNOS, as well as by reducing the level of CECs involved in angiogenesis process of diabetic ulcers healing. METHODS: The experimental groups was divided into five subgroups consisting of non diabetic wistar rats, diabetic rats without oral administration of aloe gel, and treatment subgroup (diabetic rats with 30, 60 and 120 mg/day of aloe gel doses for 14 days. All subgroups were wounded and daily observation was done on the wounds areas. Measurement of the number of EPCs (CD34, and CECs (CD45 and CD146 was done by flow cytometry, followed by measurement of VEGF and eNOS expression on dermal tissue by immunohistochemical method on day 0 and day 14 after treatment. The quantitative data were analyzed by One-Way ANOVA and Linear Regression, with a confidence interval 5% and significance level (p<0.05 using SPSS 16 software to compare the difference and correlation between wound diameters, number of EPCs and CECs as well as the levels of VEGF and eNOS. RESULTS: The results of this study showed that aloe gel oral treatment in diabetic wistar rats was able to accelerate the wound healing process. It was shown by significant reduction of wound diameter (0.27±0.02; the

  13. Gels of sodium alginate‒chitosan interpolyelectrolyte complexes

    Science.gov (United States)

    Brovko, O. S.; Palamarchuk, I. A.; Val'chuk, N. A.; Chukhchin, D. G.; Bogolitsyn, K. G.; Boitsova, T. A.

    2017-08-01

    Aspects of the formation of gels of interpolyelectrolyte complexes (IPECs) based on sodium alginate (NaAlg) and chitosan are studied. The effect the conditions of synthesis and complex composition have on the morphological structure and functional properties of these complexes is examined. It is established that complexation in this system proceeds according to a mechanism of electrostatic interaction between the oppositely charged carboxylic groups of the L-hyaluronic acid pyranose cycles of NaAlg proximal polymer chains and chitosan's amino groups, along with a multitude of hydrogen bonds and dispersion forces. We show that the mechanism of IPEC formation is strongly influenced by the conformational state of a lyophilizing component that is present in the system in excess. The inner surfaces of cryogels based on NaAlg‒chitosan IPECs is found to be strongly influenced by the degree of conversion between the parental polyelectrolytes. The most developed mesoporous structure is obtained when a denser gel forms in the system.

  14. Structural and Electrochemical Analysis of PMMA Based Gel Electrolyte Membranes

    Directory of Open Access Journals (Sweden)

    Chithra M. Mathew

    2015-01-01

    Full Text Available New gel polymer electrolytes containing poly(vinylidene chloride-co-acrylonitrile and poly(methyl methacrylate are prepared by solution casting method. With the addition of 60 wt.% of EC to PVdC-AN/PMMA blend, ionic conductivity value 0.398×10-6 S cm−1 has been achieved. XRD and FT-IR studies have been conducted to investigate the structure and complexation in the polymer gel electrolytes. The FT-IR spectra show that the functional groups C=O and C≡N play major role in ion conduction. Thermal stability of the prepared membranes is found to be about 180°C.

  15. Structure and amphoteric properties of titanium dioxide gels

    International Nuclear Information System (INIS)

    Kertesz, C.

    1991-01-01

    Mechanisms responsible for the in-solution ion retention by titanium dioxide are studied. Mineral oxide gel formation and structure are described and various titanium dioxide gel synthesis modes are presented. A two-phase model, taking into account the porous nature of the solid and allowing for the application of the mass action law, is adopted. The oxide amphoteric properties are studied with the potentiometric titration technique. Hysteresis loops are imputed to the slowness of the acid-basic neutralization reaction. The main characteristics are determined: isoelectric point, cation and anion retention capacity. Depending on the suspension agitation, the speed limiting factor may be the diffusion in the film or the diffusion in the particle. 60 fig., 128 ref

  16. Electrophoretic deposition of sol-gel-derived ceramic coatings

    International Nuclear Information System (INIS)

    Zhang, Y.; Crooks, R.M.

    1992-01-01

    In this paper the physical, optical, and chemical characteristics of electrophoretically and dip-coated sol-gel ceramic films are compared. The results indicate that electrophoresis may allow a higher level of control over the chemistry and structure of ceramic coatings than dip-coating techniques. For example, controlled-thickness sol-gel coatings can be prepared by adjusting the deposition time or voltage. Additionally, electrophoretic coatings can be prepared in a four-component alumino-borosilicate sol display interesting optical characteristics. For example, the ellipsometrically-measured refractive indices of electrophoretic coatings are higher than the refractive indices of dip-coated films cast from identical sols, and they are also higher than any of the individual sol components. This result suggests that there are physical and/or chemical differences between films prepared by dip-coating and electrophoresis

  17. Papain-gel Degrades Intact Nonmineralized Type I Collagen Fibrils

    Science.gov (United States)

    BERTASSONI, L. E.; MARSHALL, G. W.

    2010-01-01

    Summary Papain-gel has been utilized as a chemomechanical material for caries removal due to its ability to preserve underlying sound dentin. However, little is known about the effect of the papain enzyme on intact type I collagen fibrils that compose the dentin matrix. Here we sought to define structural changes that occur in intact type I collagen fibrils after an enzymatic treatment with a papaingel. Intact and nonmineralized type I collagen fibrils from rat tail were obtained and treated with a papain-gel (Papacarie) for 30 s, rinsed with water and imaged using an atomic force microscope (AFM). Additionally, polished healthy dentin specimens were also treated using the same protocol described above and had their elastic modulus (E) and hardness (H) measured by means of AFM-based nanoindentation. AFM images showed that the papain-gel induced partial degradation of the fibrils surface, yet no rupture of fibrils was noticed. The distinction between gap and overlap zones of fibrils vanished in most regions after treatment, and overlap zones appeared to be generally more affected. Mechanical data suggested a gradual decrease in E and H after treatments. A significant two-fold drop from the values of normal dentin (E= 20 +/− 1.9, H = 0.8 +/− 0.08 GPa) was found after four applications (E = 9.7 +/− 3.2, H = 0.24 +/− 0.1 GPa) ( P<0.001), which may be attributed to the degradation of proteoglycans of the matrix. In summary, this study provided novel evidence that intact nonmineralized type I collagen fibrils are partially degraded by a papain-gel. PMID:20205185

  18. Sol-Gel Synthesis of Non-Silica Monolithic Materials

    Science.gov (United States)

    Gaweł, Bartłomiej; Gaweł, Kamila; Øye, Gisle

    2010-01-01

    Monolithic materials have become very popular because of various applications, especially within chromatography and catalysis. Large surface areas and multimodal porosities are great advantages for these applications. New sol-gel preparation methods utilizing phase separation or nanocasting have opened the possibility for preparing materials of other oxides than silica. In this review, we present different synthesis methods for inorganic, non-silica monolithic materials. Some examples of application of the materials are also included.

  19. Liquid Crystal Gel Reduces Age Spots by Promoting Skin Turnover

    OpenAIRE

    Mina Musashi; Ariella Coler-Reilly; Teruaki Nagasawa; Yoshiki Kubota; Satomi Kato; Yoko Yamaguchi

    2014-01-01

    Studies have shown that liquid crystals structurally resembling the intercellular lipids in the stratum corneum can beneficially affect the skin when applied topically by stimulating the skin’s natural regenerative functions and accelerating epidermal turnover. In the present study, the effects of applying low concentrations of a liquid crystal gel of our own creation were evaluated using epidermal thickening in mouse skin as an assay for effective stimulation of epidermal turnover. A liquid ...

  20. The role of the solvent in PMMA gel polymer\

    Czech Academy of Sciences Publication Activity Database

    Vondrák, J.; Musil, M.; Sedlaříková, M.; Kořínek, Radim; Bartušek, Karel; Fedorková, A.

    2016-01-01

    Roč. 2, č. 1 (2016), s. 6-12 E-ISSN 2300-3545 R&D Projects: GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : gel polymer electrolyte * TGA * NMR spectroscopy * conductivity * sodium polymer electrolyte Subject RIV: BH - Optics, Masers, Lasers https://www.degruyter.com/view/j/eetech.2016.2.issue-1/eetech-2016-0002/eetech-2016-0002. xml