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1

Complex III staining in blue native polyacrylamide gels.  

PubMed

For more than a decade now blue native polyacrylamide gel electrophoresis (BN-PAGE) has been used for the study of the oxidative phosphorylation (OXPHOS) complexes. Catalytic activities of complexes I, II, IV and V can be assessed, after separation by gel electrophoresis, by incubation of the BN-PAGE gel in specific staining solutions. However, until now, a reliable staining method for testing ubiquinol cytochrome c oxidoreductase (complex III) activity by BN-PAGE gel techniques was not available. In addition, spectrophotometric methods currently in use for detection of complex III deficiency in patients are not very sensitive. Here, we describe a newly developed diagnostic method for visualization of complex III activity by direct in-gel evaluation of ubiquinol cytochrome oxidoreductase activity. We validated the method by reporting the results in six patients with previously characterised complex III defects. PMID:21484424

Smet, Joél; De Paepe, Boel; Seneca, Sara; Lissens, Willy; Kotarsky, Heike; De Meirleir, Linda; Fellman, Vineta; Van Coster, Rudy

2011-06-01

2

Detection of serum proteins by native polyacrylamide gel electrophoresis using Blue Sepharose CL6B-containing stacking gels  

Microsoft Academic Search

Analysis of serum proteins by native polyacrylamide gel electrophoresis is difficult because albumin is abundant in serum and interferes with the resolution of other proteins, especially ?-antitrypsin which has mobility that is very similar to that of albumin. We present here a method in which serum proteins are separated by polyacrylamide gel electrophoresis using stacking gels containing Blue Sepharose CL-6B,

Haruhiro Muratsubaki; Kaoru Satake; Yasuhisa Yamamoto; Keiichiro Enomoto

2002-01-01

3

'Laterally aggregated' polyacrylamide gels for electrophoresis.  

PubMed

A new method is described for producing highly porous polyacrylamide matrices: polymerization in presence of a preformed hydrophilic polymer. If a standard mixture of monomers (e.g., 5%T, 4%C) is polymerized in presence of, e.g., polyethylene glycol (PEG) 10 kDa, lateral chain aggregation occurs, with formation of large pore sizes. In PEG 10 kDa, the transition from a small- to a large-pore gel is clearly apparent at 0.5% PEG addition and reaches a plateau already at 2.5% PEG. Even with shorter PEG fragments (6.2 and 1 kDa) this transition occurs, but with progressively larger amounts of PEG in solution (up to 25% for the 1 kDa species). Other polymers such as hydroxymethyl cellulose (1000 kDa) and polyvinyl-pyrrolidone (360 kDa and 25 kDa) are also able to elicit this phenomenon. It appears that lateral chain aggregation (before the cross-linking event) is induced via intra-chain hydrogen bonding, since urea and temperature strongly inhibit it, whereas tetramethylurea (an agent quenching hydrophobic interactions) does not hamper it. By scanning electron microscope, it is found that the maximum pore size obtained in a 5%T, 4%C gel in presence of 2.5% PEG 10 kDA is of the order of 0.5 micron, whereas the same 5%T, 4%C control gel would have an average pore diameter of 5 nm. Thus, an increment of pore size of about 2 orders of magnitude is obtained: in these new matrices, a 21000 bp DNA fragment exhibits a much greater migration than in a control gel in which the sample is entrapped at the application site. PMID:1459071

Righetti, P G; Caglio, S; Saracchi, M; Quaroni, S

1992-01-01

4

A technique for detecting antifungal activity of proteins separated by polyacrylamide gel electrophoresis.  

PubMed

A technique was developed for the detection of antifungal activity of proteins after discontinuous polyacrylamide gel electrophoresis under native conditions. The antifungal activity is detected as growth inhibition zones in a homogeneous fungal lawn, grown in an agar layer spread on top of the polyacrylamide gel. The position of proteins with antifungal activity can be determined on a diffusion blot prepared from the same gel. The technique is illustrated for three antifungal plant proteins, i.e. alpha-purothionin, Urtica dioica agglutinin, and tobacco chitinase. PMID:1889394

De Bolle, M F; Goderis, I J; Terras, F R; Cammue, B P; Broekaert, W F

1991-06-01

5

Polyacrylamide gel with switchable trypsin activity for analysis of proteins.  

PubMed

Trypsin was immobilized on a variety of materials to improve digestion efficiency. However, because the immobilized trypsin will digest proteins during electrophoresis, direct immobilization of active trypsin in polyacrylamide gel will compromise the protein separation. To overcome this problem, here we report a novel polyacrylamide gel with switchable trypsin activity. It was prepared by copolymerization of the PEG-trypsin-aprotinin complex during the gel-casting step. Because the inhibitor aprotinin binds strongly with trypsin at alkaline pH, this novel gel does not display hydrolytic activity during electrophoresis. After electrophoresis, the activity of trypsin embedded in gel could be recovered by simply washing away the bound inhibitor at a low pH. It was demonstrated that this unique switchable activity design allowed high resolution of the complex protein mixture during electrophoresis and highly efficient digestion of the separated proteins in situ in the gel after electrophoresis. PMID:23855779

Liu, Fangjie; Ye, Mingliang; Wang, Chunli; Hu, Zhengyan; Zhang, Yi; Qin, Hongqiang; Cheng, Kai; Zou, Hanfa

2013-08-01

6

Direct immunodetection of antigens within the precast polyacrylamide gel.  

PubMed

Detection of specific proteins separated by SDS-PAGE is the basis for studying specific antigens. Immunodetection of antigens is commonly performed using Western blotting technique. In this paper we have shown that it is possible to eliminate Western blotting and to detect the antigens directly within the precast polyacrylamide gels by pretreating the gels with 50% isopropanol followed by distilled water treatment. This method would be valuable for large or difficult to transfer proteins. PMID:11567532

Desai, S; Dworecki, B; Cichon, E

2001-10-01

7

X-ray CT dose in normoxic polyacrylamide gel dosimetry  

Microsoft Academic Search

This study reports on the effects of x-ray CT dose in CT imaged normoxic polyacrylamide (nPAG) gel dosimeters. The investigation is partitioned into three sections. First, the CT dose absorbed in nPAG is quantified under a range of typical gel CT imaging protocols. It is found that the maximum absorbed CT dose occurs for volumetric imaging and is in the

P. Baxter; A. Jirasek; M. Hilts

2007-01-01

8

Activity staining of endoglucanases in polyacrylamide gels.  

PubMed

The endoglucanases of Penicillium funiculosum were analyzed for the presence of multiple forms using a modified version of the Congo red method. Postelectrophoretic slab gels were directly incubated in a solution of carboxymethylcellulose for a period as short as 15 min and then the activities were visualized by staining with Congo red. Ten distinct bands of clearances were obtained indicating the presence of at least as many multiple forms. PMID:1280921

Mathew, R; Rao, K K

1992-10-01

9

Reuse of denaturing polyacrylamide gels for short tandem repeat analysis.  

PubMed

Denaturing polyacrylamide gel electrophoretic analysis of amplified polymorphic short tandem repeat (STR) loci using fluorescent markers is a mainstay of forensic and paternity testing. To reduce the drawback of preparing gels or using expensive precast gels, we have developed a simple and rapid method to reuse gels between 2 and 8 times over a period of several days. Following the initial electrophoresis and scan, the original samples are removed from the gel by a 1-1.5-h reverse-electrophoresis step. This step heats the gel for the next set of samples and can be performed several days after the initial electrophoresis. Sample bands remain sharp on subsequent runs, but edge effects (frowning of the outside lanes) become progressively worse and ultimately limit gel reuse. Well distortions and separation of the gel from the plates become problems if the gel is used more than twice. However, degassing the gel solution and bonding the gel to both plates eliminate these problems. Precast gels also can be used multiple times. Using this technique, we have successfully analyzed samples amplified with a nine-locus multiplex system and characterized the separated products using a fluorescent scanner and software. PMID:9821592

Tereba, A; Micka, K A; Schumm, J W

1998-11-01

10

Photopatterned free-standing polyacrylamide gels for microfluidic protein electrophoresis.  

PubMed

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 ?m tall) are directly photopatterned atop of and covalently attached to planar polymer or glass surfaces. Leveraging the fast <1 h design-prototype-test cycle - significantly faster than mold based fabrication techniques - we optimize the fsPAG architecture to minimize injection dispersion for rapid (<1 min) and short (1 mm) protein separations. The facile fabrication and prototyping of the fsPAGE provides researchers a powerful tool for developing custom analytical assays. We highlight the utility of assay customization by fabricating a polyacrylamide gel with a spatial pore-size distribution and demonstrate the resulting enhancement in separation performance over a uniform gel. Further, we up-scale from a unit separation to an array of 96 concurrent fsPAGE assays in 10 min run time driven by one electrode pair. The fsPAG array layout matches that of a 96-well plate to facilitate integration of the planar free standing gel array with multi-channel pipettes while remaining compatible with conventional slab-gel PAGE reagents, such as staining for label-free protein detection. Notably, the entire fsPAGE workflow from fabrication, to operation, and readout uses readily available materials and instruments - making this technique highly accessible. PMID:23609800

Duncombe, Todd A; Herr, Amy E

2013-06-01

11

Swelling of hydrophobically modified poly(acrylamide) and poly(acrylamide)- co -(acrylic acid) gels in surfactant solutions  

Microsoft Academic Search

A series of hydrophobically modified polyacrylamide and polyacrylamide-co-poly(acrylic acid) gels with systematically varying hydrophobicity were prepared by free-radical polymerization of acrylamide,\\u000a n-alkylacrylamides (n?=?10, 12, and 14), and acrylic acid. The swelling of these gels was examined in water and in both anionic and cationic surfactant\\u000a solutions. It was found that the gels which incorporated acrylic acid showed extremely high swelling

B. H. Brouwer White; J. C. T. Kwak

1999-01-01

12

Basics and recent advances of two dimensional- polyacrylamide gel electrophoresis  

PubMed Central

Gel- based proteomics is one of the most versatile methods for fractionating protein complexes. Among these methods, two dimensional- polyacrylamide gel electrophoresis (2-DE) represents a mainstay orthogonal approach, which is popularly used to simultaneously fractionate, identify, and quantify proteins when coupled with mass spectrometric identification or other immunological tests. Although 2-DE was first introduced more than three decades ago, several challenges and limitations to its utility still exist. This review discusses the principles of 2-DE as well as both recent methodological advances and new applications.

2014-01-01

13

Basics and recent advances of two dimensional- polyacrylamide gel electrophoresis.  

PubMed

Gel- based proteomics is one of the most versatile methods for fractionating protein complexes. Among these methods, two dimensional- polyacrylamide gel electrophoresis (2-DE) represents a mainstay orthogonal approach, which is popularly used to simultaneously fractionate, identify, and quantify proteins when coupled with mass spectrometric identification or other immunological tests. Although 2-DE was first introduced more than three decades ago, several challenges and limitations to its utility still exist. This review discusses the principles of 2-DE as well as both recent methodological advances and new applications. PMID:24735559

Magdeldin, Sameh; Enany, Shymaa; Yoshida, Yutaka; Xu, Bo; Zhang, Ying; Zureena, Zam; Lokamani, Ilambarthi; Yaoita, Eishin; Yamamoto, Tadashi

2014-01-01

14

Partition and permeation of dextran in polyacrylamide gel.  

PubMed Central

Partition of sized FITC-dextrans in polyacrylamide gel showed a relationship between Kav and solute radius as predicted by the theory of Ogston, which is based solely on geometry of the spaces. Permeability data for the same dextrans were fit to several theories, including those based on geometry and those based on hydrodynamic interactions, and the gel structure predicted by the partition and permeability data were compared. The Brinkman effective-medium model (based on hydrodynamic interactions and requiring a measure of the hydraulic conductivity of the matrix) gave the best fit of permeability data with the values for fiber radius (rf) and void volume of the gel (epsilon) that were obtained from the partition data. The models based on geometry and the hydrodynamic screening model of Cukier, using the rf and epsilon from partition data, all predicted higher rates of permeation than observed experimentally, while the effective-medium model with added term for steric interaction predicted lower permeation than that observed. The size of cylindrical pores appropriate for the partition data predicted higher rates of permeation than observed. These relative results were unaffected by the method of estimating void volume of the gel. In sum, it appears that one can use data on partition of solute, combined with measurement of hydraulic conductivity, to predict solute permeation in polyacrylamide gel.

Williams, J C; Mark, L A; Eichholtz, S

1998-01-01

15

Plant Nucleases: III. Polyacrylamide Gel Electrophoresis of Corn Ribonuclease Isoenzymes.  

PubMed

Isoenzymes of RNase were detected in plant extracts after polyacrylamide gel electrophoresis with a new buffer system. The gels were incubated in an RNA solution, then dipped for 30 seconds into 0.2% toluidine blue. The method is rapid and is sensitive to very small amounts of RNase. The effects of buffers and ethylenediaminetetraacetate on the different enzymes are illustrated by photographs and scans of the gels.RNase I, from endosperms and roots, was the fastest-moving corn RNase. Two isoenzymes of corn RNase II, from microsomes, were detected in the hybrid WF9 x M14, while each parental inbred had one of the isoenzymes. Three isoenzymes of corn Nuclease I, from crude mitochondria, had about the same mobility as the RNase II isoenzymes, but were inhibited by ethylenediaminetetraacetate. RNases were also detected in tobacco and wild carrot tissue cultures. PMID:16657737

Wilson, C M

1971-07-01

16

Investigations in x-ray computed tomography polyacrylamide gel dosimetry  

SciTech Connect

Polyacrylamide gels (PAGs) are radiosensitive materials currently under development for use as three-dimensional (3D) dosimeters in radiation therapy. Dose information is recorded in the gels and extracted through imaging. X-ray computed tomography (CT) has emerged as a promising gel imaging method due to a change in gel density that occurs upon irradiation. The accessibility of CT technology to cancer hospitals makes CT read out clinically attractive; however, the technique remains of limited clinical use due in part to poor dose resolution. This thesis investigates the use of CT for extracting dose information from PAGs with an overall goal of improving achievable dose resolution. Thesis results are divided into three studies: a gel-compositional study, a study of noise and dose resolution, and a digital filtering study. The first study investigates the effects of gel composition on PAG CT dose response and the underlying density change. Results indicate dramatic variation in CT dose response sensitivity and range with gel composition. A model is developed to describe gel density change with dose, revealing two fundamental properties of the density to dose response: the density change per unit polymer yield is highest for gels with low and high concentrations of crosslinking molecules, and dose response sensitivity is linearly dependent on the total concentration of monomers in the gel. The second study investigates strategies for minimizing noise in CT polymer gel dosimetry and assesses system performance. Specifically, the effects of phantom design, scanning technique, and voxel size on image noise are investigated and the effect of scanning protocol on imaging time is established. The dose resolution achievable with an optimized system is then calculated, given voxel size and imaging time constraints, and compared with published values for magnetic resonance imaging (MRI) and optical CT gel dosimetry. The third study investigates the potential of image filtering for improved dose resolution in CT gel dosimetry. CT image noise is characterized and appropriate filters are tested on a CT image of a PAG irradiated with a clinically relevant dose distribution. Filter performance is found to vary dramatically, with the best filters more than halving the dose resolution without significantly distorting the spatial distribution of dose. In summary, this thesis provides insight into the fundamental nature of PAG density to dose response, develops strategies for minimizing image noise, quantifies system performance, and demonstrates that digital image filtering is an effective tool to provide additional improvements to dose resolution.

Hilts, Michelle [Physics and Astronomy, University of British Columbia, British Columbia, Canada and Medical Physics, BC Cancer Agency, Vancouver Centre, British Columbia (Canada)]. E-mail: mhilts@bccancer.bc.ca

2005-09-15

17

Protein diffusion in charged polyacrylamide gels. Visualization and analysis.  

PubMed

Protein diffusion in anionic, cross-linked polyacrylamide-based gels supported in fused-silica capillaries was characterized by a direct visualization method. Microphotography was used to obtain transient protein concentration profiles in these gels using cytochrome c as a probe molecule. Gels based on acrylamido-methylpropane sulfonic acid with 2.5-10% N,N'-methylene-bisacrylamide as a cross-linker and with a total polymer concentration of 0.21 g/cm3 yielded diffuse protein concentration profiles which were quantitatively consistent with a Fickian diffusion model. An analytical method was developed to calculate the diffusivity as a function of protein concentration in the gel from the experimental profiles. The diffusivity was found to assume values in the range 2.5-5.5x10(-8) cm2/s and varied somewhat with the protein concentration in the gel. The effects of some of the polymer properties, such as cross-link density, polymer concentration and charge, were also investigated for a limited range of conditions to derive qualitative trends. Results showed that the transport rates increased with a decrease in the cross-link density, were extremely reduced when the polymer concentration was doubled, and were slightly increased when the charge density was decreased by half by polymerizing a 1:1 mixture of acrylamide and acrylamido-methylpropane sulfonic acid monomers. PMID:10674938

Lewus, R K; Carta, G

1999-12-31

18

Serial electrophoretic transfers: A technique for the identification of numerous enzymes from single polyacrylamide gels  

Microsoft Academic Search

We describe an electrophoretic method for the transfer of macromolecules from polyacrylamide slab gels to ion-exchange paper without loss of clarity or resolution. A series of partial transfers provides numerous copies of a single gel separation, and these copies may be assayed independently with enzyme specific stains. This method therefore combines the advantages of polyacrylamide gel electrophoresis for detecting enzyme

Tracy McLellan; John A. M. Ramshaw

1981-01-01

19

Cost-effective and efficient apparatus for electroelution of micro- and macrogram quantities of proteins from polyacrylamide gels.  

PubMed

Protein recovery from gel electrophoresis plays a significant role in functional genomics and proteomics. To assist in this, a simple, cost-effective, and efficient apparatus for electroelution of proteins has been designed. The performance of the apparatus was demonstrated using the proteins bovine serum albumin (BSA), phosphorylase, ovalbumin, pepsin, and trypsinogen. In all the cases the yield of elution was found to be consistently greater than 85% and the proteins could be eluted without degradation in less than 15 min. The utility of this method can be extended to protein elution from denatured and native polyacrylamide gels, DNA purification from agarose gels, and oligomeric primers purification from polyacrylamide gels. In addition to this, the method offers an effortless purification and characterization of microbial extracellular proteins. The eluted proteins can be directly used in N-terminal amino acid sequencing, and in amino acid and proteomics analyses. PMID:24279712

Reddy, Gundlapally Sathyanarayana

2014-11-17

20

X-ray CT dose in normoxic polyacrylamide gel dosimetry  

SciTech Connect

This study reports on the effects of x-ray CT dose in CT imaged normoxic polyacrylamide (nPAG) gel dosimeters. The investigation is partitioned into three sections. First, the CT dose absorbed in nPAG is quantified under a range of typical gel CT imaging protocols. It is found that the maximum absorbed CT dose occurs for volumetric imaging and is in the range of 4.6{+-}0.2 cGy/image. This does scales linearly with image averaging. Second, using Raman spectroscopy, the response of nPAG to CT imaging photon energies (i.e., 120-140 kVp) is established and compared to the well known dose response of nPAG exposed to 6 MV photons. It is found that nPAG exhibits a weaker response (per unit dose) to 140-kVp incident photons as compared to 6 MV incident photons (slopes m{sub 6MV}=-0.0374{+-}0.0006 Gy{sup -1} and m{sub 140kVp}=-0.016{+-}0.001 Gy{sup -1}). Finally, using the above data, an induced change in CT number ({delta}N{sub CT}) is calculated for nPAG imaged using a range of gel imaging protocols. It is found that under typical imaging protocols (120-140 kVp, 200 mAs, {approx}16-32 image averages) a {delta}N{sub CT}<0.2 H is induced in active nPAG dosimeters. This {delta}N{sub CT} is below the current limit of detectability of CT nPAG polymer gel dosimetry. Under expanded imaging protocols (e.g., very high number of image averages) an induced {delta}N{sub CT} of {approx}0.5 H is possible. In these situations the additional polymerization occurring in nPAG due to the imaging process may need to be accounted for.

Baxter, P.; Jirasek, A.; Hilts, M. [Department of Physics and Astronomy, University of Victoria, Victoria BC V8W 3P6 (Canada); Medical Physics, BC Cancer Agency-Vancouver Island Centre, Victoria BC V8R 6V5 (Canada)

2007-06-15

21

The gel edge electric field gradients in denaturing polyacrylamide gel electrophoresis.  

PubMed

It has previously been shown that zones of higher electric field form close to the loading end of the gel during denaturing polyacrylamide gel electrophoresis. Here we show that the field can reach up to three times its normal mean value a few cm in front of the loading wells when 44.5 mM Tris-44.5 mM boric acid-1 mM EDTA is used as the gel buffer. We also demonstrate that this electric field gradient is mostly due to the difference in ion transference numbers at the gel/buffer interface caused by the high viscosity of the urea solution contained in the gel. This field gradient leads to increased band widths and forces us to redefine both the electrophoretic mobility and the mean field intensity. We discuss some methods that can be used to minimize the effects of this gradient. PMID:9629888

Desruisseaux, C; Slater, G W; Drouin, G

1998-05-01

22

Nonreducing two-dimensional polyacrylamide gel electrophoretic analysis of human colonic proteins.  

PubMed

Immunochemical detection of proteins with antigenic determinants that are dependent on the native spatial conformation of the protein can often pose problems with conventional two-dimensional polyacrylamide gel electrophoresis (2-DE). For example, many antigenic determinants are readily destroyed by reducing agents and/or urea, reagents which are critical components of many of the conventional isoelectric focusing and immobilized-pH-gradient (IPG) protocols used in the first electrophoretic dimension. Here we describe the use of commercially available precast 2-DE gels for performing nonreducing/non-urea 2-DE of proteins extracted from the human colon cancer cell line LIM 1215 with 0.3% Triton X-100 that permit the identification of antigens with conformational determinants by immunoblot analysis. Previous, related studies demonstrated the usefulness of peptide-mass fingerprinting for identifying 2-DE resolved proteins. Here we show how partial protein sequence data obtained by rapid peptide mapping, using capillary column liquid chromatography directly coupled with electrospray ionization tandem mass spectrometric methodologies, enhances the usefulness of this approach for identifying incompletely resolved proteins. The nonreducing 2-DE gel images reported in this study, along with our master 2-DE gel protein database for both normal human colonic crypts and several colon-cancer-derived cell lines, and information regarding microtechniques employed in this laboratory for obtaining structural data on 2-DE resolved proteins can be accessed over the Internet using World Wide Web (URL address: http:@www.ludwig.edu.au). PMID:7498156

Reid, G E; Ji, H; Eddes, J S; Moritz, R L; Simpson, R J

1995-07-01

23

A versatile polyacrylamide gel electrophoresis based sulfotransferase assay  

PubMed Central

Background Sulfotransferases are a large group of enzymes that regulate the biological activity or availability of a wide spectrum of substrates through sulfation with the sulfur donor 3'-phosphoadenosine-5'-phosphosulfate (PAPS). These enzymes are known to be difficult to assay. A convenient assay is needed in order to better understand these enzymes. Results A universal sulfotransferase assay method based on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) is described. This assay has been successfully applied to substrates as small as ?-naphthol and as big as proteoglycans. As examples, we present the assays for recombinant human CHST4, TPST1, CHST3 and HS6ST1. In order to assess whether a small molecule can be applicable to this type of assay, a method to estimate the relative mobility of a molecule to PAPS is also presented. The estimated relative mobilities of various sulfated small molecules generated by SULT1A1, SULT1E1, SULT2A1 and CHST4 are in the range of ± 0.2 of the actual relative mobilities. Conclusion The versatility of the current method comes from the ability that SDS-PAGE can separate proteins and small molecules according to different parameters. While mobilities of proteins during SDS-PAGE are inversely related to their sizes, mobilities of small molecules are positively related to their charge/mass ratios. The predicted relative mobility of a product to PAPS is a good indicator of whether a sulfotransferase can be assayed with SDS-PAGE. Because phosphorylation is most similar to sulfation in chemistry, the method is likely to be applicable to kinases as well.

2010-01-01

24

Proton Diffusion and T 1Relaxation in Polyacrylamide Gels: A Unified Approach Using Volume Averaging  

Microsoft Academic Search

The structure of polyacrylamide gels was studied using proton spin–lattice relaxation and PFG diffusion methods. Polyacrylamide gels, with total polymer concentrations ranging from 0.25 to 0.35 g\\/ml and crosslinker concentrations from 0 to 10% by weight, were studied. The data showed no effect of the crosslinker concentration on the diffusion of water molecules. The Ogston–Morris and Mackie–Meares models fit the

Brigita Penke; Stephen Kinsey; Stephen J. Gibbs; Timothy S. Moerland; Bruce R. Locke

1998-01-01

25

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

PubMed

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

Day, I N; Humphries, S E

1994-11-01

26

Detection of cellulase activity in polyacrylamide gels using Congo red-stained agar replicas.  

PubMed

Bands that have cellulolytic activity are visualized after polyacrylamide gel electrophoresis by laying the slab gel on top of a thin sheet of 2% agar containing 0.1% carboxymethylcellulose. After a suitable incubation time, zones of carboxymethylcellulose hydrolysis are revealed by staining the agar replica with Congo red. PMID:6193735

Béguin, P

1983-06-01

27

Structural Characterization of templated polyacrylamide gels by small angle X-ray scattering *  

NASA Astrophysics Data System (ADS)

The use of surfactant micelles to template pores into a polyacrylamide gel matrix has been suggested to increase size selectivity of macromolecular separations on them. Various surfactant molecules such as, Sodium dodecyl (laurel) sulfate (SDS), Didodecyldimethyl ammonium bromide (DDAB), Cetyltrimethyl ammonium bromide (CTAB) and, Tetradecyltrimethyl ammonium bromide (TTAB) have been shown to produce templating effects on polyacrylamide and other gels. Small angle X-ray scattering (SAXS) is an excellent tool for investigating the structure of materials. Ideally, analysis of SAXS patterns can reveal the average shape and dimensions of individual micelles, the spacing between them, and the overall structure of the system. Several reports of SAXS measurements of SDS in buffer are available. The system of SDS in polyacrylamide is comparatively new. These systems have been investigated using SAXS, in order to gain some understanding of how the templating process affects the micellar system and the gel matrix. SAXS experiments to elucidate the structure of the micelle/gel systems are reported.

Chakrapani, Mukundan; van Winkle, David H.

2000-03-01

28

Resolution of glycogen phosphorylase isoenzymes in precast PhastSystem polyacrylamide gels.  

PubMed

Homogeneous (7.5%) and gradient (10-15%) ultrathin nondenaturating miniaturized polyacrylamide gels (Pharmacia PhastGel media) were used to separate glycogen phosphorylase isoforms from rabbit muscle, rat liver and brain, MH 3924A cells, a dedifferentiated hepatocellular carcinoma of the rat, and C1I cells, a nontumorigenic epithelial rat liver cell line. The enzymes were detected by in situ phosphorylase assay and by immunoblotting. Phosphorylase proteins from the brain, MH 3924A, and C1I exhibited similar electrophoretic mobility, which was different from that of the enzymes from the muscle and normal liver. Molecular weight determination from sodium dodecyl sulfate gels yielded similar data for the subunits of muscle and liver enzymes (98,000 and 96,000), respectively, on one hand, and brain, MH 3924A tumor, and nontumorigenic C1I cells (93,000, 93,000 and 92,000), respectively, on the other. In the native gels the enzymes migrated as dimers: for muscle phosphorylase a, a tetramer was also observed. The a and b forms of the enzymes could not be resolved. An antibody raised against rat liver phosphorylase reacted only with the liver enzyme, whereas an antibody raised against brain phosphorylase stained the brain enzyme and the enzymes from MH 3924A and C1I cells. This indicates that hepatoma cells and immortalized nontumorigenic epithelial liver cells express a phosphorylase isoenzyme that is different from the liver type but similar to the brain type. The PhastSystem provides a rapid, sensitive, and highly reproducible method to resolve the different isoenzymes of glycogen phosphorylase. PMID:2070785

Mayer, D; Letsch, I

1991-04-01

29

Method for the detection and differentiation of cellulase components in polyacrylamide gels  

Microsoft Academic Search

Endoglucanase and exoglucanase components of cellulase can be detected and differentiated after polyacrylamide gel electrophoresis by performing activity stains. Endoglucanase activity was visualized in carboxymethyl cellulose agar replicas of gels by staining with Congo red. General ..beta..-1,4-glucanase activity was located by soaking the gel in a solution of NaBHâ-reduced cellulo-oligosaccharides, and detecting the formation of reducing sugars by reaction with

T. D. Bartley; K. Murphy-Holland; D. E. Eveleigh

1984-01-01

30

Improved conditions for silver-ammonia staining of DNA in polyacrylamide gel.  

PubMed

An improved silver-ammonia staining method for DNA on polyacrylamide gels is described. In this method, staining of DNA using silver-ammonia complex allows high sensitivity, low cost, low toxicity, and simple protocol without requiring fixation and sensitization steps. The protocol takes less than 40 min to complete, with a detection limit of 1.5 pg of single DNA band on polyacrylamide gels, approximately 30-fold higher than that of original silver-ammonia staining method. Furthermore, this novel technique not only exhibits high sensitivity for large DNA fragment, but also shows a better trend to detect low-base-pair DNA compared with other silver staining methods. PMID:20411569

Cong, Wei-Tao; He, Hong-Zhang; Zhu, Zhong-Xin; Ye, Cai-Xue; Yang, Xu-Yi; Choi, Jung-Kap; Jin, Li-Tai; Li, Xiao-Kun

2010-05-01

31

Molecular sequestration stabilizes CAP-DNA complexes during polyacrylamide gel electrophoresis.  

PubMed Central

The gel electrophoresis mobility shift assay is widely used for qualitative and quantitative characterization of protein complexes with nucleic acids. Often it is found that complexes that are short-lived in free solution (t1/2 of the order of minutes) persist for hours under the conditions of gel electrophoresis. We have investigated the influence of polyacrylamide gels on the pseudo first-order dissociation kinetics of complexes containing the E.coli cyclic AMP receptor protein (CAP) and lactose promoter DNA. Within the gel matrix, kdiss decreased with increasing [polyacrylamide] and the order of the reaction was changed. In free solution, kdiss was proportional to [DNA]2, while in 5% gels, kdiss was proportional to [DNA]0.3. In gels of [polyacrylamide] > or = 10%, kdiss was nearly independent of [DNA] until fragment concentrations exceeded 0.1 microM. Even in the absence of competing DNA, kdiss(gel) < kdiss(solution). These results suggest that the lifetime of CAP-DNA complexes in free solution is limited by their encounter frequency with molecules of DNA or with protein-DNA complexes; some or all of the stabilization observed in gels may be due to a reduction in this frequency. Images

Fried, M G; Liu, G

1994-01-01

32

Two-Dimensional Polyacrylamide Gel Analysis of Plodia interpunctella Granulosis Virus †  

PubMed Central

The structural polypeptides of purified Plodia interpunctella granulosis virus were analyzed by three different two-dimensional gel systems. Isoelectric focusing followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis allowed resolution of 53 acidic polypeptides in the enveloped nucleocapsid of the virus ranging in molecular weight from 97,300 to 8,000. Nine of these polypeptides were shown to be glycoproteins by the technique of radiolabeled lectin blotting. Separation of the granulin in this system allowed resolution of five species, all of which have identical tryptic peptide maps. This matrix protein was demonstrated to be a phosphoglycoprotein by radiolabeled lectin blotting and acid phosphatase dephosphorylation. Nonequilibrium pH gel electrophoresis followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis allowed resolution of the major basic protein of the virus, VP12, from a more acidic protein of the same molecular weight. Tryptic peptide analysis demonstrated that these two proteins were indeed different and acid urea gels followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis allowed localization of the acidic protein to the envelope and the basic protein to the nucleocapsid of the virus. Finally, probing of the separated envelope nucleocapsid proteins in both the isoelectric focusing and nonequilibrium pH gel electrophoresis two-dimensional systems after transfer to nitrocellulose with iodinated, purified viral proteins allowed further insight into reactions which may be important in the maintenance of the virion structure. Images

Russell, Darcy L.; Consigli, Richard A.

1986-01-01

33

Two-dimensional polyacrylamide gel electrophoresis of extracellular soybean pathogenesis-related proteins using PhastSystem.  

PubMed

Acidic and basic pathogenesis-related proteins (PR-Ps) were extracted from the intercellular fluid (IF) of soybean leaves, locally infected with tobacco necrosis virus and showing necrotic local lesions. Proteins were detected by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) using PhastSystem and precast commercially available gels. Extracts from healthy leaves were run as controls. PR-Ps were first run under native PAGE conditions or isoelectric focusing (IEF), the gels stained with Coomassie Blue, then run under sodium dodecyl sulfate (SDS)-denaturing conditions and finally stained with silver. Ten major acidic PR-Ps were separated; their Mr's were close to those found by conventional PAGE. Their isoelectric points ranged from 3.5 to 5.0. Ten basic PR-Ps were separated and their Mr's estimated. None of these acidic or basic soybean PR-Ps was a glycoprotein. PAGE with PhastSystem and precast gels gives reliable results, comparable with those from conventional 2D-PAGE, with simpler experimental procedures. By electrophoresing Coomassie-stained gels with SDS in the second dimension, we were able to control the first-dimensional separation and to avoid laborious protocols generally adopted with unstained gels. PMID:2318193

Roggero, P; Pennazio, S

1990-01-01

34

Lactic acid fermentation by cells of Lactobacillus rhamnosus immobilizedin polyacrylamide gel  

Microsoft Academic Search

Summary  The process of lactic acid fermentation of lactose to lactic acid by Lactobacillus rhamnosus ATCC 7469 has been studied. The following processes have been explored: growth kinetics, as well as lactose utilization,\\u000a production of lactic acid and further degradation of lactic acid. The immobilization experiments were conducted with microbial\\u000a cells entrapped in polyacrylamide gels. Gels with different ratios of the

Kaloyan K. Petrov; Dragomir S. Yankov; Venko N. Beschkov

2006-01-01

35

The reproducibility of polyacrylamide gel dosimetry applied to stereotactic conformal radiotherapy  

Microsoft Academic Search

The reproducibility of polyacrylamide gel (PAG) dosimetry has been evaluated when used to verify two radiotherapy treatment plans of increasing complexity. The plans investigated were a three-field coplanar arrangement, using the linac jaws for field shaping, and a four-field, conformal, non-coplanar plan using precision-cast lead alloy shielding blocks. Each treatment was performed three times using phantoms and calibration gels manufactured

V. P. Cosgrove; P. S. Murphy; M. McJury; E. J. Adams; A. P. Warrington; M. O. Leach; S. Webb

2000-01-01

36

Direct Detection of Labeled Immunoprecipitates and Co-Immunoprecipitates Within a Polyacrylamide Gel  

Microsoft Academic Search

Immunoprecipitation is routinely used to isolate low abundance antigens from complex samples. Immunoprecipitated proteins are separated by SDS-PAGE and stained for total protein, or transferred to a membrane for Western blot analysis. Here, we describe a method for detecting pre-labeled immunoprecipitated proteins directly within a polyacrylamide gel. The procedure requires that antigens within the sample be derivatized with small tags,

Pauli Undesser; Brian D. Wolf; Boguslawa Dworecki; Surbhi Desai; Peter A. Bell

37

One-dimensional SDS-polyacrylamide gel electrophoresis (1D SDS-PAGE).  

PubMed

This protocol describes a denaturing polyacrylamide gel system utilizing sodium dodecyl sulfate (SDS) to separate protein molecules based on size as first described by Laemmli (1970). SDS-PAGE can be used to monitor protein purifications, check the purity of samples, and to estimate molecular weights for unknown proteins. PMID:24674069

Brunelle, Julie L; Green, Rachel

2014-01-01

38

Rheology and morphology of pristine graphene/polyacrylamide gels.  

PubMed

Enhancement of toughness in nanomaterial-based hydrogels is a critical metric for many of their engineering applications. Pristine graphene-polyacrylamide (PAM) hydrogels are synthesized via in situ polymerization of acrylamide monomer in PAM-stabilized graphene dispersion. In-situ polymerization leads to the uniform dispersion of the graphene sheets in the hydrogel. The graphene sheets interact with the elastic chains of the hydrogel through physisorption and permit gelation in the absence of any chemical cross-linker. This study represents the first report of pristine graphene as a physical cross-linker in a hydrogel. The properties of the graphene-polymer hydrogel are characterized by rheological measurements and compressive tests, revealing an increase in the storage modulus and toughness of the hydrogels compared to the chemically cross-linked PAM analogues. The physically cross-linked graphene hydrogels also exhibit self-healing properties. These hydrogels prove to be efficient precursors for graphene-PAM aerogels with enhanced electrical conductivity and thermal stability. PMID:23915342

Das, Sriya; Irin, Fahmida; Ma, Lan; Bhattacharia, Sanjoy K; Hedden, Ronald C; Green, Micah J

2013-09-11

39

A method for the detection and differentiation of cellulase components in polyacrylamide gels.  

PubMed

Endoglucanase and exoglucanase components of cellulase can be detected and differentiated after polyacrylamide gel electrophoresis by performing activity stains. Endoglucanase activity was visualized in carboxymethyl cellulose agar replicas of gels by staining with Congo red. General beta-1,4-glucanase activity was located by soaking the gel in a solution of NaBH4-reduced cellulooligosaccharides, and detecting the formation of reducing sugars by reaction with triphenyl tetrazolium chloride. Endoglucanases are active in both assays, while exoglucanases can be distinguished by their activity in the cellulo-oligosaccharide assay only. This methodology has facilitated the purification and characterization of cellulase components from Trichoderma reesei and Microbispora bispora. PMID:6207744

Bartley, T D; Murphy-Holland, K; Eveleigh, D E

1984-07-01

40

Using in situ rheology to characterize the microstructure in photopolymerized polyacrylamide gels for DNA electrophoresis.  

PubMed

Photopolymerized cross-linked polyacrylamide hydrogels are attractive sieving matrix formulations for DNA electrophoresis owing to their rapid polymerization times and the potential to locally tailor the gel pore structure through spatial variation of illumination intensity. This capability is especially important in microfluidic systems, where photopolymerization allows gel matrices to be precisely positioned within complex microchannel networks. Separation performance is also directly related to the nanoscale gel pore structure, which is in turn strongly influenced by polymerization kinetics. Unfortunately, detailed studies of the interplay among polymerization kinetics, mechanical properties, and structural morphology are lacking in photopolymerized hydrogel systems. In this paper, we address this issue by performing a series of in situ dynamic small-amplitude oscillatory shear measurements during photopolymerization of cross-linked polyacrylamide electrophoresis gels to investigate the relationship between rheology and parameters associated with the gelation environment including UV intensity, monomer and cross-linker composition, and reaction temperature. In general, we find that the storage modulus G' increases with increasing initial monomer concentration, cross-linker concentration, and polymerization temperature. The steady-state value of G', however, exhibits a more complex dependence on UV intensity that varies with gel concentration. A simple model based on rubber elasticity theory is used to obtain estimates of the average gel pore size that are in surprisingly good agreement with corresponding data obtained from analysis of DNA electrophoretic mobility in gels cast under identical polymerization conditions. PMID:16892481

Wang, Jian; Ugaz, Victor M

2006-09-01

41

Experimental properties of THPC based normoxic polyacrylamide gels for use in x-ray computed tomography gel dosimetry  

Microsoft Academic Search

The aim of the present study is to investigate the effects of tetrakis(hydroxymethyl)phosphonium chloride (THPC) on the experimental properties of normoxic polyacrylamide gels. Specifically we: (1) assess the use of THPC as an anti-oxidant for x-ray CT PAGAT dosimetry by investigating dose response reproducibility and stability, and optimal THPC concentration for maximum dose sensitivity while ensuring no O2 inhibition; (2)

A Jirasek; M Hilts; C Shaw; P Baxter

2006-01-01

42

Rapid Separation and Quantification of Major Caseins and Whey Proteins of Bovine Milk by Polyacrylamide Gel Electrophoresis  

Microsoft Academic Search

A rapid polyacrylamide gel electro- phoretic method was developed for separating and quantifying major pro- teins in casein and whey protein fractions of bovine milk. For casein separation, best results were achieved by an 8% poly- acrylamide gel containing 4 M urea and a top layer of large pore sample gel; for whey protein the most_ satisfactory separation was with

K. F. Ng-Kwai-Hang; E. M. Kroeker

1984-01-01

43

Ribosomal Ribonucleic Acids of Cultured Cells: a Preliminary Survey of Differences among Mammalian Species Detectable by Polyacrylamide Gel Electrophoresis.  

National Technical Information Service (NTIS)

Ribosomal ribonucleic acids (rRNA's) of cultured cells from various species were compared by polyacrylamide gel electrophoresis. Electrophoretic mobility of the 28 S RNA component varied according to species. Human cell 28 S rRNA was distinguishable from ...

M. E. Soergel F. L. Schaffer

1972-01-01

44

A direct method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels  

PubMed Central

Background In vertebrates, two types of cholinesterases exist, acetylcholinesterase and butyrylcholinesterase. The function of acetylcholinesterase is to hydrolyse acetylcholine, thereby terminating the neurotransmission at cholinergic synapse, while the precise physiological function of butyrylcholinesterase has not been identified. The presence of cholinesterases in tissues that are not cholinergically innervated indicate that cholinesterases may have functions unrelated to neurotransmission. Furthermore, cholinesterases display a genuine aryl acylamidase activity apart from their predominant acylcholine hydrolase activity. The physiological significance of this aryl acylamidase activity is also not known. The study on the aryl acylamidase has been, in part hampered by the lack of a specific method to visualise this activity. We have developed a method to visualise the aryl acylamidase activity on cholinesterase in polyacrylamide gels. Results The o-nitroaniline liberated from o-nitroacetanilide by the action of aryl acylamidase activity on cholinesterases, in the presence of nitrous acid formed a diazonium compound. This compound gave an azo dye complex with N-(1-napthyl)-ethylenediamine, which appeared as purple bands in polyacrylamide gels. Treating the stained gels with trichloroacetic acid followed by Tris-HCl buffer helped in fixation of the stain in the gels. By using specific inhibitors for acetylcholinesterase and butyrylcholinesterase, respectively, differential staining for the aryl acylamidase activities on butyrylcholinesterase and acetylcholinesterase in a sample containing both these enzymes has been demonstrated. A linear relationship between the intensity of colour developed and activity of the enzyme was obtained. Conclusions A novel method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels has been developed.

Jaganathan, Lakshmanan; Boopathy, Rathanam

2000-01-01

45

Adhesion of chicken hepatocytes to polyacrylamide gels derivatized with N-acetylglucosamine.  

PubMed

Complex carbohydrates on the surfaces of eukaryotic cells are thought to participate in a wide variety of cell-cell interactions. A model system has therefore been developed to study these processes. In the present experiments, the ability of chicken hepatocytes to recognize and adhere to sugars covalently linked to polyacrylamide gels was investigated. The gels were snythesized by two methods. Type I gels were prepared from a co-polymer of an active ester of acrylic acid (N-succinimidyl acrylate), acrylamide, and bisacrylamide. The "activated" polyacrylamide gel was then treated with the desired ligand containing an amino group, such as 6-aminohexyl O- or S-glycoside. Type II gels were formed by treating similar ligands with acryloyl chloride, followed by co-polymerization of the resulting N-substituted acrylamide with acrylamide and N,N'-methylenebisacrylamide. These polyacrylamide derivatives offer many advantages for studies with intact cells. They are not toxic to any cell type studied, can be cast in any desired shape, are transparent and stable over a wide range of pH values, and contain no cationic and low to negligible levels of anionic charge (charged groups can be introduced if desired), and the polyacrylamide matrix is stable to common biological agents such as bacteria and enzymes. In addition, type I gels can be synthesized using a broad range of molecules containing amino groups, such as glycopeptides, proteins, etc. The hepatocytes were prepared by collagenase perfusion of intact chicken livers. The rate and extent of adhesion of the cells to the derivatized gels was determined by measuring lactate dehydrogenase in these cells. This enzyme was also used to assay viability and cell "leakiness." At 37 degrees C, 70 to 100% of the cells adhered within 60 min to gels derivatized with N-acetylglucosamine, i.e. gels derivatized with 6-aminohexyl 2-acetamido-2-deoxy-beta-D-glucopyranoside (or the corresponding thioglycoside). By contrast, less than 5% of the cells adhered to polyacrylamide or to gels derivatized with 6-aminohexanol or the 6-aminohexyl glycosides of beta-D-glucose, beta-D-galactose, alpha-D-mannose, beta-D-maltose, beta-D-melibiose, beta-D-cellobiose, and (alpha or beta)-D-lactose. Kinetic studies with the chicken hepatocytes and N-acetylglucosamine gels showed that cell-gel binding was dependent upon Ca2+ and was decreased at low temperatures. Binding was inhibited by N-acetylglucosamine or by glycosides of this sugar, the most effective inhibitor being orosomucoid (alpha1-acid glycoprotein) pretreated with sialidase and beta-galactosidase. The cell surface receptor(s) involved in this interaction is not known, but may be related or identical to the chicken liver binding protein described by Lunney and Ashwell (Lunney, J., and Ashwell, G. (1976) Proc. Natl. Acad. Sci. U. S. A. 73, 341--343). The present results suggest that this model system should prove useful in delineating cell surface interactions with carbohydrates. PMID:701294

Schnaar, R L; Weigel, P H; Kuhlenschmidt, M S; Lee, Y C; Roseman, S

1978-11-10

46

Proton Diffusion and T1Relaxation in Polyacrylamide Gels: A Unified Approach Using Volume Averaging  

NASA Astrophysics Data System (ADS)

The structure of polyacrylamide gels was studied using proton spin-lattice relaxation and PFG diffusion methods. Polyacrylamide gels, with total polymer concentrations ranging from 0.25 to 0.35 g/ml and crosslinker concentrations from 0 to 10% by weight, were studied. The data showed no effect of the crosslinker concentration on the diffusion of water molecules. The Ogston-Morris and Mackie-Meares models fit the general trends observed for water diffusion in gels. The diffusion coefficients from the volume averaging method also fit the data, and this theory was able to account for the effects of water-gel interactions that are not accounted for in the other two theories. The averaging theory also did not require the physically unrealistic assumption, required in the other two theories, that the acrylamide fibers are of similar size to water molecules. Contrary to the diffusion data, T1relaxation measurements showed a significant effect of crosslinker concentration on the relaxation of water in gels. The model developed using the Bloch equations and the volume averaging method described the effects of water adsorption on the gel medium on both the diffusion coefficients and the relaxation measurements. In the proposed model the gel medium was assumed to consist of three phases (i.e., bulk water, uncrosslinked acrylamide fibers, and a bisacrylamide crosslinker phase). The effects of the crosslinker concentration were accounted for by introducing the proton partition coefficient, Keq, between the bulk water and crosslinker phase. The derived relaxation equations were successful in fitting the experimental data. The partition coefficient, Keq, decreased significantly as the crosslinker concentration increased from 5 to 10% by weight. This trend is consistent with the idea that bisacrylamide tends to form hydrophobic regions with increasing crosslinker concentration.

Penke, Brigita; Kinsey, Stephen; Gibbs, Stephen J.; Moerland, Timothy S.; Locke, Bruce R.

1998-06-01

47

Detection of calcium binding proteins on polyacrylamide gels using time-resolved lanthanide luminescence photography.  

PubMed

Methods were developed for using the luminescent lanthanides Tb3+ and Eu3+ for the specific staining of calcium-binding proteins, as well as the nonspecific staining of proteins, on polyacrylamide gels. These methods involve equilibration of the gel after electrophoresis in solutions containing the appropriate lanthanide and a weak competitive chelating agent, such as N-(2-hydroxyethyl)iminodiacetic acid or nitrilotriacetic acid. This staining has the potential for complete reversibility using stronger chelating agents such as EDTA or diethylenetriaminepentaacetic acid, to allow for recovery of the protein. Specific staining produces an intense luminescent signal from those metal-binding proteins which have been modified either chemically or via site-directed mutagenesis. Gels were photographed using a time-resolved fluorescence camera system. PMID:7513974

Hill, I E; Hogue, C W; Clark, I D; MacManus, J P; Szabo, A G

1994-02-01

48

A rapid 3% polyacrylamide slab gel electrophoresis method for high through put screening of LDL phenotype  

PubMed Central

Background Small dense LDL is reported to be associated with increased coronary artery disease risk by various epidemiological studies. The gold standard for separation and identification of LDL subtypes in plasma is ultracentrifugation which is a lengthy procedure and difficult to perform. Various other methods like NMR, HPLC, gradient gel electrophoresis (GGE) have been reported for LDL sub fractionation all of which require specialized equipments and expertise. We report here a high throughput 3% polyacrylamide slab gel electrophoresis method (PASGE) for sub fractionation of LDL which was compared with GGE, a commonly used method for LDL sub fractionation. Results The 3% PASGE method compared well with the GGE method There was a good correlation between LDL particle diameter identified by the PASGE and GGE (Pearson correlation coefficient = 0.950). A 100% concordance was found when samples were classified as per LDL phenotypes in subjects with A and B phenotype by the two methods with the concordance being 66% in subjects with intermediate (I) phenotype. The electrophoresis apparatus was optimized and designed for running twenty eight samples at a time compared to twelve to fourteen by the conventional PASGE and eight to twelve by disc electrophoresis. Conclusion The rapid 3% polyacrylamide slab gel electrphoresis method developed is simple to perform, cost-effective and can be used for the identification LDL sub fractionation and phenotyping in large epidemiological studies.

Singh, Yogendra; Lakshmy, Ramakrishnan; Gupta, Ruby; Kranthi, Vemparala

2008-01-01

49

Fourier transform Raman spectroscopy of polyacrylamide gels (PAGs) for radiation dosimetry  

NASA Astrophysics Data System (ADS)

Polyacrylamide gels (PAGs) are used for magnetic resonance imaging radiation dosimetry. Fourier transform (FT) Raman spectroscopy studies were undertaken to investigate cross-linking changes during the copolymerization of polyacrylamide gels in the spectral range of 200-3500 . Vibrational bands of 1285 and 1256 were assigned to acrylamide and bis-acrylamide single binding modes. Bands were found to decrease in amplitude with increasing absorbed radiation dose as a result of copolymerization. Principal component regression was performed on FT-Raman spectra of PAG samples irradiated to 50 Gy. Two components were found to be sufficient to account for 98.7% of the variance in the data. Cross validation was used to establish the absorbed radiation dose of an unknown PAG sample from the FT-Raman spectra. The calculated correlation coefficient between measured and predictive samples was 0.997 with a standard error of estimate of 0.976 and a standard error of prediction of 1.140. Results demonstrate the potential of FT-Raman spectroscopy for ionizing radiation dosimetry using polyacrylamide gels.

Baldock, C.; Rintoul, L.; Keevil, S. F.; Pope, J. M.; George, G. A.

1998-12-01

50

Evaluation of total protein content in tears of dogs by polyacrylamide gel disk electrophoresis.  

PubMed

Concentration of total proteins was measured and sodium dodecyl sulfate-polyacrylamide gel disk electrophoresis was performed on tear and plasma samples obtained from 26 healthy dogs, and the results were compared. Mean +/- SEM concentration of total proteins in tears was 0.63 +/- 0.04 g/dl, and significant effects of age or gender were not found. The protein composition of tears in dogs was complex, and bands from light and heavy chains of immunoglobulins were identified by electrophoresis. PMID:1586012

Barrera, R; Jiménez, A; López, R; Mañé, M C; Rodríguez, J F; Molleda, J M

1992-04-01

51

A Novel Technique for Micro-patterning Proteins and Cells on Polyacrylamide Gels  

PubMed Central

Spatial patterning of proteins (extracellular matrix, ECM) for living cells on polyacrylamide (PA) hydrogels has been technically challenging due to the compliant nature of the hydrogels and their aqueous environment. Traditional micro-fabrication process is not applicable. Here we report a simple, novel and general method to pattern a variety of commonly used cell adhesion molecules, i.e. Fibronectin (FN), Laminin (LN) and Collagen I (CN), etc. on PA gels. The pattern is first printed on a hydrophilic glass using polydimethylsiloxane (PDMS) stamp and micro-contact printing (?CP). Pre-polymerization solution is applied on the patterned glass and is then sandwiched by a functionalized glass slide, which covalently binds to the gel. The hydrophilic glass slide is then peeled off from the gel when the protein patterns detach from the glass, but remain intact with the gel. The pattern is thus transferred to the gel. The mechanism of pattern transfer is studied in light of interfacial mechanics. It is found that hydrophilic glass offers strong enough adhesion with ECM proteins such that a pattern can be printed, but weak enough adhesion such that they can be completely peeled off by the polymerized gel. This balance is essential for successful pattern transfer. As a demonstration, lines of FN, LN and CN with widths varying from 5–400 ?m are patterned on PA gels. Normal fibroblasts (MKF) are cultured on the gel surfaces. The cell attachment and proliferation are confined within these patterns. The method avoids the use of any toxic chemistry often used to pattern different proteins on gel surfaces.

Tang, Xin; Ali, M. Yakut; Saif, M. Taher A.

2012-01-01

52

Investigation of tetrakis hydroxymethyl phosphonium chloride as an antioxidant for use in x-ray computed tomography polyacrylamide gel dosimetry  

Microsoft Academic Search

Of the antioxidants used to scavenge oxygen in polymer gel dosimeters, tetrakis (hydroxymethyl) phosphonium chloride (THPC) has been shown to hold great promise due to its rapid oxygen scavenging abilities. In this study we (a) investigate the use of THPC as an antioxidant for polyacrylamide gel (PAGAT) dosimeters used in conjunction with x-ray computed tomography (CT) and (b) work to

A. Jirasek; M. Hilts; C. Shaw; P. Baxter

2006-01-01

53

Characterization of protein variants and post-translational modifications: ESI-MSn analyses of intact proteins eluted from polyacrylamide gels  

Microsoft Academic Search

We have developed a strategy to characterize protein isoforms, resulting from single-point mutations and post- translational modifications. This strategy is based on polyacrylamide gel electrophoresis separation of protein isoforms, mass spectrometry (MS) and MSn analyses of intact proteins, and tandem MS analyses of proteolytic peptides. We extracted protein isoforms from polyacryl- amide gels by passive elution using SDS, followed by

Stephane Claverol; Odile Burlet-Schiltz; Jean Edouard Gairin; Bernard Monsarrat

2003-01-01

54

Partitioning and diffusion of proteins and linear polymers in polyacrylamide gels.  

PubMed Central

The equilibrium partition coefficient (K) and diffusion coefficient (Dgel) of two proteins and two linear polymers were measured as a function of polymer content of a 2.7% cross-linked polyacrylamide (PA) gel. The gel concentration, expressed as a volume percentage of PA in the gel (phi), varied between 0 and 14%. The measurements were made by fluorescence spectroscopy; fluorescent dyes were covalently attached to the macromolecules. The dependence of K on phi for the proteins agrees with a model of the gel network as randomly placed, impenetrable rods. The diffusion data are interpreted in terms of an effective medium theory for the mobility of a sphere in a Brinkman fluid. Using values of the Brinkman parameter in the literature, the effective medium model with no adjustable parameters fits the diffusion data for the proteins very well but underpredicts Dgel for the linear polymers. The gel effect on partitioning is significantly greater than that on diffusion. The permeability (KDgel) of bovine serum albumin decreased by 10(3) over the range phi = 0 --> 8%, and the ratio of permeabilities for ribonuclease compared to BSA increased from 2 to 30. Images FIGURE 1

Tong, J; Anderson, J L

1996-01-01

55

MALDI analysis of proteins after extraction from dissolvable ethylene glycol diacrylate cross-linked polyacrylamide gels.  

PubMed

Although the extraction of intact proteins from polyacrylamide gels followed by mass spectrometric molecular mass determination has been shown to be efficient, there is room for alternative approaches. Our study evaluates ethylene glycol diacrylate, a cleavable cross-linking agent used for a new type of dissolvable gels. It attains an ester linkage that can be hydrolyzed in alkali conditions. The separation performance of the new gel system was tested by 1D and 2D SDS-PAGE using the outer chloroplast envelope of Pisum sativum as well as a soluble protein fraction of human lymphocytes, respectively. Gel spot staining (CBB), dissolving, and extracting were conducted using a custom-developed workflow. It includes protein extraction with an ammonia-SDS buffer followed by methanol treatment to remove acrylamide filaments. Necessary purification for MALDI-TOF analysis was implemented using methanol-chloroform precipitation and perfusion HPLC. Both cleaning procedures were applied to several standard proteins of different molecular weight as well as 'real' biological samples (8-75 kDa). The protein amounts, which had to be loaded on the gel to detect a peak in MALDI-TOF MS, were in the range of 0.1 to 5 ?g, and the required amount increased with increasing mass. PMID:23775326

Papasotiriou, Dimitrios G; Markoutsa, Stavroula; Gorka, Jan; Schleiff, Enrico; Karas, Michael; Meyer, Bjoern

2013-09-01

56

Characterisation of soil-bound residue fractions of the fungicide dithianon by gel permeation chromatography and polyacrylamide gel electrophoresis.  

PubMed

The degradation of the (14)C-labelled fungicide dithianon in an orthic luvisol was investigated under standardized conditions in comparison to stimulated microbial activity by an amendment of maize straw. The compound is characterized by mineralization losses of approximately 33% and the formation of non-extractable bound residues of approximately 63% in 64 days. Despite the major role of microorganisms in mineralizing this compound, the formation of bound residues is not biotically induced. Gel permeation chromatography and polyacrylamide gel electrophoresis, as different size separation techniques of the humic acids fractions, showed differences in the distribution patterns of non-extractable residues depending on the addition of straw material. The results presented support the existence of humic substances in soil as a micellar system rather than as a biopolymer. PMID:15092966

Wanner, U; Burauel, P; Führ, F

2000-04-01

57

Evaluation of proteinuria by two-dimensional polyacrylamide gel electrophoresis after kidney transplantation.  

PubMed

Urinary proteins were studied in patients after kidney transplantation during various functional states (normal function, acute rejection, chronic rejection) by two-dimensional polyacrylamide gel electrophoresis. In the first dimension, the proteins were separated according to their electric charge by isoelectric focusing, and in the second dimension according to their molecular weight by sodium dodecyl sulfate polyacrylamide gel electrophoresis. After electrophoresis the proteins were visualized using a highly sensitive silver stain technique. The combination of these methods allowed the discrimination of up to 250 protein spots in human urine, most of them unidentified up to now. Functional changes of the kidney transplants were accompanied by complex changes of the protein pattern in urine. These changes cannot be simply compared to the tubular and glomerular pattern of proteinuria which can be identified by one-dimensional sodium dodecyl sulfate electrophoresis. The 2D electrophoresis of urinary proteins may develop into a useful tool in localizing of kidney damage and in the evaluation of renal disease. PMID:3915927

Bauer, H; Nagel, J; Wierer, D; Brunner, H; Franz, H E

58

C-terminal sequencing method for proteins in polyacrylamide gel by the reaction of acetic anhydride.  

PubMed

A successive C-terminal amino acid truncation reaction with acetic anhydride was applied on proteins in polyacrylamide gel. Protein bands separated by conventional SDS-PAGE were excised, partially fixed in the gel with glutaraldehyde ethanol solution, dehydrated with ACN and subjected to the truncation reaction with acetic anhydride formamide solution. Pre-treatment of the gel with pyridine aqueous solution was found to enhance the truncation reaction yields. After the truncation reaction, the products were treated with an aqueous solution of dimethylaminoethanol to hydrolyze oxazolone rings at the C termini of the truncated products and O-acetylated products of serine, threonine and/or tyrosine. Several commercially available proteins of 10-40 kDa, as determined by SDS-PAGE, such as myoglobin, trypsin inhibitor, alpha-hemolysin, cytochrome c, chymotrypsin C chain, elastase, acylase and histone H4, were subjected to the C-terminal analysis. The truncated proteins were in-gel digested with trypsin and the extracted peptides were analyzed by MALDI-TOF MS, giving rise to a series of molecular mass ions of the C-terminal truncated fragments corresponding to the C-terminal amino acid sequence of the relevant protein. PMID:16552787

Miyazaki, Kenji; Tsugita, Akira

2006-04-01

59

Polyacrylamide Gel Identification of Bacterial L-Forms and Mycoplasma Species of Human Origin  

PubMed Central

Polyacrylamide gel electrophoretic patterns of acidified phenol extracts prepared from whole cells can be used for the identification of bacterial L-forms and Mycoplasma species of human origin. Ten human Mycoplasma serotypes and eight L-forms belonging to five different genera were studied. The gel patterns were sufficiently distinct and reproducible that it was possible not only to identify L-forms at the genus level (group with streptococci) and different Mycoplasma serotypes but also to differentiate between the two of them. The parentage of L-forms of Streptobacillus moniliformis L1, Listeria monocytogenes, Streptococcus MG, and Staphylococcus aureus Smith strain was established by relating their gel patterns directly to parent bacteria. It was found that an L-form designated S. moniliformis An (ATCC 14220) was actually an L-form of Proteus. In addition, it was shown electrophoretically that no relationship existed between the Streptococcus MG L-form and M. pneumoniae. The applicability of this method as a diagnostic and taxonomic tool for the differentiation of L-forms and mycoplasmas is discussed. Images

Theodore, Theodore S.; Tully, Joseph G.; Cole, Roger M.

1971-01-01

60

Delayed Gel Indurations as an Adverse Effect of Polyacrylamide Filler and Its Easy Treatment  

PubMed Central

Background. The more increasing use of permanent soft tissue fillers such as polyacrylamide hydrogel (PAAG) for aesthetic purposes, the more adverse events resulting from them are reported. Occasionally, nonserious complications and misdiagnosis result in unnecessary surgeries and sequels. Objective. To introduce delayed gel indurations (DGIs) as a late onset complication of PAAG and its easy treatment. Patient and Methods. Twenty patients (17 females and 3 males) referred to us with subcutaneous mass at injected site of PAAG. We diagnosed DGI based on clinical and sonography findings and treatment was performed with a hole by 16-gauge needle and squeezing. Results. From 20 patients with 21 cases of DGI, 5 (23.8%), 5 (23.8%), and 5 (23.8%) cases in cheeks, glabella, and lips were seen, respectively. The time range between PAAG injection and presentation of patients was 10–28 months (mean = 17.5%). All of the patients responded very well to treatment without recurrence and any complications. Conclusion. DGI is a nonserious, late onset, and easily treated complication of PAAG that is probably induced due to water exchange between gel and surrounding tissue and modest host immune reaction to gel.

Kavoussi, Hossein; Ebrahimi, Ali

2012-01-01

61

Phosphoprotein staining for sodium dodecyl sulfate-polyacrylamide gel electrophoresis using fluorescent reagent morin hydrate.  

PubMed

A fluorescence-based stain with 3,5,7,2',4'-pentahydroxyflavone (morin hydrate, MH) was designed to stain phosphoproteins in one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Al(3+) was applied as a "fixed bridge," providing an efficient energy transfer channel between phosphoprotein and MH, to produce a strong fluorescent complex for the determination of phosphoprotein. As little as 62.5ng of ?-casein (7 or 8 phosphates) and ?-casein (5 phosphates), 125ng of ovalbumin (2 phosphates), and ?-casein (1 phosphate) could be visualized with a wide linear dynamic range. In comparison with conventional methods, MH stain is a time-saving method that takes just 90min. It also has good compatibility with routine protein stainings such as Coomassie Brilliant Blue R (CBBR) and SYPRO Ruby for total protein analysis. PMID:23274386

Wang, Xu; Hwang, Sun-Young; Cong, Wei-Tao; Jin, Li-Tai; Choi, Jung-Kap

2013-04-01

62

[Comparative studies of avian mycoplasmas by flat gel polyacrylamide electrophoresis (author's transl)].  

PubMed

The phenol-acetic-acid extraced cell proteins of Mycoplasma (M.) and Acholeplasma (A.) reference strains (PG31 (M. gallisepticum), PG 16 (M. gallinarum), PG30 (M iners), 17529 (M. meleagridis), WVU 1853 (M. synoviae), 1340 (M. anatis), PG8 and PG9 (A. laidlawii), CKK (Serovar C), DD (Serovar D), WR1 (Serogroup F), 695 (Serogroup I) and 694 (Serogroup L) were anlysed by the flat gel polyacrylamide electrophoresis. With exception of PG8 and PG9 the Coomassie Blue-stained protein patterns show that each of the strains produced reproducible characteristic electrophoretic pattern by which the reference strains could be differentiated. However, before the question could be answered whether the procedure described is suitable to replace the serological species differentiation of avian mycoplasmas, serological and electrophoretic studies of a relevant number of field strain are necessary. PMID:566006

Hinz, K H; Neumann, U

1978-04-01

63

Fingerprinting of signal transduction pathways using a combination of anti-phosphotyrosine immunoprecipitations and two-dimensional polyacrylamide gel electrophoresis.  

PubMed

Virtually all known cellular processes involve modulation of cellular signaling pathways via changes in protein phosphorylation. With genomics efforts more than doubling the number of proteins available for analysis, a major challenge will be to identify unknown phosphoproteins as they exist in the normal or diseased intracellular environment. Recent advances in proteomic technology have made it possible to examine changes in protein expression with much greater resolution than was previously possible. In this report, we describe a rapid and reproducible method for identifying phosphoproteins upregulated in response to activation of cell surface receptors. Phosphotyrosine-containing proteins were immunoprecipitated from IFNalpha- or IL2-treated primary human lymphocyte extracts using a novel anti-phosphotyrosine immunoprecipitation technique. This technique takes advantage of differing antibody affinities for epitopes on native versus denatured proteins. Following separation from the immunopellets, phosphoproteins are resolved by two-dimensional polyacrylamide gel electrophoresis. With this method, we identified known proteins phosphorylated in response to IL2 or IFNalpha using both silver staining and Western blotting for protein detection/identification. The silver-stained immunoprecipitation profile serves as a fingerprint for phosphorylation events that occur in response to cytokine treatment. By merging these techniques with mass spectrometric microsequencing, new capabilities are achieved. It will then be possible to identify novel signaling proteins that are activated in response to a variety of stimuli, including receptor activation, disease progression, etc. PMID:11465514

Stancato, L F; Petricoin, E F

2001-06-01

64

Performing Isoelectric Focusing and Simultaneous Fractionation of Proteins on A Rotary Valve Followed by Sodium Dodecyl - Polyacrylamide Gel Electrophoresis  

PubMed Central

In this technical note, we design and fabricate a novel rotary valve and demonstrate its feasibility for performing isoelectric focusing and simultaneous fractionation of proteins, followed by sodium dodecyl – polyacrylamide gel electrophoresis. The valve has two positions. In one position, the valve routes a series of capillary loops together into a single capillary tube where capillary isoelectric focusing (CIEF) is performed. By switching the valve to another position, the CIEF-resolved proteins in all capillary loops are isolated simultaneously, and samples in the loops are removed and collected in vials. After the collected samples are briefly processed, they are separated via sodium dodecyl – polyacrylamide gel electrophoresis (SDS-PAGE, the 2nd-D separation) on either a capillary gel electrophoresis instrument or a slab-gel system. The detailed valve configuration is illustrated, and the experimental conditions and operation protocols are discussed.

Wang, Wei; Lu, Joann J.; Gu, Congying; Zhou, Lei; Liu, Shaorong

2013-01-01

65

Studies on the bioactivity of radioiodinated highly purified bovine thyrotropin: analytical polyacrylamide gel electrophoresis  

SciTech Connect

Highly purified bovine TSH (stored in solution at -70 C) was radioiodinated by the stoichiometric chloroamine-T method. The iodinated material ws subjected to analytical polyacrylamide disc gel electrophoresis. TSH was eluted from gel slices (1 mm width) and was analyzed for radioactivity and bioactivity. The latter was determined using the cultured thyroid cell cAMP response assay. Radioactivity in the TSH preparation migrated separately from bioactivity, but concordant with the protein bands observed in gels run in parallel. Further studies performed on bovine TSH purified in our laboratory, as well as on a different TSH preparation of exceptionally high potency (both stored as lyophilized powder) revealed a different pattern, with TSH bioactivity and radioactivity eluting concurrently. Iodination of TSH did not alter its electrophoretic migration on disc gel electrophoresis. In all preparations polymorphism of TSH bioactivity was observed, with at least four separate protein bands containing TSH bioactivity being present in our preparation. The relationship between the degree of iodination and retention of TSH bioactivity was examined. Incorporation of /sup 125/I into TSH was greatly different at two different concentrations of chloramine-T. Despite this, however, the progressive loss of TSH bioactivity was similar at both concentrations, indicating that incorporation of iodine into the TSH molecule is not itself responsible for the decrease in bioactivity. These studies indicate variability among different TSH preparations in terms of their retention of bioactivity. Significant loss of TSH bioactivity appears to occur during storage in solution. The damage to the biological activity of TSH during the iodination procedure is more likely related to the oxidation process than to the incorporation of iodine.

Takai, N.A.; Filetti, S.; Rapoport, B.

1981-01-01

66

Propagation Velocity and Attenuation of a Shear Wave Pulse Measured by Ultrasound Detection in Agarose and Polyacrylamide Gels  

Microsoft Academic Search

The aim of our research was to measure and analyze phase velocity and pulse attenuation of a shear wave in two media: well-known agarose-gelatin gel and seldom-used polyacrylamide gel. These quantities were determined at three temperatures by the method of transmission sonoelastography described by Catheline et al. (1999). The shear wave was generated with a shaker stimulated by an electric

Tomasz Klinkosz; Czeslaw J. Lewa; Jacek Paczkowski

2008-01-01

67

One and two-dimensional polyacrylamide gel analysis of the heat shock proteins of the virilis group of Drosophila  

Microsoft Academic Search

The heat shock proteins of the virilis group of Drosophila are analyzed by one- and two-dimensional polyacrylamide gel analysis. This group consists of the two closely related but distinct virilis and montana phylads. The analysis reveals that some of the heat shock proteins are highly conserved among the two phylads while others are not. The 83-, 72-, and 69-kdalton proteins

Ralph M. Sinibaldi; Robert V. Storti

1982-01-01

68

Electrophoresis of /sup 35/S-labeled proteoglycans of polyacrylamide-agarose composite gels and their visualization by fluorography  

SciTech Connect

Techniques for the electrophoresis of /sup 35/S-labeled proteoglycans on polyacrylamide-agarose gel slabs and subsequent fixation, impregnation, and fluorography of such electrophoretograms have been developed. The procedure permits the examination of newly synthesized proteoglycan subspecies using a rapid technique, previously unavailable for these labeled molecules.

Carney, S.L.; Bayliss, M.T.; Collier, J.M.; Muir, H.

1986-01-01

69

Agarose and Polyacrylamide Gel Electrophoresis Methods for Molecular Mass Analysis of 5-500 kDa Hyaluronan  

PubMed Central

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

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

2011-01-01

70

A study of electrophoretic mobility of DNA in agarose and polyacrylamide gels.  

PubMed

The aim of this paper is to clarify the mechanism of gel electrophoresis of DNA under constant-field conditions. We have conducted a large number of experiments on double-stranded DNA varying in length between approximately 10 and approximately 50,000 base-pairs, in both agarose and polyacrylamide gels ranging from 0.5% to 12% concentration, and with electric field strengths ranging from 0.5 to 8 V/cm. We have made (logarithmic) plots of velocity against length of DNA for all of the various test conditions. At the left-hand side of these plots, all of the empirical curves have a unique, standard shape. When the curves are normalized so that their left-hand parts coincide, a second feature emerges in that, while for any given test the curve follows the "master curve" up to a certain point, it then "breaks away" and becomes horizontal. We describe these two patterns of behaviour as "regions 1 and 2", respectively. We find simple yet comprehensive empirical formulae that fit the observations in the two regions of behaviour: these express the velocity in terms of length of DNA, electric field strength and gel concentration. We then construct two separate theories for the two regions of behaviour. The first theory involves the statistics of motion of an object through a random array of gel obstacles, with the instantaneous speed depending on the number of obstacles with which the object is currently in contact. The second theory is based on the mechanical hypothesis (for which there is other, independent support) that the DNA moves through the gel by piling up against a barrier, which eventually breaks or deforms under the resulting force, thereby allowing the DNA to move on to the next barrier. The statistical theory is an adaptation of existing work, while the mechanical one is new. We also describe experiments on the migration of repeated-sequence, curved DNA with length up to 1500 base-pairs, and we discuss its behaviour in terms of our two theories. Our studies by electron microscopy are consistent with the view that this repeated-sequence DNA adopts a superhelical configuration. Finally, we show that a very wide range of observations may be understood clearly by means of our two theoretical schemes. PMID:1942040

Calladine, C R; Collis, C M; Drew, H R; Mott, M R

1991-10-01

71

Rapid protein separations in ultra-short microchannels: microchip sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing.  

PubMed

We have developed novel protein gel electrophoresis techniques, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing (IEF) in short microchannels (approximately millimeters) that take less than a minute. A photopatterning technique was used to cast in situ crosslinked polyacrylamide gel in a microchannel to perform SDS-PAGE. A fluorescent protein marker sample (Mr range of 20,000-200,000) was separated in less than 30 s in less than 2 mm of channel length. Crosslinked polyacrylamide gel, patterned in channels using UV light, provides higher sieving power and sample stacking effect, therefore yielding faster and higher-resolution separation in a chip. IEF of proteins was also achieved in a microchannel, and several proteins were focussed within tens of seconds in mm-length channels. As resolution in IEF is independent of separation distance, focusing in ultra-short channels results in not only faster separation but also more concentrated bands potentially allowing detection of low-concentration species. PMID:15499934

Han, Jongyoon; Singh, Anup K

2004-09-17

72

Carbon dioxide adsorption on polyacrylamide-impregnated silica gel and breakthrough modeling  

NASA Astrophysics Data System (ADS)

Polyacrylamide-impregnated silica gel was prepared to capture CO2 from flue gas. The polymerization of acrylamide was carried out in AN solvent using AIBN as initiator and EGDMA as crosslinker. The adsorbents were characterized by N2 adsorption, FTIR analysis, SEM analysis, and thermal gravimetric analysis. The results showed that the polymer was not only occupying the porosity of the silica, but necessarily surrounding silica particles, and the amide groups was successfully loaded on the support silica. The impregnated silica displayed good thermal-stability at 250 °C. The CO2 adsorption isotherms were measured to examine CO2 adsorption on adsorbents, and the results showed that the capacity was increased significantly after modification. The CO2 isosteric adsorption heats calculated from the isotherms showed that the adsorption interaction of CO2 with the functionalized material may be mainly an intermolecular force or hydrogen bond. Fixed-bed breakthrough model of CO2 adsorption on functionalized silica was successfully developed to describe the breakthrough curves under different adsorption temperature, CO2 concentration, and gas flow rate. The mass transfer coefficients of CO2 were calculated from the breakthrough model, the results showed that adsorption rate could be promoted by increasing temperature, flow rate and CO2 concentration, among which the effect of gas flow rate is the most obvious.

Zhao, Yi; Shen, Yanmei; Bai, Lu; Ni, Shiqing

2012-11-01

73

Comparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and restricted fragment length polymorphism among fenugreek accessions.  

PubMed

Protein and DNA polymorphismswere surveyed among seven accessions of wild fenugreek (Trigonellafoenum-graecum L.) to estimate their genetic diversity and relationships. Samples were obtained from diverse ecogeographical areas in Saudi Arabia and Yemen. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of seed storage protein showed genetic variations among fenugreek germplasms, both quantitatively and qualitatively, generating a total of 168 polypeptide bands with different molecular weights ranging from 4.5 to 300 kDa. Twenty-six of these bands were polymorphic, with a considerable polymorphism value (80.00%). Furthermore, restriction fragment length polymorphism (RFLP) analysis was also employed, which was based on the ability of four restriction enzymes (EagI, EcoRI, FspI, and HindIII) to cleave genomic DNA of the plant materials at specific target nucleotide sequences into different numbers of DNA fragments. RFLP analysis revealed 166 fragments with known sequences and variable lengths ranging from 80 to 4000 bp with a highly degree of polymorphism (88.71%). Data derived from SDS-PAGE or RFLP analyses were used to produce dendrograms, which clustered the studied fenugreek accessions into different groups based on the unweighted pair group method with arithmetic mean (UPGMA). The resulting relationships indicated that these two marker techniques were nearly equivalent, but not identical, with respect to phylogenetic information. In conclusion, SDS-PAGE analysis of seed proteins should be augmented with RFLP analysis of DNA for reliable estimates of genetic diversity among fenugreek germplasms. PMID:24338424

Haliem, E A; Al-Huqail, A A

2013-01-01

74

Human liver alkaline phosphatase purified by affinity chromatography, ultracentrifugation and polyacrylamide-gel electrophoresis.  

PubMed Central

A method is presented for the preparation of human liver alkaline phosphatase (orthophosphoric monoester phosphohydrolase, EC 3.1.3.1). The method gives a purification factor of 12.5 X 10(3) over the initial aq. butan-1-ol extract, a recovery of 6.0% and a specific activity for the preparation of 1450-1550 units/mg of protein, 1 unit being defined as the amount of enzyme catalysing the hydrolysis of 1mumol of p-nitrophenyl phosphate/min at 35 degrees C in 0.1 M-2-amino-2-methylpropan-1-ol/HCl buffer, pH 10.5, containing 10mM-p-nitrophenyl phosphate. Homogeneity was studied by ultracentrifugation, by immunoelectrophoresis and by polyacrylamide-gel electrophoresis. A single contaminating protein was present which was less than 5% of the total. Ultracentrifugation and equilibrium-gradient-pore electrophoresis techniques indicated a mol.wt. of 156000 and 160000 respectively. Equilibrium-gradient-pore electrophoresis indicated that the alkaline phosphatase molecule is possibly a dimer, comprising two subunits of about 80000 mol.wt. Amino acid analysis proved remarkably similar to that for alkaline phosphatase from other sources, regardless of species. Images PLATE 1

Latner, A L; Hodson, A W

1976-01-01

75

Investigation of tetrakis hydroxymethyl phosphonium chloride as an antioxidant for use in x-ray computed tomography polyacrylamide gel dosimetry  

NASA Astrophysics Data System (ADS)

Of the antioxidants used to scavenge oxygen in polymer gel dosimeters, tetrakis (hydroxymethyl) phosphonium chloride (THPC) has been shown to hold great promise due to its rapid oxygen scavenging abilities. In this study we (a) investigate the use of THPC as an antioxidant for polyacrylamide gel (PAGAT) dosimeters used in conjunction with x-ray computed tomography (CT) and (b) work to establish the reaction mechanisms of THPC with the polymer gel constituents. We establish the dose response reproducibility of PAGAT dosimeters when imaged with CT and show that PAGAT dosimeters exhibit highly reproducible dose responses for a range of irradiation times post gel manufacture (2-6 h) and CT imaging times post gel irradiation (1-5 days). The THPC concentration within the gel leading to a maximized dose response and minimized O2 inhibition of polymerization is found to be ~4.5 mM. We further assess the stability of PAGAT dosimeters by investigating the reactions of THPC with the individual gel constituents. The importance of utilizing deionized water in polymer gel manufacture is noted. We show that, while THPC remains unreactive with acrylamide and bis-acrylamide under unirradiated conditions, THPC can react with gelatin to increase the cross-linking of the gelatin matrix in unirradiated dosimeters. THPC reactions with gelatin can lead to the lower observed dose sensitivity of PAGAT (~0.36 ± 0.04 H Gy-1) as compared to polyacrylamide gels manufactured under anoxic conditions (~0.83 ± 0.03 H Gy-1). The reactions of THPC which lead to O2 scavenging, and potential reactions of THPC with other gel constituents, are proposed.

Jirasek, A.; Hilts, M.; Shaw, C.; Baxter, P.

2006-04-01

76

Immobilization of microbial cells in crosslinked, prepolymerized, linear polyacrylamide gels: antibiotic production by immobilized Streptomyces clavuligerus cells  

SciTech Connect

A mild method for the immobilization of whole microbial cells has been developed. Cells were suspended in a solution of preformed, linear, water-soluble polyacrylamide chains, partially substituted with acylhydrazide groups. The prepolymerized backbone polymer was crosslinked, in the presence of viable cells, by stoichiometric amounts of dialdehydes such as glyoxal, glutardialdehyde, and periodate-oxidized polyvinyl alcohol. The crosslinking reaction, carried out in cold, neutral physiological conditions resulted in cells entrapped in gels with physical properties similar to those of the common polyacrylamide gels. However, cell damage generally caused by the acrylamide monomer was avoided. Resting Streptomyces clavuligerus cells, possessing a high capacity for antibiotic production, were entrapped according to this procedure. These immobilized cells produced cephalosporins continuously for 96 hours with yields similar to those of free resting cells. The same cells, when immobilized by direct polymerization of acrylamide monomers, yielded significantly lower amounts of antibiotics. (Refs. 19).

Freeman, A.; Aharonowitz, Y.

1981-12-01

77

Protein concentration of cerebrospinal fluid by precipitation with Pyrogallol Red prior to sodium dodecyl sulphate-polyacrylamide gel electrophoresis  

Microsoft Academic Search

The Pyrogallol Red Molybdate (PRM) and Coomassie Brilliant Blue (CBB) protein dye-binding assays have been applied to samples of cerebrospinal fluid (CSF) to investigate protein concentration by dye precipitation prior to sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The protein concentration values of the CSF samples (N=62) showed good agreement between the PRM and CBB assays as indicated by linear regression

Katherine M Williams; Thomas Marshall

2001-01-01

78

A new isoelectric focusing system for fast two-dimensional gel electrophoresis using a low-concentration polyacrylamide gel supported by a loose multifilament string.  

PubMed

A new isoelectric focusing (IEF) system for two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) has been proposed. In this system, a super-soft and tough IEF gel was achieved by casting polyacrylamide gel down to 2.0% T using a loose multifilament string (LMS) of nylon as a gel support. The IEF apparatus for the LMS-gel, fabricated from acrylic boards, had a cooling water chamber, and eliminated the need of electrode solutions by directly connecting the two ends of individual gels to platinum electrodes. The carrier ampholyte-generated pH gradients using the new IEF system was stable over a long duration of time and a wide range of voltages, and the IEF time became shorter using a 2.0% T gel than using a 4.0% T gel. Also, the LMS-gels prepared in different runs exhibited excellent reproducibility. The new IEF system was applied to 2-D PAGE of a chicken skeletal muscle extract, and it was found that the protein loading capacity, protein entry into the LMS-gels, and protein transfer efficiency from the first-dimensional to the second-dimensional gels were significantly improved by using a low-concentration (2.5% T) gel. Also, proteins of high molecular weight of more than 200 kDa were observed in the 2-D maps, and therefore the new IEF system has a very good potential to be applied for fast 2-D PAGE of high molecular-weight proteins. PMID:15636514

Li, Jinxiang; Ogasawara, Ayaka; Odake, Tamao; Umemura, Tomonari; Tsunoda, Kin-ichi

2004-12-01

79

Sequence analysis of 5'[32P] labeled mRNA and tRNA using polyacrylamide gel electrophoresis.  

PubMed Central

Sequence analysis of 5'-[32P] labeled tRNA and eukaryotic mRNA using an adaptation of a method recently described by Donis-Keller, Maxam and Gilbert for mapping guanines, adenines and pyrimidines from the 5'-end of an RNA is described. In addition, a technique utilizing two-dimensional polyacrylamide gel electrophoresis for identification of pyrimidines within a sequence is described. 5'-[32P] Labeled rabbit beta-globin mRNA and N. crassa mitochondrial initiator tRNA were partially digested with T1- RNase for cleavage at G residues, with U2-RNase for cleavage at A residues, with an extracellular RNase from B. cereus for cleavage at pyrimidine residues and with T2-RNase or with alkali for cleavage at all four residues. The 5'-[32P] labeled partial digestion products were separated according to their size, by electrophoresis in adjacent lanes of a polyacrylamide slab gel and the location of G's, A's and of pyrimidines extending 60-80 nucleotides from the 5'-end of the RNA determined. Two-dimensional polyacrylamide gel electrophoresis was used to separate the 5'-[32P] labeled fragments present in partial alkali digests of a 5'-[32P] labeled mRNA. The mobility shifts corresponding to the difference of a C residue were distinct from those corresponding to a U residue and this formed the basis of a method for distinguishing between the pyrimidines. Images

Lockard, R E; Alzner-Deweerd, B; Heckman, J E; MacGee, J; Tabor, M W; RajBhandary, U L

1978-01-01

80

Pseudomonas aeruginosa exotoxin: purification by preparative polyacrylamide gel electrophoresis and the development of a highly specific antitoxin serum.  

PubMed Central

Pseudomonas aeruginosa exotoxin has been purified to a specific activity of 12,000 to 16,000 mouse median lethal doses/mg of protein. Total recovery was about 25%, and the degree of purification was approximately 3,000-fold. Preparative polyacrylamide gel electrophoresis greatly facilitated purification. As judged by analytical disc gel electrophoresis, the purified toxin contained one major band of protein and only a negligible amount of contamination. Antiserum prepared against the purified toxin neutralized the lethal activity of crude toxin preprations and reacted by double immunodiffusion with a single component of concentrated broth cultures of P. aeruginosa isolates obtained from a clinical source. Images

Callahan, L T

1976-01-01

81

The application of amine-terminated silicon quantum dots on the imaging of human serum proteins after polyacrylamide gel electrophoresis (PAGE).  

PubMed

Novel amine-terminated silicon (Si) quantum dots (QDs) were synthesized and applied for the detection of human serum proteins on gels directly after polyacrylamide gel electrophoresis (PAGE). The diameter of these stable amine-terminated Si?QDs was in the range of 0.5-2.0 nm. In this study, the fluorescent imaging conditions, such as the buffer solution, pH value, buffer concentration and quantity of Si?QDs, were optimized and the possible mechanisms of Si?QDs-protein interaction were analyzed. The mode of Si?QDs and human serum albumin association was found to occur by hydrogen bond interactions; this was probably attributed to the interaction between the amino group of amine-terminated Si?QDs and the carboxyl group of proteins. Meanwhile, human serum proteins separated by native 1D and native 2D electrophoresis were detected by Si QD-based fluorescent imaging. Some proteins, such as isoform 1 of ?-1-antitrypsin, complement C3 (Fragment) and hemopexin, which were identified by mass spectrometry (MS), were easily detected by using Si?QDs, but not with CBB-R250 staining. The Si?QDs-based fluorescent imaging technique with high resolution is a sensitive and dependable method for direct detection of human serum proteins, and has enormous potential in clinical diagnosis. PMID:22249969

Liu, Pingping; Na, Na; Huang, Lingyun; He, Dacheng; Huang, Changgang; Ouyang, Jin

2012-01-27

82

Precast commercial polyacrylamide gels for separation of DNA amplificates by temperature gradient gel electrophoresis: application to clonality analysis of lymphomas.  

PubMed

The third complementary determining region (CDR-III) of the rearranged immunoglobulin heavy chain (IgH) genes represents a unique marker for a lymphocyte and its clonal descendants and can be amplified by the polymerase chain reaction (PCR) technique. This approach has markedly enhanced the sensitivity for detection of clonal lymphocyte populations in patients with malignant B-lymphoid neoplasias. To monitor minimal residual disease (MRD) in tissue specimens during or after antineoplastic treatment, the problem of detecting the presence of a few clonal (malignant) lymphocytes in coexistence with a majority of polyclonal lymphocytes has to be addressed. Semi-nested PCR amplification of CDR-III rearrangements from specimen infiltrated by tumor cells generates clonal signals in front of a polyclonal background, and therefore high resolution electrophoretic techniques for separation of DNA fragments are required. Temperature gradient gel electrophoresis (TGGE) resolving DNA homo- and heteroduplexes according to their thermal stability has been successfully applied for this purpose using special electrophoretic equipment. We describe an adjustment to this technique by using a commercially available precast 0.5 mm thick polyacrylamide gel and by changing a standard horizontal electrophoretic device into a TGGE device. By this means we screened patients with B-cell lymphoma undergoing high-dosage radiochemotherapy followed by autologous transplantation for continuous presence of clonal (tumor-specific) CDR-III rearrangements. Specimens from blood and bone marrow were collected on diagnosis as well as before and after autologous transplantation. In addition, the autograft (bone marrow or peripheral blood hematopoietic stem cells) was analyzed. Tumor cells were easily detected in the transplants and in specimens collected during follow-up examinations. The clinical value of these findings remains unclear as yet because the number of cases investigated was small and the follow-up time is still too short. However, we conclude that the technique of combining the sensitivity of PCR with the specificity of high resolution TGGE is easy to use, making it possible to handle, in a clinical routine, a great number of samples within a short time in order to monitor MRD in patients with B-cell neoplasias. PMID:8738325

Suttorp, M; von Neuhoff, N; Tiemann, M; Dreger, P; Schaub, J; Löffer, H; Parwaresch, R; Schmitz, N

1996-04-01

83

Synthesis of polyacrylamide gel beads with electrostatic functional groups for the molecular imprinting of bovine serum albumin.  

PubMed

Synthetic materials capable of recognizing proteins are important in separation, biosensors and biomaterials. In this study, bovine serum albumin-imprinted soft-wet polyacrylamide gel beads were prepared via inverse-phase suspension polymerization, using acrylamide and N,N'-methylene diacrylamide as polymeric matrix components and methacrylic acid as functional monomer. The adsorption study showed, through the imprinting process, that the imprinted gel beads had much higher adsorption capacity than the nonimprinted gel beads, and that the matching of the surface zeta-potential between the templates and the imprinted gel beads can enhance the imprinting effect. Adsorption kinetics indicated that the adsorption process could be described as an apparent first-order kinetic process for the gel beads. From the adsorption isotherm curve, we found that the adsorption of the imprinted gel beads was in agreement with the Langmuir adsorption model. Moreover, selectivity testing of the imprinted gel beads showed that imprinted gel beads exhibited good recognition for BSA as compared to the control protein. We speculate that the formation of complementary shapes and multiple-point electrostatic interactions between the imprinting cavities and the template proteins are the two factors that lead to the imprinting effect. PMID:16328246

Pang, Xingshou; Cheng, Guoxiang; Lu, Shulai; Tang, Erjun

2006-01-01

84

Simple and cost effective apparatus for silver staining of polyacrylamide gels with sequential reagents addition and real time monitoring.  

PubMed

Highly reproducible results in molecular biology depend a lot on effective staining and destaining methods. Silver staining of polyacrylamide DNA and protein gel has been adopted widely in the molecular biology laboratories for detecting a very low nanogram range of sample. An efficient staining of a polyacrylamide gel requires a number of well controlled and highly sensitive steps that often becomes tiresome when done manually or when there are a number of gels to be stained simultaneously. Since, silver staining is a multistep procedure that requires proper fixation and exchange of substance, a reliable protocol is necessary and a simple apparatus may be an added advantage to carry out the steps with ease and safety. Here, we describe a simple and cost effective device made from off-the-shelf components for some established silver staining protocols. Staining is done on a tray while six graduated bottles with a liquid delivery stopcock each, is connected to the tray through silicon tubing. The used up solution is drained off completely from the staining tray through a liquid outlet stopcock using vacuum pressure. The system is fixed with a camera connected to a computer for effective control of the staining process in each step. The apparatus provides the researchers with efficient staining and real time monitoring of gels without the need for handling toxic chemicals. PMID:24388443

Maurye, Praveen; Basu, Arpita; Gupta, Angshuman

2014-06-01

85

Deoxyribonuclease zymography adapted to the precast PhastGel electrophoresis media.  

PubMed

A set-up for casting fluorescent indicator agarose gels on ultrathin polyacrylamide microelectrophoresis gel media (Pharmacia PhastGel media) is described. The zymogram system allows a rapid and sensitive detection of deoxyribonuclease in various gel media, following isoelectric focusing, native and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. PMID:1692791

Straetkvern, K O; Raae, A J

1990-04-01

86

A rapid method for separation and detection of human salivary amylase isoenzymes by isoelectric focusing in polyacrylamide gel.  

PubMed

Human salivary proteins were separated by isoelectric focusing on polyacrylamide gel in flat beds at 1000 V for 40 min. Amylase activity was detected after immersing the gel in 0.4 M tris-HCI buffer pH 7.4 to equilibrate the pH gradient. The enzyme activity was detected after diffusion into an overlayer of agarose gel containing an insoluble dye-starch polymer (Phadebas). Both whole human saliva and parotid saliva from 15 different persons contained four amylase components, except in three cases where only three bands were detected. The bands were all focused within a rather narrow pH range (pH 5.4-7.2) and the results were very reproducible. PMID:1065950

Wadström, T; Nord, C E; Kjellgren, M

1976-07-01

87

Improvement deoxyribo nucleic acid spots classification in polyacrylamide [correction of polyacrilamide] gel images using photometric normalization algorithms.  

PubMed

A comparative study of four enhancement algorithms traditionally used in computer vision for photometric normalization of images affected by illumination changes is presented in this paper. We experimented with the performance of these approaches to reduce the low frequency multiplicative noise that is produced as a result of a non-homogeneity illumination or a non-homogeneity developed chemical process in polyacrylamide gel electrophoresis images for the purpose of automatic classification of deoxyribo nucleic acid (DNA). The algorithms are tested on a database and their results are compared in a system for feature extraction and DNA classification. PMID:17605994

Garea Llano, Eduardo; Silva Mata, Francisco; Talavera Bustamante, Isneri; Hernández González, Noslen; González Gazapo, Ricardo

2007-07-01

88

Mutation analysis of fragile X syndrome by Southern blot, radioactive PCR, silver-stained polyacrylamide gel and DIG DNA  

SciTech Connect

Fragile X syndrome is the most common inherited form of mental retardation. In fragile X syndrome, the underlying mutation is caused by an expansion of the CTG triplet in the 5{prime} untranslated region of the FMR-1 gene located at Xq27.3 and diagnosed by methylation of the associated CpG island. This disorder becomes clinically manifested when the mutation is caused by an expansion of (CGG)n reaching a threshold of about 600bp (200 repeats). The number of inserted repeats increases through the generation. We have analyzed fragile X syndrome by 4 different methods: Southern blot, radioactive PCR, polyacrylamide gel and DIG DNA labeling/detection techniques. Southern blot and DIG DNA labeling/detection by double DNA digestion with EcoRI and EagI reveals both the presence of the mutation and the methylation status. Radioactive PCR and silver-stained polyacrylamide gel is a rapid and sensitive technique to define the unaffected carriers and NTMs, but it is difficult to amplify such a highly GC-rich sequence. Further testing in other fragile X patients is currently in progress.

Lee, Sook-Hwan; Kim, Un-Kyung; Chung-Woong, M.S. [CHA General Hospital, Seoul (Korea, Republic of)] [and others

1994-09-01

89

Activity staining of cellulases in polyacrylamide gels containing mixed linkage beta-glucans.  

PubMed

Endoglucanase and cellobiohydrolase components of thermophilic cellulases can be detected in situ after gel electrophoresis in the presence of sodium dodecyl sulfate by incorporating a mixed linkage beta-glucan (barley beta-glucan, lichenan) in the separation gel. Zymograms are prepared after a renaturation treatment and incubation by staining the gel with Congo red. This method is suitable for the detection of beta-glucanases with different substrate specificities cleaving beta-1,4-, beta-1,4-1,3-, or beta-1,3-glucans. Cellobiohydrolase activities can be detected by adding 4-methylumbelliferyl-beta-D-cellobioside to the incubation buffer. The gels are subsequently stained with Coomassie blue to establish identical molecular weights of beta-glucanase and protein bands. Applications of this technique for the comparison of cellulases and for the identification of cellulase components expressed from recombinant clones are presented. PMID:2445222

Schwarz, W H; Bronnenmeier, K; Gräbnitz, F; Staudenbauer, W L

1987-07-01

90

An optimized procedure for sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of hydrophobic peptides from an integral membrane protein.  

PubMed

A procedure for successful analysis of the hydrophobic tryptic peptides of the Neurospora crassa plasma membrane H+-ATPase by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) is described. The features of this procedure that are essential for the best results include (i) treatment of the hydrophobic peptide samples with neat trifluoroacetic acid, (ii) dissolution and disaggregation of the hydrophobic peptide samples with SDS at 0 degrees C, (iii) SDS-PAGE of the hydrophobic peptide samples in gels containing a 200:1 ratio of acrylamide to bisacrylamide and a 5-20% convex acrylamide gradient, and (iv) silver-staining of the gels after electrophoresis. This method results in the reproducible resolution and visualization of the H+-ATPase hydrophobic tryptic peptides, which range in size from ca. 5 to 21 kDa, as well as other peptides and proteins ranging in size from ca. 2.5 to 150 kDa. The methods described should also prove useful in other studies where resolution and visualization of hydrophobic peptides of integral membrane proteins are required. PMID:2525882

Hennessey, J P; Scarborough, G A

1989-02-01

91

Single nucleotide polymorphisms analysis of noise-induced hearing loss using three-dimensional polyacrylamide gel-based microarray method.  

PubMed

Noise induced hearing loss (NIHL) is a complex occupational hazard caused by an interaction between genetic and environmental factors. Millions of Chinese industrial people are daily exposed to high level of noise. Although the environmental risk factors have been studied extensively, the nature of the genetic factors contributing to HIHL has not yet been clarified. In this study, we investigated 15 single nucleotide polymorphisms (SNPs) in 6 candidate genes influence susceptibility to noise in Chinese noise-exposed workers. Data from 3-dimensional polyacrylamide gel-based microarray platforms were analyzed. 103 blood samples were collected from noise-exposed laborers in Ningbo, Zhejiang, China. Subsequently, the interaction between noise exposure and genotypes and their effect on NIHL were analysed using logistic regression. Two interesting results were observed between noise exposure levels and genotypes of three SNPs, hence confirming that they are NIHL susceptibility genes in Chinese population. PMID:22416580

Xia, Guihua; Gao, Weiwei; Ji, Ke; Liu, Shaosheng; Wan, Bo; Luo, Junfeng; Bai, Yunfei

2011-12-01

92

Protein concentration of cerebrospinal fluid by precipitation with Pyrogallol Red prior to sodium dodecyl sulphate-polyacrylamide gel electrophoresis.  

PubMed

The Pyrogallol Red Molybdate (PRM) and Coomassie Brilliant Blue (CBB) protein dye-binding assays have been applied to samples of cerebrospinal fluid (CSF) to investigate protein concentration by dye precipitation prior to sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The protein concentration values of the CSF samples (N=62) showed good agreement between the PRM and CBB assays as indicated by linear regression analysis (y(PRM)=1.033x(CBB)+1.004 in units of mg/l, r=0.99) but the PRM assay was optimal for protein concentration as the PRM protein-dye complex was less soluble allowing protein recovery over a wider working range. Dye precipitation using PRM is recommended as a simple, rapid and economic method for protein concentration of samples of CSF prior to SDS-PAGE. PMID:11245891

Williams, K M; Marshall, T

2001-02-26

93

Human cytomegalovirus-induced immediate early antigens: analysis in sodium dodecyl sulfate-polyacrylamide gel electrophoresis after immunoprecipitation.  

PubMed Central

Immediate early antigen (IEA) induced in human lung fibroblasts by human cytomegalovirus was characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis after immunoprecipitation with IEA-positive human sera. Two polypeptides of 76,000 daltons (76K) and 82K were detectable within 90 min after infection. Polypeptides of similar molecular weight were also found in immunoprecipitates of human cytomegalovirus-infected cells nonpermissive for virus replication. IEA is located within the nucleus, although some of the 76K material appears to be located on the outer nuclear membrane. Raising salt concentrations in the extraction buffer increased antigen extraction. The contribution of these IEA polypeptides to IEA nuclear fluorescent staining is discussed. Images

Michelson, S; Horodniceanu, F; Kress, M; Tardy-Panit, M

1979-01-01

94

Antigens of scrub typhus rickettsiae: separation by polyacrylamide gel electrophoresis and identification by enzyme-linked immunosorbent assay.  

PubMed Central

Antigens of plaque-purified Rickettsia tsutsugamushi strains Gilliam, Karp, and Kato were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and were analyzed by an enzyme-linked immunosorbent assay. Six antigens were identified in each of the three prototype strains; in strain Gilliam, these antigens were located in the cell envelope fraction of the organisms. Reactivity of these isolated antigens with homologous or heterologous immune sera indicated that different macromolecules existed in all three strains, although they exhibited very similar mobilities during electrophoresis. Antigens of strain Gilliam reacted equally well with antibodies directed against Gilliam, Karp, or Kato rickettsiae. However, strains Karp and Kato each had two distinct antigens which did not react with heterologous antisera. R. tsutsugamushi antigens retained immunogenicity after electrophoresis, and antisera raised against them reacted with intact organisms and exhibited specificity in reactions with isolated antigens.

Eisemann, C S; Osterman, J V

1981-01-01

95

Background-free, fast protein staining in sodium dodecyl sulfate polyacrylamide gel using counterion dyes, zincon and ethyl violet.  

PubMed

A background-free, fast protein staining method in polyacrylamide gel electrophoresis using an acidic dye, zincon (ZC) and a basic dye, ethyl violet (EV) is described. It is based on the counterion dye staining technique that employs two oppositely charged dyes to form an ion-pair complex in staining solution. The selective binding of free dye molecules to proteins in acidic solution produces bluish violet-colored bands. It is a rapid and end-point staining procedure, involving only fixing and staining steps that are completed in 1-1.5 h. The detection limit of this method is 8-15 ng of protein that is comparable to the sensitivity of the colloidal Coomassie Brilliant Blue G (CBBG) stain. Due to its sensitivity and speed, this stain may be more practical than any other dye-based stains for routine laboratory purposes. PMID:12481259

Choi, Jung-Kap; Tak, Keong-Hoon; Jin, Li-Tai; Hwang, Sun-Young; Kwon, Tae-Ik; Yoo, Gyurng-Soo

2002-12-01

96

Comparison of the influence of inorganic salts on the NMR dose sensitivity of polyacrylamide-based gel dosimeter  

NASA Astrophysics Data System (ADS)

On the NMR dose sensitivities of polyacrylamide-based gel dosimeters irradiated by X-ray, the additive effect of various inorganic salts (electrolytes) is investigated. Among the various combination of cations (Li+, Na+, K+, Mg2+, Ca2+, Sr2+, Ba2+, Zn2+ and Al3+) and anions (Cl-, NO-3 and SO2-4), MgCl2 is shown to be the most effective sensitizer. In the result, it is suggested that the extent of the increase of the dose sensitivity may correlate to the hydration power of cations rather than anions. Contrary to the dose sensitivity enhancement, the depression of melting point caused by the additives is also pointed out.

Hayashi, S.-I.; Kawamura, H.; Usui, S.; Tominaga, T.

2013-06-01

97

Routine diagnosis with PhastSystem compared to conventional electrophoresis: automated sodium dodecyl sulfate-polyacrylamide gel electrophoresis, silver staining and western blotting of urinary proteins.  

PubMed

The recent introduction of the PhastSystem, an automatic electrophoresis and staining system with precast gradient-gels, allows rapid and reproducible analysis of proteinuria in patients suffering from renal injury. A routine method for sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis (SDS-PAGE) and silver staining of unconcentrated urine specimens in the PhastSystem is described and compared to our conventional "macro"-method with self-cast SDS-polyacrylamide gradient gels. The method described for the PhastSystem using 0.3 microL sample volumes and an 8-25% polyacrylamide gradient gel leads to highly reproducible results within 1.5 h. Before electrophoresis urine specimens were neither concentrated nor dialyzed. Samples with a protein concentration exceeding 5 mg/mL had to be diluted 1:5 (v/v). Analysis and documentation of PhastGels appeared as easy as with our conventional SDS-PAGE. Protein bands could reliably be identified by Western blotting. Urine and serum proteins, separated in PhastGels, were electrophoretically transferred to nitrocellulose and detected with specific antibodies against human albumin, transferrin, alpha-1-antitrypsin and IgG. Comparison of several standard kits for molecular weight determination revealed considerable differences concerning the quality of protein separation patterns. Availability of precast gels and automatization of SDS-PAGE and staining allows easy standardization of urine SDS-PAGE among clinical routine laboratories. PMID:2469571

Scherberich, J E; Fischer, P; Bigalke, A; Stangl, P; Wolf, G B; Haimerl, M; Schoeppe, W

1989-01-01

98

Fluorography--limitations on its use for the quantitative detection of /sup 3/H- and /sup 14/-C-labeled proteins in polyacrylamide gels  

SciTech Connect

The suitability of fluorography for the detection of /sup 3/H- and /sup 14/C-labeled proteins on polyacrylamide gradient gels has been investigated. If was found that the absorbance of the fluorographic film image produced by a given level of radioactivity decreased as the acrylamide concentration in the gel increased. The use of Coomassie brilliant blue protein dyes to stain the gel prior to fluorography reduced the absorbance of the fluorographic image. It is concluded that quantitative fluorography can only be applied to unstained gels of a uniform acrylamide concentration.

Harding, C.R.; Scott, I.R.

1983-03-01

99

Quantification of AAV Particle Titers by Infrared Fluorescence Scanning of Coomassie-Stained Sodium Dodecyl Sulfate-Polyacrylamide Gels  

PubMed Central

Abstract Adeno-associated virus (AAV)-based vectors have gained increasing attention as gene delivery vehicles in basic and preclinical studies as well as in human gene therapy trials. Especially for the latter two—for both safety and therapeutic efficacy reasons—a detailed characterization of all relevant parameters of the vector preparation is essential. Two important parameters that are routinely used to analyze recombinant AAV vectors are (1) the titer of viral particles containing a (recombinant) viral genome and (2) the purity of the vector preparation, most commonly assessed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) followed by silver staining. An important, third parameter, the titer of total viral particles, that is, the combined titer of both genome-containing and empty viral capsids, is rarely determined. Here, we describe a simple and inexpensive method that allows the simultaneous assessment of both vector purity and the determination of the total viral particle titer. This method, which was validated by comparison with established methods to determine viral particle titers, is based on the fact that Coomassie Brilliant Blue, when bound to proteins, fluoresces in the infrared spectrum. Viral samples are separated by SDS–PAGE followed by Coomassie Brilliant Blue staining and gel analysis with an infrared laser-scanning device. In combination with a protein standard, our method allows the rapid and accurate determination of viral particle titers simultaneously with the assessment of vector purity.

Kohlbrenner, Erik; Henckaerts, Els; Rapti, Kleopatra; Gordon, Ronald E.; Linden, R. Michael; Hajjar, Roger J.

2012-01-01

100

SDS-polyacrylamide gel electrophoresis of buffalo bulls seminal plasma proteins and their relation with semen freezability.  

PubMed

The objective of this study was to evaluate the protein profiles of seminal plasma in buffalo bulls and to examine their correlation with semen characteristics. Semen of 10 buffalo bulls were collected by a bovine artificial vagina. Semen characteristics (motility, morphology, viability and concentration) were recorded. A part of the semen sample (1 ml) was diluted by tris-egg yolk-glycerol extender, packed in French straws and was frozen in liquid nitrogen. The straws were later thawed and semen characteristics were compared with those of the fresh semen. Seminal plasma was harvested by centrifugation; treated with cold ethanol and then, underwent SDS-polyacrylamide gel electrophoresis (PAGE). Twenty five protein bands were identified on the gel, of which those of <35.5 kDa were prominent (72% of the bands). Of these protein fractions, 24.5 kDa was significantly correlated with sperm progressive motility in fresh and viability in frozen-thawed semen while 45 kDa bands were correlated with abnormal morphology in frozen-thawed semen; 55 kDa protein fractions were correlated with sperm viability of fresh semen. Progressive motility, viability and abnormal sperm morphology of frozen-thawed semen were highly correlated with these parameters in the fresh semen. In conclusion, seminal plasma protein fractions in buffalo bulls are similar to those reported in other animal species and have some correlations with semen characteristics before and after freezing. PMID:17433580

Asadpour, R; Alavi-Shoushtari, S M; Rezaii, S Asri; Ansari, M H Kh

2007-12-01

101

Use of Two-Dimensional Polyacrylamide Gel Electrophoresis to Identify and Classify Rhizobium Strains  

PubMed Central

Fifty-seven strains of various Rhizobium species were analyzed by two-dimensional gel electrophoresis. Since the protein pattern on such gels is a reflection of the genetic background of the tested strains, similarities in pattern allowed us to estimate the relatedness between these strains. All group II rhizobia (slow growing) were closely related and were very distinct from group I rhizobia (fast growing). Rhizobium meliloti strains formed a distinct group. The collection of R. leguminosarum and R. trifolii strains together formed another distinct group. Although there were some similarities within the R. phaseoli, sesbania rhizobia, and lotus rhizobia, the members within these seemed much more diverse than the members of the above groups. The technique also is useful to determine whether two unknown strains are identical. Images

Roberts, Gary P.; Leps, Walter T.; Silver, Lin E.; Brill, Winston J.

1980-01-01

102

Residual Casein Fractions in Ripened Cheese Determined by Polyacrylamide-Gel Electrophoresis  

Microsoft Academic Search

Polyaerylamide-gel electrophoresis (PAE) of ripened-cheese caseins provides an ideal means of studying cheese-ripening by detecting small changes in the specific casein fractions. Properties, such as molecu- lar sieving, and the facility to use simulta- neously casein standards, apparently are important advantages of PAE. Rennet enzymes appear specifically to alter a~-casein after curd formation in Cheddar cheese manufacture, fl-Casein ev- idently

R. A. Ledford; A. C. O'Sullivan; K. R. Nath

1966-01-01

103

Exogenous expression of human SGLT1 exhibits aggregations in sodium dodecyl sulfate polyacrylamide gel electrophoresis  

PubMed Central

Sodium/glucose co-transporter 1 (SGLT1), which actively and energy-dependently uptakes glucose, plays critical roles in the development of various diseases including diabetes mellitus and cancer, and has been viewed as a promising therapeutic target for these diseases. Protein-protein interaction with EGFR has been shown to regulate the expression and activity of SGLT1. Exogenous expression of SGLT1 is one of the essential approaches to characterize its functions; however, exogenously expressed SGLT1 is not firmly detectable by Western blot at its calculated molecular weight, which creates a hurdle for further understanding the molecular events by which SGLT1 is regulated. In this study, we demonstrated that exogenous SGLT1 functions in glucose-uptake normally but is consistently detected near the interface between stacking gel and running gel rather than at the calculated molecular weight in Western blot analysis, suggesting that the overexpressed SGLT1 forms SDS-resistant aggregates, which cannot be denatured and effectively separated on SDS-PAGE. Co-expression of EGFR enhances both the glucose-uptake activity and protein level of the SGLT1. However, fusion with Flag or HA tag at its carboxy- but not its amino-terminus abolished the glucose-uptake activity of exogenous SGLT1 without affecting its protein level. Furthermore, the solubility of SGLT1 aggregates was not affected by other detergents but was partially improved by inhibition of o-link glycosylation. These findings suggested exogenous overexpression of SGLT1 can function normally but may not be consistently detectable at its formula weight due to its gel-shift behavior by forming the SDS-resistant aggregates.

Huang, Wei-Chien; Hsu, Sheng-Chie; Huang, Shyh-Jer; Chen, Yun-Ju; Hsiao, Yu-Chun; Zhang, Weihua; Fidler, Isaiah J; Hung, Mien-Chie

2013-01-01

104

OFFGEL isoelectric focusing and polyacrylamide gel electrophoresis separation of platinum-binding proteins.  

PubMed

In this work a 2D electrophoretic separation procedure able to maintain the integrity of platinum-protein bonds has been developed. The method is based on the use of sequential OFFGEL isoelectric focussing (IEF) and PAGE. A systematic study of the reagents used for PAGE, for OFFGEL-IEF separation, and post-separation treatment of gels (such as enzymatic digestion and sample preparation for MS analysis) was tackled regarding their suitability for the identification of platinum binding proteins using standard proteins incubated with cisplatin. The distribution of platinum in high and low molecular weight fractions (separated by cut-off filters) was determined by ICP-MS, which allows evaluating platinum-protein bond stability under the conditions studied. SDS-PAGE in the absence of ?-mercaptoethanol or dithiotreitol preserved the platinum-protein bonds. In addition, neither the influence of the electric field during the electrophoretic separation, nor the processes of fixing, staining and destaining of proteins in the gel did result in the loss of platinum from platinum binding proteins. SDS-PAGE under non-reducing conditions provides separation of platinum-binding proteins in very narrow bands with quantitative recoveries. Different amounts of platinum-bound proteins covering the range 0.3-2.0 ?g were separated and mineralised for platinum determination, showing good platinum linearity. Limits of detection for a mixture of five standard proteins incubated with cisplatin were between the range of 2.4 and 13.9 pg of platinum, which were satisfactory for their application to biological samples. Regarding OFFGEL-IEF, a denaturing solution without thiourea and without dithiotreitol is recommended. The suitability of the OFFGEL-IEF for the separation of platinum binding proteins of a kidney cytosol was demonstrated. PMID:21255782

Mena, Ma Luz; Moreno-Gordaliza, Estefanía; Moraleja, Irene; Cañas, Benito; Gómez-Gómez, Ma Milagros

2011-03-01

105

Detection of trypsin- and chymotrypsin-like proteases using p-nitroanilide substrates after sodium dodecyl sulphate polyacrylamide gel electrophoresis.  

PubMed

Specific chromogenic p-nitroanilide substrates have proved useful for localizing proteolytic enzymes, such as trypsin, chymotrypsin and elastase after separation by agarose gel electrophoresis and when immobilized on nitrocellulose. This procedure was further developed for use with sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). After SDS-PAGE, proteins were transferred electrophoretically to a nitrocellulose membrane. The membrane was incubated for 10-60 min with Bz-Ile-Glu-Gly-Arg-p-nitroanilide as a substrate for detection of trypsin-like proteases and with MeO-Suc-Arg-Pro-Tyr-p-nitroanilide for detection of chymotrypsin. The yellow p-nitroanilide released at the site of proteolytic activity was converted into a visible and stable red azo dye. By this method was identified and determined the molecular weight of a trypsin-like protease that occurs at high concentrations in mucinous ovarian tumour cyst fluid together with its specific inhibitor peptide, tumour-associated trypsin inhibitor (TATI). The method was also used to visualize trypsin and chymotrypsin in human pancreatic juice. Using the trypsin substrate, three proteolytic bands, corresponding to Mr of 22,000, 24,000 and 26,000 daltons, were visualized in pancreatic juice, while the proteolytic zones in cyst fluid had Mr of 25,000 and 28,000 daltons. With the chymotrypsin substrate, a band of 29,000 daltons was visualized in pancreatic juice, whereas no activity was detected in cyst fluid. By incubation of the blotted cyst fluid proteins with 125I-labelled TATI, a pattern of bands at 25,000 and 28,000 daltons was detected identical to that obtained with the chromogenic substrate. PMID:2768384

Koivunen, E

1989-05-26

106

Studies on lectins. XXXVI. Properties of some lectins prepared by affinity chromatography on O-glycosyl polyacrylamide gels.  

PubMed

A number of lectins has been purified by affinity chromatography on O-glycosyl polyacrylamide gels. The lectins isolated (and the particular sugar ligands used in the affinity carriers) are as follows: Anguilla anguilla, serum (alpha-L-fucosyl-), Vicia cracca, seeds; Phaseolus lunatus, seeds; Glycine soja, seeds; Dolichos biflorus, seeds; Maclura pomifera, seeds; Sarothamnus scoparius, seeds; Helix pomatia, ablumin glands; Clitocybe nebularis, fruiting bodies (all N-acetyl-alpha-D-galactosaminyl-); Ricinus communis, seeds (beta-lactosyl-); Ononis spinosa, root; Fomes fomentarius, fruiting bodies; Marasmius oreades, fruiting bodies (all alpha-D-galactosyl-), Canavalia ensiformis, seeds, (i.e., concanavalin A) (alpha-D-glucosyl-). Physicochemical properties of Glycine soja, Dolichos biflorus, Phaseolus lunatus, Helix Pomatia and Ricinus communis lectins corresponded well to properties of the preparations studied earlier by other workers. For the other purified lectins the essential physiochemical data (sedimentation coefficient, molecular weight, subunit composition, electrophoretic patterns, amino acid composition, carbohydrate content, isoelectric point) were established and their precipitating, hemagglutinating and mitogenic activities determined. PMID:563738

Horejsí, V; Kocourek, J

1978-01-18

107

Effects of storage time and temperature on the infectivity and effectiveness of Frankia entrapped in polyacrylamide gel.  

PubMed

Four Frankia-Casuarina endosymbiont strains were tested for their infectivity and effectiveness on C. equisetifolia plants after 1 d, 3 and 6 months of Frankia storage at 7, 28 and 40 degrees C as liquid-cultures and polyacrylamide gel (PAG)-immobilized inocula. At lower temperature the number of nodules was the same or higher than control for liquid inocula except after 6 months of storage. For the PAG-entrapped Frankia lower numbers of nodules were recorded due to the use of high Frankia titers. In general, the results showed comparable plant dry mass, total nitrogen, root to shoot and nodules to plant ratios at lower temperature treatments. Increasing time and temperature was accompanied with reduced infectivity and effectiveness on inoculated plants. No nodulation was scored on plants inoculated with liquid and PAG-entrapped inocula stored at 40 degrees C for 6 months; subsequently, plant growth was inhibited. The variations in results obtained for different strains and treatments lead to variations in plant nitrogen-fixing ability. The use of PAG as a carrier for different Frankia strains is suggested; the recommended storage temperature for PAG-immobilized Frankia in 7-28 degrees C for up to 3 months. PMID:12503402

Sayed, W F; Wheeler, C T; el-Sharouny, H M; Mohawad, S M; Abdel-Karim, M M

2002-01-01

108

Analysis of cell wall extracts of Candida albicans by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot techniques.  

PubMed Central

Cell walls of intact yeast- and mycelial-phase Candida albicans B311 were extracted with different compounds: dithiothreitol, dithiothreitol with protease, dithiothreitol with lyticase, and dithiothreitol with protease followed by beta-glucuronidase with chitinase. Extracts were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot techniques. Dithiothreitol extracts contained the most satisfactory array of components for study. Analysis of these extracts demonstrated that the outer cell wall layers of Candida blastoconidia and germ tubes contained a complex array of polysaccharides, glycoproteins, and proteins. The proteins contributed to a latticework stabilized by covalent bonds that was important in determining the porosity of the outer cell wall layers. When equivalent weights were analyzed, mycelial-phase extract contained a more varied array of proteins than did yeast-phase extract. Only a portion of proteins in mycelial-phase extract elicited antibody responses in hyperimmunized rabbits or infected humans. A polysaccharide-rich, high-molecular-weight component (migrating at a position that would correspond to proteins having molecular weights of 235,000 to 250,000) and a protein component (molecular weight, 19,000) were readily demonstrable in the mycelial-phase extract but could not be identified in the yeast-phase extract. Images

Ponton, J; Jones, J M

1986-01-01

109

In-gel staining of proteins in native poly acryl amide gel electrophoresis using tetrakis(4-sulfonato phenyl)porphyrin.  

PubMed

Protein identification in polyacrylamide gel electrophoresis (PAGE) requires post-electrophoretic steps like fixing, staining and destaining of the gel, which are time-consuming and cumbersome. We have developed a method for direct visualization of protein bands in PAGE using tetrakis(4-sulfonato phenyl)porphyrin (TPPS) as a dye without the need for any post electrophoretic steps, where separation and recovery of enzymes become much easier for further analysis. Activity staining was done to prove that the biochemical activity of the enzymes was preserved after electrophoresis. PMID:21233569

Divakar, Kalivarathan; Sujatha, Vijayan; Barath, Sridhar; Srinath, Krishnamurthy; Gautam, Pennathur

2011-01-01

110

Novel complex gel beads composed of hydrolyzed polyacrylamide and chitosan: an effective adsorbent for the removal of heavy metal from aqueous solution.  

PubMed

A novel kind of complex gel beads containing HPAM (hydrolyzed polyacrylamide) and chitosan components (HPAM-chitosan gel beads) was prepared and applied in the removal of Cu(2+), Pb(2+), and Hg(2+) ions from aqueous solutions. These gel beads exhibited a good performance for heavy metal removal. Moreover, the average diameter of these gel beads was about 1mm, which could be appropriate for use in column system. The removal order was Pb(2+)>Cu(2+)>Hg(2+) under the same conditions. The effects of different experimental parameters, such as adsorbent dosage, initial pH, temperature, and initial metal concentration, on the adsorption capacities were studied. The Freundlich model gave a better fit to the experimental data than the Langmuir model in adsorption isotherm study. Desorption study indicated that the gel beads were easy to be regenerated. PMID:19939679

Cao, Jie; Tan, Yebang; Che, Yuju; Xin, Haipeng

2010-04-01

111

Efficient analysis of egg yolk proteins and their thermal sensitivity using sodium dodecyl sulfate polyacrylamide gel electrophoresis under reducing and nonreducing conditions.  

PubMed

The multiple functional properties of egg yolk are mostly influenced by its complex protein composition. The high lipid content of egg yolk as well as the low solubility of delipidated egg yolk lipoproteins make analysis by conventional chromatographic or electrophoretic techniques a difficult task. This work describes a method to profile egg yolk proteins after delipidation with acetone using sodium dodecyl sulfate polyacrylamide gel electrophoresis on precast 8-18% T polyacrylamide gradient gels. Twenty bands were obtained for the whole egg yolk profile with molecular weights ranging between 5 and 221 kDa. The bands were identified based on their molecular weight and by comparison with isolated egg yolk subfractions. The dissociation behavior under reducing and nonreducing conditions provided additionally helpful information for identification and characterization of the yolk proteins. The method presented is very well suited for assaying the thermal sensitivity of whole yolk and its components and thus for the characterization of heat treatment processes. PMID:16302743

Guilmineau, Fabien; Krause, Ingolf; Kulozik, Ulrich

2005-11-30

112

Dried polyacrylamide gel absorption: a method for efficient elimination of the interferences from SDS-solubilized protein samples in mass spectrometry-based proteome analysis.  

PubMed

Sample preparation holds an important place in MS-based proteome analysis. For effective proteolysis and MS analysis, it is essential to eliminate the interferences while extracting the analytes of interest from complex mixtures. To address this, herein we describe a new dried polyacrylamide gel absorption method. In this method, the protein sample prepared using high concentration of SDS was directly and completely absorbed by vacuum-dried polyacrylamide gel, and then the interfering substances including SDS and some other salts were efficiently removed by in-gel washing steps while retaining the denatured proteins in the gel, thus offering a clean environment amenable to downstream buffer exchange, proteolytic digestion and digest recovery, etc. In combination with in-gel digestion and LC-MS/MS, the newly developed method was applied to the proteome analyses of membrane-enriched fraction and whole tissue homogenate. It was demonstrated that the method is suitable for the analysis of a complex biological sample and can be widely used for sample cleanup in shotgun proteome analyses. PMID:21064138

Zhou, Jian; Li, Jianglin; Li, Jianjun; Chen, Ping; Wang, Xianchun; Liang, Songping

2010-12-01

113

Macroporous polyacrylamide monolithic gels with immobilized metal affinity ligands: the effect of porous structure and ligand coupling chemistry on protein binding.  

PubMed

Macroporous polyacrylamide gels (MPAAG) with iminodiacetic acid (IDA) functionality were prepared by (i) chemical modification of polyacrylamide gel, (ii) co-polymerization of acrylamide with allyl glycidyl ether (AGE) and N,N'metylene-bis(acrylamide) (MBAAm) followed by coupling IDA ligand or (iii) by copolymerization of acrylamide and MBAAm with functional monomer carrying IDA-functionality (1-(N,N-bis(carboxymethyl)amino-3-allylglycerol). Screening for optimized conditions for the production of the MPAAG with required porous properties was performed in a 96-well chromatographic format that allowed parallel production and analysis of the MPAAG prepared from reaction mixtures with different compositions. Scanning electron microscopy of the fabricated MPAAG revealed two different types of the porous structures: monomodal macroporous structure with large interconnected pores separated by dense non-porous pore walls in case of plain gels or gels produced via copolymerization with AGE. The other type of the MPAAG (gel produced via co-polymerization with functional monomer carrying IDA-functionality) had bimodal pore structure with large interconnected pores separated by the pore walls pierced through with micropores. The effect of different modifications of MPAAG monoliths and of porous structure of the MPAAG (monomodal and bimodal porous structure) on protein binding has been evaluated. PMID:16703570

Plieva, Fatima; Bober, Beata; Dainiak, Maria; Galaev, Igor Yu; Mattiasson, Bo

2006-01-01

114

Use of polyacrylamide gel moving boundary electrophoresis to enable low-power protein analysis in a compact microdevice.  

PubMed

In designing a protein electrophoresis platform composed of a single-inlet, single-outlet microchannel powered solely by voltage control (no pumps, values, injectors), we adapted the original protein electrophoresis format-moving boundary electrophoresis (MBE)-to a high-performance, compact microfluidic format. Key to the microfluidic adaptation is minimization of injection dispersion during sample injection. To reduce injection dispersion, we utilize a photopatterned free-solution-polyacrylamide gel (PAG) stacking interface at the head of the MBE microchannel. The nanoporous PAG molecular sieve physically induces a mobility shift that acts to enrich and sharpen protein fronts as proteins enter the microchannel. Various PAG configurations are characterized, with injection dispersion reduced by up to 85%. When employed for analysis of a model protein sample, microfluidic PAG MBE baseline-resolved species in 5 s and in a separation distance of less than 1 mm. PAG MBE thus demonstrates electrophoretic assays with minimal interfacing and sample handling, while maintaining separation performance. Owing to the short separation lengths needed in PAG MBE, we reduced the separation channel length to demonstrate an electrophoretic immunoassay powered with an off-the-shelf 9 V battery. The electrophoretic immunoassay consumed less than 3 ?W of power and was completed in 30 s. To our knowledge, this is the lowest voltage and lowest power electrophoretic protein separation reported. Looking forward, we see the low-power PAG MBE as a basis for highly multiplexed protein separations (mobility shift screening assays) as well as for portable low-power diagnostic assays. PMID:22971048

Duncombe, Todd A; Herr, Amy E

2012-10-16

115

A highly sensitive "turn-on" fluorescent sensor for the detection of human serum proteins based on the size exclusion of the polyacrylamide gel.  

PubMed

A highly sensitive "turn-on" fluorescent sensor based on the size exclusion of the polyacrylamide gel was developed for the on-gels detection of human serum proteins after PAGE. The possible mechanism of this fluorescence sensor was illustrated and validated by utilizing five kinds of colloidal silver nanoparticles with different particle size distribution and six kinds of polyacrylamide gels with different pore size. It was attributed to that silver nanoparticles (<5 nm in diameter) had been selectively absorbed into the gel and formed the small silver nanoclusters, resulting in the red fluorescence. Using this new technique for the detection of human serum proteins after PAGE, a satisfactory sensitivity was achieved and some relatively low-abundance proteins (e.g. zinc-alpha-2-glycoprotein), which are the significant proteinic markers of certain diseases can be easily detected, but not with traditional methods. Furthermore, it was also successfully applied to distinguish between serums from hepatoma patient and healthy people. As a new protein detection technique, the colloidal silver nanoparticles based "turn-on" fluorescent sensor offers a rapid, economic, low background, and sensitive way for direct detection of human serum proteins, showing available potential and significance in the development of nanobiotechnology and proteome research. PMID:24150987

Xu, Shenghao; Liu, Pingping; Lu, Xin; Zhang, Jing; Huang, Lingyun; Hua, Wenhao; He, Dacheng; Ouyang, Jin

2014-02-01

116

Simultaneous concentration enrichment and electrophoretic separation of weak acids on a microchip, using in situ photopolymerized carboxylate-type polyacrylamide gels as the permselective preconcentrator.  

PubMed

A method for the simultaneous concentration and separation of weak acids using an acidic polyacrylamide gel, fabricated in the microfluidic channel of a commercial poly(methyl methacrylate)-made microchip, is reported. This approach is based on simple photochemical copolymerization for the fabrication of a permselective preconcentrator. The intersection of the poly(methyl methacrylate)-made microchip was filled with a gel solution comprising acrylamide, N,N'-methylene-bis-acrylamide, and 2-acrylamidoglycolic acid, with riboflavin as a photocatalytic initiator. In situ polymerization, near the cross of the sample outlet channel, was performed by irradiation with an argon ion laser beam that is also used as the light source for fluorimetric detection. The electrokinetic properties, combined with electrostatic repulsion between sample components and the anionic groups on the polyacrylamide gel, enable the entrapment and concentration of weak acids at the interface of the cathodic side of the gel plug. This method displays concentration factors of up to 10(5) within 3 min. The effectiveness of the ionic preconcentrator was demonstrated by the sensitive analysis of fluorescein isothiocyanate-labeled amino acids. PMID:21796791

Yamamoto, Sachio; Watanabe, Yuki; Nishida, Noriaki; Suzuki, Shigeo

2011-10-01

117

Detection of possible DNA repair enzymes on sodium dodecyl sulfate-polyacrylamide gels by protein blotting to damaged DNA-fixed membranes  

SciTech Connect

A novel method for detecting possible DNA repair enzymes on sodium dodecyl sulfate-polyacrylamide gels by blotting them onto a damaged DNA-fixed membrane is presented. To prepare the membrane, highly polymerized calf thymus DNA immobilized on a nylon membrane is damaged chemically. Enzymes, either homogeneous or crude, that are possibly involved in the priming step of DNA repair are fractionated by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and are renatured to active form by incubating the gel in an appropriate buffer. The renatured enzyme is then blotted onto the damaged DNA-fixed membrane, a process during which incision and/or excision are introduced to the damaged DNA by the enzymes. The incision and/or excision provide priming sites for repair DNA synthesis in the subsequent step in which the membrane is incubated with DNA polymerase in the presence of alpha-{sup 32}P-labeled substrate. The site of substrate incorporation on the membrane reflecting the molecular weight of the repair enzyme is finally visualized by autoradiography. The present technique is established using Escherichia coli exonuclease III and a DNA-fixed membrane treated with bleomycin or acid-depurinated. By application of this method, a priming factor (an exonuclease) involved in the initiation of bleomycin-induced DNA repair is detected in the extract of mouse ascites sarcoma cells, and thus the molecular weight of the enzyme is estimated. Some apurinic/apyrimidinic endonucleases of mammals are also detected by the present procedure.

Ikeda, S.; Seki, S.; Watanabe, S.; Hatsushika, M.; Tsutsui, K. (Department of Biochemistry, Okayama University Medical School (Japan))

1991-01-01

118

An excimer-based, turn-on fluorescent sensor for the selective detection of diphosphorylated proteins in aqueous solution and polyacrylamide gels.  

PubMed

Protein phosphorylation is a ubiquitous post-translational modification, which often acts as a switch to proteins' activation and is frequently perturbed in diseases. Although many general phospho-protein detection tools are available, none of them offers information about the relative spatial arrangement of phosphorylated residues. Specifically, proximally phosphorylated residues are hallmarks of certain activated disease-relevant proteins. We herein report the first turn-on fluorescent sensor for the selective detection of proximally phosphorylated protein sites, suitable for application in both aqueous solutions and polyacrylamide gels. PMID:24387313

Kraskouskaya, Dziyana; Bancerz, Matthew; Soor, Harjeet S; Gardiner, Jordan E; Gunning, Patrick T

2014-01-29

119

Fluid diversion and sweep improvement with chemical gels in oil recovery processes. [Four types of gels: resorcinol-formaldehyde; colloidal silica; Cr sup 3+ (chloride)-xanthan; and Cr sup 3+ (acetate)-polyacrylamide  

SciTech Connect

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

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

1992-09-01

120

Separation of metalloproteins using a novel metal ion contaminant sweeping technique and detection of protein-bound copper by a metal ion probe in polyacrylamide gel electrophoresis: distribution of copper in human serum.  

PubMed

A polyacrylamide gel electrophoresis (PAGE)-based method has been developed, consisting of two types of gel electrophoresis, to obtain an accurate distribution of protein-bound metal ions in biological samples. First, proteins are separated by PAGE without the uptake of contaminant metal ions in the separation field and dissociation of metal ions from the proteins. This is followed by another PAGE for the separation and detection of protein-bound metal ions in small volume samples with high sensitivity in the ppt range using a fluorescent metal probe. The former is a new technique using blue-native (BN) PAGE to electrophoretically sweep all metal contaminants by employing two kinds of chelating agents. These agents form complexes with contaminants in the gel and the separation buffer solution, which migrate towards opposite pole directions, thus lowering the contaminants to below the ppt level during separation. This is termed "Metal Ion Contaminant Sweeping BN-PAGE (MICS-BN-PAGE)". After the separation of proteins under these first metal-free conditions, the metal ions in the gel fractions are eluted, followed by derivatization of copper ions into the metal probe complexes to be separated and determined by fluorescence detection in the second PAGE. In this PAGE-based method, the copper ions bound to ceruloplasmin and superoxide dismutase were quantitatively determined, in addition to the exchangeable albumin-bound copper ions. This system successfully provided distribution maps of protein-copper in human serum. The precise distribution of copper in human serum was investigated, and found to be different from that which is widely accepted. PMID:23964357

Saito, Shingo; Kawashima, Mitsuyoshi; Ohshima, Hiroki; Enomoto, Kazuki; Sato, Makoto; Yoshimura, Hajime; Yoshimoto, Keitaro; Maeda, Mizuo; Shibukawa, Masami

2013-10-21

121

Mechanism of smectic arrangement of montmorillonite and bentonite clay platelets incorporated in gels of poly(acrylamide) induced by the interaction with cationic surfactants.  

PubMed

Structure transitions, induced by the interaction with the cationic surfactant cetylpyridinium chloride in nanocomposite gels of poly(acrylamide) with incorporated suspensions of the two closely related layered clays bentonite and montmorillonite, were studied. Unexpectedly, different behaviors were revealed. X-ray diffraction measurements confirm that, due to the interaction with the surfactant, initially disordered bentonite platelets arrange into highly ordered structures incorporating alternating clay platelets and surfactant bilayers. The formation of these smectic structures also in the cross-linked polymer gels, upon addition of the surfactant, is explained by the existence of preformed, poorly ordered aggregates of the clay platelets in the suspensions before the gel formation. In the case of montmorillonite, smectic ordering of the disordered platelets in the presence of the surfactant is observed only after drying the suspensions and the clay-gel composites. Rheology studies of aqueous suspensions of the two clays, in the absence of both surfactant and gel, evidence a much higher viscosity for bentonite than for montmorillonite, suggesting smaller clay-aggregate size in the latter case. Qualitatively consistent results are obtained from optical micrographs. PMID:16378447

Starodoubtsev, S G; Lavrentyeva, E K; Khokhlov, A R; Allegra, G; Famulari, A; Meille, S V

2006-01-01

122

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting analysis of smooth-lipopolysaccharide heterogeneity among Brucella biovars related to A and M specificities.  

PubMed Central

Smooth (S)-lipopolysaccharide (LPS) preparations from reference and field strains of several biovars of Brucella abortus, B. melitensis, and B. suis were prepared by (i) the hot phenol-water method, (ii) hot sodium dodecyl sulfate extraction and proteinase K digestion, or (iii) dimethyl sulfoxide extraction. These S-LPS-enriched fractions were further analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining after periodate oxidation. Immunoblots were developed by using either monoclonal antibodies specific for Brucella A or M antigens or polyclonal polyspecific or monospecific sera from rabbits, cattle, and goats. The specificity of monoclonal antibodies reactive with Brucella unique (A or M) epitopes was demonstrated by enzyme-linked immunosorbent assay, LPS latex agglutination, or agglutination inhibition. The most-represented subunits of S-LPS ranged in Mr from 30,000 to 70,000 relative to marker proteins. According to A or M immunodominance, two sodium dodecyl sulfate-polyacrylamide gel electrophoresis banding patterns were clearly distinguished among biovars, whatever the fraction tested: a close succession of regularly spaced narrow bands for A greater than M strains and regularly spaced triplets of bands including either (i) a first thin band followed by two thick bands for B. abortus M greater than A strains or (ii) one thick band between two thin bands for B. melitensis or B. suis M greater than A strains. Moreover, A and M specificities were reaffirmed by sandwich enzyme immunoassay and latex agglutination inhibition with monoclonal antibodies and polyclonal sera. Images

Garin-Bastuji, B; Bowden, R A; Dubray, G; Limet, J N

1990-01-01

123

Mono(adenosine diphosphate ribosyl) transferase in Xenopus tissues. Direct demonstration by a zymographic localization in sodium dodecyl sulfate--polyacrylamide gels.  

PubMed

A semiquantitative method to measure mono(adenosine diphosphate ribosyl) transferase activity [mADPRT] in tissue extracts is described. After electrophoretic separation in sodium dodecyl sulfate (SDS)--polyacrylamide gels, renatured enzymatic activity is demonstrated in situ by incubation of the slab gels with radiolabeled NAD+ and histones. Precipitation of the radiolabeled product in the gel allows localization of the enzyme by autoradiography. This method is suitable for two-dimensional gel electrophoresis, whereby proteins are electrofocused in the presence of 9 M urea and subsequently subjected to electrophoresis in SDS. A single major band showing mADPRT activity of Mr approximately 30 Kda was observed in all crude extracts of Xenopus tissues examined. Accumulation of acid-insoluble radiolabeled products was dependent on added histones and was specifically inhibited by agmatine. The ADPRT activity of cholera toxin A fragment could also be demonstrated by this technique. Reducing agents stimulated the activity of cholera toxin A fragment while depressing that of Xenopus mADPRT. PMID:6329028

Godeau, F; Belin, D; Koide, S S

1984-03-01

124

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

PubMed

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

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

1999-06-01

125

Detection of rotavirus by hybridization with a nonradioactive synthetic DNA probe and comparison with commercial enzyme immunoassays and silver-stained polyacrylamide gels.  

PubMed Central

Three enzyme-linked immunosorbent assays (ELISAs) (rotavirus enzyme immunoassay [EIA; International Diagnostic Laboratories], Pathfinder [Kallestad Laboratories], and Rotaclone [Cambridge Bioscience, Inc.]) and hybridization of viral RNA with a nonradioactive, synthetic oligonucleotide DNA probe (SNAP; Molecular Biosystems, Inc.) were compared with silver-stained polyacrylamide gel electrophoresis (PAGE) of viral RNA for the detection of rotavirus in fecal specimens. Hybridization was performed following column purification of the viral RNA. Of 286 specimens analyzed by PAGE, SNAP, rotavirus EIA, Pathfinder, and Rotaclone, 88 were positive by PAGE. All 88 specimens were also positive by the other four assays. Nine specimens that were positive by one or more of the assays were positive by blocking ELISAs but were negative by PAGE. If these nine specimens were considered to be true positives, the final sensitivities and specificities were as follows: PAGE, 91 and 100%; SNAP, 94 and 97%; rotavirus EIA, 96 and 97%; Pathfinder, 100 and 94%; and Rotaclone, 96 and 97%, respectively.

Arens, M; Swierkosz, E M

1989-01-01

126

Determination of the molecular weight of human gamma-3 chains by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate  

PubMed Central

The molecular weights (mol. wt) for heavy chains of human IgG were estimated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. Polyclonal IgG and monoclonal IgG proteins of different subclasses were extensively reduced with 50 mM dithioerythritol, in the presence of 2 per cent sodium dodecyl sulphate, at 100°. Four control proteins of known mol. wt (cytochrome C, chymotrypsinogen A, egg albumin, and serum albumin) were used to construct a linear plot of electrophoretic mobility versus log mol. wt. From this plot, the following mol. wts were calculated: 53,650±700 for polyclonal IgG; 54,200±1065 for ?1, ?2, and ?4 chains, and 60,950±585 for ?3 chains. Those results confirm the larger size of ?3 chains reported by Saluk and Clem (1971).

Virella, G.; Parkhouse, R. M. E.

1972-01-01

127

Resolution of DNA in the presence of mobility modifying polar and nonpolar compounds by discontinuous electrophoresis on rehydratable polyacrylamide gels.  

PubMed

Ultrathin-layer rehydratable gels were surface loaded and run in the horizontal position to study effects of mobility modification of DNA. Mobility modification of DNA fragments was achieved by the addition of nonpolar monosaccharides and their corresponding sugar alcohols as well as with glycerol and ethylene glycol in the leading ion buffer. These compounds show little effect when included in the trailing ion buffer. Disaccharides show no mobility modification. Trailing ions such as serine and members of the Good buffer series reduced also the RF of double- or single-stranded DNA. While beta-alanine had no effect, serine and members of the Good buffer series, particularly MOPSO, showed a marked ability to decrease the RF; presumably due to changing the unstacking limits. Rapid separation of sequencing gels with high resolution was achieved with discontinuous buffer systems. The potential methodology for high-resolution scanning of gels as DNA zones unstack from the moving boundary is suggested. PMID:8512948

Allen, R C; Budowle, B; Reeder, D J

1993-01-01

128

Preliminary studies on the role and reactions of tetrakis(hydroxymethyl)phosphonium chloride in polyacrylamide gel dosimeters  

NASA Astrophysics Data System (ADS)

A major source of dosimetric inaccuracy in normoxic polymer gel dosimeters is local variations in the concentration of oxygen scavenger. Currently, a phosphorus compound, tetrakis(hydroxymethyl)phosphonium chloride (THPC), is the oxygen scavenger of choice in most polymer gel dosimetry studies. Reactions of THPC in a gel dosimeter are not limited to oxygen. It can possibly be consumed in reacting with gelling agent, water free-radicals and polymer radicals before, during and after irradiation, hence affecting the dose response of the dosimeter in several ways. These reactions are not fully known or understood. It is our hypothesis that THPC not only scavenges radical species but also modifies the morphology of the gelatin network and of the polymer, possibly by intervening in the polymerization of monomers. These hypotheses are investigated in an anoxic acrylamide-based gel dosimeter. Scanning electron microscopy results indicate gelatin pores decreasing from 70 to 40 µm and a very different radiation-induced polymer structure in samples containing THPC; Fourier-transform Raman spectroscopy shows a two-fold reduction in the dose constants of monomer consumption; however, a significant change in the relative dose constants of monomer consumption as a function of dose could not be detected.

Sedaghat, Mahbod; Bujold, Rachel; Lepage, Martin

2012-10-01

129

Diffusion blotting for rapid production of multiple identical imprints from sodium dodecyl sulfate polyacrylamide gel electrophoresis on a solid support.  

PubMed

A very simple and fast method for diffusion blotting of proteins from precast SDS-PAGE gels on a solid plastic support was developed. Diffusion blotting for 3 min gave a quantitative transfer of 10% compared with 1-h electroblotting. For each subsequent blot from the same gel a doubling of transfer time is necessary to obtain the same amount of protein onto each blot. The relative transfer of low and high molecular weight components was similar in diffusion and electroblotting. However, both methods do give a higher total transfer of the low molecular weight proteins compared with the large proteins. The greatest advantage of diffusion blotting is that several blots can be made from each lane, thus enabling testing of multiple antisera on virtually identical blots. The gel remains on the plastic support, which prevents it from stretching or shrinking. This ensures identical blots and facilitates more reliable molecular weight determination. Furthermore, the proteins remaining in the gel can be stained with Coomassie Brilliant Blue or other methods for exact and easy comparison with the developed blots. These advantages make diffusion blotting the method of choice when quantitative protein transfer is not required. PMID:19378042

Olsen, Ingrid; Wiker, Harald G

2009-01-01

130

Preliminary studies on the role and reactions of tetrakis(hydroxymethyl)phosphonium chloride in polyacrylamide gel dosimeters.  

PubMed

A major source of dosimetric inaccuracy in normoxic polymer gel dosimeters is local variations in the concentration of oxygen scavenger. Currently, a phosphorus compound, tetrakis(hydroxymethyl)phosphonium chloride (THPC), is the oxygen scavenger of choice in most polymer gel dosimetry studies. Reactions of THPC in a gel dosimeter are not limited to oxygen. It can possibly be consumed in reacting with gelling agent, water free-radicals and polymer radicals before, during and after irradiation, hence affecting the dose response of the dosimeter in several ways. These reactions are not fully known or understood. It is our hypothesis that THPC not only scavenges radical species but also modifies the morphology of the gelatin network and of the polymer, possibly by intervening in the polymerization of monomers. These hypotheses are investigated in an anoxic acrylamide-based gel dosimeter. Scanning electron microscopy results indicate gelatin pores decreasing from 70 to 40 µm and a very different radiation-induced polymer structure in samples containing THPC; Fourier-transform Raman spectroscopy shows a two-fold reduction in the dose constants of monomer consumption; however, a significant change in the relative dose constants of monomer consumption as a function of dose could not be detected. PMID:22964826

Sedaghat, Mahbod; Bujold, Rachel; Lepage, Martin

2012-10-01

131

Binding of Ubiquitin Conjugates to Proteasomes as Visualized with Native Gels  

PubMed Central

Summary The proteasome is an ATP-dependent molecular machine that degrades proteins through the concerted activity of dozens of subunits. It is the yin to the ribosome’s yang, and together these entities mold the protein landscape of the cell. Native gels are generally superior to conventional and affinity purifications for the analytical resolution proteasomal variants, and have thus become a staple of proteasome work. Here we describe the technique of using native gels to observe proteasomes in complex with ubiquitin conjugates. We discuss the consequences of ubiquitin conjugate length and concentration on the migration of these complexes, the use of this mobility shift to evaluate the relative affinity of mutant proteasomes for ubiquitin conjugates, and the effects of deubiquitinating enzymes and competing ubiquitin binding proteins on the interactions of ubiquitin conjugates with the proteasome.

Elsasser, Suzanne; Shi, Yuan; Finley, Daniel

2013-01-01

132

The staining of acidic proteins on polyacrylamide gels: enhanced sensitivity and stability of "Stains-all" staining in combination with silver nitrate.  

PubMed

A number of acidic proteins, such as those found in bone and dentin, are poorly resolved on acrylamide gels using Coomassie blue or silver nitrate staining. The cationic dye Stains-all allows visualization and identification of these proteins due to their differential staining: highly acidic proteins stain blue and intact proteoglycans stain purple, whereas less acidic proteins stain pink. However, the use of Stains-all is limited due to relatively poor staining sensitivity and lack of stability to light. A procedure which addresses these deficiencies has been developed utilizing established protocols for Stains-all staining followed by silver nitrate incubation and development. In this way, phosphoproteins such as osteopontin, bone sialoprotein, dentin phosphophoryn, and other acidic glycoproteins are visualized at higher sensitivity (greater than fivefold) and staining stability than normally achieved with just Stains-all. The protocol stains a greater variety of proteins than a combined alcian blue/silver staining procedure previously described. Utilizing the Stains-all/silver protocol, porcine bone osteopontin, a protein not visualized by standard silver staining, can be observed in amounts as little as 0.25 ng on polyacrylamide gels. Furthermore, densitometric scans demonstrate that the staining intensity is proportional to osteopontin amount and can be used for quantification over a range from 0.25 to 50 ng. PMID:9299020

Goldberg, H A; Warner, K J

1997-09-01

133

Diffusion blotting for rapid production of multiple identical imprints from sodium dodecyl sulfate polyacrylamide gel electrophoresis on a solid support.  

PubMed

A simple and fast method for diffusion blotting of proteins from precast SDS-PAGE gels (0.5 mm) was developed. The efficiency of protein transfer was evaluated using 14C labelled proteins. Diffusion blotting for three minutes, gave a transfer of 10% compared to electroblotting. By doubling the transfer time for each subsequent imprint, four imprints were made from the same lane with similar amounts of protein transferred onto each imprint. With a transfer time of three minutes each, it was possible to obtain at least ten imprints with all the proteins visible in all the imprints. There was no detectable loss in resolution as compared to electroblotting. The method also works well with an immuno-detecting system. The number of imprints which can be obtained, is dependent on the sensitivity of the detection system and the amount of protein applied. The greatest advantage of diffusion blotting compared to electroblotting is that several imprints can be made from each lane, and different antisera can be tested on identical imprints. The gel remains on its plastic support which prevents it from stretching and compression; this ensures identical imprints and facilitates more reliable molecular mass determination. If only a few imprints are made, sufficient protein remains within the gel for general protein staining. These advantages make diffusion blotting the method of choice when quantitative protein transfer is not required. PMID:9839928

Olsen, I; Wiker, H G

1998-11-01

134

Application of PhastSystem to the resolution of bovine milk proteins on urea-polyacrylamide gel electrophoresis.  

PubMed

Optimal conditions were established for alkaline urea-PAGE using modified precast, ultrathin gradient gels on the automated PhastSystem. Profiles of milk proteins showed that the caseins and whey proteins resolved extremely well. Major bands were observed for alpha s1-casein and beta-casein, and alpha s2-casein appeared as a well-resolved doublet. In contrast, kappa-casein separated from other caseins as a faint doublet, and purified kappa-casein appeared as one major and one minor band. Whey proteins (serum albumin, alpha-lactalbumin, beta-lactoglobulin) separated into broad bands resolved from each other and from the caseins. Partially (40%) dephosphorylated whole casein showed multiple bands for alpha s1-casein and beta-casein at different levels of phosphorylation. Separation of genetic phenotypes was observed for beta-lactoglobulin A and B; alpha s1-casein A, B, and C; and beta-casein A, B, and C. Electrophoretic patterns of milk proteins extracted from cheese samples varied among the different types of cheeses. Our modified procedure provides researchers with a rapid technique to separate both caseins and whey proteins on the same urea gel according to their charge to mass ratios. PMID:1597574

Van Hekken, D L; Thompson, M P

1992-05-01

135

Native ordered structure of welan polysaccharide: conformational transitions and gel formation in aqueous dimethyl sulphoxide.  

PubMed

Welan, in aqueous solution, has "weak gel" properties analogous to those of ordered xanthan but, unlike xanthan, shows no evidence of conformational change between 0 and 100 degrees C. When the polymer is dissolved in dimethyl sulphoxide (Me2SO) rather than in water, however, there is a massive decrease in viscosity and total loss of gel-like character. In mixtures of the two solvents, the change in rheology occurs over a narrow range of composition (approximately 85-90% v/v Me2SO for 0.5% welan). On heating and cooling in a solvent close to the lower end of the critical range (86% Me2SO), the polymer shows typical order-disorder and disorder-order transitions [as monitored by optical rotation, differential scanning calorimetry, and temperature-course of rheological change]. When solutions of disordered welan in Me2SO are poured into excess water they form cohesive strings of gel. We interpret these results as showing that: (1) the stable conformation of welan in water is the double helix structure identified by X-ray fibre diffraction in the solid state; (2) in native welan, as biosynthesised, the strands are perfectly paired, and ordered along their full length; (3) on exposure to high concentrations of Me2SO, the native structure is dissociated into disordered coils; (4) rapid renaturation from the disordered state gives shorter helices, with exchange of partners to form a stable cross-linked network. PMID:8137361

Hember, M W; Richardson, R K; Morris, E R

1994-01-15

136

Mucosal toxicity studies of a gel formulation of native pokeweed antiviral protein.  

PubMed

Pokeweed antiviral protein (PAP), a 29-kDa plant-derived protein isolated from Phytolacca americana, is a promising nonspermicidal broad-spectrum antiviral microbicide. This study evaluated the mucosal toxicity potential of native PAP in the in vivo rabbit vaginal irritation model as well as the in vitro reconstituted human vaginal epithelial tissue model. Twenty-two New Zealand white rabbits in 4 subgroups were exposed intravaginally to a gel with and without 0.01, 0.1, or 1.0% native PAP for 10 consecutive days. The dose of PAP used represented nearly 200- to 20,000 times its in vitro anti-HIV IC50 value. Animals were euthanized on day 11 and vaginal tissues were evaluated for histologic and immunohistochemical evidence of mucosal toxicity, cellular inflammation, and hyperplasia. Blood was analyzed for changes in hematology and clinical chemistry profiles. Reconstituted human vaginal epithelial tissue grown on membrane filters was exposed to 0.01, 0.1, or 1.0% native PAP in medium or topically via a gel for 24 hours and tissue damage was evaluated by histological assessment. In the in vivo rabbit vaginal irritation model, half of all PAP-treated rabbits (8/16) exhibited an acceptable range of vaginal mucosal irritation (total score <8 out of a possible 16), whereas nearly a third of PAP-treated rabbits (5/16) developed moderate to marked vaginal mucosal irritation (total score >11). However, no treatment-related adverse effects were seen in hematological or clinical chemistry measurements. Furthermore, in vitro exposure of a 3-dimensional human vaginal tissue grown on polycarbonate membrane filters to identical concentrations of PAP either added to culture medium or applied topically via gel formulation did not result in direct toxicity as determined by histologic evaluation. These findings indicate careful monitoring of vaginal irritation will be required in the clinical development of PAP as a nonspermicidal microbicide. PMID:15200159

D'Cruz, Osmond J; Waurzyniak, Barbara; Uckun, Fatih M

2004-01-01

137

Dimethylformamide interferes with Coomassie dye staining of proteins on blue native gel electrophoresis.  

PubMed

Blue native gel electrophoresis (BN-PAGE) is used extensively for characterization of mitochondrial respiratory complexes and uses the binding of Coomassie brilliant blue G-250 to visualize proteins. Oxidative modification of sulfhydryl groups of such proteins can be evaluated by labeling with iodoacetamide conjugated to biotin (BIAM) and detected with streptavidin peroxidase on Western blots following BN-PAGE. However, dissolving BIAM in dimethylformamide, a recommended solvent, reduces Coomassie blue G staining to proteins during BN-PAGE. This interference is prevented by dissolving BIAM in dimethyl sulfoxide. Precautions in the use of the dye for protein staining subsequent to BIAM labeling are discussed. PMID:24662748

Raghupathy, V; Oommen, Anna; Ramachandran, Anup

2014-06-15

138

Gene Expression in the Pulp of Ripening Bananas' Two-Dimensional Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis of in Vitro Translation Products and cDNA Cloning of 25 Different Ripening-Related mRNAs  

Microsoft Academic Search

~ mRNA was extracted from the pulp and peel of preclimacteric (d O) bananas (Musa AAA group, cv Crand Nain) and those exposed to ethylene gas for 24 h and stored in air alone for a further 1 (d 2) and 4 d (d 5). Two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of in vitro translation products from the pulp and

Rosybel Medina-Suárez; Kenneth Manning; Jonathan Fletcher; Julia Aked; Colin R. Bird; Craham B. Seymour

139

Characterization of the osteogenic stromal cell line MN7: identification of secreted MN7 proteins using two-dimensional polyacrylamide gel electrophoresis, western blotting, and microsequencing.  

PubMed

Proteins secreted by the osteogenic stromal cell line MN7 were analyzed using two-dimensional polyacrylamide gel electrophoresis (PAGE), western blotting, immunodetection, and microsequencing. Trichloroacetic acid-precipitated proteins from the conditioned medium of MN7 cell cultures, harvested at different times of growth, were dissolved in denaturing and reducing sample buffer and separated in the first dimension according to isoelectric point and in the second dimension according to molecular weight. Protein patterns were visualized using silver staining. Among the 350 separated protein spots, we identified type I collagen, bone sialoprotein, osteonectin, and cathepsin B by western blotting and immunodetection using polyclonal antibodies. Osteocalcin could not be detected in the conditioned medium of MN7 cells. Furthermore, 15 MN7-specific protein spots were localized after comparison with two-dimensional PAGE patterns from the conditioned medium of the nonosteogenic stromal cell lines MM1 and MV1. Microsequencing of the internal peptides of five selected spots revealed three known proteins, namely the carboxyl-terminal propeptide of the alpha 2 chain of collagen type I, cathepsin L, and the tissue inhibitor of metalloproteinases-2, an 18 kilodalton peptide fragment from osteopontin that has not previously been described, and a novel glycosylated 85 kD protein with an average isoelectric point of 5.7. All identified proteins did not vary in presence between the different time points analyzed by two-dimensional PAGE. The use of two-dimensional PAGE to investigate the secreted proteins of MN7 cells will enable us to establish a complete protein data base of extracellular osteoblast-specific proteins. Furthermore, two-dimensional PAGE in combination with other techniques is a fast and accurate method for the identification of novel proteins that could function as markers in osteoblast differentiation and/or bone formation. PMID:8079665

Mathieu, E; Meheus, L; Raymackers, J; Merregaert, J

1994-06-01

140

A comparison of extracted proteins of isolates of Dermatophilus congolensis by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting.  

PubMed

Antigenic diversity within a collection of 18 isolates of Dermatophilus congolensis from different Continents was examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and by Western blotting with sera from cattle with clinical dermatophilosis using whole cell extracts obtained by three methods and one extract of extracellular products of D. congolensis. One of the methods involving the release of a lysostaphin-solubilized protein (LSP) of whole cells of D. congolensis revealed a number of discrete and easily-identifiable bands in SDS-PAGE which were found suitable for characterizing protein patterns and was, therefore, subsequently used for a comparative analysis of the proteins of all the D. congolensis isolates. Six electropherotypes (ET) of D. congolensis were identified among the 18 isolates using the protein profiles based on the presence of four protein bands at Molecular weights (MW) 62, 28, 17.4 and 16.4 kDa. The ETs were found among isolates from different animal species and from different sources with ET1 consisting of three bovine and two equine isolates; ET2, two bovine and three ovine isolates; ET3, two bovine isolates; ET4, two bovine isolates; ET5, one bovine and one ovine isolates and ET6, two bovine isolates. Immunoblotting of the extracts of D. congolensis isolates with sera from cattle with clinical dermatophilosis infection demonstrated protein bands of MW ranging from 9 kDa to 188 kDa. Sera from chronic dermatophilosis infection demonstrated a 28 kDa protein which was immunodominant in the LSP extracts of all the 18 isolates of D. congolensis tested while sera from mild infections demonstrated mainly the 62 kDa protein in the same extracts. However, many protein bands were demonstrated in surface membrane (TSMP) and extracellular protein extracts with sera from only mildly infected animals. The protein patterns observed in all isolates of D. congolensis revealed global antigenic similarities and distinct differences among isolates which could not be associated with either geographic, climatic or host factors. Also sera from infected animals from endemic regions of dermatophilosis could not differentiate isolates of D. congolensis. This suggests the possibility that such sera must have come from animals that had been infected by a multitude of D. congolensis strains present in the herd environment and strains an animal could have come across during the 'ritual' annual cross-country migration of the cattle herds. PMID:10466501

Makinde, A A; Gyles, C L

1999-07-01

141

Analysis of membrane protein complexes by blue native PAGE.  

PubMed

Blue native polyacryamide gel electrophoresis is a special case of native electrophoresis for high resolution separation of enzymatically active protein complexes from tissue homogenates and cell fractions. The method is powerful between 10 and 10,000 kDa. Also membrane protein complexes are separated well after solubilization of complexes with mild neutral detergents. The separation principle relies on binding of Coomassie blue G250 which provides negative charges to the surface of the protein. During migration to the anode, protein complexes are separated according to molecular mass and/or size and high resolution is obtained by the decreasing pore size of a polyacrylamide gradient gel. The principles of 2-dimensional blue native sodium dodecyl sulfate polyacrylamide gel electrophoresis are presented here together with a practical step-by-step guide to performing the method in the laboratory. PMID:17031799

Reisinger, Veronika; Eichacker, Lutz Andreas

2006-09-01

142

The influence of native porcine gastric mucus gel on hydrogen ion diffusion: the effect of potentially ulcerogenic agents.  

PubMed

Experiments were carried out to investigate the ability of native gastric mucus gels to retard hydrogen ion diffusion. Mucus held between two polycarbonate membrane filters in a diffusion cell, separating equimolar solutions of NaCl and HCl, significantly reduced the rate of hydrogen ion diffusion and increased the time for the mean hydrogen ion front to traverse the mucus compartment (lag time) when compared to an unstirred layer of saline (P less than 0.01). N-acetylcysteine, sodium taurodeoxycholate and acetylsalicylic acid significantly increased the diffusion rate (P less than 0.025); the lag time was significantly reduced by N-acetylcysteine (P less than 0.001). In addition mucus gels were found to have buffering capacity at a pH greater than 2. These observations suggest that native gastric mucus gels can retard hydrogen ion diffusion and that this retardation of diffusion is reduced by agents which are potentially damaging to the gastric mucosa. PMID:2867158

Turner, N C; Martin, G P; Marriott, C

1985-11-01

143

International Conference on Harmonisation; Guidance on Q4B Evaluation and Recommendation of Pharmacopoeial Texts for Use in the International Conference on Harmonisation Regions; Annex 10 on Polyacrylamide Gel Electrophoresis General Chapter; availability. Notice.  

PubMed

The Food and Drug Administration (FDA) is announcing the availability of a guidance entitled "Q4B Evaluation and Recommendation of Pharmacopoeial Texts for Use in the ICH Regions; Annex 10: Polyacrylamide Gel Electrophoresis General Chapter. The guidance was prepared under the auspices of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH). The guidance provides the results of the ICH Q4B evaluation of the Polyacrylamide Gel Electrophoresis General Chapter harmonized text from each of the three pharmacopoeias (United States, European, and Japanese) represented by the Pharmacopoeial Discussion Group (PDG). The guidance conveys recognition of the three pharmacopoeial methods by the three ICH regulatory regions and provides specific information regarding the recognition. The guidance is intended to recognize the interchangeability between the local regional pharmacopoeias, thus avoiding redundant testing in favor of a common testing strategy in each regulatory region. In the Federal Register of February 21, 2008 (73 FR 9575), FDA made available a guidance on the Q4B process entitled "Q4B Evaluation and Recommendation of Pharmacopoeial Texts for Use in the ICH Regions." PMID:20387318

2010-04-12

144

Water mobility and textural properties of native and hydroxypropylated wheat starch gels  

Microsoft Academic Search

The effect of wheat starch concentration and degree of hydroxypropylation on the water dynamics and textural attributes of starch gels was studied using 1H NMR and texture profile analysis. Starches were prepared with molar substitution (MS) of hydroxypropyl groups of 0.05, 0.12, and 0.18. Gels were formed from modified starches at concentrations between 25 and 40%. For all gels, two

S. G Choi; W. L Kerr

2003-01-01

145

Fluorescent staining of glycoproteins in sodium dodecyl sulfate polyacrylamide gels by 4H-[1]-benzopyrano[4,3-b]thiophene-2-carboxylic acid hydrazide.  

PubMed

A fluorescent detection method for glycoproteins in SDS-PAGE by using 4H-[1]-benzopyrano[4,3-b]thiophene-2-carboxylic acid hydrazide (BH) was developed in this study. As low as 4-8 ng glycoproteins (transferrin, ?1-acid glycoprotein) could be specifically detected by the BH staining method, which is twofold more sensitive than that of the most commonly used Pro-Q Emerald 488 glycoprotein stain. Furthermore, the specificity of the newly developed stain for glycoproteins was demonstrated by 1-D and 2-D SDS-PAGE, deglycosylation, glycoprotein affinity enrichment and LC-MS/MS, respectively. According to the results, it is concluded that BH stain may provide new choices for convenient, sensitive, specific and economic visualization of gel-separated glycoproteins. PMID:24712021

Zhu, Zhongxin; Zhou, Xuan; Wang, Yang; Chi, Lisha; Ruan, Dandan; Xuan, Yuanhu; Cong, Weitao; Jin, Litai

2014-06-01

146

Gene expression in the pulp of ripening bananas. Two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of in vitro translation products and cDNA cloning of 25 different ripening-related mRNAs.  

PubMed Central

mRNA was extracted from the pulp and peel of preclimacteric (d 0) bananas (Musa AAA group, cv Grand Nain) and those exposed to ethylene gas for 24 h and stored in air alone for a further 1 (d 2) and 4 d (d 5). Two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of in vitro translation products from the pulp and peel of these fruits revealed significant up-regulation of numerous transcripts during ripening. The majority of the changes were initiated by d 2, with the level of these messages increasing during the remainder of the ripening period. Pulp tissue from d 2 was used for the construction of a cDNA library. This library was differentially screened for ripening-related clones using cDNA from d-0 and d-2 pulp by a novel microtiter plate method. In the primary screen 250 up- and down-regulated clones were isolated. Of these, 59 differentially expressed clones were obtained from the secondary screen. All of these cDNAs were partially sequenced and grouped into families after database searches. Twenty-five nonredundant groups of pulp clones were identified. These encoded enzymes were involved in ethylene biosynthesis, respiration, starch metabolism, cell wall degradation, and several other key metabolic events. We describe the analysis of these clones and their possible involvement in ripening.

Medina-Suarez, R; Manning, K; Fletcher, J; Aked, J; Bird, C R; Seymour, G B

1997-01-01

147

Protein imprinting in polyacrylamide-based gels.  

PubMed

Protein imprinting in hydrogels is a method to produce materials capable of selective recognition and capture of a target protein. Here we report on the imprinting of fluorescently-labeled maltose binding protein (MBP) in acrylamide (AAm)/N-isopropylacrylamide (NIPAm) hydrogels. The targeting efficiency and selectivity of protein recognition is usually characterized by the imprinting factor, which in the simplest case is the ratio of protein uptake in an imprinted film divided by the uptake by the corresponding non-imprinted film. Our objective in this work is to study the dynamics of protein binding and elution in imprinted and non-imprinted films to elucidate the processes that control protein recognition. Protein elution from imprinted and non-imprinted films suggests that imprinting results in sites with a distribution of binding energies, and that only a relatively small fraction of these sites exhibit strong binding. PMID:25034963

Zayats, Maya; Brenner, Andrew J; Searson, Peter C

2014-10-01

148

Proteomic analysis of protein complexes in human SH-SY5Y neuroblastoma cells by using blue-native gel electrophoresis: an increase in lamin A/C associated with heat shock protein 90 in response to 6-hydroxydopamine-induced oxidative stress.  

PubMed

There is accumulating evidence that oxidative stress plays an important role in aging. Our previous phosphoproteomic study of the human neuroblastoma cell line SH-SY5Y revealed changes in the phosphorylation of several proteins such as lamin A/C during 6-hydroxydopamine-induced oxidative stress. The present study employed native proteomic analysis to clarify protein-protein interaction under physiological conditions. We examined oxidative stress-related changes in SH-SY5Y cellular proteins using blue-native polyacrylamide gel electrophoresis (BN-PAGE), a powerful tool for the separation of protein complexes. BN-PAGE gel images showed successful separation of several complexes. Components of these complexes, separated by 2-D BN-PAGE in combination with SDS-PAGE, were identified by peptide mass fingerprinting employing MALDI-TOF MS and an MS/MS ion search on LC-MS/MS. TCP-1 complex, ATP synthase, and the complex of heat shock protein 90 with its client proteins such as pyruvate kinase were detected. Two dimensional BN-PAGE and Western blot analysis revealed an increase of lamin A/C associated with heat shock protein 90 in response to 6-OHDA-induced oxidative stress. PMID:19264120

Nakamura, Megumi; Morisawa, Hiraku; Imajoh-Ohmi, Shinobu; Takamura, Chizuko; Fukuda, Hiroyuki; Toda, Tosifusa

2009-01-01

149

System for Gel Electrophoretic Immunoassay.  

National Technical Information Service (NTIS)

A micro-analytical platform for performing electrophoresis-based immunoassays was developed by integrating photopolymerized cross-linked polyacrylamide gels within a microfluidic device. The microfluidic immunoassays are performed by gel electrophoretic s...

A. E. Herr A. K. Singh D. J. Throckmorton

2005-01-01

150

Gel mobility shift assays to detect protein-RNA interactions.  

PubMed

The gel mobility shift assay is a powerful technique for detecting and quantifying protein-RNA interactions. While other techniques such as filter binding and isothermal titration calorimetry (ITC) are available for quantifying protein-RNA interactions, gel shift analysis provides the added advantage that you can visualize the protein-RNA complexes. In the gel shift assay, protein-RNA complexes are typically separated from the unbound RNA using native polyacrylamide gels in Tris/borate/EDTA buffer, although an alternative Tris-glycine buffering system is superior in many situations. Here, we describe both gel shift methods, along with strategies to improve separation of protein-RNA complexes from free RNA, which can be a particular challenge for small RNA binding proteins. PMID:22736005

Yakhnin, Alexander V; Yakhnin, Helen; Babitzke, Paul

2012-01-01

151

Application of rod-shaped cellulose nanocrystals in polyacrylamide hydrogels  

Microsoft Academic Search

Rod-shaped cellulose nanocrystals (CNCs) were manufactured and used to reinforce polyacrylamide (PAM) hydrogels through in situ free-radical polymerization. The gelation process of the nanocomposite hydrogels was monitored on a rheometer using oscillatory shear. The chemical structure, morphology, swelling property, and compression strength of the formed gels were investigated. A possible mechanism for forming hydrogels was proposed. The results showed that

Chengjun Zhou; Qinglin Wu; Yiying Yue; Quanguo Zhang

2011-01-01

152

Analysis of white spot syndrome virus envelope protein complexome by two-dimensional blue native\\/SDS PAGE combined with mass spectrometry  

Microsoft Academic Search

White spot syndrome virus (WSSV) is a large enveloped virus, but the organization of its envelope proteins remains largely\\u000a unknown. In the present study, we used blue native polyacrylamide gel electrophoresis (BN-PAGE) and SDS-PAGE in combination\\u000a with mass spectrometry to analyze the envelope protein complexome of WSSV. Our results show that the viral envelope consists\\u000a of multi-protein complexes (MPCs). Within

Zichong Li; Limei Xu; Fang Li; Qing Zhou; Feng Yang

2011-01-01

153

Method and Apparatus for Gel Electrophoretic Immunoassay.  

National Technical Information Service (NTIS)

A micro-analytical platform for performing electrophoresis-based immunoassays was developed by integrating photopolymerized cross-linked polyacrylamide gels within a microfluidic device. The microfluidic immunoassays are performed by gel electrophoretic s...

A. E. Herr A. K. Singh D. J. Throckmorton

2005-01-01

154

Horizontal polyacrylamide electrophoresis for the determination of serum protein (haptoglobin) and red cell enzyme polymorphisms  

Microsoft Academic Search

General and special procedures for the determination of serum (haptoglobin) and red cell enzyme polymorphisms by horizontal polyacrylamide (PAA) gel electrophoresis are given. As compared to starch gel techniques certain advantages could be established:1.Improved separation and reproducibility of the patterns using PAA.2.PAA gels are less sensitive to heating and desiccation during electrophoresis.3.PAA gels can be stored prior to use.4.PAA is

H. H. Hoppe; Windemut Hennig; B. Brinkmann

1972-01-01

155

Isoforms of a cuticular protein from larvae of the meal beetle, Tenebrio molitor, studied by mass spectrometry in combination with Edman degradation and two-dimensional polyacrylamide gel electrophoresis.  

PubMed Central

Simultaneous sequencing, using a combination of mass spectrometry and Edman degradation, of three approximately 15-kDa variants of a cuticular protein extracted from the meal beetle Tenebrio molitor larva is demonstrated. The information obtained by matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) time-course monitoring of enzymatic digests was found essential to identify the differences among the three variants and for alignment of the peptides in the sequence. To determine whether each individual insect larva contains all three protein variants, proteins extracted from single animals were separated by two-dimensional gel electrophoresis, electroeluted from the gel spots, and analyzed by MALDI MS. Molecular weights of the proteins present in each sample could be obtained, and mass spectrometric mapping of the peptides after digestion with trypsin gave additional information. The protein isoforms were found to be allelic variants.

Haebel, S.; Jensen, C.; Andersen, S. O.; Roepstorff, P.

1995-01-01

156

Microproteomic Analysis of 10,000 Laser Captured Microdissected Breast Tumor Cells Using Short-Range Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and Porous Layer Open Tubular (PLOT) LC-MS/MS  

PubMed Central

Precise proteomic profiling of limited levels of disease tissue represents an extremely challenging task. Here, we present an effective and reproducible microproteomic workflow for sample sizes of only 10,000 cells that integrates selective sample procurement via laser capture microdissection (LCM), sample clean up and protein level fractionation using short-range SDS-PAGE, followed by ultrasensitive LC-MS/MS analysis using a 10 ?m i.d. porous layer open tubular (PLOT) column. With 10,000 LCM captured mouse hepatocytes for method development and performance assessment, only 10% of the in-gel digest, equivalent to ~1000 cells, was needed per LC-MS/MS analysis. The optimized workflow was applied to the differential proteomic analysis of 10,000 LCM collected primary and metastatic breast cancer cells from the same patient. More than 1100 proteins were identified from each injection with >1700 proteins identified from three LCM samples of 10,000 cells from the same patient (1123 with at least two unique peptides). Label free quantitation (spectral counting) was performed to identify differential protein expression between the primary and metastatic cell populations. Informatics analysis of the resulting data indicated that vesicular transport and extracellular remodeling processes were significantly altered between the two cell types. The ability to extract meaningful biological information from limited, but highly informative cell populations demonstrates the significant benefits of the described microproteomic workflow.

Thakur, Dipak; Rejtar, Tomas; Wang, Dongdong; Bones, Jonathan; Cha, Sangwon; Clodfelder-Miller, Buffie; Richardson, Elizabeth; Binns, Shemeica; Dahiya, Sonika; Sgroi, Dennis; Karger, Barry L.

2011-01-01

157

Magnetic and spectroscopic properties of Polyacrylamide-CoFe2O4 magnetic hydrogel  

NASA Astrophysics Data System (ADS)

This study investigates synthesis and characterization of polyacrylamide (PAAm) hydrogels containing ferromagnetic CoFe2O4 nanoparticles. Structural, electrical, and magnetic characterization of the gels have been performed with X-ray powder diffractometry, Scanning electron microscopy, DC conductivity, magnetization and fluorescence spectroscopy techniques. Fluorescence and electrical measurements show that nanoparticles have trapped in the gel so they cannot move through the gel even if the gel is swollen and the voltage is applied. Pyranine molecules diffuse easily through the gel due to the presence of ferromagnetic nanoparticles. As number of diffused pyranine molecules increases current densities of the magnetic hydrogel increase. Magnetization measurements reveal that CoFe2O4 nanoparticles do not diffuse out of the gel during swelling. As a result, total magnetization of the gel do not change as volume of the gel increases.

Alvero?lu, E.; Sözeri, H.; Kurtan, U.; ?enel, M.; Baykal, A.

2013-03-01

158

Spring-loaded polymeric gel actuators  

DOEpatents

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

Shahinpoor, M.

1995-02-14

159

Templated native silk smectic gels  

NASA Technical Reports Server (NTRS)

One aspect of the present invention relates to a method of preparing a fibrous protein smectic hydrogel by way of a solvent templating process, comprising the steps of pouring an aqueous fibrous protein solution into a container comprising a solvent that is not miscible with water; sealing the container and allowing it to age at about room temperature; and collecting the resulting fibrous protein smectic hydrogel and allowing it to dry. Another aspect of the present invention relates to a method of obtaining predominantly one enantiomer from a racemic mixture, comprising the steps of pouring an aqueous fibrous protein solution into a container comprising a solvent that is not miscible with water; sealing the container and allowing it to age at about room temperature; allowing the enantiomers of racemic mixture to diffuse selectively into the smectic hydrogel in solution; removing the smectic hydrogel from the solution; rinsing predominantly one enantiomer from the surface of the smectic hydrogel; and extracting predominantly one enantiomer from the interior of the smectic hydrogel. The present invention also relates to a smectic hydrogel prepared according to an aforementioned method.

Jin, Hyoung-Joon (Inventor); Park, Jae-Hyung (Inventor); Valluzzi, Regina (Inventor)

2009-01-01

160

Polyacrylamide hydrogel differences: getting rid of the confusion.  

PubMed

Polymer hydrogels have been used for many years in European and Asian countries, and these products are often considered to be the same material in different packaging. This, however, is not the case. Performance and safety profiles depend on many factors including chemical and physical characteristics (including rheological properties), manufacturing process and control (cross linking, impurities, stability, etc.), injection technique, and interaction with surrounding tissues. Polyacrylamide hydrogel (PAAH) products, although often considered equal, have clear differences in composition, manufacturing, and injection technique as well as ability to interact with surrounding tissues, characteristics that determine the safety and effectiveness profiles of each of these gels. PMID:22134560

Narins, Rhoda S; Schmidt, Richard

2011-12-01

161

Relative Quantitative Comparisons of the Extracellular Protein Profiles of Staphylococcus aureus UAMS-1 and Its sarA, agr, and sarA agr Regulatory Mutants Using One-Dimensional Polyacrylamide Gel Electrophoresis and Nanocapillary Liquid Chromatography Coupled with Tandem Mass Spectrometry ? †  

PubMed Central

One-dimensional polyacrylamide gel electrophoresis followed by nanocapillary liquid chromatography coupled with mass spectrometry was used to analyze proteins isolated from Staphylococcus aureus UAMS-1 after 3, 6, 12, and 24 h of in vitro growth. Protein abundance was determined using a quantitative value termed normalized peptide number, and overall, proteins known to be associated with the cell wall were more abundant early on in growth, while proteins known to be secreted into the surrounding milieu were more abundant late in growth. In addition, proteins from spent media and cell lysates of strain UAMS-1 and its isogenic sarA, agr, and sarA agr regulatory mutant strains during exponential growth were identified, and their relative abundances were compared. Extracellular proteins known to be regulated by the global regulators sarA and agr displayed protein levels in accordance with what is known regarding the effects of these regulators. For example, cysteine protease (SspB), endopeptidase (SspA), staphopain (ScpA), and aureolysin (Aur) were higher in abundance in the sarA and sarA agr mutants than in strain UAMS-1. The immunoglobulin G (IgG)-binding protein (Sbi), immunodominant staphylococcal antigen A (IsaA), IgG-binding protein A (Spa), and the heme-iron-binding protein (IsdA) were most abundant in the agr mutant background. Proteins whose abundance was decreased in the sarA mutant included fibrinogen-binding protein (Fib [Efb]), IsaA, lipase 1 and 2, and two proteins identified as putative leukocidin F and S subunits of the two-component leukotoxin family. Collectively, this approach identified 1,263 proteins (matches of two peptides or more) and provided a convenient and reliable way of identifying proteins and comparing their relative abundances.

Jones, Richard C.; Deck, Joanna; Edmondson, Ricky D.; Hart, Mark E.

2008-01-01

162

Investigations on preparation and properties of modified polyacrylamide hydrogels for application as wound dressing materials.  

PubMed

Investigations on the influence of the polymerization conditions and feed ratio as well as various modification of the composite polyacrylamide-agar hydrogels on their properties has been presented. Results of the model studies have been utilized in the optimalization of the manufacturing parameters and procedures of the preparation of hydrogel dressing foils and granulated dressing gels. PMID:7479424

Lukaszczyk, J

1995-01-01

163

Polyacrylamide phantom for self-actuating needle-tissue interaction studies.  

PubMed

This study presents a polyacrylamide gel as a phantom material for needle insertion studies specifically developed for self-actuating needles to enhance the precise placement of needles in prostate. Bending of these self-actuating needles within tissue is achieved by Nitinol actuators attached to the needle body; however these actuators usually involve heating that can thermally damage the tissue surrounding the needles. Therefore, to develop and access feasibility of these needles, a polyacrylamide gel has been developed that mimics the thermal damage and mechanical properties of prostate tissue. Mechanical properties of the polyacrylamide gel was controlled by varying the concentrations of acrylamide monomer and N,N-methylene-bisacrylamide (BIS) cross-linker, and thermal sensitivity was achieved by adding bovine serum albumin (BSA) protein. Two polyacrylamide gels with different concentrations were developed to mimic the elastic modulus of the tissue. The two phantoms showed different rupture toughness and different deflection of bevel-tip needle. To study the thermal damage, a Nitinol wire was embedded in the phantom and resistively heated. The measured opaque zone (0.40mm) formed around the wire was close to the estimated damage zone (0.43mm) determined using the cumulative equivalent minutes at 43°C. PMID:23932314

Datla, Naresh V; Konh, Bardia; Koo, Joe J Y; Choi, Daniel J W; Yu, Yan; Dicker, Adam P; Podder, Tarun K; Darvish, Kurosh; Hutapea, Parsaoran

2014-01-01

164

Cationic Polyacrylamide Adsorption on Epoxy Surfaces  

Microsoft Academic Search

The adsorption of a cationic polyacrylamide (acrylamide\\/?-methacryloxyethyltrimethylammonium methyl sulfate copolymer) onto an imidazole catalyzed bisphenol-A based epoxy resin surface was examined by surface wetting. The work of adhesion of diodomethane, ethylene glycol and water was measured on microscopically smooth epoxy surfaces using a Wilhemy plate method, in both advancing and receding modes. The cationic polyacrylamide was adsorbed from aqueous solutions

Anastasios P. Angelopoulos; Jay B. Benziger; Sheldon P. Wesson

1997-01-01

165

SDS agarose gels for analysis of proteins.  

PubMed

A new agarose-based protein electrophoresis gel system is described. The system consists of a highly resolving agarose, MetaPhor XR (FMC BioProducts, Rockland, ME, USA) dissolved in urea and TBE buffer and a stacking gel composed of a high gel-strength agarose, SeaKem Gold (FMC BioProducts). TBE containing sodium dodecyl sulfate (SDS) is used as electrophoresis buffer. The disadvantages of traditional agarose gels have been overcome, and several advantages over polyacrylamide gels have been demonstrated. The system is capable of high-resolution separation of small proteins and has a dynamic separation range equivalent to a 4%-20% gradient polyacrylamide gel. Furthermore, the staining of protein bands by Coomassie Brilliant Blue is very uniform in this gel, and depending on the protein, higher detection sensitivity can be obtained compared to SDS polyacrylamide gels. In Western blotting, proteins are more efficiently transferred to the membrane from the agarose gel than from polyacrylamide gels. Finally, the exceptional stability of agarose allows for gels to be precast and stored for a year. PMID:9564543

Wu, M; Kusukawa, N

1998-04-01

166

The supramolecular structure of the GPCR rhodopsin in solution and native disc membranes  

PubMed Central

Summary Rhodopsin, the prototypical G-protein-coupled receptor, which is densely packed in the disc membranes of rod outer segments, was proposed to function as a monomer. However, a growing body of evidence indicates dimerization and oligomerization of numerous G-protein-coupled receptors, and atomic force microscopy images revealed rows of rhodopsin dimers in murine disc membranes. In this work we demonstrate by electron microscopy of negatively stained samples, blue native- and sodium dodecyl sulphate-polyacrylamide gel electrophoresis, chemical crosslinking, and by proteolysis that native bovine rhodopsin exists mainly as dimers and higher oligomers. These results corroborate the recent findings from atomic force microscopy and molecular modeling on the supramolecular structure and packing arrangement of murine rhodopsin dimers.

Suda, Kitaru; Filipek, Slawomir; Palczewski, Krzysztof; Engel, Andreas; Fotiadis, Dimitrios

2005-01-01

167

Single Quantum Dot Tracking in Heterogeneous Polyacrylamide Hydrogels  

NASA Astrophysics Data System (ADS)

Structural heterogeneity within polymer gels plays an important role in determining their material properties, yet is difficult to characterize by established methods. Single particle tracking measurements can provide highly localized information on the diffusion dynamics of tracer particles, and therefore on the material properties of the medium. We use tailored core-shell quantum dots (QDs) with hydrophilic ligands to characterize polyacrylamide hydrogels with varying crosslink density. We find that QDs show sub-diffusive behavior and non-Gaussian displacement distributions, consistent with prior reports on diffusive behavior in other heterogeneous media. We also consider the distribution of particle caging times, which is dictated by the potential energy barriers to escape pores, and therefore provides insight into structural heterogeneity. Specifically, we find that gels with a higher density of crosslinks yield broader distributions of caging times, indicating greater heterogeneity of these networks.

Lee, Cheol Hee; Crosby, Alfred; Hayward, Ryan; Emrick, Todd

2012-02-01

168

Nondenaturing electrophoresis of lipoproteins in agarose and polyacrylamide gradient gels.  

National Technical Information Service (NTIS)

The plasma lipoproteins frequently are classified according to density and/or electrophoretic mobility. The lipoprotein classes differ characteristically also in particle size and apolipoprotein composition. Each class is heterogeneous in size and composi...

V. G. Shore

1989-01-01

169

21 CFR 173.10 - Modified polyacrylamide resin.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 true Modified polyacrylamide resin. 173.10 Section 173.10 Food and Drugs...Treatment § 173.10 Modified polyacrylamide resin. Modified polyacrylamide resin may be safely used in food in accordance...

2010-01-01

170

21 CFR 173.10 - Modified polyacrylamide resin.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Modified polyacrylamide resin. 173.10 Section 173.10 Food and Drugs...Treatment § 173.10 Modified polyacrylamide resin. Modified polyacrylamide resin may be safely used in food in accordance...

2012-04-01

171

21 CFR 173.10 - Modified polyacrylamide resin.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Modified polyacrylamide resin. 173.10 Section 173.10 Food and Drugs...Treatment § 173.10 Modified polyacrylamide resin. Modified polyacrylamide resin may be safely used in food in accordance...

2011-04-01

172

21 CFR 173.10 - Modified polyacrylamide resin.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Modified polyacrylamide resin. 173.10 Section 173.10 Food and Drugs...Treatment § 173.10 Modified polyacrylamide resin. Modified polyacrylamide resin may be safely used in food in accordance...

2013-04-01

173

Cationic Polyacrylamide Adsorption on Epoxy Surfaces  

PubMed

The adsorption of a cationic polyacrylamide (acrylamide/beta-methacryloxyethyltrimethylammonium methyl sulfate copolymer) onto an imidazole catalyzed bisphenol-A based epoxy resin surface was examined by surface wetting. The work of adhesion of diodomethane, ethylene glycol and water was measured on microscopically smooth epoxy surfaces using a Wilhemy plate method, in both advancing and receding modes. The cationic polyacrylamide was adsorbed from aqueous solutions as a function of the pH of the solution. In addition to the cationic quaternary amine groups along the polymer chain, there were carboxylate groups from amide hydrolysis, which had a pKa of 10.73. The surface wetting of neither diodomethane nor ethylene glycol was sensitive to the adsorbed polyacrylamide. Wetting of the surface by water was very sensitive to the presence of adsorbed polyacrylamide. Polyacrylamides in solutions below pH 9 adsorbed onto the epoxy surface resulting in increased water adhesion to the surface. When the polyacrylamide solution was greater than pH 9 carboxylate groups ionized and the anions inhibited adsorption of the polyacrylamide. The water wetting measurements were shown to correlate with the adsorption of Pd/Sn colloidal particles used for electroless deposition of copper circuit lines on printed circuit boards. PMID:9056320

Angelopoulos; Benziger; Wesson

1997-01-01

174

Is a Cationic-Resin-Loaded Polymeric Gel a Better Antibacterial Material than a Nanosilver-Loaded Gel?  

Microsoft Academic Search

In this study, cationic-resin (Seralite SRC-120)-loaded poly(acrylamide) gels have been prepared by potassium-persulphate-initiated free radical polymerization of acrylamide in the presence of resin particles using methylene bisacrylamide as cross-linker. The resin-loaded hydrogel exhibited minimum swelling of 140%, while the maximum water uptake of 410% was found in plain poly(acrylamide) gels. The resinloaded gel has been investigated for its antibacterial action

Sutanjay Saxena; S. K. Bajpai

2010-01-01

175

Prototype for integrated two-dimensional gel electrophoresis for protein separation.  

PubMed

Two-dimensional gel electrophoresis practitioners have long waited for a fully automated system. This article presents an integrated platform that is capable of complete automation from sample introduction to spots detection. The strip gel for the first dimensional separation is fixed on the edge of a discrete planar stage before separation. A pair of platinum pin electrodes for isoelectric focusing (IEF) makes contact from underneath the stage. IEF is performed directly after rehydration and protein loading. After the first dimensional separation, sodium dodecyl sulfate (SDS) equilibration is done on the same stage without moving the gel. The IEF stage is then moved horizontally to couple with a precast second dimensional gel. The <0.5 mm gap between the two gels is filled with poly (ethylene oxide) solution. After SDS-polyacrylamide gel electrohporesis separation, a charge-coupled device camera is used to detect spots via protein native fluorescence excited by a Hg (Xe) lamp with the gel inside the running cell. Potential for full automation is demonstrated with 0.5 microg of Escherichia coli proteins on this miniaturized platform. More than 240 spots are detected in a total experiment time of <2.5 h. PMID:16130711

Xu, Aoshuang; Sluszny, Chanan; Yeung, Edward S

2005-09-16

176

Improving calibration accuracy in gel dosimetry  

Microsoft Academic Search

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 field end-on in a water bath, such that the characteristic depth-dose curve is recorded in the

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

1998-01-01

177

Visual optical biosensors based on DNA-functionalized polyacrylamide hydrogels.  

PubMed

Biosensors are devices that can provide quantitative or semi-quantitative analytical information about target molecules, where molecular recognition is based on biomolecular interactions. In recent years, DNA has emerged as a useful molecule for biosensor development since DNA can not only recognize its complementary strand, but also metal ions, small molecules, proteins and cells utilizing DNA aptamer technology. Converting DNA binding events into useful biosensors often require sensor immobilization. Among the various materials for sensor immobilization, hydrogels are particularly attractive. Hydrogels are crosslinked hydrophilic polymer networks that undergo swelling in water. In a gel, DNA immobilization can take place in 3D, allowing for high DNA loading capacity. Hydrogels are transparent, offering low optical background. The gel volume is affected by many environmental parameters such as temperature, pH, ionic strength, and solvent composition. In this paper, we present a concise summary of recent developments in DNA-functionalized hydrogel biosensors for visual detection. Detailed methods for immobilizing DNA biosensors in monolithic polyacrylamide gels and gel microparticles are supplied. PMID:23978515

Khimji, Imran; Kelly, Erin Y; Helwa, Youssef; Hoang, Michael; Liu, Juewen

2013-12-15

178

Multiple phases of protien gels  

Microsoft Academic Search

A multiple phase transition was observed in gels made by covalently cross-linking proteins in either native or denatured state. The enzymatic activity of the gels prepared from native alpha-chymotrypsin was determined for each of the multiple phases. The reversibility of the swelling degrees and the enzymatic reaction rates upon phase transition suggests that the protein is at a free energy

Masahiko Annaka; Toyoichi Tanaka

1994-01-01

179

Salt-induced changes in the plasma membrane proteome of the halotolerant alga Dunaliella salina as revealed by blue native gel electrophoresis and nano-LC-MS/MS analysis.  

PubMed

The halotolerant alga Dunaliella salina is a recognized model photosynthetic organism for studying plant adaptation to high salinity. The adaptation mechanisms involve major changes in the proteome composition associated with energy metabolism and carbon and iron acquisition. To clarify the molecular basis for the remarkable resistance to high salt, we performed a comprehensive proteomics analysis of the plasma membrane. Plasma membrane proteins were recognized by tagging intact cells with a membrane-impermeable biotin derivative. Proteins were resolved by two-dimensional blue native/SDS-PAGE and identified by nano-LC-MS/MS. Of 55 identified proteins, about 60% were integral membrane or membrane-associated proteins. We identified novel surface coat proteins, lipid-metabolizing enzymes, a new family of membrane proteins of unknown function, ion transporters, small GTP-binding proteins, and heat shock proteins. The abundance of 20 protein spots increased and that of two protein spots decreased under high salt. The major salt-regulated proteins were implicated in protein and membrane structure stabilization and within signal transduction pathways. The migration profiles of native protein complexes on blue native gels revealed oligomerization or co-migration of major surface-exposed proteins, which may indicate mechanisms of stabilization at high salinity. PMID:17569891

Katz, Adriana; Waridel, Patrice; Shevchenko, Andrej; Pick, Uri

2007-09-01

180

Electrically controlled polymeric gel actuators  

DOEpatents

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

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

1993-10-05

181

Electrically controlled polymeric gel actuators  

DOEpatents

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

Adolf, Douglas B. (Albuquerque, NM); Shahinpoor, Mohsen (Albuquerque, NM); Segalman, Daniel J. (Albuquerque, NM); Witkowski, Walter R. (Albuquerque, NM)

1993-01-01

182

The rheological behavior of polyacrylamide solution II. Yield stress  

Microsoft Academic Search

The effect of temperature and concentration on the rheological behavior of polyacrylamide solution was systematically studied using the generalized Casson equation. It was found that the yield stress of the polyacrylamide solution decreased with increasing temperature and increased with increasing concentration. The consistency coefficient of polyacrylamide solution increased and flow behavior index of polyacrylamide solution decreased on increasing the temperature.

Mu-Hoe Yang

2001-01-01

183

Determination of polyacrylamide in soil waters by size exclusion chromatography.  

PubMed

Determination of polyacrylamide (PAM) concentration in soil waters is important in improving the efficiency of PAM application and understanding the environmental fate of applied PAM. In this study, concentrations of anionic PAM with high molecular weight in soil waters containing salts and dissolved organic matter (DOM) were determined quantitatively by size exclusion chromatography (SEC) with ultraviolet (UV) absorbance detection. Polyacrylamide was separated from interferential salts and DOM on a polymeric gel column eluted with an aqueous solution of 0.05 M KH2PO4 and then detected at a short UV wavelength of 195 nm. Analysis of PAM concentrations in soil sorption supernatants, soil leachates, and water samples from irrigation furrow streams showed that SEC is an effective approach for quantifying low concentrations (0-10 mg L(-1)) of PAM in waters containing soil DOM and salts. The method has a lower detection limit of 0.02 microg and a linear response range of 0.2 to 80 mg L(-1). Precision studies gave coefficients of variation of < 1.96% (n = 4) for > 10 mg L(-1) PAM and < 12% (n = 3) for 0.2 to 3 mg L(-1) PAM. PMID:14535339

Lu, Jianhang; Wu, Laosheng; Gan, Jianying

2003-01-01

184

Detection of Polymorphisms of Human DNA by Gel Electrophoresis as Single-Strand Conformation Polymorphisms  

Microsoft Academic Search

We developed mobility shift analysis of single-stranded DNAs on neutral polyacrylamide gel electrophoresis to detect DNA polymorphisms. This method follows digestion of genomic DNA with restriction endonucleases, denaturation in alkaline solution, and electrophoresis on a neutral polyacrylamide gel. After transfer to a nylon membrane, the mobility shift due to a nucleotide substitution of a single-stranded DNA fragment could be detected

Masato Orita; Hiroyuki Iwahana; Hiroshi Kanazawa; Kenshi Hayashi; Takao Sekiya

1989-01-01

185

Native metals  

NASA Astrophysics Data System (ADS)

The occurrence of native metals and intermetallics (e.g., gold, silver, copper, iron, platinoids, nickel, lead, zinc, and indium) in various geological formations, such as meteorites, mountain rocks, and lunar rocks, is discussed. Data on the composition and forms of occurrence of native metals are presented; associations of native metals are identified. Some hypotheses concerning the origin of native metals are examined.

Novgorodova, Margarita Ivanovna

186

Adverse reactions following injection with a permanent facial filler polyacrylamide hydrogel (Aquamid): causes and treatment  

Microsoft Academic Search

Background  Polyacrylamide hydrogel (Aquamid), an atoxic non-immunogenic gel of the non-resorbable type, has gained widespread popularity as an injectable filler for facial augmentation. However, adverse events (AEs) have occurred, the nature of which seems obscure because of negative findings on culture and a pattern of foreign-body response on microscopy.Design  This is a prospective study of case reports provided by physicians injecting Aquamid

Lise Christensen; Vibeke Breiting; Jens Vuust; Estrid Hogdall

2006-01-01

187

Electrochemical and electromechanical properties of fully hydrolyzed polyacrylamide for applications in biomimetics  

NASA Astrophysics Data System (ADS)

This paper focuses on the development of fully hydrolyzed polyacrylamide (PAAM) hydrogel for applications in biomimetics. We present an analysis of the motion of actuators based on PAAM hydrogel in order to obtain the elementary background needed for the design of actuating devices based on this material, which has a high compatibility with living tissues. The gel properties are investigated, the electroactivity of the hydrogel is shown and a qualitative-quantitative study demonstrating the basics of motion of such actuators is presented.

Bassil, M.; El Tahchi, M.; Souaid, E.; Davenas, J.; Azzi, G.; Nabbout, R.

2008-10-01

188

Hybrid Gel Composed of Native Heart Matrix and Collagen Induces Cardiac Differentiation of Human Embryonic Stem Cells without Supplemental Growth Factors  

PubMed Central

Our goal was to assess the ability of native heart extracellular matrix (ECM) to direct cardiac differentiation of human embryonic stem cells (hESCs) in vitro. In order to probe the effects of cardiac matrix on hESC differentiation, a series of hydrogels was prepared from decellularized ECM from porcine hearts by mixing ECM and collagen type I at varying ratios. Maturation of cardiac function in embryoid bodies formed from hESCs was documented in terms of spontaneous contractile behavior and the mRNA and protein expression of cardiac markers. Hydrogel with high ECM content (75% ECM, 25% collagen, no supplemental soluble factors) increased the fraction of cells expressing cardiac marker troponin T, when compared with either hydrogel with low ECM content (25% ECM, 75% collagen, no supplemental soluble factors) or collagen hydrogel (100% collagen, with supplemental soluble factors). Furthermore, cardiac maturation was promoted in high-ECM content hydrogels, as evidenced by the striation patterns of cardiac troponin I and by upregulation of Cx43 gene. Consistently, high-ECM content hydrogels improved the contractile function of cardiac cells, as evidenced by increased numbers of contracting cells and increased contraction amplitudes. The ability of native ECM hydrogel to induce cardiac differentiation of hESCs without the addition of soluble factors makes it an attractive biomaterial system for basic studies of cardiac development and potentially for the delivery of therapeutic cells into the heart.

Duan, Yi; Liu, Zen; O'Neill, John; Wan, Leo Q.; Freytes, Donald O.; Vunjak-Novakovic, Gordana

2011-01-01

189

Acetyl CoA Carboxylase: Isolation and Characterization of Native Biotin Carboxyl Carrier Protein  

PubMed Central

A large form of biotin carboxyl carrier protein (BCCPL) has been isolated from extracts of Escherichia coli. It has a minimal molecular weight of 20,000, according to its behavior on sodium dodecylsulfate-polyacrylamide gel electrophoresis, and contains approximately 1 mol of biotin per 22,000 g of protein. BCCPL exhibits Km values, in the biotin carboxylase and transcarboxylase half-reactions of acetyl CoA carboxylase, of 2 × 10-7 M and 4 × 10-7 M, respectively; these values are 50-100 times lower than those obtained with smaller forms of BCCP previously isolated. Electrophoresis of crude extracts of E. coli indicates that the major biotin-containing protein migrates at the same rate as BCCPL, which suggests that BCCPL is the native form of BCCP in E. coli. Images

Fall, R. Ray; Nervi, A. M.; Alberts, Alfred W.; Vagelos, P. Roy

1971-01-01

190

Native Words, Native Warriors  

NSDL National Science Digital Library

Throughout World War I and World War II, American Indians were asked to join the United States armed forces. They served in many different campaigns, and in many different capacities, but perhaps one of the best known groups of American Indians were the "Code Talkers". The "Code Talkers" were asked to develop a way of transmitting secret messages using their own native languages, and they were tremendously successful. This beautifully designed and multi-layered site developed by the National Museum of the American Indian presents the voices of the "Code Talkers", along with other voices, all of which are combined seamlessly with historic images, graphics, and songs. Visitors will learn about the "Code Talkers" experiences in the military, their reintegration into society upon their return from war, and subsequent recognition by both the French and United States governments.

191

Multiple phases of protien gels  

NASA Astrophysics Data System (ADS)

A multiple phase transition was observed in gels made by covalently cross-linking proteins in either native or denatured state. The enzymatic activity of the gels prepared from native ?-chymotrypsin was determined for each of the multiple phases. The reversibility of the swelling degrees and the enzymatic reaction rates upon phase transition suggests that the protein is at a free energy minimum and thus in a phase.

Annaka, Masahiko; Tanaka, Toyoichi

1994-03-01

192

Microfabricated Polyacrylamide Devices for the Controlled Culture of Growing Cells and Developing Organisms  

PubMed Central

The ability to spatially confine living cells or small organisms while dynamically controlling their aqueous environment is important for a host of microscopy applications. Here, we show how polyacrylamide layers can be patterned to construct simple microfluidic devices for this purpose. We find that polyacrylamide gels can be molded like PDMS into micron-scale structures that can enclose organisms, while being permeable to liquids, and transparent to allow for microscopic observation. We present a range of chemostat-like devices to observe bacterial and yeast growth, and C. elegans nematode development. The devices can integrate PDMS layers and allow for temporal control of nutrient conditions and the presence of drugs on a minute timescale. We show how spatial confinement of motile C. elegans enables for time-lapse microscopy in a parallel fashion.

Gude, Sebastian; Recouvreux, Pierre; van Zon, Jeroen S.; Tans, Sander J.

2013-01-01

193

High gelled-electrolyte quality with polyacrylamide polymer: limitation of cycle-life through water loss  

NASA Astrophysics Data System (ADS)

A gelled-electrolyte battery, with lead?calcium grids and over-pressure valves, has to be well designed, accurately manufactured, and charged with an optimized charging system in order to obtain a reasonable lifetime. Besides this detail know-how, which is necessary to reach the present state-of-the-art, the following two factors are critical to performance: (i) gel quality and distribution; (ii) water loss and cycle-life. The gel stiffness as well as the distribution and the correct acid concentration, can be optimally adjusted by the addition of a polyacrylamide-emulsion polymer and a reduction in the silica component. A well monitored and consistent gel quality is important in achieving equal behaviour between all cells in the battery. Water-loss tests have shown that different charging methods result in different lifetimes, from 550 to 2000 cycles.

Pösch, Gerd

194

Conducting polymer electrodes for gel electrophoresis.  

PubMed

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 ?-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. PMID:24586761

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

2014-01-01

195

Swelling kinetics of microgels embedded in a polyacrylamide hydrogel matrix.  

PubMed

Composite hydrogels-macroscopic hydrogels with embedded microgel particles-are expected to respond to external stimuli quickly because microgels swell much faster than bulky gels. In this work, the kinetics of the pH-induced swelling of a composite hydrogel are studied using turbidity measurements. The embedded microgel is a pH- and thermosensitive poly(N-isopropylacrylamide-co-acrylic acid) microgel and the hydrogel matrix is polyacrylamide. A rapid pH-induced swelling of the embedded microgel particles is observed, confirming that composite hydrogels respond faster than ordinary hydrogels. However, compared with the free microgels, the swelling of the embedded microgel is much slower. Diffusion of OH(-) into the composite hydrogel film is identified as the main reason for the slow swelling of the embedded microgel particles, as the time of the pH-induced swelling of this film is comparable to that of OH(-) diffusion into the film. The composition of the hydrogel matrix does not significantly change the characteristic swelling time of the composite hydrogel film. However, the swelling pattern of the film changes with composition of the hydrogel matrix. PMID:24861868

Huang, Na; Guan, Ying; Zhu, X X; Zhang, Yongjun

2014-06-23

196

Synthesis of polymeric neoglycoconjugates based on N-substituted polyacrylamides.  

PubMed

Several types of polymeric glycoconjugates, N-substituted polyacrylamides, have been synthesized by the reaction of activated polymers with omega-aminoalkylglycosides: (i) (carbohydrate-spacer)n-polyacrylamide, 'pseudopolysaccharides'; (ii) (carbohydrate-spacer)n-phosphatidylethanolaminem-polyacrylamide, neoglycolipids, derivatives of phosphatidylethanolamine; (iii) (carbohydrate-spacer)n-biotin-polyacrylamide, biotinylated probes; (iv) (carbohydrate-spacer)n-polyacrylamide-(macroporous glass), affinity sorbents based on macroporous glass, covalently coated with polyacrylamide. An almost quantitative yield in the conjunction reaction makes it possible to insert in the conjugate a predetermined quantity of the ligand(s). Pseudopolysaccharides proved to be a suitable form of antigen for activation of polystyrene and poly(vinyl chloride) plates (ELISA) and nitrocellulose membranes (dot blot), being advantageous over traditional neoglycoproteins. Polyvalent glycolipids insert well in biological membranes: their physical properties, particularly solubility, can be changed in a desired direction. Biotinylated derivatives were used as probes for detection and analysis of lectins. PMID:8400823

Bovin, N V; Korchagina EYu; Zemlyanukhina, T V; Byramova, N E; Galanina, O E; Zemlyakov, A E; Ivanov, A E; Zubov, V P; Mochalova, L V

1993-04-01

197

Combination of native and denaturing PAGE for the detection of protein binding regions in long fragments of genomic DNA.  

PubMed

In traditional electrophoresis mobility shift assay (EMSA) a single (32)P-labeled double-stranded DNA oligonucleotide or a restriction fragment bound to a protein is separated from the unbound DNA by polyacrylamide gel electrophoresis (PAGE) under nondenaturing conditions. An extension of this method uses a population of DNA restriction fragments derived from long genomic regions for the identification of fragments containing protein binding regions. Although the method allows simultaneous analysis of large fragments, it is relatively laborious and can be used to detect only fragments containing high affinity protein binding sites. Here we describe an alternative and straightforward strategy which is based on a combination of native and denaturing PAGE. With this strategy restriction fragments, derived from genomic DNA (<10 kb), containing high as well as low affinity protein binding regions may be easily identified. PMID:23436361

Kaer, Kristel; Speek, Mart

2013-01-01

198

Effects of gel composition on the radiation induced density change in PAG polymer gel dosimeters: a model and experimental investigations  

Microsoft Academic Search

Due to a density change that occurs in irradiated polyacrylamide gel (PAG), x-ray computed tomography (CT) has emerged as a feasible method of performing polymer gel dosimetry. However, applicability of the technique is currently limited by low sensitivity of the density change to dose. This work investigates the effect of PAG composition on the radiation induced density change and provides

M. Hilts; A. Jirasek; C. Duzenli

2004-01-01

199

Diffusion in Polymer Gel Implants  

PubMed Central

Crosslinked polyacrylamide and polyvinylpyrrolidone gels have been used to subcutaneously implant 125I-labeled immunoglobulin, 125I-labeled luteinizing hormone, 125I-labeled bovine serum albumin, 125I-labeled insulin, [3H]prostaglandin F2?, and Na125I into hamsters. From the rates of absorption of the solutes, their diffusion coefficients were determined. The diffusion coefficients showed a logarithmic dependence on implant polymer concentration and solute molecular weight. Release of the solutes from gel preparations incubated 10 mM phosphate buffer (pH 7.2) at 37° revealed a similar relationship between solute diffusion coefficient, molecular weight, and the concentration of polymer. A general equation was derived that gives the expected diffusion coefficient of a substance in a polymer gel from its molecular weight, diffusion coefficient in solvent, and polymer concentration of the gel.

Davis, B. K.

1974-01-01

200

Native Networks  

NSDL National Science Digital Library

Over the past few years, Native Americans have made significant contributions in a host of different media, including television, radio, and film. Involved in all aspects of this type of artistic and cultural expression, many Native Americans have also looked for a way to disseminate their substantial efforts in this arena. Fortunately, there is the Native Networks website (first launched in 2001), designed to provide information about such creations. The website was created by the Film and Video Center of the National Museum of the American Indian, and contains information about upcoming Native American film festivals and âÂÂclose-upâ profiles of people actively working in the field. Some of these features include material on the indigenous video makers in Mexico and an in-depth look at the film âÂÂHouse Made of DawnâÂÂ, which deals with a young Pueblo man in crisis. The site is available in both Spanish and English versions. [KMG

201

Characterization of polyacrylamide based monolithic columns.  

PubMed

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

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

2004-07-01

202

Correlation between the spermatozoal characteristics and sperm penetration distance in polacrylamide gel and bovine cervical mucus  

Microsoft Academic Search

Correlation between the spermatozoal characteristics and the sperm penetration distance in polyacrylamide gel was assessed, utilizing frozen thawed semen samples obtained from 6 bulls, and it was compared with the correlation between sperm penetration in bovine cervical mucus and spermatozoal characteristics. In vitro sperm penetration tests were performed with mucus and gel. The sperm penetration in gel and mucus was

R. Anilkumar; T. G. Devanathan; S. R. Pattabiraman; M. John Edwin

2001-01-01

203

Evidence of native ?-synuclein conformers in the human brain.  

PubMed

?-Synuclein aggregation is central to the pathogenesis of several brain disorders. However, the native conformations and functions of this protein in the human brain are not precisely known. The native state of ?-synuclein was probed by gel filtration coupled with native gradient gel separation, an array of antibodies with non-overlapping epitopes, and mass spectrometry. The existence of metastable conformers and stable monomer was revealed in the human brain. PMID:24474688

Gould, Neal; Mor, Danielle E; Lightfoot, Richard; Malkus, Kristen; Giasson, Benoit; Ischiropoulos, Harry

2014-03-14

204

Effect of ?-carrageenan on volume phase transition for polyacrylamide (PAAm) hydrogel using the fluorescence technique  

NASA Astrophysics Data System (ADS)

Steady-state fluorescence (SSF) technique was employed for studying swelling of polyacrylamide (PAAm) gels with various content of ?-carrageenan ( ?C). Disc shaped composite hydrogels were prepared by free-radical crosslinking copolymerization of acrylamide (AAm) with various amounts ?C. N, N'-methylenebis (acrylamide) (BIS) and ammonium persulfate (APS) were used as crosslinker and initiator, respectively. Pyranine was introduced as a fluorescence probe. Fluorescence intensity of pyranine was monitored during in situ swelling processes of composite gels. It was observed that fluorescence intensity values decreased as swelling is proceeded. Li-Tanaka equation was used to determine the swelling time constants, ? and cooperative diffusion coefficients, D from intensity variations during the swelling processes. It was shown that swelling time constants, ? decreased and diffusion coefficients, D increased as the ?C content in the composites are increased.

Akta?, Demet Kaya

2014-03-01

205

Sequence-influenced interactions of oligoacridines with DNA detected by retarded gel electrophorectic migrations  

SciTech Connect

The authors have found that di-, tri-, tetra-, and hexa-9-acridinylamines are so efficiently associated with DNA during electrophoresis in polyacrylamide or agarose gels that they retard its migration. The retardation is roughly proportional to the reagent to base pair ratio, and the magnitude of the retardation indicates that a combined charge neutralization/helix extension mechanism is mainly responsible for the effect. Furthermore, DNA sequence dependent differences are observed. Thus, the pUC 19 restriction fragments (HaeIII or AluI), which in the native state comigrate upon gel electrophoretic analysis, could be separated in the presence of a diacridine, and specific DNA fragments responded differently to different diacridines. These results suggest that the effect also is due to a contribution from the DNA conformation and that the DNA conformation dynamics are influenced differently upon binding of different diacridines. They foresee three applications of this observation: (1) in analytical gel electrophoretic separation of otherwise comigrating DNA molecules, (2) in studies of polyintercalator-DNA interaction, and (3) in measurements of polyintercalator-induced DNA unwinding.

Nielsen, P.E.; Zhen, W.; Henriksen, U.; Buchardt, O.

1988-01-12

206

21 CFR 872.3480 - Polyacrylamide polymer (modified cationic) denture adhesive.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Polyacrylamide polymer (modified cationic) denture adhesive...Devices § 872.3480 Polyacrylamide polymer (modified cationic) denture adhesive. (a) Identification. A polyacrylamide polymer (modified cationic) denture...

2010-04-01

207

21 CFR 872.3420 - Carboxymethylcellulose sodium and cationic polyacrylamide polymer denture adhesive.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Carboxymethylcellulose sodium and cationic polyacrylamide...Devices § 872.3420 Carboxymethylcellulose sodium and cationic polyacrylamide...Identification. A carboxymethylcellulose sodium and cationic...

2009-04-01

208

21 CFR 872.3420 - Carboxymethylcellulose sodium and cationic polyacrylamide polymer denture adhesive.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Carboxymethylcellulose sodium and cationic polyacrylamide...Devices § 872.3420 Carboxymethylcellulose sodium and cationic polyacrylamide...Identification. A carboxymethylcellulose sodium and cationic...

2010-04-01

209

Adsorption of cationic polyacrylamide onto sepiolite.  

PubMed

The adsorption of PAM onto sepiolite from aqueous solutions has been investigated systematically as a function of some parameters such as calcination temperature of sepiolite, pH, ionic strength and temperature. The adsorption of cationic polyacrylamide (PAM) increases with pH from 5.50 to 11.00, temperature from 25 to 55 degrees C and ionic strength from 0 to 0.1molL(-1). The sepiolite sample calcined at 200 degrees C has a higher adsorption capacity than the other calcined samples. Adsorption isotherms of PAM onto sepiolite have been determined and correlated with common isotherm equations such as Langmuir and Freundlich isotherm models. The Langmuir isotherm model appeared to fit the isotherm data better than the Freundlich isotherm model. The physical properties of this adsorbent are consistent with the parameters obtained from the isotherm equations. The zeta potentials of sepiolite suspensions have been measured in aqueous solutions of NaCl and different PAM concentrations and pH. From the experimental results: (i) pH strongly alters the zeta potential of sepiolite, (ii) sepiolite has an isoelectric point at about pH 6.6 in water and about pH 8 in 250mgL(-1) PAM concentration, (iii) PAM changes the interface charge from negative to positive for sepiolite. Effect of temperature on adsorption has been quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy. The dimensionless separation factor (R(L)) has shown that sepiolite can be used for adsorption of PAM from aqueous solutions. PMID:16343759

Tekin, Nalan; Dinçer, Aziz; Demirba?, Ozkan; Alkan, Mahir

2006-06-30

210

In situ grouting of buried transuranic waste with polyacrylamide  

SciTech Connect

This project is a demonstration and evaluation of the in situ hydrologic stabilization of buried transuranic waste at a humid site via grout injection. Two small trenches, containing buried transuranic waste, were filled with 34.000 L of polyacrylamide grout. Initial field results have indicated that voids within the trenches were totally filled by the grout and that the intratrench hydraulic conductivity was reduced to below field-measurable values. No evidence of grout constituents were observed in twelve perimeter groundwater monitoring wells indicating that grout was contained completely within the two trenches. Polyacrylamide grout was selected for field demonstration over the polyacrylate grout due to its superior performance in laboratory degradation studies. Also supporting the selection of polyacrylamide was the difficulty in controlling the set time of the acrylate polymerization. Based on preliminary degradation monitoring, the polyacrylamide was estimated to have a microbiological half-life of 362 years in the test soil. 15 refs., 9 figs., 12 tabs.

Spalding, B.P.; Lee, S.Y.; Farmer, C.D.; Hyder, L.K.; Supaokit, P.

1987-01-01

211

Improving Infiltration of Irrigated Mediterranean Soils with Polyacrylamide  

Microsoft Academic Search

The effects of continuous (1·0 mg\\/l) and concentrated (10 mg\\/l) irrigation water-added polyacrylamide (PAM) on infiltration of a highly erodible Mediterranean soil were studied using recirculating furrow infiltrometers. Polyacrylamide avoided the seal formation observed in the wetted surface of the control furrow and helped to maintain higher infiltration rates for both PAM treatments. Mean final cumulative infiltration for the continuous

Francisco L. Santos; Ricardo P. Serralheiro

2000-01-01

212

Photoswitchable gel assembly based on molecular recognition  

PubMed Central

The formation of effective and precise linkages in bottom-up or top-down processes is important for the development of self-assembled materials. Self-assembly through molecular recognition events is a powerful tool for producing functionalized materials. Photoresponsive molecular recognition systems can permit the creation of photoregulated self-assembled macroscopic objects. Here we demonstrate that macroscopic gel assembly can be highly regulated through photoisomerization of an azobenzene moiety that interacts differently with two host molecules. A photoregulated gel assembly system is developed using polyacrylamide-based hydrogels functionalized with azobenzene (guest) or cyclodextrin (host) moieties. Reversible adhesion and dissociation of the host gel from the guest gel may be controlled by photoirradiation. The differential affinities of ?-cyclodextrin or ?-cyclodextrin for the trans-azobenzene and cis-azobenzene are employed in the construction of a photoswitchable gel assembly system.

Yamaguchi, Hiroyasu; Kobayashi, Yuichiro; Kobayashi, Ryosuke; Takashima, Yoshinori; Hashidzume, Akihito; Harada, Akira

2012-01-01

213

Molecular recognition in gels, monolayers, and solids  

NASA Astrophysics Data System (ADS)

This paper describes work in four areas: affinity electrophoresis of carbonic anhydrase in cross-linked polyacrylamide derived gels containing immobilized derivatives of aryl sulfonamides; inhibition of the hemagglutination of erythrocytes induced by influenza virus using water-soluble polyacrylamides bearing sialic acid groups; the application of self-assembled monolayers (SAMs) of alkyl thiolates on gold to the study of protein adsorption on organic surfaces; and the use of networks of hydrogen bonds to generate new classes of non-covalently assembled organic materials, both in solution and in crystals. This paper summarizes research in two areas of molecular recognition: affinity polymers and molecular self assembly. We illustrate these areas by examples drawn from affinity gel electrophoresis, soluble synthetic macromolecular inhibitors of binding of influenza virus to erythrocytes protein adsorption on self assembled monolayers and self assembling hydrogen bonded molecular aggregates.

Prime, Kevin L.; Chu, Yen-Ho; Schmid, Walther; Seto, Christopher T.; Chen, James K.

1991-12-01

214

Gel Electrophoresis  

NSDL National Science Digital Library

This interactive activity from the Dolan DNA Learning Center illustrates the process of gel electrophoresis, in which DNA fragments are separated by size as they migrate at different rates through a gel matrix.

Foundation, Wgbh E.

2007-04-19

215

Silver staining of 2D electrophoresis gels.  

PubMed

Silver staining is used to detect proteins after electrophoretic separation on polyacrylamide gels. It -combines excellent sensitivity (in the low nanogram range) with the use of very simple and cheap equipment and chemicals. For its use in proteomics, two important additional features must be considered, compatibility with mass spectrometry and quantitative response. Both features are discussed in this chapter, and optimized silver staining protocols are proposed. PMID:22665294

Rabilloud, Thierry

2012-01-01

216

Biomimetic alginate/polyacrylamide porous scaffold supports human mesenchymal stem cell proliferation and chondrogenesis.  

PubMed

We describe the development of alginate/polyacrylamide (ALG/PAAm) porous hydrogels based on interpenetrating polymer network structure for human mesenchymal stem cell proliferation and chondrogenesis. Three ALG/PAAm hydrogels at molar ratios of 10/90, 20/80, and 30/70 were prepared and characterized with enhanced elastic and rubbery mechanical properties, which are similar to native human cartilage tissues. Their elasticity and swelling properties were also studied under different physiological pH conditions. Finally, in vitro tests demonstrated that human mesenchymal stem cells could proliferate on the as-synthesized hydrogels with improved alkaline phosphatase activities. These results suggest that ALG/PAAm hydrogels may be a promising biomaterial for cartilage tissue engineering. PMID:25063162

Guo, Peng; Yuan, Yasheng; Chi, Fanglu

2014-09-01

217

Designing tissue phantoms for ultrasonography and elastography with TiO2 incorporated polyacrylamide hydrogels  

NASA Astrophysics Data System (ADS)

Research on ultrasonography and elastography instrumentation is crucially dependent on the quality of tissue-mimicking phantoms on which the instrumental parameters are tested. The phantoms should ideally possess values of various acoustic parameters corresponding to normal and abnormal tissues of different types and these properties should not change significantly with time. Designing such phantoms requires a molecular level understanding of the material to be used. In this context, polyacrylamide gels made from corresponding monomer, initiator and cross-linker were developed. An understanding of the network structure of these hydrogels at the molecular level was made possible using fluorescence spectroscopy with anilinonaphthylsulfonate as an extrinsic fluorescent probe. TiO2 was used to adjust the acoustic transparency so as to bring the ultrasound reflection parameters close to those of human tissues. It was found that the network structure of poly-acrylamide (PAM) hydrogels as well as their acoustic and viscoelastic properties could be conveniently varied by altering the composition of the components. This understanding at the molecular as well as the bulk level was then used to develop tissue phantoms appropriate for imaging in ultrasound-B and elastography modes.

Kumar, Kishore; Mohanty, Maneesha Esther; Jayashankar, V.; Suresh, S.; Mishra, Ashok K.

2012-07-01

218

Silk fibroin/polyacrylamide semi-interpenetrating network hydrogels for controlled drug release.  

PubMed

The present study describes a semi-interpenetrating network hydrogel fabricated using silk fibroin/polyacrylamide for controlled drug delivery applications. Hydrogels were synthesized using varied ratios of silk fibroin/acrylamide mixtures crosslinked by N,N'-Methylenebisacrylamide. Fourier-Transform Infrared analysis was performed suggesting beta sheet transition of silk fibroin with hydrogels. Scanning electron microscopy revealed microporous surface with maximum pore size of 50+/-11 microm. Rheological properties along with swellability, degradation, sol fraction estimation, equilibrium water content and swelling kinetics were evaluated. Compressive strength of 241.9+/-5.5 kPa was observed suggesting mechanically stronger gels. MTT assay showed biocompatibility and absence of deleterious effects of hydrogel on cell viability and functionality. In vitro release studies using two model compounds i.e. trypan blue dye and FITC-inulin reveal their sustained release from the fabricated hydrogel constructs. PMID:19203791

Mandal, Biman B; Kapoor, Sonia; Kundu, Subhas C

2009-05-01

219

Native genomic blotting: high-resolution mapping of DNase I-hypersensitive sites and protein-DNA interactions  

SciTech Connect

DNase I-hypersensitive sites are observed in the promoter regions of actively expressed genes, potentially active genes, and genes that were once active. The authors have developed an approach that greatly increases the resolution for mapping these sites by electrophoresing genomic DNA on native polyacrylamide gels prior to electroblotting and hybridization. This improved method has been used to scan the promoter and coding region of a cell-cycle-dependent human histone H4 gene with an accuracy of +/- 5-10 base pairs. Protein-DNA interactions can be seen in the autoradiograph as light areas and DNase I-hypersensitive sites as dark bands. Therefore, this method provides a rapid and relatively simple means to accurately localize protein-DNA interactions as well as DNase I-hypersensitive sites, thus directly displaying DNase I hypersensitivity and protein-DNA complexes on one autoradiograph. It also potentially allows the analysis of small changes in DNase I-hypersensitive sites under various biological conditions. With this technique rather large regions of DNA can be screened to determine areas that should be analyzed by more sophisticated methods, such as genomic sequencing or gel retardation assays.

Pauli, U.; Chrysogelos, S.; Stein, J.; Stein, G.

1988-01-01

220

Gel Electrophoresis  

NSDL National Science Digital Library

In the early days of DNA manipulation, DNA fragments were laboriously separated by gravity. In the 1970s, the powerful tool of DNA gel electrophoresis was developed. This process uses electricity to separate DNA fragments by size as they migrate through a gel matrix. This animation from Cold Spring Harbor Laboratory's Dolan DNA Learning Center presents Gel Electrophoresis through a series of illustrations of the processes involved.

2012-01-20

221

Adsorption and flocculation behavior of cationic polyacrylamide and colloidal silica  

Microsoft Academic Search

The adsorption of cationic polyacrylamide and silica nanoparticle systems onto a model surface has been compared with the adsorption and flocculation of a fiber suspension. An increase in ionic strength affects the polyelectrolyte adsorption in different ways in these two systems. With a silica surface, an increase in the ionic strength leads to a continuous increase in the adsorption. On

Daniel Solberg; Lars Wågberg

2003-01-01

222

Preparation and characterization of polyacrylamide-intercalated graphite oxide  

Microsoft Academic Search

Acrylamide-intercalated graphite oxide and polyacrylamide-intercalated graphite oxide nanocomposites have been prepared by exfoliation\\/absorption process and in situ polymerization method, respectively, and both characterized by X-ray diffraction. The results show that the polymerization process changed the orientation of the intercalated molecules.

Jiayan Xu; Yuan Hu; Lei Song; Qingan Wang; Weicheng Fan

2001-01-01

223

Polyacrylamide polymer viscosity as a function of brine composition  

Microsoft Academic Search

A computer model has been developed which predicts the viscosity of polymer and oil field brine mixtures. The polymers used were Amoco- Sweepaid 103 and Dow- Pusher 500 polyacrylamide polymers. All of the experiments were conducted at 1200 ppM polymer concentration. The computer input consists of the ionic strength of the brine in the mixture and the fraction of that

T. R. French; N. Stacy; A. G. Collins

1981-01-01

224

Polyacrylamide Polymer Viscosity as a Function of Brine Composition.  

National Technical Information Service (NTIS)

A computer model has been developed which predicts the viscosity of polymer and oil field brine mixtures. The polymers used were Amoco- Sweepaid 103 and Dow- Pusher 500 polyacrylamide polymers. All of the experiments were conducted at 1200 ppM polymer con...

A. G. Collins N. Stacy T. R. French

1981-01-01

225

Systematic Evaluation of Polyacrylamide for Sediment and Turbidity Control.  

National Technical Information Service (NTIS)

An evaluation of polyacrylamides (PAM) for sediment and turbidity control for construction sites was conducted in both the laboratory and the field. Field tests of PAM logs were conducted to determine the effects of log condition (wet or dry) and water te...

R. A. McLaughlin

2004-01-01

226

Biodegradation of Petroleum Hydrocarbons in a Soil Containing Polyacrylamide  

Microsoft Academic Search

The objective of this study was to evaluate the fate and toxicity of total petroleum hydrocarbons (TPH), polyacrylamide and acrylamide monomer in soil under aerobic conditions for mixtures of commercially available products that have application as an anti traction material (ATM) (Southwest Research Institute patent pending for ATM). The aerobic biodegradability of petroleum hydrocarbons in several formulations was determined using

Sameer Khaitan; L. E. Erickson; Stacy L. Hutchinson; R. Karthikeyan

227

FACTORS AFFECTING THE EFFICIENT FLOCCULATION OF TAILINGS BY POLYACRYLAMIDES  

Microsoft Academic Search

The flocculation of coal preparation plant tailings is an established technology, and the scientific basis of flocculation is well understood, Nevertheless, conditions specific to the preparation plant affect the efficiency of the process. The sedimentation rate obtained with flocculated tailings depends on the molecular size of the polyacrylamide. Modern flocculants are very high molecular weight polymers and the size of

J. M. HENDERSON; A. D. WHEATLEY

1987-01-01

228

Adsorption of sulfur dioxide by native clinoptilolite  

SciTech Connect

The purpose of the present work was to study the adsorption capacity of the little-studied native clinoptilolite from Beregovo in the Zakarpatskaya region (Ruthenia) for sulfur dioxide. Adsorption of SO/sub 2/ under analogous conditions by Patrick's silica gel, prepared by us by a known method, was studied for comparison. Results indicated that native clinoptilolite studied has much higher adsorption capacity than Patrick's silica gel for sulfur dioxide in the temperature range studied. The adsorption capacity of this zeolite alters little with increase of temperature in the range 25-75/sup 0/. It is considered that native clinoptilolite can be used for removing sulfur dioxide from waste gases in the temperature and pressure ranges studied.

Merkun, I.I.; Kel'tsev, N.V.; Bratchuk, F.N.; Rogovik, M.I.

1982-11-10

229

A simple method of eluting proteins from two-dimensional gels  

SciTech Connect

Apo A-I lipoprotein was extracted from the appropriate pieces of two-dimensional gel patterns, by electrophoresis onto hydroxylapatite overlaying a slab of polyacrylamide sodium dodecyl sulfate gel. The extracted protein was then eluted from the hydroxylapatite by washing with increasing concentrations of phosphate buffer. The recovered protein was electrophoretically homogeneous. We believe that this method can be generally useful in the purification, for study, of proteins identified on two-dimensional gels as putative markers of disease.

Guevara, J. (Texas Medical Center, Houston); Chiocca, E.A.; Clayton, F.C.; von Eschenbach, A.C.; Edwards, J.J.

1982-01-01

230

Absolute absorption spectra of batho- and photorhodopsins at room temperature. Picosecond laser photolysis of rhodopsin in polyacrylamide  

SciTech Connect

Picosecond laser photolysis of rhodopsin in 15% polyacrylamide gel was performed for estimating absolute absorption spectra of the primary intermediates of cattle rhodopsin (bathorhodopsin and photorhodopsin). Using a rhodopsin digitonin extract embedded in 15% polyacrylamide gel, a precise percentage of bleaching of rhodopsin after excitation of a picosecond laser pulse was measured. Using this value, the absolute absorption spectrum of bathorhodopsin was calculated from the spectral change before and 1 ns after the picosecond laser excitation (corresponding to the difference spectrum between rhodopsin and bathorhodopsin). The absorption spectrum of bathorhodopsin thus obtained displayed a lambda max at 535 nm, which was shorter than that at low temperature (543 nm) and a half band-width broader than that measured at low temperature. The oscillator strength of bathorhodopsin at room temperature was smaller than that at low temperature. The absolute absorption spectrum of photorhodopsin was also estimated from the difference spectrum measured at 15 ps after the excitation of rhodopsin, assuming a sequential conversion of photorhodopsin to bathorhodopsin. Its lambda max was located at approximately 570 nm, and the oscillator strength was smaller than those of rhodopsin and bathorhodopsin.

Kandori, H.; Shichida, Y.; Yoshizawa, T. (Kyoto Univ. (Japan))

1989-09-01

231

Isolation and identification of a polyacrylamide-degrading fungus and its degradation characteristics  

Microsoft Academic Search

A polyacrylamide-degrading fungus was selected from the soil in the chemical plant producting polyacrylamide, and it was named PAMF4. It is capable of utilizing polyacrylamide as sole nitrogen source. According to the morphological characteristics and 18S rRNA sequence analysis, the strain was preliminarily identified as Geotrichum candidum. As the indices with PAMF4 growth and polyacrylamide degradation rate, it was studied

Shu-qin Li; Lei Wang; Hong-xin Jin; Jing-gang Xu

2011-01-01

232

THE EFFECT OF HYDROPHILIC POLYACRYLAMIDE GELS ON ESTABLISHMENT OF WOODY PLANTS UNDER DROUGHTED AND SALINE CONDITIONS  

Microsoft Academic Search

The effect of hydrophilic polymers on newly planted trees and shrubs is one of the most confused areas of establishment research, with many papers reporting benefits where others show no effect or even suggest that the polymers may be harmful. Trials were carried out to try to identify the potential causes of such variation. To minimise genetic variation two cultivars

M. Winkelmann; A. D. Kendle

1996-01-01

233

Protein binding of procyanidins: studies using polyacrylamide gel electrophoresis and French maritime pine bark extract.  

PubMed

The application of PAGE to determine the interaction between procyanidins and proteins, as presented here, enables one to directly determine the binding of either a pure of a complex mixture of flavonoids to a particular protein. If the protein of interest is an enzyme, the combination of PAGE with quantitative activity measurements allows identifying whether a change in the enzyme activity is related to the binding. Data presented suggest that PBE and EGb 761 have protein-binding properties, which, in addition to their redox-based effects, could provide a biochemical basis for their action in biological systems. PMID:11400382

Moini, H; Guo, Q; Packer, L

2001-01-01

234

Murine T-cell response to native and recombinant protein antigens of Rickettsia tsutsugamushi.  

PubMed Central

A polyclonal T-cell line with TH1 characteristics was used to assess the murine cellular immune response to native and recombinant Rickettsia tsutsugamushi antigens. Proliferation of this T-cell line was observed in response to numerous native antigen fractions, which indicates that the murine T-helper-cell response is directed at multiple scrub typhus antigens with no apparent antigenic immunodominance. Subsequent analysis of recombinant R. tsutsugamushi antigens made it possible to identify a 47-kDa scrub typhus antigen (Sta47) that was stimulatory for the polyclonal T-cell line. Recombinant clones encoding 56-, 58-, and 110-kDa antigens (Sta56, Sta58, and Sta110, respectively) were unable to induce proliferation of this T-cell line. DNA sequence analysis of the cloned rickettsial insert encoding the Sta47 protein revealed the presence of four open reading frames potentially encoding proteins of 47, 30, 18, and 13 kDa. Analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis-separated and eluted fractions of lysates from the recombinant HB101(pRTS47B4.3) demonstrated that the fractions containing the 47-kDa protein as well as those containing proteins less than 18 kDa were stimulatory. Selected synthetic amphipathic peptides derived from the Sta47 antigen sequence identified a 20-amino-acid peptide that gave a 10-fold increase in T-cell proliferation over a control malarial peptide of similar length. Recognition of the 47-kDa antigen by a T-cell line with TH1 characteristics implicates this protein as one of potential importance in protection studies and future vaccine development. Images

Hickman, C J; Stover, C K; Joseph, S W; Oaks, E V

1993-01-01

235

Immobilization of enzymes on alginic acid-polyacrylamide copolymers  

SciTech Connect

In this report, the authors present initial results and limitations of a polymeric system for the immobilization of enzymes. Enzymes attached to insoluble polymers of natural and synthetic origin are gaining importance in many industrial and biomedical applications. Graft copolymers are used as enzyme supports and in this study a novel polymeric system of alginic acid-polyacrylamide graft copolymer is described which was used for immobilizing enzymes. (Refs. 4).

Kumaraswamy, M.D.K.; Panduranga R.K.; Thomas J.K.; Santappa, M.

1981-08-01

236

Viscoelasticity of Xanthan and Hydrolytic Polyacrylamide Mixed Aqueous Solutions  

Microsoft Academic Search

The viscoelasticity of Xanthan (XC) and hydrolytic polyacrylamide (HPAM) mixture in aqueous solution was studied. The effects of mixing proportion of the two polymers on its viscoelastic properties was determined, as well as its heat and salinity tolerance abilities. It is shown that, when the mixing proportion is 1:5 (XC\\/HPAM), the steady-shear viscosity of the mixture is higher than that

Yiming Li; Guiying Xu; Li Liu; Houjian Gong

2010-01-01

237

Type VI collagen of the intervertebral disc. Biochemical and electron-microscopic characterization of the native protein.  

PubMed Central

The collagen framework of the intervertebral disc contains two major fibril-forming collagens, types I and II. Smaller amounts of other types of collagen are also present. On examination of the nature and distribution of these minor collagens within bovine disc tissue, type VI collagen was found to be unusually abundant. It accounted for about 20% of the total collagen in calf nucleus pulposus, and about 5% in the annulus fibrosus. It was discovered by serially digesting disc tissue with chondroitin ABC lyase and Streptomyces hyaluronidase that native covalent polymers of type VI collagen could be extracted. Electron micrographs of this material prepared by rotary shadowing revealed the characteristic dimensions of tetramers and double tetramers of type VI molecules, with their central rods and terminal globular domains. Molecular-sieve column chromatography on agarose under non-reducing non-denaturing conditions gave a series of protein peaks with molecular sizes equivalent to the tetramer, double tetramer and higher multimers. On SDS/polyacrylamide-gel electrophoresis after disulphide cleavage, these fractions of type VI collagen all showed a main band at Mr 140,000 and four lesser bands between Mr 180,000 and 240,000. On electrophoresis without disulphide cleavage in agarose/2.4% polyacrylamide only dimeric (six chains) and tetrameric (12 chains) forms of type VI molecules were present. The ability to extract all the type VI collagen of the tissue in 4 M-guanidinium chloride, and absence of aldehyde-mediated cross-linking residues on direct analysis, showed that, in contrast with most matrix collagens, type VI collagen does not function as a covalently cross-linked structural polymer. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6.

Wu, J J; Eyre, D R; Slayter, H S

1987-01-01

238

Purification and characterization of keratin hydrolase in psoriatic epidermis: application of keratin-agarose plate and keratin-polyacrylamide enzymography methods.  

PubMed

Keratin-agarose plate and keratin-polyacrylamide enzymography methods were developed to demonstrate proteolytic digestion of epidermal keratin. By applying these methods, keratin hydrolase was purified from Tris-buffered saline extract of psoriatic scales by 50% ammonium sulfate precipitation, passage through a lysine-Sepharose column, DEAE-Sepharose, Sephacryl S-200, high-performance cation-exchange chromatography on Mono S, and aprotinin-Sepharose affinity chromatography. The final preparation demonstrated a single protein band at molecular weight 30,000 judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Furthermore, in keratin-polyacrylamide slab gels, the purified enzyme preparation showed a translucent band at molecular weight 30,000, indicating keratin digestion. Keratin hydrolase digested reassembled epidermal keratin as well, whereas it had no effect on guinea pig hair keratin. The enzyme demonstrated a high level of hydrolytic activity on Ile-Pro-Arg-p-nitroanilide and other peptidyl arginine substrates, while it showed a low level of activity on Val-Leu-Lys-p-nitroanilide, and no activity on Arg-Pro-Tyr-p-nitroanilide, Glu-Pro-Val-p-nitroanilide, or Ala-Ala-Ala-p-nitroanilide. The keratin hydrolase was a serine proteinase, inactivated by diisopropylfluorophosphate, phenylmethylsulfonyl fluoride, tosyl-lysyl-chloromethyl ketone, antipain, leupeptin, soybean trypsin inhibitor, aprotinin, and p-aminobenzamidine. The keratinolytic activity was not detected in normal epidermal extract. PMID:2409839

Hibino, T

1985-06-01

239

Process ceramic fibers by Sol-Gel  

Microsoft Academic Search

The Sol-Gel process may transform the materials of construction chemical engineers make and use--thin films, fibers, and powders. The advantage of the Sol-Gel technology is the ability to produce high purity products at low temperatures. For example, silica film is used to passivate integrated circuits. To achieve this, the native silicon substrate now is oxidized at about 1,000C for a

M. E. P. Fernandez de; Cheolho Kang; P. L. Mangonon

1993-01-01

240

2D gel proteomics: an approach to study age-related differences in protein abundance or isoform complexity in biological samples.  

PubMed

This chapter describes protocols for two-dimensional (2D) gel electrophoresis (isoelectric focusing [IEF] followed by sodium-dodecyl sulfate (SDS)-polyacrylamide gel electro-phoresis [PAGE]), staining of gels with the fluorescent dye Sypro Ruby, 2D gel image analysis, peptide mass fingerprint (PMF) analysis using matrix-assisted laser desorption ionization (MALDI)-time-of-flight (TOF) mass spectrometry (MS), liquid chromatography (LC)-tandem mass spectrometry (MS/MS), Western blot analysis of protein oxidations, and mass spectrometric mapping of sites of protein oxidations. Many of these methods were used to identify proteins affected in rat brain following ingestion of grape seed extract (GSE), a dietary supplement touted for anti-oxidant activity. Although beneficial actions in cell and animal models of chronic disease have been described for GSE, it has not been shown whether specific proteins were affected, or the nature of the effects. Applying 2D gel proteomics technology allowed discovery of proteins targeted by GSE without a priori knowledge of which one(s) might be affected. The newer 2D blue native (BN) electrophoresis methodology, which resolves protein complexes in a nondenaturing first dimension and then the components of these complexes in a denaturing second dimension, is discussed as a complementary approach. Analysis of protein oxidations and protein-protein interactions have special relevance to aging-related research, since oxidative stress and altered protein interactions may be at the heart of aging-related diseases. Finally, quality control issues related to implementation of high throughput technologies are addressed, to underscore the importance of minimizing bias and randomizing human and technical error in generating large datasets that are expensive and time-consuming to repeat. PMID:17634592

Kim, Helen; Eliuk, Shannon; Deshane, Jessy; Meleth, Sreelatha; Sanderson, Todd; Pinner, Anita; Robinson, Gloria; Wilson, Landon; Kirk, Marion; Barnes, Stephen

2007-01-01

241

Native American Stereotypes  

NSDL National Science Digital Library

You have been asked to write an opinion paper on the topic of naming sports teams' mascots after Native Americans. Use the following websites to find information to support your opinions. Why Dont Native Americans Like Sports Teams With Indian Mascots? Sports, Mascots, and Native Americans Native American Mascots: Racial Slur or Cherished Tradition To see another perspective on this topic, read the book Who Will Tell My Brother by Marlene Carvell. ...

Bates, Albion M.

2007-03-20

242

Alaska Natives & the Land.  

ERIC Educational Resources Information Center

Pursuant to the Native land claims within Alaska, this compilation of background data and interpretive materials relevant to a fair resolution of the Alaska Native problem seeks to record data and information on the Native peoples; the land and resources of Alaska and their uses by the people in the past and present; land ownership; and future…

Arnold, Robert D.; And Others

243

Sequencing of N-Linked Oligosaccharides Directly from Protein Gels: In-Gel Deglycosylation Followed by Matrix-Assisted Laser Desorption\\/Ionization Mass Spectrometry and Normal-Phase High-Performance Liquid Chromatography  

Microsoft Academic Search

A generally applicable, rapid, and sensitive method for profiling and sequencing of glycoprotein-associated N-linked oligosaccharides from protein gels was developed. The method employed sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) for protein separation and purification and in-gel deglycosylation using PNGase F for glycan release. Profiles of the neutral glycans from bovine ribonuclease B, chicken ovalbumin, and human immunoglobulin G (IgG), as

Bernhard Küster; Susan F. Wheeler; Ann P. Hunter; Raymond A. Dwek; David J. Harvey

1997-01-01

244

Zeta Potential Measurements of Glyoxalated Polyacrylamide (GPAM) Resins  

NASA Astrophysics Data System (ADS)

We will describe the use of a NICOMP 380 ZLS light scattering instrument (Particle Sizing Systems) to measure the zeta potential of glyoxalated polyacrylamide (GPAM) resins used in the paper industry. These experiments are part of a broader study of GPAM molecule properties (molecular weight, RMS radius, contour and persistence length) intended to understand differences in performance between various GPAM resins (specifically, differences in drainage performance during paper processing and wet/dry strength of paper). Additionally, zeta potential measurements help to understand the long term stability of these resins. Data and results obtained from the experiment will be presented.

Libi, Sumit; Shrestha, Apsana; Norwood, David; Boone, Steven

2013-03-01

245

Gel Electrophoresis  

NSDL National Science Digital Library

In this activity, learners simulate the process of DNA fingerprinting by using electricity to separate colored dyes. Learners use simple materials to assemble a comb (electrophoresis chamber) to hold the samples, make a 0.2% sodium bicarbonate buffer and 1% gel solution, connect a high voltage power supply, and prepare 5 different samples. Then learners test their model and observe each sample.

Yu, Julie

2007-01-01

246

Multifunctional Biodegradable Polyacrylamide Nanocarriers for Cancer Theranostics - A "See and Treat" Strategy  

PubMed Central

We describe here the development of multifunctional nanocarriers, based on amine functionalized biodegradable polyacrylamide nanoparticles (NPs), for cancer theranostics, including active tumor targeting, fluorescence imaging and photodynamic therapy. The structural design involves adding primary amino groups and biodegradable crosslinkers during the NP polymerization, while incorporating photodynamic and fluorescent imaging agents into the NP matrix, and conjugating PEG and tumor-targeting ligands onto the surface of the NPs. The as-synthesized NPs are spherical, with an average diameter of 44 nm. An accelerated biodegradation study, using sodium hydroxide or porcine liver esterase, indicated a hydrogel polymer matrix chain collapse within several days. By using gel permeation chromatography, small molecules were detected, after the degradation. In vitro targeting studies on human breast cancer cells indicate that the targeted NPs can be transported efficiently into tumor cells. Incubating the multifunctional nanocarriers into cancer cells enabled strong fluorescence imaging. Irradiation of the photosensitizing drug, incorporated within the NPs, with light of a suitable wavelength, causes significant but selective damage to the impregnated tumor cells, but only inside the illuminated areas. Overall, the potential of polymeric-based NPs as biodegradable, multifunctional nanocarriers, for cancer theranostics, is demonstrated here.

Wang, Shouyan; Kim, Gwangseong; Lee, Yong-Eun Koo; Hah, Hoe Jin; Ethirajan, Manivannan; Pandey, Ravindra K.; Kopelman, Raoul

2012-01-01

247

Multifunctional biodegradable polyacrylamide nanocarriers for cancer theranostics--a "see and treat" strategy.  

PubMed

We describe here the development of multifunctional nanocarriers, based on amine-functionalized biodegradable polyacrylamide nanoparticles (NPs), for cancer theranostics, including active tumor targeting, fluorescence imaging, and photodynamic therapy. The structural design involves adding primary amino groups and biodegradable cross-linkers during the NP polymerization, while incorporating photodynamic and fluorescent imaging agents into the NP matrix, and conjugating PEG and tumor-targeting ligands onto the surface of the NPs. The as-synthesized NPs are spherical, with an average diameter of 44 nm. An accelerated biodegradation study, using sodium hydroxide or porcine liver esterase, indicated a hydrogel polymer matrix chain collapse within several days. By using gel permeation chromatography, small molecules were detected, after the degradation. In vitro targeting studies on human breast cancer cells indicate that the targeted NPs can be transported efficiently into tumor cells. Incubating the multifunctional nanocarriers into cancer cells enabled strong fluorescence imaging. Irradiation of the photosensitizing drug, incorporated within the NPs, with light of a suitable wavelength, causes significant but selective damage to the impregnated tumor cells, but only inside the illuminated areas. Overall, the potential of polymeric-based NPs as biodegradable, multifunctional nanocarriers, for cancer theranostics, is demonstrated here. PMID:22702416

Wang, Shouyan; Kim, Gwangseong; Lee, Yong-Eun Koo; Hah, Hoe Jin; Ethirajan, Manivannan; Pandey, Ravindra K; Kopelman, Raoul

2012-08-28

248

Characterization of fish acid proteases by substrate-gel electrophoresis  

Microsoft Academic Search

Several analytical techniques based upon the use of substrate-polyacrylamide gel electrophoresis were evaluated to achieve characterization of aspartate proteases in fish stomach. Since aspartate proteases of fish are more stable at high pH than mammalian pepsins, the most accurate technique for activity assessment is electrophoresis at neutral pH and revealing of such activity at low pH with hemoglobin as substrate.

Manuel Diaz-Lopez; Francisco J. Moyano-Lopez; F. Javier Alarcon-Lopez; Fernando L. Garcia-Carreno; M. Angeles; Navarrete del Toro

249

Dielectric properties of gel collected from shark electrosensors  

NASA Astrophysics Data System (ADS)

To investigate the physical mechanism of the electric sense, we present an initial characterization of the dielectric properties of the glycoprotein gel that fills the electrosensitive organs of marine elasmobranches (sharks, skates, and rays). To ascertain the properties of the gel, low-frequency impedance spectroscopy is used. The impedance data collected from a dialyzed sample show large values of static permittivity and a loss peak corresponding to a long relaxation time (about 1 ms). Impedance measurements of the native (nondialyzed) gel reliable to 0.1 Hz will be presented and compared to the dialyzed gel. Ramifications of the gel's dielectric properties for the electric sense will be explored.

Hughes, Mary E.; Brown, Brandon R.; Hutchison, John C.; Murray, Royce W.

2003-03-01

250

Aerosol gels  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

251

Gradient gel electrophoretic separation of LDL and HDL subclasses on BioRad Mini Protean II and size phenotyping in healthy Macedonians  

Microsoft Academic Search

Background: Lipoprotein subclass determinations provide a more detailed reflection of lipoprotein metabolism and an accurate prediction for risk of cardiovascular disease. Gradient gel electrophoresis for lipoprotein separation on Pharmacia electrophoretic apparatus has been most commonly used for many years. Methods: In this paper, we describe a new method for separating LDL and HDL subclasses by nondenaturing polyacrylamide gradient (3–31%) gel

Sonja B Alabakovska; Bojana B Todorova; Danica D Labudovic; Katerina N Tosheska

2002-01-01

252

78 FR 70956 - 30-Day Notice of Proposed Information Collection: Assessment of Native American, Alaska Native...  

Federal Register 2010, 2011, 2012, 2013

...Information Collection: Assessment of Native American, Alaska Native and Native Hawaiian...Information Collection: Assessment of Native American, Alaska Native and Native Hawaiian...funding though several programs to Native American and Alaskan Native...

2013-11-27

253

Interfacing capillary gel microfluidic chips with infrared laser desorption mass spectrometry  

Microsoft Academic Search

We report on the fabrication and performance of a gel microfluidic chip interfaced to laser desorption\\/ionization (LDI) mass\\u000a spectrometry with a time-of-flight mass analyzer. The chip was fabricated from poly(methylmethacrylate) with a poly(dimethyl\\u000a siloxane) cover. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was performed in the channel of the microfluidic\\u000a chip. After electrophoresis, the cover was removed and either the PDMS chip

Yichuan Xu; Mark W. Little; Kermit K. Murray

2006-01-01

254

Detection of peptide nucleic acids in tissue extracts of treated animals by gel mobility shift assay  

Microsoft Academic Search

We have developed a sensitive and reproducible gel mobility shift assay to detect PNA oligomers in tissue of treated animals. PNA present in purified tissue extracts of treated animals is hybridized to a 33P-labelled DNA oligomer probe, and analyzed by polyacrylamide gel electrophoresis. The PNA–DNA hybrid migrates more slowly than the DNA probe alone and can be quantified relative to

Karen Jansen; Elliott Richelson

2000-01-01

255

Two-dimensional gel electrophoresis: recent advances in sample preparation, detection and quantitation  

Microsoft Academic Search

A strength of two-dimensional polyacrylamide gel electrophoresis (2D PAGE) is its ability to resolve and investigate the abundance of several thousand proteins in a single sample. This enables identification of the major proteins in a tissue or subcellular fraction by mass spectrometric methods. In addition, 2D PAGE can be used to compare quantities of proteins in related samples, such as

Kathryn S Lilley; Azam Razzaq; Paul Dupree

2002-01-01

256

Characterization of Carbohydrates Using Highly Fluorescent 2-Aminobenzoic Acid Tag Following Gel Electrophoresis of Glycoproteins  

Microsoft Academic Search

Application of the most sensitive fluorescent label 2-aminobenzoic acid (anthranilic acid, AA) for characterization of carbohydrates from the glycoproteins (?15 pmol) separated by polyacrylamide gel electrophoresis is described. AA label is used for the determination of both monosaccharide composition and oligosaccharide map. For the monosaccharide determination, bands containing the glycoprotein of interest are excised from the polyvinylidene fluoride (PVDF) membrane

Kalyan R. Anumula; Ping Du

1999-01-01

257

Measurement of normative HDL subfraction cholesterol levels by Gaussian summation analysis of gradient gels  

Microsoft Academic Search

This report describes development of a computerized method for analyzing polyacrylamide gradient gels of high den- sity lipoproteins (HDL) by Gaussian summation, a simple tech- nique to obtain standardized measurements of size and amount of HDL subfractions. Conditions for reproducibility and ranges of linearity were established. By Gaussian summation analysis, five or six HDL subfractions could be found in the

Roy B. Verdery; David F. Benham; Howard L. Baldwin; Andrew P. Goldberg; Alexander V. Nichols

258

Exploring Native Science  

NSDL National Science Digital Library

This article describes an innovative summer camp program that serves middle school I�upiat and Athabascan students from the interior and the arctic regions of Alaska. The camp enables students to learn from Native Elders while completing hands-on science projects; stimulates interest in and increasing students' confidence and knowledge in mathematics, science, and engineering among Alaska Native students; and provides a curriculum that integrates Alaska Native knowledge systems and values with western mathematics and science.

Engblom-Bradley, Claudette; Reyes, Mar�a E.

2004-04-01

259

Native American Powerpoint Project  

NSDL National Science Digital Library

For this project students will research a Native American group that played an influential role in Alabama history. The students will then create a powerpoint describing the primary aspects of that group's heritage. Directions: 1. Choose any one of the Native American tribes we have been learning about in class. 2. Visit the following sites to learn more about the tribe that you have chosen: 1) Access Geneology 2) Native Languages ...

Albright, Miss

2009-07-09

260

A novel polyacrylamide nanocomposite hydrogel reinforced with natural chitosan nanofibers.  

PubMed

Polyacrylamide (PAM) was used as a matrix material for fabricating novel nanocomposite hydrogels reinforced with natural chitosan nanofibers (CNFs) via in situ free-radical polymerization. The nanocomposite's structure, strength, morphology and rheological properties were investigated. The results showed that the CNFs had a strong interaction with PAM through hydrogen and covalent bondings. The CNFs acted as a multifunctional cross-linker and a reinforcing agent in the hydrogel system. The compression strength and storage modulus of the nanocomposite hydrogels were significantly higher than those of the pure PAM hydrogels and the corresponding PAM/chitosan semi-interpenetrating polymer network (PAM-SIPN) hydrogels. The swelling ratio (SR) of the nanocomposite hydrogels was lower than that of the PAM hydrogel, but was similar to that of the PAM-SIPN hydrogel. Among the CNF contents used, the 1.5 wt% CNF loading level showed the best combined swelling and mechanical properties for the hydrogels. PMID:21273050

Zhou, Chengjun; Wu, Qinglin

2011-05-01

261

Chemical degradation of polyacrylamide by advanced oxidation processes  

Microsoft Academic Search

This paper presents the results obtained from the oxidation of polyacrylamide (PAM) by the UV\\/H2O2, Fenton, UV\\/Fenton, visible light\\/Fenton, visible light\\/Fenton\\/C2O, UV\\/Fenton\\/C2O, visible light\\/Fenton\\/C4H4O and UV\\/Fenton\\/C4H4O processes. Degradation efficiency for PAM had the following order: UV\\/Fenton\\/C4H4OFenton\\/C2O visible light\\/Fenton\\/C4H4O visible light\\/Fenton\\/C2O UV\\/Fenton>visible light\\/Fenton>UV\\/H2O2>Fenton. The addition of tartrate had a positive effect on chemical oxygen demand (COD) removal. Increasing the concentrations of

Mang Lu; Xuejiao Wu; Xiaofang Wei

2012-01-01

262

Chemical degradation of polyacrylamide by advanced oxidation processes  

Microsoft Academic Search

This paper presents the results obtained from the oxidation of polyacrylamide (PAM) by the UV\\/H2O2, Fenton, UV\\/Fenton, visible light\\/Fenton, visible light\\/Fenton\\/C2O, UV\\/Fenton\\/C2O, visible light\\/Fenton\\/C4H4O and UV\\/Fenton\\/C4H4O processes. Degradation efficiency for PAM had the following order: UV\\/Fenton\\/C4H4OFenton\\/C2O visible light\\/Fenton\\/C4H4O visible light\\/Fenton\\/C2O UV\\/Fenton>visible light\\/Fenton>UV\\/H2O2>Fenton. The addition of tartrate had a positive effect on chemical oxygen demand (COD) removal. Increasing the concentrations of

Mang Lu; Xuejiao Wu; Xiaofang Wei

2011-01-01

263

Polyacrylamide based ICG nanocarriers for enhanced fluorescence and photoacoustic imaging  

NASA Astrophysics Data System (ADS)

Indocyanine green (ICG) is an FDA approved tricarbocyanine dye. This dye, with a strong absorbance in the near infrared (NIR) region, has been extensively used for fluorescence and photoacoustic imaging in vivo. ICG in its free form, however, has a few drawbacks that limit its in vivo applications, such as non-targetability, tendency to form aggregates which changes its optical properties, fast degradation, short plasma lifetime and reduced fluorescence at body temperature. In order to bypass these inherent drawbacks, we demonstrate a polyacrylamide based nanocarrier that was particularly designed to carry the negatively charged ICG molecules. These nanocarriers are biodegradable, biocompatible and can be specifically targeted to any cell or tissue. Using these nanocarriers we avoid all the problems associated with free ICG, such as degradation, aggregation and short plasma lifetime, and also enhance demonstrate its ability towards photoacoustics and fluorescence imaging.

Ray, Aniruddha; Yoon, Hyung Ki; Ryu, HeeJu; Koo Lee, Yong-Eun; Kim, Gwangseong; Wang, Xueding; Kopelman, Raoul

2013-02-01

264

Detection of fluorescence dye-labeled proteins in 2-D gels using an Arthur 1442 Multiwavelength Fluoroimager.  

PubMed

Labeling of proteins with SYPRO Orange, SYPRO Red, and SYPRO Ruby after 2-D polyacrylamide gel electrophoresis (PAGE) using plastic-backed immobilized pH gradient (IPG) strips and precast SDS polyacrylamide gels was tested. Protein spots were detected using an Arthur 1442 Multiwavelength Fluoroimager. The labeling methods described allow detection of proteins both after isoelectric focusing (IEF) and PAGE with a sensitivity higher than or comparable to standard silver staining methods. In addition to the post-labeling methods mentioned above, pre-labeling with the cysteine-specific fluorophore monobromobimane before 2-D PAGE is a sensitive, fast, and cost-effective alternative to existing staining protocols. PMID:11464508

Herick, K; Jackson, P; Wersch, G; Burkovski, A

2001-07-01

265

Poisson's ratio in polymer gels near the phase-transition point  

NASA Astrophysics Data System (ADS)

Poisson's ratio, which was obtained by measuring swelling curves of free and radially constrained gels, has been investigated as a function of temperature and ionic strength for N-isopropylacrylamide (NIPA) gels and as a function of acetone concentration for polyacrylamide gels. It was found that the Poisson ratio exhibits a negative dip near the transition temperature for both neutral and ionic NIPA gels. The dip becomes deeper and shifts to a higher temperature as the ionic strength increases. The negative Poisson ratio of NIPA gels suggests that the bulk modulus is much smaller than the shear modulus as gels undergo the phase transition. The Poisson ratio of acrylamide gel, however, was found to be positive throughout the measured region.

Li, Chunfang; Hu, Zhibing; Li, Yong

1993-07-01

266

Identification of species of fish by gradient-gel electrophoresis.  

PubMed

An electrophoretic method is described for distinguishing between fish fillets according to their protein composition. Thaw fluid (4 microL) was applied to one of 14 sample positions of a precast gel, containing a gradient of polyacrylamide of either 2.5 to 27% or 3 to 40%. All reagents and gels are commercially available in ready-to-use form. Either gel provided a distinction between any of the 42 fish types, but the 3 to 40% gel gave better identification because of its superior molecular-sieving properties. Reproducible electrophoretic patterns were obtained for different samples of the same fish type, but small differences were shown for fish of widely different origin, for example Australian and New Zealand ling. PMID:3834902

Manusu, H P; Wrigley, C W

1985-11-01

267

Spot volume vs. amount of protein loaded onto a gel: a detailed, statistical comparison of two gel electrophoresis systems.  

PubMed

The long-term goal of this research program is to clarify the molecular mechanisms that participate in the formation of human pituitary macroadenomas. One approach to that goal is to characterize the differentially expressed proteins that are found by a comparison of the proteomes of control pituitary vs. macroadenoma tissues. In order to accurately perform a comparative proteomics study, based on the combination of two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and PDQuest 2-D analysis software, a reproducible 2-DE separation system with a wide linear dynamic measure range is needed. A typical horizontal system is the Multiphor II system that analyzes one gel at a time, using a precast gradient gel (180 x 245 x 0.5 mm); a typical vertical system is the Dodeca system that analyzes up to 12 gels at a time on a single-concentration gel (190 x 205 x 1.0 mm). We have evaluated (Zhan and Desiderio, Electrophoresis 2003, 24, 1834-1846) the spatial and quantitative reproducibility of the two second-dimensional gel systems to separate a human pituitary proteome; that study showed a higher reproducibility for the Dodeca gel system. This present study investigated the relationship between the spot volume and the amount of protein loaded onto the gel for those two 2-D systems. The results demonstrated that the Dodeca gel system provides a wider linear dynamic range to measure the changes in the protein abundance in pituitary proteome. PMID:12783459

Zhan, Xianquan; Desiderio, Dominic M

2003-06-01

268

Legends of Native Americans.  

ERIC Educational Resources Information Center

Presents a theme unit that includes elementary-level, cross-curricular lessons about lifestyle, belief systems, traditions, and history of Native Americans. The unit includes a poster which offers a traditional Cherokee story, literature on Native American legends, and a variety of cross-curricular activities. The unit ends with students writing…

Flagg, Ann

1999-01-01

269

Historic Native Americans  

NSDL National Science Digital Library

What are the four historic Native American tribes and what are different things involved in their culture? Teacher will give you sheet and as you discover new facts about each historic Native American tribe, write down the type of food they ate and another fact about them on this sheet. Graphic First let's learn some background information ...

G, Miss

2011-10-27

270

Chemical and photolytic degradation of polyacrylamides used in potable water treatment  

Microsoft Academic Search

Polyacrylamides (PAMs) are a class of polymers formed from acrylamide alone or copolymerized with other monomers. PAMs have been used in drinking water treatment as flocculants or coagulants in the highest volume among all the polymer types. In potable water treatment processes, polyacrylamides are often exposed to oxidants (e.g. chlorine and permanganate) and UV irradiation from sunlight or artificial sources.

Peiyao Cheng

2004-01-01

271

Protein Profile in Corpus Luteum during Pregnancy in Korean Native Cows  

PubMed Central

Steroidogenesis requires coordination of the anabolic and catabolic pathways of lipid metabolism, but the profile of proteins associated with progesterone synthesis in cyclic and pregnant corpus luteum (CL) is not well-known in cattle. In Experiment 1, plasma progesterone level was monitored in cyclic cows (n = 5) and pregnant cows (n = 6; until d-90). A significant decline in the plasma progesterone level occurred at d-19 of cyclic cows. Progesterone level in abbatoir-derived luteal tissues was also determined at d 1 to 5, 6 to 13 and 14 to 20 of cyclic cows, and d-60 and -90 of pregnant cows (n = 5 each). Progesterone level in d-60 CL was not different from those in d 6 to 13 CL and d-90 CL, although the difference between d 6 to 13 and d-90 was significant. In Experiment 2, protein expression pattern in CL at d-90 (n = 4) was compared with that in CL of cyclic cows at d 6 to 13 (n = 5). Significant changes in the level of protein expression were detected in 32 protein spots by two-dimensional polyacrylamide gel electrophoresis (2-DE), and 23 of them were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Six proteins were found only in pregnant CL, while the other 17 proteins were found only in cyclic CL. Among the above 6 proteins, vimentin which is involved in the regulation of post-implantation development was included. Thus, the protein expression pattern in CL was disorientated from cyclic luteal phase to mid pregnancy, and alterations in specific CL protein expression may contribute to the maintenance of pregnancy in Korean native cows.

Chung, H. J.; Kim, K. W.; Han, D. W.; Lee, H. C.; Yang, B. C.; Chung, H. K.; Shim, M. R.; Choi, M. S.; Jo, E. B.; Jo, Y. M.; Oh, M. Y.; Jo, S. J.; Hong, S. K.; Park, J. K.; Chang, W. K.

2012-01-01

272

Regioselective immobilization of short oligonucleotides to acrylic copolymer gels.  

PubMed Central

Four types of polyacrylamide or polydimethyl-acrylamide gels for regioselective (by immobilization at the 3' end) of short oligonucleotides have been designed for use in manufacturing oligonucleotide microchips. Two of these supports contain amino or aldehyde groups in the gel, allowing coupling with oligonucleotides bearing aldehyde or amino groups, respectively, in the presence of a reducing agent. The aldehyde gel support showed a higher immobilization efficiency relative to the amino gel. Of all reducing agents tested, the best results were obtained with a pyridine-borane complex. The other supports are based on an acrylamide gel activated with glutaraldehyde or a hydroxyalkyl-functionalized gel treated with mesyl chloride. The use of dimethylacrylamide instead of acrylamide allows subsequent gel modifications in organic solvents. All the immobilization methods are easy and simple to perform, give high and reproducible yields, allow long durations of storage of the activated support, and provide high stability of attachment and low non-specific binding. Although these gel supports have been developed for preparing oligonucleotide microchips, they may be used for other purposes as well.

Timofeev, E; Kochetkova, S V; Mirzabekov, A D; Florentiev, V L

1996-01-01

273

Regioselective immobilization of short oligonucleotides to acrylic copolymer gels.  

PubMed

Four types of polyacrylamide or polydimethyl-acrylamide gels for regioselective (by immobilization at the 3' end) of short oligonucleotides have been designed for use in manufacturing oligonucleotide microchips. Two of these supports contain amino or aldehyde groups in the gel, allowing coupling with oligonucleotides bearing aldehyde or amino groups, respectively, in the presence of a reducing agent. The aldehyde gel support showed a higher immobilization efficiency relative to the amino gel. Of all reducing agents tested, the best results were obtained with a pyridine-borane complex. The other supports are based on an acrylamide gel activated with glutaraldehyde or a hydroxyalkyl-functionalized gel treated with mesyl chloride. The use of dimethylacrylamide instead of acrylamide allows subsequent gel modifications in organic solvents. All the immobilization methods are easy and simple to perform, give high and reproducible yields, allow long durations of storage of the activated support, and provide high stability of attachment and low non-specific binding. Although these gel supports have been developed for preparing oligonucleotide microchips, they may be used for other purposes as well. PMID:8774893

Timofeev, E; Kochetkova, S V; Mirzabekov, A D; Florentiev, V L

1996-08-15

274

In-gel technology for PCR genotyping and pathogen detection.  

PubMed

This work describes the use of polyacrylamide gel and PCR reagents photopolymerized in a mold to create an array of semisolid posts that serve as reaction vessels for parallel PCR amplification of an externally added template. DNA amplification occurred in a cylindrical, self-standing 9 × 9 array of gel posts each less than 1 ?L in volume. Photopolymerization of the gel with an intercalating dye added prior to polymerization permitted acquisition of real-time PCR data and melting curve analysis data without the need for any type of post-PCR staining procedures. PCR was equally efficient and reproducible when template DNA was polymerized within the gel or when exogenous template was added atop precast gel posts. PCR amplification occurred with template from purified DNA or from raw urine of patients with BK viruria. Multiple primer sets can be utilized per gel post array with no detectable cross contamination. As few as 34 BK virus templates were consistently detected by PCR in an individual gel post. Amplification of HPA1 and FGFR2 genes in human genomic DNA (gDNA) required as little as 2-5 ng of gDNA template/gel post. The device prototype includes a Peltier element for PCR thermal cycling and a CCD camera to capture fluorescence for product detection. Our technology is amenable to integration in point of care microdevices. PMID:20809605

Atrazhev, Alexey; Manage, Dammika P; Stickel, Alexander J; Crabtree, H John; Pilarski, Linda M; Acker, Jason P

2010-10-01

275

Electrophoretic extraction of proteins from two-dimensional electrophoresis gel spots  

DOEpatents

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

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

1987-09-04

276

Native American Times  

NSDL National Science Digital Library

The Native American Times makes good on its promise to deliver "today's independent Indian news." The site has a clean design that includes ten sections covering topics like business, culture, education, sports, and powwows. The News area offers a nice digest of what's going on in several areas of interest to Native Americans, with topical headlines that include "Cherokee Art Market Announces Winners" and "Yakama Maintain Wild Horse Race Tradition." The site also includes a great jobs area for folks who might be looking for Native American-focused work in public policy, community development, technology, and other fields.

277

Antimicrobial activity of silver/starch/polyacrylamide nanocomposite.  

PubMed

A novel silver/starch/polyacrylamide nanocomposite hydrogel was prepared by grafting acrylamide onto starch in presence of silver nitrate by use of ammonium persulphate as an initiator and N,N-methylene-bisacrylamide as a crosslinking agent, then reducing the silver ions enclosed in the hydrogel structure to silver nanoparticles by treating the hydrogel with sodium hydroxide solution. All factors which affect the grafting/crosslinking reaction were optimized and the concentration of silver ion was changed from 0ppm to 50ppm. The produced nanocomposite hydrogel was characterized for its nanosilver content and the UV-spectra showed similar absorption spectra at wavelength 405nm for all AgNO3 concentrations but the plasmon showed increase in the intensity of the absorption peak as AgNO3 concentration incorporated to the hydrogel structure increases. The nanocomposite hydrogel was also characterized for its antimicrobial activity toward two types of bacteria and two types of fungi. The results showed that the hydrogel with 0ppm silver content has no antimicrobial activity, and that the antimicrobial activity expressed as inhibition zone increases as the silver content increases from 5ppm to 50ppm. PMID:24769214

Abdel-Halim, E S; Al-Deyab, Salem S

2014-07-01

278

Polyacrylamide hydrogel injection for breast augmentation: Another injectable failure  

PubMed Central

Summary Background Increasing complications of polyacrylamide hydrogel (PAAG) augmentation mammoplasty, such as chronic persistent infection, have recently caught the attention of both the medical field and the general public. Material/Methods A total of 96 patients with severe chronic infection following PAAG augmentation mammoplasty were treated in the present study including 63 cases with infection confined to the breast and 33 with systemic infection. Endoscopy and surgery were performed to completely remove the materials and clear the infected tissues followed by drug-irrigation and vacuum-assisted closure for several days. Results In patients with severe infection there were large amounts of PAAG, fibers and infiltration of numerous neutrophils and macrophages. The infection-inducing materials were extensively dispersed in the mammary and subcutaneous tissues, pectoral fascia and intermuscular space. In addition, there was scattered distribution of PAAG materials in the armpit, chest wall and abdominal wall, which were mixed with necrotic tissues and surrounded by lymphocytes, giant cells, macrophages and other inflammatory cells, forming chronic granulomatous and fibrous lesions. Infection was controlled following surgical intervention. No residual infectious foci or recurrent infections were noted among these patients. Although the severe infection did not result in mastectomy, patients had breast atrophy and various degrees of deformation. Conclusions Chronic infection following PAAG augmentation mammaplasty usually causes systemic infection and other devastating adverse reactions. This study confirms PAAG augmentation mammaplasty is another failed attempt. More attention should be paid to the injection of large doses of liquid filler.

Wang, Zhenxiang; Li, Shirong; Wang, Lingli; Zhang, Shu; Jiang, Yan; Chen, Jinping; Luo, Donglin

2012-01-01

279

Encapsulation efficiency and controlled release characteristics of crosslinked polyacrylamide particles.  

PubMed

Polyacrylamide (pAAm) particles crosslinked with N,N-methylenebis-acrylamide/ethylene glycol dimethacrylate (NNMBA/EGDMA) have been prepared in water-methanol medium by the dispersion polymerization using poly(vinyl pyrrolidone), PVP as a steric stabilizer. 5-fluorouracil an anticancer drug, has been loaded in situ into the crosslinked pAAm particles. Plain as well as drug loaded microparticles have been characterized by differential scanning calorimetry (DSC) and X-ray diffraction studies (XRD) and scanning electron microscopy (SEM). DSC and XRD studies have indicated a molecular level dispersion of the drug in pAAm particles during in situ loading and SEM pictures have shown the formation of spherical and oval-shaped particles. In vitro release of 5-fluorouracil from the crosslinked pAAm particles has been carried out in 7.4 pH buffer medium. Both encapsulation efficiency and release patterns are found to depend on the nature of the crosslinking agent, amount of crosslinking agent used and the amount of drug loaded. In vitro release studies indicated the controlled release of 5-fluorouracil up to 12 h. PMID:16766148

Sairam, Malladi; Babu, V Ramesh; Vijaya, Boya; Naidu, Kumar; Aminabhavi, Tejraj M

2006-08-31

280

Native American Tribal Websites.  

ERIC Educational Resources Information Center

Lists Web sites maintained by 38 different Native American nations that deal with topics ranging from tribal history, news, arts and crafts, tourism, entertainment, and commerce. Represented nations include Apache, Blackfeet, Creek, Iroquois, Mohegan, and Sioux. (CMK)

Miller, Eric L.

1999-01-01

281

Alaska Native Science Commission  

NSDL National Science Digital Library

This is the homepage of the Alaska Native Science Commission (ANSC), an organization dedicated to bringing together research and science in partnership with the Native community. Site materials include information on Alaska Native communities; a searchable database of contacts for community knowledge and a directory of local, statewide, and federally recognized Alaska Native agencies. There is also information on organizational ethics and protocols, regulatory agencies, a browsable database of research projects, and information on sources of funding. The Key Issues page provides information on issues of concern, such as avian flu, climate change, observations about contaminants and environmental change, traditional knowledge systems, traditional foods, and views on climate change and ecology. For students, there is information on einternship and scholarship opportunities. The publications page provides access to archived newsletters, presentations, and reports.

2010-10-05

282

Molecular interactions in a surfactant-water-polyacrylamide system, according to densimetry, viscometry, conductometry, and spectroscopy data  

NASA Astrophysics Data System (ADS)

Molecular interactions in a surfactant-polyacrylamide-water system are investigated. It is established that the interactions affect such physicochemical parameters of the system as viscosity, density, surface tension, conductivity, and critical micelle concentration. It is shown that in a polyacrylamide-water system, raising the polyacrylamide concentration to 0.02% causes conformational changes in its macromolecule.

Harutyunyan, R. S.

2013-08-01

283

Probing structure-antifouling activity relationships of polyacrylamides and polyacrylates.  

PubMed

We have synthesized two different polyacrylamide polymers with amide groups (polySBAA and polyHEAA) and two corresponding polyacrylate polymers without amide groups (polySBMA and polyHEA), with particular attention to the evaluation of the effect of amide group on the hydration and antifouling ability of these systems using both computational and experimental approaches. The influence of polymer architectures of brushes, hydrogels, and nanogels, prepared by different polymerization methods, on antifouling performance is also studied. SPR and ELISA data reveal that all polymers exhibit excellent antifouling ability to repel proteins from undiluted human blood serum/plasma, and such antifouling ability can be further enhanced by presenting amide groups in polySBAA and polyHEAA as compared to polySBMA and polyHEA. The antifouling performance is positively correlated with the hydration properties. Simulations confirm that four polymers indeed have different hydration characteristics, while all presenting a strong hydration overall. Integration of amide group with pendant hydroxyl or sulfobetaine group in polymer backbones is found to increase their surface hydration of polymer chains and thus to improve their antifouling ability. Importantly, we present a proof-of-concept experiment to synthesize polySBAA nanogels, which show a switchable property between antifouling and pH-responsive functions driven by acid-base conditions, while still maintaining high stability in undiluted fetal bovine serum and minimal toxicity to cultured cells. This work provides important structural insights into how very subtle structural changes in polymers can yield great improvement in biological activity, specifically the inclusion of amide group in polymer backbone/sidechain enables to obtain antifouling materials with better performance for biomedical applications. PMID:23562049

Zhao, Chao; Zhao, Jun; Li, Xiaosi; Wu, Jiang; Chen, Shenfu; Chen, Qiang; Wang, Qiuming; Gong, Xiong; Li, Lingyan; Zheng, Jie

2013-07-01

284

Native Knowledge in the Americas.  

ERIC Educational Resources Information Center

Native American science is defined as activities of native peoples of the New World in observing physical phenomena and attempting to explain and control them. Problems in studying native science, ethnoscience and native science, archaeostronomy and ethnoastronomy, ethnobotany, agriculture, technology, and future directions are discussed. (JN)

Kidwell, Clara Sue

1985-01-01

285

Investigation of the properties of polyacrylamide-polyaniline composite and its application as a battery electrode  

SciTech Connect

The composite films of polyacrylamide and polyaniline were prepared by polymerizing aniline using ammonium persulfate as an initiator in an aqueous solution containing poly-acrylamide. A film was then cast from this solution. The structural, dynamic mechanical, electrical, and thermal properties of these films have been studied. The infrared spectrum shows the presence of polyacrylamide as well as polyaniline in the composite film. The thermal analysis shows that the composite degrades slower than does the polyacrylamide alone. The dynamic mechanical analysis indicates that there is an increase in the glass transition temperature after the composite formation. The electrical conductivity has been found to increase by more than eight orders of magnitude. These composite films have also been suitably used as electrodes in secondary batteries.

Bhat, N.V.; Joshi, N.V. (Univ. of Bombay, (India). Dept. of Chemical Technology)

1993-11-20

286

Iontophoresis of Salicylic Acid From Salicylic Acid Doped Poly(p-phynylene vinylene)\\/ Polyacrylamide Hydrogels  

Microsoft Academic Search

The apparent diffusion coefficients, Dapp, and the release mechanisms of salicylic acid from salicylic acid-loaded polyacrylamide hydrogels, SA-loaded PAAM, and salicylic acid-doped poly(phenylene vinylene)\\/polyacrylamide hydrogels, SA-doped PPV\\/PAAM, were investigated. In the absence of an electric field, the diffusion of SA from the SA-doped PPV\\/PAAM hydrogel is delayed in the first 3 hr due to the ionic interaction between the anionic

Sumonman Niamlang

2009-01-01

287

Chemical gel barriers as low-cost alternative to containment and in situ cleanup of hazardous wastes to protect groundwater  

SciTech Connect

Chemical gel barriers are being considered as a low-cost alternative for containment and in situ cleanup of hazardous wastes to protect groundwater. Most of the available gels in petroleum application are non-reactive and relative impermeable, providing a physical barriers for all fluids and contaminants. However, other potential systems can be envisioned. These systems could include gels that are chemically reactive and impermeable such that most phase are captured by the barriers but the contaminants could diffuse through the barriers. Another system that is chemically reactive and permeable could have potential applications in selectivity capturing contaminants while allowing water to pass through the barriers. This study focused on chemically reactive and permeable gel barriers. The gels used in experiment are DuPont LUDOX SM colloidal silica gel and Pfizer FLOPAAM 1330S hydrolyzed polyacrylamide (HPAM) gel.

NONE

1997-01-01

288

Plasmid topoisomer separation by capillary gel electrophoresis  

NASA Astrophysics Data System (ADS)

We report capillary electrophoretic separation of pUC8 and pBr322 plasmid topoisomers in cross-linked polyacrylamide (PAA) gels in 1X TBE buffer. Plasmid topoisomers are supercoiled forms that have exactly the same chain length but differ in their number of superhelical turns. Because the size in base pairs is invariant, topoisomer mobilities reflect conformational details and differ by only small increments. In cross-linked PAA rapid topoisomer separation can be achieved by DC electrophoresis in capillary lengths as short as 3 cm and near-baseline resolution in longer capillaries. We propose that the separation depends upon the regular structure obtained when a gel is prepared intra-capillary. The isothermal environment promotes formation of a cross-linked polymer of low polydispersity. Such PAA is a sieving matrix of high resolving power, but usable over a relatively narrow DNA size range. It is also possible to prepare gels in which a wide base pair range of supercoiled and nicked plasmids as well as linear ds-DNA may be separated, but without topoisomers resolution. In this paper, we discuss the latest results in topoisomer resolution using a range of plasmids employed in molecular biology and gene therapy.

de Carmejane, Olivia; Schwinefus, Jeffrey J.; Morris, Michael D.

1999-05-01

289

Purification of polyhydroxybutyrate synthase from its native organism, Ralstonia eutropha: implications for the initiation and elongation of polymer formation in vivo.  

PubMed

Class I polyhydroxybutyrate (PHB) synthase (PhaC) from Ralstonia eutropha catalyzes the formation of PHB from (R)-3-hydroxybutyryl-CoA, ultimately resulting in the formation of insoluble granules. Previous mechanistic studies of R. eutropha PhaC, purified from Escherichia coli (PhaC(Ec)), demonstrated that the polymer elongation rate is much faster than the initiation rate. In an effort to identify a factor(s) from the native organism that might prime the synthase and increase the rate of polymer initiation, an N-terminally Strep2-tagged phaC (Strep2-PhaC(Re)) was constructed and integrated into the R. eutropha genome in place of wild-type phaC. Strep2-PhaC(Re) was expressed and purified by affinity chromatography from R. eutropha grown in nutrient-rich TSB medium for 4 h (peak production PHB, 15% cell dry weight) and 24 h (PHB, 2% cell dry weight). Analysis of the purified PhaC by size exclusion chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and gel permeation chromatography revealed that it unexpectedly copurified with the phasin protein, PhaP1, and with soluble PHB (M(w) = 350 kDa) in a "high-molecular weight" (HMW) complex and in monomeric/dimeric (M/D) forms with no associated PhaP1 or PHB. Assays for monitoring the formation of PHB in the HMW complex showed no lag phase in CoA release, in contrast to M/D forms of PhaC(Re) (and PhaC(Ec)), suggesting that PhaC in the HMW fraction has been isolated in a PHB-primed form. The presence of primed and nonprimed PhaC suggests that the elongation rate for PHB formation is also faster than the initiation rate in vivo. A modified micelle model for granule genesis is proposed to accommodate the reported observations. PMID:22369488

Cho, Mimi; Brigham, Christopher J; Sinskey, Anthony J; Stubbe, JoAnne

2012-03-20

290

Solids and nutrient removal from flushed swine manure using polyacrylamides  

SciTech Connect

Most of the organic nutrients and reduced carbon (C) materials in liquid swine manure are contained in fine suspended particles that are not separated by available mechanical separators. Treatment with polyacrylamide (PAM) polymers prior to mechanical removal or gravity settling has the potential for enhancing solids-liquid separation, thus concentrating nitrogen (N), phosphorus (P), and organic C. In this work, the authors determined PAM charge and density characteristics most desirable for swine wastewater applications and established the optimum chemical requirement. Treatments were applied to flushed manure from two swine operations in North Carolina. Cationic PAMs significantly increased solids separation while performance of neutral and anionic types was not different from a control. Cationic PAMs with moderate-charge density (20%) were more effective than polymers with higher charge density. Flocs were large and effectively retained with a 1-mm screen. Optimum PAM rate varied with the amount of total suspended solids (TSS) in the liquid manure; 26 and 79 mg PAM/L for samples containing 1.5 and 4.1 g TSS/L, respectively. Corresponding TSS removal efficiencies were 90 to 94%. In contrast, screening without PAM treatment captured only 5 to 14% of the suspended solids. Polymer usage rate was consistent and averaged 2.0{degree} based on weight of dry solids produced. Volatile suspended solids (VSS) were highly correlated with TSS and comprised 79.5% of TSS. Chemical oxygen demand (COD) and organic nutrient concentrations in the effluent were also significantly decreased by PAM treatment. The decrease of COD concentration, an important consideration for odor control, was linearly related with removal of suspended solids, at a rate of 2.0 g COD/g TSS and 2.6 g COD/g VSS. Removal efficiency of organic N and P followed approximately a 1:1 relationship with removal efficiency of TSS. Chemical cost to capture 90% of the suspended solids was estimated to be $0.026 per hog per day ($2.79 per finished hog). Results obtained indicate that PAM treatment is very effective for removal of manure solids, COD, and organic nutrients from flushed swine effluents. The technology provides an attractive alternative to existing liquid manure handling methods for conserving nutrients and avoiding excessive nutrient application in areas where swine production is concentrated.

Vanotti, M.B.; Hunt, P.G.

1999-12-01

291

Native American Manuscript Collections  

NSDL National Science Digital Library

Based at the University of Oklahoma's Western History Collection, the Native American Manuscript Collections contain over 200 documents relating to Native Americans in Oklahoma, Indian Territory, and the southwestern United States. On the homepage, visitors can browse the manuscripts, which are listed by nation. The Creek Nation area is quite fascinating, as there are over 35 documents here including handwritten journals, trading company ledgers, and letters from farmers like James M. Latty and other Creeks. After this introduction, visitors can browse around through the works of other nations, including the Cherokee, Choctaw, and Chickasaw.

292

Analysis of protein changes using two-dimensional difference gel electrophoresis.  

PubMed

A protocol for protein analysis using two-dimensional difference gel electrophoresis (2D-DIGE) is described. 2D-DIGE is one of the most popular and versatile methods of protein separation among rapidly increasing proteomics technologies. Similar to traditional two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), the proteins are separated based on their charges and molecular weight by 2D-DIGE. Different from 2D-PAGE, proteins are pre-labeled with different fluorescent and different protein samples are run in one gel by this method. Therefore, 2D-DIGE not only carries the advantages of 2D-PAGE but also eliminates gel-to-gel variation and achieves high resolution, sensitivity, and reproducibility. PMID:24623216

Gao, Weimin

2014-01-01

293

Quantitation and characterization of rat tissue metallothioneins by gel electrophoresis  

SciTech Connect

A discontinuous gradient gel electrophoretic system was developed to quantitate and characterize metallothionein (MT) in rat tissue. Vertical slab separating gels (1.5 mm x 14 cm x 12 cm) consisted of a linear polyacrylamide gradient 7.5 to 30% T and 5% Bis. The stacking gels (3% T and 20% Bis) were photopolymerized using riboflavin as the catalyst. Liver cytosols were prepared from rats which received (i.p.) various amounts of Zn (5 mg/kg BW) or Cd (2.5 mg/kg BW). Purified MT was prepared by gel filtration and DEAE ion-exchange chromatography. Cytosols were heated (80/sup 0/C, 2 min) and centrifuged to obtain a supernatant. An appropriate amount of supernatant and various amounts of MT standard were electrophoresed (constant current, 20 mA per slab) for 9 hours. Gels were stained with Commassie Blue (R-250, 0.25%) for 12 hours and destained. Gels were scanned by densitometer and peaks heights were determined. Significantly linear standard curves (..mu..g MT vs. peak height) were established for both MTI and MTII. (Cd, Zn)-MTI migrated slower than Zn-MTI while mobilities for both (Cd, Zn)- and Zn-MTII were the same. The accumulation of MTI was consistently less than MTII in liver from both Zn- and Cd-injected rats. Their results suggest that electrophoretic analysis is an excellent system not only for quantitation but also for characterization of MT in rat tissue.

Lin, L.Y.; McCormick, C.C.

1986-03-05

294

Fundamentals of gel dosimeters  

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

295

Native American Health  

MedlinePLUS

... racial or ethnic group has specific health concerns. Differences in the health of groups can result from: Genetics Environmental factors Access to care Cultural factors On this page, you'll find links to health issues that affect Native-Americans.

296

Native American Museums: \\  

Microsoft Academic Search

Native Americans have opened some 250 museums and cultural centers in the last twenty years for several reasons: to re-possess their patrimony, memorize their culture and maintain their identity. Their museums are spaces of cultural and educational experience, replacing split families who no longer transmit traditional values orally. They safeguard oral testimonies of the old people (recordings) and the sacred

Gérard Selbach

297

Native American Youth Gangs  

Microsoft Academic Search

The number of Native American youth gangs has increased dramatically since the 1990s. These gangs bring increases in crime and pose unique challenges to tribal leaders and local police departments. Using an integrated theoretical perspective, this article connects cultural and historical factors to explain the emergence of gangs in Indian country, identify risk factors for gang involvement, and outline important

Matthew T. Theriot; Barbara “Sunshine” Parke

2008-01-01

298

Native Americans in Utah  

NSDL National Science Digital Library

This activity will help you learn about some of the early Native American inhabitants of Utah. Look at the following websites and see if you can find some information about one of the following groups of Native Americans in Utah. History of Utah Tribes Goshute Goshute Indians Utah History To Go: Goshute Indians Goshute Indian Reservation Utah History To Go: The Utes, Paiutes, and Goshutes Navajo People of the Colorado Plateau: Navajo (Dine) History of the Navajo Indians of Utah Navajo Navajo Indians Paiute Paiute Indians of Utah Paiute Native American Desert Peoples: The Paiute People Paiute Indians of Utah Utah History To Go--Piaute Indians Utah History To Go: The Utes, Paiutes, and Goshutes Shoshone Shoshone History of the Shoshone Indians Shoshoni Lewis and Clark: Native Americans--Shoshone Indians Ute Utah History To Go: Ute Indians People of the Colorado Plateau: The Ute Indians Story of the Ute Tribe Northern Ute Indian History Utah History To Go: The Utes, Paiutes, and Goshutes ...

Bates, Albion M.

2006-10-10

299

Native American Arts.  

National Technical Information Service (NTIS)

The video shows a richly varied and vivid impression of the unique historic and esthetic values, images, and traditions that are being rigorously developed by Native Americans in virtually every art form today. It presents a human survey of the modern eff...

1994-01-01

300

Rebuilding Native American Communities  

ERIC Educational Resources Information Center

The Wellbriety Movement in Native American communities draws on the wisdom and participation of traditional elders. Beginning with a basic community teaching called the Four Laws of Change and the Healing Forest Model, the Wellbriety Movement blends Medicine Wheel knowledge with the 12 Steps of Alcoholics Anonymous to provide culture-specific…

Coyhis, Don; Simonelli, Richard

2005-01-01

301

Native American Attrition Study.  

ERIC Educational Resources Information Center

The Albuquerque Technical-Vocational Institute (T-VI) is a post-secondary school offering full-time occupational training in 32 skill areas and a preparatory program for students inadequately prepared to enter a vocational major program. The institute enrolls a sizeable number of Native American students, but the attrition of these students is…

Moore, Carolyn

302

NATIVE HEALTH DATABASES: NATIVE HEALTH HISTORY DATABASE (NHHD)  

EPA Science Inventory

The Native Health Databases contain bibliographic information and abstracts of health-related articles, reports, surveys, and other resource documents pertaining to the health and health care of American Indians, Alaska Natives, and Canadian First Nations. The databases provide i...

303

NATIVE HEALTH DATABASES: NATIVE HEALTH RESEARCH DATABASE (NHRD)  

EPA Science Inventory

The Native Health Databases contain bibliographic information and abstracts of health-related articles, reports, surveys, and other resource documents pertaining to the health and health care of American Indians, Alaska Natives, and Canadian First Nations. The databases provide i...

304

Scattering from dilute ferrofluid suspensions in soft polymer gels.  

PubMed

Small angle neutron and x-ray scattering methods are used to investigate the structure of dilute suspensions of two different ferrofluid systems dispersed in soft polyacrylamide hydrogels. It is found that the particles in the fluid are fractal aggregates composed of smaller particles of radius ca. 5 nm. The fractal dimension is strongly dependent on sample, taking the value 1.7 in the first sample and 2.9 in the second sample. In the presence of a magnetic field the aggregates orient, but are restricted in both their translational and rotational freedom. The effect of the gel elasticity is treated as a hindrance to the orientation process. PMID:12636681

Teixeira, Alvaro V; Morfin, Isabelle; Ehrburger-Dolle, Françoise; Rochas, Cyrille; Geissler, Erik; Licinio, Pedro; Panine, Pierre

2003-02-01

305

Polymer gel dosimeters with reduced toxicity: a preliminary investigation of the NMR and optical dose-response using different monomers.  

PubMed

In this work, three new polymer gel dosimeter recipes were investigated that may be more suitable for widespread applications than polyacrylamide gel dosimeters, since the extremely toxic acrylamide has been replaced with the less harmful monomers N-isopropylacrylamide (NIPAM), diacetone acrylamide and N-vinylformamide. The new gel dosimeters studied contained gelatin (5 wt%), monomer (3 wt%), N,N'-methylene-bis-acrylamide crosslinker (3 wt%) and tetrakis (hydroxymethyl) phosphonium chloride antioxidant (10 mM). The NMR response (R2) of the dosimeters was analysed for conditions of varying dose, dose rate, time post-irradiation, and temperature during irradiation and scanning. It was shown that the dose-response behaviour of the NIPAM/Bis gel dosimeter is comparable to that of normoxic polyacrylamide gel (PAGAT) in terms of high dose-sensitivity and low dependence on dose rate and irradiation temperature, within the ranges considered. The dose-response (R2) of NIPAM/Bis appears to be linear over a greater dose range than the PAGAT gel dosimeter. The effects of time post-irradiation (temporal instability) and temperature during NMR scanning on the R2 response were more significant for NIPAM/Bis dosimeters. Diacetone acrylamide and N-vinylformamide gel dosimeters possessed considerably lower dose-sensitivities. The optical dose-response, measured in terms of the attenuation coefficient for each polymer gel dosimeter, showed potential for the use of optical imaging techniques in future studies. PMID:16825731

Senden, R J; De Jean, P; McAuley, K B; Schreiner, L J

2006-07-21

306

Alaska Native Parkinson's Disease Registry.  

National Technical Information Service (NTIS)

This registry initiates a program of epidemiological assessments of PS among Alaska Natives to study the natural history and clinical management of PS and establishes a database of Alaska native people with PS for public health research and educational pu...

B. A. Trimble

2007-01-01

307

Alaska Native Parkinson's Disease Registry.  

National Technical Information Service (NTIS)

This registry initiates a program of epidemiological assessments of PS among Alaska Natives to study the natural history and clinical management of PS, and establishes a database of Alaska native people with PS for public health, research and educational ...

B. A. Trimble

2008-01-01

308

Rapid (ten-minute) pore-gradient electrophoresis of proteins and peptides in Micrograd gels.  

PubMed

Precast gradient gels of short migration length (25 mm) have been developed to provide rapid electrophoretic separation without loss of resolution. These Micrograd gels have been prepared in gel ranges (conventional and unique) to match pore-gradient electrophoresis conditions to proteins/peptides ranging in size from several hundreds to millions. The Hylinx Micrograd gel combines an extreme gel range (6 to 48% polyacrylamide) with a novel crosslinker to provide sieving of polypeptides, and pore-limit electrophoresis of the smallest proteins (e.g. insulin monomer). All gel ranges (such as 3 to 30%) provide zone sharpening in routine analysis of conventional protein mixtures (e.g. serum) within 10 min electrophoresis at 200 to 300 volts. The gels are thin (1 mm) and thus stain quickly, but the gel cassette is of conventional overall width (83 mm), thus fitting many apparatus designs and accommodating 12 samples. The gels are finding valuable use in screening applications, requiring the electrophoretic analysis of many samples, and in cases where a rapid answer is needed, such as monitoring protein purification. The gels have proved particularly useful, in-house, for the latter application in developing Gradipore's new large-scale preparative electrophoresis system, the Gradiflow. PMID:1599958

Wrigley, C W; Margolis, J

1992-01-01

309

Enhanced removal of methylene blue and methyl violet dyes from aqueous solution using a nanocomposite of hydrolyzed polyacrylamide grafted xanthan gum and incorporated nanosilica.  

PubMed

The synthesis and characterization of a novel nanocomposite is reported that was developed as an efficient adsorbent for the removal of toxic methylene blue (MB) and methyl violet (MV) from aqueous solution. The nanocomposite comprises hydrolyzed polyacrylamide grafted onto xanthan gum as well as incorporated nanosilica. The synthesis exploits the saponification of the grafted polyacrylamide and the in situ formation of nanoscale SiO2 by a sol-gel reaction, in which the biopolymer matrix promotes the silica polymerization and therefore acts as a novel template for nanosilica formation. The detailed investigation of the kinetics and the adsorption isotherms of MB and MV from aqueous solution showed that the dyes adsorb rapidly, in accordance with a pseudo-second-order kinetics and a Langmuir adsorption isotherm. The entropy driven process was furthermore found to strongly depend on the point of zero charge (pzc) of the adsorbent. The remarkably high adsorption capacity of dyes on the nanocomposites (efficiency of MB removal, 99.4%; maximum specific removal Qmax, 497.5 mg g(-1); and efficiency of MV removal, 99.1%; Qmax, 378.8 mg g(-1)) is rationalized on the basis of H-bonding interactions as well as dipole-dipole and electrostatic interactions between anionic adsorbent and cationic dye molecules. Because of the excellent regeneration capacity the nanocomposites are considered interesting materials for the uptake of, for instance, toxic dyes from wastewater. PMID:24579659

Ghorai, Soumitra; Sarkar, Asish; Raoufi, Mohammad; Panda, Asit Baran; Schönherr, Holger; Pal, Sagar

2014-04-01

310

Electrophoretic extraction of proteins from two-dimensional electrophoresis gel spots  

DOEpatents

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

Zhang, Jian-Shi (Shanghai, CN); Giometti, Carol S. (Glenview, IL); Tollaksen, Sandra L. (Montgomery, IL)

1989-01-01

311

Cutaneous diseases in Native Americans.  

PubMed

Native Americans have a rich and complex heritage and culture. Although the genetic pool has changed with increasing integration with other Americans with different ancestry, there are important conditions that are unique to Native Americans, the most prominent example being actinic prurigo. The scientific literature dealing with Native American skin conditions is sparse and more studies are needed to understand more fully cutaneous disease in Native Americans. PMID:14717410

Cornelison, Raymond L

2003-10-01

312

Monosaccharide and oligosaccharide analysis of proteins transferred to polyvinylidene fluoride membranes after sodium dodecyl sulfate-polyacrylamide gel electrophoresis.  

PubMed

We have developed an intermediate method toward the complete carbohydrate analysis of proteins, which should be universally applicable to all proteins and independent of sample matrix. Using only Coomassie Blue-stained proteins which have been electroblotted onto polyvinylidene fluoride membranes, we report a strategy for: (i) determining unequivocally whether a protein is glycosylated; (ii) obtaining a complete monosaccharide composition; (iii) oligosaccharide mapping which separates most forms according to size, charge and isomerity; and (iv) sequentially releasing and analyzing specific classes of oligosaccharides with endoglycosidases. The method was shown to be applicable to a variety of well characterized soluble glycoproteins and to the membrane-bound protein, the gastric H+, K(+)-ATPase. The monosaccharide composition of the H+,K(+)-ATPase revealed the absence of N-acetylneuraminic or N-glycolylneuraminic acids and a monosaccharide composition which indicated O-linked sugar chains. Oligomannosidic/hybrid and biantennary oligosaccharides were sequentially released and analyzed from one electroblotted band of recombinant tissue plasminogen activator using endo-beta-N-acetylglucosaminidase H and endo-beta-N-acetylglucosaminidase F2, respectively. Sialylated polylactosamine structures were identified and quantified by analyzing high performance liquid chromatography profiles of oligosaccharides first released by peptide-N4-(N-acetyl-beta-D-glucosaminyl)asparagine amidase and then treated with endo-beta-galactosidase, using a single, stained band of recombinant erythropoietin. This recombinant erythropoietin was found to contain eight times more tetrasialylated oligosaccharides than previously reported (Sasaki, H., Bothner, B., Dell, A., and Fukuda, M. (1987) J. Biol. Chem. 262, 12059-12076); 47% of released oligosaccharides were identified as polylactosamine structures. PMID:8444888

Weitzhandler, M; Kadlecek, D; Avdalovic, N; Forte, J G; Chow, D; Townsend, R R

1993-03-01

313

Electrophoresis in Horizontal Polyacrylamide Gel. Second Report: Separation of the Components of Human Serum at Different Intervals.  

National Technical Information Service (NTIS)

An earlier report investigated the extent to which it was possible with a predetermined interval (interval from point of reference to pre-protein about 25 cm) to improve the separation of the components of normal human serum by alteration of the buffer co...

H. Biel O. Zwisler

1967-01-01

314

In situ fabrication of ionic polyacrylamide-based preconcentrator on a simple poly(methyl methacrylate) microfluidic chip for capillary electrophoresis of anionic compounds.  

PubMed

A simple and efficient method was developed for fabrication of an anionic sample preconcentrator on a channel of a commercial poly(methyl methacrylate) (PMMA)-made microchip using no photolithography or etching technique. The originality of our preconcentrator is based on simple photochemical copolymerization of monomers using the following procedure: All channels of the PMMA-made microchip were filled with gel solution comprising acrylamide, N,N'-methylene-bisacrylamide, and 2-acrylamide-2-methylpropanesulfonic acid with riboflavin as a photocatalytic initiator. In situ polymerization near the cross of the sample outlet channel was performed by irradiation with an argon ion laser beam, which is also used as the light source for fluorometric detection. The electrokinetic property and electric repulsion between sample components and anionic groups on the polyacrylamide gel layer produce, trap, and concentrate anions within a few minutes at the interface of the cathodic side of the gel layer. This method displays concentration factors as high as 10 (5). The availability of ionic preconcentrator was demonstrated by applying sensitive analysis of oligosaccharides labeled with 8-aminopyrene-1,3,6-trisulfonate and some glycoproteins labeled with fluorescein isothiocyanate under various buffer systems. PMID:18841941

Yamamoto, Sachio; Hirakawa, Shingo; Suzuki, Shigeo

2008-11-01

315

Southern elephant seal (Mirounga leonina)II. Studies of milk protein fractions by gel electrophoresis  

Microsoft Academic Search

Milk protein fractions during various stages of lactation in the southern elephant seal Mirounga leonina were analysed. Twelve milk samples were taken from ten females throughout the lactation period during 1990 and 1991 at Stranger\\u000a Point, King George Island, South Shetland Islands. Milk samples were subjected to polyacrylamide gel electrophoresis (PAGE).\\u000a Samples from different days of lactation gave similar qualitative

P. A. Ronayne de Ferrer; R. A. Gonzalez Colaso; M. E. I. Marquez; A. R. Carlini; D. F. Vergani; G. A. Daneri

1996-01-01

316

Method for quantitating cholesterol in subfractions of serum lipoproteins separated by gradient gel electrophoresis  

Microsoft Academic Search

Extensive heterogeneity in particle size distribution of serum lipoproteins of baboons was resolved by a procedure that combined\\u000a Sudan black B prestaining, polyacrylamide gradient gel electrophoresis (GGE), and quantitative densitometry. Each densitometric\\u000a scan represented a continuous distribution of the relative amount of cholesterol in a serum sample, as a function of the lipoprotein\\u000a particle size. For analytical purposes, each scan

M.-L. Cheng; C. M. Kammerer; W. F. Lowe; B. Dyke; J. L. VandeBerg

1988-01-01

317

Gradient gel electrophoretic characterization of humic substances and of bound residues of the herbicide bentazon  

Microsoft Academic Search

Radioactive herbicide compounds bound to humic material were separated by sodium dodecyl sulfate polyacrylamide gradient gel electrophoresis (SDS-PAGGE) and detected by autoradiography. SDS-PAGGE could be applied to separate humic substances according to their molecular masses, and to follow their time-dependent polymerisation. Autoradiographic analysis showed that the herbicide bentazon and its methyl and hydroxy derivatives were bound in humic substance fractions

W.-R Knauber; A. J Krotzky; B Schink

1998-01-01

318

Ocular Proteomics with Emphasis on Two-Dimensional Gel Electrophoresis and Mass Spectrometry  

Microsoft Academic Search

The intention of this review is to provide an overview of current methodologies employed in the rapidly developing field of ocular proteomics with emphasis on sample preparation, two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry (MS). Appropriate sample preparation for the diverse range of cells and tissues of the eye is essential to ensure reliable results. Current methods of protein

Nakul Mandal; Steffen Heegaard; Jan Ulrik Prause; Bent Honoré; Henrik Vorum

2010-01-01

319

Analysis of high density lipoproteins by a modified gradient gel electrophoresis method  

Microsoft Academic Search

A high resolution electrophoretic method has been developed to separate plasma high density lipoprotein (HDL) particles by size using 4-3076 polyacrylamide agarose (PAA) gradient gels, Sudan black B staining, and laser densitometry. Fourteen distinct HDL bands were observed with HDL-1 being designated as the largest particle and HDL-14 as the smallest particle. HDL-1 was similar in size to ferritin (Stokes

Zhengling Li; Judith R. McNamara; Jose M. Ordovas; Ernst J. Schaeferl

320

Alaska Native Knowledge Network  

NSDL National Science Digital Library

The Alaska Native Knowledge Network (ANKN) was established to serve as "a resource for compiling and exchanging information related to Alaska Native knowledge systems and ways of knowing." To achieve this goal, the website brings together publications, information about academic programs, curriculum resources, and a calendar of events. In the Curriculum Resources area, visitors can look over lesson plans, fact sheets, and classroom activities that weave together indigenous and Western knowledge systems. Moving on, the Publications area contains links to print publications for sale and a range of free titles, including "Guidelines for Culturally Responsible School Boards" and "Guidelines for Respecting Cultural Knowledge." Also, visitors should take a look at the Announcements area for updates about relevant training programs, workshops, and conferences.

321

Effect of linear polymer additives on the electroosmotic characteristics of agarose gels in ultrathin-layer electrophoresis.  

PubMed

Electroosmotic properties of agarose gels with low, medium, high and super high electroendosmosis (EEO) were evaluated based on the apparent electric field mediated mobility of a neutral, fluorescent marker under constant field strength using ultrathin-layer separation configuration. Electroosmotic flow mobility values were measured in different gel concentrations and also in the absence and the presence of various linear polymer additives. Under ultrathin-layer separation conditions, a slight decrease in electroosmotic flow mobility was observed with increasing agarose gel concentration of 1 to 3% for all agarose gels investigated. When linear polymer additives, such as linear polyacrylamide, hydroxyethyl cellulose or polyethylene oxide were added to 1% low electroendosmosis agarose gel, significant reduction of the electroosmotic flow properties were observed with increasing additive concentration. Effect of the intrinsic electroosmotic properties of the various electroendosmosis agaroses on the apparent mobilities and separation performance of double-stranded DNA fragments during automated ultrathin-layer agarose gel electrophoresis was also investigated. PMID:10486760

Lengyel, T; Guttman, A

1999-08-20

322

Applications of gel dosimetry  

Microsoft Academic Search

Gel dosimetry has been examined as a clinical dosimeter since the 1950s. During the last two decades, however, a rapid increase in the number of investigators has been seen, and the body of knowledge regarding gel dosimetry has expanded considerably. Gel dosimetry is still considered a research project, and the introduction of this tool into clinical use is proceeding slowly.

Geoffrey S Ibbott

2004-01-01

323

Long-term, buffer-less, wet gel storage in non-sealed polyethylene bags.  

PubMed

Electrophoresed gels are normally fixed, stained, destained, and dried. Drying is normally carried out with commercial gel dryers or by drying between two cellophane sheets held together by two acrylic frames. Here, we report that stained and destained gels (7.5, 10, or 15%, denaturing or native gels; 0.4 or 1.5 mm in thickness) could be stored wet, unsealed, and without any storage buffer for several months at room temperature within flexible polyethylene bags without significant shrinking or protein diffusion. The gel remains hydrated because of the de facto sealing achieved by the polyethylene sheets (PS) adhering airtightly to the gel on either sides. The microsaturated environment generated by the thin film of water molecules trapped between the gel and the PS, along with the nonporous nature of the PS, apparently protects the gel from cracking as well as shrinking significantly. The intensity of stained proteins increased during storage probably from the slight gel shrinkage observed. Wet gel storage is useful (a) when low abundance protein spots from multiple two-dimensional electrophoresis gels have to be excised for in-gel tryptic digestion or electroelution and (b) for wet gel autoradiography. In addition to avoiding dryer contamination and saving drying time, these bags prevent the moist gel from sticking to X-ray film. Such storage could also prove useful for electrophoretic transfer of fixed and stained gels. PMID:22585508

Kurien, Biji T; Scofield, R Hal

2012-01-01

324

Temperature effect on the non-Newtonian viscosity of an aqueous polyacrylamide solution  

SciTech Connect

A significant laminar heat transfer enhancement in a 2:1 rectangular duct occurs when a dilute aqueous polyacrylamide solution is used. There is strong evidence that this enhancement might be due to the effect of temperature on the viscosity of the polyacrylamide solution particularly at the low shear rate. However, there is no experimental data that reports this low shear viscosity over a range of temperature. The objective of the study is to report viscosity data which depend on both shear rate and temperature and to develop a method to correlate the viscosity data using a mathematical equation. A new temperature-dependent viscosity equation based on the Carreau model is introduced; this model takes into account the effects of shear-thinning non-Newtonian characteristics and temperature on the viscosity of the polyacrylamide solution.

Shin, Sehyun; Cho, Y.I. [Drexel Univ., Philadelphia, PA (United States). Dept. of Mechanical Engineering and Mechanics] [Drexel Univ., Philadelphia, PA (United States). Dept. of Mechanical Engineering and Mechanics

1993-11-01

325

Unified Theory for Gel Electrophoresis and Gel Filtration  

Microsoft Academic Search

Unified theory for gel electrophoresis and gel filtration: The behavior of macromolecules in gel filtration and gel electrophoresis may be predicted from Ogston's model for a random meshwork of fibers. This model has been generalized to apply to nonspherical molecules and to several gel types. The model provides equations for inter-relationships between mobility, partition coefficient, gel concentration, and molecular radius;

David Rodbard; Andreas Chrambach

1970-01-01

326

A study on freeze–thaw characteristics and microstructure of Chinese water chestnut starch gels  

Microsoft Academic Search

The influence of the repeatedly freeze-thawed (FT) treatment on the microstructure, crystallinity, thermal properties, textural properties and resistant starch content of Chinese water chestnut starch (CWCS) gels were investigated, using scanning electron microscopy (SEM), X-ray diffractometry, differential scanning calorimetry (DSC) and textural analysis (TA). The microstructure of the native starch gel was a compact and random phase. Freeze-thawed starch gels

Lan Wang; Zhihua Yin; Jia Wu; Zhida Sun; Bijun Xie

2008-01-01

327

Native Education 101: Basic Facts about American Indian, Alaska Native, and Native Hawaiian Education  

ERIC Educational Resources Information Center

This document contains information about education of indigenous American peoples, including: (1) Demographics; (2) Reservations and Native Lands Map; (3) Important Community Issues and Concepts; (4) Educational Issues for Native Students; (5) Type of Schools for Native Students; (6) Indian Education Legislation and Executive Orders; (7)…

National Indian Education Association, 2008

2008-01-01

328

Treatment of pulp and paper mill wastewater by polyacrylamide (PAM) in polymer induced flocculation.  

PubMed

The flocculation performances of nine cationic and anionic polyacrylamides with different molecular weights and different charge densities in the treatment of pulp and paper mill wastewater have been studied. The experiments were carried out in jar tests with the polyacrylamide dosages range of 0.5-15 mg l(-1), rapid mixing at 200 rpm for 2 min, followed by slow mixing at 40 rpm for 15 min and settling time of 30 min. The effectiveness of the polyacrylamides was measured based on the reduction of turbidity, the removal of total suspended solids (TSS) and the reduction of chemical oxygen demand (COD). Cationic polyacrlyamide Organopol 5415 with very high molecular weight and low charge density is found to give the highest flocculation efficiency in the treatment of the paper mill wastewater. It can achieve 95% of turbidity reduction, 98% of TSS removal, 93% of COD reduction and sludge volume index (SVI) of 14 ml g(-1) at the optimum dosage of 5 mg l(-1). SVI values of less than 70 m lg(-1) are found for all polyacrylamide at their respective optimum dosage. Based on the cost evaluation, the use of the polyacrylamides is economically feasible to treat the pulp and paper mill wastewaters. This result suggests that single-polymer system can be used alone in the coagulation-flocculation process due to the efficiency of the polyacrylamide. Sedimentation of the sludge by gravity thickening with settling time of 30 min is possible based on the settling characteristics of the sludge produced by Organopol 5415 that can achieve 91% water recovery and 99% TSS removal after 30 min settling. PMID:16431022

Wong, S S; Teng, T T; Ahmad, A L; Zuhairi, A; Najafpour, G

2006-07-31

329

Orthogonally bifunctionalised polyacrylamide nanoparticles: a support for the assembly of multifunctional nanodevices  

NASA Astrophysics Data System (ADS)

Polyacrylamide nanoparticles bearing two orthogonal reactive functionalities were prepared by reverse microemulsion polymerisation. Water-soluble photosensitisers and peptide or carbohydrate moieties were sequentially attached to the new nanospecies by orthogonal conjugations based on copper-catalysed azide-alkyne cycloaddition and isothiocyanate chemistry.Polyacrylamide nanoparticles bearing two orthogonal reactive functionalities were prepared by reverse microemulsion polymerisation. Water-soluble photosensitisers and peptide or carbohydrate moieties were sequentially attached to the new nanospecies by orthogonal conjugations based on copper-catalysed azide-alkyne cycloaddition and isothiocyanate chemistry. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11947a

Giuntini, F.; Dumoulin, F.; Daly, R.; Ahsen, V.; Scanlan, E. M.; Lavado, A. S. P.; Aylott, J. W.; Rosser, G. A.; Beeby, A.; Boyle, R. W.

2012-03-01

330

Microwave initiated synthesis of polyacrylamide grafted Psyllium and its application as a flocculant.  

PubMed

This paper reports a novel microwave initiated method for synthesis of polyacrylamide grafted Psyllium (Psy-g-PAM). Psyllium was modified through grafting of polyacrylamide (PAM) chains on it using microwave radiations only, in absence of any other free radical initiator. The grafting was confirmed by intrinsic viscosity study and characterization techniques like FTIR spectroscopy, elemental analysis (C, H, N, O and S) and SEM morphology study. Further, the flocculation efficacy of the synthesized graft copolymers was studied in kaolin and coal fine suspension through standard 'Jar test' procedure. PMID:22210527

Sen, Gautam; Mishra, Sumit; Rani, G Usha; Rani, Priti; Prasad, Rajesh

2012-03-01

331

Differences in the spatial and quantitative reproducibility between two second-dimensional gel electrophoresis systems.  

PubMed

Two-dimensional polyacrylamide gel electrophoresis (PAGE), together with 2-D gel electrophoresis (GE) analysis software, is a common technique to analyze a complex proteome. In order to accurately locate the differentially expressed proteins in human pituitary macroadenoma tissues in our long-term research program to clarify the molecular mechanisms of macroadenoma formation, a reproducible separation system is needed. An immobilized pH-gradient dry gel-strip (IPG strip) has been extensively used for first-dimensional isoelectric focusing (IEF), and has achieved a high degree of reproducibility in the IEF direction. For the second dimension (SDS-PAGE), different types of gel systems are available, including horizontal vs. vertical gel systems, and gradient vs. constant-percentage gels. A typical horizontal system is the Multiphor II system that analyzes one gel at a time, using a precast gradient gel (180 x 245 x 0.5 mm), and a typical vertical system is the Dodeca system, which analyzes up to 12 gels at a time, using usually a single-concentration gel (190 x 205 x 1 mm). The present study evaluated the spatial and quantitative reproducibility of the two systems for the separation of the complex human pituitary proteome. PDQuest software was used to analyze the digitized gel-image data, and SPSS statistical software was used to analyze the data. The results demonstrated a high percentage (>99%) of protein-spot matches within each electrophoretic system. The Dodeca gel system demonstrated better between-gel reproducibility for spot position, higher resolution in the Sodium dodecyl sulfate (SDS)-PAGE direction, lower gel background, better spot quality, and higher reproducibility of the spot volume. PMID:12783460

Zhan, Xianquan; Desiderio, Dominic M

2003-06-01

332

In-gel precipitation of enzymatically released phosphate.  

PubMed

The phosphate precipitation reaction using ammonium molybdate and triethylamine under low pH has been applied to gel-based assays for detecting phosphate-releasing enzymes. The sensitivity of the assay is 10 pmol Pi/mm2 of 1.5-mm-thick gel. The assay is applicable to enzymes with a wide range of optimal pH, from acid (pH 4.5) to alkaline phosphatase (pH 9.7), and to enzymes that use acid-labile substrates such as apyrase and glutamine synthetase. Using a negative staining approach, maltose phosphorylase, a phosphate-consuming enzyme, can also be detected. The assay was used to detect glutamine synthetase isoforms, separated by nondenaturing polyacrylamide gel electrophoresis from crude maize extracts. For downstream applications such as staining gels for proteins, the gels with precipitate should be incubated in 10 mM dithiothreitol or beta-mercaptoethanol until the precipitate is dissolved and then thoroughly washed in water. In comparison to calcium phosphate precipitation or the phosphomolybdate-malachite green method, this method is more sensitive. It is a very simple, rapid, versatile, reproducible, and inexpensive method that could be a useful tool in enzymological studies. PMID:15494139

Simonovi?, Ana D; Gaddameedhi, Shobhan; Anderson, Marc D

2004-11-15

333

Protein gel staining methods: an introduction and overview.  

PubMed

Laboratory scientists who encounter protein biochemistry in many of its myriad forms must often ask: is my protein pure? The most frequent response: run a denaturing SDS polyacrylamide gel. Running this gel raises another series of considerations regarding detection, quantitation, and characterization and so the next questions invariably center on suitable protein gel staining and detection methods. A total protein profile can be determined with the colorimetric methods embodied in Coomassie Blue and silver staining methods, or increasingly, with fluorescent stains. Protein quantitation can be done following staining, with fluorescence- and instrumentation-based methods offering the greatest sensitivity and linear dynamic range. Protein posttranslational modifications such as phosphorylation and glycosylation can be reliably determined with several fluorescence-based protocols. Staining and detection with two or more different stains can be done in series to establish relative profiles of modified versus total protein or to assess purity at two levels of quantitative sensitivity. The choice of staining method and protocol depends on the required rigor of detection and quantitation combined with available instrumentation and documentation capabilities. Other considerations for staining methods include intended downstream analytical procedures such as mass spectrometry or peptide sequencing, which preclude some methods. Nonfixative staining methods allow western blotting after gel staining. Laboratory custom and budget or intellectual curiosity may be the ultimate determinate of the chosen gel staining protocol. PMID:19892191

Steinberg, Thomas H

2009-01-01

334

Facial gel complication after dental injection: a case report.  

PubMed

Injectable gel is becoming increasingly popular for cosmetic reasons. The polyacrylamide gel (PAAG) is a permanent filler material used worldwide. In spite of the fact that the filler materials used today are considered quite safe, various complications have been reported in the literature. Hence PAAG use in the United States is not popular. As the area is very close to the dental field, a large complication potential is relatively considered following buccal dental injections. The aim of this article is to highlight a rare complication observed following a local anesthetic administration of a simple molar restoration in a healthy 33-year-old woman who had history of a filler augmentation in her cheek approximately 6 years ago. PMID:24436772

Pourdanesh, Fereydoun; Shams, Shahin; Sadeghi, Hasan Mir Mohammad

2013-12-01

335

Extraction and identification of electroimmunoprecipitated proteins from agarose gels.  

PubMed

A method for the identification of protein antigens captured in electroimmunoprecipitates was developed. Different antigen-antibody precipitates were generated by agarose gel immunoelectrophoresis. The immunoprecipitates were excised and various methods for extracting and dissociating the precipitates were systematically studied by analyzing for protein components of the extracts using peptide mass fingerprinting after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The optimal recovery of antigen was obtained by 24-h extraction at 37 degrees C using a minimal volume of 0.06 M Tris-HCl, 10% SDS (pH 7). This simple and robust method is useful for the characterization of antibody specificity. It can also be used to identify antigens generating unknown precipitates in crossed immunoelectrophoresis with polyspecific antisera, including human IgG-antigen complexes electroimmunoprecipitated by secondary antibodies. Thus, the method may prove useful as an additional technique in biomarker discovery. PMID:18048052

Beyer, Natascha Helena; Schou, Christian; Houen, Gunnar; Heegaard, Niels H H

2008-01-31

336

Gel electrophoretic analysis of DNA branched junctions.  

PubMed

Gel electrophoresis has provided much of the detailed information we have about the properties of DNA junctions, stable branched molecules formed from oligonucleotide or polynucleotide strands. Here we review these applications, and present the results of an electrophoretic investigation of conformationally restricted junctions formed by covalently connecting two different pairs of strands in a junction with four arms. Native gel electrophoresis is employed to establish the formation and stoichiometry of the multistrand complexes. Ferguson analysis of native gel mobility shows that junctions have retardation coefficients that are distinct from those of linear DNA duplexes. Denaturing gel electrophoresis is the primary tool for characterizing junctions that have been covalently linked together to form both linear and macrocyclic oligomers of junctions (oligojunctions). Radioactively labelled strands enable one to monitor the progress of the ligation reaction: both linear and closed cyclic molecules result, and these can be distinguished by applying Ferguson analysis to denaturing gels. Combinations of exonuclease III, restriction enzymes and sequencing reactions have been applied to oligojunction molecules, and the results are all analyzed on denaturing gels. Junctions containing intramolecular "tethers" that restrict the conformation freedom of the complex comprise a new system for analyzing the conformations of branched molecules. In these tethered junctions, the ability of arms to move relative to each other is restricted substantially by covalently connecting pairs of arms in the original complex with short, flexible loops. The two tethers used here constrain the helical domains of the structure to be roughly parallel or anti-parallel. In this article, we use Ferguson analysis to compare two tethered junctions with an untethered junction. At high gel concentrations, the mobility of the untethered complex is found to be closer to that of the molecule tethered anti-parallel than to the one tethered parallel. Curvature in the Ferguson plots for all three of these junctions is detected over a range of compositions. At low gel concentrations, differences in electrophoretic mobility persist, suggesting that the untethered junction differs in charge as well as conformational freedom from the tethered analogs. We expect that studies of this kind will be able to define the conformational repertoire of junctions of different kinds, and to explore the effects of electrophoresis on these states. PMID:2548837

Seeman, N C; Chen, J H; Kallenbach, N R

1989-01-01

337

Viscoelasticity of Semiflexible Biopolymer Solutions and Gels  

NASA Astrophysics Data System (ADS)

Plant and animal cells contain a complex polymeric network of filamentous proteins known as the cytoskeleton. A principal component of the cytoskeleton is the actin cortex, a gel-like network of F-actin filaments. This actin cortex is largely responsible for cell shape and stability, as well as important aspects of cell locomotion. Recently, a number of experimental studies have examined simple solutions of reconstituted F-actin in appropriate buffer. These in vitro models of the actin cortex have shown unusual viscoelasticity, when compared with more conventional polymeric materials. For instance, they tend to exhibit rather large shear moduli, and appear to have unusual dynamics, both of which have been attributed to the semiflexible nature of the constituent filaments. Here, we report a recent theoretical model that can account for the observed high shear modulus of actin networks.(F.C. MacKintosh, J. Käs, and P.A. Janmey, Phys. Rev. Lett. 75), 4425 (1995). We also report on recent experiments and theory of thermal fluctuations of embedded particles, as local viscoelastic probes in actin and polyacrylamide gels.(Work done in collaboration with F. Gittes, P.D. Olmsted, C.F. Schmidt, and B. Schnurr.)

Mackintosh, F. C.

1997-03-01

338

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

SciTech Connect

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

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

1992-09-01

339

Native American geometry  

NSDL National Science Digital Library

This website focuses on Native American use of the physical, proportional geometry that originates from the simple circle. Aimed at 4th to 9th grade teachers, the site is divided into four sections: foundations, anthropology, designs, and education. It was selected by Britannica.com, February 2000, as a best Internet site. Other keywords: geometric shapes, geometric constructions, proportional geometry, proportional constants, polygons, hexagons, equilateral triangles, dodecagons, squares, octagons, connect the dot, art, square roots, irrational numbers, non-random geometry. (Includes about 25 relevant website links and 50 published references)

2007-12-12

340

Horizontal two-dimensional electrophoresis of complex DNA samples using precast gel systems.  

PubMed

We have developed a simplified procedure for the separation of enzyme-digested genomic DNA, or of complex mixtures of cloned DNA, into two dimensions. The procedure relies on the use of precast gels for horizontal electrophoretic separations. Precast agarose-type gels are used for the first-dimensional separation of fragments based on size. Precast polyacrylamide gels are used for the second-dimensional separation of fragments. The separated fragments are subjected to enzymatic digestion in situ prior to their transfer to the second-dimensional gel. Applications of this procedure include the analysis of DNA libraries, analysis of yeast artificial chromosomes (YACs) as well as other similar preparations, and the screening of genomic DNA for the occurrence of multi-copy DNA fragments as in the case of genomic amplifications in cancer. PMID:10380763

Schickle, H; Lamb, B J; Hanash, S M

1999-06-01

341

Ocular Proteomics with Emphasis on Two-Dimensional Gel Electrophoresis and Mass Spectrometry  

PubMed Central

The intention of this review is to provide an overview of current methodologies employed in the rapidly developing field of ocular proteomics with emphasis on sample preparation, two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry (MS). Appropriate sample preparation for the diverse range of cells and tissues of the eye is essential to ensure reliable results. Current methods of protein staining for 2D-PAGE, protein labelling for two-dimensional difference gel electrophoresis, gel-based expression analysis and protein identification by MS are summarised. The uses of gel-free MS-based strategies (MuDPIT, iTRAQ, ICAT and SILAC) are also discussed. Proteomic technologies promise to shed new light onto ocular disease processes that could lead to the discovery of strong novel biomarkers and therapeutic targets useful in many ophthalmic conditions.

2010-01-01

342

NativeWeb  

NSDL National Science Digital Library

A number of websites are dedicated to providing information about various groups and organizations, and NativeWeb just happens to be one of the best known sites dedicated âÂÂto disseminating information from and about indigenous nations, peoples, and organizations around the world.â For the past ten years, the site has grown tremendously, and it functions as a very nice clearinghouse for materials ranging from ongoing archaeological excavations to higher education grants for organizations that serve indigenous peoples. With its relatively clean design, the site is easy to navigate, and first-time visitors will appreciate their âÂÂIn the Newsâ section, which offers selected recent news items that relate to indigenous and native groups around the world. The real substance of the site can be found in the tremendous âÂÂResourcesâ section, which contains thematically organized links to high-quality online materials. Finally, visitors can also sign up to receive updates when new resources are added to the site.

343

Imprinting effect of protein-imprinted polymers composed of chitosan and polyacrylamide: A re-examination  

Microsoft Academic Search

In this paper the imprinting effects recently reported with protein-imprinted polymers based on chitosan and polyacrylamide are re-assessed. Molecularly imprinted polymers (MIPs) from which the embedded template molecules were removed by washing with a solution of sodium dodecyl sulfate and acetic acid were prepared. In batch template rebinding experiments, the MIPs displayed quite high template binding capacity as reported previously.

Guo-Qi Fu; Hao Yu; Jing Zhu

2008-01-01

344

Polyacrylamide and straw residue effects on irrigation furrow erosion and infiltration  

Microsoft Academic Search

Water-soluble anionic polyacrylamide (PAM) is a highly effective erosion deterrent in furrow irrigation, but little is known about the effect of plant residues on PAM efficacy. We hypothesized that increasing plant residue in irrigation furrows may alter PAM's ability to control erosion. Furrows with 10 g (485 kg ha-') on treated area and 3o g (1490 kg ha-') wheat straw

R. D. Lentz; D. L. Bjorneberg

2003-01-01

345

POLYACRYLAMIDE TREATMENTS FOR REDUCING SEEPAGE IN SOIL-LINED RESERVOIRS: A FIELD EVALUATION  

Microsoft Academic Search

Irrigation water supplies are becoming limited, and there is a need to extend the usefulness of current water resources. Previous laboratory studies demonstrated that certain water-soluble polyacrylamide solution (WSPAM) and cross-linked PAM granule (XPAM) treatments effectively reduced infiltration into soils. We evaluated the efficacy of these treatments for reducing water seepage losses in an unlined irrigation reservoir. Five treatments were

R. D. Lentz; D. C. Kincaid

346

Polyacrylamide–clinoptilolite\\/Y-zeolite composites: Characterization and adsorptive features for terbium  

Microsoft Academic Search

The composites of natural (clinoptilolite) and synthetic zeolite (Z and YZ) with polyacrylamide (PAAm) were synthesized and characterized by FT-IR, TGA, XRD, SEM and PZC analysis. The adsorptive features of the minerals and its composites were investigated for Tb analogues to the rare earth elements (REs) by isotopic tracer method, 160Tb was the radiotracer. The composites were the hybrid formations

Demet Bayba?; Ulvi Ulusoy

2011-01-01

347

Study on the Dynamic Rheometry and Swelling Properties of the Polyacrylamide\\/Laponite Nanocomposite Hydrogels in Electrolyte Media  

Microsoft Academic Search

Polyacrylamide\\/laponite\\/chromium triacetate nanocomposite (NC) hydrogels were prepared by incorporation of the laponite nanoparticles in partially hydrolyzed polyacrylamide followed by crosslinking of their aqueous solutions with chromium triacetate. Influence of nanoparticle, crosslinker, polymer concentrations and gelation media (water) temperature, salinity and rheometer frequency on the viscoelastic behavior of the NC hydrogels were studied by probing the network properties. In addition, swelling

Jamal Aalaie; Marjan Youssefi

2011-01-01

348

Development of Polymer Gel Systems to Improve Volumetric Sweep and Reduce Producing Water/Oil Ratios  

SciTech Connect

Gelled polymer treatments are applied to oil reservoirs to increase oil production and to reduce water production by altering the fluid movement within the reservoir. This report describes the results of the third year of a 42 month research program that is aimed at an understanding of gelation chemistry and the fundamental mechanisms that alter the flows of oil and water in reservoir rocks after a gel treatment. Work focused on a widely applied system in the field, the partially hydrolyzed polyacrylamide-chromium acetate gel. Gelation occurs by network formation through the crosslinking of polyacrylamide molecules as a result of reaction with chromium acetate. Pre-gel aggregates form and grow as reactions between chromium acetate and polyacrylamide proceed. A mathematical model that describes uptake and crosslinking reactions as a function of time was derived. The model was probability based and provides molecular-weight averages and molecular-weight distributions of the pre-gel aggregates as a function of time and initial system conditions. A liquid chromatography apparatus to experimentally measure the size and molecular weight distributions of polymer samples was developed. The method worked well for polymer samples without the chromium crosslinker. Sample retention observed during measurements of gelant samples during the gelation process compromised the results. Other methods will be tested to measure size distributions of the pre-gel aggregates. Dissolution of carbonate minerals during the injection of gelants causes the pH of the gelant to increase. Chromium precipitates from solution at the higher pH values robbing the gelant of crosslinker. Experimental data on the transport of chromium acetate solutions through dolomite cores were obtained. A mathematical model that describes the transport of brine and chromium acetate solutions through rocks containing carbonate minerals was used to simulate the experimental results.

G. Paul Willhite; Stan McCool; Don W. Green; Min Cheng; Feiyan Chen

2005-04-03

349

North American Native Plant Society  

NSDL National Science Digital Library

The North American Native Plant Society (NANPS) is dedicated "to the study, conservation, cultivation and restoration of native plants." The NANPS website lists plant sources by region, and invites native plant growers to submit a listing for no charge. The site provides information about upcoming events across Canada and the United States; scholarship opportunities; related associations by region; publications; membership; and more. NANPS also maintains a message board, and offers information about a number of native plants including Walking Fern, Bottlebrush Buckeye, Musclewood, Lilies, and Smaller Fringed Gentian. NANPS runs a Seed Exchange for members as well.

2007-08-28

350

The Handling of Impositions in Native-Non-Native Conversations.  

ERIC Educational Resources Information Center

Some ways are discussed in which impositions (potentially face-threatening linguistic actions such as offers, requests, or complaints) are jointly negotiated by native (NS) and non-native speakers (NNS) in the process of interaction. Attention is focused on connected discourse features that are as much a part of the linguistic action negotiation…

Piirainen-Marsh, Arja

351

Our Native Ways: The Voices of Native American Youth.  

ERIC Educational Resources Information Center

To celebrate the "Decade of the Indigenous Peoples," this issue of a nonprofit children's magazine includes art and writings by Native American youth who share their ways of looking at and living life. Emphasizes the distinct customs, traditions, languages, and folklore of the different Native Nations and Tribes. (LZ)

Toke, Arun Narayan, Ed.; And Others

1994-01-01

352

Electrophoresis gel media: the state of the art.  

PubMed

Some unique events have occurred in the last few years which might revolutionize the field of polyacrylamide gel electrophoresis. While it was widely recognized that such matrices could normally be cast with a small pore size distribution, typically of the order of a few nanometers diameter (for protein sieving), recent developments suggest that "macroporous" gels could also be produced in the domain of polyacrylamides. If constraints to chain motion are imposed during gel polymerization, large-pore structures can be grown. Such constraints can originate either from low temperatures or from the presence of preformed polymers in the gelling solution; in both cases, the growing chains are forced to "laterally aggregate" via inter-chain hydrogen bond formation. Upon consumption of pendant double bonds, such bundles are frozen in the three-dimensional space by permanent cross-links. As an additional development, a novel photopolymerization system is described, comprising a cationic dye (methylene blue) and a redox couple (sodium toluene sulfinate, a reducer, and diphenyliodonium chloride, a mild oxidizer). Methylene blue catalysis is characterized by a unique efficiency, ensuring >96% conversion of monomers, even in hydro-organic solvents and in the presence of surfactants, which normally quench or completely inhibit the persulphate-driven reaction. In addition, methylene blue-sustained photopolymerization can be operated in the entire pH 3-10 interval, where most other systems fail. Perhaps the most striking novelty in the field is the appearance of a novel monomer (N-acryloylaminopropanol, AAP) coupling a high hydrophilicity with a unique resistance to alkaline hydrolysis. Given the fact that a poly(AAP) matrix is 500 times more stable than a poly(acrylamide) gel, while being twice as hydrophilic, it is anticipated that this novel chemistry will have no difficulties in replacing the old electrophoretic anticonvective media. The review ends with a glimpse at novel sieving media in capillary zone electrophoresis: polymer networks. Such media, by providing an almost infinite range of pore sizes, due to the absence of a rigid support, allow sieving mechanisms to be operative over a wide interval of particle sizes, even up to genomic DNA. Viscous solutions of polymer networks, made with the novel poly(AAP) chemistry, allow repeated use of the same separation column, well above 50 injections. Silica-bound poly(AAP) chains provide effective quenching of electroosmosis and >200 analyses by isoelectric focusing. PMID:9392368

Righetti, P G; Gelfi, C

1997-10-10

353

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

PubMed

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

Gregusova, Michaela; Docekal, Bohumil

2011-01-17

354

Gel absorption-based sample preparation for the analysis of membrane proteome by mass spectrometry.  

PubMed

A gel absorption-based sample preparation method for shotgun analysis of membrane proteome has been developed. In this new method, membrane proteins solubilized in a starting buffer containing a high concentration of sodium dodecyl sulfate (SDS) were directly entrapped and immobilized into gel matrix when the membrane protein solution was absorbed by the vacuum-dried polyacrylamide gel. After the detergent and other salts were removed by washing, the proteins were subjected to in-gel digestion and the tryptic peptides were extracted and analyzed by capillary liquid chromatography coupled with tandem mass spectrometry (CapLC-MS/MS). The results showed that the newly developed method not only avoided the protein loss and the adverse protein modifications during gel embedment but also improved the subsequent in-gel digestion and the recovery of tryptic peptides, particularly the hydrophobic peptides, thereby facilitating the identification of membrane proteins, especially the integral membrane proteins. Compared with the conventional tube-gel digestion method, the newly developed method increased the numbers of identified membrane proteins and integral membrane proteins by 25.0% and 30.2%, respectively, demonstrating that the method is of broad practicability in gel-based shotgun analysis of membrane proteome. PMID:20494643

Zhou, Jian; Xiong, Jixian; Li, Jianglin; Huang, Sha; Zhang, Hai; He, Quanze; Lin, Yong; Chen, Ping; Wang, Xianchun; Liang, Songping

2010-09-15

355

Dialysis as a method of obtaining neutral collagen gels.  

PubMed

Collagen gels are useful materials for medicine and tissue engineering. They are generally obtained by chemical cross-linking of the protein chains. However, other kinds of interactions can also stabilize the structure. In our investigations we employed dialysis against deionised water as a method of neutralization of collagen solution. This promoted the creation of stable, flexible, transparent gel composed only of collagen and water. The FTIR-ATR spectroscopy showed that changing pH of the solution caused organization of collagen chains into triple-helical motifs similar to native protein. As a result, thermal stability of the material improved and the surface was more polar than in case of collagen film obtained from acidic solution. The freeze-drying of the gel provided the relatively stiff, porous material, which returned to its original shape after deformation. We expect that the method of obtaining neutral collagen gels can be widely applied for preparation of scaffolds for tissue engineering. PMID:24857466

Skopinska-Wisniewska, Joanna; Olszewski, Kamil; Bajek, Anna; Rynkiewicz, Aldona; Sionkowska, Alina

2014-07-01

356

Native American Adolescent Career Development.  

ERIC Educational Resources Information Center

Career interests, efficacy expectations, and parental support were measured for 120 Native American and 134 Caucasian adolescents. Native Americans had greater interest in Realistic and Commercial occupations and those requiring high school diploma, trade school, or two-year postsecondary education. They were similar to Caucasians in range of…

Turner, Sherri L.; Lapan, Richard T.

2003-01-01

357

Native Americans as Sports Mascots.  

ERIC Educational Resources Information Center

Discusses the controversy over whether sport teams should use Native American logos, mascots, or native symbols. Suggests that by implementing role-reversal techniques (putting the nonnative people in the same place) uncaring sports fans may recognize the disrespect involved; offers a hypothetical newspaper article that illustrates the…

Muir, Sharon Pray

1999-01-01

358

Native American Adult Reader II.  

ERIC Educational Resources Information Center

This reader, one of three designed to provide adults in basic education/GED programs with meaningful materials based on Native American cultures, includes selections appropriate for intermediate reading ability (grades 4-6). The twelve readings focus on culture, history, and contemporary concerns of Native Americans. Each selection includes a…

King, Lovern Root, Ed.

359

Native American Adult Reader III.  

ERIC Educational Resources Information Center

This reader, one of three designed to provide adults in basic education/GED programs with meaningful material based on Native American cultures, includes selections appropriate for advanced reading ability (grade 7 and above). The twelve readings focus on culture, history, and contemporary concerns of Native Americans. Each selection includes a…

King, Lovern Root, Ed.

360

Native Language Literacy Screening Device.  

ERIC Educational Resources Information Center

The purpose the Native Language Literacy Screening Device (NLLSD) is to give English for Speakers of Other Languages (ESOL) practitioners a sense of the native language literacy levels of learners coming into their programs. This is worth knowing because when learners have had limited schooling in their first language instructional strategies used…

Hudson River Center for Program Development, Glenmont, NY.

361

Employment and Urban Native Canadians.  

ERIC Educational Resources Information Center

Measured differences in employment issues between native Canadian Indians and a nonnative comparison group in Toronto. Given similar circumstances, found Native Canadians less formally educated and skill trained than nonnatives of comparable age, sex, and education. Respondents under 25 and over 50 earned substantially less. (Author)

Abrahams-Maclachlan, Caryl; And Others

1982-01-01

362

Alaska Native Personal Leadership Program.  

ERIC Educational Resources Information Center

Describes the Alaska Native Leadership Program (ANLP), designed to recruit and retain Alaska Native college students. The year-long program includes an orientation, a two-semester class on self-exploration, skill-building, educational and career paths, and social activities. Student satisfaction with the program is indicated. (MMU)

Curtis, Steven; Curtis, Jane; Halfon, Linda; Holt, Teresa; Knapp, Marilyn; Konshin, Luda; Schroeder, Tim; Navitsky, Mary Anne; Sunde, Elaine

1998-01-01

363

Marriage and Commitment. Native Viewpoints.  

ERIC Educational Resources Information Center

Describes a wedding ceremony combining Canadian Native and Roman Catholic traditions that could be a model for Indian education. Asserts that Canadian natives must continue to gain control and autonomy over their own schools. Discusses responsibilities and interrelationships between the school and parents, students, and teachers. (CFR)

Steinhauer, Noella

1994-01-01

364

Native American Foods and Cookery.  

ERIC Educational Resources Information Center

Native Americans had a well-developed agriculture long before the arrival of the Europeans. Three staples--corn, beans, and squash--were supplemented with other gathered plants or cultivated crops such as white potatoes, sweet potatoes, pumpkins, and peanuts. Native Americans had no cows, pigs, or domesticated chickens; they depended almost…

Taylor, Tom; Potter, Eloise F.

365

Ohiyesa's Path: Reclaiming Native Education  

ERIC Educational Resources Information Center

As Natives have assumed increasing authority and responsibility for tribal and federally funded and administered schools, a more balanced and enlightened view is emerging. Notable among these events is the recognition of the critical need to shift emphasis to the untapped heritage of more recently recognized and acknowledged Native American…

James, Adrienne Brant; Renville, Tammy

2012-01-01

366

Higher resolution microplate array diagonal gel electrophoresis: application to a multiallelic minisatellite.  

PubMed

The 5' polymorphic region of the insulin (INS, MIM# 176730) gene contains a variable tandem repetition of 14-15 bp (a variable number of tandem repeats (VNTR) locus). After PCR amplification, we achieved precise sizing of class I alleles (range 641 to 843 bp) on 96-well open-face polyacrylamide microplate array diagonal gel electrophoresis (MADGE) gels, obtaining resolution of the 2% mobility difference which represents one tandem repeat. PCR products were run double-stranded, but no additional bands were generated except in the case of differences of three, two, and one repeat between alleles; none compromised allele identification, and in the latter case the heteroduplex was a useful confirmation signal. No end labelling of primers was required, as the sensitive Vistra Green intercalating dye for double strands was used for visualization of bands from diluted samples. Duracryl, a high mechanical-strength polyacrylamide derivative, proved to have good resolution properties for electrophoresis. A co-run ladder ensured precise binning without inter-lane variability. Simultaneous electrophoresis of gels in a thermostatically controlled tank allowed up to 1,000 samples to be run in 90 min. Gels were analyzed using a FluorImager 595 fluorescent scanning system, and alleles identified using a combination of Phoretix software for band migration measurement and Microsoft Excel to compute allele sizes. Unlike other systems for minisatellite allele sizing, throughput was not limited (in time or cost) by electrophoresis. PMID:10862086

O'Dell, S D; Chen, X; Day, I N

2000-01-01

367

Two-Dimensional Gel Electrophoresis Analysis of the Response ofPseudomonas putidaKT2442 to 2Chlorophenol  

Microsoft Academic Search

The effects of exposure ofPseudomonas putidaKT2442 to 2-chlorophenol as a model for the chemical stress response were examined by two-dimensional polyacrylamide gel electrophoresis. Individual protein concen- trations were determined at 45, 65, and 95 min following the addition of 2-chlorophenol at a concentration of 1.63 mM to exponentially growing cultures ofP. putidaKT2442 by silver staining the separated proteins. The changes

CLAUDIO G. LUPI; TERESA COLANGELO; ANTHONY MASON

1995-01-01

368

The Preparation of BHb-Molecularly Imprinted Gel Polymers and Its Selectivity Comparison to BHb and BSA  

Microsoft Academic Search

Molecularly imprinted gel polymer (MIP) for the selective imprinting of bovine hemoglobin (BHb) was prepared in aqueous media by bulk polymerization using polyacrylamide matrix. The synthesis conditions of BHb-MIP were investigated, which involved the interaction of functional monomers and template protein in different molar ratio, solution pH, and ionic strength. The adsorption experiments indicated that BHb-MIP had a high affinity

Qingqing Gai; Feng Qu; Yukui Zhang

2010-01-01

369

Characterization of Network Structure of Polyacrylamide Based Hydrogels Prepared By Radiation Induced Polymerization  

NASA Astrophysics Data System (ADS)

In this study network structure of polyacrylamide based hydrogels prepared by radiation induced polymerization has been investigated. Polyacrylamide based hydrogels in the rod form were prepared by copolymerization of acrylamide(AAm) with hydroxyl ethyl methacrylate(HEMA) and methyl acrylamide(MAAm) in the presence of cross-linking agent and water by gamma rays at ambient temperature. Molecular weight between cross-links and effective cross-link density of hydrogels were calculated from swelling as well as shear modulus data obtained from compression tests. The results have shown that simple compression analyses can be used for the determination of effective cross-link density of hydrogels without any need to some polymer-solvent based parameters as in the case of swelling based determinations. Diffusion of water into hydrogels was examined by analyzing water absorption kinetics and the effect of network, structure on the diffusion type and coefficient was discussed.

Mahmudi, Naim; ?en, Murat; Güven, Olgun; Rendevski, Stojan

2007-04-01

370

Polyacrylamide grafted Agar: synthesis and applications of conventional and microwave assisted technique.  

PubMed

Polyacrylamide grafted Agar (Ag-g-PAM) has been successfully synthesized by conventional method and microwave assisted method. The former method employs ceric ammonium nitrate (CAN) as the free radical initiator while the latter uses the combination of ceric ammonium nitrate (CAN) and microwave irradiation. The synthesized graft copolymers have been characterized by elemental analysis (C, H, N, O and S), FTIR spectroscopy, intrinsic viscosity measurement and scanning electron micrograph (SEM); taking agar as a reference. Flocculation efficacy of synthesized graft copolymers was studied in kaolin suspension and in waste water through 'Jar test' procedure. In the present investigation, we have observed that polyacrylamide grafted agar synthesized by microwave assisted technique shows superior properties than conventional technique. These properties are reported in terms of intrinsic viscosity, flocculation efficacy and pollutant load reduction of waste water. PMID:22840002

Rani, G Usha; Mishra, Sumit; Sen, Gautam; Jha, Usha

2012-10-01

371

Use of the diffusive gradients in thin films technique (DGT) with various diffusive gels for characterization of sewage sludge-contaminated soils  

Microsoft Academic Search

The diffusive gradients in thin film technique (DGT) was used for characterization of South Moravian arable soils (sampling\\u000a sites Zlín, Tu?any, and Chrlice) amended by sewage sludge in the 1980s. Two types of polyacrylamide diffusive gel with different\\u000a pore size (APA gels—cross-linked with agarose and RG gels—cross-linked with bis-acrylamide) were employed. The (bio)available\\u000a parts of Cd, Cu, and Ni and

Vlad?na Kova?íková; Hana Do?ekalová; Bohumil Do?ekal; Martina Podborská

2007-01-01

372

Sedimentation of titanium dioxide suspension in the presence of polyacrylamide flocculants  

Microsoft Academic Search

The kinetics of sedimentation of titanium dioxide suspension in aqueous and water-salt media is studied in the presence of\\u000a high-molecular-weight flocculants — polyacrylamide and ionic (anionic and cationic) acrylamide copolymers. Data are obtained\\u000a on the influence of flocculant concentration, the chemical nature of repeating units in polymer chains of acrylamide (co)polymers,\\u000a and the order of the addition of active components

V. E. Proskurina; V. A. Myagchenkov

2007-01-01

373

Uranium Sorption by Pseudomonas Biomass Immobilized in Radiation Polymerized Polyacrylamide Bio-Beads  

Microsoft Academic Search

A Pseudomonas strain identified as a potent biosorbent of uranium (U) and thorium was immobilized in radiation-induced polyacrylamide matrix for its application in radionuclide containing wastewater treatment. The immobilized biomass exhibited a high U sorption of 202 mg g dry wt. with its optimum at pH 5.0. A good fit of experimental data to the Freundlich model suggested multilayered uranium

S. F. DSOUZA; PINAKI SAR; SUFIA K. KAZY; B. S. KUBAL

2006-01-01

374

Dynamic rheology studies of in situ polymerization process of polyacrylamide–cellulose nanocrystal composite hydrogels  

Microsoft Academic Search

A series of dynamic small-amplitude oscillatory shear experiments for in situ polymerization process of polyacrylamide–cellulose\\u000a nanocrystal (PAM–CNC) nanocomposite hydrogels were performed to investigate the relationship between rheological properties\\u000a and synthesis parameters including chemical cross-linker concentration, polymerization temperature, initiator concentration,\\u000a and CNC aspect ratios. The results showed that CNCs accelerated the onset of gelation (t\\u000a onset) and acted as a multifunctional

Chengjun Zhou; Qinglin Wu; Quanguo Zhang

2011-01-01

375

Effects of polyacrylamide soil conditioner on the iron status of soybean plants. [Glycine max  

SciTech Connect

An iron-inefficient cultivar of soybean (Glycine max L. Merr. Bragg cv. PI-54619-5-1 was grown in two different calcareous soils, a Natrargid and a Torrifluvents, to determine if improvement of soil aeration with a synthetic polyacrylamide as a soil conditioner would decrease the tendency of the cultivar to lime-induced chlorosis. The results suggest that when soil is well aerated with good drainage from use of the soil conditioner, the iron status of plants is improved.

Wallace, A.; Wallace, G.A.; Abouzamzam, A.M.; Char, J.W.

1986-05-01

376

Synthesis of Plantago Psyllium Mucilage Grafted Polyacrylamide and its Flocculation Efficiency in Tannery and Domestic Wastewater  

Microsoft Academic Search

A graft copolymer of P.psyllium mucilage and polyacrylamide has been synthesized in the presence of nitrogen using ceric ion-nitric acid redox initiator. This grafted copolymer was tested for its flocculation efficiency in Tannery and Domestic wastewater by the standard Jar Test method. The effects of polymer concentration, contact time and pH on percent removal of solid wastes from Tannery and

Monika Agarwal; Rajani Srinivasan; Anuradha Mishra

2002-01-01

377

Use of polyacrylamide-grafted Plantago psyllium mucilage as a flocculant for treatment of textile wastewater  

Microsoft Academic Search

The chemical modification of Plantago psyllium mucilage (Psy), an anionic polysaccharide, was done by grafting polyacrylamide (PAM) chains to prepare a graft-copolymer (Psy- g-PAM). It was synthesized in the presence of nitrogen using ceric ammonium nitrate–nitric acid redox initiator and characterized by IR spectroscopy, scanning electron microscopy and viscosity measurements. This grafted copolymer was tested for its flocculation efficiency in

Anuradha Mishra; Rajani Srinivasan; Malvika Bajpai; Rashmi Dubey

2004-01-01

378

Irradiation mediated synthesis of a superabsorbent hydrogel network based on polyacrylamide grafted onto salep  

NASA Astrophysics Data System (ADS)

The synthesis and swelling behavior of a new superabsorbent hydrogel based on natural salep grafted with polyacrylamide is described. The new biopolymer was synthesized via simultaneous crosslinking and graft copolymerization of acrylamide monomer onto a salep backbone using radiochemical methods. Various parameters such as relative contents of salep and acrylamide, as well as total dose of ?-rays were examined. The best synthesis condition is reported and a mechanism for superabsorbent hydrogel formation suggested. Factors affecting the swelling behavior of hydrogel were also studied.

Bardajee, Ghasem Rezanejade; Pourjavadi, Ali; Soleyman, Rouhollah; Sheikh, Nasrin

2008-09-01

379

An intercalated hybrid of polyacrylamide\\/layered double hydroxide prepared via in situ intercalative polymerization  

Microsoft Academic Search

A new intercalated hybrid of polyacrylamide (PAM)\\/layered double hydroxide (LDH) prepared via in situ intercalative polymerization procedure is reported. LDH with counterion ion of nitrate or dodecyl sulfate anion was employed for comparison. The obtained PAM\\/LDH hybrid was characterized by X-ray diffraction, infrared spectra, differential scanning microcalorimetry and X-ray photoelectron spectrum. The results reveal that the LDH modified with dodecyl

Pingjun Fu; Guangming Chen; Jun Liu; Jiping Yang

2009-01-01

380

Polyacrylamide preparations for protection of water quality threatened by agricultural runoff contaminants  

Microsoft Academic Search

Waste streams associated with a variety of agricultural runoff sources are major contributors of nutrients, pesticides and enteric microorganisms to surface and ground waters. Water soluble anionic polyacrylamide (PAM) was found to be a highly effective erosion-preventing and infiltration-enhancing polymer, when applied at rates of 1–10 g m?3 in furrow irrigation water. Water flowing from PAM treated irrigation furrows show

James A. Entry; R. E. Sojka; Maribeth Watwoodb; Craig Ross

2002-01-01

381

Reducing Phosphorus Losses from Surface-Irrigated Fields: Emerging Polyacrylamide Technology  

Microsoft Academic Search

ABSTRACT Most P losses from surface-irrigated fields occur via runoff, are associated with eroded sediment, and can be minimized by eliminating irrigation-induced erosion. A convenient new practice that eliminates furrow irrigation-induced soil losses uses a high molecular weight, anionic polyacrylamide (PAM) applied to initial irrigation inflows. We hypothesized that, compared to control furrows, PAM treatment would reduce field losses of

R. D. Lentz; R. E. Sojka; C. W. Robbins

1998-01-01

382

Flocculation and dewatering of kaolin suspensions in the presence of polyacrylamide and surfactants  

Microsoft Academic Search

Flocculation, as a result of the interaction between non-ionic polyacrylamide polymer (PAM-N) and kaolin surface in aqueous suspension, has been discussed both in the absence and in the presence of surfactants namely, cationic cetyl trimethyl ammonium bromide (CTAB), anionic sodium dodecyl sulphate (SDS) and non-ionic TX 100. The results of separation properties have been discussed in the light of kaolin

L Besra; D. K Sengupta; S. K Roy; P Ay

2002-01-01

383

34 CFR 300.29 - Native language.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Native language. 300.29 Section 300.29 Education ...Definitions Used in This Part § 300.29 Native language. (a) Native language , when used with respect to an individual...

2013-07-01

384

34 CFR 303.25 - Native language.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Native language. 303.25 Section 303.25 Education ...Definitions Used in This Part § 303.25 Native language. (a) Native language, when used with respect to an individual...

2013-07-01

385

Hydrophobically Modified Polyacrylamide Block Copolymers for Fast, High-Resolution DNA Sequencing in Microfluidic Chips  

PubMed Central

By using a microfluidic electrophoresis platform to perform DNA sequencing, genomic information can be obtained more quickly and affordably than the currently employed capillary array electrophoresis (CAE) instruments. Previous research in our group has shown that physically cross-linked, hydrophobically modified polyacrylamide (HMPAM) matrices separate double-stranded DNA (dsDNA) more effectively than linear polyacrylamide (LPA) solutions. Expanding upon this work, we have synthesized a series of linear polyacrylamide-co-dihexylacrylamide (LPA-co-DHA) block copolymers specifically designed to electrophoretically sequence single-stranded DNA (ssDNA) quickly and efficiently on a microfluidic device. By incorporating very small amounts of N,N-dihexylacrylamide, a hydrophobic monomer, these copolymer solutions achieved up to ~10% increases in average DNA sequencing read length over LPA homopolymer solutions of matched molar mass. Additionally, the inclusion of the small amount of hydrophobe does not significantly increase the polymer solution viscosities, relative to LPA solutions, so that channel loading times between the copolymers and the homopolymers are similar. The resulting polymer solutions are capable of providing enhanced sequencing separations in a short period of time without compromising the ability to rapidly load and unload the matrix from a microfluidic device.

Forster, Ryan E.; Chiesl, Thomas N.; Fredlake, Christopher P.; White, Corin V.; Barron, Annelise E.

2012-01-01

386

Conceptual design, kinematics and dynamics of swimming robotic structures using ionic polymeric gel muscles  

NASA Astrophysics Data System (ADS)

The structural design, kinematics and swimming dynamics of autonomous swimming robotic structures which utilize an arrangement of electrically controlled ionic polymeric gel muscles are discussed. The general structural design of such swimming robotic structures is considered to be in the form of a submarine structure which is partially encapsulated in an elastic or flexible membrane filled with a counterionic electrolyte such as water+acetone. In such an encapsulated portion of the robotic swimming structure there exist specifically arranged polyacrylamide or PVA-AAA polymeric cylindrical fibres or bundles. The arrangement of, say, polyacrylamide fibres is such that it is capable of generating microprocessor-based electrically controlled propagating transverse waves to propel the partially encapsulated membrane structure in any direction and in any desired manner. A brief description of the governing equations is also presented.

Shahinpoor, M.

1992-03-01

387

Reversible self-assembly of gels through metal-ligand interactions  

PubMed Central

Metal-ligand interactions with various proteins form in vivo metal assemblies. In recent years, metallosupramolecular approaches have been utilized to forge an assortment of fascinating two- and three-dimensional nano-architectures, and macroscopic materials, such as metal-ligand coordination polymeric materials, have promise in artificial systems. However to the best of our knowledge, the self-assembly of macroscopic materials through metal-ligand interactions has yet to be reported. Herein we demonstrate a gel assembly formed via metal-ligand interactions using polyacrylamide modified with Fe-porphyrin and L-histidine moieties. The stress values for the assembly increase as the concentration of Fe-porphyrin or L-histidine in the gels increases. Moreover, agitation of Fe-porphyrin gel, Zn-porphyrin gel, and L-histidine gel in an 80?mM Tris-acetate buffer (pH 9.0) results in selective adhesion of the Fe-porphyrin gel to the L-histidine gel based on the affinities of Fe-porphyrin and Zn-porphyrin with L-histidine.

Kobayashi, Yuichiro; Takashima, Yoshinori; Hashidzume, Akihito; Yamaguchi, Hiroyasu; Harada, Akira

2013-01-01

388

In-phantom dosimetry for BNCT with Fricke and normoxic-polymer gels  

NASA Astrophysics Data System (ADS)

Measurements of in-phantom dose distributions and images are important for Boron Neutron Capture Therapy treatment planning. The method for spatial determination of absorbed doses in thermal or epithermal neutron fields, based on Fricke-xylenol-orange-infused gel dosimeters in form of layers, has revealed to be very reliable, as gel layer dosimeters give the possibility of obtaining spatial dose distributions and measurements of each dose contribution in neutron fields, by means of a properly studied procedure. Quite recently, BNCT has been applied to treat liver metastases; in this work the results of in-phantom dosimetry for explanted liver in BNCT treatments are described. Moreover, polyacrylamide gel (PAG) dosimeters in which a polymerization process appears as a consequence of absorbed dose, have been recently tested, because of their characteristic absence of diffusion. In fact, due to the diffusion of ferric ions, Fricke-gel dosimeters require prompt analysis after exposure to avoid spatial information loss. In this work the preliminary results of a study about the reliability of polymer gel in BNCT dosimetry are also discussed. Gel layers have been irradiated in a phantom exposed in the thermal column of the TRIGA MARK II reactor (Pavia). The results obtained with the two kinds of gel dosimeter have been compared.

Gambarini, G.; Agosteo, S.; Carrara, M.; Gay, S.; Mariani, M.; Pirola, L.; Vanossi, E.

2006-05-01

389

Synthesis of p -and n-type Gels Doped with Ionic Charge Carriers  

NASA Astrophysics Data System (ADS)

In this study, we synthesized the new kinds of semiconducting polymeric gels having negative ( n-type) and positive ( p-type) counter ions as charge carriers. The polyacrylamide gel was doped with pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid, trisodium salt), having {text{SO}}3^{ - } ions as side groups and Na+ as counter ions, so-called p-type semiconducting gel. The doping process was performed during the polymerization where the pyranine binds to the polymer strands over OH group chemically via radical addition. In a similar way, N-isopropylacrylamide (NIPA) gel was doped with methacrylamidopropyltrimethyl ammonium chloride (MAPTAC), having Cl- as counter ions, so-called n-type semiconducting gel. Here MAPTAC was embedded by copolymerization within the polymer network (NIPA). These semiconducting gels can show different electrical properties by changing the concentration of the doping agents, swelling ratio etc. We have shown that the pn junction, formed by combining p-type and n-type gels together in close contact, rectifies the current similar to the conventional Si and Ge diodes.

Alveroglu, E.; Yilmaz, Y.

2010-03-01

390

"Out-gel" tryptic digestion procedure for chemical cross-linking studies with mass spectrometric detection.  

PubMed

SDS-PAGE is one of the most powerful protein separation techniques, and in-gel digestion is the leading method for converting proteins separated by SDS-PAGE into peptides suitable for mass spectrometry-based proteomic studies. In in-gel digestion, proteins are digested within the gel matrix, and the resulting peptides are extracted into an appropriate buffer. Transfer of the digested peptides to the liquid phase for subsequent mass spectrometric analysis, however, may be hampered by peptide-specific characteristics, including size, shape, poor solubility, adsorption to the polyacrylamide, and-in the case of cross-linking applications-by the branched structure of the peptides produced. This can be a limitation in cross-linking studies where efficient recoveries of the cross-linked peptides are critical. To overcome this limitation, we have developed a modification to the standard in-gel digestion procedure for SDS-PAGE-separated cross-linked proteins, based on older passive diffusion methods. By omitting the gel staining and gel fixation steps, intact proteins or cross-linked protein complexes can move through the gel and into the buffer solution. Digestion of the entire protein in the buffer outside the gel increases the probability that most of the proteolytic peptides produced will be present in the final digest solution. The resulting peptide mixture is then freed of SDS and concentrated using SCX (strong cation exchange) zip-tips and analyzed by mass spectrometry. For standard protein identification studies and the recovery of noncross-linked peptides, the in-gel procedure outperformed the out-gel procedure, but for cross-linking studies with enrichable cross-linkers (such as CBDPS), the standard out-gel procedure allowed the recoveries of cross-links not recovered via the in-gel method. Labeling experiments showed that, with an enrichable cross-linker, 93% of the cross-links showed better or equal recoveries with the out-gel procedure, as compared to the in-gel procedure. It should be noted that this method is not designed to replace in-gel digestion for most proteomics applications. However, by using the out-gel method, we were able to detect twice as many interprotein CBDPS cross-links from the histone H2A/H2B complex as were found in the in-gel digested sample. PMID:24354799

Petrotchenko, Evgeniy V; Serpa, Jason J; Cabecinha, Ashley N; Lesperance, Mary; Borchers, Christoph H

2014-02-01

391

Fabrication of 3D-networks of native starch and their application to produce porous inorganic oxide networks through a supercritical route  

Microsoft Academic Search

Herein an effective method for fabrication of three dimensional networks of starch is presented. In this method, the native starch was dissolved in hot water to form solution, resulting in the formation of starch gel after cooled to room temperature. Then the water in the starch gel was exchanged by ethanol, followed by drying with supercritical (SC) CO2 extraction, the

Zhenjiang Miao; Kunlun Ding; Tianbin Wu; Zhimin Liu; Buxing Han; Guimin An; Shiding Miao; Guanying Yang

2008-01-01

392

Periodic mesoporous silica gels  

SciTech Connect

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.

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

1996-06-01

393

Electrophoresis and Gel Analysis  

NSDL National Science Digital Library

In this animation produced by WGBH and Digizyme, Inc., see how molecules of DNA are separated using gel electrophoresis, and how this process enables scientists to compare the molecular variations of two or more DNA samples.

Foundation, Wgbh E.

2011-09-22

394

Quantitation of Acrylamide (and Polyacrylamide): Critical Review of Methods for Trace Determination/Formulation Analysis and Future-Research Recommendations.  

National Technical Information Service (NTIS)

Polyacrylamides (esp. polyelectrolytes) have gained wide usage in water treatment (as flocculants/coagulants), tertiary oil recovery, and various other applications such as sewer grouts. Unreacted, residual acrylamide monomer (2-propenamide: CH2=CH-C(=O)-...

C. G. Daughton

1988-01-01

395

Two-dimensional gel electrophoresis image registration using block-matching techniques and deformation models.  

PubMed

Block-matching techniques have been widely used in the task of estimating displacement in medical images, and they represent the best approach in scenes with deformable structures such as tissues, fluids, and gels. In this article, a new iterative block-matching technique-based on successive deformation, search, fitting, filtering, and interpolation stages-is proposed to measure elastic displacements in two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) images. The proposed technique uses different deformation models in the task of correlating proteins in real 2D electrophoresis gel images, obtaining an accuracy of 96.6% and improving the results obtained with other techniques. This technique represents a general solution, being easy to adapt to different 2D deformable cases and providing an experimental reference for block-matching algorithms. PMID:24613260

Rodriguez, Alvaro; Fernandez-Lozano, Carlos; Dorado, Julian; Rabuñal, Juan R

2014-06-01

396

Colored pI standards and gel isoelectric focusing in strongly acidic pH.  

PubMed

Colored, low molecular weight pI markers have been developed for isoelectric focusing (IEF) in acidic pH range. Their isoelectric points (pIs) were determined by direct measurement of the pH of the focused bands after completion of IEF on polyacrylamide gels. The practicable suitability of the proposed pI markers as pI standards for IEF was tested by applying gel IEF. The acidic pH gradient was created either by commercial synthetic carrier ampholytes or by mixture of simple buffers consisting of acids (non-ampholytes) and ampholytic buffers. By applying simple acids, it was possible to extend the acidic pH range beyond those achievable with commercial synthetic carrier ampholytes. By using an experimental arrangement without electrode electrolyte reservoirs with electrodes creating the fixed end of the gel, the strongly acidic pH gradient was stable even for prolonged focusing time. PMID:15900453

Stastná, Miroslava; Slais, Karel

2005-05-01

397

Effects of Gel Thickness on Microscopic Indentation Measurements of Gel Modulus  

PubMed Central

In vitro, animal cells are mostly cultured on a gel substrate. It was recently shown that substrate stiffness affects cellular behaviors in a significant way, including adhesion, differentiation, and migration. Therefore, an accurate method is needed to characterize the modulus of the substrate. In situ microscopic measurements of the gel substrate modulus are based on Hertz contact mechanics, where Young's modulus is derived from the indentation force and displacement measurements. In Hertz theory, the substrate is modeled as a linear elastic half-space with an infinite depth, whereas in practice, the thickness of the substrate, h, can be comparable to the contact radius and other relevant dimensions such as the radius of the indenter or steel ball, R. As a result, measurements based on Hertz theory overestimate the Young's modulus. In this work, we discuss the limitations of Hertz theory and then modify it, taking into consideration the nonlinearity of the material and large deformation using a finite-element method. We present our results in a simple correction factor, ?, the ratio of the corrected Young's modulus and the Hertz modulus in the parameter regime of ?/h ? min (0.6, R/h) and 0.3 ? R/h ? 12.7. The ? factor depends on two dimensionless parameters, R/h and ?/h (where ? is the indentation depth), both of which are easily accessible to experiments. This correction factor agrees with experimental observations obtained with the use of polyacrylamide gel and a microsphere indentation method in the parameter range of 0.1 ? ?/h ? 0.4 and 0.3 ? R/h ? 6.2. The effect of adhesion on the use of Hertz theory for small indentation depth is also discussed.

Long, Rong; Hall, Matthew S.; Wu, Mingming; Hui, Chung-Yuen

2011-01-01

398

for Non-Native Teachers  

ERIC Educational Resources Information Center

work for, are often disconnected from the language, culture, and approaches to learning that facilitate Native students' achievement in school (Deyhle & Swisher, 1997; Klug & Hall, 2002; Lomawaima, 2001; Pewewardy, 2002; Reyhner & Jacobs, 2002; Tharp,…

Williams, Sharon Vegh

2013-01-01

399

Synthetic tracheal mucus with native rheological and surface tension properties.  

PubMed

In this study, the development of a model tracheal mucus with chemical composition and physical properties (bulk viscoelasticity and surface tension) matched to that of native tracheal mucus is described. The mucus mimetics (MMs) were formulated using components that are abundant in tracheal mucus (glycoproteins, proteins, lipids, ions, and water) at concentrations similar to those found natively. Pure solutions were unable to achieve the gel behavior observed with native mucus. The addition of a bifunctional cross-linking agent enabled control over the viscoelastic properties of the MMs by tailoring the concentration of the cross-linking agent and the duration of cross-linking. Three MM formulations with different bulk viscoelastic properties, all within the normal range for nondiseased tracheal mucus, were chosen for investigation of surfactant spreading at the air-mimetic interface. Surfactant spread quickly and completely on the least viscoelastic mimetic surface, enabling the surface tension of the mimetic to be lowered to match native tracheal mucus. However, surfactant spreading on the more viscoelastic mimetics was hindered, suggesting that the bulk properties of the mimetics dictate the range of surface properties that can be achieved. PMID:23813841

Hamed, R; Fiegel, J

2014-06-01

400

Mechanochromic photonic gels.  

PubMed

Polymer gels are remarkable materials with physical structures that can adapt significantly and quite rapidly with changes in the local environment, such as temperature, light intensity, electrochemistry, and mechanical force. An interesting phenomenon observed in certain polymer gel systems is mechanochromism - a change in color due to a mechanical deformation. Mechanochromic photonic gels are periodically structured gels engineered with a photonic stopband that can be tuned by mechanical forces to reflect specific colors. These materials have potential as mechanochromic sensors because both the mechanical and optical properties are highly tailorable via incorporation of diluents, solvents, nanoparticles, or polymers, or the application of stimuli such as temperature, pH, or electric or strain fields. Recent advances in photonic gels that display strain-dependent optical properties are discussed. In particular, this discussion focuses primarily on polymer-based photonic gels that are directly or indirectly fabricated via self-assembly, as these materials are promising soft material platforms for scalable mechanochromic sensors. PMID:23754505

Chan, Edwin P; Walish, Joseph J; Urbas, Augustine M; Thomas, Edwin L

2013-08-01

401

Polymer gel dosimetry.  

PubMed

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

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

2010-03-01

402

Rheological Properties of Starch and Whey Protein Isolate Gels  

Microsoft Academic Search

The paste viscosity of starches Amioca (~0.5% amylose), native corn (~27% amylose), Hylon VII (~70% amylose), tapioca (~19% amylose), and their whey protein isolate (WPI; 50\\/50) mixtures at varying solid concentration of 2.5, 5, 10, 15 and 20% were determined. At higher gel concentration (20%) during the cooling cycle, WPI paste measured by rapid visco-analyser (RVA) showed a tremendous increase

C. W. P. Carvalho; C. I. Onwulata; P. M. Tomasula

2007-01-01

403

Chemical in-gel deglycosylation of O-glycoproteins improves their staining and mass spectrometric identification.  

PubMed

Heavily O-glycosylated membrane-tethered or secreted proteins often escape identification by gel-based proteomics due to weak staining and low identification rates in MS/MS. The present protocol refers to a chemical in-gel de-O-glycosylation of proteins based on repeated oxidation/elimination of glycans leaving the protein backbone intact at the gel position of the native glycoprotein. On restaining prior to spot picking, the deglycosylated proteins are detectable at increased staining intensities when applying fluorescent dyes or silver stains. Evidence shows that de-O-glycosylation of proteins in gels is efficient and does not introduce structural artifacts into the protein backbones. In-gel trypsin digestion of deglycosylated proteins, such as human glycophorin A, revealed strongly enhanced sequence coverage in LC-ESI MS/MS. The protocol is applicable in 1D and 2D gel settings within one working day. PMID:23580477

Bellwied, Petra; Staubach, Simon; Hanisch, Franz-Georg

2013-08-01

404

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

PubMed

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

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

1999-06-01

405

Analysis of Inorganic Polyphosphates by Capillary Gel Electrophoresis  

PubMed Central

This paper describes the development of a method that uses Capillary Gel Electrophoresis (CGE) to analyze mixtures of inorganic polyphosphate ((Pi)n). Resolution of (Pi)n on the basis of n, the number of residues of dehydrated phosphate, is accomplished by CGE using capillaries filled with solutions of poly(N,N-dimethylacrylamide) (PDMA) and indirect detection by the UV-absorbance of a chromophore, terephthalate, added to the running buffer. The method is capable of resolving peaks representing (Pi)n with n up to ~70; preparation and use of authentic standards enables the identification of peaks for (Pi)n with n = 1 - 10. The main advantages of this method over previously reported methods for analyzing mixtures of (Pi)n (e.g., gel electrophoresis, CGE using polyacrylamide-filled capillaries) are its resolution, convenience, and reproducibility; gel-filled capillaries are easily regenerated by pumping in fresh, low-viscosity solutions of PDMA. The resolution is comparable to that of ion-exchange chromatography and detection of (Pi)n by suppressed conductivity. The method is useful for analyzing (Pi)n generated by the dehydration of Pi at low temperature (125 - 140 °C) with urea, in a reaction that may have been important in prebiotic chemistry. The method should also be useful for characterizing mixtures of other anionic, oligomeric or polymeric species without an intrinsic chromophore (e.g., sulfated polysaccharides, oligomeric phospho-diesters).

Lee, Andrew; Whitesides, George M.

2010-01-01

406

Radiation dose distribution in polymer gels by Raman spectroscopy.  

PubMed

The Raman spectroscopy of polymer gel dosimeters has been investigated with a view to developing a novel dosimetry technique that is capable of determining radiation dose within a micrometer of spatial resolution. The polymer gel dosimeter, known as the PAG dosimeter, is typically made up of acrylamide, N,N'-methylene-bis--acrylamide, gelatin, and water. A polyacrylamide network within the gelatin matrix forms in response to an absorbed dose. The loss of monomers may be monitored by corresponding changes to the Raman spectrum. Principal component analysis offers a simple method of quantifying the absorbed radiation dose from the Raman spectrum of the polymer gel. The background luminescence in the spectrum increased significantly with dose and is shown to originate in the glass of the sample vial. The competing effects of elastic scatter, which increases with dose due to the formation of polymer, and sample absorption were quantified and found to introduce errors of up to 5% under certain conditions. Raman spectra as a function of distance from the air-surface interface have been measured for samples that were subjected to doses delivered by a clinical linear accelerator. The depth dose profile thus obtained compared favorably with "gold standard" ion-chamber measurements. PMID:14610936

Rintoul, L; Lepage, M; Baldock, C

2003-01-01

407

CONFORMANCE IMPROVEMENT USING GELS  

SciTech Connect

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

Randall S. Seright

2002-02-28

408

Native American Healing Practices and Counseling  

ERIC Educational Resources Information Center

An experiential Native American healing practices course, co-taught by a Native American pastoral counselor and a counselor educator, was offered to graduate counseling students to help them better understand Native American worldviews. A student participant's reflections are included. Students attended Native American ceremonies and learned…

Rybak, Christopher J.; Eastin, Carol Lakota; Robbins, Irma

2004-01-01

409

The Problems with Native American Mascots.  

ERIC Educational Resources Information Center

Lays out the main arguments against the use of Native American mascots, including that mascots represent racist stereotypes of Native Americans; the stereotypes focus on the past and obscure the lives of contemporary Native Americans; mascots misrepresent, distort, and trivialize many aspects of Native American culture; and mascot stereotypes have…

Davis, Laurel R.

2002-01-01

410

Use of Polyacrylamide to Reduce Seepage From Unlined Irrigation Canals: Initial Results From Small Scale Test Troughs  

NASA Astrophysics Data System (ADS)

Polyacrylamide (PAM) is a class of long-chain synthetic polymers that are used extensively in food packaging, paper manufacturing, wastewater treatment, and as a soil amendment to reduce erosion. Recent empirical evidence has shown that applying linear, anionic PAM seepage can also reduce seepage from unlined irrigation canals. A diverse set of experiments has been initiated to understand the efficacy of PAM usage in ditch environments. The experiments span multiple scales, from small-scale bench top and artificial furrow experiments, to larger engineered furrows and irrigation ditches. Our objective was to assess the effectiveness of different PAM application methods and concentrations on seepage reductions in small scale, artificial Test Troughs (TT). The TT consists of two 24 m long, 10 cm deep furrows formed from native ASTM C-33 sand. During water application, inflows, outflows, and seepage from under the furrows were continuously measured. PAM in either granular or partially hydrated form was applied at various rates. The results presented here cover one facet of the research program. The application of granular PAM to the TT reduced seepage from 49 L/min to less than 22 L/min, depending on treatment. A PAM application rate of 44 kg/(canal ha) reduced seepage by 69+/-9 percent, and was more effective than an application rate of 11 kg/(canal ha) that reduced seepage by 56+/-22 percent. Seepage reduction was calculated using flow rates between 400 and 600 elapsed minutes. Inclusion of later data (up to 1440 min) into seepage calculations was complicated by a reduction in seepage at the control trough caused either by a reduction in head or deposition of suspended sediment. We hypothesize that the PAM-sediment layer present in the treated trough exerted a greater control on seepage than sediment deposition alone. However, heavy suspended sediment loads associated with hydrologic events reduced seepage rates within both the control and treated troughs, somewhat masking the effects of the PAM. The application of linear, anionic PAM to the artificial Test Troughs did significantly reduce seepage rates. Additional work will be necessary to scale these results up to larger ditches, and to assess if the seepage reduction occurring by suspended sediment deposition is an artifact of this small scale experiment.

Susfalk, R. B.; Young, M. H.; Schmidt, M.; Epstein, B. J.; Goreham, J.; Swhihart, J.; Smith, D.

2005-12-01

411

Polymer gel dosimetry technique  

SciTech Connect

Recent advances in radiation therapy techniques, including non-coplanar beams, dynamic wedge, multi-leaf collimator, sterotactic radiosurgery, high-dose-rate brachytherapy using remote afterloading and shielded applicators, and heavy-particle beams such as protons, have created a need for three-dimensional, tissue-equivalent dosimeters, capable of recording time-integrated dose distributions with high spatial resolution and accuracy, and independent of energy and dose rate. All these requirements are met by the recently developed polymer gel dosimetry technique, based on radiation induced formation of polymer microparticles in a tissue-equivalent gel. A permanent image of the dose distribution is encoded in the gel as the distribution of its optical turbidity and of the NMR relaxation rates of the water protons in the gel. Three dimensional dose distributions can be measured using magnetic resonance imaging or optical transmission tomography. The prototype gel, called BANG{trademark}, is now being tested at several hospital sites throughout the U.S. and Europe.

Maryanski, M.J.

1995-12-31

412

Controlling tailwater sediment and phosphorus concentrations with polyacrylamide in the Imperial Valley, California.  

PubMed

External loading of phosphorus (P) from agricultural surface discharge (tailwater) is the main cause of excessive algae growth and the eutrophication of the Salton Sea, California. Continuous polyacrylamide (PAM) applications to agricultural irrigation water inflows were evaluated as a means of reducing sediment and P in tailwater. Zero (control) and 1 mg L(-1) PAM (PAM1) treatments were compared at 17 Imperial Valley field sites. Five and 10 mg L(-1) PAM treatments (PAM5, PAM10) were conducted at one site. The particulate phosphorus (Pp) fraction was determined as the difference between total phosphorus (Pt) and the soluble phosphorus (Ps) fraction. We observed 73, 82, and 98% turbidity reduction with PAM1, PAM5, and PAM10 treatments. Although eight field sites had control tailwater sediment concentrations above the New River total maximum daily loads (TMDL), all but one were made compliant during their paired PAM1 treatments. While PAM1 and PAM10 reduced tail water Pp by 31 and 78%, none of the treatments tested reduced Ps. This may have been caused by high irrigation water Na concentrations which would reduce Ca adsorption and Ca-phosphate bridging on the PAM. The PAM1 treatments resulted in <0.5 mg L(-1) drain water polyacrylamide concentrations 1.6 km downstream of PAM addition, while PAM5 and PAM10 treatments produced > 2 mg L(-1) drain water polyacrylamide concentrations. We concluded that, although PAM practically eliminates Imperial Valley tailwater sediment loads, it does not effectively reduce tailwater Ps, the P fraction most responsible for the eutrophication of the Salton Sea. PMID:16738392

Goodson, Christopher C; Schwartz, Gregory; Amrhein, Christopher

2006-01-01

413

Polyacrylamide-hydroxyapatite composite: Preparation, characterization and adsorptive features for uranium and thorium  

SciTech Connect

The composite of synthetically produced hydroxyapatite (HAP) and polyacrylamide was prepared (PAAm-HAP) and characterized by BET, FT-IR, TGA, XRD, SEM and PZC analysis. The adsorptive features of HAP and PAAm-HAP were compared for UO{sub 2}{sup 2+} and Th{sup 4+}. The entrapment of HAP into PAAm-HAP did not change the structure of HAP. Both structures had high affinity to the studied ions. The adsorption capacity of PAAm-HAP was than that of HAP. The adsorption dependence on pH and ionic intensity provided supportive evidences for the effect of complex formation on adsorption process. The adsorption kinetics was well compatible to pseudo second order model. The values of enthalpy and entropy changes were positive. Th{sup 4+} adsorption from the leachate obtained from a regional fluorite rock confirmed the selectivity of PAAm-HAP for this ion. In consequence, PAAm-HAP should be considered amongst favorite adsorbents for especially deposition of nuclear waste containing U and Th, and radionuclide at secular equilibrium with these elements. - Graphical abstract: SEM images of hydroxyapatite (HAP) and polyacrylamide-hydroxyapatite (PAAm-HAP), and the adsorption isotherms for Uranium and Thorium. Highlights: Black-Right-Pointing-Pointer Composite of PAAm-HAP was synthesized from hydroxyapatite and polyacrylamide. Black-Right-Pointing-Pointer The materials were characterized by BET, FT-IR, XRD, SEM, TGA and PZC analysis. Black-Right-Pointing-Pointer HAP and PAAm-HAP had high sorption capacity and very rapid uptake for UO{sub 2}{sup 2+} and Th{sup 4+}. Black-Right-Pointing-Pointer Super porous PAAm was obtained from PAAm-HAP after its removal of HAP content. Black-Right-Pointing-Pointer The composite is potential for deposition of U, Th and its associate radionuclides.

Baybas, Demet, E-mail: dbaybas@cumhuriyet.edu.tr [Cumhuriyet University, Faculty of Science, Department of Chemistry, Kayseri, Sivas 58140 (Turkey)] [Cumhuriyet University, Faculty of Science, Department of Chemistry, Kayseri, Sivas 58140 (Turkey); Ulusoy, Ulvi, E-mail: ulusoy@cumhuriyet.edu.tr [Cumhuriyet University, Faculty of Science, Department of Chemistry, Kayseri, Sivas 58140 (Turkey)] [Cumhuriyet University, Faculty of Science, Department of Chemistry, Kayseri, Sivas 58140 (Turkey)

2012-10-15

414

Nanocomposite polyacrylamide based open cavity fiber Fabry-Perot humidity sensor.  

PubMed

A humidity sensor with a low temperature sensitivity is proposed and demonstrated by coating a nanocomposite hygrometer polyacrylamide in an open interferometric cavity of a fiber Fabry-Perot interferometer. In this paper the Fabry-Perot structure is formed by splicing one short section of single mode fiber between two sections of single mode fiber with a larger offset fusing method. Experimental results show that relative humidity (RH) sensitivity of the sensor is ?0.1 nm/(1% RH) in the range of 38% to 78% RH and ?5.868 nm/(1%RH) in the range of 88% to 98% RH, respectively. PMID:23128715

Yao, Jun; Zhu, Tao; Duan, De-Wen; Deng, Ming

2012-11-01

415

Preparation, characterization and microhardness study of semi interpenetrating polymer networks of polyvinyl alcohol and crosslinked polyacrylamide.  

PubMed

Semi-IPNs based on polyvinyl alcohol (PVA) and crosslinked polyacrylamide (PAM) were prepared and characterized. Various compositions of semi-interpenetrating polymer networks (semi-IPNs) were prepared by varying concentrations of PVA, acrylamide (AM) and crosslinker N,N'-methylene bis acrylamide (MBA) in the feed mixtures and polymerized using a suitable redox system comprising of potassium persulphate and metabisulphite. The prepared semi-IPNs were characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD) methods. The prepared semi-IPNs were also investigated for microhardness measurements. PMID:17143762

Mishra, Shefali; Bajpai, R; Katare, R; Bajpai, A K

2006-12-01

416

Effects of polyacrylamide, biopolymer, and biochar on decomposition of soil organic matter and 14C-labeled plant residues as determined by enzyme activities  

NASA Astrophysics Data System (ADS)

Application of polymers for the improvement of aggregate structure and reduction of soil erosion may alter the availability and decomposition of plant residues. In this study, we assessed the effects of anionic polyacrylamide (PAM), synthesized biopolymer (BP), and biochar (BC) on the decomposition of 14C-labeled maize residue in sandy and sandy loam soils. Specifically, PAM and BP with or without 14C-labeled plant residue were applied at 400 kg ha-1, whereas BC was applied at 5000 kg ha-1, after which the soils were incubated for 80 days at 22 oC. Initially, plant residue decomposition was much higher in untreated sandy loam soil than in sandy soil. Nevertheless, the stimulating effects of BP and BC on the decomposition of plant residue were more pronounced in sandy soil, where it accounted for 13.4% and 23.4% of 14C input, respectively, whereas in sandy loam soil, the acceleration of plant residue decomposition by BP and BC did not exceed 2.6% and 14.1%, respectively, compared to untreated soil with plant residue. The stimulating effects of BP and BC on the decomposition of plant residue were confirmed based on activities of ?-cellobiohydrolase, ?-glucosidase, and chitinase in both soils. In contrast to BC and BP, PAM did not increase the decomposition of native or added C in both soils.

Mahmoud Awad, Yasser; Ok, Young Sik; Kuzyakov, Yakov

2014-05-01

417

Patterns in shrinking gels  

NASA Astrophysics Data System (ADS)

POLYMER gels can undergo a volume phase transition (either continuous or discontinuous) when an external condition, such as temperature or solvent composition, is altered1-3. During this transition, the volume may change by a factor of several thousand, and various patterns develop in the gel. The patterns arising from swelling and shrinking differ in both their appearance and their physical mechanisms. The mechanism for the formation and evolution of patterns on swelling gels has been established as being due to a single kind of mechanical instability4-7 in contrast, the shrinking patterns seem to be sensitive to both the initial and final states of the transition. Here we classify the various shrinking patterns in the form of a phase diagram, and explain the poly-morphism in terms of macroscopic phase separation.

Matsuo, Eriko Sato; Tanaka, Toyoichi

1992-08-01

418

Gel-silica science  

SciTech Connect

Sol-gel techniques can be used to produce two new types of optical silicas, termed Type V for the full density material and Type VI for the optically transparent porous material. This paper summarizes the processing differences between these six types of commercial silicas. The primary emphasis of this paper is to discuss the scientific basis for the processing of Types V and VI optical silica. First, however, the use of sol-gel processing of other systems will be briefly reviewed. The controlled hydrolysis of alkoxides has also been used to produce submicrometer TiO{sub 2}, doped TiO{sub 2} (17), ZrO{sub 2} (18), doped ZrO{sub 2} (18), doped SiO{sub 2} (19), SrTiO{sub 3} (20), and corderite (20) powders. Emulsions have been employed to produce spherical powders of mixed cation oxides, such as yttrium aluminum garnets (YAG) and many other systems (20). Sol-gel powder processes have also been applied to fissile elements (21) where spray form sols UO{sub 2}, and rigid gel spheres of UO-PuO{sub 2} are formed during passage through a column of heated liquid. Both crystalline and vitreous ceramic fibers have been prepared using the sol-gel method. Compositions include TiO{sub 2}-SiO{sub 2} and ZrO{sub 2}-SiO{sub 2} glass fibers (22), high purity SiO{sub 2} waveguide fibers (23), Al{sub 2}O{sub 3}, ZrO{sub 2}, ThO{sub 2}, MgO, TiO{sub 2}, ZrSiO{sub 4}, 3AlO{sub 3}-2SiO{sub 2} fibers (24). Sol-gel derived alumina grains are important commercial products (25).

Hench, L.L.; Vasconcelos, W. (Advanced Materials Research Center, Univ. of Florida, Gainesville, FL (US))

1990-01-01

419

Gel Electrophoresis of Dyes  

NSDL National Science Digital Library

In this experiment related to plant biotechnology, learners discover how to prepare and load an electrophoresis gel. They will then run the gels in an electrophoresis system to separate several dyes that are of different molecular sizes and carry different charges. This technique is fundamental to many of the procedures used in biotechnology. This lesson guide includes background information for the educator, safety precautions, and questions with answers for learners. For safety reasons, adult supervision is recommended. Modifications for use with younger learners are described in a related PDF (see related resource).

Stephens, Janice; Leach, Jan

2011-01-01

420

Swelling of Olympic Gels  

NASA Astrophysics Data System (ADS)

The swelling equilibrium of Olympic gels, which are composed of entangled cyclic polymers, is studied by Monte Carlo simulations. In contrast to chemically cross-linked polymer networks, we observe that Olympic gels made of chains with a larger degree of polymerization, N, exhibit a smaller equilibrium swelling degree, Q?N-0.28?0-0.72, at the same polymer volume fraction ?0 at network preparation. This observation is explained by a desinterspersion (reorganization with release of nontrapped entanglements) process of overlapping nonconcatenated rings upon swelling.

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

2014-06-01

421

Native Americans and the Environment  

NSDL National Science Digital Library

Created by anthropologist Dr. Alx V. Dark and sponsored by the Center for Conservation Biology at Rice University, this Website promotes the research and study of environmental issues facing Native American communities, particularly the politics of land and treaty rights. The site also explores the "values and historical experiences that Native Americans bring to bear on environmental issues." Native Americans and the Environment provides a bibliographic database, which covers topics such as environmental justice, natural resource utilization, land and treaty rights, and demography and migration. The database currently contains over 1,500 citations, and will be expanded to approximately 3,000 by the end of 1999. The site also includes an extensive directory of hundreds of annotated Internet resources organized by subject and geographic region. In addition, a case studies section is under development and will include environmental problems and their histories, current actions, or solutions; a list of related Internet resources; and a bibliography.

1999-01-01

422

Gel dependence of electrophoretic mobilities of double-stranded and viroid RNA and estimation of the contour length of a viroid by gel electrophoresis.  

PubMed

Double-stranded (ds) RNA normally exhibits a lower electrophoretic mobility than dsDNA having the same number of base pairs. This has been attributed to its net charge density that is lower than that of B-form DNA. But we show here that dsRNA runs faster than corresponding DNA in gels containing either > or = 2.5% agarose or > or = 8% acrylamide with high crosslinking (19:1 acrylamide:N,N'-methylenebisacrylamide). However, the relative mobility of dsRNA as compared with DNA, extrapolated to 0% gel (0%T), remains constant (0.90 +/- 0.03) in all systems, in support of the charge density hypothesis. In comparison to dsRNA standards, the potato spindle tuber viroid, a small approximately 70% base-paired rod-like pathogenic RNA, is strongly retarded, presumably because of greater flexibility and/or stable curvature. Depending on the gel system, nonlinear extrapolation to 0% T leads to an apparent contour length of 140-230 bp, whereas 130 +/- 20 bp can be determined from electron micrographs and 123-126 bp from secondary structure modeling. We attribute the variation of the electrophoretic behavior of both dsRNA and viroid RNA to interactions with the gel matrix. Nevertheless, extrapolation of the apparent contour length (in bp dsRNA) determined from low-crosslinked polyacrylamide gels (2.6%C) is comparable to the determination by alternative methods. PMID:7720685

Gast, F U; Sänger, H L

1994-12-01

423

A relational Fuzzy C-Means algorithm for detecting protein spots in two-dimensional gel images.  

PubMed

Two-dimensional polyacrylamide gel electrophoresis of proteins is a robust and reproducible technique. It is the most widely used separation tool in proteomics. Current efforts in the field are directed at the development of tools for expanding the range of proteins accessible with two-dimensional gels. Proteomics was built around the two-dimensional gel. The idea that multiple proteins can be analyzed in parallel grew from two-dimensional gel maps. Proteomics researchers needed to identify interested protein spots by examining the gel. This is time consuming, labor extensive and error prone. It is desired that the computer can analyze the proteins automatically by first detecting, then quantifying the protein spots in the 2D gel images. This paper focuses on the protein spot detection and segmentation of 2D gel electrophoresis images. We present a new technique for segmentation of 2D gel images using the Fuzzy C-Means (FCM) algorithm and matching spots using the notion of fuzzy relations. Through the experimental results, the new algorithm was found out to detect protein spots more accurately, then the current known algorithms. PMID:20865504

Rashwan, Shaheera; Faheem, Talaat; Sarhan, Amany; Youssef, Bayumy A B

2010-01-01

424

Peculiarities of diffusion in gels  

NASA Astrophysics Data System (ADS)

An optical method was applied to study the peculiarities of diffusion in gel: this method provides real-time visualization of spreading of solutes brought into the gel. It was shown that spectral characteristics of reflected light give additional information about nature of diffusive spreading of solutes and about state of the gel. Gels with different densities and lifetime were studied. These parameters have strong influence on the velocity of diffusion. The study demonstrated critical differences for diffusion process in gels with true solutions and with solutions with nanoparticles. Experiments discovered the anisotropy in 3D diffusion of solutes in gels; physical explanation of this phenomenon was proposed.

Pokusaev, B. G.; Karlov, S. P.; Vyazmin, A. V.; Nekrasov, D. A.

2013-12-01

425

Peculiarities of diffusion in gels  

NASA Astrophysics Data System (ADS)

An optical method was applied to study the peculiarities of diffusion in gel: this method provides real-time visualization of spreading of solutes brought into the gel. It was shown that spectral characteristics of reflected light give additional information about nature of diffusive spreading of solutes and about state of the gel. Gels with different densities and lifetime were studied. These parameters have strong influence on the velocity of diffusion. The study demonstrated critical differences for diffusion process in gels with true solutions and with solutions with nanoparticles. Experiments discovered the anisotropy in 3D diffusion of solutes in gels; physical explanation of this phenomenon was proposed.

Pokusaev, B. G.; Karlov, S. P.; Vyazmin, A. V.; Nekrasov, D. A.

2014-12-01

426

Denatured ricin can be detected as native ricin by immunological methods, but nontoxic in vivo.  

PubMed

Ricin is a glycoprotein from Ricinus communis seeds. It is known to have diverse toxic effects on cells of different visceral organs. In the present study, we purified and denatured ricin in a boiling water bath for different time intervals. We further made an attempt to identify native and denatured ricin by immunobased detection systems. All the antigen/antibody-based assays identified native and denatured ricin. On SDS-PAGE, only native ricin was observed. In western blotting, ricin boiled for 3.75 min gave a strong band on X-ray film. On native polyacryl amide gel electrophoresis, native and denatured ricin gave ricin band in 60-kDa region. The denatured ricin did not [corrected] cause mortality up to 25 mg/kg, while 5 and 10 microg/kg of native ricin caused 50% and 100% mortality, respectively. Detection of native and denatured ricin is very difficult, and the investigating agencies, forensic scientists, and analysts should be very careful while interpreting the results. PMID:20102466

Kumar, Om; Pradhan, Santwana; Sehgal, Payal; Singh, Yamini; Vijayaraghavan, Rajagopalan

2010-05-01

427

Preparation of Homogeneous Aluminosilicate Gels by Sol/Gel Techniques.  

National Technical Information Service (NTIS)

The factors affecting the production of homogeneous aluminosilicate gels from alkoxide precursors were investigated. Aluminosilicate gels were made in acidic conditions with a prepolymerization of the silicate precursors followed by the addition of the al...

M. Reese J. Sanchez A. V. McCormick

1993-01-01

428

Discrete film thickness in polyacrylamide-CdS nanocomposite ultrathin films  

SciTech Connect

A nanocomposite of polyacrylamide, a water soluble polymer, and nanocrystalline CdS has been prepared using a chemical route. Transmission electron microscope observation shows that the particles are attached via the polymer coils. The reduction of viscosity for the composite, despite the increase in concentration, indicates a reduction of interchain entanglement between the composite coils. Ultrathin films were prepared from the nanocomposite and pure polyacrylamide using spin coating on a Si(100) substrate in the speed range of 500 to 5000 rpm. X-ray reflectivity studies of the pure polymer and composite films were carried out in vacuum. The thickness of the composite films varies nonmonotonically with spinning speed and is found to lie in discrete 'bands' of thickness separated by 'forbidden regions'. The power law behavior of the thickness with the spinning speed was also found to be different for the composite films in comparison to the polymer ones. A model has been proposed in terms of discrete numbers of layers composed of CdS-attached polymer coils to explain the phenomena.

Singh, Amarjeet; Mukherjee, M. [Surface Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata-700064 (India)

2004-11-01

429

Electrically controlled release of salicylic acid from poly(p-phenylene vinylene)/polyacrylamide hydrogels.  

PubMed

The apparent diffusion coefficients, Dapp, and the release mechanisms of salicylic acid from salicylic acid-loaded polyacrylamide hydrogels, SA-loaded PAAM, and salicylic acid-doped poly(phenylene vinylene)/polyacrylamide hydrogels, SA-doped PPV/PAAM, were investigated. In the absence of an electric field, the diffusion of SA from the SA-doped PPV/PAAM is delayed in the first 3 h due to the ionic interaction between the anionic drug (SA anion) and the PPV. Beyond this period, SA is dissolved in and can diffuse into the buffer solution through the PAAM matrix. The Dapp of the SA-doped PPV/PAAM is higher than that of the SA-loaded PAAM, and the former increases with increasing electric field strength due to combined mechanisms: the expansion of PPV chains inside the hydrogel; the reduction reaction under a negative potential driving the anionic SA through the PAAM matrix; and the expansion of the matrix pore. The Dapp of SA from the SA-loaded PAAM and the SA-doped PPV/PAAM apparently obey the scaling behavior: Dapp/D0 = (drug size/pore size)m with the scaling exponent m equal to 0.50 at 0.1 V for both SA-loaded PAAM and SA-doped PPV/PAAM. Thus, the presence of the conductive polymer and the applied electric field can be combined to control the drug release rate at an optimal desired level. PMID:19162150

Niamlang, Sumonman; Sirivat, Anuvat

2009-04-17

430

Hydrolyzed polyacrylamide grafted carboxymethylxyloglucan based microbeads for pH responsive drug delivery.  

PubMed

The present study investigates the pharmaceutical application of hydrolyzed polyacrylamide grafted carboxymethylxyloglucan (HPam-g-CMXG), as promising polymeric material for the development of pH responsive microbeads. The graft copolymer was synthesized by conventional free radical polymerization method and saponified to enhance its functionality and characterized. An acute oral toxicity study ensured the bio-safety of developed copolymer for clinical application. Various batches of pH responsive spherical microbeads were developed and evaluated for the effect of process parameters on their overall performance. Result of in vitro drug release study (USP Type-II, paddle method) carried out in two different pH media (pH 1.2 and pH 7.4) showed a triphasic drug release pattern in all the formulations. Both the drug release and swelling of microbeads were significantly higher in simulated intestinal (alkaline) pH compared to simulated gastric (acidic) pH and this nature is desirable for targeted drug delivery. A strong correlation was observed between the process parameters and matrix composition and it directly influenced the drug transport mechanism. In conclusion, the hydrolyzed polyacrylamide grafted carboxymethylxyloglucan holds an immense potential to be explored pharmaceutically as new matrix material for the design of targeted drug delivery system. PMID:24632345

Setty, C Mallikarjuna; Deshmukh, Anand S; Badiger, Aravind M

2014-06-01

431

Aptamers embedded in polyacrylamide nanoparticles: a tool for in vivo metabolite sensing.  

PubMed

We describe a new type of aptamer-based optical nanosensor which uses the embedding of target responsive oligonucleotides in porous polyacrylamide nanoparticles to eliminate nuclease instability. The latter is a common problem in the use of aptamer sensors in biological environments. These aptamers embedded in nanoparticles (AptaNPs) are proposed as a tool in real-time metabolite measurements in living cells. The AptaNPs comprise 30 nm polyacrylamide nanoparticles, prepared by inverse microemulsion polymerization, which contain water-soluble aptamer switch probes (ASPs) trapped in the porous matrix of the nanoparticles. The matrix acts as a molecular fence allowing rapid diffusion of small metabolites into the particles to interact with the aptamer molecules, but at the same time it retains the larger aptamer molecules inside the nanoparticles providing protection against intracellular degradation. We tested the ability of the AptaNPs to measure the adenine-nucleotide content in yeast cells. Our results successfully demonstrate the potential for monitoring any metabolite of interest in living cells by selecting specific aptamers and embedding them in nanoparticles. PMID:20731422

Nielsen, Lise J; Olsen, Lars F; Ozalp, Veli C

2010-08-24

432

Calcium tartrate gel.  

PubMed

A method for preparation of a gel for chromatography has been developed. The adsorbent is calcium tartrate treated with potassium phosphate. By changing the temperature of synthesis (10-65 degrees C) and concentration of the salts (calcium chloride and sodium potassium tartrate) from 0.3 to 3.0 M, we have been able to prepare adsorbent crystals of definite sizes in the range 35-200 microns. In all cases, for synthesis of adsorbent, the Ca2+/K+Na+ ratio was greater than 1. After treatment of calcium tartrate crystals with 0.075-1.5 M potassium phosphate at 80-100 degrees C and pH 8.5-9.0, an appropriate chromatographic adsorbent was prepared. The chromatographic properties of calcium tartrate gel have been studied. The adsorbent permits flow rates of 25-150 ml/h, depending on the particle size. The capacity of calcium tartrate gel for binding BSA, RNA, and DNA was similar to that of Tiselius' hydroxyapatite (A. Tiselius, S. Hjerten, O. Levin (1956) Arch. Biochem. Biophys. 65, 132-155). The spheric shape of gel particles permits uniform and compact packing of adsorbent under the conditions of column chromatography. PMID:2757203

Akhrem, A A; Drozhdenyuk, A P

1989-05-15

433

Non-native grass invasion alters native plant composition in experimental communities  

Microsoft Academic Search

Invasions of non-native species are considered to have significant impacts on native species, but few studies have quantified\\u000a the direct effects of invasions on native community structure and composition. Many studies on the effects of invasions fail\\u000a to distinguish between (1) differential responses of native and non-native species to environmental conditions, and (2) direct\\u000a impacts of invasions on native communities.

S. Luke Flory; Keith Clay

2010-01-01

434

Effects of non-native plants on the native insect community of Delaware  

Microsoft Academic Search

Due to the lack of a co-evolutionary history, the novel defenses presented by introduced plants may be insurmountable to many\\u000a native insects. Accordingly, non-native plants are expected to support less insect biomass than native plants. Further, native\\u000a insect specialists may be more affected by introduced plants than native generalist herbivores, resulting in decreased insect\\u000a diversity on non-native plants due to

Marion E. Zuefle; William P. Brown; Douglas W. Tallamy

2008-01-01

435

Enzymatic assessment of cholesterol on electrophoresis gels for estimating HDL size distribution and plasma concentrations of HDL subclasses[S  

PubMed Central

The aim of this study was to develop an enzymatic cholesterol staining method to determine HDL subclasses in a polyacrylamide gradient gel electrophoresis, which further allows staining by protein in the same electrophoresis lane. HDLs from 120 healthy individuals were separated through nondenaturing PAGE. HDLs were stained for cholesterol using an enzymatic semisolid mixture. Once the gels were unstained, they were stained again for proteins with Coo