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1

Functional Characterization of Reductive Dehalogenases by Using Blue Native Polyacrylamide Gel Electrophoresis  

PubMed Central

Dehalococcoides mccartyi strains are obligate organohalide-respiring bacteria harboring multiple distinct reductive dehalogenase (RDase) genes within their genomes. A major challenge is to identify substrates for the enzymes encoded by these RDase genes. We demonstrate an approach that involves blue native polyacrylamide gel electrophoresis (BN-PAGE) followed by enzyme activity assays with gel slices and subsequent identification of proteins in gel slices using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). RDase expression was investigated in cultures of Dehalococcoides mccartyi strain BAV1 and in the KB-1 consortium growing on chlorinated ethenes and 1,2-dichloroethane. In cultures of strain BAV1, BvcA was the only RDase detected, revealing that this enzyme catalyzes the dechlorination not only of vinyl chloride, but also of all dichloroethene isomers and 1,2-dichloroethane. In cultures of consortium KB-1, five distinct Dehalococcoides RDases and one Geobacter RDase were expressed under the conditions tested. Three of the five RDases included orthologs to the previously identified chlorinated ethene-dechlorinating enzymes VcrA, BvcA, and TceA. This study revealed substrate promiscuity for these three enzymes and provides a path forward to further explore the largely unknown RDase protein family. PMID:23204411

Tang, Shuiquan; Chan, Winnie W. M.; Fletcher, Kelly E.; Seifert, Jana; Liang, Xiaoming; Löffler, Frank E.; Adrian, Lorenz

2013-01-01

2

Surfactant Templated Polyacrylamide Gels  

NASA Astrophysics Data System (ADS)

The controlled modification of gel structure by using surfactant self-assemblies as templates provides new opportunities in the development of novel materials. Polyacrylamide gels were synthesized in the presence of tetradecyltrimethylammonium bromide (TTAB) surfactant. Small-angle X-ray scattering (SAXS) results indicate that acrylamide monomer does not prevent the self-assembly of TTAB surfactants. Dynamic rheology measurements indicated a transition from an isotropic micellar phase to a hexagonal columnar phase occurred about 10% higher TTAB concentration in the presence of acrylamide (the transition occurs at 35% (by weight) for TTAB in buffer solution). The presence of surfactant during the gelation profoundly affected the final gel structure. Real time rheology measurements showed evidence of a demixing of the polymer and the surfactant phase in gels formed in the presence of high TTAB concentration (> 30% by weight) leading to the formation of highly macroporous gels. Bulk structure characterization using SAXS showed that TTAB micelles were separated by about 10 nm in gels synthesized in the presence of low and moderate TTAB concentration (< 30%). Protein separation on gels templated by TTAB surfactants showed significant improvements over conventional gels.

Chakrapani, Mukundan; van Winkle, D. H.; Rill, R. L.

2003-03-01

3

Separation of Native Allophycocyanin and R-Phycocyanin from Marine Red Macroalga Polysiphonia urceolata by the Polyacrylamide Gel Electrophoresis Performed in Novel Buffer Systems  

PubMed Central

Three buffer systems of Imidazole?Acetic acid, HEPES?Imidazole/Bis-tris and Bis-tris?HEPES?MES were designed based on the principle of discontinuous polyacrylamide gel electrophoresis (PAGE) for the native PAGE which could be performed in pH 7.0 and 6.5 in order to analyze and prepare the minor components of allophycocyanin (AP) and R-phycocyanin (R-PC) from marine red macroalga Polysiphonia urceolata. These AP and R-PC phycobiliproteins are easily denatured in alkaline environments. The obtained results demonstrated that the PAGE modes performed in the buffer systems of HEPES?Imidazole/Bis-tris and Bis-tris?HEPES?MES gave the satisfactory resolution and separation of AP and R-PC proteins. The absorption and fluorescence spectra of the AP and R-PC proteins which were prepared by the established PAGE modes proved that they maintained natural spectroscopic characteristics. The established PAGE modes may also provide useful references and selections for some other proteins that are sensitive to alkaline environments or are not effectively separated by the classical PAGE modes performed normally in alkaline buffer systems. PMID:25166028

Wang, Yu; Gong, Xueqin; Wang, Shumei; Chen, Lixue; Sun, Li

2014-01-01

4

RNA purification by preparative polyacrylamide gel electrophoresis.  

PubMed

Preparative polyacrylamide gel electrophoresis (PAGE) is a powerful tool for purifying RNA samples. Denaturing PAGE allows separation of nucleic acids that differ by a single nucleotide in length. It is commonly used to separate and purify RNA species after in vitro transcription, to purify naturally occurring RNA variants such as tRNAs, to remove degradation products, and to purify labeled RNA species. To preserve RNA integrity following purification, RNA is usually visualized by UV shadowing or stained with ethidium bromide or SYBR green dyes. PMID:24034329

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

2013-01-01

5

The development of simple and sensitive small-molecule fluorescent probes for the detection of serum proteins after native polyacrylamide gel electrophoresis.  

PubMed

In this paper, a simple and sensitive small-molecule fluorescent probe, 2,5-dihydroxy-4'-dimethylaminochalcone (DHDMAC), was designed and synthesized for the detection of human serum proteins via hydrophobic interactions after polyacrylamide gel electrophoresis (PAGE). This probe produced lower fluorescence emission in the absence of proteins, and the emission intensity was significantly increased after the interaction with serum proteins. To demonstrate the imaging performance of this probe as a fluorescent dye, a series of experiments was conducted that included sensitivity comparison and 2D-PAGE. The results indicated that the sensitivity of DHDMAC staining is comparable to that of the most widely used fluorescent dye, SYPRO Ruby, and more protein spots (including thyroxine-binding globulin, angiotensinogen, afamin, zinc-?-2-glycoprotein and ?-1-antichymotrypsin) were detected after 2D-PAGE. Therefore, DHDMAC is a good protein reporter due to its fast staining procedure, low detection limits and high resolution. PMID:22475746

Wang, Fangfang; Huang, Lingyun; Na, Na; He, Dacheng; Sun, Dezhi; Ouyang, Jin

2012-05-21

6

Micro-size polyacrylamide gel electrophoresis system  

NASA Astrophysics Data System (ADS)

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

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

1987-09-01

7

Dynamics of sodium dodecyl sulfate micelles in polyacrylamide gels  

NASA Astrophysics Data System (ADS)

Hydrophilic polyacrylamide gels exhibit interesting elastic properties which can be probed by dynamic light scattering. The dynamic structure factors of such gels and of gels which were polymerized in the presence of high concentrations of sodium dodecyl sulfate (SDS) micelles were measured. It was found that the gels containing SDS decay initially according to a stretched exponential, followed by a long time simple exponential decay, whereas the pure gel decay is single exponential at all times. Furthermore, the initial decays of all SDS/gel systems are nearly identical, while the long-time decays are clearly a function of SDS concentration. We interpret the initial decay as associated with local polyacrylamide elasticity unaffected by the presence of the micelles and the long time decays as characteristic of gel modes slowed by the various densities of SDS micelles.

Reyna, A.; Liu, Yingjie; van Winkle, David H.

1998-03-01

8

Polyacrylamide gel miniaturization improves protein visualization and autoradiographic detection  

SciTech Connect

Polyacrylamide gels shrink to one-quarter of their original area when soaked in a 50% (w/v) solution of polyethylene glycol. Gel miniaturization improves the contrast of protein bands, with four valuable consequences. (i) A 5- to 10-fold increase in sensitivity for Coomassie blue is observed. (ii) Gels are more durable; i.e., they resist tearing when wet and they do not crack during drying under vacuum. (iii) Shrunken gels give sharper photographic images and provide better interlane protein band comparisons. (iv) Condensed protein bands lead to an increased sensitivity for detecting low-abundance, radioactively-labeled proteins by fluorography.

Mohamed, M.A.; Lerro, K.A.; Prestwich, G.D.

1989-03-01

9

Renaturation of enzymes after polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate  

SciTech Connect

A number of enzymes, including amylases, dehydrogenases, and proteases, were shown to be renaturable after polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Enzyme activity was detected in situ by action on substrates introduced into the gel and subsequent staining of either the product or unreacted substrate. Enzymes appeared to recover activity as soon as the detergent diffused out of the gel. Renatured enzymes were retained in gels after electrophoresis longer than native enzymes which had been subjected to electrophoresis in the absence of detergent. Re-electrophoresis of the renatured enzymes showed that part of the retained activity was physically anchored to the gel, possibly by the folding of polypeptides around the gel matrix as the enzymes were renatured.

Lacks, S.A.; Springhorn, S.S.

1980-08-10

10

Jet injection into polyacrylamide gels: investigation of jet injection mechanics.  

PubMed

Jet injectors employ high-velocity liquid jets that penetrate into human skin and deposit drugs in the dermal or subdermal region. Although jet injectors have been marketed for a number of years, relatively little is known about the interactions of high-speed jets with soft materials such as skin. Using polyacrylamide gels as a model system, the mechanics of jet penetration, including the dependence of jet penetration on mechanical properties, was studied. Jets employed in a typical commercial injector, (orifice diameter: 152 microm, velocity: 170-180 m/s) were used to inject fluid into polyacrylamide gels possessing Young's moduli in the range of 0.06-0.77 MPa and hardness values in the range of 4-70 H(OO). Motion analysis of jet entry into polyacrylamide gels revealed that jet penetration can be divided into three distinct events: erosion, stagnation, and dispersion. During the erosion phase, the jet removed the gel at the impact site and led to the formation of a distinct cylindrical hole. Cessation of erosion induced a period of jet stagnation ( approximately 600 micros) characterized by constant penetration depth. This stage was followed by dispersion of the liquid into the gel. The dispersion took place by crack propagation and was nearly symmetrical with the exception of injections into 10% acrylamide (Young's modulus of 0.06 MPa). The penetration depth of the jets as well as the rate of erosion decreased with increasing Young's modulus. The mechanics of jet penetration into polyacrylamide gels provides an important tool for understanding jet injection into skin. PMID:15212923

Schramm-Baxter, Joy; Katrencik, Jeffrey; Mitragotri, Samir

2004-08-01

11

The electrophoresis of transferrins in urea/polyacrylamide gels.  

PubMed Central

The denaturation of transferrin by urea has been studied by (a) electrophoresis in polyacrylamide gels incorporating a urea gradient, (b) measurements of the loss of iron-binding capacity and (c) u.v. difference spectrometry. In human serum transferrin and hen ovotransferrin the N-terminal and C-terminal domains of the iron-free protein were found to denature at different urea concentrations. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 7. PMID:7213345

Evans, R W; Williams, J

1980-01-01

12

Preparative electrophoresis on linear polyacrylamide-agarose composite gels.  

PubMed

A preparative method for isolating centigram quantities of high molecular weight polypeptide chains with high resolution and recovery uses linear polyacrylamide/agarose composite (LPAC) gels as electrophoretic media from which the polypeptides can be easily extracted. The composites are prepared in a manner yielding linear copolymers of acrylamide and 1-allyloxy-2,3-propanediol within 2% agarose gels. After electrophoresis in sodium dodecyl sulfate (SDS), protein bands were rapidly visualized for excision by briefly immersing the gel in cold 0.1 M KCl which precipitates the protein-associated SDS. The gel slices are then freeze-thawed to disrupt the agarose matrix and promote syneresis of fluid upon centrifugation. The polypeptides are then separated from the polyacrylamide in the supernatant solution by precipitating with either acidic isopropanol, trichloroacetic acid, ammonium sulfate or other general protein precipitants. As determined with polypeptide chains of fibrinogen and its cross-linked derivatives, recoveries were virtually complete (95.4% +/- 2.2%), and were independent of molecular weights over the range tested (10(4) --10(6)). PMID:8907537

Shainoff, J R; Smejkal, G B; Mitkevich, O; DiBello, P M

1996-01-01

13

Denaturing Urea PAGE -Small Gel 1. Prepare denaturing polyacrylamide gel solution. Use Gibco/BRL apparatus.  

E-print Network

31 Denaturing Urea PAGE - Small Gel 1. Prepare denaturing polyacrylamide gel solution. Use Gibco denatures nucleic acids. 4. Denature samples. To RNA, add an equal volume of sample buffer (100 µl formamide water in bath). Chill on ice. Spin briefly. Thaw frozen RNA samples just before denaturation and loading

Aris, John P.

14

Analysis of RNA by analytical polyacrylamide gel electrophoresis.  

PubMed

Polyacrylamide gel electrophoresis (PAGE) is a powerful tool for analyzing RNA samples. Denaturing PAGE provides information on the sample composition and structural integrity of the individual RNA species. Nondenaturing gel electrophoresis allows separation of the conformers and alternatively folded RNA species. It also can be used to resolve RNA protein complexes and to detect RNA complex formation by analyzing changes in the electrophoretic mobility of the RNA. RNA can be visualized within gels by different methods depending on the nature of the detection reagent. RNA molecules can be stained with various dyes, including toluidine blue, SYBR green, and ethidium bromide. Radioactively labeled RNA molecules are visualized by autoradiography, and fluorescently labeled RNA molecules can be observed with a fluorescence scanner. Generally, gels between 0.4 and 1.5mm thick are used for analytical PAGE. Gels thinner than 1mm are fragile and thus usually are not stained but rather are used for radiolabeled RNA. The gels are dried and the radiolabeled RNA is visualized by autoradiography. PMID:24034328

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

2013-01-01

15

Preliminary study of a normoxic polyacrylamide gel doped with iodine  

NASA Astrophysics Data System (ADS)

At the medical beamline of the European Synchrotron Radiation Facility (ESRF), a new radiotherapy technique called synchrotron stereotactic radiotherapy (SSR) is under development. During an SSR treatment, it has been demonstrated that iodine should perfuse the tumour for achieving acceptable dose distributions within a human head (Boudou C, Balosso J, Estève F and Elleaume H 2005 Phys. Med. Biol. 50 4841-4851). The aim of this study was to experimentally assess the dose enhancement due to iodine. We compared the results obtained using a standard polyacrylamide gel in the presence or absence of an iodinated contrast agent.

Boudou, Caroline; Troprès, Irène; Estève, François; Elleaume, Hélène

2006-12-01

16

Aggregative properties of Rhodamine dyes in polyacrylamide hydrophilic gel media  

NASA Astrophysics Data System (ADS)

The visible absorption spectra of two Rhodamine dyes (R6G and RB) in aqueous solutions, and in the polyacrylamide hydrogel matrix with different composition were studied at room temperature. The spectral properties of the dye-loaded hydrogel were also investigated. The transport and the solute-solute interactions of the ionic dyes in aqueous solutions across the hydrophilic gels were calculated. The monomer-dimer equilibrium of these ionic dyes in water and in different composition of hydrogel environment with different soaking time has been investigated by means of UV-Vis spectroscopy. The natures of the interacting pairs in these dyes were discussed using the Kasha exciton theory.

Zakerhamidi, M. S.; Moghadam, M.; Karimi, A.

2013-02-01

17

Polyacrylamide gels synthesized in the presence of surfactants  

NASA Astrophysics Data System (ADS)

The polymerization of acrylamide monomers in the presence of surfactant self-assemblies produces gels with variable pore architecture. Polyacrylamide gels were formed by polymerizing acrylamide plus a cross-linker in the presence of surfactants, which were then removed by soaking in distilled water. Gels formed in the presence of over 28% surfactant (by weight) formed clear, but became opaque upon removal of the surfactants. Other gels formed and remained clear. Several analytical techniques such as X-ray Scattering, Dynamic Rheology measurements, Optical Polarized Microscopy, and Atomic Force Microscopy (AFM) have been used to characterize the formation and the resulting gel structure. The surface morphology as imaged by AFM was studied by numerical scaling analysis. The surface morphology of the gels was studied by several one- and two-dimensional numerical scaling methods. The structure of the final gels were highly dependent on the amount of surfactant present during the formation of gels. At low surfactant concentrations (<25% by weight), the surfactant micelles are randomly distributed throughout the gel matrix. The average spacing between individual micelles is about 10 nm as indicated by X-ray scattering experiments. When the TTAB concentration is increased to moderate levels (25--28%), though the surfactant micelles are randomly distributed, a few surfactant-rich regions may form in the gel matrix. At high TTAB concentrations, phase separation of TTAB from the polymer leads to the formation of many surfactant-rich domains. A model for the gel structure based on symmetry and packing considerations for lattices of spheres of different concentrations was developed. This model was successfully used to interpret the physical observations, the experimental results, and the results from the scaling analysis. Highly porous gel networks with a high degree of mechanical strength have thus been synthesized. The controlled modification of gel structure provides new opportunities in the development of novel materials. A few areas of application include enzyme fixation for building biosensors, controlled release systems for drug delivery, support matrices for bio-molecule separation. The process of gel formation in the presence of unreactive surfactants can also be extended to alter the structure of other polymer materials.

Chakrapani, Mukundan

18

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

19

Silver stain for proteins in polyacrylamide gels: A modified procedure with enhanced uniform sensitivity  

Microsoft Academic Search

The rapid, ultrasensitive silver stains that have been developed recently for detecting proteins in polyacrylamide gels show variation in staining from gel to gel and do not stain certain proteins at all. It was found that treatment of gels with dithiothreitol prior to impregnation with silver nitrate results in more reproducible staining patterns that are also qualitatively similar to those

JAMES H. MORRISSEY

1981-01-01

20

Simple, Sensitive Zymogram Technique for Detection of Xylanase Activity in Polyacrylamide Gels  

PubMed Central

A method capable of detecting as little as 0.11 U of xylanase activity in polyacrylamide gels was developed. The method entails incubation of protein gels in contact with substrate gels containing unmodified xylan, followed by immersion of substrate gels in 95% ethanol. Resulting zymograms contain transparent bands corresponding to enzymatic activity against an opaque background. Images PMID:16348200

Royer, John C.; Nakas, J. P.

1990-01-01

21

Electrophoretic Transfer of Proteins from Polyacrylamide Gels to Nitrocellulose Sheets: Procedure and Some Applications  

Microsoft Academic Search

A method has been devised for the electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets. The method results in quantitative transfer of ribosomal proteins from gels containing urea. For sodium dodecyl sulfate gels, the original band pattern was obtained with no loss of resolution, but the transfer was not quantitative. The method allows detection of proteins by autoradiography

Harry Towbin; Theophil Staehelin; Julian Gordon

1979-01-01

22

Polyacrylamide gel method: synthesis and property of BeO nanopowders  

Microsoft Academic Search

Effects of monomer (AM) concentration, monomer\\/crosslinker (AM\\/MBAM) ratio and salt concentration on the thermal behavior\\u000a of precursor gel and the properties of BeO nanopowder synthesized by polyacrylamide gel method were investigated. The decomposition\\u000a process of precursor gel was also studied. The decomposition process of precursor gel is that, first, the extraction of free\\u000a and crystallized water, and then the thermal

Xiaofeng Wang; Richu Wang; Chaoqun Peng; Tingting Li; Bing Liu

2011-01-01

23

Biochemical Identification of the Two Races of Radopholus similis by Polyacrylamide Gel Electrophoresis.  

PubMed

Analysis of proteins of the banana and citrus race of Radopholus similis was carried out by several different types of polyacrylamide gel electrophoresis. These included standard slab gel, SDS slab gel, gradient slab gel, and two-ditnensional slab gel electrophoresis. A major band difference was detected between the two races by slab gel electrophoresis. However, several other poorly resolved but consistent hands of high molecular weight proteins near the gel origin also were considered as diagnostic. Resolution of protein bands was greatly improved by SDS and gradient slab gel electrophoresis, but no differences could be detected among the proteins resolved between the two rares with these techniques. Two-dimensional gels revealed a large number of proteins, but background staining obscured them hindering interpretation. When nematode races were reared on three different host plants, no differences in protein patterns were detected between them, indicating host preferences does not play a role in determining the types proteins occurring in these nematodes. PMID:19295815

Huettel, R N; Dickson, D W; Kaplan, D T

1983-07-01

24

Dna electrophoresis in photopolymerized polyacrylamide gels on a microfluidic device  

E-print Network

DNA gel electrophoresis is a critical analytical step in a wide spectrum of genomic analysis assays. Great efforts have been directed to the development of miniaturized microfluidic systems (“lab-on-a-chip” systems) to perform low-cost, high...

Lo, Chih-Cheng

2009-05-15

25

Femtomole sequencing of proteins from polyacrylamide gels by nano-electrospray mass spectrometry  

Microsoft Academic Search

MOLECULAR analysis of complex biological structures and processes increasingly requires sensitive methods for protein sequencing. Electrospray mass spectrometry1 has been applied to the high-sensitivity sequencing of short peptides2, but technical difficulties have prevented similar success with gel-isolated proteins. Here we report a simple and robust technique for the sequencing of proteins isolated by polyacrylamide gel electro-phoresis, using nano-electrospray3,4 tandem mass

Matthias Wilm; Andrej Shevchenko; Tony Houthaeve; Stephen Breit; Lothar Schweigerer; Theodore Fotsis; Matthias Mann

1996-01-01

26

Fast isoelectric focusing of milk proteins on small ultrathin polyacrylamide gels containing urea.  

PubMed

The preparation of 0.45 mm thin polyacrylamide gels, containing urea, for horizontal micro isoelectric focusing of milk proteins with PhastSystem is described. Isoelectric focusing in the small gels, stained either with Coomassie Brilliant Blue R-250 or with the more sensitive silver stain, affords a fast and sensitive procedure for an analysis of milk and cheese proteins. The procedure can be effectively exploited in detecting adulteration in ovine cheese with bovine milk. PMID:2776737

Moio, L; Di Luccia, A; Addeo, F

1989-07-01

27

Ultrasonic Investigation of the Gelation Process of Poly(Acrylamide) Gels  

E-print Network

Ultrasonic Investigation of the Gelation Process of Poly(Acrylamide) Gels Tomohisa Norisuye,*1 examined in order to investigate the gelation process accompanied by phase separation. Keywords: acrylamide, PAAms are synthesized with acrylamide (AAm) and bisacrylamide (BIS) as starting compounds, so that PAAms

Page, John

28

Silver staining of proteins in polyacrylamide gels Mireille Chevallet, Sylvie Luche and Thierry Rabilloud*  

E-print Network

Silver staining of proteins in polyacrylamide gels Mireille Chevallet, Sylvie Luche and Thierry author email: thierry.rabilloud@cea.fr Phone +33 438 783 212, Fax : +33 438 789 803 Abstract Silver. The sequential phases of silver staining are protein fixation, then sensitization, then silver impregnation

Paris-Sud XI, Université de

29

Imaging findings of breast augmentation with injected hydrophilic polyacrylamide gel: Patient reports and literature review  

Microsoft Academic Search

Hydrophilic polyacrylamide gel (PAAG) is a nonresorbable soft tissue filler that has been used as implant material for breast augmentation in some countries, particularly from the Asian continent. Many complications associated with hydrogel use have been reported in the clinical literature including inflammation, persistent mastodynia, formation of multiple lumps, poor cosmetic results, glandular atrophy, and significant spread of hydrogel into

Najoua Ben Khedher; Julie David; Isabelle Trop; Suzanne Drouin; Laurence Peloquin; Lucie Lalonde

2011-01-01

30

Microfluidic 2-D PAGE using multifunctional in situ polyacrylamide gels and discontinuous buffers.  

PubMed

A two-dimensional microfluidic system is presented for intact protein separations combining isoelectric focusing (IEF) and sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) employing in situ photopolymerized polyacrylamide (PAAm) gels. The PAAm gels are used for multiple functions. In addition to serving as a highly-resolving separation medium for gel electrophoresis, discrete polyacrylamide gel plugs are used to enable the efficient isolation of different on-chip media including anolyte, catholyte, and sample/ampholyte solutions for IEF. The gel plugs are demonstrated as on-chip reagent containers, holding defined quantities of SDS for on-chip SDS-protein complexation, and enabling the use of a discontinuous buffer system for sample band sharpening during SDS-PAGE. The 2-D chip also employs several unique design features including an angled isoelectric focusing channel to minimize sample tailing, and backbiasing channels designed to achieve uniform interdimensional sample transfer. Separation results using E. coli cell lysate are presented using a 10-channel chip with and without the discontinuous buffer system, with resolving power more than doubled in the former case. Further improvements in separation resolution are demonstrated using a 20-channel chip design. PMID:19190795

Yang, Shuang; Liu, Jikun; Lee, Cheng S; Devoe, Don L

2009-02-21

31

Immobilization of microbial cells using polyvinyl alcohol (PVA) — polyacrylamide gels  

Microsoft Academic Search

A novel cell immobilization technique is developed in which polyvinyl alcohol is crosslinked with boric acid with addition of an acrylamide as a polymerizing agent. The presence of the polymerizing agent overcomes the problem of swelling of PVA gels in aqueous solution. The new immobilization method was used to entrap a phenol-degrading microorganism, a species of Pseudomonas. Phenol was successfully

Wang Jianlong; Hou Wenhua; Qian Yicr

1995-01-01

32

Identification of frankia strains by two-dimensional polyacrylamide gel electrophoresis.  

PubMed

Fifteen Frankia strains from five different plant species were analyzed by two-dimensional polyacryl-amide gel electrophoresis to determine their relatedness by comparing the polypeptide patterns obtained. Three major subgroups (A, C, and D) were found in the Alnus-Comptonia-Myrica cross-inoculation group. An isolate from Purshia tridentata had a unique protein pattern and represents a distinct group of frankiae. Members of group A were isolated from root nodules of Alnus incana subsp. rugosa and Alnus viridis subsp. crispa. Group C organisms were from A. incana subsp. rugosa and Comptonia peregrina nodules, and group D organisms were from A. incana subsp. rugosa, A. viridis subsp. cripsa, and Myrica pensylvanica root nodules. Isolates from each gel group were obtained at several widely separated geographical locations. The results indicate that two-dimensional polyacrylamide gel electrophoresis is useful for identifying Frankia isolates. PMID:16346488

Benson, D R; Buchholz, S E; Hanna, D G

1984-03-01

33

Identification of Frankia Strains by Two-Dimensional Polyacrylamide Gel Electrophoresis  

PubMed Central

Fifteen Frankia strains from five different plant species were analyzed by two-dimensional polyacryl-amide gel electrophoresis to determine their relatedness by comparing the polypeptide patterns obtained. Three major subgroups (A, C, and D) were found in the Alnus-Comptonia-Myrica cross-inoculation group. An isolate from Purshia tridentata had a unique protein pattern and represents a distinct group of frankiae. Members of group A were isolated from root nodules of Alnus incana subsp. rugosa and Alnus viridis subsp. crispa. Group C organisms were from A. incana subsp. rugosa and Comptonia peregrina nodules, and group D organisms were from A. incana subsp. rugosa, A. viridis subsp. cripsa, and Myrica pensylvanica root nodules. Isolates from each gel group were obtained at several widely separated geographical locations. The results indicate that two-dimensional polyacrylamide gel electrophoresis is useful for identifying Frankia isolates. Images PMID:16346488

Benson, David R.; Buchholz, S. E.; Hanna, D. G.

1984-01-01

34

Specific staining of sialic acid components on sodium dodecyl sulfate polyacrylamide gel.  

PubMed

Specific staining of sialic acid components after sodium dodecyl sulfate polyacrylamide gel electrophoresis can be carried out as follows: 1) extract glycoprotein of erythrocyte membranes or serum by the phenol-saline method, 2) electrophorese the extract on 5% polyacrylamide gel containing 0.1% sodium dodecyl sulfate at constant current, 3) treat the gel with chilled 0.04 M HIO4 for 45 minutes, 4) replace the periodic acid solution with one containing resorcinol 0.6 g, conc. HCl 50 ml, 0.1 M CuSO4 0.5 ml and H2O 50 ml, 5) warm the container in boiling water until blue violet sialic acid bands become clear, 6) replace the staining solution with a mixture of equal parts water and concentrated HCl and observe at once. PMID:6166103

Umezu, C; Yoshioka, N; Takahashi, K

1981-03-01

35

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

SciTech Connect

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 NaBH/sub 4/-reduced cellulo-oligosaccharides, 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.

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

1984-01-01

36

Polyacrylamide gel electrophoretic methods in the separation of structural muscle proteins.  

SciTech Connect

Polyacrylamide gel electrophoresis plays a major role in analyzing the function of muscle structural proteins. This review describes one- and two-dimensional gel electrophoretic methods for qualitative and quantitative investigation of the muscle proteins, with special emphasis on determination of protein phosphorylation. The electrophoretic studies established the subunit structures of the muscle proteins, characterized their multiple forms, revealed changes in subunit composition or shifts in isoform distribution of specific proteins during development, upon stimulation or denervation of the muscle. Protein phosphorylation during muscle contraction is preferentially studied by two-dimensional gel electrophoresis. The same method demonstrated protein alterations in human neuromuscular diseases.

Barany, K.; Barany, M.; Giometti, C. S.; Center for Mechanistic Biology and Biotechnology; Univ. of Illinois at Chicago

1995-04-28

37

Pressure-induced volume phase transition of polyacrylamide gels in acetone-water mixtures  

NASA Astrophysics Data System (ADS)

Equilibrium swelling curves of ionized polyacrylamide gels immersed in acetone-water mixtures were measured as a function of pressure up to pressures of 300 MPa. The gels, which shrank at atmospheric pressure, underwent an abrupt volume change (pressure-induced volume phase transition) from a shrunken state to a swollen state at the transition pressure. The transition pressure increased with an increase of acetone concentration. The pressure-induced volume phase transition can be interpreted by taking account of the free-energy change ?V?P between swollen (hydrated) and shrunken (dehydrated) states. The ?V represents the difference between the molar volume of water structured around hydrophilic groups of polyacrylamide chains and that of free water in the bulk mixtures. The estimated value of ?V is -3.3 mL/mol, which qualitatively agrees with that obtained from the experiments of denaturation of proteins. The pressure-induced volume phase transition is generally expected in many hydrogels.

Kato, Eiji

2000-07-01

38

Detection of single sequence repeat polymorphisms in denaturing polyacrylamide sequencing gels by silver staining  

Microsoft Academic Search

Large-scale use of molecular markers in plant breeding is limited by the throughput capacity for genotyping. DNA polymorphisms\\u000a can be detected in denaturing polyacrylamide gels indirectly by nucleotide labeling or directly by staining. Fluorescent-labeling\\u000a or radiolabeling requires sophisticated infrastructure not always available in developing countries. We present an improved\\u000a low-cost method for silver staining and compare it to 2 other

S. Creste; A. Tulmann Neto; A. Figueira

2001-01-01

39

Increased 131I accumulation in the polyacrylamide hydrophilic gel used for breast augmentation.  

PubMed

A 37-year-old woman with papillary thyroid cancer received repeat 131I therapy. The first posttherapy scan revealed only activity in the neck. However, both the second and third posttherapy scans showed intense activity in the anterior lower chest bilaterally, suggestive of breast uptake. However, the SPECT/CT images demonstrated that the iodine activity was not located in the breast tissue. Instead, the activity was inside the polyacrylamide hydrophilic gels she received 10 years ago for breast augmentation. PMID:24566417

Lv, Jing; Qu, Yumin; Zhang, Min; Pan, Yu; Zhang, Yifan

2014-04-01

40

A paper-based electroelution system for protein recovery from stained sodium dodecyl sulfate-polyacrylamide gels.  

PubMed

Electroelution is a widely used methodology for protein purification. In this study, a practical and low-cost system for protein electroelution from stained polyacrylamide gels was developed. For this, a horizontal protein electroelution cuve was constructed with glass plates, 1.5-ml capacity microcentrifuge tubes, and dialysis membrane. Analyses of the system efficiency showed high protein recovery from nonfixed and fixed sodium dodecyl sulfate (SDS)-polyacrylamide gels. PMID:18396142

Branco, Alan T; Ferreira, Beatriz dos S; de Souza Filho, Gonçalo A

2008-10-15

41

Application of optical methods for dose evaluation in normoxic polyacrylamide gels irradiated at two different geometries  

NASA Astrophysics Data System (ADS)

Normoxic gels are frequently used in clinical praxis for dose assessment or 3-D dose imaging in radiotherapy due to their relative simple manufacturing process under normal atmospheric conditions, spatial stability and well expressed modification feature of physical properties which is related to radiation induced polymerization of gels. In this work we have investigated radiation induced modification of the optical properties of home prepared normoxic polyacrylamide gels (nPAG) in relation to polymerization processes that occur in irradiated gels. Two irradiation geometries were used for irradiation of gel samples: broad beam irradiation geometry of teletherapy unit ROKUS-M with a 60Co source and point source irradiation geometry using 192Ir source of high dose rate afterloading brachytherapy unit MicroSelectron v2 which was inserted into gel via 6 Fr (2 mm thick) catheter. Verification of optical methods: UV-VIS spectrometry, spectrophotometry, Raman spectroscopy for dose assessment in irradiated gels has been performed. Aspects of their application for dose evaluation in gels irradiated using different geometries are discussed. Simple pixel-dose based photometry method also has been proposed and evaluated as a potential method for dose evaluation in catheter based interstitial high dose rate brachytherapy.

Adliene, D.; Jakstas, K.; Vaiciunaite, N.

2014-03-01

42

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

43

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

44

The defect of Mk erythrocytes as revealed by sodium dodecylsulphate--polyacrylamide gel electrophoresis.  

PubMed

The membrane glycoprotein defect of Mk red cells was studied using discontinuous sodium dodecylsulphate--polyacrylamide gel electrophoresis, carbohydrate analytical procedures and lectins. The results suggest that Mk erythrocyte membranes contain only about half of the normal amount of the MN and Ss sialoglycoproteins, both molecules being not qualitatively different from normal. The major membrane protein exhibits an increased molecular weight in the above red cells. Some data on Mg and Miltenberger class five cells are presented for comparison. The results on Mk erythrocytes support the operon concept of the MNSs blood group system proposed previously. PMID:894053

Dahr, W; Uhlenbruck, G; Knott, H

1977-06-01

45

Effect of polyacrylamide hydrophilic gel composition on photo-physical behavior of Oxazine 750  

NASA Astrophysics Data System (ADS)

Electronic absorption spectra of Oxazine 750 dye in aqueous solutions and in polyacrylamide hydrogel matrix with different structural composition were studied at room temperature. The transport and the solute-solute interactions of the ionic dye in aqueous solutions across the hydrophilic gels were investigated via exploring spectral properties of the dye-loaded hydrogel. The nature of the dye pair interactions in these media was discussed using the Kasha exciton theory. In addition, the monomer-dimer equilibrium of Oxazine 750 in hydrogels with different compositional percentage has been determined by means of UV-vis spectroscopy and least square fitting methods.

Zakerhamidi, M. S.; Tajalli, H.; Ghanadzadeh, A.; Milanchian, K.; Hosseini Nasab, N.; Moghadam, M.

2010-09-01

46

Temperature dependence of free volume of polyacrylamide gels studied by positron lifetime measurements  

NASA Astrophysics Data System (ADS)

Changes of positronium (Ps) cavity radii in polyacrylamide and poly( N-isopropylacrylamide) gels were studied from 120 to 300 K by positron lifetime technique and it has been shown that the Ps cavity radius in the hydrogels changes by three or four stages. Temperature dependence of the Ps cavity radius exhibits variations similar to common polymers around the glass transition temperature. Hydrophilicity of the polymer chains significantly affects the Ps cavity radius just below 273 K. These results suggest an important role of free volume on the state of water in hydrogels.

Ito, Kenji; Ujihira, Yusuke; Yamashita, Takashi; Horie, Kazuyuki

2000-06-01

47

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. PMID:23002394

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

2012-01-01

48

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

PubMed

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. PMID:23002394

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

2012-07-21

49

Comparative biotolerance of polyacrylamide-agarose gel, silicone rubber and microporous PTFE as soft tissue implants.  

PubMed

A comparative study has been carried out on the biotolerance to subcutaneous, intramuscular and intraperitoneal implants of silicone rubber, microporous PTFE and polyacrylamide-agarose gel for 6 wk in the rat. Assessment was quantitative histology for capsule thickness, fibroblast density, mononuclear cell density, multinucleated giant cell density and also collagen packing density. The trial polymers were compared to historical data on healing in dummy procedures and on two hydrophilic graft copolymers of high biotolerance namely polyethylene-acrylic acid and microporous polypropylene-acrylic acid. The rank ordering of the trial polymers for all criteria except collagen packing, was for the least response to be to polyacrylamide-agarose and the most to silicone rubber, with the differences being significant (p less than 0.05) for capsule thickness and mononuclear cell density. Polyacrylamide-agarose was similar in response to the two hydrophilic copolymers; microporous PTFE was slightly more reactive and silicone rubber was significantly more reactive (p less than 0.05). PMID:3741964

Taylor, D E; Penhallow, J E

1986-07-01

50

Examination of the Protein Composition of the Cell Envelope of Escherichia coli by Polyacrylamide Gel Electrophoresis  

PubMed Central

An envelope preparation containing the cell wall and cytoplasmic membrane of Escherichia coli was obtained by breaking the cells with a French pressure cell and sedimentating the envelope fraction by ultracentrifugation. This fraction was prepared for polyacrylamide gel electrophoresis by dissolving the protein in an acidified N,N?-dimethylformamide, removing lipids by gel filtration in the same organic solvent and removing the solvent by dialysis against aqueous urea solutions. More than 80% of the total protein of the envelope fraction was recovered in soluble form. Electrophoresis on sodium dodecyl sulfate-containing gels yielded from 20 to 30 well-resolved bands of protein. One major protein band was observed on the gels. This protein had a molecular weight of 44,000 and accounted for as much as 40% of the total protein of the envelope fraction. A double-labeling technique was used to examine the protein composition of the envelope fraction from cells grown under different sets of conditions which result in large changes in the levels of membrane-bound oxidative enzymes. These changes in growth conditions resulted in only minor alterations in the protein profiles observed on the gels, suggesting that this organism is able to adapt to changes in growth environment with only minor modifications of the major proteins of the cell envelope. PMID:4923077

Schnaitman, Carl A.

1970-01-01

51

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

52

Separation performance of single-stranded DNA electrophoresis in photopolymerized cross-linked polyacrylamide gels.  

PubMed

Considerable effort has been directed toward optimizing performance and maximizing throughput in ssDNA electrophoresis because it is a critical analytical step in a variety of genomic assays. Ultimately, it would be desirable to quantitatively determine the achievable level of separation resolution directly from measurements of fundamental physical properties associated with the gel matrix rather than by the trial and error process often employed. Unfortunately, this predictive capability is currently lacking, due in large part to the need for a more detailed understanding of the fundamental parameters governing separation performance (mobility, diffusion, and dispersion). We seek to address this issue by systematically characterizing electrophoretic mobility, diffusion, and dispersion behavior of ssDNA fragments in the 70-1,000 base range in a photopolymerized cross-linked polyacrylamide matrix using a slab gel DNA sequencer. Data are collected for gel concentrations of 6, 9, and 12%T at electric fields ranging from 15 to 40 V/cm, and resolution predictions are compared with corresponding experimentally measured values. The data exhibit a transition from behavior consistent with the Ogston model for small fragments to behavior in agreement with the biased reptation model at larger fragment sizes. Mobility data are also used to estimate the mean gel pore size and compare the predictions of several models. PMID:16331587

Lo, Roger C; Ugaz, Victor M

2006-02-01

53

Optimising the extraction of allergens in Betula pollen as determined by isoelectric focusing in polyacrylamide gels.  

PubMed

Water soluble proteins extracted from birch pollen are responsible for most of the allergic symptoms in central and northern Europe as well as in parts of northern U.S.A. and Canada. Previous immunological studies of pollen allergens by isoelectric focusing (IEF) in polyacrylamide gels (PAGs) used a variety of extraction methods with little regard to standardisation or optimisation. In the present study a variety of buffers with various pH, charged buffering ions and ionic strengths were evaluated against different extraction times and temperatures in order to determine the optimum conditions for protein extraction. The largest number of proteins, determined by IEF, were found when extractions were performed at 10 degrees C and for 1 hour. Coomassie Blue and silver staining methods were compared. PMID:8489693

Hjelmroos, M; Egen, N; Schumacher, M

1993-04-01

54

The identification of rat intestinal membrane enzymes after electrophoresis on polyacrylamide gels containing sodium dodecyl sulphate.  

PubMed Central

Brush-border membranes were isolated from the rat small intestine and then treated with sodium dodecyl sulphate under non-reducing conditions at room temperature. Analysis of the solubilized components by polyacrylamide-gel electrophoresis identified three major glycoproteins that co-migrate with glucoamylase-maltase-sucrase, lactase and isomaltase-maltase-sucrase activities. High activities of alkaline phosphatase and trehalase were detectable, but they could not be attributed to distinct co-migrating protein bands. Analysis of mucosa from the distal small intestine by the same methods showed a pattern of bands different from that obtained with the proximal intestine, which appeared to correlate with the relative deficiency of some of the enzymes in the distal region. PMID:697763

Hauri, H P; Green, J R

1978-01-01

55

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. PMID:23819755

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

2013-01-01

56

Neutron-scattering probe of complexes of sodium dodecyl sulfate and serum albumin during polyacrylamide gel electrophoresis.  

PubMed

Small-angle neutron scattering (SANS) is used to probe the conformation of SDS-BSA protein surfactant complexes during electrophoresis in cross-linked polyacrylamide gels. Contrast variation permits independent probing of the structure of protein-surfactant complexes with negligible scattering contributions from the polyacrylamide matrix. The conformation of the protein complexes in the gel is found to be independent of the electric fields that are applied in this work (10 V/cm). Furthermore, there are no signs of large-scale macromolecular orientation (anisotropy) in the scattering patterns. However, the scattering shows that there are significant interparticle correlations between the protein-surfactant complexes that are electrophoretically inserted into the gel. These interactions develop when the total concentration of protein in the gels reaches values that are larger than approximately 1 mg/mL. The correlations are due to molecular crowding in the small fraction of pores that are available for protein migration. PMID:19125631

Pozzo, Danilo C

2009-02-01

57

Silver staining of proteins in polyacrylamide gels: a general overview Thierry Rabilloud*, Laurent Vuillard+ , Claudine Gilly and Jean Jacques Lawrence  

E-print Network

1 Silver staining of proteins in polyacrylamide gels: a general overview Thierry Rabilloud (Running title): overview of silver staining methods for proteins +: Institut Laue-Langevin , BP156, 38042 silver staining of proteins, which are recalled in this paper, several methods of silver staining

Boyer, Edmond

58

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

59

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

60

Sodium dodecyl sulfate-polyacrylamide gel protein electrophoresis of freshwater photosynthetic sulfur bacteria.  

PubMed

Sodium dodecyl sulfate-polyacrylamide gel protein electrophoresis (SDS-PAGE) was carried out using different bacterial strains of the photosynthetic sulfur bacteria Chlorobium, Thiocapsa, Thiocystis, and Chromatium cultured in the laboratory, and the natural blooms in two karstic lakes (Lake Cisó and Lake Vilar, NE Spain) where planktonic photosynthetic bacteria (purple and green sulfur bacteria) massively developed accounting for most of the microbial biomass. Several extraction, solubilization, and electrophoresis methods were tested to develop an optimal protocol for the best resolution of the SDS-PAGE. Protein composition from different water depths and at different times of the year was visualized within a molecular mass range between 100 and 15 kDa yielding up to 20 different protein bands. Protein banding patterns were reproducible and changed in time and with depth in agreement with changes in photosynthetic bacteria composition. When a taxonomically stable community was followed in time, differences were observed in the intensity but not in the composition of the SDS-PAGE banding pattern. Three environmental variables directly related to the activity of sulfur bacteria (light, oxygen, and sulfide concentrations) had a significant effect on protein banding patterns and explained 33% of the variance. Changes in natural protein profiles of the bacterial blooms agreed with changes in species composition and in the in situ metabolic state of the populations. PMID:20524118

Osuna, M Begoña; Casamayor, Emilio O

2011-01-01

61

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

62

A method for detection of cellulases in polyacrylamide gels using 5-bromoindoxyl-beta-D-cellobioside: high sensitivity and resolution.  

PubMed

The assay of endo-1,4-beta-glucanases (cellulases) from Trichoderma reesei, T. longibrachiatum, and Sporotrichum pulverulentum by 5-bromoindoxyl-beta-D-cellobioside is described. The substrate is enzymatically cleaved to afford 5-bromoindoxyl and latter undergoes immediate azo coupling with Fast Red or oxidation by nitroblue monotetrazolium chloride, various forms of endoglucanases which can thus be assayed in polyacrylamide gel. PMID:2610340

Chernoglazov, V M; Ermolova, O V; Vozny, Y V; Klyosov, A A

1989-11-01

63

Electroblotting of multiple gels: a simple apparatus without buffer tank for rapid transfer of proteins from polyacrylamide to nitrocellulose.  

PubMed

A simple, horizontal device for rapid electrophoretic transfer of proteins from several polyacrylamide gels simultaneously is described. Up to six 'TRANS-UNITS' consisting of soaked filter paper on either side of polyacrylamide gel/nitrocellulose sheets that are separated by dialysis membranes are stacked between graphite plate electrodes. The only buffer reservoir in the apparatus is that in stacked, soaked filter paper. A special buffer system based on the isotachophoresis theory was developed for this purpose. The electrophoretic transfer was performed with equal efficiency in all TRANS-UNITS of the stack. Only traces of a few proteins remained in the polyacrylamide gel after transfer. With this apparatus, 50 protein bands from a human serum protein sample (diluted 1 : 100) were detected by immunoblotting with the retainment of the high resolution of the SDS-PAGE technique. The apparatus provided a constant current density of 0.8 mA/cm2 during the 1-h transfer time at 21 degrees C, irrespective of the number of TRANS-UNITS. The apparatus generated 1-5 W in joule heat, depending on the number of TRANS-UNITS in the stack. PMID:6530509

Kyhse-Andersen, J

1984-12-01

64

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 PMID:820647

Callahan, L T

1976-01-01

65

Detection of antimicrobial (poly)peptides with Acid urea polyacrylamide gel electrophoresis followed by Western immunoblot.  

PubMed

Antimicrobial (poly)peptides (AMPs) are ancient key effector molecules of innate host defense and have been identified in mammals, insects, plants, and even fungi (Nakatsuji and Gallo, J Invest Dermatol, 132: 887-895, 2012). They exhibit a cationic net charge at physiological pH and are rich in hydrophobic amino acids (Dufourc et al., Curr Protein Pept Sci, 13: 620-631, 2012). Their mode of action has been best investigated in bacteria. When assuming secondary structure the cationic and hydrophobic amino acids are sequestered creating a bipartitioned molecule in which the cationic amino acids mediate initial electrostatic interaction with the negatively charged bacterial surface and the hydrophobic amino acids mediate embedding into the bacterial membranes followed by a multitude of effects interfering with bacterial viability (Nicolas, FEBS J, 276: 6483-6496, 2009; Padovan et al., Curr Protein Pept Sci, 11: 210-219, 2010). However, immunomodulatory, antitumor, and other effects have been added to the ever increasing list of AMP functions (Pushpanathan et al., Int J Pept, 2013: 675391, 2013). Several classes of AMPs have been distinguished based on structure, namely anti-parallel beta-sheet, alpha-helical, circular, as well as disulfide bridge connectivity (Bond and Khalid, Protein Pept Lett, 17: 1313-1327, 2010). Many of the AMPs undergo posttranslational modification including further proteolysis. Biochemical analysis at the protein level is of great interest for a wide range of scientists and important when studying host-pathogen interaction, for example Salmonella invasion of the small intestine. Acid-urea polyacrylamide gel electrophoresis (AU-PAGE) followed by Western immunoblotting is an important tool for the identification and quantification of cationic AMPs. The protocol for these procedures outlined here describes, in detail, the necessary steps; including pouring the AU-gels, preparing the test samples, performing the electrophoretic separation and protein transfer to the membrane, and conducting the immunodetection using an alkaline phosphatase/NBT/BCIP system. A standard SDS-PAGE in comparison with AU-PAGE and the corresponding Western immunoblot are depicted in Fig. 1. PMID:25253251

Porter, Edith; Valore, Erika V; Anouseyan, Rabin; Salzman, Nita H

2015-01-01

66

Nongradient blue native gel analysis of serum proteins and in-gel detection of serum esterase activities.  

PubMed

The objective of the present study was to analyze serum protein complexes and detect serum esterase activities using nongradient blue native polyacrylamide gel electrophoresis (BN-PAGE). For analysis of potential protein complexes, serum from rat was used. Results demonstrate that a total of 8 gel bands could be clearly distinguished after Coomassie blue staining, and serum albumin could be isolated nearly as a pure protein. Moreover, proteins in these bands were identified by electrospray mass spectrometry and low-energy collision induced dissociation (CID)-MS/MS peptide sequencing and the existence of serum dihydrolipoamide dehydrogenase (DLDH) was confirmed. For studies of in-gel detection of esterase activities, serum from rat, mouse, and human was used. In-gel staining of esterase activity was achieved by the use of either ?-naphthylacetate or ?-naphthylacetate in the presence of Fast blue BB salt. There were three bands exhibiting esterase activities in the serum of both rat and mouse. In contrast, there was only one band showing esterase activity staining in the human serum. When serum samples were treated with varying concentrations of urea, esterase activity staining was abolished for all the bands except the one containing esterase 1 (Es1) protein that is known to be a single polypeptide enzyme, indicating that majority of these esterases were protein complexes or multimeric proteins. We also identified the human serum esterase as butyrylcholinesterase following isolation and partial purification using ammonium sulfate fractioning and ion exchange column chromatographies. Where applicable, demonstrations of the gel-based method for measuring serum esterase activities under physiological or pathophysiological conditions were illustrated. Results of the present study demonstrate that nongradient BN-PAGE can serve as a feasible analytical tool for proteomic and enzymatic analysis of serum proteins. PMID:21237726

Thangthaeng, Nopporn; Sumien, Nathalie; Forster, Michael J; Shah, Ruchir A; Yan, Liang-Jun

2011-02-15

67

Inducing pH responsiveness via ultralow thiol content in polyacrylamide (micro)gels with labile crosslinks.  

PubMed

Here we present the synthesis and characterization of pH responsive polyacrylamide microgels, synthesized via free radical polymerization of acrylamide and bis (acryloylcystamine) (BAC). The gels were made with ultralow amounts of thiol functional groups incorporated into the polymer. The resulting gel monoliths were mechanically chopped into microgel particles with size distributions ranging from 80 to 200 mum. The gels exhibit an interesting reversible pH-dependent rheological behavior which led to gelling of the colloidal suspension when the pH was increased, and a low-viscosity suspension was obtained when the pH was taken back to the original value. The viscosity of the colloidal system containing MBA crosslinked microgels remained insensitive to pH. This observation motivated further analysis; viscosity measurements of the highly viscous (gel-like) state of the BAC crosslinked microgel colloidal suspension were carried out to further understand the rheological behavior of the colloidal system. Electrophoretic mobility measurements as function of pH of the BAC and MBA crosslinked colloidal polyacrylamide microgel suspensions were performed. The swelling behavior of the microgels for both colloidal systems was also determined as function of pH using static light scattering. This swelling behavior was used to rationalize the observed rheological behavior. The work presented here demonstrates that free thiol groups present within a polymer gel matrix confer pH responsive behavior to the gel in solution. The viscosity of a BAC crosslinked microgel suspension was also measured under reducing conditions. The viscosity of the microgel suspension reduced with time, due to the breakage of the disulfide bonds in the crosslinkers. PMID:17550282

Bajomo, Michael; Steinke, Joachim H G; Bismarck, Alexander

2007-07-26

68

Nanopore density effect of polyacrylamide gel plug on electrokinetic ion enrichment in a micro-nanofluidic chip  

NASA Astrophysics Data System (ADS)

In this paper, the nanopore density effect on ion enrichment is quantitatively described with the ratio between electrophoresis flux and electroosmotic flow flux based on the Poisson-Nernst-Planck equations. A polyacrylamide gel plug is integrated into a microchannel to form a micro-nanofluidic chip. With the chip, electrokinetic ion enrichment is relatively stable and enrichment ratio of fluorescein isothiocyanate can increase to 600-fold within 120 s at the electric voltage of 300 V. Both theoretical research and experiments show that enrichment ratio can be improved through increasing nanopore density. The result will be beneficial to the design of micro-nanofluidic chips.

Wang, Jun-yao; Xu, Zheng; Li, Yong-kui; Liu, Chong; Liu, Jun-shan; Chen, Li; Du, Li-qun; Wang, Li-ding

2013-07-01

69

Studies on Miltenberger class III, V, Mv and Mk red cells. I. Sodium-dodecylsulfate polyacrylamide gel electrophoretic investigations.  

PubMed

The glycoproteins in erythrocyte membrane from individuals exhibiting the rare alleles at the MNSs blood group locus Miltenberger (Mi-) III, V, Mv and Mk were studied by sodium-dodecylsulfate polyacrylamide gel electrophoretic techniques. The results suggest that the genes Mi-III and -V give rise to the formation of Ss sialoglycoproteins whose electrophoretic mobilities are altered. The Mi-V alteration is additionally associated with a decreased MN glycoprotein content. The allele Mv leads to a decreased Ss glycoprotein content. Data on ordinary Mk and Mk/Mi-III red cells suggest that the gene complex Mk does not give rise to the synthesis of Ss glycoprotein. PMID:687840

Dahr, W; Longster, G; Uhlenbruck, G; Schumacher, K

1978-09-15

70

Typing and subtyping of haptoglobin from native serum using disc gel electrophoresis in alkaline buffer: application to routine screening.  

PubMed

A method with which the six common phenotypes of human haptoglobin can be identified using unseparated serum is described. In contrast to other reported methods, both typing and subtyping of haptoglobin can be performed by polyacrylamide gel electrophoresis in alkaline buffer using 0.1-4.0 microliter of native serum with hemoglobin added. Haptoglobin-hemoglobin complexes are visualized by their peroxidase activity using benzidine and barium peroxide. This relatively inexpensive and fast method seems particularly well suited for the typing and subtyping of haptoglobin from minute amounts in large series of sera and other body fluids and thus may be useful in medical genetics and forensic medicine. PMID:6496936

Linke, R P

1984-08-15

71

A Review of the Partly Hydrolyzed Polyacrylamide Cr(III) Acetate Polymer Gels  

Microsoft Academic Search

Enhanced oil recovery techniques and optimization of the oil field operations are currently of great importance for the oil and gas industry, which has an aggressive approach to research and technological modernization in order to supply the demand for conventional oil. The versatility of partly hydrolyzed polyacrylamide Cr(III) acetate has placed it as one of the most widely used polymer

S. M. Vargas-Vasquez; L. B. Romero-Zerón

2008-01-01

72

Detection of actin-binding proteins in human platelets by 125I-actin overlay of polyacrylamide gels  

PubMed Central

Actin-binding proteins have been identified in human platelets with a gel-overlay technique that uses 125I-G-actin. Platelet proteins were separated on SDS polyacrylamide gels using the buffer system of Laemmli (1970, Nature [Lond.] 227:680-685). The proteins were fixed in the gels with methanol-acetic acid, the SDS was washed out, and the proteins were renatured. The gels were incubated with 125I-G-actin from rabbit skeletal muscle that was radiolabeled with 125I according to the method of Bolton and Hunter (1973, Biochem. J. 133:529-538) and has been shown to retain biological activity. After nonspecifically bound radioactivity was washed out, gels were dried and processed for autoradiography. The 125I-G-actin binds to several proteins in human platelets, platelet extracts, and the particulate fraction. Control experiments demonstrate that the 125I-G-actin can be displaced by use of increasing amounts of unlabeled actin, that the binding is stable to 0.6 M NaCl, and that preheating the 125I-G-actin to 90 degrees C for 3 min eliminates all binding. Prominent 125I-G-actin-binding activities were present at Mr 90,000 and 40,000. The binding to the 90,000 Mr protein appears to be at least partially Ca++ sensitive, whereas the binding to the 40,000 Mr protein does not. 125I-G-actin bound to proteins in the SDS gels can be fixed in situ and compared directly with the stained gel. This technique should prove generally useful in identification and purification of some actin-binding proteins from cells and tissues. PMID:6793603

1981-01-01

73

Electrophoretic Transfer from Polyacrylamide Gel to Nitrocellulose Sheets, a New Method To Characterize Multilocus Enzyme Genotypes of Klebsiella Strains  

PubMed Central

A new method for multilocus enzyme electrophoresis, based on electrophoretic transfers to nitrocellulose after polyacrylamide-agarose gel electrophoresis was explored. Electrophoretic separation was performed on 1-mm-thick slab gels with 6-?l samples of bacterial extracts and was followed by serial 5-min consecutive transfers. The transferability of 19 metabolic enzymes of Klebsiella strains was studied and allowed the simultaneous examination of one enzyme in the separation gel and at least five enzymes on nitrocellulose sheets. The resolution of enzyme bands was increased on nitrocellulose; thus, well-separated bands were recorded for nucleoside phosphorylase, peptidase, and phosphoglucose isomerase whereas their mobility variants could not be clearly distinguished in the separation gel because of stain diffusion. The study of genetic relationships of 42 strains of Klebsiella pneumoniae and 24 strains of Klebsiella oxytoca demonstrated the reliability of the method, since clustering analysis of electrophoretic types, based on electrophoretic polymorphism of 10 metabolic enzymes, showed two main clusters well correlated with the two species. The 57 electrophoretic types described confirm the usefulness of the method for the study of genetic relationships between closely related strains. Images PMID:16349155

Combe, Marie-Laure; Pons, Jean-Louis; Sesboue, Richard; Martin, Jean-Pierre

1994-01-01

74

Competitive adsorption of bovine serum albumin and lysozyme on characterized calcium phosphates by polyacrylamide gel electrophoresis method.  

PubMed

Characterizations of hydroxyapatite (HA), biphasic calcium phosphate (BCP) and beta tricalcium phosphate (beta-TCP) ceramic particles were carried out using X-ray diffusion (XRD), Scanning electron micrograph (SEM), Particle Sizer and Zeta potential analyzer. Competitive adsorption of bovine serum albumin (BSA) and lysozyme (LSZ) on the three calcium phosphates were investigated by polyacrylamide gel electrophoresis (PAGE) method. The results showed that HA, BCP and beta-TCP ceramic particles with irregular shapes and similar size distributions all had negative surface net charges in pH7.4 phosphate buffered saline (PBS) solution and exhibited alike behaviors of BSA and LSZ adsorption. LSZ had higher affinity for calcium phosphate ceramics than BSA and its adsorption on them didn't be almost influenced by the increasing of BSA concentration in the solution. Electrostatic interaction played an important role on the competitive adsorption of BSA and LSZ on the surface of calcium phosphate ceramic particles. PMID:17619993

Zhu, X D; Fan, H S; Zhao, C Y; Lu, J; Ikoma, T; Tanaka, J; Zhang, X D

2007-11-01

75

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

76

Definition of Mycobacterium tuberculosis Culture Filtrate Proteins by Two-Dimensional Polyacrylamide Gel Electrophoresis, N-Terminal Amino Acid Sequencing, and Electrospray Mass Spectrometry  

Microsoft Academic Search

A number of the culture filtrate proteins secreted by Mycobacterium tuberculosis are known to contribute to the immunology of tuberculosis and to possess enzymatic activities associated with pathogenicity. However, a complete analysis of the protein composition of this fraction has been lacking. By using two-dimensional polyacrylamide gel electrophoresis, detailed maps of the culture filtrate proteins of M. tuberculosis H37Rv were

MICHAEL G. SONNENBERG; JOHN T. BELISLE

1997-01-01

77

Polyacrylamide Gel Photopatterning enables Automated Protein Immunoblotting in a Two-dimensional Microdevice  

E-print Network

). Streptavidin-acrylamide (SA) was purchased from Invitrogen (Carlsbad, CA). Premixed 10� Tris­glycine native dodecyl sulfate (SDS), Cetyl trimethylammonium bromide (CTAB), 30% acrylamide/bis- acrylamide (29 with a 6%T precursor solution (including streptavidin-acrylamide) to UV excitation (~13 mW/cm2 ) for 8 min

Herr, Amy E.

78

Normoxic polyacrylamide gel doped with iodine: response versus X-ray energy.  

PubMed

The basis of Synchrotron Stereotactic Radio-Therapy (SSRT) is the incorporation of high atomic number atoms (iodine, for example) into the tumour mass followed by an irradiation with a monochromatic, low energy, X-ray beam from a synchrotron source. The purpose of the present study was to determine whether polymer gel dosimetry could be used to measure the enhancement of absorbed energy induced by the iodine in the media. We have used a standard nPAG formulation, loaded with NaI and the irradiations were performed either with monochromatic X-rays at the ESRF medical beamline or with a conventional 6 MV X-ray beam from a linear accelerator at the Grenoble University Hospital. We observed sensitivity increase with iodine loaded gels irradiated at low energies, in good agreement with the theoretical iodine dose-enhancement. As expected, the response of the iodine-doped polymer gel was not increased after irradiation with mega-voltage X-rays. We demonstrate in this study that polymer gel dosimeters can be used for measuring dose-enhancement due to iodine presence in SSR treatment. PMID:18602237

Gastaldo, Jérôme; Boudou, Caroline; Lamalle, Laurent; Troprès, Irène; Corde, Stéphanie; Sollier, Albéric; Rucka, Günther; Elleaume, Hélène

2008-12-01

79

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. PMID:22816378

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

2012-01-01

80

Detection of N-glycans on small amounts of glycoproteins in tissue samples and sodium dodecyl sulfate-polyacrylamide gels.  

PubMed

N-linked glycans harbored on glycoproteins profoundly affect the character of proteins by altering their structure or capacity to bind to other molecules. Specific knowledge of the role of N-glycans in these changes is limited due to difficulties in identifying precise carbohydrate structures on a given glycoprotein, which arises from the large amounts of glycoprotein required for N-glycan structural determination. Here, we refined a simple method to purify and detect trace amounts of N-glycans. During the N-glycan purification step, most contaminants were removed by two kinds of columns: a graphite carbon column and a cellulose column. N-Glycans were identified with a three-dimensional high-performance liquid chromatography (HPLC) system. Using our method, a global analysis of N-glycans from human muscle biopsy samples and mouse brain sections was possible. By combining sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with our method, we refined analytical procedures for N-glycans from SDS-PAGE gels using hydrazinolysis to achieve a high N-glycan recovery rate. N-Glycans on as little as 1 ?g of the target protein transferrin or immunoglobulin G (IgG) were easily detected. These methods allowed us to efficiently determine glycoprotein N-glycans at picomole (pmol) levels. PMID:22369894

Yoshimura, Takeshi; Yamada, Gen; Narumi, Mai; Koike, Takako; Ishii, Akihiro; Sela, Ilan; Mitrani-Rosenbaum, Stella; Ikenaka, Kazuhiro

2012-04-15

81

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 PMID:16345514

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

1980-01-01

82

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

83

Ultrasensitive Detection of Unstained Proteins in Acrylamide Gels by Native UV Fluorescence  

E-print Network

Ultrasensitive Detection of Unstained Proteins in Acrylamide Gels by Native UV Fluorescence Jan, Germany Visualization of proteins inside acrylamide and other gels usually relies on different staining methods. To omit the protein-staining procedure, we visualized unstained pro- teins inside acrylamide gels

Bielefeld, Universität

84

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

85

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

86

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

87

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

88

A vertical submarine electrophoresis apparatus for polyacrylamide minigels.  

PubMed

A vertical submarine electrophoresis apparatus for use with minislab polyacrylamide gels is described. The design allows polyacrylamide gels to be run with the same ease and convenience that agarose gels are run with horizontal submarine apparatuses. The vertical submarine features a single buffer chamber with a restriction between the upper and the lower portions of the chamber. Acrylamide gels, cast between 9 X 10-cm glass slides, are inserted into the restriction and are completely immersed in buffer. Thus, current flows primarily through the gel itself, but some current flows through the buffer in the restriction surrounding the gel. Because water-tight separation of buffer chambers is not necessary, time-consuming and/or expensive procedures such as sealing with agarose or using fragile notched glass plates are eliminated. The apparatus can be set up to run a gel in less than 30 s. It is versatile in that gels of varying thickness (0.5, 0.8, 1.5, and 3 mm) can be run on a single apparatus. The apparatus has been used for sodium dodecyl sulfate gels, low ionic strength native gels for nucleoprotein complexes, and composite acrylamide-agarose gels. PMID:2339782

Spiker, S

1990-03-01

89

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

90

Fluorographic detection of tritiated glycopeptides and oligosaccharides separated on polyacrylamide gels: analysis of glycans from Dictyostelium discoideum glycoproteins  

SciTech Connect

Previous workers have shown that oligosaccharides and glycopeptides can be separated by electrophoresis in buffers containing borate ions. However, normal fluorography of tritium-labeled structures cannot be performed because the glycans are soluble and can diffuse during equilibration with scintillants. This problem has been circumvented by equilibration of the gel with 2,5-diphenyloxazole (PPO) prior to electrophoresis. The presence of PPO in the gel during electrophoresis does not alter mobility of the glycopeptides and oligosaccharides. After electrophoresis, the gel is simply dried and fluorography performed. This allows sensitive and precise comparisons of labeled samples in parallel lanes of a slab gel and, since mobilities are highly reproducible, between different gels. The procedure is preparative in that after fluorography the gel bands can be quantitatively eluted for further study, without any apparent modification by the procedure. In this report, the procedure is illustrated by fractionation of both neutral and anionic glycopeptides produced by the cellular slime mold Dictyostelium discoideum.

Prem Das, O.; Henderson, E.J.

1986-11-01

91

Coupling sodium dodecyl sulfate-capillary polyacrylamide gel electrophoresis with matrix-assisted laser desorption ionization time-of-flight mass spectrometry via a poly(tetrafluoroethylene) membrane.  

PubMed

Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) is a fundamental analytical technique for proteomic research, and SDS-capillary gel electrophoresis (CGE) is its miniaturized version. Compared to conventional slab-gel electrophoresis, SDS-CGE has many advantages such as increased separation efficiency, reduced separation time, and automated operation. SDS-CGE is not widely accepted in proteomic research primarily due to the difficulties in identifying the well-resolved proteins. MALDI-TOF-MS is an outstanding platform for protein identifications. Coupling the two would solve the problem but is extremely challenging because the MS detector has no access to the SDS-CGE-resolved proteins and the SDS interferes with MS detection. In this work we introduce an approach to address these issues. We discover that poly(tetrafluoroethylene) (PTFE) membranes are excellent materials for collecting SDS-CGE-separated proteins. We demonstrate that we can wash off the SDS bound to the collected proteins and identify these proteins on-membrane with MALDI-TOF-MS. We also show that we can immunoblot and Coomassie-stain the proteins collected on these membranes. PMID:21309548

Lu, Joann J; Zhu, Zaifang; Wang, Wei; Liu, Shaorong

2011-03-01

92

Detection of metals in proteins by means of polyacrylamide gel electrophoresis and laser ablation-inductively coupled plasma-mass spectrometry: application to selenium.  

PubMed

The capabilities of laser ablation-inductively coupled plasma-mass spectrometry for the detection of trace elements in a gel after gel electrophoresis were systematically studied. Figures of merit, such as limit of detection, linearity, and repeatability, were evaluated for various elements (Li, V, Cr, Mn, Ni, Cu, Zn, As, Se, Mo, Pd, Ag, Cd, Pt, Tl, Pb). Two ablation strategies were followed: single hole drilling, relevant for ablation of spots after two-dimensional (2-D) separations, and ablation with translation, i.e., on a line, relevant for one-dimensional (1-D) separations. This technique was applied to the detection of selenoproteins in red blood cells extracts after a 1-D separation (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) and the detection of selenium-containing proteins in yeast after 2-D electrophoresis (2-DE). The detection procedure was further improved by using the dynamic reaction cell technology, which allowed the removal of the Ar_2(+) interference and hence the use of the most abundant Se isotope, (80)Se. Reaction gases were compared (methane, carbon monoxide, ammonia, oxygen and the combination of argon (collision gas) and hydrogen (reaction gas)). In each instance, the reaction cell parameters were optimized in order to obtain the lowest detection limit for Se (as (80)Se(+), (82)Se(+) or (77)Se(+); and as (80)Se(16)O(+), (82)Se(16)O(+) or (77)Se(16)O(+) with O(2) as the reaction gas). Carbon monoxide was found to offer the best performance. The detection limit with the use of DRC and He as transport gas was 0.07 microg Se g(-1) gel with single hole drilling and 0.15 microg Se g(-1) gel for ablation with translation. PMID:14595676

Chéry, Cyrille C; Günther, Detlef; Cornelis, Rita; Vanhaecke, Frank; Moens, Luc

2003-10-01

93

Characterization of Sm14 related components in different helminths by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting analysis.  

PubMed

Sm14 was the first fatty acid-binding protein homologue identified in helminths. Thereafter, members of the same family were identified in several helminth species, with high aminoacid sequence homology between them. In addition, immune crossprotection was also reported against Fasciola hepatica infection, in animals previously immunized with the Schistosoma mansoni vaccine candidate, r-Sm14. In the present study, data on preliminary sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting analysis of nine different helminth extracts focusing the identification of Sm14 related proteins, is reported. Out of these, three extracts - Ascaris suum (males and females), Echinostoma paraensei, and Taenia saginata - presented components that comigrated with Sm14 in SDS-PAGE, and that were recognized by anti-rSm14 policlonal serum, in Western blotting tests. PMID:12426606

Thaumaturgo, Nilton; Vilar, Mônica Magno; Edelenyi, Ricardo; Tendler, Miriam

2002-01-01

94

Light Scattering Induced Giant RedShift in Photoluminescence from CdTe Quantum Dots Encapsulated in Polyacrylamide Gel Nanospheres  

Microsoft Academic Search

The photoluminescence emission from CdTe quantum dots embedded in hydrogel nanospheres based on poly(N-isopropylacrylamide) (PNIPAM) polymer is observed to be modified by the random light scattering within the colloidal medium. Photoluminescence emission from CdTe quantum dots of various size has been observed making the gel fluorescent. The optical properties of the quantum dots entrapped within the gel microspheres can be

Brett W. Garner; Tong Cai; Zhibing Hu; Moon Kim; Arup Neogi

2009-01-01

95

Light Scattering Induced Giant Red-Shift in Photoluminescence from CdTe Quantum Dots Encapsulated in Polyacrylamide Gel Nanospheres  

NASA Astrophysics Data System (ADS)

The photoluminescence emission from CdTe quantum dots embedded in hydrogel nanospheres based on poly(N-isopropylacrylamide) (PNIPAM) polymer is observed to be modified by the random light scattering within the colloidal medium. Photoluminescence emission from CdTe quantum dots of various size has been observed making the gel fluorescent. The optical properties of the quantum dots entrapped within the gel microspheres can be modified due to change in refractive index, volume density of the surrounding hydrogel medium. A red-shift of ?100 nm has been observed from quantum dots emitting in the green wavelength region as the cell length is increased. This shift is due to secondary scattering and energy transfer induced by the larger scattering cross-section within the medium which results in a re-excitation of larger sized quantum dots.

Garner, Brett W.; Cai, Tong; Hu, Zhibing; Kim, Moon; Neogi, Arup

2009-07-01

96

Direct detection of an antimicrobial peptide of Pediococcus acidilactici in sodium dodecyl sulfate-polyacrylamide gel electrophoresis  

Microsoft Academic Search

Summary An SDS-PAGE technique is described that allows identification of the antimicrobial activity of a peptide secreted by a strain ofPediococcus acidilactici. This peptide has an antimicrobial property against several baeteria associated with food. This technique enables detection of the specific peptide (or protein) band(s) associated with the inhibitory effect which can then be eluted from the gel for further

Arun K. Bhunia; M. C. Johnson; Bibek Ray

1987-01-01

97

Structural analysis of protein complexes with sodium alkyl sulfates by small-angle scattering and polyacrylamide gel electrophoresis.  

PubMed

Small-angle X-ray (SAXS) and neutron (SANS) scattering is used to probe the structure of protein-surfactant complexes in solution and to correlate this information with their performance in gel electrophoresis. Proteins with sizes between 6.5 to 116 kDa are denatured with sodium alkyl sulfates (SC(x)S) of variable tail lengths. Several combinations of proteins and surfactants are analyzed to measure micelle radii, the distance between micelles, the extension of the complex, the radius of gyration, and the electrophoretic mobility. The structural characterization shows that most protein-surfactant complexes can be accurately described as pearl-necklace structures with spherical micelles. However, protein complexes with short surfactants (SC(8)S) bind with micelles that deviate significantly from spherical shape. Sodium decyl (SC(10)S) and dodecyl (SC(12)S, more commonly abbreviated as SDS) sulfates result in the best protein separations in standard gel electrophoresis. Particularly, SC(10)S shows higher resolutions for complexes of low molecular weight. The systematic characterization of alkyl sulfate surfactants demonstrates that changes in the chain architecture can significantly affect electrophoretic migration so that protein-surfactant structures could be optimized for high resolution protein separations. PMID:21182321

Ospinal-Jiménez, Mónica; Pozzo, Danilo C

2011-02-01

98

Variation and Genomic Localization of Genes Encoding DROSOPHILA MELANOGASTER Male Accessory Gland Proteins Separated by Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis  

PubMed Central

Accessory gland proteins from Drosophila melanogaster males have been separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis into nine major bands. When individual males from 175 strains were examined, considerable polymorphism for nearly one-half of the major protein bands was seen, including null alleles for three bands. Variation was observed not only among long-established laboratory strains but also among stocks recently derived from natural populations. There was little difference in the amount of variation between P and M strains, indicating that P element mutagenesis is not a factor producing the variation. Codominant expression of variants for each of five bands was found in heterozygotes, suggesting structural gene variation and not posttranslational modification variation. Stocks carrying electrophoretic variants of four of the major proteins were used to map the presumed structural genes for these proteins; the loci were found to be dispersed on the second chromosome. Since males homozygous for variant proteins were fertile, the polymorphism seems to have little immediate effect on successful sperm transfer. We propose that a high degree of polymorphism can be tolerated because these proteins play a nutritive rather than enzymatic role in Drosophila reproduction. PMID:3095182

Whalen, Michael; Wilson, Thomas G.

1986-01-01

99

A rapid method of species identification of wild chironomids (Diptera: Chironomidae) via electrophoresis of hemoglobin proteins in sodium dodecyl sulfate polyacrylamide gel (SDS-PAGE).  

PubMed

Studying aquatic benthic macroinvertebrates (BMIs) in the field requires accurate taxonomic identification, which can be difficult and time consuming. Conventionally, head capsule morphology has been used to identify wild larvae of Chironomidae. However, due to the number of species and possible damage and/or deformity of their head capsules, another supporting approach for identification is needed. Here, we provide hemoglobin (Hb) protein in hemolymph of chironomids as a new biomarker that may help resolve some of the ambiguities and difficulties encountered during taxonomic identification. Chironomids collected from two locations in Maine and New Jersey, USA were identified to the genus level and in some cases to the species-level using head capsule and body morphologies. The head capsule for a particular individual was then associated with a corresponding Hb protein profile generated from sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Distinct Hb profiles were observed from one group (Thienemannimyia) and four genera (Chironomus, Cricotopus, Dicrotendipes, and Glyptotendipes) of chironomids. Several species were polymorphic, having more than one Hb profile and/or having bands of the same size as those of other species. However, major bands and the combination of bands could distinguish individuals at the genus and sometimes species-level. Overall, this study showed that Hb profiles can be used in combination with head capsule morphology to identify wild chironomids. PMID:24923437

Oh, J T; Epler, J H; Bentivegna, C S

2014-10-01

100

Fabrication of a novel light emission material AlFeO3 by a modified polyacrylamide gel route and characterization of the material  

NASA Astrophysics Data System (ADS)

AlFeO3 powders have been prepared by a modified polyacrylamide gel method and their thermal expansion and photoluminescence properties have been studied for the first time. The phase, morphology and thermal expansion behavior of as-prepared samples were analyzed via X-ray diffraction (XRD), Scanning electron microscope (SEM), and thermal dilatometer. XRD analysis indicates that the as-synthesized AlFeO3 has the same structure as ?-Fe2O3 without the presence of any other impurities. SEM observation shows that the morphology of AlFeO3 powder is significantly dependent on the sintering temperature. The thermal expansion and differential scanning calorimetry (DSC) curves of AlFeO3 sample analysis indicates that a phase transition near 700 °C. The crystal growth mechanisms, coordination mechanisms, phase transformation process and luminescence mechanisms of AlFeO3 have been discussed on the basis of the experimental results. The blue light emission at 2.76 eV is due to intracenter 4T1 ? 6A1 transitions in Fe3+ ions.

Wang, Shi-Fa; Zhang, Chuanfei; Sun, Guangai; Chen, Bo; Xiang, Xia; Wang, Hong; Fang, Leiming; Tian, Qiang; Ding, Qingping; Zu, XiaoTao

2013-12-01

101

Comprehensive analysis of collagen metabolism in vitro using (4(/sup 3/H))/(/sup 14/C)proline dual-labeling and polyacrylamide gel electrophoresis  

SciTech Connect

A method to simultaneously quantify the production, secretion, and prolyl hydroxylation of individual types of collagen in cell culture samples has been developed. Collagens were biosynthetically labeled with a mixture of (/sup 14/C)proline and (4-/sup 3/H)proline. The labeled collagens were isolated and their component alpha-chains were resolved by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. Migration of the collagen alpha-chains was determined by fluorography, and radioactivity in excised bands was quantified by scintillation counting. (/sup 14/C)Proline labeling of collagen chains was used to determine the production and secretion of the different types of collagen. The ratios of the component alpha 1(I) and alpha 2(I) chains of type I collagen were also determined in this way. Prolyl hydroxylation of collagen alpha-chains was readily determined by measurement of their /sup 3/H:/sup 14/C ratios. Following 4-hydroxylation, /sup 3/H was lost from the (4-3H)proline with alteration of this ratio. This dual-labeling method is suitable for the comprehensive analysis of collagen metabolism in multiple samples.

Bateman, J.F.; Harley, V.; Chan, D.; Cole, W.G.

1988-01-01

102

Evaluation of ram semen quality using polyacrylamide gel instead of cervical mucus in the sperm penetration test.  

PubMed

Fertility is a very complex biological function that depends on several properties of the spermatozoa, including sperm motility. Two objectives are analyzed in this study: (1) Replace the cervical mucus by a synthetic medium in a sperm penetration test, and (2) evaluating the results of this test objectively analyzing the sperm number that migrates. In experiment 1, we have tested eight concentrations of acrylamide (1%-2%). Rheological properties of media were analyzed. The plastic straws, loaded with acrylamide, were placed vertically on the semen sample tube for 15 min at 39 °C. After, the acrylamides were placed, by segments of 5 mm, into wells of a 24-well plate, dyed with Hoechst 33342 and the number of spermatozoa were calculated by automated microscopy analysis. The 1.55% and 1.6% acrylamide gel showed a number of spermatozoa emigrating closer to that seen with natural mucus. In experiment 2, we applied the sperm penetration in acrylamide 1.6% and 1.55% using fresh semen and cooled semen at 15 °C and 5 °C. The spermatozoa counts were performed for each segment of 10 mm. Semen chilled at 15 °C presented intermediate values of sperm counts in comparison with fresh semen (higher) and 5 °C chilled semen. The sperm counts do not differ between acrylamides but the rheological properties of acrylamide 1.6% were more similar to those of the natural cervical mucus. In experiment 3, we have observed significant correlations between the number of spermatozoa and several sperm quality parameters (positive: progressive motility and velocity according to the straight path; negative: damaged acrosomes and apoptotic cells) in 1.6% acrylamide media. We conclude that the size of the cell subpopulation, objectively calculated, that migrate beyond 20 mm in 0.5-mL straws filled with acrylamide is a useful parameter in ram sperm quality assessment and further studies are needed to evaluate its relationship with field fertility. PMID:22289220

Martínez-Rodríguez, C; Alvarez, M; Ordás, L; Chamorro, C A; Martinez-Pastor, F; Anel, L; de Paz, P

2012-05-01

103

Sinking particle properties from polyacrylamide gels during the KErguelen Ocean and Plateau compared Study (KEOPS): Zooplankton control of carbon export in an area of persistent natural iron inputs in the Southern Ocean  

Microsoft Academic Search

The Kerguelen ocean and plateau compared study (KEOPS) examined the origin of elevated phytoplankton biomass in naturally iron-fertilized waters over the Kerguelen plateau during midsummer (January-February 2005). We report sinking particle characteristics determined from image analysis of thousands of individual particles collected in viscous polyacrylamide gels placed in free-drifting sediment traps at two sites: a high phytoplankton biomass site over

F. Ebersbach; T. W. Trull

2008-01-01

104

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

105

Time-Resolved Raman and Polyacrylamide Gel Electrophoresis Observations of Nucleotide Incorporation and Misincorporation in RNA within a Bacterial RNA Polymerase Crystal.  

PubMed

The bacterial RNA polymerase (RNAP) elongation complex (EC) is highly stable and is able to extend an RNA chain for thousands of nucleotides. Understanding the processive mechanism of nucleotide addition requires detailed structural and temporal data for the EC reaction. Here, a time-resolved Raman spectroscopic analysis is combined with polyacrylamide gel electrophoresis (PAGE) to monitor nucleotide addition in single crystals of the Thermus thermophilus EC (TthEC) RNAP. When the cognate base GTP, labeled with (13)C and (15)N (*GTP), is soaked into crystals of the TthEC, changes in the Raman spectra show evidence of nucleotide incorporation and product formation. The major change is the reduction of *GTP's triphosphate intensity. Nucleotide incorporation is confirmed by PAGE assays. Both Raman and PAGE methods have a time resolution of minutes. There is also Raman spectroscopic evidence of a second population of *GTP in the crystal that does not become covalently linked to the nascent RNA chain. When this population is removed by "soaking out" (placing the crystal in a solution that contains no NTP), there are no perturbations to the Raman difference spectra, indicating that conformational changes are not detected in the EC. In contrast, the misincorporation of the noncognate base, (13)C- and (15)N-labeled UTP (*UTP), gives rise to large spectroscopic changes. As in the GTP experiment, reduction of the triphosphate relative intensity in the Raman soak-in data shows that the incorporation reaction occurs during the first few minutes of our instrumental dead time. This is also confirmed by PAGE analysis. Whereas PAGE data show *GTP converts 100% of the nascent RNA 14mer to 15mer, the noncognate *UTP converts only ?50%. During *UTP soak-in, there is a slow, reversible formation of an ?-helical amide I band in the Raman difference spectra peaking at 40 min. Similar to *GTP soak-in, *UTP soak-in shows Raman spectoscopic evidence of a second noncovalently bound *UTP population in the crystal. Moreover, the second population has a marked effect on the complex's conformational states because removing it by "soaking-out" unreacted *UTP causes large changes in protein and nucleic acid Raman marker bands in the time range of 10-100 min. The conformational changes observed for noncognate *UTP may indicate that the enzyme is preparing for proofreading to excise the misincorporated base. This idea is supported by the PAGE results for *UTP soak-out that show endonuclease activity is occurring. PMID:25584498

Antonopoulos, Ioanna H; Murayama, Yuko; Warner, Brittany A; Sekine, Shun-Ichi; Yokoyama, Shigeyuki; Carey, Paul R

2015-01-27

106

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

107

Extracellular Matrix Fibronectin Stimulates the Self-Assembly of Microtissues on Native Collagen Gels  

PubMed Central

Fibronectin is an adhesive glycoprotein that is polymerized into extracellular matrices via a tightly regulated, cell-dependent process. Here, we demonstrate that fibronectin matrix polymerization induces the self-assembly of multicellular structures in vitro, termed tissue bodies. Fibronectin-null mouse embryonic fibroblasts adherent to compliant gels of polymerized type I collagen failed to spread or proliferate. In contrast, addition of fibronectin to collagen-adherent fibronectin-null mouse embryonic fibroblasts resulted in a dose-dependent increase in cell number, and induced the formation of three-dimensional (3D) multicellular structures that remained adherent and well-spread on the native collagen substrate. An extensive fibrillar fibronectin matrix formed throughout the microtissue. Blocking fibronectin matrix polymerization inhibited both cell proliferation and microtissue formation, demonstrating the importance of fibronectin fibrillogenesis in triggering cellular self-organization. Cell proliferation, tissue body formation, and tissue body shape were dependent on both fibronectin and collagen concentrations, suggesting that the relative proportion of collagen and fibronectin fibrils polymerized into the extracellular matrix influences the extent of cell proliferation and the final shape of microtissues. These data demonstrate a novel role for cell-mediated fibronectin fibrillogenesis in the formation and vertical assembly of microtissues, and provide a novel approach for engineering complex tissue architecture. PMID:20673131

Sevilla, Carlos A.; Dalecki, Diane

2010-01-01

108

Residual tRNA secondary structure in 'denaturing' 8M urea/TBE polyacrylamide gels: effects on electrophoretic mobility and dependency on prior chemical modification of the tRNA.  

PubMed

Fifteen individual species of tRNA were treated with the chemical modifiers diethylpyrocarbonate, 50% aqueous hydrazine or hydrazine/3 M NaCl. Following purification of the chemically modified material on polyacrylamide gels containing 8 M urea, variant minor bands, in addition to the expected main band, were observed for 12 of the 15 tRNAs. Characterization of the content of chemically altered bases in material recovered from such bands indicated that tRNAs containing modified nucleotides in base-paired stems were excluded from the main band and present, often in enhanced amounts, in the minor variant bands. The persistence of residual secondary structure on 8 M urea gels run at 45 degrees C and the ability of chemically modified bases to alter electrophoretic mobilities warrant caution in designing and interpreting experiments in which chemically modified RNA is isolated on gels prior to further analysis. tRNA(Val) (VAC) was unique in that modified bases in non base-paired regions, according to the cloverleaf model of secondary structure, caused exclusion from the main band. Consequently, we propose a secondary structure for partially denatured tRNA(Val) (VAC), in which these bases are located in double stranded regions of the molecule. PMID:2349095

Hegg, L A; Thurlow, D L

1990-05-25

109

Detection of glycoproteins in polyacrylamide gels and on electroblots using Pro-Q Emerald 488 dye, a fluorescent periodate Schiff-base stain.  

PubMed

Pro-Q Emerald 488 glycoprotein stain reacts with periodic acid-oxidized carbohydrate groups, generating a bright green-fluorescent signal on glycoproteins. The stain permits detection of less than 5-18 ng of glycoprotein per band, depending upon the nature and the degree of protein glycosylation, making it roughly 8-16-fold more sensitive than the standard colorimetric periodic acid-Schiff base method using acidic fuchsin dye (pararosaniline). The green-fluorescent signal from Pro-Q Emerald 488 stain may optimally be visualized using charge-coupled device/xenon arc lamp-based imaging systems or 470-488 nm laser-based gel scanners. Though glycoprotein detection may be performed on transfer membranes, direct detection in gels avoids electroblotting and the specificity of staining is better in gels. After detecting glycoproteins with Pro-Q Emerald 488 dye, total protein profiles may subsequently be detected using SYPRO Ruby protein gel stain. Using computer-assisted registration techniques, images may then be merged to generate differential display maps. PMID:12601726

Hart, Courtenay; Schulenberg, Birte; Steinberg, Thomas H; Leung, Wai-Yee; Patton, Wayne F

2003-02-01

110

Application of both high-performance liquid chromatography combined with tandem mass spectrometry shotgun and 2-D polyacrylamide gel electrophoresis for streptococcal exoproteins gave reliable proteomic data.  

PubMed

Streptococci secrete a large number of exoproteins including virulence-associated toxins and enzymes. To construct a reliable database of streptococcal exoproteins, we integrated the results that were derived from two approaches: LC-based shotgun proteomic analysis and 2-D PAGE-based proteomic analysis. We identified 74 and 82 proteins by LC-based and gel-based analysis, respectively. Forty-five proteins were identified by both methods. In addition, two proteins, one identified by both methods and the other only by LC-based shotgun analysis, were newly annotated. We therefore found the importance of combinational analysis by the two methods for the construction of a more reliable database. PMID:21204954

Okamoto, Akira; Hasegawa, Tadao; Yamada, Keiko; Ohta, Michio

2011-02-01

111

Clinical Mycoplasma gallisepticum infection in multiplier breeder and meat turkeys caused by F strain: identification by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, restriction endonuclease analysis, and the polymerase chain reaction.  

PubMed

In February 1991, a flock of North Carolina multiplier breeder turkeys experienced respiratory signs, sinusitis, airsacculitis, and increased mortality. Mycoplasma gallisepticum (MG) was isolated, and appropriate control measures were initiated. Ultimately, this outbreak involved several breeder flocks of an integrated turkey production company before the last infected flock was identified in May 1991. During this time, MG was also isolated from a flock of commercial layer-type chickens raised as pullets in close proximity to the index turkey flock. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and restriction endonuclease analysis indicated that these isolates were identical to each other and to examples of the vaccinal F strain. Additionally, MG isolates from the affected turkey breeder and layer flocks were identified as MG F strain by use of an F strain-specific DNA probe and polymerase chain reaction. A separate outbreak of MG disease in several meat-turkey flocks of a Midwest producer/processor yielded isolates identified as F strain by the polymerase chain reaction. These studies demonstrated: 1) the utility of newer technologies for disease outbreak investigations; and 2) the potential of MG F strain to cause disease in breeder and meat turkeys under field conditions. PMID:8257382

Ley, D H; Avakian, A P; Berkhoff, J E

1993-01-01

112

Preparation of DNA-crosslinked polyacrylamide hydrogels.  

PubMed

Mechanobiology is an emerging scientific area that addresses the critical role of physical cues in directing cell morphology and function. For example, the effect of tissue elasticity on cell function is a major area of mechanobiology research because tissue stiffness modulates with disease, development, and injury. Static tissue-mimicking materials, or materials that cannot alter stiffness once cells are plated, are predominately used to investigate the effects of tissue stiffness on cell functions. While information gathered from static studies is valuable, these studies are not indicative of the dynamic nature of the cellular microenvironment in vivo. To better address the effects of dynamic stiffness on cell function, we developed a DNA-crosslinked polyacrylamide hydrogel system (DNA gels). Unlike other dynamic substrates, DNA gels have the ability to decrease or increase in stiffness after fabrication without stimuli. DNA gels consist of DNA crosslinks that are polymerized into a polyacrylamide backbone. Adding and removing crosslinks via delivery of single-stranded DNA allows temporal, spatial, and reversible control of gel elasticity. We have shown in previous reports that dynamic modulation of DNA gel elasticity influences fibroblast and neuron behavior. In this report and video, we provide a schematic that describes the DNA gel crosslinking mechanisms and step-by-step instructions on the preparation DNA gels. PMID:25226067

Previtera, Michelle L; Langrana, Noshir A

2014-01-01

113

Dynamic Light Scattering Studies on Photo Polymerized and Chemically Cross-linked Polyacrylamide Hydrogels  

NASA Astrophysics Data System (ADS)

Dynamic light scattering studies have been carried on (1) chemically cross-linked polyacrylamide (CCPA) gel (2) photopolymerized polyacrylamide (PPPA) gel and (3) PPPA gel with 93nm diameter polystyrene particles incorporated. All the three gels exhibited nonergodicity. The diffusion coefficients have been obtained by analyzing the initial time decay of intermediate scattering functions (ISF) for all the three gels. ISFs obtained for different scattering wave-vectors for pure gels showed collapse, whereas such a collapse was not observed for gel with particles, which imply a change in dynamics with incorporation of particles. The results are understood based on models that describe dynamics in gels.

Sabareesh, K. P. V.; Jena, Sidhartha S.; Tata, B. V. R.

2006-05-01

114

Recovering cDNA bands from differential display RT-PCR gels using a transparency film mask  

Microsoft Academic Search

We describe here the use of a transparency film as a mask for recovering bands from differential display reverse transcription-polymerase\\u000a chain reaction (DDRT-PCR) gels. This method represents a simple and rapid way to isolate the differentially expressed bands\\u000a from dried and nondried polyacrylamide, radioactive and nonradioactive, denaturing and native DDRT gels. A transparency film\\u000a is overlaid on the DDRT autoradiogram,

Jaquelline Germano de Oliveira; Paulo César Peregrino Feneira; Ema Geessien Kroon

1999-01-01

115

Cavitation Rheology of Polyacrylamide Hydrogels  

NASA Astrophysics Data System (ADS)

Cavitation rheology is a new characterization technique for the measurement of mechanical properties on small length scales, e.g. 10 -100 ?m, at any arbitrary location within a soft material. The technique involves growing a cavity at the tip of a syringe needle and monitoring the pressure of the cavity at the onset of instability. This critical pressure is directly related to the local modulus of the material. We used this technique to characterize the network mechanics of polyacrylamide hydrogel materials, a common material used in many biological applications. We compared the cavitation rheology results with that obtained from shear rheometry. This technique was used to investigate the rheological properties of gels with different dimensions and different moduli, which were obtained by varying initial monomer to water ratio. These results provide a quantitative foundation for the extension of this technique to in vivo characterization of biological tissues.

Kundu, Santanu; Zimberlin, Jessica; Crosby, Alfred

2008-03-01

116

Analysis of Mutant SOD1 Electrophoretic Mobility by Blue Native Gel Electrophoresis; Evidence for Soluble Multimeric Assemblies  

PubMed Central

Mutations in superoxide dismutase 1 (SOD1) cause familial forms of amyotrophic lateral sclerosis (fALS). Disease causing mutations have diverse consequences on the activity and half-life of the protein, ranging from complete inactivity and short half-life to full activity and long-half-life. Uniformly, disease causing mutations induce the protein to misfold and aggregate and such aggregation tendencies are readily visualized by over-expression of the proteins in cultured cells. In the present study we have investigated the potential of using immunoblotting of proteins separated by Blue-Native gel electrophoresis (BNGE) as a means to identify soluble multimeric forms of mutant protein. We find that over-expressed wild-type human SOD1 (hSOD1) is generally not prone to form soluble high molecular weight entities that can be separated by BNGE. For ALS mutant SOD1, we observe that for all mutants examined (A4V, G37R, G85R, G93A, and L126Z), immunoblots of BN-gels separating protein solubilized by digitonin demonstrated varied amounts of high molecular weight immunoreactive entities. These entities lacked reactivity to ubiquitin and were partially dissociated by reducing agents. With the exception of the G93A mutant, these entities were not reactive to the C4F6 conformational antibody. Collectively, these data demonstrate that BNGE can be used to assess the formation of soluble multimeric assemblies of mutant SOD1. PMID:25121776

Brown, Hilda H.; Borchelt, David R.

2014-01-01

117

Microchannel gel electrophoretic separation systems and methods for preparing and using  

DOEpatents

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 separation and quantifying analyte concentration based upon conventional polyacrylamide gel electrophoresis (PAGE). To retain biological activity of proteins and maintain intact immune complexes, native PAGE conditions were employed. Both direct (non-competitive) and competitive immunoassay formats are demonstrated in microchips for detecting toxins and biomarkers (cytokines, c-reactive protein) in bodily fluids (serum, saliva, oral fluids). Further, a description of gradient gels fabrication is included, in an effort to describe methods we have developed for further optimization of on-chip PAGE immunoassays. The described chip-based PAGE immunoassay method enables immunoassays that are fast (minutes) and require very small amounts of sample (less than a few microliters). Use of microfabricated chips as a platform enables integration, parallel assays, automation and development of portable devices.

Herr, Amy; Singh, Anup K; Throckmorton, Daniel J

2013-09-03

118

SURFEIT-1 gene analysis and two-dimensional blue native gel electrophoresis in cytochrome c oxidase deficiency.  

PubMed

Leigh syndrome, a progressive, often fatal, neurodegenerative disorder, is frequently associated with a deficiency in the activity of cytochrome c oxidase (COX), the last enzyme of the mitochondrial respiratory chain. In contrast to NADH:ubiquinone oxidoreductase and succinate dehydrogenase deficiencies, no mutations in nuclear genes encoding COX subunits have been identified thus far. Very recently, however, a Leigh syndrome complementation group has been identified which showed mutations in the SURFEIT-1 (SURF-1) gene. The results of a mutational detection study in 16 new randomly selected COX-deficient patients revealed a new mutation (C688T) in 2 patients and the earlier reported 845delCT mutation in 2 additional patients. In addition, we evaluated the diagnostic value of two-dimensional blue native gel electrophoresis. We show that this technique reveals distinct patterns of both fully and partially assembled COX complexes and is thereby capable of discrimination between COX-deficient SURF-1 and non-SURF-1-mutated patients. PMID:10558868

Coenen, M J; van den Heuvel, L P; Nijtmans, L G; Morava, E; Marquardt, I; Girschick, H J; Trijbels, F J; Grivell, L A; Smeitink, J A

1999-11-19

119

An Investigation of In Situ Gelation of a Polyacrylamide/Chromium(III) System in Porous Media  

E-print Network

Crosslinked polymer systems are used in enhanced oil recovery treatments. To further understand the behavior of such systems in porous media, the flow of a chromium(H[)-polyacrylamide gel system has been studied in unconsolidated porous media...

Montes, Antonio

1992-04-01

120

MP 33354 Pro-Q Sapphire 532 Oligohistidine Gel Stain  

E-print Network

MP 33354 Pro-Q® Sapphire 532 Oligohistidine Gel Stain Product Information Storage upon receipt: · 6­ polyacrylamide gel electrophoresis (PAGE) and Western blot analysis. With Molecular Probes Pro-Q® Sapphire 532­polyacrylamide gel, eliminating the need to blot the protein to a membrane (Figure 1, top). Pro-Q Sapphire 532

Lebendiker, Mario

121

Research Article Hydrophobically modified polyacrylamide  

E-print Network

capillary array electrophoresis instruments. Previous research in our group has shown that physically cross demonstrated the capability to sequence up to 1300 bases in approximately 2 h [3], and commercial instruments, N,N-dihexylacrylamide; HMPAM, hydrophobically modified polyacrylamide; IPA, isopropyl alcohol; LPA

Barron, Annelise E.

122

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.

Shahinpoor, Mohsen (Albuquerque, NM)

1995-01-01

123

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

124

Microrheology of cross-linked polyacrylamide networks  

NASA Astrophysics Data System (ADS)

Experiments investigating the local viscoelastic properties of a chemically cross-linked polymer are performed on polyacrylamide solutions in the sol and the gel regimes using polystyrene beads of varying sizes and surface chemistry as probes. The thermal motions of the probes are measured to obtain the elastic and viscous moduli of the sample. Probe dynamics are measured using two different dynamic light scattering techniques, diffusing wave spectroscopy (DWS) and quasielastic light scattering (QELS) as well as video-based particle tracking. Diffusing wave spectroscopy probes the short-time dynamics of the scatterers while QELS measures the dynamics at larger times. Video-based particle tracking provides a way to investigate the local environment of the individual probe particles. A combination of all the techniques results in a larger range of frequencies that can be probed compared to conventional bulk measurements while providing local information at the level of individual probes. A modified algebraic form of the generalized Stokes-Einstein equation is used to calculate the frequency-dependent moduli. A comparison of microrheological measurements with bulk rheology exhibits striking similarity, confirming the applicability of microrheology for chemically cross-linked polymeric systems.

Dasgupta, Bivash R.; Weitz, D. A.

2005-02-01

125

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

126

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

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. PMID:18539737

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

2008-08-01

127

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. PMID:18539737

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

2008-01-01

128

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

129

odium dodecyl sulfate polyacry-lamide gel electrophoresis (SDS-  

E-print Network

ana- lytical method to resolve separate components of a protein mixture. It is almost obligatory) and reducing agents to denature pro- teins (7). SDS binds strongly to proteins at an approximate ratio of 1 describes techniques and procedures as a guide for preparation of pro- tein samples for SDS-PAGE analysis

Lebendiker, Mario

130

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

131

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

132

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

133

A Simple Vertical Slab Gel Electrophoresis Apparatus.  

ERIC Educational Resources Information Center

Describes an inexpensive, easily constructed, and safe vertical slab gel kit used routinely for sodium dodecyl sulphate-polyacrylamide gel electrophoresis research and student experiments. Five kits are run from a single transformer. Because toxic solutions are used, students are given plastic gloves and closely supervised during laboratory…

Carter, J. B.; And Others

1983-01-01

134

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

135

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

136

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

137

Evaluation du potentiel radiosensibilisateur ou radioprotecteur/antioxydant de quelques composes selectionnes par dosimetrie par gel de polyacrylamide et dosimetre de Fricke, et utilisation de la filamentation par impulsion laser infrarouge fenitoseconde comme un nouveau et puissant faisceau pour la radiotherapie du cancer  

NASA Astrophysics Data System (ADS)

In radiation treatment, a sufficiently high radiation dose must be delivered to the tissue volumes containing the tumor cells while the lowest possible dose should be deposited in surrounding healthy tissue. We developed an original approach that is fast and easy to implement for the early assessment of the efficiency of radiation sensitizers and protectors. In addition, we characterized a new femtosecond laser pulse irradiation technique. We are able to deposit a considerable dose with a very high dose rate inside a well-controlled macroscopic volume without deposition of energy in front or behind the target volume. The radioprotective efficiency was measured by irradiation of the Fricke solution incorporating a compound under study and measuring the corresponding production of ferric ions G(Fe3+). The production of ferric ions is most sensitive to the radical species produced in the radiolysis of water. We studied experimentally and simulated with a full Monte-Carlo computer code the radiation-induced chemistry of Fricke/cystamine solutions. Results clearly indicate that the protective effect of cystamine originates from its radical-capturing ability, which allows this compound to compete with the ferrous ions for the various free radicals - especially ·OH radicals and H· atoms - formed during irradiation of the surrounding water. The sensitizing capacity of radiation sensitizers was measured by irradiation of a polyacrylamide gel (PAG) dosimeter incorporating a compound under study and measuring the corresponding increase in the gradient between spin-spin relaxation rate (R2) and absorbed dose. We measured an irradiation energy-dependent increase in R 2-dose sensitivity for halogenated compounds or a decrease for radioprotectors. Finally, we studied a novel laser irradiation method called "filamentation". We showed that this phenomenon results in an unprecedented deposition of energy and the dose rate thus achieved exceeds by orders of magnitude values previously reported for the most intense clinical radiotherapy systems. Moreover, the length of the dose-free entrance region was adjusted by selecting the duration of femtosecond laser pulses. In addition, we provided evidence that the biological damage caused by this irradiation was similar to other ionizing radiation sources. Keywords: Radiotherapy, radiosensitization, radioprotection, laser, filamentation, dosimetry.

Meesat, Ridthee

138

Biochemical characterization of Aspergillus oryzae native tannase and the recombinant enzyme expressed in Pichia pastoris.  

PubMed

In this study, the biochemical properties of the recombinant tannase from Aspegillus oryzae were compared with those of the native enzyme. Extracellular native tannase was purified from a commercial enzyme source. Recombinant tannase highly expressed in Pichia pastoris was prepared as an active extracellular protein. Purified native and recombinant tannases produced smeared bands with apparent molecular masses of 45-80 kDa and 45-75 kDa, respectively, by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. After N-deglycosylation, the native enzyme yielded molecular masses of 33 kDa and 30 kDa, whereas the recombinant enzyme yielded molecular masses of 34 kDa and 30 kDa. Purified native and recombinant tannases had an optimum pH of 4.0-5.0 and 5.0, respectively, and were stable up to 40°C. After N-deglycosylation, both enzymes exhibited reduced thermostability. Catalytic efficiencies of both purified enzymes were greater with natural substrates, such as (-)-catechin, (-)-epicatechin, and (-)-epigallocatechin gallates, than those with synthetic substrates, such as methyl, ethyl, and propyl gallates. However, there were no activities against the methyl esters of ferulic, p-coumaric, caffeic, and sinapic acids, which indicate feruloyl esterase activity, or the ethyl, propyl, and butyl esters of 4-hydroxybenzoic acid, which indicate paraben hydrolase activity. PMID:24856589

Mizuno, Toshiyuki; Shiono, Yoshihito; Koseki, Takuya

2014-10-01

139

Simulation of optical absorption and scattering in gel and egg white  

E-print Network

of this thesis is the calculation of these optical properties using polyacrylamide gel and egg white to achieve better control of the experimentation. The parameters are calculated from measurable physical quantities based on a particular theory of light... of the human protoplasm is fluid [19]. The percentage of water varies from tissue to tissue. Due to this vast variability in tissues, a hydropholic gel, the polyacrylamide gel, was chosen to simulate the laser ablation process in the biological tissue...

Kumbhani, Sujit Sumant

2012-06-07

140

Polyacrylamide Hydrogel Properties for Horticultural Applications  

Technology Transfer Automated Retrieval System (TEKTRAN)

Polyacrylamide (PAAm) hydrogels are commonly employed to ensure hydration of the growth media and minimize crop losses during the crop production and postproduction phases in horticulture. However, studies of the effect of these materials have shown that they have a minimal effect on crop life and q...

141

Cavitation Rheology and Fracture Behavior of Polyacrylamide Hydrogels  

NASA Astrophysics Data System (ADS)

Cavitation rheology is a new characterization technique for the measurement of mechanical properties on small length scales, e.g. 10 -1000 ?m, at any arbitrary location within a soft material. The technique involves growing a cavity at the tip of a syringe needle and monitoring the pressure of the cavity at the onset of instability. This critical pressure is directly related to the local modulus of the material. We used this technique to characterize the network mechanics of polyacrylamide hydrogel materials, a common material used in many biological applications. Gels with different moduli, which were obtained by varying initial monomer to water ratio, were investigated. As monomer concentration increased, a transition from stable cavity to fracture was observed. Applying scaling theory for gels, we modify the Lake-Thomas Theory for the fracture of crosslinked networks to relate the transition from cavitation to fracture in terms of molecular parameters. We anticipate this fundamental understanding of cavitation and fracture mechanism will be applicable to biological tissues, as well as the development of advanced soft materials

Kundu, Santanu; Crosby, Alfred

2009-03-01

142

21 CFR 173.10 - Modified polyacrylamide resin.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Modified polyacrylamide resin. 173.10...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SECONDARY...for Food Treatment § 173.10 Modified polyacrylamide resin....

2014-04-01

143

21 CFR 173.10 - Modified polyacrylamide resin.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Modified polyacrylamide resin...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED...PERMITTED IN FOOD FOR HUMAN CONSUMPTION Polymer...Treatment § 173.10 Modified polyacrylamide...

2012-04-01

144

21 CFR 173.10 - Modified polyacrylamide resin.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Modified polyacrylamide resin...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED...PERMITTED IN FOOD FOR HUMAN CONSUMPTION Polymer...Treatment § 173.10 Modified polyacrylamide...

2011-04-01

145

21 CFR 173.10 - Modified polyacrylamide resin.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Modified polyacrylamide resin...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED...PERMITTED IN FOOD FOR HUMAN CONSUMPTION Polymer...Treatment § 173.10 Modified polyacrylamide...

2013-04-01

146

21 CFR 173.10 - Modified polyacrylamide resin.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 true Modified polyacrylamide resin...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED...PERMITTED IN FOOD FOR HUMAN CONSUMPTION Polymer...Treatment § 173.10 Modified polyacrylamide...

2010-04-01

147

Conducting Polymer Electrodes for Gel Electrophoresis  

PubMed Central

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

148

Formation of composite polyacrylamide and silicone substrates for independent control of stiffness and strain  

PubMed Central

Cells that line major tissues in the body such as blood vessels, lungs and gastrointestinal tract experience deformation from mechanical strain with our heartbeat, breathing, and other daily activities. Tissues also remodel in both development and disease, changing their mechanical properties. Taken together, cells can experience vastly different mechanical cues resulting from the combination of these interdependent stimuli. To date, most studies of cellular mechanotransduction have been limited to assays in which variations in substrate stiffness and strain were not combined. Here, we address this technological gap by implementing a method that can simultaneously tune both substrate stiffness and mechanical strain. Substrate stiffness is controlled with different monomer and crosslinker ratios during polyacrylamide gel polymerization, and strain is transferred from the underlying silicone platform when stretched. We demonstrate this platform with polyacrylamide gels with elastic moduli at 6 kPa and 20 kPa in combination with two different silicone formulations. The gels remain attached with up to 50% applied strains. To validate strain transfer through the gels into cells, we employ particle-tracking methods and observe strain transmission via cell morphological changes. PMID:23287818

Simmons, Chelsey S.; Ribeiro, Alexandre J. S.; Pruitt, Beth L.

2013-01-01

149

Pore-Level Examination of Gel Destruction During Oil Flow  

E-print Network

Pore-Level Examination of Gel Destruction During Oil Flow R.S. Seright, SPE, New Mexico Petroleum-scale X-ray computed microtomography (XMT) images were obtained at a variety of oil (hexadecane(III)-acetate-hydrolyzed polyacrylamide (HPAM) gel]. For each pore in our image volume, we followed oil and water saturations

New York at Stoney Brook, State University of

150

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. PMID:24086559

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

2013-01-01

151

Impacts of Timing of Crosslinker Addition on Water Shut Off Polymer Gel Properties  

E-print Network

In preparation of gelant solution for making crosslinked polymer gels for water shutoff applications unpublished experiments plus chemical intuition suggest that, unless hydrolyzed polyacrylamide (HPAM) polymer is fully hydrated before addition...

Shriwal, Prashant

2012-07-16

152

A simple and cost-effective solid-phase protein nano-assay using polyacrylamide-coated glass plates.  

PubMed

A new solid-phase protein nano-assay is suggested for simple and sensitive estimation of protein content in sample buffers (a 1-?l sample is sufficient for analysis). The assay is different from conventional "on-filter" assays in that it uses inexpensive fully transparent polyacrylamide gel (PAAG)-coated glass plates as solid support and, thus, combines the convenience of "on-membrane" staining with the sensitivity and ease of documentation of "in-gel" staining (and, therefore, is especially suited for standard lab gel documentation systems). The PAAG plates assay is compatible with all dyes for in-gel protein staining. Depending on the sensitivity of the staining protocol, the assay can be used in macro-, micro-, and nano-assay formats. We also describe a low-cost two-component colloidal Coomassie brilliant blue G-250 (CBB G-250) staining protocol for fast quantitative visualization of proteins spotted on a PAAG plate (the detection limit is up to 2ng of proteins even when using a Nikon CoolPix digital camera and white light transilluminator instead of a gel scanner). The suggested colloidal CBB G-250 protocol could also be used for visualizing nano-amounts of proteins in polyacrylamide gels. The PAAG plate assay could be useful for proteomic applications and, in general, for all cases where a fast, sensitive, and easily documentable cost-effective solid-phase protein assay is required. PMID:25449300

Krajewski, Wladyslaw A

2015-02-01

153

Performance and Biocompatibility of Extremely Tough Alginate/Polyacrylamide Hydrogels  

PubMed Central

Although hydrogels now see widespread use in a host of applications, low fracture toughness and brittleness have limited their more broad use. As a recently described interpenetrating network (IPN) of alginate and polyacrylamide demonstrated a fracture toughness of ?9000 J/m2, we sought to explore the biocompatibility and maintenance of mechanical properties of these hydrogels in cell culture and in vivo conditions. These hydrogels can sustain a compressive strain of over 90% with minimal loss of Young's Modulus as well as minimal swelling for up to 50 days of soaking in culture conditions. Mouse mesenchymal stem cells exposed to the IPN gel-conditioned media maintain high viability, and although cells exposed to conditioned media demonstrate slight reductions in proliferation and metabolic activity (WST assay), these effects are abrogated in a dose-dependent manner. Implantation of these IPN hydrogels into subcutaneous tissue of rats for 8 weeks led to mild fibrotic encapsulation and minimal inflammatory response. These results suggest the further exploration of extremely tough alginate/PAAM IPN hydrogels as biomaterials. PMID:23896005

Darnell, Max; Sun, Jeong-Yun; Mehta, Manav; Johnson, Chris; Arany, Praveen; Suo, Zhigang

2013-01-01

154

Radio-synthesized polyacrylamide hydrogels for proteins release  

NASA Astrophysics Data System (ADS)

The use of hydrogels for biomedical purposes has been extensively investigated. Pharmaceutical proteins correspond to highly active substances which may be applied for distinct purposes. This work concerns the development of radio-synthesized hydrogel for protein release, using papain and bovine serum albumin as model proteins. The polymer was solubilized (1% w/v) in water and lyophilized. The proteins were incorporated into the lyophilized polymer and the hydrogels were produced by simultaneous crosslinking and sterilization using ?-radiation under frozen conditions. The produced systems were characterized in terms of swelling degree, gel fraction, crosslinking density and evaluated according to protein release, bioactivity and cytotoxicity. The hydrogels developed presented different properties as a function of polymer concentration and the optimized results were found for the samples containing 4-5% (w/v) polyacrylamide. Protein release was controlled by the electrostatic affinity of acrylic moieties and proteins. This selection was based on the release of the proteins during the experiment period (up to 50 h), maintenance of enzyme activity and the nanostructure developed. The system was suitable for protein loading and release and according to the cytotoxic assay it was also adequate for biomedical purposes, however this method was not able to generate a matrix with controlled pore sizes.

Ferraz, Caroline C.; Varca, Gustavo H. C.; Lopes, Patricia S.; Mathor, Monica B.; Lugão, Ademar B.

2014-01-01

155

Tailoring the mechanical properties of polyacrylamide-based hydrogels  

Microsoft Academic Search

Here, we studied the mechanical properties of polyacrylic acid-co-polyacrylamide (pAAc\\/pAAm) and polyacrylate-co-polyacrylamide (pNaAc\\/pAAm)-based hydrogels as a function of composition and total polymer content. While both polyacrylate and polyacrylic acid are weakly-charged polyelectrolytes with carboxylate side groups, they exhibit different behavior as copolymers with polyacrylamide. In swelling studies the highest degree of volumetric expansion occurs in the polyacrylate-rich hydrogels. Rheological measurements

Bryan A. Baker; Rebecca L. Murff; Valeria T. Milam

2010-01-01

156

Study of the effect of aluminum sulfate and polyacrylamide during clarification and filtration of a fluorite concentrate suspension  

Microsoft Academic Search

reagents as A12(SO4)3, technical polyacrylamide (PA) with degree of hydrolysis a = 12%, and technical PA artificially hydrolyzed in the presence of NaOH to a = 47% (PA gel, PAG). The florite flotation concentrates were obtained under laboratory conditions at the Central Research Institute of Tin, Antimony, and Mercury (TsNIIO1ovo) with the use of the collecting agent Flotol 7-9. The

A. P. Bimberekov

1993-01-01

157

Sol-gel transition of nanoparticles/polymer mixtures for sustained delivery of exenatide to treat type 2 diabetes mellitus.  

PubMed

The sol-gel transition of nanoparticles (NPs)/polymer mixture in aqueous medium was investigated for the sustained delivery of exenatide to treat type 2 diabetes mellitus. Exenatide-loaded multilayer NPs were prepared using a layer-by-layer approach which utilized the interaction between Pluronics and lipid bilayers as the main driving force for the construction of the multilayer. Pluronic F-127 was the polymer used, and it forms a gel at body temperature. Although the antidiabetic effects of exenatide-loaded multilayer NPs have been demonstrated previously in an animal model, in this work, the attempt was made to demonstrate the extended duration of antidiabetic effects, which was accomplished by localizing the exenatide-loaded NPs in muscular areas in the body through the gelation of Pluronic F-127. Transmittance electron microscopy and dynamic light scattering were used to examine the morphology of the multilayer NPs/polymer mixture. A change in the release pattern of exenatide was observed after gel formation at body temperature, and Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis was performed using native exenatide and a reference biomarker as control to observe whether exenatide extracted from the multilayer NPs and the multilayer NPs/Pluronic F-127 mixture degraded or not. We then observed the antidiabetic effect of exenatide-loaded multilayer NPs/Pluronic F-127 mixture by monitoring blood-glucose levels in db/db mice. In vitro and in vivo correlation was discussed regarding structural variation in the delivery vehicles. PMID:25152212

Oh, Keun Sang; Kim, Jae Yeon; Yoon, Byeong Deok; Lee, Minae; Kim, Heejoo; Kim, Michelle; Seo, Jae Hong; Yuk, Soon Hong

2014-11-01

158

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.

159

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

160

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

Code of Federal Regulations, 2012 CFR

...cationic polyacrylamide polymer denture adhesive. 872.3420 Section 872.3420...cationic polyacrylamide polymer denture adhesive. (a) Identification. A carboxymethylcellulose...cationic polyacrylamide polymer denture adhesive is a device composed of...

2012-04-01

161

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

Code of Federal Regulations, 2014 CFR

...cationic polyacrylamide polymer denture adhesive. 872.3420 Section 872.3420...cationic polyacrylamide polymer denture adhesive. (a) Identification. A carboxymethylcellulose...cationic polyacrylamide polymer denture adhesive is a device composed of...

2014-04-01

162

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

Code of Federal Regulations, 2013 CFR

...cationic polyacrylamide polymer denture adhesive. 872.3420 Section 872.3420...cationic polyacrylamide polymer denture adhesive. (a) Identification. A carboxymethylcellulose...cationic polyacrylamide polymer denture adhesive is a device composed of...

2013-04-01

163

Field demonstration of in situ grouting of radioactive solid waste burial trenches with polyacrylamide. [Polyacrylamide  

SciTech Connect

Demonstrations of in situ grouting with polyacrylamide were carried out on two undisturbed burial trenches and one dynamically compacted burial trench in Solid Waste Storage Area (SWSA) 6 at Oak Ridge National Laboratory (ORNL). The injection of polyacrylamide was achieved quite facilely for the two undisturbed burial trenches which were filled with grout, at typical pumping rates of 95 L/min, in several batches injected over several days. The compacted burial trench, however, failed to accept grout at more than 1.9 L/min even when pressure was applied. Thus, it appears that burial trenches, stabilized by dynamic compaction, have a permeability too low to be considered groutable. The water table beneath the burial trenches did not respond to grout injections indicating a lack of hydrologic connection between fluid grout and the water table which would have been observed if the grout failed to set. Because grout set times were adjusted to less than 60 min, the lack of hydrologic connection was not surprising. Postgrouting penetration testing revealed that the stability of the burial trenches was increased from 26% to 79% that measured in the undisturbed soil surrounding the trenches. In situ permeation tests on the grouted trenches indicated a significant reduction in hydraulic conductivity of the trench contents from a mean of 2.1 {times} 10{sup {minus}3} to 1.85 {times} 10{sup {minus}5} cm/s. Preliminary observations indicated that grouting with polyacrylamide is an excellent method for both improved stability and hydrologic isolation of radioactive waste and its incidental hazardous constituents.

Spalding, B.P.; Fontaine, T.A.

1990-01-01

164

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

165

Silver Staining of 2D Electrophoresis Gels Ccile Lelong, Mireille Chevallet, Sylvie Luche, Thierry Rabilloud  

E-print Network

1 Silver Staining of 2D Electrophoresis Gels Cécile Lelong, Mireille Chevallet, Sylvie Luche Cedex 9, France 1. Introduction Silver staining of polyacrylamide gels was introduced in 1979 by Switzer staining with Coomassie Blue. However, the first silver staining protocols were not trouble-free. High

Paris-Sud XI, Université de

166

Antioxidant effect of green tea on polymer gel dosimeter  

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

167

Native Americans  

NSDL National Science Digital Library

Native Americans are made up of many fascinating groups of people with multiple cultures. We will explore the main cultural areas of these groups. We will describe and compare some of these groups of people such as Eastern Woodlands, Plains, Great Basin, Southwestern, Arctic, Northwest, Incan, Aztec, and Mayan. We will also identify how these people maintain their cultural traditions today. We will explore each of this interesting cultures and take notes as we explore with individualized graphic organizers. Learning about Native Americans Woodland Tribes Great Plains Tribes Great Basin Native Americans Northwest Southwest Aztec, Mayans Inca BRAINTEASER The Inca Trail and Machu Picchu Glossary Links ...

Keller, Mrs.

2009-06-12

168

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

169

Simple miniaturized gel system for DNA sequence analysis.  

PubMed Central

A simple miniaturized gel system suitable for DNA sequencing is described. Small ultrathin polyacrylamide gels are cast, eight or more at a time, using standard microscope slides. Gels, ready to use, can be stored for approximately 2 weeks. Gels are run horizontally in a standard mini-agarose gel apparatus. Typical run times are 6-8 min. A novel sample loading system permits volumes of standard sequencing reactions as small as 0.1 microl to be analyzed. Sequencing ladders were visualized using 35S-labeled DNA by autoradiography and by colorimetric detection. Band resolution compares favorably with that of large gels. The methods introduced here serve as a step toward the miniaturization of DNA sequencing and are amenable to automated sample loading and detection. PMID:9421499

Stein, A; Hill, S A; Cheng, Z; Bina, M

1998-01-01

170

Mass Estimation of Native Proteins by Blue Native Electrophoresis  

PubMed Central

Blue native electrophoresis is one of the most popular techniques for mass estimation of native membrane proteins, but the use of non-optimal mass markers and acrylamide gels can compromise accuracy and reliability of the results. We present short protocols taking 10–30 min to prepare optimal sets of membrane protein markers from chicken, rat, mouse, and bovine heart. Especially heart materials from local supermarkets or butcher's shops, e.g. chicken or bovine heart, are ideal sources of high mass membrane protein standards. Considerable discrepancies between the migration behavior of membrane and soluble markers suggest using membrane protein markers for mass estimation of membrane proteins. Soluble standard proteins can be used, with some limitations, when soluble proteins are the focus. Principles and general rules for the determination of mass and oligomeric state of native membrane and soluble proteins are elaborated, and potential pitfalls are discussed. PMID:20173216

Wittig, Ilka; Beckhaus, Tobias; Wumaier, Zibiernisha; Karas, Michael; Schägger, Hermann

2010-01-01

171

Analysis of Estrogen Receptor Dinucleotide Polymorphism by Capillary Gel Electrophoresis with a Population Genetic Study in 180 Finns  

Microsoft Academic Search

We developed a suitable method for analysing dinucleotide repeats found in the upstream of human alpha-estrogen receptor (ER) gene by applying capillary electrophoresis and automatic analysis. This method omits the gel-casting step as well as difficult handling of long polyacrylamide sequencing gels. Use of radioactive materials is also avoided. Using this method, the frequency distribution of ER alleles, determined in

Tarja A. Kunnas; Doris Holmberg-Marttila; Pekka J. Karhunen

1999-01-01

172

Native Intelligence  

ERIC Educational Resources Information Center

Amid concerns from tribal leaders that No Child Left Behind testing is squeezing out electives that have traditionally covered their history and cultures, an ambitious brace of programs is making Native America part of the core curriculum at David Wolfle Elementary School and other schools in the western Washington State. By tapping into…

Seven, Richard

2006-01-01

173

Multimaterial polyacrylamide: fabrication with electrohydrodynamic jet printing, applications, and modeling.  

PubMed

Micropatterned, multimaterial hydrogels have a wide range of applications, including the study of microenvironmental factors on cell behavior, and complex materials that rapidly change shape in response to fluid composition. This paper presents a method to fabricate microscale polyacrylamide features embedded in a second hydrogel of a different composition. An electrohydrodynamic jet (e-jet) printer was used to pattern hemispherical droplets of polyacrylamide prepolymer on a passive substrate. After photopolymerization, the droplets were backfilled with a second polyacrylamide mixture, the second mixture was polymerized and the sample was peeled off the substrate. Fluorescent and confocal microscopy confirmed multimaterial patterning, while scanning probe microscopy revealed a patterned topography with printed spots forming shallow wells. Finite element modeling was used to understand the mechanics of the formation of the topographical features during backfill and subsequent polymerization. Finally, polyacrylamide containing acrylic acid was used to demonstrate two applications of the micropatterned hydrogels: stimuli-responsive materials and patterned substrates for cell culture. The e-jet fabrication technique described here is a highly flexible, high resolution method for creating multimaterial hydrogels. PMID:24991937

Poellmann, Michael J; Johnson, Amy J Wagoner

2014-09-01

174

POLYACRYLAMIDE EFFECTS ON WATER INFILTRATION IN SANDY LOAM SOILS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Some sandy soils of the California San Joaquin Valley have low water infiltration. Electrical conductivity (EC) and sodium adsorption ratio (SAR) of irrigation water greatly affect infiltration rate and hydraulic conductivity of soils. High molecular weight polyacrylamides (PAM) have been shown to i...

175

HRP-Mediated Synthesis of Starch-Polyacrylamide Graft Copolymers  

Technology Transfer Automated Retrieval System (TEKTRAN)

Modified starch-based polymers can be engineered for specific properties by combining starch with synthetic polymers through graft copolymerization. Polyacrylamide grafted starches have received a great deal of applications in areas such as superabsorbent paper-making additives, drag reduction and ...

176

Organic matter and polyacrylamide amendment of Norfolk loamy sand  

Microsoft Academic Search

Loamy sand soils of the southeastern USA Coastal Plains often have poor physical properties because they contain cemented subsurface hard layers that restrict root development and yield. Their physical properties can be improved by adding amendments. Polyacrylamide (PAM) amendments and\\/or organic matter (OM) in the form of ground wheat (Triticum aestivum L.) stubble or pecan (Carya illinoensis) branches were mixed

W. J. Busscher; J. M. Novak; T. C. Caesar-TonThat

2007-01-01

177

Polyacrylamide Effectiveness in Reducing Soil and P Loss from  

E-print Network

(OH-) units #12;PAM for Soil Erosion · Characteristics of most PAMs used for soil erosion applications prevent Erosion From water on the web · Raindrop Impact Effect ­ Soil Crusting · Impact destabilizes soilPolyacrylamide Effectiveness in Reducing Soil and P Loss from Agricultural Fields Adam Peterson1

Balser, Teri C.

178

HRP-Mediated Synthesis of Starch-Polyacrylamide Graft Copolymers  

Technology Transfer Automated Retrieval System (TEKTRAN)

Modified starch-based polymers can be engineered for specific properties by combining starch with synthetic polymers through graft copolymerization. Polyacrylamide grafted starch have received a great deal of applications in areas such as superabsorbent paper-making additives, drag reduction and te...

179

PREPARATION OF STARCH-G-POLYACRYLAMIDE COPOLYMERS BY REACTIVE EXTRUSION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Graft copolymers of starch and polyacrylamide were prepared by reactive extrusion using a co-rotating twin screw extruder and ammonium persulfate initiator. Feed rates were 109 g/min up to 325 g/min (all components) at a moisture content of 50 percent, with screw speeds in the range 100 rpm to 300 ...

180

PREPARATION OF STARCH-GRAFT-POLYACRYLAMIDE COPOLYMERS BY REACTIVE EXTRUSION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Graft copolymers of starch and polyacrylamide (PAAm) were prepared by reactive extrusion using a co-rotating twin screw extruder and ammonium persulfate initiator. Feed rates were 109 g/min to 325 g/min (all components) at a moisture content of 50%, with screw speeds in the range 100 rpm to 300 rpm...

181

Scaling Behaviors and Mechanical Properties of Polymer Gels  

NASA Astrophysics Data System (ADS)

Polymer gels undergo a volume phase transition in solvent in response to an infinitesimal environmental change. This remarkable phenomenon has resulted in many potential applications of polymer gels. The understanding of its mechanical properties has both scientific and technological importance. For this purpose, we have developed a novel method for measuring Poisson's ratio, which is one of the most important parameters determining the mechanical property of gels. Using this method, Poisson's ratio in N-isopropyacryl -amide (NIPA) and polyacrylamide (PAAM) gels has been studied. We obtained that Poisson's ratio goes through a negative dip in both neutral and ionic NIPA gels, but positive in the PAAM gels. It was found that the scaling exponent delta depends on the details of chemical ingredients and polymerization process. In the salt solution, the delta depends on both the network ionization and the solvent salt concentration. The study of acoustic attenuation and velocity of NIPA gels reveals the dynamic scaling behavior of NIPA gels near the transition point. It has been found that there are four different pattern regions on the surface of constrained gel films depending on the temperature (or acetone concentration) and ionic strength of the sample, these patterns are associated with the mechanical instability of gel surface. The work presented in this dissertation will help ones both in the theoretical understanding and practical application of the gel system.

Li, Chunfang

182

Laser CT evaluation on normoxic PAGAT gel dosimeter  

NASA Astrophysics Data System (ADS)

Optical computed tomography has been shown to be a potentially useful imaging tool for the radiation therapy physicists. In radiation therapy, researchers have used optical CT for the readout of 3D dosimeters. The purpose of this paper is to describe the initial evaluation of a newly fabricated laser CT scanner for 3D gel dosimetry which works using the first generation principle. A normoxic PAGAT (Polyacrylamide Gelatin and Tetrakis) gel is used as a dosimeter for this analysis. When a laser passes through the gel phantom, absorption and scattering of photon take place. The optical attenuation coefficient of the laser can be obtained by measuring its intensity after passing through the gel by a sensor. The scanner motion is controlled by a computer program written in Microsoft Visual C++. Reconstruction and data analysis on the irradiated gel phantom is performed by suitable algorithm using Matlab software.

Kumar, D. S.; Samuel, E. J. J.; Watanabe, Y.

2013-06-01

183

Application of multiple levels of fluid shear stress to endothelial cells plated on polyacrylamide gels.  

PubMed

Measurements of endothelial cell response to fluid shear stress have previously been performed on unphysiologically rigid substrates. We describe the design and implementation of a microfluidic device that applies discrete levels of shear stress to cells plated on hydrogel-based substrates of physiologically-relevant stiffness. The setup allows for measurements of cell morphology and inflammatory response to the combined stimuli, and identifies mechanisms by which vascular stiffening leads to pathological responses to blood flow. We found that the magnitude of shear stress required to affect endothelial cell morphology and inflammatory response depended on substrate stiffness. Endothelial cells on 100 Pa substrates demonstrate a greater increase in cell area and cortical stiffness and decrease in NF-?B nuclear translocation in response to TNF-? treatment compared to controls than cells plated on 10 kPa substrates. The response of endothelial cells on soft substrates to shear stress depends on the presence of hyaluronan (HA). These results emphasize the importance of substrate stiffness on endothelial function, and elucidate a means by which vascular stiffening in aging and disease can impact the endothelium. PMID:25573790

Galie, P A; van Oosten, A; Chen, C S; Janmey, P A

2015-02-01

184

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

185

Intra-Articular Polyacrylamide Hydrogel Injections Are Not Innocent  

PubMed Central

Osteoarthritis is a chronic disorder characterized by joint cartilage degeneration with concomitant changes in the synovium and subchondral bone metabolism. Many conservative treatment modalities, one of which is intra-articular injections, have been described for the treatment of this disorder. Traditionally, hyaluranic acid and corticosteroids are the agents that have been used for this purpose. Recently, polyacrylamide hydrogels are being used widely. Biocompatibility, nonbioabsorbability, and anti-infectious effect obtained by silver addition made polyacrylamide hydrogels more popular. In this paper, we present a case and the method of our management, in whom host tissue reaction (foreign body granuloma, edema, inflammation, and redness induration) has been observed, as the first and unique adverse effect reported in the literature. PMID:25197596

Tonbul, Murat; Adas, Mujdat; Bekmezci, Taner; Kara, Ahmet Duran

2014-01-01

186

Microwave enhanced synthesis of chitosan- graft-polyacrylamide  

Microsoft Academic Search

Chitosan-graft-polyacrylamide (Ch-g-PAM) was synthesized without any radical initiator or catalyst using microwave (MW) irradiation. Under optimal grafting conditions, 169% grafting was observed at 80% MW power in 1.16min. Conventionally under similar conditions a maximum grafting of 82% could be achieved in 1h using K2S2O8\\/ascorbic acid as redox initiator coupled with Ag+ ions as catalyst and atmospheric oxygen as co-catalyst on

Vandana Singh; Ashutosh Tiwari; Devendra Narayan Tripathi; Rashmi Sanghi

2006-01-01

187

Reprogramming cellular phenotype by soft collagen gels.  

PubMed

A variety of cell types exhibit phenotype changes in response to the mechanical stiffness of the substrate. Many cells excluding neurons display an increase in the spread area, actin stress fiber formation and larger focal adhesion complexes as substrate stiffness increases in a sparsely populated culture. Cell proliferation is also known to directly correlate with these phenotype changes/changes in substrate stiffness. Augmented spreading and proliferation on stiffer substrates require nuclear transcriptional regulator YAP (Yes associated protein) localization in the cell nucleus and is tightly coupled to larger traction force generation. In this study, we show that different types of fibroblasts can exhibit spread morphology, well defined actin stress fibers, and larger focal adhesions even on very soft collagen gels (modulus in hundreds of Pascals) as if they are on hard glass substrates (modulus in GPa, several orders of magnitude higher). Strikingly, we show, for the first time, that augmented spreading and other hard substrate cytoskeleton architectures on soft collagen gels are not correlated with the cell proliferation pattern and do not require YAP localization in the cell nucleus. Finally, we examine the response of human colon carcinoma (HCT-8) cells on soft collagen gels. Recent studies show that human colon carcinoma (HCT-8) cells form multicellular clusters by 2-3 days when cultured on soft polyacrylamide (PA) gels with a wide range of stiffness (0.5-50 kPa) and coated with an extracellular matrix, ECM (collagen monomer/fibronectin). These clusters show limited spreading/wetting on PA gels, form 3D structures at the edges, and eventually display a remarkable, dissociative metastasis like phenotype (MLP), i.e., epithelial to rounded morphological transition after a week of culture on PA gels only, but not on collagen monomer coated stiff polystyrene/glass where they exhibit enhanced wetting and form confluent monolayers. Here, we show that HCT-8 cell clusters also show augmented spreading/wetting on soft collagen gels and eventually form confluent monolayers as on rigid glass substrates and MLP is completely inhibited on soft collagen gels. Overall, these results suggest that cell-material interactions (soft collagen gels in this case) can induce cellular phenotype and cytoskeleton organization in a remarkably distinct manner compared to a classical synthetic polyacrylamide (PA) hydrogel cell culture model and may contribute in designing new functional biomaterials. PMID:25284029

Ali, M Yakut; Chuang, Chih-Yuan; Saif, M Taher A

2014-11-28

188

The latest advancements in proteomic two-dimensional gel electrophoresis analysis applied to biological samples.  

PubMed

Two-dimensional gel electrophoresis (2DE) is one of the fundamental approaches in proteomics for the separation and visualization of complex protein mixtures. Proteins can be analyzed by 2DE using isoelectric focusing (IEF) in the first dimension, combined to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the second dimension, gel staining (silver and Coomassie), image analysis, and 2DE gel database. High-resolution 2DE can resolve up to 5,000 different proteins simultaneously (?2,000 proteins routinely), and detect and quantify <1 ng of protein per spot. Here, we describe the latest developments for a more complete analysis of biological fluids. PMID:25384742

Santucci, Laura; Bruschi, Maurizio; Ghiggeri, Gian Marco; Candiano, Giovanni

2015-01-01

189

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

190

Puncturing of soft gels with multi-tip needles  

Microsoft Academic Search

Resistance to insertion of a sharp object into a soft solid is known to depend upon the macroscopic geometry of the tool and\\u000a the consequent fracture mechanisms involved. In this article, we have examined it by carrying out displacement controlled\\u000a puncturing into soft, brittle polyacrylamide gels using hypodermic needles of different diameters. These experiments show\\u000a that in contrast to a

Susmita Das; Animangsu Ghatak

2011-01-01

191

Injectable gels of anionic collagen:rhamsan composites for plastic correction: preparation, characterization, and rheological properties.  

PubMed

The present article describes the preparation and characterization of anionic collagen gels obtained from porcine intestinal submucosa after 72 h of alkaline treatment and in the form of rhamsan composites to develop injectable biomaterials for plastic reconstruction. All materials were characterized by SDS/polyacrylamide gel electrophoresis, infrared spectroscopy, thermal stability, potentiometric titration, rheological properties, and fluidity tests. Biocompatibility was appraised after the injection of anionic collagen: rhamsan composites at 2.5% in 60 North Folk rabbits. Independently of processing, the collagen's secondary structure was preserved in all cases, and after 72 h of hydrolysis the collagen was characterized by a carboxyl group content of 346+/-9, which, at physiological pH, corresponds to an increase of 106+/-17 negative charges, in comparison to native collagen, due to the selective hydrolysis of asparagine and glutamine carboxyamide side chain. Rheological studies of composites at pH 7.4 in concentrations of 2, 4, and 6% (in proportions of 75:1 and 50:1) showed a viscoelastic behavior dependent on the frequency, which is independent of concentration and proportion. In both, the concentration of the storage modulus always predominated over the loss modulus (G'>G'' and delta<45 degrees ). The results from creep experiments confirmed this behavior and showed that anionic collagen:rhamsan composites at pH 7.4 in the proportion of 50:1 are less elastic and more susceptible to deformation in comparison to gels in the proportion of 75:1, independent of concentration. This was further confirmed by flow experiments, indicating that the necessary force for the extrusion of anionic collagen:rhamsan composites, in comparison to anionic collagen, was significantly smaller and with a smooth flow. Biocompatibility studies showed that the tissue reaction of anionic collagen:rhamsan composites at 2.5% in the proportion of 75:1 was compatible with the application of these gels in plastic reconstruction. These results suggest that the association of collagen with rhamsan may be a good alternative in the replacement of glutaraldehyde to stabilize the microfibril assembly of commercial collagen gel preparations. PMID:16037966

de Paula, Márcio; Goissis, Gilberto; Martins, Virgínia C A; da Silva Trindade, José Carlos

2005-11-01

192

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

193

Turning a PAGE: the overnight sensation of SDS-polycrylamide gel electrophoresis  

Microsoft Academic Search

The zonal separation of proteins on the basis of net charge was initially conducted on paper, then in columns of sucrose and later in gels of starch and polyacrylamide, with appropriate electric fields. Then, in 1964, a graduate student at MIT discovered the power of sodium dodecyl sulfate (SDS) to dissoci- ate the envelope proteins of Escherichia coli and to

Thoru Pederson

2007-01-01

194

Comparative gel electrophoresis analysis of helical junctions in RNA.  

PubMed

Comparative gel electrophoresis provides information on the relative angles subtended between helical arms at a branchpoint in RNA. It is based upon the comparison of electrophoretic mobility in polyacrylamide gels of species containing two long arms, with the remaining one(s) being significantly shorter. Although the method currently lacks a really well-established basis of physical theory, it is very powerful, yet simple to apply. It has had a number of significant successes in RNA, DNA and DNA-protein complexes, and in all cases to date the results have stood the test of time and eventual comparison with crystallographic analysis. PMID:20946788

Lilley, David M J

2009-01-01

195

Measurements of Elastic Moduli of Silicone Gel Substrates with a Microfluidic Device  

PubMed Central

Thin layers of gels with mechanical properties mimicking animal tissues are widely used to study the rigidity sensing of adherent animal cells and to measure forces applied by cells to their substrate with traction force microscopy. The gels are usually based on polyacrylamide and their elastic modulus is measured with an atomic force microscope (AFM). Here we present a simple microfluidic device that generates high shear stresses in a laminar flow above a gel-coated substrate and apply the device to gels with elastic moduli in a range from 0.4 to 300 kPa that are all prepared by mixing two components of a transparent commercial silicone Sylgard 184. The elastic modulus is measured by tracking beads on the gel surface under a wide-field fluorescence microscope without any other specialized equipment. The measurements have small and simple to estimate errors and their results are confirmed by conventional tensile tests. A master curve is obtained relating the mixing ratios of the two components of Sylgard 184 with the resulting elastic moduli of the gels. The rigidity of the silicone gels is less susceptible to effects from drying, swelling, and aging than polyacrylamide gels and can be easily coated with fluorescent tracer particles and with molecules promoting cellular adhesion. This work can lead to broader use of silicone gels in the cell biology laboratory and to improved repeatability and accuracy of cell traction force microscopy and rigidity sensing experiments. PMID:21980487

Gutierrez, Edgar; Groisman, Alex

2011-01-01

196

Synthesis and Study of Anisotropically Interpenetrated Polymer Gels  

NASA Astrophysics Data System (ADS)

A new gel system with built-in anisotropy consists of interpenetrated polymer network (IPN) gels of polyacrylamide (PAAM) and N-isopropylacrylamide (NIPA). This gel is synthesized by pre-stressing one (NIPA) of the network components before gelation of the second network (PAAM) takes place. Physical properties along the pre-stressed direction are expected to be different from those at other directions, in contrast to conventional gels that are isotropic materials. It is found that the ratio (L/D) of length (L) and diameter (D) of IPN samples has step-wise changes as the samples are heated from below the volume phase transition temperature to above. A theoretical model is proposed and is in agreement with the experimental results.

Chen, Yuanye; Wang, Changjie; Hu, Zhibing; Li, Yong

1997-10-01

197

Determination of polyacrylamides in coal washery effluents by ultrafiltration/site-exclusion chromatography-ultraviolet detection techniques  

SciTech Connect

The use of a combined technique of ultrafiltration and aqueous size-exclusion high-performance liquid chromatography-UV detection for monitoring trace levels of residual polyacrylamide flocculants in coal washery process water is described. Flocculants of both anionic and non-ionic types in effluents are analyzed by chromatography on a TSK 5000 PW type hydrophilic and semirigid porous polymer gel with 0.05 M Na/sub 2/SO/sub 4/ in water as the mobile phase and by UV detection at 208-nm wavelength for detection. Precision studies gave a relative standard deviation of 5.8% and a precision of 2.2% at the 95% confidence level in the concentration range of 20 ppm. The lower limit of detection for the method is 1.0 ..mu..g. Prior to chromatography, fractionation and concentration of the polyacrylamide in effluents are achieved by ultrafiltration with a hollow fiber cartridge having a nominal molecular weight cutoff of 100,000, and recoveries are determined by spiking studies. The application of the techniques for the analysis of residual flocculant in a coal washery thickener feed effluent sample is described.

Leung, R.W.M.; Pandey, R.N.; Das, B.S.

1987-05-01

198

Effects of polymer concentration on the morphology of calcium phosphate crystals formed in polyacrylamide hydrogels  

NASA Astrophysics Data System (ADS)

Growing crystals in hydrogels is an attractive method to form inorganic solids with designed morphology under ambient conditions. Precipitation of the inorganic solids in a hydrogel matrix can be regarded as mimicking the process of biomineralization. In the construction of biominerals, an organic template composed of insoluble macromolecules is used to control the crystal growth of the inorganic compounds. The morphological control in biomineralization can be applied to artificial reaction systems. In this study, the morphology of calcium phosphate crystals formed in polymeric hydrogels of various polymer concentrations was investigated. Spherical octacalcium phosphate (OCP) precipitated in the polyacrylamide (PAAm) hydrogels. Fibrous crystals gradually covered the surface of the spherical crystals as the polymer concentration of the gel increased. The morphology of the OCP crystals changed from sea urchin shapes to wool-ball shapes with increasing PAAm concentration. The morphological change is generated by the template effect of the polymer wall, which is made up of stacked PAAm sheets, surrounding the spherical OCP crystals.

Yokoi, Taishi; Kawashita, Masakazu; Ohtsuki, Chikara

2013-11-01

199

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. PMID:22702416

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

2012-01-01

200

Recycling of superfine resolution agarose gel.  

PubMed

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

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

2013-01-01

201

Native American Healing Traditions  

Microsoft Academic Search

Indigenous healing practices among Native Americans have been documented in the United States since colonisation. Cultural encapsulation has deterred the acknowledgement of Native American medicinal practices as a precursor to folk medicine and many herbal remedies, which have greatly influenced modern medicine. Understanding Native American healing practices requires helping professionals to have knowledge of Native American cultural belief systems about

Tarrell A. A. Portman; Michael T. Garrett

2006-01-01

202

Gel pad array chip for high throughput and multi-analyte microbead-based immunoassays.  

PubMed

We present here a gel pad array chip for high-throughput and multi-analyte microbead-based immunoassays. The chip is fabricated by photo-patterning of two polymeric gels, polyacrylamide gel and polyethylene glycol (PEG) gel, on a glass slide. The resulting chip consists of 40 polyacrylamide gel pad array units for the immobilization of microbeads and each gel pad array is surrounded with a PEG micropillar ring to confine the samples within the microarray. As a proof of concept, this chip was tested for quantitative immunoassays for two model cancer markers, human chorionic gonadotropin (hCG) and prostate specific antigen (PSA), in serum samples. Detection limits below the physiological threshold level for cancer diagnosis were achieved with good inter- and intra-chip reproducibility. Moreover, by using spatial encoded microbeads, simultaneous detection of both hCG and PSA on each gel pad array is achieved with single filter fluorescence imaging. This gel pad array chip is easy to use, easy to fabricate with low cost materials and minimal equipment and reusable. It could be a useful tool for common biolabs to customize their own microbead array for multi-analyte immunoassays. PMID:25463645

Zhu, Qingdi; Trau, Dieter

2015-04-15

203

Engineering cartilage in a photochemically crosslinked collagen gel.  

PubMed

This study's purpose was to investigate whether photochemically crosslinking collagen gel to encapsulate chondrocytes (articular, auricular, costal) would permit new cartilage formation in vivo, and to determine whether this neocartilage had the ability to integrate with existing native cartilage. Chondrocytes from swine were embedded in collagen gel that was photochemically crosslinked using riboflavin and visible light. Controls were collagen gels containing cells that were not crosslinked. Cylindrical implants (0.1 cc) were placed in athymic mice for 4 and 8 weeks. To study integration, the constructs were crosslinked within articular cartilage rings and implanted in the mice. Samples were analyzed in terms of macroscopic, microscopic, and biochemical aspects. Photocrosslinking did not affect the amount of glycosaminoglycan and type II collagen produced by the cells. We found that photochemical crosslinking collagen gel enhances the physical parameters of the gel and permits new cartilage formation that can integrate with existing native cartilage. PMID:19216355

Ibusuki, Shinichi; Papadopoulos, Anestis; Ranka, Milan P; Halbesma, Gertjan J; Randolph, Mark A; Redmond, Robert W; Kochevar, Irene E; Gill, Thomas J

2009-01-01

204

Porous Polyacrylamide Monoliths in Hydrophilic Interaction Capillary Electrochromatography of Oligosaccharides  

PubMed Central

Capillary electrochromatography (CEC) of oligosaccharides in porous polyacrylamide monoliths has been explored. While it is possible to alter separation capacity for various compounds by copolymerization of suitable separation ligands in the polymerization backbone, “blank” acrylamide matrix is also capable of sufficient resolution of oligosaccharides in the hydrophilic interaction mode. The “blank” acrylamide network, formed with a more rigid crosslinker, provides maximum efficiency for separations (routinely up to 350,000 theoretical plates/m for fluorescently-labeled oligosaccharides). These columns yield a high spatial resolution of the branched glycan isomers and large column permeabilities. From the structural point of view, some voids are observable in the monoliths at the mesoporous range (mean pore radius ca. 35 nm, surface area of 74 m2/g), as measured by intrusion porosimetry in the dry state. PMID:17254635

Gury?a, Vilém; Mechref, Yehia; Palm, Anders K.; Michálek, Ji?í; Pacáková, V?ra; Novotný, Miloš V.

2007-01-01

205

Production and characterization of immobilized-biomass carriers, using polyacrylamide.  

PubMed

Whole microbial cells from an activated sludge seed were immobilised in spherical polyacrylamide beads using a shrink/swell procedure which increased cell viability more than 100-fold over the seed material. The process was optimised with respect to the seed concentration and incubation time. It was shown that the swell procedure was essential to achieve good immobilisation and that biofilm attachment to the beads made a negligible contribution to the immobilised biomass. The physical and biological properties of the immobilised beads were determined and found to settle well and resist mechanical abrasion. In addition, their preparation did not prove toxic to the immobilised biomass. The beads produced have many applications for instance in enhancing the biomass in wastewater treatment processes. In addition the immobilisation process could be applied to a wide range of microbial consortia including pure cultures of microorganisms. PMID:15369286

Horan, N J; Huo, C X

2004-06-01

206

Flows of polymer solutions through contractions Part 1: flows of polyacrylamide solutions through planar contractions  

Microsoft Academic Search

The present paper is devoted to the mechanism of vortex enhancement and the occurrence of lip vortices in contraction flows of viscoelastic fluids. The FENE-P model was used in order to simulate earlier experimental results of Evans and Walters for the flow of aqueous polyacrylamide solutions through planar contractions. The influence of the contraction ratio, the polyacrylamide concentration and the

B. Purnode; M. J. Crochet

1996-01-01

207

Controlling residual dipolar couplings in high-resolution NMR of proteins by strain induced alignment in a gel  

Microsoft Academic Search

Water-soluble biological macromolecules can be weakly aligned by dissolution in a strained, hydrated gel such as cross-linked polyacrylamide, an effect termed `strain-induced alignment in a gel' (SAG). SAG induces nonzero nuclear magnetic dipole-dipole couplings that can be measured in high-resolution NMR spectra and used as structural constraints. The dependence of experimental 15N-1H dipolar couplings extracted from two-dimensional heteronuclear single quantum

Yoshitaka Ishii; Michelle A. Markus; Robert Tycko

2001-01-01

208

Purification of native myosin filaments from muscle.  

PubMed Central

Analysis of the structure and function of native thick (myosin-containing) filaments of muscle has been hampered in the past by the difficulty of obtaining a pure preparation. We have developed a simple method for purifying native myosin filaments from muscle filament suspensions. The method involves severing thin (actin-containing) filaments into short segments using a Ca(2+)-insensitive fragment of gelsolin, followed by differential centrifugation to purify the thick filaments. By gel electrophoresis, the purified thick filaments show myosin heavy and light chains together with nonmyosin thick filament components. Contamination with actin is below 3.5%. Electron microscopy demonstrates intact thick filaments, with helical cross-bridge order preserved, and essentially complete removal of thin filaments. The method has been developed for striated muscles but can also be used in a modified form to remove contaminating thin filaments from native smooth muscle myofibrils. Such preparations should be useful for thick filament structural and biochemical studies. PMID:11606293

Hidalgo, C; Padrón, R; Horowitz, R; Zhao, F Q; Craig, R

2001-01-01

209

Restoring Native Grasslands  

E-print Network

Much of Texas' native grasslands has been converted to improved pastures and cropland, neither of which is suitable for wildlife habitat. Now, many landowners are interested in restoring native grasses because they are cheaper to produce for forage...

Hays, K. Brian; Wagner, Matthew; Smeins, Fred; Wilkins, Neal

2005-03-23

210

Experiencing Native American Culture.  

ERIC Educational Resources Information Center

Presents four experiential excercises based on Native American culture for use in education, communication training, and counseling. These excercises are intended as vehicles for personal growth and aids to learning about Native American culture. (RC)

Darou, Wes G.

1980-01-01

211

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

212

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

213

Native American Healing Traditions  

ERIC Educational Resources Information Center

Indigenous healing practices among Native Americans have been documented in the United States since colonisation. Cultural encapsulation has deterred the acknowledgement of Native American medicinal practices as a precursor to folk medicine and many herbal remedies, which have greatly influenced modern medicine. Understanding Native American…

Portman, Tarrell A. A.; Garrett, Michael T.

2006-01-01

214

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

PubMed Central

Background In a traditional electrophoresis mobility shift assay (EMSA) a 32P-labeled double-stranded DNA oligonucleotide or a restriction fragment bound to a protein is separated from the unbound DNA by polyacrylamide gel electrophoresis (PAGE) in nondenaturing conditions. An extension of this method uses the large population of fragments derived from long genomic regions (approximately 600 kb) for the identification of fragments containing protein binding regions. With this method, genomic DNA is fragmented by restriction enzymes, fragments are amplified by PCR, radiolabeled, incubated with nuclear proteins and the resulting DNA-protein complexes are separated by two-dimensional PAGE. Shifted DNA fragments containing protein binding sites are identified by using additional procedures, i. e. gel elution, PCR amplification, cloning and sequencing. Although the method allows simultaneous analysis of a large population of fragments, it is relatively laborious and can be used to detect only high affinity protein binding sites. Here we propose an alternative and straightforward strategy which is based on a combination of native and denaturing PAGE. This strategy allows the identification of DNA fragments containing low as well as high affinity protein binding regions, derived from genomic DNA (<10 kb) of known sequence. Results We have combined an EMSA-based selection step with subsequent denaturing PAGE for the localization of protein binding regions in long (up to10 kb) fragments of genomic DNA. Our strategy consists of the following steps: digestion of genomic DNA with a 4-cutter restriction enzyme (AluI, BsuRI, TruI, etc), separation of low and high molecular weight fractions of resultant DNA fragments, 32P-labeling with Klenow polymerase, traditional EMSA, gel elution and identification of the shifted bands (or smear) by denaturing PAGE. The identification of DNA fragments containing protein binding sites is carried out by running the gel-eluted fragments alongside with the full "spectrum" of initial restriction fragments of known size. Here the strategy is used for the identification of protein-binding regions in the 5' region of the rat p75 neurotrophin receptor (p75NTR) gene. Conclusion The developed strategy is based on a combination of traditional EMSA and denaturing PAGE for the identification of protein binding regions in long fragments of genomic DNA. The identification is straightforward and can be applied to shifted bands corresponding to stable DNA-protein complexes as well as unstable complexes, which undergo dissociation during electrophoresis. PMID:18533036

Kaer, Kristel; Mätlik, Kert; Metsis, Madis; Speek, Mart

2008-01-01

215

Beta beta homodimers exist in native rabbit skeletal muscle tropomyosin and increase after denaturation-renaturation.  

PubMed

Native tropomyosin from rabbit skeletal muscle (RSTm) consists mainly of alpha alpha and alpha beta coiled coils (alpha/beta approximately 3-4/1). In some extant studies, no beta beta molecules have been found. In this study, RSTm from several different preparations was disulfide cross-linked, both preparation and cross-linking being done under nondenaturing conditions. The cross-linked product was assayed for the presence of beta beta molecules cross-linked at both C36 and C190 (beta = beta). In such cross-linked RSTm, 3-8% beta = beta is detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis, C4 reversed-phase high-performance liquid chromatography, and a free-solution capillary electrophoresis experiment. This percentage becomes approximately 4-10% beta beta when corrected for incomplete double cross-linking and is independent of protein concentration (0.1-10.0 mg/mL), indicating that the observed beta beta species are not artifacts due to intermolecular cross-linking. Upon denaturation and subsequent renaturation either by heating to 55 degrees C or by incubating at 45 degrees C followed by quenching to room temperature, or by guanidine hydrochloride exposure followed by phased renaturation by dialysis, the fraction of beta beta increases, indicating that the reassociation favors homodimer formation somewhat over random association. This result differs from the random association observed when the sulfhydryl on one of the chains is carboxyamidomethylated (Holtzer, M.E., Breiner, T., & Holtzer, A., 1984, Biopolymers 23, 1811-1833), and from the overwhelming heterodimer preferences reported for tropomyosins from other organisms (Lehrer, S.S., Qian, Y., & Hvidt, S., 1989, Science 246, 926-928; Lehrer, S.S. & Qian, Y., 1990, J. Biol. Chem. 265, 1134-1138). PMID:1304342

Holtzer, M E; Kidd, S G; Crimmins, D L; Holtzer, A

1992-03-01

216

Beta beta homodimers exist in native rabbit skeletal muscle tropomyosin and increase after denaturation-renaturation.  

PubMed Central

Native tropomyosin from rabbit skeletal muscle (RSTm) consists mainly of alpha alpha and alpha beta coiled coils (alpha/beta approximately 3-4/1). In some extant studies, no beta beta molecules have been found. In this study, RSTm from several different preparations was disulfide cross-linked, both preparation and cross-linking being done under nondenaturing conditions. The cross-linked product was assayed for the presence of beta beta molecules cross-linked at both C36 and C190 (beta = beta). In such cross-linked RSTm, 3-8% beta = beta is detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis, C4 reversed-phase high-performance liquid chromatography, and a free-solution capillary electrophoresis experiment. This percentage becomes approximately 4-10% beta beta when corrected for incomplete double cross-linking and is independent of protein concentration (0.1-10.0 mg/mL), indicating that the observed beta beta species are not artifacts due to intermolecular cross-linking. Upon denaturation and subsequent renaturation either by heating to 55 degrees C or by incubating at 45 degrees C followed by quenching to room temperature, or by guanidine hydrochloride exposure followed by phased renaturation by dialysis, the fraction of beta beta increases, indicating that the reassociation favors homodimer formation somewhat over random association. This result differs from the random association observed when the sulfhydryl on one of the chains is carboxyamidomethylated (Holtzer, M.E., Breiner, T., & Holtzer, A., 1984, Biopolymers 23, 1811-1833), and from the overwhelming heterodimer preferences reported for tropomyosins from other organisms (Lehrer, S.S., Qian, Y., & Hvidt, S., 1989, Science 246, 926-928; Lehrer, S.S. & Qian, Y., 1990, J. Biol. Chem. 265, 1134-1138). PMID:1304342

Holtzer, M. E.; Kidd, S. G.; Crimmins, D. L.; Holtzer, A.

1992-01-01

217

Temperature responsive gel displays  

NASA Astrophysics Data System (ADS)

Synthesis and application of engineered surface patterns on environmentally responsive polymer gels are reported here. N-isopropylacrylamide (NIPA) gel was deposited on the masked-surface of an acrylamide gel using photo-initiated polymerization method. The pattern of the NIPA deposited area can be either visible or invisible by simply switching temperature above or below the low critical solution temperature (LCST) of the NIPA gel. Such gels can be used as displays.

Zheng, Yindong; Wang, Changjie; Hu, Zhibing; Li, Yong

1999-10-01

218

Acrylamide monomer leaching from polyacrylamide-treated irrigation furrows.  

PubMed

Water-soluble anionic polyacrylamide (WSPAM), which is used to reduce erosion in furrow irrigated fields and other agriculture applications, contains less than 0.05% acrylamide monomer (AMD). Acrylamide monomer, a potent neurotoxicant and suspected carcinogen, is readily dissolved and transported in flowing water. The study quantified AMD leaching losses from a WSPAM-treated corn (Zea mays L.) field using continuous extraction-walled percolation samplers buried at 1.2 m depth. The samplers were placed 30 and 150 m from the inflow source along a 180-m-long corn field. The field was furrow irrigated using WSPAM at the rate of 10 mg L(-1) during furrow advance. Percolation water and furrow inflows were monitored for AMD during and after three furrow irrigations. The samples were analyzed for AMD using a gas chromatograph equipped with an electron-capture detector. Furrow inflows contained an average AMD concentration of 5.5 microg L(-1). The AMD in percolation water samples never exceeded the minimum detection limit and the de facto potable water standard of 0.5 microg L(-1). The risk that ground water beneath these WSPAM-treated furrow irrigated soils will be contaminated with AMD appears minimal. PMID:18948483

Lentz, R D; Andrawes, F F; Barvenik, F W; Koehn, A C

2008-01-01

219

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

220

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

Code of Federal Regulations, 2012 CFR

...polymer (modified cationic) denture adhesive. 872.3480 Section 872.3480...polymer (modified cationic) denture adhesive. (a) Identification. A polyacrylamide polymer (modified cationic) denture adhesive is a device composed of...

2012-04-01

221

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

Code of Federal Regulations, 2014 CFR

...polymer (modified cationic) denture adhesive. 872.3480 Section 872.3480...polymer (modified cationic) denture adhesive. (a) Identification. A polyacrylamide polymer (modified cationic) denture adhesive is a device composed of...

2014-04-01

222

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

Code of Federal Regulations, 2013 CFR

...polymer (modified cationic) denture adhesive. 872.3480 Section 872.3480...polymer (modified cationic) denture adhesive. (a) Identification. A polyacrylamide polymer (modified cationic) denture adhesive is a device composed of...

2013-04-01

223

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

224

REACTIVE EXTRUSION OF STARCH-POLYACRYLAMIDE GRAFT COPOLYMERS USING VARIOUS STARCHES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Graft copolymers of polyacrylamide and various substrates were prepared by reactive extrusion in a twin screw extruder using ammonium persulfate as initiator. Substrates included unmodified starches (corn, waxy maize, wheat, and potato), cationic starches, dextrin, dextran, and polyvinyl alcohol (P...

225

Genetic variation in Bromus tectorum (Poaceae): comparison between native and introduced populations  

Microsoft Academic Search

The amount and distribution of genetic variation in 51 native (Eurasian and northern African) populations of Bromus tectorum were assessed at 25 loci using starch gel electrophoresis and were compared with our previous results for introduced (North American) populations of this predominantly cleistogamous grass. More alleles and variable loci were detected across populations in the native range than in North

Stephen J Novak; Richard N Mack

1993-01-01

226

Evaluation of Erosion Control Products With and Without Added Polyacrylamide  

NASA Astrophysics Data System (ADS)

Polyacrylamide (PAM) has been demonstrated to greatly reduce erosion in furrow irrigation, but much less is known about its effectiveness on the much steeper slopes typical of construction sites. The purpose of this study was to determine if anionic PAM would enhance erosion control either alone on bare soil or in combination with four types of ground covers commonly used for grass establishment: straw, straw erosion control blanket (ECB), wood fiber, and mechanically bonded fiber matrix (MBFM). Tests were conducted under natural rainfall and vegetation on a 4 percent slope (bare soil, straw, ECB, and MBFM) or using a rainfall simulator (bare soil, straw, wood fiber, MBFM) on either 10 percent or 20 percent slope on three different soil substrates. All ground cover treatments were evaluated with and without PAM applied in solution at 19 kg/ha. The straw, ECB, and MBFM significantly reduced runoff volume, average turbidity, and total sediment lost over five rainfall events on the vegetated plots. The addition of PAM to ground covers only occasionally had significant effects on runoff parameters but did significantly increase vegetative coverage overall. The rainfall simulator tests produced similar results after four events, with the straw, wood fiber, and MBFM all having significantly lower turbidity than the bare soil. The PAM significantly reduced turbidity for both the first and second events but did not consistently improve runoff quality after multiple rainfall events for any ground cover-soil combinations tested. Separate tests of PAM applied before or after straw did not indicate a clear advantage of either approach, but runoff turbidity was often significantly reduced with PAM, especially at the 20 percent slope. Turbidity reductions were attributed to flocculation of eroded sediment.

McLaughlin, Richard A.; Brown, Tabitha T.

2006-06-01

227

Microfluidic device having an immobilized pH gradient and page gels for protein separation and analysis  

DOEpatents

Disclosed is a novel microfluidic device enabling on-chip implementation of a two-dimensional separation methodology. Previously disclosed microscale immobilized pH gradients (IPG) are combined with perpendicular polyacrylamide gel electrophoresis (PAGE) microchannels to achieve orthogonal separations of biological samples. Device modifications enable inclusion of sodium dodecyl sulfate (SDS) in the second dimension. The device can be fabricated to use either continuous IPG gels, or the microscale isoelectric fractionation membranes we have also previously disclosed, for the first dimension. The invention represents the first all-gel two-dimensional separation microdevice, with significantly higher resolution power over existing devices.

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

2014-05-20

228

Multi-scale rheological perspective to polymer solutions and gels in EOR  

Microsoft Academic Search

Polymer flooding for enhanced oil recovery (EOR), especially using polyacrylamide (PAM) based systems, gradually became the\\u000a largest non-Newtonian fluid process of economic significance. Yet, the mechanistic understanding lags behind. In this paper,\\u000a the relations of structures — rheological properties — EOR applications were reviewed and some recent laboratory studies on\\u000a associated PAM and PAM soft gels were introduced. The multi

Xu-long Cao; Zheng-quan Li; Qun-ling Zhang; Gang Wang; Yuan-ze Xu

2007-01-01

229

Two-dimensional gel electrophoresis mapping of proteins isolated from the hyperthermophile Pyrococcus furiosus  

Microsoft Academic Search

Two-dimensional gel electrophoresis (2DE) in polyacrylamide was used to map the proteins in lysates of the archaeon (formerly archaebacterium) Pyrococcus furiosus and to analyze enzymes purified from P. furiosus. The location of the enzymes in the 2DE maps was determined by comigration of lysate proteins with purified enzymes. A 2DE map of P. furiosus proteins with some identifications was produced,

Carol S. Giometti; Sandra L. Tollaksen; Swarnalatha Mukund; Zhi Hao Zhou; Keren Ma; Xuhong Mai; Michael W. W. Adams

1995-01-01

230

Building Native Nations through Native Student's Commitment to Their Communities  

ERIC Educational Resources Information Center

One aspect of building Native nations entails motivating American Indian/Alaska Native youth to become committed to their communities so as to sustain and move forward with the goals of American Indian/Alaska Native nations. This study determined the impact of one Native American Studies department on its Native students' life goals. Through its…

Lee, Tiffany S.

2009-01-01

231

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

232

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

233

Native Hawaiian Scholarship Aha  

E-print Network

Native Hawaiian Scholarship Aha 2012-2013 #12;Sponsored by ·Native Hawaiian Education Association i #12;Program ·College Fair ·College and Scholarship Overview ·Scholarship Program Presentations #12;Applying for Financial aid is Hard But... " There are lots of people who want to help. üScholarship

234

Native Hawaiian Scholarship `Aha !  

E-print Network

Native Hawaiian Scholarship `Aha ! 2011­2012" #12;Sponsored by" ·Native Hawaiian Education of Hawai`i" #12;Program" ·College Fair" ·College and Scholarship Overview" ·Scholarship Program of people who want to help !Scholarship program staff !Financial aid office !High school and college

235

Native American Entrepreneurship. Digest.  

ERIC Educational Resources Information Center

Although Native Americans have owned and started the fewest small businesses of all U.S. minority groups, entrepreneurship is considered to be an efficient tool for alleviating their economic problems. Barriers to Native American entrepreneurship include poverty, scarce start-up capital, poor access to business education and technical assistance,…

Seymour, Nicole

236

Listen to the Natives  

ERIC Educational Resources Information Center

"Digital natives" refer to today's students because they are native speakers of technology, fluent in the digital language of computers, video games, and the Internet. Those who were not born into the digital world are referred to as digital immigrants. Educators, considered digital immigrants, have slid into the 21st century--and into the digital…

Prensky, Marc

2006-01-01

237

Native American Interdisciplinary Unit.  

ERIC Educational Resources Information Center

This paper presents a cross-graded, thematic, interdisciplinary unit which grew from a Native American humanities unit. The 9-week unit addresses the plurality of intelligences, allows for cognitive bypassing and challenges students in critical thinking modalities. With a focus on the five groups of Native Americans (The Eastern Woodlands, Plains,…

Sorensen, Carol; Hoffmann, Donald; Boinczan, Joseph

238

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

239

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

240

Federal Politics and Native Concerns. Native Viewpoints.  

ERIC Educational Resources Information Center

Addresses some of the frustration felt by Canada's indigenous Indian population regarding the lack of attention afforded them in recent federal elections. Discusses Indian reaction to the Canadian Government's White Paper on Aboriginal peoples. Canadian natives felt this document actually represented a step backward in their struggle for equality.…

Steinhauer, Noella

1997-01-01

241

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

242

Non?native Ants Are Smaller than Related Native Ants  

Microsoft Academic Search

I compare the sizes of non-native and native ants to evaluate how worker size may be related to the ability of a species to invade new habitats. I compare the size of 78 non-native ant species belonging to 26 genera with the size of native congeneric species; native ants are larger than non-native ants in 22 of 26 genera. Ants

Terrence P. McGlynn

1999-01-01

243

ISOLATION OF EGG DROP SYNDROME VIRUS AND ITS MOLECULAR CHARACTERIZATION USING SODIUM DODECYL SULPHATE POLYACRYLAMIDE GEL ELECTROPHORESIS  

Microsoft Academic Search

Six isolates of egg drop syndrome (EDS) virus were recovered from five different outbreaks of EDS in commercial laying hens in and around Faisalabad. The aberrant eggs were fed to the susceptible laying hens for experimental induction of infection. The samples from infected birds (egg washing, cloacal swabs, oviducts and spleens) were collected, processed and inoculated into 11-day old duck

M. H. Rasool; S. U. Rahman; M. K. Mansoor

2005-01-01

244

Sol-Gel Glasses  

NASA Technical Reports Server (NTRS)

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

Mukherjee, S. P.

1985-01-01

245

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.

246

California Native Plant Society  

NSDL National Science Digital Library

This website presents the California Native Plant Society, a national leader in biological diversity conservation science and advocacy. Established in 1965, the CNPS "is a statewide non-profit organization of amateurs and professionals with a common interest in California's native plants." The site provides a variety of information and resources useful to botanists and native plant enthusiasts alike. One notable feature is the site's Photo Gallery which contains many beautiful annotated photos from different parts of California. The site links to the Inventory of Rare and Endangered Plants presenting "the most recent Inventory data from CNPS, plus thumbnail illustrations, maps, a variety of search tools, and links to additional information." The site also links to information about the Native Plant Conservation Campaign, the Manual of California Vegetation (reported on in the Scout Report for Science & Engineering on December 9, 1998), and to online discussion opportunities.

247

Native Health Research Database  

MedlinePLUS

... THIS APP WITH JAVASCRIPT TURNED OFF. THE NATIVE HEALTH DATABASE REQUIRES JAVASCRIPT IN ORDER TO FUNCTION. PLEASE ... Data and Links, U.S. Census Bureau American Indian Health from the National Library of Medicine Arctic Health ...

248

Native American Identity  

ERIC Educational Resources Information Center

Many issues and elements--including ethnic nomenclature, racial attitudes, and the legal and political status of American Indian nations and Indian people--influence Native American identity. (Contains 3 notes.)

Horse, Perry G.

2005-01-01

249

CONFORMANCE IMPROVEMENT USING GELS  

SciTech Connect

This report describes work performed during the second year of the project, ''Conformance Improvement Using Gels.'' The project has two objectives. The first objective is to identify gel compositions and conditions that substantially reduce flow through fractures that allow direct channeling between wells, while leaving secondary fractures open so that high fluid injection and production rates can be maintained. The second objective is to optimize treatments in fractured production wells, where the gel must reduce permeability to water much more than that to oil. Pore-level images from X-ray computed microtomography were re-examined for Berea sandstone and porous polyethylene. This analysis suggests that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than a gel-ripping mechanism. This finding helps to explain why aqueous gels can reduce permeability to water more than to oil. We analyzed a Cr(III)-acetate-HPAM gel treatment in a production well in the Arbuckle formation. The availability of accurate pressure data before, during, and after the treatment was critical for the analysis. After the gel treatment, water productivity was fairly constant at about 20% of the pre-treatment value. However, oil productivity was stimulated by a factor of 18 immediately after the treatment. During the six months after the treatment, oil productivity gradually decreased to approach the pre-treatment value. To explain this behavior, we proposed that the fracture area open to oil flow was increased substantially by the gel treatment, followed by a gradual closing of the fractures during subsequent production. For a conventional Cr(III)-acetate-HPAM gel, the delay between gelant preparation and injection into a fracture impacts the placement, leakoff, and permeability reduction behavior. Formulations placed as partially formed gels showed relatively low pressure gradients during placement, and yet substantially reduced the flow capacity of fractures (with widths from 1 to 4 mm) during brine and oil flow after placement. Regardless of gel age before placement, very little gel washed out from the fractures during brine or oil flow. However, increased brine or oil flow rate and cyclic injection of oil and water significantly decreased the level of permeability reduction. A particular need exists for gels that can plug large apertures (e.g., wide fractures and vugs). Improved mechanical strength and stability were demonstrated (in 1- to 4-mm-wide fractures) for a gel that contained a combination of high- and low-molecular weight polymers. This gel reduced the flow capacity of 2- and 4-mm-wide fractures by 260,000. In a 1-mm-wide fracture, it withstood 26 psi/ft without allowing any brine flow through the fracture. Cr(III)-acetate-HPAM gels exhibited disproportionate permeability reduction in fractures. The effect was most pronounced when the gel was placed as gelant or partially formed gels. The effect occurred to a modest extent with concentrated gels and with gels that were ''fully formed'' when placed. The effect was not evident in tubes. We explored swelling polymers for plugging fractures. Polymer suspensions were quickly prepared and injected. In concept, the partially dissolved polymer would lodge and swell to plug the fracture. For three types of swelling polymers, behavior was promising. However, additional development is needed before their performance will be superior to that of conventional gels.

Randall S. Seright

2003-09-01

250

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

251

Gel immobilization of acrylamide-modified single-stranded DNA template for pyrosequencing.  

PubMed

A novel two-step process was developed to prepare ssDNA templates for pyrosequencing. First, PCR-amplified DNA templates modified with an acrylamide group and acrylamide monomers were copolymerized in 0.1 M NaOH solution to form polyacrylamide gel spots. Second, ssDNA templates for pyrosequencing were prepared by removing electrophoretically unbound complementary strands, unmodified PCR primers, inorganic pyrophosphate (PPi), and excess deoxyribonucleotides under alkali conditions. The results show that the 3-D polyacrylamide gel network has a high immobilization capacity and the modified PCR fragments are efficiently captured. After electrophoresis, gel spots copolymerized from 10 microL of the crude PCR products and the acrylamide monomers contain template molecules on the order of pmol, which generate enough light to be detected by a regular photomultiplier tube. The porous structure of gel spots facilitated the fast transportation of the enzyme, dNTPs and other reagents, and the solution-mimicking microenvironment guaranteed polymerase efficiency for pyrosequencing. Successful genotyping from the crude PCR products was demonstrated. This method can be applied in any laboratory; it is cheap, fast, simple, and has the potential to be incorporated into a DNA-chip format for high-throughput pyrosequencing analysis. PMID:17487922

Xiao, Pengfeng; Huang, Huan; Zhou, Guohua; Lu, Zuhong

2007-06-01

252

Cytoplasmic polyhedrosis virus classification by electropherotype; validation by serological analyses and agarose gel electrophoresis.  

PubMed

Serological analyses of several different cytoplasmic polyhedrosis viruses (CPVs), including two type 1 CPVs from Bombyx mori, type 1 CPV from Dendrolimus spectabilis, type 12 CPV from Autographa gamma, type 2 CPV from Inachis io, type 5 CPV from Orgyia pseudotsugata and type 5 CPV from Heliothis armigera, demonstrated a close correlation between the antigenic properties of the polyhedrin or virus particle structural proteins and the genomic dsRNA electropherotypes. The dsRNAs of these viruses were analysed by electrophoresis in 3% and 10% polyacrylamide gels with a discontinuous Tris-HCl/Tris-glycine buffer system or by 1% agarose gel electrophoresis using a continuous Tris-acetate-EDTA buffer system. Electrophoretic analysis in agarose gels was found to be the most suitable for the classification of CPV isolates into electropherotypes, and the results obtained showed a close correlation with the observed antigenic relationships between different virus isolates. However, electrophoretic analysis in 10% polyacrylamide gels was most sensitive for the detection of intra-type variation and the presence of mixed virus isolates. PMID:2499658

Mertens, P P; Crook, N E; Rubinstein, R; Pedley, S; Payne, C C

1989-01-01

253

Modeling chemoresponsive polymer gels.  

PubMed

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

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

2014-01-01

254

Native American Journalists Association  

NSDL National Science Digital Library

The Native American Journalists Association (NAJA) is based on the campus of the University of Oklahoma in Norman, OK. NAJA was started in 1984 in order to improve the communications among Native people as well as between Native people and the public. Visitors can click on the "Resources" tab near the top of the page to view, among other things, links to "Job Opportunities", "Internships/Fellowships", and "Publications". Free downloadable versions of "The Reading Red Report" from 2002, 2003, and 2007 can be accessed in the "Publications" link. The 2007 Report gives the visitor the opportunity to see some of the research that NAJA has done on how Natives are depicted in the mainstream newspapers of areas with the highest population of Native peoples. The "Media Links" link, also under the "Resources" tab, has a wealth of information regarding media that would be helpful for any journalists or aspiring journalists. Some of the links include "Journalism Centers", "Journalism Libraries", "Job Sites", and "News Research". Under the "Programs" tab, there is a link to "Students" that has various resources for those pursuing scholarships, internships or finding student chapters of NAJA.

255

A gel probe equilibrium sampler for measuring arsenic porewater profiles and sorption gradients in sediments: I. Laboratory development  

USGS Publications Warehouse

A gel probe equilibrium sampler has been developed to study arsenic (As) geochemistry and sorption behavior in sediment porewater. The gels consist of a hydrated polyacrylamide polymer, which has a 92% water content. Two types of gels were used in this study. Undoped (clear) gels were used to measure concentrations of As and other elements in sediment porewater. The polyacrylamide gel was also doped with hydrous ferric oxide (HFO), an amorphous iron (Fe) oxyhydroxide. When deployed in the field, HFO-doped gels introduce a fresh sorbent into the subsurface thus allowing assessment of in situ sorption. In this study, clear and HFO-doped gels were tested under laboratory conditions to constrain the gel behavior prior to field deployment. Both types of gels were allowed to equilibrate with solutions of varying composition and re-equilibrated in acid for analysis. Clear gels accurately measured solution concentrations (??1%), and As was completely recovered from HFO-doped gels (??4%). Arsenic speciation was determined in clear gels through chromatographic separation of the re-equilibrated solution. For comparison to speciation in solution, mixtures of As(III) and As(V) adsorbed on HFO embedded in gel were measured in situ using X-ray absorption spectroscopy (XAS). Sorption densities for As(III) and As(V) on HFO embedded in gel were obtained from sorption isotherms at pH 7.1. When As and phosphate were simultaneously equilibrated (in up to 50-fold excess of As) with HFO-doped gels, phosphate inhibited As sorption by up to 85% and had a stronger inhibitory effect on As(V) than As(III). Natural organic matter (>200 ppm) decreased As adsorption by up to 50%, and had similar effects on As(V) and As(III). The laboratory results provide a basis for interpreting results obtained by deploying the gel probe in the field and elucidating the mechanisms controlling As partitioning between solid and dissolved phases in the environment. ?? 2008 American Chemical Society.

Campbell, K.M.; Root, R.; O'Day, P. A.; Hering, J.G.

2008-01-01

256

Polyacrylamide treatments for reducing seepage in soil-lined reservoirs: A field evaluation  

Technology Transfer Automated Retrieval System (TEKTRAN)

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...

257

PECTIN AND POLYACRYLAMIDE COMPOSITE HYDROGELS: EFFECT OF PECTIN ON STRUCTURAL AND DYNAMIC MECHANICAL PROPERTIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Composite hydrogels of pectin and polyacrylamide were synthesized and evaluated by scanning electron microscopy, atomic force microscopy, light microscopy, and by dynamic mechanical analysis. The cross-linking polymerization of acrylamide in pectin solution resulted in a composite having a macropo...

258

Toxicity of anionic polyacrylamide formulations when used for erosion control in agriculture  

Technology Transfer Automated Retrieval System (TEKTRAN)

Addition of anionic polyacrylamide (PAM) to agricultural irrigation water can dramatically reduce erosion of soils. However, the toxicity of PAM to aquatic life, while often claimed to be low, has not been thoroughly evaluated. Five PAM formulations, including two oil-based products, one water-based...

259

SOIL & WATER MANAGEMENT & CONSERVATION Soil Factors Infl uencing Suspended Sediment Flocculation by Polyacrylamide  

Microsoft Academic Search

Turbidity in stormwater runoff may be treated with polyacrylamide (PAM) to fl occulate suspended sediment, but the relationships between PAM properties and those of the suspended sediment have not been widely studied. Our objective was to determine how soil physical and chemical properties affected fl occulation by PAMs with a variety of characteristics. Subsoil materials were collected from 13 active

Richard A. McLaughlin; Nathanael Bartholomew

260

Erosion control practices integrated with polyacrylamide for nutrient reduction in rill irrigation runoff  

Microsoft Academic Search

The objective of this research was to assess soil conservation practices for improving water quality of return flows from rill irrigation in the Yakima River Basin, Washington, by combining patch application of polyacrylamide (PAM) with an additional erosion control practice. A 2-year field study was conducted that combined PAM with (1) check dams, (2) surge irrigation, (3) surface drains, and

A. A. Szögi; B. G. Leib; C. A. Redulla; R. G. Stevens; G. R. Mathews; D. A. Strausz

2007-01-01

261

Carbon and nitrogen stable isotope ratios can estimate anionic polyacrylamide degradation in soil  

Technology Transfer Automated Retrieval System (TEKTRAN)

Water soluble anionic polyacrylamide (PAM) is a highly effective erosion-preventing and infiltration-enhancing polymer, when applied at rates of 1 to 10 g/m-3 in furrow irrigation water. PAM degradation has not directly been measured in soil or water. Natural abundance of the carbon (13C/12C) isoto...

262

Polyacrylamide effects on aggregate and structure stability of soils with different clay mineralogy  

Technology Transfer Automated Retrieval System (TEKTRAN)

Adding anionic polyacrylamide (PAM) to soils stabilizes existing aggregates and improves bonding between and aggregation of soil particles. However, the dependence of PAM efficacy as an aggregate stabilizing agent with soils having different clay mineralogy has not been studied. Sixteen soil samples...

263

Soil aggregate stability as affected by clay mineralogy and polyacrylamide addition  

Technology Transfer Automated Retrieval System (TEKTRAN)

The addition of polyacrylamide (PAM) to soil leads to stabilization of existing aggregates and improved bonding between, and aggregation of adjacent soil particles However, the dependence of PAM efficacy as an aggregate stabilizing agent on soil-clay mineralogy has not been studied. Sixteen soil sam...

264

Comparison of Cationic and Unmodified Starches in Reactive Extrusion of Starch-Polyacrylamide Graft Copolymers  

Technology Transfer Automated Retrieval System (TEKTRAN)

Graft copolymers of starch and polyacrylamide (PAAm) were prepared using reactive extrusion in a corotating twin screw extruder. The effect of cationic starch modification was examined using unmodified and cationic dent starch (approximately 23% amylose) and waxy maize starch (approximately 2% amyl...

265

Nonlinear Strain Stiffening Is Not Sufficient to Explain How Far Cells Can Feel on Fibrous Protein Gels  

PubMed Central

Recent observations suggest that cells on fibrous extracellular matrix materials sense mechanical signals over much larger distances than they do on linearly elastic synthetic materials. In this work, we systematically investigate the distance fibroblasts can sense a rigid boundary through fibrous gels by quantifying the spread areas of human lung fibroblasts and 3T3 fibroblasts cultured on sloped collagen and fibrin gels. The cell areas gradually decrease as gel thickness increases from 0 to 150 ?m, with characteristic sensing distances of >65 ?m below fibrin and collagen gels, and spreading affected on gels as thick as 150 ?m. These results demonstrate that fibroblasts sense deeper into collagen and fibrin gels than they do into polyacrylamide gels, with the latter exhibiting characteristic sensing distances of <5 ?m. We apply finite-element analysis to explore the role of strain stiffening, a characteristic mechanical property of collagen and fibrin that is not observed in polyacrylamide, in facilitating mechanosensing over long distances. Our analysis shows that the effective stiffness of both linear and nonlinear materials sharply increases once the thickness is reduced below 5 ?m, with only a slight enhancement in sensitivity to depth for the nonlinear material at very low thickness and high applied traction. Multiscale simulations with a simplified geometry predict changes in fiber alignment deep into the gel and a large increase in effective stiffness with a decrease in substrate thickness that is not predicted by nonlinear elasticity. These results suggest that the observed cell-spreading response to gel thickness is not explained by the nonlinear strain-stiffening behavior of the material alone and is likely due to the fibrous nature of the proteins. PMID:23823219

Rudnicki, Mathilda S.; Cirka, Heather A.; Aghvami, Maziar; Sander, Edward A.; Wen, Qi; Billiar, Kristen L.

2013-01-01

266

Contemporary Native Art  

E-print Network

the Sacred Circles Fund and the Na­ tional Endowment for the Arts. Photos by Bobby Hansson. percentage of the spectators at the show were themselves Native Americans. Heed that fact well: native folks are culturally self-conscious, alert... an important post at the Smithsonian, but left that too to devote himself to making us see the beauty and diversity, not to say vitality, of current Indian art. Now his big book is out, and we are richer for it. Trained neither as ethnologist nor...

Levine, Stuart

1987-01-01

267

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.

268

Gel for simultaneous chemical imaging of anionic and cationic solutes using diffusive gradients in thin films.  

PubMed

We report on a novel gel based on diffusive gradients in thin films (DGT) for the simultaneous measurement of cations and anions and its suitability for high resolution chemical imaging by using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). The new high resolution mixed binding gel (HR-MBG) is based on zirconium-hydroxide and suspended particulate reagent-iminodiacetate (SPR-IDA) as resin materials which are embedded in an ether-based urethane polymer hydrogel. The use of this polymer hydrogel material allows the production of ultrathin, highly stable and tear-proof resin gel layers with superior handling properties compared to existing ultrathin polyacrylamide gels. The gel was characterized regarding its uptake kinetics, the anion and cation capacities, and the effects of pH, ionic strength, and aging on the performance of the HR-MBG. Our results demonstrate the capability of this novel gel for concomitant sampling of anions and cations. The suitability of this new gel type for DGT chemical imaging at submm spatial resolution in soils using LA-ICPMS is shown. 2D images of P, As, Co, Cu, Mn, and Zn distributions around roots of Zea mays L. demonstrate the new opportunities offered by the HR-MBG for high-resolution mapping of solute dynamics in soil and sediment hotspots, such as the rhizosphere, by simultaneous observation of anionic and cationic solute species. PMID:24256092

Kreuzeder, Andreas; Santner, Jakob; Prohaska, Thomas; Wenzel, Walter W

2013-12-17

269

A Pneumatic Device for Rapid Loading of DNA Sequencing?Gels  

PubMed Central

This work describes the design and construction of a device that facilitates the loading of DNA samples onto polyacrylamide gels for detection in the Perkin Elmer/Applied Biosystems (PE/ABI) 373 and 377 DNA sequencing instruments. The device is mounted onto the existing gel cassettes and makes the process of loading high-density gels less cumbersome while the associated time and errors are reduced. The principle of operation includes the simultaneous transfer of the entire batch of samples, in which a spring-loaded air cylinder generates positive pressure and flexible silica capillaries transfer the samples. A retractable capillary array carrier allows the delivery ends of the capillaries to be held up clear of the gel during loader attachment on the gel plates, while enabling their insertion in the gel wells once the device is securely mounted. Gel-loading devices capable of simultaneously transferring 72 samples onto the PE/ABI 373 and 377 are currently being used in our production sequencing groups while a 96-sample transfer prototype undergoes testing. PMID:9582197

Panussis, Dimitrios A.; Cook, Mark W.; Rifkin, Lisa L.; Snider, Jacqueline E.; Strong, Joseph T.; McGrane, Rebecca M.; Wilson, Richard K.; Mardis, Elaine R.

1998-01-01

270

Synthesis of p-and n-type Gels Doped with Ionic Charge Carriers.  

PubMed

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 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. PMID:20672071

Alveroglu, E; Yilmaz, Y

2010-03-01

271

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

272

Native plant diversity increases herbivory to non-natives.  

PubMed

There is often an inverse relationship between the diversity of a plant community and the invasibility of that community by non-native plants. Native herbivores that colonize novel plants may contribute to diversity-invasibility relationships by limiting the relative success of non-native plants. Here, we show that, in large collections of non-native oak trees at sites across the USA, non-native oaks introduced to regions with greater oak species richness accumulated greater leaf damage than in regions with low oak richness. Underlying this trend was the ability of herbivores to exploit non-native plants that were close relatives to their native host. In diverse oak communities, non-native trees were on average more closely related to native trees and received greater leaf damage than those in depauperate oak communities. Because insect herbivores colonize non-native plants that are similar to their native hosts, in communities with greater native plant diversity, non-natives experience greater herbivory. PMID:25232143

Pearse, Ian S; Hipp, Andrew L

2014-11-01

273

Use of an acid-labile surfactant as an SDS substitute for gel electrophoresis and proteomic analysis.  

PubMed

Modern protein identification and analysis relies largely on proteolytic in-gel digestion of proteins separated during polyacrylamide gel electrophoresis (PAGE) followed by mass spectrometric (MS) measurement of the extracted peptides. Sodium dodecyl sulfate (SDS) is routinely used in nonnative PAGE. However, SDS can interfere with MS. We report the use of an acid-labile surfactant (ALS-I) in place of SDS. ALSI is a long chain derivative of 1,3-dioxolane sodium propyloxy sulfate and has similar denaturing and electrophoretic properties as SDS, but it decomposes at low pH and enhances MS detection of proteins. PMID:19498958

Zeller, Martin; Brown, Elizabeth K; Bouvier, Edouard S P; König, Simone

2002-03-01

274

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

275

Detection and characterization of heparin-binding proteins with a gel overlay procedure  

SciTech Connect

The binding of {sup 125}I-labeled derivatives of heparin has been used by several investigators to identify heparin-binding fragments of different heparin-binding proteins. In this report we utilize the procedure described by J.W. Smith and D.J. Knauer (1987, Anal. Biochem. 160, 105-114) to produce {sup 125}I-fluorescein-heparin. Using this derivative, we compare the use of gel overlay procedures with Western blot procedures for the detection of heparin-binding proteins following polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. We show that the gel overlay procedure is a relatively simple and sensitive method for visualizing heparin-binding proteins. In addition, we use the procedure to characterize the heparin-binding properties of heparin-binding growth factor 1 (acidic fibroblast growth factor) with synthetic peptide competitors and site-directed mutants of the growth factor.

Mehlman, T.; Burgess, W.H. (American Red Cross, Rockville, MD (USA))

1990-07-01

276

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...

277

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...

278

Native American Case Studies  

NSDL National Science Digital Library

The Native American Case Studies collection includes more than 80 original, research-based teaching cases focusing on contemporary issues in Indian Country. Teaching notes accompany each case. These can be downloaded and used at no cost. Additional website resources include information on teaching with cases and assessment. Guidelines for submitting cases are also available.

The Evergreen State College

279

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.

280

Native Westslope Cutthroat Trout  

USGS Multimedia Gallery

Native westslope cutthroat trout swim in the north fork of the Flathead River in northwestern Montana. The region is recognized as a range-wide stronghold for genetically pure westslope cutthroat trout. However, rainbow trout invasion and hybridization threatens these p...

281

Native American Literature.  

ERIC Educational Resources Information Center

Designed to accommodate a semester course in Native American Literature for secondary students, this teacher's guide includes a general introduction, a statement of the philosophy and goals upon which it is predicated, a nine-week block on post-Columbian literature, a nine-week block on oral literature, separate appendices for each block, a…

Porter, C. Fayne; And Others

282

Native Americans: Subject Guide.  

ERIC Educational Resources Information Center

This annotated subject guide lists reference material that deals with Native Americans and is available in the Arizona State University Libraries. Entries were published 1933-98, but mostly in the 1980s-90s. The guide is not comprehensive, but rather a selective list of resources useful for researching a topic in a variety of fields. The guide…

Bonanni, Mimmo; Etter, Patricia A.

283

NEW ZEALAND'S NATIVE GREEN  

E-print Network

NEW ZEALAND'S NATIVE GREEN MISTLETOES What can you do to help? Many green mistletoe populations mistletoes threatened? Although Ileostylus and Tupeia are the most common mistletoes in New Zealand, they are currently declining in many areas, particularly in the North Island. Browsing by possums, habitat

Canterbury, University of

284

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

285

Native Westslope Cutthroat Trout  

USGS Multimedia Gallery

Native westslope cutthroat trout swim in the north fork of the Flathead River in northwestern Montana. This region is recognized as a range-wide stronghold for genetically pure westslope cutthroat trout. However, rainbow trout invasion and hybridization threatens these ...

286

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. PMID:21806932

Long, Rong; Hall, Matthew S.; Wu, Mingming; Hui, Chung-Yuen

2011-01-01

287

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

288

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.

2011-08-05

289

Native Peoples-Native Homelands Climate Change Workshop: Lessons Learned  

NASA Technical Reports Server (NTRS)

The Native Peoples-Native Homelands Climate Change Workshop was held on October 28 through November 01,1998, as part of a series of workshops being held around the U.S. to improve the understanding of the potential consequences of climate variability and change for the Nation. This workshop was specifically designed by Native Peoples to examine the impacts of climate change and extreme weather variability on Native Peoples and Native Homelands from an indigenous cultural and spiritual perspective and to develop recommendations as well as identify potential response actions. The workshop brought together interested Native Peoples, representatives of Tribal governments, traditional elders, Tribal leaders, natural resource managers, Tribal College faculty and students, and climate scientists fiom government agencies and universities. It is clear that Tribal colleges and universities play a unique and critical role in the success of these emerging partnerships for decision-making in addition to the important education function for both Native and non-Native communities such as serving as a culturally-appropriate vehicle for access, analysis, control, and protection of indigenous cultural and intellectual property. During the discussions between scientists and policy-makers from both Native and non-Native communities, a number of important lessons emerged which are key to building more effective partnerships between Native and non-Native communities for collaboration and decision-making for a more sustainable future. This talk summarizes the key issues, recommendations, and lessons learned during this workshop.

Maynard, Nancy G.

2003-01-01

290

Crystallization from Gels  

NASA Astrophysics Data System (ADS)

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

Narayana Kalkura, S.; Natarajan, Subramanian

291

Conformance Improvement Using Gels  

SciTech Connect

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

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

2002-09-26

292

Cu(2+)-assisted two dimensional charge-mass double focusing gel electrophoresis and mass spectrometric analysis of histone variants.  

PubMed

Abundant isoforms and dynamic posttranslational modifications cause the separation and identification of histone variants to be experimentally challenging. To meet this need, we employ two-dimensional electrophoretic gel separation followed by mass spectrometric detection which takes advantage of the chelation of Cu(2+) with amino acid residues exposed on the surfaces of the histone proteins. Acid-extracted rat liver histones were first mixed with CuSO4 solution and then separated in one dimension with triton-acid-urea (TAU) gel electrophoresis and in a second dimension using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The separations result from both the changes in charge and mass upon Cu(2+) chelation. Identities of each separated gel bands were obtained by using matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS). It was found that the migration of H3 histone isoforms of rat liver is markedly affected by the use of Cu(2+) ions. PMID:25441888

Zhang, Wenyang; Tang, Xuemei; Ding, Mengjie; Zhong, Hongying

2014-12-10

293

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

294

Native Americans' Interest in Horticulture.  

ERIC Educational Resources Information Center

Focus groups arranged by local Native American Master Gardeners on two Minnesota reservations determined community interest in extension-horticulture programs. Topics of interest included food preservation and historical Native-American uses of plants. (SK)

Meyer, Mary Hockenberry

1999-01-01

295

Resources for Native Education Leaders  

NSDL National Science Digital Library

This resource guide lists institutions and programs, dissertations, articles, and books about Native American education leadership in Native organizations and communities. It also includes citations from Leadership Quarterly on the same subject.

Begaye, Tim

296

Amended final report on the safety assessment of polyacrylamide and acrylamide residues in cosmetics.  

PubMed

Polyacrylamide is a polymer of controllable molecular weight formed by the polymerization of acrylamide monomers available in one of three forms: solid (powder or micro beads), aqueous solution, or inverse emulsions (in water droplets coated with surfactant and suspended in mineral oil). Residual acrylamide monomer is likely an impurity in most Polyacrylamide preparations, ranging from <1 ppm to 600 ppm. Higher levels of acrylamide monomers are present in the solid form compared to the other two forms. Polyacrylamide is reportedly used in 110 cosmetic formulations, at concentrations ranging from 0.05% to 2.8%. Residual levels of acrylamide in Polyacrylamide can range from <.01% to 0.1%, although representative levels were reported at 0.02% to 0.03%. Because of the large sizes of Polyacrylamide polymers, they do not penetrate the skin. Polyacrylamide itself is not significantly toxic. For example, an acute oral toxicity study of Polyacrylamide in rats reported that a single maximum oral dose of 4.0 g/kg body weight was tolerated. In subchronic oral toxicity studies, rats and dogs treated with Polyacrylamide at doses up to 464 mg/kg body weight showed no signs of toxicity. Several 2-year chronic oral toxicity studies in rats and dogs fed diets containing up to 5% Polyacrylamide had no significant adverse effects. Polyacrylamide was not an ocular irritant in animal tests. No compound-related lesions were noted in a three-generation reproductive study in which rats were fed 500 or 2000 ppm Polyacrylamide in their diet. Polyacrylamide was not carcinogenic in several chronic animal studies. Human cutaneous tolerance tests performed to evaluate the irritation of 5% (w/w) Polyacrylamide indicated that the compound was well tolerated. Acrylamide monomer residues do penetrate the skin. Acrylamide tested in a two-generation reproductive study at concentrations up to 5 mg/kg day(- 1) in drinking water, was associated with prenatal lethality at the highest dose, with evidence of parental toxicity. The no adverse effects level was close to the 0.5 mg/kg day(- 1) dose. Acrylamide tested in a National Toxicology Program (NTP) reproductive and neurotoxicity study at 3, 10, and 30 ppm produced no developmental or female reproductive toxicity. However, impaired fertility in males was observed, as well as minimal neurotoxic effects. Acrylamide neurotoxicity occurs in both the central and peripheral nervous systems, likely through microtubule disruption, which has been suggested as a possible mechanism for genotoxic effects of acrylamide in mammalian systems. Acrylamide was genotoxic in mammalian in vitro and in vivo assays. Acrylamide was a tumor initiator, but not an initiator/promoter, in two different mouse strains at a total dose of 300 mg/kg (6 doses over 2 weeks) resulting in increased lung adenomas and carcinomas without promotion. Acrylamide was tested in two chronic bioassays using rats. In one study, increased incidence of mammary gland tumors, glial cell tumors, thyroid gland follicular tumors, oral tissue tumors, uterine tumors and clitoral gland tumors were noted in female rats. In male rats, the number of tumors in the central nervous system (CNS), thyroid gland, and scrotum were increased with acrylamide exposure. In the second study, using higher doses and a larger number of female rats, glial cell tumors were not increased, nor was there an increase in mammary gland, oral tissue, clitoral gland, or uterine tumors. Tumors of the scrotum in male rats were confirmed, as were the thyroid gland follicular tumors in males and females. Taken together, there was a dose-dependent, but not statistically significant, increase in the number of astrocytomas. Different human lifetime cancer risk predictions have resulted, varying over three orders of magnitude from 2 x 10(- 3) to 1.9 x 10(- 6). In the European Union, acrylamide has been limited to 0.1 ppm for leave-on cosmetic products and 0.5 ppm for other cosmetic products. An Australian risk assessment suggested negligible health risks from acrylamide in cosmetics. The Cosmetic

2005-01-01

297

Genetic conservation of native trees  

E-print Network

and implications of genetic variation within the gene-pools of British native tree species. It was acknowledged at the beginning of 2003, now cover a much wider range of British native tree species than was previously the case: 31 species relevant to forestry in Britain and 15 of these are native. The FC is a member of EUFORGEN

298

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

SciTech Connect

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 [State University of Tetovo, Faculty of Natural Science and Mathematics, 1200 Tetovo (Macedonia, The Former Yugoslav Republic of); Sen, Murat; Gueven, Olgun [Hacettepe University, Department of Chemistry, Polymer Chemistry Division, 06532, Beytepe, Ankara (Turkey); Rendevski, Stojan [Institute of Physics, Faculty of Natural Science and Mathematics, University 'Ss Cyril and Methodius', Skopje (Macedonia, The Former Yugoslav Republic of)

2007-04-23

299

Water and Erosion Management with Multiple Applications of Polyacrylamide in Furrow Irrigation  

Microsoft Academic Search

Polyacrylamide (PAM) in furrow irrigation water eliminates 94% of runoff sediment. Higher infiltration (15-50%) can result in upper- field uverirrigation. We hypothesized that PAM would lengthen ad- vance time, but that interactions with flow rate and wheel-track (WT) Ihrrows would occur, influencing erosion and infiltration with poten- tial for improved water management. A 2-yr study conducted on 1.5% slope Portneuf

R. E. Sojka; R. D. Lentz; D. T. Westermann

1998-01-01

300

Impact of polyacrylamide on surface properties of solutions of chlorides of alkylpyridinium during their removal  

Microsoft Academic Search

It has been shown that in diluted aqueous solutions of alkylpyridinium chlorides (APC) containing polyacrylamide (PAA) one\\u000a can detect synergism of their effect on surface tension. Maximum manifestation of synergism in the course of adsorption of\\u000a components occurs at their molar ratio nAPC: nPAA—1: 0.25. By design values of the minimal area falling at the COD-PAA particles in surface layers

E. A. Strel’tsova; I. V. Puzyreva; O. V. Volyuvach

2008-01-01

301

Identification of native foot-and-mouth disease virus non-structural protein 2C as a serological indicator to differentiate infected from vaccinated livestock  

Microsoft Academic Search

Cattle and pigs which have been vaccinated against foot-and-mouth disease can be distinguished from convalescent animals by radio-immunoprecipitation and sodium dodecyl sulphate polyacrylamide gel electrophoresis of the virus-induced proteins reacting with the respective sera. Baby hamster kidney cells infected with foot-and-mouth disease virus (fmdv) (serotype A24) were labelled with 35S-methionine and the virus-induced proteins were precipitated with sera from vaccinated

J Lubroth; F Brown

1995-01-01

302

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

303

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

304

NativeTech  

NSDL National Science Digital Library

Native Tech is an internet resource providing historical and contemporary information, including how-to's and references on indigenous ethno-technology and arts of Eastern Woodland Indian Peoples. The non-profit organization is "dedicated to removing the term primitive from discussions of Indian artifacts." Articles address topics such as Beads & Beadwork, Metalwork, Stonework and Tools, and features on games and toys, recipes, poetry and a Virtual Woodland Tour. Other features include internet links, discussion forums, Tribal News updates and information on upcoming events.

305

Transdermal delivery of paeonol using cubic gel and microemulsion gel  

PubMed Central

Background The aim of this study was to develop new systems for transdermal delivery of paeonol, in particular microemulsion gel and cubic gel formulations. Methods Various microemulsion vehicles were prepared using isopropyl myristate as an oil phase, polyoxyethylated castor oil (Cremophor® EL) as a surfactant, and polyethylene glycol 400 as a cosurfactant. In the optimum microemulsion gel formulation, carbomer 940 was selected as the gel matrix, and consisted of 1% paeonol, 4% isopropyl myristate, 28% Cremophor EL/polyethylene glycol 400 (1:1), and 67% water. The cubic gel was prepared containing 3% paeonol, 30% water, and 67% glyceryl monooleate. Results A skin permeability test using excised rat skins indicated that both the cubic gel and microemulsion gel formulations had higher permeability than did the paeonol solution. An in vivo pharmacokinetic study done in rats showed that the relative bioavailability of the cubic gel and microemulsion gel was enhanced by about 1.51-fold and 1.28-fold, respectively, compared with orally administered paeonol suspension. Conclusion Both the cubic gel and microemulsion gel formulations are promising delivery systems to enhance the skin permeability of paeonol, in particular the cubic gel. PMID:21904450

Luo, Maofu; Shen, Qi; Chen, Jinjin

2011-01-01

306

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

307

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.

308

Traditional West Coast Native Medicine  

PubMed Central

An important part of the complex culture of the Native people of Canada's Pacific coast is the traditional system of medicine each culture has developed. Population loss from epidemics and the influence of dominant European cultures has resulted in loss of many aspects of traditional medicine. Although some Native practices are potentially hazardous, continuation of traditional approaches to illness remains an important part of health care for many Native people. The use of “devil's club” plant by the Haida people illustrates that Native medicine has both spiritual and physical properties. Modern family practice shares many important foundations with traditional healing systems. PMID:21253031

Deagle, George

1988-01-01

309

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

310

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

311

Native Plants, Native Knowledge: Insights from Judy Bluehorse Skelton.  

ERIC Educational Resources Information Center

Judy Bluehorse Skelton is an herbalist of Native American descent who conducts field trips to identify plants and classroom activities to demonstrate their uses. She also works with Portland (Oregon) schools developing culturally appropriate strategies for presenting Native American content. She encourages students to look at events such as the…

Reed, Bracken

2003-01-01

312

Polyacrylamide-based phantoms as tissue substitute in experimental radiation physics  

SciTech Connect

Polyacrylamide-based tissue-equivalent phantoms simulating cortical bone and muscle are described. The equivalency is based upon similar elemental composition and density, and partial similarity in the morphology of bone. Satisfactory results were obtained when the phantoms were tested at low (20 keV) and high (15 MeV) gamma radiation. Applicability of this phantom material to neutron transport is discussed. The material can be molded and shaped and its composition is easily modified by altering the proportions of the constituents. Trace elements or radionuclides are easily added. Details of the physical and radiation characteristics of the formulated systems are given together with the manufacturing procedures.

Wielopolski, L.; Maryanski, M.; Washington, A.C.; Schidlovsky, G.; Cohn, S.H.; Reinstein, L.E.; Kalend, A.M.; Meek, A.B.

1985-11-01

313

Ceric ion initiated synthesis of polyacrylamide grafted oatmeal: Its application as flocculant for wastewater treatment.  

PubMed

Polyacrylamide grafted oatmeal (OAT-g-PAM) was synthesized by conventional method. The grafting of the PAM chains on the biomaterial backbone was confirmed through intrinsic viscosity study, FTIR spectroscopy, elemental analysis (C, H, N, S and O), SEM morphology and TGA study. The intrinsic viscosity of oatmeal appreciably improved on grafting of PAM chains, thus resulting grafted product with potential application as superior viscosifier. Further, flocculation efficacy of the graft copolymer was studied in coal fine suspension, kaolin suspension, iron-ore suspension and then in municipal wastewater through 'jar test' procedure. PMID:23499093

Bharti, Srijita; Mishra, Sumit; Sen, Gautam

2013-04-01

314

Verification of motion induced thread effect during tomotherapy using gel dosimetry  

NASA Astrophysics Data System (ADS)

The purpose of the study was to evaluate how breathing motion during tomotherapy (Accuray, CA, USA) treatment affects the absorbed dose distribution. The experiments were carried out using gel dosimetry and a motion device simulating respiratory-like motion (HexaMotion, ScandiDos, Uppsala, Sweden). Normoxic polyacrylamide gels (nPAG) were irradiated, both during respiratory-like motion and in a static mode. To be able to investigate interplay effects the static absorbed dose distribution was convolved with the motion function and differences between the dynamic and convolved static absorbed dose distributions were interpreted as interplay effects. The expected dose blurring was present and the interplay effects formed a spiral pattern in the lower dose volume. This was expected since the motion induced affects the preset pitch and the theoretically predicted thread effect may emerge. In this study, the motion induced thread effect was experimentally verified for the first time.

Edvardsson, Anneli; Ljusberg, Anna; Ceberg, Crister; Medin, Joakim; Ambolt, Lee; Nordström, Fredrik; Ceberg, Sofie

2015-01-01

315

Linear electrochemical gel actuators  

NASA Astrophysics Data System (ADS)

By using electroactive monomers it is possible to produce gels that respond to oxidation or reduction by swelling and deswelling in the presence of solvent. By the inclusion of an appropriate biasing element such as a spring, it is possible to produce linear, reversible actuation. The process can be driven electrochemically in a standard cell, with driving voltages under +/- 1 V. For many systems, the intrinsic conductivity of the gel, leading to poor or no performance. This can be overcome by blending conductive carbon nanotubes at 1% concentration, which give reasonable conductivity without affecting mechanical performance. Extensions of up to 40% are possible, against an external pressure of 30 kPa. The process is slow, taking up to 160 minutes per cycle due to slow ionic diffusion. The electrochemical cell can be cycled many times without degradation.

Goswami, Shailesh; McAdam, C. John; Hanton, Lyall R.; Moratti, Stephen C.

2011-11-01

316

Linear electrochemical gel actuators  

NASA Astrophysics Data System (ADS)

By using electroactive monomers it is possible to produce gels that respond to oxidation or reduction by swelling and deswelling in the presence of solvent. By the inclusion of an appropriate biasing element such as a spring, it is possible to produce linear, reversible actuation. The process can be driven electrochemically in a standard cell, with driving voltages under +/- 1 V. For many systems, the intrinsic conductivity of the gel, leading to poor or no performance. This can be overcome by blending conductive carbon nanotubes at 1% concentration, which give reasonable conductivity without affecting mechanical performance. Extensions of up to 40% are possible, against an external pressure of 30 kPa. The process is slow, taking up to 160 minutes per cycle due to slow ionic diffusion. The electrochemical cell can be cycled many times without degradation.

Goswami, Shailesh; McAdam, C. John; Hanton, Lyall R.; Moratti, Stephen C.

2012-04-01

317

Inhibition of hydroxyapatite formation in collagen gels by chondroitin sulphate.  

PubMed Central

Crystal growth in native collagen gels has been used to determine the role of extracellular matrix macromolecules in biological calcification phenomena. In this system, type I collagen gels containing sodium phosphate and buffered at pH 7.4 are overlayed with a solution containing CaCl2. Crystals form in the collagen gel adjacent to the gel-solution interface. Conditions were determined which permit the growth of crystals of hydroxyapatite [Ca10(PO4)6(OH)2]. At a Ca/P molar ratio of 2:1, the minimum concentrations of calcium and phosphate necessary for precipitation of hydroxyapatite are 10 mM and 5 mM, respectively. Under these conditions, precipitation is initiated at 18-24h, and is maximal between 24h and 6 days. Addition of high concentrations of chondroitin 4-sulphate inhibits the formation of hydroxyapatite in collagen gels; initiation of precipitation is delayed, and the final (equilibrium) amount of precipitation is decreased. Inhibition of hydroxyapatite formation requires concentrations of chondroitin sulphate higher than those required to inhibit calcium pyrophosphate crystal formation. Images Fig. 2. PMID:2990448

Hunter, G K; Allen, B L; Grynpas, M D; Cheng, P T

1985-01-01

318

Native Hawaiian Scholarship`Aha  

E-print Network

Native Hawaiian Scholarship`Aha Hawai`i Island Waimea Hawaiian Homestead Hall Tuesday, November 18 & Int. School Cafeteria Thursday, January 29, 2015 @ 6:00 pm Learn about scholarships available to Native Hawaiian college students. Meet with scholarship providers from: Kamehameha Schools, Keali

319

Proficiency and the Native Speaker.  

ERIC Educational Resources Information Center

Native speakers act as standard-providers, evaluators, and the evaluated in the development of oral proficiency interviews. Thus, proficiency guidelines cannot be accepted as valid until there is evidence that oral interviews and rating scales mirror the process of the native speaker, both in evaluating and in exhibiting proficiency. (CB)

Barnwell, David

1989-01-01

320

Native Americans: The First Campers.  

ERIC Educational Resources Information Center

Questions are presented to help camps determine if their usage of American Indian culture truly honors Native Americans. Camps that plan to use Indian lore should research the tribe's name, location, symbols, legends, and living habits. A 5-day program is presented for enhancing campers' understanding of Native peoples and their relationship to…

Dunn, Bonnie; Frebertshauser, Denise

2002-01-01

321

Alcohol abuse among Native Americans  

Microsoft Academic Search

Native Americans have experienced substantial problems with alcohol since its introduction to their culture by early European settlers. Epidemiological data indicate that elevated morbidity and mortality attributable to alcohol abuse among this population remain at epidemic levels. Adolescent drinking patterns and family and peer influences on alcohol use are examined. A multifactorial etiology is indicated in the origin of Native

Roland J. Lamarine

1988-01-01

322

Earth's Caretakers: Native American Lessons.  

ERIC Educational Resources Information Center

Written by Native American teachers and by teachers of Native Americans, this book presents examples of ways to learn respect for the Earth and its people. The hope is that students will learn to walk softly upon the Earth and to respect all living things. Lessons and activities engage elementary and middle school students in a four-step…

Nyberg, Lisa M., Ed.

323

Predicting bulk mechanical properties of cellularized collagen gels using multiphoton microscopy  

E-print Network

approached that of native connective tissues ($200 mg ml­1 ). Young's modulus (E) measurements from acellular largely determine bulk mechanical properties of colla- gen-rich connective tissues. The mechanical Fluorescence Mechanical properties a b s t r a c t Cellularized collagen gels are a common model in tissue

George, Steven C.

324

Vanishing native American dog lineages  

PubMed Central

Background Dogs were an important element in many native American cultures at the time Europeans arrived. Although previous ancient DNA studies revealed the existence of unique native American mitochondrial sequences, these have not been found in modern dogs, mainly purebred, studied so far. Results We identified many previously undescribed mitochondrial control region sequences in 400 dogs from rural and isolated areas as well as street dogs from across the Americas. However, sequences of native American origin proved to be exceedingly rare, and we estimate that the native population contributed only a minor fraction of the gene pool that constitutes the modern population. Conclusions The high number of previously unidentified haplotypes in our sample suggests that a lot of unsampled genetic variation exists in non-breed dogs. Our results also suggest that the arrival of European colonists to the Americas may have led to an extensive replacement of the native American dog population by the dogs of the invaders. PMID:21418639

2011-01-01

325

Adhesion of and to soil in runoff as influenced by polyacrylamide.  

PubMed

Polyacrylamide (PAM) is used in agriculture to reduce soil erosion and has been reported to reduce turbidity, nutrients, and pollutants in surface runoff water. The objective of this work was to determine the effect of PAM on the concentration of enteric bacteria in surface runoff by comparing four enteric bacteria representing phenotypically different motility and hydrophobicity from three soils. Results demonstrated that bacterial surface runoff was differentially influenced by the PAM treatment. Polyacrylamide treatment increased surface runoff for adhered and planktonic cells from a clay soil; significantly decreased surface runoff of adhered bacteria, while no difference was observed for planktonic bacteria from the sandy loam; and significantly decreased the surface runoff of planktonic cells, while no difference was observed for adhered bacteria from the clay loam. Comparing strains from a final water sample collected after 48 h showed a greater loss of while serovar Poona was almost not detected. Thus, (i) the PAM efficiency in reducing the concentration of enteric bacteria in surface runoff was influenced by soil type and (ii) variation in the loss of enteric bacteria highlights the importance of strain-specific properties that may not be captured with general fecal indicator bacteria. PMID:25602217

Bech, Tina B; Sbodio, Adrian; Jacobsen, Carsten S; Suslow, Trevor

2014-11-01

326

Dog pancreatic microsomal-membrane polypeptides analysed by two-dimensional gel electrophoresis.  

PubMed Central

The two-dimensional polyacrylamide-gel electrophoresis technique of O'Farrell [(1975) J. Biol. Chem 250, 4007-4021] was applied to resolve and analyse the polypeptide composition of dog pancreatic rough microsomal membranes, which were shown to be active in co-translational processing of preprolactin synthesized from pituitary mRNA in a translation system in vitro. About 100 polypeptides are resolved. Treatment of rough microsomal membranes with EDTA and high KCl concentration yielded membranes stripped of their ribosomes with retention of activity for translocation and processing. Stripped microsomal membranes showed a selective concentration of approximately 25 polypeptides in the membranes when analysed by two-dimensional polyacrylamide-gel electrophoresis. The two-dimensional electrophoretic profile was catalogued into polypeptides that are glycoproteins, those that contain free thiol groups disposed at the cytosolic surface of microsomal vesicles and those that are of secretory origin but have been entrapped in the microsomal preparation. Several secretory components, including amylase, procarboxypeptidases, lipase and anionic trypsinogen, were tentatively identified among the microsomal polypeptides. The rough and stripped microsomal membranes from dog pancreas show a characteristic set of seven major acidic polypeptides, which are also identifiable in microsomal-membrane preparations isolated from dog liver and rat liver. One of these polypeptides was identified as protein disulphide-isomerase (EC 5.3.4.1). Images Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. PMID:6696719

Kaderbhai, M A; Austen, B M

1984-01-01

327

Association Study between BDNF Gene Polymorphisms and Autism by Three-Dimensional Gel-Based Microarray  

PubMed Central

Single nucleotide polymorphisms (SNPs) are important markers which can be used in association studies searching for susceptible genes of complex diseases. High-throughput methods are needed for SNP genotyping in a large number of samples. In this study, we applied polyacrylamide gel-based microarray combined with dual-color hybridization for association study of four BDNF polymorphisms with autism. All the SNPs in both patients and controls could be analyzed quickly and correctly. Among four SNPs, only C270T polymorphism showed significant differences in the frequency of the allele (?2 = 7.809, p = 0.005) and genotype (?2 = 7.800, p = 0.020). In the haplotype association analysis, there was significant difference in global haplotype distribution between the groups (?2 = 28.19, p = 3.44e-005). We suggest that BDNF has a possible role in the pathogenesis of autism. The study also show that the polyacrylamide gel-based microarray combined with dual-color hybridization is a rapid, simple and high-throughput method for SNPs genotyping, and can be used for association study of susceptible gene with disorders in large samples. PMID:19582215

Cheng, Lu; Ge, Qinyu; Xiao, Pengfeng; Sun, Beili; Ke, Xiaoyan; Bai, Yunfei; Lu, Zuhong

2009-01-01

328

75 FR 43198 - Alaska Native Claims Selection  

Federal Register 2010, 2011, 2012, 2013, 2014

...surface estate for certain lands to Aleknagik Natives Limited, pursuant to the Alaska Native Claims Settlement Act. The subsurface estate in these lands will be conveyed to Bristol Bay Native Corporation when the surface estate is conveyed to...

2010-07-23

329

34 CFR 300.29 - Native language.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 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...

2010-07-01

330

34 CFR 300.29 - Native language.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2010-07-01 true 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...

2011-07-01

331

50 CFR 18.23 - Native exemptions.  

Code of Federal Regulations, 2014 CFR

...is sold (A) in an Alaskan Native village or town or (B) to an Alaskan Native for his consumption. ...the Secretary determines any species or stock of marine mammals...or collected by an Alaskan Native for subsistence purposes...

2014-10-01

332

Probing mechanical properties of fully hydrated gels and biological tissues.  

PubMed

A longstanding challenge in accurate mechanical characterization of engineered and biological tissues is maintenance of both stable sample hydration and high instrument signal resolution. Here, we describe the modification of an instrumented indenter to accommodate nanomechanical characterization of biological and synthetic tissues in liquid media, and demonstrate accurate acquisition of force-displacement data that can be used to extract viscoelastoplastic properties of hydrated gels and tissues. We demonstrate the validity of this approach via elastoplastic analysis of relatively stiff, water-insensitive materials of elastic moduli E>1000 kPa (borosilicate glass and polypropylene), and then consider the viscoelastic response and representative mechanical properties of compliant, synthetic polymer hydrogels (polyacrylamide-based hydrogels of varying mol%-bis crosslinker) and biological tissues (porcine skin and liver) of E<500 kPa. Indentation responses obtained via loading/unloading hystereses and contact creep loading were highly repeatable, and the inferred E were in good agreement with available macroscopic data for all samples. As expected, increased chemical crosslinking of polyacrylamide increased stiffness (E40 kPa) and decreased creep compliance. E of porcine liver (760 kPa) and skin (222 kPa) were also within the range of macroscopic measurements reported for a limited subset of species and disease states. These data show that instrumented indentation of fully immersed samples can be reliably applied for materials spanning several orders of magnitude in stiffness (E=kPa-GPa). These capabilities are particularly important to materials design and characterization of macromolecules, cells, explanted tissues, and synthetic extracellular matrices as a function of spatial position, degree of hydration, or hydrolytic/enzymatic/corrosion reaction times. PMID:18922534

Constantinides, Georgios; Kalcioglu, Z Ilke; McFarland, Meredith; Smith, James F; Van Vliet, Krystyn J

2008-11-14

333

Development and optimization of a 2-hydroxyethylacrylate MRI polymer gel dosimeter  

NASA Astrophysics Data System (ADS)

In this study, radiation induced changes in a polymer gel dosimeter manufactured using 2-hydroxyethylacrylate (HEA) and N,N'-methylene-bisacrylamide (BIS) were investigated using magnetic resonance imaging (MRI) and FT-Raman spectroscopy. The variation in magnetic resonance relaxation time (T2) with absorbed dose was modelled assuming fast exchange of magnetization. Overall good agreement between the model and experimental data was obtained. However, comparison with FT-Raman data suggests that not all the protons attached to the polymer contribute to the relaxation process. Furthermore, for certain compositions improved agreement with experimental data was achieved when a lower fraction of polymer protons available for exchange with water was assumed in the low dose region. This indicates that the T2 value is influenced by the composition and topology of the formed polymer, which may vary with absorbed dose. The concept of percentage dose resolution (DpDgr,%) was introduced to enable optimization of gel compositions for use in relative dosimetry applications. This concept was applied to demonstrate the effects of varying the gelatine concentration, the total fraction of monomer/crosslinker (%T) and the relative fraction of crosslinker (%C) on gel performance in HEA gels as well as compare the performance of HEA and a standard polyacrylamide gel (PAG). The percentage dose resolution was improved for all HEA gels compared to the PAG dosimeter containing 3% acrylamide and 3% BIS. Increasing the total concentration of monomer was shown to have the largest single effect. In the range of doses of interest for clinical radiation therapy, DpDgr,% for the optimal HEA gel (4% HEA, 4% BIS) was lower than 2.3%, compared to 3.8% for the PAG dosimeter.

Gustavsson, H.; Bäck, S. Å. J.; Lepage, M.; Rintoul, L.; Baldock, C.

2004-01-01

334

Clarification Procedure for Gels  

NASA Technical Reports Server (NTRS)

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

Barber, Patrick G.; Simpson, Norman R.

1987-01-01

335

High transparent shape memory gel  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

336

Gel for retarding water flow  

SciTech Connect

A process is described for forming, in situ, a gel in a porous structure comprising: introducing an effective amount of a gel-forming composition into pores of a porous structure; and allowing the gel-forming composition to form a gel in the pores. The thusly formed gel is capable of being formed by reacting an aqueous solution comprising a first substance selected from the group consisting of polyvinyl alcohols, polyvinyl alcohol copolymers, and mixtures thereof. A second substance comprises aldehyde operable for effecting a crosslinking reaction with the first substance, wherein the total amount of aldehyde is from about 0.005 to about 2.5% of the weight of the gel.

Marrocco, M.L.

1987-05-12

337

Polyoxometalate-based Supramolecular Gel  

PubMed Central

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

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

2013-01-01

338

Polyoxometalate-based Supramolecular Gel  

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

339

Gel polymer electrolytes for batteries  

DOEpatents

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

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

2014-11-18

340

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

341

A Native American Theatre Ensemble  

ERIC Educational Resources Information Center

The ceremonial rituals American Indians have practiced for centuries are uncontestable testimony to how strongly they respond to theatre. These rituals, a pure and functional form of dramatic art, are practiced today by a Native American theater group. (FF)

Brown, Kent R.

1973-01-01

342

A pH effect in the HPSEC separation of polyacrylamide-based copolymers  

SciTech Connect

This paper reports on four polyacrylamide-based samples, having the same nominal molecular weight and molecular weight distribution, characterized by HPSEC using two column sets and a mobile phase of phosphate buffer. Depending upon the pH, the separations demonstrate that the systematic differences between samples are influenced by the level of anionic sites along the polymer chain. It is found that the HPSEC elution profiles of these samples are reversed when the pH is changed from 2.2 to 7.0. The anionicity of the samples ranges from less than 0.5 mole % carboxyl content (the homopolymer of acrylamide) to 33.0 mole %. Capillary viscometry data support these findings in the two solvent media, indicating that no adsorption effects prevail in the chromatography. Static and on-line low angle laser light scattering (LALLS) data on the homopolymer of acrylamide also suggest that no adsorption or degradation is occurring in the chromatographic process.

Papazian, L.A. (American Cyanamid Co., Chemical Research Div., Stamford, CT (US))

1990-01-01

343

Synthesis and properties of immobilized pectinase onto the macroporous polyacrylamide microspheres.  

PubMed

Pectinase was covalently immobilized onto the macroporous polyacrylamide (PAM) microspheres synthesized via an inverse suspension polymerization approach, resulting in 81.7% immobilization yield. The stability of the macroporous PAM support, which has a large surface area, is not impeded by the adsorbed proteins despite the fact that up to 296.3 mg of enzyme is immobilized per gram of the carrier particles. The immobilized enzyme retained more than 75% of its initial activity over 30 days, and the optimum temperature/pH also increased to the range of 50-60 °C/3.0-5.0. The immobilized enzyme also exhibited great operational stability, and more than 75% residual activity was observed after 10 batch reactions. The kinetics of a model reaction catalyzed by the immobilized pectinase was finally investigated. Moreover, the immobilized pectinase could be recovered by centrifuging and showed durable activity at the process of recycle. PMID:21341670

Lei, Zhongli; Jiang, Qin

2011-03-23

344

The Use of Polyacrylamide as a Selective Depressant in the Separation of Chalcopyrite and Galena  

NASA Astrophysics Data System (ADS)

High molecular weight polyacrylamide (PAM) was tested as a potential selective depressant in the differential flotation separation of galena and chalcopyrite using potassium ethyl xanthate (KEX) as a collector. In single mineral flotation, PAM depressed chalcopyrite while galena was floatable. Mechanism study indicated that PAM could adsorb on galena through hydrogen bonding, and on chalcopyrite through hydrogen bonding as well as ammonium-copper complexation. KEX could only break up the galena-PAM bonding. It is the combined use of PAM and KEX that caused the selectivity. In mineral mixture flotation, galena and chalcopyrite could be separated by PAM and KEX only after EDTA treatment of the mineral mixtures. Time of flight secondary ion mass spectrometric (ToF-SIMS) measurements indicated that when galena and chalcopyrite were present together in the suspension, PAM adsorbed on both galena and chalcopyrite. However, after prior treatment of the mineral mixture by EDTA, PAM mainly adsorbed on chalcopyrite.

Wang, Lei

345

Fate and efficacy of polyacrylamide applied in furrow irrigation: full-advance and continuous treatments.  

PubMed

Polyacrylamide (PAM) is applied to 400000 irrigated hectares annually in the USA to control irrigation-induced erosion, yet the fate of dissolved PAM applied in irrigation water is not well documented. We determined the fate of PAM added to furrow streams under two treatments: Initial-10, 10 mg L(-1) PAM product applied only during the initial hours of the irrigation, and Cont-1, 1.0 mg L(-1) PAM product applied continuously during the entire irrigation. The study measured PAM concentrations in 167-m-long PAM-treated furrow streams and along a 530-m tail ditch that received this runoff. Soil was Portneuf silt loam (coarse-silty, mixed, superactive, mesic Durinodic Xeric Haplocalcid) with 1.5% slope. Samples were taken at three times during the irrigations, both during and after PAM application. Polyacrylamide was adsorbed to soil and removed from solution as the streams traversed the soil-lined channels. The removal rate increased with stream sediment concentration. Stream sediment concentrations were higher when PAM concentrations were <2 mg L(-1) a.i., for early irrigations, and when untreated tributary flows combined with the stream. In these cases, PAM concentration decreased to undetectable levels over the flow lengths used in this study. When inflows contained >6 mg L(-1) PAM a.i., stream sediment concentrations were minimal and PAM concentrations did not change down the furrow, though they decreased to undetectable levels within 0.5 h after application ceased. One percent of applied PAM was lost in tail-ditch runoff. This loss could have been eliminated by treating only the furrow advance or not treating the last two irrigations. PMID:11931460

Lentz, Rodrick D; Sojka, Robert E; Mackey, Bruce E

2002-01-01

346

Native Hawaiian views on biobanking.  

PubMed

Genomic science represents a new frontier for health research and will provide important tools for personalizing health care. Biospecimen-based research is an important mechanism for expanding the genomic research capacity, and indigenous peoples are a target of biospecimen-based research due to their relative isolation and the potential to discover rare or unique genotypes. This study explored Native Hawaiian perceptions of and expectations for biobanking. Ten discussion groups were conducted with Native Hawaiians (N?=?92), who first heard a presentation on biobanking. Six themes emerged: (1) biobank governance by the Native Hawaiian community, (2) research transparency, (3) priority of Native Hawaiian health concerns, (4) leadership by Native Hawaiian scientists accountable to community, (5) re-consenting each time specimen is used, and (6) education of Native Hawaiian communities. Considered together, these findings suggest that biobanking should be guided by six principles that comprise "G.R.E.A.T. Research" (Governance, Re-consent, Education, Accountability, Transparency, Research priorities). These recommendations are being shared with biobanking facilities in Hawai'i as they develop protocols for biobanking participation, governance, and education. These findings also inform researchers and indigenous peoples throughout the world who are working on biobanking and genomic research initiatives in their nations. PMID:24683042

Tauali i, Maile; Davis, Elise Leimomi; Braun, Kathryn L; Tsark, JoAnn Umilani; Brown, Ngiare; Hudson, Maui; Burke, Wylie

2014-09-01

347

Removal of paraquat pesticide from aqueous solutions using a novel adsorbent material based on polyacrylamide and methylcellulose hydrogels  

Technology Transfer Automated Retrieval System (TEKTRAN)

This research studied the characteristics of poly(acrylamide) and methylcellulose (PAAm-MC) hydrogels as a novel adsorbent material for removal of pesticide paraquat, from aqueous solution, with potential applications in curbing environmental risk from such herbicides. PAAm-MC hydrogels with differe...

348

Developing a Native American Studies Program.  

ERIC Educational Resources Information Center

The development of Native American Studies (NAS) is an attempt at self-awareness and an exercise in self-determination. One area of concern in the development of a program for Native Americans is their high attrition rate in college. Specially designed programs for the Native American student could offer (1) Native American student orientation…

Whiteman, Henrietta V.

349

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

350

Nanocrystal/sol-gel nanocomposites  

SciTech Connect

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

Petruska, Melissa A. (Los Alamos, NM); Klimov, Victor L. (Los Alamos, NM)

2012-06-12

351

Nanocrystal/sol-gel nanocomposites  

DOEpatents

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

Petruska, Melissa A. (Los Alamos, NM); Klimov, Victor L. (Los Alamos, NM)

2007-06-05

352

Electromechanical nonionic gels  

NASA Astrophysics Data System (ADS)

The electrically induced bending of nonionic polyvinyl alcohol gels, bending over 90° within 100 ms, is the fastest motion in the field of electroactuation of polymers. This rapid bending produces initial mechanical vibrations followed by a durable displacement that contrasts highly with the relaxation observed with elastomer- and polyelectrolyte-based actuators. Here, we characterize the bending process using video imaging and laser detecting technology and establish a physical model for the electromechanical conversion, based on our observation of an induced solvent migration. Our results show excellent agreement between the measurements and calculations. This study provides general rules for understanding the electrically induced bending of isotropic dielectrics and may also shed light on nonmuscular biological engines.

Zheng, J.; Xu, C.; Hirai, T.

2008-02-01

353

Living bacteria in silica gels  

NASA Astrophysics Data System (ADS)

The encapsulation of enzymes within silica gels has been extensively studied during the past decade for the design of biosensors and bioreactors. Yeast spores and bacteria have also been recently immobilized within silica gels where they retain their enzymatic activity, but the problem of the long-term viability of whole cells in an inorganic matrix has never been fully addressed. It is a real challenge for the development of sol-gel processes. Generic tests have been performed to check the viability of Escherichia coli bacteria in silica gels. Surprisingly, more bacteria remain culturable in the gel than in an aqueous suspension. The metabolic activity of the bacteria towards glycolysis decreases slowly, but half of the bacteria are still viable after one month. When confined within a mineral environment, bacteria do not form colonies. The exchange of chemical signals between isolated bacteria rather than aggregates can then be studied, a point that could be very important for 'quorum sensing'.

Nassif, Nadine; Bouvet, Odile; Noelle Rager, Marie; Roux, Cécile; Coradin, Thibaud; Livage, Jacques

2002-09-01

354

Methylthymol blue in Fricke gels  

NASA Astrophysics Data System (ADS)

The initial trial of methylthymol blue (MTB) as a chelator for ferric iron in Fricke gel dosimeters, used for three-dimensional (3D) dosimetry in cancer radiotherapy, is reported. MTB is a structural analogue of the conventionally used xylenol orange (XO); however, the absorbance spectrum of the ferric-MTB complex is shifted to higher wavelengths, which should allow for lower amount of light scattering during gel scanning. In this study, two gelatin substrates, two sources of XO and one source of MTB have been compared. The MTB- containing gels exhibited similar dose response and diffusion coefficient to the XO-containing gels at their wavelengths of maximum absorption (620 and 585 nm, respectively). In addition, the MTB gels gave an excellent dose response at 633 nm, which is an important wavelength that is already used with other 3D dosimeters.

Penev, K. I.; Mequanint, K.

2015-01-01

355

Native Voices: Native Peoples' Concepts of Health and Illness  

NSDL National Science Digital Library

Understanding Native people's ideas about wellness and general health is a complex process, and this online exhibit does a good job of providing an introduction to the subject. Created by the National Library of Medicine (NLM), the website has an introductory video and welcome message from Donald A.B. Lindberg, MD, the director of the NLM. After this, visitors should click on the "Exhibition" tab. Here they can browse through four sections (such as "Healing Ways") to learn about the transformations of Native populations' ideas about health, death, and healers over the centuries. The "Timeline" tab provides a detailed look at events from 100,000 BC to the present day that have shaped Native peoples' perceptions of these related phenomena. The site is rounded out by a "Resources" area, which includes lesson plans and a list of suggested readings.

2012-01-20

356

Collapse of Gels in an Electric Field  

Microsoft Academic Search

An infinitesimal change in electric potential across a polyelectrolyte gel produces a discrete, reversible volume change. The volume of the collapsed gel can be several hundred times smaller than that of the swollen gel.

Toyoichi Tanaka; Izumi Nishio; Shao-Tang Sun; Shizue Ueno-Nishio

1982-01-01

357

Sonication-triggered instantaneous gel-to-gel transformation.  

PubMed

Two new peptide-based isomers containing cholesterol and naphthalic groups have been designed and synthesized. We found that the position of L-alanine in the linker could tune the gelation properties and morphologies. The molecule with the L-alanine residue positioned in the middle of the linker (1b) shows better gelation behavior than that with L-alanine directly linked to the naphthalimido moiety (1a). As a result, a highly thermostable organogel of 1b with a unique core-shell structure was obtained at high temperature and pressure in acetonitrile. Moreover, the gels of 1a and 1b could undergo an instantaneous gel-to-gel transition triggered by sonication. Ultrasound could break the core-shell microsphere of 1b and the micelle structure of 1a into entangled fibers. By studying the mechanism of the sonication-triggered gel-to-gel transition process of these compounds, it can be concluded that ultrasound has a variety of effects on the morphology, such as cutting, knitting, unfolding, homogenizing, and even cross-linking. Typically, ultrasound can cleave and homogenize pi-stacking and hydrophobic interactions among the gel molecules and then reshape the morphologies to form a new gel. This mechanism of morphology transformation triggered by sonication might be attractive in the field of material storage and controlled release. PMID:20572172

Yu, Xudong; Liu, Qian; Wu, Junchen; Zhang, Mingming; Cao, Xinhua; Zhang, Song; Wang, Qi; Chen, Liming; Yi, Tao

2010-08-01

358

Native Plant Master Program Announces 2012 Classes The Native Plant Master  

E-print Network

Native Plant Master Program Announces 2012 Classes The Native Plant Master® Program has announced by taking an award-winning Native Plant Master course. Sample one of the exciting classes taught by CSU faculty and other experts. Topics include basic botany, native plant landscaping, invasive weeds, native

359

Biotic resistance to plant invasions? Native herbivores prefer non-native plants  

Microsoft Academic Search

In contrast to expectations of the enemy release hypothesis, but consistent with the notion of biotic resistance, we found that native generalist crayfishes preferred exotic over native freshwater plants by a 3 : 1 ratio when plants were paired by taxonomic relatedness. Native crayfishes also preferred exotic over native plants when tested across 57 native and 15 exotic plants found

John D. Parker; Mark E. Hay

2005-01-01

360

Detection of iron-containing proteins contributing to the cellular labile iron pool by a native electrophoresis metal blotting technique  

Microsoft Academic Search

The labile iron pool (LIP) plays a role in generation of free radicals and is thus the target of chelators used for the treatment of iron overload. We have previously shown that the LIP is bound mostly to high molecular weight carriers (MW>5000). However, the iron does not remain associated with these proteins during native gel electrophoresis. In this study

Ji??? Petrák; Daniel Vyoral

2001-01-01

361

Impact of reaction conditions on architecture and rheological properties of starch graft polyacrylamide polymers  

Technology Transfer Automated Retrieval System (TEKTRAN)

We carried out experiments examining the impact that solvent selection and reaction conditions have on the radical initiated graft polymerization reaction of acrylamide onto starch. We have also evaluated the rheological properties the starch graftpolyacrylamide product when a gel is formed in water...

362

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.

363

North American Native Fishes Association  

NSDL National Science Digital Library

The North American Native Fishes Association (NANFA) works "to increase and disseminate knowledge about North America's native fishes and their habitats among aquarium hobbyists, biologists, fish and wildlife officials, anglers, educators, students, and others, through publications, electronic media, regional and national meetings, and other means." The NANFA website features a Checklist of Freshwater Fishes Native to North America and a Fish in Focus section with beautiful images and brief descriptions of such fish as the Hogchoker (Trinectes maculatus), Central Stoneroller (Campostoma anomalum), and Southern Redbelly Dace (Phoxinus erythrogaster). The site also contains information about an award program for breeders, grant programs, annual meetings, membership, and the NANFA quarterly magazine, _American Currents_. NANFA offers a solid collection of related links, and an electronic mailing list as well. The website is under construction and promises future sections relating to natural history, captive care, conservation, and collecting.

364

Polyacrylamide effect on hydraulic conductivity of hardsetting soils in Northeast of Brazil  

NASA Astrophysics Data System (ADS)

Among soil hydro-physical properties, hydraulic conductivity is more sensitive to changes in soil structure. Hydraulic conductivity describes the ease with which a fluid (usually water) can move through pore spaces or fractures. It depends on the intrinsic permeability of the material and on the degree of saturation, and on the density and viscosity of the fluid. Hardsetting soils present very low hydraulic conductivity values. When dry, these soils show high penetration resistance and consistency extremely hard, but change to friable when moist. In this condition are poorly structured, slaking when moist, limit agricultural machinery use and it may reduce the growth of the root system. In Brazil, these soils occur throughout of coastal zone in flat areas called "coastal tableland". Chemical ameliorant, such as polymers based on anionic polyacrylamide (PAM), improve hydraulic conductivity of soil in hardsetting soils. The primary functions of polyacrylamide soil conditioners are to increase soil tilth, aeration, and porosity and reduce compaction and water run-off. PAM effect is attributed to its ability to expand when placed in water, storing it in soil pore space, releasing it gradually to the plants. This process occurs by reducing the water flow through the pores of the soil, due to water molecules can be absorbed by PAM, providing water gradually. Thus, this study tested the hypothesis that PAM reduces the soil hardsetting character. The area is located in coastal zone in Goiana city, Pernambuco, northeastern of Brazil. This soil is typical hardsetting soil. Intact soil cores were collected from four horizons until 70cm depth. In the laboratory, the soil cores were saturated with different PAM concentrations (0.01, 0.005, 0.00125%) and H2O (control). Saturated hydraulic conductivity (Ksat) was determined using a constant head method, according to Klute and Dirksen (1986). Four replicates were used for each horizon and Tukey test at 5% probability was used by Assistat 7.6 beta. The sandy horizon had higher hydraulic conductivity in natural conditions, and the PAM, especially the concentration of 0.010%, reduced Ksat. This result confirms the action agglutinant of PAM organizing sand particles on aggregates, providing higher water retention, reducing water drainage and also Ksat values. In the other, especially in hardsetting horizon, when the lowest concentration (0.00125%) was applied reduced the effect of cohesion realized by increasing Ksat value. In conclude, PAM in hardsetting soils improve its physico-water proprieties when low concentrations.

Silva, Laércio; Almeida, Brivaldo; Melo, Diego; Marques, Karina; Almeida, Ceres

2013-04-01

365

Valuable Plants Native to Texas.  

E-print Network

-leafed grass. It will anyone to procure and grow the species of blue-eyed grass native -, ,lis locality and to bring in others as he may procure them. beaut It is Esch nvate - . --- bamb each like 1;1.7 m LILY P as A1 der c They Thalia dealbata... Roscoe. (T. bnrbata Small.) Powflery Thalia. A most iful but almost unknown plant as its native home is in deep swamps. found in sections 4B, 1, and 2. The plants consist of several leaves. leaf consists of a green stem about twenty inches long which...

Parks, Harris Braley

1937-01-01

366

Adhesive, elastomeric gel impregnating composition  

DOEpatents

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

Shaw, David Glenn (Tucson, AZ); Pollard, John Randolph (Tucson, AZ); Brooks, Robert Aubrey (Tijeras, NM)

2002-01-01

367

The effects of scaffold architecture and fibrin gel addition on tendon cell phenotype.  

PubMed

Development of tissue engineering scaffolds relies on careful selection of pore architecture and chemistry of the cellular environment. Repair of skeletal soft tissue, such as tendon, is particularly challenging, since these tissues have a relatively poor healing response. When removed from their native environment, tendon cells (tenocytes) lose their characteristic morphology and the expression of phenotypic markers. To stimulate tendon cells to recreate a healthy extracellular matrix, both architectural cues and fibrin gels have been used in the past, however, their relative effects have not been studied systematically. Within this study, a combination of collagen scaffold architecture, axial and isotropic, and fibrin gel addition was assessed, using ovine tendon-derived cells to determine the optimal strategy for controlling the proliferation and protein expression. Scaffold architecture and fibrin gel addition influenced tendon cell behavior independently in vitro. Addition of fibrin gel within a scaffold doubled cell number and increased matrix production for all architectures studied. However, scaffold architecture dictated the type of matrix produced by cells, regardless of fibrin addition. Axial scaffolds, mimicking native tendon, promoted a mature matrix, with increased tenomodulin, a marker for mature tendon cells, and decreased scleraxis, an early transcription factor for connective tissue. This study demonstrated that both architectural cues and fibrin gel addition alter cell behavior and that the combination of these signals could improve clinical performance of current tissue engineering constructs. PMID:25578703

Pawelec, K M; Wardale, R J; Best, S M; Cameron, R E

2015-01-01

368

Functional Annotation of 2D Protein Maps: The GelMap Portal  

PubMed Central

In classical proteome analyses, final experimental data are (a) images of 2D protein separations obtained by gel electrophoresis and (b) corresponding lists of proteins which were identified by mass spectrometry (MS). For data annotation, software tools were developed which allow the linking of protein identity data directly to 2D gels (“clickable gels”). GelMap is a new online software tool to annotate 2D protein maps. It allows (i) functional annotation of all identified proteins according to biological categories defined by the user, e.g., subcellular localization, metabolic pathway, or assignment to a protein complex and (ii) annotation of several proteins per analyzed protein “spot” according to MS primary data. Options to differentially display proteins of functional categories offer new opportunities for data evaluation. For instance, if used for the annotation of 2D Blue native/SDS gels, GelMap allows the identification of protein complexes of low abundance. A web portal has been established for presentation and evaluation of protein identity data related to 2D gels and is freely accessible at http://www.gelmap.de/. PMID:22639671

Senkler, Michael; Braun, Hans-Peter

2012-01-01

369

Differentiation between fresh and frozen-thawed sea bass (Dicentrarchus labrax) fillets using two-dimensional gel electrophoresis.  

PubMed

This study aimed to identify a protein marker that can differentiate between fresh skinless and frozen-thawed sea bass (Dicentrarchus labrax) fillets using the two-dimensional polyacrylamide gel electrophoresis (2-DE) technique. Distinct gel patterns, due to proteins with low molecular weight and low isoelectric points, distinguished fresh fillets from frozen-thawed ones. Frozen-thawed fillets showed two specific protein spots as early as the first day of the study. However, these spots were not observed in fresh fillets until at least 13days of storage between 0 and 4°C, fillets were judged, beyond this period, fish were unfit for human consumption as revealed by complementary studies on fish spoilage indicators namely total volatile basic nitrogen and biogenic amines. Mass spectrometry identified the specific proteins as parvalbumin isoforms. Parvalbumins may thus be useful markers of differentiation between fresh and frozen-thawed sea bass fillets. PMID:25624236

Ethuin, Pierrette; Marlard, Sylvain; Delosière, Mylène; Carapito, Christine; Delalande, François; Van Dorsselaer, Alain; Dehaut, Alexandre; Lencel, Valérie; Duflos, Guillaume; Grard, Thierry

2015-06-01

370

Determination of dosimetric perturbations caused by aneurysm clip in stereotactic radiosurgery using gel phantoms and EBT-Gafchromic films  

SciTech Connect

Some radiotherapy patients are treated with titanium surgical aneurysm clips in the radiation field. This is of particular importance for stereotactic radiosurgery brain treatments, where the length of the blade of the clip may be comparable to the size of the radiation field. This study seeks to determine the extent of the dosimetric effects caused by surgical clips in stereotactic radiosurgery, using polyacrylamide gel phantoms and EBT type Gafchromic films. Using gel phantoms scanned with magnetic resonance imaging scanner, dose enhancement of around 20% was noted at distances less than 2 mm away from the clip surface. Gafchromic films showed about 6% variations in the dose up to few millimeters from the clip. These experimental results confirmed results predicted by Monte Carlo simulation techniques for higher density material surgical clips such as lead and platinum. Moreover, these experimental measurements clearly indicate dose reduction due to radiation attenuation behind the clip of about 4%.

Geso, M.; Ackerly, T.; Brown, S.; Chua, Z.; He, C.; Wong, C. J.; Powell, C. E.; Ho, A.; Qiao, G.; Solomon, D. H.; Patterson, W.; Droege, J. M. [School of Medical Sciences, RMIT University, Bundoora, Victoria 3083 (Australia); Department of Chemical and Biomolecular Engineering, University of Melbourne, Parkville, Victoria 3010 (Australia); Radiation Oncology Victoria, East Melbourne, Victoria 3002 (Australia); William Buckland Radiotherapy Centre, Alfred Hospital, Melbourne, Victoria 3004 (Australia)

2008-02-15

371

Purification and characterization of chlorophyllase from alga Phaeodactylum tricornutum by preparative native electrophoresis  

Microsoft Academic Search

The partially purified chlorophyllase, obtained from the algaPhaeodactylum tricornutum, was further purified by preparative native gel electrophoresis. The purification procedure provided the recovery of large\\u000a amounts of a single purified chlorophyllase fraction. However, the electrophoretic analyses of the purified enzymatic fraction\\u000a under denaturing conditions demonstrated the presence of two bands with mol wt of 43 ±3 and 46 ±3 kDa.

A. Khalyfa; S. Kermasha; P. Marsot; M. Goetghebeur

1995-01-01

372

Self-assembled reduced graphene oxide/polyacrylamide conductive composite films.  

PubMed

Substrate supported conductive thin films are prepared by the self-assembly of graphene oxide (GO) on a cationic polyacrylamide (CPAM) layer followed by a subsequent chemical reduction. During self-assembly, the dispersed GO nanosheets with a negative zeta potential from solution are spontaneously assembled onto the positively charged CPAM adsorption layer. In addition, CPAM adsorption on the substrate is studied with an electrochemical quartz crystal microbalance (EQCM), showing adsorption stabilization could be established in less than 150 s. The electrostatic interactions between GO and CPAM are investigated by changing the polarization potential with EQCM for the first time, and optimal conditions for facilitating self-assembly are determined. The self-assembled GO/CPAM films are further characterized by Raman spectroscopy, infrared spectroscopy and atomic force microscopy. Importantly, reduced GO (R-GO)/CPAM composite films exhibiting a sheet resistance of 3.1 k?/sq can be obtained via in situ reduction in sodium borohydride for 20 min at room temperature. This provides a simple, highly effective, and green route to prepare conductive graphene-based composite thin films. PMID:25329422

Yu, Shiyou; Li, Ning; Higgins, Drew; Li, Deyu; Li, Qing; Xu, Hui; Spendelow, Jacob S; Wu, Gang

2014-11-26

373

Polyacrylamide application versus forest residue mulching for reducing post-fire runoff and soil erosion.  

PubMed

For several years now, forest fires have been known to increase overland flow and soil erosion. However, mitigation of these effects has been little studied, especially outside the USA. This study aimed to quantify the effectiveness of two so-called emergency treatments to reduce post-fire runoff and soil losses at the microplot scale in a eucalyptus plantation in north-central Portugal. The treatments involved the application of chopped eucalyptus bark mulch at a rate of 10-12 Mg ha(-1), and surface application of a dry, granular, anionic polyacrylamide (PAM) at a rate of 50 kg ha(-1). During the first year after a wildfire in 2010, 1419 mm of rainfall produced, on average, 785 mm of overland flow in the untreated plots and 8.4 Mg ha(-1) of soil losses. Mulching reduced these two figures significantly, by an average 52 and 93%, respectively. In contrast, the PAM-treated plots did not differ from the control plots, despite slightly lower runoff but higher soil erosion figures. When compared to the control plots, mean key factors for runoff and soil erosion were different in the case of the mulched but not the PAM plots. Notably, the plots on the lower half of the slope registered bigger runoff and erosion figures than those on the upper half of the slope. This could be explained by differences in fire intensity and, ultimately, in pre-fire standing biomass. PMID:24055663

Prats, Sergio Alegre; Martins, Martinho António Dos Santos; Malvar, Maruxa Cortizo; Ben-Hur, Meni; Keizer, Jan Jacob

2014-01-15

374

One step synthesis of polyacrylamide functionalized graphene and its application in Pb(II) removal  

NASA Astrophysics Data System (ADS)

Polyacrylamide grafted graphene (PAM-g-graphene) from graphite oxide (GO) was successfully prepared by ?-ray irradiation with acrylamide monomers in aqueous at room temperature in this paper. Our strategy involves the PAM chains graft on the surface and between the layers of GO by in situ radical polymerization which led to the exfoliation of GO into individual sheets. Results show that the degree of grafting of PAM-g-graphene samples is 24.2%, and the thickness is measured to be 2.59 nm. Moreover, the as-prepared PAM-g-graphene with some amino from PAM and little oxygen functional groups exhibit superior adsorption of Pb(II) ions. The adsorption processes reach equilibrium in just 30 min and the adsorption isotherms are described well by Langmuir and Freundlich classical isotherms models. The determined adsorption capacity of PAM-g-graphene is 819.67 mg g-1 (pH 6) for Pb(II), which is 20 times and 8 times capacities of that for graphene nanosheets and carbon nanotubes according to reports, respectively. This chemically modified graphene synthesized by this fast one-step approach, featuring a good versatility and adaptability, excellent adsorption capacity and rapid extraction, may provide a new idea for the global problem of heavy metal pollutants' removal in water.

Xu, Zhiwei; Zhang, Yaoyao; Qian, Xiaoming; Shi, Jie; Chen, Lei; Li, Baodong; Niu, Jiarong; Liu, Liangsen

2014-10-01

375

Arsenic remediation from drinking water by synthesized nano-alumina dispersed in chitosan-grafted polyacrylamide.  

PubMed

An arsenic adsorbent comprising alumina nanoparticles dispersed in polymer matrix was developed and its removal potential studied. Alumina nanoparticles were prepared by reverse microemulsion technique and these were immobilized on chitosan grafted polyacrylamide matrix by in situ dispersion. The loading capacity of this new synthesized adsorbent was found to be high (6.56 mg/g). Batch adsorption studies were performed as a function of contact time, initial arsenic concentration, pH and presence of competing anions. The removal was found to be pH dependent, and maximum removal was obtained at pH 7.2 while the equilibrium time was 6h. The equilibrium adsorption data fitted very well with Freundlich isotherm. However, the D-R isotherm studies indicated that chemisorptions might play an important role. This was also confirmed by the FTIR study of the arsenic loaded adsorbent. A mechanism of arsenic sorption by the new polymeric adsorbent has been proposed. The regeneration study of the adsorbent resulted in retention of 94% capacity in the fifth cycle. An optimum pH of 7.2, operation at normal temperature, high adsorption capacity and good recycle potential of this new adsorbent would make it an ideal material for removal of arsenic from drinking water. PMID:22647233

Saha, Suparna; Sarkar, Priyabrata

2012-08-15

376

Cationic polyacrylamide as coagulant aid with titanium tetrachloride for low molecule organic matter removal.  

PubMed

This is the first attempt to use cationic polyacrylamide (PAM) as coagulant aid with titanium tetrachloride (TiCl4) to improve the coagulation performance and floc properties. Coagulation-flocculation treatment was applied to simulated water (with fulvic acid (FA) as model organic matter) for both coagulation behavior investigation and floc characterization. The effect of PAM on floc reformation properties after cyclic breakage/regrowth was also investigated. Ultrafiltration experiments were performed to investigate the influence of PAM aided TiCl4 coagulation on the membrane fouling. The results showed that organic removal was enhanced by PAM addition at low TiCl4 doses. Floc growth rate and floc size were significantly affected by dosing sequence. TiCl4-PAM significantly improved the floc strength factors (Sf) and recovery factors (Rf). The dosing sequence of TiCl4 and PAM significantly influenced the floc structure. Characterization of the flocculated sludge indicated that TiO2 with anatase structure and high photocatalytic activity could be obtained from the TiCl4-PAM flocculated sludge. PMID:23708450

Zhao, Y X; Gao, B Y; Qi, Q B; Wang, Y; Phuntsho, S; Kim, J-H; Yue, Q Y; Li, Q; Shon, H K

2013-08-15

377

Bioelectricity-assisted partial degradation of linear polyacrylamide in a bioelectrochemical system.  

PubMed

The wide application of water-soluble linear polyacrylamides (PAMs) can cause serious environmental pollution. Biological treatment of PAMs receives very limited efficiency due to their recalcitrance to the microbial degradation. Here, we show the bioelectrochemical system (BES) can be used as an effective strategy to improve the biodegradation efficiency of PAMs. A linear PAM with viscosity-average molecular weight of 5?×?10(6) was treated in the anodic chamber of BES reactor, and the change of PAM structure during the degradation process was investigated. The anodic bacteria in the BES demonstrated abilities to utilize the PAM as the sole carbon and nitrogen source to generate electricity. Both the anode-attached and planktonic bacteria contributed to the electricity generation, while the anode-attached community exhibited stronger electron transfer ability than the planktonic one. The closed-circuit and open-circuit operations of the BES reactor obtained chemical oxygen demand (COD) removal efficiencies of 32.5 and 7.4 %, respectively, implying the generation of bioelectricity could enhance the biodegradation of PAM. Structure analysis suggested the carbon chain of PAM was partially degraded in the BES, producing polymeric products with lower molecular weight. The microbial cleavage of the carbon chain was proposed to start from the "head-to-head" linkages and end with the formation of ether bonds. PMID:25193420

Cui, Yu-Zhi; Zhang, Jian; Sun, Min; Zhai, Lin-Feng

2015-01-01

378

Reducing sediment and phosphorus in tributary waters with alum and polyacrylamide.  

PubMed

The Salton Sea is the largest inland water body in California, covering an area of 980 km(2). Inflow to the Salton Sea (1.6 km(3) yr(-1)) is predominately nutrient-rich agricultural wastewater, which has led to eutrophication. Because internal phosphorus release from the bottom sediments is comparatively low and external phosphorus loading to the Salton Sea is high, reduction of tributary phosphorus is expected to reduce algal blooms, increase dissolved oxygen, and reduce odors. Removing both dissolved phosphorus and phosphorus-laden sediment from agricultural drainage water (ADW) should decrease eutrophication. Both alum and polyacrylamide (PAM) are commonly used in wastewater treatment to remove phosphorus and sediment and were tested for use in tributary waters. Laboratory jar tests determined PAM effectiveness (2 mg L(-1)) for turbidity reduction as cationic > anionic = nonionic. Although cationic PAM was the most effective at reducing turbidity at higher speeds, there was no observed difference between the neutral and anionic PAMs at velocity gradients of 18 to 45 s(-1). Alum (4 mg L(-1) Al) reduced turbidity in low energy systems (velocity gradients < 10 s(-1)) by 95% and was necessary to reduce soluble phosphorus, which comprises 47 to 100% of the total P concentration in the tributaries. When PAM was added with alum, the anionic PAM became ineffective in aiding flocculation. The nonionic PAM (2 mg L(-1)) + alum (4 mg L(-1) Al) is recommended to reduce suspended solids in higher energy systems and reduce soluble P by 93%. PMID:16221819

Mason, L B; Amrhein, C; Goodson, C C; Matsumoto, M R; Anderson, M A

2005-01-01

379

Multiregion shear thinning for subsequent static self-thickening in chitosan-graft-polyacrylamide aqueous solution.  

PubMed

A special shear thinning phenomenon followed by static self-thickening in chitosan-graft-polyacrylamide (GPAM) aqueous solutions was investigated. This multiregion shear thinning can be defined as the first stage of the recently reported shear induced self-thickening (SIT) in our previous work. The three thinning regions (labeled as N1, N2, and N3) are considered very important, and they can reflex the complex variations of intermolecular interactions among and inside the aggregates in solution with increasing shear rate. To verify this multiregion shear thinning, a critical concentration of GPAM for this three-region shear thinning was first investigated. Shear recovery tests with the maximal shear rates located in the N1-N3 were carried out to ascertain the crucial role of shear thinning in SIT. The mechanisms of these three shear thinning regions were proposed based on the dependence of shear rheological behavior on various conditions in each region, including GPAM concentration, grafting ratio, temperature, added hydrogen bonding breaker, and salt. The above results confirm that N1 is due to the breakage of the interactions among hydrogen bonding aggregates, while N2 and N3 are attributed to the progressive destruction of the aggregates. As the first stage of SIT, shear thinning can markedly break the original aggregate and expose additional hydrogen bonding stickers to reform more aggregates with bigger size, resulting in the final higher viscosity. PMID:24236534

Jin, Lei; Tan, Yeqiang; Shangguan, Yonggang; Lin, Yu; Xu, Bo; Wu, Qiang; Zheng, Qiang

2013-12-01

380

Granular and Dissolved Polyacrylamide Effects on Erosion and Runoff under Simulated Rainfall.  

PubMed

Polyacrylamide (PAM) has been demonstrated to reduce erosion under many conditions, but less is known about the effects of its application method on erosion and concentrations in the runoff water. A rainfall simulation study was conducted to evaluate the performance of an excelsior erosion control blanket (cover) and two PAM application methods. The treatments were (i) no cover + no PAM (control), (ii) cover + no PAM, (iii) cover + granular PAM (GPAM), and (iv) cover + dissolved PAM (DPAM) applied to soil packed in wooden runoff boxes. The GPAM or DPAM (500 mg L) was surface-applied at a rate of 30 kg ha 1 d before rainfall simulation. Rainfall was applied at 83 mm h for 50 min and then repeated for another 20 min after a 30-min rest period. Runoff samples were analyzed for volume, turbidity in nephelometric turbidity units (NTU), total suspended solids (TSS), sediment particle size distribution, and PAM concentration. The cover alone reduced turbidity and TSS in runoff by >60% compared with the control (2315 NTU, 2777 mg TSS L). The PAM further reduced turbidity and TSS by >30% regardless of the application method. The median particle diameter of eroded sediments for PAM treatments was seven to nine times that of the control (12.4 ?m). Loss of applied PAM in the runoff water (not sediment) was 19% for the GPAM treatment but only 2% for the DPAM treatment. Both GPAM and DPAM were effective at improving groundcover performance, but DPAM resulted in much less PAM loss. PMID:25602214

Kang, Jihoon; Amoozegar, Aziz; Heitman, Joshua L; McLaughlin, Richard A

2014-11-01

381

Polyacrylamide-clinoptilolite/Y-zeolite composites: characterization and adsorptive features for terbium.  

PubMed

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, (160)Tb was the radiotracer. The composites were the hybrid formations of PAAm and Z or YZ. Tb adsorption capacities of the composites were higher than those of bare Z and YZ. The compatibility of Tb adsorption kinetics to the second order and Weber-Morris models implied that the sorption process was chemical via ion exchange. The values of enthalpy and entropy changes were positive and the negative free enthalpy change was evidence for the spontaneity of adsorption. The reusability tests for the composites for five uses demonstrated that the adsorbents could be reused after complete recovery of the loaded ion. Unlike PAAm-YZ, PAAm-Z was resistant to acidic environment. The overall results eventually suggested that the composite of Z and PAAm was a potential cost effective adsorbent for Tb(3+) and REs. PMID:21256673

Bayba?, Demet; Ulusoy, Ulvi

2011-03-15

382

Effect of heparin calcium different concentrations on some physical properties and structure in polyacrylamide matrix  

NASA Astrophysics Data System (ADS)

Films of polyacrylamide (PAAm) doped with different concentrations of heparin calcium, from 0.0 to 8 wt%, have been prepared by casting method. Studies were carried out utilizing X-ray, FT-IR, UV/VIS, DSC and DC electrical conduction to characterize the structural, optical and thermal properties of the films. Results revealed that the structural and chemical characterizations of PAAm films are affected by the addition of heparin calcium content. XRD spectra revealed that the amorphous phases increase with increase in filling levels of heparin (FLs). FT-IR analysis revealed that incorporation of heparin calcium leads to a small modification in the spectra of films. The optical absorption spectra in the UV/VIS region revealed structural variation increases with increase in concentration, which is reflected in the form of decrease in the energy band gap Eg. Significant changes of DSC curves of the films suggest that strong interaction established between heparin calcium and PAAm molecules. The DC electric conduction data were interpreted on the basis of an intrachain one-dimensional interpolaron hopping model of Kuivalainen.

Abdelrazek, E. M.; Ibrahim, Hosam S.

2010-10-01

383

Water Soluble Usnic Acid-Polyacrylamide Complexes with Enhanced Antimicrobial Activity against Staphylococcus epidermidis  

PubMed Central

Usnic acid, a potent antimicrobial and anticancer agent, poorly soluble in water, was complexed to novel antimicrobial polyacrylamides by establishment of strong acidic-base interactions. Thermal and spectroscopic analysis evidenced a molecular dispersion of the drug in the polymers and a complete drug/polymer miscibility for all the tested compositions. The polymer/drug complexes promptly dissolved in water and possessed a greater antimicrobial activity against Staphylococcus epidermidis than both the free drug and the polymer alone. The best results were obtained with the complex based on the lowest molecular weight polymer and containing a low drug content. Such a complex showed a larger inhibition zone of bacterial growth and a lower minimum inhibitory concentration (MIC) with respect to usnic acid alone. This improved killing effect is presumably due to the reduced size of the complexes that allows an efficient cellular uptake of the antimicrobial complexes. The killing effect extent seems to be not significantly dependent on usnic acid content in the samples. PMID:23549269

Francolini, Iolanda; Taresco, Vincenzo; Crisante, Fernanda; Martinelli, Andrea; D’Ilario, Lucio; Piozzi, Antonella

2013-01-01

384

Flexible polyacrylamide substrata for the analysis of mechanical interactions at cell-substratum adhesions  

NASA Technical Reports Server (NTRS)

We have described a powerful tool for the study of mechanical interactions between cells and their physical environment. Although the approach has already been used in a variety of ways to measure traction forces and to characterize active and passive responses of cultured cells to mechanical stimulation, it can be extended easily and combined with other microscopic approaches, including fluorescent analog imaging (Beningo et al., 2001), photobleaching, calcium imaging, micromanipulation, and electrophysiology. This method will be particularly useful for studying the functions of various components at focal adhesions, and the effects of mechanical forces on focal adhesion-mediated signal transduction. In addition, the method can be extended to a 3D setting, e.g., by sandwiching cultured cells between two layers of polyacrylamide to create an environment mimicking that in the tissue of a multicellular organism. Whereas chemical interactions between cells and the environment have been investigated extensively, many important questions remain as to the role of physical forces in cellular functions and the interplay between chemical and physical mechanisms of communication. The present approach, as well as other approaches capable of probing physical interactions, should fill in this important gap in the near future.

Beningo, Karen A.; Lo, Chun-Min; Wang, Yu-Li

2002-01-01

385

Acrylamide release resulting from sunlight irradiation of aqueous polyacrylamide/iron mixtures.  

PubMed

Linear anionic polyacrylamide (PAM) has been used in irrigation practices as a flocculating agent to minimize water losses through seepage in earthen canals. The stability of PAM is of concern because of the possibility of acrylamide (AMD) monomer release during environmental weathering. Aqueous solutions of commercial PAM mixed with ferric sulfate, subjected to simulated and natural sunlight irradiation, showed polymer chain scission and release of the AMD monomer. At acid/neutral pH, the amount of AMD released was directly related to the concentration of ferric ion and the irradiation time. At alkaline pH (approximately 8), PAM/Fe(3+) mixtures were stable under irradiation. PAM chain scission involved the hydroxyl radical, but specific AMD release appeared to require PAM-bound iron. Low iron concentrations and alkaline pH of irrigation water would limit AMD release. Residual monomer in PAM can contribute AMD to irrigation water, but concentrations would remain below the U.S. EPA drinking water standard of 0.5 ppb. PMID:18351736

Woodrow, James E; Seiber, James N; Miller, Glenn C

2008-04-23

386

Enhanced dewaterability of waste-activated sludge by combined cationic polyacrylamide and magnetic field pretreatment.  

PubMed

The potential function of combining magnetic field (MF) pretreatment with cationic polyacrylamide (CPAM) additive on enhancing the dewaterability of waste-activated sludge was investigated in the present work. Two reactors were involved in a specially designed experimental apparatus, one of which was built with MF accessories. Several parameters were conducted, including CPAM dosages, MF strengths and processing times, respectively. Capillary suction time (CST) and specific resistance to filtration (SRF) were used to evaluate sludge dewaterability. Extracellular polymeric substances (EPS) concentration was also determined in an attempt to identify the observed changes in dewaterability. It was indicated by the results that both CPAM conditioning and MF pretreatment on sludge can lower CST and SRF values. However, subjecting to a combination of MF pretreatment and CPAM conditioning, sludge dewaterability was significantly enhanced beyond the level observed of CPAM addition alone. The lowest CST and SRF values of 36.5?s and 0.75?×?10(12)?m?kg(-1), respectively, were obtained when sludge was co-conditioned by CPAM (at a dosage of 40?mg?L(-1)) and MF (at an induction of 40?mT) for 30?min, suggesting the optimal condition for enhancing sludge dewaterability. It is also shown from the significant correlations between EPS, protein, polysaccharide and CST/SRF that the increment of EPS concentration in sludge supernatant may be the major reason for the enhancement of dewaterability. PMID:25518985

Bi, Dongsu; Guo, Xiaopin; Cai, Zhihong; Yu, Zhen; Wang, Dingmei; Wang, Yueqiang

2015-02-01

387

Hydrolyzed polyacrylamide grafted maize starch based microbeads: application in pH responsive drug delivery.  

PubMed

The present study details the synthesis, characterization and pharmaceutical application of hydrolysed polyacrylamide grafted maize starch (HPam-g-MS) as promising polymeric material for the development of pH responsive microbeads. Different grades of graft copolymer were synthesized by changing the net microwave irradiation time, while keeping all other factors constant. Acute oral toxicity study performed in rodents ensured the bio-safety of graft copolymer for clinical application. Various batches of aceclofenac loaded microbeads were prepared by ionic gelation method using synthesized graft copolymers and evaluated for formulation parameters. FTIR spectroscopy confirmed the chemical compatibility between drug and graft copolymer. Results of in vitro release study (USP type-II) carried out in two different pH media (pH 1.2 acid buffer and pH 7.4 phosphate buffer) showed that release rate of drug from developed microbeads was a function of both: (a) surrounding pH and (b) the matrix composition. The drug release was relatively higher at alkaline pH as compared to acidic pH and this feature is desirable from viewpoint of site specific drug delivery. A direct correlation was observed between percentage grafting and microbeads performance and it presents a scope for further research on application and optimization of HPam-g-MS based microbeads as drug delivery carriers. PMID:24971555

Setty, C Mallikarjuna; Deshmukh, Anand S; Badiger, Aravind M

2014-09-01

388

Effect of cationic polyacrylamide adsorption kinetics and ionic strength on precipitated calcium carbonate flocculation.  

PubMed

The effect of polymer adsorption kinetics and ionic strength on the dynamics of particle flocculation was quantified using a model system consisting of precipitated calcium carbonate (PCC) and cationic polyacrylamide (CPAM) at a low shear rate. All early flocculations detectable by a photodispersion analyzer (PDA) happened in nonequilibrium polymer adsorption regimes. We observed discrepancies in flocculation rates with the surface coverage theory, which is based on a simple monolayer adsorption model, in both early and late flocculation stages. For instance, the same amount of adsorbed CPAM reached at different polymer doses demonstrated different flocculating capabilities. This highlighted the importance of polymer adsorption kinetics upon flocculation. The transient conformation of the adsorbed CPAM during the kinetic process sometimes even superceded the adsorbed amount in the determination of PCC flocculation. Both antagonistic and synergetic effects of increased ionic strength on the CPAM-induced PCC aggregation were observed during early flocculation. However, late-stage PCC flocculation shared some similarities, irrespective of polymer dose and ionic strength. Despite the decreased amount of adsorbed polymer from the increased ionic strength, the combination of CPAM and salt, at certain concentrations, demonstrated a synergy to promote PCC aggregation more efficiently than the same amount of the respective components. PMID:20929196

Peng, Ping; Garnier, Gil

2010-11-16

389

DNA gel particles: an overview.  

PubMed

A general understanding of interactions between DNA and oppositely charged compounds forms the basis for developing novel DNA-based materials, including gel particles. The association strength, which is altered by varying the chemical structure of the cationic cosolute, determines the spatial homogeneity of the gelation process, creating DNA reservoir devices and DNA matrix devices that can be designed to release either single- (ssDNA) or double-stranded (dsDNA) DNA. This review covers recent developments on the topic of DNA gel particles formed in water-water emulsion-type interfaces. The degree of DNA entrapment, particle morphology, swelling/dissolution behavior and DNA release responses are discussed as functions of the nature of the cationic agent used. On the basis of designing DNA gel particles for therapeutic purposes, recent studies on the determination of the surface hydrophobicity and the hemolytic and the cytotoxic assessments of the obtained DNA gel particles have been also reported. PMID:24119768

Morán, M Carmen; Vinardell, M Pilar; Infante, M Rosa; Miguel, M Graça; Lindman, Björn

2014-03-01

390

Creating Wildlife Habitat with Native Florida Freshwater Wetland Plants1  

E-print Network

many more species than non-native plants because native wildlife evolved with native plant communities, they are typically easier to maintain than non-native species. And most native wetland plants require little native plants typically fare better than introduced species, some non-native plants have thrived

Watson, Craig A.

391

Phys. Med. Biol. 44 (1999) 18751884. Printed in the UK PII: S0031-9155(99)02424-0 Dynamics of polymerization in polyacrylamide gel (PAG)  

E-print Network

). ThedosimetersusedinthistypeofstudyhavegenerallybeenvariantsoftheoriginalBANG (bis-acrylamide, nitrogen, gelatin) PAG recipe (Maryanski et al 1994). This formulation, which we have also used, consists of 3% by weight of each of the co-monomers acrylamide and N,N -methylene-bis-acrylamide of acrylamide and MBA in solution is accepted to be a free radical process (Collinson et al 1957, Panajkar et al

Doran, Simon J.

392

Application of NMR spectroscopy and multidimensional imaging to the gelcasting process and in-situ real-time monitoring of cross-linking polyacrylamide gels  

SciTech Connect

In the gelcasting process, a slurry of ceramic powder in a solution of organic monomers is cast in a mold. The process is different from injection molding in that it separates mold-filling from setting during conversion of the ceramic slurry to a formed green part. In this work, NMR spectroscopy and imaging have been conducted for in-situ monitoring of the gelation process and for mapping the polymerization. {sup 1}H nuclear magnetic resonance spectra have been obtained during polymerization of a premix of soluble reactive methacrylamide (monomer) and N, N`-methylene bisacrylamide (cross-linking molecules). The premix was polymerized by adding ammonium persulfate (initiator) and tetramethyl-ethylene-diamine (accelerator) to form long-chain, cross-linked polymers. The time-varying spin-lattice relaxation times T{sub 1} during polymerization have been studied at 25 and 35{degrees}C, and the variation of spectra and T{sub 1} with respect to extent of polymerization has been determined. To verify homogeneous polymerization, multidimensional NMR imaging was utilized for in-situ monitoring of the process. The intensities from the images are modeled and the correspondence shows a direct extraction of T{sub 1} data from the images.

Ahuja, S.; Dieckman, S.L.; Gopalsami, N. [and others

1995-04-01

393

Optimized method for rapid protein electroblotting Protein electroblotting is a common method for transferring proteins out of a polyacrylamide gel onto  

E-print Network

tank or by placing the whole apparatus in a cold room to offset the heat that is generated. Tank tank method HeLa lysate (~3.0 mg/mL) prepared by nitrogen cavitation was serially diluted 1:2, prepared

Cai, Long

394

A Mandate for Native History  

ERIC Educational Resources Information Center

The Montana Indian Education For All Act may be setting an audacious national precedent for America's primary and secondary schools. The law requires all Montana schools to include curricula about the history, culture and contemporary status of the state's American Indian population. The new constitutional mandate has eyes throughout Native…

Pember, Mary Annette

2007-01-01

395

Roadside revegetation by native plants  

Microsoft Academic Search

Recognizing the severity of road effects and need for developing a natural and self-sustained roadside vegetation cover, this study aimed to provide an ecological basis for selecting desirable native plants based on their autecological attributes by floristic analysis of naturally colonized plants in roadside microhabitats. We hypothesized that (i) vegetation zonation along roadsides is a function of the different microtopography

M. N. Karim; Azim U. Mallik

2008-01-01

396

Native Americans in Public Health.  

ERIC Educational Resources Information Center

The Family Spirit Project provides health and parenting education and in-home support to Navajo and Apache teen parents. The public-health careers of Native professionals allied with the project are described, including a public health administrator, a trainer of field workers, and a medical researcher specializing in communicable diseases that…

Westberg, Jane

2003-01-01

397

Studies in Native American Languages.  

ERIC Educational Resources Information Center

Eight original research papers on Native American languages by faculty and students of the Linguistics Department and other related departments of the University of Kansas are presented. The titles and authors include the following: "Comanche Consonant Mutation: Initial Association or Feature Spread?" (James L. Armagost); "The Alsea Noun Phrase"…

Ok, Jong-seok, Ed.; Taneri, Mubeccel, Ed.

1989-01-01

398

Native American Adult Reader I.  

ERIC Educational Resources Information Center

Aspects of Native American history and culture as well as issues and concerns of American Indians are presented in the twelve short articles in this reader for adults. Intended for use in an adult basic education/GED program, the reader features simply written stories (for grades 0-3), illustrations, vocabulary lists and student study questions.…

King, Lovern Root, Ed.

399

NATIVE TERRESTRIAL ANIMAL SPECIES RICHNESS  

EPA Science Inventory

These data represent predicted current distributions of all native mammals, birds, reptiles, amphibians and butterflies in the Middle-Atlantic region. The data are available for both 8-digit HUCs and EMAP hexagons and represent total species counts for each spatial unit....

400

Agarose Gel Electrophoresis of RNA  

Microsoft Academic Search

\\u000a Gel electrophoresis is one of the most important techniques currently available for the fractionation of RNA. The experimental\\u000a procedure is relatively simple, but nevertheless achieves very reproducible results and high resolution. RNA is a polyanion\\u000a and will therefore migrate toward the positive electrode in an electric field. If the migration occurs through a gel matrix\\u000a of carefully chosen pore size,

Robert J. Slater

401

TOPICAL REVIEW: Polymer gel dosimetry  

NASA Astrophysics Data System (ADS)

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.

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

Topical Review: Polymer gel dosimetry  

PubMed Central

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

2010-01-01

403

Biodegradation of polyacrylamide by anaerobic digestion under mesophilic condition and its performance in actual dewatered sludge system.  

PubMed

Polyacrylamide (PAM) used in sludge dewatering widely exists in high-solid anaerobic digestion. Degradation of polyacrylamide accompanied with accumulation of its toxic monomer is important to disposition of biogas residues. The potential of anaerobic digestion activity in microbial utilization of PAM was investigated in this study. The results indicated that the utilization rate of PAM (as nitrogen source) was influenced by accumulation of ammonia, while cumulative removal of amide group was accorded with zeroth order reaction in actual dewatered system. The adjoining amide group can combined into ether group after biodegradation. PAM can be broken down in different position of its carbon chain backbone. In actual sludge system, the hydrolytic PAM was liable to combined tyrosine-rich protein to form colloid complex, and then consumed as carbon source to form monomer when easily degradable organics were exhausted. The accumulation of acrylamide was leveled off ultimately, accompanied with the yield of methane. PMID:24345566

Dai, Xiaohu; Luo, Fan; Yi, Jing; He, Qunbiao; Dong, Bin

2014-02-01

404

Pre-Cast Gel Electrophoresis Guide  

E-print Network

Novex® Pre-Cast Gel Electrophoresis Guide Version B January 27, 2003 IM-1002 Novex® Pre-Cast Gel Electrophoresis Guide General information and protocols for using Novex® pre-cast gels www.invitrogen.com tech.....................................................................................................................1 Novex® Pre-Cast Gels

Kirschner, Marc W.

405

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

PubMed

Responsive biomaterial hydrogels attract significant attention due to their biocompatibility and degradability. In order to make chitosan based gels, we first graft one layer of chitosan to silica, and then build a chitosan/poly(acrylic acid) multilayer using the layer-by-layer approach. After cross-linking the chitosan present in the polyelectrolyte multilayer, poly(acrylic acid) is partly removed by exposing the multilayer structure to a concentrated carbonate buffer solution at a high pH, leaving a surface-grafted cross-linked gel. Chemical cross-linking enhances the gel stability against detachment and decomposition. The chemical reaction between gluteraldehyde, the cross-linking agent, and chitosan was followed in situ using total internal reflection Raman (TIRR) spectroscopy, which provided a molecular insight into the complex reaction mechanism, as well as the means to quantify the cross-linking density. The amount of poly(acrylic acid) trapped inside the surface grafted films was found to decrease with decreasing cross-linking density, as confirmed in situ using TIRR, and ex situ by Fourier transform infrared (FTIR) measurements on dried films. The responsiveness of the chitosan-based gels with respect to pH changes was probed by quartz crystal microbalance with dissipation (QCM-D) and TIRR. Highly cross-linked gels show a small and fully reversible behavior when the solution pH is switched between pH 2.7 and 5.7. In contrast, low cross-linked gels are more responsive to pH changes, but the response is fully reversible only after the first exposure to the acidic solution, once an internal restructuring of the gel has taken place. Two distinct pKa's for both chitosan and poly(acrylic acid), were determined for the cross-linked structure using TIRR. They are associated with populations of chargeable groups displaying either a bulk like dissociation behavior or forming ionic complexes inside the hydrogel film. PMID:25006685

Liu, Chao; Thormann, Esben; Claesson, Per M; Tyrode, Eric

2014-07-29

406

Preparation of polyacrylamide\\/CdS nanocomposites by a combination of reverse microemulsion and CO 2 antisolvent techniques  

Microsoft Academic Search

Polyacrylamide(PAM)\\/cadmium sulfide(CdS) nanocomposites have been successfully prepared by combination of reverse microemulsion and carbon dioxide antisolvent techniques. TEM, XRD, and FTIR were used to characterize the nanocomposites obtained. TEM photographs of the nanocomposites show that their diameter is approximately 30–60 nm. This method has potential advantages, for example the procedure is simple and the solutions can be easily reused.

Tiancheng Mu; Jimin Du; Zhonghao Li; Zhimin Liu; Buxing Han; Jiaqiu Wang; Donghai Sun; Bo Wang

2004-01-01

407

A Novel Ultraviolet Irradiation Technique for Fabrication of Polyacrylamide–metal (M = Au, Pd) Nanocomposites at Room Temperature  

Microsoft Academic Search

Polyacrylamide (PAM)–metal (M = gold, palladium) nanocomposites with metal nanoparticles homogeneously dispersed in the polymer matrix have been prepared via a novel ultraviolet irradiation technique at room temperature, which is based on the simultaneous occurrence of photo-reduction formation of the colloidal metal particles and photo-polymerization of the acrylamide (AM) monomer. The UV–vis absorption spectra and TEM were employed to characterize

Y. Zhou; L. Y. Hao; Y. R. Zhu; Y. Hu; Z. Y. Chen

2001-01-01

408

Evaluation of the flocculation performance of carboxymethyl chitosan- graft-polyacrylamide, a novel amphoteric chemically bonded composite flocculant  

Microsoft Academic Search

In the present work, a novel amphoteric chemically bonded composite flocculant (carboxymethyl chitosan-graft-polyacrylamide, denoted as CMC-g-PAM) was successfully prepared and used to flocculate the kaolin suspension. The flocculation performance of CMC-g-PAM in acidic, neutral, and alkaline conditions was systematically evaluated by light scattering in combination with fractal theory, as well as by traditional turbidity and zeta potential measurements. Based on

Zhen Yang; Bo Yuan; Xin Huang; Junyu Zhou; Jun Cai; Hu Yang; Aimin Li; Rongshi Cheng

409

Enhancement of the effect of coal fly ash by a polyacrylamide soil conditioner on growth of wheat  

Microsoft Academic Search

Wheat (Triticum aestivum L. cv. INIA66R) was grown in a calcareous clay soil, a Torrifluvents from Imperial Valley, California, in containers in a glasshouse. The soil was amended with 450 kg ha⁻¹ anionic polyacrylamide and 748 mg ha⁻¹ of coal fly ash in factorial combination. Both amendments increased the vegetative yield of the wheat when applied singly, and when they

ARTHUR WALLACE; GARN A. WALLACE

1986-01-01

410

Native and Non-Native Perceptions on a Non-Native Oral Discourse in an Academic Setting  

ERIC Educational Resources Information Center

This qualitative study investigates discourse-level patterns typically employed by a Turkish lecturer based on the syntactic patterns found in the collected data. More specifically, the study aims to reveal how different native and non-native speakers of English perceive discourse patterns used by a non-native lecturer teaching in English. The…

Dikilitas, Kenan; Demir, Bora

2012-01-01

411

The Commodification of the Native in the 21st Century  

E-print Network

Native American cultures, Americans are reinforcing the prejudicesNative Americans, reinforcing negative stereotypes and promoting racial prejudice.Native Americans suffer from the perpetuation of racial prejudices

Fowler, Sarah

2013-01-01

412

Electrophoresis for genotyping: temporal thermal gradient gel electrophoresis for profiling of oligonucleotide dissociation.  

PubMed Central

Traditional use of an oligonucleotide probe to determine genotype depends on perfect base pairing to a single-stranded target which is stable to a higher temperature than when imperfect binding occurs due to a mismatch in the target sequence. Bound oligonucleotide is detected at a predetermined single temperature 'snapshot' of the melting profile, allowing the distinction of perfect from imperfect base pairing. In heterozygotes, the presence of the alternative sequence must be verified with a second oligonucleotide complementary to the variant. Here we describe a system of real-time variable temperature electrophoresis during which the oligonucleotide dissociates from its target. In 20% polyacrylamide the target strand has minimal mobility and released oligonucleotide migrates extremely quickly so that the 'freed' rather than the 'bound' is displayed. The full profile of oligonucleotide dissociation during gel electrophoresis is represented along the gel track, and a single oligonucleotide is sufficient to confirm heterozygosity, since the profile displays two separate peaks. Resolution is great, with use of short track lengths enabling analysis of dense arrays of samples. Each gel track can contain a different target or oligonucleotide and the temperature gradient can accommodate oligonucleotides of different melting temperatures. This provides a convenient system to examine the interaction of many different oligonucleotides and target sequences simultaneously and requires no prior knowledge of the mutant sequence(s) nor of oligonucleotide melting temperatures. The application of the technique is described for screening of a hotspot for mutations in the LDL receptor gene in patients with familial hypercholesterolaemia. Images PMID:7630718

Day, I N; O'Dell, S D; Cash, I D; Humphries, S E; Weavind, G P

1995-01-01

413

76 FR 22413 - Alaska Native Claims Selection  

Federal Register 2010, 2011, 2012, 2013, 2014

...approves the surface estate in the lands described below for conveyance pursuant to the Alaska Native Claims Settlement Act. The subsurface estate in these lands will be conveyed to Koniag, Inc., when the surface estate is conveyed to Afognak Native...

2011-04-21

414

75 FR 53331 - Alaska Native Claims Selection  

Federal Register 2010, 2011, 2012, 2013, 2014

...Hadohdleekaga, Incorporated, for the Native village of Hughes, Alaska, pursuant to the Alaska Native Claims Settlement Act. The subsurface estate in these lands will be conveyed to Doyon, Limited, when the surface estate is conveyed to...

2010-08-31

415

76 FR 3156 - Alaska Native Claims Selection  

Federal Register 2010, 2011, 2012, 2013, 2014

...approves the surface estate in the lands described below for conveyance pursuant to the Alaska Native Claims Settlement Act. The subsurface estate in these lands will be conveyed to Bristol Bay Native Corporation when the surface estate is conveyed to...

2011-01-19

416

Profile: Native Hawaiians and Pacific Islanders  

MedlinePLUS

... origins in any of the original peoples of Hawaii, Guam, Samoa or other Pacific Islands. According to ... 000 Native Hawaiians or Pacific Islanders reside in Hawaii. Some other states that have a significant Native ...

417

Effects of non-native species  

NSDL National Science Digital Library

Species that are not native in a particular area can change the food chain and the environment of the area. Organisms, called biological control agents, may need to be introduced to control the effects of the non-native species.

Olivia Worland (Purdue University; Biological Sciences)

2008-06-25

418

Obesity and Native Hawaiians/Pacific Islanders  

MedlinePLUS

Obesity and Native Hawaiians/Pacific Islanders Native Hawaiians/Pacific Islanders were almost four times more likely to ... data available at this time. HEALTH IMPACT OF OBESITY More than 80 percent of people with type ...

419

Obesity and American Indians/Alaska Natives  

MedlinePLUS

Obesity and American Indians/Alaska Natives American Indian/Alaska Native women are 30% more likely than non- ... findings/nhqrdr/nhqrdr12/index.html HEALTH IMPACT OF OBESITY More than 80 percent of people with type ...

420

NABS Program: (Native Americans in Biological Science).  

ERIC Educational Resources Information Center

Describes the four-week summer program of the Native Americans in Biological Sciences Program that engages Native American eighth- and ninth-grade students in studying the problems related to the waste water treatment plant in Cushing, Oklahoma. (MDH)

Gettys, Nancy, Comp.

1994-01-01

421

History of NASA/Native People Native Homelands Initiative  

NASA Technical Reports Server (NTRS)

This workshop is one of the follow-on local assessment activities from the US National Assessment on the Impact of Climate Change on the US. N. Maynard (for NASA) helped create and get under way an initiative which brought together climate change scientists from around the US with Native Americans to bring together classic Western European scientists with knowledge from native peoples - from such sources as oral histories of drought, major fires, etc. The purpose of this was to encourage not only joint science but also bring NASA resources and education materials to Tribal schools and encourage joint preparation of educational and training materials. N. Maynard's talk will provide history of that process and discuss possible ways to collaborate in the future, building on this effort.

Maynard, Nancy

2000-01-01

422

Thixotropic gel for vadose zone remediation  

DOEpatents

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

Rhia, Brian D. (Augusta, GA)

2011-03-01

423

Health Disparities in the Native Hawaiian Homeless  

PubMed Central

While it is well accepted that Native Hawaiians have poor health statistics compared to other ethnic groups in Hawaii, it is not well documented if these disparities persist when comparing Native Hawaiian homeless individuals to the general homeless population. This paper examines the Native Hawaiian homeless population living in three shelters on the island of Oahu, to determine if there are significant differences in the frequency of diseases between the Native Hawaiian and non-Native Hawaiian homeless. A retrospective data collection was performed using records from the Hawai‘i Homeless Outreach and Medical Education (H.O.M.E.) project. Data from 1182 patients was collected as of 12/05/09. Information collected included patient demographics, frequency of self reported diseases, family history of diseases, risk factors, prevalence of chronic diseases, and most common complaints. The data from Native Hawaiians and non-Native Hawaiians were examined for differences and a 1-tail Fisher exact analysis was done to confirm significance. The data reveals that the Native Hawaiian homeless population is afflicted more frequently with asthma and hypertension compared to other ethnic groups. While diabetes constituted more visits to the clinics for Native Hawaiians compared to the non-Native Hawaiians, there was no significant difference in patient reported prevalence of diabetes. The Native Hawaiian homeless also had increased rates of risky behaviors demonstrated by higher past use of marijuana and methamphetamines. Interestingly, there was a lower use of alcohol in the Native Hawaiian homeless and no significant difference between Native Hawaiians and non-native Hawaiians in current use of illicit drugs, which may represent a hopeful change in behaviors. These troubling statistics show that some of the health disparities seen in the general Native Hawaiian population persist despite the global impoverished state of all homeless. Hopefully, these results will aid organizations like the H.O.M.E. project to better address the health needs of the Native Hawaiian homeless population. PMID:20540000

Oeser, Steffen G; Omori, Jill

2010-01-01

424

Palatability and nutritive value of native legumes  

Microsoft Academic Search

Native perennial legumes have potential for use as components of grazing systems. Palatability affects forage utilization by grazing livestock, but relative palatability of native legumes is unknown. We determined the palatability of these native legumes of the Fabaceae family based on relative leaf consumption: false indigo (Amorpha fruticosa L.), Illinois bundleflower (Desmanthus illinoensis (Michx.) MacMill. ex B.L. Rob. & Fernald),

Donald L Wyse Craig C Sheaffer; Nancy J Ehlke

2009-01-01

425

Native American Studies Major Major Advisors  

E-print Network

Native American Studies Major Major Advisors Laura Jimenez-Olvera & Dewey St. Germaine 532 & 530://ethnicstudies.berkeley.edu/ Undergraduate Program The Native American Studies Program exists to broaden the understanding of students interested in the history, culture, and contemporary situations of Native Americans in the United States

Walker, Matthew P.

426

Native American Children in Michigan. [Executive Summary  

ERIC Educational Resources Information Center

"Native American Children in Michigan," provides a historical context for the tenuous relationship between Michigan's 12 federally recognized tribes and the state government, paying particular attention to the erosion of Native American education programs and the disproportionate number of Native children who find themselves in both the child…

W. K. Kellogg Foundation, 2012

2012-01-01

427

Students Bring Native Texts to Life.  

ERIC Educational Resources Information Center

At Sequoyah Research Center, University of Arkansas, Little Rock, college students receive credit for participating in the Native Writers Digital Text Project. The project identifies, collects, edits, and archives previously unknown or unavailable works by Native writers and constructs bibliographic guides to Native writing and publishing. A web…

Parins, James W.

2003-01-01

428

Generating Textures of New Zealand Native Wood  

E-print Network

1 Generating Textures of New Zealand Native Wood Jack Wang Abstract - This report explores algorithms for computer generated textures simulating New Zealand native wood, we out line procedural and Ray tracing. The main goal of this research is to study New Zealand native wood in depth and to gather

Goodman, James R.

429

Native Fish Society Molalla, OR 97308  

E-print Network

management to protect and recover native wild salmonids that are listed as protected species under 1 Native Fish Society PO Box 568 Molalla, OR 97308 Conserving biological diversity of native fish the Endangered Species Act. The reason advanced for this is that the Council does not have the authority

430

Native Americans and Wage Labor: Ethnohistorical Perspectives.  

ERIC Educational Resources Information Center

This book reconsiders a largely ignored fact of North American Indian economic life--the place of wage labor in the culture and history of Native Americans. Case studies examine social networks of Native agricultural laborers, the decline of Native communities from self-sufficient producers to lower-class wage laborers, vocational education in…

Littlefield, Alice, Ed.; Knack, Martha C., Ed.

431

Effects of anionic polyacrylamide products on gill histopathology in juvenile rainbow trout (Oncorhynchus mykiss).  

PubMed

Anionic polyacrylamide (PAM) products are commonly used to remove suspended materials from turbid waters and to help mitigate soil erosion. In the present study, juvenile rainbow trout (Oncorhynchus mykiss) were exposed to 3?mg/L to 300?mg/L of 10 commercially available PAM products (Clearflow Water Lynx Polymer Log and Clearflow Soil Lynx Granular Polymer; Clearflow Enviro Systems Group), and gill histological parameters were measured following either 7 d or 30 d of polymer exposure. A cationic polymer product (?0.38?mg/L MagnaFloc 368; Ciba Specialty Chemical) was also tested for comparison. Mild gill lesions were observed in fish exposed to polymer products. Lamellar fusion, interlamellar hyperplasia, epithelial lifting, mucous cell metaplasia, and cell counts of epithelial swelling and necrosis/apoptosis were minimal in fish exposed to environmentally relevant concentrations of anionic polymer (?30?mg/L). Gill morphology was largely unaffected by exposure to concentrations up to 300?mg/L of many PAM products. Several anionic polymer products noticeably affected gill tissue by increasing epithelial hypertrophy, interlamellar hyperplasia, mucous cell metaplasia, and the frequency of necrotic cells. The severity of the lesions lessened with time, suggesting that fish may have experienced a short-term irritant effect. Similar levels of gill pathology were frequently observed in fish exposed to cationic polymer MagnaFloc 368 despite the concentration being 1000-fold lower than that of the PAM products. These observations highlight the increased toxicity of cationic polymers to aquatic life compared with anionic PAMs. PMID:24648306

Kerr, Jennifer L; Lumsden, John S; Russell, Spencer K; Jasinska, Edyta J; Goss, Greg G

2014-07-01

432

Influence of polyacrylamide application to soil on movement of microorganisms in runoff water.  

PubMed

Polyacrylamide (PAM) use in irrigation for erosion control has increased water infiltration and reduced soil erosion. This has improved runoff water quality via lower concentrations of nitrogen, phosphorous, and pesticides, and decreased biological oxygen demand. Since non-toxic high molecular weight anionic PAMs removed clay size sediment particles in flowing water, we hypothesized that PAM would effectively remove or immobilize microorganisms in flowing water. In an agricultural field, we determined the efficacy of PAM-treatment of furrow irrigation water to remove several categories of microorganisms in the inflow and runoff. Treatments were: (1) PAM application and a control; (2) three flow rates; (3) two distances from the inflow point; and (4) three times during each irrigation. After water traveled 1 m at 7.5 and 15.5 l min(-1), PAM-treatment reduced total bacterial and microbial biomass and total fungal biomass relative to the control treatment. After water traveled 40 m at 7.5, 15.5, and 22.5 l min(-1), PAM-treatment reduced algae, the numbers active and total bacteria, active and total fungal length, and total bacterial biomass, total fungal and microbial biomass relative to the control treatment. Although specific organisms were not identified or monitored in this study, the results clearly have implications for controlling the spread of soil-borne plant pathogens and other classes of harmful organisms within and among fields via irrigation water and in re-utilized return flows. Beyond furrow-irrigated agriculture, new methods to manage overland transmission of harmful microorganisms could potentially help control transport of pathogens from animal waste in runoff and groundwater. PMID:15092936

Sojka, R E; Entry, J A

2000-06-01

433

Tissue Distribution and Pharmacokinetics of Stable Polyacrylamide Nanoparticles Following Intravenous Injection in the Rat  

PubMed Central

A variety of polymer nanoparticles (NP) are under development for imaging and therapeutic use. However, little is known about their behavior. This study examined pharmacokinetics, distribution and elimination of stable polyacrylamide (PAA) nanoparticles (~31 nm average diameter). PAA-NPs and polyethylene glycol-coated PAA-NPs were injected into the tail veins of healthy male rats. Blood, tissues and excreta were collected at times ranging from 5 minutes to 120 hours and their radioactive content was quantified. A mathematical model was then applied to analyze the distribution dynamics of both NPs. Elimination from the blood could be accounted for by a quick but finite relocation to the major organs (about 20%, 0.6 to 1.3h half-lives), and a slower distribution to the carcass (about 70%, 35 to 43h half-lives). Excreted urinary levels correlated with blood concentrations. Combined cumulative urinary and fecal output accounted for less than 6% of the dose at 120h. Compared to five other polymeric nanoparticles, the studied particles are at the highest half-lives and Area Under the Curve (4000 to 5000 %-h). These two parameters decrease by three orders of magnitude when nanoparticle size increases from the 30 nm range up to 250 nm. For similar sizes, pegylated nanoparticles are more persistent in the blood than non pegylated ones, but this difference is much smaller in the 30 nm and relatively high dose range than above 100 nm. Persistence of PAA NPs is not associated with acute toxicity signs as measured by typical serum markers of inflammation and cellular damage. PMID:21134391

WENGER, Yvan; SCHNEIDER, Randal J.; REDDY, G. Ramachandra; KOPELMAN, Raoul; JOLLIET, Olivier; PHILBERT, Martin A.

2011-01-01

434

Carbonic anhydrase-facilitated CO2 absorption with polyacrylamide buffering bead capture  

SciTech Connect

A novel CO2 separation concept is described wherein the enzyme carbonic anhydrase (CA) is used to increase the overall rate Of CO2 absorption after which hydrated CO2 reacts with regenerable amine-bearing polyacrylamide buffering beads (PABB). Following saturation of the material's immobilized tertiary amines, CA-bearing carrier water is separated and recycled to the absorption stage while CO2-loaded material is thermally regenerated. Process application of this concept would involve operation of two or more columns in parallel with thermal regeneration with low-pressure steam taking place after the capacity of a column of amine-bearing polymeric material was exceeded. PABB CO2- bearing capacity was evaluated by thermogravimetric analysis (TGA) for beads of three acrylamido buffering monomer ingredient concentrations: 0 mol/kg bead, 0.857 mol/kg bead, and 2 mol/kg bead. TGA results demonstrate that CO2- bearing capacity increases with increasing PABB buffering concentration and that up to 78% of the theoretical CO2- bearing capacity was realized in prepared PABB samples (0.857 mol/kg recipe). The highest observed CO2-bearing capacity of PABB was 1.37 mol of CO2 per kg dry bead. TGA was also used to assess the regenerability Of CO2-loaded PABB. Preliminary results suggest that CO2 is partially driven from PABB samples at temperatures as low as 55 degrees C, with complete regeneration occurring at 100 degrees C. Other physical characteristics of PABB are discussed. In addition, the effectiveness of bovine carbonic anhydrase for the catalysis Of CO2 dissolution is evaluated. Potential benefits and drawbacks of the proposed process are discussed. Published by Elsevier Ltd.

Dilmore, R (Dilmore, Robert); Griffith, C (Griffith, Craig); Liu, Z (Liu, Zhu); Soong, Y (Soong, Yee); Hedges, SW (Hedges, Sheila W.); Koepsel, R (Koepsel, Richard); Ataai, M (Ataai, Mohammad)

2009-07-01

435

Effects of cationic polyacrylamide characteristics on sewage sludge dewatering and moisture evaporation.  

PubMed

The effects of the molecular weight (MW) and charge density (CD) of cationic polyacrylamide (CPAM) on sludge dewatering and moisture evaporation were investigated in this study. Results indicated that in sludge conditioning, the optimum dosages were 10, 6, 6, 4, and 4 mg g(-1) CPAM with 5 million MW and 20% CD, 5 million MW and 40% CD, 3 million MW and 40% CD, 8 million MW and 40% CD, and 5 million MW and 60% CD, respectively. The optimum dosage of CPAM was negatively correlated with its CD or MW if the CD or MW of CPAM was above 20% or 5 million. In the centrifugal dewatering of sludge, the moisture content in the conditioned sludge gradually decreased with the extension of centrifugation time, and the economical centrifugal force was 400×g. The moisture evaporation rates of the conditioned sludge were closely related to sludge dewaterability, which was in turn significantly correlated either positively with the solid content of sludge particles that were >2 mm in size or negatively with that of particles measuring 1 mm to 2 mm in diameter. During treatment, sludge moisture content was reduced from 80% to 20% by evaporation, and the moisture evaporation rates were 1.35, 1.49, 1.62, and 2.24 times faster in the sludge conditioned using 4 mg g(-1) CPAM with 5 million MW and 60% CD than in the sludge conditioned using 4 mg g(-1) CPAM with 8 million MW and 40% CD, 6 mg g(-1) CPAM with 5 million MW and 40% CD, 6 mg g(-1) CPAM with 3 million MW and 40% CD, and 10 mg g(-1) CPAM with 5 million MW and 20% CD, respectively. Hence, the CPAM with 5 million MW and 60% CD was ideal for sludge dewatering. PMID:24878582

Zhou, Jun; Liu, Fenwu; Pan, Chengyi

2014-01-01

436

Superporous hybrid hydrogels based on polyacrylamide and chitosan: Characterization and in vitro drug release  

PubMed Central

Objective: Current research was aimed at the development of the drug delivery systems based on the superporous hydrogels (SPH) with the desired swelling and the mechanical properties. Materials and Methods: Superporous hydrogel composites (SPHCs) and superporous hybrid hydrogels (SPHHs) based on the chitosan and the polyacrylamide were synthesized using the gas blowing technique. The prepared hydrogels were evaluated for swelling studies, mechanical strength and scanning electron microscopy. The selected hydrogels were loaded with the drug (verapamil hydrochloride) by aqueous loading method. Drug integrity with in polymeric network was evaluated via fourier transform infrared spectroscopy (FTIR), X-ray diffraction (X-RD), differential scanning calorimetry (DSC), proton nuclear magnetic resonance (1HNMR) studies. In vitro drug release studies were carried out using the united state pharmacopoeial (USP) dissolution apparatus (type II). Results and Discussion: The mechanical strength was observed to be higher in SPH hybrids in comparison to that in SPHCs while no significant difference was observed in swelling behavior. In situ crosslinking of chitosan with glutaraldehyde (GA) may be responsible for high mechanical strength. The equilibrium swelling time was slight higher in SPHH than in SPHCs. The integrity of pores was maintained in ethanol treated hydrogels as observed in scanning electron micrographs. Whereas, freeze dried SPH samples showed non-uniform pores. No drug polymer interaction was observed as indicated by DSC, FTIR, X-RD and NMR studies. However, the crosslinking of chitosan with GA was clearly indicated by these studies. The in vitro drug release studies from SPH hybrids indicated initial fast release (65%) with in first 2 h and then sustained release at the end of 24 h (95%). The addition of hydroxypropyl methyl cellulose with drug; however, leads to a significant decrease in drug release (56% at the end of 24 h). Conclusion: Superporous hybrid hydrogels can be promising devices for the sustained delivery of drug candidates to the gastrointestinal region. PMID:24015380

Nagpal, Manju; Singh, Shailendra Kumar; Mishra, Dinanath

2013-01-01

437

Positive relationship between non-native and native squirrels in an urban landscape  

Microsoft Academic Search

Paradoxically, non-native species sometimes displace native species that appear to be well adapted to local land- scapes. That many landscapes have been altered by humans, creating habitat suitable for non-native species, helps explain this apparent paradox. We asked whether the abundance of native Douglas (Tamiasciurus douglasii (Bachman, 1839)) and northern flying (Glaucomys sabrinus (Shaw, 1801)) squirrels was best explained by

E. K. Gonzales; Y. F. Wiersma; A. I. Maher; T. D. Nudds

2008-01-01

438

Managing Native Grass Forages Patrick Keyser, Professor and Director, Center for Native Grasslands Management  

E-print Network

Managing Native Grass Forages Patrick Keyser, Professor and Director, Center for Native Grasslands Management Fertility Management for Native Grass Forages Native grasses have relatively low fertility of the explanation. There is also some evidence of mycorrhizal relationships that help these grasses fix nitrogen

Tennessee, University of

439

Determinants of Success in Native and Non-Native Listening Comprehension: An Individual Differences Approach  

ERIC Educational Resources Information Center

The goal of this study was to explain individual differences in both native and non-native listening comprehension; 121 native and 113 non-native speakers of Dutch were tested on various linguistic and nonlinguistic cognitive skills thought to underlie listening comprehension. Structural equation modeling was used to identify the predictors of…

Andringa, Sible; Olsthoorn, Nomi; van Beuningen, Catherine; Schoonen, Rob; Hulstijn, Jan

2012-01-01

440

Endophytic and canker-associated Botryosphaeriaceae occurring on non-native Eucalyptus and native Myrtaceae  

E-print Network

regarding the occurrence and species diversity of Botryosphaeriaceae in native Myrtaceae forests or what. nov. are novel species found only on native myrtaceous hosts. Pathogenicity tests showed that isolatesEndophytic and canker-associated Botryosphaeriaceae occurring on non-native Eucalyptus and native

441

NON-NATIVE SPECIES IMPACTS ON NATIVE SALMONIDS IN THE COLUMBIA RIVER BASIN  

E-print Network

NON-NATIVE SPECIES IMPACTS ON NATIVE SALMONIDS IN THE COLUMBIA RIVER BASIN Including Recommendations for Evaluating the Use of Non-Native Fish Species in Resident Fish Substitution Projects Non-native Species Report ISAB 2008-4 #12;Independent Scientific Advisory Board for the Northwest

442

ORIGINAL ARTICLE1 2 The demography of native and non-native plant species  

E-print Network

REVISED PROOF ORIGINAL ARTICLE1 2 The demography of native and non-native plant species 3. In 2009, 14 monitoring plots were established for populations of a non- 15 native species (Linaria dalmatica) and a closely related 16 native species (Castilleja miniata) on an elevation gradient 17

Maxwell, Bruce D.

443

Non-Native Plants Disrupt Dual Promotion of Native Alpha and Beta Diversity  

E-print Network

is published with open access at Springerlink.com Abstract Non-native species can alter patterns of species. Here we show that non-native species reduce native diversity at multiple scales through simultaneous disruption of two processes of native community assembly: species immigration, which enhances alpha diversity

Fukami, Tadashi

444

Native Plants of Montara Mountain  

NSDL National Science Digital Library

It is always inspiring to find websites that have been created by a committed individual who is passionate about the site's subject. Developed by naturalist Chuck Kozak, Native Plants of Montara Mountain is just that type of website. Mr. Kozak has assembled a nice online field guide of plants native to Montara Mountain, a northern spur of California's Santa Cruz Mountains. The guide organizes plants by Family and Scientific name, Common name, or Color and Type. Site visitors can also find plants by using the alphabetically organized Master Index. The numerous plant entries include clear photos and brief descriptions. Although the website focuses on the flora of a specific area, many of these plants can be found in other geographic regions as well. This site is also reviewed in the September 3, 2004 _NSDL Life Sciences Report_.

445

Capillary fracture of soft gels  

NASA Astrophysics Data System (ADS)

A liquid droplet resting on a soft gel substrate can deform that substrate to the point of material failure, whereby fractures develop on the gel surface that propagate outwards from the contact line in a starburst pattern. In this paper, we characterize (i) the initiation process, in which the number of arms in the starburst is controlled by the ratio of the surface tension contrast to the gel's elastic modulus, and (ii) the propagation dynamics showing that once fractures are initiated they propagate with a universal power law L?t3/4. We develop a model for crack initiation by treating the gel as a linear elastic solid and computing the deformations within the substrate from the liquid-solid wetting forces. The elastic solution shows that both the location and the magnitude of the wetting forces are critical in providing a quantitative prediction for the number of fractures and, hence, an interpretation of the initiation of capillary fractures. This solution also reveals that the depth of the gel is an important factor in the fracture process, as it can help mitigate large surface tractions; this finding is confirmed with experiments. We then develop a model for crack propagation by considering the transport of an inviscid fluid into the fracture tip of an incompressible material and find that a simple energy-conservation argument can explain the observed material-independent power law. We compare predictions for both linear elastic and neo-Hookean solids, finding that the latter better explains the observed exponent.

Bostwick, Joshua B.; Daniels, Karen E.

2013-10-01

446

Scanning protein analysis of electrofocusing gels using X-ray fluorescence.  

PubMed

Recently, "metallomics," in addition to genomics and proteomics, has become a focus as a novel approach to identify sensitive fluctuations in homeostasis that accompany metabolic processes, such as stress responses, differentiation, and proliferation. Cellular elements and associated protein behavior provide important clues for understanding cellular and disease mechanism(s). It is important to develop a system for measuring the native status of the protein. In this study, we developed an original freeze-dried electrofocusing native gel over polyimide film (native-gel film) for scanning protein analysis using synchrotron radiation excited X-ray fluorescence (SPAX). To our knowledge, this is the first report detailing the successful mapping of metal-associated proteins of electrofocusing gels using X-ray fluorescence. SPAX can provide detection sensitivity equivalent to that of LA-ICP-MS. In addition to this increased sensitivity, SPAX has the potential to be combined with other X-ray spectroscopies. Our system is useful for further applications in proteomics investigating cellular element-associated protein behaviors and disease mechanisms. PMID:23576194

Matsuyama, Satoshi; Matsunaga, Akihiro; Sakamoto, Shinichi; Iida, Yutaka; Suzuki, Yoshinari; Ishizaka, Yukihito; Yamauchi, Kazuto; Ishikawa, Tetsuya; Shimura, Mari

2013-05-01

447

7th Eastern Native Grass Symposium October 5 -8, 2010  

E-print Network

7th Eastern Native Grass Symposium October 5 - 8, 2010 Knoxville, TN and Natural Landscapes Native Grasses on Working #12;PROCEEDINGS OF THE SEVENTH EASTERN NATIVE GRASS SYMPOSIUM #12;PROCEEDINGS OF THE SEVENTH EASTERN NATIVE GRASS SYMPOSIUM ii SYMPOSIUM

Tennessee, University of

448

Copolymers For Capillary Gel Electrophoresis  

DOEpatents

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

Liu, Changsheng (State College, PA); Li, Qingbo (State College, PA)

2005-08-09

449

Tracer diffusion in colloidal gels  

E-print Network

Computer simulations were done of the mean square displacement (MSD) of tracer particles in colloidal gels formed by diffusion or reaction limited aggregation of hard spheres. The diffusion coefficient was found to be determined by the volume fraction accessible to the spherical tracers ($\\phi_a$) independent of the gel structure or the tracer size. In all cases, critical slowing down was observed at $\\phi_a\\approx 0.03$ and was characterized by the same scaling laws reported earlier for tracer diffusion in a Lorentz gas. Strong heterogeneity of the MSD was observed at small $\\phi_a$ and was related to the size distribution of pores.

Sujin Babu; Jean Christophe Gimel; Taco Nicolai

2007-05-09

450

Tracer diffusion in colloidal gels.  

PubMed

Computer simulations were done of the mean square displacement (MSD) of tracer particles in colloidal gels formed by diffusion or reaction limited aggregation of hard spheres. The diffusion coefficient was found to be determined by the volume fraction accessible to the spherical tracers (phi a) independent of the gel structure or the tracer size. In all cases, critical slowing down was observed at phi a approximately 0.03 and was characterized by the same scaling laws reported earlier for tracer diffusion in a Lorentz gas. Strong heterogeneity of the MSD was observed at small phi a and was related to the size distribution of pores. PMID:18171042

Babu, Sujin; Gimel, Jean Christophe; Nicolai, Taco

2008-01-24

451

Gelatin gels in deuterium oxide  

Microsoft Academic Search

Gelatin gels formed in D2O have greater rigidity than gels of equal concentration formed in H2O. In D2O the junction zones (regions of collagen triple helix structure) were smaller (i.e. involved fewer amino acid residues) than in H2O. The contribution per amino acid residue to the free energy of formation of junction zones was ?0.51kJ\\/mol in D2O compared with ?0.34kJ\\/mol

David Oakenfull; Alan Scott

2003-01-01

452

Screening effect on nanostructure of charged gel  

NASA Astrophysics Data System (ADS)

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

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

2004-07-01

453

Application of chitosan/polyacrylamide nanofibres for removal of chromate and phosphate in water  

NASA Astrophysics Data System (ADS)

Water pollution is an intractable environmental problem in South Africa. Management of the water resource is vital in order to address the water scarcity issues. Research on remediation of contaminated water has focused mainly on the removal of heavy metals such as Pb, Cd, Zn, Hg and Cu and neglected other inorganic pollutants. In this work we focus on the removal of anions, namely chromate and phosphate. Chromium is extensively used in the textile, leather and metallurgy industries and contaminates surface water and groundwater when inadequately treated industrial effluents are discharged. Chromium has been associated with irregular sugar metabolism, nosebleeds and ulcers, and it is also carcinogenic. The phosphate ion is an essential micronutrient responsible for healthy plant growth. However, excess phosphate intake stimulates rapid growth of photosynthetic algae and cyanobacteria, resulting in eutrophication. This phenomenon (algal bloom) causes other organisms to die due to reduced oxygen in the water. In order to offer remediation measures, this study reports the use of electrospun nanofibres for the removal of chromate and phosphate anions. Adsorption experiments were carried out using nanofibres electrospun from chitosan and polyacrylamide polymer blends, cross-linked with glutaraldehyde. Quantification of chromium was done using ICP-OES while UV-Vis spectrophotometry was used for the determination of phosphates. Batch adsorption experiments were done to determine optimum adsorption parameters such as pH, contact time, temperature and initial analyte concentration. Removal of the ions using a flow-adsorption technique through a micro-column was performed. The experimental data obtained were analysed using Langmuir and Freundlich models to study the adsorption mechanisms. The nanofibres had an adsorption capacity for Cr(VI) and PO43- of 0.26 mg g-1 and 392 mg g-1, respectively, and removal efficiencies of 93% and 97.4%, in the same order, in synthetic water samples and environmental water samples. It was observed that both chromium(VI) and phosphate adsorption followed pseudo-second-order kinetics. During the regeneration process, it was established that Cr(VI) was reduced to Cr(III) at the surface of the sorbent. This reaction offers the advantage of reducing the toxicity of chromium(VI) in water. The results of this work have potential applications in the removal of these anions in contaminated drinking water thus improving its quality for human consumption.

Nthumbi, Richard M.; Catherine Ngila, J.; Moodley, Brenda; Kindness, Andrew; Petrik, Leslie

454

Elasticity of c*Gels  

Microsoft Academic Search

A junction affine network model is solved for chains following a Redner des Cloizeaux distribution. In a gel at c^* the network strands behave as isolated chains. In a good solvent their elastic properties cannot be obtained from Gaussian statistics as in the classical models of rubber elasticity. Instead the Redner-des Cloizeaux distribution is employed, which is known to be

Ralf Everaers

1995-01-01

455

Gel Electrophoresis Lab: Paternity Case  

NSDL National Science Digital Library

This lab activity from the Biotechnology Alliance for Suncoast Biology Educators provides instructions for conducting a gel electrophoresis lab. Students will try to solve a paternity case with this activity by obtaining a DNA fingerprint from each potential father, the mother and the child. This activity may be downloaded in PDF file format. A data collection sheet and student questions are also included.

2013-07-05

456

Calculating Percent Gel For Process Control  

NASA Technical Reports Server (NTRS)

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

Webster, Charles Neal; Scott, Robert O.

1988-01-01

457

Regenerative medicine: Noodle gels for cells  

NASA Astrophysics Data System (ADS)

Heating and cooling of peptide amphiphile suspensions converts disorganized nanofibres into liquid-crystalline nanofibre bundles that gel on addition of salts. The noodle-shaped strings of gel can entrap and align cells.

Deming, Timothy J.

2010-07-01

458

Cubic phase gels as drug delivery systems.  

PubMed

Lipids have been used extensively for drug delivery in various forms such as liposomes, and solid-matrices. The focus of this review is evaluation of liquid crystalline cubic phases, spontaneously formed when amphiphilic lipids are placed in aqueous environment, for drug delivery. Cubic phases have an interesting thermodynamically stable structure consisting of curved bicontinuous lipid bilayer in three dimensions, separating two congruent networks of water channels. The unique structure of cubic phase has been extensively studied using various spectroscopic techniques and their resemblance to biomembranes has prompted many scientists to study behavior of proteins in cubic phases. The ability of cubic phase to incorporate and control release of drugs of varying size and polar characteristics, and biodegradability of lipids make it an interesting drug delivery system for various routes of administration. Cubic phases have been shown to deliver small molecule drugs and large proteins by oral and parenteral routes in addition to local delivery in vaginal and periodontal cavity. A number of different proteins in cubic phase appear to retain their native conformation and bioactivity, and are protected from chemical and physical inactivation perhaps due to the reduced activity of water and biomembrane-like structure of cubic phase. Release of drugs from cubic phase typically show diffusion controlled release from a matrix as indicated by Higuchi's square root of time release kinetics. Incorporation of drug in cubic phase can cause phase transformation to lamellar or reversed hexagonal phase depending on the polarity and concentration of the drug, which may affect the release profile. Biodegradability, phase behavior, ability to deliver drugs of varying sizes and polarity and the ability to enhance the chemical and/or physical stability of incorporated drugs and proteins make the cubic phase gel an excellent candidate for use as a drug delivery matrix. However, shorter release duration and the extremely high viscosity may limit its use to specific applications such as periodontal, mucosal, vaginal and short acting oral and parenteral drug delivery. PMID:11311994

Shah, J C; Sadhale, Y; Chilukuri, D M

2001-04-25

459

Raman spectroscopy of blue gel pen inks  

Microsoft Academic Search

Raman spectroscopy is becoming a tool of major importance in forensic science. It is a non-invasive, non-destructive analytical method allowing samples to be examined without any preparation. This paper demonstrates the use of the technique as a general tool for gel pen inks analysis. For this purpose, 55 blue gel pen inks, of different brands and models representative of gel

Williams David Mazzella; Patrick Buzzini

2005-01-01

460

Advanced gel propulsion controls for kill vehicles  

Microsoft Academic Search

A gel propulsion control concept for tactical applications is reviewed, and the status of the individual component technologies currently under development at the Aerojet Propulsion Division is discussed. It is concluded that a gel propellant Divert and Attitude Control Subsystem (DACS) provides a safe, insensitive munitions compliant alternative to current liquid Theater Missile Defense (TMD) DACS approaches. The gel kill

W. K. Yasuhara; A. Olson; S. Finato

1993-01-01

461

Food gels: Gelling process and new applications  

Microsoft Academic Search

Food gels are viscoelastic substances and several gelled products are manufactured throughout the world. The gelling agents in foods are usually polysaccharides and proteins. In food gels, the polymer molecules are not cross-linked by covalent bonds with the exception of disulphide bonds in some protein gels. Instead, the molecules are held together by a combination of weak inter-molecular forces like

SOUMYA BANERJEE; SUVENDU BHATTACHARYA

2011-01-01

462

Food Gels: Gelling Process and New Applications  

Microsoft Academic Search

Food gels are viscoelastic substances and several gelled products are manufactured throughout the world. The gelling agents in foods are usually polysaccharides and proteins. In food gels, the polymer molecules are not cross-linked by covalent bonds with the exception of disulphide bonds in some protein gels. Instead, the molecules are held together by a combination of weak inter-molecular forces like

Soumya Banerjee; Suvendu Bhattacharya

2012-01-01

463

A clarified gel for crystal growth  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

464

Pro-Q Diamond Phosphoprotein Gel Stain  

E-print Network

Pro-Q Diamond Phosphoprotein Gel Stain In-gel Detection Technology for Protein Phosphorylation and phosphoproteomics, the Pro-Q Diamond phos- phoprotein gel stain is a breakthrough technology that provides a simple phosphoproteins, the Pro-Q Diamond signal is linear over three orders of magnitude and the strength of the signal

Lebendiker, Mario