Sample records for brush border membrane

  1. Library of monoclonal antibodies against brush border membrane epithelial antigens

    Energy Technology Data Exchange (ETDEWEB)

    Behar, M.; Katz, A.; Silverman, M.


    A purified fraction of proximal tubule brush border membranes (BBM) was prepared from dog kidney and used to immunize mice. The standard technique of hybridoma production was followed as described by Kohler and Milstein. Production of antibodies was detected by indirect immunofluorescence on dog kidney slices and by immunodot against the purified fraction on nitrocellulose. Five hybrids exhibited anti BBM activity. These were cloned twice and yielded stable cell lines producing IgG type monoclonal antibodies against BBM. They were designated A/sub 1/, C/sub 7/, D/sub 3/, D/sub 7/ and H/sub 4/. As a family these five monoclonals have broad tissue specificity, i.e. positive staining of the surface mucosa of intestinal kidney proximal tubules. D/sub 3/ exhibits even broader specificity for epithelium reacting with bile canaliculi and choroid plexus. The authors have verified that at least 4/5 antibodies are directed against BBM protein as revealed by immunoprecipitation of solubilized BBM and detected by Coomassie blue staining or autoradiography of lactoperoxidase labelled BBM. Most interestingly all antibodies bind to the surface of LL CPK/sub 1/ cells, a continuous pig kidney cell line of undefined origin but exhibiting many characteristics of proximal tubule cells. The library of monoclonal antibodies obtained provide important probes with which to study membrane biogenesis and polarization in epithelial cells.

  2. Dietary free fatty acids form alkaline phosphatase-enriched microdomains in the intestinal brush border membrane

    DEFF Research Database (Denmark)

    Hansen, Gert H; Rasmussen, Karina; Niels-Christiansen, Lise-Lotte;


    -linked enzyme is the membrane protein in the brush border with the highest affinity for lipid rafts, this implies that free fatty acids selectively insert stably into these membrane microdomains. We have previously shown that absorption of dietary lipids transiently induce a selective endocytosis of AP from...... the brush border, and from work by others it is known that fat absorption is accompanied by a rise in serum AP and secretion of surfactant-like particles from enterocytes. We propose that these physiological processes may be triggered by the sequestering of dietary free fatty acids in lipid raft......Free fatty acids released during intralumenal digestion of dietary fat must pass through the enterocyte brush border membrane before triacylglycerol reassembly and subsequent chylomicron delivery to the lymph system. In the present work fluorescent BODIPY fatty acid analogs were used to study...

  3. Calcium competes with zinc for a channel mechanism on the brush border membrane of piglet intestine. (United States)

    Bertolo, R F.P.; Bettger, W J.; Atkinson, S A.


    Interactions between Ca(+2) and Zn(+2) at the intestinal brush border membrane occur via unclear mechanisms. We hypothesized that Zn(+2) and Ca(+2) are transported across the brush border membrane via a multidivalent metal channel. Using brush border membrane vesicles (BBMV) prepared from intestines of 8 sow-fed piglets, we sought to determine whether Ca(+2) competes with Zn(+2) for uptake. Extravesicular Zn(+2) was removed with ethylenediamine-tetraacetic acid. Time curves of Zn(+2) and Ca(+2) uptake by BBMV were conducted with increasing concentrations of Ca(+2) and Zn(+2), respectively. Saturation curves compared kinetic parameters of Zn(+2) uptake with and without Ca(+2). In addition, Zn(+2) uptake was measured in the presence of various classical Ca(+2) channel modulators. Over 20 min, a 0.4x concentration of Zn(+2) lowered Ca(+2) uptake by vesicles, whereas a 30x concentration of Ca(+2) was necessary to lower Zn(+2) uptake. These data suggest that Ca(+2) has lower affinity than Zn(+2) for a brush border membrane transport protein. Kinetic parameters showed higher K(m) values with 4 or 15 mM Ca(+2) but unchanged J(max), suggesting competitive inhibition. The Ca(+2) channel blocking agents, La(+3), Ba(+2), verapamil, and diltiazem, inhibited Zn(+2) uptake, whereas calcitriol, trans 1,2 cyclohexanediol, cis/trans 1,3 cyclohexanediol, and the L-type Ca(+2) channel agonist, Bay K8644, induced Zn(+2) uptake. These data were consistent with competition for a common transport mechanism on the brush border membrane, possibly a novel multimetal channel. Copyright 2001 Elsevier Science Inc.

  4. Generation of stable lipid raft microdomains in the enterocyte brush border by selective endocytic removal of non-raft membrane. (United States)

    Danielsen, E Michael; Hansen, Gert H


    The small intestinal brush border has an unusually high proportion of glycolipids which promote the formation of lipid raft microdomains, stabilized by various cross-linking lectins. This unique membrane organization acts to provide physical and chemical stability to the membrane that faces multiple deleterious agents present in the gut lumen, such as bile salts, digestive enzymes of the pancreas, and a plethora of pathogens. In the present work, we studied the constitutive endocytosis from the brush border of cultured jejunal explants of the pig, and the results indicate that this process functions to enrich the contents of lipid raft components in the brush border. The lipophilic fluorescent marker FM, taken up into early endosomes in the terminal web region (TWEEs), was absent from detergent resistant membranes (DRMs), implying an association with non-raft membrane. Furthermore, neither major lipid raft-associated brush border enzymes nor glycolipids were detected by immunofluorescence microscopy in subapical punctae resembling TWEEs. Finally, two model raft lipids, BODIPY-lactosylceramide and BODIPY-GM1, were not endocytosed except when cholera toxin subunit B (CTB) was present. In conclusion, we propose that constitutive, selective endocytic removal of non-raft membrane acts as a sorting mechanism to enrich the brush border contents of lipid raft components, such as glycolipids and the major digestive enzymes. This sorting may be energetically driven by changes in membrane curvature when molecules move from a microvillar surface to an endocytic invagination.

  5. Generation of stable lipid raft microdomains in the enterocyte brush border by selective endocytic removal of non-raft membrane.

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    E Michael Danielsen

    Full Text Available The small intestinal brush border has an unusually high proportion of glycolipids which promote the formation of lipid raft microdomains, stabilized by various cross-linking lectins. This unique membrane organization acts to provide physical and chemical stability to the membrane that faces multiple deleterious agents present in the gut lumen, such as bile salts, digestive enzymes of the pancreas, and a plethora of pathogens. In the present work, we studied the constitutive endocytosis from the brush border of cultured jejunal explants of the pig, and the results indicate that this process functions to enrich the contents of lipid raft components in the brush border. The lipophilic fluorescent marker FM, taken up into early endosomes in the terminal web region (TWEEs, was absent from detergent resistant membranes (DRMs, implying an association with non-raft membrane. Furthermore, neither major lipid raft-associated brush border enzymes nor glycolipids were detected by immunofluorescence microscopy in subapical punctae resembling TWEEs. Finally, two model raft lipids, BODIPY-lactosylceramide and BODIPY-GM1, were not endocytosed except when cholera toxin subunit B (CTB was present. In conclusion, we propose that constitutive, selective endocytic removal of non-raft membrane acts as a sorting mechanism to enrich the brush border contents of lipid raft components, such as glycolipids and the major digestive enzymes. This sorting may be energetically driven by changes in membrane curvature when molecules move from a microvillar surface to an endocytic invagination.

  6. Faecal excretion of brush border membrane enzymes in patients with clostridium difficile diarrhoea

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    Katyal R


    Full Text Available PURPOSE: To look for the presence of intestinal brush border membrane (BBM enzymes in the faecal samples of patients with Clostridium difficile association. METHODS: One hundred faecal samples were investigated for C.difficile toxin (CDT. Simultaneous assays for faecal excretion of intestinal BBM enzymes viz., disaccharidases, alkaline phosphatase (AP and leucine aminopeptidase (LAP were also done. RESULTS: C.difficile toxin was detected in 25 (25% of the samples with a titre ranging from 10 to 160. No significant difference (p>0.05 was seen between the CDT positive and negative groups with any of the disaccharidases studied. However, significant increase (pC.difficile diarrhoea.

  7. Lipid rafts exist as stable cholesterol-independent microdomains in the brush border membrane of enterocytes

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Immerdal, Lissi; Thorsen, Evy


    Glycosphingolipid/cholesterol-rich membranes ("rafts")can be isolated from many types of cells, but their existence as stable microdomains in the cell membrane has been elusive. Addressing this problem, we studied the distribution of galectin-4, a raft marker, and lactase, a protein excluded from...... rafts, on microvillar vesicles from the enterocyte brush border membrane. Magnetic beads coated with either anti-galectin-4 or anti-lactase antibodies were used for immunoisolation of vesicles followed by double immunogold labeling of the two proteins. A morphometric analysis revealed subpopulations...... of raft-rich and raft-poor vesicles by the following criteria: 1) the lactase/galectin-4 labeling ratio/vesicle captured by the anti-lactase beads was significantly higher (p

  8. Permeability Changes of Manduca sexta Midgut Brush Border Membranes Induced by Oligomeric Structures of Different Cry Toxins

    NARCIS (Netherlands)

    Muñoz-Garay, C.; Sánchez, J.; Darszon, A.; Maagd, de R.A.; Bakker, P.; Soberón, M.; Bravo, A.


    The pore-formation activity of monomeric and oligomeric forms of different Cry1 toxins (from Cry1A to Cry1G) was analyzed by monitoring ionic permeability across Manduca sexta brush border membrane vesicles. The membrane vesicles were isolated from microvilli structures, showing a high enrichment of

  9. Generation of stable lipid raft microdomains in the enterocyte brush border by selective endocytic removal of non-raft membrane

    DEFF Research Database (Denmark)

    Danielsen, E Michael; Hansen, Gert H


    multiple deleterious agents present in the gut lumen, such as bile salts, digestive enzymes of the pancreas, and a plethora of pathogens. In the present work, we studied the constitutive endocytosis from the brush border of cultured jejunal explants of the pig, and the results indicate that this process...... major lipid raft-associated brush border enzymes nor glycolipids were detected by immunofluorescence microscopy in subapical punctae resembling TWEEs. Finally, two model raft lipids, BODIPY-lactosylceramide and BODIPY-GM1, were not endocytosed except when cholera toxin subunit B (CTB) was present....... In conclusion, we propose that constitutive, selective endocytic removal of non-raft membrane acts as a sorting mechanism to enrich the brush border contents of lipid raft components, such as glycolipids and the major digestive enzymes. This sorting may be energetically driven by changes in membrane curvature...

  10. Taurocholate transport by brush-border membrane vesicles from the developing rabbit ileum: Structure/function relationships

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, S.M.; Watkins, J.B.; Ling, S.C. (New York Medical College, Valhalla (USA))


    To examine the ontogenesis of bile acid transport in the rabbit ileum, brush-border membrane vesicles (12- to 20-fold purified) were prepared from 14- to 49-day-old animals. Taurocholate uptake was characterized by the emergence of secondary active, Na(+)-dependent transport at the start of weaning (21 days). Transient intravesicular accumulation (overshoot) of taurocholate occurred at 5-10 s of incubation, and the overshoot maximum increased significantly from 21 days (349.2 +/- 22.4 nmol/mg protein) to 35 days (569.0 +/- 84.3 nmol/mg protein; p less than 0.001), without further increase at maturity (49 days, not equal to 607.6 +/- 136.7 nmol/mg protein). No significant taurocholate active uptake component was noted at 14 days; however, ileal vesicles from sucklings showed carrier-mediated, Na+ D-glucose cotransport. In greater than or equal to 35-day-old rabbits, osmolarity studies at 20 s of incubation showed that only approximately 12% of (14C)taurocholate uptake was secondary to bile acid-to-membrane binding. Conversely, at 20 min, greater than 95% of radiolabel incorporation represented solute bound to the external and/or internal membrane surface. Arrhenius plots establish brush-border membrane taurocholate uptake as an intrinsic, lipid-dependent process, with a slope discontinuity between 24 and 28 degrees C, similar to the membrane lipid thermotropic transition region. Steady-state fluorescence polarization studies (1,6-diphenyl-1,3,5-hexatriene) demonstrate a temporal association between the maturation of taurocholate uptake and age-related decreases in ileal brush-border membrane fluidity. These data indicate that maturation of bile acid secondary active transport in the rabbit ileum may be regulated, at least in part, by changes in brush-border membrane lipid dynamics.

  11. Transport of citrate across renal brush border membrane: effects of dietary acid and alkali loading

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, A.D.; Dousa, T.P.; Smith, L.H.


    Dietary acid or alkali loading was given to rats by providing 150 mM NH4Cl or 150 mM NaHCO3 in place of drinking water for 6 days; control animals received 150 mM NaCl. After 6 days, the citrate clearance was 0.04 +/- 0.01 ml/min (mean +/- SE) in the acid-loaded group, 0.9 +/- 0.1 ml/min in the control group, and 2.5 +/- 0.2 ml/min in the alkali-loaded group. At the end of the experiment, the rats were killed, and the Na gradient-dependent citrate uptake was measured in brush border membrane (BBM) vesicles prepared from each group. At 0.3 min, the ( UC)citrate uptake was 198 +/- 8 pmol/mg protein (mean +/- SE) in the acid-loaded group, 94 +/- 16 pmol/mg protein in the control group, and 94 +/- 13 pmol/mg protein in the alkali-loaded group. The rate of Na -independent (NaCl in medium replaced by KCl) ( UC)-citrate uptake by BBM vesicles was the same for acid-loaded, control, and alkali-loaded animals. Thus, the increased capacity of the proximal tubular BBM to transport citrate from the tubular lumen into the cell interior may be an important factor that contributes to decreased urinary citrate in the presence of metabolic acidosis induced by chronic dietary acid loading.

  12. Ezetimibe Promotes Brush Border Membrane-to-Lumen Cholesterol Efflux in the Small Intestine. (United States)

    Nakano, Takanari; Inoue, Ikuo; Takenaka, Yasuhiro; Ono, Hiraku; Katayama, Shigehiro; Awata, Takuya; Murakoshi, Takayuki


    Ezetimibe inhibits Niemann-Pick C1-like 1 (NPC1L1), an apical membrane cholesterol transporter of enterocytes, thereby reduces intestinal cholesterol absorption. This treatment also increases extrahepatic reverse cholesterol transport via an undefined mechanism. To explore this, we employed a trans-intestinal cholesterol efflux (TICE) assay, which directly detects circulation-to-intestinal lumen 3H-cholesterol transit in a cannulated jejunal segment, and found an increase of TICE by 45%. To examine whether such increase in efflux occurs at the intestinal brush border membrane(BBM)-level, we performed luminal perfusion assays, similar to TICE but the jejunal wall was labelled with orally-given 3H-cholesterol, and determined elevated BBM-to-lumen cholesterol efflux by 3.5-fold with ezetimibe. Such increased efflux probably promotes circulation-to-lumen cholesterol transit eventually; thus increases TICE. Next, we wondered how inhibition of NPC1L1, an influx transporter, resulted in increased efflux. When we traced orally-given 3H-cholesterol in mice, we found that lumen-to-BBM 3H-cholesterol transit was rapid and less sensitive to ezetimibe treatment. Comparison of the efflux and fractional cholesterol absorption revealed an inverse correlation, indicating the efflux as an opposite-regulatory factor for cholesterol absorption efficiency and counteracting to the naturally-occurring rapid cholesterol influx to the BBM. These suggest that the ezetimibe-stimulated increased efflux is crucial in reducing cholesterol absorption. Ezetimibe-induced increase in cholesterol efflux was approximately 2.5-fold greater in mice having endogenous ATP-binding cassette G5/G8 heterodimer, the major sterol efflux transporter of enterocytes, than the knockout counterparts, suggesting that the heterodimer confers additional rapid BBM-to-lumen cholesterol efflux in response to NPC1L1 inhibition. The observed framework for intestinal cholesterol fluxes may provide ways to modulate the flux

  13. Sulfate transport by chick renal tubule brush-border and basolateral membranes

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    Renfro, J.L.; Clark, N.B.; Metts, R.E.; Lynch, M.A.


    Brush-border and basolateral membrane vesicles (BBMV and BLMV, respectively) were prepared from chick kidney by a calcium precipitation method and by centrifugation on an 8% Percoll self-generating gradient, respectively. In BBMV a 100-mM Na gluconate gradient, out>in, caused concentrative (/sup 35/S) sulfate uptake approximately fivefold greater at 1 min than at 60 min (equilibrium) whether or not the membranes were short-circuited with 100 mM K gluconate, in=out, plus 20 valinomycin/mg protein. A 48-mM HCO/sub 3//sup -/ gradient, in>out, stimulated a 2.5-fold higher uptake at 1 min than at 60 min, and short circuiting as above had no effect on the magnitude of this response. Imposition of a H/sup +/ gradient caused concentrative uptake fourfold higher at 1 min than at equilibrium. Short circuiting as above or addition of 0.1 mM carbonyl cyanide m-chlorophenylhydrazone (CCCP) significantly inhibited the pH gradient effect. Creation of an inside positive electrical potential with 100 mM K gluconate, out>in, plus valinomycin, also caused concentrative sulfate uptake. Based on inhibitor/competitor effects, these are distinct sulfate transport processes. In chick BLMV, imposition of an HCO/sub 3//sup -/ gradient, in>out, produced concentrative sulfate uptake. 4-Acetamido-4'-isothiocyanostilbene 2,2'-disulfonic acid disodium at 0.1 mM was an effective inhibitor of BLMV bicarbonate-sulfate exchange.

  14. Selective effect of zinc on uphill transport of oligopeptides into kidney brush border membrane vesicles. (United States)

    Daniel, H; Adibi, S A


    Based on the involvement of zinc in hydrolysis of peptides, we hypothesized that Zn2+ may also play a role in peptide transport. To investigate this hypothesis, kidney brush border membrane vesicles (BBMV) were incubated for 30 min with different concentrations of ZnSO4 before use in uptake studies. This incubation increased by twofold the overshoot uptake of 3H-Gly-L-Gln, D-Leu-125I-Tyr and 3H-cephalexin (all high-affinity substrates for the oligopeptide/H+ symporter) without affecting passive and/or facilitated diffusion of these substrates. Zinc had no effect on the uptake of either glutamine or glucose by kidney BBMV. Among a group of metal ions (cobalt, iron, copper, cadmium, and manganese), only manganese and copper substantially stimulated the activity of the oligopeptide/H+ symporter. DTPA (a complexing agent) inhibited dipeptide uptake, which was reversed by the addition of zinc to the BBMV. Zinc treatment of BBMV reduced the EC50 value of inhibition of 3H-Gly-L-Gln uptake by unlabeled Gly-L-Gln by twofold (90 +/- 8 vs. 45 +/- 4 microM). Similarly, zinc treatment of BBMV reduced the EC50 value for inhibition of D-Leu-125I-Tyr uptake by bestatin from 80 +/- 4 to 40 +/- 3 mM. In conclusion, the data show that zinc has a selective effect on transport of nutrients into kidney BBMV. It stimulates uphill transport of oligopeptides by a modification of their affinity for the binding site of the membrane transporter.

  15. Ezetimibe Promotes Brush Border Membrane-to-Lumen Cholesterol Efflux in the Small Intestine.

    Directory of Open Access Journals (Sweden)

    Takanari Nakano

    Full Text Available Ezetimibe inhibits Niemann-Pick C1-like 1 (NPC1L1, an apical membrane cholesterol transporter of enterocytes, thereby reduces intestinal cholesterol absorption. This treatment also increases extrahepatic reverse cholesterol transport via an undefined mechanism. To explore this, we employed a trans-intestinal cholesterol efflux (TICE assay, which directly detects circulation-to-intestinal lumen 3H-cholesterol transit in a cannulated jejunal segment, and found an increase of TICE by 45%. To examine whether such increase in efflux occurs at the intestinal brush border membrane(BBM-level, we performed luminal perfusion assays, similar to TICE but the jejunal wall was labelled with orally-given 3H-cholesterol, and determined elevated BBM-to-lumen cholesterol efflux by 3.5-fold with ezetimibe. Such increased efflux probably promotes circulation-to-lumen cholesterol transit eventually; thus increases TICE. Next, we wondered how inhibition of NPC1L1, an influx transporter, resulted in increased efflux. When we traced orally-given 3H-cholesterol in mice, we found that lumen-to-BBM 3H-cholesterol transit was rapid and less sensitive to ezetimibe treatment. Comparison of the efflux and fractional cholesterol absorption revealed an inverse correlation, indicating the efflux as an opposite-regulatory factor for cholesterol absorption efficiency and counteracting to the naturally-occurring rapid cholesterol influx to the BBM. These suggest that the ezetimibe-stimulated increased efflux is crucial in reducing cholesterol absorption. Ezetimibe-induced increase in cholesterol efflux was approximately 2.5-fold greater in mice having endogenous ATP-binding cassette G5/G8 heterodimer, the major sterol efflux transporter of enterocytes, than the knockout counterparts, suggesting that the heterodimer confers additional rapid BBM-to-lumen cholesterol efflux in response to NPC1L1 inhibition. The observed framework for intestinal cholesterol fluxes may provide ways to

  16. Sulfate-bicarbonate exchange in brush-border membranes from rat renal cortex

    Energy Technology Data Exchange (ETDEWEB)

    Pritchard, J.B.


    Under Na/sup +/-free conditions /sup 35/SO/sub 4//sup 2 -/ uptake by rat renal brush-border membrane (BBM) vesicles could be driven by imposition of a HCO/sup -//sub 3/ gradient (in greater than out). The initial rate of /sup 35/SO/sub 4//sup 2 -/ uptake was stimulated 10-fold, and peak overshoot exceeded equilibrium uptake by 2-3 times. Cl/sup -/, SCN/sup -/, NO/sub 3//sup -/, I/sup -/, and OH/sup -/ were able to substitute for HCO/sub 3//sup -/. Divalent anions, including /sup 35/SO/sub 4//sup 2 -/ itself, were less effective as counterions. HCO/sub 3//sup -/-SO/sub 4//sup 2 -/ exchange was cis-inhibited by disulfonic stilbenes, ((SITS)(DIDS)), phloretin, Hg, and S/sub 2/O/sub 3//sup 2 -/. HCO/sub 3//sup -/-driven /sup 35/SO/sub 4//sup 2 -/ uptake was saturable, with an apparent K/sub m/ of 0.4 mM for SO/sub 4//sup 2 -/. Simultaneous imposition of Na/sup +/ and HCO/sub 3//sup -/ gradients produced approximately additive stimulation of /sup 35/SO/sub 4//sup 2 -/ uptake. The HCO/sub 3//sup -/-driven component of /sup 35/SO/sub 4//sup 2 -/ uptake, but not the component driven by Na/sup +/, was inhibited by SITS. Finally, Na/sup +/-driven SO/sub 4//sup 2 -/ accumulation could be reduced by imposing an out greater than in HCO/sub 3//sup +/ gradient, conditions accelerating exchange driven SO/sub 4//sup 2 -/ efflux. These findings indicate the presence of separate Na/sup +/-SO/sub 4//sup 2 -/ cotransport and SO /sub 4//sup 2 -/-anion exchange pathways in the same BBM vesicles.

  17. Uptake of /sup 75/Se-selenite by brush border membrane vesicles from chick duodenum stimulated by vitamin D

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    Mykkanen, H.M.; Wasserman, R.H.


    Brush border membrane vesicles were isolated from mucosal homogenates of duodena from normal, rachitic and vitamin D-treated rachitic chicks using a discontinuous sucrose gradient, and further purified by glycerol gradient centrifugation. In vitro uptake of 75Se-selenite by purified brush border membrane vesicles was studied using a rapid filtration technique. The time course of 75Se uptake was non-linear; rapid initial binding was followed by a gradual decrease in the rate of uptake until an equilibrium value was reached at 60-120 min. The initial binding at 36 s was not affected by selenite concentration in the incubation buffer, while the fractional rate of uptake between the 36 s and 2 min time periods was clearly lower with 1 mM Se than with 4-100 microM Se. 75Se uptake did not show any dependency on the external Na-gradient, nor could it be inhibited by other anions (arsenate, phosphate). Treatment of rachitic chicks either with cholecalciferol (500 Iu, 72 h) or with 1,25(OH)2-cholecalciferol (0.5 microgram given 16 h prior to isolation of the vesicles) significantly enhanced 75Se uptake. A threefold excess of mannitol in the outside buffer reduced 75Se uptake by vesicles from vitamin D-deficient and D-treated chicks 60% and 35% respectively, but had no effect on vesicles from vitamin D-treated chicks preloaded with 75Se. Neither saponin treatment nor excess cold selenite could release the label from the vesicles preloaded with 75Se. These data are compatible with the hypothesis that selenite easily crosses the brush border membrane into the intravesicular space and, once inside, is tightly bound by the membrane.

  18. Diabetes increases facilitative glucose uptake and GLUT2 expression at the rat proximal tubule brush border membrane. (United States)

    Marks, Joanne; Carvou, Nicolas J C; Debnam, Edward S; Srai, Surjit K; Unwin, Robert J


    The mechanism of renal glucose transport involves the reabsorption of filtered glucose from the proximal tubule lumen across the brush border membrane (BBM) via a sodium-dependent transporter, SGLT, and exit across the basolateral membrane via facilitative, GLUT-mediated, transport. The aim of the present study was to determine the effect of streptozotocin-induced diabetes on BBM glucose transport. We found that diabetes increased facilitative glucose transport at the BBM by 67.5 % (P < 0.05)--an effect that was abolished by overnight fasting. Western blotting and immunohistochemistry demonstrated GLUT2 expression at the BBM during diabetes, but the protein was undetectable at the BBM of control animals or diabetic animals that had been fasted overnight. Our findings indicate that streptozotocin-induced diabetes causes the insertion of GLUT2 into the BBM and this may provide a low affinity/high capacity route of entry into proximal tubule cells during hyperglycaemia.

  19. Brush border membrane binding properties of Bacillus thuringiensis Vip3A toxin to Heliothis virescens and Helicoverpa zea midguts. (United States)

    Lee, Mi Kyong; Miles, Paul; Chen, Jeng-Shong


    The binding properties of Vip3A, a new family of Bacillus thuringiensis insecticidal toxins, have been examined in the major cotton pests, Heliothis virescens and Helicoverpa zea. Vip3A bound specifically to brush border membrane vesicles (BBMV) prepared from both insect larval midguts. In order to examine the cross-resistance potential of Vip3A to the commercially available Cry1Ac and Cry2Ab2 toxins, the membrane binding site relationship among these toxins was investigated. Competition binding assays demonstrated that Vip3A does not inhibit the binding of either Cry1Ac or Cry2Ab2 and vice versa. BBMV protein blotting experiments showed that Vip3A does not bind to the known Cry1Ac receptors. These distinct binding properties and the unique protein sequence of Vip3A support its use as a novel insecticidal agent. This study indicates a very low cross-resistance potential between Vip3A and currently deployed Cry toxins and hence supports its use in an effective resistance management strategy in cotton.

  20. Specific binding of activated Vip3Aa10 to Helicoverpa armigera brush border membrane vesicles results in pore formation. (United States)

    Liu, Jing-Guo; Yang, Ai-Zhen; Shen, Xiao-Hong; Hua, Bao-Guang; Shi, Guang-Lu


    Helicoverpa armigera is one of the most harmful pests in China. Although it had been successfully controlled by Cry1A toxins, some H. armigera populations are building up resistance to Cry1A toxins in the laboratory. Vip3A, secreted by Bacillus thuringiensis, is another potential toxin against H. armigera. Previous reports showed that activated Vip3A performs its function by inserting into the midgut brush border membrane vesicles (BBMV) of susceptible insects. To further investigate the binding of Vip3A to BBMV of H. armigera, the full-length Vip3Aa10 toxin expressed in Escherichia coli was digested by trypsin or midgut juice extract, respectively. Among the fragments of digested Vip3Aa10, only a 62kDa fragment (Vip3Aa10-T) exhibited binding to BBMV of H. armigera and has insecticidal activity. Moreover, this interaction was specific and was not affected by the presence of Cry1Ab toxin. Binding of Vip3Aa10-T to BBMV resulted in the formation of an ion channel. Unlike Cry1A toxins, Vip3Aa10-T was just slightly associated with lipid rafts of BBMV. These data suggest that although activated Vip3Aa10 specifically interacts with BBMV of H. armigera and forms an ion channel, the mode of action of it may be different from that of Cry1A toxins.

  1. Exploring the midgut transcriptome and brush border membrane vesicle proteome of the rice stem borer, Chilo suppressalis (Walker.

    Directory of Open Access Journals (Sweden)

    Weihua Ma

    Full Text Available The rice stem borer, Chilo suppressalis (Walker (Lepidoptera: Pyralidae, is one of the most detrimental pests affecting rice crops. The use of Bacillus thuringiensis (Bt toxins has been explored as a means to control this pest, but the potential for C. suppressalis to develop resistance to Bt toxins makes this approach problematic. Few C. suppressalis gene sequences are known, which makes in-depth study of gene function difficult. Herein, we sequenced the midgut transcriptome of the rice stem borer. In total, 37,040 contigs were obtained, with a mean size of 497 bp. As expected, the transcripts of C. suppressalis shared high similarity with arthropod genes. Gene ontology and KEGG analysis were used to classify the gene functions in C. suppressalis. Using the midgut transcriptome data, we conducted a proteome analysis to identify proteins expressed abundantly in the brush border membrane vesicles (BBMV. Of the 100 top abundant proteins that were excised and subjected to mass spectrometry analysis, 74 share high similarity with known proteins. Among these proteins, Western blot analysis showed that Aminopeptidase N and EH domain-containing protein have the binding activities with Bt-toxin Cry1Ac. These data provide invaluable information about the gene sequences of C. suppressalis and the proteins that bind with Cry1Ac.

  2. Exploring the midgut transcriptome and brush border membrane vesicle proteome of the rice stem borer, Chilo suppressalis (Walker). (United States)

    Ma, Weihua; Zhang, Zan; Peng, Chuanhua; Wang, Xiaoping; Li, Fei; Lin, Yongjun


    The rice stem borer, Chilo suppressalis (Walker) (Lepidoptera: Pyralidae), is one of the most detrimental pests affecting rice crops. The use of Bacillus thuringiensis (Bt) toxins has been explored as a means to control this pest, but the potential for C. suppressalis to develop resistance to Bt toxins makes this approach problematic. Few C. suppressalis gene sequences are known, which makes in-depth study of gene function difficult. Herein, we sequenced the midgut transcriptome of the rice stem borer. In total, 37,040 contigs were obtained, with a mean size of 497 bp. As expected, the transcripts of C. suppressalis shared high similarity with arthropod genes. Gene ontology and KEGG analysis were used to classify the gene functions in C. suppressalis. Using the midgut transcriptome data, we conducted a proteome analysis to identify proteins expressed abundantly in the brush border membrane vesicles (BBMV). Of the 100 top abundant proteins that were excised and subjected to mass spectrometry analysis, 74 share high similarity with known proteins. Among these proteins, Western blot analysis showed that Aminopeptidase N and EH domain-containing protein have the binding activities with Bt-toxin Cry1Ac. These data provide invaluable information about the gene sequences of C. suppressalis and the proteins that bind with Cry1Ac.

  3. 13C-labeled 18 : 2n-6 recovered in brush border membrane phospholipids short time after administration

    DEFF Research Database (Denmark)

    Vistisen, Bodil; Høy, Carl-Erik


    The purpose of the present study was to examine the short-term effect of dietary specific structured triacylglycerols (MLM, M = 8:0, L = 18:2n-6), LLL and MMM on the fatty acid composition of brush border membrane (BBM) phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Rats were...... administered intragastrically a bolus of ML*M, M*LM*, L*L*L* or M*M*M* (* = C-13- labeled fatty acid). Rats were decapitated 2 hours and 6 hours later, and the fatty acid composition and C-13-enrichment of BBM-PC and -PE were determined. C-13-enriched 18:2n-6 was observed in BBM-PC after intragastric...... fatty acids in the two phospholipid pools. Minor effects on BBM-PC and BBM-PE fatty acid profiles (mole-%) were observed. The present study demonstrated for the first time incorporation of C-13-labeled 18:2n-6 into BBM-PC 2 hours and 6 hours after intragastric administration of L*L*L* or ML...

  4. Galectin-4 and small intestinal brush border enzymes form clusters

    DEFF Research Database (Denmark)

    Danielsen, E M; van Deurs, B


    Detergent-insoluble complexes prepared from pig small intestine are highly enriched in several transmembrane brush border enzymes including aminopeptidase N and sucrase-isomaltase, indicating that they reside in a glycolipid-rich environment in vivo. In the present work galectin-4, an animal lectin...... lacking a N-terminal signal peptide for membrane translocation, was discovered in these complexes as well, and in gradient centrifugation brush border enzymes and galectin-4 formed distinct soluble high molecular weight clusters. Immunoperoxidase cytochemistry and immunogold electron microscopy showed...... by a nonclassical pathway, and the brush border enzymes represent a novel class of natural ligands for a member of the galectin family. Newly synthesized galectin-4 is rapidly "trapped" by association with intracellular structures prior to its apical secretion, but once externalized, association with brush border...

  5. Binding kinetics of Clostridium difficile toxins A and B to intestinal brush border membranes from infant and adult hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Rolfe, R.D. (Texas Tech Univ. Health Sciences Center, Lubbock (USA))


    This study was undertaken to determine if the relative resistance of neonates and infants to Clostridium difficile-associated intestinal disease can be related to age-dependent differences in intestinal receptors for C. difficile toxins A and B. Brush border membranes (BBMs) from the small intestines of adult and infant hamsters were examined for their ability to bind radiolabeled toxins A and B. (125I)toxin A bound to both infant and adult hamster BBMs at physiological temperature, whereas (125I)toxin B did not bind to the BBMs under any of the conditions examined. The number of (125I)toxin A molecules bound at saturation was approximately 4 x 10(10) per micrograms of membrane protein for adult BBMs and 1 x 10(11) per micrograms of membrane protein for infant BBMs. Scatchard plot analysis suggested the presence of a single class of toxin A binding sites on both infant and adult hamster BBMs. Maximal binding capacity and Kd values were 0.63 pmol/mg of protein and 66.7 nM, respectively, for the infant BBMs, and 0.24 pmol/mg of protein and 27 nM, respectively, for the adult BBMs. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analyses of extracted BBM proteins revealed differences in the proteins of infant and adult BBMs. However, there were not any detectable differences in the protein bands which bound (125I)toxin A between infant and adult hamsters. The results from these investigations indicate that differences in the binding kinetics of toxins A and/or B to infant and adult hamster BBMs do not account for the observed differences in their susceptibility to C. difficile-associated intestinal disease.

  6. Lipid rafts in epithelial brush borders: atypical membrane microdomains with specialized functions

    DEFF Research Database (Denmark)

    Danielsen, E Michael; Hansen, Gert H


    of the apical surface sterically accessible for membrane fusion/budding events. Many of these invaginations appear as pleiomorphic, deep apical tubules that extend up to 0.5-1 microm into the underlying terminal web region. Their sensitivity to methyl-beta-cyclodextrin suggests them to contain cholesterol...

  7. Effect of medium-chain glycerides on the membrane transport of D-glucose and sulfanilic acid in the intestinal brush-border membrane vesicles. (United States)

    Sagara, K; Higaki, K; Yamazaki, A; Hashida, M; Sezaki, H


    To clarify the influence of medium-chain glycerides (MCG) on a biological membrane, we investigated the membrane transport of D-glucose and sulfanilic acid in the brush-border membrane (BBM) vesicles pretreated with MCG. The size distribution of the BBM vesicles determined by electron microscopic observation was not significantly different between the vesicles incorporated with MCG and those of the control. However, the amount of D-glucose taken up by the vesicles at an equilibrated stage (30 min) was significantly decreased in the MCG-treated ones based on unit content of protein. Based on these results we estimated the membrane transport of D-glucose and sulfanilic acid in consideration of vesiculation or filter-capturing efficiency in MCG-treated vesicles. The rates of Na+ gradient-independent D-glucose transport and sulfanilic acid transport were significantly greater in MCG-treated vesicles than in the control. On the other hand, the magnitude of overshooting effect in Na+ gradient-dependent uptake of D-glucose in MCG-treated vesicles was maintained similar to the control. Comparison of kinetic parameters for active D-glucose transport at different concentrations indicated that Km and Vmax were not significantly different between MCG-treated and the control vesicles. These results indicated that passive diffusion of D-glucose and sulfanilic acid was significantly increased but Na(+)-glucose cotransporter was not significantly changed by the incorporation of MCG in the intestinal BBM vesicles.

  8. [Effect of natural or synthetic detergents on the transport of D-glucose in the membranes of vesicles of the brush border of the intestine of the rabbit]. (United States)

    Favilli, F; Iantomasi, T; Stio, M; Treves, C; Vanni, P; Vincenzini, M T


    We describe here the effects of natural and synthetic detergents on the D-glucose transport into brush-border membranes of vesicles of rabbit's intestine. Two synthetic detergents: Triton X-100 and dodecyltrimethylammonium bromide have been found very strong inhibitors (more than 50 p. 100 of inhibition of maximal D-glucose uptake). Kinetic studies showed that these detergents behaved as mixed type inhibitors. The Na+-dependent transport of amino acids (aspartic acid, lysine, phenylalanine) is only poorly affected by dodecyltrimethylammonium bromide, while Triton X-100 inhibits unspecifically all the transport studied.

  9. Specificity of Bacillus thuringiensis endotoxins is correlated with the presence of high-affinity binding sites in the brush border membrane of target insect midguts

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, C.; Vanderbruggen, H.; Hoefte, H.; Van Rie, J.; Jansens, S.; Van Mellaert, H. (J. Plateaustraat, Gent (Belgium))


    Binding studies were performed with two {sup 125}I-labeled Bacillus thuringiensis {delta}-endotoxins on brush border membrane vesicles prepared from the larval midgut of the tobacco hornworm Manduca sexta or the cabbage butterfly Pieris brassicae. One {delta}-endotoxin, Bt2-protoxin, is a 130-kDa recombinant crystalline protein from B. thuringiensis subsp. berliner. It kills larvae of both insect species. The active Bt2-toxin is a 60-kDa proteolytic fragment of the Bt2-protoxin. It binds saturably and with high affinity to brush border membrane vesicles from the midgut of both species. The other {delta}-endotoxin, Bt4412-protoxin, is a 136-kDa crystalline protein from B. thuringiensis subsp. thuringiensis, which is highly toxic for P. brassicae, but not for M. sexta larvae. Bt4412-toxin, obtained after proteolytic activation of Bt4412-protoxin, shows high-affinity saturable binding to P. brassicae vesicles but not to M. sexta vesicles. The correlation between toxicity and specific binding is further strengthened by competition studies. Other B. thuringiensis {delta}-endotoxins active against M. sexta compete for binding of {sup 125}I-labeled Bt2-toxin to M. sexta vesicles, whereas toxins active against dipteran or coleopteran larvae do not compete. Bt2-toxin and Bt4412-toxin bind to different sites on P. brassicae vesicles.

  10. Relationship of membrane-bound sulfhydryl groups to vitamin D-stimulated uptake of ( sup 75 Se)Selenite by the brush border membrane vesicles from chick duodenum

    Energy Technology Data Exchange (ETDEWEB)

    Mykkanen, H.M.; Wasserman, R.H. (Cornell Univ., Ithaca, NY (USA))


    The uptake of selenite by purified brush border membrane vesicles isolated from duodena of rachitic or vitamin D-treated chicks was studied by using radioactive selenite and a rapid filtration technique. Cholecalciferol treatment (500 IU at 72 h) significantly enhanced selenite uptake, a response that decreased when the vesicles were stored at room temperature for 2.5 h prior to the uptake measurement. Preincubation of the vesicles in 1.0 mmol/L H2O2 reduced (75Se)selenite uptake, indicating the involvement of oxidizable groups in the uptake reaction. Iodoacetic acid (IAA), a sulfhydryl-blocking reagent, at 1-2 mmol/L concentration eliminated the difference in selenite uptake due to cholecalciferol and had no effect on vesicles from rachitic animals. A higher concentration of IAA (10 mmol/L) enhanced selenite uptake manyfold and increased the absolute difference due to cholecalciferol treatment. Single intravenous doses of 100 IU cholecalciferol, 100 IU ergocalciferol, or 0.1 micrograms 1,25-dihydroxycholecalciferol also stimulated selenite uptake, suggesting a general response to vitamin D compounds. Normal animals given a single dose of 1,25-dihydroxycholecalciferol 12 h prior to killing also responded. Treatments that enhanced the uptake of (75Se)selenite also increased the amount of membrane-bound sulfhydryl groups, suggesting the involvement of membrane-bound sulfhydryl groups in the vitamin D response. A significant increase in selenite uptake by intravenous 1,25-dihydroxycholecalciferol occurred within 10 min. This rapid effect provides a new tool to probe early biochemical effects of vitamin D on intestinal epithelium.

  11. Design of a Photoreactive Analogue of the Escherichia coli Heat-Stable Enterotoxin STIb: Use in Identifying Its Receptor on Rat Brush Border Membranes (United States)

    Gariepy, Jean; Schoolnik, Gary K.


    The Escherichia coli heat-stable enterotoxin, STIb was prepared by solid-phase peptide synthesis and purified to homogeneity by high-pressure liquid chromatography. This analogue was iodinated and shown to bind specifically to rat intestinal membranes. The radiolabeled peptide was derivatized at the amino terminus with the photoreactive heterobifunctional crosslinking agent N-hydroxysuccinimidyl p-benzoylbenzoate. This photoreactive probe also exhibited binding specificity. It was mixed with rat intestinal brush border membranes and photolyzed in the presence or absence of excess unlabeled STIb. Polyacrylamide gel electrophoresis performed in the presence of sodium dodecyl sulfate and 2-mercaptoethanol indicated that the peptide probe was cross-linked specifically to two molecular species of 57 and 75 kDa. One or both of these molecules appear to constitute the enterotoxin receptor or to be in close proximity to it.

  12. A Tenebrio molitor GPI-anchored alkaline phosphatase is involved in binding of Bacillus thuringiensis Cry3Aa to brush border membrane vesicles. (United States)

    Zúñiga-Navarrete, Fernando; Gómez, Isabel; Peña, Guadalupe; Bravo, Alejandra; Soberón, Mario


    Bacillus thuringiensis Cry toxins recognizes their target cells in part by the binding to glycosyl-phosphatidyl-inositol (GPI) anchored proteins such as aminopeptidase-N (APN) or alkaline phosphatases (ALP). Treatment of Tenebrio molitor brush border membrane vesicles (BBMV) with phospholipase C that cleaves out GPI-anchored proteins from the membranes, showed that GPI-anchored proteins are involved in binding of Cry3Aa toxin to BBMV. A 68 kDa GPI-anchored ALP was shown to bind Cry3Aa by toxin overlay assays. The 68 kDa GPI-anchored ALP was preferentially expressed in early instar larvae in comparison to late instar larvae. Our work shows for the first time that GPI-anchored ALP is important for Cry3Aa binding to T. molitor BBMV suggesting that the mode of action of Cry toxins is conserved in different insect orders.

  13. Differential association of the Na+/H+ exchanger regulatory factor (NHERF) family of adaptor proteins with the raft- and the non-raft brush border membrane fractions of NHE3

    NARCIS (Netherlands)

    A. Sultan (Ayesha); M. Luo (Ma); Q. Yu (Qingbao); B. Riederer (Beat Michel); W. Xia (Weiliang); M. Chen (Mingmin); S. Lissner (Simone); J.E. Gessner (Johannes); M. Donowitz (Mark); C. Chris Yun (C.); H. deJonge (Hugo); G. Lamprecht (Georg); U. Seidler (Ursula)


    textabstractBackground/Aims: Trafficking, brush border membrane (BBM) retention, and signal-specific regulation of the Na+/H+ exchanger NHE3 is regulated by the Na+/H+ Exchanger Regulatory Factor (NHERF) family of PDZ-adaptor proteins, which enable the formation of multiprotein complexes. It is uncl

  14. Performance, organ zinc concentration, jejunal brush border membrane enzyme activities and mRNA expression in piglets fed with different levels of dietary zinc. (United States)

    Martin, Lena; Pieper, Robert; Schunter, Nadine; Vahjen, Wilfried; Zentek, Jürgen


    This study aimed at investigating the effect of dietary zinc on performance, jejunal brush border membrane enzyme activities and mRNA levels of enzymes and two zinc transporters in piglets. A total of 126 piglets were weaned at 26 ±1 days of age and randomly allocated into three groups fed with diets 50, 150 and 2500 mg zinc/kg. Performance was recorded and at weekly intervals, eight piglets per group were killed. The activities of isolated brush border membrane enzymes including lactase, maltase, sucrase, aminopeptidase-N and intestinal alkaline phosphatase (IAP), and the relative transcript abundance of aminopeptidase-N (APN), sucrase-isomaltase (SUC), IAP and the two zinc transporters SLC39A4 (ZIP4) and SLC30A1 (ZnT1) were investigated in the jejunum. Feeding pharmacological zinc levels increased weight gain (p < 0.001) during the first week, but performance was lower (p < 0.05) in the third week. Organ zinc concentrations were increased by high dietary zinc level. The activity of IAP was higher (p < 0.05) with the highest dietary zinc level, no effects were determined for other enzymes. Dietary zinc level had no effect on transcript abundance of digestive enzymes. The mRNA levels decreased (p < 0.001) for ZIP4, and increased for ZnT1 (p < 0.05) with pharmacological zinc levels. In conclusion, pharmacological zinc levels improved performance in the short-term. Intestinal mRNA level of zinc transporters changed with high zinc supply, but this did not prevent zinc accumulation in tissues, suggesting hampered homoeostatic regulation. This might cause impaired performance during longer supply.

  15. An azide-insensitive low-affinity ATPase stimulated by Ca2+ or Mg2+ in basal-lateral and brush border membranes of kidney cortex. (United States)

    Ilsbroux, I; Vanduffel, L; Teuchy, H; De Cuyper, M


    Basal-lateral and brush border membranes from pig kidney cortex were prepared by differential centrifugation followed by free-flow electrophoresis. In each type of membrane, azide-insensitive, low-affinity Ca2+-ATPase and Mg2+-ATPase activities are demonstrated. A comparative study for both membranes further reveals the following analogies between these ATPases: (a) they show maximal activity between pH 8 and 8.5; (b) they exhibit Km values for Ca-ATP or Mg-ATP in the millimolar range and have a comparable low substrate specificity; (c) they are insensitive to 10 microM of vanadate, N,N'-dicyclohexylcarbodiimide, e diethylstilbestrol, quercetin, harmaline and amiloride. The partial inhibition by 1 mM of the various compounds is rather aspecific. In view of these similarities it is concluded that only one enzyme entity is responsible for the activity which is measured in both membrane types. The HCO3-stimulated Mg2+-ATPase activity in pig kidney cortex was also studied. This enzyme, however, is clearly of mitochondrial origin since the HCO3-stimulation coincides with the distribution profile of succinate dehydrogenase, a mitochondrial marker; and since it is inhibited by azide.

  16. Leucine transport is affected by Bacillus thuringiensis Cry1 toxins in brush border membrane vesicles from Ostrinia nubilalis Hb (Lepidoptera: Pyralidae) and Sesamia nonagrioides Lefebvre (Lepidoptera: Noctuidae) midgut. (United States)

    Leonardi, M Giovanna; Caccia, Silvia; González-Cabrera, Joel; Ferré, Juan; Giordana, Barbara


    The pore-forming activity of Cry1Ab, Cry1Fa and Cry1Ca toxins and their interaction with leucine transport mediated by the K(+)/leucine cotransporter were studied in brush border membrane vesicles (BBMVs) isolated from the midgut of Ostrinia nubilalis and Sesamia nonagrioides. In both species, as in other Lepidoptera, leucine uptake by BBMVs can take place in the absence of cations, but it can also be driven by a K(+) gradient. Experiments with the voltage-sensitive fluorescent dye 3,3'-diethylthiacarbocyanine iodide proved that Cry1Ab, a Bacillus thuringiensis toxin active in vivo, enhanced the membrane permeability to potassium in O. nubilalis BBMVs. This result is in agreement with similar effects observed in S. nonagrioides BBMV incubated with various Cry1 toxins active in vivo. The effect of the above toxins was tested on the initial rate of 0.1 mM: leucine influx. Instead of an increase in leucine influx, a reduction was observed with the Cry1 toxins active in vivo. Cry1Ab and Cry1Fa, but not the inactive toxin Cry1Da, inhibited in a dose-dependent manner leucine uptake both in the absence and in the presence of a K(+) gradient, a clear indication that their effect is independent of the channel formed by the toxins and that this effect is exerted directly on the amino acid transport system.

  17. The Binding Characterization of Cry Insecticidal Proteins to the Brush Border Membrane Vesicles of Helicoverpa armigera, Spodoptera exigua, Spodoptera litura and Agrotis ipsilon

    Institute of Scientific and Technical Information of China (English)

    LU Qiong; CAO Guang-chun; ZHANG Li-li; LIANG Ge-mei; GAO Xi-wu; ZHANG Yong-jun; GUO Yu-yuan


    Cry toxins produced by Bacillus thuringiensis (Bt) are effective biological insecticides against certain insect species. However, there are potential risks of the evolved resistance of insects to Cry toxin owing to decreased binding of toxins to target sites in the brush border membranes of the larva midgut. The Cry toxins with different binding sites in the larval midgut have been considered to be a good combination to deploy in delaying resistance evolution. Bioassay results demonstrated that the toxicity of different Cry toxins ranked differently for each species. The toxicity ranking was Cry1Ac>Cry1Ab>Cry2Ab for Helicoverpa armigera, Cry1B>Cry1C>Cry2Ab for Spodoptera exigua, and Cry2Ab>Cry1B>Cry1C for S. litura. Only Cry2Ab was toxic to Agrotis ipsilon. Binding experiments were performed with 125I-Cry1Ab, 125I-Cry1Ac, 125I-Cry1B, 125I-Cry1C, 125I-Cry2Ab and the brush border membranes vesicles (BBMV) from H. armigera, S. exigua, S. litura and A. ipsilon. The binding of Cry1Ab and Cry1Ac was shown to be saturable by incubating with increasing concentrations of H. armigera BBMV (Kd=(45.00±2.01) nmol L-1 and (12.80±0.18) nmol L-1, respectively;Bmax=(54.95±1.79) ng and (55.44±0.91) ng, separately). The binding of Cry1B was shown to be saturable by incubating with increasing concentrations of S. exigua BBMV (Kd=(23.26±1.66) nmol L-1;Bmax=(65.37±1.87) ng). The binding of 125I-Cry toxins was shown to be non-saturable by incubating with increasing concentrations of S. litura and A. ipsilon BBMV. In contrast, Cry1B and Cry1C showed some combination with the BBMV of S. litura, and a certain amount of Cry2Ab could bind to the BBMV of A. ipsilon. These observations suggest that a future strategy could be devised for the focused combination of specific cry genes in transgenic crops to control target pests, widen the spectrum of insecticide effectiveness and postpone insect resistance evolution.

  18. Anti-glycosyl antibodies in lipid rafts of the enterocyte brush border: a possible host defense against pathogens

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Pedersen, Esben D K; Immerdal, Lissi;


    The pig small intestinal brush border is a glycoprotein- and glycolipid-rich membrane that functions as a digestive/absorptive surface for dietary nutrients as well as a permeability barrier for pathogens. The present work was performed to identify carbohydrate-binding (lectinlike) proteins...... a major part of the immunoglobulins at the lumenal surface of the gut. The antibodies were associated with lipid rafts at the brush border, and they frequently (52%) coclustered with the raft marker galectin 4. A lactose wash increased the susceptibility of the brush border toward lectin peanut agglutin...... the lipid raft microdomains of the brush border against pathogens....

  19. Effects of different brush border membrane vesicle isolation protocols on proteomic analysis of Cry1 Ac binding proteins from the midgut of Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    Li-Zhen Chen; Ge-Mei Liang; Brian G.Rector; Jie Zhang; Kong-Ming Wu; Yu-Yuan Guo


    Brush border membrane vesicles(BBMV)isolated from insect midguts have been widely used to study CrylA binding proteins.Sample preparation is important in two-dimensional electrophoresis(2-DE),so to determine a suitable BBMV preparation method in Helicoverpa armigera for 2-DE,we compared three published BBMV preparation methods mostly used in sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE).All mctllods yielded similar types and numbers of binding proteins,but in different quantifies.The Abdul.Rauf and Ellar protocol was the best of the three,but had limitations.Sufficient protein qu antity iS important for research involving limited numbers of insects,such as studies of insect resistance to Bacillus thuringiensis in the field.Consequently,we integrated the three BBMV isolation methods into a single protocol that yielded high quantities of BBMV proteins from H.armigera larval midguts.which proved suitable for 2-DE analysis.

  20. Binding Sites for Bacillus thuringiensis Cry2Ae Toxin on Heliothine Brush Border Membrane Vesicles Are Not Shared with Cry1A, Cry1F, or Vip3A Toxin ▿


    Gouffon, C.; van Vliet, A.; Van Rie, J; Jansens, S.; Jurat-Fuentes, J. L.


    The use of combinations of Bacillus thuringiensis (Bt) toxins with diverse modes of action for insect pest control has been proposed as the most efficient strategy to increase target range and delay the onset of insect resistance. Considering that most cases of cross-resistance to Bt toxins in laboratory-selected insect colonies are due to alteration of common toxin binding sites, independent modes of action can be defined as toxins sharing limited or no binding sites in brush border membrane...

  1. Correction of enhanced Na(+)-H+ exchange of rat small intestinal brush-border membranes in streptozotocin-induced diabetes by insulin or 1,25-dihydroxycholecalciferol

    Energy Technology Data Exchange (ETDEWEB)

    Dudeja, P.K.; Wali, R.K.; Klitzke, A.; Sitrin, M.D.; Brasitus, T.A. (Univ. of Chicago, IL (USA))


    Diabetes was induced in rats by administration of a single i.p. injection of streptozotocin (50 mg/kg body wt). After 7 d, diabetic rats were further treated with insulin or 1,25-dihydroxycholecalciferol (1,25(OH)2D3) for an additional 5-7 d. Control, diabetic, diabetic + insulin, and diabetic + 1,25(OH)2D3 rats were then killed, their proximal small intestines were removed, and villus-tip epithelial cells were isolated and used to prepare brush-border membrane vesicles. Preparations from each of these groups were then analyzed and compared with respect to their amiloride-sensitive, electroneutral Na(+)-H+ exchange activity, using {sup 22}Na uptake as well as acridine orange techniques. The results of these experiments demonstrated that (a) H+ gradient-dependent {sup 22}Na uptake as well as Na+ gradient-dependent transmembrane H+ fluxes were significantly increased in diabetic vesicles compared to their control counterparts, (b) kinetic studies demonstrated that this enhanced {sup 22}Na uptake in diabetes was a result of increased maximal velocity (Vmax) of this exchanger with no change in apparent affinity (Km) for Na+, (c) serum levels of 1,25(OH)2D3 were significantly lower in diabetic animals compared with their control counterparts; and (d) insulin or 1,25(OH)2D3 treatment restored the Vmax alterations to control values, without any significant changes in Km, concomitant with significantly increasing the serum levels of 1,25(OH)2D3 in diabetic animals. These results indicate that Na(+)-H+ activity is significantly increased in proximal small intestinal luminal membranes of streptozotocin-induced diabetic rats. Moreover, alterations in the serum levels of 1,25(OH)2D3 may, at least in part, explain this enhanced antiporter activity and its correction by insulin.

  2. Preferential Protection of Domains II and III of Bacillus thuringiensis Cry1Aa Toxin by Brush Border Membrane Vesicles

    Directory of Open Access Journals (Sweden)

    Syed-Rehan A. Hussain


    Full Text Available Título español: Protección preferencial de los dominios II y III de la toxina Cry1Aa de Bacillus thuringiensis en Vesículas de Membrana de Borde de Cepillo Abstract The surface exposed Leucine 371 on loop 2 of domain II, in Cry1Aa toxin, was mutated to Lysine to generate the trypsin-sensitive mutant, L371K. Upon trypsin digestion L371K is cleaved into approximately 37 and 26 kDa fragments. These are separable on SDS-PAGE, but remain as a single molecule of 65 kDa upon purification by liquid chromatography. The larger fragment is domain I and a portion of domain II (amino acid residues 1 to 371. The smaller 26-kDa polypeptide is the remainder of domain II and domain III (amino acids 372 to 609. When the mutant toxin was treated with high dose of M. sexta gut juice both fragments were degraded. However, when incubated with M. sexta BBMV, the 26 kDa fragment (domains II and III was preferentially protected from gut juice proteases. As previously reported, wild type Cry1Aa toxin was also protected against degradation by gut juice proteases when incubated with M. sexta BBMV. On the contrary, when mouse BBMV was added to the reaction mixture neither Cry1Aa nor L371K toxins showed resistance to M. sexta gut juice proteases and were degraded. Since the whole Cry1Aa toxin and most of the domain II and domain III of L371K are protected from proteases in the presence of BBMV of the target insect, we suggest that the insertion of the toxin into the membrane is complex and involves all three domains. Key words: Bacillus thuringiensis, site directed mutagenesis,  -endotoxin. Resumen La superficie de la toxina Cry1Aa, en el asa 2 del dominio II contiene expuesta la leucina 371, la cual fue modificada a lisina produciendo una mutante sensible a la tripsina, L371K. Esta mutante produce dos fragmentos de 37 y 26 kDa por acción de la tripsina que son separables por SDS-PAGE, pero que a la purificación por cromatografía líquida se mantienen como una sola

  3. Pathogenesis of mucosal injury in the blind loop syndrome. Brush border enzyme activity and glycoprotein degradation. (United States)

    Jonas, A; Flanagan, P R; Forstner, G G


    The effect of intestinal bacterial over-growth on brush border hydrolases and brush border glycoproteins was studied in nonoperated control rats, control rats with surgically introduced jejunal self-emptying blind loops, and rats with surgically introduced jejunal self-filling blind loops. Data were analyzed from blind loop segments, segments above and below the blind loops, and three corresponding segments in the nonoperated controls. Rats with self-filling blind loops had significantly greater fat excretion than controls and exhibited significantly lower conjugated:free bile salt ratios in all three segments. Maltase, sucrase, and lactase activities were significantly reduced in homogenates and isolated brush borders from the self-filling blind loop, but alkaline phosphatase was not affected. The relative degradation rate of homogenate and brush border glycoproteins was assessed by a double-isotope technique involving the injection of d-[6-(3)H]glucosamine 3 h and d-[U-(14)C]glucosamine 19 h before sacrifice, and recorded as a (3)H:(14)C ratio. The relative degradation rate in both homogenate and brush border fractions was significantly greater in most segments from rats with self-filling blind loops. In the upper and blind loop segments from rats with self-filling blind loops, the (3)H:(14)C ratios were higher in the brush border membrane than in the corresponding homogenates, indicating that the increased rates of degradation primarily involve membrane glycoproteins. Incorporation of d-[6-(3)H]glucosamine by brush border glycoproteins was not reduced in rats with self-filling blind loops, suggesting that glycoprotein synthesis was not affected. Polyacrylamide gel electrophoresis of brush border glycoproteins from the contaminated segments indicated that the large molecular weight glycoproteins, which include many of the surface hydrolases, were degraded most rapidly. Brush border maltase, isolated by immunoprecipitation, had (3)H:(14)C ratios characteristic of

  4. Molecular model of the microvillar cytoskeleton and organization of the brush border.

    Directory of Open Access Journals (Sweden)

    Jeffrey W Brown

    Full Text Available BACKGROUND: Brush border microvilli are approximately 1-microm long finger-like projections emanating from the apical surfaces of certain, specialized absorptive epithelial cells. A highly symmetric hexagonal array of thousands of these uniformly sized structures form the brush border, which in addition to aiding in nutrient absorption also defends the large surface area against pathogens. Here, we present a molecular model of the protein cytoskeleton responsible for this dramatic cellular morphology. METHODOLOGY/PRINCIPAL FINDINGS: The model is constructed from published crystallographic and microscopic structures reported by several groups over the last 30+ years. Our efforts resulted in a single, unique, self-consistent arrangement of actin, fimbrin, villin, brush border myosin (Myo1A, calmodulin, and brush border spectrin. The central actin core bundle that supports the microvillus is nearly saturated with fimbrin and villin cross-linkers and has a density similar to that found in protein crystals. The proposed model accounts for all major proteinaceous components, reproduces the experimentally determined stoichiometry, and is consistent with the size and morphology of the biological brush border membrane. CONCLUSIONS/SIGNIFICANCE: The model presented here will serve as a structural framework to explain many of the dynamic cellular processes occurring over several time scales, such as protein diffusion, association, and turnover, lipid raft sorting, membrane deformation, cytoskeletal-membrane interactions, and even effacement of the brush border by invading pathogens. In addition, this model provides a structural basis for evaluating the equilibrium processes that result in the uniform size and structure of the highly dynamic microvilli.

  5. Probing endocytosis from the enterocyte brush border using fluorescent lipophilic dyes

    DEFF Research Database (Denmark)

    Danielsen, E Michael


    -toluenesulfonate), and CellMask Orange plasma membrane stain were used to study endocytosis from the enterocyte brush border of organ-cultured porcine mucosal explants. All the dyes readily incorporated into the brush border but were not detectably endocytosed by 5 min, indicating a slow uptake compared with other cell types....... At later time points, FM 1-43 clearly appeared in distinct punctae in the terminal web region, previously shown to represent early endosomes (TWEEs). In contrast, the other dyes were relatively "endocytosis resistant" to varying degrees for periods up to 2 h, indicating an active sorting of lipids...... in the brush border prior to internalization. For some of the dyes, a diphenylhexatriene motif in the lipophilic tail seemed to confer the relative endocytosis resistance. Lipid sorting by selective endocytosis therefore may be a process in the enterocytes aimed to generate and maintain a unique lipid...

  6. Differential Association of the Na+/H+ Exchanger Regulatory Factor (NHERF Family of Adaptor Proteins with the Raft- and the Non-Raft Brush Border Membrane Fractions of NHE3

    Directory of Open Access Journals (Sweden)

    Ayesha Sultan


    Full Text Available Background/Aims: Trafficking, brush border membrane (BBM retention, and signal-specific regulation of the Na+/H+ exchanger NHE3 is regulated by the Na+/H+ Exchanger Regulatory Factor (NHERF family of PDZ-adaptor proteins, which enable the formation of multiprotein complexes. It is unclear, however, what determines signal specificity of these NHERFs. Thus, we studied the association of NHE3, NHERF1 (EBP50, NHERF2 (E3KARP, and NHERF3 (PDZK1 with lipid rafts in murine small intestinal BBM. Methods: Detergent resistant membranes (“lipid rafts” were isolated by floatation of Triton X-incubated small intestinal BBM from a variety of knockout mouse strains in an Optiprep step gradient. Acid-activated NHE3 activity was measured fluorometrically in BCECF-loaded microdissected villi, or by assessment of CO2/HCO3- mediated increase in fluid absorption in perfused jejunal loops of anethetized mice. Results: NHE3 was found to partially associate with lipid rafts in the native BBM, and NHE3 raft association had an impact on NHE3 transport activity and regulation in vivo. NHERF1, 2 and 3 were differentially distributed to rafts and non-rafts, with NHERF2 being most raft-associated and NHERF3 entirely non-raft associated. NHERF2 expression enhanced the localization of NHE3 to membrane rafts. The use of acid sphingomyelinase-deficient mice, which have altered membrane lipid as well as lipid raft composition, allowed us to test the validity of the lipid raft concept in vivo. Conclusions: The differential association of the NHERFs with the raft-associated and the non-raft fraction of NHE3 in the brush border membrane is one component of the differential and signal-specific NHE3 regulation by the different NHERFs.

  7. Lipid raft organization and function in the small intestinal brush border

    DEFF Research Database (Denmark)

    Danielsen, E M; Hansen, Gert Helge


    The enterocyte brush border of the small intestine is a highly specialized membrane designed to function both as a high capacity digestive/absorptive surface of dietary nutrients and a permeability barrier towards lumenal pathogens. It is characterized by an unusually high content of glycolipids...... (approximately 30% of the total microvillar membrane lipid), enabling the formation of liquid ordered microdomains, better known as lipid rafts. The glycolipid rafts are stabilized by galectin-4, a 36 kDa divalent lectin that cross-links galactosyl (and other carbohydrate) residues present on membrane lipids...... proteinases, are protected from untimely release into the gut lumen. Finally, anti-glycosyl antibodies, synthesized by plasma cells locally in the gut, are deposited on the brush border glycolipid rafts, protecting the epithelium from lumenal pathogens that exploit lipid rafts as portals for entry...

  8. Intestinal alkaline phosphatase: selective endocytosis from the enterocyte brush border during fat absorption

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Niels-Christiansen, Lise-Lotte; Immerdal, Lissi;


    Absorption of dietary fat in the small intestine is accompanied by a rise of intestinal alkaline phosphatase (IAP) in the serum and of secretion of IAP-containing surfactant-like particles from the enterocytes. In the present work, fat absorption was studied in organ cultured mouse intestinal...... clathrin-coated pits. By 60 min, IAP was seen in subapical endosomes and along membranes surrounding fat droplets. IAP is a well-known lipid raft-associated protein, and fat absorption was accompanied by a marked change in the density and morphology of the detergent-resistant membranes harboring IAP...... explants. By immunofluorescence microscopy, fat absorption caused a translocation of IAP from the enterocyte brush border to the interior of the cell, whereas other brush-border enzymes were unaffected. By electron microscopy, the translocation occurred by a rapid (5 min) induction of endocytosis via...

  9. Deep-apical tubules: dynamic lipid-raft microdomains in the brush-border region of enterocytes

    DEFF Research Database (Denmark)

    Hansen, Gert H; Pedersen, Jens; Niels-Christiansen, Lise-Lotte


    microdomains. Deep-apical tubules were positioned close to the actin rootlets of adjacent microvilli in the terminal web region, which had a diameter of 50-100 nm, and penetrated up to 1 microm into the cytoplasm. Markers for transcytosis, IgA and the polymeric immunoglobulin receptor, as well as the resident...... lipid raft-containing compartments, but little is otherwise known about these raft microdomains. We therefore studied in closer detail apical lipid-raft compartments in enterocytes by immunogold electron microscopy and biochemical analyses. Novel membrane structures, deep-apical tubules, were visualized...... brush-border enzyme aminopeptidase N, were present in these deep-apical tubules. We propose that deep-apical tubules are a specialized lipid-raft microdomain in the brush-border region functioning as a hub in membrane trafficking at the brush border. In addition, the sensitivity to cholesterol depletion...

  10. Endocytic trafficking from the small intestinal brush border probed with FM dye

    DEFF Research Database (Denmark)

    Hansen, Gert H; Rasmussen, Karina; Niels-Christiansen, Lise-Lotte;


    The small intestinal brush border functions as the body's main portal for uptake of dietary nutrients and simultaneously acts as the largest permeability barrier against pathogens. To enable this, the digestive enzymes of the brush border are organized in lipid raft microdomains stabilized by cross...... localized deeper into the cytoplasm of the enterocytes. Two major raft-associated brush border enzymes, alkaline phosphatase and aminopeptidase N, were excluded from endocytosis. We propose that the terminal web cytoskeleton, by inhibiting traffic from apical early endosomes further into the cell......, contributes to the overall permeability barrier of the gut. Key words: FM dye, small intestine, brush border, endocytosis....

  11. Galectin-2 at the enterocyte brush border of the small intestine

    DEFF Research Database (Denmark)

    Thomsen, Martha Kampp; Hansen, Gert H; Danielsen, E Michael


    boundary. Together with the membrane glycolipids these lectins form stable lipid raft microdomains that also harbour several of the major digestive microvillar enzymes. In the present work, we identified a lactose-sensitive 14-kDa protein enriched in a microvillar detergent resistant fraction as galectin-2......, these results show that the galectins are not simply redundant proteins competing for the same ligands but rather act in concert to ensure an optimal cross-linking of membrane glycolipids and glycoproteins. In this way, they offer a maximal protection of the brush border against exposure to bile, pancreatic...... enzymes and pathogens....

  12. The Secretion and Action of Brush Border Enzymes in the Mammalian Small Intestine. (United States)

    Hooton, Diane; Lentle, Roger; Monro, John; Wickham, Martin; Simpson, Robert


    Microvilli are conventionally regarded as an extension of the small intestinal absorptive surface, but they are also, as latterly discovered, a launching pad for brush border digestive enzymes. Recent work has demonstrated that motor elements of the microvillus cytoskeleton operate to displace the apical membrane toward the apex of the microvillus, where it vesiculates and is shed into the periapical space. Catalytically active brush border digestive enzymes remain incorporated within the membranes of these vesicles, which shifts the site of BB digestion from the surface of the enterocyte to the periapical space. This process enables nutrient hydrolysis to occur adjacent to the membrane in a pre-absorptive step. The characterization of BB digestive enzymes is influenced by the way in which these enzymes are anchored to the apical membranes of microvilli, their subsequent shedding in membrane vesicles, and their differing susceptibilities to cleavage from the component membranes. In addition, the presence of active intracellular components of these enzymes complicates their quantitative assay and the elucidation of their dynamics. This review summarizes the ontogeny and regulation of BB digestive enzymes and what is known of their kinetics and their action in the peripheral and axial regions of the small intestinal lumen.

  13. Binding sites for Bacillus thuringiensis Cry2Ae toxin on heliothine brush border membrane vesicles are not shared with Cry1A, Cry1F, or Vip3A toxin. (United States)

    Gouffon, C; Van Vliet, A; Van Rie, J; Jansens, S; Jurat-Fuentes, J L


    The use of combinations of Bacillus thuringiensis (Bt) toxins with diverse modes of action for insect pest control has been proposed as the most efficient strategy to increase target range and delay the onset of insect resistance. Considering that most cases of cross-resistance to Bt toxins in laboratory-selected insect colonies are due to alteration of common toxin binding sites, independent modes of action can be defined as toxins sharing limited or no binding sites in brush border membrane vesicles (BBMV) prepared from the target insect larvae. In this paper, we report on the specific binding of Cry2Ae toxin to binding sites on BBMV from larvae of the three most commercially relevant heliothine species, Heliothis virescens, Helicoverpa zea, and Helicoverpa armigera. Using chromatographic purification under reducing conditions before labeling, we detected specific binding of radiolabeled Cry2Ae, which allowed us to perform competition assays using Cry1Ab, Cry1Ac, Cry1Fa, Vip3A, Cry2Ae, and Cry2Ab toxins as competitors. In these assays, Cry2Ae binding sites were shared with Cry2Ab but not with the tested Cry1 or Vip3A toxins. Our data support the use of Cry2Ae toxin in combination with Cry1 or Vip3A toxins in strategies to increase target range and delay the onset of heliothine resistance.

  14. Binding Sites for Bacillus thuringiensis Cry2Ae Toxin on Heliothine Brush Border Membrane Vesicles Are Not Shared with Cry1A, Cry1F, or Vip3A Toxin ▿ (United States)

    Gouffon, C.; Van Vliet, A.; Van Rie, J.; Jansens, S.; Jurat-Fuentes, J. L.


    The use of combinations of Bacillus thuringiensis (Bt) toxins with diverse modes of action for insect pest control has been proposed as the most efficient strategy to increase target range and delay the onset of insect resistance. Considering that most cases of cross-resistance to Bt toxins in laboratory-selected insect colonies are due to alteration of common toxin binding sites, independent modes of action can be defined as toxins sharing limited or no binding sites in brush border membrane vesicles (BBMV) prepared from the target insect larvae. In this paper, we report on the specific binding of Cry2Ae toxin to binding sites on BBMV from larvae of the three most commercially relevant heliothine species, Heliothis virescens, Helicoverpa zea, and Helicoverpa armigera. Using chromatographic purification under reducing conditions before labeling, we detected specific binding of radiolabeled Cry2Ae, which allowed us to perform competition assays using Cry1Ab, Cry1Ac, Cry1Fa, Vip3A, Cry2Ae, and Cry2Ab toxins as competitors. In these assays, Cry2Ae binding sites were shared with Cry2Ab but not with the tested Cry1 or Vip3A toxins. Our data support the use of Cry2Ae toxin in combination with Cry1 or Vip3A toxins in strategies to increase target range and delay the onset of heliothine resistance. PMID:21441333

  15. Small molecule pinocytosis and clathrin-dependent endocytosis at the intestinal brush border

    DEFF Research Database (Denmark)

    Danielsen, Erik Michael; Hansen, Gert H


    compartments, indicating the existence of two different uptake mechanisms operating simultaneously at the brush border. CTB is internalized by clathrin-dependent receptor mediated endocytosis, but surprisingly the toxin also caused a rapid disappearance from the apical cell surface of two major brush border...

  16. Developmental changes of jejunal brush-border enzyme activity in growing Jinhua gilts

    Directory of Open Access Journals (Sweden)

    Guo-Wang Li


    Full Text Available The present study was aimed to investigate the developmental changes of small intestinal morphometry and jejunal brush-border enzyme activity in growing Jinhua gilts. The weight, length, and mucosa weight of the small intestine were measured at 35, 80 and 125 days of age, respectively. Sucrase, maltase, lactase and alkaline phosphatase (ALP activities of the jejunal brush-border membrane were determined at the respective stages. Body weights and body weight gains significantly increased with age (P<0.05. Weights of the small intestine and of the intestinal mucosa increased faster from 35 to 80 d than from 80 to 125 d (P<0.05. Weights of the duodenum, jejunum, and ileum, and mucosa from the respective sections increased with age (P<0.05. Mucosa weight relative to the weight of the section was greater (P<0.05 for the duodenum, jejunum than for the ileum. Jejunal maltase and sucrase activity increased with age (P<0.05, whereas, lactose and ALP activity decreased with age (P<0.05 during growth. There was a 15-fold increase in both total jejunal maltase and sucrase activity from 35 to 125 days of age, and a 5-fold increase in both total jejunal lactase and ALP activity; the greatest rate of increase occurred between 35 and 80 days of age. The results suggest increases in body weight of growing Jinhua gilts are accompanied by significant developmental changes in intestinal weight, length and mucosal weights as well as jejunal brush border maltase, sucrase, lactase and ALP activities.

  17. Binding of Cyt1Aa and Cry11Aa toxins of Bacillus thuringiensis serovar israelensis to brush border membrane vesicles of Tipula paludosa (Diptera: Nematocera) and subsequent pore formation. (United States)

    Oestergaard, Jesko; Ehlers, Ralf-Udo; Martínez-Ramírez, Amparo C; Real, Maria Dolores


    Bacillus thuringiensis serovar israelensis (B. thuringiensis subsp. israelensis) produces four insecticidal crystal proteins (ICPs) (Cry4A, Cry4B, Cry11A, and Cyt1A). Toxicity of recombinant B. thuringiensis subsp. israelensis strains expressing only one of the toxins was determined with first instars of Tipula paludosa (Diptera: Nematocera). Cyt1A was the most toxic protein, whereas Cry4A, Cry4B, and Cry11A were virtually nontoxic. Synergistic effects were recorded when Cry4A and/or Cry4B was combined with Cyt1A but not with Cry11A. The binding and pore formation are key steps in the mode of action of B. thuringiensis subsp. israelensis ICPs. Binding and pore-forming activity of Cry11Aa, which is the most toxic protein against mosquitoes, and Cyt1Aa to brush border membrane vesicles (BBMVs) of T. paludosa were analyzed. Solubilization of Cry11Aa resulted in two fragments, with apparent molecular masses of 32 and 36 kDa. No binding of the 36-kDa fragment to T. paludosa BBMVs was detected, whereas the 32-kDa fragment bound to T. paludosa BBMVs. Only a partial reduction of binding of this fragment was observed in competition experiments, indicating a low specificity of the binding. In contrast to results for mosquitoes, the Cyt1Aa protein bound specifically to the BBMVs of T. paludosa, suggesting an insecticidal mechanism based on a receptor-mediated action, as described for Cry proteins. Cry11Aa and Cyt1Aa toxins were both able to produce pores in T. paludosa BBMVs. Protease treatment with trypsin and proteinase K, previously reported to activate Cry11Aa and Cyt1Aa toxins, respectively, had the opposite effect. A higher efficiency in pore formation was observed when Cyt1A was proteinase K treated, while the activity of trypsin-treated Cry11Aa was reduced. Results on binding and pore formation are consistent with results on ICP toxicity and synergistic effect with Cyt1Aa in T. paludosa.

  18. 嗜酸乳杆菌细胞壁提取物对致病性大肠杆菌粘附鸡肠纹状缘膜的影响%Effect of cell wall extracts from Lactobacillus acidophilus on pathogenic E.coli O78 binding to chicken intestinal brush border membranes

    Institute of Scientific and Technical Information of China (English)

    粟硕; 王艳菁; 齐海涛; 王利; 黄震; 陈济铛; 张桂红


    To evaluate the effect of cell wall extracts from Lactobacillus acidophilus on inhibition of chicken pathogenic E. Coli 078 binding to chicken intestinal brush border membrane. We used chicken intestinal brush border membrane treated as a model for the experiment. The activities of surfaces layer proteins, and whole peptidoglycan (WPG) from L. Acidophilus were tested for inhibition of fimbriae-mediated adhesion of E. Coli to chicken intestinal brush border membrane by solid phase binding and binding inhibition assay. The result showed that both S-layer proteins and WPG of L. Acidophilus were able to inhibit the binding of fimbriae with brush border membrane in a dose-dependent manner, which indicated that the mechanism of antagonistic action might be based mainly on space occupancy and competitive binding. Of which the effect of S-layer proteins was stronger than that of WPG.%为研究嗜酸乳杆菌细胞壁提取物对致病性大肠杆菌(E.coli)粘附鸡肠纹状缘膜的影响,本实验以雏鸡小肠纹状缘膜为模型,以嗜酸乳杆菌和鸡致病性E.coli O78为研究对象,提取嗜酸乳杆菌表层蛋白、肽聚糖及E.coli O78菌毛,雏鸡小肠纹状缘膜,采用固相粘附试验和生物素标记法从分子间相互作用的关系评价了嗜酸乳杆菌细胞壁提取物对菌毛粘附的抑制作用,结果表明:表层蛋白和肽聚糖对菌毛粘附具有明显的抑制作用,呈浓度依赖性抑制菌毛与纹状缘膜的结合,具有竞争性拮抗作用,这主要是由空间占位造成的.肽聚糖的抑制作用相对较小.

  19. Protein patterns of brush-border fragments in congenital lactose malabsorption and in specific hypolactasia of the adult. (United States)

    Freiburghaus, A U; Schmitz, J; Schindler, M; Rotthauwe, H W; Kuitunen, P; Launiala, K; Hadorn, B


    Brush-border membrane proteins of the small-bowel mucosa were separated on polyacrylamide gels from intestinal biopsy specimens obtained from four children with congenital lactose malabsorption and from two adults with specific hypolactasia. In three patients with the congenital type of lactase deficiency the protein band corresponding to brush-border lactase was reduced in intensity, but was never completely absent. No difference in gel patterns was detected when this pattern in congenital deficiency was compared to that obtained from the two patients with adult-type selective hypolactasia. In one patient with congenital lactose malabsorption the protein band corresponding to lactase activity was not detectable. The findings suggest that the mechanisms leading to low lactase activity in the congenital and adult forms of lactose intolerance are similar.

  20. Post-translational suppression of expression of intestinal brush border enzymes by fructose

    DEFF Research Database (Denmark)

    Danielsen, E M


    The two major dietary sugars, fructose and sucrose, were found to suppress effectively the biosynthetic renewal of brush border enzymes in the gut. When studied in cultured explants of pig small intestine mucosa, 10-50 mM concentrations of fructose completely prevented the expression of mature...... aminopeptidase N and severely reduced that of sucrase-isomaltase. The instantly occurring and reversible suppressive effect manifested itself as a leupeptin-sensitive degradation of newly synthesized brush border enzymes. The likely mechanism of action of the dietary sugar is by causing an abnormal...... cotranslational glycosylation that in turn triggers a rapid proteolytic breakdown. Our findings suggest that renewal of digestive brush border enzymes is transiently suppressed during intake of fructose- or sucrose-rich meals....

  1. Involvement of detergent-insoluble complexes in the intracellular transport of intestinal brush border enzymes

    DEFF Research Database (Denmark)

    Danielsen, E M


    %), and lactase-phlorizin hydrolase (EC was essentially fully soluble in detergent. In radioactively labeled, mucosal explants, the newly synthesized brush border enzymes began to associate with detergent-insoluble complexes while still in their transient, high mannose-glycosylated form...

  2. Squalamine, a novel cationic steroid, specifically inhibits the brush-border Na+/H+ exchanger isoform NHE3. (United States)

    Akhter, S; Nath, S K; Tse, C M; Williams, J; Zasloff, M; Donowitz, M


    Squalamine, an endogenous molecule found in the liver and other tissues of Squalus acanthias, has antibiotic properties and causes changes in endothelial cell shape. The latter suggested that its potential targets might include transport proteins that control cell volume or cell shape. The effect of purified squalamine was examined on cloned Na+/H+ exchanger isoforms NHE1, NHE2, and NHE3 stably transfected in PS120 fibroblasts. Squalamine (1-h pretreatment) decreased the maximal velocity of rabbit NHE3 in a concentration-dependent manner (13, 47, and 57% inhibition with 3, 5, and 7 micrograms/ml, respectively) and also increased K'[H+]i. Squalamine did not affect rabbit NHE1 or NHE2 function. The inhibitory effect of squalamine was 1) time dependent, with no effect of immediate addition and maximum effect with 1 h of exposure, and 2) fully reversible. Squalamine pretreatment of the ileum for 60 min inhibited brush-border membrane vesicle Na+/H+ activity by 51%. Further investigation into the mechanism of squalamine's effects showed that squalamine required the COOH-terminal 76 amino acids of NHE3. Squalamine had no cytotoxic effect at the concentrations studied, as indicated by monitoring lactate dehydrogenase release. These results indicate that squalamine 1) is a specific inhibitor of the brush-border NHE isoform NHE3 and not NHE1 or NHE2, 2) acts in a nontoxic and fully reversible manner, and 3) has a delayed effect, indicating that it may influence brush-border Na+/H+ exchanger function indirectly, through an intracellular signaling pathway or by acting as an intracellular modulator.

  3. Brush border peptidases and arylamidases in the experimental blind loop syndrome of the rat. (United States)

    Mazzacca, G; Musella, S; Andria, G; D'Agostino, L; Cimino, L; Budillon, G


    Peptidase and arylamidase activities were assessed in purified brush borders from jejunum of rats with surgically created blind loops. The blind loop segment and the jejunum proximal and distal to the blind loop were studied. Comparable jejunal segments from control rats were also studied. The blind loop syndrome was documented by presence of macrocytic anemia. Enzyme activities were determined on purified brush borders. In rats with the blind loop syndromes enzymatic activities hydrolizing sucrose, L-Leucyl-beta-naphthylamide, L-lysyl-beta-naphthylamide, alpha-L-glutamyl-beta-naphthylamide, L-phenylalanyl-alanine and L-leucyl-glycine were significantly reduced as compared to controls (P less than 0.001). After a short course of antibiotic therapy enzymatic activities returned to normal. Our findings suggest a reversible intestinal mucosa damage in the rat with blind loop syndrome.

  4. Effect of lactation on the decline of brush border lactase activity in neonatal pigs.


    Kelly, D.; King, T P; McFadyen, M; Travis, A J


    It has been shown that during the early phase of lactation porcine milk contains high concentrations of hormones and growth factors. The aim of the present investigation was to examine the hypothesis that the temporal coordination of intestinal maturation in piglets can be extrinsically regulated through changes in the composition of milk during the suckling period. Gut morphology and the ontogeny of brush border lactase activity were investigated in piglets reared on two suckling regimens de...

  5. Dietary cholesterol induces trafficking of intestinal Niemann-Pick Type C1 Like 1 from the brush border to endosomes

    DEFF Research Database (Denmark)

    Skov, Marianne; Tønnesen, Carina K; Hansen, Gert H


    early endosome antigen 1, whereas only a minor fraction was left in the brush border. Neither APN, lactase, nor sucrase-isomaltase was endocytosed in parallel, demonstrating that this is a selective cholesterol-induced endocytosis of NPC1L1. Conceivably either the induced internalization could be due...

  6. Apolipoprotein A-1 (apoA-1) deposition in, and release from, the enterocyte brush border

    DEFF Research Database (Denmark)

    Danielsen, E Michael; Hansen, Gert H; Rasmussen, Karina


    Transintestinal cholesterol efflux (TICE) has been proposed to represent a non-hepatobiliary route of cholesterol secretion directly "from blood to gut" and to play a physiologically significant role in excretion of neutral sterols, but so far little is known about the proteins involved in the pr......Transintestinal cholesterol efflux (TICE) has been proposed to represent a non-hepatobiliary route of cholesterol secretion directly "from blood to gut" and to play a physiologically significant role in excretion of neutral sterols, but so far little is known about the proteins involved...... transport (RCT), we propose that brush border-deposited apoA-1 in the small intestine acts in TICE by mediating cholesterol efflux into the gut lumen....

  7. Taurine uptake across the human intestinal brush-border membrane is via two transporters: H+-coupled PAT1 (SLC36A1) and Na+- and Cl−-dependent TauT (SLC6A6)


    Anderson, Catriona M. H.; Howard, Alison; Walters, Julian R F; Ganapathy, Vadivel; Thwaites, David T.


    Taurine is an essential amino acid in some mammals and is conditionally essential in humans. Taurine is an abundant component of meat and fish-based foods and has been used as an oral supplement in the treatment of disorders such as cystic fibrosis and hypertension. The purpose of this investigation was to identity the relative contributions of the solute transporters involved in taurine uptake across the luminal membrane of human enterocytes. Distinct transport characteristics were revealed ...

  8. Apolipoprotein A-1 (apoA-1) deposition in, and release from, the enterocyte brush border: a possible role in transintestinal cholesterol efflux (TICE)? (United States)

    Danielsen, E Michael; Hansen, Gert H; Rasmussen, Karina; Niels-Christiansen, Lise-Lotte; Frenzel, Franz


    Transintestinal cholesterol efflux (TICE) has been proposed to represent a non-hepatobiliary route of cholesterol secretion directly "from blood to gut" and to play a physiologically significant role in excretion of neutral sterols, but so far little is known about the proteins involved in the process. We have previously observed that apolipoprotein A-1 (apoA-1) synthesized by enterocytes of the small intestine is mainly secreted apically into the gut lumen during fasting where its assembly into chylomicrons and basolateral discharge is at a minimal level. In the present work we showed, both by immunomicroscopy and subcellular fractionation, that a fraction of the apically secreted apoA-1 in porcine small intestine was not released from the cell surface but instead deposited in the brush border. Cholesterol was detected in immunoisolated microvillar apoA-1, and it was partially associated with detergent resistant membranes (DRMs), indicative of localization in lipid raft microdomains. The apolipoprotein was not readily released from microvillar vesicles by high salt or by incubation with phosphatidylcholine-specific phospholipase C or trypsin, indicating a relatively firm attachment to the membrane bilayer. However, whole bile or taurocholate efficiently released apoA-1 at low concentrations that did not solubilize the transmembrane microvillar protein aminopeptidase N. Based on these findings and the well known role played by apoA-1 in extrahepatic cellular cholesterol removal and reverse cholesterol transport (RCT), we propose that brush border-deposited apoA-1 in the small intestine acts in TICE by mediating cholesterol efflux into the gut lumen.

  9. Ion induced changes in the structure of bordered pit membranes. (United States)

    Lee, Jinkee; Holbrook, N Michele; Zwieniecki, Maciej A


    Ion-mediated changes in xylem hydraulic resistance are hypothesized to result from hydrogel like properties of pectins located in the bordered pit membranes separating adjacent xylem vessels. Although the kinetics of the ion-mediated changes in hydraulic resistance are consistent with the swelling/deswelling behavior of pectins, there is no direct evidence of this activity. In this report we use atomic force microscopy (AFM) to investigate structural changes in bordered pit membranes associated with changes in the ionic concentration of the surrounding solution. When submerged in de-ionized water, AFM revealed bordered pit membranes as relatively smooth, soft, and lacking any sharp edges surface, in contrast to pictures from scanning electron microscope (SEM) or AFM performed on air-dry material. Exposure of the bordered pit membranes to 50 mM KCl solution resulted in significant changes in both surface physical properties and elevation features. Specifically, bordered pit membranes became harder and the fiber edges were clearly visible. In addition, the membrane contracted and appeared much rougher due to exposed microfibers. In neither solution was there any evidence of discrete pores through the membrane whose dimensions were altered in response to the ionic composition of the surrounding solution. Instead the variable hydraulic resistance appears to involve changes in the both the permeability and the thickness of the pit membrane.

  10. Modifications in the brush border enzymes of the small intestine after irradiation at different times of the day

    Energy Technology Data Exchange (ETDEWEB)

    Becciolini, A.; Lanini, A.; Giache, V.; Balzi, M.; Bini, R. (Florence Univ. (Italy). Ist. di Radiologia)


    The behaviour of the brush border enzyme activity of the intestinal epithelium after the same sublethal radiation dose to the abdomen at different times of the day was investigated. Three previously observed post-irradiation phases (initial increase of activity, reduction, and return to control values) were confirmed, although with some differences. A later return to normal of lactase was also confirmed. The same dose produced different behaviour of the enzyme activities both during the initial and the recovery phase, depending on the time of the day when irradiation was performed, i.e. on the functional condition of the epithelial cells.

  11. Control of biofouling on reverse osmosis polyamide membranes modified with biocidal nanoparticles and antifouling polymer brushes

    KAUST Repository

    Rahaman, Md. Saifur


    Thin-film composite (TFC) polyamide reverse osmosis (RO) membranes are prone to biofouling due to their inherent physicochemical surface properties. In order to address the biofouling problem, we have developed novel surface coatings functionalized with biocidal silver nanoparticles (AgNPs) and antifouling polymer brushes via polyelectrolyte layer-by-layer (LBL) self-assembly. The novel surface coating was prepared with polyelectrolyte LBL films containing poly(acrylic acid) (PAA) and poly(ethylene imine) (PEI), with the latter being either pure PEI or silver nanoparticles coated with PEI (Ag-PEI). The coatings were further functionalized by grafting of polymer brushes, using either hydrophilic poly(sulfobetaine) or low surface energy poly(dimethylsiloxane) (PDMS). The presence of both LBL films and sulfobetaine polymer brushes at the interface significantly increased the hydrophilicity of the membrane surface, while PDMS brushes lowered the membrane surface energy. Overall, all surface modifications resulted in significant reduction of irreversible bacterial cell adhesion. In microbial adhesion tests with E. coli bacteria, a normalized cell adhesion in the range of only 4 to 16% on the modified membrane surfaces was observed. Modified surfaces containing silver nanoparticles also exhibited strong antimicrobial activity. Membranes coated with LBL films of PAA/Ag-PEI achieved over 95% inactivation of bacteria attached to the surface within 1 hour of contact time. Both the antifouling and antimicrobial results suggest the potential of using these novel surface coatings in controlling the fouling of RO membranes. © The Royal Society of Chemistry 2014.

  12. Ion induced changes in the structure of bordered pit membranes

    Directory of Open Access Journals (Sweden)

    Jinkee eLee


    Full Text Available Xylem hydraulic resistance varies with ion concentration in sap solution. It is assumed that this variation in resistance results from hydrogel like properties of pectins located in bordered pit membranes separating adjacent vessels. Although kinetics of the resistance change suggests swelling/deswelling behavior of the pectins, there is no direct evidence of this activity. In this report we provide evidence of structural changes in bordered pit membranes responding to variation in ionic concentration of solute around it using atomic force microscopy (AFM. AFM revealed bordered pit membranes as relatively smooth, soft and lacking any sharp edges surface when submerged in de-ionized water, in contrast to pictures from scanning electron microscope (SEM or AFM performed on air dry material. Exposure of the bordered pit membranes to 50 mM KCl solution resulted in significant changes in both surface physical properties with and elevation features as bordered pit membrane became harder, with visible edges of fibers and collapsed, while no change in porosity was observed. Analysis suggests a need for a major shift in our understanding to the physical bases of variable xylem resistance from change in porosity to change in pathway length. Findings support the role of actuating properties of hybrid hydrogel-cellulose materials in water redistribution and embolism resistance.

  13. Genetic evidence of an accessory activity required specifically for cubilin brush-border expression and intrinsic factor-cobalamin absorption. (United States)

    Xu, D; Kozyraki, R; Newman, T C; Fyfe, J C


    Cubilin is a high molecular weight multiligand receptor that mediates intestinal absorption of intrinsic factor-cobalamin and selective protein reabsorption in renal tubules. The genetic basis of selective intestinal cobalamin malabsorption with proteinuria was investigated in a canine model closely resembling human Imerslund-Gräsbeck syndrome caused by cubilin mutations. Canine CUBN cDNA was cloned and sequenced, showing high identity with human and rat CUBN cDNAs. An intragenic CUBN marker was identified in the canine family and used to test the hypothesis of genetic linkage of the disease and CUBN loci. Linkage was rejected, indicating that the canine disorder resembling Imerslund-Gräsbeck syndrome is caused by defect of a gene product other than cubilin. These results imply that there may be locus heterogeneity among human kindreds with selective intestinal cobalamin malabsorption and proteinuria and that normal brush-border expression of cubilin requires the activity of an accessory protein.

  14. Borders as membranes :metaphors and models for improved policy in border regions.

    Energy Technology Data Exchange (ETDEWEB)

    Malczynski, Leonard A.; Passell, Howard David; Forster, Craig B. (University of Utah, Salt Lake City, UT); Cockerill, Kristan (Cockerill Consulting, Boone, NC)


    Political borders are controversial and contested spaces. In an attempt to better understand movement along and through political borders, this project applied the metaphor of a membrane to look at how people, ideas, and things ''move'' through a border. More specifically, the research team employed this metaphor in a system dynamics framework to construct a computer model to assess legal and illegal migration on the US-Mexico border. Employing a metaphor can be helpful, as it was in this project, to gain different perspectives on a complex system. In addition to the metaphor, the multidisciplinary team utilized an array of methods to gather data including traditional literature searches, an experts workshop, a focus group, interviews, and culling expertise from the individuals on the research team. Results from the qualitative efforts revealed strong social as well as economic drivers that motivate individuals to cross the border legally. Based on the information gathered, the team concluded that legal migration dynamics were of a scope we did not want to consider hence, available demographic models sufficiently capture migration at the local level. Results from both the quantitative and qualitative data searches were used to modify a 1977 border model to demonstrate the dynamic nature of illegal migration. Model runs reveal that current US-policies based on neo-classic economic theory have proven ineffective in curbing illegal migration, and that proposed enforcement policies are also likely to be ineffective. We suggest, based on model results, that improvement in economic conditions within Mexico may have the biggest impact on illegal migration to the U.S. The modeling also supports the views expressed in the current literature suggesting that demographic and economic changes within Mexico are likely to slow illegal migration by 2060 with no special interventions made by either government.

  15. Scavenger receptor class B type I (SR-BI) in pig enterocytes: trafficking from the brush border to lipid droplets during fat absorption

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Niels-Christiansen, Lise-Lotte W; Immerdal, Lissi


    BACKGROUND: Scavenger receptor class B type I (SR-BI) is known to mediate cellular uptake of cholesterol from high density lipoprotein particles and is particularly abundant in liver and steroidogenic tissues. In addition, SR-BI expression in the enterocyte brush border has also been reported...... but its role in the small intestine remains unclear. AIM AND METHODS: To gain insight into the possible function of pig SR-BI during uptake of dietary fat, its localisation in enterocytes was studied in the fasting state and during fat absorption by immunogold electron microscopy and subcellular...... fat, SR-BI is endocytosed from the enterocyte brush border and accumulates in cytoplasmic lipid droplets. Internalisation of the receptor occurs mainly by clathrin coated pits rather than by a caveolae/lipid raft based mechanism....

  16. Ultrathin, freestanding, stimuli-responsive, porous membranes from polymer hydrogel-brushes (United States)

    Kang, Chengjun; Ramakrishna, Shivaprakash N.; Nelson, Adrienne; Cremmel, Clement V. M.; Vom Stein, Helena; Spencer, Nicholas D.; Isa, Lucio; Benetti, Edmondo M.


    The fabrication of freestanding, sub-100 nm-thick, pH-responsive hydrogel membranes with controlled nano-morphology, based on modified poly(hydroxyethyl methacrylate) (PHEMA) is presented. Polymer hydrogel-brush films were first synthesized by surface-initiated atom transfer radical polymerization (SI-ATRP) and subsequently detached from silicon substrates by UV-induced photo-cleavage of a specially designed linker within the initiator groups. The detachment was also assisted by pH-induced osmotic forces generated within the films in the swollen state. The mechanical properties and morphology of the freestanding films were studied by atomic force microscopy (AFM). Inclusion of nanopores of controlled diameter was accomplished by performing SI-ATRP from initiator-coated surfaces that had previously been patterned with polystyrene nanoparticles. Assembly parameters and particle sizes could be varied, in order to fabricate nanoporous hydrogel-brush membranes with tunable pore coverage and characteristics. Additionally, due to the presence of weak polyacid functions within the hydrogel, the membranes exhibited pH-dependent thickness in water and reversible opening/closing of the pores.The fabrication of freestanding, sub-100 nm-thick, pH-responsive hydrogel membranes with controlled nano-morphology, based on modified poly(hydroxyethyl methacrylate) (PHEMA) is presented. Polymer hydrogel-brush films were first synthesized by surface-initiated atom transfer radical polymerization (SI-ATRP) and subsequently detached from silicon substrates by UV-induced photo-cleavage of a specially designed linker within the initiator groups. The detachment was also assisted by pH-induced osmotic forces generated within the films in the swollen state. The mechanical properties and morphology of the freestanding films were studied by atomic force microscopy (AFM). Inclusion of nanopores of controlled diameter was accomplished by performing SI-ATRP from initiator-coated surfaces that had

  17. High flux, positively charged loose nanofiltration membrane by blending with poly (ionic liquid) brushes grafted silica spheres

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Liang [School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou 450001 (China); Zhang, Yatao, E-mail: [School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou 450001 (China); UNESCO Center for Membrane Science and Technology, School of Chemical Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Wang, Yuanming; Zhang, Haoqin [School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou 450001 (China); Liu, Jindun, E-mail: [School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou 450001 (China)


    Highlights: • SiO{sub 2} spheres were modified by poly (ionic liquid) brushes via RATRP. • Positively charged NF membranes were fabricated by incorporation of SiO{sub 2}-PIL. • The membranes exhibited higher rejection for dyes and superior penetration for salts. - Abstract: Silica spheres modified by poly (ionic liquid) brushes, a novel positively charged nanomaterial is prepared by atom transfer radical polymerization (ATRP). A high flux positively charged loose nanofiltration membrane is fabricated via “blending-phase inversion” method. The morphology structures, hydrophilicity, thermal and mechanical properties, permeation performance of these membranes are investigated in detail. The results reveal that the hybrid membranes have enhanced surface hydrophilicity, water permeability, thermal stability, and mechanical properties. Characterization of membrane separation properties shows that the hybrid membranes possess higher salt permeability and relatively higher rejection for reactive dyes, which may open opportunities for the recycling of reactive dyes wastewater. Moreover, such hybrid membranes have an outstanding operational stability and salts concentration showed little effect on the separation properties.

  18. Grafting of carboxybetaine brush onto cellulose membranes via surface-initiated ARGET-ATRP for improving blood compatibility. (United States)

    Wang, Miao; Yuan, Jiang; Huang, Xiaobo; Cai, Xianmei; Li, Li; Shen, Jian


    Grafting-from has proven to be a very effective way to create high grafting densities and well-controlled polymer chains on different kinds of surfaces. In this work, we aim to graft zwitterionic brush from cellulose membrane (CM) via ARGET-ATRP (Activator Regenerated by Electron Transfer ATRP) method indirectly for blood compatibility improvement. Characterization of the CM substrates before and after modification was carried out by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), water contact angle measurements, X-ray photoelectron spectroscopy analysis, and atomic force microscopy, respectively. The results demonstrated zwitterionic brushes were successfully grafted on the CM surfaces, and the content of the grafted layer increased gradually with the polymerization time. The platelet adhesion, hemolytic test and plasma protein adsorption results indicated the cellulose membrane had significantly excellent blood compatibility featured on lower platelet adhesion and protein adsorption without causing hemolysis. The functionalized cellulose substrate could have a great potential usage for biomedical applications.

  19. High flux, positively charged loose nanofiltration membrane by blending with poly (ionic liquid) brushes grafted silica spheres. (United States)

    Yu, Liang; Zhang, Yatao; Wang, Yuanming; Zhang, Haoqin; Liu, Jindun


    Silica spheres modified by poly (ionic liquid) brushes, a novel positively charged nanomaterial is prepared by atom transfer radical polymerization (ATRP). A high flux positively charged loose nanofiltration membrane is fabricated via "blending-phase inversion" method. The morphology structures, hydrophilicity, thermal and mechanical properties, permeation performance of these membranes are investigated in detail. The results reveal that the hybrid membranes have enhanced surface hydrophilicity, water permeability, thermal stability, and mechanical properties. Characterization of membrane separation properties shows that the hybrid membranes possess higher salt permeability and relatively higher rejection for reactive dyes, which may open opportunities for the recycling of reactive dyes wastewater. Moreover, such hybrid membranes have an outstanding operational stability and salts concentration showed little effect on the separation properties.

  20. "Nonclassical" secretion of annexin A2 to the lumenal side of the enterocyte brush border membrane

    DEFF Research Database (Denmark)

    Danielsen, E Michael; van Deurs, Bo; Hansen, Gert H


    side of the microvilli, showing an apical secretion by a "nonclassical" mechanism. In addition, annexin A2 was associated with surface-connected, deep apical tubules in the apical terminal web region and with an underlying pleiomorphic, tubulo-vesicular compartment (subapical compartment...


    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...


    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...


    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  4. Thiolation of polycarbophil enhances its inhibition of intestinal brush border membrane bound aminopeptidase N. (United States)

    Bernkop-Schnürch, A; Zarti, H; Walker, G F


    The purpose of this study was to evaluate the potential of polycarbophil-cysteine conjugates (PCP-Cys) as an oral excipient to protect leucine enkephalin (leu-enkp) from enzymatic degradation by the intestinal mucosa. Cysteine was covalently linked to polycarbophil by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC). Inhibitory activity was tested towards isolated aminopeptidase N and excised intact pig intestinal mucosa, with native mucus. Aminopeptidase N activity was assayed spectrophotometrically using L-leucine p-nitroanilide (leu-pNA) as a synthetic substrate and against the model peptide drug leu-enkp, by high-performance liquid chromatography (HPLC). Free cysteine at 6.3 and 63 microM (pH 6) significantly (p < 0.05) inhibited aminopeptidase N activity, and PCP-Cys (0.25% w/v, pH 6) had a significantly (p < 0.05) greater inhibitory effect than PCP on the aminopeptidase N activity towards both substrates. PCP-Cys completely protected leu-enkp against aminopeptidase N activity over a 2-h incubation period, whereas 83 +/- 4 and 60 +/- 7% remained stable in the presence of PCP and buffer only, respectively. Leu-enkp in the absence and presence of PCP (0.25% w/v) at pH 6 was completely digested by the intact intestinal mucosa at the 60- and 90-min incubation time points, respectively, whereas in the presence of PCP-Cys (0.25% w/v, pH 6) 11 +/- 3.5% of leu-enkp remained at the 120-min time point. Thiolation of PCP increased the stability of leu-enkp against the enzymatic degradation by aminopeptidase N and the intact intestinal mucosa, identifying a promising new excipient for peroral delivery of peptides.

  5. Controlled Architecture of Dual-Functional Block Copolymer Brushes on Thin-Film Composite Membranes for Integrated "Defending" and "Attacking" Strategies against Biofouling. (United States)

    Ye, Gang; Lee, Jongho; Perreault, François; Elimelech, Menachem


    We report a new macromolecular architecture of dual functional block copolymer brushes on commercial thin-film composite (TFC) membranes for integrated "defending" and "attacking" strategies against biofouling. Mussel-inspired catechol chemistry is used for a convenient immobilization of initiator molecules to the membrane surface with the aid of polydopamine (PDA). Zwitterionic polymer brushes with strong hydration capacity and quaternary ammonium salt (QAS) polymer brushes with bactericidal ability are sequentially grafted on TFC membranes via activators regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP), an environmentally benign and controlled polymerization method. Measurement of membrane intrinsic transport properties in reverse osmosis experiments shows that the modified TFC membrane maintains the same water permeability and salt selectivity as the pristine TFC membrane. Chemical force microscopy and protein/bacterial adhesion studies are carried out for a comprehensive evaluation of the biofouling resistance and antimicrobial ability, demonstrating low biofouling propensity and excellent bacterial inactivation for the modified TFC membrane. We conclude that this polymer architecture, with complementary "defending" and "attacking" capabilities, can effectively prevent the attachment of biofoulants and formation of biofilms and thereby significantly mitigate biofouling on TFC membranes.

  6. Humic acid removal and easy-cleanability using temperature-responsive ZrO2 tubular membranes grafted with poly(N-isopropylacrylamide) brush chains. (United States)

    Zhao, Yijiang; Zhou, Shouyong; Li, Meisheng; Xue, Ailian; Zhang, Yan; Wang, Jingang; Xing, Weihong


    New poly(N-isopropylacrylamide) brushes grafted with ZrO2 (PNIPAAm-g-ZrO2) composite membranes, which had been prepared in our laboratory, were used for humic acid (HA) removal. We found that the fluxes associated with such membranes, when compared to those obtained from unmodified ZrO2 membranes, declined slightly at both 25 °C and 35 °C. The PNIPAAm-g-ZrO2 membrane achieved a high rejection, of 98.0%, at a suitable steady flux of 111.9 L m(-2) h(-1) at 25 °C. This membrane exhibited good anti-fouling properties as well as improved membrane performance during filtration of HA. The important role of pH and Ca(2+) concentration in HA removal was also investigated. Lower adsorption fouling and a higher rejection were obtained at higher pH levels. The Ca(2+) ions reduced the electrostatic exclusion and played a cross-linking role between HA and the PNIPAAm-g-ZrO2 membrane surface. Fouling was severe in the presence of Ca(2+). These tests led to the development of an environment-friendly membrane cleaning method, by means of temperature-change water elution around LCST of PNIPAAm-brushes. After the alternate temperature-change (25 °C/35 °C) cleaning, a flux recovery of 98.2% was obtained for the PNIPAAm-g-ZrO2 membrane. Moreover, after four repeated experiments, the anti-fouling and easy-cleaning properties were still maintained. It is implied that PNIPAAm-brushes were firmly "stuck" to the membrane surface, and could not easily be removed by water cleaning or HA filtration. The PNIPAAm-g-ZrO2 membranes exhibited good stability and great potential for HA removal.

  7. In vitro test on the ability of a yeast cell wall based product to inhibit the Escherichia coli F4ac adhesion on the brush border of porcine intestinal villi. (United States)

    Trevisi, P; Priori, D; Gandolfi, G; Colombo, M; Coloretti, F; Goossens, T; Bosi, P


    The ability of a yeast cell wall (YCW)-based product (SENTIGUARD C; Nutriad) to inhibit the enterotoxigenic Escherichia coli F4ac (ETEC) adhesion on the brush border of porcine intestinal villi was tested. The ETEC suspensions were preincubated with 2 batches of the product (A and B) at different concentrations (10, 5, and 0.5%, wt/vol) or with their filtrates (AF and BF) and then with intestinal villi susceptible to ETEC adhesion. In all the trials, ETEC suspensions were also preincubated with egg yolk (E) immunized against ETEC to assess the maximum inhibition of the adhesiveness or directly with the villi [control group (Con)] to verify the maximum adhesiveness of the pathogen. For each treatment, 20 different villi were observed, brush border measured, and the adherent pathogens counted. A scanning electron microscope analysis was used to confirm the ability of ETEC to adhere on the YCW. The E treatment significantly reduced the pathogen adhesion on the villi compared with the C group in all the trials (P intestinal infection from ETEC in young pigs with the affinity of ETEC to YCW.

  8. Polymer Brushes

    NARCIS (Netherlands)

    Vos, de W.M.; Kleijn, J.M.; Keizer, de A.; Cosgrove, T.; Cohen Stuart, M.A.


    A polymer brush can be defined as a dense array of polymers end-attached to an interface that stretch out into the surrounding medium. Polymer brushes have been investigated for the past 30 years and have shown to be an extremely useful tool to control interfacial properties. This review is intended

  9. Hemocompatibility of poly(vinylidene fluoride) membrane grafted with network-like and brush-like antifouling layer controlled via plasma-induced surface PEGylation. (United States)

    Chang, Yung; Shih, Yu-Ju; Ko, Chao-Yin; Jhong, Jheng-Fong; Liu, Ying-Ling; Wei, Ta-Chin


    In this work, the hemocompatibility of PEGylated poly(vinylidene fluoride) (PVDF) microporous membranes with varying grafting coverage and structures via plasma-induced surface PEGylation was studied. Network-like and brush-like PEGylated layers on PVDF membrane surfaces were achieved by low-pressure and atmospheric plasma treatment. The chemical composition, physical morphology, grafting structure, surface hydrophilicity, and hydration capability of prepared membranes were determined to illustrate the correlations between grafting qualities and hemocompatibility of PEGylated PVDF membranes in contact with human blood. Plasma protein adsorption onto different PEGylated PVDF membranes from single-protein solutions and the complex medium of 100% human plasma were measured by enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies. Hemocompatibility of the PEGylated membranes was evaluated by the antifouling property of platelet adhesion observed by scanning electron microscopy (SEM) and the anticoagulant activity of the blood coagulant determined by testing plasma-clotting time. The control of grafting structures of PEGylated layers highly regulates the PVDF membrane to resist the adsorption of plasma proteins, the adhesion of platelets, and the coagulation of human plasma. It was found that PVDF membranes grafted with brush-like PEGylated layers presented higher hydration capability with binding water molecules than with network-like PEGylated layers to improve the hemocompatible character of plasma protein and blood platelet resistance in human blood. This work suggests that the hemocompatible nature of grafted PEGylated polymers by controlling grafting structures gives them great potential in the molecular design of antithrombogenic membranes for use in human blood.


    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...


    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  12. Binding of Bacillus thuringiensis Cry1A toxins with brush border membrane vesicles of maize stem borer (Chilo partellus Swinhoe). (United States)

    Sharma, Priyanka; Nain, Vikrant; Lakhanpaul, Suman; Kumar, P A


    Maize stem borer (Chilo partellus) is a major insect pest of maize and sorghum in Asia and Africa. Bacillus thuringiensis (Bt) δ-endotoxins have been found effective against C. partellus, both in diet-overlay assay and in transgenic plants. Gene stacking as one of the resistance management strategies in Bt maize requires an understanding of receptor sharing and binding affinity of δ-endotoxins. In the present study, binding affinity of three fluorescein isothiocyanate labeled Cry1A toxins showed high correlation with the toxicity of respective δ-endotoxins. Competitive binding studies showed that Cry1Ab toxins share some of the binding sites with Cry1Aa and Cry1Ac with low affinity and that Cry1Ab may have additional binding sites that are unavailable to the other two toxins tested.

  13. Electrospun regenerated cellulose nanofibrous membranes surface-grafted with polymer chains/brushes via the atom transfer radical polymerization method for catalase immobilization. (United States)

    Feng, Quan; Hou, Dayin; Zhao, Yong; Xu, Tao; Menkhaus, Todd J; Fong, Hao


    In this study, an electrospun regenerated cellulose (RC) nanofibrous membrane with fiber diameters of ∼200-400 nm was prepared first; subsequently, 2-hydroxyethyl methacrylate (HEMA), 2-dimethylaminoethyl methacrylate (DMAEMA), and acrylic acid (AA) were selected as the monomers for surface grafting of polymer chains/brushes via the atom transfer radical polymerization (ATRP) method. Thereafter, four nanofibrous membranes (i.e., RC, RC-poly(HEMA), RC-poly(DMAEMA), and RC-poly(AA)) were explored as innovative supports for immobilization of an enzyme of bovine liver catalase (CAT). The amount/capacity, activity, stability, and reusability of immobilized catalase were evaluated, and the kinetic parameters (Vmax and Km) for immobilized and free catalase were determined. The results indicated that the respective amounts/capacities of immobilized catalase on RC-poly(HEMA) and RC-poly(DMAEMA) nanofibrous membranes reached 78 ± 3.5 and 67 ± 2.7 mg g(-1), which were considerably higher than the previously reported values. Meanwhile, compared to that of free CAT (i.e., 18 days), the half-life periods of RC-CAT, RC-poly(HEMA)-CAT, RC-poly(DMAEMA)-CAT, and RC-poly(AA)-CAT were 49, 58, 56, and 60 days, respectively, indicating that the storage stability of immobilized catalase was also significantly improved. Furthermore, the immobilized catalase exhibited substantially higher resistance to temperature variation (tested from 5 to 70 °C) and lower degree of sensitivity to pH value (tested from 4.0 and 10.0) than the free catalase. In particular, according to the kinetic parameters of Vmax and Km, the nanofibrous membranes of RC-poly(HEMA) (i.e., 5102 μmol mg(-1) min(-1) and 44.89 mM) and RC-poly(DMAEMA) (i.e., 4651 μmol mg(-1) min(-1) and 46.98 mM) had the most satisfactory biocompatibility with immobilized catalase. It was therefore concluded that the electrospun RC nanofibrous membranes surface-grafted with 3-dimensional nanolayers of polymer chains/brushes would be

  14. Amnionless function is required for cubilin brush-border expression and intrinsic factor-cobalamin (vitamin B12) absorption in vivo. (United States)

    He, Qianchuan; Madsen, Mette; Kilkenney, Adam; Gregory, Brittany; Christensen, Erik I; Vorum, Henrik; Højrup, Peter; Schäffer, Alejandro A; Kirkness, Ewen F; Tanner, Stephan M; de la Chapelle, Albert; Giger, Urs; Moestrup, Søren K; Fyfe, John C


    Amnionless (AMN) and cubilin gene products appear to be essential functional subunits of an endocytic receptor called cubam. Mutation of either gene causes autosomal recessive Imerslund-Gräsbeck syndrome (I-GS, OMIM no. 261100) in humans, a disorder characterized by selective intestinal malabsorption of cobalamin (vitamin B12) and urinary loss of several specific low-molecular-weight proteins. Vital insight into the molecular pathology of I-GS has been obtained from studies of dogs with a similar syndrome. In this work, we show that I-GS segregates in a large canine kindred due to an in-frame deletion of 33 nucleotides in exon 10 of AMN. In a second, unrelated I-GS kindred, affected dogs exhibit a homozygous substitution in the AMN translation initiation codon. Studies in vivo demonstrated that both mutations abrogate AMN expression and block cubilin processing and targeting to the apical membrane. The essential features of AMN dysfunction observed in vivo are recapitulated in a heterologous cell-transfection system, thus validating the system for analysis of AMN-cubilin interactions. Characterization of canine AMN mutations that cause I-GS establishes the canine model as an ortholog of the human disorder well suited to studies of AMN function and coevolution with cubilin.

  15. Dimeric assembly of enterocyte brush border enzymes

    DEFF Research Database (Denmark)

    Danielsen, E M


    temperature (20 degrees C) reduced the rate of, but did not prevent, dimerization. Maltase-glucoamylase (EC only appeared as a dimer when extracted and analyzed under low salt conditions, suggesting a weak association between the two subunits. This finding is consistent with the electronmicroscopic...

  16. Life at the border: Adaptation of proteins to anisotropic membrane environment (United States)

    Pogozheva, Irina D; Mosberg, Henry I; Lomize, Andrei L


    This review discusses main features of transmembrane (TM) proteins which distinguish them from water-soluble proteins and allow their adaptation to the anisotropic membrane environment. We overview the structural limitations on membrane protein architecture, spatial arrangement of proteins in membranes and their intrinsic hydrophobic thickness, co-translational and post-translational folding and insertion into lipid bilayers, topogenesis, high propensity to form oligomers, and large-scale conformational transitions during membrane insertion and transport function. Special attention is paid to the polarity of TM protein surfaces described by profiles of dipolarity/polarizability and hydrogen-bonding capacity parameters that match polarity of the lipid environment. Analysis of distributions of Trp resides on surfaces of TM proteins from different biological membranes indicates that interfacial membrane regions with preferential accumulation of Trp indole rings correspond to the outer part of the lipid acyl chain region—between double bonds and carbonyl groups of lipids. These “midpolar” regions are not always symmetric in proteins from natural membranes. We also examined the hydrophobic effect that drives insertion of proteins into lipid bilayer and different free energy contributions to TM protein stability, including attractive van der Waals forces and hydrogen bonds, side-chain conformational entropy, the hydrophobic mismatch, membrane deformations, and specific protein–lipid binding. PMID:24947665

  17. Brushes and proteins

    NARCIS (Netherlands)

    Bosker, W.T.E.


      Brushes and Proteins   Wouter T. E. Bosker         Protein adsorption at solid surfaces can be prevented by applying a polymer brush at the surface. A polymer brush consists of polymer chains end-grafted to the surface at such a grafting density that th

  18. The effect of prostaglandin synthase inhibitor, aspirin on the rat intestinal membrane structure and function El efecto del inhibidor de la sintasa de prostaglandina, aspirina, sobre la estructura y función de la membrana intestinal de la rata


    Kaur, G.; J. Kaur; Mittal, N.; S. Nath Sanyal


    Aspirin at a dose of 50 mg/kg body weight was found to decrease the activity of the rat intestinal brush border membrane (BBM) - associated enzymes such as the sucrase, lactase, maltase and alkaline phosphatase. Aspirin treatment also led to a decrease in the microviscosity in the native as well as the benzyl alcohol treated membrane which might be due to the lipid peroxidative damage in the membrane. Physical correlation of the membrane oxidative damage was evident as the Fourier Transformat...

  19. Insulated Fiber Brush. (United States)

    An insulated-strand fiber brush is provided for a DC motor /generator. The brush is comprised of a plurality of fiber segments which are insulated from one another near the contact surface of a rotor bar. In one embodiment, insulating spacers are fixed to a brush assembly and wear with the fibers, and in another embodiment insulation is provided by a separate shell. (Author)

  20. Effect of trichloroethylene (TCE) toxicity on the enzymes of carbohydrate metabolism, brush border membrane and oxidative stress in kidney and other rat tissues. (United States)

    Khan, Sheeba; Priyamvada, Shubha; Khan, Sara A; Khan, Wasim; Farooq, Neelam; Khan, Farah; Yusufi, A N K


    Trichloroethylene (TCE), an industrial solvent, is a major environmental contaminant. Histopathological examinations revealed that TCE caused liver and kidney toxicity and carcinogenicity. However, biochemical mechanism and tissue response to toxic insult are not completely elucidated. We hypothesized that TCE induces oxidative stress to various rat tissues and alters their metabolic functions. Male Wistar rats were given TCE (1000 mg/kg/day) in corn oil orally for 25 d. Blood and tissues were collected and analyzed for various biochemical and enzymatic parameters. TCE administration increased blood urea nitrogen, serum creatinine, cholesterol and alkaline phosphatase but decreased serum glucose, inorganic phosphate and phospholipids indicating kidney and liver toxicity. Activity of hexokinase, lactate dehydrogenase increased in the intestine and liver whereas decreased in renal tissues. Malate dehydrogenase and glucose-6-phosphatase and fructose-1, 6-bisphosphatase decreased in all tissues whereas increased in medulla. Glucose-6-phosphate dehydrogenase increased but NADP-malic enzyme decreased in all tissues except in medulla. The activity of BBM enzymes decreased but renal Na/Pi transport increased. Superoxide dismutase and catalase activities variably declined whereas lipid peroxidation significantly enhanced in all tissues. The present results indicate that TCE caused severe damage to kidney, intestine, liver and brain; altered carbohydrate metabolism and suppressed antioxidant defense system.

  1. Genetic diversity of the Plasmodium falciparum apical membrane antigen I gene in parasite population from the China-Myanmar border area. (United States)

    Zhu, Xiaotong; Zhao, Zhenjun; Feng, Yonghui; Li, Peipei; Liu, Fei; Liu, Jun; Yang, Zhaoqing; Yan, Guiyun; Fan, Qi; Cao, Yaming; Cui, Liwang


    To investigate the genetic diversity of the Plasmodium falciparum apical membrane antigen 1 (PfAMA1) gene in Southeast Asia, we determined PfAMA1 sequences from 135 field isolates collected from the China-Myanmar border area and compared them with 956 publically available PfAMA1 sequences from seven global P. falciparum populations. This analysis revealed high genetic diversity of PfAMA1 in global P. falciparum populations with a total of 229 haplotypes identified. The genetic diversity of PfAMA1 gene from the China-Myanmar border is not evenly distributed in the different domains of this gene. Sequence diversity in PfAMA1 from the China-Myanmar border is lower than that observed in Thai, African and Oceanian populations, but higher than that in the South American population. This appeared to correlate well with the levels of endemicity of different malaria-endemic regions, where hyperendemic regions favor genetic cross of the parasite isolates and generation of higher genetic diversity. Neutrality tests show significant departure from neutrality in the entire ectodomain and Domain I of PfAMA1 in the China-Myanmar border parasite population. We found evidence supporting a substantial continent-wise genetic structure among P. falciparum populations, with the highest genetic differentiation detected between the China-Myanmar border and the South American populations. Whereas no alleles were unique to a specific region, there were considerable geographical differences in major alleles and their frequencies, highlighting further necessity to include more PfAMA1 alleles in vaccine designs.

  2. Cavitation during wire brushing (United States)

    Li, Bo; Zou, Jun; Ji, Chen


    In our daily life, brush is often used to scrub the surface of objects, for example, teeth, pots, shoes, pool, etc. And cleaning rust and stripping paint are accomplished using wire brush. Wire brushes also can be used to clean the teeth for large animals, such as horses, crocodiles. By observing brushing process in water, we capture the cavitation phenomenon on the track of moving brush wire. It shows that the cavitation also can affect the surface. In order to take clear and entire pictures of cavity, a simplified model of one stainless steel wire brushing a boss is adopted in our experiment. A transparent organic tank filled with deionized water is used as a view box. And a high speed video camera is used to record the sequences. In experiment, ambient pressure is atmospheric pressure and deionized water temperature is kept at home temperature. An obvious beautiful flabellate cavity zone appears behind the moving steel wire. The fluctuation of pressure near cavity is recorded by a hydrophone. More movies and pictures are used to show the behaviors of cavitation bubble following a restoring wire. Beautiful tracking cavitation bubble cluster is captured and recorded to show.

  3. Fouling-resistant polymer brush coatings

    KAUST Repository

    Thérien-Aubin, Héloïse


    A major problem to be addressed with thin composite films used in processes such as coatings or water purification is the biofouling of the surface. To address this problem in a model system, functionalized polyaramide membranes containing an atom transfer radical polymerization (ATRP) initiator were synthesized as a versatile approach to easily modify the surface properties of the polyaramide. Poly(methacrylic acid) brushes were grown using surface initiated ATRP followed by the functionalization of the poly(methacrylic acid) brushes with different side-chains chosen to reduce adhesion between the membrane and foulant. The relation between membrane fouling and the physicochemical properties of the surface was investigated in detail. © 2011 Elsevier Ltd. All rights reserved.

  4. Surface grafted polymer brushes: potential applications in dengue biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Baratela, Fernando Jose Costa; Higa, Olga Zazuco, E-mail: [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Faria, Henrique Antonio Mendonca de; Queiroz, Alvaro Antonio Alencar de, E-mail: [Universidade Federal de Itajuba (UNIFEI), Itajuba, MG (Brazil). Instituto de Fisica e Quimica


    A polymer brush membrane-based ultrasensitive biosensor for dengue diagnosis was constructed using poly(hydroxyethyl methacrylate) (PHEMA) brushes immobilized onto low density polyethylene (LDPE) films. LDPE surface films were initially modified by Ar{sup +} ion irradiation to activate the polymer surface. Subsequently, graft polymerization of 2-hydroxyethyl methacrylate onto the activated LDPE surface was carried out under aqueous conditions to create patterned polymer brushes of PHEMA. The grafted PHEMA brushes were characterized by Fourier transform-infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and contact angle analysis. The SEM observations showed that selective surface activation with Ar+ implantation and graft polymerization on the selectively activated surface had occurred. The PHEMA brushes were electrically characterized in the presence of concentrations of human immunoglobulin (IgG). The proposed amperometric biosensor was successfully used for determination of IgG in physiologic samples with excellent responses. (author)

  5. Polymer Brushes as Functional, Patterned Surfaces for Nanobiotechnology. (United States)

    Welch, M Elizabeth; Xu, Youyong; Chen, Hongjun; Smith, Norah; Tague, Michele E; Abruña, Héctor D; Baird, Barbara; Ober, Christopher K


    Polymer brushes have many desirable characteristics such as the ability to tether molecules to a substrate or change the properties of a surface. Patterning of polymer films has been an area of great interest due to the broad range of applications including bio-related and medicinal research. Consequently, we have investigated patterning techniques for polymer brushes which allow for two different functionalities on the same surface. This method has been applied to a biosensor device which requires both polymer brushes and a photosensitizer to be polymerized on a patterned gold substrate. Additionally, the nature of patterned polymer brushes as removable thin films was explored. An etching process has enabled us to lift off very thin membranes for further characterization with the potential of using them as Janus membranes for biological applications.

  6. Functional Coatings with Polymer Brushes


    König, Meike


    The scope of this work is to fathom different possibilities to create functional coatings with polymer brushes. The immobilization of nanoparticles and enzymes is investigated, as well as the affection of their properties by the stimuli-responsiveness of the brushes. Another aspect is the coating of 3D-nanostructures by polymer brushes and the investigation of the resulting functional properties of the hybrid material. The polymer brush coatings are characterized by a variety of microscopic a...

  7. Endobiliary brush biopsy

    DEFF Research Database (Denmark)

    Adamsen, Sven; Olsen, Marianne; Jendresen, Marianne Bille;


    OBJECTIVE: Obtaining cytological specimens by wire-guided endobiliary brushing at the time of endoscopic retrograde cholangiopancreatography (ERCP) is a convenient way to reach a diagnosis. Sensitivity for malignant disease is generally around 50% and specificity around 100%. The present study wa...

  8. Ureteral retrograde brush biopsy (United States)

    ... biopsy URL of this page: // Ureteral retrograde brush biopsy To use ... minutes. A cystoscope is first placed through the urethra into the bladder. Cystoscope is a tube with a ... results may show cancer cells ( carcinoma ). This test is often used to ...

  9. Border markets

    DEFF Research Database (Denmark)

    Walther, Olivier


    The objective of this issue of Articulo – Journal of Urban Research is to examine the characteristics of border markets in a comparative perspective. In this introductory paper, I first discuss what makes African border markets different from other markets, and examine several factors that explain...... their unequal economic development: the presence of a trade community, the combination of trading and productive activities, and the relative porosity of borders. In a second part, I examine how border markets on the U.S.-Mexico border must simultaneously guarantee the security of the state while favoring...... regional trade. The last part of the paper argues that more policy attention should be paid to border markets which, despite being at the margin of states, are a vital component of their economy. Fifty years after most West African states became independent and just as NAFTA turns 20, it is high time...

  10. Pericellular Brush and Mechanics of Guinea Pig Fibroblast Cells Studied with AFM. (United States)

    Dokukin, Maxim; Ablaeva, Yulija; Kalaparthi, Vivekanand; Seluanov, Andrei; Gorbunova, Vera; Sokolov, Igor


    The atomic force microscopy (AFM) indentation method combined with the brush model can be used to separate the mechanical response of the cell body from deformation of the pericellular layer surrounding biological cells. Although self-consistency of the brush model to derive the elastic modulus of the cell body has been demonstrated, the model ability to characterize the pericellular layer has not been explicitly verified. Here we demonstrate it by using enzymatic removal of hyaluronic content of the pericellular brush for guinea pig fibroblast cells. The effect of this removal is clearly seen in the AFM force-separation curves associated with the pericellular brush layer. We further extend the brush model for brushes larger than the height of the AFM probe, which seems to be the case for fibroblast cells. In addition, we demonstrate that an extension of the brush model (i.e., double-brush model) is capable of detecting the hierarchical structure of the pericellular brush, which, for example, may consist of the pericellular coat and the membrane corrugation (microridges and microvilli). It allows us to quantitatively segregate the large soft polysaccharide pericellular coat from a relatively rigid and dense membrane corrugation layer. This was verified by comparison of the parameters of the membrane corrugation layer derived from the force curves collected on untreated cells (when this corrugation membrane part is hidden inside the pericellular brush layer) and on treated cells after the enzymatic removal of the pericellular coat part (when the corrugations are exposed to the AFM probe). We conclude that the brush model is capable of not only measuring the mechanics of the cell body but also the parameters of the pericellular brush layer, including quantitative characterization of the pericellular layer structure.

  11. Biomolecule-functionalized polymer brushes. (United States)

    Jiang, Hui; Xu, Fu-Jian


    Functional polymer brushes have been utilized extensively for the immobilization of biomolecules, which is of crucial importance for the development of biosensors and biotechnology. Recent progress in polymerization methods, in particular surface-initiated atom transfer radical polymerization (ATRP), has provided a unique means for the design and synthesis of new biomolecule-functionalized polymer brushes. This current review summarizes such recent research activities. The different preparation strategies for biomolecule immobilization through polymer brush spacers are described in detail. The functional groups of the polymer brushes used for biomolecule immobilization include epoxide, carboxylic acid, hydroxyl, aldehyde, and amine groups. The recent research activities indicate that functional polymer brushes become versatile and powerful spacers for immobilization of various biomolecules to maximize their functionalities. This review also demonstrates that surface-initiated ATRP is used more frequently than other polymerization methods in the designs of new biomolecule-functionalized polymer brushes.

  12. Water Soluble Responsive Polymer Brushes

    Directory of Open Access Journals (Sweden)

    Andrew J. Parnell


    Full Text Available Responsive polymer brushes possess many interesting properties that enable them to control a range of important interfacial behaviours, including adhesion, wettability, surface adsorption, friction, flow and motility. The ability to design a macromolecular response to a wide variety of external stimuli makes polymer brushes an exciting class of functional materials, and has been made possible by advances in modern controlled polymerization techniques. In this review we discuss the physics of polymer brush response along with a summary of the techniques used in their synthesis. We then review the various stimuli that can be used to switch brush conformation; temperature, solvent quality, pH and ionic strength as well as the relatively new area of electric field actuation We discuss examples of devices that utilise brush conformational change, before highlighting other potential applications of responsive brushes in real world devices.

  13. Why Is Brushing with Toothpaste Important? (United States)

    ... to your desktop! more... Why is Brushing With Toothpaste Important? Article Chapters Why is Brushing With Toothpaste ... mouth with a clean feeling. Is brushing with toothpaste enough to fight cavities and gum disease? No. ...

  14. Bottle-Brush Brushes: Cylindrical Molecular Brushes of Poly(2-oxazoline) on Glassy Carbon

    KAUST Repository

    Zhang, Ning


    We report on the synthesis of brushes of bottle-brushes of poly(2-oxazoline)s on polished glassy carbon (GC) substrates. First, homogeneous and stable poly(2-isopropenyl-2-oxazoline) (PIPOx) brush layers with thicknesses up to 160 nm were created directly onto GC by the self-initiated photografting and photopolymerization (SIPGP) of 2-isopropenyl-2-oxazoline (IPOx). Kinetic studies reveal a linear increase in thickness with the polymerization time. In a second reaction, the pendant 2-oxazoline ring of the PIPOx brushes were used for the living cationic ring-opening polymerization (LCROP) with different substituted 2-oxazoline monomers to form the side chains. Also for the second surface-initiatedLCROPfrom the surface-bound macroinitiator brushes, the thickness increase with the polymerization time was found to be linear and reproducible. Characterization of the resulting bottle-brush brushes by FTIR spectroscopy,contact angle, and AFM indicates a high side chain grafting density and quantitative reactions. Finally, we have demonstrated the possibility of functionalizing the bottle-brush brushes side chain end groups with sterically demanding molecules. © 2009 American Chemical Society.

  15. Cholesterol depletion of enterocytes. Effect on the Golgi complex and apical membrane trafficking

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Niels-Christiansen, L L; Thorsen, Evy


    Intestinal brush border enzymes, including aminopeptidase N and sucrase-isomaltase, are associated with "rafts" (membrane microdomains rich in cholesterol and sphingoglycolipids). To assess the functional role of rafts in the present work, we studied the effect of cholesterol depletion on apical...... membrane trafficking in enterocytes. Cultured mucosal explants of pig small intestine were treated for 2 h with the cholesterol sequestering agent methyl-beta-cyclodextrin and lovastatin, an inhibitor of hydroxymethylglutaryl-coenzyme A reductase. The treatment reduced the cholesterol content >50...

  16. Immunoelectrophoretic studies on pig intestinal brush border proteins

    DEFF Research Database (Denmark)

    Danielsen, Erik Michael; Sjöström, H; Norén, O


    aminopeptidase (EC, aspartate aminopeptidase (EC, dipeptidyl peptidase IV (EC 3.4.14.X), lactase (EC, glucoamylase (EC, sucrase (EC, isomaltase (EC and alkaline phosphatase (EC In addition, at least four faint immunoprecipitates were formed...

  17. Developmental organization of the intestinal brush-border cytoskeleton. (United States)

    Takemura, R; Masaki, T; Hirokawa, N


    At the terminal web of chicken intestinal epithelial cell, the actin bundles are cross-linked by a fine filamentous network of actin-associated cross-linkers. Myosin, fodrin, and TW 260/240 have been identified as major components of the cross-linkers. We studied the development of the cross-linkers by quick-freeze, deep-etch electron microscopy, and the expression of cross-linker proteins (myosin, fodrin 240, and TW 260) by immunofluorescence and immunoblotting analysis during the embryogenesis. Microvilli start to form at 5-7 days, and the rootlets begin to elongate at 10 days. At an early stage of the development of the terminal web (13 days), fodrin 240 and a small amount of myosin are expressed, and a few actin-associated cross-linkers are present between the rootlets. However, TW 260 is not expressed at this stage. At an intermediate stage (19 days), the amount of myosin increases, and TW 260 begins to be expressed. The number of cross-linkers associated with the unit length of the rootlets is 24/microns. At the final stage of the terminal web formation (2 days after hatching), the amount of fodrin 240, myosin, and TW 260 is similar to the adult level, and the number of the actin-associated cross-linkers per unit length of the rootlet is 27/microns (approximately 85% of the adult). These results suggest that the synthesis of cross-linker proteins may be intricately regulated to achieve the desired density of cross-linkages at each developmental stage: at early and intermediate stages, sufficient and not an excess of cross-linkages are formed; and at a final stage, a higher complexity of cross-linkages is achieved. In addition, there is a differential expression of the components of the actin-associated cross-linkers: myosin and fodrin could be early components of the cross-linkers involved in the basic stabilization of the terminal web structure, whereas TW 260/240 becomes incorporated later, possibly involved in the stabilization preparatory to the rapid elongation of microvilli, which occurs after the formation of the terminal web.

  18. Border poetics

    Directory of Open Access Journals (Sweden)

    Liv Lundberg


    Full Text Available The language of poetry is a language of inquiry, not the language of a genre. Poetry has the capacity of entering those zones known as borderlands, where you meet strange things and foreign people. In this poetic world view, the border is not an edge along the fringe of lands, societies and experiences, but rather their very middle – and their in-between. The structures of language are social structures in which meanings and intentions are already in place, always fighting for power and dominance, with rhetorical figures and more violent weapons.

  19. Brush/Fin Thermal Interfaces (United States)

    Knowles, Timothy R.; Seaman, Christopher L.; Ellman, Brett M.


    Brush/fin thermal interfaces are being developed to increase heat-transfer efficiency and thereby enhance the thermal management of orbital replaceable units (ORUs) of electronic and other equipment aboard the International Space Station. Brush/fin thermal interfaces could also be used to increase heat-transfer efficiency in terrestrial electronic and power systems. In a typical application according to conventional practice, a replaceable heat-generating unit includes a mounting surface with black-anodized metal fins that mesh with the matching fins of a heat sink or radiator on which the unit is mounted. The fins do not contact each other, but transfer heat via radiation exchange. A brush/fin interface also includes intermeshing fins, the difference being that the gaps between the fins are filled with brushes made of carbon or other fibers. The fibers span the gap between intermeshed fins, allowing heat transfer by conduction through the fibers. The fibers are attached to the metal surfaces as velvet-like coats in the manner of the carbon fiber brush heat exchangers described in the preceding article. The fiber brushes provide both mechanical compliance and thermal contact, thereby ensuring low contact thermal resistance. A certain amount of force is required to intermesh the fins due to sliding friction of the brush s fiber tips against the fins. This force increases linearly with penetration distance, reaching 1 psi (6.9 kPa) for full 2-in. (5.1 cm) penetration for the conventional radiant fin interface. Removal forces can be greater due to fiber buckling upon reversing the sliding direction. This buckling force can be greatly reduced by biasing the fibers at an angle perpendicularly to the sliding direction. Means of containing potentially harmful carbon fiber debris, which is electrically conductive, have been developed. Small prototype brush/fin thermal interfaces have been tested and found to exhibit temperature drops about onesixth of that of conventional

  20. Ionizable polyelectrolyte brushes: brush height and electrosteric interaction

    NARCIS (Netherlands)

    Biesheuvel, P.M.


    Semi-analytical scaling theory is used to describe quenched and annealed (weakly charged, ionizable, charge-regulating) polyelectrolyte brushes in electrolyte solutions of arbitrary salt concentration. An Alexander-De Gennes box model with homogeneous distribution of polymer segments and the free en

  1. Fabrication of protein-resistant blend based on PVDF-HFP and amphiphilic brush copolymer made from PMMA and PEGMA (United States)

    Hwangbo, Kyung-Hee; Kim, Yu-Jeong; Cho, Kuk Young


    Polymeric blends provide a facile route to obtaining materials with various synergistic properties arising from the individual components. Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), a hydrophobic polymer, is finding new applications in polymer electrolytes, membranes, and heat-resistant structural materials owing to its high thermal stability, mechanical strength, and weatherability. In this report, blends of PVDF-HFP and polymer brush were prepared with enhanced water uptake and protein resistance, which are important requirements for membranes used in food and biological applications. Polymer brush is composed of poly(methyl methacrylate) main chains, which are miscible with PVDF-HFP, and hydrophilic poly(ethylene glycol) (PEG) brush chains. Incorporation of PEG chains through the polymer brush structure not only enhanced water uptake and protein adsorption resistance but also produced a well-distributed morphology of the blending components through the matrix as evidenced by observation of the morphology after selective extraction of polymer brush from the matrix.

  2. Brush Seals for Improved Steam Turbine Performance (United States)

    Turnquist, Norman; Chupp, Ray; Baily, Fred; Burnett, Mark; Rivas, Flor; Bowsher, Aaron; Crudgington, Peter


    GE Energy has retrofitted brush seals into more than 19 operating steam turbines. Brush seals offer superior leakage control compared to labyrinth seals, owing to their compliant nature and ability to maintain very tight clearances to the rotating shaft. Seal designs have been established for steam turbines ranging in size from 12 MW to over 1200 MW, including fossil, nuclear, combined-cycle and industrial applications. Steam turbines present unique design challenges that must be addressed to ensure that the potential performance benefits of brush seals are realized. Brush seals can have important effects on the overall turbine system that must be taken into account to assure reliable operation. Subscale rig tests are instrumental to understanding seal behavior under simulated steam-turbine operating conditions, prior to installing brush seals in the field. This presentation discusses the technical challenges of designing brush seals for steam turbines; subscale testing; performance benefits of brush seals; overall system effects; and field applications.

  3. Nanotribology of charged polymer brushes (United States)

    Klein, Jacob

    Polymers at surfaces, whose modern understanding may be traced back to early work by Sam Edwards1, have become a paradigm for modification of surface properties, both as steric stabilizers and as remarkable boundary lubricants2. Charged polymer brushes are of particular interest, with both technological implications and especially biological relevance where most macromolecules are charged. In the context of biolubrication, relevant in areas from dry eye syndrome to osteoarthritis, charged polymer surface phases and their complexes with other macromolecules may play a central role. The hydration lubrication paradigm, where tenaciously-held yet fluid hydration shells surrounding ions or zwitterions serve as highly-efficient friction-reducing elements, has been invoked to understand the excellent lubrication provided both by ionized3 and by zwitterionic4 brushes. In this talk we describe recent advances in our understanding of the nanotribology of such charged brush systems. We consider interactions between charged end-grafted polymers, and how one may disentangle the steric from the electrostatic surface forces5. We examine the limits of lubrication by ionized brushes, both synthetic and of biological origins, and how highly-hydrated zwitterionic chains may provide extremely effective boundary lubrication6. Finally we describe how the lubrication of articular cartilage in the major joints, a tribosystem presenting some of the greatest challenges and opportunities, may be understood in terms of a supramolecular synergy between charged surface-attached polymers and zwitterionic groups7. Work supported by European Research Council (HydrationLube), Israel Science Foundation (ISF), Petroleum Research Fund of the American Chemical Society, ISF-NSF China Joint Program.

  4. Membraner

    DEFF Research Database (Denmark)

    Bach, Finn


    Notatet giver en kort introduktion til den statiske virkemåde af membraner og membrankonstruktioner......Notatet giver en kort introduktion til den statiske virkemåde af membraner og membrankonstruktioner...

  5. Resisting protein adsorption on biodegradable polyester brushes. (United States)

    Hu, Xinfang; Gorman, Christopher B


    The protein adsorption and degradation behaviors of poly(lactic acid), poly(glycolic acid) (PGA) and poly(ε-caprolactone) (PCL) brushes and their co-polymer brushes with oligo(ethylene glycol) (OEG) were studied. Both brush structure and relative amount of OEG and polyester were found to be important to the protein resistance of the brushes. A protein-resisting surface can be fabricated either by using OEG as the top layer of a copolymer brush or by increasing the amount of OEG relative to polyester when using a hydroxyl terminated OEG (OEG-OH) and a methoxy terminated OEG (OEG-OMe) mixture as the substrate layer. The degradation of single polyester brushes and their co-polymer brushes using OEG-OH as a substrate layer or using OEG as a top layer was hindered. This phenomenon was rationalized by the inhibition of the proposed back-biting process as the hydroxy end groups of polyester were blocked by OEG molecules. Among these brushes tested, PGA co-polymer brushes using the methoxy/hydroxyl OEG mixture as the substrate layer proved to be both protein-resistant and degradable due to the relatively large amount of OEG moieties and the good biodegradability of PGA.

  6. BSA adsorption on bimodal PEO brushes

    NARCIS (Netherlands)

    Bosker, WTE; Iakovlev, PA; Norde, W; Stuart, Martien A. Cohen


    BSA adsorption onto bimodal PEO brushes at a solid surface was measured using optical reflectometry. Bimodal brushes consist of long (N = 770) and short (N = 48) PEO chains and were prepared on PS surfaces, applying mixtures of PS29-PEO48 and PS37-PEO770 block copolymers and using the Langmuir-Blodg

  7. BSA adsorption on bimodal PEO brushes

    NARCIS (Netherlands)

    Bosker, W.T.E.; Iakovlev, P.A.; Norde, W.; Cohen Stuart, M.A.


    BSA adsorption onto bimodal PEO brushes at a solid surface was measured using optical reflectometry. Bimodal brushes consist of long (N=770) and short (N=48) PEO chains and were prepared on PS surfaces, applying mixtures of PS 29-PEO48 and PS37-PEO770 block copolymers and using the Langmuir-Blodgett

  8. Border Crossings (National) (United States)

    Department of Transportation — Border Crossing Ports (NTAD 2015) are points of entry for land modes along the U.S. - Canadian and U.S.- Mexcian borders. The ports of entry are located in 15 states...

  9. Construction of 3D micropatterned surfaces with wormlike and superhydrophilic PEG brushes to detect dysfunctional cells. (United States)

    Hou, Jianwen; Shi, Qiang; Ye, Wei; Fan, Qunfu; Shi, Hengchong; Wong, Shing-Chung; Xu, Xiaodong; Yin, Jinghua


    Detection of dysfunctional and apoptotic cells plays an important role in clinical diagnosis and therapy. To develop a portable and user-friendly platform for dysfunctional and aging cell detection, we present a facile method to construct 3D patterns on the surface of styrene-b-(ethylene-co-butylene)-b-styrene elastomer (SEBS) with poly(ethylene glycol) brushes. Normal red blood cells (RBCs) and lysed RBCs (dysfunctional cells) are used as model cells. The strategy is based on the fact that poly(ethylene glycol) brushes tend to interact with phosphatidylserine, which is in the inner leaflet of normal cell membranes but becomes exposed in abnormal or apoptotic cell membranes. We demonstrate that varied patterned surfaces can be obtained by selectively patterning atom transfer radical polymerization (ATRP) initiators on the SEBS surface via an aqueous-based method and growing PEG brushes through surface-initiated atom transfer radical polymerization. The relatively high initiator density and polymerization temperature facilitate formation of PEG brushes in high density, which gives brushes worm-like morphology and superhydrophilic property; the tendency of dysfunctional cells adhered on the patterned surfaces is completely different from well-defined arrays of normal cells on the patterned surfaces, providing a facile method to detect dysfunctional cells effectively. The PEG-patterned surfaces are also applicable to detect apoptotic HeLa cells. The simplicity and easy handling of the described technique shows the potential application in microdiagnostic devices.

  10. Interfacial Friction and Adhesion of Polymer Brushes

    KAUST Repository

    Landherr, Lucas J. T.


    A bead-probe lateral force microscopy (LFM) technique is used to characterize the interfacial friction and adhesion properties of polymer brushes. Our measurements attempt to relate the physical structure and chemical characteristics of the brush to their properties as thin-film, tethered lubricants. Brushes are synthesized at several chain lengths and surface coverages from polymer chains of polydimethylsiloxane (PDMS), polystyrene (PS), and a poly(propylene glycol)-poly(ethylene glycol) block copolymer (PPG/PEG). At high surface coverage, PDMS brushes manifest friction coefficients (COFs) that are among the lowest recorded for a dry lubricant film (μ ≈ 0.0024) and close to 1 order of magnitude lower than the COF of a bare silicon surface. Brushes synthesized from higher molar mass chains exhibit higher friction forces than those created using lower molar mass polymers. Increased grafting density of chains in the brush significantly reduces the COF by creating a uniform surface of stretched chains with a decreased surface viscosity. Brushes with lower surface tension and interfacial shear stresses manifest the lowest COF. In particular, PDMS chains exhibit COFs lower than PS by a factor of 3.7 and lower than PPG/PEG by a factor of 4.7. A scaling analysis conducted on the surface coverage (δ) in relation to the fraction (ε) of the friction force developing from adhesion predicts a universal relation ε ∼ δ4/3, which is supported by our experimental data. © 2011 American Chemical Society.

  11. Calcium ion transport across plasma membranes isolated from rat kidney cortex. (United States)

    Gmaj, P; Murer, H; Kinne, R


    Basal-lateral-plasma-membrane vesicles and brush-border-membrane vesicles were isolated from rat kidney cortex by differential centrifugation followed by free-flow-electrophoresis. Ca2+ uptake into these vesicles was investigated by a rapid filtration method. Both membranes show a considerable binding of Ca2+ to the vesicle interior, making the analysis of passive fluxes in uptake experiments difficult. Only the basal-lateral-plasma-membrane vesicles exhibit an ATP-dependent pump activity which can be distinguished from the activity in mitochondrial and endoplasmic reticulum by virtue of the different distribution during free-flow electrophoresis and its lack of sensitivity to oligomycin. The basal-lateral plasma membranes contain in addition a Na+/Ca2+-exchange system which mediates a probably rheogenic counter-transport of Ca2+ and Na+ across the basal cell border. The latter system is probably involved in the secondary active Na+-dependent and ouabain-inhibitable Ca2+ reabsorption in the proximal tubule, the ATP-driven system is probably more important for the maintenance of a low concentration of intracellular Ca2+.

  12. Vaccination of sheep against haemonchosis with H11, a gut membrane-derived protective antigen from the adult parasite: prevention of the periparturient rise and colostral transfer of protective immunity. (United States)

    Andrews, S J; Hole, N J; Munn, E A; Rolph, T P


    Pregnant ewes were immunised with a fraction highly enriched in the membrane glycoprotein antigen H11, isolated from the intestinal brush border of adult Haemonchus contortus. Immunity induced by immunisation was able to abolish almost completely (98-99%) the worm egg output from pregnant ewes challenged with ca. 10,000 infective larvae of H. contortus during the last trimester. Furthermore, lambs born and reared on vaccinated ewes had substantial antibody levels to H11 derived from maternal transfer. This antibody conferred moderate protection against a bolus challenge of ca. 3000 infective larvae of H. contortus in 5-week-old lambs.

  13. Touch- and Brush-Spinning of Nanofibers. (United States)

    Tokarev, Alexander; Asheghali, Darya; Griffiths, Ian M; Trotsenko, Oleksandr; Gruzd, Alexey; Lin, Xin; Stone, Howard A; Minko, Sergiy


    Robust, simple, and scalable touch- and brush-spinning methods for the drawing of nanofibers, core-shell nanofibers, and their aligned 2D and 3D meshes using polymer solutions and melts are discussed.

  14. Preparation of gradient polyacrylate brushes in microchannels. (United States)

    Lee, Seongyeol; Youm, Sang Gil; Song, Yeari; Yi, Whikum; Sohn, Daewon


    Gradient poly(2-hydroxyethyl methacrylate) brushes were synthesized by surface-initiated atom transfer radical polymerization (ATRP) confined within a microfluidic system on a silicon wafer. For ATRP, surface initiator, 11-((2-bromo, 2-methyl) propionyloxy) undecyltrichlorosilane (BUC), was synthesized, and allowed to self-assemble in a monolayer on the Si wafer, as analyzed by XPS to confirm the presence of an ester group of BUC. A solution containing 2-hydroxyethylmethacrylate, Cu catalyst, and bipyridin was allowed to flow in a microchannel and polymerize, resulting in the brushes with a gradient of thickness on the Si wafer. Using ellipsometry and ATR-IR, we verified the gradients of well established brushes on the Si wafer. AFM and contact angle data showed that wettability of the brushes did not exhibit a linear relationship with hydrophilicity.

  15. Water driven turbine/brush pipe cleaner (United States)

    Werlink, Rudy J. (Inventor)


    Assemblies are disclosed for cleaning the inside walls of pipes and tubes. A first embodiment includes a small turbine with angled blades axially mounted on one end of a standoff support. An O-ring for stabilizing the assembly within the pipe is mounted in a groove within the outer ring. A replaceable circular brush is fixedly mounted on the opposite end of the standoff support and can be used for cleaning tubes and pipes of various diameters, lengths and configurations. The turbine, standoff support, and brush spin in unison relative to a hub bearing that is fixedly attached to a wire upstream of the assembly. The nonrotating wire is for retaining the assembly in tension and enabling return of the assembly to the pipe entrance. The assembly is initially placed in the pipe or tube to be cleaned. A pressurized water or solution source is provided at a required flow-rate to propel the assembly through the pipe or tube. The upstream water pressure propels and spins the turbine, standoff support and brush. The rotating brush combined with the solution cleans the inside of the pipe. The solution flows out of the other end of the pipe with the brush rotation controlled by the flow-rate. A second embodiment is similar to the first embodiment but instead includes a circular shaped brush with ring backing mounted in the groove of the exterior ring of the turbine, and also reduces the size of the standoff support or eliminates the standoff support.

  16. Borders, Violence, Law

    Directory of Open Access Journals (Sweden)



    Full Text Available This article explores the relationship between violence, law and borders by analyzing both the violence at the borders and the violence of the borders. In both cases, the author states that violence exerted by means of law, as well as migratory and asylum policies, threaten the universal human rights of the most vulnerable people and cannot be seen as exercising the legitimate monopoly of force, resulting in the destruction of the Rule of Law.

  17. Business, brokers and borders

    DEFF Research Database (Denmark)

    Walther, Olivier

    Using social network analysis, this paper studies the structure of trade networks that developed across West African borders. The first part aims to understand the centralization of cross-border trade networks. In a business environment where transaction costs are extremely high, we find that dec......Using social network analysis, this paper studies the structure of trade networks that developed across West African borders. The first part aims to understand the centralization of cross-border trade networks. In a business environment where transaction costs are extremely high, we find...... developed with foreign partners from a different origin, religion or culture. In the second part, we study the spatial structure of trade networks and the influence of national borders on the development of social ties. The paper shows that the spatial form of trade networks is constrained by the historical...

  18. Solvent-induced immiscibility of polymer brushes eliminates dissipation channels

    NARCIS (Netherlands)

    Beer, de S.; Kutnyanszky, E.; Schon, P.M.; Vancso, G.J.; Müser, M.H.


    Polymer brushes lead to small friction and wear and thus hold great potential for industrial applications. However, interdigitation of opposing brushes makes them prone to damage. Here we report molecular dynamics simulations revealing that immiscible brush systems can form slick interfaces, in whic

  19. Brushes and soap : Grafted polymers and their interactions with nanocolloids

    NARCIS (Netherlands)

    Currie, E.P.K.


    Layers of polymer chains end-attached to a grafting plane at high densities, so-called brushes, are a curious state of matter. The (average) monomer density within the brush is as high as in a semi-dilute polymer solution, resulting in a high osmotic pressure in the brush. Due to the grafting, howev

  20. Border cells versus border-like cells: are they alike? (United States)

    Driouich, Azeddine; Durand, Caroline; Cannesan, Marc-Antoine; Percoco, Giuseppe; Vicré-Gibouin, Maité


    Roots of many plants are known to produce large numbers of 'border' cells that play a central role in root protection and the interaction of the root with the rhizosphere. Unlike border cells, border-like cells were described only recently in the model plant Arabidopsis thaliana and other Brassicaceae species and very little is known about the functional properties of border-like cells as compared with 'classical' border cells. To stimulate discussion and future research on this topic, the function of border cells and the way border-like cells are organized, maintained, and possibly involved in plant protection is discussed here.

  1. Scaling Relationships for Spherical Polymer Brushes Revisited. (United States)

    Chen, Guang; Li, Hao; Das, Siddhartha


    In this short paper, we revisit the scaling relationships for spherical polymer brushes (SPBs), i.e., polymer brushes grafted to rigid, spherical particles. Considering that the brushes can be described to be encased in a series of hypothetical spherical blobs, we identify significant physical discrepancies in the model of Daoud and Cotton (Journal of Physics, 1982), which is considered to be the state of the art in scaling modeling of SPBs. We establish that the "brush" configuration of the polymer molecules forming the SPBs is possible only if the swelling ratio (which is the ratio of the end-to-end length of the blob-encased polymer segment to the corresponding coil-like polymer segment) is always less than unity-a notion that has been erroneously overlooked in the model of Daoud and Cotton. We also provide new scaling arguments that (a) establish this swelling (or more appropriately shrinking) ratio as a constant (less than unity) for the case of "good" solvent, (b) recover the scaling predictions for blob dimension and monomer number and monomer concentration distributions within the blob, and

  2. Lubrication at physiological pressures by polyzwitterionic brushes. (United States)

    Chen, Meng; Briscoe, Wuge H; Armes, Steven P; Klein, Jacob


    The very low sliding friction at natural synovial joints, which have friction coefficients of mu lubrication is attributed primarily to the strong hydration of the phosphorylcholine-like monomers that make up the robustly attached brushes, and may have relevance to a wide range of human-made aqueous lubrication situations.

  3. Synthesis and characterization of metal oxide nanorod brushes

    Indian Academy of Sciences (India)

    Kalyan Raidongia; M Eswaramoorthy


    Nanorod brushes of -Al2O3, MoO3 and ZnO have been synthesized using amorphous carbon nanotube (-CNT) brushes as the starting material. The brushes of -Al2O3 and MoO3 are made up of single crystalline nanorods. In the case of ZnO brushes, the nanorod bristles are made by the fusion of 15–25 nm size nanoparticles and are porous in nature. Metal oxide nanorod brushes thus obtained have been characterized by XRD, FESEM, TEM and Raman spectroscopy. Single crystalline ruby nanorods were obtained by introducing chromium ions during the synthesis of alumina rods.

  4. Borders, Risks, Exclusions

    Directory of Open Access Journals (Sweden)

    Benjamin Muller


    Full Text Available In this paper the border is evaluated as a fold of power relations in which sovereign capacity and competence is marshaled in the furtherance of illiberal practices. Drawing from interview data of officials in various agencies engaged in the US-Canada and particularly the Windsor-Detroit corridor, the argument is made that the border is a site for both negative and positive power, for insertion and subtraction, and that surveillance and compliance regimes are ‘run’ not so much in the furtherance of a precautionary or preemptive end-state, but as intermediate values that are sufficiently malleable by an invigorated sovereign, expressed in the residue of discretion in and between the many border agencies.

  5. Border region studies

    DEFF Research Database (Denmark)

    Makkonen, Teemu; Williams, Allan


    The contemporary conditions of academic capitalism exert pressures on researchers to avoid ‘peripheral’ journals and ‘unfashionable’ topics. Here an attempt is made to shed light onto the structure of one such ‘offbeat’ field, namely ‘border region studies’, by discussing its geographical...... distribution, key themes, significance and impact. The review suggests that border region studies can be considered a significant and important ‘branch’ of regional studies, which accounts for a small but increasing proportion of regional studies research particularly in Europe and North America. Four main...

  6. Transparent Aluminium Oxide Coatings of Polymer Brushes. (United States)

    Micciulla, Samantha; Duan, XiaoFei; Strebe, Julia; Löhmann, Oliver; Lamb, Robert N; von Klitzing, Regine


    A novel method for the preparation of transparent Al2O3 coatings of polymers is presented. An environmental-friendly sol-gel method is employed, which implies mild conditions and low costs. A thermoresponsive brush is chosen as a model surface. X-ray photoelectron spectroscopy is used to characterize the samples during the conversion of the precursor Al(OH)3 into oxide and to prove the mildness of the protocol. The study evidences a relation between lateral homogeneity of alumina and the wettability of the polymer surface by the precursor solution, while morphology and elasticity are dominated by the polymer properties. The study of the swelling behavior of the underneath brush reveals the absence of water uptake, proving the impermeability of the alumina layer. The broad chemical and structural variety of polymers, combined with the robustness of transparent alumina films, makes these composites promising as biomedical implants, protective sheets and components for electric and optical devices.

  7. Dynamic Polymer Brush at Polymer/Water Interface (United States)

    Yokoyama, Hideaki; Inoue, Kazuma; Ito, Kohzo; Inutsuka, Manabu; Tanaka, Keiji; Yamada, Norifumi


    A layer of polymer chains tethered by one end to a surface is called polymer brush and known to show various unique properties such as anti-fouling. The surface segregation phenomena of copolymers with surface-active blocks should be useful for preparing such a brush layer in spontaneous process. We report hydrophilic polymer brushes formed at the interface between water and polymer by the segregation of amphiphilic diblock copolymers blended in a crosslinked rubbery matrix and call it ``dynamic polymer brush.'' In this system, the hydrophilic block with high surface energy avoids air surface, but segregates to cover the interface between hydrophobic elastomer and water. The structures of the brush layers at D2O/polymer interfaces were measured by neutron reflectivity. The dynamic polymer brush layer surprisingly reached 75% of the contour length of the chain and 2.7 chains/nm2. The brush density was surprisingly comparable to the polymer brush fabricated by the ``grafting-from'' method. We will discuss the dependence of the brush structure on molecular weight and block fraction of amphiphilic block copolymers. Such a surprisingly thick and dense polymer brush were induced by the large enthalpy gain of hydration of hydrophilic block.

  8. Novel Hyperbranched Polyurethane Brushes for Biomedical Applications

    Institute of Scientific and Technical Information of China (English)

    Ton; Loontjens; Bart; Plum


    1 Results The objective was to make hyperbranched (HB) polyurethane brushes with reactive end groups, to coat biomedical devices and to enable the introduction of various functionalities that are needed to fulfill biomedical tasks.Biomedical materials should fulfill at least three requirements: (1) good mechanical properties, (2) good biocompatibility and (3) provided with functionalities to perform the required tasks. Since polyurethanes are able to fulfill the first 2 requirements we focused in this w...

  9. Metastatic urachal carcinoma in bronchial brush cytology

    Directory of Open Access Journals (Sweden)

    Fatima Zahra Aly


    Full Text Available Urachal carcinoma is rare comprising less than 1% of all bladder carcinomas. Metastases of urachal carcinoma have been reported to meninges, brain, ovary, lung, and maxilla. Cytologic features of metastatic urachal carcinoma have not been previously reported. We present a case of metastatic urachal adenocarcinoma in bronchial brushings and review the use of immunohistochemistry in its diagnosis. A 47-year-old female was seen initially in 2007 with adenocarcinoma of the bladder dome for which she underwent partial cystectomy. She presented in 2011 with a left lung mass and mediastinal adenopathy. Bronchoscopy showed an endobronchial lesion from which brushings were obtained. These showed numerous groups of columnar cells with medium sized nuclei and abundant cytoplasm. The cells were positive for CK20 and CDX2 and negative for CK7. The cytomorphological findings were similar to those in the previous resection specimen and concurrent biopsy. This is the first case report of bronchial brushings containing metastatic urachal carcinoma. No specific immunohistochemical profile is available for its diagnosis. The consideration of a second primary was a distinct possibility in this case due to the lapse of time from primary resection, absence of local disease, and lack of regional metastases.

  10. From Borders to Margins

    DEFF Research Database (Denmark)

    Parker, Noel


    upon Deleuze's philosophy to set out an ontology in which the continual reformulation of entities in play in ‘post-international' society can be grasped.  This entails a strategic shift from speaking about the ‘borders' between sovereign states to referring instead to the ‘margins' between a plethora...

  11. Borders of Discourse?

    DEFF Research Database (Denmark)

    Hermansen, Janni Berthou


    This article aims to discuss a fundamentally different approach to discourse analysis by using a pragmatic point of departure for understanding use of language. Using an empirical example from a construction project it is discussed how material as well as societal dimensions of collaboration...... functions as borders for transformations of discourse – and these dimensions are most often intertwined...

  12. Biometric Borders and Counterterrorism (United States)


    34Transforming Travel and Border Controls: Checkpoints in the Open Society," Government Information Quarterly 22, no. 4 (01 October 2005), 594-625, http...the Open Society." Government Information Quarterly 22, no. 4 (1 October 2005): 594– 625. Hsu, Spencer S. "U.S. Preparing to Drop Tracking of

  13. Canada and Mexico Border Crossings (United States)

    Department of Homeland Security — Border Crossing Ports are points of entry for land modes along the U.S. - Canadian and U.S.- Mexcian borders. The ports of entry are located in 15 states along the...

  14. Superhydrophilic Polyelectrolyte Brush Layers with Imparted Anti-Icing Properties

    DEFF Research Database (Denmark)

    Chernyy, Sergey; Järn, Mikael; Shimizu, Kyoko;


    This work demonstrates the feasibility of superhydrophilic polyelectrolyte brush coatings for anti-icing applications. Five different types of ionic and nonionic polymer brush coatings of 25-100 nm thickness were formed on glass substrates using silane chemistry for surface premodification followed......(-), SO4(2-), and C12SO3(-) ions. By consecutive measurements of the strength of ice adhesion toward ion-incorporated polymer brushes on glass it was found that Li(+) ions reduce ice adhesion by 40% at -18 °C and 70% at -10 °C. Ag(+) ions reduce ice adhesion by 80% at -10 °C relative to unmodified glass....... In general, superhydrophilic polyelectrolyte brushes exhibit better anti-icing property at -10 °C compared to partially hydrophobic brushes such as poly(methyl methacrylate) and surfactant exchanged polyelectrolyte brushes. The data are interpreted using the concept of a quasi liquid layer (QLL...

  15. An interdisciplinary approach to valuing water from brush control


    Lemberg, B.; Mjelde, J.; Conner, J; Griffin, R.; Rosenthal, W; Stuth, J


    Metadata only record This paper develops an integrated model to assess the viability of increasing water yields in the Frio River basin of Texas through brush control. The presented method accounts for the effect of brush control on forage productivity and water supply by incorporating ecological, hydrologic, and economic models. The simulation of water yields suggests that brush control would increase water yields on 35% of the land area, but the costs usually would exceed the financial b...

  16. Mechanisms for nano particle removal in brush scrubber cleaning (United States)

    Huang, Yating; Guo, Dan; Lu, Xinchun; Luo, Jianbin


    A model describing the nano particle (cleaning is presented based on experiment results and theoretical analysis. The forces on the particles in different situations are analyzed and discussed. The adhesion forces of the van der Waals force, the electrostatic force, the brush load and the static friction between the particle and the wafer are calculated. The contact elastic force, hydrodynamic drag force and friction between the brush and the particle are considered as removal forces and are evaluated. The porous structure and roughness surface of brush material are considered in the hydrodynamic model to describe the brush deformation and the flow field in the cleaning process. The porous structure will result in decrease of hydrodynamic drag force. There are four situations of the particles relative to the brush roughness asperities for which the forces on the particle are different. When the particle is in contact with a brush asperity or on the wafer surface and in a semi-infinite fluid flow field, the particle may be removed by hydrodynamic force and elastic force in the presence of surfactant. When the particle is embedded in the brush asperity, the remove will realized when the friction caused by adhesion between the brush and the particle overcome the adhesion force between particle and wafer surface. The removed particles will be in the flow field or adhered on the brush surface and may redeposit on the wafer surface.

  17. Morphological transformations in polymer brushes in binary mixtures: DPD study. (United States)

    Cheng, Jianli; Vishnyakov, Aleksey; Neimark, Alexander V


    Morphological transformations in polymer brushes in a binary mixture of good and bad solvents are studied using dissipative particle dynamics simulations drawing on a characteristic example of polyisoprene natural rubber in an acetone-benzene mixture. A coarse-grained DPD model of this system is built based on the experimental data in the literature. We focus on the transformation of dense, collapsed brush in bad solvent (acetone) to expanded brush solvated in good solvent (benzene) as the concentration of benzene increases. Compared to a sharp globule-to-coil transition observed in individual tethered chains, the collapsed-to-expanded transformation in brushes is found to be gradual without a prominent transition point. The transformation becomes more leveled as the brush density increases. At low densities, the collapsed brush is highly inhomogeneous and patterned into bunches composed of neighboring chains due to favorable polymer-polymer interaction. At high densities, the brush is expanded even in bad solvent due to steric restrictions. In addition, we considered a model system similar to the PINR-acetone-benzene system, but with the interactions between the solvent components worsened to the limit of miscibility. Enhanced contrast between good and bad solvents facilitates absorption of the good solvent by the brush, shifting the collapsed-to-expanded transformation to lower concentrations of good solvent. This effect is especially pronounced for higher brush densities.

  18. Entanglements of End Grafted Polymer Brushes in a Polymeric Matrix (United States)

    Grest, Gary S.; Hoy, Robert S.


    The entanglement of a polymer brush immersed in a melt of mobile polymer chains is studied by molecular dynamics simulations. A primitive path analysis (PPA) is carried out to identify the brush/brush, brush/melt and melt/melt entanglements as a function of distance from the substrate. The PPA characterizes the microscopic state of conformations of the polymer chain and is ideally suited to identify chain/chain entanglements. We use a new thin-chain PPA technique to eliminate spurious non-entangled inter chain contacts arising from excluded volume. As the grafting density of the brush increases we find that the entanglements of the brush with the melt decrease as the system crosses over from the wet to dry brush regime. Results are compared to brush/brush entanglements in an implicit solvent of varying solvent quality. Sandia is a multiprogram laboratory operated by Sandia Corp., a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  19. Alterations in gut microflora populations and brush border functionality following intra-amniotic daidzein administration (United States)

    Daidzein is an isoflavone found primarily in soybean and various soy-based products such as tofu. In the intestines, daidzein is reductively transformed to its constituent metabolites equol and O-desmethylangolensin. Although the ingestion of daidzein has been associated with marked physiological im...

  20. Comparison of two pig intestinal brush border peptidases with the corresponding renal enzymes

    DEFF Research Database (Denmark)

    Norén, O; Sjöström, H; Danielsen, Erik Michael;


    -glutamyl-transferase was found to be identical to that of the kidney enzyme. The electrophoretic mobilities of dipeptidyl peptidase IV from the two organs differed greatly. The difference was almost abolished by treatment with neuraminidase, suggesting that the variation in mobility was due to different contents of sialic acid......Intestinal dipeptidyl peptidase IV and gamma-glutamyltransferase were compared to the corresponding kidney enzymes with respect to immunological and electrophoretic properties. The influences of selected effectors on the two enzymes were also studied. The two kidney peptidases exhibited...... the reaction of total identity with the corresponding intestinal enzymes in immunodiffusion. Furthermore, the intestinal dipeptidyl peptidase IV and gamma-glutamyl transferase showed the same inhibition patterns as the corresponding kidney enzymes and the acceptor specificity of the intestinal gamma...

  1. Straddling the border

    DEFF Research Database (Denmark)

    Eilenberg, Michael


    of confrontation between divergent political ideologies. In the majority of the Southeast Asian borderlands, this implied violent disruption in the lives of local borderlanders that came to affect their relationship to their nation-state. A case in point is the ethnic Iban population living along the international...... border between the Indonesian province of West Kalimantan and the Malaysian state of Sarawak on the island of Borneo. Based on local narratives, the aim of this paper is to unravel the little known history of how the Iban segment of the border population in West Kalimantan became entangled in the highly...... militarized international disputes with neighbouring Malaysia in the early 1960s, and in subsequent military co-operative ‘anti-communist’ ‘counter-insurgency’ efforts by the two states in the late 1960–1970s. This paper brings together facets of national belonging and citizenship within a borderland context...

  2. Stretching the Border

    DEFF Research Database (Denmark)

    Horstmann, Alexander


    In this paper, I hope to add a complementary perspective to James Scott’s recent work on avoidance strategies of subaltern mountain people by focusing on what I call the refugee public. The educated Karen elite uses the space of exile in the Thai borderland to reconstitute resources and to re-ent......-based organizations succeed to stretch the border by establishing a firm presence that is supported by the international humanitarian economy in the refugee camps in Northwestern Thailand....

  3. Metrics for border management systems.

    Energy Technology Data Exchange (ETDEWEB)

    Duggan, Ruth Ann


    There are as many unique and disparate manifestations of border systems as there are borders to protect. Border Security is a highly complex system analysis problem with global, regional, national, sector, and border element dimensions for land, water, and air domains. The complexity increases with the multiple, and sometimes conflicting, missions for regulating the flow of people and goods across borders, while securing them for national security. These systems include frontier border surveillance, immigration management and customs functions that must operate in a variety of weather, terrain, operational conditions, cultural constraints, and geopolitical contexts. As part of a Laboratory Directed Research and Development Project 08-684 (Year 1), the team developed a reference framework to decompose this complex system into international/regional, national, and border elements levels covering customs, immigration, and border policing functions. This generalized architecture is relevant to both domestic and international borders. As part of year two of this project (09-1204), the team determined relevant relative measures to better understand border management performance. This paper describes those relative metrics and how they can be used to improve border management systems.

  4. Effect of Frequency of Brushing Teeth on Plaque and Calculus Accumulation, and Gingivitis in Dogs. (United States)

    Harvey, Colin; Serfilippi, Laurie; Barnvos, Donald


    The efficacy of brushing the teeth of beagle dogs in a randomized, controlled, blinded study design using a clearly-defined brushing technique was evaluated for 4 brushing frequencies: brushing daily, brushing every other day, brushing weekly and brushing every other week, compared with no brushing in a control group of dogs. All dogs were fed a standard dry kibble diet during the study. Standard plaque, calculus, and gingivitis indices were used to score the teeth. A 'clean tooth' model was used. No gingival or non-gingival lacerations or other signs of injury to oral tissues were found at the end of the 28 day trial period. Brushing more frequently had greater effectiveness in retarding accumulation of plaque and calculus, and reducing the severity of pre-existing gingivitis. Brushing daily or every other day produced statistically significant improved results compared with brushing weekly or every other week. Based on the results of this study, daily brushing is recommended.

  5. Efficacy of oral brush cytology in the evaluation of the oral premalignant and malignant lesions


    Babshet, M; Nandimath, K; S K Pervatikar; V G Naikmasur


    Objective: In the present study, oral brush cytology of premalignant and malignant lesions was performed using tooth brush. The cytopathological diagnosis of brush cytology was compared with that of punch biopsy. The reliability of oral brush cytology using tooth brush was assessed in terms of sensitivity and specificity. Materials and Methods: A total of 67 patients, 32 premalignant lesions and other 35 frank oral carcinomas, were included in the study. All patients underwent oral brush ...

  6. Effect of entomocidal proteins from Bacillus thuringiensis on ion permeability of apical membranes of Tenebrio molitor larvae gut epithelium. (United States)

    Andreev, I M; Bulushova, N V; Zalunin, I A; Chestukhina, G G


    Effects of entomocidal Cry-type proteins, delta-endotoxins Cry3A and Cry11A produced by Bacillus thuringiensis, on ion permeability of the apical membranes of intestinal epithelium from Tenebrio molitor larvae midgut were studied. Using potential-sensitive dyes safranine O and oxonol VI and DeltapH indicator acridine orange, it was shown that placing brush border membrane vesicles (BBMV) (loaded with Mg2+ during their preparation) into a salt-free buffer medium resulted in spontaneous generation of transmembrane electric potential on the vesicular membrane (negative inside the vesicles) accompanied by acidification of the aqueous phase inside the vesicles. The generation of transmembrane ion gradients on the vesicular membrane was a result of an electrogenic efflux of Mg2+ from the vesicles as shown by abolishing of the membrane potential by such agents as MgSO4 or CaCl2 in centimolar concentrations, a highly lipophilic cation tetraphenylphosphonium, and some blockers of cell membrane Ca2+-channels in submillimolar concentrations. A passive generation of membrane potential on the vesicular membrane (but positive inside the vesicles) was also observed upon addition of centimolar concentrations of K2SO4. Addition of delta-endotoxins Cry3A and Cry11A to the vesicle suspension in a salt-free buffer medium or in the same medium supplemented with centimolar concentrations of K2SO4 exerted a pronounced hyperpolarization of the vesicular membrane. This hyperpolarization was sensitive to the same agents, which abolished the membrane potential generation in the absence of delta-endotoxin. It is concluded that Cry proteins induced in BBMV from T. molitor opening pores or ion channels, which were considerably more permeable for alkaline- and alkaline-earth metal cations than for the accompanying anions.

  7. 75 FR 39706 - Natural Bristle Paint Brushes From China (United States)


    ... the antidumping duty order on natural bristle paint brushes from China (75 FR 21347, April 23, 2010... revoke the order on June 16, 2010 (75 FR 34097). In light of these developments, the Commission is... COMMISSION Natural Bristle Paint Brushes From China AGENCY: United States International Trade...

  8. 16 CFR Figure 9 to Part 1610 - Brushing Device Template (United States)


    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Brushing Device Template 9 Figure 9 to Part 1610 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE FLAMMABILITY OF CLOTHING TEXTILES Pt.1610, Fig. 9 Figure 9 to Part 1610—Brushing...

  9. 16 CFR Figure 8 to Part 1610 - Brush (United States)


    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Brush 8 Figure 8 to Part 1610 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE FLAMMABILITY OF CLOTHING TEXTILES Pt.1610, Fig. 8 Figure 8 to Part 1610—Brush ER25MR08.007...

  10. 16 CFR Figure 7 to Part 1610 - Brushing Device (United States)


    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Brushing Device 7 Figure 7 to Part 1610 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE FLAMMABILITY OF CLOTHING TEXTILES Pt.1610, Fig. 7 Figure 7 to Part 1610—Brushing Device ER25MR08.006...

  11. Carbazole functionalized isocyanide brushes in heterojunction photovoltaic devices

    NARCIS (Netherlands)

    Lim, E.; Gao, F.; Schwartz, E.; Cornelissen, J.J.L.M.; Nolte, R.J.M.; Rowan, A.E.; Greenham, N.C.; Do, L.M.


    In this work, carbazole-containing polyisocyanide (PIACz) brushes were used for photovoltaic devices. A photovoltaic device was fabricated on top of the brushes by spin-coating a suitable acceptor and evaporating an Al cathode. Devices with a poly(N-vinylcarbazole) (PVK) bulk polymer were also prepa

  12. Brush seal shaft wear resistant coatings (United States)

    Howe, Harold


    Brush seals suffer from high wear, which reduces their effectiveness. This work sought to reduce brush seal wear by identifying and testing several industry standard coatings. One of the coatings was developed for this work. It was a co-sprayed PSZ with boron-nitride added for a high temperature dry lubricant. Other coatings tested were a PSZ, chrome carbide and a bare rotor. Testing of these coatings included thermal shocking, tensile testing and wear/coefficient of friction testing. Wear testing consisted of applying a coating to a rotor and then running a sample tuft of SiC ceramic fiber against the coating. Surface speeds at point of contact were slightly over 1000 ft/sec. Rotor wear was noted, as well as coefficient of friction data. Results from the testing indicates that the oxide ceramic coatings cannot withstand the given set of conditions. Carbide coatings will not work because of the need for a metallic binder, which oxidizes in the high heat produced by friction. All work indicated a need for a coating that has a lubricant contained within itself and the coating must be resistant to an oxidizing environment.

  13. Atmospheric Science Without Borders (United States)

    Panday, Arnico; Praveen, Ps; Adhikary, Bhupesh; Bhave, Prakash; Surapipith, Vanisa; Pradhan, Bidya; Karki, Anita; Ghimire, Shreta; Thapa, Alpha; Shrestha, Sujan


    The Indo-Gangetic Plains (IGP) in northern South Asia are among the most polluted and most densely populated places in the world, and they are upwind of vulnerable ecosystems in the Himalaya mountains. They are also fragmented across 5 countries between which movement of people, data, instruments and scientific understanding have been very limited. ICIMOD's Atmosphere Initiative has for the past three years been working on filling data gaps in the region, while facilitating collaborations across borders. It has established several atmospheric observatories at low and mid elevations in Bhutan and Nepal that provide new data on the inflow of pollutants from the IGP towards the mountains, as well as quantify the effects of local emissions on air quality in mountain cities. EGU will be the first international conference where these data will be presented. ICIMOD is in the process of setting up data servers through which data from the region will be shared with scientists and the general public across borders. Meanwhile, to promote cross-border collaboration among scientists in the region, while addressing an atmospheric phenomenon that affects the lives of the several hundred million people, ICIMOD' Atmosphere Initiative has been coordinating an interdisciplinary multi-year study of persistent winter fog over the Indo-Gangetic Plains, with participation by researchers from Pakistan, India, China, Nepal, Bhutan and Bangladesh. Using a combination of in-situ measurements and sample collection, remote sensing, modeling and community based research, the researchers are studying how changing moisture availability and air pollution have led to increases in fog frequency and duration, as well as the fog's impacts on local communities and energy demand that may affect air pollution emissions. Preliminary results of the Winter 2015-2016 field campaign will be shown.

  14. Virtual hairy brush for digital painting and calligraphy

    Institute of Scientific and Technical Information of China (English)

    XU Songhua; Lau Francis C. M.; XU Congfu; PAN Yunhe


    The design of user friendly and expressive virtual brush systems for interactive digital painting and calligraphy has attracted a lot of attention and effort in both computer graphics and human-computer interaction circles for a long time. Providing a digital environment for paper-less artwork creation is not only challenging in terms of algorithmic design, but also promising for its potential market values. This paper proposes a novel algorithmic framework for interactive digital painting and calligraphy based a novel virtual hairy brush model. The algorithms in the kernel of our simulation framework are built upon solid modeling techniques. Implementing the algorithms, we have developed a virtual hairy brush prototype system with which end users can interactively produce high-quality digital paintings and calligraphic artwork. (The latest progress of our virtual brush project is reported at the website "".)

  15. Cardiology without borders

    Institute of Scientific and Technical Information of China (English)

    Michael Wolk


    @@ Cardiovascular disease takes place in a border-free world. The challenge at the American College of Cardiology (ACC) and anywhere else in the world is to hold patient care above the artificial barriers raised by geopolitical issues. Fundamentally, the goal of ACC members or of any cardiology societies in the world is to provide excellent patient care. Cardiovascular disease is essentially the same throughout the world. Where there are minor variations among individuals, as clinicians we find priceless opportunity to learn. Expanding- rather contracting -our experience base helps us as individuals to realize our best potential as practitioners.

  16. Cross border relationships

    DEFF Research Database (Denmark)

    Singla, Rashmi; Sriram, Sujata


    -being of not just the migrant population, but also the host communities. These relationships represent the microcosm of societal and cultural integration and cohesion at the broader levels. Studies of how and how well migrants, especially youth handle migration indicate transformations in paradigms as both...... in which they were born. These movements also imply human relationships across the borders in different contexts with various cultural, psychological consequences. Relationships of members of migrant groups with each other, and also with the host community have important implications on the health and well...

  17. Collaborating Across Borders (United States)

    Flatten, Amy

    Physicists transcend national boundaries, ethnic differences, and scientific disciplines to address globally shared problems and questions. This talk will highlight how scientists have collaborated across borders - both geographic and scientific - to achieve ground-breaking discoveries through international scientific cooperation. The speaker also will address how international collaborations will be even more crucial for addressing future challenges faced by the physics community, such as building large-scale research facilities, strengthening scientific capacity in developing countries, fostering ''science for diplomacy'' in times of political tensions and other critical issues.

  18. Business, brokers and borders

    DEFF Research Database (Denmark)

    Walther, Olivier


    in two border regions between Niger, Nigeria, and Benin. In a business environment where transaction costs are extremely high, we find that decentralized networks are well adapted to the various uncertainties induced by long-distance trade. We also find that long-distance trade relies both on the trust...... and cooperation shared among local traders, and on the distant ties developed with foreign partners from a different origin, religion or culture. Studying the spatial structure of trade networks, we find that in those markets where trade is recent and where most of the traders are not native of the region...

  19. Potential applications of oral brush cytology with liquid-based technology: results from a cohort of normal oral mucosa. (United States)

    Kujan, Omar; Desai, Mina; Sargent, Alexandra; Bailey, Andrew; Turner, Andrew; Sloan, Philip


    Fifty healthy volunteers were studied to assess the potential applications of oral brush sampling using liquid-based cytology. Three specimens from the buccal mucosa and lateral border of tongue were collected from each subject by using cervical brushes and brooms. The brush was immersed in a preservative fluid. The sample in the preservative fluid was processed according to the manufacturer's directions (SurePath, UK). Slides were stained by the Papanicolaou method and assessed for squamous cell adequacy by the same criteria used for cervical cytology screening. Immunocytochemical staining for FHIT (Fragile Histidine Triad) was applied in liquid-based preparations following the streptavidin-biotin-peroxidase method. Human papillomavirus (HPV) detection was performed using the Hybrid Capture 2 assay (Digene) and the PCR-based Roche AMPLICOR HPV Test. LBC preparation slides showed good sample preservation, specimen adequacy and visualization of cell morphology. Interestingly, nine cases showed borderline cytological abnormalities from apparently normal oral mucosa. All cases showed good quality positive FHIT immunoreactivity staining. All studied cases were high-risk HPV negative using HC2 assay method. However, the AMPLICOR Roche Test detected four samples with positive results for high-risk HPVs. Liquid-based cytology has potential as a screening tool for oral cancer and precancer. The method may also have applications for research and practice in the field of oral cancer and precancer. However a special custom-designed oral cytobrush is required.

  20. Border Security: Barriers Along the U.S. International Border (United States)


    Cabeza Prieta National Wildlife Refuge, and the Buenos Aires National Wildlife Refuge can all be found adjacent to the border. The southwest border...Refuge, Kofa National Wildlife Refuge, and Cabeza Prieta National Wildlife Refuge (all in Arizona) as components of the National Wilderness

  1. Nanoparticle organization in sandwiched polymer brushes. (United States)

    Curk, Tine; Martinez-Veracoechea, Francisco J; Frenkel, Daan; Dobnikar, Jure


    The organization of nanoparticles inside grafted polymer layers is governed by the interplay of polymer-induced entropic interactions and the action of externally applied fields. Earlier work had shown that strong external forces can drive the formation of colloidal structures in polymer brushes. Here we show that external fields are not essential to obtain such colloidal patterns: we report Monte Carlo and molecular dynamics simulations that demonstrate that ordered structures can be achieved by compressing a "sandwich" of two grafted polymer layers, or by squeezing a coated nanotube, with nanoparticles in between. We show that the pattern formation can be efficiently controlled by the applied pressure, while the characteristic length-scale, that is, the typical width of the patterns, is sensitive to the length of the polymers. Based on the results of the simulations, we derive an approximate equation of state for nanosandwiches.

  2. Comprehensive physical rehabilitation after injury brush

    Directory of Open Access Journals (Sweden)

    Kovalenko M.I.


    Full Text Available The influence of physical rehabilitation for patients after recovery efficiency injured hand. The study enrolled 36 patients after a hand injury, which was carried out surgery. Among patients were dominated women 66% and men 34% aged 25 to 50 years. To evaluate the effectiveness of rehabilitation programs used protractor Richter, centimeter tape, hand dynamometer, MHQ questionnaire and system of integral evaluation function brush. Survey of patients conducted at the clinical stage of rehabilitation for two weeks and before surgery. The efficiency effects of passive therapeutic exercises, massage and lymph drainage design for a hand operated device ARTROMOT-F. It is noted that physical rehabilitation for two weeks has greatly improved hand functions. Established to improve results core group of control by 21.8%, poor performance of the control group higher by 10.1% of the principal of, indicating the efficacy of the program.

  3. Quantifying Fluctuations/Correlations in Polymer Brushes (United States)

    Wang, Qiang; Zhang, Xinghua; Zhang, Pengfei; Li, Baohui


    Fast lattice Monte Carlo (FLMC) simulations with multiple occupancy of lattice sites and Kronecker δ -function interactions give orders of magnitude faster/better sampling of the configurational space of multi-chain systems than conventional lattice MC simulations with self- and mutual- avoiding walks and nearest-neighbor interactions. Using FLMC simulations with Wang-Landau -- Transition-Matrix sampling, we have studied polymer brushes in both an implicit and explicit solvent. The various quantities obtained from simulations (including the internal energy, Helmholtz free energy, constant-volume heat capacity, segmental distribution, and chain sizes) are compared with predictions from the corresponding lattice self-consistent field theory and Gaussian fluctuation theory that are based on the same Hamiltonian as in FLMC simulations (thus without any parameter-fitting) to unambiguously and quantitatively reveal the effects of system fluctuations and correlations neglected or treated only approximately in the theories. Q. Wang, Soft Matter, 5, 4564 (2009).

  4. A norbornene polymer brush for electro-optic applications

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Yue; Spring, Andrew M.; Yu, Feng; Yamamoto, Kazuhiro [Institute for Materials Chemistry and Engineering, Kyushu University, 6–1 Kasuga Fukuoka 816–8580 (Japan); Aoki, Isao; Otomo, Akira [National Institute of Information and Communications Technology, 588–2 Iwaoka, Nishi-ku, Kobe 651–2492 (Japan); Yokoyama, Shiyoshi, E-mail: [Institute for Materials Chemistry and Engineering, Kyushu University, 6–1 Kasuga Fukuoka 816–8580 (Japan)


    Norbornene-dicarboximide derived polymer brushes containing Disperse Red 1 appended chromophores have been prepared by sequencial ring opening metathesis polymerization and atom transfer radical polymerization. This brush was then employed as an electro-optic polymer host for high molecular hyperpolarizability phenyl vinylene thiophene vinylene (FTC) bridge chromophores in a binary chromophore system. The r{sub 33} of the polymer brush/bi-chromophore network was evaluated via in situ poling and was measured as 94 pm/V compared to the benchmark polymethylmethacrylate (PMMA) system of 76 pm/V with an identical chromophore. Furthermore, our polymer brush/bi-chromophore network exhibited an enhanced poling efficiency of 1.37 (nm/V){sup 2} as compared to a simple PMMA - FTC host - guest 0.70 (nm/V){sup 2}. - Highlights: • Synthesis of a norbornene polymer brush. • Use of this polymer brush as a host for electro-optic materials. • The polymer brush enables a large electro-optic coefficient r{sub 33}.

  5. Preparation of carbon brushes with thermosetting resin binder

    Institute of Scientific and Technical Information of China (English)


    Carbon brushes with a resin binder were prepared according to an industrial process and the effects of the molding pressure, grains size and cure temperature on the properties of brush samples were discussed. The results show that the bulk density,bending strength and Rockwell hardness increase, while resistivity decreases with increasing molding pressure. Cure temperature has much more influence on the properties of brushes than molding pressure and grains size. Isothermal differential scanning calorimetry(DSC) was used to estimate the degree of cure of resin binder and a novel method of using the true density to measure the degree of cure of resin binder was presented and discussed briefly. Based on optimal process parameters carbon brushes were manufactured, durability tests for brushes were carried out on an alternate current motor and scanning electron microscope(SEM)was adopted to observe the morphology of worn surface of brushes. The results show that a luster oxide film can be formed on the surface of brushes and their service life reaches 380 h.

  6. Brushing abrasion of luting cements under neutral and acidic conditions. (United States)

    Buchalla, W; Attin, T; Hellwig, E


    Four resin based materials (Compolute Aplicap, ESPE; Variolink Ultra, Vivadent; C&B Metabond, Parkell and Panavia 21, Kuraray), two carboxylate cements (Poly-F Plus, Dentsply DeTrey and Durelon Maxicap, ESPE), two glass-ionomer cements (Fuji I, GC and Ketac-Cem Aplicap, ESPE), one resin-modified glass ionomer cement (Vitremer, 3M) one polyacid-modified resin composite (Dyract Cem, Dentsply DeTrey) and one zinc phosphate cement (Harvard, Richter & Hoffmann) were investigated according to their brushing resistance after storage in neutral and acidic buffer solutions. For this purpose 24 cylindrical acrylic molds were each filled with the materials. After hardening, the samples were stored for seven days in 100% relative humidity and at 37 degrees C. Subsequently, they were ground flat and polished. Then each specimen was covered with an adhesive tape leaving a 4 mm wide window on the cement surface. Twelve samples of each material were stored for 24 hours in a buffer solution with a pH of 6.8. The remaining 12 samples were placed in a buffer with a pH of 3.0. All specimens were then subjected to a three media brushing abrasion (2,000 strokes) in an automatic brushing machine. Storage and brushing were performed three times. After 6,000 brushing strokes per specimen, the tape was removed. Brushing abrasion was measured with a computerized laser profilometer and statistically analyzed with ANOVA and Tukey's Standardized Range Test (p < or = 0.05). The highest brushing abrasion was found for the two carboxylate cements. The lowest brushing abrasion was found for one resin based material, Compolute Aplicap. With the exception of three resin-based materials, a lower pH led to a higher brushing abrasion.

  7. Borders in Library

    Directory of Open Access Journals (Sweden)

    N. Toshmakova


    Full Text Available Libraries are fundamental institutions for the life under socialism in Bulgaria (1944-1989. They provide studies and readings for big part of society. This is time when television was very rare in Bulgarian homes and the newspapers were totally controlled by Communist party. This way a library served as the main source of information. Seemingly ordinary cultural centers, they become a powerful tool in the hands of the communist state. They are the ones who are actively worked to impose new socialist thinking trough setting limits on access to readers and therefore control the flow of information. The aim of this article is to trace the influence of restricted by communist censorship institution Glavlit literature. Or to put it another way – what was the role of censorship in the process of establishment of borders created by prohibited access to scientific information.

  8. Antimicrobial penetration in a dual-species oral biofilm after noncontact brushing : an in vitro study

    NARCIS (Netherlands)

    He, Y.; Peterson, B. W.; Ren, Y.; van der Mei, H. C.; Busscher, H. J.


    Oral biofilm is inevitably left behind, even after powered brushing. As a special feature, powered brushing removes biofilm in a noncontact mode. When the brushing distance becomes too large, biofilm is left behind. We hypothesize that biofilm left behind after brushing has different viscoelastic pr

  9. Na+/D-glucose cotransporter based bilayer lipid membrane sensor for D-glucose. (United States)

    Sugao, N; Sugawara, M; Minami, H; Uto, M; Umezawa, Y


    A new type of amperometric blosensor for glucose was fabricated using a Na+/D-glucose cotransporter as the signal-transducing sensory element that exploits the D-glucose-triggered Na+ ion current through bilayer lipid membranes (BLMs). The planar BLM was formed by the folding method across a small aperture of a thin Teflon film. The Na+/D-glucose cotransporter, isolated and purified from small intestinal brush border membrane of guinea pigs, was embedded into BLMs through proteoliposomes. The number of the protein molecules thus incorporated in the present sensing membrane was estimated to be ca. 10(7). The sensor response was measured as an ionic current through the BLM arising from cotransported Na+ ion flux under a constant applied potential and was only induced by D-glucose above 10(-9) M, but not by the other monosaccharides except for D-galactose. The effect of applied potentials, Na+ and K+ ion concentrations, and the addition of a competitive inhibitor, phlorizin, were scrutinized to characterize the sensor output. The results were briefly discussed in terms of the potential use of the Na+/D-glucose cotransporter as a sensory element for D-glucose.

  10. Border mythology: Turner and modernity

    Directory of Open Access Journals (Sweden)

    Jorge E. Brenna B.


    Full Text Available Modernity has been creating spaces, new boundaries and borders, as metaphysical, mythological and symbolic marks of physical and imaginary territories. Modern space and its borders are metaphors, boundaries that are created, walls that rise to identify with some and categorize others. In this short paper we want to approach the problem of the transformation of the idea of border (geographical, cultural, symbolic, etc., for a reflection on the transformations of that civilized obsession called border. The border has always been a reference in facing the identities, names, symbols, different imaginary: it is more confrontational line between two otherness. From the previous framework, we reflect on Turnerian mythology, as we believe that behind the creation of the imagination of the northern border is the mythical vision of the American frontier as ideological canon that explains and confirms the presence of the white race in a border re–made in the image and likeness of the “American Dream”. Frederick Turner’s reflection on the role of the frontier in American history is not only the study of the importance of progress towards the West but –even more so, is the analysis of meaning that had the American frontier as a historical process that ended in 1893, as Turner said, but rather extended into the twentieth century and continues to constantly shaping the process of territorialization of the border.

  11. Brushes and soap : Grafted polymers and their interactions with nanocolloids


    Currie, E.P.K.


    Layers of polymer chains end-attached to a grafting plane at high densities, so-called brushes, are a curious state of matter. The (average) monomer density within the brush is as high as in a semi-dilute polymer solution, resulting in a high osmotic pressure in the brush. Due to the grafting, however, this isotropic osmotic pressure results in an anisotropic stretching of the chains normal to the surface. This degree of stretching can be quite extensive; in this thesis PEO-chains of 700 mono...

  12. Geographical, Sociological and Metaphysical Borders

    Directory of Open Access Journals (Sweden)

    Jacinto Choza Armenta


    Full Text Available During the different ages of history and prehistory, borders have possessed different kinds of natures. Sometimes they did not exist, at other times they have been very diffuse, while at others they have been impassable. There were no borders in the Paleolithic age, or during Greece’s Heroic Age. It was not until the creation of the city-states and the empires that borders began to be consolidated. Territorial demarcations were not very strict during the Middle Ages, either. It was in the modern age that borders acquired an impassable nature, following the birth of the modern State, and they began to weaken with the crisis of the modern State that began in the 20th century. Thus, the author claims, the construction of borders is not a fundamentally political-administrative event. Instead, it seems to be primarily a phenomenon of a cultural nature and, more specifically, of a metaphysical nature.

  13. Virtual instrument for monitoring process of brush plating

    Institute of Scientific and Technical Information of China (English)

    JING Xue-dong; XU Bin-shi; WANG Cheng-tao; ZHU Sheng; DONG Shi-yun


    A virtual instrument(Ⅵ) was developed to monitor the technological parameters in the process of brush plating, including coating thickness, brush-plating current, current density, deposition rate, and brush plating voltage. Meanwhile two approaches were presented to improve the measurement accuracy of coating thickness. One of them aims at eliminating the random interferences by moving average filtering; while the other manages to calculate the quantity of electricity consumed accurately with rectangular integration. With these two approaches, the coating thickness can be measured in real time with higher accuracy than the voltage-frequency conversion method. During the process of plating all the technological parameters are displayed visually on the front panel of the Ⅵ. Once brush current or current density overruns the limited values, or when the coating thickness reaches the objective value, the virtual will alarm. With this Ⅵ, the solution consumption can be decreased and the operating efficiency is improved.

  14. Electroosmotic Flow in Mixed Polymer Brush-Grafted Nanochannels

    Directory of Open Access Journals (Sweden)

    Qianqian Cao


    Full Text Available Mixed polymer brush-grafted nanochannels—where two distinct species of polymers are alternately grafted on the inner surface of nanochannels—are an interesting class of nanostructured hybrid materials. By using a coarse-grained molecular dynamics simulation method, we are able to simulate the electrokinetic transport dynamics of the fluid in such nanochannels as well as the conformational behaviors of the mixed polymer brush. We find that (1 the brush adopts vertically-layered and longitudinally-separated structures due to the coupling of electroosmotic flow (EOF and applied electric field; (2 the solvent quality affects the brush conformations and the transport properties of the EOF; (3 the EOF flux non-monotonically depends on the grafting density, although the EOF velocity in the central region of the channel monotonically depends on the grafting density.

  15. Solid Phase Synthesis of Polymacromer and Copolymacromer Brushes (United States)


    REPORT Solid Phase Synthesis of Polymacromer and Copolymacromer Brushes 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: We report a novel solid phase...form poly-macromer brushes wherein macromonomers are linked via triazole groups. After each addition step, the terminal alkyne group can be deprotected...Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS Solid Phase Synthesis , polymers and copolymers Hernán R. Rengifo, Cristian Grigoras, Benjamin I

  16. Brush development for underwater ship hull coating maintenance (United States)

    Tribou, Melissa Eileen

    Ship hull grooming has been proposed as an environmentally friendly method of maintaining ship hull coatings in a fouling-free condition. It is defined as the frequent and gentle cleaning of a ship hull coating to prevent the establishment of fouling. This research investigated the grooming tool properties and operational requirements needed to implement the method. The grooming tool needs to provide sufficient force to remove incipient fouling without damaging the surface and consume minimal energy. Research showed that a vertical rotating brush design containing brushes filled with angled polypropylene bristles provided an effective method. This brush system was able to successfully prevent incipient fouling from becoming established on a copper ablative and two silicone fouling release coatings when groomed on a weekly basis; however, biofilm was not completely controlled. Brush design and operational parameters in relation to brush normal forces were investigated and models were developed to understand the relationship between bristle stiffness, dimensions, and angular velocity. A preliminary look at wear found that bristle stiffness has an effect on the degree of marring of the surface of a silicone fouling release coating. The knowledge gained by this research may be used to optimize grooming brush design and operational parameters that can be applied to the design and deployment of low power autonomous underwater vehicles that will groom the ship while in port.

  17. Polyelectrolyte brushes in mixed ionic medium studied via intermolecular forces (United States)

    Farina, Robert; Laugel, Nicolas; Pincus, Philip; Tirrell, Matthew


    The vast uses and applications of polyelectrolyte brushes make them an attractive field of research especially with the growing interest in responsive materials. Polymers which respond via changes in temperature, pH, and ionic strength are increasingly being used for applications in drug delivery, chemical gating, etc. When polyelectrolyte brushes are found in either nature (e.g., surfaces of cartilage and mammalian lung interiors) or commercially (e.g., skin care products, shampoo, and surfaces of medical devices) they are always surrounded by mixed ionic medium. This makes the study of these brushes in varying ionic environments extremely relevant for both current and future potential applications. The polyelectrolyte brushes in this work are diblock co-polymers of poly-styrene sulfonate (N=420) and poly-t-butyl styrene (N=20) which tethers to a hydrophobic surface allowing for a purely thermodynamic study of the polyelectrolyte chains. Intermolecular forces between two brushes are measured using the SFA. As multi-valent concentrations are increased, the brushes collapse internally and form strong adhesion between one another after contact (properties not seen in a purely mono-valent environment).

  18. Rotordynamic and leakage characteristics of a 4-stage brush seal (United States)

    Conner, K. J.; Childs, D. W.


    Experimental results are presented for the direct and cross-coupled stiffness and damping coefficients as well as the leakage performance for a 4-stage brush seal. Variable test parameters include the inlet pressure, pressure ratio, shaft speed, fluid prerotation, and seal spacing. Direct damping is shown to increase with running speed; otherwise, the rotordynamic coefficients are relatively insensitive to changes in the test parameters. Cross-coupled stiffness is generally unchanged by increasing the inlet tangential velocity to the seals, suggesting that the brush seal is not affected by inlet swirl. Direct stiffness is shown to increase with frequency; however, the magnitudes of direct stiffness are always positive. Cross-coupled stiffness increases slightly with frequency; yet not as drastically as direct stiffness. Comparisons of test results for the 4-stage brush seal with an 8-cavity labyrinth showed superior rotordynamics performance for the brush seal; viz., large values for direct stiffness and lower values for the (destabilizing) cross-coupled stiffness coefficient. The damping for brush seals is smaller, but comparable to labyrinth seals. The whirl-frequency ratio is always smaller for the brush seal.

  19. Distance, Borders, and Time

    DEFF Research Database (Denmark)

    Skillicorn, David; Walther, Olivier; Zheng, Quan

    This paper explores the spatial and temporal diffusion of political violence in North and West Africa. It does so by endeavoring to represent the mental landscape that lives in the back of a group leader’s mind as he contemplates strategic targeting. We assume that this representation is a combin......This paper explores the spatial and temporal diffusion of political violence in North and West Africa. It does so by endeavoring to represent the mental landscape that lives in the back of a group leader’s mind as he contemplates strategic targeting. We assume that this representation...... constrains a group leader to attack at a location other than the one that would seem to yield the greatest overt payoff. By its very nature, the research problem defies the collection of a full set of structural data. Instead, we leverage functional data from the Armed Conflict Location and Event Data......” of North and West Africa that depicts the permeability to violence. A better understanding of how location, time, and borders condition attacks enables planning, prepositioning, and response....

  20. Firemen without borders

    CERN Multimedia


    Fire knows no borders and neither should the tools for fighting it. It was with this aim in mind that delegates from 14 different countries came to CERN at the beginning of April to take part in the twentieth of a series of twice-yearly international conferences organised by the Federation of European Union Fire Officer Associations (FEU). This latest conference allowed participants to keep abreast of new developments with a view to improving the safety techniques used in their own countries. The first in the series was held in Tampere, Finland, in 1994. The FEU network's objective is to harmonise safety policies and modernise the fire-fighting programme. In particular, it aims to develop an international system for testing hotels' fire alarm systems and to improve language learning in all countries' fire-fighting services. "We want authorities throughout Europe to be aware of the importance of a good joint fire-prevention policy in order to avoid catastrophes such as the fire that destroyed Madrid's Winds...

  1. Crossing borders via mental bridges

    DEFF Research Database (Denmark)

    Keil, Dirk

    The project studies cross-border regional integration in Europe drawing on the example of the emerging Danish-German Femern Belt Region. It focuses on cross-border networking within public administration as part of regional integra- tion. My central question is how national-cultural differences...... influence coopera- tion, coordination and collaboration in administrative cross-border networks. In this connection the project asks after the perception of regional integration seen from the different national backgrounds. The research concentrates on the group of decision makers within the field of public...

  2. Penetration of a Single Domain of Bacillus thuringiensis Cry1Ie-Domain I to a Lipid Membrane In vitro

    Institute of Scientific and Technical Information of China (English)

    GUO Shu-yuan; LI Jie; CHEN Zhen; HE Kang-lai


    Domain I of the activated Crystal protein from Bacillus thuringiensis has a sevenα-helix bundle structure, which is responsible for membrane channel formation in its insecticidal mechanism. Cry1Ie is toxic to Asian corn borer, Ostrinia furnacalis (Guenée), and plays important roles in insect biological control. The domain I from Cry1Ie has been expressed and puriifed in its normal conformation, as embedded in the full length homologous toxin structure. The membrane insertion ability of this single domain was compared with the full length homologous toxin using a monolayer insertion experiment. The results indicated that the Cry1Ie-domain I had the ability to insert into the lipid monolayer, and this ability is greater than that of the IE648 toxin. However, the state of insertion is not stable and remains for only a short period of time. The Cry1Ie-domain I plays no role in receptor binding as it had a nonspeciifc binding with the brush border membrane vesicles of the Asian corn borer.

  3. Effects of Geometry on Leakage Flow Characteristics of Brush Seal

    Institute of Scientific and Technical Information of China (English)

    Yuan Wei; Zhaobo Chen∗; Yinghou Jiao


    In order to better application of brush seal in rotating machinery, the leakage flow characteristics of the brush seal considering geometry effects are numerically analyzed using Reynolds⁃Averaged Navier⁃Stokes ( RANS) model coupling with a non⁃Darcian porous medium model. The reliability of the present numerical method is proved, which is in agreement with the experimental and numerical results from literatures. Three different bristle pack thicknesses, fence heights and initial clearances under different pressure ratios, rotational velocities and other operating conditions are utilized to investigate the effects of geometry modification on the brush seal leakage flow behaviors. It discusses the effectiveness of various geometry configurations outlining important flow features. The results indicate that the increase of fence height and clearance would lead to the increase of leakage rate. But the leakage is not linearly with respect to the bristle pack thickness, and the effect of rotational velocity is not obvious. Moreover, the detailed leakage flow fields and pressure distributions along the rotor surface, free bristle height, and fence height of the brush seals are also presented. The static pressure drop amplitude through the bristle pack and the pressure rise amplitude through the cavity would increase while the pressure differential increases. And the axial pressure is the main reason of bristle blow down. The results provide theoretical support for the brush seal structure optimal design.

  4. Protein adsorption in polyelectrolyte brush type cation-exchangers. (United States)

    Khalaf, Rushd; Coquebert de Neuville, Bertrand; Morbidelli, Massimo


    Ion exchange chromatography materials functionalized with polyelectrolyte brushes (PEB) are becoming an integral part of many protein purification steps. Adsorption onto these materials is different than that onto traditional materials, due to the 3D partitioning of proteins into the polyelectrolyte brushes. Despite this mechanistic difference, many works have described the chromatographic behavior of proteins on polyelectrolyte brush type ion exchangers with much of the same methods as used for traditional materials. In this work, unconventional chromatographic behavior on polyelectrolyte brush type materials is observed for several proteins: the peaks shapes reveal first anti-Langmuirian and then Langmuirian types of interactions, with increasing injection volumes. An experimental and model based description of these materials is carried out in order to explain this behavior. The reason for this behavior is shown to be the 3D partitioning of proteins into the polyelectrolyte brushes: proteins that fully and readily utilize the 3D structure of the PEB phase during adsorption show this behavior, whereas those that do not show traditional ion exchange behavior.

  5. A Nanosecond Pulsed Plasma Brush for Surface Decontamination (United States)

    Neuber, Johanna; Malik, Muhammad; Song, Shutong; Jiang, Chunqi


    This work optimizes a non-thermal, atmospheric pressure plasma brush for surface decontamination. The generated plasma plumes with a maximum length of 2 cm are arranged in a 5 cm long, brush-like array. The plasma was generated in ambient air with plasma chamber at a rate varying between 1 to 7 SLPM. Optimization of the cold plasma brush for surface decontamination was tested in a study of the plasma inactivation of two common pathogens, Staphylococcus aureus and Acinetobacter baumannii. Laminate surfaces inoculated with over-night cultured bacteria were subject to the plasma treatment for varying water concentrations in He, flow rates and discharge voltages. It was found that increasing the water content of the feed gas greatly enhanced the bactericidal effect. Emission spectroscopy was performed to identify the reactive plasma species that contribute to this variation. Additional affiliation: Frank Reidy Research Center for Bioelectrics

  6. Nonstate Actors and the Open Border Policy: The Border Security Case Study of Nepal and India (United States)


    addressing political and social issues.10 Due to the current environment and the ability to move freely along the Nepalese- Indian border, the Nepalese...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited NONSTATE ACTORS...border, 15. NUMBER OF resti-icted border, border patJ·ol, ct-ime, economy, U.S.-Mexican border relations, border secm-ity force, PAGES Nepalese- Indian

  7. Study on Technology and Properties of Brush Plating Coatings

    Institute of Scientific and Technical Information of China (English)

    DI Ping


    A new brush plating process with a soluble anode of nickel was introduced. TDY112 brush plating solution was used on the No.20 carbon steel substrate. It has the higher deposit velocity, better properties and lower cost. Scanning electronic microscopy(SEM), optical microscope, microhardness test and wear test were adopted to detect the surface quality and the properties of the coating, such as micrograph, microstructure, micro-hardness wear resistance and adherence between the coating and the substrate. The experimental results showed that the suitable technological parameters to be used, the coatings had better the surface quality, higher hardness and wear resistance.

  8. Border Security: Barriers Along the U.S. International Border (United States)


    Congressional Research Service ˜ The Library of Congress CRS Report for Congress Received through the CRS Web Order Code RL33659 Border Security...Presidencia,” May 12, 2005. Translation by CRS. Available at [ pagina =31]. Last

  9. Stimuli-Responsive Polyelectrolyte Brushes As a Matrix for the Attachment of Gold Nanoparticles: The Effect of Brush Thickness on Particle Distribution

    Directory of Open Access Journals (Sweden)

    Stephanie Christau


    Full Text Available The effect of brush thickness on the loading of gold nanoparticles (AuNPs within stimuli-responsive poly-(N,N-(dimethylamino ethyl methacrylate (PDMAEMA polyelectrolyte brushes is reported. Atom transfer radical polymerization (ATRP was used to grow polymer brushes via a “grafting from” approach. The brush thickness was tuned by varying the polymerization time. Using a new type of sealed reactor, thick brushes were synthesized. A systematic study was performed by varying a single parameter (brush thickness, while keeping all other parameters constant. AuNPs of 13 nm in diameter were attached by incubation. X-ray reflectivity, electron scanning microscopy and ellipsometry were used to study the particle loading, particle distribution and interpenetration of the particles within the brush matrix. A model for the structure of the brush/particle hybrids was derived. The particle number densities of attached AuNPs depend on the brush thickness, as do the optical properties of the hybrids. An increasing particle number density was found for increasing brush thickness, due to an increased surface roughness.

  10. Enhanced stability of low fouling zwitterionic polymer brushes in seawater with diblock architecture

    NARCIS (Netherlands)

    Quintana, Robert; Gosa, Maria; Janczewski, Dominik; Kutnyanszky, Edit; Vancso, G. Julius


    The successful implementation of zwitterionic polymeric brushes as antifouling materials for marine applications is conditioned by the stability of the polymer chain and the brush-anchoring segment in seawater. Here we demonstrate that robust, antifouling, hydrophilic polysulfobetaine-based brushes

  11. Cross-border innovation cooperation

    DEFF Research Database (Denmark)

    Hjaltadóttir, Rannveig Edda; Makkonen, Teemu; Sørensen, Nils Karl


    Finding a suitable partner is paramount for the success of innovation cooperation. Thus, this paper sets out to analyse the determinants of cross-border innovation cooperation in Denmark focusing on partner selection. The aim of the article is to investigate determinants of partner selection taki...... of choosing a foreign partner while the decision between foreign partners from different locations is not. The results do however not provide support for the theory of knowledge bases influencing the location of innovation partners....... the location of the partners into account. In particular, the discussion is tied to the notion of varying knowledge bases firms utilize in their innovation creation processes. Firm level data from the 2010 Community Innovation Survey in Denmark was used to analyse cross-border innovation cooperation patterns...... of cross-border innovation cooperation. Accordingly, geographical proximity to international borders is found to have a significant, positive effect on choosing partners within EU. The multivariate probit model shows that the decision of choosing a domestic innovation partner is independent of the choice...

  12. Border governance in Mozambique : The intersection of international border controls, regional integration and cross-border regions

    NARCIS (Netherlands)

    F.L.M. Seda (Fulgêncio)


    markdownabstractA tension exists between the interests of states in protecting national security through border controls and those of communities in cross-border regions, to whom frequent border crossing is part of daily life – a necessary part of achieving their own wellbeing. The interplay between

  13. Nonwettable Thin Films from Hybrid Polymer Brushes can be Hydrophilic (United States)


    2006 Hybrid brushes composed of two liquid polymers, poly(dimethylsiloxane) (PDMS) and a highly branched ethoxylated polyethylenimine (EPEI), were...liquid polymers, poly(dimethylsiloxane) (PDMS) and a highly branched ethoxylated polyethylenimine (EPEI; Figure 1). We demonstrate here that hybrid... ethoxylated (highly branched, symmetrical polymer; about 80% of the primary and secondary amines are ethoxylated ), 37% solution in water (EPEI Mw

  14. Charge regulation and local dielectric function in planar polyelectrolyte brushes. (United States)

    Kumar, Rajeev; Sumpter, Bobby G; Kilbey, S Michael


    Understanding the effect of inhomogeneity on the charge regulation and dielectric properties, and how it depends on the conformational characteristics of the macromolecules is a long-standing problem. In order to address this problem, we have developed a field-theory to study charge regulation and local dielectric function in planar polyelectrolyte brushes. The theory is used to study a polyacid brush, which is comprised of chains end-grafted at the solid-fluid interface, in equilibrium with a bulk solution containing monovalent salt ions, solvent molecules, and pH controlling acid. In particular, we focus on the effects of the concentration of added salt and pH of the bulk in determining the local charge and dielectric function. Our theoretical investigations reveal that the dipole moment of the ion-pairs formed as a result of counterion adsorption on the chain backbones play a key role in affecting the local dielectric function. For polyelectrolytes made of monomers having dipole moments lower than the solvent molecules, dielectric decrement is predicted inside the brush region. However, the formation of ion-pairs (due to adsorption of counterions coming from the dissociation of added salt) more polar than the solvent molecules is shown to increase the magnitude of the dielectric function with respect to its bulk value. Furthermore, an increase in the bulk salt concentration is shown to increase the local charge inside the brush region.

  15. Organic monolayers and fluoropolymer brushes : functionalization, stability and tribology

    NARCIS (Netherlands)

    Bhairamadgi, N.S.


    This thesis deals with the adhesion and friction properties of densely grafted and covalently bound fluoropolymer brushes on silicon surfaces with varying thickness and fluorine content. A novel surface-functionalizing method is described using the thiol-yne click (TYC) reaction. The TYC reaction is

  16. Modeling the structure of a polydisperse polymer brush

    NARCIS (Netherlands)

    Vos, de W.M.; Leermakers, F.A.M.


    Numerical self-consistent field theory is used to study the structural characteristics of a polydisperse polymer brush. We consider the relevant case of a Schulz–Zimm distribution and find that even a small degree of polydispersity completely destroys the parabolic density profile. The first moment

  17. Badger hair in shaving brushes comes from protected Eurasian badgers

    NARCIS (Netherlands)

    Domingo-Roura, X.; Marmi, J.; Ferrando, A.; López-Giráldez, F.; Macdonald, D.W.; Jansman, H.A.H.


    The Eurasian badger (Meles meles) is included in Appendix III of the Bern Convention and protected by national laws in many European countries. Badger hair is used to manufacture luxury shaving brushes, although it is frequently argued that the hog badger (Arctonyx collaris), which in Europe is an i

  18. Multifocal Rhizopus microsporus lung infection following brush clearing

    Directory of Open Access Journals (Sweden)

    Artsiom V. Tsyrkunou


    Full Text Available We report a case of pulmonary Rhizopus microsporus infection in a patient with untreated diabetes following brush clearing. The patient was successfully treated with a combined medical and surgical approach with complete resolution of the lung lesions and remains asymptomatic at 11-month follow-up.


    An analytical methodology utilizing models from three disciplines is developed to assess the viability of brush control for wate yield in the Frio River Basin, TX. Ecological, hydrologic, and economic models are used to portray changes in forage production and water supply result...

  20. Formation of surface-attached microstructured polyelectrolyte brushes

    Institute of Scientific and Technical Information of China (English)

    Hai Ning Zhang


    Surface-attached micropatterned polyelectrolyte brushes on planar solid surfaces are generated using free radical polymerization photo-initiated by self-assembled initiator monolayers. It is shown that the formed patterns can be either negative or positive with different patterning processes.

  1. Border Crossing/Entry Data - Boarder Crossing (United States)

    Department of Transportation — Border Crossing/Entry Data provides summary statistics for incoming crossings at the U.S.-Canadian and the U.S.-Mexican border at the port level. Data are available...

  2. Hydrologic Effects of Brush Management in Central Texas (United States)

    Banta, J. R.; Slattery, R.


    Encroachment of woody vegetation into traditional savanna grassland ecosystems in central Texas has largely been attributed to land use practices of settlers, most notably overgrazing and fire suppression. Implementing brush management practices (removing the woody vegetation and allowing native grasses to reestablish in the area), could potentially change the hydrology in a watershed. The U.S. Geological Survey, in cooperation with several local, State, and Federal cooperators, studied the hydrologic effects of ashe juniper (Juniperus ashei) removal as a brush management conservation practice in the Honey Creek State Natural Area in Comal County, Tex. Two adjacent watersheds of 104 and 159 hectares were used in a paired study. Rainfall, streamflow, evapotranspiration (Bowen ratio method), and water quality data were collected in both watersheds. Using a hydrologic mass balance approach, rainfall was allocated to surface-water runoff, evapotranspiration, and groundwater recharge. Groundwater recharge was not directly measured, but estimated as the residual of the hydrologic mass balance. After hydrologic data were collected in both watersheds for 3 years, approximately 80 percent of the woody vegetation (ashe juniper) was selectively removed from the 159 hectare watershed (treatment watershed). Brush management was not implemented in the other (reference) watershed. Hydrologic data were collected in both watersheds for six years after brush management implementation. The resulting data were examined for differences in the hydrologic budget between the reference and treatment watersheds as well as between pre- and post-brush management periods to assess effects of the treatment. Preliminary results indicate there are differences in the hydrologic budget as well as water quality between the watersheds during pre- and post-treatment periods.

  3. Design optimization of a brush turbine with a cleaner/water based solution (United States)

    Kim, Rhyn H.


    Recently, a turbine-brush was analyzed based on the energy conservation and the force momentum equation with an empirical relationship of the drag coefficient. An equation was derived to predict the rotational speed of the turbine-brush in terms of the blade angle, number of blades, rest of geometries of the turbine-brush and the incoming velocity. Using the observed flow conditions, drag coefficients were determined. Based on the experimental values as boundary conditions, the turbine-brush flows were numerically simulated to understand first the nature of the flows, and to extend the observed drag coefficient to a flow without holding the turbine-brush.

  4. Comparison of bronchial brushing and sputum in detection of pediatric pulmonary tuberculosis. (United States)

    Chen, Qiao-Pei; Ren, Shi-Feng; Wang, Xin-Feng; Wang, Mao-Shui


    The retrospective study aimed to evaluate the diagnostic value of bronchial brushing and sputum using acid fast bacilli smear, mycobacterial culture and real-time PCR in detection of pediatric pulmonary tuberculosis, sensitivity and specificity of bronchial brushing and sputum examined by the three methods were calculated and compared to each other. Data showed there were no significant difference in sensitivity between bronchial brushing and matched sputum using each method. But the specificity of real-time PCR on bronchial brushing was lower than on sputum. Compared with bronchial brushing, sputum was better specimen in detection of pediatric pulmonary tuberculosis.

  5. The impact of Border policy effect on cross-border ethnic areas (United States)

    Bie, Q. L.; Zhou, S. Y.; Li, C. S.


    Boundary effect analysis is related to border policy making in the cross-border ethnic area. The border effect literatures show that geographic boundaries have obvious impacts on economic, social and cultural relations in both sides of a nation border. Particularly in cross-border ethnic areas, each ethnic group has strong internal spatial structure relevance, and the boundary effect is more obvious. However, most of China's border areas are cross-border ethnic areas, each of border issues is unique. Under this perspective, we analyze the border effects of various boundaries can provide basis for formulating border management policies. For small scale of cross-border ethnic minority areas, how to formulate the boundary management policy is a good question to explore. This paper is demonstrated by a study of the impact of border management policies in Dehong Dai and Jingpo Autonomous Prefecture in Yunnan Province at the border area to Burma. The comparative method is used to analysis the border management policies in past 50 decades for the border area of Yunnan Province .This research aims to define trends within border policy and its influences to national security. This paper also examines Wendy Brown's liberal theory of border management policy. We found that it is not suitable for Sino-Burma border area. The conclusion is that the changes or instability of international economic and political situation has more influence to this cross-border ethnic area, and only innovative policy will be effective in cross-border ethnic area. So the border management policies should reflect the change of international context.

  6. Old Borders and New Bordering Capabilities: Cities as Frontier Zones

    Directory of Open Access Journals (Sweden)

    Saskia Sassen


    Full Text Available The global city is a new frontier zone. Deregulation, privatization, and new fiscal and monetary policies create the formal instruments to construct their equivalent of the old military “fort”. The city is also a strategic frontier zone for those who lack power, and allows the making of informal politics. At the same time the border is a mix of regimes, marked by protections and opportunities for corporations and high-level professionals, and implies confinement, capture and detention for migrants. The essay discusses the transformation of the city in a frontier zone and analyses the separation between the capabilities entailed by territoriality and the geographic territory tout court. The analysis focuses on the effects of neoliberal policies that, far from making this a borderless world, have actually multiplied the bordered spaces that allow firms and markets to move across conventional borders. Cities are therefore one of the key sites where new neoliberal norms are made and where new identities emerge.

  7. Droplet: A Virtual Brush Model to Simulate Chinese Calligraphy and Painting

    Institute of Scientific and Technical Information of China (English)

    Xiao-FengMi; MinTang; Jin-XiangDong


    This paper proposes a virtual brush model based on droplet operation to simulate Chinese calligraph yand traditional Chinese painting in real time. Two ways of applying droplet model to virtual calligraphy and painting are discussed in detail. The second droplet model is more elaborated and can produce more vivid results while being slightly more time-consuming. The novel feature of the proposed droplet virtual brush model successfully enables the simulation painting system to overcome the poor expressional ability of virtual brush based on particle system and avoids the complex evaluation of physical brush with solid model. The model, derived from the actual calligraphy and painting experience, due to the simplicity of the droplet operation and its powerful expressive ability, considerably improves the performance of the simulation system and maintains painting effect comparable with real brush by supporting special Chinese brush effect such as dry brush, feng and stroke diffusion.

  8. Evaluation of multi-brush anode systems in microbial fuel cells

    KAUST Repository

    Lanas, Vanessa


    The packing density of anodes in microbial fuel cells (MFCs) was examined here using four different graphite fiber brush anode configurations. The impact of anodes on performance was studied in terms of carbon fiber length (brush diameter), the number of brushes connected in parallel, and the wire current collector gage. MFCs with different numbers of brushes (one, three or six) set perpendicular to the cathode all produced similar power densities (1200±40mW/m2) and coulombic efficiencies (60%±5%). Reducing the number of brushes by either disconnecting or removing them reduced power, demonstrating the importance of anode projected area covering the cathode, and therefore the need to match electrode projected areas to maintain high performance. Multi-brush reactors had the same COD removal as single-brush systems (90%). The use of smaller Ti wire gages did not affect power generation, which will enable the use of less metal, reducing material costs. © 2013 Elsevier Ltd.

  9. Charge-driven and reversible assembly of ultra-dense polymer brushers: Formation and antifouling properties of a zipper brush

    NARCIS (Netherlands)

    Vos, de W.M.; Meijer, G.; Keizer, de A.; Cohen Stuart, M.A.; Kleijn, J.M.


    We investigated a new type of polymer brushes: the zipper brush. By adsorbing a diblock-copolymer with one charged block and one neutral block to an oppositely charged polyelectrolyte brush, a neutral polymer brush is formed on top of an almost neutral complex layer of polyelectrolytes. This neutral

  10. Reviewing the Spanish-Portuguese border: conflict, interaction and cross-border cooperation

    Directory of Open Access Journals (Sweden)

    Francisco José Calderón Vázquez


    Full Text Available European borders, or borders between European Union member states, are historical products that embody the ebbs and flows of European borderlands. These areas are evolving from past struggles and confrontations between European kingdoms toward a future of progressive European integration. Such processes are highly complex, as they involve border deactivation. In this work, we examine the evolution of the Spanish- Portuguese border from the perspective of cross-border interaction.

  11. Internal Border Controls in the European Union

    DEFF Research Database (Denmark)

    Jørgensen, Carsten Willemoes; Sørensen, Karsten Engsig


    Recent events, involving inter alia France and Denmark, have stimulated renewed interest in the introduction of different forms of border controls at the internal borders within the European Union. These border control measures are aimed at checking either persons or goods or both. Against...... the background of these events, this article analyses the existing rules regulating controls of persons and goods, and explores how these rules may or may not stand in the way of introducing border controls at the European Union’s internal borders. These events have resulted in a call for reforms of the current...

  12. Languaging the Borders of Europe


    Olivier Kramsch; Kolar Aparna; Huda Degu


    Emerging from a discomfort with the blind spots encountered within and across theorizations of language and space in the field of human geography, in this article, we argue for “making space” for conceptualizations that speak from and through the everyday territories of migrants in Europe today. Inspired by a range of writers thinking postcolonially and multi/trans-lingually, the authors draw on their own embodied migrant experience to argue for re-envisioning Europe’s borders through multipl...

  13. Cross-border reprogenetic services. (United States)

    Couture, V; Drouin, R; Tan, S-L; Moutquin, J-M; Bouffard, C


    The purpose of this review is to synthesize the current knowledge on the international movement of patients and biopsied embryo cells for pre-implantation genetic diagnosis and its different applications. Thus far, few attempts have been made to identify the specific nature of this phenomenon called 'cross-border reprogenetic services'. There is scattered evidence, both empirical and speculative, suggesting that these services raise major issues in terms of service provision, risks for patients and the children-to-come, the legal liabilities of physicians, as well as social justice. To compile this evidence, this review uses the narrative overview protocol combined with thematic analysis. Five major themes have emerged from the literature at the conjunction of cross-border treatments and reprogenetics: 'scope', 'scale', 'motivations', 'concerns', and 'governance'. Similar themes have already been observed in the case of other medical tourism activities, but this review highlights their singularity with reprogenetic services. It emphasizes the diagnostic and autologous feature of reprogenetics, the constant risk of misdiagnosis, the restriction on certain tests for medically controversial conditions, and the uncertain accessibility of genetic counseling in cross-border settings.

  14. Border preserving skin lesion segmentation (United States)

    Kamali, Mostafa; Samei, Golnoosh


    Melanoma is a fatal cancer with a growing incident rate. However it could be cured if diagnosed in early stages. The first step in detecting melanoma is the separation of skin lesion from healthy skin. There are particular features associated with a malignant lesion whose successful detection relies upon accurately extracted borders. We propose a two step approach. First, we apply K-means clustering method (to 3D RGB space) that extracts relatively accurate borders. In the second step we perform an extra refining step for detecting the fading area around some lesions as accurately as possible. Our method has a number of novelties. Firstly as the clustering method is directly applied to the 3D color space, we do not overlook the dependencies between different color channels. In addition, it is capable of extracting fine lesion borders up to pixel level in spite of the difficulties associated with fading areas around the lesion. Performing clustering in different color spaces reveals that 3D RGB color space is preferred. The application of the proposed algorithm to an extensive data-base of skin lesions shows that its performance is superior to that of existing methods both in terms of accuracy and computational complexity.

  15. Assessment of Pain Response in Capsaicin-Induced Dynamic Mechanical Allodynia Using a Novel and Fully Automated Brushing Device

    Directory of Open Access Journals (Sweden)

    Kristian G du Jardin


    Full Text Available BACKGROUND: Dynamic mechanical allodynia is traditionally induced by manual brushing of the skin. Brushing force and speed have been shown to influence the intensity of brush-evoked pain. There are still limited data available with respect to the optimal stroke number, length, force, angle and speed. Therefore, an automated brushing device (ABD was developed, for which brushing angle and speed could be controlled to enable quantitative assessment of dynamic mechanical allodynia.

  16. Gelation threshold of cross-linked polymer brushes. (United States)

    Hoffmann, Max; Lang, Michael; Sommer, Jens-Uwe


    The cross-linking of polymer brushes is studied using the bond-fluctuation model. By mapping the cross-linking process into a two-dimensional (2D) percolation problem within the lattice of grafting points, we investigate the gelation transition in detail. We show that the particular properties of cross-linked polymer brushes can be reduced to the distribution of bonds which are formed between the grafted chains, and we propose scaling arguments to relate the gelation threshold to the chain length and the grafting density. The gelation threshold is lower than the percolation threshold for 2D bond percolation because of the longer range and broad distribution of bonds formed by the cross-linking process. We term this type of percolation problem star percolation. We observe a broad crossover from mean-field to critical percolation behavior by analyzing the cluster size distribution near the gelation threshold.

  17. Photoelectricalchemical characteristics of brush plated tin sulfide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, B.; Jayachandran, M. [Central Electrochemical Research Inst., Karaikudi (India); Sanjeeviraja, C. [Alagappa Univ., Karaikudi (India). Dept. of Physics


    Thin films of tin sulfide find wide applications in optoelectronic devices and window materials for heterojunction solar cells. Thin films of p-SnS were brush plated onto tin oxide coated glass substrates from aqueous solution containing SnCl{sub 2} and Na{sub 2}S{sub 2}O{sub 3}. Deposits have been characterized with XRD and SEM for structural analysis. Hot probe method showed invariably p-type nature for all the brush plated SnS films. The variation of space charge capacitance, C{sub sc} with applied potential, V, was recorded for the PEC cell with p-SnS/Fe{sup 3+}, Fe{sup 2+}/Pt system. The spectral response of the PEC cell formed with SnS photoelectrode was studied and reported. (author)

  18. Photoelectrochemical characteristics of brush plated tin sulfide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, B.; Jayachandran, M. [Central Electrochemical Research Institute, Karaikudi 630 006 (India); Sanjeeviraja, C. [Department of Physics, Alagappa University, Karaikudi 630 006 (India)


    Thin films of tin sulfide find wide applications in optoelectronic devices and window materials for heterojunction solar cells. Thin films of p-SnS were brush plated onto tin oxide coated glass substrates from aqueous solution containing SnCl{sub 2} and Na{sub 2}S{sub 2}O{sub 3}. Deposits have been characterized with XRD and SEM for structural analysis. Hot probe method showed invariably p-type nature for all the brush plated SnS films. The variation of space charge capacitance, C{sub sc}, with applied potential, V, was recorded for the PEC cell with p-SnS/Fe{sup 3+}, Fe{sup 2+}/Pt system. The spectral response of the PEC cell formed with SnS photoelectrode was studied and reported.

  19. Usage of polymer brushes as substrates of bone cells

    Institute of Scientific and Technical Information of China (English)



    Implant methcal research and hssue eagmeer-ing both target the design of novel biomaterials for the improvement of human health and clinical applications. In order to develop improved surface coatings for hard tissue (bone)replacement materials and implant devices,we are developing micropartemed coatings consisting of polymer brushes. These are used as organic templates for the mineralization of calcium phosphate in oraer to improve adhesion of bone cells. First we give a shortaccount of the current state-of-the-art in this particular field of blomaterial development,while in the second part the preliminary results of cell culture experiments are presented,in which the biocompatibility of polymer brushes are tested on human mesenchvmal stem cells.

  20. Cholinergic urethral brush cells are widespread throughout placental mammals. (United States)

    Deckmann, Klaus; Krasteva-Christ, Gabriela; Rafiq, Amir; Herden, Christine; Wichmann, Judy; Knauf, Sascha; Nassenstein, Christina; Grevelding, Christoph G; Dorresteijn, Adriaan; Chubanov, Vladimir; Gudermann, Thomas; Bschleipfer, Thomas; Kummer, Wolfgang


    We previously identified a population of cholinergic epithelial cells in murine, human and rat urethrae that exhibits a structural marker of brush cells (villin) and expresses components of the canonical taste transduction signaling cascade (α-gustducin, phospholipase Cβ2 (PLCβ2), transient receptor potential cation channel melanostatin 5 (TRPM5)). These cells serve as sentinels, monitoring the chemical composition of the luminal content for potentially hazardous compounds such as bacteria, and initiate protective reflexes counteracting further ingression. In order to elucidate cross-species conservation of the urethral chemosensory pathway we investigated the occurrence and molecular make-up of urethral brush cells in placental mammals. We screened 11 additional species, at least one in each of the five mammalian taxonomic units primates, carnivora, perissodactyla, artiodactyla and rodentia, for immunohistochemical labeling of the acetylcholine synthesizing enzyme, choline acetyltransferase (ChAT), villin, and taste cascade components (α-gustducin, PLCβ2, TRPM5). Corresponding to findings in previously investigated species, urethral epithelial cells with brush cell shape were immunolabeled in all 11 mammals. In 8 species, immunoreactivities against all marker proteins and ChAT were observed, and double-labeling immunofluorescence confirmed the cholinergic nature of villin-positive and chemosensory (TRPM5-positive) cells. In cat and horse, these cells were not labeled by the ChAT antiserum used in this study, and unspecific reactions of the secondary antiserum precluded conclusions about ChAT-expression in the bovine epithelium. These data indicate that urethral brush cells are widespread throughout the mammalian kingdom and evolved not later than about 64.5millionyears ago.

  1. Role of gastric brush cytology in the diagnosis of giardiasis

    Directory of Open Access Journals (Sweden)

    Varma Deepali


    Full Text Available Background: Giardiasis, common in developing countries, has mostly nonspecific clinical symptoms, resulting in a limited role for preliminary tests. Aims: The present study aims to highlight the utility of endoscopic brush cytology (EBC in the diagnosis of giardiasis in clinically unsuspected cases. Materials and Methods: Endoscopic brush smears (EBS are routinely obtained in all patients presenting with gastric symptoms. The present study is a retrospective analysis of EBS, consisting of 12 cases whose smears had revealed trophozoites of Giardia lamblia . Biopsy correlation was available in five cases. Results: The patients ranged in age from 15 to 78 years (mean age: 34.08 years with a 1:1 sex ratio. Stool examination in all 12 cases yielded negative results for giardiasis. Upper gastrointestinal endoscopy was normal in all these cases. EBS from these cases revealed Giardia trophozoites, which were identified by their typical morphology. Conclusions: Endoscopic brush cytology can be used as a reliable screening tool in the diagnosis of gastro-duodenal giardiasis in clinically unsuspected cases, especially in developing countries where parasitic infections are common.


    Institute of Scientific and Technical Information of China (English)


    The paper is devoted to investigations on nanomechanical behaviors of biochips in label-free biodetections. The chip consists of Si-layer, Ti-layer, Au-layer and single-strand DNA (ssDNA) molecular brush biolayer immobilized by self-assembly technology of thiol group. Unlike previous viewpoints, such as force-bending, entropy-bending and curvature electricity effect, etc.,the piezoelectric effect of the biopolymer brush layer is viewed as the main factor that induces nanomechanical bending of biochips, and a classical macroscopic piezoelectric constitutive relation is used to describe the piezoelectric effect. A new laminated cantilever beam model with a piezoelectric biolayer in continuum mechanics, the linearized Poisson-Boltzmann equation in statistical mechanics and the scaling method in polyelectrolyte brush theory are combined to establish a relationship between the nanomechanical deflection of DNA chips and the factors such as nanoscopic structural features of ssDNA molecules, buffer salt concentration, macroscopic mechanical/piezoelectric parameters of DNA chips etc. Curve fitting of experimental data shows that the sign of the piezoelectric constant of the biolayer may control the deflection direction of DNA chips during the packaging process.

  3. Structural analysis of paintings based on brush strokes (United States)

    Sablatnig, Robert; Kammerer, Paul; Zolda, Ernestine


    The origin of works of art can often not be attributed to a certain artist. Likewise it is difficult to say whether paintings or drawings are originals or forgeries. In various fields of art new technical methods are used to examine the age, the state of preservation and the origin of the materials used. For the examination of paintings, radiological methods like X-ray and infra-red diagnosis, digital radiography, computer-tomography, etc. and color analyzes are employed to authenticate art. But all these methods do not relate certain characteristics in art work to a specific artist -- the artist's personal style. In order to study this personal style of a painter, experts in art history and image processing try to examine the 'structural signature' based on brush strokes within paintings, in particular in portrait miniatures. A computer-aided classification and recognition system for portrait miniatures is developed, which enables a semi- automatic classification and forgery detection based on content, color, and brush strokes. A hierarchically structured classification scheme is introduced which separates the classification into three different levels of information: color, shape of region, and structure of brush strokes.


    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  5. Mst4 and Ezrin Induce Brush Borders Downstream of the Lkb1/Strad/Mo25 Polarization Complex

    NARCIS (Netherlands)

    ten Klooster, Jean Paul; Jansen, Marnix; Yuan, Jin; Oorschot, Viola; Begthel, Harry; Di Giacomo, Valeria; Colland, Frederic; de Koning, John; Maurice, Madelon M.; Hornbeck, Peter; Clevers, Hans


    The human Lkb1 kinase, encoded by the ortholog of the invertebrate Par4 polarity gene, is mutated in Peutz-Jeghers cancer syndrome. Lkb1 activity requires complex formation with the pseudokinase Strad and the adaptor protein Mo25. The complex can induce complete polarization in a single isolated int

  6. Insulin uptake across the luminal membrane of the rat proximal tubule in vivo and in vitro. (United States)

    Kolman, Pavel; Pica, Angelo; Carvou, Nicolas; Boyde, Alan; Cockcroft, Shamshad; Loesch, Andrew; Pizzey, Arnold; Simeoni, Mariadelina; Capasso, Giovambattista; Unwin, Robert J


    We visualized insulin uptake in vivo across the apical membrane of the rat proximal tubule (PT) by confocal microscopy; we compared it with in vitro findings in a rat PT cell line (WKPT) using fluorescence microscopy and flow cytometry. Surface tubules were observed in vivo with a 633-nm single laser-illuminated real-time video-rate confocal scanning microscope in upright configuration for optical sectioning below the renal capsule. Fields were selected containing proximal and distal tubules; Cy5-labeled insulin was injected twice (the second time after approximately 140 min) into the right jugular vein, and the fluorescence signal (at 650-670 nm) was recorded. Fluorescence was detected almost immediately at the brush-border membrane (BBM) of PT cells only, moving inside cells within 30-40 min. As a measure of insulin uptake, the ratio of the fluorescence signal after the second injection to the first doubled (ratio: 2.11 +/- 0.26, mean +/- SE, n = 10), indicating a "priming," or stimulating, effect of insulin on its uptake mechanism at the BBM. This effect did not occur after pretreatment with intravenous lysine (ratio: 1.03 +/- 0.07, n = 6; P < 0.01). Cy2- or Cy3-labeled insulin uptake in a PT cell line in vitro was monitored by 488-nm excitation fluorescence microscopy using an inverted microscope. Insulin localized toward the apical membrane of these cells. Semiquantitative analysis of insulin uptake by flow cytometry also demonstrated a priming effect (upregulation) on insulin internalization in the presence of increasing amounts of insulin, as was observed in vivo; moreover, this effect was not seen with, or affected by, the similarly endocytosed ligand beta2-glycoprotein.

  7. Leucine transport in membrane vesicles from Chironomus riparius larvae displays a mélange of crown-group features. (United States)

    Parenti, P; Forcella, M; Pugliese, A; Giacchini, R; Rossaro, B; Hanozet, G M


    Leucine uptake into membrane vesicles from larvae of the midge Chironomus riparius was studied. The membrane preparation was highly enriched in typical brush border membrane enzymes and depleted of other membrane contaminants. In the absence of cations, there was a stereospecific uptake of l-leucine, which exhibited saturation kinetics. Parameters were determined both at neutral (Km 33 +/- 5 microM and Vmax 22.6 +/- 6.8 pmol/7s/mg protein) and alkaline (Km 46 +/- 5 microM and Vmax 15.5 +/- 2.5 pmol/7s/mg protein) pH values. At alkaline pH, external sodium increased the affinity for leucine (Km 17 +/- 1 microM) and the maximal uptake rate (Vmax 74.0 +/- 12.5 pmol/7s/mg protein). Stimulation of leucine uptake by external alkaline pH agreed with lumen pH measurements in vivo. Competition experiments indicated that at alkaline pH, the transport system readily accepts most L-amino acids, including branched, unbranched, and alpha-methylated amino acids, histidine and lysine, but has a low affinity for phenylalanine, beta-amino acids, and N-methylated amino acids. At neutral pH, the transport has a decreased affinity for lysine, glycine, and alpha-methylleucine. Taken together, these data are consistent with the presence in midges of two distinct leucine transport systems, which combine characters of the lepidopteran amino acid transport system and of the sodium-dependent system from lower neopterans.

  8. Externalization and Border-induced Displacement

    DEFF Research Database (Denmark)

    Lemberg-Pedersen, Martin

    This multidisciplinary Ph.D. dissertation engages with the timely and much debated topic of European border control. The first two chapters discuss several moral arguments claiming that border control facilitates solidarity and autonomy. These are assessed with reference to central debates in pol...... in-depth research of the privatization of border control through the cases of G4S, Finmeccanica and the EU’s EUROSUR system. The chapter links externalization of border control with European state-driven export markets and shows how states’ export credit agencies, the arms industry...... and the international banking sector all have overlapping interests in privatized border control. Chapter five identifies the multiple flows, technological, personnel, funds and data, maintaining Europe’s border infrastructure, As migrants are circulated between detention camps and countries, dumped in deserts...

  9. A model for international border management systems.

    Energy Technology Data Exchange (ETDEWEB)

    Duggan, Ruth Ann


    To effectively manage the security or control of its borders, a country must understand its border management activities as a system. Using its systems engineering and security foundations as a Department of Energy National Security Laboratory, Sandia National Laboratories has developed such an approach to modeling and analyzing border management systems. This paper describes the basic model and its elements developed under Laboratory Directed Research and Development project 08-684.

  10. Aymara paradiplomacy: Empowerment in the border

    Directory of Open Access Journals (Sweden)

    Gilberto Aranda Bustamante


    Full Text Available This article analyzes the border paradiplomacy used by more than 50 municipalities from Bolivia, Chile and Peru, named “Aymaras without Borders Strategic Alliance”. In spite of the differentiated historical construction of national identities, according to a literature review, it could be argued that there is an unprecedented border relation between these three countries. Furthermore, it is possible to conclude that this non-violent strategy has been successful in the last 15 years.

  11. Comparison of Three types of Tooth Brushes on Plaque and Gingival Indices: A Randomized Clinical Trial (United States)

    Moeintaghavi, Amir; Sargolzaie, Naser; Rostampour, Mehrnoosh; Sarvari, Sara; Kargozar, Sanaz; Gharaei, Shideh


    Objective: To compare clinical results of three types of manual tooth brushes on plaque removal efficacy and gingivitis. Method: This study is a single blind randomized trial with crossover design which involved 30 periodontaly healthy individuals. Professional plaque removal and oral hygiene instruction were performed for all the participants in the first step of our study followed by asking them to avoid brushing for 2 days. Thereafter plaque and gingivitis scores were measured using plaque and gingival indices (PI and GI). Then subjects were instructed to use Pulsar tooth brush for a two-week period and then, GI and PI indices were assessed again. After passing one-week period for wash out, subjects didn't brush for 2 days and indices were recorded again. The same procedure was done for CrossAction, and Butler 411 tooth brushes respectively and at the end of the study these variables were analyzed using SPSS software ver.16. Repeated measurement ANOVA test was used to compare the scores between different brushes. Result: Finding of this study reveals that using all three types of tooth brushes resulted in significant plaque and gingivitis reduction compared to baseline levels. Pulsar tooth brush was significantly more effective in diminishing PI and GI than Butler tooth brush (p=0.044 and 0.031 respectively). Conclusion: According to our findings all 3 types of tooth brushes are effective in reduction of plaque and gingivitis and this reduction is significantly greater for Pulsar tooth brush compared to Butler and CrossAction tooth brushes. PMID:28357006

  12. Tooth brushing, tongue cleaning and snacking behaviour of dental technology and therapist students

    Directory of Open Access Journals (Sweden)

    Clement C. Azodo


    Full Text Available Objective: To determine the tooth brushing, tongue cleaning and snacking behaviour of dental technology and therapist students. Methods: A descriptive cross-sectional study of students of Federal School of Dental Therapy and Technology Enugu, Nigeria. Self-administered questionnaire was used to obtain information on demography, frequency, duration and technique of tooth brushing and tongue cleaning as well as information on consumption of snacks. Results: A total of 242 students responded. Dental technology students made up 52.5% of the respondents and dental therapist in training made up 47.5%. Majority (63.2% of the respondents considered the strength of tooth brush when purchasing a tooth brush and 78.9% use tooth brushes with medium strength. Seven-tenth (71.9% of the respondents brush their teeth twice daily and 52.1% brush for 3–5 minutes. About one-third (30.2% brush their teeth in front of a mirror. Chewing stick was used by 51.7% of respondents in addition to the use of tooth brush. Tongue cleaning was done by 94.2% with only 9.5% using a tongue cleaner. Only 20.2% reported regular snacks consumption. Nine-tenth (90.4% of respondents were previously involved in educating others, apart from their colleagues, on tooth brushing. Conclusion: This survey revealed that most of the dental therapy and technology students had satisfactory tooth-brushing behaviour. The zeal to educate others about proper tooth brushing revealed in this study suggests that the students may be helpful in oral health promotion.

  13. Synthesis and characterization of polymer brushes for controlled adsorption of proteins (United States)

    Hoy, Olha

    Performance of biomedical devices to a large extent depends on the interactions between the device surface and the biological liquids/protein molecules. To achieve controllable interactions between the device and biomolecules and still retain the required mechanical strength on the whole, modification of the surface is often done. In the present study surface properties were modified through a polymer brush approach. After the modification, surfaces gain tunability toward protein adsorption. Mixed polymer brushes consisting of protein repelling and protein attractive components were used, with a "grafting to" method employed for the synthesis of polymer layers. First, poly(ethylene glycol), the protein repelling component of the mixed polymer brush, was tethered to the surface. Then, polyacrylic acid-b-polystyrene (the protein attractive component) was grafted on top of the previous layer. As one part of this study, the temperature dependence of grafting of the mixed brush components was studied. Surface morphology and surface properties of the mixed polymer brush were altered by treating the brush with different organic solvents. Changes in surface morphology and properties resulting from the solvent treatment were studied in dry conditions and in aqueous media. Hydrophobic interactions of the mixed polymer brush in different pH environments were also estimated. Synthesized mixed polymer brushes demonstrated a clear dependency between the external stimuli applied to the brush and the amount of the protein adsorbed onto the brush surface, allowing an effective control of protein adsorption. Attraction forces between the protein molecules and surface of he mixed polymer brush were measured using AFM and these supported the findings from the protein adsorption studies. 2-D molecular imprinting of the polymer brush approach was used to synthesize a surface with controlled positioning of the protein molecules on the surface. Protein adsorption onto the surface of the

  14. Phenotypic covariance at species’ borders (United States)


    Background Understanding the evolution of species limits is important in ecology, evolution, and conservation biology. Despite its likely importance in the evolution of these limits, little is known about phenotypic covariance in geographically marginal populations, and the degree to which it constrains, or facilitates, responses to selection. We investigated phenotypic covariance in morphological traits at species’ borders by comparing phenotypic covariance matrices (P), including the degree of shared structure, the distribution of strengths of pair-wise correlations between traits, the degree of morphological integration of traits, and the ranks of matricies, between central and marginal populations of three species-pairs of coral reef fishes. Results Greater structural differences in P were observed between populations close to range margins and conspecific populations toward range centres, than between pairs of conspecific populations that were both more centrally located within their ranges. Approximately 80% of all pair-wise trait correlations within populations were greater in the north, but these differences were unrelated to the position of the sampled population with respect to the geographic range of the species. Conclusions Neither the degree of morphological integration, nor ranks of P, indicated greater evolutionary constraint at range edges. Characteristics of P observed here provide no support for constraint contributing to the formation of these species’ borders, but may instead reflect structural change in P caused by selection or drift, and their potential to evolve in the future. PMID:23714580

  15. Improved surface property of PVDF membrane with amphiphilic zwitterionic copolymer as membrane additive (United States)

    Li, Jian-Hua; Li, Mi-Zi; Miao, Jing; Wang, Jia-Bin; Shao, Xi-Sheng; Zhang, Qi-Qing


    An attempt to improve hydrophilicity and anti-fouling properties of PVDF membranes, a novel amphiphilic zwitterionic copolymer poly(vinylidene fluoride)-graft-poly(sulfobetaine methacrylate) (PVDF-g-PSBMA) was firstly synthesized by atom transfer radical polymerization (ATRP) and used as amphiphilic copolymer additive in the preparation of PVDF membranes. The PVDF-g-PSBMA/PVDF blend membranes were prepared by immersion precipitation process. Fourier transform infrared attenuated reflection spectroscopy (FTIR-ATR) and X-ray photoelectronic spectroscopy (XPS) measurements confirmed that PSBMA brushes from amphiphilic additives were preferentially segregated to membrane-coagulant interface during membrane formation. The morphology of membranes was characterized by scanning electron microscopy (SEM). Water contact angle measurements showed that the surface hydrophilicity of PVDF membranes was improved significantly with the increasing of amphiphilic copolymer PVDF-g-PSBMA in cast solution. Protein static adsorption experiment and dynamic fouling resistance experiment revealed that the surface enrichment of PSBMA brush endowed PVDF blend membrane great improvement of surface anti-fouling ability.

  16. Improved surface property of PVDF membrane with amphiphilic zwitterionic copolymer as membrane additive

    Energy Technology Data Exchange (ETDEWEB)

    Li Jianhua, E-mail: [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China); Li Mizi; Miao Jing; Wang Jiabin; Shao Xisheng [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China); Zhang Qiqing, E-mail: [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China) and Institute of Biomedical Engineering, Chinese Academy of Medical Science, Peking Union Medical College, Tianjin 300192 (China)


    An attempt to improve hydrophilicity and anti-fouling properties of PVDF membranes, a novel amphiphilic zwitterionic copolymer poly(vinylidene fluoride)-graft-poly(sulfobetaine methacrylate) (PVDF-g-PSBMA) was firstly synthesized by atom transfer radical polymerization (ATRP) and used as amphiphilic copolymer additive in the preparation of PVDF membranes. The PVDF-g-PSBMA/PVDF blend membranes were prepared by immersion precipitation process. Fourier transform infrared attenuated reflection spectroscopy (FTIR-ATR) and X-ray photoelectronic spectroscopy (XPS) measurements confirmed that PSBMA brushes from amphiphilic additives were preferentially segregated to membrane-coagulant interface during membrane formation. The morphology of membranes was characterized by scanning electron microscopy (SEM). Water contact angle measurements showed that the surface hydrophilicity of PVDF membranes was improved significantly with the increasing of amphiphilic copolymer PVDF-g-PSBMA in cast solution. Protein static adsorption experiment and dynamic fouling resistance experiment revealed that the surface enrichment of PSBMA brush endowed PVDF blend membrane great improvement of surface anti-fouling ability.

  17. Analysis of carbon fiber brush loading in anodes on startup and performance of microbial fuel cells

    KAUST Repository

    Hutchinson, Adam J.


    Flat carbon anodes placed near a cathode in a microbial fuel cell (MFC) are adversely affected by oxygen crossover, but graphite fiber brush anodes placed near the cathode produce high power densities. The impact of the brush size and electrode spacing was examined by varying the distance of the brush end from the cathode and solution conductivity in multiple MFCs. The startup time was increased from 8 ± 1 days with full brushes (all buffer concentrations) to 13 days (50 mM), 14 days (25 mM) and 21 days (8 mM) when 75% of the brush anode was removed. When MFCs were all first acclimated with a full brush, up to 65% of the brush material could be removed without appreciably altering maximum power. Electrochemical impedance spectroscopy (EIS) showed that the main source of internal resistance (IR) was diffusion resistance, which together with solution resistance reached 100 Ω. The IR using EIS compared well with that obtained using the polarization data slope method, indicating no major components of IR were missed. These results show that using full brush anodes avoids adverse effects of oxygen crossover during startup, although brushes are much larger than needed to sustain high power. © 2011 Elsevier B.V.

  18. Interfacial properties of statistical copolymer brushes in contact with homopolymer melts. (United States)

    Trombly, David M; Pryamitsyn, Victor; Ganesan, Venkat


    We use polymer self-consistent field theory to quantify the interfacial properties of random copolymer brushes (AB) in contact with a homopolymer melt chemically identical to one of the blocks (A). We calculate the interfacial widths and interfacial energies between the melt and the brush as a function of the relative chain sizes, grafting densities, compositions of the random copolymer in the brush, and degree of chemical incompatibility between the A and B species. Our results indicate that the interfacial energies between the melt and the brush increase (signifying expulsion of the free chains from the brush) with increasing grafting density, chemical incompatibility between A and B components, and size of the free chains relative to the grafted chains. We also compare the interfacial energies of random copolymers of different sequence characteristics and find that, except for the case of very blocky or proteinlike chains, blockiness of the copolymer has only little effect on interfacial properties. Our results for interfacial energies are rationalized based on the concept of an "effective volume fraction" of the brush copolymers, f(eff), which quantifies the chemical composition of the brush segments in the interfacial zone between the brush and melt copolymers. Using this concept, we modify the strong-stretching theory of brush-melt interfaces to arrive at a simple model whose results qualitatively agree with our results from self-consistent field theory. We discuss the ramifications of our results for the design of neutral surfaces.

  19. The Borders of "Shopluk" and/or Shops without Borders

    Directory of Open Access Journals (Sweden)

    P. Hristov


    Full Text Available A historic and cultural region exists at the heart of the Balkans, known in geographic and ethnographic research as Shopluk. This is a region in which, over the last 150 years, state boundaries were moved several times as a result of 5 different wars. Today, the historic Shopluk is where the borders of three nations converge – Republic of Bulgaria, Republic of Serbia and the Republic of Macedonia – and, during the last decade, the region was declared one of the “Euroregions” on the Balkans. Despite the historical similarities in traditional culture and language of this population, in the 19th century it became a subject of nationalist ambitions and a propaganda “wars” between the new national states of Serbia and Bulgaria. The joining of Bulgarian-inhabited parts of Shopluk (the regions of today’s Dimitrovgrad and Bosilegrad in Serbia to the Kingdom of Serbs, Slovenes and Croats in 1919 created a long-lasting tension between the two countries, some residues of which can be felt in everyday relations even today. On the other hand, it has been a century-long tradition for men in this region to take part in seasonal labour migrations all over the Balkan Peninsula, despite political borders. In this way, preserving their cultural and lingual specifics, the groups of seasonal workers – migrants from Shopluk, became a bridge for cultural interaction and exchange with other regions in the neighbour countries. Even though today the population of Shopluk exhibits different national identities, historical similarities in culture and language can turn the Euroregion between Nish, Sofia and Skopje from one of the poorest on the Balkans to one of the most integrated and prosperous.

  20. Border Pedagogy Cafes: Grassroots Conversations that Matter (United States)

    Necochea, Juan; Cline, Zulmara


    This exploratory study uses qualitative methods to analyze the impact of conversations in the Border Pedagogy "Cafes" on more than 500 binational educators from the Tijuana/San Diego area on the U.S.-Mexico border. Four important themes emerged from the analysis that describe the impact of the cafes and offer a strong foundation on which…

  1. EUS-Guided Pancreatic Cyst Brushing: A Comparative Study in a Tertiary Referral Centre

    Directory of Open Access Journals (Sweden)

    Titus Thomas


    Full Text Available Context Fluid analysis obtained by EUS guided FNA is used to aid in diagnosis and management of cystic lesions in the pancreas. Complementing fluid aspiration with brushing of cyst wall may increase the cellular yield. Objective To compare cellular yield of pancreatic cyst FNA with and without wall brushing. Design Comparative study. Setting Tertiary referral centre. Patients Fifty-one patients with cystic pancreatic lesions referred for EUS-guided aspiration/sampling were included (median age 69 years; interquartile range: 49-77 years. Main outcome measures Comparing adequacy of cellular yield between EUS-guided aspiration alone vs. EUS-guided aspiration and cyst wall brushing. Intervention EUS-guided FNA and/or wall brushing (aspiration only: No. 27; brushing: No. 24. Results There was no significant difference in age (P=0.496 cyst size (P=0.084 or cyst location (P=0.227 between groups. Overall 29.5%; (15/51 of samples were acellular/insufficient with no significant difference between the two groups (22.2% in the aspiration only group vs. 37.5% in the brushing group; P=0.356. The remaining samples were adequate for cytological evaluation (77.8% vs. 62.5%; aspiration only vs. brushing groups. Seventeen cases were neoplastic (8 benign, 9 malignant. The diagnostic accuracy was 61.9% and 55.0% in aspiration only and brushing groups, respectively. Two out of 4 (50.0% patents were diagnosed as having cancer in the brushings group compared to 1/5 (20.0% in the FNA only group (P=0.524. Limitations Non-randomised series. Conclusions The cellular yield was similar in FNA and brushing group. Greater proportion of patients with malignant cystic pancreatic lesions diagnosed by EUS sampling was in the brushing group, but this did not reach statistical significance.

  2. Photoconductive Properties of Brush Plated Copper Indium Gallium Selenide Films


    Subiramaniyam, N. P.; P. Thirunavukkarasu; Murali, K. R.


    Copper indium gallium selenide (CIGS) films were deposited for the first time by the brush electrodeposition technique. X-ray diffraction studies indicated the formation of single phase chalcopyrite CIGS. Lattice parameters, dislocation density, and strain were calculated. Band gap of the films increased from 1.12 eV to 1.63 eV as the gallium concentration increased. Room temperature transport parameters of the films, namely, resistivity increased from 0.10 ohm cm to 12 ohm cm, mobility decre...

  3. Automatic brush-plating technology for component remanufacturing

    Institute of Scientific and Technical Information of China (English)

    WU Bin; XU Bin-shi; JING Xue-dong; LIU Cun-long; ZHANG Bin


    An automatic brush-plating system was developed for component remanufacturing. With this system, Ni/nano-alumina composite coatings from an electrolyte containing 20 g/L nano-alumina particles were prepared.Microstructure, surface morphology, microhardness and wear resistance of automatically plated coatings and manu ally plated coatings were investigated comparatively. The results show that the automatically plated coatings are relatively dense and uniform and have lower friction coefficient of 0. 089 under lubricant condition, when compared with manually plated coatings with friction coefficient of 0. 14.

  4. A polyhedral approach to computing border bases

    CERN Document Server

    Braun, Gábor


    Border bases can be considered to be the natural extension of Gr\\"obner bases that have several advantages. Unfortunately, to date the classical border basis algorithm relies on (degree-compatible) term orderings and implicitly on reduced Gr\\"obner bases. We adapt the classical border basis algorithm to allow for calculating border bases for arbitrary degree-compatible order ideals, which is \\emph{independent} from term orderings. Moreover, the algorithm also supports calculating degree-compatible order ideals with \\emph{preference} on contained elements, even though finding a preferred order ideal is NP-hard. Effectively we retain degree-compatibility only to successively extend our computation degree-by-degree. The adaptation is based on our polyhedral characterization: order ideals that support a border basis correspond one-to-one to integral points of the order ideal polytope. This establishes a crucial connection between the ideal and the combinatorial structure of the associated factor spaces.

  5. Revitalising Borders: Memory, Mobility and Materiality in a Latvian-Russian Border Region

    Directory of Open Access Journals (Sweden)

    Aija Lulle


    Full Text Available In this paper I investigate how an international border is 'revitalised' in political discourses as opposed to lived experiences. Based on narratives I have collected from border dwellers on both sides of the current border between Latvia and Rus-sia and placing them into a broader context of current border debates, I analyse how geographical and social mobility is remembered from Soviet times and reworked in current contexts. I argue that while politically the border is revitalised through aban-doning and forgetting the Soviet past and through the idea of constant threats in the future, locally it is revitalised through giving a life to the abandoned: memories of 'vigorous times' in life-courses and material things. People who dwell at the border did not move themselves: the international border moved several times in one cen-tury leaving border dwellers' memories and significant places on the 'other' side. I focus on how these borders were crossed in the past, how they are (not crossed now, and the social meanings assigned to these circumstances. In the current con-text I follow diverse paths of reasoning that describe how the uneven flow of goods and people through the Latvian-Russian border shapes the power dynamic against which the people living in the border area used to reconstruct imaginaries of 'Soviet times' versus 'Europe' and 'vigorous times' versus decline.


    Directory of Open Access Journals (Sweden)

    Ana-Maria Popescu (Stîngaciu


    Full Text Available To cooperate means to work and act together for a common advantage or purpose. The cooperation across borders, between different countries and regions sharing the same border, to reach common goals, is aimed to increase the overall competitiveness of the regional economy and to improve the quality of living standards for the these areas. European Union’s programmes are good accelerators for cross-border cooperation. The paper is focused on cross-border cooperation programmes at the external border of the EU and the expected impact of the allocated funds. The cross-border cooperation programmes are creating the conditions to exist the relationships between different social and economic stakeholders in order to contribute to economic and social development by supporting SME development, innovation, human resources development, civil society and local communities, increasing educational, social, cultural and sporting exchanges, improving local governance in different cross-border areas.

  7. Scaling features of the tribology of polymer brushes of increasing grafting density around the mushroom-to-brush transition (United States)

    Mayoral, E.; Klapp, J.; Gama Goicochea, A.


    Nonequilibrium coarse-grained, dissipative particle dynamics simulations of complex fluids, made up of polymer brushes tethered to planar surfaces immersed in a solvent yield nonmonotonic behavior of the friction coefficient as a function of the polymer grating density on the substrates, Γ , while the viscosity shows a monotonically increasing dependence on Γ . This effect is shown to be independent of the degree of polymerization, N , and the size of the system. It arises from the composition and the structure of the first particle layer adjacent to each surface that results from the confinement of the fluid. Whenever such layers are made up of as close a proportion of polymer beads to solvent particles as there are in the fluid, the friction coefficient shows a minimum, while for disparate proportions the friction coefficient grows. At the mushroom-to-brush transition (MBT) the viscosity scales with an exponent that depends on the characteristic exponent of the MBT (6/5) and the solvent quality exponent (ν =0.5 , for θsolvent), but it is independent of the polymerization degree (N ). On the other hand, the friction coefficient at the MBT scales as μ ˜N6 /5 , while the grafting density at the MBT scales as Γ ˜N-6 /5 when friction is minimal, in agreement with previous scaling theories. We argue these aspects are the result of cooperative phenomena that have important implications for the understanding of biological brushes and the design of microfluidics devices, among other applications of current academic and industrial interest.

  8. Improved antifouling properties of polymer membranes using a ‘layer-by-layer’ mediated method

    KAUST Repository

    Chen, Lin


    Polymeric reverse osmosis membranes were modified with antifouling polymer brushes through a \\'layer by layer\\' (LBL) mediated method. Based on pure physical electrostatic interaction, the attachment of LBL films did not alter separation performance of the membranes. In addition, the incorporation of an LBL film also helped to amplify the number of potential reaction sites on the membrane surfaces for attachment of antifouling polymer brushes, which were then attached to the surface. Attachment of the brushes included two different approaches, grafting to and grafting from. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and water contact angle measurements showed successful growth of the LBL films and subsequently the polymer brushes. Using this method to modify reverse osmosis membranes, preliminary performance testing showed the antifouling properties of the as-modified membranes were much better than the virgin membrane with no significant loss in water flux and salt rejection. © 2013 The Royal Society of Chemistry.

  9. A Colorimetric Interdental Probe as a Standard Method to Evaluate Interdental Efficiency of Interdental Brush. (United States)

    Bourgeois, D; Carrouel, F; Llodra, J C; Bravo, M; Viennot, S


    The aim of this study is to evaluate the concordance between the empirical choice of interdental brushes of different diameters compared to the gold standard, the IAP CURAPROX(©) calibrating colorimetric probe. It is carried out with the aim of facilitating the consensus development of best practices. All the subjects' interproximal spaces were evaluated using the reference technique (colorimetric probe), then after a time lapse of 1.2 ± 0.2 hours, using the empirical clinical technique (brushes) by the same examiner. Each examiner explored 3 subjects. The order the patients were examined with the colorimetric interdental probe (CIP) was random. 446 sites were selected in the study out of 468 potential sites. The correspondence of scores between interdental bushes vs. colorimetric probe is 43.0% [95%-CI: 38.5-47.6]. In 33.41% of the 446 sites, the brush is inferior to the probe; in 23.54% of cases, the brush is superior to the probe. Among the discrepancies there is thus a tendency for the subjects to use brushes with smaller diameter than that recommended by the colorimetric probe. This review has found very high-quality evidence that colorimetric probes plus interdental brushing is more beneficial than interdental brushing alone for increase the concordance between the empirical choice of interdental brushes of different diameters compared to the gold standard. Uncertainties remain and further research is required to provide detailed data on user satisfaction.

  10. Bioconjugation of protein-repellent zwitterionic polymer brushes grafted from silicon nitride

    NARCIS (Netherlands)

    Nguyen, A.T.; Baggerman, J.; Paulusse, J.M.J.; Zuilhof, H.; Rijn, van C.J.M.


    A new method for attaching antibodies to protein-repellent zwitterionic polymer brushes aimed at recognizing microorganisms while preventing the nonspecific adsorption of proteins is presented. The poly(sulfobetaine methacrylate) (SBMA) brushes were grafted from α-bromo isobutyryl initiator-function

  11. Bioconjugation of Protein-Repellent Zwitterionic Polymer Brushes Grafted from Silicone Nitride

    NARCIS (Netherlands)

    Nguyen, A.T.; Baggerman, J.; Paulusse, J.M.J.; Zuilhof, H.; Rijn, van C.J.M.


    A new method for attaching antibodies to protein-repellent zwitterionic polymer brushes aimed at recognizing microorganisms while preventing the nonspecific adsorption of proteins is presented. The poly(sulfobetaine methacrylate) (SBMA) brushes were grafted from a-bromo isobutyryl initiator-function

  12. Mixed brush of chemically and physically adsorbed polymers under shear: Inverse transport of the physisorbed species (United States)

    Pastorino, C.; Müller, M.


    We study mixed brushes under shear flow by molecular dynamics simulation with an explicit solvent. The primary brush is formed by chemically grafting polymers to a solid substrate, the secondary brush is comprised of shorter, physically end-adsorbed molecules that can laterally diffuse. By virtue of the immobility of the grafted end-points of the primary brush, its individual macromolecules perform a cyclic motion. If there is a well defined solvent-brush interface, this cyclic motion of the primary brush molecules will collectively result in the reversal of the flow inside of the primary brush. This backflow, linear in the shear rate, gives rise to the transport of the shorter, physically end-adsorbed molecules in the opposite direction of the solvent flow. We discuss which conditions are necessary to observe this counter-intuitive phenomenon. Comparing Poiseuille and Couette flow we demonstrate that the magnitude of the local shear rate at the brush-liquid interface dictates the cyclic motion and concomitant inversion of transport but that these universal effects are independent of the type of driving the flow.

  13. Synthesis and characterization of poly(3-sulfopropylmethacrylate) brushes for potential antibacterial applications. (United States)

    Ramstedt, Madeleine; Cheng, Nan; Azzaroni, Omar; Mossialos, Dimitris; Mathieu, Hans Jörg; Huck, Wilhelm T S


    This article describes the aqueous atom transfer radical polymerization synthesis of poly(3-sulfopropylmethacrylate) brushes onto gold and Si/SiO2 surfaces in a controlled manner. The effect of Cu(I)/Cu(II) ratio was examined, and a quartz crystal microbalance was used to study the kinetics of the brush synthesis. The synthesized brushes displayed a thickness from a few nanometers to several hundred nanometers and were characterized using atomic force microscopy, ellipsometry, Fourier transform infrared spectroscopy (FTIR), contact angle measurements, and X-ray photoelectron spectroscopy (XPS). The as-synthesized sulfonate brushes had very good ion-exchange properties for the ions tested in this study, i.e., Na+, K+, Cu2+, and Ag+. FTIR and XPS show that the metal ions are coordinating to sulfonate moieties inside the brushes. The brushes were easily loaded with silver ions, and the effect of silver ion concentration on silver loading of the brush was examined. The silver-loaded brushes were shown to be antibacterial toward both gram negative and gram positive bacteria. The silver leaching was studied through leaching experiments into water, NaNO3, and NaCl (physiological medium). The results from these leaching experiments are compared and discussed in the article.

  14. The Weak Interaction of Surfactants with Polymer Brushes and Its Impact on Lubricating Behavior

    NARCIS (Netherlands)

    Zhang, Ran; Ma, Shuanhong; Wei, Qiangbing; Ye, Qian; Yu, Bo; Gucht, Van Der Jasper; Zhou, Feng


    We study the weak interaction between polymers and oppositely charged surfactants and its effect on the lubricating behavior and wettability of polymer brush-covered surfaces. For cationic (PMETAC) and anionic (PSPMA) brushes, a gradual transition from ultralow friction to ultrahigh friction was

  15. Brush Seal Arrangement for the RS-68 Turbopump Set (United States)

    Nunez, D.; Ransom, D.; Prueger, G.


    The nature of the RS-68 turbopumps requires that the hydrogen seals separating the pump from the turbine must have extremely low levels of leakage and be contained in small packages. Conventional seal technologies are not able to reasonably satisfy such design requirements. A review of experimental measurements and analysis publications suggests that brush seals are well suited for the design requirements. Brush seals are shown to have less leakage than conventional labyrinth and damper seals and have no adverse effects on the rotordynamics of the machine. The bulk-flow analysis presented by Hendricks et al. is used as a guideline to create a spreadsheet that provides mass flow through the seal and heat generated by the rubbing contact of the bristles on the shaft. The analysis is anchored to published data for LN2 and LH2 leakage tests. Finally, the analysis is used to design seals for both applications. It is observed that the most important analysis parameter is the thickness of the bristle pack and its relationship to seal clearance, lay angle and pressure drop.

  16. DNA Polymer Brush Patterning through Photocontrollable Surface-Initiated DNA Hybridization Chain Reaction. (United States)

    Huang, Fujian; Zhou, Xiang; Yao, Dongbao; Xiao, Shiyan; Liang, Haojun


    The fabrication of DNA polymer brushes with spatial resolution onto a solid surface is a crucial step for biochip research and related applications, cell-free gene expression study, and even artificial cell fabrication. Here, for the first time, a DNA polymer brush patterning method is reported based on the photoactivation of an ortho-nitrobenzyl linker-embedded DNA hairpin structure and a subsequent surface-initiated DNA hybridization chain reaction (HCR). Inert DNA hairpins are exposed to ultraviolet light irradiation to generate DNA duplexes with two active sticky ends (toeholds) in a programmable manner. These activated DNA duplexes can initiate DNA HCR to generate multifunctional patterned DNA polymer brushes with complex geometrical shapes. Different multifunctional DNA polymer brush patterns can be fabricated on certain areas of the same solid surface using this method. Moreover, the patterned DNA brush surface can be used to capture target molecules in a desired manner.

  17. Highly uniform hole spacing micro brushes based on aligned carbon nanotube arrays (United States)

    Yang, Zhi; Zhu, Xingzhong; Huang, Xiaolu; Cheng, Yingwu; Liu, Yun; Geng, Huijuan; Wu, Yue; Su, Yanjie; Wei, Hao; Zhang, Yafei


    Highly uniform hole spacing micro brushes were fabricated based on aligned carbon nanotube (CNT) arrays synthesized by chemical vapor deposition method with the assistance of anodic aluminum oxide (AAO) template. Different micro brushes from CNT arrays were constructed on silicon, glass, and polyimide substrates, respectively. The micro brushes had highly uniform hole spacing originating from the regularly periodic pore structure of AAO template. The CNT arrays, serving as bristles, were firmly grafted on the substrates. The brushes can easily clean particles with scale of micrometer on the surface of silicon wafer and from the narrow spaces between the electrodes in a series of cleaning experiments. The results show the potential application of the CNT micro brushes as a cleaning tool in microelectronics manufacture field.

  18. Intrinsic properties and mechanisms of spontaneous firing in mouse cerebellar unipolar brush cells. (United States)

    Russo, Marco J; Mugnaini, Enrico; Martina, Marco


    Neuronal firing patterns are determined by the cell's intrinsic electrical and morphological properties and are regulated by synaptic interactions. While the properties of cerebellar neurons have generally been studied in much detail, little is known about the unipolar brush cells (UBCs), a type of glutamatergic interneuron that is enriched in the granular layer of the mammalian vestibulocerebellum and participates in the representation of head orientation in space. Here we show that UBCs can be distinguished from adjacent granule cells on the basis of differences in membrane capacitance, input resistance and response to hyperpolarizing current injection. We also show that UBCs are intrinsically firing neurons. Using action potential clamp experiments and whole-cell recordings we demonstrate that two currents contribute to this property: a persistent TTX-sensitive sodium current and a ruthenium red-sensitive, TRP-like cationic current, both of which are active during interspike intervals and have reversal potentials positive to threshold. Interestingly, although UBCs are also endowed with a large I(h) current, this current is not involved in their intrinsic firing, perhaps because it activates at voltages that are more hyperpolarized than those associated with autonomous activity.

  19. Intrinsic disorder of the bacterial cell division protein ZipA: coil-to-brush conformational transition. (United States)

    López-Montero, Iván; López-Navajas, Pilar; Mingorance, Jesús; Rivas, Germán; Vélez, Marisela; Vicente, Miguel; Monroy, Francisco


    The full-length ZipA protein from Escherichia coli, one of the essential elements of the cell division machinery, was studied in a surface model built as adsorbed monolayers. The interplay between lateral packing and molecular conformation was probed using a combined methodology based on the scaling analysis of the surface pressure isotherms and ellipsometry measurements of the monolayer thickness. The observed behavior is compatible with the one expected for an intrinsically disordered and highly flexible protein that is preferentially structured in a random coil conformation. At low grafting densities, ZipA coils organize in a mushroom-like regime, whereas a coil-to-brush transition occurs on increasing lateral packing. The structural results suggest a functional scenario in which ZipA acts as a flexible tether anchoring bacterial proto-ring elements to the membrane during the earlier stages of division.

  20. Comparison between observed children's tooth brushing habits and those reported by mothers

    Directory of Open Access Journals (Sweden)

    Pordeus Isabela A


    Full Text Available Abstract Background Information bias can occur in epidemiological studies and compromise scientific outcomes, especially when evaluating information given by a patient regarding their own health. The oral habits of children reported by their mothers are commonly used to evaluate tooth brushing practices and to estimate fluoride intake by children. The aim of the present study was to compare observed tooth-brushing habits of young children using fluoridated toothpaste with those reported by mothers. Methods A sample of 201 mothers and their children (aged 24-48 months from Montes Claros, Brazil, took part in a cross-sectional study. At day-care centres, the mothers answered a self-administered questionnaire on their child's tooth-brushing habits. The structured questionnaire had six items with two to three possible answers. An appointment was then made with each mother/child pair at day-care centres. The participants were asked to demonstrate the tooth-brushing practice as usually performed at home. A trained examiner observed and documented the procedure. Observed tooth brushing and that reported by mothers were compared for overall agreement using Cohen's Kappa coefficient and the McNemar test. Results Cohen's Kappa values comparing mothers' reports and tooth brushing observed by the examiner ranged from poor-to-good (0.00-0.75. There were statistically significant differences between observed tooth brushing habits and those reported by mothers (p Conclusions In general, there was low agreement between observed tooth brushing and mothers' reports. Moreover, the different methods of estimation resulted in differences in the frequencies of tooth brushing habits, indicative of reporting bias. Data regarding children's tooth-brushing habits as reported by mothers should be considered with caution in epidemiological surveys on fluoridated dentifrice use and the risk of dental fluorosis.

  1. Languaging the Borders of Europe

    Directory of Open Access Journals (Sweden)

    Olivier Kramsch


    Full Text Available Emerging from a discomfort with the blind spots encountered within and across theorizations of language and space in the field of human geography, in this article, we argue for “making space” for conceptualizations that speak from and through the everyday territories of migrants in Europe today. Inspired by a range of writers thinking postcolonially and multi/trans-lingually, the authors draw on their own embodied migrant experience to argue for re-envisioning Europe’s borders through multiple languaging practices. “Languaging”, in this view, takes linguistic practices in a migrant context as an inherently prosthetic activity, whereby any dominant, national host language is inevitably subject to the subterranean rumblings of all the languages a migrant brings with her on her global journeys. Conceived as being saturated with prosthetic “absence(s”, migrant languaging practices rework cultural geography’s bounded, inward-looking, and security-fixated understanding of the language/territory nexus, the better to open a vital space for re-envisioning language’s everyday territories as sites for translational solidarity and becoming.

  2. Semantic Borders and Incomplete Understanding. (United States)

    Silva-Filho, Waldomiro J; Dazzani, Maria Virgínia


    In this article, we explore a fundamental issue of Cultural Psychology, that is our "capacity to make meaning", by investigating a thesis from contemporary philosophical semantics, namely, that there is a decisive relationship between language and rationality. Many philosophers think that for a person to be described as a rational agent he must understand the semantic content and meaning of the words he uses to express his intentional mental states, e.g., his beliefs and thoughts. Our argument seeks to investigate the thesis developed by Tyler Burge, according to which our mastery or understanding of the semantic content of the terms which form our beliefs and thoughts is an "incomplete understanding". To do this, we discuss, on the one hand, the general lines of anti-individualism or semantic externalism and, on the other, criticisms of the Burgean notion of incomplete understanding - one radical and the other moderate. We defend our understanding that the content of our beliefs must be described in the light of the limits and natural contingencies of our cognitive capacities and the normative nature of our rationality. At heart, anti-individualism leads us to think about the fact that we are social creatures, living in contingent situations, with important, but limited, cognitive capacities, and that we receive the main, and most important, portion of our knowledge simply from what others tell us. Finally, we conclude that this discussion may contribute to the current debate about the notion of borders.

  3. Borders, boundaries and desirable wishes

    Directory of Open Access Journals (Sweden)

    Luca Pinciaroli


    Full Text Available “Borders, boundaries and desirable wishes” is the title of the residential workshop offered to a group of young adults (aged 18-25 of the Centro di Salute Mentale (Mental Health Center of the DSM Basaglia of ASL TO2 in Turin. The idea of the workshop, the definition of the objectives and the topics, which are clearly expressed in the title, come from the work of the team dedicated to group psychotherapies, which has been offering group psychodrama sessions to young adults of this age since 2008. In the delicate move to the adult age, these young adults are lost and stuck in static realities where it is not possible to open up to the dimension of desire nor to the transforming encounter with the Other, since they didn’t have the experience of boundaries and lack. These two elements are necessary to acquire the ability to make projects for oneself. During the workshop the following instruments were used: group, psychodrama and art therapy. The group, as a paternal function, ensured the presence of safe boundaries enabling individuals to experiment; psychodrama and art therapy enabled the bodies to experience encounters and transformations, using doing as a metaphor for the movement against the inhibition of doing and as a way to show oneself to the Other and be able to see the Other. 

  4. Borders in Europe: From history to everyday life

    Directory of Open Access Journals (Sweden)

    Narcís Bassols


    Full Text Available

    This article reflects on European borders and their everyday dynamics from a cross-border perspective. The article begins with a discussion of recent events that question current border policies in the European Union, reviews the literature on borders and border territories, and finally moves on to a discussion of the everyday effects of cross-border practices on the inhabitants of border spaces. Occasional reference is made to borders in the Americas to complete the picture of this topic. Although the issue of security is indeed relevant, we focus on the economic and social dimensions of cooperation. Three aspects are essential for border residents who attempt to use the advantages of the territories for their global nature: work, shopping, and place of residence. In conclusion, there has been a tendency toward the softening of borders and greater integration of border zones in the European Union.

  5. Elastic and hegemonic borders and discourse theory: Mexico’s southern border

    Directory of Open Access Journals (Sweden)

    Jorge Marengo Camacho


    Full Text Available Discourse theory is useful for understanding the creation of borders, whether material or imaginary. This paper addresses three situations on Mexico’s southern border between 2000 and 2015 in which elements of discourse theory may be applied. The outcomes were the following: 1 correlations may be made between the elements of the discourse moving from the northern to the southern border, but not in the opposite direction; 2 the process of securitising the discourse about migrants is continuous, and new securitising elements are regularly added; 3 an “elastic borders” phenomenon exists, where borders extend or retract, thereby creating new border regions; and 4 discourses around the southern border are constructed with more pejorative elements than the northern, despite the fact that crime rates are higher in the north.

  6. The U.S.-Mexico Border Infectious Disease Surveillance Project: Establishing Binational Border Surveillance (United States)

    Waterman, Stephen; Lucas, Carlos Alvarez; Falcon, Veronica Carrion; Morales, Pablo Kuri; Lopez, Luis Anaya; Peter, Chris; Gutiérrez, Alejandro Escobar; Gonzalez, Ernesto Ramirez; Flisser, Ana; Bryan, Ralph; Valle, Enrique Navarro; Rodriguez, Alfonso; Hernandez, Gerardo Alvarez; Rosales, Cecilia; Ortiz, Javier Arias; Landen, Michael; Vilchis, Hugo; Rawlings, Julie; Leal, Francisco Lopez; Ortega, Luis; Flagg, Elaine; Conyer, Roberto Tapia; Cetron, Martin


    In 1997, the Centers for Disease Control and Prevention, the Mexican Secretariat of Health, and border health officials began the development of the Border Infectious Disease Surveillance (BIDS) project, a surveillance system for infectious diseases along the U.S.-Mexico border. During a 3-year period, a binational team implemented an active, sentinel surveillance system for hepatitis and febrile exanthems at 13 clinical sites. The network developed surveillance protocols, trained nine surveillance coordinators, established serologic testing at four Mexican border laboratories, and created agreements for data sharing and notification of selected diseases and outbreaks. BIDS facilitated investigations of dengue fever in Texas-Tamaulipas and measles in California–Baja California. BIDS demonstrates that a binational effort with local, state, and federal participation can create a regional surveillance system that crosses an international border. Reducing administrative, infrastructure, and political barriers to cross-border public health collaboration will enhance the effectiveness of disease prevention projects such as BIDS. PMID:12533288

  7. Altered binding of the Cry1Ac toxin to larval membranes but not to the toxin-binding protein in Plodia interpunctella selected for resistance to different Bacillus thuringiensis isolates. (United States)

    Mohammed, S I; Johnson, D E; Aronson, A I


    Immunoblotting and cytochemical procedures were used to determine whether toxin binding was altered in strains of the Indianmeal moth, Plodia interpunctella, selected for resistance to various strains of Bacillus thuringiensis. Each of these B. thuringiensis subspecies produces a mixture of protoxins, primarily Cry1 types, and the greatest insect resistance is to the Cry1A protoxins. In several cases, however, there was also resistance to toxins not present in the B. thuringiensis strains used for selection. The Cry1Ab and Cry1Ac toxins bound equally well over a range of toxin concentrations and times of incubation to a single protein of ca. 80-kDa in immunoblots of larval membrane extracts from all of the colonies. This binding protein is essential for toxicity since a mutant Cry1Ac toxin known to be defective in binding and thus less toxic bound poorly to the 80-kDa protein. This binding protein differed in size from the major aminopeptidase N antigens implicated in toxin binding in other insects. Binding of fluorescently labeled Cry1Ac or Cry1Ab toxin to larval sections was found at the tips of the brush border membrane prepared from the susceptible but not from any of the resistant P. interpunctella. Accessibility of a major Cry1A-binding protein appears to be altered in resistant larvae and could account for their broad resistance to several B. thuringiensis toxins.

  8. Corruption, Insecurity and Border control in Niger

    DEFF Research Database (Denmark)

    Hahonou, Eric Komlavi

    In Niger, building more border offices has proven insufficient to tackle the spread of smuggling, drug trade and circulation of jihadists in the Sahel. Instead, everyday petty corruption makes border control ineffective and, while apparently benign, this has severe consequences in contexts...... of volatile security. In this policy brief, Eric Hahonou argues that without complementary activities, the multiplication of border offices could even expand opportunities for corruption. Instead, security policy should focus on creating a culture of effectiveness including systematic and regular staff...... meetings, reporting, law implementation and sanctions as well as new modalities to reward border guards and other state agents. Because corruption is, to a large extent, embedded in the social norms of the users of public service in Niger, sensitisation among transporters, passengers and traders is crucial....

  9. Of States and Borders on the Internet

    DEFF Research Database (Denmark)

    Shklovski, Irina; Struthers, David


    The space of the Internet is often described as easy to traverse with no regard for national borders. Yet few have considered what such easy border crossings on the Internet might mean to the ordinary people actually doing the traversing. Our qualitative study of regular Internet users in Kazakhs......The space of the Internet is often described as easy to traverse with no regard for national borders. Yet few have considered what such easy border crossings on the Internet might mean to the ordinary people actually doing the traversing. Our qualitative study of regular Internet users...... in Kazakhstan shows that the naming of a state-controlled space on the Internet, through the use of country code top-level domain names (ccTLDs), does in fact matter to the average user. People are aware of national boundary traversals as they navigate the Internet. Respondents in our study identified...

  10. Integrated care across borders: possibilities and complexities

    Directory of Open Access Journals (Sweden)

    Silvia Evers


    Full Text Available The main purpose of this practice paper is to describe and analyse the possibilities and complexities of integrated health care across borders. First, we portray an ideal scenario for this type of care with a case of patients suffering from rheumatoid arthritis and living in the Dutch-Belgian frontier area. It shows how cross border care enhances continuity of care/tailor-made care and the other way around. Secondly, based on different literature sources, we describe actual regulations on health care across borders. We show that these regulations can be a major hindrance to integrated care. This raises questions on the scope and content of policies directed at both cross border and integrated care.

  11. Networks communities within and across borders

    CERN Document Server

    Cerina, Federica; Pammolli, Fabio; Riccaboni, Massimo


    We investigate the impact of borders on the topology of spatially embedded networks. Indeed territorial subdivisions and geographical borders significantly hamper the geographical span of networks thus playing a key role in the formation of network communities. This is especially important in scientific and technological policy making and highlights the interplay of the internationalization pressure toward a global innovation system against the administrative borders imposed by the national and continental institutions. In this study we introduce an outreach index to quantify the impact of borders on the community structure and apply it to the case of the European and US patent co-inventors networks. We find that (a) the US connectivity decays as a power of distance, whereas we observe a faster exponential decay for Europe; (b) European network communities essentially correspond to nations and contiguous regions while US communities span multiple states across the whole country without any characteristic geog...

  12. Abuses at Europe’s borders

    Directory of Open Access Journals (Sweden)

    Duncan Breen


    Full Text Available Refugees and migrants have been regularly subjected to widespread rights violations by officials at some European borders. The EU needs to allow more legal avenues for people seeking protection to reach Europe safely.

  13. A puzzle concerning borders and identities: towards a typology of attitudes to the Irish border


    Todd, Jennifer


    State borders are typically held to shape categories of national identification. This paper explores this interrelationship in the light of empirical evidence drawn from research in the Irish border area. It begins by outlining a schema, drawn from the literature, which posits a movement from contestation of borders, to institutionalisation, to transgression. It then proceeds to show how this is reflected in scholarly and political interpretations of attitudes towards the Irish borde...

  14. Improving Nigerian Border Security -- A Comprehensive Approach (United States)


    threats, overlapping jurisdictions between different agencies, presence of private sector businesses, and partnerships with neighboring states produce us increase trade amongst West African states. Increased trade means that more goods and services will be produced , increased production means...Border Security, Cooperation and Integration, 69. 22. Adeola and Fayomi, Implications of Cross Border Migration, 6-7. 23. Ibid., 7. 24. Aluko Ola

  15. Ultrasensitive ELISA using enzyme-loaded nanospherical brushes as labels. (United States)

    Qu, Zhenyuan; Xu, Hong; Xu, Ping; Chen, Kaimin; Mu, Rong; Fu, Jianping; Gu, Hongchen


    Improving the detection sensitivity of enzyme-linked immunosorbent assay (ELISA) is of utmost importance for meeting the demand of early disease diagnosis. Herein we report an ultrasensitive ELISA system using horseradish peroxidase (HRP)-loaded nanospherical poly(acrylic acid) brushes (SPAABs) as labels. HRP was covalently immobilized in SPAABs with high capacity and activity via an efficient "chemical conjugation after electrostatic entrapment" (CCEE) process, thus endowing SPAABs with high amplification capability as labels. The periphery of SPAAB-HRP was further utilized to bind a layer of antibody with high density for efficient capture of analytes owing to the three-dimensional architecture of SPAABs. Using human chorionic gonadotrophin (hCG) as a model analyte, the SPAAB-amplified system drastically boosted the detection limit of ELISA to 0.012 mIU mL(-1), a 267-fold improvement as compared to conventional ELISA systems.

  16. The effectivity of toothpick tooth brushing method on plaque control

    Directory of Open Access Journals (Sweden)

    Chiquita Prahasanti


    Full Text Available Background: Periodontal diseases are associated with bacteria species which present in biofilms that colonize on dental surfaces. Several tooth brushing methods had been known and proved to be effective in maintaining oral hygiene. Among them, tooth pick technique was a relatively new method and its superiority in removing interproximal plaque was better than other methods. Purpose: The purpose of this study was to examine the effectivity of toothpick tooth brushing method to conventional method on periodontal health. Methods: This research was designed as an analytical observational study. Thirty samples selected from five hundred and twelve males Indonesian Air-force members in Malang, aged 18–40 yrs, with periodontal pockets (≤ 5 mm in upper or lower teeth, without crowding, gingival index minimal > 1 (moderate gingivitis, OHI-S score minimal ≥ 1.3 (moderate, without systemic diseases, do not undergone medical therapy/drug prescriptions, without using mouth rinse during study, and without prosthesis. There were thirty samples in this research and devided to two groups, fifteen samples easch. The groups were toothpick tooth brusing method and conventional method (control group. In this study oral hygiene index simplified (OHI-S, gingival index (GI, bleeding on probing (BOP and pocket depth were examined. Results: There were significant differences (p = .001 in OHI-S, GI, BOP, and PD before and after conducting each toothbrushing method, as well as differences between means (quarrel means, that were p = .003; p = .001; p = .001 and p = .001 consecutively. Conclusion: Toothpick brushing method was more effective in plaque control compared to conventional method.Latar belakang: Penyakit periodontal berhubungan dengan bakteri yang berkoloni dalam biofilm yang terdapat di permukaan gigi. Saat ini telah dikenal berbagai macam metode menyikat gigi tetapi masih belum ada penelitian tentang efek metode tersebut terhadap OHI-S. Penelitian in ingin

  17. Tooth brushing skills for the children aged 3-11 years

    Directory of Open Access Journals (Sweden)

    Das U


    Full Text Available Objectives: The objective of this study was to evaluate tooth brushing management and ability of children in relation to age and gender. Materials and Methods: The study population consisted of 45 children, who attended Department of Pedodontics and Preventive Dentistry at V.S Dental College and Hospital Bangalore. Children were divided into three groups according to age: Group I: 3-5 years, Group II: 6-8 years, and Group III: 9-11 years. Each child selected his/her favorite toothbrush and brushed his/her teeth under supervision of one instructor. The grip type during tooth brushing was recorded on a videotape and duration of tooth brushing also was noted. The data were analyzed in relation to the age and gender using the chi-square test. ANOVA was used to find if there is any significant difference between the mean brushing times in the different groups. Results: The results of statistical analysis showed that in all cases P> 0.05 for grip preferences and P < 0.001 between age groups 3-5 years and 9-11 years with respect to the mean brushing time. Conclusion: The required manual dexterity for tooth brushing was present in younger age groups.

  18. Tooth brushing among 11- to 15-year-olds in Denmark

    DEFF Research Database (Denmark)

    Bast, L. S.; Nordahl, H.; Christensen, L. B.


    OBJECTIVE: Regular tooth brushing in adolescence predicts stable tooth brushing habits later in life. Differences in tooth brushing habits by ethnic background and socioeconomic position have been suggested. We investigated migration status and social class in relation to infrequent tooth brushing...... brushing. RESULTS: 10,607 respondents: a response rate of 88.3%. Boys of lower social class had higher odds ratio (OR) of infrequent tooth brushing than girls: 1.98 (95% confidence interval 1.62-2.41) vs 1.80 (1.53-2.24). Immigrants and descendants had higher odds compared to adolescents of Danish origin......: immigrant boys OR 1.39 (1.05-1.89), girls OR 1.92 (1.47-2.50); descendant boys OR 2.53 (1.97-3.27), girls OR 2.56 (2.02-3.35). Analyses of the combined effect of social class and migration status showed that the social gradient in tooth brushing habits observed among ethnic Danes cannot be found among...

  19. Modeling lower critical solution temperature behavior of associating polymer brushes with classical density functional theory. (United States)

    Gong, Kai; Marshall, Bennett D; Chapman, Walter G


    We study the lower critical solution temperature (LCST) behavior of associating polymer brushes (i.e., poly(N-isopropylacrylamide)) using classical density functional theory. Without using any empirical or temperature-dependent parameters, we find the phase transition of polymer brushes from extended to collapsed structure with increasing temperature, indicating the LCST behavior of polymer brushes. The LCST behavior of associating polymer brushes is attributed to the interplay of hydrogen bonding interactions and Lennard-Jones attractions in the system. The effect of grafting density and molecular weight on the phase behavior of associating polymer brushes has been also investigated. We find no LCST behavior at low grafting density or molecular weight. Moreover, increasing grafting density decreases the LCST and swelling ratio of polymer brushes. Similarly, increasing molecular weight decreases the LCST but increases the swelling ratio. At very high grafting density, a partial collapsed structure appears near the LCST. Qualitatively consistent with experiments, our results provide insight into the molecular mechanism of LCST behavior of associating polymer brushes.

  20. Synthesis and Biomedical Applications of Poly((meth)acrylic acid) Brushes. (United States)

    Qu, Zhenyuan; Xu, Hong; Gu, Hongchen


    Poly((meth)acrylic acid) (P(M)AA) brushes possess a number of distinctive properties that are particularly attractive for biomedical applications. This minireview summarizes recent advances in the synthesis and biomedical applications of P(M)AA brushes and brushes containing P(M)AA segments. First, we review different surface-initiated polymerization (SIP) methods, with a focus on recent progress in the surface-initiated controlled/living radical polymerization (SI-CLRP) techniques used to generate P(M)AA brushes with a tailored structure. Next, we discuss biomolecule immobilization methods for P(M)AA brushes, including physical adsorption, covalent binding, and affinity interactions. Finally, typical biomedical applications of P(M)AA brushes are reviewed, and their performance is discussed based on their unique properties. We conclude that P(M)AA brushes are promising biomaterials, and more potential biomedical applications are expected to emerge with the further development of synthetic techniques and increased understanding of their interactions with biological systems.

  1. Compression induced phase transition of nematic brush: A mean-field theory study

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jiuzhou [Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Zhang, Xinghua, E-mail: [School of Science, Beijing Jiaotong University, Beijing 100044 (China); Yan, Dadong, E-mail: [Department of Physics, Beijing Normal University, Beijing 100875 (China)


    Responsive behavior of polymer brush to the external compression is one of the most important characters for its application. For the flexible polymer brush, in the case of low grafting density, which is widely studied by the Gaussian chain model based theory, the compression leads to a uniform deformation of the chain. However, in the case of high grafting density, the brush becomes anisotropic and the nematic phase will be formed. The normal compression tends to destroy the nematic order, which leads to a complex responsive behaviors. Under weak compression, chains in the nematic brush are buckled, and the bending energy and Onsager interaction give rise to the elasticity. Under deep compression, the responsive behaviors of the nematic polymer brush depend on the chain rigidity. For the compressed rigid polymer brush, the chains incline to re-orientate randomly to maximize the orientational entropy and its nematic order is destroyed. For the compressed flexible polymer brush, the chains incline to fold back to keep the nematic order. A buckling-folding transition takes place during the compressing process. For the compressed semiflexible brush, the chains are collectively tilted to a certain direction, which leads to the breaking of the rotational symmetry in the lateral plane. These responsive behaviors of nematic brush relate to the properties of highly frustrated worm-like chain, which is hard to be studied by the traditional self-consistent field theory due to the difficulty to solve the modified diffusion equation. To overcome this difficulty, a single chain in mean-field theory incorporating Monte Carlo simulation and mean-field theory for the worm-like chain model is developed in present work. This method shows high performance for entire region of chain rigidity in the confined condition.

  2. Assessment in vitro of brushing on dental surface roughness alteration by laser interferometry

    Directory of Open Access Journals (Sweden)

    Alessandra Miranda de Azevedo


    Full Text Available Noncarious cervical lesions (NCCLs are considered to be of multifactorial origin, normally associated with inadequate brushing. This study assessed the influence in vitro of simulated brushing on NCCL formation. Fifteen human premolars were submitted to brushing in the cementoenamel junction region, using hard-, medium- and soft-bristled brushes associated with a toothpaste of medium abrasiveness under a 200 g load, at a speed of 356 rpm for 100 minutes. The surface topography of the region was analyzed before and after brushing, by means of a laser interferometer, using "cut-off" values of 0.25 and considering roughness values in mm. The initial roughness (mm results for dentin (D / bristle consistency: 1 - soft, 2 - medium and 3 - hard were as follows: (D1 1.25 ± 0.45; (D2 1.12 ± 0.44; (D3 1.05 ± 0.41. For enamel (E / bristle consistency: 1 - soft, 2 - medium and 3 - hard, the initial results were: (E1 1.18 ± 0.35; (E2 1.32 ± 0.25; (E3 1.50 ± 0.38. After brushing, the following were the values for dentin: (D1 2.32 ± 1.99; (D2 3.30 ± 0.96; (D3 Over 500. For enamel, the values after brushing were: (E1 1.37 ± 0.31; (E2 2.15 ± 0.90; (E3 1.22 ± 0.47. Based on the results of the ANOVA and Tukey statistical analyses (a = .05 it was concluded that soft, medium and hard brushes are not capable of abrading enamel, whereas dentin showed changes in surface roughness by the action of medium- and hard-bristled brushes.

  3. Membrane dynamics

    DEFF Research Database (Denmark)

    Bendix, Pól Martin


    Current topics include membrane-protein interactions with regard to membrane deformation or curvature sensing by BAR domains. Also, we study the dynamics of membrane tubes of both cells and simple model membrane tubes. Finally, we study membrane phase behavior which has important implications...... for the lateral organization of membranes as wells as for physical properties like bending, permeability and elasticity...

  4. The Hippo pathway polarizes the actin cytoskeleton during collective migration of Drosophila border cells. (United States)

    Lucas, Eliana P; Khanal, Ichha; Gaspar, Pedro; Fletcher, Georgina C; Polesello, Cedric; Tapon, Nicolas; Thompson, Barry J


    Collective migration of Drosophila border cells depends on a dynamic actin cytoskeleton that is highly polarized such that it concentrates around the outer rim of the migrating cluster of cells. How the actin cytoskeleton becomes polarized in these cells to enable collective movement remains unknown. Here we show that the Hippo signaling pathway links determinants of cell polarity to polarization of the actin cytoskeleton in border cells. Upstream Hippo pathway components localize to contacts between border cells inside the cluster and signal through the Hippo and Warts kinases to polarize actin and promote border cell migration. Phosphorylation of the transcriptional coactivator Yorkie (Yki)/YAP by Warts does not mediate the function of this pathway in promoting border cell migration, but rather provides negative feedback to limit the speed of migration. Instead, Warts phosphorylates and inhibits the actin regulator Ena to activate F-actin Capping protein activity on inner membranes and thereby restricts F-actin polymerization mainly to the outer rim of the migrating cluster.

  5. Morphology of the Vitreoretinal Border Region

    DEFF Research Database (Denmark)

    Heegaard, Steffen

    Ophthalmology, vitreoretinal, morphology, ultrastructure, microscopy, membrana limitans interna retinae, inner limiting membrane......Ophthalmology, vitreoretinal, morphology, ultrastructure, microscopy, membrana limitans interna retinae, inner limiting membrane...

  6. Complex polymer brush gradients based on nanolithography and surface-initiated polymerization. (United States)

    Lin, Xiankun; He, Qiang; Li, Junbai


    Confined surface gradients consisting of polymer brushes have great potential in various applications such as microfluidic devices, sensors, and biophysical research. Among the available fabrication approaches, nanolithographies combined with self-assembled monolayers and surface-initiated polymerization have became powerful tools to engineer confined gradients or predefined complex gradients on the nanometre size. In this tutorial review, we mainly highlight the research progress of the fabrication of confined polymer brush gradients by using electron beam, laser, and probe-based nanolithographies and the physical base for these approaches. The application of these polymer brush gradients in biomedical research is also addressed.

  7. Study on Microstructures and Properties of Electro Brush-plating Composite Coatings

    Institute of Scientific and Technical Information of China (English)

    GUZhuo-ming; HUANGWan-juan


    In this paper, composite coatings were prepared using improved electro brush plating, and the possibility and feasibility of obtaining of composite coatings with various hard dispersion paticles (Cr2O3, SiC, ZrO, Al2O3 etc.) were studied.The microstructure, constitution, microhardness and wear resistance w, ere examined. The results show that.electro brush-plating composite coatings have finner microstruetures and higher microhardness and wear-resistance than ordinary electro brush-plating coatings.The research results can he used in repairing and surface strengthening of worn machine parts,and have practical uses.

  8. Study on Microstructures and Properties of Electro Brush-plating Composite Coatings

    Institute of Scientific and Technical Information of China (English)

    GU Zhuo-ming; HUANG Wan-juan


    In this paper, composite coatings were prepared using improved electro brush-plating, and the possibility and feasibility of obtaining of composite coatings with various hard dispersion paticles (Cr2O3, SiC, ZrO, Al2O3 etc.) were studied.The microstructure, constitution, microhardness and wear resistance were examined. The results show that,electro brush-plating composite coatings have firner microstructures and higher microhardness and wear-resistance than ordinary electro brush-plating coatings.The research results can be used in repairing and surface strengthening of worn machine parts,and have practical uses.

  9. A sequence of calculation of the modes of dimensional combined processing by an electrode brush (United States)

    Ryazantsev, A. Yu; Kirillov, O. N.; Smolentsev, V. P.; Totay, A. V.


    In the article the way of calculation of the modes of dimensional processing by an electrode brush is considered. The choice of a liquid working environment is presented. A calculation of tension in electrodes and forces of the technological current realized during processing is given. A choice of a clip of wire bunches in a processing zone, feeding an electrode brush to a non-rigid work piece. The recommended technological indicators of the process of the finishing combined treatment by an electrode brush are presented.

  10. The California Border Health Collaborative: A Strategy for Leading the Border to Better Health

    Directory of Open Access Journals (Sweden)

    Charles Edwards Matthews III


    Full Text Available There are hundreds of departments and organizations working on border health issues in the California/Baja California border region trying to protect and improve health without a collaborative structure that integrates jurisdictions and organizations. As a result, there is a need to effectively improve the health in the border region by coordinating these organizations to work together and benefit from each other’s best practices. The newly developed California Border Health Collaborative (CBHC can provide the leadership and collaborative culture to positively improve the health of the border region. This article aims to describe the development process of this collaborative to include key ingredients to success, the roles of mulit-level jurisdictions, and policy implications.This article describes the methods used to develop key aspects of collaborative leadership, strategic alignment and a common vision toward the building of this collective impact approach to border health. In addition, we describe the role of key local County (County of San Diego Live Well San Diego initiative, State, (California Department of Public Health- Office of Binational Border Health, Federal (US-Mexico Border Health Commission’s Leaders across Borders, Academia (e.g., University of California San Diego and San Diego State University and non-profit entities (e.g., Project Concern International, San Ysidro Health Center in forming the BHCC. Evaluating the consortium development process included a literature review of similar processes, a review of internal documents and an analysis of developmental events. To this point the CBHC has built a strong, cohesive collaborative on the U.S. side of the border. It is sharing and leveraging local expertise to address many border health issues. Even more importantly, the BHCC has reached a key stage in which it can effectively engage its Baja California, Mexico counterparts in a manner that will prove extremely powerful

  11. Daylong Effect of Tooth Brushing or Combination Tooth Brushing and Tongue Cleaning Using Antiplaque®Toothpaste on Volatile Sulphur Compound Levels

    Directory of Open Access Journals (Sweden)

    Indriasti Indah Wardhany


    Full Text Available Objective: to determine the daylong effect of Antiplaque® toothpaste active copound and the effect of tooth brushing or combination of tooth brushing and tongue cleaning on Volatile Sulphur Compounds (VSC levels. Methods: Clinical experimental double blinded microbiological and clinical examination. Subjects mainly from dental faculty student with or without a chief complain of halitosis. One hundred and twenty subjects were divided into four groups that consist of thirty samples each group. Two group are treatment subjects were divided into four groups that consist thirty samples each group. Two groups are treatment groups using Antiplaque® toothpaste and two groups are control groups using placebo toothpaste. The daylong effects of VSC levels are measured by Halimeter and organoleptic. The intraoral status were measured including periodontal status and tongue index. Result: There are a reduction of VSC levels in both treatment and control group, but the reduction only significant in group using Antiplaque® toothpaste (Wilcoxon signed rank test, p<0.05. There are a reduction of VSC levels in both treatment using Antiplaque® toothpaste, but the combination of tooth brushing and tongue cleaning reduced VSC levels significantly lower than tooth brushing treatment (Mann Whitney U test, P,0.05. Conclusion: Tooth brushing and tongue cleaning using Antiplaque® toothpaste significantly reduced VSC levels.DOI: 10.14693/jdi.v16i2.95

  12. Border regions as cross-border laboratories for regional and European integration

    DEFF Research Database (Denmark)

    Battrup, Gerd


    The article deals with barriers to regional cross border police cooperation. Leading police officers in the Schleswig-Holstein state police have experienced that the Danish police in recent years has become more reticent in regional cooperation across the border, especially in relation to coopera...

  13. Regional Joint Border Commands: A Pathway to Improving Collaboration and Effectiveness for Border Control (United States)


    Police xii SBI Secure Border Initiative SES Senior Executive Service SSP Secretaria de Seguridad Publica TSA Transportation Security...also been involvement from the Mexican law enforcement agency, Secretaria de Seguridad Publica (SSP) on the southwest border (CBP, 2009; ICE, 2009, p. 5

  14. Brushes and picks used on nails during the surgical scrub to reduce bacteria: a randomised trial. (United States)

    Tanner, J; Khan, D; Walsh, S; Chernova, J; Lamont, S; Laurent, T


    Though brushes are no longer used on the hands and forearms during the surgical scrub, they are still widely used on the nails. The aim of this study was to determine whether nail picks and nail brushes are effective in providing additional decontamination during a surgical hand scrub. A total of 164 operating department staff were randomised to undertake one of the following three surgical hand-scrub protocols: chlorhexidine only; chlorhexidine and a nail pick; or chlorhexidine and a nail brush. Bacterial hand sampling was conducted before and 1h after scrubbing using a modified version of the glove juice method. No statistically significant differences in bacterial numbers were found between any two of the three intervention groups. Nail brushes and nail picks used during surgical hand scrubs do not decrease bacterial numbers and are unnecessary.

  15. Trends in Social Inequality in Tooth Brushing among Adolescents: 1991-2014

    DEFF Research Database (Denmark)

    Holstein, Bjørn Evald; Bast, Lotus Sofie; Brixval, Carina Sjöberg;


    This study examines whether social inequality in tooth brushing frequency among adolescents changed from 1991 to 2014. The data material was seven comparable cross-sectional studies of nationally representative samples of 11- to 15-year-olds in Denmark with data about frequency of tooth brushing...... and occupation of parents. The total number of participants was 31,464, of whom 21.7% brushed their teeth less than the recommended 2 times a day. The absolute social inequality measured as prevalence difference between low and high social class increased from 7.7% in 1991 to 14.6% in 2014. The relative social...... inequality assessed by odds ratios for infrequent tooth brushing also increased from 1991 to 2014....

  16. Interferometry study of aqueous lubrication on the surface of polyelectrolyte brush. (United States)

    Kobayashi, Motoyasu; Tanaka, Hiroyoshi; Minn, Myo; Sugimura, Joichi; Takahara, Atsushi


    The water lubrication behavior of a polyelectrolyte brush was investigated by using double-spacer-layer ultra-thin-film interferometry to determine the thickness of the aqueous lubrication layer present at the interface between the brush and a spherical glass lens. A hydrophilic poly{[2-(methacryloyloxy)ethyl]trimethylammonium chloride} brush was prepared on an optical glass disk coated with layers of semireflective chromium and silica. The thickness of the hydrodynamic lubrication layer was estimated interferometrically. On increasing the sliding velocity from 10(-5) to 10(-1) m·s(-1), the gap between the rotating disk and loading sphere glass lens showed a marked increase to 130 nm at 2×10(-2) m·s(-1), and the friction coefficient simultaneously decreased to 0.01-0.02, indicating that the polyelectrolyte brush promoted the formation of a fluid lubrication layer that separates the rubbing surfaces, preventing direct contact and providing a low friction coefficient.

  17. Dermal Exposure during Filling, Loading and Brushing with Products Containing 2-(2-Butoxyethoxy)ethanol

    NARCIS (Netherlands)

    Gijsbers, J.H.J.; Tielemans, E.; Brouwer, D.H.; Hemmen, J.J. van


    Introduction: Limited quantitative information is available on dermal exposure to chemicals during various industrial activities. Therefore, within the scope of the EU-funded RISKOFDERM project, potential dermal exposure was measured during three different tasks: filling, loading and brushing. DEGBE

  18. pH-regulated ionic current rectification in conical nanopores functionalized with polyelectrolyte brushes. (United States)

    Zeng, Zhenping; Ai, Ye; Qian, Shizhi


    Mimicking biological ion channels capable of pH-regulated ionic transport, synthetic nanopores functionalized with pH-tunable polyelectrolyte (PE) brushes have been considered as versatile tools for active transport control of ions, fluids, and bioparticles on the nanoscale. The ionic current rectification (ICR) phenomenon through a conical nanopore functionalized with PE brushes whose charge highly depends upon the local solution properties (i.e., pH and background salt concentration) is studied theoretically for the first time. The results show that the rectification magnitude, as well as the preferential rectification direction, is sensitive to the pH stimulus. The bulk concentration of the background salt can also significantly influence the charge of the PE brushes and accordingly affect the ICR phenomenon. The obtained results provide an insightful understanding of the pH-regulated ICR and guidelines for designing nanopores functionalized with PE brushes for pH-tunable applications.

  19. Preparing high-density polymer brushes by mechanically assisted polymer assembly (MAPA) (United States)

    Wu, Tao; Efimenko, Kirill; Genzer, Jan


    We introduce a novel method of modifying the surface properties of materials. This technique, called MAPA (="mechanically assisted polymer assembly"), is based on: 1) chemically attaching polymerization initiators to the surface of an elastomeric network that has been previously stretched by a certain length, Δx, and 2) growing end-anchored macromolecules using surface initiated ("grafting from") atom transfer living radical polymerization. After the polymerization, the strain is removed from the substrate, which returns to its original size causing the grafted macromolecules to stretch away from the substrate and form a dense polymer brush. We demonstrate the feasibility of the MAPA method by preparing high-density polymer brushes of poly(acryl amide), PAAm. We show that, as expected, the grafting density of the PAAm brushes can be increased by increasing Δx. We demonstrate that polymer brushes with extremely high grafting densities can be successfully prepared by MAPA.

  20. Na+-dependent and Na+-independent betaine transport across the apical membrane of rat renal epithelium. (United States)

    Cano, Mercedes; Calonge, María L; Ilundáin, Anunciación A


    The low renal excretion of betaine indicates that the kidney efficiently reabsorbs the betaine filtered by the glomeruli but the mechanisms involved in such a process have been scarcely investigated. We have detected concentrative and non-concentrative betaine transport activity in brush-border membrane vesicles (BBMV) from rat renal cortex and medulla. The concentrative system is the Sodium/Imino-acid Transporter 1 (SIT1) because it is Na+- and Cl--dependent, electrogenic and is inhibited by an anti-SIT1 antibody. Its apparent affinity constant for betaine, Kt, is 1.1±0.5 mM and its maximal transport velocity, Vmax, 0.5±0.1 nmol betaine/mg protein/s. Inhibitors of the Na+/Cl-/betaine uptake are L-proline (75%) and cold betaine, L-carnitine and choline (40-60%). Neither creatine, TEA, taurine, β-alanine, GABA nor glycine significantly inhibited Na+/Cl-/betaine uptake. The non-concentrative betaine transport system is Na+- and H+-independent, electroneutral, with a Kt for betaine of 47±7 μM and a Vmax of 7.8±1 pmol betaine/mg protein/s. Its transport activity is nearly abolished by betaine, followed by L-carnitine (70-80%) and proline (40-50%), but a difference from the Na+/Cl-/betaine transport is that it is inhibited by TEA (approx. 50%) and unaffected by choline. The underlying carrier functions as an antiporter linking betaine entry into the BBMV with the efflux of either L-carnitine or betaine, an exchange unaffected by the anti-SIT1 antibody. As far as we know this is the first work reporting that betaine crosses the apical membrane of rat renal epithelium by SIT1 and by a Na+- and H+-independent transport system.

  1. Well-defined polyethylene molecular brushes by polyhomologation and ring opening metathesis polymerization

    KAUST Repository

    Zhang, Hefeng


    A novel strategy using polyhomologation and ring opening metathesis polymerization (ROMP) has been developed for the synthesis of well-defined polyethylene (PE) molecular brushes. Polyhomologation was used to afford an OH-terminated PE, which after transformation to the norbornyl PE macromonomer was subjected to ROMP. Kinetics of ROMP of the PE macromonomer was studied by in situ1H NMR monitoring. The brush structure was proved from HT-GPC, 1H NMR and DSC results.

  2. Uptake of pH-Sensitive Gold Nanoparticles in Strong Polyelectrolyte Brushes

    Directory of Open Access Journals (Sweden)

    Dikran Kesal


    Full Text Available The impact of electrostatic attraction on the uptake of gold nanoparticles (AuNPs into positively charged strong poly-[2-(Methacryloyloxy ethyl] trimethylammonium chloride (PMETAC polyelectrolyte brushes was investigated. In this work, PMETAC brushes were synthesized via surface-initiated atom transfer radical polymerization (Si-ATRP. PMETAC/AuNP composite materials were prepared by incubation of the polymer brush coated samples into 3-mercaptopropionic acid-capped AuNP (5 nm in diameter suspension. The electrostatic interactions were tuned by changing the surface charge of the AuNPs through variations in pH value, while the charge of the PMETAC brush was not affected. Atomic-force microscopy (AFM, ellipsometry, UV/Vis spectroscopy, gravimetric analysis and transmission electron microscopy (TEM were employed to study the loading and penetration into the polymer brush. The results show that the number density of attached AuNPs depends on the pH value and increases with increasing pH value. There is also strong evidence that the particle assembly is dependent on the pH value of the AuNP suspension. Incubation of PMETAC brushes in AuNP suspension at pH 4 led to the formation of a surface layer on top of the brush (2D assembly due to sterical hindrance of the clustered AuNPs, while incubation in AuNP suspension at pH 8 led to deeper particle penetration into the brush (3D assembly. The straightforward control of particle uptake and assembly by tuning the charge density of the nanoparticle surface is a valuable tool for the development of materials for colorimetric sensor applications.

  3. Flow and transport in brush-coated capillaries: A molecular dynamics simulation (United States)

    Dimitrov, D. I.; Klushin, L. I.; Milchev, A.; Binder, K.


    We apply an efficient method of forced imbibition to (nano-)capillaries, coated internally with a polymer brush, to derive the change in permeability and suction force, corresponding to different grafting densities and lengths of the polymer chains. While the fluid is modeled by simple point particles interacting with Lennard-Jones forces, the (end-grafted, fully flexible) polymers, which form the brush coating, are described by a standard bead-spring model. Our computer experiments reveal a significant increase in the suction force (by a factor of 4, as compared to the case of a capillary with bare walls) when the brush width approaches the tube radius. A similar growth in the suction force is found when the grafting density of the brush is systematically increased. Even though the permeability of the tube is found to decline with both growing brush width and grafting density, the combined effect on the overall fluid influx into the capillary turns out to be weak, i.e., the total fluid uptake under spontaneous imbibition decreases only moderately. Thus we demonstrate that one may transport the fluid in vertical brush-coated capillaries to a much larger height than in an equivalent capillary with bare walls. Eventually, we also study the spreading of tracer particles transported by the uptaking fluid in brush-coated capillaries with regard to the grafting density of the brush and the length of the polymers. The observed characteristic asymmetric concentration profiles of the tracers and their evolution with elapsed time are interpreted in terms of a drift-diffusion equation with a reflecting boundary that moves with the fluid front. The resulting theoretical density profiles of the tracer particles are found to be in good agreement with those observed in the computer experiment.

  4. Plaque-left-behind after brushing: intra-oral reservoir for antibacterial toothpaste ingredients


    Otten, Marieke P. T.; Busscher, Henk J.; Abbas, Frank; van der Mei, Henny C.; van Hoogmoed, Chris G.


    Objectives Plaque is never fully removed by brushing and may act as a reservoir for antibacterial ingredients, contributing to their substantive action. This study investigates the contribution of plaque-left-behind and saliva towards substantivity of three antibacterial toothpastes versus a control paste without antibacterial claims. Materials and methods First, volunteers brushed 2 weeks with a control or antibacterial toothpaste. Next, plaque and saliva samples were collected 6 and 12 h af...

  5. Hysteretic memory in pH-response of water contact angle on poly(acrylic acid) brushes. (United States)

    Yadav, Vivek; Harkin, Adrienne V; Robertson, Megan L; Conrad, Jacinta C


    We investigated the pH-dependent response of flat polyacid brushes of varying length and dispersity in the extended brush regime. Our model system consisted of poly(acrylic acid) brushes, which change from hydrophobic and neutral at low pH to hydrophilic and negatively charged at high pH, synthesized on silicon substrates using a grafting-from approach at constant grafting density. We observed three trends in the pH-response: first, the dry brush thickness increased as the pH was increased for brushes above a critical length, and this effect was magnified as the dispersity increased; second, the water contact angle measured at low pH was larger for brushes of greater dispersity; and third, brushes of sufficient dispersity exhibited hysteretic memory behavior in the pH-dependence of the contact angle, in which the contact angle upon increasing and decreasing pH differed. As a consequence, the pKa of the brushes measured upon increasing pH was consistently higher than that measured upon decreasing pH. The observed pH response is consistent with proposed changes in the conformation and charge distribution of the polyelectrolyte brushes that depend on the direction of pH change and the dispersity of the brushes.

  6. BTFS: The Border Trade Facilitation System

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, L.R.


    The author demonstrates the Border Trade Facilitation System (BTFS), an agent-based bilingual e-commerce system built to expedite the regulation, control, and execution of commercial trans-border shipments during the delivery phase. The system was built to serve maquila industries at the US/Mexican border. The BTFS uses foundation technology developed here at Sandia Laboratories' Advanced Information Systems Lab (AISL), including a distributed object substrate, a general-purpose agent development framework, dynamically generated agent-human interaction via the World-Wide Web, and a collaborative agent architecture. This technology is also the substrate for the Multi-Agent Simulation Management System (MASMAS) proposed for demonstration at this conference. The BTFS executes authenticated transactions among agents performing open trading over the Internet. With the BTFS in place, one could conduct secure international transactions from any site with an Internet connection and a web browser. The BTFS is currently being evaluated for commercialization.

  7. Formation and separation of root border cells. (United States)

    Driouich, Azeddine; Durand, Caroline; Vicré-Gibouin, Maïté


    Plant roots release a large number of border cells into the rhizosphere, which are believed to play a key role in root development and health. The formation and loss of these cells from the root cap region is a developmentally regulated process that is also controlled by phytohormones and environmental factors. The separation of border cells involves the complete dissociation of individual cells from each other and from root tissue. This process requires the activity of cell wall-degrading enzymes that solubilize the cell wall connections between cells. We present and discuss the solubilization process with an emphasis on pectin-degrading enzymes as well as the recently discovered root border-like cells of Arabidopsis thaliana.

  8. Lesion Border Detection in Dermoscopy Images

    CERN Document Server

    Celebi, M Emre; Schaefer, Gerald; Stoecker, William V; 10.1016/j.compmedimag.2008.11.002


    Background: Dermoscopy is one of the major imaging modalities used in the diagnosis of melanoma and other pigmented skin lesions. Due to the difficulty and subjectivity of human interpretation, computerized analysis of dermoscopy images has become an important research area. One of the most important steps in dermoscopy image analysis is the automated detection of lesion borders. Methods: In this article, we present a systematic overview of the recent border detection methods in the literature paying particular attention to computational issues and evaluation aspects. Conclusion: Common problems with the existing approaches include the acquisition, size, and diagnostic distribution of the test image set, the evaluation of the results, and the inadequate description of the employed methods. Border determination by dermatologists appears to depend upon higher-level knowledge, therefore it is likely that the incorporation of domain knowledge in automated methods will enable them to perform better, especially in ...

  9. Cross-border regional innovation systems

    DEFF Research Database (Denmark)

    Makkonen, Teemu; Rohde, Stephan


    elaborated through notions of geographical scale, proximity and related variety in a range of conceptual papers proposing CBRIS as a comprehensive framework for analysing regional cross-border integration. However, the empirical literature on CBRIS has failed to keep up with the advances in conceptualisation...... of understanding how suggested policy measures based on CBRIS reasoning have been implemented in border regions, and their effectiveness in promoting cross-border integration........ This paper discusses the reasons behind this mismatch which means that the concept still rests upon and draws policy suggestions based on a thin evidence base. Directions for further research are pointed out by underlining the need for holistic empirical validations of the concept together with the need...

  10. Protein adsorption can be reversibly switched on and off on mixed PEO/PAA brushes. (United States)

    Delcroix, M F; Laurent, S; Huet, G L; Dupont-Gillain, C C


    Adsorption of proteins on surfaces placed in biological fluids is a ubiquitous and mostly irreversible phenomenon, desirable or not, but often uncontrolled. Adsorption of most proteins on poly(ethylene oxide) (PEO) brushes is very limited, while the amount of proteins adsorbed on poly(acrylic acid) (PAA) brushes varies with the pH and ionic strength (I) of the protein solution. Mixed brushes of PEO and PAA are designed here to reversibly adsorb and desorb albumin, lysozyme, collagen and immunoglobulin G, four very different proteins in terms of size, solubility and isoelectric point. Protein adsorption and desorption are monitored using X-ray photoelectron spectroscopy, as well as with quartz crystal microbalance for in situ and real-time measurements. Large amounts of protein are adsorbed and then nearly completely desorbed on mixed PEO/PAA brushes by a simple pH and I trigger. The mixed brushes thus nicely combine the properties of pure PAA and pure PEO brushes. These adsorption/desorption cycles are shown to be repeated with high efficiency. The high-performance smart substrates created here could find applications in domains as diverse as biosensors, drug delivery and nanotransport.

  11. Effects of brushing in a classifying machine on the cuticles of Fuji and Gala apples

    Directory of Open Access Journals (Sweden)

    Renar João Bender


    Full Text Available The cuticle, a layer that covers the fruit epidermis, has a protective function against environmental stresses such as wind, temperature, chemicals and drought, not only when the fruit is attached to the plant, but also after harvest. Some postharvest procedures may influence the external layers of the fruit, like the cuticle. The objective of this work was to evaluate the effects of brushing in a classifying machine on the cuticles of apples under scanning electron microscopy (SEM. Two experiments were conducted to test brushing on the cultivars Fuji and Gala using heavy and smooth brushes. The experiments consisted of three replicates of three apples each, with three samples taken from the equatorial area of the fruit to be analyzed under SEM. The brushes of the classifying machine altered the cuticular layer, dragging it, modifying the structure and removing crystalloids of the cuticular wax layer, and forming cracks. There were no differences between the effects of the two types of brushes tested on the cuticles of the apples. The classifying machine used commercially is capable of producing similar effects to those encountered in the brushing experiments conducted on the prototype in the laboratory, removing partially the protective wax content of the apple’s cuticle.

  12. Endoscopic transpapillary brush cytology and forceps biopsy in patients with hilar cholangiocarcinoma

    Institute of Scientific and Technical Information of China (English)

    Andreas Weber; Claus van Weyhern; Falko Fend; Jochen Schneider; Bruno Neu; Alexander Meining; Hans Weidenbach; Roland M Schmid; Christian Prinz


    AIM:To evaluate the sensitivity of brush cytology and forceps biopsy in a homogeneous patient group with hilar cholangiocarcinoma.METHODS:Brush cytology and forceps biopsy were routinely performed in patients with suspected malignant biliary strictures.Fifty-eight consecutive patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) including forceps biopsy and brush cytology in patients with hilar cholangiocarcinoma between 1995-2005.RESULTS:Positive results for malignancy were obtained in 24/58 patients (41.4%) by brush cytology and in 31/58 patients (53.4%) by forceps biopsy.The combination of both techniques brush cytology and forceps biopsy resulted only in a minor increase in diagnostic sensitivity to 60.3% (35/58 patients).In 20/58 patients (34.5%),diagnosis were obtained by both positive cytology and positive histology,in 11/58 (19%) by positive histology (negative cytology) and only 4/58 patients (6.9%) were confirmed by positive cytology (negative histology).CONCLUSION:Brush cytology and forceps biopsy have only limited sensitivity for the diagnosis of malignant hilar tumors.In our eyes,additional diagnostic techniques should be evaluated and should become routine in patients with negative cytological and histological findings.

  13. Preparation of plasmonic vesicles from amphiphilic gold nanocrystals grafted with polymer brushes (United States)

    Song, Jibin; Huang, Peng; Chen, Xiaoyuan


    Gold nanovesicles contain multiple nanocrystals within a polymeric coating. The strong plasmonic coupling between adjacent nanoparticles in their vesicular shell makes ultrasensitive biosensing and bioimaging possible. In our laboratory, multifunctional plasmonic vesicles are assembled from amphiphilic gold nanocrystals (such as gold nanoparticles and gold nanorods) coated with mixed hydrophilic and hydrophobic polymer brushes or amphiphilic diblock co-polymer brushes. To fulfill the different requirements of biomedical applications, different polymers that are either pH=responsive, photoactive or biodegradable can be used to form the hydrophobic brush, while the hydrophilicity is maintained by polyethylene glycol (PEG). This protocol covers the preparation, surface functionalization and self-assembly of amphiphilic gold nanocrystals grafted covalently with polymer brushes. The protocol can be completed within 2 d. The preparation of amphiphilic gold nanocrystals, coated with amphiphilic diblock polymer brushes using a ‘grafting to’ method or mixed hydrophilic and hydrophobic polymer brushes using tandem ‘grafting to’ and ‘grafting from’ methods, is described. We also provide detailed procedures for the preparation and characterization of pH-responsive plasmonic gold nanovesicles from amphiphilic gold nanocrystals using a film-rehydration method that can be completed within ~3 d. PMID:27763624

  14. Functionalization of nylon membranes via surface-initiated atom-transfer radical polymerization. (United States)

    Xu, F J; Zhao, J P; Kang, E T; Neoh, K G; Li, J


    The ability to manipulate and control the surface properties of nylons is of crucial importance to their widespread applications. In this work, surface-initiated atom-transfer radical polymerization (ATRP) is employed to tailor the functionality of the nylon membrane and pore surfaces in a well-controlled manner. A simple two-step method, involving the activation of surface amide groups with formaldehyde and the reaction of the resulting N-methylol polyamide with 2-bromoisobutyryl bromide, was first developed for the covalent immobilization of ATRP initiators on the nylon membrane and its pore surfaces. Functional polymer brushes of 2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol)monomethacrylate (PEGMA) were prepared via surface-initiated ATRP from the nylon membranes. A kinetics study revealed that the chain growth from the membranes was consistent with a "controlled" process. The dormant chain ends of the grafted HEMA polymer (P(HEMA)) and PEGMA polymer (P(PEGMA)) on the nylon membranes could be reactivated for the consecutive surface-initiated ATRP to produce the corresponding nylon membranes functionalized by P(HEMA)-b-P(PEGMA) and P(PEGMA)-b-P(HEMA) diblock copolymer brushes. In addition, membranes with grafted P(HEMA) and P(PEGMA) brushes exhibited good resistance to protein adsorption and fouling under continuous-flow conditions.

  15. Meteors Without Borders: a global campaign (United States)

    Heenatigala, T.


    "Meteors Without Borders" is a global project, organized by Astronomers Without Borders and launched during the Global Astronomy Month in 2010 for the Lyrid meteor shower. The project focused on encouraging amateur astronomy groups to hold public outreach events for major meteor showers, conduct meteor-related classroom activities, photography, poetry and art work. It also uses social-media platforms to connect groups around the world to share their observations and photography, live during the events. At the International Meteor Conference 2011, the progress of the project was presented along with an extended invitation for collaborations for further improvements of the project.

  16. A CART extention using Quadratic Decision Borders

    DEFF Research Database (Denmark)

    Hartelius, Karsten


    In this article we put forward an extention to the hierarchical CART classification method which uses quadratic decision borders. The original CART applies univariate splits on individual variables as well as splits on combinations of variables to recursively partition the feature......-space into subsets which are successively more class-homogeneous. Guided by the fact that class-distributions in feature-space are very often hyper-elliptical shaped, we give an extension to the original CART which also uses quadratic shaped decision borders which can be modelled by a mean-vector and a dispersion...

  17. A CART extension using Quadratic Decision Borders

    DEFF Research Database (Denmark)

    Hartelius, Karsten


    In this article we put forward an extention to the hierarchical CART classification method which uses quadratic decision borders. The original CART applies univariate splits on individual variables as well as splits on combinations of variables to recursively partition the feature......-space into subsets which are successively more class-homogeneous. Guided by the fact that class-distributions in feature-space are very often hyper-elliptical shaped, we give an extension to the original CART which also uses quadratic shaped decision borders which can be modelled by a mean-vector and a dispersion...

  18. of the U. S.-Mexico Border

    Directory of Open Access Journals (Sweden)

    Sophie Meritet


    Full Text Available This paper studies the possible impacts of liquefied natural gas (LNG projects on natural gas prices on both sides of the U. S.-Mexico border in California. In that state gas prices are high and demand is expected to grow. Several projects for LNG facilities have been proposed and have to cope with public opinions against them. In Baja California, four LNG projects are under development given the rising demand forecasted for the next years. After a detailed study of the opportunity for LNG projects, we conclude with an analysis of the fundamentals of the current and future price formation in both sides of the U. S.- Mexico border.

  19. Polyphosphazene Based Star-Branched and Dendritic Molecular Brushes (United States)

    Henke, Helena; Posch, Sandra; Brüggemann, Oliver; Teasdale, Ian


    A new synthetic procedure is described for the preparation of poly(organo)phosphazenes with star-branched and star dendritic molecular brush type structures, thus describing the first time it has been possible to prepare controlled, highly branched architectures for this type of polymer. Furthermore, as a result of the extremely high-arm density generated by the phosphazene repeat unit, the second-generation structures represent quite unique architectures for any type of polymer. Using two relativity straight forward iterative syntheses it is possible to prepare globular highly branched polymers with up to 30 000 functional end groups, while keeping relatively narrow polydispersities (1.2–1.6). Phosphine mediated polymerization of chlorophosphoranimine is first used to prepare three-arm star polymers. Subsequent substitution with diphenylphosphine moieties gives poly(organo)phosphazenes to function as multifunctional macroinitiators for the growth of a second generation of polyphosphazene arms. Macrosubstitution with Jeffamine oligomers gives a series of large, water soluble branched macromolecules with high-arm density and hydrodynamic diameters between 10 and 70 nm. PMID:27027404

  20. Crossing the Borders: An Eco-cinecritical Analysis of Plant Wars and Bird Without Borders

    Directory of Open Access Journals (Sweden)

    Hsiao-Ching Li


    Full Text Available This essay reads two Asian nature-oriented films from the perspective of ecocinecriticism,an ecologically minded film criticism. Plant Wars, produced by PTSTaiwan, questions the demarcation between native plants and exotic plants as well asbetween plants and human beings so as to remap the in-between border area. Thestorytelling method it applies is to feature 14 currently native plants as the maincharacters, and illustrates their relationship to aboriginal people, farmers, beekeepersand to other insect species. Bird Without Borders, also produced by PTS, tells the storyof the migration journey of a group of black-faced spoonbills flying 16,000 kilometersall the way from Tainan, Taiwan, to Japan, along the border of South and North Korea,to a remote island of China to look for feeding places and then back to Taiwan to spendthe winter. Different layers of border-crossing are shown in Bird. One similarity ofthese two PTS productions is the search for border-crossing so as to redefine or revisewhat the border means. Plant questions the biological categorization of the native plantsand the exotic plants; Bird illustrates how the crew physically follows the route of thebirds’ flight which crosses the national borders to provide a vision of remapping thenatural territory through challenging the idea of a fixed “place.” Both are seeking forways to trespass the man-made borders: Plant via environmental imagination; Bird viasome physical movement. While the title of Plant Wars seemingly expresses its positionmore strongly through “wars,” Bird Without Borders explicitly asserts a dream of noborders.

  1. Alcohol-related social problems among Mexican Americans living in U.S.-Mexico border and non-border areas. (United States)

    Vaeth, Patrice A C; Caetano, Raul; Mills, Britain A; Rodriguez, Lori A


    This paper examines alcohol-related social problems among Mexican Americans living along the U.S.-Mexico border and in non-border areas. Interviews were conducted among Mexican Americans in the border regions of California, Arizona, New Mexico, and Texas (N=1307). Non-border respondents were interviewed primarily in Houston and Los Angeles (N=1288) as part of the Hispanic Americans Baseline Alcohol Survey (HABLAS). Both the border and HABLAS surveys employed multistage cluster sample designs (response rates were 67% and 76%, respectively). In the bivariate analysis, there were no significant differences between border and non-border areas in the proportion of those with one or more social problem. In non-border areas, the prevalence of alcohol problems did not differ significantly by age. However, along the border the prevalence of alcohol problems was significantly different across age groups, with 18 to 29year old men and women having the highest prevalence. The final models showed no residence effect on problem likelihood. Drinking was strongly associated with problems. Although young border residents had higher problem prevalence rates than older residents, the logistic regression models showed no effect of border residence on the likelihood of problems, indicating that problems are due to alcohol consumption, not the border environment. The border, however, did appear to influence more drinking among young people. Regardless of residence, alcohol treatment and preventive interventions tailored to Mexican Americans are essential and special attention should be focused on younger individuals near the border.

  2. Efficient drug delivery mechanisms of liposomes with tethered biopolymer brushes in aqueous solution using dissipative particle dynamics simulations

    CERN Document Server

    Goicochea, A Gama; Klapp, J; Pastorino, C


    We undertake the investigation of model liposomes covered with polyethylene glycol brushes as a case study for the mechanisms of efficient drug delivery in biologically relevant situations.Extensive non- equilibrium, coarse grained dissipative particle dynamics simulations of polymer brushes of various lengths and shear rates are performed, having in mind polymer brushes covering the surfaces of drug carrying liposomes in the human circulatory system.In particular, we calculate the viscosity and the friction coefficient for polymer brushes as functions of the shear rate and polymerization degree under theta solvent conditions, and find that the liposome brushes experience considerable shear thinning at large shear rates. The viscosity is shown to obey a scaling law at high shear rate irrespective of the brushes degree of polymerization. A new general scaling relation is obtained for the viscosity at high shear rates. These results reproduce very well trends in recent drug delivering experiments.

  3. Drilling Deeper into tooth brushing skills: Is proactive interference an under-recognized factor in oral hygiene behavior change? (United States)

    Thavarajah, Rooban; Kumar, Madan; Mohandoss, Anusa Arunachalam; Vernon, Lance T


    Proper tooth brushing is a seemingly simple motor activity that can promote oral health. Applying health theories, such as the Information-Motivation-Behavioral Skills (IMB) model, Motivational Interviewing (MI) and Integrated Health Coaching (IHC), may help optimize tooth brushing technique in those with suboptimal skills. Some motor activities, including tooth brushing, may over time become rote and unconscious actions, such that an existing habit can inhibit new learning, i.e., exert proactive interference on learning the new skill. Proactive interference may impede the acquisition of new tooth brushing skills; thus, in this report, we: (1) Review how the habit of tooth brushing is formed; (2) Postulate how proactive interference could impede the establishment of proper tooth brushing retraining; (3) Discuss the merits of this hypothesis; and (4) Provide guidance for future work in this topic within the context of an approach to behavior change that integrates IMB, MI and IHC methodology.

  4. Crossing Pedagogical Borders in the Yucatan Peninsula (United States)

    Willhauck, Susan


    A challenging intercultural teaching experience provided an opportunity for engaging embodied pedagogies that facilitated border crossings of language, age, gender, and experience. Influenced by the work of Augusto Boal, the author describes how improvisation, role-play, music, and drawing led seminary students in Mexico into sacred time and space…

  5. The border population effects of EU integration

    NARCIS (Netherlands)

    Brakman, Steven; Garretsen, Harry; van Marrewijk, Charles; Oumer, Abdella


    Border cities or regions are in theory more affected by the EU integration process than more central locations as it more drastically influences their transaction costs and market potential. We find a positive empirical effect of EU enlargement as measured by the growth in population share along the

  6. International taxation and cross-border banking

    NARCIS (Netherlands)

    Huizinga, H.P.; Voget, J.; Wagner, W.B.


    This paper examines empirically how international taxation affects the volume and pricing of cross-border banking activities for a sample of banks in 38 countries over the 1998�2008 period. International double taxation of foreign-source bank income is found to reduce banking-sector FDI. Furthermo

  7. International Taxation and Cross-Border Banking

    NARCIS (Netherlands)

    Huizinga, H.P.; Voget, J.; Wagner, W.B.


    This paper examines empirically how international taxation affects the volume and pricing of cross-border banking activities for a sample of banks in 38 countries over the 1998-2008 - period. Home country corporate income taxation of foreign-source bank income is found to reduce banking-sector FDI.

  8. Gun Trafficking and the Southwest Border (United States)


    Source of Narco Syndicates Rising Firepower,” Narcosphere, March 29, 2009. Gun Trafficking and the Southwest Border Congressional Research...50 years old, of museum interest, or derive a substantial amount of their value from the fact that they are novel , rare, bizarre, or because they

  9. Estimating Border Tax Evasion in Mozambique

    DEFF Research Database (Denmark)

    Arndt, Channing; Van Dunem, Joao Ernesto


    The relationship between border tax rates and evasion is examined for Mozambique using the methodology developed by Fisman and Wei (2004). We find that high tax rates are associated with high levels of under-reporting of import values and that tax rates have a strong and positive effect on tax ev...

  10. Implementation Issues of Cross-border Acquisitions

    DEFF Research Database (Denmark)

    Wang, Daojuan; Moini, Hamid; Kuada, John

    This study investigates the impacts of main implementation activities on the success of cross-border acquisitions (CBAs) using the survey data from a sample of 103 CBAs conducted by the companies in Scandinavia. The results of regression analysis indicate that due diligence, integration extent, a...

  11. Cross-border Mergers and Acquisitions

    DEFF Research Database (Denmark)

    Wang, Daojuan

    This paper focuses on three topics in cross-border mergers and acquisitions (CBM&As) field: motivations for CBM&As, valuation techniques and CBM&A performance (assessment and the determinants). By taking an overview of what have been found so far in academic field and investigating...

  12. Stress Resilience among Border Mexican American Women (United States)

    Guinn, Bobby; Vincent, Vern; Dugas, Donna


    The purpose of this study was to identify factors distinguishing Mexican American women living near the U.S.-Mexican border who are resilient to the experience of stress from those who are not. The study sample consisted of 418 participants ranging in age from 20 to 61 years. Data were gathered through a self-report survey instrument composed of…

  13. Borders and Borderlands in the Americas (United States)


    arbitration . This means that states do not necessarily view their borders as matters of existential import, but at most as subjects that may be... ethical , political, civil rights, privacy, and legal implications, the technology is rapidly becoming available to digitally tag, biometrically identify

  14. Cross-border flow of health information

    DEFF Research Database (Denmark)

    Di Iorio, Concetta Tania; Carinci, Fabrizio; Brillante, Massimo;


    The EUBIROD project aims to perform a cross-border flow of diabetes information across 19 European countries using the BIRO information system, which embeds privacy principles and data protection mechanisms in its architecture (privacy by design). A specific task of EUBIROD was to investigate the...

  15. Quantitative evaluation of interaction force between functional groups in protein and polymer brush surfaces. (United States)

    Sakata, Sho; Inoue, Yuuki; Ishihara, Kazuhiko


    To understand interactions between polymer surfaces and different functional groups in proteins, interaction forces were quantitatively evaluated by force-versus-distance curve measurements using atomic force microscopy with a functional-group-functionalized cantilever. Various polymer brush surfaces were systematically prepared by surface-initiated atom transfer radical polymerization as well-defined model surfaces to understand protein adsorption behavior. The polymer brush layers consisted of phosphorylcholine groups (zwitterionic/hydrophilic), trimethylammonium groups (cationic/hydrophilic), sulfonate groups (anionic/hydrophilic), hydroxyl groups (nonionic/hydrophilic), and n-butyl groups (nonionic/hydrophobic) in their side chains. The interaction forces between these polymer brush surfaces and different functional groups (carboxyl groups, amino groups, and methyl groups, which are typical functional groups existing in proteins) were quantitatively evaluated by force-versus-distance curve measurements using atomic force microscopy with a functional-group-functionalized cantilever. Furthermore, the amount of adsorbed protein on the polymer brush surfaces was quantified by surface plasmon resonance using albumin with a negative net charge and lysozyme with a positive net charge under physiological conditions. The amount of proteins adsorbed on the polymer brush surfaces corresponded to the interaction forces generated between the functional groups on the cantilever and the polymer brush surfaces. The weakest interaction force and least amount of protein adsorbed were observed in the case of the polymer brush surface with phosphorylcholine groups in the side chain. On the other hand, positive and negative surfaces generated strong forces against the oppositely charged functional groups. In addition, they showed significant adsorption with albumin and lysozyme, respectively. These results indicated that the interaction force at the functional group level might be

  16. Effect of toothbrushes and denture brushes on heat-polymerized acrylic resins. (United States)

    de Freitas Pontes, Karina Matthes; de Holanda, Janaína Câncio; Fonteles, Cristiane Sa Roriz; Pontes, Cassio de Barros; Lovato da Silva, Cláudia Helena; Paranhos, Helena de Freitas Oliveira


    It is important to choose an appropriate brush for denture cleaning to prevent damage to the surface properties of prosthetic devices. The purpose of this study was to evaluate the abrasiveness of toothbrushes and denture brushes on boiled and microwave-processed acrylic resins. Specimens of 4 resin brands were prepared (n = 30). Five brands of brushes (n = 6) were used in a toothbrushing machine, first for 17,800 strokes and then for an additional 35,600 strokes (total of 53,400), at a load of 200 g. An analytical balance and a profilometer were used to assess the weight and surface roughness, respectively, before and after 17,800 and 53,400 strokes. Analysis of variance and Tukey tests were used for data analysis (α = 0.05). Weight loss increased with time, while surface roughness remained the same. There were no statistically significant differences among toothbrushes and denture brushes in the resulting weight loss (17,800 strokes, 1.83 mg; 53,400 strokes, 3.78 mg) or surface roughness (17,800 or 53,400 strokes, 0.14 µm). The weight loss values after 53,400 brush strokes indicated that Clássico (2.28 mg) and VIPI Wave (2.75 mg) presented significantly greater abrasion resistance than Lucitone 550 (3.36 mg) and Onda-Cryl (2.85 mg) (P < 0.05). The type of brush and the polymerization method did not influence resin wear after brushing.


    Directory of Open Access Journals (Sweden)

    Ceren Damla Özbek


    Full Text Available Purpose: As they grow, children develop their attitude and behavior related to tooth brushing by taking their parents’ oral-dental health behavior as an example. The purpose of this study was to assess whether there was a similarity in tooth brushing between primary school-age children and their parents presenting to the Department of Oral, Dental and Jaw Diseases and Surgery and the Department of Pedodontics, School of Dental Medicine, Istanbul University. Patients and Methods: The study included 126 children and their parents, as totally 252 subjects. The data on oral hygiene of the subjects were obtained using a questionnaire form including questions on the qualitative-quantitative tooth brushing habits of the children and their parents and the socio-demographic characteristics of their families. Results: In most of the cases, there was a similarity between children and their parents in terms of frequency of dentist visits, the therapy they underwent in their last dentist visit, the cause of caries, the frequency of tooth brushing, the material used for oral hygiene, the duration of tooth brushing, method of tooth brushing, and tooth sites most brushed, which showed a significant association between children and their parents (p<0.01. Conclusion: Correct knowledge given to the children by their families will positively affect the oral-dental health of the children. Thus, firstly, correct knowledge should be given to the parents so that they can successfully carry out their responsibility in being the correct model for their children in oral-dental health.

  18. Light-responsive polymer surfaces via postpolymerization modification of grafted polymer-brush structures. (United States)

    Dübner, Matthias; Spencer, Nicholas D; Padeste, Celestino


    Light-induced, spatially well-defined, reversible switching of surface properties enables the creation of remote-controlled smart surfaces. We have taken advantage of the unique high-resolution structuring capabilities of extreme ultraviolet (EUV) interference lithography to produce nanostructured photoresponsive polymer brushes. Patterns of poly(glycidyl methacrylate) (PGMA) and poly(methacrylic acid) (PMAA) were grafted from two different 100 μm thick fluoropolymer substrates by means of a radiation-initiated, grafting-from approach based on free-radical polymerization (FRP). Photochromic properties were introduced via novel one- or two-step postpolymerization modifications with spiropyran (SP) derivatives, which allowed us to control the number of photochromic groups on the polymer brushes. Depending on the degree of functionalization and the local chemical environment, the SP moieties can open upon UV-light exposure to form zwitterionic, deeply colored, and fluorescent merocyanines (MCs) and reclose to the colorless SP configuration via thermal or visible light-induced relaxation. Switching kinetics were studied by means of time-resolved fluorescence microscopy and compared with kinetic measurements of the SP moiety in solution. The results indicated the importance, for the intensity of the switching, of the local chemical environment provided by both the polymer brush and added solvents, and showed the predominant influence on the ring-closing kinetics of polar solvents, which stabilize the MC form. To allow further characterization of the polymer-brush arrangements on a macroscopic scale, similar, but unstructured brush systems were grafted from fluoropolymers after large-area activation using EUV radiation or argon plasma. All steps of the postpolymerization modification were characterized in detail using attenuated total reflection infrared (ATR-IR) spectroscopy. Furthermore, a light-induced reversible static-contact-angle switch with a range of up to 15

  19. Single-chain-in-mean-field simulations of weak polyelectrolyte brushes (United States)

    Léonforte, F.; Welling, U.; Müller, M.


    Structural properties of brushes which are composed of weak acidic and basic polyelectrolytes are studied in the framework of a particle-based approach that implicitly accounts for the solvent quality. Using a semi-grandcanonical partition function in the framework of the Single-Chain-in-Mean-Field (SCMF) algorithm, the weak polyelectrolyte is conceived as a supramolecular mixture of polymers in different dissociation states, which are explicitly treated in the partition function and sampled by the SCMF procedure. One obtains a local expression for the equilibrium acid-base reaction responsible for the regulation of the charged groups that is also incorporated to the SCMF sampling. Coupled to a simultaneous treatment of the electrostatics, the approach is shown to capture the main features of weak polyelectrolyte brushes as a function of the bulk pH in the solution, the salt concentration, and the grafting density. Results are compared to experimental and theoretical works from the literature using coarse-grained representations of poly(acrylic acid) (PAA) and poly(2-vinyl pyridine) (P2VP) polymer-based brushes. As the Born self-energy of ions can be straightforwardly included in the numerical approach, we also study its effect on the local charge regulation mechanism of the brush. We find that its effect becomes significant when the brush is dense and exposed to high salt concentrations. The numerical methodology is then applied (1) to the study of the kinetics of collapse/swelling of a P2VP brush and (2) to the ability of an applied voltage to induce collapse/swelling of a PAA brush in a pH range close to the pKa value of the polymer.

  20. Measurement of Tooth Brushing Frequency, Time of Day and Duration of Adults and Children in Jakarta, Indonesia

    Directory of Open Access Journals (Sweden)

    Anton Rahardjo


    Full Text Available Epidemiological study of tooth brushing is essential to evaluate dental health of a country. Objective: To obtain data on tooth brushing frequency, time of day and duration from adults and children in Jakarta, Indonesia. Methods: Toothbrushes containing data loggers were distributed to 120 random families in Jakarta to record how many times a day, when and for how long subjects brushed their teeth. The families were each composed of a mother, father and two children aged between 6 and 15 years. Results: The mean brushing frequency of the population was 1.27 times per day. The majority of the tooth brushing (46% was performed in the morning. The mean tooth brushing duration of this population was 57.29 seconds. The mothers’ tooth brushing frequencies tended to be higher than that of the other family members, and the fathers tended to brush their teeth longer. Conclusion: Effective education aimed at increasing both the duration and frequency of tooth brushing from once to twice per day is urgently required in Indonesia.DOI: 10.14693/jdi.v21i3.251

  1. Effects of carbon brush anode size and loading on microbial fuel cell performance in batch and continuous mode

    KAUST Repository

    Lanas, Vanessa


    Larger scale microbial fuel cells (MFCs) require compact architectures to efficiently treat wastewater. We examined how anode-brush diameter, number of anodes, and electrode spacing affected the performance of the MFCs operated in fed-batch and continuous flow mode. All anodes were initially tested with the brush core set at the same distance from the cathode. In fed-batch mode, the configuration with three larger brushes (25 mm diameter) produced 80% more power (1240 mW m-2) than reactors with eight smaller brushes (8 mm) (690 mW m-2). The higher power production by the larger brushes was due to more negative and stable anode potentials than the smaller brushes. The same general result was obtained in continuous flow operation, although power densities were reduced. However, by moving the center of the smaller brushes closer to the cathode (from 16.5 to 8 mm), power substantially increased from 690 to 1030 mW m-2 in fed batch mode. In continuous flow mode, power increased from 280 to 1020 mW m-2, resulting in more power production from the smaller brushes than the larger brushes (540 mW m-2). These results show that multi-electrode MFCs can be optimized by selecting smaller anodes, placed as close as possible to the cathode. © 2013 Elsevier B.V. All rights reserved.

  2. A Monte Carlo study of fluctuating polymer-grafted membranes. (United States)

    Laradji, Mohamed


    Using Monte Carlo simulations of an off-lattice model, we study the elastic properties of polymer-grafted membranes. Our results are found to be in good agreement with those predicted by the classical path approximation of the self-consistent field theory and scaling theory based on de Gennes' blob picture. In particular, we found that when the membrane is grafted on both sides by brushes with same molecular weight N and grafting density sigma, the excess bending modulus induced by the polymers scales as N3 sigmaalpha where alpha is consistent with 7/3, as predicted by the self-consistent field theory, and 5/2, as predicted by the scaling theory. When the polymers are grafted to one side of the membrane only, the membrane bends away from the polymers with a spontaneous curvature with a scaling that is consistent with both scaling and self-consistent field theories. When the thickness of the brush exceeds the membrane's spontaneous radius of curvature, the bending modulus approaches a constant which is of the same order as the bending modulus of the bare membrane.

  3. Partnership and Cooperation Models in Cross-Border Areas

    Directory of Open Access Journals (Sweden)

    Marcela Slusarciuc


    Full Text Available The paper aims at exploring the partnership and cooperation issues in cross-border areas in European Union. The theoretical part of the papers is defining the role of the borders in the framework of the European Union enlarged and it includes a review of forms of cooperation and principles applicable in cross-border cooperation considered by the Council of Europe and the European Union or the Association of European Border Regions. Further there are identified in the specific literature important challenges and key points that are marking the cross-border partnerships. The last part of the paper is focusing on some examples of cross-border cooperation, making distinction between two main situations: the border between Member States and the borders between EU and neighbouring countries.

  4. Membrane fusion

    DEFF Research Database (Denmark)

    Bendix, Pól Martin


    At Stanford University, Boxer lab, I worked on membrane fusion of small unilamellar lipid vesicles to flat membranes tethered to glass surfaces. This geometry closely resembles biological systems in which liposomes fuse to plasma membranes. The fusion mechanism was studied using DNA zippering...... between complementary strands linked to the two apposing membranes closely mimicking the zippering mechanism of SNARE fusion complexes....

  5. Biobased Membrane

    NARCIS (Netherlands)

    Koenders, E.A.B.; Zlopasa, J.; Picken, S.J.


    The present invention is in the field of a composition for forming a bio-compatible membrane applicable to building material, such as concrete, cement, etc., to a meth od of applying said composition for forming a bio-compatible membrane, a biocompatible membrane, use of said membrane for various pu

  6. Contamination impact of station brush fire on cleanroom facilities (United States)

    Carey, Philip A.; Blakkolb, Brian K.


    Brush and forest fires, both naturally occurring and anthropogenic in origin, in proximity to space flight hardware processing facilities raise concerns about the threat of contamination resulting from airborne particulate and molecular components of smoke. Perceptions of the severity of the threat are possibly heightened by the high sensitivity of the human sense of smell to some components present in the smoke of burning vegetation. On August 26th, 2009, a brushfire broke out north of Pasadena, California, two miles from the Jet Propulsion Laboratory. The Station Fire destroyed over 160,000 acres, coming within a few hundred yards of JPL. Smoke concentrations on Lab were very heavy over several days. All Lab operations were halted, and measures were taken to protect personnel, critical hardware, and facilities. Evaluation of real-time cleanroom monitoring data, visual inspection of facilities, filter systems, and analysis of surface cleanliness samples revealed facility environments and hardware were minimally effected. Outside air quality easily exceeded Class Ten Million. Prefilters captured most large ash and soot; multi-stage filtration greatly minimized the impact on the HEPA/ULPA filters. Air quality in HEPA filtered spacecraft assembly cleanrooms remained within Class 10,000 specification throughout. Surface cleanliness was minimally affected, as large particles were effectively removed from the airstream, and sub-micron particles have extremely long settling rates. Approximate particulate fallout within facilities was 0.00011% area coverage/day compared to 0.00038% area coverage/day during normal operations. Deposition of condensable airborne components, as measured in real time, peaked at approximately 1.0 ng/cm2/day compared to 0.05 ng/cm2/day nominal.

  7. Modeling of polymer brush grafted nanoparticles for algal harvesting (United States)

    Goins, Jason

    Microalgae derived biofuel shows great potential as a replacement to petroleum based fuels. However, industrial scale and economical production of fuel from microalgae suffer from an expensive dewatering step brought on by the organism's specific cell properties. A retrievable, paramagnetic nanoparticle polyelectrolyte brush (NPPB) has been designed as a flocculation agent to provide a low cost method in collecting algal biomass in biofuel production. In conjunction with experiment, subsequent theoretical investigations have been conducted in order to understand experimental observations and inform future design. A strategy has been implemented to provide informative descriptions for the relationship between flocculation agent parameters and dewatering efficiency. We studied the effect altering the degree of polymerization and monomer charge fraction had on the harvesting efficiency by considering flocculation as the criteria for harvesting. As the number of charges on the polymer backbone of the NPPB is increased, less NPPB concentrations are required to achieve equal harvesting efficiencies. This is a result of needing less NPPB to completely screen the effective charge on the algae surface. However, the Debye length limits the amount of charge on the algae surface one NPPB can screen. Using the free energy calculations for the complete set of pair interactions between the NPPB and the algae, we determined how many adsorbed NPPB were required in order for the force between coated algae to become attractive at some algae surface separation. This corresponded to the NPPB bridging two algae surfaces. NPPB with higher monomer charge fractions and degree of polymerizations led to a stronger bridging bond and larger bridging gap that could outweigh the algae pair repulsion. Optimized structures maximize these effects.

  8. Hmong Across Borders or Borders Across Hmong? Social and Political Influences Upon Hmong People

    Directory of Open Access Journals (Sweden)

    Prasit Leepreecha


    Full Text Available The Hmong are a transnational ethnic people, because of their dispersal from China into Southeast Asia in the early 19th century and from Southeast Asia to Western countries from 1975 onward. However, even within the context of Southeast Asia and southern China, the Hmong are a transnational ethnic group, due to state boundaries and the enforcement of international laws.Scholars speak as though the Hmong population has crossed political and legal borders by their movement across state boundaries and international borders. However, I argue that it is the political, social, and legal borders that have cut across the Hmong people and subjected them to be citizens of different modern nation-states. Even in the present time, these borders still, and continuously, play important roles that cross and divide the Hmong people into distinctive subgroups and fragments. In this article, I will start by describing the generally understood situation of Hmong being across national borders, and then will explain my argument that borders are across the Hmong.

  9. International Border Management Systems (IBMS) Program : visions and strategies.

    Energy Technology Data Exchange (ETDEWEB)

    McDaniel, Michael; Mohagheghi, Amir Hossein


    Sandia National Laboratories (SNL), International Border Management Systems (IBMS) Program is working to establish a long-term border security strategy with United States Central Command (CENTCOM). Efforts are being made to synthesize border security capabilities and technologies maintained at the Laboratories, and coordinate with subject matter expertise from both the New Mexico and California offices. The vision for SNL is to provide science and technology support for international projects and engagements on border security.

  10. BorderTourism--- IntheCaseofShaTauKokTourismexploitation

    Institute of Scientific and Technical Information of China (English)

    Li Fangzhou


    The diversity is the foundation of tourism.Border regions witness the change of the history, and retain valuable heritages and unique vil ages. Because of the common border protection regulations, natural beauties and cultural landscapes can be also wel preserved, leaving abundant and precious tourism resources for younger generations.Combining with the sha tau kok border region and the surrounding site,analysis of the feasibility of border tourism and chal enges.

  11. Geoenvironmental problems and cross-border cooperation in Central America

    Institute of Scientific and Technical Information of China (English)

    Marek Graniczny; Jonas Satkunas; Jurga Lazauskiene; Jiri Sebesta


    @@ The International Workshop on "Geoenvironmental problems and cross-border cooperation in Central America" was organized in Managua, Nicaragua, 5-8 December, 2005 by the Working Group International Borders-Geoenvironmental Concerns (IBC), under the IUGS Commission on Geosciences for Environmental Management (GEM) and in the framework of the IUGS funded project "Application of geosciences for sustainable development of cross-border areas(GEOCrossBorder)".

  12. The synthesis of hydrogels with controlled distribution of polymer brushes in hydrogel network

    Energy Technology Data Exchange (ETDEWEB)

    Sun, YuWei; Zhou, Chao; Zhang, AoKai; Xu, LiQun; Yao, Fang [School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing, Jiangsu Province, 211189 (China); Cen, Lian, E-mail: [National Tissue Engineering Center of China, No.68, East Jiang Chuan Road, Shanghai, 200241 (China); School of Chemical Engineering, East China University of Science and Technology, No.130, Mei Long Road, Shanghai, 200237 (China); Fu, Guo-Dong, E-mail: [School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing, Jiangsu Province, 211189 (China)


    Highlights: • Many biological tissues are 3-dimensionally asymmetric in structure and properties, it would be desirable if hydrogels could bear such structural similarity with specialized surface and bulk properties. Moreover, gradual but continuous variation in spatial structural and property is also a common phenomenon in biological tissues, such as interfaces between bone and tendon, or between bone and cartilage. Hence, the development of a method to introduce well-defined functional polymer brushes on PEG hydrogels, especially with precisely controlled spatial structure in 3-dimensions, would impart the hydrogels with special functionalities and wider applications. Poly(ethylene glycol) (PEG) hydrogels with 3-dimensionally controlled well-defined poly(N-isopropylacrylamide) (poly(NIPAAm)) brushes were prepared by combined copper(I)-catalyzed azide-alkyne cycloaddition (“Click Chemistry”) and atom transfer radical polymerization (ATRP). The resulting hydrogels were presented as representatives with their detailed synthesis routes and characterization. H{sub PEG}-S-poly(NIPAAm) is a hydrogel with poly(NIPAAm) brushes mainly grafted on surface, whereas H{sub PEG}-G-poly(NIPAAm) has a gradiently decreased poly(NIPAAm) brushes in their chain length from surface to inside. On the other hand, poly(NIPAAm) brushes in H{sub PEG}-U-poly(NIPAAm) are uniformly dispersed throughout the whole hydrogel network. Successful preparation of H{sub PEG}-S-poly(NIPAAm), H{sub PEG}-G-poly(NIPAAm) and H{sub PEG}-U-poly(NIPAAm) were ascertained by X-ray photoelectron spectroscopy (XPS) and water contact angle measurement. Hence, the flexibility and controllability of the synthetic strategy in varying the distribution of polymer brushes and hydrogel surface properties was demonstrated. Hydrogels with tunable and well-defined 3-dimensional poly(NIPAAm) polymer brushes could be tailor-designed to find potential applications in smart devices or skin dressing, such as for diabetics

  13. 75 FR 60643 - Customs and Border Protection Officer Retirement (United States)


    ...; ] OFFICE OF PERSONNEL MANAGEMENT 5 CFR Parts 831, 841, and 842 RIN 3206-AL69 Customs and Border Protection... available to customs and border protection officers under the Civil Service Retirement System (CSRS) and the... Act provides early retirement and enhanced annuity benefits for customs and border protection...

  14. 78 FR 35044 - U.S. Customs and Border Protection (United States)


    ... SECURITY U.S. Customs and Border Protection Agency Information Collection Activities: Visa Waiver Program Carrier Agreement (CBP Form I-775) AGENCY: U.S. Customs and Border Protection, Department of Homeland...: 1651-0110. SUMMARY: U.S. Customs and Border Protection (CBP) of the Department of Homeland...

  15. 75 FR 266 - Customs and Border Protection's Bond Program (United States)


    ...] [FR Doc No: E9-30920] DEPARTMENT OF HOMELAND SECURITY Bureau of Customs and Border Protection DEPARTMENT OF THE TREASURY 19 CFR Parts 101, 113, and 133 [Docket No. USCBP-2006-0013] RIN 1505-AB54 Customs and Border Protection's Bond Program AGENCIES: Customs and Border Protection, Department of...

  16. 77 FR 1497 - U.S. Customs and Border Protection (United States)


    ... SECURITY U.S. Customs and Border Protection Agency Information Collection Activities: Application for Withdrawal of Bonded Stores for Fishing Vessels and Certificate of Use AGENCY: U.S. Customs and Border... comments to U.S. Customs and Border Protection, Attn: Tracey Denning, Regulations and Rulings, Office...

  17. The Dutch-French Language Border in Belgium. (United States)

    Willemyns, Roland


    Describes language border fluctuations in Belgium as far as its Dutch-French portion is concerned. Examines the status and function of the language border in Belgium and of actual border fluctuations. Discusses two problem areas in detail: the "Voerstreek, and the Brussels suburban region. Language shift and language change through erosion in…

  18. Imagining and Imaging Borders: Understanding Borderlands for Global Sustainability (United States)

    Konrad, V.


    Borders are increasingly complex human responses and social constructions in a world where globalizing forces confront basic human concerns for security and certainty. In an effort to provide a background to assess research directions for imaging borders, this paper explores what we know about borders, and what we do not know well about borders. Borders in globalization are the meeting points of globalizing forces of security, trade and migration flows with emerging technologies, self determination and regionalization around the world. We need to know more about how: self determination fuels secessions and new borders; borders result from complex rather than simple policy and governance issues; borders depend on the political clout of borderland communities; market and migration flows impact borders; and borders are always in motion. The paper shows how these organizing principles underlie the basic themes of border governance, flows, culture, history, security and sustainability. Finally, the paper offers two brief illustrations of border imaging to link this presentation to the following discussion of the workshop.

  19. U.S. Border Patrol Fiscal Year Statistics Southwest border sector deaths - FY 1998 through FY 2013 (United States)

    Department of Homeland Security — Southwest Border Sectors include: Del Rio, El Centro, El Paso, Laredo, Rio Grande Valley, San Diego, Tucson, Yuma Southwest Border Deaths By Fiscal Year (Oct. 1st...

  20. Self-assembled alignment of nanorod by using DNA brush (Conference Presentation) (United States)

    Ijiro, Kuniharu; Nakamura, Satoshi; Mitomo, Hideyuki; Pike, Andrew; Matsuo, Yasutaka; Niikura, Kenichi


    Surface modification with polymer is widely applied to various kinds of applications. Recently, polymer brushes, which is a layer of polymers attached with one end to a surface, have attracted much attention as functionalized surfaces. In particular, ionic polymer brushes provide ultra-low friction or anti-fouling because they act as highly hydrated soft film. Almost ionic polymer brushes have been prepared from synthetic polymers. Few biopolymers have been investigated for polymer brush studies. DNA which is one of ionic biopolymers has unique functions and conformations which synthetic polymers don't have. We found that cationic gold nanorods (30 x 10 nm) were adsorbed to DNA bush (148 bp) prepared on a glass surface in an aqueous solution by observation using extinction spectra. When the cationic charge density of gold nanorods were decreased, nanorods were immobilized perpendicularly to the substrate by binding to DNA elongated. This indicates that self-assembled alignment of gold nanorods can be achieved by using DNA brush. Formed aligned gold nanorods can be used for plasmonic color analysis.

  1. Profilometric analysis of two composite resins′ surface repolished after tooth brush abrasion with three polishing systems

    Directory of Open Access Journals (Sweden)

    Mudit Uppal


    Full Text Available Aim: To evaluate the effect of three polishing protocols that could be implemented at recall on the surface roughness of two direct esthetic restorative materials. Materials and Methods: Specimens (n = 40 measuring 8 mm (length × 5 mm (width × 4 mm (height were fabricated in an acrylic mold using two light-cured resin-based materials (microfilled composite and microhybrid composite. After photopolymerization, all specimens were finished and polished with one of three polishing protocols (Enhance, One Gloss, and Sof-Lex polishing systems. The average surface roughness of each treated specimen was determined using 3D optical profilometer. Next all specimens were brushed 60,000 times with nylon bristles at 7200 rpm using crosshead brushing device with equal parts of toothpaste and water used as abrasive medium. The surface roughness of each specimen was measured after brushing followed by repolishing with one of three polishing protocols, and then, the final surface roughness values were determined. Results: The data were analyzed using one-way and two-factor analysis of variance (ANOVA and Tukey′s honestly significant difference (HSD. Significant difference (P < 0.05 in surface roughness was observed. Simulated brushing following initial polishing procedure significantly roughened the surface of restorative material (P < 0.05. Conclusion: Polishing protocols can be used to restore a smooth surface on esthetic restorative materials following simulated tooth brushing.

  2. Experimental determination of optimum gutter brush parameters and road sweeping criteria for different types of waste. (United States)

    Abdel-Wahab, Magd M; Wang, Chong; Vanegas-Useche, Libardo V; Parker, Graham A


    The removal ability of gutter brushes for road sweeping for various debris types and different sweeping parameters is studied through experimental tests. The brushing test rig used comprises two commercial gutter brushes, a concrete test bed, and an asphalt test road with a gutter of 0.25 cm width and 10° slope. The brush-surface contact area is determined by sweeping sand on the concrete test bed. Sweeping problems are identified and discussed, and sweeping criteria for the different debris types are suggested. Also, optimum sweeping parameters are proposed for each debris type. In addition, debris removal mechanisms are discussed and analysed. The results indicate that for large heavy debris such as stones and gravel, it is not difficult to achieve large removal forces, because the steel bristles are relatively stiff. Conversely, high removal forces are not needed for particles of millimetre or micron sizes, but bristle curvature has to be appropriate to remove particles from road concavities. Finally, it is found that mud, especially dry mud on a rough surface, is the hardest debris to sweep, requiring a brush with a large tilt angle and a very large penetration to produce large removal forces.

  3. Static and dynamic properties of polymer brush with topological ring structures: Molecular dynamic simulation (United States)

    Wan, Wu-Bing; Lv, Hong-Hong; Merlitz, Holger; Wu, Chen-Xu


    By defining a topological constraint value (rn), the static and dynamic properties of a polymer brush composed of moderate or short chains with different topological ring structures are studied using molecular dynamics simulation, and a comparison with those of linear polymer brush is also made. For the center-of-mass height of the ring polymer brush scaled by chain length h ˜ N ν , there is no significant difference of exponent from that of a linear brush in the small topological constraint regime. However, as the topological constraint becomes stronger, one obtains a smaller exponent. It is found that there exists a master scaling power law of the total stretching energy scaled by chain length N for moderate chain length regime, F ene ˜ Nρ ν , for ring polymer brushes, but with a larger exponent ν than 5/6, indicating an influence of topological constraint to the dynamic properties of the system. A topological invariant of free energy scaled by 5/4 is found. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374243 and 11574256).

  4. Brushes of semiflexible polymers in equilibrium and under flow in super-hydrophobic regime

    CERN Document Server

    Speyer, Kevin


    We performed molecular dynamics simulations to study equilibrium and flow properties of a liquid in a nano-channel with confining surfaces coated with a layer of grafted semiflexible polymers. The coverage spans a wide range of grafting densities from essentially isolated chains to dense brushes. The end-grafted polymers were described by a bead spring model with an harmonic potential to include the bond stiffness of the chains. We varied the rigidity of the chains, from fully flexible polymers to rigid rods, in which the configurational entropy of the chains is negligible. The brush-liquid interaction was tuned to obtain a super-hydrophobic channel, in which the liquid did not penetrate the polymer brush, giving rise to a Cassie-Baxter state. Equilibrium properties such us brush height and bending energy were measured, varying the grafting density and the stiffness of the polymers. We studied also the characteristics of the brush-liquid interface and the morphology of the polymers chains supporting the liqui...

  5. In Situ Infrared Ellipsometry for Protein Adsorption Studies on Ultrathin Smart Polymer Brushes in Aqueous Environment. (United States)

    Kroning, Annika; Furchner, Andreas; Aulich, Dennis; Bittrich, Eva; Rauch, Sebastian; Uhlmann, Petra; Eichhorn, Klaus-Jochen; Seeber, Michael; Luzinov, Igor; Kilbey, S Michael; Lokitz, Bradley S; Minko, Sergiy; Hinrichs, Karsten


    The protein-adsorbing and -repelling properties of various smart nanometer-thin polymer brushes containing poly(N-isopropylacrylamide) and poly(acrylic acid) with high potential for biosensing and biomedical applications are studied by in situ infrared-spectroscopic ellipsometry (IRSE). IRSE is a highly sensitive nondestructive technique that allows protein adsorption on polymer brushes to be investigated in an aqueous environment as external stimuli, such as temperature and pH, are varied. These changes are relevant to conditions for regulation of protein adsorption and desorption for biotechnology, biocatalysis, and bioanalytical applications. Here brushes are used as model surfaces for controlling protein adsorption of human serum albumin and human fibrinogen. The important finding of this work is that IRSE in the in situ experiments in protein solutions can distinguish between contributions of polymer brushes and proteins. The vibrational bands of the polymers provide insights into the hydration state of the brushes, whereas the protein-specific amide bands are related to changes of the protein secondary structure.

  6. Efficient spin-coating-free planar heterojunction perovskite solar cells fabricated with successive brush-painting (United States)

    Lee, Jin-Won; Na, Seok-In; Kim, Seok-Soon


    To demonstrate fully brush-painted planar heterojunction perovskite solar cells (PeSCs), poly (3,4-ethylendioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) hole transport layer (HTL), CH3NH3PbI3 perovskite photoactive layer, and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) electron acceptor layer are successively brush-painted. In particular, correlation between morphology of perovskites and overall performance of PeSCs are investigated depending on the perovskites precursor. Devices with brush-painted perovskite using generally used N,N-dimethylformamide (DMF) solvent show poor performance and large deviation in cell-performance. However, PeSCs with brush-painted perovskite employing protic 2-Methoxyethanol (2-M) as DMF-alternative solvent exhibit comparable power conversion efficiency (PCE) of 9.08% to conventional spin-coated device and excellent reproducibility in device performance is observed as well. Furthermore, a fully brush-painted PeSC based on flexible substrates, showing PCE of 7.75%, is successfully demonstrated.

  7. The border between the central and the peripheral nervous system in the cat cochlear nerve: a light and scanning electron microscopical study. (United States)

    Osen, Kirsten K; Furness, David N; Hackney, Carole M


    The transition between the central (CNS) and peripheral nervous system (PNS) in cranial and spinal nerve roots, referred to here as the CNS-PNS border, is of relevance to nerve root disorders and factors that affect peripheral-central regeneration. Here, this border is described in the cat cochlear nerve using light microscopical sections, and scanning electron microscopy of the CNS-PNS interfaces exposed by fracture of the nerve either prior to or following critical point drying. The CNS-PNS border represents an abrupt change in type of myelin, supporting elements, and vascularization. Because central myelin is formed by oligodendrocytes and peripheral myelin by Schwann cells, the myelinated fibers are as a rule equipped with a node of Ranvier at the border passage. The border is shallower and smoother in cat cochlear nerve than expected from other nerves, and the borderline nodes are largely in register. The loose endoneurial connective tissue of the PNS compartment is closed at the border by a compact glial membrane, the mantle zone, of the CNS compartment. The mantle zone is penetrated by the nerve fibers, but is otherwise composed of astrocytes and their interwoven processes like the external limiting membrane of the brain surface with which it is continuous. The distal surface of the mantle zone is covered by a fenestrated basal lamina. Only occasional vessels traverse the border. From an anatomical point of view, the border might be expected to be a weak point along the cochlear nerve and thus vulnerable to trauma. In mature animals, the CNS-PNS border presents a barrier to regrowth of regenerating nerve fibers and to invasion of the CNS by Schwann cells. An understanding of this region in the cochlear nerve is therefore relevant to head injuries that lead to hearing loss, to surgery on acoustic Schwannomas, and to the possibility of cochlear nerve regeneration.

  8. The Nature and Functions of European Political Borders

    Directory of Open Access Journals (Sweden)

    Jernej Zupančič


    Full Text Available The political border limits a state’s territory and symbolizes the extent of a state’s power and ownership. Borders give integrity to the inner state territory which they enclose (the role of establishing national integrity and at the same time form an outer boundary segregating the state territory from the surrounding politicial entities (the segregation role. European borders are old and reflect the political history of an old continent. The last major border changes happened after World War II. Over the centuries borders were merely lines separating one territory from another. Such borders were understood as »frontiers«. Forming an effective barrier against enemies was the overriding function of borders. Many borders were fortified and further enhanced by means of various defensive systems. In the second half of the 20th century the character of political borders changed. They became a contact area between countries, nations and cultures. Contemporary European borders reflect the colourful history of an old continent. They are predominantely functional markers: they represent the political and juridical delimitation of territories, they mark economic barriers and show their defensive nature and reveal the extent of cultural contact. As a result of European integration processes, the nature of political borders has changed: instead of division, their integration role is brought to the fore. A united Europe is nevertheless still not a borderless Europe! The borders within the »Schengen-area« have retained their political and administrative functions, it is just that the customs and security checks at the borders have been removed. During the period of European integration, borderlines were stabilized in accordance with the 1974 Helsinki Agreement. But despite this we can still observe ongoing changes to state borders, particularly in areas of conflict such as the Balkan peninsula. It seems after all that the process of demarcation

  9. Off-shoring and out-sourcing the borders of EUrope: Libya and EU border work in the Mediterranean

    NARCIS (Netherlands)

    Bialasiewicz, L.


    The article examines some of the novel ways in which the European Union carries out its ‘border-work’- border-work that stretches far beyond the external borders of the current Union. It highlights, in particular, the role of EUrope's neighbours in new strategies of securitisation, drawing attention

  10. Opportunities for Cross-Border Entrepreneurship Development in a Cluster Model Exemplified by the Polish–Czech Border Region

    Directory of Open Access Journals (Sweden)

    Joanna Kurowska-Pysz


    Full Text Available The subject of the paper is the analysis and evaluation of cross-border entrepreneurship development opportunities on the basis of cross-border cooperation, which has gradually evolved from consisting of bilateral partnerships to a networking model or even a cluster. The study conducted at the Polish–Czech border area indicates that, in terms of the development of cross-border cooperation, the economic sphere is lagging far behind social activities such as culture, education and tourism. At the same time, Polish and Czech enterprises are not sufficiently mobilized to develop cross-border entrepreneurship, although a number of support instruments in this regard have been proposed. Sustainable development of the border should take into account both social and economic aspects. An important research problem therefore becomes determining the possibility of boosting the development of cross-border entrepreneurship on the basis of the existing forms of cross-border cooperation, including cooperation in the social sphere. The aim of this paper is to define the conditions and opportunities for the development of cluster cooperation in the area of cross-border entrepreneurship. The author has attempted to resolve whether the intensity of cross-border cooperation can be a factor which mobilizes companies to develop their cross-border entrepreneurship and whether cross-border entrepreneurship can be further developed within the cluster model.

  11. Centronuclear myopathy in a Border collie dog. (United States)

    Eminaga, S; Cherubini, G B; Shelton, G D


    A two-year old, male entire Border collie was presented with a one-year history of exercise-induced collapsing on the pelvic limbs. Physical examination revealed generalised muscle atrophy. Neurological examination supported a generalised neuromuscular disorder. Electromyography revealed spontaneous electrical activity in almost all muscles. Unfixed and formaldehyde-fixed biopsy samples were collected from the triceps brachii, longissimus and vastus lateralis muscles. Histopathological, histochemical and ultrastructural examinations of biopsy specimens were consistent with either centronuclear or myotubular myopathy. The dog clinically improved with supportive treatment with L-carnitine, co-enzyme Q10 and vitamin B compound. To the authors' knowledge, this is the first report of centronuclear/myotubular myopathy in a Border collie.

  12. Structural specificity of mucosal-cell transport and metabolism of peptide drugs: implication for oral peptide drug delivery (United States)

    Bai, J. P.; Amidon, G. L.


    The brush border membrane of intestinal mucosal cells contains a peptide carrier system with rather broad substrate specificity and various endo- and exopeptidase activities. Small peptide (di-/tripeptide)-type drugs with or without an N-terminal alpha-amino group, including beta-lactam antibiotics and angiotensin-converting enzyme (ACE) inhibitors, are transported by the peptide transporter. Polypeptide drugs are hydrolyzed by brush border membrane proteolytic enzymes to di-/tripeptides and amino acids. Therefore, while the intestinal brush border membrane has a carrier system facilitating the absorption of di-/tripeptide drugs, it is a major barrier limiting oral availability of polypeptide drugs. In this paper, the specificity of peptide transport and metabolism in the intestinal brush border membrane is reviewed.

  13. Moment matrices, border bases and radical computation


    Mourrain, B.; J. B. Lasserre; Laurent, Monique; Rostalski, P.; Trebuchet, Philippe


    In this paper, we describe new methods to compute the radical (resp. real radical) of an ideal, assuming it complex (resp. real) variety is nte. The aim is to combine approaches for solving a system of polynomial equations with dual methods which involve moment matrices and semi-denite programming. While the border basis algorithms of [17] are ecient and numerically stable for computing complex roots, algorithms based on moment matrices [12] allow the incorporation of additional polynomials, ...

  14. Effective Border Tax Adjustments for Export Promotion


    Glenn P. Jenkins; Chun-Yan Kuo


    In this paper, we address the administration issues associated with the most important border tax adjustments for export expansion. These relate to the refund of input tax credits under the VAT and the relief from customs duties on imported inputs used to produce exports. Such refunds in many developing countries are either not paid in a timely fashion or have been fraudulently overstated in the claims made by exporters. These become impediments that have frequently discouraged foreign invest...

  15. Streaming Potential and Energy Conversion in Nanochannel Grafted With Poly-Zwitterion Brushes (United States)

    Patwary, Jahin; Chen, Guang; Das, Siddhartha


    Here we study the streaming potential and electrochemomechanical energy conversion in nanochannels grafted with poly-zwitterion (PZ) brushes. PZs are polymer molecules consisting of negative and positive charge centres simultaneously; depending on the bulk pH, the extent of dissociation differs at each of these charge centres, yielding a particular net charge on the PZ molecule. This PZ charge, therefore, develops a pH dependent electrostatics of the PZ brushes grafted at the naochannel walls. We develop a self-consistent field theory model to calculate this electrostatics by appropriately accounting for the explicit hydrogen ion concentration. Secondly, we use this electrostatics to calculate the streaming potential and the resulting electrochemomechanical energy conversion in nanochannels grafted with poly-zwitterion (PZ) brushes. Our results indicate distinct influences of pH, bulk ion concentration, and the ionization parameters of the PZs in regulating the nanochannel energy conversion. Bridge to the Doctorate Fellowship - LSAMP Committee.

  16. Grafting amphiphilic brushes onto halloysite nanotubes via a living RAFT polymerization and their Pickering emulsification behavior. (United States)

    Hou, Yifan; Jiang, Junqing; Li, Kai; Zhang, Yanwu; Liu, Jindun


    Amphiphilic brushes of poly(4-vinylpyridine)-block-polystyrene (P4VP-b-PS) and polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) are grafted onto halloysite nanotubes (HNTs) via a surface reversible addition-fragmentation chain transfer (RAFT) living polymerization through anchoring R group in RAFT agent S-1-dodecyl-S'-(R,R'-dimethyl-R″-acetic acid) trithiocarbonates (DDMAT). The characterization of TGA, TEM, and GPC show that amphiphilic brushes are successfully grafted onto HNTs in a living manner. To verify the amphiphilicity of HNTs grafted with block copolymers, their Pickering emulsification behavior in water/soybean oil diphase mixture is studied. The results show that modified HNTs can emulsify water/soybean oil diphase mixture and the emulsification performance is dependent on microstructure of amphiphilic brushes such as hydrophilic/hydrophobic segment size and sequence.

  17. Nanostructure of Cationic Polymer Brush at the Air/Water Interface

    Directory of Open Access Journals (Sweden)

    Matsuoka Hideki


    Full Text Available Cationic amphiphilic diblock copolymers were synthesized by RAFT polymerization and the nanostructure of their monolayers was investigated by π-A isotherm and X-ray reflectivity. Carpet layer (dense hydrophilic block layer formation under the hydrophobic layer was confirmed and a “brush” layer was found beneath the carpet layer. However, the thickness of brush layer was much thinner than that of the fully-stretched chain length. The critical salt concentration was found to be 0.01 M NaCl, which is much lower than that of the previous strongly anionic brush. These differences were probably caused by the low effective charge on the brush chains due to the hydrophobic nature of the quarternized ammonium cation.

  18. Brushing Your Spacecrafts Teeth: A Review of Biological Reduction Processes for Planetary Protection Missions (United States)

    Pugel, D.E. (Betsy); Rummel, J. D.; Conley, C. A.


    Much like keeping your teeth clean, where you brush away biofilms that your dentist calls plaque, there are various methods to clean spaceflight hardware of biological contamination, known as biological reduction processes. Different approaches clean your hardwares teeth in different ways and with different levels of effectiveness. We know that brushing at home with a simple toothbrush is convenient and has a different level of impact vs. getting your teeth cleaned at the dentist. In the same way, there are some approaches to biological reduction that may require simple tools or more complex implementation approaches (think about sonicating or just soaking your dentures, vs. brushing them). There are also some that are more effective for different degrees of cleanliness and still some that have materials compatibility concerns. In this article, we review known and NASA-certified approaches for biological reduction, pointing out materials compatibility concerns and areas where additional research is needed.

  19. A PET activation study of brush-evoked allodynia in patients with nerve injury pain

    DEFF Research Database (Denmark)

    Witting, Nanna; Kupers, Ron; Svensson, Peter;


    in the cortical network involved in the sensory-discriminative processing of nociceptive pain is downregulated in neuropathic pain. Instead, there is an upregulation of activity in the orbitofrontal and insular cortices, which is probably due to the stronger emotional load of neuropathic pain and higher......Acute experimental brush-evoked allodynia induces a cortical activation pattern that differs from that typically seen during experimental nociceptive pain. In this study, we used positron emission tomography to measure changes in regional cerebral blood flow (rCBF) in patients with clinical....... A direct post hoc comparison of brush -and allodynia-induced rCBF changes showed that allodynia was associated with significantly stronger activations in orbitofrontal cortex and ipsilateral insula whereas non-painful brushing more strongly activated SI and BA 5/7. These findings indicate that activity...

  20. Polymer brushes interfacing blood as a route toward high performance blood contacting devices. (United States)

    Surman, František; Riedel, Tomáš; Bruns, Michael; Kostina, Nina Yu; Sedláková, Zdeňka; Rodriguez-Emmenegger, Cesar


    In the current study, well-defined polymer brushes are shown as an effective surface modification to resist the adhesion of whole blood and its components. Poly[oligo(ethylene glycol)methylether methacrylate] (poly(MeOEGMA)), poly(hydroxyethyl methacrylate) (poly(HEMA)), poly[N-(2-hydroxypropyl) methacrylamide] (poly(HPMA)), and poly(carboxybetaine acrylamide) (poly(CBAA)) brushes were grown by surface initiated atom transfer radical polymerization (SI-ATRP) and subsequently characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), dynamic contact angle measurements, atomic force microscopy (AFM), and surface plasmon resonance (SPR) spectroscopy. All brushes decreased the fouling from blood plasma over 95% and prevented the adhesion of platelets, erythrocytes, and leukocytes as evidenced by SPR and SEM measurements.

  1. Inhibitory effect for proliferation of oral bacteria in dogs by tooth brushing and application of toothpaste (United States)

    WATANABE, Kazuhiro; KIJIMA, Saku; NONAKA, Chie; MATSUKAWA, Yuki; YAMAZOE, Kazuaki


    To investigate inhibitory effect for oral bacterial proliferation, we divided 12 dogs into 3 groups; scaling alone (C; control group), brushing (B) and application of toothpaste (P). Before scaling (Pre) and at 0 to 8 weeks after scaling (0–8 w), we collected oral bacteria from the dental surface every week and counted them using a bacterial counter. The results demonstrated a significant reduction in the number of oral bacteria for group B relative to Pre and group C, as well as for group P relative to group C at 5–7 w. Consequently, brushing may inhibit an increase in the number of oral bacteria, and toothpaste may be effective at a certain level, although not more than that of brushing. PMID:27062999

  2. Insight into the electrical properties and chain conformation of spherical polyelectrolyte brushes by dielectric spectroscopy (United States)

    Guo, Xiaoxia; Zhao, Kongshuang


    We report here a dielectric study on three kinds of anionic spherical polyelectrolyte brush (SPBs, consisting of a polystyrene (PS) core and three different poly (acrylic acid) chains grafted onto the core) suspensions over a frequency ranging from 40 Hz to 110 MHz. The relaxation behavior of the SPB suspensions shows significant changes in the brush-layer properties when the mass fraction of SPBs and the pH of the suspensions change. Two definite relaxations related to the interfacial polarization are observed around 100 kHz and 10 MHz. A single-layer spherical-shell model is applied to describe the SPB suspensions wherein the suspended SPB is modeled as a spherical-shell composite particle in which an insulated PS sphere is surrounded by a conducting ion-permeable shell (the polyelectrolyte chain layer). We developed the curve-fitting procedure to analyze the dielectric spectrum in order to obtain the dielectric properties of the components of the SPBs, especially the properties of the polyelectrolyte brush. Based on this method and model, the permittivity and conductivity of the brush layer, ζ potential, etc are calculated. The ordered orientation of the water molecules in the layer leads to an additional electrical dipole moment; increasing pH causes the brush layer to swell. In addition, the repulsive force between the SPB particles are evaluated using the brush-layer thickness, which is obtained by fitting dielectric spectra, combined with relative theoretical formulas. Increasing PH values or SPB concentration would improve the stability of the SPBs dispersion.

  3. Efficacy of three denture brushes on biofilm removal from complete dentures

    Directory of Open Access Journals (Sweden)

    Roseana Aparecida Gomes Fermandes


    Full Text Available The aim of this study was to compare the efficacy of three denture brushes (Bitufo-B; Medic Denture-MD; Colgate-C on biofilm removal from upper and lower dentures using a specific dentifrice (Corega Brite. The correlation between biofilm levels on the internal and external surfaces of the upper and lower dentures was also evaluated. A microbiological assay was performed to assess the growth of colony-formed units (cfu of Candida yeasts on denture surface. Thirty-three patients were enrolled in a 10-week trial divided in two stages: 1 (control - three daily water rinses within 1 week; 2 - three daily brushings within 3 weeks per tested brush. Internal (tissue and external (right buccal flange surfaces of the complete dentures were disclosed (neutral red 1% and photographed. Total denture areas and disclosed biofilm areas were measured using Image Tool 3.00 software for biofilm quantification. Dentures were boxed with #7 wax and culture medium (CHROMagarTM Candida was poured to reproduce the internal surface. Statistical analysis by Friedman's test showed significant difference (p0.01. Analysis by the Correlation test showed higher r values (B=0.78; MD=0.8341, C=0.7362 for the lower dentures comparing the surfaces (internal and external and higher r values (B=0.7861, MD=0.7955, C=0.8298 for the external surface comparing the dentures (upper and lower. The results of the microbiological showed no significant difference (p>0.01 between the brushes with respect to the frequency of the species of yeasts (chi-square test. In conclusion, all denture brushes evaluated in this study were effective in the removal of biofilm. There was better correlation of biofilm levels between the surfaces for the lower dentures, and between the dentures for the external surface. There was no significant difference among the brushes regarding the frequency of yeasts.

  4. Fatigue life improvements of the AISI 304 stainless steel ground surfaces by wire brushing (United States)

    Ben Fredj, Nabil; Ben Nasr, Mohamed; Ben Rhouma, Amir; Sidhom, Habib; Braham, Chedly


    The surface and subsurface integrity of metallic ground components is usually characterized by an induced tensile residual stress, which has a detrimental effect on the fatigue life of these components. In particular, it tends to accelerate the initiation and growth of the fatigue cracks. In this investigation, to deliberately generate compressive residual stresses into the ground surfaces of the AISI 304 stainless steel (SS), wire brushing was applied. It was found that under the experimental conditions selected in this investigation, while the surface roughness was slightly improved by the brushing process, the surface residual stress shifted from a tensile stress (σ‖=+450 MPa) to a compressive stress (σ‖=-435 MPa). On the other hand, the work-hardened deformation layer was almost two times deeper after wire brushing. Concerning the fatigue life, an improvement of 26% in terms of endurance limit at 2×106 cycles was realized. Scanning electron microscope (SEM) observations of the fatigue fracture location and size were carried out to explain the fatigue life improvement. It was found that the enhancement of the fatigue strength could be correlated with the distribution and location of the fatigue fracture nucleation sites. Concerning the ground surfaces, it was seen that the fatigue cracks initiated at the bottom of the grinding grooves and were particularly long (150-200 µm). However, the fatigue cracks at the brushed surfaces were shorter (20-40 µm) and appeared to initiate sideways to the plowed material caused by the wire brushing. The results of the wire-brushed surface characterization have shown that significant advantages can be realized regarding surface integrity by the application of this low-cost process compared to shot peening.

  5. Detection of Fungi in Hair-brushes in Beauty Salons at Jatinangor

    Directory of Open Access Journals (Sweden)

    Susanna Mitchelle Edward


    Full Text Available Background: Various beauty tools are used in beauty salons, among those is the hair-brush. The hair-brush can conceal various human skin pathogens although under harsh environmental conditions, most pathogens are killed; nevertheless, few microorganisms, such as the fungi can adapt and survive. Moreover, the moist conditions of the hair-brush predisposes the growth of fungi however the ability of these fungi to instigate disease in an individual is dependent on the portal of entry and the host immunological status. This study was conducted to determine the fungus that is present in the beauty salon’s hair-brushes. Methods: This study was conducted in beauty salons located in Jatinangor area during September–October 2013 using the descriptive laboratory method. Fifteen beauty salons were included in this study based on sample size calculation for dichotomous variable. The specimens from all the hair-brushes were collected after the owner’s informed consent, then cultured onto 30 sabouraud agar, two for each beauty salon (dermatophyte and non-dermatophyte agar. The fungi were detected macroscopically and microscopically. Results: Overall, 93% revealed to be culture positive, with 90% of them were found to be non-dermatophytes, most of which are saprophytic fungi. The remaining 3% were dermatophytes. Conclusions: Beauty salon’s hair-brushes contain a wide range of fungi distribution which may be a source of fungal colonization. However, most of the fungi found in the beauty salons are saprophytic fungi, therefore it is unnecessary to be anxious about a small amount of pathogenic fungi are found in humans.

  6. Non-biofouling property of well-defined concentrated polymer brushes. (United States)

    Yoshikawa, Chiaki; Qiu, Jun; Huang, Chih-Feng; Shimizu, Yoshihisa; Suzuki, Junji; van den Bosch, Edith


    The non-biofouling properties of polymer brushes of poly(2-hydroxyethyl methacrylate) (PHEMA), poly(2-hydroxyethyl acrylate) (PHEA), and poly(poly(ethylene glycol) methyl ether methacrylate) (PPEGMA) were comprehensively studied by varying graft densities (i.e., semi-dilute and concentrated regimes) and the thicknesses at the dry state of 2 and 10 nm. Semi-dilute polymer brushes (SDPBs) were prepared by grafting-to method and concentrated polymer brushes (CPBs) were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). The adsorptions of proteins with different sizes were investigated on the brushes by quartz crystal microbalance (QCM) from a view point of size-exclusion effect specific to the CPBs. We confirmed that due to the size exclusion effect, the CPBs of all the three much suppressed proteins adsorption and human umbilical vein endothelial cell (HUVEC) adhesion compared with the corresponding SDPBs. In order to investigate what type of proteins adsorbed on the brushes to trigger cell adhesion, we identified adsorbed proteins from fetal bovine serum on the brushes using a high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Proteins were only detected on the SDPBs. Interestingly, the number and type of identified proteins were different on the SDPBs, indicating that chemical composition of the SDPBs affects protein adsorption, hence the cell adhesion. The adsorption mechanism on the SDPBs could be due to the combination of protein-polymer interaction and physical inclusion, whereas CPBs exhibit size exclusion effect combined with neutral hydrophilic nature of polymer, thereby, that provides excellent non-biofouling property.

  7. Auditory stimuli mimicking ambient sounds drive temporal "delta-brushes" in premature infants.

    Directory of Open Access Journals (Sweden)

    Mathilde Chipaux

    Full Text Available In the premature infant, somatosensory and visual stimuli trigger an immature electroencephalographic (EEG pattern, "delta-brushes," in the corresponding sensory cortical areas. Whether auditory stimuli evoke delta-brushes in the premature auditory cortex has not been reported. Here, responses to auditory stimuli were studied in 46 premature infants without neurologic risk aged 31 to 38 postmenstrual weeks (PMW during routine EEG recording. Stimuli consisted of either low-volume technogenic "clicks" near the background noise level of the neonatal care unit, or a human voice at conversational sound level. Stimuli were administrated pseudo-randomly during quiet and active sleep. In another protocol, the cortical response to a composite stimulus ("click" and voice was manually triggered during EEG hypoactive periods of quiet sleep. Cortical responses were analyzed by event detection, power frequency analysis and stimulus locked averaging. Before 34 PMW, both voice and "click" stimuli evoked cortical responses with similar frequency-power topographic characteristics, namely a temporal negative slow-wave and rapid oscillations similar to spontaneous delta-brushes. Responses to composite stimuli also showed a maximal frequency-power increase in temporal areas before 35 PMW. From 34 PMW the topography of responses in quiet sleep was different for "click" and voice stimuli: responses to "clicks" became diffuse but responses to voice remained limited to temporal areas. After the age of 35 PMW auditory evoked delta-brushes progressively disappeared and were replaced by a low amplitude response in the same location. Our data show that auditory stimuli mimicking ambient sounds efficiently evoke delta-brushes in temporal areas in the premature infant before 35 PMW. Along with findings in other sensory modalities (visual and somatosensory, these findings suggest that sensory driven delta-brushes represent a ubiquitous feature of the human sensory cortex

  8. Changing European borders: from separation to interface? An introduction

    Directory of Open Access Journals (Sweden)

    Jen Nelles


    Full Text Available The aim of this special issue is to address the evolution of European borders from a comparative perspective. This collection of papers spans a wide variety of topics in the realm of borderland studies. Although each engages with a single empirical or theoretical case collectively they identify nuances relevant to the theoretical elaboration of borders, and particularly contribute to the field of sub-national cross-border cooperation. In the course of its analysis each paper contributes to a broader understanding of the definition of cross-border regions; identifies a set of barriers to cooperation in these contexts; explores the role of identities on cooperation and of the role of borders in constructing those identities; and reflects on the socio-political meanings and uses of these international boundaries. This introduction discusses theoretical significance of these contributions to major debates in the study of borders and border regions.

  9. Examining Scientific and Technical Writing Strategies in the 11th Century Chinese Science Book "Brush Talks from Dream Brook" (United States)

    Zhang, Yuejiao


    This article examines the influential Chinese science book "Brush Talks from Dream Brook," written by Shen Kuo in the 11th century. I suggest that "Brush Talks" reveals a tension between institutionalized science and science in the public, and a gap between the making of scientific knowledge and the communication of such…

  10. Spatial inhomogeneity in spectra and exciton dynamics in porphyrin micro-rods and micro-brushes: Confocal microscopy

    Indian Academy of Sciences (India)



    In an aqueous acidic solution, the porphyrin meso-tetra(4-sulfonatophenyl) porphyrin tetrasodium salt (TPPS) forms different kinds of assembly (micro-rods and micro-brush) depending on condition of evaporation. The exciton dynamics and emission spectra of the micro-rods and micro-brushes depend on spatialinhomogeneity. This is elucidated by time-resolved confocal microscopy.

  11. Fundamental and Applied Studies of Polymer Membranes (United States)

    Imbrogno, Joseph

    Four major areas have been studied in this research: 1) synthesizing novel monomers, e.g. chiral monomers, to produce new types of functionalized membranes for the biotechnology and pharmaceutical industries, 2) hydrophobic brush membranes for desalinating brackish water, sea water, and separating organics, 3) fundamental studies of water interactions at surfaces using sum frequency generation (SFG), and 4) discovering new surface chemistries that will control the growth and differentiation of stem cells. We have developed a novel synthesis method in order to increase the breadth of our high throughput screening library. This library was generated using maleimide chemistry to react a common methacrylate linker with a variety of different functions groups (R groups) in order to form new monomers that were grafted from the surface of PES ultrafiltration membranes. From this work, we discovered that the chirality of a membrane can affect performance when separating chiral feed streams. This effect was observed when filtering bovine serum albumin (BSA) and ovalbumin in a high salt phosphate buffered saline (PBS, 150 mM salt). The Phe grafted membranes showed a large difference in performance when filtering BSA with selectivity of 1.13 and 1.00 for (S) and (R) Phe, respectively. However, when filtering ovalbumin, the (S) and (R) modified surfaces showed selectivity of 2.06 and 2.31, respectively. The higher selectivity enantiomer switched for the two different proteins. Permeability when filtering BSA was 3.06 LMH kPa-1 and 4.31 LMH kPa -1 for (S)- and (R)- Phe, respectively, and 2.65 LMH kPa -1 and 2.10 LMH kPa-1 when filtering ovalbumin for (S)- and (R)- Phe, respectively. Additionally, these effects were no longer present when using a low salt phosphate buffer (PB, 10 mM salt). Since, to our knowledge, membrane chirality is not considered in current industrial systems, this discovery could have a large impact on the pharmaceutical and biotechnology industries. We

  12. A corrosion resistant cerium oxide based coating on aluminum alloy 2024 prepared by brush plating

    Energy Technology Data Exchange (ETDEWEB)

    Tang Junlei; Han Zhongzhi [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Zuo Yu, E-mail: [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Tang Yuming [School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)


    Cerium oxide based coatings were prepared on AA2024 Al alloy by brush plating. The characteristic of this technology is that hydrogen peroxide, which usually causes the plating solution to be unstable, is not necessary in the plating electrolyte. The coating showed laminated structures and good adhesive strength with the substrate. X-ray diffraction and X-ray photoelectron spectroscopy analysis showed that the coatings were composed of Ce(III) and Ce(IV) oxides. The brush plated coatings on Al alloys improved corrosion resistance. The influence of plating parameters on structure and corrosion resistance of the cerium oxide based coating was studied.

  13. Low temperature bonding of LD31 aluminum alloys by electric brush plating Ni and Cu coatings

    Institute of Scientific and Technical Information of China (English)

    Zhao Zhenqing; Wang Chunqing; Du Miao


    Soldering of LD31 aluminum alloys using Sn-Pb solder paste after electric brush plating Ni and Cu coatings was nvestigated. The technology of electric brush plating Ni and Cu was studied and plating solution was developed. The microstructure of the coatings, soldered joint and fracture face were analyzed using optic microscopy, SEM and EDX. The shear strength of soldered joint could reach as high as 26. 83 MPa. The results showed that reliable soldered joint could be obtained at 230℃, the adhesion of coatings and LD31 aluminum alloy substrate was high enough to bear the thermal process in the soldering.

  14. Efficient planar perovskite solar cell by spray and brush solution-processing methods (United States)

    Chilvery, Ashwith Kumar; Guggilla, Padmaja; Batra, Ashok K.; Gaikwad, Dyaneshwar D.; Currie, James R.


    Perovskite compounds have the potential to transform photovoltaics technology, as they are easy to fabricate, have better stability, and possess superior power conversion efficiency. In this research, a versatile solution-processing method called "spray+brush" (SB) has been adopted to achieve a power-conversion efficiency of 3.52% for pure organometal halide perovskite devices. It has been observed that this method is more efficient and cost effective than the perovskite devices fabricated by spray (1.95%) and brush (1.17%) methods alone. The SB method of solution processing can be promising for various other organic coatings.

  15. Polyelectrolyte Properties in Mono and Multi-Valent Ionic Media: Brushes and Complex Coacervates (United States)

    Farina, Robert M.

    Materials composed of polyelectrolytes have unique and interesting physical properties resulting primarily from their charged monomer segments. Polyelectrolytes, which exist in many different biological and industrial forms, have also been shown to be highly responsive to external environmental changes. Here, two specific polyelectrolyte systems, brushes and complex coacervates, are discussed in regards to how their properties can be tailored by adjusting the surrounding ionic environment with mono and multi-valent ions. End-tethered polyelectrolyte brushes, which constitute an interesting and substantial portion of polyelectrolyte applications, are well known for their ability to provide excellent lubrication and low friction when coated onto surfaces (e.g. articular cartilage and medical devices), as well as for their ability to stabilize colloidal particles in solution (e.g. paint and cosmetic materials). These properties have been extensively studied with brushes in pure mono-valent ionic media. However, polyelectrolyte brush interactions with multi-valent ions in solution are much less understood, although highly relevant considering mono and multi-valent counterions are present in most applications. Even at very low concentrations of multi-valent ions in solution, dramatic polyelectrolyte brush physical property changes can occur, resulting in collapsed chains which also adhere to one another via multi-valent bridging. Here, the strong polyelectrolyte poly(sodium styrene sulfonate) was studied using the Surface Forces Apparatus (SFA) and electrochemistry in order to investigate brush height and intermolecular interactions between two brushes as a function of multi-valent counterion population inside a brush. Complex coacervates are formed when polyanions and polycations are mixed together in proper conditions of an aqueous solution. This mixing results in a phase separation of a polymer-rich, coacervate phase composed of a chain network held together via

  16. On writing brush from Xuanzhou in the Tang Dynasty%唐代宣笔考辨

    Institute of Scientific and Technical Information of China (English)



    In the Tang Dynasty, writing brush from Xuanzhou was called violet pekoe pen because of its special manufacturing materials—violet pekoe. Xuancheng Zhuge family made pens for generations, which were all of high quality so as to have won high reputation, thus writing brush from Xuanzhou was also known as Zhuge pen. The violet pekoe pen and Zhuge pen became the representatives of writing brushes from Xuanzhou. Violet pekoe came from the middle mountain in Xuanzhou lishui, rather than from the Zhongshan Country in Han Dynasty. The writing brush from Xuanzhou was made excellent, people who used writing brush from Xuanzhou were very extensive, and evaluation about it was very high. Writing brushes from Xuanzhou were used tribute pen at least in the Tianbao years of Tang Dynasty. As a tribute pen, the writing brush from Xuanzhou had to meet more strict quality requirements. However, through the prosperity of the Tang and Northern Song Dynasties, the writing brush from Xuanzhou was in decline for a variety of reasons.%  唐代宣笔,因其使用特殊的制作材料——紫毫,而被称为紫毫笔;又有宣城诸葛氏世代做笔,且质量较高,远近闻名,因而宣笔又被称为诸葛笔。紫毫笔和诸葛笔成了宣笔的代名词。紫毫出自宣州溧水中山兔,而非汉赵之中山郡兔毫。宣笔的制作十分精良,使用宣笔的人群非常广泛,人们对其评价也很高。宣笔作为贡笔最晚当在唐玄宗天宝年间。作为贡笔的宣笔,在质量上有着更为严格的要求。然而,经历了唐北宋的繁华后,宣笔因种种原因走向衰落。

  17. Small Border Traffic and Cross-Border Tourism Between Poland and the Kaliningrad Oblast of the Russian Federation

    Directory of Open Access Journals (Sweden)

    Anisiewicz Renata


    Full Text Available Polish and Russian cross-border cooperation is governed by lawful agreements. The enlargement of the Schengen Area had a significant impact on Kaliningrad Oblast relations and cross-border cooperation with its neighbours. The introduction of visas between Poland and Russia hindered and restricted local border trade which had for years been the only measure mitigating social and economic problems of the cross-border regions. Nevertheless, border traffic between Poland and Kaliningrad grew steadily, to exceed four million in 2012.

  18. Membranous nephropathy (United States)

    ... page: // Membranous nephropathy To use the sharing features on this page, please enable JavaScript. Membranous nephropathy is a kidney disorder that leads to changes ...

  19. Border Malaria Associated with Multidrug Resistance on Thailand-Myanmar and Thailand-Cambodia Borders: Transmission Dynamic, Vulnerability, and Surveillance

    Directory of Open Access Journals (Sweden)

    Adisak Bhumiratana


    Full Text Available This systematic review elaborates the concepts and impacts of border malaria, particularly on the emergence and spread of Plasmodium falciparum and Plasmodium vivax multidrug resistance (MDR malaria on Thailand-Myanmar and Thailand-Cambodia borders. Border malaria encompasses any complex epidemiological settings of forest-related and forest fringe-related malaria, both regularly occurring in certain transmission areas and manifesting a trend of increased incidence in transmission prone areas along these borders, as the result of interconnections of human settlements and movement activities, cross-border population migrations, ecological changes, vector population dynamics, and multidrug resistance. For regional and global perspectives, this review analyzes and synthesizes the rationales pertaining to transmission dynamics and the vulnerabilities of border malaria that constrain surveillance and control of the world’s most MDR falciparum and vivax malaria on these chaotic borders.

  20. Firing membranes

    NARCIS (Netherlands)

    Kappert, Emiel Jan


    Thermal processing is commonly employed to alter the chemistry and microstructure of membrane layers. It can shape, strengthen, and give functionality to a membrane. A good understanding of the processes taking place during the thermal processing of a membrane material allows for optimization and tu

  1. Miktoarms hyperbranched polymer brushes:One-step fast synthesis by parallel click chemistry and hierarchical self-assembly

    Institute of Scientific and Technical Information of China (English)


    Spherical molecular brushes with amphiphilic heteroarms were facilely synthesized by grafting the arms of hydrophobic 2-azidoethyle palmitate and hydrophilic monoazide-terminated poly(ethylene glycol) onto the core of alkyne-modified hyperbranched polyglycerol (HPG) with high molecular weight (Mn=122 kDa) via one-pot parallel click chemistry.The parallel click grafting strategy was demonstrated to be highly efficient (~100%),very fast (~ 2 h) and well controllable to the amphilicity of molecular brushes.Through adjusting the feeding ratio of hydrophobic and hydrophilic arms,a series of brushes with different arm ratios were readily obtained.The resulting miktoarms hyperbranched polymer brushes (HPG-g-C16/PEG350) were characterized by hydrogen-nuclear magnetic resonance (1H NMR),Fourier transform infrared (FT-IR) spectroscopy,gel permeation chromatography (GPC),and differential scanning calorimetry (DSC) measurements.The spherical molecular brushes showed high molecular weights up to 230 kDa,and thus could be visualized by atomic force microscopy (AFM).AFM and dynamic laser light scattering (DLS) were employed to investigate the self-assembly properties of amphiphilic molecular brushes with closed proportion of hydrophobic and hydrophilic arms.The brushes could self-assemble hierarchically into spherical micelles,and network-like fibre structures,and again spherical micelles by addition of n-hexane into the dichloromethane or chloroform solution of brushes.In addition,this kind of miktoarms polymer brush also showed the ability of dye loading via host-guest encapsulation,which promises the potential application of spherical molecular brushes in supramolecular chemistry.

  2. Effect of the hydrophobic basal layer of thermoresponsive block co-polymer brushes on thermally-induced cell sheet harvest. (United States)

    Matsuzaka, Naoki; Takahashi, Hironobu; Nakayama, Masamichi; Kikuchi, Akihiko; Okano, Teruo


    Thermoresponsive poly(benzyl methacrylate)-b-poly(N-isopropylacrylamide) (PBzMA-b-PIPAAm) block co-polymer brush surfaces were prepared by surface-initiated two-step reversible addition-fragmentation chain transfer radical (RAFT) polymerization. PBzMA brushes were fabricated on azoinitiator-immobilized glass substrates in the presence of dithiobenzoate (DTB) compound as a RAFT agent. The amount of grafted polymer was regulated by initial monomer concentrations. The second thermoresponsive blocks were added to the RAFT-related DTB groups located at PBzMA termini through the propagation of PIPAAm chains, resulting in formation of PBzMA-b-PIPAAm brushes. Surface characteristics of the block co-polymer brushes and its influence on thermally regulated cellular behavior were investigated using bovine carotid artery endothelial cells (BAECs), compared with PIPAAm brush surfaces. Cell adhesion/detachment behavior on thermoresponsive polymer brush surfaces significantly depended on their individual polymer architectures and chemical compositions of grafted polymers. Low-temperature treatment at 20°C, below the phase-transition temperature of PIPAAm, induced the spontaneous detachment of adhering cells from the PBzMA-b-PIPAAm brush surfaces with a higher rate than that from PIPAAm brush surfaces. In addition, the cell-repellent effect of the hydrophobic basal layer successfully accelerated for harvesting BAEC sheets from the block co-polymer brush surfaces. Unique features of thermoresponsive block co-polymer brush architectures can be applied to control cell-adhesion strength for enhancing cell adhesion or accelerating cell detachment.

  3. Monitoring the Switching of Single BSA-ATTO 488 Molecules Covalently End-Attached to a pH-Responsive PAA Brush

    NARCIS (Netherlands)

    Akkilic, Namik; Molenaar, Robert; Claessens, Mireille M.A.E.; Blum, Christian; Vos, de Wiebe M.


    We describe a novel combination of a responsive polymer brush and a fluorescently labeled biomolecule, where the position of the biomolecule can be switched from inside to outside the brush and vice versa by a change in pH. For this, we grafted ultrathin, amino-terminated poly(acrylic acid) brushes

  4. Force-displacement measurements of earlywood bordered pits using a mesomechanical tester. (United States)

    Zelinka, Samuel L; Bourne, Keith J; Hermanson, John C; Glass, Samuel V; Costa, Adriana; Wiedenhoeft, Alex C


    The elastic properties of pit membranes are reported to have important implications in understanding air-seeding phenomena in gymnosperms, and pit aspiration plays a large role in wood technological applications such as wood drying and preservative treatment. Here we present force-displacement measurements for pit membranes of circular bordered pits, collected on a mesomechanical testing system. The system consists of a quartz microprobe attached to a microforce sensor that is positioned and advanced with a micromanipulator mounted on an inverted microscope. Membrane displacement is measured from digital image analysis. Unaspirated pits from earlywood of never-dried wood of Larix and Pinus and aspirated pits from earlywood of dried wood of Larix were tested to generate force-displacement curves up to the point of membrane failure. Two failure modes were observed: rupture or tearing of the pit membrane by the microprobe tip, and the stretching of the pit membrane until the torus was forced out of the pit chamber through the pit aperture without rupture, a condition we refer to as torus prolapse.

  5. Bordering Binarities and Cognitive Cartography: What on Earth Does Literature Have to do with Border Transactions?

    Directory of Open Access Journals (Sweden)

    Ruben Moi


    Full Text Available Although literature and poetry have numerous borders of their own,these are rarely assumed to have any significance for the world out-side the text itself. A number of reasons for this distinctive division certainly stem from the literary field itself. This paper intends to indicate the exclusivist stance of some theories of literature, and the inclucivist of others, before exploring the possibilities of bridging between borders in text and territory by reference to the life and literature of Oscar Wilde and a performative and imaginative analysis of Paul Muldoon's epigrammatic poem The Plot.

  6. Membrane Biophysics

    CERN Document Server

    Ashrafuzzaman, Mohammad


    Physics, mathematics and chemistry all play a vital role in understanding the true nature and functioning of biological membranes, key elements of living processes. Besides simple spectroscopic observations and electrical measurements of membranes we address in this book the phenomena of coexistence and independent existence of different membrane components using various theoretical approaches. This treatment will be helpful for readers who want to understand biological processes by applying both simple observations and fundamental scientific analysis. It provides a deep understanding of the causes and effects of processes inside membranes, and will thus eventually open new doors for high-level pharmaceutical approaches towards fighting membrane- and cell-related diseases.

  7. Effect of Antimicrobial Peptide-Amide: Indolicidin on Biological Membranes

    Directory of Open Access Journals (Sweden)

    Attila Gergely Végh


    Full Text Available Indolicidin, a cationic antimicrobial tridecapeptide amide, is rich in proline and tryptophan residues. Its biological activity is intensively studied, but the details how indolicidin interacts with membranes are not fully understood yet. We report here an in situ atomic force microscopic study describing the effect of indolicidin on an artificial supported planar bilayer membrane of dipalmitoyl phosphatidylcholine (DPPC and on purple membrane of Halobacterium salinarum. Concentration dependent interaction of the peptide and membranes was found in case of DPPC resulting the destruction of the membrane. Purple membrane was much more resistant against indolicidin, probably due to its high protein content. Indolicidin preferred the border of membrane disks, where the lipids are more accessible. These data suggest that the atomic force microscope is a powerful tool in the study of indolicidin-membrane interaction.

  8. Simulations of polymer brushes with charged end monomers under external electric fields (United States)

    Ding, Huanda; Duan, Chao; Tong, Chaohui


    Using Langevin dynamics simulations, the response of neutral polymer brushes with charged terminal monomers to external electric fields has been investigated. The external electric field is equivalent to the field generated by the opposite surface charges on two parallel electrodes. The effects of charge valence of terminal monomers on the structure of double layers and overall charge balance near the two electrodes were examined. Using the charge density distributions obtained from simulations, the total electric field normal to the electrodes was calculated by numerically solving the Poisson equation. Under external electric fields, the total electric field across the two electrodes is highly non-uniform and in certain regions within the brush, the total electric field nearly vanishes. The probability distribution of electric force acting on one charged terminal monomer was obtained from simulations and how it affects the probability density distribution of terminal monomers was analyzed. The response of polymer brushes with charged terminal monomers to a strongly stretching external electric field was compared with that of uniformly charged polymer brushes.

  9. Enhancement of charge-transport characteristics in polymeric films using polymer brushes

    DEFF Research Database (Denmark)

    Whiting, G.L.; Snaith, H.J.; Khodabakhsh, S.


    We show that charge-transporting polymer chains in the brush conformation can be synthesized from a variety of substrates of interest, displaying a high degree of stretching and showing up to a 3 orders of magnitude increase in current density normal to the substrate as compared with a spin-coated...

  10. Ultralow Friction with Hydrophilic Polymer Brushes in Water as Segregated from Silicone Matrix

    DEFF Research Database (Denmark)

    Røn, Troels; Javakhishvili, Irakli; Hvilsted, Søren


    , as the hydrophilic polymer brushes are generated from an internal source of the material, excellent grafting stability and restoring capabilities are revealed even under harsh tribostress. The film can easily be applied to elastomers, metals, and ceramic substrates by spin- or drip-coating. Obtained sliding fric...

  11. Synergy of brushing mode and antibacterial use on in vivo biofilm formation

    NARCIS (Netherlands)

    Jongsma, Marije A; Lagemaat, Marieke van de; Busscher, Henk J; Geertsema-Doornbusch, Geessien; Atema-Smit, Jelly; Mei, Henny C van der; Ren, Yijin


    OBJECTIVES: Orthodontic, multi-strand retention-wires are used as a generalized model for oral retention sites to investigate whether biofilm left-behind after powered toothbrushing in-vivo enabled better penetration of antibacterials as compared with manual brushing. METHODS: 2-cm multi-strand, sta

  12. Sand-wear resistance of brush electroplated nanocomposite coating in oil and its application to remanufacturing

    Institute of Scientific and Technical Information of China (English)

    DONG Shi-yun; XU Bin-shi; DU Ling-zhong; YANG Hua


    Sand-wear resistance of nano scale alumina particle reinforced nickel matrix composite coating (n-Al2O3/ Ni) prepared by brush electroplating technique was investigated via wear tests in sand-contaminated oil lubricant,comparing with that of AISI1045 steel and brush electroplated Ni coating. Effects of testing load, sand content and sand size on worn volume of the three materials, and also coating surface roughness on worn volume of the brush electroplated coatings were accessed. Results show that the worn volume of all the three materials increases with increasing of testing load, sand content and sand size. In the same conditions, n-Al2 O3/Ni composite coating has the smallest worn volume while AISI1045 steel has the largest because of the n-Al2 O3 particle effects. As to n-Al2 O3/Ni and Ni coatings, the surface-polished coatings have obviously lower worn volume than the as-plated coatings. The brush electroplated n-Als O3/Ni composite coating was employed to remanufacture the sand-worn bearing seats of a heavy vehicle and good results were gained.

  13. Improvement of hemocompatibility of polycaprolactone film surfaces with zwitterionic polymer brushes. (United States)

    Jiang, H; Wang, X B; Li, C Y; Li, J S; Xu, F J; Mao, C; Yang, W T; Shen, J


    Polycaprolactone (PCL) has been widely adopted as a scaffold biomaterial, but further improvement of the hemocompatibility of a PCL film surface is still needed for wide biomedical applications. In this work, the PCL film surface was functionalized with zwitterionic poly(3-dimethyl(methacryloyloxyethyl) ammonium propane sulfonate) (P(DMAPS)) brushes via surface-initiated atom transfer radical polymerization (ATRP) for enhancing hemocompatibility. Kinetics study revealed an approximately linear increase in graft yield of the functional P(DMAPS) brushes with polymerization time. The blood compatibilities of the modified PCL film surfaces were studied by platelet adhesion tests of platelet-rich plasma and human whole blood, hemolysis assay, and plasma recalcification time (PRT) assay. The improvement of hemocompatibility is dependent on the coverage of the grafted P(DMAPS) brushes on the PCL film. Lower or no platelet and blood cell adhesion was observed on the P(DMAPS)-grafted film surfaces. The P(DMAPS) grafting can further decrease hemolysis and enhance the PRT of the PCL surface. With the versatility of surface-initiated ATRP and the excellent hemocompatibility of zwitterionic polymer brushes, PCL films with desirable blood properties can be readily tailored to cater to various biomedical applications.

  14. Cosolvency-Induced Switching of the Adhesion between Poly(methyl methacrylate) Brushes

    NARCIS (Netherlands)

    Yu, Y.; Kieviet, B.D.; Kutnyanszky, E.; Vancso, G.J.; Beer, de S.


    We present a simple method to reversibly switch the adhesive force between two surfaces that are decorated with poly(methyl methacrylate) (PMMA) graft polymers. By employment of a PMMA/isopropanol/water or a PMMA/ethanol/water cosolvent system, we can tune the swelling of the brushes. In pure isopro

  15. Binary Mixed Homopolymer Brushes Tethered to Cellulose Nanocrystals: A Step Towards Compatibilized Polyester Blends. (United States)

    Mincheva, Rosica; Jasmani, Latifah; Josse, Thomas; Paint, Yoann; Raquez, Jena-Marie; Gerbaux, Pascal; Eyley, Samuel; Thielemans, Wim; Dubois, Philippe


    This article reports on the successful preparation and characterization of cellulose nanocrystals (CNCs) surface-modified with polylactide (PLA) and poly(butylene succinate) (PBS) binary mixed homopolymer brushes. Their synthesis was designed as a three-step procedure combining polyester synthesis and surface-modification of CNCs with simultaneous polyester grafting via a heterogeneous copper(I)-catalyzed azide-alkyne cycloaddition reaction. For comparison, single homopolymer brushes tethered to CNCs (PLLA-g-CNC and PBSBDEMPAM-g-CNC) were obtained applying the same procedure. The hairy nanoparticles were characterized in terms of chemical composition and thermal properties. Spectroscopic analyses suggested "rippled" microphase separation of both immiscible homopolyesters in the mixed brushes, while others showed impeded homopolyester crystallization after surface-grafting. A synergistic relationship between the polyesters and CNCs was also suggested, i.e., the polyester grafting increases the CNC thermal resistance, while CNC presence imparts char formation. The as-obtained binary homopolymer brushes tethered to nanoparticles makes these surface-modified cellulosic nanomaterials attractive as compatibilization/reinforcement agents for PLA/PBS blends.

  16. Brush seal leakage performance with gaseous working fluids at static and low rotor speed conditions (United States)

    Carlile, Julie A.; Hendricks, Robert C.; Yoder, Dennis A.


    The leakage performance of a brush seal with gaseous working fluids at static and low rotor speed conditions was studied. The leakage results included for air, helium, and carbon dioxide at several bristle/rotor interferences. Also, the effects of packing a lubricant into the bristles and also of reversing the pressure drop across the seal were studied. Results were compared to that of an annular seal at similar operating conditions. In order to generalize the results, they were correlated using corresponding state theory. The brush seal tested had a bore diameter of 3.792 cm (1.4930 in.), a fence height of 0.0635 cm (0.025 in.), and 1800 bristles/cm circumference (4500 bristles/in. circumference). Various bristle/rotor radial interferences were achieved by using a tapered rotor. The brush seal reduced the leakage in comparison to the annular seal, up to 9.5 times. Reversing the pressure drop across the brush seal produced leakage rates approximately the same as that of the annular seal. Addition of a lubricant reduced the leakage by 2.5 times. The air and carbon dioxide data were successfully correlated using corresponding state theory. However, the helium data followed a different curve than the air and carbon dioxide data.

  17. Abrasion of human enamel by brushing with a commercial dentifrice containing hydroxyapatite crystals in vitro. (United States)

    Kodaka, T; Kobori, M; Hirayama, A; Abe, M


    Automatic toothbrushing with a commercial dentifrice containing hydroxyapatite (HAP) crystals was performed on the tangential polished surfaces of sound human enamel, mainly consisting of biological apatite similar to HAP, for 10 min in vitro. The X-ray diffraction peaks of HAP, brushite (DCPD), and monetite (DCP) crystals were detected from the dentifrice. After brushing, the enamel surfaces were observed with a scanning electron and a confocal scanning laser microscope. The brushing caused larger abrasive loss and more remarkable roughness of the enamel surfaces following the broad traces of brush bristles and the exposure of prism structures than brushing with a dentifrice containing only DCPD, which we previously reported. We claim that the fine granular-shaped HAP crystals of the dentifrice indicated as an active ingredient for preventing enamel caries possess stronger abrasivity of sound enamel than the DCPD and DCP as abrasives on account of their Mohs hardness values rather than sizes and shapes. The HAP crystals of dentifrices may not occlude the small defects of early caries enamel, but erode them more strongly as an abrasive than the other abrasives.

  18. Synergy of brushing mode and antibacterial use on in vivo biofilm formation

    NARCIS (Netherlands)

    Jongsma, Marije A.; de Lagemaat, Marieke van; Busscher, Henk J.; Geertsema-Doornbusch, Gesinda I.; Atema-Smit, Jelly; , van der Mei, Henny C.; Ren, Yijin


    Objectives: Orthodontic, multi-strand retention-wires are used as a generalized model for oral retention sites to investigate whether biofilm left-behind after powered toothbrushing in-vivo enabled better penetration of antibacterials as compared with manual brushing. Methods: 2-cm multi-strand, sta

  19. Comprehensive theory for star-like polymer micelles: combining classical nucleation and polymer brush theory

    NARCIS (Netherlands)

    Sprakel, J.H.B.; Leermakers, F.A.M.; Cohen Stuart, M.A.; Besseling, N.A.M.


    A comprehensive theory is proposed that combines classical nucleation and polymer brush theory to describe star-like polymer micelles. With a minimum of adjustable parameters, the model predicts properties such as critical micelle concentrations and micellar size distributions. The validity of the p

  20. Urine versus brushed samples in human papillomavirus screening: study in both genders.

    NARCIS (Netherlands)

    Hauwers, K.W.M. d'; Depuydt, C.; Bogers, J.P.; Stalpaert, M.; Vereecken, A.; Wyndaele, J.J.; Tjalma, W.


    AIM: To investigate whether urine is a good medium for screening and whether there is a correlation between the amount of extracted DNA and human papillomavirus (HPV)-positivity. METHODS: In the present study, 30 first-voided urine (FVU) specimens and 20 urethroglandular swabs using cervex-brushes f

  1. Mate choice in Australian brush-turkeys Alectura lathami : a preliminary report

    NARCIS (Netherlands)

    Birks, S.


    Female brush-turkeys respond to several factors when choosing with whom they will mate and where they will lay their eggs. The most important factors seem to be mound condition (especially incubation stage and digging effort required), male presence at mounds (though not necessarily male quality), a

  2. Stable Protein-Repellent Zwitterionic Polymer Brushes Grafted from Silicon Nitride

    NARCIS (Netherlands)

    Nguyen, Ai T.; Baggerman, Jacob; Paulusse, Jos M.J.; Rijn, van Cees J.M.; Zuilhof, Han


    Zwitterionic poly(sulfobetaine acrylamide) (SBMAA) brushes were grafted from silicon-rich silicon nitride (SixN4, x > 3) surfaces by atom transfer radical polymerization (ATRP) and studied in protein adsorption experiments. To this aim ATRP initiators were immobilized onto SixN4 through stable Si−C

  3. Clinical evaluation of an ionic tooth brush on oral hygiene status, gingival status, and microbial parameter

    Directory of Open Access Journals (Sweden)

    Deshmukh J


    Full Text Available It has long been recognised that the presence of dental plaque leads to gingivitis and periodontal disease, as well as dental caries. Today tooth brushing is the most widely accepted method of removing plaque. Hence this present clinical study was undertaken to evaluate the effectiveness of an ionic toothbrush on oral hygiene status. For this study, 20 dental students in the age group of 18-20 years were included. All the subjects after undergoing dental prophylaxis were then provided with ionic toothbrushes, either active (equipped with lithium battery or inactive (without lithium battery. Plaque index and gingival bleeding index were examined at 7th, 14th, and 21st day. Microbial assessment was done for detection of colony forming units (CFU from the plaque samples which were collected on 0 day and 21st day, both before brushing and after brushing. Results shown a significant reduction in all the parameters and the reduction was more significant in active and inactive ionic toothbrush users. It was concluded that both active and inactive ionic toothbrushes reduced the plaque index and gingival bleeding index scores significantly and active ionic tooth brushes were more effective as compared to inactive ionic toothbrushes. There was no soft tissue trauma following the use of both type of toothbrushes, which showed that ionic toothbrushes were equally safe for regular long-term use.

  4. Microbial adhesion to poly(ethylene oxide) brushes: Influence of polymer chain length and temperature

    NARCIS (Netherlands)

    Roosjen, A.; Mei, van der H.C.; Busscher, H.J.; Norde, W.


    Glass surfaces were modified by end-grafting poly(ethylene oxide) (PEO) chains having molecular weights of 526, 2000, or 9800 Da. Characterization using water contact angles, ellipsometry, and X-ray photoelectron spectroscopy confirmed the presence of the PEO brushes on the surface with estimated le

  5. Microbial adhesion to poly(ethylene oxide) brushes : Influence of polymer chain length and temperature

    NARCIS (Netherlands)

    Roosjen, A; van der Mei, HC; Busscher, HJ; Norde, W


    Glass surfaces were modified by end-grafting poly(ethylene oxide) (PEO) chains having molecular weights of 526,2000, or 9800 Da. Characterization using water contact angles, ellipsometry, and X-ray photoelectron spectroscopy confirmed the presence of the PEO brushes on the surface with estimated len

  6. A facile avenue to conductive polymer brushes via cyclopentadiene-maleimide Diels-Alder ligation. (United States)

    Yameen, Basit; Rodriguez-Emmenegger, Cesar; Preuss, Corinna M; Pop-Georgievski, Ognen; Verveniotis, Elisseos; Trouillet, Vanessa; Rezek, Bohuslav; Barner-Kowollik, Christopher


    Cyclopentadienyl end-capped poly(3-hexylthiophene) was employed to fabricate conductive surface tethered polymer brushes via a facile route based on cyclopentadiene-maleimide Diels-Alder ligation. The efficient nature of the Diels-Alder ligation was further combined with a biomimetic polydopamine-assisted functionalization of surfaces, making it an access route of choice for P3HT surface immobilization.

  7. The efficacy of interdental brushes on plaque and parameters of periodontal inflammation: a systematic review

    NARCIS (Netherlands)

    D.E. Slot; C.E. Dörfer; G.A. van der Weijden


    Aim: The aim of the study was to asses the effect of the use of interdental brushes (IDB) in patients as an adjunct to toothbrushing compared with toothbrushing alone or other interdental oral hygiene devices on plaque and the clinical parameters of periodontal inflammation. Material and methods: ME

  8. Effect of a chlorhexidine-containing brush-on gel on peri-implant mucositis

    DEFF Research Database (Denmark)

    Hallström, H; Lindgren, S; Twetman, S


    OBJECTIVE: The aim was to evaluate the effect of a chlorhexidine-containing brush-on gel when used as supplement to oral hygiene instructions and mechanical debridement, on peri-implant mucositis in adults. MATERIALS AND METHODS: The study group consisted of 38 adults (48-87 years.) with peri-implant...... of peri-implant mucositis....

  9. Boundary lubrication by brushed salivary conditioning films and their degree of glycosylation

    NARCIS (Netherlands)

    Veeregowda, Deepak H; van der Mei, Henderina; de Vries, Jacob; Rutland, Mark W; Valle-Delgado, Juan J; Sharma, Prashant K; Busscher, Hendrik


    Toothbrushing, though aimed at biofilm removal, also affects the lubricative function of adsorbed salivary conditioning films (SCFs). Different modes of brushing (manual, powered, rotary-oscillatory or sonically driven) influence the SCF in different ways. Our objectives were to compare boundary lub

  10. Stable Protein-Repellent Zwitterionic Polymer Brushes Grafted from Silicon Nitride

    NARCIS (Netherlands)

    Nguyen, A.T.; Baggerman, J.; Paulusse, J.M.J.; Rijn, van C.J.M.; Zuilhof, H.


    Zwitterionic poly(sulfobetaine acrylamide) (SBMAA) brushes were grafted from silicon-rich silicon nitride (SixN4, x > 3) surfaces by atom transfer radical polymerization (ATRP) and studied in protein adsorption experiments. To this aim ATRP initiators were immobilized onto SixN4 through stable Si

  11. A modified box model including charge regulation for protein adsorption in a spherical polyelectrolyte brush

    NARCIS (Netherlands)

    Biesheuvel, P.M.; Wittemann, A.


    Recent experiments showed significant adsorption of bovine serum albumin (BSA) in spherical polyelectrolyte brushes (SPB) consisting of polyacrylic acid, even for pH values above the isoelectric point of the protein, when both protein and polyion are negatively charged. To describe these experimenta

  12. The efficacy of powered toothbrushes following a brushing exercise: a systematic review

    NARCIS (Netherlands)

    Rosema, N.A.M.; Slot, D.E.; van Palenstein Helderman, W.H.; Wiggelinkhuizen, L.; Van der Weijden, G.A.


    Aim: The primary objective was to determine, based on the available published evidence, the efficacy of powered toothbrushing following a brushing exercise and secondary to what magnitude this effect is dependent on the plaque index score, power supply and mode of action. Material and Methods: The P

  13. Plaque-left-behind after brushing : intra-oral reservoir for antibacterial toothpaste ingredients

    NARCIS (Netherlands)

    Otten, Marieke P. T.; Busscher, Henk J.; Abbas, Frank; van der Mei, Henny C.; van Hoogmoed, Chris G.


    Plaque is never fully removed by brushing and may act as a reservoir for antibacterial ingredients, contributing to their substantive action. This study investigates the contribution of plaque-left-behind and saliva towards substantivity of three antibacterial toothpastes versus a control paste with

  14. Effects of Chairside Polishing and Brushing on Surface Roughness of Acrylic Denture Base Resins

    Institute of Scientific and Technical Information of China (English)

    Seung-Kyun Kim; Ju-Mi Park; Min-Ho Lee; Jae-Youn Jung; Shipu Li; Xinyu Wang


    The effects of 3 chairside polishing kits and mechanical brushing on the surface roughness of 3 different acrylic denture base resins were compared. Acrylic denture base resins (auto-polymerizing, heat-polymerizing, injected heat-polymerizing resins) were examined after a tungsten carbide bur, and after chairside polishing using 3 polishing kits and pumice. The specimens were subjected to mechanical brushing using a wear tester to simulate 30 000 strokes of brushing. The surface roughness of the acrylic denture base resin specimens was measured using a contact pro-filometer. After the test, the random polished acrylic resins were evaluated by scanning electron mi-croscopy (SEM) and atomic force microscopy (AFM). Acrylic denture base resins polished using the 3 types of polishing kits had a smoother surface than those finished with the tungsten carbide bur (p <0.05). The surface of the resin polished by a TC cutter exceeded the Ra of 0.2 μm (p<0.05). The auto-polymerizing resin showed a significantly higher surface roughness than the heat-polymerizing resin and injected heat-polymerizing resin (p>0.05). In the case of polishing step wise, there was almost no change in surface roughness after brushing (p>0.05).

  15. High density hydrophilic and hydrophobic brush coatings using a polymeric primer layer

    NARCIS (Netherlands)

    Cate, A.T. ten; Reinders, S.A.F.; Turkenburg, D.H.; Bruin, A.; D'Souza, F.; Donnelly, G.T.; Willemsen, P.R.; Maas, J.H.; Bommel, K.J.C. van


    Polymer brush coatings, consisting of polymer chains covalently attached to a surface and being less than a hundred nanometer thick, allow the creation of functional surfaces without altering the inherent bulk properties or appearance of a product. Surface properties depend on the type and length of

  16. Organic thin film transistors with polymer brush gate dielectrics synthesized by atom transfer radical polymerization

    DEFF Research Database (Denmark)

    Pinto, J.C.; Whiting, G.L.; Khodabakhsh, S.


    Low operating voltage is an important requirement that must be met for industrial adoption of organic field-effect transistors (OFETs). We report here solution fabricated polymer brush gate insulators with good uniformity, low surface roughness and high capacitance. These ultra thin polymer films...

  17. Energy transfer, volumetric expansion, and removal of oral biofilms by non-contact brushing

    NARCIS (Netherlands)

    Busscher, H. J.; Jager, D.; Finger, G.; Schaefer, N.; van der Mei, H. C.


    Non-contact removal of oral biofilms offers advantages beyond the reach of bristles, but it is unknown how energy transfer for removal from brush-to-biofilm occurs. In the present study we evaluated non-contact, oral biofilm removal by oscillating-rotating and sonic toothbrushes, and their acoustic

  18. The new borders of Saint Louis

    Directory of Open Access Journals (Sweden)

    Fabrice Delsahut


    Full Text Available In 1904 the Olympic and Anthropologic Games in Saint Louis, Missouri, were lost in the chaos of the Louisiana Purchase (Universal Exposition. Although the expected universal spirit, for a long time Saint Louis expressed racial prejudices of its personal. This paper shows up how Sport Sciences and growing up Anthropology acted together in sense of serving questioned causes like racial ranking and colonization right. They were important in improving a feeling of nation in North American that took in grant sport as part of its constitution. The Universal Exposition and Market of Saint Louis offered new possibilities in definition of technological, racial, geographic and corporal borders.

  19. Early seismicity of the Scottish Borders Region

    Directory of Open Access Journals (Sweden)

    R. M. W. Musson


    Full Text Available This paper considers the seismicity of Southern Scotland and Northern England up to the year 1750. This area was formerly a border area between two states that eventually became politically united. Much of the area is uplands, and the seismicity is moderate to low. This makes for some problems in studying historical seismicity, yet the area provides a number of case studies of general interest in the field of historical seismology, including a rare case of being able to track down a «missing» earthquake.

  20. Application of IR microbolometers in border surveillance (United States)

    Breakfield, David K.; Norton, Peter; Plemons, Dan; Rodriguez, Christian; Sustare, Dennis


    BAE Systems led a collaborative study with New Mexico State University to investigate a series of ground based persistent surveillance solutions for potential use along the Southwest border of the United States. This study considered a wide range of system options for mobile and fixed site applications. This paper summarizes the findings of the study including the central role of the imaging subsystems in mobile ground based surveillance solutions and the suitability of uncooled IR Microbolometers within this subsystem. The paper also provides a discussion of the benefits of real time decision support applications when fielding a persistent surveillance solution.

  1. Comparative balance of border regulations in four neighboring Caribbean countries

    Directory of Open Access Journals (Sweden)

    Silvia Cristina Mantilla Valbuena


    Full Text Available This article seeks to investigate whether there is a potential for border integration among four adjoining Caribbean countries: Colombia, Nicaragua, Panama and Costa Rica. The discussion is part of the “cross-border” concept and the integration of subnational entities in two or more nation states, with particular emphasis on the role played by the societies that inhabit border regions. A comparative analysis model is used to assess border regulations in each country’s various territorial levels based on relevant legal elements, autonomous processes and decentralization. The article concludes that the more modern each country’s border regulations and constitutional, political and administrative reforms are, the greater the likelihood of cross-border integration. Colombia and Nicaragua have the highest potential for integrating their borders, whereas Panama and Costa Rica have the lowest potential.

  2. Cross-border shopping and tourism destination marketing

    DEFF Research Database (Denmark)

    Makkonen, Teemu


    This article addresses the economic impact that cross-border shopping has on the local tourism industry and the ways that cross-border shopping is taken advantage of in tourism destination marketing. Southern Jutland–situated in Denmark just north of the German border, where border shops situated...... a tourist attraction in itself, which benefits the local economies on both sides of the border. However, this potential is not taken advantage of in tourism destination marketing. The article, thus, concludes with suggestions for the tourism industry to develop its image and brand by integrating cross...... just south of the same border enable Danes to capitalize on the lower value added tax levels in Germany–is utilized as an illustrative case example. The data was collected by analysing the relevant tourism destination marketing material and via interviews with local destination marketing organizations...

  3. Managing US-Mexico "border health": an organizational field approach. (United States)

    Collins-Dogrul, Julie


    During World War II Mexican and US health professionals and organizations constructed a transnational organizational field to manage the border's public health problems. Despite barriers to inter-organizational cooperation, including disparate administrative structures and North-South stratification, the field's transnational approach to health on the border has continued for 60 years. Using archival data to track changes in the number and types of organizations, this article argues that the field practitioners call "border health" reconfigured during the North American Free Trade Association (NAFTA) decade from an era of loosely organized professionals to a specialized bureaucracies era. This change brought new vitality to border health, with transnational ties increasing and diversifying, but has not weakened entrenched cross-border inequalities. The organizational history of the US-Mexico border health field demonstrates how macro-politics and inter-organizational stratification shape transnational public health problems.

  4. Temporary reintroduction of border controls at French borders inside the Schengen Area

    CERN Multimedia


    The French authorities have informed CERN that, in view of the upcoming COP21 Paris Climate Conference, France will exceptionally reintroduce controls at its borders with Schengen states for one month from 13 November to 13 December 2015. All border posts and crossing points between France and Switzerland will be affected by this measure.   Members of the personnel are therefore reminded that, when crossing borders within the Schengen Area*, they must carry: either, in the case of citizens of European Economic Area (EEA) countries and Switzerland, an official identity document (identity card or passport); or, in the case of non-EEA and non-Swiss citizens, an identity document together with a Schengen visa if they are subject to this obligation, or an identity document together with a residence permit issued by a Schengen state** if they have one.   The French authorities will make every effort to limit the impact of this measure on cross-border traffic, and wish to thank the members of th...

  5. Electricity without borders - The need for cross-border transmission investment in Europe

    NARCIS (Netherlands)

    Brancucci Martínez-Anido, C.


    An increase in cross-border electricity flows is foreseen in Europe in the coming decades due to large-scale penetration of renewable energy, the electrical integration of the Euro-Mediterranean region, the electrification of transport, and possible shifts in electricity generation dispatc

  6. Border Cracks: Approaching Border Security From a Complexity Theory and Systems Perspective (United States)


    33 o. Secretaria de Seguridad Publica (SSP) ..................................34 viii p. Federal Police (PF...SIU Sensitive Information Unit SOD Special Operations Division SSP Secretaria de Seguridad Publica SWB Southwest Border Initiative 34 o. Secretaria de Seguridad Publica (SSP) SSP is part of the Federal Civil Service whose aim is

  7. Lung malignancy: Diagnostic accuracies of bronchoalveolar lavage, bronchial brushing, and fine needle aspiration cytology

    Directory of Open Access Journals (Sweden)

    Rateesh Sareen


    Full Text Available Background: Early diagnosis of lung cancer plays a pivotal role in reducing lung cancer death rate. Cytological techniques are safer, economical and provide quick results. Bronchoscopic washing, brushing and fine needle aspirations not only complement tissue biopsies in the diagnosis of lung cancer but also comparable. Objectives: (1 To find out diagnostic yields of bronchioalveolar lavage , bronchial brushings, FNAC in diagnosis of lung malignancy. (2 To compare relative accuracy of these three cytological techniques. (3 To correlate the cytologic diagnosis with clinical, bronchoscopic and CT findings. (4 Cytological and histopathological correlation of lung lesions. Methods: All the patients who came with clinical or radiological suspicion of lung malignancy in two and a half year period were included in study. Bronchoalveolar lavage was the most common type of cytological specimen (82.36%, followed by CT guided FNAC (9.45% and bronchial brushings (8.19%. Sensitivity, specificity, positive and negative predictive value for all techniques and correlation with histopathology was done using standard formulas. Results: The most sensitive technique was CT FNAC – (87.25% followed by brushings (77.78% and BAL (72.69%. CT FNAC had highest diagnostic yield (90.38%, followed by brushings (86.67% and BAL (83.67%. Specificity and positive predictive value were 100 % each of all techniques. Lowest false negatives were obtained in CT FNAC (12.5% and highest in BAL (27.3%. Highest negative predictive value was of BAL 76.95 % followed by BB 75.59% and CT FNAC 70.59%. Conclusion: Before administering antitubercular treatment every effort should be made to rule out malignancy. CT FNAC had highest diagnostic yield among three cytological techniques. BAL is an important tool in screening central as well as in accessible lesions. It can be used at places where CT guided FNAC is not available or could not be done due to technical or financial limitations

  8. Electric double layer electrostatics of pH-responsive spherical polyelectrolyte brushes in the decoupled regime. (United States)

    Li, Hao; Chen, Guang; Das, Siddhartha


    Understanding the behavior and properties of spherical polyelectrolyte brushes (SPEBs), which are polyelectrolyte brushes grafted to a spherical core, is fundamental to many applications in biomedical, chemical and petroleum engineering as well as in pharmaceutics. In this paper, we study the pH-responsive electrostatics of such SPEBs in the decoupled regime. In the first part of the paper, we derive the scaling conditions in terms of the grafting density of the PEs on the spherical core that ensure that the analysis can be performed in the decoupled regime. In such a regime the elastic and the excluded volume effects of polyelectrolyte brushes (PEBs) can be decoupled from the electrostatic effects associated with the PE charge and the induced EDL. As a consequence the PE brush height, assumed to be dictated by the balance of the elastic and excluded volume effects, can be independent of the electrostatic effects. In the second part, we quantify the pH-responsive electrostatics of the SPEBs - we pinpoint that the radial monomer distribution for a given brush molecule exhibit a non-unique cubic distribution that decays away from the spherical core. Such a monomer distribution ensures that the hydrogen ion concentration is appropriately accounted for in the description of the SPEB thermodynamics. We anticipate that the present analysis, which provides possibly one of the first models for probing the electrostatics of pH-responsive SPEBs in a thermodynamically-consistent framework, will be vital for understanding the behavior of a large number of entities ranging from PE-coated NPs and stealth liposomes to biomolecules like bacteria and viruses.

  9. Evaluation of a brushing machine for estimating density of spider mites on grape leaves. (United States)

    Macmillan, Craig D; Costello, Michael J


    Direct visual inspection and enumeration for estimating field population density of economically important arthropods, such as spider mites, provide more information than alternative methods, such as binomial sampling, but is laborious and time consuming. A brushing machine can reduce sampling time and perhaps improve accuracy. Although brushing technology has been investigated and recommended as a useful tool for researchers and integrated pest management practitioners, little work to demonstrate the validity of this technique has been performed since the 1950's. We investigated the brushing machine manufactured by Leedom Enterprises (Mi-Wuk Village, CA, USA) for studies on spider mites. We evaluated (1) the mite recovery efficiency relative to the number of passes of a leaf through the brushes, (2) mite counts as generated by the machine compared to visual counts under a microscope, (3) the lateral distribution of mites on the collection plate and (4) the accuracy and precision of a 10% sub-sample using a double-transect counting grid. We found that about 95% of mites on a leaf were recovered after five passes, and 99% after nine passes, and mite counts from brushing were consistently higher than those from visual inspection. Lateral distribution of mites was not uniform, being highest in concentration at the center and lowest at the periphery. The 10% double-transect pattern did not result in a significant correlation with the total plate count at low mite density, but accuracy and precision improved at medium and high density. We suggest that a more accurate and precise sample may be achieved using a modified pattern which concentrates on the center plus some of the adjacent area.

  10. Increased photocatalytic activity of tube-brush-like ZnO nanostructures fabricated by using PVP nanofibers as templates

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xinying; Zhai, Yingjiao [School of Science, International Joint Research Center for Nanophotonics and Biophotonics, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022 (China); Li, Jinhua, E-mail: [School of Science, International Joint Research Center for Nanophotonics and Biophotonics, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022 (China); Fang, Xuan [School of Science, International Joint Research Center for Nanophotonics and Biophotonics, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022 (China); State Key Laboratory of High Power Semiconductor Laser, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022 (China); Fang, Fang; Chu, Xueying [School of Science, International Joint Research Center for Nanophotonics and Biophotonics, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022 (China); Wei, Zhipeng; Wang, Xiaohua [State Key Laboratory of High Power Semiconductor Laser, Changchun University of Science and Technology, 7089 Wei-Xing Road, Changchun 130022 (China)


    Highlights: • We obtained the tube-brush-like ZnO nanostructures. • We used polyvinylpyrrolidone (PVP) nanofibers used as templates by ALD and hydrothermal method to prepare tube-brush-like ZnO nanostructure. • The tube-brush-like ZnO nanostructures showed higher photocatalytic activity, the degradation of Rhodamine B (RhB) was up to 98% after 2 h of irradiation. - Abstract: The tube-brush-like ZnO nanostructures were synthesized by hydrothermal method using electrospinning polyvinylpyrrolidone (PVP) nanofibers as templates. The photocatalytic activity of as-grown samples was investigated by photo-degradation of Rhodamine B (RhB). The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV/visible absorption spectroscopy (UV–vis) and photoluminescence (PL) spectroscopy. It was found that the morphologies of the prepared ZnO were tube-brush-like nanostructures. With the grown time increasing, the crystal and the optical properties were improved. In the photocatalytic experiment, the tube-brush-like ZnO nanostructures photocatalytic activity was enhanced the degradation of RhB was up to 98% after 2 h of irradiation. The tube-brush-like ZnO nanostructures showed higher photocatalytic activity because of the special surface morphology.

  11. Development of plastic elongation in nanocrystalline and amorphous Ni–W dual phase alloys by brushing technique

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, S., E-mail:; Adachi, H., E-mail:; Yamasaki, T., E-mail:


    Highlights: • A novel agitation technique called the brushing technique is proposed. • A homogeneous material can be obtained with the brushing technique. • The brushed material exhibits large plastic elongation with work hardening. - Abstract: A novel agitation technique, referred to as the “brushing technique” is proposed to treat the surface of a Ni–W alloy film during electrodeposition. This technique was developed to directly remove hydrogen bubbles on the film surface and to apply Ni ions to the interfacial layer with the substrate. The intrinsic mechanical properties of the Ni–W electrodeposits are then evaluated with respect to application. High resolution transmission electron microscopy observations revealed that both treated and untreated films have nanocrystallites of approximately 5 nm in diameter and an amorphous phase. There was a compositional difference of about. 1.4 at% W between the face side and the reverse side of the film that was not subjected to the brushing technique, whereas this difference was absent in the film subjected to the brushing technique. In addition, the brushing technique reduced the surface roughness of the film and decreased the number of defects. As a result, a large plastic strain of about. 2.9% was observed with work hardening under tensile testing.

  12. Photo-induced in situ crosslinking of polymer brushes with dimethyl maleimide moieties for dynamically stimulating stem cell differentiation. (United States)

    Arisaka, Yoshinori; Nishijima, Yuka; Yusa, Shin-Ichi; Takeda, Naoya


    We designed photo-crosslinkable polymer brushes with dimethylmaleimide moieties, in order to demonstrate dynamic stimulation of cell differentiation in mesenchymal stem cells (MSCs). The polymer brushes were synthesized by surface-initiated reversible addition fragmentation chain transfer polymerization using dimethylmaleimide ethyl methacrylate and methyl methacrylate on a chain transfer agent-immobilized glass surface. The polymer brushes were crosslinked by photodimerization of the dimethylmaleimide moieties within polymer chains with stem cells present on the surface. In order to evaluate the effects of in situ photo-induced crosslinking of the polymer brushes on gene expression of stem cells, human bone marrow MSCs were cultured under static and dynamic culture conditions for 7 days. Expression of the osteocalcin (Ocn) gene in MSCs was used as an indicator of osteoblast differentiation under dynamic culture conditions. Structural conversion from non-crosslinked polymer brushes to crosslinked polymer brushes increased the expression of Ocn by 1.4-fold in the presence of adhered cells, compared with non-crosslinked polymer brushes under static culture conditions. These results suggest that MSCs recognized surface conversion from non-crosslinked to crosslinked structures, which resulted in altered differentiation lineages. Therefore, photo-crosslinkable surfaces with dimethyl maleimide moieties are potential novel materials for dynamically stimulating MSC differentiation.

  13. Fluid and air-stable lipopolymer membranes for biosensor applications. (United States)

    Albertorio, Fernando; Diaz, Arnaldo J; Yang, Tinglu; Chapa, Vanessa A; Kataoka, Sho; Castellana, Edward T; Cremer, Paul S


    The behavior of poly(ethylene glycol) (PEG) conjugated lipids was investigated in planar supported egg phosphatidylcholine bilayers as a function of lipopolymer density, chain length of the PEG moiety, and type of alkyl chains on the PEG lipid. Fluorescence recovery after photobleaching measurements verified that dye-labeled lipids in the membrane as well as the lipopolymer itself maintained a substantial degree of fluidity under most conditions that were investigated. PEG densities exceeding the onset of the mushroom-to-brush phase transition were found to confer air stability to the supported membrane. On the other hand, substantial damage or complete delamination of the lipid bilayer was observed at lower polymer densities. The presence of PEG in the membrane did not substantially hinder the binding of streptavidin to biotinylated lipids present in the bilayer. Furthermore, above the onset of the transition into the brush phase, the protein binding properties of these membranes were found to be very resilient upon removal of the system from water, rigorous drying, and rehydration. These results indicate that supported phospholipid bilayers containing lipopolymers show promise as rugged sensor platforms for ligand-receptor binding.

  14. First Philosophy in the Border Zone

    Directory of Open Access Journals (Sweden)

    Viggo Rossvaer


    Full Text Available The article will be devoted to such problems as a idea of subsidiarity, a cosmopolitan right and a visitor figure in context and interpretation of ancient and modern philosophy. The article deals with the concept of subsidiarity which is taken as a point of departure for the discipline of borderology, an academic study with Kantian roots. Borderology, according to the principle of subsidiarity, can present as a new field of investigation which invites philosophers and social scientists to replace a “top down” with a “bottom up” procedure. The figure of the visitor is close linked with the experience of subsidiarity which means the freedom and initiative below the level of State. In Immanuel Kant’s strategy for perpetual peace, the figure of the visitor launches a critique of a tendency to self-aggrandizement, characteristic of the modern State and thereby a defense of the political independence of local border regions. The visitor also invites us to see, think and work to liberate our own subjectivity from false voices of sovereignty. Kant articulates the offer of the visitor by bringing in the term Verkehr. Using Kant scholar Otfried Höffe,s methodology we show how idea of subsidiarity is overlooked in international political theory, explain some constitutive principles of borderology, from which is more important is the methodological principle of an intercultural discourse and presents borderology as an anti-Huntingtonian model for border studies.

  15. Seismicity at Jalisco-Nayarit Border, Mexico (United States)

    Rutz, M.; Nunez-Cornu, F.; Camarena, M.; Trejo, E.; Reyes-Davila, G.; Suarez-Plasencia, C.


    Since 2002 a regional seismic network from Jalisco Civil Defense and University of Guadalalajara is monitoring seismicity at the northwest border of Jalisco block. With the installation of a seismic station on Ceboruco Volcano, by Nayarit Civil Defense, coverage of the network extends to east. Ceboruco Volcano is located on the Tepic-Zacoalco graben, the east border of Jalisco block, this allow us to begin to monitoring this area. The zone of Bahia de Banderas, between the north coast of Jalisco and south coast of Nayarit, probably on a tectonic triple point, is a region of high seismic potential. Activ tectonic structures and clusters in the zone of El Tuito and the Dam Cajon de Pe¤as have been identified. The seismicity in the north area of the bay is low, meanwhile in the south, where the bay is deeper, the seismicity level is higher with an East-West tendency. At the east, the Amatlan de Ca¤as-Ameca zone presents continue activity, here have been possible to locate events with local magnitude between 2 and 4. Tectonovolcanic events registred at Ceboruco station presents waveform with scattering. The seismic distribution of the coast of Jalisco shows parallel alignments to the trench throughout al the coast. Other perpendicular alignments to the coastline show active morphologic structures within the Jalisco block related to the subduction of the Rivera plate under the Jalisco block.

  16. Multi-TSO cross border balancing mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Llorens, Maria Luisa; Moreno, Laura; Fuente, Jose Ignacio de la; Junco, Paula; Arenillas, Jorge [Red Electrica de Espana (REE) S.A.U., Madrid (Spain). Operation Markets Dept.; Pereira, Pedro [REN - Servicos, S.A., Lisbon (Portugal). Gabinete Mercado e Liquidacoes; Chabanne, Colas [RTE Reseau de Transport d' Electricite, Paris (France). Markets Dept.; Apoyan, Lalake; Barbieri, Galileo [RTE Reseau de Transport d' Electricite, Paris (France). Cross-Border Market Design


    The balancing market integration has been highlighted as a necessary step to reach the European Union goal for the development of an effective, competitive single market for electricity across Europe. In this paper it is described the work done by RTE, REE and REN regarding the design of a non-discriminatory, efficient and reliable multi-TSO Cross Border Balancing Mechanism at regional level, extendible to other control areas. The implementation of this multi-TSO Cross Border Balancing Mechanism will aim at increasing the operational security, enhancing the Liquidity and Competition of balancing markets, facilitating the integration of energy produced by Renewable Energy Sources while optimizing the use of Interconnection capacities. With this mechanism, the three TSOs will be able to exchange to each other balancing energy through the available interconnection capacities after the last intraday market sessions. This mechanism will be based on a common IT platform where TSOs will share their available surplus of reserves and communicate their balancing needs. The available interconnection capacities will be taken into account in an automatic and centralized way. Two main options are investigated regarding the allocation method: on the one hand, the first come first served approach (FCFS), on the other hand, the ''social welfare'' optimization approach. (orig.)

  17. "Crossing Borders" ja valmimislootuses Eesti Muusika- ja Teatriakadeemia / Malle Maltis

    Index Scriptorium Estoniae

    Maltis, Malle, 1977-


    19. - 29. augustini EMTAs toimunud rahvusvahelisest suvekursusest "Crossing Borders in Interpretation of Classical Music and Jazz". Kooli välissuhete prorektor sellest projektist ja muusikaakadeemia juurdeehitusest

  18. The Assessment Of Geographical Borders In Economic Research

    Directory of Open Access Journals (Sweden)

    Markowska Małgorzata


    Full Text Available The length of common border between two geographical units is frequently used as a basic weight in spatial analysis. The newest methodological propositions such as tests for hierarchical relations (Markowska et. al. 2014; Sokołowski et. al. 2013, regional spatial moving average and new spatial correlation coefficient (Markowska et. al. 2015 are using border lengths. In cited references new methods have been illustrated by analyses for EU NUTS2 regions. It is obvious that borders between regions belonging to different countries have different socio-economic impact than borders between regions lying in the same country. A new simple method for assesment the importance of borders is proposed in the paper. It is based on a chosen macroeconomic variable available at NUTS 2 level (e.g. GDP, infant mortality, Human Development Index. For neighboring regions bigger value is divided by smaller value giving the local importance of the given border. These measures of local border importance can be than average for borders within the same country and for borders for each pair of neighboring countries.

  19. A comparative study of the efficacy of four different bristle designs of tooth brushes in plaque removal

    Directory of Open Access Journals (Sweden)

    Sripriya N


    Full Text Available Background : The aim of the study was to compare the efficacy of four most commonly used bristle designs of toothbrushes in plaque removal. Materials and Methods : The study was a randomized 4 cell, examiner blind cross-over design assessing the plaque removal efficacy of all four brushes on a single occasion. Sixteen subjects aged 14-15 years participated in the study. On day 1 of each test period, the subjects were rendered plaque free and were asked to suspend oral hygiene practices for 24 hours. On day 2, the subjects were scored for plaque prior to brushing using the Turesky-Gilmore modification of Quigley-Hein plaque index. The subjects then brushed with the allocated toothbrush for 2 minutes and the post-brushing plaque scores were assessed. A wash-out period of 4 days was allowed between the test periods. Results : All the brushes showed a significant reduction in the post-brushing plaque scores ( p < 0.001. The mean reduction in the plaque scores for all the brushes was around 53%. The percentage plaque reduction was greater in the anterior surface than the posterior surface (59.6 ± 7.45% vs. 49.83 ± 4.35%. The percentage plaque reductions in the upper, lower, buccal and lingual surfaces were similar. No significant difference in the reduction of plaque scores between the four brushes was seen. Conclusion : The data derived from the study supports the contention of many researchers that there is no single superior design of manual toothbrush. Though minor and some site differences in favor of the brushes were seen, they were not statistically significant.

  20. The effect of food location, heat load, and intrusive medical procedures on brushing activity in dairy cows. (United States)

    Mandel, R; Whay, H R; Nicol, C J; Klement, E


    Animals allocate time and effort to a range of core (e.g., sleeping, feeding, drinking) and "luxury" (e.g., playing, exploring) activities. A luxury activity is characterized by low resilience and, as such, will be reduced when time or energy resources are limited, including under conditions of stress or discomfort. One seemingly luxurious activity available to cows on an increasing number of dairy farms is rubbing against an automated brush. The current study examined the effect of distance from food, heat load, and an intrusive medical procedure (i.e., artificial insemination and transrectal pregnancy examination) on the resilience of brush usage. The probability of using the brush decreased significantly when food was located distantly from the brush (mean=0.53) compared with days when food was located closer to the brush (mean=0.81). Brush usage also decreased at high temperature and humidity levels, with an average decrease of 0.062 brushing events for an increase of 1 temperature-humidity index unit (95% confidence interval=-0.93-0.030). In addition, a significant reduction of approximately 50% in brushing activity was observed on days of artificial insemination compared with the preceding 3d and the following 3d. These findings show that brush usage is a low resilience activity that reduces under a range of conditions. It may thus have the potential to be used as an indicator of a range of health and welfare problems in cows. Further research should be conducted to assess the sensitivity and specificity of this suggested tool and its possible contribution to the early detection of morbidity.

  1. Multicomponent membranes (United States)

    Kulprathipanja, Santi; Kulkarni, Sudhir S.; Funk, Edward W.


    A multicomponent membrane which may be used for separating various components which are present in a fluid feed mixture comprises a mixture of a plasticizer such as a glycol and an organic polymer cast upon a porous organic polymer support. The membrane may be prepared by casting an emulsion or a solution of the plasticizer and polymer on the porous support, evaporating the solvent and recovering the membrane after curing.

  2. Toothbrush abrasivity in a long-term simulation on human dentin depends on brushing mode and bristle arrangement (United States)


    Objective The aim of this study was to evaluate the susceptibility of dentin to brushing abrasion using four different toothbrushes (rotating-oscillating, sonic and two types of manual toothbrushes) with the same brushing forces. Methods Dentin samples (n = 72) were selected from 72 impacted third molars. Half of the surface of dentin samples was covered with an adhesive tape, creating a protected and a freely exposed area in the same specimen. Brushing was performed with either a: sonic (Sonicare PowerUp, Philips GmbH, Hamburg, Germany), b: oscillating-rotating (Oral B Vitality Precisions Clean, Procter & Gamble, Schwalbach am Taunus, Germany) or two different manual toothbrushes c: flat trim brush head toothbrush (Dr. Best: Original, Glaxo-Smith-Kline, Bühl, Germany) and d: rippled-shaped brush head toothbrush (Blend-a-Dent, Complete V-Interdental, Blend-a-med, Schwalbach, Germany) in a custom made automatic brushing machine. The brushing force was set to 2 N and a whitening toothpaste (RDA = 150) was used. The simulation period was performed over a calculated period to mimic a brushing behavior of two times a day brushing for eight years and six months. Dentin loss was quantitatively determined by profilometry and statistically analyzed by Wilcoxon and Mann-Whitney-U Test (p < 0.05). Results The mean (standard deviation) surface loss was 21.03 (±1.26) μm for the sonic toothbrush, 15.71 (±0.85) μm for the oscillating-rotating toothbrush, 6.13 (±1.24) μm for the manual toothbrush with flat trim brush head and 2.50 (±0.43) μm for the manual toothbrush with rippled-shaped brush head. Differences between all groups were statistically significant at p<0.05. Conclusion Using the same brushing force and a highly abrasive toothpaste, manual toothbrushes are significantly less abrasive compared to power toothbrushes for an 8.5—year simulation. PMID:28222156

  3. Amnionless function is required for cubilin brush-border expression and intrinsic factor-cobalamin (vitamin B12) absorption in vivo

    DEFF Research Database (Denmark)

    He, Qianchuan; Madsen, Mette; Kilkenney, Adam;


    Amnionless (AMN) and cubilin gene products appear to be essential functional subunits of an endocytic receptor called cubam. Mutation of either gene causes autosomal recessive Imerslund-Gräsbeck syndrome (I-GS, OMIM no. 261100) in humans, a disorder characterized by selective intestinal malabsorp......Amnionless (AMN) and cubilin gene products appear to be essential functional subunits of an endocytic receptor called cubam. Mutation of either gene causes autosomal recessive Imerslund-Gräsbeck syndrome (I-GS, OMIM no. 261100) in humans, a disorder characterized by selective intestinal...... malabsorption of cobalamin (vitamin B12) and urinary loss of several specific low-molecular-weight proteins. Vital insight into the molecular pathology of I-GS has been obtained from studies of dogs with a similar syndrome. In this work, we show that I-GS segregates in a large canine kindred due to an in...

  4. Who’s Who at the Border? A rights-based approach to identifying human trafficking at international borders

    Directory of Open Access Journals (Sweden)

    Marika McAdam


    Full Text Available International borders are widely touted as bastions in the fight against trafficking in persons. This article acknowledges the important role border officials play in preventing human trafficking, but calls for expectations to be tempered by deference to the conceptual complexity of cross-border trafficking and the migration processes involved. The fact that many trafficked victims begin their journeys as irregular or smuggled migrants highlights the challenge posed to border officials in identifying trafficked persons among the people they encounter. Indicators of trafficking generally relate to the exploitation phase, leaving border officials with little guidance as to how persons vulnerable to trafficking can be accurately identified before any exploitation has occurred. Ultimately, this paper advocates a pragmatic rights-based approach in designating anti-trafficking functions to border officials. A rights-based approach to border control acknowledges the core work of border officials as being to uphold border integrity, while ensuring that their performance of this role does not jeopardise the rights of those they intercept nor result in missed opportunities for specialists to identify trafficked persons and other vulnerable people among them.

  5. Biomimetic triblock copolymer membrane arrays: a stable template for functional membrane proteins

    DEFF Research Database (Denmark)

    Gonzalez-Perez, A.; Jensen, Karin Bagger Stibius; Vissing, Thomas;


    , we avoid low molecular weight solvents such as chloroform and toluene, which are strong protein denaturants. The membranes show a low ionic conductance and a long lifetime at room temperature. Contrast phase microscopy shows the presence of a polymer region delimited by a Plateau-Gibbs border similar......It is demonstrated that biomimetic stable triblock copolymer membrane arrays can be prepared using a scaffold containing 64 apertures of 300 μm diameter each. The membranes were made from a stock solution of block copolymers with decane as a solvent using a new deposition method. By using decane...... to what is observed in black lipid membranes. The ion-channel gramicidin A was successfully incorporated into the membrane in a functional form....

  6. Frontiers, territoriality and tensions in bordering spaces

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    María Eugenia Comerci


    Full Text Available The expansión of the agricultural frontier in the Argentine pampas implied a re-valuation of "bordering" spaces, which were considered "marginal" by capital. This paper aims at interpreting the socio-territorial impact -from both a material and a symbolic level- being caused by the expansión of the productive, business-profile [agricultural and oil] frontier in the center-west of the province of La Pampa. With the interpretative approach provided by qualitative methodologies, we intend to analyze -in a case study- how these frontier expansión processes altered and re-defined the social arena between the years 2000 and 2010, the social construction of the space and the power relations in Chos Malal

  7. The coordination of care across borders

    DEFF Research Database (Denmark)

    Kierkegaard, Patrick

    -savings, improved quality of care, avoidance of unnecessary tests, improved work efficiency, reduced waiting times and improvement in the overall efficiency of the healthcare system. Although benefits exists, healthcare organizations have experienced difficulties attaining them and overall adoption of e...... with implementing a new system, and uncertainty that the technology may actually reduce overall costs. The coordination of care across boundaries presents a plethora of issues that need to be tackled from a policy, legal, practical research perspective. This thesis attempts to address pressing issues...... with a particular focus on the implications health information exchange for the purposes of coordinating care will have on both the patient and healthcare professionals on three levels: international, national and institutional level. The findings of this thesis imply that in order for cross-border health...

  8. Obtaining the borders of urban areas

    CERN Document Server

    Comin, Cesar Henrique; Costa, Luciano da Fontoura


    The access to an ever increasing amount of information in the modern world gave rise to the development of many quantitative indicators about urban regions in the globe. Therefore, there is a growing need for a precise definition of how to delimit urban regions, so as to allow proper respective characterization and modeling. Here we present a straightforward methodology to automatically detect urban region borders. The method is based on the density of street crossings around a single seed point associated to the urban area of interest. We exemplify the potential of the methodology by characterizing the geometry and topology of 21 urban regions obtained from 8 distinct countries. The geometry is studied by employing the lacunarity measurement, which is associated to the regularity of holes contained in a pattern. The topology is analyzed by associating the betweenness centrality of the streets with their respective class, such as motorway or residential, obtained from a database.

  9. [Crossing borders. The motivation of extreme sportsmen]. (United States)

    Opaschowski, H W


    In his article "Crossing borders -- the motivation of extreme sportsmen" the author gets systematically to the bottom of the question of why extreme sportsmen voluntarily take risks and endanger themselves. Within the scope of a representative sampling 217 extreme sportsmen -- from the fields of mountain biking, trekking and free climbing, canoyning, river rafting and deep sea diving, paragliding, parachuting, bungee jumping and survival training -- give information about their personal motives. What fascinates them? The attraction of risk? The search for sensation? Or the drop out of everyday life? And what comes afterwards? Does in the end the whole life become an extreme sport? Fact is: they live extremely, because they want to move beyond well-trodden paths. To escape the boredom of everyday life they are searching for the kick, the thrill, the no-limit experience. It's about calculated risk between altitude flight and deep sea adventure.

  10. Usability in Public Services and Border Control (United States)

    Pirelli, Giuliano

    The paper starts with a brief overview of the scale of disability and associated challenges and puts them in the context of the public policy on disability. It then analyses the usability challenges in public services and border control, including the issues of accessibility, safety and communication. These need to be addressed in future policy proposals, to provide the best assistance by new technologies to elderly people and people with disabilities, avoiding creating new barriers due to incorrect or incomplete initial conception. With increasing flux of novel security technology in mass transportation systems, and particularly the use of biometric identification in airports, the challenge of usability is recognized. This paper analyses these issues in the context of users with disability in an idealized process of Simplifying Passenger Travel (SPT).

  11. Globalization and Cross-Border Labor Organizing

    Directory of Open Access Journals (Sweden)

    Ralph Armbruster


    Full Text Available The globalization of the world economy has opened up new possibilities for cross-border labor organizing. In fact, several U.S. unions are working together with unions from Mexico, Honduras, Guatemala, the Dominican Republic, Japan, South Korea, and many European nations. For example, over the last several years, UNITE (Union of Needletrades, Industrial, and Textile Employees, the AFL-CIO, and the international garment workers trade secretariat have worked directly with maquiladora workers in Honduras and the Dominican Republic. These efforts led to the formation of several labor unions and the first contracts ever negotiated in the maquiladoras in the Dominican Republic. In addition, labor rights and solidarity organizations, like the Campaign for Labor Rights, Witness for Peace, and the US/Guatemala Labor Education Project (US/GLEP, along with many other groups, have also played key roles in the formation of maquiladora unions in Nicaragua and Guatemala.


    Directory of Open Access Journals (Sweden)

    Mustafa Kurt


    Full Text Available This article discusses the influence of postmodernism on education and investigates the main effects ofpostmodern philosophy on social sciences. It is clearly stated in the article that the effects of postmodernism cannotonly be limited to art and logically it should have an effect on education as well. This effect, described as thepostmodern educational approach, emphasizes that the rudiments of popular culture should also be incorporated toeducation and therefore to curricula. Postmodern educational approach also accentuates the significance of allowing‘others’ who have never possessed the opportunity to articulate their standpoints and desires to have a say in their owneducation. The concrete reflections of postmodern educational approach can be perceived in Critical and BorderPedagogies theorized by Henry A. Giroux. Critical pedagogy aspires to educate individuals who do not acceptoccurrences as they are and are critical of the knowledge they construct all through their education. Only by this waythese individuals will be able to discover their own voices, improve their civilian consciousness by taking risks, andacquire the ability of staying alive and functioning within social relations, traditions and experiences. Border pedagogyis as well a product of postmodern philosophy. It defends counter-text as opposed to the official ones offered, presentedand imposed to learners. Counter-consciousness represents the critical analysis of how the present reads the past andhow the past informs the present. This practice of course results in the re-evaluation of memories and traditions.Memories are the stories which were forgotten or ignored with the support of preserved traditions. It is thereforeconcluded in the article that postmodern educational approach is the critical examination towards dismissing the mainnarratives and discourses which manipulate and configure the curriculum of schools. It is the struggle exercisedtowards the recognition

  13. Editorial: Human rights at the border

    Directory of Open Access Journals (Sweden)

    Sverre Molland


    Full Text Available It is with great honour that I introduce the second issue of the Anti-Trafficking Review (ATR. The first issue received an overwhelming response and has placed the journal at the forefront of rigorous analysis and debate relating to human trafficking and human rights. It raised the topic of accountability in anti-trafficking. This issue hopes to further strengthen the ATR’s position as a global, reputable journal on human trafficking. Strengthening the quality of research, analysis, and reflexivity in the trafficking sector is much needed, and I echo Anne Gallagher’s observation as guest editor of the first issue that standards in anti-trafficking research tend to be less rigorous than in other fields of study. My aim as a guest editor is to contribute to addressing this shortfall by bringing together a set of diverse and insightful articles focussing on the nexus of borders and human rights. It is also my hope that this issue will work towards narrowing the divide between practitioners and academics in anti-trafficking. This is reflected in the varied range of contributors. The last few years have witnessed a significant increase in publishing relating to human trafficking worldwide. However, there is limited measured debate and appraisal of this literature within the anti-trafficking sector. For this reason we have decided to include a book review as a way of highlighting recent major publications. The question of borders, migration control, trafficking and human rights raise contested and controversial questions. The editorial team has attempted to include different perspectives, reflected in the debate section in particular. Needless to say, all papers have been subject to double blind peer review.

  14. Cross-border firing and injury patterns

    Directory of Open Access Journals (Sweden)

    Nital Gupta


    Full Text Available Introduction: Cross-border firing are increasingly being common in the modern era. The injuries resulting from these low intensity conflicts are a source of anxiety among treating physicians and their respective governments. The provisions are required to minimise the suffering of the victims viz. Mode of injuries, mortality patterns, adequacy of treatment at pre-hospital and tertiary care hospital and provisions to decrease morbidity and mortality for the people living in these areas. Materials and Methods: A retrospective study was conducted in GMCH, Jammu who suffered injuries due to cross border firing in the month of October, 2014. 68 patients were reported in the causality wing. All the patients were referred from level 2 trauma centre. There were 51 males and 17 females out of which 5 were children. The cause of injury, involvement of organ system, cause of mortality and morbidity and loopholes in prehospital management were identified. Results: Sharpnel were the most common cause of injury followed by indirect trauma. The common cause of mortality was abdominal and thoracic injuries. There were 4 deaths at hospital 2 of which were brought dead and 2 died during the course of treatment. There were twenty patients with extremity injuries, fourteen with chest trauma, eleven with abdomen including parineal injuries, three with head injuries, eight with ENT injuries, three with eye injuries and nine with splinters in the back out of which two were in the spinal canal. Conclusion: Prehospital stabilisation, early transport, in-transit resuscitation, immediate surgery if required and implementation of triage model and ATLS protocol has been the key to reduce mortality and morbidity.

  15. Cross-border mobility, unfamiliarity and development policy in Europe

    NARCIS (Netherlands)

    Spierings, B.; Velde, M. van der


    In this special issue, we seek to explore experiences, performances and effects of both “unfamiliarity” and “familiarity” across a diversity of inner and outer borders of the European Union. In EU integration discourse, cross-border unfamiliarity is usually considered to obstruct international mobil

  16. 77 FR 38076 - U.S. Customs and Border Protection (United States)


    ... SECURITY U.S. Customs and Border Protection Accreditation and Approval of SGS North America, Inc., as a Commercial Gauger and Laboratory AGENCY: U.S. Customs and Border Protection, Department of Homeland Security... petroleum and petroleum products, organic chemicals and vegetable oils for customs purposes, in...

  17. 76 FR 65207 - U.S. Customs and Border Protection (United States)


    ... SECURITY U.S. Customs and Border Protection Notice of Cancellation of Customs Broker Licenses AGENCY: U.S. Customs and Border Protection, U.S. Department of Homeland Security. ACTION: General notice. SUMMARY: Pursuant to section 641 of the Tariff Act of 1930, as amended, (19 U.S.C. 1641) and the U.S. Customs...

  18. 76 FR 50883 - U.S. Customs and Border Protection (United States)


    ... SECURITY U.S. Customs and Border Protection DEPARTMENT OF THE TREASURY 19 CFR Part 159 RIN 1515-AD67 (formerly RIN 1505-AC21) Courtesy Notice of Liquidation AGENCY: Customs and Border Protection, Department of... of the Code of Federal Regulations (``CFR'') pertaining to the method by which U.S. Customs...

  19. 15 CFR 30.17 - Customs and Border Protection regulations. (United States)


    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Customs and Border Protection regulations. 30.17 Section 30.17 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade... Requirements § 30.17 Customs and Border Protection regulations. Refer to the DHS's CBP regulations, 19 CFR...

  20. 77 FR 59206 - U.S. Customs and Border Protection (United States)


    ... SECURITY U.S. Customs and Border Protection Agency Information Collection Activities: Foreign Assembler's Declaration AGENCY: U.S. Customs and Border Protection (CBP), Department of Homeland Security. ACTION: 60-day... November 26, 2012, to be assured of consideration. ADDRESSES: Direct all written comments to U.S....